Tradeoff between the Brillouin and transverse mode instabilities in Yb-doped fiber amplifiers

The Brillouin instability (BI) due to stimulated Brillouin scattering (SBS) and the transverse (thermal) mode instability (TMI) due to stimulated thermal Rayleigh scattering (STRS) limit the achievable power in high-power lasers and amplifiers. The pump power threshold for BI increases as the core diameter increases, but the threshold for TMI may decrease as the core diameter increases. In this paper, we use a multi-time-scale approach to simultaneously model BI and TMI, which gives us the ability to find the fiber diameter with the highest power threshold. We formulate the equations to compare the thresholds of the combined and individual TMI and BI models. At the pump power threshold and below, there is a negligible difference between the full and individual models, as BI and TMI are not strong enough to interact with each other. The highest pump threshold occurs at the optimal core size of 43 µm for the simple double-clad geometry that we considered. We found that both effects contribute equally to the threshold, and the full BI and TMI model yields a similar threshold as the BI or TMI model alone. However, once the reflectivity is sufficiently large, we find in the full BI and TMI model that BI may trigger TMI and reduce the TMI threshold to a value lower than is predicted in simulations with TMI alone. This result cannot be predicted by models that consider BI and TMI separately. Our approach can be extended to more complex geometries and used for their optimization.

Tale of 22 cities: utilisation patterns and content of maternal care in large African cities

Introduction

Globally, the majority of births happen in urban areas. Ensuring that women and their newborns benefit from a complete package of high-quality care during pregnancy, childbirth and the postnatal period present specific challenges in large cities. We examine health service utilisation and content of care along the maternal continuum of care (CoC) in 22 large African cities.

Methods

We analysed data from the most recent Demographic and Health Survey (DHS) since 2013 in any African country with at least one city of ≥1 million inhabitants in 2015. Women with live births from survey clusters in the most populous city per country were identified. We analysed 17 indicators capturing utilisation, sector and level of health facilities and content of three maternal care services: antenatal care (ANC), childbirth care and postnatal care (PNC), and a composite indicator capturing completion of the maternal CoC. We developed a categorisation of cities according to performance on utilisation and content within maternal CoC.

Results

The study sample included 25 326 live births reported by 19 217 women. Heterogeneity in the performance in the three services was observed across cities and across the three services within cities. ANC utilisation was high (>85%); facility-based childbirth and PNC ranged widely, 77%–99% and 29%–94%, respectively. Most cities showed inconsistent levels of utilisation and content across the maternal CoC, Cotonou and Accra showed relatively best and Nairobi and Ndjamena worst performance.

Conclusion

This exploratory analysis showed that many DHS can be analysed on the level of large African cities to provide actionable information about the utilisation and content of the three maternal health services. Our comparative analysis of 22 cities and proposed typology of best and worst-performing cities can provide a starting point for extracting lessons learnt and addressing critical gaps in maternal health in rapidly urbanising contexts.

Accurate and efficient modeling of the transverse mode instability in high energy laser amplifiers

We study the transverse mode instability (TMI) in the limit where a single higher-order mode (HOM) is present. We demonstrate that when the beat length between the fundamental mode and the HOM is small compared to the length scales on which the pump amplitude and the optical mode amplitudes vary, TMI is a three-wave mixing process in which the two optical modes beat with the phase-matched component of the index of refraction that is induced by the thermal grating. This limit is the usual limit in applications, and in this limit TMI is identified as a stimulated thermal Rayleigh scattering (STRS) process. We demonstrate that a phase-matched model that is based on the three-wave mixing equations can have a large computational advantage over current coupled mode methods that must use longitudinal step sizes that are small compared to the beat length.

Examining user fee reductions in public primary healthcare facilities in Kenya, 1997-2012: effects on the use and content of antenatal care

BACKGROUND

In 2004, The Kenyan government removed user fees in public dispensaries and health centers and replaced them with registration charges of 10 and 20 Kenyan shillings (2004 $US 0.13 and $0.25), respectively. This was termed the 10/20 policy. We examined the effect of this policy on the coverage, timing, source, and content of antenatal care (ANC), and the equity in these outcomes.

METHODS

Data from the 2003, 2008/9 and 2014 Kenya Demographic and Health Surveys were pooled to investigate women's ANC care-seeking. We conducted an interrupted time series analysis to assess the impact of the 10/20 policy on the levels of and trends in coverage for 4+ ANC contacts among all women; early ANC initiation and use of public facility-based care among 1+ ANC users; and use of public primary care facilities and receipt of good content, or quality, of ANC among users of public facilities. All analyses were conducted at the population level and separately for women with higher and lower household wealth.

RESULTS

The policy had positive effects on use of 4+ ANC among both better-off and worse-off women. Among users of 1+ ANC, the 10/20 policy had positive effects on early ANC initiation at the population-level and among better-off women, but not among the worse-off. The policy was associated with reduced use of public facility-based ANC among better-off women. Among worse-off users of public facility-based ANC, the 10/20 policy was associated with reduced use of primary care facilities and increased content of ANC.

CONCLUSIONS

This study highlights mixed findings on the impact of the 10/20 policy on ANC service-seeking and content of care. Given the reduced use of public facilities among the better-off and of primary care facilities among the worse-off, this research also brings into question the mechanisms through which the policy achieved any benefits and whether reducing user fees is sufficient for equitably increasing healthcare access.

