Topsoil porosity prediction across habitats at large scales using environmental variables

Soil porosity and its reciprocal bulk density are important environmental state variables that enable modelers to represent hydraulic function and carbon storage. Biotic effects and their 'dynamic' influence on such state variables remain largely unknown for larger scales and may result in important, yet poorly quantified environmental feedbacks. Existing representation of hydraulic function is often invariant to environmental change and may be poor in some systems, particularly non-arable soils. Here we assess predictors of total porosity across two comprehensive national topsoil (0-15 cm) data sets, covering the full range of soil organic matter (SOM) and habitats (n = 1385 & n = 2570), using generalized additive mixed models and machine learning. Novel aspects of this work include the testing of metrics on aggregate size and livestock density alongside a range of different particle size distribution metrics. We demonstrate that porosity trends in Great Britain are dominated by biotic metrics, soil carbon and land use. Incorporating these variables into porosity prediction improves performance, paving the way for new dynamic calculation of porosity using surrogate measures with remote sensing, which may help improve prediction in data sparse regions of the world. Moreover, dynamic calculation of porosity could support representation of feedbacks in environmental and Earth System Models. Representing the hydrological feedbacks from changes in structural porosity also requires data and models at appropriate spatial scales to capture conditions leading to near-saturated soil conditions. Classification. Environmental Sciences.

Adjusting for Recall Bias with the Proportional Hazards Model

In studying falling frequency in the elderly, we observed that having subjects keep a diary led to a larger number of falls reported than had been noted in a previous study in the same population. The previous study asked subjects to report any falls in the previous three months. We considered two related explanations for the observation of lower incidence reports with a 3-month recall survey. First, there may have been under-reporting of falls due to recall bias. Second, the less severe falls (which did not result in injuries) may not be reported. We suggest that the proportional hazards model may be used to adjust studies in which recall is used to determine incidence and time to falls.

Internal friction of hydrated soda-lime-silicate glasses

The internal friction of hydrated soda-lime-silica glasses with total water content (C(W)) up to 1.9 wt. % was studied by dynamic mechanical analysis (DMA) using temperature-frequency sweeps from 723 K to 273 K and from 1 s(-1) to 50 s(-1). Total water content and concentrations of H2O molecules (C(H2O)) and OH groups (C(OH)) in the DMA specimens were determined by infrared spectroscopy. For low water contents (C(W) ≈ C(OH) < 0.25 wt. %) two discrete internal friction peaks below the glass transition (α relaxation) were assigned to the low-temperature motion of alkali ions (γ relaxation) and cooperative movements of dissimilar mobile species under participation of OH at higher temperature (β(OH) relaxation). For large water contents (C(W) > 1 wt. %), where significant amounts of molecular water are evident (C(H2O) > 0.15 wt. %), however, internal friction spectra change unexpectedly: the β(OH) peak heights saturate and a low temperature shoulder appears on the β-relaxation peak. This emerging relaxation mode (β(H2O) relaxation) was assigned to the motions of H2O molecules. β(H2O) relaxation was found to be faster than β(OH) but slower than γ relaxation. Activation energy of the different relaxation modes increased in the order γ < β(H2O) < β(OH) < α.

Movement of nuclei

This unit describes the first assay that reconstructs the movement of the female pronucleus in the newly fertilized frog egg. Nuclei are assembled in frog egg extracts and translocated along microtubules using the microtubule motor dynein.

Reliability of spinal palpation for diagnosis of back and neck pain: a systematic review of the literature

STUDY DESIGN

A systematic review.

OBJECTIVES

To determine the quality of the research and assess the interexaminer and intraexaminer reliability of spinal palpatory diagnostic procedures.

SUMMARY OF BACKGROUND DATA

Conflicting data have been reported over the past 35 years regarding the reliability of spinal palpatory tests.

