Characteristics of coexisting attractors and ghost orbiting in an optomechanical microresonator

We explore the nonlinear interactions of an optomechanical microresonator driven by two external optical signals. Optical whispering-gallery waves are coupled to acoustic surface waves of a fused silica medium in the equatorial plane of a generic microresonator. The system exhibits coexisting attractors whose behaviors include limit cycles, steady states, tori, quasi-chaos, and fully developed chaos with ghost orbits of a known attractor. Bifurcation diagrams demonstrate the existence of self-similarity, periodic windows, and coexisting attractors and show high-density lines within chaos that suggests a potential ghost orbit. In addition, the Lyapunov spectral components as a function of control parameter illuminate the dynamic nature of attractors and periodic windows with symmetric and asymmetric formations, their domains of existence, their bifurcations, and other nonlinear effects. We show that the power-shift method can access accurately and efficiently attractors in the optomechanical system as it does in other nonlinear systems. To test whether the ghost orbit is the link between two attractors interrupted by chaos, we examine the elements of the bifurcation diagrams as a function of control parameter. We also use detuning as a second control parameter to avoid the chaotic region and clarify that the two attractors are one.

A Diagnostic Dilemma: Atypical Systemic Pyoderma Gangrenosum

Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis that classically presents with chronic ulcerations with raised, violaceous, and undermined borders commonly found on the lower extremities. Less common presentations include tender nodules, pustules, or bullae that may occur on other sites of the body. In rarer circumstances, PG can lead to a systemic inflammatory response syndrome with extensive pulmonary infiltrates but ultimately cause and etiology of the disease are still uncertain. Unfortunately, there is no laboratory test or histopathologic finding that is specific to PG, which makes the diagnosis even more elusive.

Malignant myopericytoma: Case report and review of the literature

A 29-year-old male presented with a two-week history of a tender lesion on his right thigh. The lesion was a 1.5 cm erythematous nodule with overlying hemorrhagic crust. Histopathologic examination of a biopsy specimen revealed a highly cellular neoplasm with irregular vesicular nuclei, prominent nucleoli, and scattered mitotic figures. The cells within the lesion were rounded, ovoid and spindle shaped cells with perivascular growth. The architecture and staining pattern of the lesion were most consistent with a diagnosis of malignant myopericytoma, an exceedingly rare malignancy.

Predicting attractor characteristics using Lyapunov exponents in a laser with injected signal

Coexisting attractors are studied in a single-mode coherent model of a laser with an injected signal. We report that every attractor has a unique Lyapunov exponent (LE) pattern that is choreographed by the subtle variations in the attractor's dynamics and circumscribed by a common Lyapunov spectral pattern that begins and ends with two-zero LEs. Lyapunov spectra form symmetric-like and asymmetric bubbles; the former foreshadows an attractor's proximity to the cusp of an eminent change in dynamics and the latter indicates the presence of a bifurcation. We show that the peak values of the asymmetric bubbles are always associated with two-zero LEs; in fact, they are allied inseparably in forecasting period-doubling episodes. The two-zero LEs' predictor of torus dynamics is refined to include the convergence of three LEs to a triplet of zeros as a precursor to the two-zero spectra. We report that the long-standing two-zero LEs' signature is a necessary but not sufficient condition for predicting attractors and their dynamic conditions. The evolution of the attractor volume as a function of the injected signal is compared to the spectral formation of the attractor; we report slope changes and points of inflections in the volume trajectory where spectral changes indicate dynamic changes. Attractor viability is tested preliminarily by including random low-level noise in the frequency of the injected signal.

Near-Sun observations of an F-corona decrease and K-corona fine structure

Remote observations of the solar photospheric light scattered by electrons (the K-corona) and dust (the F-corona or zodiacal light) have been made from the ground during eclipses¹ and from space at distances as small as 0.3 astronomical units^2-5 to the Sun. Previous observations^6-8 of dust scattering have not confirmed the existence of the theoretically predicted dust-free zone near the Sun^9-11. The transient nature of the corona has been well characterized for large events, but questions still remain (for example, about the initiation of the corona¹² and the production of solar energetic particles¹³) and for small events even its structure is uncertain¹⁴. Here we report imaging of the solar corona¹⁵ during the first two perihelion passes (0.16-0.25 astronomical units) of the Parker Solar Probe spacecraft¹³, each lasting ten days. The view from these distances is qualitatively similar to the historical views from ground and space, but there are some notable differences. At short elongations, we observe a decrease in the intensity of the F-coronal intensity, which is suggestive of the long-sought dust free zone^9-11. We also resolve the fine-scale plasma structure of very small eruptions, which are frequently ejected from the Sun. These take two forms: the frequently observed magnetic flux ropes^12,16 and the predicted, but not yet observed, magnetic islands^17,18 arising from the tearing-mode instability in the current sheet. Our observations of the coronal streamer evolution confirm the large-scale topology of the solar corona, but also reveal that, as recently predicted¹⁹, streamers are composed of yet smaller substreamers channelling continual density fluctuations at all visible scales.

