cssi/SciSciGPT-SciSciNet huggingface dataset:
Evidence that spontaneous situs inversus in cultured neural plate staged rat embryos is additive with and not mediated through adrenergic mechanisms.

Approximately 50% of untreated presomite rat embryos in culture have demonstrated inversions of cardiac looping (laeval instead of dextral) or tail flexure (left-sided instead of right-sided), or both. This spontaneous situs inversus (SI) was not accompanied by growth inhibition or any other observable defects. The incidence of SI was directly related to the stage at dissection, and all heart defects and most flexure defects were eliminated by delaying explantation to the early somite stage. The incidence of SI was not lowered significantly either by removal of endogenous catecholamines from the culture serum by dialysis or by inclusion of α- or β-adrenergic antagonists in the medium
A rank-based empirical likelihood approach to two-sample proportional odds model and its goodness of fit

A rank-based empirical likelihood method is proposed and applied to estimate the proportionality parameter and the underlying distributions in a two-sample semiparametric proportional odds model. A distribution-free goodness-of-fit test for the model is also given. It is proved that the maximum likelihood estimator of the proportionality parameter is reciprocal symmetric. As one of the applications, we use the proposed procedure to estimate receiver operating characteristic (ROC) curves. We also perform a simulation study to assess the performance of the proposed procedure and provide a numerical example based on real-world data to illustrate the implementation of the method.
Mandatory reporting of healthcare-associated infections: A long way to go

BACKGROUND: In 2004, the Pennsylvania Health Care Cost Containment Council (PHC4) mandated that acute care hospitals in Pennsylvania report all healthcare-associated infections (HAIs) in hospitalized patients. The goal of PHC4 is to reduce the cost and improve the quality of healthcare through public reporting of healthcare outcomes, including HAIs. PHC4 requires the use of CDC definitions of HAI but does not specify a methodology to obtain this data. PHC4 utilizes both administrative and active surveillance data sources supplied by hospitals to assess the quality of HAI data submitted. Preliminary reports from PHC4 revealed significant discrepancies between data from these two sources. Objective: To determine the concordance between HAIs in hospitalized patients identified using administrative data to HAIs identified by active surveillance conducted by infection control professionals (ICPs). METHODS: This retrospective study was performed at a large children's hospital that conducts active surveillance of high-risk patient units. Using selected ICD-9 billing codes in predetermined positions on hospital discharge reports, PHC4 classifies four types of presumed HAI: 1) surgical site infections, 2) ventilator-associated pneumonia, 3) catheter-associated urinary tract infections, and 4) central line–associated bloodstream infections (CLABSIs). We compared HAIs identified by active surveillance to HAIs identified by PHC4 from hospital administrative data. Discrepancies were resolved by further chart review by ICPs. RESULTS: Active surveillance of targeted units over 9 months in 2004 identified 239 HAIs; administrative data identified 943 patients with presumed HAIs during the same period. 131 infections identified by active surveillance were not captured from administrative data; 842 presumed HAIs captured from administrative data were not identified by active surveillance. Upon further review, we found that 70% of HAIs identified by active surveillance alone were CLABSIs. We are conducting an audit of randomly selected records to resolve discrepancies and identify sources of error in this reporting mechanism. CONCLUSIONS: Public reporting of adverse healthcare events might reduce costs and improve patient outcomes. However, additional study is needed to define the optimal strategy for conducting surveillance for HAIs so that accurate and meaningful data are available to consumers.
Lack of Significant Interactions Between Clopidogrel and Proton Pump Inhibitor Therapy: Meta-Analysis of Existing Literature