METHODS

The authors used 13 electronic databases and manually searched the literature from January 1, 1966 to October 1, 2001. Forty-nine (6%) of 797 primary research articles met the inclusion criteria. Two blinded, independent reviewers scored each article. Consensus or a content expert reconciled discrepancies.

RESULTS

The quality scores ranged from 25 to 79/100. Subject description, study design, and presentation of results were the weakest areas. The 12 highest quality articles found pain provocation, motion, and landmark location tests to have acceptable reliability (K = 0.40 or greater), but they were not always reproducible by other examiners under similar conditions. In those that used kappa statistics, a higher percentage of the pain provocation studies (64%) demonstrated acceptable reliability, followed by motion studies (58%), landmark (33%), and soft tissue studies (0%). Regional range of motion is more reliable than segmental range of motion, and intraexaminer reliability is better than interexaminer reliability. Overall, examiners' discipline, experience level, consensus on procedure used, training just before the study, or use of symptomatic subjects do not improve reliability.

CONCLUSION

The quality of the research on interreliability and intrareliability of spinal palpatory diagnostic procedures needs to be improved. Pain provocation tests are most reliable. Soft tissue paraspinal palpatory diagnostic tests are not reliable.

S-adenosyl methionine (SAMe) versus celecoxib for the treatment of osteoarthritis symptoms: a double-blind cross-over trial. [ISRCTN36233495]

Background

S-Adenosylmethionine (SAMe) is a dietary supplement used in the management of osteoarthritis (OA) symptoms. Studies evaluating SAMe in the management of OA have been limited to Non Steroidal Anti-inflammatory Drugs (NSAIDs) for comparison. The present study compares the effectiveness of SAMe to a cyclooxygenase-2 (COX-2) inhibitor (celecoxib) for pain control, functional improvement and to decrease side effects in people with osteoarthritis of the knee.

Methods

A randomized double-blind cross-over study, comparing SAMe (1200 mg) with celecoxib (Celebrex 200 mg) for 16 weeks to reduce pain associated with OA of the knee. Sixty-one adults diagnosed with OA of the knee were enrolled and 56 completed the study. Subjects were tested for pain, functional health, mood status, isometric joint function tests, and side effects.

Results

On the first month of Phase 1, celecoxib showed significantly more reduction in pain than SAMe (p = 0.024). By the second month of Phase 1, there was no significant difference between both groups (p < 0.01). The duration of treatment and the interaction of duration with type of treatment were statistically significant (ps ≤ 0.029). On most functional health measures both groups showed a notable improvement from baseline, however no significant difference between SAMe and celecoxib was observed. Isometric joint function tests appeared to be steadily improving over the entire study period regardless of treatment.

Conclusion

SAMe has a slower onset of action but is as effective as celecoxib in the management of symptoms of knee osteoarthritis. Longer studies are needed to evaluate the long-term effectiveness of SAMe and the optimal dose to be used.

Searching biomedical databases on complementary medicine: the use of controlled vocabulary among authors, indexers and investigators

BACKGROUND

The optimal retrieval of a literature search in biomedicine depends on the appropriate use of Medical Subject Headings (MeSH), descriptors and keywords among authors and indexers. We hypothesized that authors, investigators and indexers in four biomedical databases are not consistent in their use of terminology in Complementary and Alternative Medicine (CAM).

METHODS

Based on a research question addressing the validity of spinal palpation for the diagnosis of neuromuscular dysfunction, we developed four search concepts with their respective controlled vocabulary and key terms. We calculated the frequency of MeSH, descriptors, and keywords used by authors in titles and abstracts in comparison to standard practices in semantic and analytic indexing in MEDLINE, MANTIS, CINAHL, and Web of Science.

RESULTS

Multiple searches resulted in the final selection of 38 relevant studies that were indexed at least in one of the four selected databases. Of the four search concepts, validity showed the greatest inconsistency in terminology among authors, indexers and investigators. The use of spinal terms showed the greatest consistency. Of the 22 neuromuscular dysfunction terms provided by the investigators, 11 were not contained in the controlled vocabulary and six were never used by authors or indexers. Most authors did not seem familiar with the controlled vocabulary for validity in the area of neuromuscular dysfunction. Recently, standard glossaries have been developed to assist in the research development of manual medicine.

