cssi/SciSciGPT-SciSciNet huggingface dataset:
Multi-scale modeling of thermo-oxidation effects on the flexural behavior of cross-ply bismaleimide composites

Mechanical properties of high-temperature polymer matrix composites deteriorate during their service. Oxidation plays a significant role in determining the residual elastic and strength properties of the composite. The present work investigates the oxidative aging damage of cross-ply bismaleimide composites, both experimentally and numerically. Also, this work introduces a better understanding of the significant damage mechanisms, and their respective time ranges. Micro/macro-scale thermo-oxidation behavior and flexural failure were simulated for 1,700 hours of aging. Thermo-oxidation behavior of the cross-ply laminates was simulated using a multi-fiber multi-layer representative volume element. Thermo-oxidation is a diffusion–reaction phenomenon that depends on temperature and oxidation state in time and space domains. In this work, the proportionality between oxidation state evolution and reaction rate was modeled using a new form of time-dependent parameter. Owing to aging damage, the required properties for the flexural test simulation were reduced in the meso-scale. The current study presents a damage state assuming proportionality between the average crack length and oxidized layer thickness based on a continuum damage mechanics approach. Scanning electron micrographs showed that the onset of the “blunt” transverse (through-thickness) micro-cracking/debonding in the superficial layers was at 500 hours under $176.7~{}^{\circ}\mbox{C}$ ( $350~^{\circ}\mbox{F}$ ), where oxidative cracking dominates aging mechanisms. The “blunt” micro-cracks propagated in the transverse direction near 1000 hours rendering the crack faces in contact with the oxidative air. After about 1,700 hours of aging, the weight loss ratio was 0.5%, and the flexural modulus and strength reduced by 19% and 10%, respectively. Prior to 500 hours, where cracking was not noticeable in the “crack-free region”, the strengths reduction was not significant based on the numerical simulations. In the crack-free and oxidative damage dominated regions, the elastic property numerical reduction was significant.
A Case of Undetected Neuroborreliosis in a 75-Year-Old Chinese Male.

Lyme disease is a multisystem infection caused by the spirochete Borrelia burgdorferi sensu stricto that manifests with characteristic symptoms in patients. Patients are identified based on their clinical symptoms and then diagnosed through enzyme-linked immunosorbent assay (ELISA), Western blot, and blood culture techniques. Here, we present the case of a 75-year-old, Northeast suburban resident complaining of unstable gait, high fevers, malaise, myalgia, and confusion. This patient’s symptoms were nonspecific, and his lab titers and blood cultures were repeatedly negative during his stay. It was only late in the course of his treatment that blood titers and cerebrospinal fluid analysis were positive for Lyme IgG and IgM. He was treated with intravenous doxycycline and prescribed oral doxycycline on discharge, resulting in a full recovery. We express the need for physicians to consider Lyme disease in endemic patients presenting with nonspecific systemic signs.
Dorsal root ganglion disorders

Disorders of the dorsal root ganglia are increasingly recognized as causes of sensory loss and ataxia. This chapter covers first the development, anatomy, chemistry, and physiology of the dorsal root ganglia. This is followed by discussions of the clinical manifestations, diagnosis, and management of disorders of the dorsal root ganglia. This includes paraneoplastic and immune-mediated nonmalignant inflammatory sensory polyganglionopathies as well as sensory ganglionopathy associated with Sjogren syndrome and toxic and nutritional ganglionopathies.
Measurements of Bottom Variability During Swat New Jersey Shelf Experiments

Chirp sonar and vibracore measurements of bottom variability from scales of centimeters to tens of meters have been conducted during the recent Shallow Water Acoustic Technology (SWAT) experiments at the New Jersey Shelf. Chirp sonar (2–12 kHz) data were used to invert bottom geoacoustic properties with sub-meter resolution. Sediment properties such as density, porosity and sound-speed profiles are inverted from coherent acoustic returns at several sites with well-characterized subbottom reflectors. Also, centimeter-resolution geaoacoustic properties were measured from several vibracores collected along the survey tracks. Chirp sonar inversion results compare favorably with those of co-located sediment core measurements. Both deterministic and stochastic features are deduced from the sonar surveys and co-located sediment core data. Effects of measured bottom spatial variability on the broadband acoustic propagation are also studied by using a Parabolic Equation (PE) model. It was concluded that, in addition to the oceanographic variability, the seafloor and subbottom spatial variability might further spatially decorrelate the acoustic signals propagating in shallow waters.
Designing Signals with Good Correlation and Distribution Properties