Published data regarding the effect of concomitant clopidogrel and proton pump inhibitor (PPI) therapy on cardiovascular outcomes have been conflicting. To perform an updated meta-analysis in order to determine changes in risk differences (RD) between primary and secondary outcome analyses. Primary analysis was based on definite vascular outcomes, including all cause mortality, cardiac death, myocardial infarction, and/or stroke. Secondary analysis also incorporated probable cardiac events, which included re-hospitalization for cardiac symptoms or revascularization procedures. RD were combined using a random-effects model. We reviewed 1,204 publications of which 26 studies (16 published articles, 10 abstracts) met inclusion criteria. The meta-analysis of outcomes from the two randomized controlled trials did not show an increased risk (RD 0.0, 95% CI −0.01, 0.01) for adverse outcomes. The meta-analysis of primary outcomes showed a RD of 0.02 (95% CI 0.01, 0.03) for all studies. The meta-analysis for secondary outcomes yielded a RD of 0.02 (95% CI 0.01–0.04) based on 19 published papers and abstracts. When primary and secondary outcomes were combined, the meta-analysis for published papers yielded an overall RD of 0.05 (95% CI 0.03–0.06). In patients using concomitant clopidogrel and PPI therapy, the risk of adverse cardiac outcomes was 0% based on data from well-controlled randomized trials. Data from retrospective studies and the addition of probable vascular events significantly increased the RD estimates, likely due to lack of adjustment for potential confounders.
Carbamate Insecticides: Multisubstituted Chloro- and Methyl-Phenyl N-Methylcarbamates.

The toxicity of the six isomeric dichlorophenyl and dimethyl-phenyl N -methylcarbamates was evaluated to three species of insects and was compared with the anticholinesterase activity of the compounds. Numerous mixed chloro-methylphenyl N methylcarbamates were studied in a similar manner and the relationships of structure to biological activity are discussed. The substitution of the isosteric chlorine atom for the methyl group generally resulted in decreased biological activity.
Monads for incremental computing

This paper presents a monadic approach to incremental computation, suitable for purely functional languages such as Haskell. A program that uses incremental computation is able to perform an incremental amount of computation to accommodate for changes in input data. Recently, Acar, Blelloch and Harper presented a small Standard ML library that supports efficient, high-level incremental computations [1]. Here, we present a monadic variant of that library, written in Haskell extended with first-class references. By using monads, not only are we able to provide a purely functional interface to the library, the types also enforce "correct usage" without having to resort to any type-system extension. We also find optimization opportunities based on standard monadic combinators.This is an exercise in putting to work monad transformers with environments, references, and continuations.
Pushrim forces and joint kinetics during wheelchair propulsion

Abstract Objective: To investigate pushrim forces and joint kinetics during wheelchair propulsion and to discuss the differences between inexperienced and experienced wheelchair users. Design: Cohort study. Setting: Human engineering laboratory at a state university. Subjects: Four men who use manual wheelchairs for mobility and four nondisabled men who did not have extensive experience pushing a wheelchair; all subjects were asymptomatic for upper extremity pain or injury. Methods: Subjects pushed a commonly used wheelchair fitted with a force-sensing pushrim on a stationary wheelchair dynamometer. Video and force data were collected for 5 strokes at one speed of propulsion. Pushrim forces and net joint forces and moments were analyzed. Main Outcome Measures: Pushrim forces, radial (F r ) and tangential (F t ), were analyzed and compared for both groups in relation to peak values and time to peak values and as ratios of overall forces generated. Net joint forces and moments were analyzed in a similar fashion. Results: Pushrim forces and joint moments were similar to those previously reported, with radial forces averaging between 34 and 39N and tangential forces ranging on average between 66 and 95N. Tangential forces were higher than radial forces, and mean ratios of tangential forces to the resultant force were approximately 75%, whereas mean radial force ratios were approximately 22%. All subjects showed higher joint moments at the shoulder than at the elbow or wrist. A large component of vertical reaction force was seen at the shoulder. Significant differences ( p Conclusions: Discrete variables from the force-time curves can be used to distinguish between wheelchair users and nonusers. The experienced users tended to push longer, used forces with lower peaks, and took longer time to reach peak values. This propulsive pattern may have been developed to reduce the chance of injury by minimizing the forces at the joints, as a means of maximizing efficiency or as a combination of these factors. More work investigating 3-dimensional forces and the influence of seating position and various conditions of propulsion such as speed changes, ramps, and directional changes on injury mechanisms needs to be completed.
CD4 cell count as a surrogate endpoint in HIV clinical trials: a meta-analysis of studies of the AIDS Clinical Trials Group