Initiation and continuity of maternal healthcare: examining the role of vouchers and user-fee removal on maternal health service use in Kenya

This study explores the relationship between two health financing initiatives on women's progression through the maternal health continuum in Kenya: a subsidized reproductive health voucher programme (2006-16) and the introduction of free maternity services in all government facilities (2013). Using cross-sectional survey data, we ran three multivariable logistic regression models examining the effects of the voucher programme, free maternity policy, health insurance and other determinants on (1) early antenatal care (ANC) initiation (first visit within the first trimester of pregnancy), (2) receiving continuous care (1+ ANC, facility birth, 1+ post-natal care (PNC) check) and (3) completing the maternal health pathway as recommended (4+ ANC, facility birth, 1+ PNC, with first check occurring within 48 h of delivery). Full implementation of the voucher programme was positively associated with receiving continuous care among users of 1+ ANC [interaction term adjusted odds ratio (aOR): 1.33, P = 0.014]. Early ANC initiation (aOR: 1.32, P = 0.001) and use of private sector ANC (aOR: 1.93, P < 0.001) were also positively associated with use of continuous care among ANC users. Among continuous care users, early ANC was associated with increased odds of completing the maternal health pathway as recommended (aOR: 3.80, P < 0.001). Higher parity was negatively associated with all three outcomes, while having health insurance was positively associated with each outcome. The impact of other sociodemographic factors such as maternal age, education, wealth quintile, urban residence, and employment varied by outcome; however, the findings generally suggest that marginalized women faced greater barriers to early ANC initiation and continuity of care. Health financing and women's timing and source of ANC are strongly related to their subsequent progression through the maternal health pathway. To increase continuity of care and improve maternal health outcomes, policymakers must therefore focus on equitably reducing financial and other barriers to care seeking and improving quality of care throughout the continuum.

A new approach to assess the capability of health facilities to provide clinical care for sexual violence against women: a pilot study

Several tools have been developed to collect information on health facility preparedness to provide sexual violence response services; however, little guidance exists on how this information can be used to better understand which functions a facility can perform. Our study therefore aims to propose a set of signal functions that provide a framework for monitoring the availability of clinical sexual violence services. To illustrate the potential insights that can be gained from using our proposed signal functions, we used the framework to analyse data from a health facility census conducted in Central Province, Zambia. We collected the geographic coordinates of health facilities and police stations to assess women's proximity to multi-sectoral sexual violence response services. We defined three key domains of clinical sexual violence response services, based on the timing of the visit to the health facility in relation to the most recent sexual assault: (1) core services, (2) immediate care, and (3) delayed and follow-up care. Combining information from all three domains, we estimate that just 3% of facilities were able to provide a comprehensive response to sexual violence, and only 16% could provide time-sensitive immediate care services such as HIV post-exposure prophylaxis and emergency contraception. Services were concentrated in hospitals, with few health centres and no health posts fulfilling the signal functions for any of the three domains. Only 23% of women lived within 15 km of comprehensive clinical sexual violence health services, and 38% lived within 15 km of immediate care. These findings point to a need to develop clear strategies for decentralizing sexual violence services to maximize coverage and ensure equity in access. Overall, our findings suggest that our proposed signal functions could be a simple and valuable approach for assessing the availability of clinical sexual violence response services, identifying areas for improvement and tracking improvements over time.

Who pays and how much? A cross-sectional study of out-of-pocket payment for modern contraception in Kenya

OBJECTIVES

Out-of-pocket (OOP) payment for modern contraception is an understudied component of healthcare financing in countries like Kenya, where wealth gradients in met need have prompted efforts to expand access to free contraception. This study aims to examine whether, among public sector providers, the poor are more likely to receive free contraception and to compare how OOP payment for injectables and implants-two popular methods-differs by public/private provider type and user's sociodemographic characteristics.

DESIGN, SETTING AND PARTICIPANTS

Secondary analyses of nationally representative, cross-sectional household data from the 2014 Kenya Demographic and Health Survey. Respondents were women of reproductive age (15-49 years). The sample comprised 5717 current modern contraception users, including 2691 injectable and 1073 implant users with non-missing expenditure values.

MAIN OUTCOME

Respondent's self-reported source and payment to obtain their current modern contraceptive method.

METHODS

We used multivariable logistic regression to examine predictors of free public sector contraception and compared average expenditure for injectable and implant. Quintile ratios examined progressivity of non-zero expenditure by wealth.

RESULTS

Half of public sector users reported free contraception; this varied considerably by method and region. Users of implants, condoms, pills and intrauterine devices were all more likely to report receiving their method for free (p<0.001) compared with injectable users. The poorest were as likely to pay for contraception as the wealthiest users at public providers (OR: 1.10, 95% CI: 0.64 to 1.91). Across all providers, among users with non-zero expenditure, injectable and implant users reported a mean OOP payment of Kenyan shillings (KES) 80 (US$0.91), 95% CI: KES 78 to 82 and KES 378 (US$4.31), 95% CI: KES 327 to 429, respectively. In the public sector, expenditure was pro-poor for injectable users yet weakly pro-rich for implant users.