Sequences with good correlation and distribution properties play a central role in various areas of signal processing. In this paper, we propose an efficient computational framework for designing sequences with two key properties: (i) an impulse-like auto-correlation, and (ii) a probability distribution of sequence entries which is uniform in nature; although the results can be easily extended to an arbitrary distribution. The proposed method is based on utilizing the Fast Fourier Transform (FFT) operations, and thus can generate very long sequences in small time frames. Several numerical examples are provided to exhibit the performance of the suggested construction framework.
Composition's Imagined Geographies: The Politics of Space in the Frontier, City, and Cyberspace

n their recent article on "Importing Composition: Teaching and Researching Academic Writing Beyond North America," Mary N. Muchiri and her co-authors challenge our assumptions that composition is "universal" in its uses and applications, and that writing instructors and writing students do not occupy particular geographic locations. Muchiri et al. remind readers that composition is very much a product of North America and of capitalism and illustrate what happens to composition research when it is exported-how it changes in a different, de-localized context of its origination. "Importing Composition" highlights some of the assumptions that form the basis of U.S. research on academic writing-assumptions that sometimes seem "bizarre" in a new context (176). In our limited notions of
Simulated hip abductor strengthening reduces peak joint contact forces in patients with total hip arthroplasty.

Abstract Lower extremity muscle strength training is a focus of rehabilitation following total hip arthroplasty (THA). Strength of the hip abductor muscle group is a predictor of overall function following THA. The purpose of this study was to investigate the effects of hip abductor strengthening following rehabilitation on joint contact forces (JCFs) in the lower extremity and low back during a high demand step down task. Five THA patients performed lower extremity maximum isometric strength tests and a stair descent task. Patient-specific musculoskeletal models were created in OpenSim and maximum isometric strength parameters were scaled to reproduce measured pre-operative joint torques. A pre-operative forward dynamic simulation of each patient performing the stair descent was constructed using their corresponding patient-specific model to predict JCFs at the ankle, knee, hip, and low back. The hip abductor muscles were strengthened with clinically supported increases (0–30%) above pre-operative values in a probabilistic framework to predict the effects on peak JCFs (99% confidence bounds). Simulated hip abductor strengthening resulted in lower peak JCFs relative to pre-operative for all five patients at the hip (18.9–23.8 ± 16.5%) and knee (20.5–23.8 ± 11.2%). Four of the five patients had reductions at the ankle (7.1–8.5 ± 11.3%) and low back (3.5–7.0 ± 5.3%) with one patient demonstrating no change. The reduction in JCF at the hip joint and at joints other than the hip with hip abductor strengthening demonstrates the dynamic and mechanical interdependencies of the knee, hip and spine that can be targeted in early THA rehabilitation to improve overall patient function.
Examining the efficacy of DVD technology in COPD self-management education of rural patients

A pilot study (n = 41) was conducted to test the effects of three educational treatments (DVD vs. Pamphlet vs. DVD + Pamphlet) on health-related quality of life (HRQoL), COPD information needs and self-efficacy among a referred sample of Certified Federal Rural Health Clinic patients (mean age = 61.51 years ± 6.29 years; ~61% female) suffering from COPD using a randomly-assigned, multiple-group pretest-posttest design with a control group. A MANCOVA testing planned multivariate contrasts determined patients receiving a DVD reported statistically significant higher levels of lung-specific physical functioning as compared to patients receiving a Pamphlet. Additionally, DVD patients reported clinically significant improvements on two dimensions of lung-specific HRQoL. No such improvements occurred within the Pamphlet and Control groups. The provision of self-management education as compared to usual care, however, did not improve the outcome variables examined.
A mixed methods study of physical activity and quality of life in adolescents with Turner syndrome.

Women with Turner syndrome (TS) have a high morbidity from both medical and psychological conditions with a negative impact on quality of life (QoL). Physical activity is a modifiable behavior shown to reduce risk for these chronic medical and mental health conditions and enhance QoL in other populations. Limited research suggests that adolescents and women with TS are less likely to engage in or enjoy physical activity than peers. This mixed methods study aimed to document physical activity levels in a sample of youth with TS and explore how factors unique to TS contribute to and are affected by physical activity. A cross-sectional sample of 21 girls (12-21 years) with TS and their parents (n = 21) completed standardized questionnaires to quantify habitual physical activity (3-day physical activity recall) and QoL (PROMIS) and participated in individual interviews focused on their experience with physical activity. Quantitative and qualitative results were synthesized using a phenomenological mixed methods approach. Results indicate that our sample engaged in less physical activity than peers and only 19% met recommendations for 1 hr per day of moderate-to-vigorous physical activity. Parents reported significant problems with peer relationships and psychological stress, and peer relationships scores correlated with physical activity. Reported barriers to physical activity included physical and psychosocial complications related to TS as well as unique developmental considerations specific to adolescence. Quantitative and qualitative results supported that structured fitness options embedded into routines enhanced activity levels. Results were compiled into specific recommendations for clinical care and areas of future research.
Postpartum obsessive-compulsive disorder