CONCLUSIONS

Searching biomedical databases for CAM is challenging due to inconsistent use of controlled vocabulary and indexing procedures in different databases. A standard terminology should be used by investigators in conducting their search strategies and authors when writing titles, abstracts and submitting keywords for publications.

Spinal palpation: The challenges of information retrieval using available databases

PURPOSE

This study addressed 2 questions: first, what is the yield of PubMed MEDLINE for complementary and alternative medicine (CAM) studies compared to other databases; second, what is an effective search strategy to answer a sample research question on spinal palpation?

METHODS

We formulated the following research question: "What is the reliability of spinal palpation procedures?" We identified specific Medical Subject Headings (MeSH) and key terms as used in osteopathic medicine, allopathic medicine, chiropractic, and physical therapy. Using PubMed, we formulated an initial search template and applied it to 12 additional selected databases. Subsequently, we applied the inclusion criteria and evaluated the yield in terms of precision and sensitivity in identifying relevant studies.

RESULTS

The online search result of the 13 databases identified 1189 citations potentially addressing the research question. After excluding overlapping and nonpertinent citations and those not meeting the inclusion criteria, 49 citations remained. PubMed yielded 19, while MANTIS (Manual Alternative and Natural Therapy Index System), a manual therapy database, yielded 35 citations. Twenty-six of the 49 online citations were repeatedly indexed in 3 or more databases. Content experts and selective manual searches identified 11 additional studies. In all, we identified 60 studies that addressed the research question. The cost of the databases used for conducting this search ranged from free-of-charge to $43,000 per year for a single network subscription.

CONCLUSIONS

Commonly used databases often do not provide accurate indexing or coverage of CAM publications. Subject-specific specialized databases are recommended. Access, cost, and ease of using specialized databases are limiting factors.

Content validity of manual spinal palpatory exams - A systematic review

BACKGROUND

Many health care professionals use spinal palpatory exams as a primary and well-accepted part of the evaluation of spinal pathology. However, few studies have explored the validity of spinal palpatory exams. To evaluate the status of the current scientific evidence, we conducted a systematic review to assess the content validity of spinal palpatory tests used to identify spinal neuro-musculoskeletal dysfunction.

METHODS

Review of eleven databases and a hand search of peer-reviewed literature, published between 1965-2002, was undertaken. Two blinded reviewers abstracted pertinent data from the retrieved papers, using a specially developed quality-scoring instrument. Five papers met the inclusion/exclusion criteria.

RESULTS

Three of the five papers included in the review explored the content validity of motion tests. Two of these papers focused on identifying the level of fixation (decreased mobility) and one focused on range of motion. All three studies used a mechanical model as a reference standard. Two of the five papers included in the review explored the validity of pain assessment using the visual analogue scale or the subjects' own report as reference standards. Overall the sensitivity of studies looking at range of motion tests and pain varied greatly. Poor sensitivity was reported for range of motion studies regardless of the examiner's experience. A slightly better sensitivity (82%) was reported in one study that examined cervical pain.

CONCLUSIONS

The lack of acceptable reference standards may have contributed to the weak sensitivity findings. Given the importance of spinal palpatory tests as part of the spinal evaluation and treatment plan, effort is required by all involved disciplines to create well-designed and implemented studies in this area.

Use of complementary and alternative medicine among the ethnic elderly

OBJECTIVE

We sought to explore whether the elderly are high users of complementary and alternative medicine (CAM), and to determine which modalities they use. We also sought to describe patterns and positive predictors of CAM use among 3 ethnically diverse groups of community-residing elderly.

DESIGN

A 7-page questionnaire was developed and translated into Spanish and Vietnamese.

PARTICIPANTS

A population of 525 community-residing elderly completed personal interviews.