CONCLUSIONS

More attention is needed to targeting subsidies to the poorest and ensuring government facilities are equipped to cope with lost user fee revenue.

Two decades of antenatal and delivery care in Uganda: a cross-sectional study using Demographic and Health Surveys

Background

Uganda halved its maternal mortality to 343/100,000 live births between 1990 and 2015, but did not meet the Millennium Development Goal 5. Skilled, timely and good quality antenatal (ANC) and delivery care can prevent the majority of maternal/newborn deaths and stillbirths. We examine coverage, equity, sector of provision and content of ANC and delivery care between 1991 and 2011.

Methods

We conducted a repeated cross-sectional study using four Uganda Demographic and Health Surveys (1995, 2000, 2006 and 2011).Using the most recent live birth and adjusting for survey sampling, we estimated percentage and absolute number of births with ANC (any and 4+ visits), facility delivery, caesarean sections and complete maternal care. We assessed socio-economic differentials in these indicators by wealth, education, urban/rural residence, and geographic zone on the 1995 and 2011 surveys. We estimated the proportions of ANC and delivery care provided by the public and private (for-profit and not-for-profit) sectors, and compared content of ANC and delivery care between sectors. Statistical significance of differences were evaluated using chi-square tests.

Results

Coverage with any ANC remained high over the study period (> 90% since 2001) but was of insufficient frequency; < 50% of women who received any ANC reported 4+ visits. Facility-based delivery care increased slowly, reaching 58% in 2011. While significant inequalities in coverage by wealth, education, residence and geographic zone remained, coverage improved for all indicators among the lowest socio-economic groups of women over time. The private sector market share declined over time to 14% of ANC and 25% of delivery care in 2011. Only 10% of women with 4+ ANC visits and 13% of women delivering in facilities received all measured care components.

Conclusions

The Ugandan health system had to cope with more than 30,000 additional births annually between 1991 and 2011. The majority of women in Uganda accessed ANC, but this contact did not result in care of sufficient frequency, content, and continuum of care (facility delivery). Providers in both sectors require quality improvements. Achieving universal health coverage and maternal/newborn SDGs in Uganda requires prioritising poor, less educated and rural women despite competing priorities for financial and human resources.

Electronic supplementary material

The online version of this article (10.1186/s12913-018-3546-3) contains supplementary material, which is available to authorized users.

Meeting need vs. sharing the market: a systematic review of methods to measure the use of private sector family planning and childbirth services in sub-Saharan Africa

BACKGROUND

Ensuring universal access to maternal and reproductive health services is critical to the success of global efforts to reduce poverty and inequality. Engaging private providers has been proposed as a strategy for increasing access to healthcare in low- and middle-income countries; however, little consensus exists on how to estimate the extent of private sector use. Using research from sub-Saharan Africa, this study systematically compares and critiques quantitative measures of private sector family planning and childbirth service use and synthesizes evidence on the role of the private sector in the region.

METHODS

We conducted a systematic review of the Medline, Global Health, and Popline databases. All studies that estimated use of private sector of family planning or childbirth services in one or more sub-Saharan African countries were included in this review. For each study, we extracted data on the key study outcomes and information on the methods used to estimate private sector use.

RESULTS

Fifty-three papers met our inclusion criteria; 31 provided outcomes on family planning, and 26 provided childbirth service outcomes. We found substantial methodological variation between studies; for instance, while some reported on service use from any private sector source, others distinguished private sector providers either by their profit orientation or position within or outside the formal medical sector. Additionally, studies measured the use of private sector services differently, with some estimating the proportion of need met by the private sector and others examining the sector's share among the market of service users. Overall, the estimates suggest that the private sector makes up a considerable portion (> 20%) of the market for family planning and childbirth care, but its role in meeting women's need for these services is fairly low (< 10%).

CONCLUSIONS

Many studies have examined the extent of private sector family planning and childbirth service provision; however, inconsistent methodologies make it difficult to compare results across studies and contexts. Policymakers should consider the implications of both private market share and coverage estimates, and be cautious in interpreting data on the scale of private sector health service provision without a clear understanding of the methodology.

Does supportive legislation guarantee access to pregnancy termination and postabortion care services? Findings from a facility census in Central Province, Zambia

Introduction

Zambia is one of the few countries in Africa to permit termination of pregnancy (TOP) on a wide range of grounds. However, substantial barriers remain to TOP and postabortion care (PAC).

Methods

We conducted a census of 153 facilities between March and May 2016. We defined facilities according to whether they met basic and/or comprehensive signal functions criteria for TOP and PAC. We linked our facility data to census data to estimate geographic accessibility under different policy scenarios.

Results

Overall, 16% of facilities reported they had performed a TOP and 39% performed a PAC in the last year. Facilities were twice as likely to use medical methods for TOP compared with surgical methods, and four times more likely for PAC. Considerably more facilities had performed TOP or PAC than met the basic or comprehensive signal functions criteria, indicating services were being performed in facilities below essential quality standards. Under current Zambian law for non-emergency scenarios, 21% of women in Central Province lived within 15 km of a facility with basic capability to provide TOP; if midlevel providers were trained to provide TOP, this would increase to 36%.