Abstract This chapter describes a case of postpartum obsessive-compulsive disorder (PPOCD) in a mother 2 months post partum. PPOCD is described clinically and research is presented that makes a case for PPOCD being phenomenologically different from obsessive-compulsive disorder that occurs at other times in a woman's life. A proposed theoretic classification of PPOCD is described. Intrusive thoughts and obsessions that are common to PPOCD, including aggressive thoughts with avoidant behavior, are reviewed. The differential diagnosis between PPOCD and postpartum psychosis is made and pharmacologic and cognitive behavior treatment options are presented. The case details the presentation, treatment, and outcome in a new mother with comorbid depression and anxiety.
We Learn by Doing: Modeling Inclusive Pedagogy in a Graduate CS Ethics Course

While the need for undergraduate CS ethics education is well-established, less has been said about what graduate ethics education should look like. Graduate programs, particularly professional MS programs, present rich opportunities for modeling inclusivity and equity in education, enabling a sustainable continuation of CS ethics education. During our course, Ethical Considerations in Computing, graduate students learn to view the impact of their work through different lenses while exploring ideas around power and identity. A better understanding of ethical theories, particularly when mediated by women and other underrepresented people asserting their experiences, enables students to see how they can shape the CS culture, inside and outside the classroom. We argue that the intentionally inclusive and equitable course design that depicts ethics as something we ‘do’ rather than something we ‘know’, results in opportunities for broadening participation in computing beyond this course.
Access Control Model Extensions to Support Data Privacy Protection based on GDPR

The General Data Protection Regulation (GDPR) gives control of data to the data owner. It imposes several requirements and obligations on organizations that process and manage personal data of EU citizens. GDPR uses consent as a legal basis for personal data processing. We design a semantic model to represent GDPR consents; our model is explicit, understandable, and reusable. Ensuring that organizations comply with GDPR with respect to user consents is a critical issue. To address such an issue, we propose a Blockchain-based model for compliance verification. Our decentralized model ensures that only parties authorized based on users’ consent can access users’ data and that all activities are logged in an immutable distributed ledger. Our GDPR privacy protection framework is cast into the XACML reference architecture.
Initial Report of an Intradural Extramedullary Metastasis of a Pancreatic Neuroendocrine Tumor to the Cervical Spine: A Case Report and Review of the Literature

Background Pancreatic neuroendocrine tumors (pNETs) are known to frequently metastasize to the liver and lymphatics; however, metastasis to the spine is exceedingly rare. We report the first case of an intradural, extramedullary pNET metastasis to the upper cervical spine. Case Description A 75-year-old Hispanic male patient with history of stage IV pNET with metastasis to the liver and lymph nodes and new-onset lymphadenopathy seen on CT of the chest was found on positron emission tomography scan to have a lesion in the cervical spine. The patient was neurologically intact on physical examination, yet given the patient's medical history, magnetic resonance imaging of the cervical spine was performed, revealing a right-sided intradural, extramedullary mass at the C1–C2 level with associated mass effect on the spinal cord, likely representing a schwannoma. Due to the tumor size, mass effect, and the need for definitive tissue diagnosis, a partial C1–C2 laminectomy with intradural resection of the tumor was performed. The histology was consistent with the patient's known pNET. Conclusions As treatment for pNETs has evolved, there has been a surge in unique presentations of systemic well-differentiated pNETs being reported. It is vital that patients diagnosed with pNET be monitored for metastases, and when discovered, treated promptly.
Chapter 105 – Bartonella

The Bartonella genus has grown from a single member in the early 1990s (i.e., Bartonella bacilliformis), to 31 validated species at this writing. Eleven species are considered to be aetiologic agents of emerging or re-emerging infectious diseases of humans. The widespread occurrence of Bartonella in mammalian reservoirs ranging from bats to whales, together with a broad spectrum of potentially life-threatening disease manifestations in infected hosts, has stimulated considerable research to elucidate the molecular pathogenesis, epidemiology and genetics of these bacteria. Bartonella share several general attributes. They are small (approximately 0.3 µm in width by 1 µm in length), Gram-negative, pleomorphic coccobacilli with a genomic GC content of ~40%. Bartonellae are facultative intracellular pathogens that employ haemotrophy (infection of erythrocytes) as a parasitic strategy. As such, their growth in vitro can only be accomplished in media containing blood or haem supplements, and even then they are notoriously fastidious and slow-growing. Arguably one of the most remarkable observations is that virtually every type of mammal surveyed has been found to serve as a host and/or reservoir for a subset of Bartonella species. Moreover, transmission of these bacteria is usually vectored through haematophagous arthropod ectoparasites of the host.
Whole-Genome Sequence Typing shows extensive diversity of Listeria monocytogenes in the outdoor environment and poultry processing plants.