Objective To evaluate initial changes in CD4 cell count as a surrogate endpoint for clinical outcome in HIV-infected patients. Design Meta-analysis of all relevant Phase II and III randomized clinical trials undertaken by the Adult AIDS Clinical Trials Group. Methods Individual patient data were obtained from each clinical trial, and the difference between a pair of treatments in their effect on clinical outcome (AIDS or death, or death alone) during 2 years of follow-up was evaluated. The proportion of treatment effect explained (PTE) was the proportion of this difference explained by the change in CD4 cell count 6 months after starting treatment, evaluated using proportional hazards models. A weighted average PTE across treatment comparisons was obtained. The association between the difference between treatments in clinical outcome, expressed as hazard ratio, and the difference in mean change in CD4 cell count was evaluated using regression analysis. Results There were 15 clinical trials involving 24 treatment comparisons. The weighted average PTE for both progression to AIDS or death was 0.16 [95% confidence interval (Cl), 0.07-0.26] and for death was 0.10 (95% Cl, 0.00-0.20). There were significant associations between treatment differences in effect on AIDS or death, and on death alone, and the difference in mean change in CD4 cell count. A difference in mean change in CD4 cell count of 30 or 40 x 10(6)/l or more in favor of the test treatment indicated with high probability that there was a corresponding difference in progression to AIDS or death. Conclusions The small PTE suggest that other mechanisms of drug action not captured by initial change in CD4 cells are important. CD4 cell count is a weak surrogate endpoint, but has some value as an aid for screening treatments for drug development or preliminary regulatory approval.
Moderate calorie restriction improves cardiac remodeling and diastolic dysfunction in the Dahl-SS rat.

Abstract Caloric restriction extends longevity and reduces the onset of chronic disease in many animal models. Recently, caloric restriction was shown in humans to be associated with lower blood pressure, decreased systemic inflammation, and improved cardiac diastolic parameters. However, the causation and mechanisms of caloric restriction were obscured by the varied diet composition of the participants. The Dahl salt-sensitive rat which develops gradual, hypertension-associated diastolic dysfunction was used in this study to assess the impact of caloric restriction upon decompensated pressure-overload hypertrophy. Male Dahl salt-sensitive rats were provided either a low-salt diet or a high-salt diet to initiate heart failure progression. A further subset of high-salt rats underwent 15% calorie restriction, with salt load held constant. Parameters measured included serial systolic blood pressure, body weight, and changes of left ventricular systolic and diastolic parameters and ventricular geometry by echocardiography. After 18 weeks, fasting glucose, blood lipids, heart weight, kidney weight, lung weight, plasma interleukin-6 and TNF-α, and cardiac lipid peroxidation were measured. Low-salt rats did not develop heart failure. While high-salt rats displayed features of decompensated pressure-overload hypertrophy, moderate calorie restriction remarkably reduced morbidity. Compared to the high-salt fed group, the high-salt, calorie-restricted group showed reduced blood pressure, delayed onset of cachexia, lower fasting hyperlipidemia, lower cardiac, renal and lung weight, less plasma IL-6 and TNF-α, less cardiac oxidative damage, and improved diastolic chamber function and cardiac index. Modest calorie restriction, independent of salt intake, reduced pathogenesis in this well described model of decompensated pressure-overload hypertrophy.
Characterization of divalent cation-induced [3H]acetylcholine release from EGTA-treated rat hippocampal synaptosomes.

Calcium-naive synaptosomes were used to assess the effects of divalent cations on [3H]acetylcholine release from rat hippocampal homogenates. Following equilibration with calcium-free buffer (containing 10μM EGTA), calcium reversibly increased [3H]acetylcholine efflux (up to five-fold) while causing no measurable efflux of lactate dehydrogenase. When substituted for calcium, strongtium and barium behaved similarly although barium exhibited three-fold greater efficacy. In the presence of elevated potassium, 4-aminopyridine or tetraethylammonium, the secretagogue efficacy of calcium (but not barium) was markedly increased. The release-promoting effects of both cations were inhibited by lanthanum, magnesium, cadmium, and ω-conotoxin but were insensitive to nifedipine and cobalt (both 10 μM). In addition, stimulation of muscarnic cholinergic autoreceptors substantially inhibited both calcium and barium-evoked [3H]acetylcholine release. Taken together, these results indicate that cation-evoked transmitter release from calcium-naive synaptosomes is subject to normal neuroregulatory mechanisms and therefore should be useful for investigating presynaptic modulation of neuronal exocytosis.
Aromatic–Proline Interactions: Electronically Tunable CH/π Interactions

