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Significant salinity anomalies have been observed in the Arctic Ocean surface layer during the last decade. Our study is based on an extensive gridded dataset of winter salinity in the upper 50 m layer of the Arctic Ocean for the periods 1950–1993 and 2007–2012, obtained from ~20 000 profiles. We investigate the interannual variability of the salinity fields, identify predominant patterns of anomalous behavior and leading modes of variability, and develop a statistical model for the prediction of surface-layer salinity. The statistical model is based on linear regression equations linking the principal components of surface-layer salinity obtained through empirical orthogonal function decomposition with environmental factors, such as atmospheric circulation, river runoff, ice processes and water exchange with neighboring oceans. Using this model, we obtain prognostic fields of the surface-layer salinity for the winter period 2013–2014. The prognostic fields generated by the model show tendencies of surface-layer salinification, which were also observed in previous years. Although the used data are proprietary and have gaps, they provide the most spatiotemporally detailed observational resource for studying multidecadal variations in basin-wide Arctic salinity. Thus, there is community value in the identification, dissemination and modeling of the principal modes of variability in this salinity record.
We present the results of stable carbon and nitrogen isotope analyses of bone collagen and bone bioapatite from the ancient Maya center of Minanha, Belize (ca. 100 B.C. to A.D. 1260). The purpose of this research was to reconstruct diet and investigate the influence of sociopolitical and environmental factors. Overall, diet was relatively stable over time, with maize being a staple in all periods. Maize consumption reached its peak in the transitional Early to Middle Classic periods and decreased over time. When isotope data from dry periods were compared to normal periods, there were no significant differences, although comparisons of isotope data by burial location and type suggest that the apical or ruling elite consumed a more diverse diet, with more animal protein, relative to the lesser elites. The temporal variability in maize consumption seems best explained by sociopolitical factors documented at Minanha and within the Vaca Plateau. This study demonstrates the resilience of ancient subsistence practices in the face of climatic instability and highlights the impact that social and political factors can have on diet and subsistence economy.
The objective of this study was to determine whether hatha yoga is an efficacious adjunctive intervention for individuals with continued depressive symptoms despite antidepressant treatment.
We conducted a randomized controlled trial of weekly yoga classes (n = 63) v. health education classes (Healthy Living Workshop; HLW; n = 59) in individuals with elevated depression symptoms and antidepressant medication use. HLW served as an attention-control group. The intervention period was 10 weeks, with follow-up assessments 3 and 6 months afterwards. The primary outcome was depression symptom severity assessed by blind rater at 10 weeks. Secondary outcomes included depression symptoms over the entire intervention and follow-up periods, social and role functioning, general health perceptions, pain, and physical functioning.
At 10 weeks, we did not find a statistically significant difference between groups in depression symptoms (b = −0.82, s.e. = 0.88, p = 0.36). However, over the entire intervention and follow-up period, when controlling for baseline, yoga participants showed lower levels of depression than HLW participants (b = −1.38, s.e. = 0.57, p = 0.02). At 6-month follow-up, 51% of yoga participants demonstrated a response (⩾50% reduction in depression symptoms) compared with 31% of HLW participants (odds ratio = 2.31; p = 0.04). Yoga participants showed significantly better social and role functioning and general health perceptions over time.
Although we did not see a difference in depression symptoms at the end of the intervention period, yoga participants showed fewer depression symptoms over the entire follow-up period. Benefits of yoga may accumulate over time.
Because individuals develop dementia as a manifestation of neurodegenerative or neurovascular disorder, there is a need to develop reliable approaches to their identification. We are undertaking an observational study (Ontario Neurodegenerative Disease Research Initiative [ONDRI]) that includes genomics, neuroimaging, and assessments of cognition as well as language, speech, gait, retinal imaging, and eye tracking. Disorders studied include Alzheimer’s disease, amyotrophic lateral sclerosis, frontotemporal dementia, Parkinson’s disease, and vascular cognitive impairment. Data from ONDRI will be collected into the Brain-CODE database to facilitate correlative analysis. ONDRI will provide a repertoire of endophenotyped individuals that will be a unique, publicly available resource.
The Compton Gamma-Ray Observatory (C-GRO) has completed a full-sky survey during which the number of known γ-ray pulsars has more than doubled. COMPTEL has observed the classical pulsars Crab and Vela on several occasions and has derived detailed pulse patterns and spectral parameters in the 0.7-30 MeV energy interval. The new C-GROγ-ray pulsars have different properties in terms of energy spectra and light-curve shapes, and, in fact, only the Crab is seen by all four C-GRO instruments. This raises intriguing questions about the particle acceleration processes and beaming taking place in the neutron magnetosphere. We have examined the COMPTEL data to add information on these objects in the 0.7-30 MeV energy interval and present evidence for the detection of one of them, PSR B1509-58. We have also undertaken a search for candidate radio pulsars whose ephemerides are well defined. The results of these analyses are presented.