Vitamin C Supplementation, APOE4 Genotype and Cognitive Functioning in a Rural-Dwelling Cohort

OBJECTIVE

Apolipoprotein E4 (APOE4) genotype has been implicated as a moderating factor in cognitive function studies. Although prior studies have suggested that vitamin C is associated with better cognitive function in elders, link between the two has been mixed. Limited data exist as to whether the APOE4 genotype influences these associations. Therefore, this study sought to determine whether the association between vitamin C and cognition in a rural community dwelling cohort differs by the APOE4 genotype.

DESIGN AND PARTICIPANTS

Data were analyzed on 582 participants (n=183 men; n=399 women) from a rural community-based cohort. Cognition was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status and The Executive Interview. APOE genotyping was ascertained by standard methods. The relation between vitamin C supplementation and cognition were analyzed first with ANOVA and then ANCOVA with age, gender, education as covariates. Analyses were initially run in the full sample and then split by APOE4 presence (yes/no).

RESULTS

Overall, Vitamin C supplementation was associated with significantly better immediate memory (p=0.04), visuospatial skills (p=0.002), language (p=0.01), and global cognitive functioning (p=0.006). Among APOE4 non-carriers, vitamin C supplementation was positively associated with immediate memory (F[1,392] =6.7, p=0.01), visuospatial skills (F[1,391]=10.6, p=0.001), language (F[1,392]=13.0, p<0.001), attention (F[1,386]=7.9, p=0.005, and global cognition (F[1,382]=11.0, p=0.001. However, there was no significant link between vitamin C supplementation and cognition among APOE4 carriers.

CONCLUSION

Vitamin C supplementation was found to be positively associated with cognition among this rural-dwelling community-based sample; however, the associations appeared to differ by APOE4 status. These data may suggest that targeted genotype-specific cognitive enhancement studies are needed to clarify the potential benefits of vitamin C supplementation.

Differentiating psychopathy from antisocial personality disorder: a triarchic model perspective

BACKGROUND

The triarchic model of psychopathy characterizes the disorder in terms of three distinguishable phenotypic facets: disinhibition, meanness and boldness. The present study sought to (1) inform current debates regarding the role of boldness in the definition of psychopathy and (2) clarify boundaries between psychopathy and antisocial personality disorder (ASPD).

METHOD

This study evaluated the degree to which facets of the triarchic model are represented in the most widely used clinical inventory for psychopathy, the Psychopathy Checklist - Revised (PCL-R), in comparison with ASPD as defined by DSM-IV criteria. Adult male offenders from two distinct correctional settings (n = 157 and 169) were investigated to ensure replicability of findings across samples exhibiting high base rates of psychopathy and antisocial behavior.

RESULTS

We found evidence for convergent and discriminant validity of the three triarchic facets in predicting symptomatic components of psychopathy as assessed by the PCL-R. Additionally, and crucially vis-à-vis current debates in the field, we found that boldness contributed incrementally (over and above disinhibition and meanness) to prediction of PCL-R psychopathy, in particular its interpersonal style component, but not ASPD.

CONCLUSIONS

The three distinct facets of the triarchic model of psychopathy are represented clearly and distinctly in the PCL-R, with boldness through its interpersonal facet, but not in DSM-defined ASPD. Our findings suggest that boldness is central to diagnostic conceptions of psychopathy and distinguishes psychopathy from the more prevalent diagnosis of ASPD.