Proline residues have unique roles in protein folding, structure, and function. Proline and the aromatic amino acids comprise the encoded cyclic protein residues. Aromatic protein side chains are defined by their negatively charged π faces, while the faces of the proline ring are partially positively charged. This polarity results from their two-point connection of the side chain to the electron-withdrawing protein backbone, and the lower electronegativity of hydrogen compared to carbon, nitrogen, and oxygen. The hydrogens adjacent to the carbonyl and amide nitrogen, Hα and Hδ, respectively, are the most partially positive. Proline’s side chain is also conformationally restricted, allowing for interaction with aromatic residues with minimal entropic or steric penalty. Proline and aromatic residues can interact favorably with each other, due to both the hydrophobic effect and the interaction between the π aromatic face and the polarized C–H bonds, called a CH/π interaction. Aromatic–proline interactions ca...
The problem of discrimination in health care priority setting.

Increasingly stringent fiscal restrictions on the scope of medical services available to patients have resulted in calls for explicit health care priority setting. Several commentators have called for the application of decision-analytic principles to such efforts, which would assign services priority based on the extent to which they produce preferred health outcomes. The Oregon Medicaid exercise is an example of such a process. An important challenge to these utilitarian efforts is the need to avoid discrimination against people with medical disabilities. Both of the key elements entailed by decision-analytic approaches to priority setting—estimation of outcomes and assignment of values to those outcomes—are vulnerable to charges of discrimination, primarily because both the medical outcomes expected in disabled individuals and the values they place on those outcomes may differ from the general public. Priority-setting efforts must proceed carefully to avoid the appearance (and reality) of discrimination. ( JAMA . 1992;268:1454-1459)
Phase behavior of aqueous solutions containing nonionic surfactant-polyethylene glycol mixtures

The phase separation behavior of two nonionic surfactants, polyoxyethylene (10) oleyl ether (I) and polyoxyethylene (10) cetyl ether (II), was examined in solutions containing polyethylene glycols (PEGs) of various molecular weights. It was found that PEGs decrease the cloud points of both surfactants, and that this decrease is dependent upon the concentration and molecular weight of the PEG. This effect of PEGs on the cloud point can be explained by a depletion flocculation mechanism, which results in a segregative phase separation of the solution into surfactant-rich and polymer-rich phases. The Krafft point of II increased in the presence of PEGs, and this increase was dependent on the concentration of PEG, but independent of its molecular weight.
Particle clustering due to hydrodynamic interactions

Dynamic simulations of an isotropic suspension of particles in a viscous gas are performed. The energy in the suspension decays with time as a result of viscous dissipation in the gas. The rate of viscous dissipation in sufficiently energetic suspensions, those with a high Stokes number, is consistent with the theory of Sangani et al. [J. Fluid Mech. 313, 309–341 (1996)] for homogeneous hard-sphere suspensions. As the suspension loses energy, the dissipation rate decreases dramatically and the particles cluster as indicated by the presence of many more near neighbors than would be found in a hard sphere distribution.
Minimum-state sequential circuits for a restricted class of incompletely specified flow tables

This paper is concerned with the problem of obtaining minimum-state sequential circuits for incompletely specified flow tables. Attention is directed to relay-type flow tables in which the only unspecified entries are those which occur because of restrictions on the allowed input-variable changes. For this type of flow table it is shown that a simplified version of the Unger-Paull procedure is sufficient. In particular, only maximum compatibles need be considered in forming the minimum-state sequential circuit.
Racial and ethnic variation in partner perspectives about the breast cancer treatment decision-making experience.