Subject headings: gamma rays: observations — pulsars: general
Barbara M. Moskal, Colorado School of Mines,
Teri Reed, Dwight Look College of Engineering and Harold Vance Department of Petroleum Engineering at Texas A;&M,
Scott A. Strong, Colorado School of Mines
A concern across the field of education, as well as within engineering education, is the identification of effective instructional approaches. “Effective” can be defined in many ways, including increased learning gains, improved attitudes, and changes in the general appeal of a subject or topic to students. To determine the effectiveness of an approach, it is often necessary to measure changes in student constructs over time or to acquire a snapshot of students’ performances at a given point. In addition, teachers and researchers may be concerned with determining whether their approaches are equally effective across different student populations.
In engineering education, each of these assessment purposes receives increased emphasis at the program and student level owing to the existence of an accreditation board, ABET, Inc. (formerly known as the Accreditation Board for Engineering and Technology or ABET; see www.abet.org/history.shtml). ABET, Inc. requests that each accredited program demonstrate that its graduating seniors have achieved a set of program outcomes that can be found at the referenced website.
N-acetyl-glutamate synthase (NAGS) deficiency is a rare autosomal recessive urea cycle disorder (UCD) that uncommonly presents in adulthood. Adult presentations of UCDs include; confusional episodes, neuropsychiatric symptoms and encephalopathy. To date, there have been no detailed neurological descriptions of an adult onset presentation of NAGS deficiency. In this review we examine the clinical presentation and management of UCDs with an emphasis on NAGS deficiency. An illustrative case is provided. Plasma ammonia levels should be measured in all adult patients with unexplained encephalopathy, as treatment can be potentially life-saving. Availability of N-carbamylglutamate (NCG; carglumic acid) has made protein restriction largely unnecessary in treatment regimens currently employed. Genetic counselling remains an essential component of management of NAGS.
Although numerous studies have examined the latent structure of major depression, less attention has focused on mania. This paper presents the first investigation outside the USA to evaluate the psychometric properties of the DSM-IV criterion B mania symptoms using item response theory (IRT).
Data were drawn from the Australian 2007 National Survey of Mental Health and Well-Being (NSMHWB, n = 8841). The psychometric performance of the mania symptoms was evaluated using a two-parameter logistic model. Because substance use disorders (SUDs) frequently co-occur with mania and can influence manic symptom expression, differential item functioning (DIF) between mania respondents with/without a SUD diagnosis was also assessed.
Factor analysis supported a unidimensional trait underlying mania. The grandiosity symptom displayed the highest discrimination whereas discrimination was lowest for decreased need for sleep. Relatively speaking, grandiosity tapped the severe end and increased goal-oriented activities tapped the mild end of the mania severity continuum. The symptoms generally performed equivalently between those with/without a SUD diagnosis, with one exception; the activities with painful consequences symptom was endorsed at lower levels of severity, and hence more frequently, by those with a SUD diagnosis versus those without a SUD diagnosis.
Accurate conceptualization of latent structure has crucial theoretical, statistical and clinical implications. The symptoms generally performed well in distinguishing between respondents with differing levels of liability, but others did not, suggesting modification is warranted to ensure optimal use in epidemiological samples. Given the dearth of psychometric evaluation studies of mania, further research replicating these results is necessary.
To determine whether drinking water contaminated with antimicrobial-resistant E. coli is associated with the carriage of resistant E. coli, selected households sending water samples to Ontario and Alberta laboratories in 2005–2006 were asked to participate in a cross-sectional study. Household members aged ⩾12 years were asked to complete a questionnaire and to submit a rectal swab. In 878 individuals, 41% carried a resistant strain of E. coli and 28% carried a multidrug-resistant strain. The risk of carriage of resistant E. coli was 1·26 times higher for users of water contaminated with resistant E. coli. Other risk factors included international travel [prevalence ratio (PR) 1·33], having a child in nappies (PR 1·33), being male (PR 1·33), and frequent handling of raw red meats (PR 1·10). Protecting private water sources (e.g. by improving systems to test and treat them) may help slow the emergence of antimicrobial resistance in E. coli.
Heterojunction p++ GeSi / Si internal photoemission (HIP) detectors deposited by ultra high vacuum chemical vapor deposition (UHV/CVD) were investigated as alternatives to silicide Schottky-barrier type detectors for infrared focal plane arrays. HIP structures were grown using SiH4, GeH4, and B2H6 source gases on (100) p- Si substrates patterned with thermal oxide windows. Selective epitaxy was maintained over a range of boron concentrations (6×1019 – 6.5×1020 cm-3) and Ge fractions (0.38–0.50), and a maximum selective thickness of ~300Å was determined for silicon growth at 550°C. These structures were fabricated into IR detectors using techniques compatible with standard Si focal plane array processing technology. Photoresponse data were analyzed according to the modified Fowler equation, indicating cut-off wavelengths of 5–12 (μm) and Cl values of 8–21 (%/eV) depending on sample parameters. I(V) characteristics were also measured at various temperatures, yielding electrical barrier heights consistent with optical measurements.