RESULTS

Two hundred and fifty-one respondents (47.8%) reported using CAM over the past year. Dietary supplements (47.4%), chiropractic (16.3%), home remedies (15.9%), acupuncture (15.1%), and Oriental medicine (12.8%), were the most frequently cited therapies. The majority of CAM users (62.4%) did not inform their physicians that they were using it, but 58% consulted their physician for the same problem for which they used CAM. Family and friends were most relied upon for making the choice of therapy. Among the 3 ethnic groups studied, Asians were higher users of acupuncture (28%) and Oriental medicine (31%), Hispanics were higher users of dietary supplements (56%), home remedies (25%), and curanderos (8%), while white non-Hispanics were higher users of chiropractic (42%), massage (20%), vitamins (20%), diet (17%), and psychospiritual (15%) modalities. Pain was a higher indicator of CAM use among Asians, gastrointestinal problems and diabetes among Hispanics, and stress/fatigue and cardiovascular problems among white non-Hispanics.

CONCLUSION

Findings indicated a high use of CAM among the elderly and emphasize the likelihood that elderly immigrants use those therapies with which they are familiar. Modalities and conditions varied with the ethnicity of respondents.

Effectiveness of four conservative treatments for subacute low back pain: a randomized clinical trial

STUDY DESIGN

A randomized, assessor-blinded clinical trial was conducted.

OBJECTIVE

To investigate the relative effectiveness of three manual treatments and back school for patients with subacute low back pain.

SUMMARY OF BACKGROUND DATA

Literature comparing the relative effectiveness of specific therapies for low back pain is limited.

METHODS

Among the 5925 inquiries, 206 patients met the specific admission criteria, and 200 patients randomly received one of four treatments for 3 weeks: back school, joint manipulation, myofascial therapy, and combined joint manipulation and myofascial therapy. These patients received assessments at baseline, after 3 weeks of therapy, and 6 months after the completion of therapy. The primary outcomes were evaluated using visual analog pain scales and Roland-Morris activity scales.

RESULTS

All four groups showed significant improvement in pain and activity scores after 3 weeks of care, but did not show further significant improvement at the 6-month follow-up assessment. No statistically significant between-group differences were found either at the 3-week or 6-month reassessments.

CONCLUSIONS

For subacute low back pain, combined joint manipulation and myofascial therapy was as effective as joint manipulation or myofascial therapy alone. Additionally, back school was as effective as three manual treatments.

Accuracy of self-monitoring of blood glucose: impact on diabetes management decisions during pregnancy

PURPOSE

This study tested the hypothesis that the accuracy of self-monitoring of blood glucose (SMBG) values of patients with diabetes during pregnancy deviates substantially from reference values.

METHODS

The patients' glucose values were measured on 6 different SMBG meters; reference values were from the HemoCue B Glucose Analyzer. Over a 5-year period, 1973 comparisons between SMBG values and reference values were recorded during clinic visits and used for this study. Data were analyzed for percent of values that varied more than +/- 10.5% and +/- 15.5% from the reference value. Out-of-range data at each variance level were analyzed to determine the impact on medical management if decisions were based solely on SMBG values.

RESULTS

One third of SMBG readings deviated significantly, which could adversely affect treatment for half of these patients if diabetes management was based on SMBG values. At the 10.5% deviation level, 34% of SMBG meter readings were out of range; 54% of these would have implied erroneous treatment. At the 15.5% deviation level, 18% were out of range; 63% of these would have implied erroneous management.

CONCLUSIONS

The accuracy of home meters should be verified at regular intervals, and SMBG values should not be the sole criterion for diabetes management during pregnancy.