Long-term mercury dynamics in UK soils

A model assuming first-order losses by evasion and leaching was used to evaluate Hg dynamics in UK soils since 1850. Temporal deposition patterns of Hg were constructed from literature information. Inverse modelling indicated that 30% of 898 rural sites receive Hg only from the global circulation, while in 51% of cases local deposition exceeds global. Average estimated deposition is 16 μg Hg m(-2) a(-1) to rural soils, 19 μg Hg m(-2) a(-1) to rural and non-rural soils combined. UK soils currently hold 2490 tonnes of reactive Hg, of which 2140 tonnes are due to anthropogenic deposition, mostly local in origin. Topsoil currently releases 5.1 tonnes of Hg(0) per annum to the atmosphere, about 50% more than the anthropogenic flux. Sorptive retention of Hg in the lower soil exerts a strong control on surface water Hg concentrations. Following decreases in inputs, soil Hg concentrations are predicted to decline over hundreds of years.

Mercury in United Kingdom topsoils; concentrations, pools, and Critical Limit exceedances

The median total mercury concentration in 898 UK rural topsoils, sampled between 1998 and 2008, was 0.095 μg g(-1). Approximate adjustment for unreactive metal produced an estimate of 0.052 μg g(-1) for reactive Hg. The highest concentrations were in the north and west, where organic-rich soils with low bulk densities dominate, but the spatial pattern was quite different if soil Hg pools (mg m(-2)) were considered, the highest values being near to the industrial north of England and London. Possible toxic effects of Hg were best evaluated by comparison with soil Critical Limits expressed as ratios of Hg to soil organic matter, or soil solution Hg(2+) concentrations, estimated by chemical speciation modelling. Only a few percent of the rural UK soils showed exceedance, and this also applied to rural soils from the whole of Europe. UK urban and industrial soils had higher Hg concentrations and more cases of exceedance.

The immune and stress responses of Atlantic cod to long-term increases in water temperature

Sea-caged cod are limited in their movements in the water column, and thus can be exposed to large seasonal ( approximately 0-20 degrees C) temperature fluctuations. To investigate the physiological response of Atlantic cod to summer-like increases in temperature, we exposed 10 degrees C acclimated juvenile cod to a graded thermal challenge (1 degrees C increase every 5 days) and measured: (1) plasma cortisol and glucose levels; (2) the respiratory burst activity of blood leukocytes; and (3) the expression of specific immune-related genes [MHC Class I, Interleukin-1beta (IL-1beta), beta2-microglobulin (beta2-M), Immunoglobulin M (IgM)-light (L) and -heavy (H) chains] in the blood using quantitative reverse transcription-polymerase chain reaction (QRT-PCR). The experiment was stopped at 19.1 degrees C, with 26.7% of the fish surviving to this point. Plasma glucose levels increased slightly at 16 and 18 degrees C (by 1.39- and 1.74-fold, respectively), in contrast, cortisol levels were elevated significantly (by 2.9-fold) at 16 degrees C but returned to control levels thereafter. The effect of increasing temperature on the expression of immune related genes in blood cells (leukocytes) was variable and depended on the gene of interest. The expression of IgM-H remained stable for the duration of the experiment. In contrast, IL-1beta expression was increased significantly (by approximately 25-fold) at 19 degrees C as compared to time-matched control fish, and changes in the expression of beta2-M, MHC Class I and IgM-L followed a pattern similar to that seen for cortisol: increasing at 16 degrees C (by 4.2-, 5.3- and 17-fold, respectively), but returning to pre-stress levels by 19 degrees C. Interestingly, increasing temperatures had no effect on respiratory burst activity. This study is the first to examine the effects of a chronic regimen of increasing temperature on the stress physiology and immunology of a marine teleost, and suggests that immune function is influenced by complex interactions between thermal effects and temperature-induced stress (elevated circulating cortisol levels).

Long-term nitrate increases in two oligotrophic lakes, due to the leaching of atmospherically-deposited N from moorland ranker soils

During the last 50 years nitrate concentrations in Buttermere and Wastwater (Cumbria, UK) have risen significantly, by 70 and 100%, respectively. By estimating contemporary nitrate fluxes in the lakes' catchments and in sub-catchments and comparing them with the fractional areas of different soil types, it is deduced that the surface water nitrate is derived almost entirely from organic-rich ranker soils that have a limited ability to retain atmospherically-deposited nitrogen. Little or no nitrate leaches from the other major soil type, a brown podzol, despite it having a lower C:N ratio (12.0 g g(-1)) than the ranker (17.0 g g(-1)), nor is there much contribution from the small areas of improved (chemically fertilised) grassland within the catchments. Although some nitrate leaching is occurring, total N losses are appreciably smaller than atmospheric inputs, so the catchment soils are currently accumulating between 3 and 4 g N m(-2) a(-1).