A reliable and standardized classification of Listeria monocytogenes (Lm) is important for accurate strain identification during outbreak investigations. Current whole-genome sequencing (WGS) based approaches for strain characterization either lack standardization, rendering them less suitable for data exchange, or are not freely available. Thus, we developed a portable and open-source tool Haplo-ST to improve standardization and provide maximum discriminatory potential to WGS data tied to an MLST (multi locus sequence typing) framework. Haplo-ST performs whole-genome MLST (wgMLST) for Lm while allowing for data exchangeability worldwide. This tool takes in (i) raw WGS reads as input, (ii) cleans the raw data according to user specified parameters, (iii) assembles genes across loci by mapping to genes from reference strains, (iv) assigns allelic profiles to assembled genes and provides a wgMLST subtyping for each isolate. Data exchangeability relies on the tool assigning allelic profiles based on a centralized nomenclature defined by the widely-used BIGSdb-Lm database. Tests on Haplo-STs performance with simulated reads from Lm reference strains yielded a high sensitivity of 97.5%, and coverage depths of [≥] 20x was found to be sufficient for wgMLST profiling. We used Haplo-ST to characterize and differentiate between two groups of Lm isolates, derived from the natural environment and poultry processing plants. Phylogenetic reconstruction showed sharp delineation of lineages within each group and no lineage-specificity was observed with isolate phenotypes (transient vs. persistent) or origins. Genetic differentiation analyses between isolate groups identified 21 significantly differentiated loci, potentially enriched for adaptation and persistence of Lm within poultry processing plants. IMPORTANCEWe have developed an open-source tool that provides allele-based subtyping of Lm isolates at the whole genome level. Along with allelic profiles, this tool also generates allele sequences, and identifies paralogs, which is useful for phylogenetic tree reconstruction and deciphering relationships between closely related isolates. More broadly, Haplo-ST is flexible and can be adapted to characterize the genome of any haploid organism simply by installing an organism-specific gene database. Haplo-ST also allows for scalable subtyping of isolates; fewer reference genes can be used for low resolution typing, whereas higher resolution can be achieved by increasing the number of genes used in the analysis. Our tool enabled clustering of Lm isolates into lineages and detection of potential loci for adaptation and persistence in food processing environments. Findings from these analyses highlights the effectiveness of Haplo-ST in subtyping and evaluating relationships among isolates for routine surveillance, outbreak investigations and source tracking.
Bi-paratopic and multivalent human VH domains neutralize SARS-CoV-2 by targeting distinct epitopes within the ACE2 binding interface of Spike

Neutralizing agents against SARS-CoV-2 are urgently needed for treatment and prophylaxis of COVID-19. Here, we present a strategy to rapidly identify and assemble synthetic human variable heavy (VH) domain binders with high affinity toward neutralizing epitopes without the need for high-resolution structural information. We constructed a VH-phage library and targeted a known neutralizing site, the angiotensin-converting enzyme 2 (ACE2) binding interface of the trimeric SARS-CoV-2 Spike receptor-binding domain (Spike-RBD). Using a masked selection approach, we identified 85 unique VH binders to two non-overlapping epitopes within the ACE2 binding site on Spike-RBD. This enabled us to systematically link these VH domains into multivalent and bi-paratopic formats. These multivalent and bi-paratopic VH constructs showed a marked increase in affinity to Spike (up to 600-fold) and neutralization potency (up to 1400-fold) on pseudotyped SARS-CoV-2 virus when compared to the standalone VH domains. The most potent binder, a trivalent VH, neutralized authentic SARS-CoV-2 with half-minimal inhibitory concentration (IC 50 ) of 4.0 nM (180 ng/mL). A cryo-EM structure of the trivalent VH bound to Spike shows each VH domain bound an RBD at the ACE2 binding site, explaining its increased neutralization potency and confirming our original design strategy. Our results demonstrate that targeted selection and engineering campaigns using a VH-phage library can enable rapid assembly of highly avid and potent molecules towards therapeutically important protein interfaces.
Initiative on Quality Shareholders Highlights

This Publication is part of The Quality Shareholder Initiative at the Center for Law, Economics and Finance (C-LEAF), at The George Washington University Law School, Prof. Lawrence A. Cunningham, Faculty Director. Highlights of a research initiative that formalizes the longstanding intuition that the sorts of shareholders a company attracts influences its performance. Contains lists of the best shareholders in corporate America, measured by long holding periods and high portfolio concentration, and lists of the companies that attract such shareholders in high density. Notes and explains how such shareholders and companies have been prone to outperform rivals. Explores what quality shareholders look for in companies and a dozen of the practices and policies that, evidence shows, companies can use to attract quality shareholders. Includes bibliographic references and suggestions for further research.
Machine learning suggests polygenic risk for cognitive dysfunction in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a multi-system disease characterized primarily by progressive muscle weakness. Cognitive dysfunction is commonly observed in patients; however, factors influencing risk for cognitive dysfunction remain elusive. Using sparse canonical correlation analysis (sCCA), an unsupervised machine-learning technique, we observed that single nucleotide polymorphisms collectively associate with baseline cognitive performance in a large ALS patient cohort (N = 327) from the multicenter Clinical Research in ALS and Related Disorders for Therapeutic Development (CReATe) Consortium. We demonstrate that a polygenic risk score derived using sCCA relates to longitudinal cognitive decline in the same cohort and also to in vivo cortical thinning in the orbital frontal cortex, anterior cingulate cortex, lateral temporal cortex, premotor cortex, and hippocampus (N = 90) as well as post-mortem motor cortical neuronal loss (N = 87) in independent ALS cohorts from the University of Pennsylvania Integrated Neurodegenerative Disease Biobank. Our findings suggest that common genetic polymorphisms may exert a polygenic contribution to the risk of cortical disease vulnerability and cognitive dysfunction in ALS.
Road Weary? Testing Whether Long Commutes to Testing Sites Explain Deficient Cyber Charter School Academic Performance.