Conclusion

A supportive legislative framework is essential, but not in itself sufficient, for adequate access to services. Training midlevel providers, in line with WHO guidance, and ensuring equipment is available in primary care can increase accessibility of TOP and PAC. While both medical and surgical methods need to be available, medical abortion is a safe and effective method that can be provided in low-resource settings.

Evaluating the impact of a maternal health voucher programme on service use before and after the introduction of free maternity services in Kenya: a quasi-experimental study

INTRODUCTION

From 2006 to 2016, the Government of Kenya implemented a reproductive health voucher programme in select counties, providing poor women subsidised access to public and private sector care. In June 2013, the government introduced a policy calling for free maternity services to be provided in all public facilities. The concurrent implementation of these interventions presents an opportunity to provide new insights into how users adapt to a changing health financing and service provision landscape.

METHODS

We used data from three cross-sectional surveys to assess changes over time in use of 4+ antenatal care visits, facility delivery, postnatal care and maternal healthcare across the continuum among a sample of predominantly poor women in six counties. We conducted a difference-in-differences analysis to estimate the impact of the voucher programme on these outcomes, and whether programme impact changed after free maternity services were introduced.

RESULTS

Between the preintervention/roll-out phase and full implementation, the voucher programme was associated with a 5.5% greater absolute increase in use of facility delivery and substantial increases in use of the private sector for all services. After free maternity services were introduced, the voucher programme was associated with a 5.7% higher absolute increase in use of the recommended package of maternal health services; however, disparities in access to facility births between voucher and comparison counties declined. Increased use of private sector services by women in voucher counties accounts for their greater access to care across the continuum.

CONCLUSIONS

Our findings show that the voucher programme is associated with a modest increase in women's use of the full continuum of maternal health services at the recommended timings after free maternity services were introduced. The greater use of private sector services in voucher counties also suggests that there is need to expand women's access to acceptable and affordable providers.

Who Meets the Contraceptive Needs of Young Women in Sub-Saharan Africa?

PURPOSE

Despite efforts to expand contraceptive access for young people, few studies have considered where young women (age 15-24) in low- and middle-income countries obtain modern contraceptives and how the capacity and content of care of sources used compares with older users.

METHODS

We examined the first source of respondents' current modern contraceptive method using the most recent Demographic and Health Survey since 2000 for 33 sub-Saharan African countries. We classified providers according to sector (public/private) and capacity to provide a range of short- and long-term methods (limited/comprehensive). We also compared the content of care obtained from different providers.

RESULTS

Although the public and private sectors were both important sources of family planning (FP), young women (15-24) used more short-term methods obtained from limited-capacity, private providers, compared with older women. The use of long-term methods among young women was low, but among those users, more than 85% reported a public sector source. Older women (25+) were significantly more likely to utilize a comprehensive provider in either sector compared with younger women. Although FP users of all ages reported poor content of care across all providers, young women had even lower content of care.

CONCLUSIONS

The results suggest that method and provider choice are strongly linked, and recent efforts to increase access to long-term methods among young women may be restricted by where they seek care. Interventions to increase adolescents' access to a range of FP methods and quality counseling should target providers frequently used by young people, including limited-capacity providers in the private sector.

Pathways to increased coverage: an analysis of time trends in contraceptive need and use among adolescents and young women in Kenya, Rwanda, Tanzania, and Uganda

BACKGROUND

Despite efforts to make contraceptive services more "youth friendly," unmet need for contraception among young women in sub-Saharan Africa remains high. For health systems to effectively respond to the reproductive health needs of a growing youth population, it is imperative to understand their contraceptive needs and service seeking practices. This paper describes changes over time in contraceptive need, use, and sources of care among young women in four East African countries.

METHODS

We used three rounds of DHS data from Kenya, Rwanda, Tanzania, and Uganda to examine time trends from 1999 to 2015 in met need for modern contraception, method mix, and source of care by sector (public or private) and type of provider among young women aged 15-24 years. We assessed disparities in contraceptive coverage improvements over time between younger (15-24 years) and older women (25-49 years) using a difference-in-differences approach.

RESULTS

Met need for contraception among women aged 15-24 years increased over time, ranging from a 20% increase in Tanzania to more than a 5-fold increase in Rwanda. Improvements in met need were greater among older women compared to younger women in Rwanda and Uganda, and higher among younger women in Kenya. Injectables have become the most popular contraceptive choice among young women, with more than 50% of modern contraceptive users aged 15-24 years currently using the method in all countries except for Tanzania, where condoms and injectables are used by 38% and 35% of young users, respectively. More than half of young women in Tanzania and Uganda receive contraceptives from the private sector; however, while the private sector played an important role in meeting the growing contraceptive needs among young women in Tanzania, increased use of public sector services drove expanded access in Kenya, Rwanda, and Uganda.

CONCLUSIONS

Our study shows that contraceptive use increased among young East African women, yet, unmet need remains high. As youth populations continue to grow, governments must develop more targeted strategies for expanding access to reproductive health services for young women. Engaging the private sector and task-shifting to lower-level providers offer promising approaches; however, additional research is needed to identify the key facilitators and barriers to the success of these strategies in different contexts.

Comparing the use and content of antenatal care in adolescent and older first-time mothers in 13 countries of west Africa: a cross-sectional analysis of Demographic and Health Surveys

BACKGROUND

West Africa has the highest proportion of married adolescents, and the highest adolescent childbirth rate and maternal death rate in sub-Saharan Africa. However, few studies have focused on the type and quality of health care accessed by pregnant young women in countries in this subregion.