Estimating uncertainty in terrestrial critical loads and their exceedances at four sites in the UK

Critical loads are the basis for policies controlling emissions of acidic substances in Europe and elsewhere. They are assessed by several elaborate and ingenious models, each of which requires many parameters, and have to be applied on a spatially-distributed basis. Often the values of the input parameters are poorly known, calling into question the validity of the calculated critical loads. This paper attempts to quantify the uncertainty in the critical loads due to this "parameter uncertainty", using examples from the UK. Models used for calculating critical loads for deposition of acidity and nitrogen in forest and heathland ecosystems were tested at four contrasting sites. Uncertainty was assessed by Monte Carlo methods. Each input parameter or variable was assigned a value, range and distribution in an objective a fashion as possible. Each model was run 5000 times at each site using parameters sampled from these input distributions. Output distributions of various critical load parameters were calculated. The results were surprising. Confidence limits of the calculated critical loads were typically considerably narrower than those of most of the input parameters. This may be due to a "compensation of errors" mechanism. The range of possible critical load values at a given site is however rather wide, and the tails of the distributions are typically long. The deposition reductions required for a high level of confidence that the critical load is not exceeded are thus likely to be large. The implication for pollutant regulation is that requiring a high probability of non-exceedance is likely to carry high costs. The relative contribution of the input variables to critical load uncertainty varied from site to site: any input variable could be important, and thus it was not possible to identify variables as likely targets for research into narrowing uncertainties. Sites where a number of good measurements of input parameters were available had lower uncertainties, so use of in situ measurement could be a valuable way of reducing critical load uncertainty at particularly valuable or disputed sites. From a restricted number of samples, uncertainties in heathland critical loads appear comparable to those of coniferous forest, and nutrient nitrogen critical loads to those of acidity. It was important to include correlations between input variables in the Monte Carlo analysis, but choice of statistical distribution type was of lesser importance. Overall, the analysis provided objective support for the continued use of critical loads in policy development.

Understanding factors that influence smoking uptake

OBJECTIVE

To explore relationships between patterns of smoking uptake and social context and attitudinal variables.

DESIGN

Cross sectional survey.

SETTING

Public schools in Tucson, Arizona and Albuquerque, New Mexico.

PARTICIPANTS

982 children in grades 6-9 (ages 11-15 years).

MAIN OUTCOME MEASURES

Items measuring smoking history, nicotine dependence and quit attempts, susceptibility to smoking in the future, smoking norms, use of other tobacco products, attitudes toward smoking, and demographic characteristics.

RESULTS

Overall, 43% of children had smoked a cigarette and 57% had never used them. Ever smokers lived in social contexts with more smoking and where smoking was normative. Among never users, 25% are susceptible to smoking; these children have positive attitudes toward smoking, do not feel social pressure to stay off cigarettes, and had more friends who smoked. Among ever users, 36% were currently smoking in the past 30 days. Current users also lived in social context with more smoking and had positive attitudes toward smoking. Most users had tried to stop smoking. Only 9% of current users smoked daily; 29% had not smoked a whole cigarette. Greater cigarette consumption was associated with more favourable attitudes toward smoking. Most of past users were in early uptake: 95% had smoked less than 100 cigarettes but 49% were susceptible to smoking again.

CONCLUSIONS

There is promise in differentiating subgroups among the never, past and current use of cigarettes. Susceptibility within each of these groups was associated with similar patterns of attitudes and social context. These patterns in smoking uptake need to be confirmed prospectively.

Bilateral tibia and fibula fractures in a patient with rheumatoid arthritis

A 52-year-old woman with rheumatoid arthritis treated with low-dose steroids developed bilateral distal tibia and fibula fractures over a 15-month period. Her bone density was within osteopenic levels. Such fractures are an unusual but increasingly recognised complication of rheumatoid disease and its treatment, although there is often diagnostic delay. Bilateral fractures are particularly rare. A high level of clinical suspicion is required for early diagnosis.