Cyber charter schools may increase access to a range of educational offerings, but they substantially underperform traditional public schools on measured academic performance, as demonstrated in a ...
The Sharing Economy: State and Local Regulatory Coordination Needed

The article argues that uniform statewide regulations of the sharing economy should be rejected in favor of a coordinated state and local government regulatory approach. Governmental fragmentation at the local level in the United States results in the imposition of diverse regulations upon sharing economy activities taking place in a metropolitan area. States should resist the pressure to establish uniform statewide regulations over transactions that require municipal oversight due to their direct impact upon local residents such as congestion caused by picking up and dropping off ride-sharing passengers in heavily trafficked areas. States should empower municipalities to regulate the adverse externalities caused by the sharing economy in areas where regulatory uniformity is not necessary. State legislation can also establish minimum standards and authorize municipalities to supplement the minimum standards as they see fit. Another approach would be joint state and local agreements defining each party’s role in regulating certain sectors of the sharing economy The article suggests that a coordinated state and local approach could entail the implementation of sharing economy regulations on a metropolitan-wide or regional basis through (1) cooperative arrangements; (2) creation of a separate sharing economy coordinating entity with representatives from affected municipalities; (3) coordination through neighborhood councils or other civic associations; or (4) metropolitan planning organization (MPO) coordination, especially when the sharing economy activities affect a region’s transportation system.
Autoimmune Thyroid Disease and Psoriasis Vulgaris after COVID-19 in a Male Teenager

COVID-19 is implicated in triggering autoimmune, dermatologic, and thyroid diseases. We present a first known case of development of Graves' disease and psoriasis vulgaris in a previously healthy male teenager without any family history, diagnosed after COVID-19 infection. Evaluation of "long COVID syndrome" should include thorough history and thyroid evaluation.
Evaluating the effect of high-pressure processing in contrast to boiling on the antioxidant activity from alcalase hydrolysate of Great Northern Beans (Phaseolus vulgaris).

Food processing can alter protein structure, modulate enzyme accessibility, and therefore the release of bioactive peptides. Thus, processing techniques, boiling, high-pressure processing (HPP), and a combination of both, were compared for their efficiency to release antioxidant peptides after alcalase hydrolysis of Great Northern Beans (GNBs). The oxygen radical absorbance capacity (ORAC) indicated that boiled hydrolysates had the highest antioxidant activity (370.9 ± 43.8 µmol TEAC/g). Mass spectrometry-based analysis suggested that di- and tri-peptide expression were significantly altered among the three treatments, and either Ile, Leu, Phe, and Arg containing peptides potentially contributed toward the enhanced antioxidant activity. Furthermore, the total phenolic content of the HPP-treated hydrolysate was higher than the other two treatments, with ferulic acid being the most prominent phenolic compound present in the bean hydrolysates. This study indicates that thermal processing such as boiling is more effective in modulating the release of antioxidant peptides. PRACTICAL APPLICATIONS: Common beans (Phaseolus vulgaris), such as Great Northern Beans (GNBs) are one of the major pulse crops in the United States. Storage proteins in beans can release peptides with biological activities after enzymatic hydrolysis. However, processing conditions can modulate the release of peptides. The present study is primarily focused on comparing the two processing methods, boiling and HPP, and their combination for the generation of peptides with potential antioxidant activity in alcalase-digested GNBs. Data from the study suggest that thermal treatment such as boiling is more effective in modulating the release of peptides from alcalase hydrolysate of GNBs with antioxidant activity. This is particularly important because over different cultures around the world, boiling is the most widely used processing method for the cooking of beans, and hence, these data also ensure that boiling is the most effective method in getting the most beneficial effects from the consumption of beans.
Autopsy Education and Rate: Effect of the COVID-19 Pandemic

Autopsy training is required for board certification by the American Board of Pathology and may be affected by autopsy rate. It is unclear whether the COVID-19 pandemic has affected autopsy education and rate. Prior to the pandemic, our autopsy gross organ review lectures at the Brown University pathology residency program were in-person and used a detective style to discover the pathological lesions followed by an integrated discussion of anatomic and clinical pathology. During the COVID-19 pandemic, these lectures became remote and there was a noticeable impact on the involvement and responsiveness of the audience compared to in-person teaching. Certain qualities of face-to-face teaching can be difficult to be reproduced through virtual teaching, including the detective style to look for pathological lesions and the ability to palpate lesions from gross specimens. Our results showed that the autopsy case number increased during the COVID-19 pandemic, but the overall autopsy rate did not significantly change.
Prospective study of vaginal dilator use adherence and efficacy following radiotherapy