PURPOSE/OBJECTIVES To characterize the perspectives of partners (husbands or significant others) of patients with breast cancer in the treatment decision-making process and to evaluate racial and ethnic differences in decision outcomes. DESIGN A cross-sectional survey. SETTING Los Angeles, CA, and Detroit, MI. SAMPLE 517 partners of a population-based sample of patients with breast cancer four years post-treatment. METHODS A self-administered mailed questionnaire. Chi-square tests and logistic regression were used to assess associations between race and ethnicity and decision outcomes. MAIN RESEARCH VARIABLES Decision regret and three elements of the decision process: information received, actual involvement, and desired involvement. FINDINGS Most partners reported receiving sufficient information (77%), being involved in treatment decisions (74%), and having sufficient involvement (73%). Less-acculturated Hispanic partners were more likely than their Caucasian counterparts to report high decision regret (45% versus 14%, p<0.001). Factors significantly associated (p<0.05) with high decision regret were insufficient receipt of treatment information, low involvement in decision making, and a desire for more involvement. CONCLUSIONS Partners were generally positive regarding their perspectives about participating in the breast cancer treatment decision-making process. However, less acculturated Hispanic partners were most vulnerable to decision regret. In addition, high decision regret was associated with modifiable elements of the decision-making process. IMPLICATIONS FOR NURSING Attention should be paid to ensuring racial and ethnic minority partners are sufficiently involved in breast cancer treatment decisions and receive decision support.
Preliminary observations on transplanting and a phenological index of seagrasses

Abstract Transplanting of seagrasses is a technique used to gain basic biological information on environmental tolerances to changes and extremes of water temperature and salinity, substrate, and chemical pollutants. Reciprocal transplants across tidal zones in one area or across latitudinal distances can be used to distinguish whether responses represent phenotypic plasticity or ecotypic differentiation. Transplanting also represents the ability to maintain, create, or recreate seagrass meadows in an inshore coastal environment where human activity is increasing, often with inimical effects on the marine environment. A variety of transplanting techniques have been developed, using vegetative and sexual stages of tropical and temperate North American seagrasses. Some show preliminary promise of successful transplanting. It is important to know the phenology of seagrasses used in transplanting. A preliminary phenological index is given. By identifying a phenological index and correlating stages with a planting method best suited for the stage, it should become possible to ensure the greatest possible use of the seagrass ecosystem with the least adverse effects.
Radical abdominopelvic lymphadenectomy: Historic perspective and current role in the surgical management of rectal cancer

Radical abdominopelvic lymphadenectomy for rectal cancer is based on the tenet that removal of all potentially involved lymphatic tissue will yield a lower rate of locoregional failure and improve survival. At centers with extensive experience with the procedure, the operating time is only modestly prolonged compared with conventional resection. Blood loss and postoperative hospitalization are not significantly increased. Urinary dysfunction and impotence associated with radical abdominopelvic lymphadenectomy (as high as 80 percent and 76 percent, respectively, in recent series) have been major deterrents to its more routine application. Preservation of the hypogastric plexus and even selective preservation of a unilateral S4 nerve root have been shown to reduce the occurrence of genitourinary complications. Improved five-year survival of 68 percent and local recurrence rates of 5 to 20 percent for TNM Stage III cancers have been achieved with radical abdominopelvic lymphadenectomy. These results compare favorably with recent trials of adjuvant chemoradiation after conventional resection in stage-matched patients. The rationale, evolution, and application of radical abdominopelvic lymphadenectomy to the surgical management of rectal cancer are critically examined. The potential benefits of radical abdominopelvic lymphadenectomy, which have been demonstrated in nonrandomized trials, should be evaluated in a prospective and properly randomized study to clearly establish or refute its efficacy.
The Drosophila gap gene network is composed of two parallel toggle switches.

Drosophila “gap” genes provide the first response to maternal gradients in the early fly embryo. Gap genes are expressed in a series of broad bands across the embryo during first hours of development. The gene network controlling the gap gene expression patterns includes inputs from maternal gradients and mutual repression between the gap genes themselves. In this study we propose a modular design for the gap gene network, involving two relatively independent network domains. The core of each network domain includes a toggle switch corresponding to a pair of mutually repressive gap genes, operated in space by maternal inputs. The toggle switches present in the gap network are evocative of the phage lambda switch, but they are operated positionally (in space) by the maternal gradients, so the synthesis rates for the competing components change along the embryo anterior-posterior axis. Dynamic model, constructed based on the proposed principle, with elements of fractional site occupancy, required 5–7 parameters to fit quantitative spatial expression data for gap gradients. The identified model solutions (parameter combinations) reproduced major dynamic features of the gap gradient system and explained gap expression in a variety of segmentation mutants.
Oxygen isotopic composition of soil water: Quantifying evaporation and transpiration