Rab6 coordinates a novel Golgi to ER retrograde transport pathway in live cells

We visualized a fluorescent-protein (FP) fusion to Rab6, a Golgi-associated GTPase, in conjunction with fluorescent secretory pathway markers. FP-Rab6 defined highly dynamic transport carriers (TCs) translocating from the Golgi to the cell periphery. FP-Rab6 TCs specifically accumulated a retrograde cargo, the wild-type Shiga toxin B-fragment (STB), during STB transport from the Golgi to the endoplasmic reticulum (ER). FP-Rab6 TCs associated intimately with the ER, and STB entered the ER via specialized peripheral regions that accumulated FP-Rab6. Microinjection of antibodies that block coatomer protein I (COPI) function inhibited trafficking of a KDEL-receptor FP-fusion, but not FP-Rab6. Additionally, markers of COPI-dependent recycling were excluded from FP-Rab6/STB TCs. Overexpression of Rab6:GDP (T27N mutant) using T7 vaccinia inhibited toxicity of Shiga holotoxin, but did not alter STB transport to the Golgi or Golgi morphology. Taken together, our results indicate Rab6 regulates a novel Golgi to ER transport pathway.

Mechanisms of nuclear positioning

The mechanisms underlying two types of microtubule-dependent nuclear positioning are discussed. ‘MTOC-dependent nuclear positioning’ occurs when a nucleus is tightly associated with a microtubule organizing center (MTOC). ‘Nuclear tracking along microtubules’ is analogous to the motor-driven motility of other organelles and occurs when the nucleus lacks an associated MTOC. These two basic types of microtubule-dependent nuclear positioning may cooperate in many proliferating animal cells to achieve proper nuclear positioning. Microtubule polymerization and dynamics, motor proteins, MAPs and specialized sites such as cortical anchors function to control nuclear movements within cells.

Movement of nuclei along microtubules in Xenopus egg extracts

Microtubules are implicated in the movement and positioning of nuclei in many cell types. Nuclei can be moved by forces acting on microtubules nucleated at the spindle pole body, as in fungi [1], or microtubules nucleated at the centrosome, as during migration of the male (sperm) pronucleus towards the centre of the zygote after fertilization [2] [3] [4]. The dramatic movements of the female pronucleus towards the male pronucleus potentially involve another mechanism: movement along the microtubules of the sperm aster towards their slower growing, attached or 'minus' ends [3] [5]. Here, we have reconstituted this last type of nuclear movement in vitro. Synthetic nuclei assembled in cytoplasmic extracts made from interphase Xenopus eggs move along microtubules towards their minus ends. We provide strong experimental evidence that cytoplasmic dynein is the motor for nuclear movement in this in vitro system, and discuss our results in terms of current knowledge of motility of the endoplasmic reticulum.

Rab11 regulates recycling through the pericentriolar recycling endosome

Small GTPases of the rab family are crucial elements of the machinery that controls membrane traffic. In the present study, we examined the distribution and function of rab11. Rab11 was shown by confocal immunofluorescence microscopy and EM to colocalize with internalized transferrin in the pericentriolar recycling compartment of CHO and BHK cells. Expression of rab11 mutants that are preferentially in the GTP- or GDP-bound state caused opposite effects on the distribution of transferrin-containing elements; rab11-GTP expression caused accumulation of labeled elements in the perinuclear area of the cell, whereas rab11-GDP caused a dispersion of the transferrin labeling. Functional studies showed that the early steps of uptake and recycling for transferrin were not affected by overexpression of rab11 proteins. However, recycling from the later recycling endosome was inhibited in cells overexpressing the rab11-GDP mutant. Rab5, which regulates early endocytic trafficking, acted before rab11 in the transferrin-recycling pathway as expression of rab5-GTP prevented transport to the rab11-positive recycling endosome. These results suggest a novel role for rab11 in controlling traffic through the recycling endosome.

The core of the mammalian centriole contains gamma-tubulin

BACKGROUND

The microtubule network, upon which transport occurs in higher cells, is formed by the polymerization of alpha and beta tubulin. The third major tubulin isoform, gamma tubulin, is believed to serve a role in organizing this network by nucleating microtubule growth on microtubule-organizing centers, such as the centrosome. Research in vitro has shown that gamma tubulin must be restored to stripped centrioles to regenerate the centrosomal functions of duplication and microtubule nucleation.