Effect of emissions control programs on visibility in southern California

A new method for the analysis and display of the effect of emissions controls on visibility is applied to conditions in southern California. An advanced mechanistic air quality model that represents airborne particles as a source-oriented external mixture first is used to track emissions source contributions to the size distribution and chemical composition of airborne particles at Claremont, CA, under heavy smog conditions. The resulting description of the aerosol is used in a Mie scattering calculation to determine the magnitude and particle size dependence of light scattering and absorption in the atmosphere. The resulting light scattering and absorption coefficient values are supplied to an image processing-based visibility model that creates full color representations of the appearance of the local terrain in the presence of the specified level of air pollution based on satellite-generated landscape images. By linking these models, a direct connection is established between source emissions and resulting visual air quality. The composite modeling system then is used to studythe effectthat different emissions control strategies would have on visibility in southern California. An aggressive program of 92 specific emissions control measures that include primary particle controls plus controls on reactive gases that act as secondary aerosol precursors would more than double visual range at Claremont under the 1987 historical conditions studied. Synthetic landscape images show that the mountains to the north of Claremont that are not visible at a range of 10 km under base-case conditions would be visible if the emissions controls described above were applied.

Disease-associated mutations in SOD1 are impervious to dominant positive or negative effects

The familial form of amyotrophic lateral sclerosis is caused by mutations in the SOD1 gene encoding the cytosolic antioxidant enzyme Cu,Zn superoxide dismutase. Although there is no clear correlation between disease and dismutating catalytic activity among the various disease-associated SOD1 alleles, all of the known missense mutations significantly alter the half-life of the encoded polypeptides. Using transient transfection studies in mammalian cells, it was demonstrated that a frameshift mutation in SOD1 which results in a truncated polypeptide is similarly destabilized. Using an epitope-tagging strategy to discriminate between mutant and wild-type SOD1 polypeptides, no evidence for dominant effects on polypeptide stability was detected, including that of a positive effect of the wild-type on mutant SOD1 polypeptides or that of a negative effect of mutant on wild-type SOD1 polypeptides. These experiments thus favor a non-catalytic role of mutant forms of SOD1 in disease progression.

Using language intensity to increase the success of a family intervention to protect children from ultraviolet radiation: predictions from language expectancy theory

BACKGROUND

Even though people are informed about skin cancer prevention, they do not always comply with prevention advice. From Language Expectancy Theory, it was predicted that messages with high language intensity would improve compliance with sun safety recommendations and that this effect would be enhanced with deductive argument style.

METHODS

Parents (N = 841) from a pediatric clinic and elementary schools received sun safety messages (newsletters, brochures, tip cards) by mail that varied in language intensity and logical style. Effects on attitudes and behavior were tested in a pretest-posttest factorial design.

RESULTS

As hypothesized, parents receiving messages with high- as opposed to low-intensity language complied more with sun safety advice. Messages with highly intense language were more persuasive when the arguments were formatted in a deductive style; low language intensity was more persuasive in inductively styled messages.

CONCLUSIONS

By carefully adjusting messages features, health professionals can obtain further compliance beyond that produced by educating people about health risks and creating favorable attitudes and self-efficacy expectations. Highly intense language may be a good general strategy in prevention messages and works better when conclusions and recommendations are offered explicitly to recipients, especially when advice is aimed at reducing their personal risk.

Long-term effects of language intensity in preventive messages on planned family solar protection

A series of sun safety messages containing highly intense language and deductive logical style achieved the most immediate compliance by parents, particularly when they intended to improve protection. Inductive messages were more successful when no intentions existed (D. B. Buller, Borland, & Burgoon, 1998; D. B. Buller et al., 2000). Interviewers recontacted 568 parents during the winter following message dissemination and assessed solar protection. A 2 (language intensity) x 2 (logical style) x 3 (behavioral intention) x 2 (person) mixed-model analysis of variance showed that parents receiving high-intensity, deductive messages reported the most improved solar protection and improvement was greatest when parents intended to improve protection. Over the long term, high language intensity may reinforce decisions to take preventive action and does not appear to provoke psychological reactance or resistance to these highly directive messages.

Grandpaternal mosaicism in a family with isolated haemophilia A

About one third of cases of haemophilia A have no family history of the disorder, and 20% are thought to be due to a new mutation. In the family reported here, a 3 bp deletion was detected in DNA from the proband at the 3' end of exon 15. Direct sequencing of genomic DNA prepared from blood and buccal cells of the grandfather revealed both normal and mutant sequences, suggesting that he is a mosaic for this mutation. This highlights the usefulness of mutation detection, both for accurate genetic counselling and to determine the origin of new mutations of haemophilia.