Abstract Background and purpose Vaginal stenosis (VS) after pelvic radiotherapy (RT) can impair long-term quality of life. We prospectively assessed adherence and efficacy of vaginal dilator (VD) use in women after pelvic RT. Material and methods Women with gastrointestinal ( n =63) and gynecologic ( n =46) cancers self-reported use and VD size in monthly diaries for 12months after radiotherapy. Adherence was measured as actual VD use out of recommended times over 12months (3×/week×52weeks=156). Results Among 109 participants, aged 28–81years (median, 58years), mean percent adherence over 12months was 42% (95% confidence interval [CI], 36–48%). Adherence was highest in the first quarter (56%), but fell to 25% by the fourth. Disease type, treatment sequence, and chemotherapy were predictors of adherence (all P P ⩽.05). Conclusion VD use is effective in minimizing VS, but adherence at 12months was poor. Studies evaluating methods of improving adherence and determining the optimal frequency and duration of use are needed.
Disaggregating the Impacts of Welfare Reform: Reflections on Five Studies

The five papers in this symposium advance the vital task of disaggregating the impacts of welfare reform. Four report differences across groups defined by location (rural or urban), types of TANF-eligible family, type of family structure, and race and ethnicity. The fifth reports few differences across race and ethnic groups. As our experience with TANF-style welfare grows and opportunities arise to reshape it, policy makers need to understand whether its impacts differ among subgroups, and why any differences exist. These studies provide useful points of departure for future research on these important policy issues.
Gender differences in substance use and initiation of sexual activity

Even though widespread efforts have focused on educating young adults about HIV and AIDS, many individuals continue to engage in behaviors that place them at risk. These behaviors include frequent experimentation with alcohol and other drugs prior to sex, engaging in sexual activity with different partners, and inconsistent safe sex practices (Butcher et al. 1991). The combination of these risky behaviors causes increased concern about the spread of HIV among those of college age. This study focused on two behaviors by examining the relationship between substance use during adolescence and early initiation of sexual activity in a sample of 950 subjects aged 19–21 in a mid-sized southern city. Results indicate that early use of alcohol and marijuana relates to earlier initiation of sexual activity and subsequent risky sexual behavior among young adults. Also, gender differences were observed for frequent users of marijuana and alcohol with males engaging in riskier sexual practices. Recommendations for interventions are made.
Hybrid Fuzzy-Genetic Approach Integrating Peak Identification and Spectrum Fitting for Complex Gamma-Ray Spectra Analysis

A novel hybrid approach for analysis of complex gamma-ray spectra of various origins is described and the test results using spectra obtained from a sodium iodide detector (NaI) are presented. This novel approach exploits the synergism of two artificial intelligence tools; fuzzy logic and genetic algorithms, where the two are merged to identify isotopes and their respective contribution in a given spectrum. The fuzzy logic module focuses on identifying isotopes in the spectrum, while the genetic algorithm (GA) fits and subsequently computes the fractional abundances of the identified isotopes. The fitting of the spectrum is controlled by an assessment procedure based on the test for significance of abundance coefficients, and on the computation of Theil coefficients. This unique synergism between fuzzy logic and GA presents a novel mechanism for automated selection of isotopes for use in spectrum fitting, and as a result eliminates manually-based fitting and/or user intervention. A variety of test cases–including NaI real measured spectra–are used to benchmark this new approach. In addition, the performance of the hybrid method is compared to the multiple linear regression (MLR) fitting approach, along with the combination of fuzzy logic with MLR. This comparison demonstrates a slight superiority of this novel approach regarding accuracy, precision and number of reported false detections.
Distinguishing between Directional Guidance and Motility Regulation in Neuronal Migration

Although neuronal migration is an essential process in development, how neural precursors reach their final destination in the nervous system is not well understood. Secreted molecules that are known to be involved in axon guidance are likely to play important roles in regulating neuronal migration, but an important issue that remains unclear is whether such molecules act as directional guidance cues or as motility regulators in neuronal migration. The secreted protein Slit was initially suggested to be a repellent for migrating neurons (Wu et al., 1999). However, it was concluded recently that Slit plays an inhibitory rather than a repulsive role in neuronal migration (Mason et al., 2001). We have developed a series of assays that allow us to differentiate between repulsive and inhibitory effects of secreted molecules, and we demonstrate that Slit is a repellent capable of reversing the direction of neurons migrating either in culture or in their native pathways. We also show that although Slit reduces migratory speed under certain conditions, it can function as a repellent without concurrent inhibition of neuronal migration. This is the first study to clearly demonstrate that migrating neurons can be directionally guided by secreted molecules. These findings provide a basis to understand the physiological roles of secreted molecules in the developing nervous system and have implications on how they could be applied therapeutically. Our results also indicate that it should be possible to determine the specific action of other molecules as directional guidance cues or as motility regulators of cell migration.
The Biological Clock Nucleus: A Multiphasic Oscillator Network Regulated by Light