Abstract The oxygen isotopic composition of soil water provides an extra quantitative dimension in water balance analysis which allows separation of evaporation from transpiration. Spatial and temporal variations in water content and oxygen isotopic composition in soils along an arid to humid transect in Hawaii reflect the processes of recharge by rain, mixing with antecedent moisture, and evapotranspiration. Rainwater is always more depleted in 18O than is the soil water with which it mixes. Input of 18O-depleted rain increases volumetric water content while lowering the soil-water δ18O value. Evapotranspiration occurs continuously, leading to a decrease in the volumetric water content and an increase in the soil-water δ18O value. These effects are most pronounced at the soil surface and decrease in a downward direction. The frequency of recharge determines temporal variability of these values within a given depth interval, while differences along the transect are due to climatic parameters. Results of a material balance model indicate that evaporation decreases, transpiration increases, and the ratio of evaporation to transpiration decreases with increasing annual rainfall and decreasing temperature.
Characterization of a radio-frequency glow discharge/time-of-flight mass spectrometer

A radio-frequency glow discharge/time-of-flight mass spectrometer (RFGD-TOFMS) has been developed by simple modification of the interface to an ICP-TOFMS. The work described here evaluates the interface and operating conditions of the RFGD-TOFMS. The ion optics which focus ions toward the entrance of the TOFMS are the same as those used in the original ICP-TOFMS instrument. By means of pin-shaped brass samples of varied lengths, the sample-skimmer distance in the RFGD-TOFMS has been optimized at 4 mm. The discharge pressure and power have been found to be optimal at 50-60 W and 0.3 Torr, respectively. The application of small negative potentials to the skimmer cone (extraction orifice) was found to improve signals marginally. However, higher negative potentials reduced both signal levels and resolving power. The skimmer potential also affects the final kinetic energy of the ions before their extraction into the TOFMS. At 0.3 Torr all ions extracted for mass analysis have approximately the same kinetic energy, which can be estimated in the orthogonal TOFMS. Detection limits for several standard samples are at the single-ppm level, which is not unexpected; with the same ion-optical system, the current ICP-TOFMS also produces detection limits that are 2-3 orders of magnitude worse than those of many commercial instruments.
Sinonasal undifferentiated carcinoma with intracranial extension.

Aim: To report our experience in the management of sinonasal undifferentiated carcinoma (SNUC) over a period of 15 years. Study design: A retrospective case review of 13 patients with SNUC treated at the University of California, Davis, Medical Center (UCDMC) Center for Skull Base Surgery, over the past 15 years. Results: Most tumors arose in the ethmoid sinuses. All but 1 patient had a combined intracranial-extracranial resection through the anterior fossa-transcranial route and postoperative irradiation. The 13th patient had a transfacial subcranial approach. There are 6 who have survived free of disease at 14 years' to 8 months' follow-up. The average follow-up was 6 years, 3 months. One patient died of a pulmonary embolism in the first postoperative week, a second died of a bowel infarction 3 months postoperatively. Three patients died of their disease at 20, 18, and 8 months postoperatively: 1 with local recurrence and distant metastasis and the other 2 with local control but distant disease. The 6 survivors are at 8, 20, 28, 62, 84, and 105 months. Conclusion: SNUC is a rare malignancy of the paranasal sinuses with a poor prognosis. Radical surgery and adjunctive therapy can achieve good survival in a significant proportion of patients who would hitherto have seemed incurable.
Antibrain antibodies of the 19S gamma-globulin type in rats with allergic encephalomyelitis.

IT is known that complement-fixing antibrain antibodies can be detected in rats and other animals with allergic encephalomyelitis following sensitization to nervous tissue plus Freund's adjuvant1. Although these complement-fixing antibrain antibodies fix complement with autologous brain antigen2, failure to transfer passively allergic encephalomyelitis with immune serum and the lack of correlation between antibody titre and occurrence of disease in individual animals have left the role of such antibodies undefined1,3. This communication summarizes additional studies which indicate that complement-fixing antibrain antibodies in rats appear to belong to 19S-type γ-globulins and are incapable of giving passive cutaneous anaphylaxis.
Optical degeneracies in anisotropic layered media: Treatment of singularities in a 4×4 matrix formalism