Evaluation of the "Sunny Days, Healthy Ways" sun safety CD-ROM program for children in grades 4 and 5

Computer-based sun safety instruction has many advantages that may be attractive to health educators in schools. An educational multimedia computer program on sun safety was produced on CD-ROM for children in grades 4 and 5, which was based on the "Sunny Days, Healthy Ways" sun safety curriculum (SDHW). Its effects on children's sun safety knowledge, attitudes and behaviour were evaluated with 162 students in 8 fourth and fifth grade classes in a randomized pretest-posttest 2 x 2 factorial design. Children interacting with the CD-ROM program showed significant improvements in knowledge (p = 0.007). The effect on knowledge may have indirectly improved children's sun protection (r = 0.201, p = 0.013), even though the CD-ROM program did not directly increase sun protection (p > .05) or improve attitudes (p > .05). The CD-ROM program may be a cost-effective and administratively acceptable sun safety instructional strategy, however, like many short prevention strategies, it will be most successful at conveying information on sun safety to children.

Efficient control of tetracycline-responsive gene expression from an autoregulated bi-directional expression vector

The tetracycline-responsive expression system is based on the ability of the chimeric tTA and rtTA transactivators to stimulate specifically transcription from a companion synthetic CMV* or TK* promoter element, and can provide tightly regulated gene expression that can be induced up to five orders of magnitude in cultured cells and transgenic mice. A major problem with the system is that high level expression of the tTA or rtTA transactivators causes cellular toxicity. Under conditions of prolonged expression this results in selective pressure against the stable incorporation of vectors expressing the tTA or rtTA transactivators, and makes the generation of stable cell lines and transgenic mice problematic. In this report we describe the development of a set of autoregulated bi-directional expression vectors in which the weaker TK* promoter is used to direct expression of the rtTA or tTA transactivator and the stronger CMV* element is used to direct cDNA expression. In this format the transactivator and response elements are encoded on the same vector, which simplifies the system and ensures that gene expression is effectively skewed in favor of the cDNA while maintaining a continuously low level of transactivator expression. We find that such an autoregulated system works equally well for both the tTA and rtTA transactivators, provided that they contain a nuclear localization signal. Similar to other versions of the tetracycline-responsive expression system, gene expression is tightly regulated and can be efficiently switched between the off and on expression states by doxycycline. In contrast with other tetracycline-responsive systems, however, expression of the rtTA and tTA transactivators from the autoregulated TK* promoter is low enough such that there is no cellular toxicity associated with either expression state. By incorporating a selectable marker into these vectors, all of the components required for using the system are now contained on a single plasmid construct, and we find that this format provides a more reliable and greatly simplified method for the generation of stable cell lines.

The clinical and radiological features of cholecystocolic fistulae

The clinical and radiological features of seven patients presenting with cholecystocolic fistulae are reviewed. The majority of the patients were elderly (age range 43-85 years, mean 70.7 years) and there was a female preponderance (6:1). The condition usually has a benign clinical course. Diarrhoea was the most common presenting symptom and the typical clinical features of gallbladder disease were absent. Cholangitis occurred in only one patient. The time between onset of symptoms and diagnosis varied from 1 week to 2 years (mean 22 weeks). In only one patient was the diagnosis of biliary-intestinal fistula suspected on the basis of the plain abdominal radiograph (Case 5). A diagnosis of cholecystocolic fistula was established by barium enema (5 cases), endoscopic retrograde cholangiopancreatography (ERCP) (1 case) and diagnostic laparotomy (1 case). The only cause identified in this series was acute or chronic cholecystitis.

The outcome for children with blunt trauma is best at a pediatric trauma center

PURPOSE

The mortality rate for pediatric trauma patients cared for in adult trauma centers has been shown, by means of TRISS methodology, not to differ significantly from that of the Major Trauma Outcome Study (MTOS). The question remains, however, whether the outcome of injured children is better in a designated pediatric trauma center (DPTC). The authors' hypothesis is that outcome is better at a DPTC.

METHODS

The records of 1,797 children (0 to 15 years of age) admitted to a DPTC between 1987 and 1993 were reviewed. TRISS methodology was used to calculate probability of survival for outcome comparison with the MTOS. The data also was compared with outcome in relation to the admitting Glasgow Coma Score (GCS) reported in the National Pediatric Trauma Registry (NPTR).