The circadian clock nucleus of the mammalian brain is composed of thousands of oscillator neurons, each driven by the cell-autonomous action of a defined set of circadian clock genes. A critical question is how these individual oscillators are organized into an internal clock that times behavior and physiology. We examined the neural organization of the suprachiasmatic nucleus (SCN) through time-lapse imaging of a short-half-life green fluorescent protein (GFP) reporter of the circadian clock gene Period 1 (Per1). Using brain slice preparations, Per1 promoter rhythms were resolved at the level of the SCN, and in individual neurons within the SCN, to determine the temporal patterns of rhythmicity resulting from exposure of mice to light/dark cycle (LD) and constant darkness (DD) conditions. Quantitative imaging and patch-clamp electrophysiology were used to define the relationship of Per1 gene expression to neurophysiological output on an individual neuron basis. We found that in both LD and DD, the overall rhythm of the clock nucleus is composed of individual cellular rhythms that peak in distinct phase groups at 3-4 hr intervals. However, the phase relationships of Per1 oscillations to locomotor activity and the phase relationships among individual neuronal oscillators within the SCN are different in LD and DD. There was a positive, linear correlation of Per1 transcription with neuronal spike frequency output, thus Per1::GFP rhythms are representative of physiological rhythmicity. Our results reveal multiple phase groupings of SCN oscillators and suggest that light regulation of oscillator interactions within the SCN underlies entrainment to the photoperiod.
Vitamin C and Coronary Microcirculation

To the Editor: In their study on the short-term effects of vitamin C on coronary microcirculation, Kaufmann et al1 used adenosine to increase myocardial blood flow, which was assessed by positron emission tomography. When compared with controls, smokers showed an attenuated response that was corrected by 3 g of vitamin C given intravenously over 10 minutes. The authors conclude that cigarette smoke causes oxidant damage that is reversed by vitamin C. Unfortunately, the study conditions are not physiological, which is a consequence of the sigmoidal vitamin C dose-concentration relationship. When vitamin C is given orally, it is completely absorbed until the dose exceeds 200 mg.2 Consumption of 200 mg of vitamin C daily, which occurs in a typical Mediterranean diet, results in a plasma concentration of ≈70 μmol/L. Many cells, such as neutrophils, actively transport vitamin C and saturate before plasma. Saturation of cells by 70 μmol/L corresponds to the maximal velocity of the …
Goal Location Memory in Pigeons: Roles of the Hippocampal Formation and Visual Wulst

Verner P. Bingman, Ph.D., Advisor The abilities of homing pigeons (Columba livia) to navigate through unfamiliar territory and locate goals using visual cues have been well described. Recent recordings from single cells in the pigeon hippocampal formation (HF) also suggested that pigeons represent what happens at particular locations, that the HF is recruited in such representations, and that the right and left sides of HF participate differently in such representations. The present study examined if the hippocampal formation and a connected visual learning area, the Wulst, of homing pigeons were necessary for learning the contents of different goal locations in an open-field, laboratory environment. Results showed that while control animals were able to distinguish between two different goal locations, pigeons with bilateral hippocampal lesions were impaired at goal discrimination, even though feature cues could have been used to distinguish between goal locations. Unilateral HF lesions revealed that the right HF was more important for content learning than left HF. Wulst lesion pigeons also showed impaired content learning during training, but not testing. Of interest, probe data indicated that left HF and the Wulst were involved in associating multiple cues associated with goals, while right HF was not necessary for this type of learning. These results suggest a revised role for avian HF. HF, particularly right HF, serves an important role in memory for the contents of goal locations. Furthermore, the current results are suggestive of a role for avian HF in episodic-like memory, which includes memory for both the spatial and temporal context of events.
Observations of Branched-Chain Amino Acid Administration in Humans