RESULTS

We have re-examined the localization of gamma tubulin in isolated and in situ mammalian centrosomes using a novel immunocytochemical technique that preserves antigenicity and morphology while allowing increased accessibility. As expected, alpha tubulin was localized in cytoplasmic and centriolar barrel microtubules and in the associated pericentriolar material. Foci of gamma tubulin were observed at the periphery of the organized pericentriolar material, as reported previously, often near the termini of microtubules. A further and major location of gamma tubulin was a structure within the proximal end of the centriolar barrel. The distributions were complementary, in that alpha tubulin was excluded from the core of the centriole, and gamma tubulin was excluded from the microtubule barrel.

CONCLUSIONS

We have shown that gamma tubulin is localized both in the pericentriolar material and in the core of the mammalian centriole. This result suggests that gamma tubulin has a role in the centriolar duplication process, perhaps as a template for growth of the centriolar microtubules, in addition to its established role in the nucleation of astral microtubules.

Orientation of spindle axis and distribution of plasma membrane proteins during cell division in polarized MDCKII cells

MDCKII cells differentiate into a simple columnar epithelium when grown on a permeable support; the monolayer is polarized for transport and secretion. Individual cells within the monolayer continue to divide at a low rate without disturbing the function of the epithelium as a barrier to solutes. This presents an interesting model for the study of mitosis in a differentiated epithelium which we have investigated by confocal immunofluorescence microscopy. We monitored the distribution of microtubules, centrioles, nucleus, tight junctions, and plasma membrane proteins that are specifically targeted to the apical and basolateral domains. The stable interphase microtubule cytoskeleton was rapidly disassembled at prophase onset and reassembled at cytokinesis. As the interphase microtubules disassembled at prophase, the centrioles moved from their interphase position at the apical membrane to the nucleus and acquired the ability to organize microtubule asters. Orientation of the spindle parallel to the plane of the monolayer occurred between late prophase and metaphase and persisted through cytokinesis. The cleavage furrow formed asymmetrically perpendicular to the plane of the monolayer initiating at the basolateral side and proceeding to the apical domain. The interphase microtubule network reformed after the centrioles migrated from the spindle poles to resume their interphase apical position. Tight junctions (ZO-1), which separate the apical from the basolateral domains, remained assembled throughout all phases of mitosis. E-cadherin and a 58-kD antigen maintained their basolateral plasma membrane distributions, and a 114-kD antigen remained polarized to the apical domain. These proteins were useful for monitoring the changes in shape of the mitotic cells relative to neighboring cells, especially during telophase when the cell shape changes dramatically. We discuss the changes in centriole position during the cell cycle, mechanisms of spindle orientation, and how the maintenance of polarized plasma membrane domains through mitosis may facilitate the rapid reformation of the polarized interphase cytoplasm.

Attempts to prevent falls and injury: a prospective community study

At 16 senior centers, we studied the effectiveness of exercise and cognitive-behavioral programs, compared with a discussion control program, in reducing falls and injuries among 230 older adults. After 1 year of the programs, we observed no significant difference in time to first fall. Even though a relatively high percentage (38.6%) suffered at least one fall, only 7.8% of these community-residing elderly required medical attention. Secondary outcome measures such as strength, balance, fear of falling, and perceived health did not significantly change.