METHODS

We obtained data from Demographic and Health Surveys done between 2010 and 2014, to compare the use, timing, source, and components of antenatal care between adolescent and older first-time mothers in 13 west African countries. The sample included primiparous women who were aged 15-49 years with a livebirth in the 5-year survey recall period, and women were assigned to one of three groups on the basis of age at the time of childbirth: adolescent (10-19 years), young adults (20-24 years), or adults (25 years or older). We calculated the percentage of women who: attended at least one antenatal care visit, completed at least one visit during the first trimester of pregnancy, attended four or more appointments in antenatal care, and received four components of antenatal care (blood pressure measurement, urine tests, blood tests, and information on complications), as well as the sector where the women received care. We primarily report the comparison between adolescents and young adults.

FINDINGS

In 2016, we acquired data from the Demographic Health Surveys from 13 west African countries between 2010 and 2014 on primiparous women. The study sample was 19 211 women, of whom 10 025 (52%) were adolescents, 6099 (32%) were young adults, and 3087 (16%) were adults. Overall, 17 386 (91%) of 19 211 first-time mothers made use of antenatal care facilities on at least one occasion. 3597 (41%) of 8741 adolescents compared with 8202 (47%) of all 17 386 women began the use of antenatal care during the first trimester. Across west Africa, 5430 (62%) of 8741 adolescents had four or more antenatal care visits compared with 4067 (71%) of 5717 young adults and 2358 (81%) of 2928 adults. Of those who had four or more visits to antenatal care, 2779 (51%) of 5430 adolescents received all the antenatal care components examined compared with 2488 (61%) of 4067 young adults and 1600 (68%) of 2358 adults. Although most women received antenatal care in the public sector, in nine of the 13 countries, the proportion of women that used the private sector was higher in older mothers.

INTERPRETATION

Although a large percentage of west African adolescents use some antenatal care for their first birth, they seek care later, make fewer visits during pregnancy, and receive fewer components of care than older first-time mothers. Governments must ensure the pregnancy care accessed by adolescent mothers is of high quality and tailored to meet their needs.

FUNDING

MSD for Mothers.

Motivations for entering and remaining in volunteer service: findings from a mixed-method survey among HIV caregivers in Zambia

BACKGROUND

A high burden of HIV in many sub-Saharan African countries has triggered renewed interest in volunteer-based community health programmes as a way to support treatment roll-out and to deliver services to children orphaned due to HIV. This study was undertaken as an evaluation of a USAID project implemented by a consortium of 7 NGOs operating in 52 Zambian districts. We aimed to examine motivations for becoming volunteer caregivers, experiences in service and commitment to continue volunteering in the future.

METHODS

A mixed-method survey approach was adopted incorporating close- and open-ended questions. District selection (3 of 52) was purposive, based on representation of urban, peri-urban and rural volunteers from a mix of the consortium's NGO affiliates. Individual volunteer recruitment was achieved via group information sessions and opportunistic sampling was used to reach a quota (~300) per study district. All participants provided written informed consent.

RESULTS

A total of 758 eligible caregivers were surveyed. Through parallel analyses of different data types and cross-over mixed analyses, we found shifting patterns in motivations across question type, question topic and question timing. In relation to motivations for entering service, responses to both open- and close-ended questions highlighted the importance of value-oriented functions and higher order social aspirations such as "helping society" or "humanity". However, 70% of participants also agreed to at least one close-ended economic motivation statement and nearly a quarter (23%) agreed to all four. Illustrating economic need, as well as economic motivation, over half (53%) the study respondents agreed that they had become a volunteer because they needed help from the project. Volunteers with lower and mid-level standard-of-living scores were significantly more likely to agree with economic motivation statements.

CONCLUSIONS

Reliance by national and international health programmes on volunteer workforces is rooted in the assumption that volunteers are less costly and thus more sustainable than maintaining a professional cadre of community health workers. Understanding individuals' motivations for entering and remaining in volunteer service is therefore critical for programme planners and policy makers. This study demonstrated that volunteers had complex motivations for entering and continuing service, including "helping" and other pro-social values, but also manifest expectations of and need for material support. These findings contribute to evidence in support of various reforms needed to strengthen the viability and sustainability of volunteer-dependent services including the need to acknowledge and plan for the economic vulnerability of so-called volunteer recruits.

Compact, hydrophilic, lanthanide-binding tags for paramagnetic NMR spectroscopy

The design, synthesis and evaluation of four novel lanthanide-binding tags for paramagnetic NMR spectroscopy are reported.

The design, synthesis and evaluation of four novel lanthanide-binding tags for paramagnetic NMR spectroscopy are reported. Each tag is based on the ((2S,2′S,2′′S,2′′′S)-1,1′,1′′,1′′′-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetrakis(propan-2-ol)) scaffold, featuring small chiral alcohol coordinating pendants to minimise the size and hydrophobic character of each tag. The tags feature different linkers of variable length for conjugation to protein via a single cysteine residue. Each tag's ability to induce pseudocontact shifts (PCS) was assessed on a ubiquitin A28C mutant. Two enantiomeric tags of particular note, C7 and C8, produced significantly larger Δχ-tensors compared to a previously developed tag, C1, attributed to the extremely short linker utilised, limiting the mobility of the bound lanthanide ion. The C7 and C8 tags' capacity to induce PCSs was further demonstrated on GB1 Q32C and 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) S112C/C80A mutants. Whilst factors such as the choice of lanthanide ion, pH and site of conjugation influence the size of the PCSs obtained, the tags represent a significant advance in the field.