The miniaturization of electrochemical transducers is crucial for the development of implantable biosensors, wearable microdetectors, and remote sensing networks due to the small dimensions required in these applications. As sensors scale, the analytical response degrades and integrated instrumentation is required to maintain acceptable detection limits. This work details the development of CMOS-integrated liquid chemical sensors. The sensors were cost-effectively post-processed on top of foundry-fabricated CMOS electronics using thin-film techniques. CMOS-integrated voltammetric sensors demonstrated a 25x improvement in detection limit/electrode area versus passive sensors. CMOS-integrated, ion-selective electrodes demonstrated a 50x improvement in lifetime and a 200x improvement in response time versus passive sensors. With their improved performance, these smart sensors can be used in a wide range of applications and can additionally serve as enabling technologies for more complex, chip-scale systems.
In order to characterize the nature and extent of neuropsychological dysfunction in primary lateral sclerosis (PLS), we studied prospectively cognitive, emotional, and behavioral functioning in PLS, and compared performances to functioning in amyotrophic lateral sclerosis (ALS).
Eighteen patients with PLS and 13 patients with ALS completed a neuropsychological test battery assessing both cognitive skills and emotional/behavioral functioning.
Both PLS and ALS groups scored broadly within normal limits (mean T-scores greater than 40) on all cognitive measures and no significant between-group differences were found with the exception of one variable. However, when examined on a case by case basis, the data revealed considerable heterogeneity amongst patients in both groups. Overall, 39% of PLS patients and 31% of ALS patients were considered cognitively impaired. A higher than expected frequency of abnormal scores was noted for several tests of executive function in both groups, and a majority of PLS patients also exhibited abnormal behavioural symptoms. There was no relationship in PLS or ALS groups between cognitive functioning and disease duration, current site of disease, site of onset, functional status, and respiratory variables. Comparison between the PLS and ALS groups indicated virtually no differences in cognitive test scores and overall emotional/behavioural symptoms.
We observed deficits in cognition and behaviour in a significant proportion of PLS patients which were comparable to those observed in ALS cases. Although deficits were not in the range of frontotemporal dementia, both ALS and PLS cases demonstrated deficits most prominently on tests of executive functioning.
The purpose of this study was to evaluate Canadian amyotrophic lateral sclerosis (ALS) centres with respect to: 1) the prevalence of Non-invasive positive pressure ventilation (NIPPV) and invasive mechanical ventilation via tracheostomy (TV) utilization, 2) the approach to NIPPV use, focusing upon the currently employed initiation criteria and 3) the barriers influencing NIPPV administration.
A descriptive survey research design aimed to obtain quantitative data and open-ended responses from an active physician at each of the 15 multidisciplinary Canadian ALS centres.
The principal findings of this study were: 1) NIPPV and TV are used in 18.3% and 1.5% of patients at Canadian ALS centres, respectively, 2) symptoms of respiratory insufficiency, namely orthopnea (clinical significance rated at 9.00/10 ± 1.48), dyspnea (8.27 ± 1.95) and morning headache (7.55 ± 1.21) are the most significant indicators for NIPPV initiation, 3) the primary barriers to NIPPV utilization are patient intolerance (70% of centres) and inaccessibility of respirologists and ventilation technologists (50% of centres).
Variability in NIPPV use has an impact upon the management of Canadian ALS patients. The establishment of more definitive NIPPV initiation criteria, emphasizing respiratory symptoms, and the attenuation of barriers to NIPPV use should be targeted so as to ensure optimal care for all ALS patients.
Psychological literature and clinical lore suggest that there may be systematic differences in how various demographic groups experience depressive symptoms, particularly somatic symptoms. The aim of the current study was to use methods based on item response theory (IRT) to examine whether, when equating for levels of depression symptom severity, there are demographic differences in the likelihood of reporting DSM-IV depression symptoms.
We conducted a secondary analysis of a subset (n=13 753) of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) dataset, which includes a large epidemiological sample of English-speaking Americans. We compared data from women and men, Hispanics and non-Hispanic Whites, African Americans and Whites, Asian Americans and Whites, and American Indians and Whites.
There were few differences overall, although the differences that we did find were primarily limited to somatic symptoms, and particularly appetite and weight disturbance.
For the most part, individuals responded similarly to the criteria used to diagnose major depression across gender and across English-speaking racial and ethnic groups in the USA.