Intergenerational relations: Pre-med students at senior centers

Misconceptions about aging and a negative bias against caring for older adults entail unfortunate consequences for society. This study explored the potential of frequent personal contact in reducing misconceptions and improving personal attitude towards older adults. Thirty students, predominantly Asian, with English as their second language, attended senior centers three times per week for 11 months, on the average. They assisted in teaching health promotion classes for the prevention of falls, conducted health assessments by interview, and collected physiological data. At the senior centers, a sample of 70 older adult Americans participated in the health promotion classes and in this evaluation of intergenerational relations. Students completed anonymously two questionnaires; one was objective, testing misconceptions about aging; the other was subjective, rating their reactions to elders at senior centers. Older adults completed, also anonymously, a subjective questionnaire on their reactions to students at their centers. Results on students' misconceptions about aging were similar to those among students at Duke University who did not experience frequent personal contact with well elderly. According to the Facts on Aging Quiz, the overall attitude among students at senior centers was more biased in the negative direction than among Duke students, especially among students who had just joined the project. However, in the subjective questionnaires, students at senior centers expressed feeling at ease at the centers and they disagreed with statements of impatience and frustration. Older adults at the centers had a positive attitude toward the students and most thought that students were sympathetic.

Adjusting for recall bias with the proportional hazards model

In studying falling frequency in the elderly, we observed that having subjects keep a diary led to a larger number of falls reported than had been noted in a previous study in the same population. The previous study asked subjects to report any falls in the previous three months. We considered two related explanations for the observation of lower incidence reports with a 3-month recall survey. First, there may have been under-reporting of falls due to recall bias. Second, the less severe falls (which did not result in injuries) may not be reported. We suggest that the proportional hazards model may be used to adjust studies in which recall is used to determine incidence and time to falls.

Falling among the sensorially impaired elderly

Recent studies of the healthy elderly indicate that accidental falls account for many lengthy hospital stays and permanent disabilities. An ongoing investigation by our group is examining the contribution of neuromuscular feedback and the possible substitution of visual-perceptual feedback as a major contributor to falling in this population. This combination of decreased weighting of neuromuscular factors and increased weighting of the visual-perceptual factors led to the following hypothesis: Those persons who cannot see should show less change in frequency of falling as they age than sighted cohorts. The deaf, who rely more than others on visual perceptual stimuli, are less likely to fall as they age than the general elderly population, who first begin to rely more heavily on visual stimuli when they age. Thus, the deaf and blind constitute a population whose change in frequency of falls with increased age should differ markedly from change in the frequency of falls among the nonblind and nondeaf segments of the population. Our results support the hypothesis. The blind demonstrated a higher rate of falls than the deaf or nonimpaired population. However, the more elderly blind failed to show the increase in falling demonstrated by the deaf and nonimpaired. If these findings are confirmed in subsequent studies, the nonimpaired and deaf elderly could be trained to focus on visual feedback. The blind may be able to reduce the frequency of falls by enhancing musculoskeletal feedback and strength via exercise.

Mapping of the two mouse engrailed-like genes: close linkage of En-1 to dominant hemimelia (Dh) on chromosome 1 and of En-2 to hemimelic extra-toes (Hx) on chromosome 5

The mouse genome contains two genes, En-1 and En-2, with sequence similarity to the engrailed gene of Drosophila. Using conventional linkage crosses, we have shown that En-1 maps approximately 0.28 cM distal to the dominant hemimelia (Dh) gene on chromosome 1 and that En-2 maps approximately 1.1 cM proximal to the hemimelic extra-toes (Hx) gene on chromosome 5. We have also shown by Northern blot analysis that En-1 transcripts in Dh homozygotes and En-2 transcripts in Hx homozygotes are of normal size and abundance. These data, in conjunction with previously published studies of the patterns of En-1 and En-2 expression in developing mouse embryos, suggest that Dh and Hx are very unlikely to be mutant alleles of En-1 or En-2, respectively. Instead, we suggest that En-1-Dh and En-2-Hx represent paralogous linkage groups that evolved following duplication of a common ancestral chromosome segment.