State-of-the-art methodologies in alcohol-related health services research

Many of the failures to replicate clinical findings of treatment efficacy in more realistic field and community settings can be attributed to inappropriate research designs and other methodological shortcomings. In order to increase research designers' awareness of existing methodologies that may be better suited to answer the critical questions inherent in health services research on alcohol-related issues, the National Institute on Alcohol Abuse and Alcoholism (NIAAA) convened an expert conference with three specific goals; (1) to identify the critical issues involved in alcohol services research; (2) to develop a primer that explicated each key area; and (3) to compile the resulting primers into an accessible resource for researchers, policy makers and consumers. The 9 papers in this special supplement are the product of that conference and are organized broadly around three phases of the research process: study design and implementation, data collection and use, and the analysis and interpretation of data. A final summary paper discusses the issues and offers a synthesis of key themes as well as some direction for the future.

Twenty-five strategies for improving the design, implementation and analysis of health services research related to alcohol and other drug abuse treatment

While some aspects of addiction can be studied in laboratory or controlled settings, the study of long-term recovery management and the health services that support it requires going out into the community and dealing with populations and systems that are much more diverse and less under our control. This in turn raises many methodological challenges for the health service researchers studying alcohol and other drug abuse treatment. This paper identifies some of these challenges related to the design, measurement, implementation and effectiveness of health services research. It then recommends 25 strategies (and key primers) for addressing them: (1) identifying in advance all stakeholders and issues; (2) developing conceptual models of intervention and context; (3) identifying the population to whom the conclusions will be generalized; (4) matching the research design to the question; (5) conducting randomized experiments only when appropriate and necessary; (6) balancing methodological and treatment concerns; (7) prioritizing analysis plans and increasing design sensitivity, (8) combining qualitative and quantitative methods; (9) identifying the four basic types of measures needed; (10) identifying and using standardized measures; (11) carefully balancing measurement selection and modification; (12) developing and evaluating modified and new measures when necessary; (13) identifying and tracking major clinical subgroups; (14) measuring and analyzing the actual pattern of services received; (15) incorporating implementation checks into the design; (16) incorporating baseline measures into the intervention; (17) monitoring implementation and dosage as a form of quality assurance; (18) developing procedures early to facilitate tracking and follow-up of study participants; (19) using more appropriate representations of the actual experiment; (20) using appropriate and sensitive standard deviation terms; (21) partialing out variance due to design or known sources prior to estimating experimental effect sizes; (22) using dimensional, interval and ratio measures to increase sensitivity to change; (23) using path or structural equation models; (24) integrating qualitative and quantitative analysis into reporting; and (25) using quasi-experiments, economic or organizational studies to answer other likely policy questions. Most of these strategies have been tried and tested in this and other areas, but are not widely used. Improving the state of the art of health services research and bridging the gap between research and practice do not depend upon using the most advanced methods, but rather upon using the most appropriate methods.

Cross-phase modulation and multiwavelength adiabatic solitons

In an experimental demonstration of four-channel, wavelength-division-multiplexed repeaterless transmission over 235 km, adiabatic soliton propagation allows for precise spectral characterization of cross-phase modulation effects during initial soliton collisions. Theoretical predictions of the spectral shifts that occur are verified for ultrashort solitons. The relationship between the frequency shift and the initial pulse separation is confirmed by measurement of the bit-error ratio as the pulse spacing is varied at the fiber input. Adiabatic expansion of narrow solitons may help to alleviate the channel restrictions that are required for prevention of soliton collisions at the fiber input.

Patterns of HIV risk and alcohol use among African-American crack abusers

Although the association between heavy alcohol use and HIV risk has been studied in treatment populations, we know little about patterns of alcohol use and HIV risk among out-of-treatment African-American drug users. This study examines the extent to which alcohol use affects HIV risk in a sample of 495 African-American crack users who did not inject drugs. We present differences between levels of alcohol and crack use with regard to sexual practices (including sex while impaired), number of partners, frequency of sexual activity, and condom use. The findings suggest an intimate relationship between alcohol use, crack use, and sexual risks for HIV infection. Respondents who reported frequent use (15-30 days in the last 30 days) of alcohol, crack, or both displayed significantly greater risk than those who reported less than frequent use.

Symptoms of dependence, multiple substance use, and labor market outcomes

The prevalence and costs of alcohol and drug disorders pose a serious social concern for policymakers. In this paper, we use data from the National Household Surveys on Drug Abuse (NHSDA) to estimate simple descriptive statistics and analysis of variance (ANOVA) models of the relationship between symptoms of dependence and labor market outcomes for alcohol, cigarettes, marijuana, and other illicit drugs. For men, we find that substance use with symptoms of dependence is associated with both lower employment rates and fewer hours of work. For women, we find that substance use with symptoms of dependence is associated with lower employment rates, but we find no consistent evidence of a relationship between symptoms of dependence and the number of hours worked. Finally, all of our point estimates are smaller in magnitude when we control for multiple substance use, suggesting that comorbidities play a critical role in the relationship between substance use and labor market outcomes. Our results suggest that policymakers and researchers should consider the full spectrum of substance use and dependence rather than focusing on the simple use of a single substance.