RESULTS

The outcome of all children at this DPTC had a Z score of +1.4199 (P > .1). The Z score of children admitted because of penetrating trauma (PT, n = 460) did not differ significantly from that of the MTOS. However, the children admitted because of blunt trauma (BT, n = 1,337) had a Z score of +3.3501 (M score = .90), which is significantly better than that of the MTOS (P < .001). The BT population with an ISS of > or = 9 (n = 149) had a Z score of +2.8686 (P < .005) (M = .95). By GCS comparison, the BT group had a outcome similar to that reported in the NPTR. Head injury was the cause of death for 26 (84%) of the 31 PT deaths and 20 (83%) of the 24 BT deaths (three of the remaining four had associated severe head injury). Only 1 of 24 (4%) BT liver injuries and 5 (21%) of 24 BT splenic injuries required surgical intervention. This low incidence of liver and splenic surgical invention is similar to that reported by other DPTCs, but for children treated at adult centers the rates are 37% to 58% and 43% to 53% for liver & splenic surgical intervention, respectively.

CONCLUSION

Children with BT have a significantly better outcome at a DPTC; the outcome for children with PT does not differ. Successful nonoperative treatment of blunt abdominal injuries is more likely to occur at a DPTC than at adult trauma centers "with pediatric committment." Thus, children with blunt injuries should be taken to a DPTC, when available.

Drainage following radical hysterectomy and pelvic lymphadenectomy: dogma or need?

OBJECTIVE

To compare the incidence of lymphocyst formation and postoperative morbidity in patients drained or not drained following radical hysterectomy and pelvic lymph node dissection for cervical or endometrial malignancy.

METHODS

A prospective study was undertaken of consecutive patients undergoing radical hysterectomy and pelvic lymphadenectomy at the Regional Department of Gynaecological Oncology, Gateshead, United Kingdom, between February 1992 and September 1994. A Piver type II procedure was performed with nonclosure of the vaginal cuff and pelvic peritoneum. Patients were randomized at the end of surgery to have either two suction drains inserted along the pelvic sidewalls or to have no drains inserted. The detection of lymphocysts was made by clinical examination and abdominal ultrasound scan performed 8 weeks postoperatively.

RESULTS

Eight patients were excluded from the study when drains were deemed necessary to assess postoperative blood loss. Fifty-one were randomized to drains, and 49 to no drains. The detection of lymphocysts by ultrasound and clinical examination in the drained group (15.6 and 5.9%, respectively) was not significantly different from the group not drained (17.4 and 6.1%, respectively). There was no difference in postoperative morbidity in the two groups.

CONCLUSION

There appears to be no advantage to the routine use of pelvic suction drainage following radical hysterectomy and pelvic lymphadenectomy.

Parotid duct stenosis: interventional radiology to the rescue

Recurrent parotid sialadenitis due to isolated parotid duct stenosis is an uncommon condition and poses a difficult management problem. Conventional surgical practice carries with it a potentially high morbidity for what is a benign condition. We present three cases where parotid duct stenosis has been treated by balloon dilatation and propose that this is a safe, quick and repeatable method for dealing with this problem.

The new epidemic in children: penetrating injuries

OBJECTIVE

It is our hypothesis that there has been a dramatic increase in penetrating injuries in children. The purpose of this study is to verify this "new" epidemic in children and to note some of its characteristics.

METHODS

We performed a 7-year retrospective review of the trauma registry at our urban pediatric (< 16 years of age) trauma center (UPTC).

RESULTS

The percentage of admissions due to penetrating injuries at our UPTC has gradually risen over the past 7 years primarily due to gunshot wounds. In 1992 and 1993, compared to 1987 and 1988, the incidence of penetrating injuries has increased from 20 to 36% in all children and from 45 to 66% in the 12-to-15-year-old age group.

CONCLUSION

Injuries due to penetrating trauma have, indeed, increased to epidemic proportions.

The sensitivity of surface waters of Great Britain to acidification predicted from catchment characteristics

Using a combination of soil, land use and geological information, a map of Great Britain has been derived which indicates the sensitivity of surface waters to acidification. For the geological information, a slightly modified version of an available map was used which indicated the sensitivity of groundwaters to acidification. For soils, 1-km databases of soil information for England and Wales and for Scotland were employed to map the soil sensitivity as determined by buffering capacity. The derived soils map was modified to take account of agricultural liming in arable and managed grassland areas using the ITE Land Classification. The final map of surface water sensitivity was obtained by using a geographic information system overlay procedure which enabled each combination of soil and geology sensitivity to be uniquely defined. The final sensitivity classification was based upon expert knowledge and the experience of a similar sensitivity mapping exercise for Wales.

The U.S. experience with smoke detectors: who has them? How well do they work? When don't they work?