Specific efficacy expectations mediate exercise compliance in patients with COPD

Social learning theory has generated two different approaches for the assessment of expectancies. Bandura argues that expectancies are specific and do not generalize. Therefore, he prefers measures of specific efficacy expectations. Others endorse the role of generalized expectancies measured by locus of control scales. The present study examines specific versus generalized expectancies as mediators of changes in exercise behavior among 60 older adult patients with Chronic Obstructive Pulmonary Disease. The patients were given a prescription to increase exercise and randomly assigned to experimental groups or control groups. All groups received attention but only experimental groups received training to increase their exercise. After 3 months, groups given specific training for compliance with walking significantly increased their activity in comparison to the control group receiving only attention. These changes were mediated by changes in perceived efficacy for walking, with efficacy expectations for other behaviors changing as a function of their similarity to walking. A generalized health locus of control expectancy measure was less clearly associated with behavior change. The results are interpreted as supporting Bandura's version of social theory.

Visual perception dominance of fallers among community-dwelling older adults

The authors postulated that older adult fallers show a greater tendency than older adult nonfallers to rely more on visual information sources in maintaining upright posture than on kinesthetic and vestibular cues. This paper presents descriptive statistics on 199 older adults living independently in the community. Their visual perception of the vertical and horizontal was analyzed with respect to age, sex, health status, and severity of injury as a result of a fall. The finding of significant impairments for fallers in visual perceptual abilities confirmed a trend previously established by one of the authors (Tobis). When the visual field entailed only misleading or ambiguous cues in the form of a tilted frame, fallers again showed a larger error than nonfallers in establishing the vertical and horizontal. The authors feel that this relatively greater dependence on visual sources may develop in response to impairment of feedback on posture and gait from the kinesthetic and vestibular systems as a result of age and chronic health problems. Errors in visual perception of the vertical and horizontal intercorrelated with age, sex, and a large number of medical problems. However, visual variables were more important in predicting faller status than physical characteristics.

Parental response to mid-trimester therapeutic abortion following amniocentesis

This article reports the results of a retrospective study designed to examine the responses of couples to genetic amniocentesis and subsequent therapeutic abortions due to birth defects. Fourteen women and 12 men were interviewed by experienced interviewers using a structured format designed by the authors, and each interview was audiotaped for later rating. The 5 raters (all women) were instructed to independently rate each interview using forms designed by the authors to elicit information about many aspects of the participant's individual responses as well as perceptions of spouse's responses to the process of pregnancy, amniocentesis, therapeutic abortion, and sequelae. Ratings of all 5 raters were conjoined and an homogeneous narrative was constructed for each interview. Results indicate, in general, that the respondent couples coped well with this experience. In fact 70 per cent of the respondent couples described their marital relationships as becoming closer as a result of their experience. Only a few participants reported long-term deleterious effects. Most couples coped by relying on relatives, friends, and occasionally, professional counsellors. In addition, most participants in this study suggested ways to improve the medical and psychological aspects of this experience.

Specific efficacy expectations mediate exercise compliance in patients with COPD

Social learning theory has generated two different approaches for the assessment of expectancies. Bandura argues that expectancies are specific and do not generalize. Therefore, he prefers measures of specific efficacy expectations. Others endorse the role of generalized expectancies measured by locus of control scales. The present study examines specific versus generalized expectancies as mediators of changes in exercise behavior among 60 older adult patients with Chronic Obstructive Pulmonary Disease. The patients were given a prescription to increase exercise and randomly assigned to experimental groups or control groups. All groups received attention but only experimental groups received training to increase their exercise. After 3 months, groups given specific training for compliance with walking significantly increased their activity in comparison to the control group receiving only attention. These changes were mediated by changes in perceived efficacy for walking, with efficacy expectations for other behaviors changing as a function of their similarity to walking. A generalized health locus of control expectancy measure was less clearly associated with behavior change. The results are interpreted as supporting Bandura's version of social theory.

Midtrimester amniocentesis. Subjective maternal responses

Studies, through questionnaire and interview, of couples who elect or decline midtrimester amniocentesis demonstrate that both groups cope well with new decisions surrounding this procedure. The pregnancy monitored by genetic amniocentesis does not appear to receive special status as viewed by the parents, nor is the developing fetus placed in a special category during the pregnancy.