Cluster analysis of HIV intervention outcomes among substance-abusing women

The study described here presents an innovative approach to analyzing intervention outcomes among women substance abusers participating in a national HIV prevention research study funded by the National Institute on Drug Abuse. We used cluster analysis to divide the women in our sample (N=557) into four distinct subgroups predominantly characterized by differences in drug use, injecting risk, sexual behaviors, and drug and sexual risk combined. The four subgroups resulting from this process were primary crack-using women, primary needle-using women, high-frequency needle-using women, and women with multiple drug and sex risk behaviors. Our analysis focuses on changes in self-reported risk behaviors from baseline to 6-month follow-up. In general, the results clearly indicate that the women are heterogeneous; that is, the subgroups exhibit varying patterns of drug use, injecting risk, sexual behavior, and HIV seropositivity. Significant outcomes were found in many areas, indicating positive changes in risk behaviors. The two smaller subgroups of women--high-frequency needle users and those in the multiple-risk behavior subgroup--reported the highest rate of high-risk behaviors and seropositivity but also showed the greatest change at follow-up. A particularly important finding resulting from our analytical approach is that well over half the women in our sample were primary crack users (n=313). This finding is even more significant in light of the fact that the Cooperative Agreement specifically tried to include 70% or more participants who were injectors. Although the rate of HIV seropositivity is not as high for this crack-using subgroup as for the two smaller needle-using subgroups, a greater number of "women who are HIV positive" are in this primary crack-using subgroup than in all the other subgroups. Most of the crack-using women reported that they were not currently injecting drugs and never shared needles, but 10% were seropositive for HIV, suggesting that their risk comes primarily from sexual behaviors. Behaviors in this larger subgroup of women did not change as dramatically as those of women in the smaller subgroups; however, the women did show improvement in areas related to indirect risk (e.g., alcohol and crack use) and in several areas where change is most needed (e.g., trading sex for drugs and using condoms). The results demonstrate a promising alternative approach to analyzing substance abuse and HIV risk behaviors, and they suggest the need for further research on alternative interventions for women with different patterns of risk behaviors.

A cluster analysis of not-in-treatment drug users at risk for HIV infection

The purpose of the analysis described here was to classify not-in-treatment drug users participating in the National Institute on Drug Abuse (NIDA)-sponsored Cooperative Agreement study into several "homogeneous" HIV risk groups using cluster analysis. Data for this analysis (N=17,778) were collected at 19 study sites in the United States and Puerto Rico. Measures selected for the cluster analysis were limited to (a) current drug use and HIV risk behaviors, (b) mutually exclusive behaviors, (c) behaviors directly related to HIV risk, and (d) behaviors that were not statistically rare. Eight homogeneous HIV risk clusters were produced. Crack cocaine use was the most distinguishing feature of three clusters. Another three clusters were distinguishable by drug injection and needle use practices. Two additional clusters could not be grouped with either the crack- or the injection-dominant clusters. Prostitution was the most distinguishing risk behavior of one of these clusters, and extremely high drug injection frequencies and relative rates of risky needle use characterized the other. Composition of the clusters varied significantly by gender, race/ethnicity, educational attainment, and drug use characteristics. In addition, perceptions and behaviors initiated to reduce the chances of becoming infected with HIV varied by cluster. Subjects in the crack-predominant clusters reported low perceptions of the chances of getting AIDS. Perceptions of the chances of becoming infected with HIV among subjects in the injection-predominant clusters were strongly related to injection frequency. Seroprevalence was also related to cluster. Higher rates of HIV infection were evident among the injection-predominant clusters, and higher rates were related to frequency of injection and the rate of risky needle use. Among the crack-predominant clusters, the relationship between drug use and sexual behaviors and HIV infection was less clear.

Broadband square-pulse operation of a passively mode-locked fiber laser for fiber Bragg grating interrogation

A long-cavity, passively mode-locked erbium fiber laser operated in the square-pulse regime is demonstrated as a useful light source for interrogating fiber Bragg grating arrays. Output pulses with 4-W peak-power, 10-ns pulse widths, and bandwidths greater than 60nm were used successfully to interrogate 2% fiber Bragg gratings.

Grating sensor array demodulation by use of a passively mode-locked fiber laser

A fiber Bragg grating sensor array is interrogated by use of a passively mode-locked fiber laser source. A novel demodulation scheme that uses highly dispersive fiber to convert the grating wavelength shift to a temporal shift in the arrival time of the reflected pulses is demonstrated. The source bandwidth of >85 nm permits interrogation of many-grating arrays, and the demodulation technique permits fast sensing of large strains.