From 1975 to 1984, the United States experienced remarkable growth in the use of home smoke detectors, making the home smoke detector the fire safety success story of the decade. As of 1993, only 1 home in 12 remained unprotected.

Preparation of the colon for double-contrast barium enema: comparison of Picolax, Picolax with cleansing enema and Citramag (2 sachets)--a randomized prospective trial

A randomized prospective trial was undertaken on 196 consecutive patients referred for double-contrast barium enema examination to assess the relative efficacy of three colon cleansing regimes: Citramag (2 sachets), Picolax and Picolax with a preliminary cleansing enema. Each of the regimes was preceded by a 5 day low residue diet. The radiographs from the examinations were assessed on a double-blind basis. The quality of bowel preparation was significantly poorer (P < 0.001) in the group receiving the preliminary cleansing enema, notably with respect to mucosal coating, compared with the other two groups. The quality of the preparation was slightly better in the group receiving Picolax alone than in the Citramag group (P < 0.01), the difference being most apparent in the proximal colon. The laxatives were equally well tolerated. The study has formed the basis of a departmental audit. As a result, the bowel preparation has been standardized to a 5 day period of dietary restriction followed by 2 Picolax sachets. This measure has improved efficiency within the department with no sacrifice in quality.

Insulin gene region-encoded susceptibility to type 1 diabetes is not restricted to HLA-DR4-positive individuals

Type 1 or insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease of the insulin-producing pancreatic beta-cells which is determined by both genetic and environmental factors. The major histocompatibility complex and the insulin gene region (INS) on human chromosomes 6p and 11p, respectively, contain susceptibility genes. Using a mostly French data set, evidence for linkage of INS to IDDM was recently obtained but only in male meioses (suggesting involvement of maternal imprinting) and only in HLA-DR4-positive diabetics. In contrast, we find evidence for linkage in both male and female meioses and that the effect of the susceptibility gene(s) in the INS region is not dependent on the presence of HLA-DR4.

Blood contamination of anesthesia equipment and monitoring equipment

This study was conducted to determine the extent of blood contamination of anesthesia equipment and monitoring equipment in clinical use in operating rooms. The study employed a catalytic-test method, which is used in forensic medicine, to detect blood contamination of anesthesia equipment and monitoring equipment. Nineteen definable surfaces were sampled in 22 operating rooms. Thirty-three percent of surfaces were contaminated with blood. Contaminated equipment included surfaces that are in continuous contact with patients, e.g., blood pressure cuffs and pulse oximeter probes. Visual inspection was not a reliable means of detecting blood contamination. Whether this blood contamination represents an infection risk was not determined. Nevertheless, improved cleaning and disinfection procedures are probably needed. Equipment design needs to focus on reducing the potential for blood contamination and enhancing capability for cleaning and disinfection.

U.S. high-rise fires: the big picture

In the past, efforts to track fire experience in high-rise buildings have been less than systematic. Now, for the first time, we can provide an overall perspective on the problem.

Arteriography in the evaluation of penetrating pediatric extremity injuries

The routine use of arteriography for evaluating penetrating extremity injuries is undergoing reevaluation in the adult literature. Its role in children is less clear. Eighty-seven children treated for penetrating extremity trauma over a 5-year period were studied retrospectively to define the usefulness of arteriography. The ages ranged from 2 to 16 years. Twenty-four arteriograms were performed. Twelve were for patients who exhibited physical signs of vascular injury (diminished pulse, distal ischemia, expanding hematoma, or bruits/thrills over the wound). The other 12 were performed on asymptomatic children with wounds in proximity to major vessels. Two other patients with ongoing hemorrhage were taken directly to the operating room. Of the 12 arteriograms performed for abnormal physical signs, eight (67%) showed vascular injuries. None of the studies performed for proximity alone had abnormal results (P < .01). Ten of 10 patients with vascular injuries had abnormal physical findings, whereas only four of 77 patients without vascular injuries had abnormal findings (sensitivity 100%, specificity 95%). Eighty-five percent of patients have had follow-up in the pediatric surgery clinic, and no missed injuries or complications have been discovered. Timely diagnosis and repair is the cornerstone for successful management of vascular injuries. While the arteriogram is an important adjunct in patients who have abnormal physical findings, proximity to major vessels alone fails to identify patients at risk for significant injuries. Angiography may not be warranted in patients whose physical examination results are normal. Noninvasive modalities such as B-mode ultrasound and Doppler may have future application in the evaluation of these cases.