Since the in vitro study of Buse and Reid in 1975 showing a stimulatory effect of leucine upon rat muscle protein synthesis and reduction in proteolysis, a similar effect has been sought in humans. In 1978, Sherwin demonstrated in humans an improvement in N balance with infusion of leucine in obese subjects fasting to lose weight. A variety of subsequent studies have been performed in humans where leucine alone or the BCAAs have been administered in varying amounts and durations, and the effect upon protein metabolism has been measured. Measurements of changes in muscle amino acid metabolism were made by arteriovenous difference measurements and by biopsies. An anabolic effect of leucine and the branched-chain amino acids (BCAAs) on reduction of muscle protein breakdown was found in these studies, with no measured effect upon muscle protein synthesis. Later studies using stable isotope tracers to define both whole-body protein turnover and leg or arm protein metabolism have similarly concluded that leucine administration specifically induces a reduction in protein breakdown without increasing protein synthesis. This anabolic effect, produced through a reduction of protein breakdown in vivo in humans by leucine is contrary to in vitro studies of rat muscle where stimulation of protein synthesis, has been demonstrated by leucine. Likewise an increase in protein synthesis has also been demonstrated by insulin in rat muscle that is not seen in humans. Of the various studies administering BCAAs or leucine to humans for varying periods of time and amount, the results have been consistent. In addition, no untoward effects have been reported in any of these studies from infusion of the BCAAs at upward 3 times basal flux or 6 times normal dietary intake during the fed portion of the day.
A 3D metal-organic network, [Cu2(glutarate)2(4,4′-bipyridine)], that exhibits single-crystal to single-crystal dehydration and rehydration

The reaction of Cu(NO3)2, glutaric acid and 4,4′-bipyridine in water affords a novel 3D coordination polymer which exhibits reversible desorption and adsorption of water molecules with retention of single crystallinity.
TRUTH WRONGED: CRISPIN WRIGHT'S TRUTH AND OBJECTIVITY

L'A. commente le livre «Truth and objectivity» elabore a partir des cours de Crispin Wright en 1991 en montant qu'a plus d'un egard il trahit la pensee de Wright. En particulier, il examine le traitement fait de l'«assertion» et de la reprise du debat entre realistes et anti-realistes sur la verite, dans une problematique sur le discours
Structural properties of hypertext

In this thesis, we provide a framework that allows the study of structural properties of hypertext using formal language theory. In formal language theory, a language is defined as a set of words over a set of abstract symbols, where words are concatenations of abstract symbols. We propose to view hypertext components that can link other hypertext components as abstract symbols and view the links as a way to substitute components with other components. With this view, the structure of hypertext becomes similar to the structure of the set of words in a language. More specifically, links on the set of hypertext components are viewed as a way to produce words over the set of hypertext components. Since grammars are a standard mechanism in formal language theory to describe a set of words, it is natural to use grammars to explain how hypertext is structured. This framework facilitates the possibility of investigating structural properties of hypertext using the well-studied field of formal language theory and may give new insights into fundamental questions about hypertext structure. Using this framework, this thesis develops a few basic theories regarding the structure of hypertext. We model hypertext as a transformation device (an a-transducer) that transforms a link-following into a sequence of matched pairs: basic linkable units. Then, we address the following questions: What can hypertext do? What structure is formed when a link-following is done? What structure is built when a virtual document is constructed? We show that the set of all link-followings in hypertext is a regular set. Then, we show that the set of all possible outputs of link-followings is context-free. This means that constructing virtual documents is essentially the same as generating words of a context-free language. There are practical implications of the current research. For example, we can utilize the “patterns” that exist in hypertext for developing a structural search mechanism. Also, automatic generation of the grammar of given hypertext could provide a useful new analysis technique for authors.
A Synergistic Text Compression Method-STCM

The method introduced in this article is a new approach to text compression that shows merit in a higher compression ratio, its ability to be integrated with existing utilities to augment their performance, and its resiliency to error introduced through bit corruption by limiting the error effect to only that word where the error occurred. The results introduced, based on a comprehensive evaluation of the proposed method with respect to existing utilities, demonstrate such merits and are provided in support of these assertions.
Detection of bacterial quorum sensing N-acyl homoserine lactones in clinical samples

Bacteria communicate among themselves using certain chemical signaling molecules. These signaling molecules generally are N-acyl homoserine lactones (AHLs) in Gram-negative bacteria and oligopeptides in Gram-positive bacteria. In addition, both Gram-positive and Gram-negative bacteria produce a family of signaling molecules known as autoinducer-2 that they employ for their communications. Bacteria coordinate their behavior by releasing and responding to the chemical signaling molecules present in proportion to their population density. This phenomenon is known as quorum sensing. The role of bacteria in the pathogenesis of several diseases, including gastrointestinal (GI) disorders, is well established. Moreover, rather recently bacterial quorum sensing has been implicated in the onset of bacterial pathogenicity. Thus, we hypothesized that the signaling molecules involved in bacterial communication may serve as potential biomarkers for the diagnosis and management of several bacteria-related diseases. For that, we previously developed a method based on genetically engineered whole-cell sensing systems for the rapid, sensitive, cost-effective and quantitative detection of AHLs in biological samples, such as saliva and stool, from both healthy and diseased individuals with GI disorders. Although various analytical methods, based on physical-chemical techniques and bacterial whole-cell biosensors, have been developed for the detection of AHLs in the supernatants of bacterial cultures, only a few of them have been applied to AHL monitoring in real samples. In this paper, we report work performed in our laboratory and review that from others that describes the detection of AHLs in biological, clinical samples, and report some of our recent experimental results.