Nonlinear-optical loop mirror demultiplexer using a random birefringence fiber: comparisons between simulations and experiments

A numerical simulation of the switching characteristics of a polarization multiplexed nonlinear-optical loop mirror demultiplexer is presented and compared with experiment. The model assumes that the optical fiber that composes the loop has a randomly varying birefringence, that the signal and the control pulses have the same frequency, and that these pulses are nearly solitons. Factors that affect the shape and the width of the switching window curve are discussed. A phase-dependent modulation of the switching window curve, which is due to incomplete averaging of the light polarization state, is observed both experimentally and numerically. Models in which the randomness is neglected are not able to describe this modulation adequately.

Third-order dispersion in femtosecond fiber lasers

We experimentally investigate the effects of third-order dispersion (TOD) on ultrafast sources, using dispersion-compensated femtosecond fiber lasers. By in situ measurement of the intracavity dispersion, we identify spectral resonances that are due to coupling of the cavity pulse energy to dispersive wave components at the phase velocity and group-velocity-matched wavelengths. We obtain pulse widths as short as 91 fs by partially compensating the TOD. We relate the observed effects to consequences for soliton transmission and operation of other solitary-pulse lasers.

Effectiveness of streamlined admissions to methadone treatment: a simplified time-series analysis

Increasing the availability of, and streamlining the admissions process to, methadone treatment have consistently been the focus of national plans to address the acquired immune deficiency syndrome (AIDS) epidemic. This article uses simplified time-series analysis to evaluate one of the first methadone treatment Waiting List Reduction Demonstration Grants. The demonstration grant significantly increased both the number of people requesting intake appointments from 35 to 100 per month and the percentage of kept appointments from 33% to 54%. An additional 100 slots (an entire year's waiting list) were filled in fewer than three months and actually resulted in a net increase in the length of the waiting list. Relative to the preceding two years, new clients during the grant period were significantly more likely to be 41 or older, African-American, unemployed, daily opioid users, daily cocaine users, and dependent on public assistance to finance treatment. Controlling for the source of treatment financing (a case-mix adjustment), there were no significant changes in retention rates. The program's static client capacity rose from 310 prior to the grant to a peak of 449 during the grant, with a leveling to 410 after the grant. Given that it is clearly more humane and less expensive to treat people who want treatment rather than wait for them to commit a crime and be arrested or even executed, this study strongly suggests the need to make more treatment available on demand.

Gender differences in vocational needs and outcomes for methadone treatment clients

Data from a pilot randomized field experiment conducted from 1990 to 1992 in three methadone treatment programs were analyzed to examine potential gender differences in vocational needs and outcomes. The study data were collected from 103 female and 147 male clients who were recommended by their counselors or were randomly sampled from all remaining clients enrolled in treatment. Half of each of these two groups of clients were randomly assigned to standard treatment and half to standard treatment plus an experimental Training and Employment Program (TEP). Analysis of the data indicates that (a) males and females differed significantly in terms of initial employment histories, employment status, and vocational readiness; (b) males received an equal amount or more TEP services than females from an on-site vocational specialist; and (c) within the TEP condition at three months, males received more referrals and placement services than did females. These results suggest that males and females have different vocational service needs and outcomes.

Analysis of a ring-laser gyroscope with intracavity phase-conjugate coupling

A ring-laser gyroscope with the opposite modes coupled by an intracavity phase-conjugate interaction is examined analytically and numerically. It is shown that the coupling mitigates cross-saturation-induced mode extinction, allowing a homogeneously broadened medium to be used as the gain for a laser gyroscope. It is also shown that the coupling can induce a bias beat frequency that can potentially be used as an all-optical dither. The phase conjugation is shown to affect the lock-in threshold only indirectly. The results are compared with pertinent experiments from the literature.

Training and employment programs in methadone treatment: client needs and desires

Training and employment programs (TEP) in methadone treatment have declined in recent years. Yet heroin abusers who enter methadone treatment have historically high unemployment and low earnings compared to the general population and other treatment modalities. This paper reports on the first phase of a multiyear project to develop and evaluate TEPs for methadone treatment clients. Preliminary findings from the treatment intake survey of the pilot study are used to identify client needs and desires. Specifically, we report descriptive statistics for clients' (a) demographics, (b) education and training, (c) employment status, (d) income and expenditures, (e) interest in a TEP, and (f) labor market expectations thereafter. We conclude with a presentation of our proposed future analyses and a discussion of the policy implications of the project. Our main finding is that most addicts have a strong interest in training and employment services, but their expectations about the impact of such services is often unrealistic.

Femtosecond ring dye laser: a potential new laser gyro

Measurements on a passively mode-locked dye laser demonstrate a sensitive gyro-type response, when Fresnel drag in air is used to simulate rotation. Such a response is unexpected for a homogeneously broadened ring laser.

Cocaine use by clients in methadone programs: significance, scope, and behavioral interventions

Widespread use of cocaine by methadone clients is undermining the effectiveness of methadone treatment programs in reducing illicit drug use, decreasing criminal behavior, and slowing the spread of the human immunodeficiency virus (HIV). In response, methadone programs are implementing a range of behavioral interventions to manage this growing problem. Many of these interventions, however, have yet to be evaluated for effectiveness for reducing cocaine use among methadone clients. Interventions that are effective for cocaine use in the general population may not be as effective with cocaine users in methadone programs because these clients differ from other cocaine users in ways that are likely to affect how they respond to the interventions. This paper reviews the literature on the significance and scope of the problem of cocaine use by methadone clients and on the behavioral interventions that have been evaluated for these clients.