4\ifmmode\times\else\texttimes\fi{}4 matrices have been used extensively to study the propagation of light in anisotropic layered systems whose principal optic axes have arbitrary orientation. We present a general theory for the propagation of light in arbitrarily anisotropic layered systems that is particularly suited for treating optical degeneracies that arise (1) when light propagates in an isotropic medium embedded within the anisotropic layers or (2) when light propagates along one of the optic axes in an anisotropic layer. Boundary conditions are applied explicitly to the electric and magnetic fields at each interface, and transfer matrices that relate the transmitted and reflected fields to the optical properties of the system are developed. Criteria are given for identifying the mathematical singularities caused by the degeneracies described above, and a method for treating the singularities in the relevant expressions is presented.
Microchemostat array with small-volume fraction replenishment for steady-state microbial culture

A chemostat is a bioreactor in which microorganisms can be cultured at steady-state by controlling the rate of culture medium inflow and waste outflow, thus maintaining media composition over time. Even though many microbial studies could greatly benefit from studying microbes in steady-state conditions, high instrument cost, complexity, and large reagent consumption hamper the routine use of chemostats. Microfluidic-based chemostats (i.e. microchemostats) can operate with significantly smaller reagent consumption while providing accurate chemostatic conditions at orders of magnitude lower cost compared to conventional chemostats. Also, microchemostats have the potential to significantly increase the throughput by integrating arrays of microchemostats. We present a microchemostat array with a unique two-depth culture chamber design that enables small-volume fraction replenishment of culture medium as low as 1% per replenishment cycle in a 250 nl volume. A system having an array of 8 microchemostats on a 40 × 60 mm(2) footprint could be automatically operated in parallel by a single controller unit as a demonstration for potential high throughput microbial studies. The model organism, Saccharomyces cerevisiae, successfully reached a stable steady-state of different cell densities as a demonstration of the chemostatic functionality by programming the dilution rates. Chemostatic functionality of the system was further confirmed by quantifying the budding index as a function of dilution rate, a strong indicator of growth-dependent cell division. In addition, the small-volume fraction replenishment feature minimized the cell density fluctuation during the culture. The developed system provides a robust, low-cost, and higher throughput solution to furthering studies in microbial physiology.
Predictors of driving outcome after traumatic brain injury

Abstract Coleman RD, Rapport LJ, Ergh TC, Hanks RA, Ricker JH, Millis SR. Predictors of driving outcome after traumatic brain injury. Arch Phys Med Rehabil 2002;83:1415-22. Objective: To examine predictors of driving status and fitness to drive after traumatic brain injury (TBI). Design: Retrospective and prospective follow-up of a cohort ranging from 4 months to 10 years post-TBI. Setting: A Midwestern, urban university-affiliated rehabilitation hospital. Participants: Seventy-one pairs of adults who had sustained a TBI and their significant others. Interventions: Not applicable. Main Outcome Measures: Driving status (whether the patient resumed driving), driving frequency (estimated miles driven per week), and postinjury driving records compiled by the Department of Motor Vehicles. Results: Logistic and hierarchical regression analyses indicated that the significant other's perceptions of the patient's fitness to drive were the strongest predictor of patients' driving status and driving frequency. However, years postinjury, disability at discharge, and current neuropsychologic functioning best predicted postinjury driving safety as measured by actual incidents. The relation between perception of patients' fitness and actual driving incidents, however, was modest. Conclusions: Neuropsychologic and medical information available by traditional methods showed unique value in predictive driving safety. However, caregiver perception of patients' fitness was the overwhelming determinant of whether and how much patients drive. The bases on which caregivers form their opinions affect the safety of patients and the public. The rehabilitation setting is a unique resource for family education regarding abilities essential to safe driving. © 2002 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation
Structure of a Magnetohydrodynamic Shock Wave in a Plasma of Infinite Conductivity

The structure of a magnetohydrodynamic perpendicular shock wave (magnetic field perpendicular to the direction of propagation) in a plasma of infinite conductivity has been analyzed. For the nonmagnetic case, the width of the shock front is found to be larger than in a non-ionized gas. Further, the width of the shock (in terms of mean free path within the shock) as a function of the shock strength as determined from the Stokes-Navier equations (which applies to weak shocks) is found to join smoothly at $M\ensuremath{\simeq}1.3$ with the same function as derived from the Mott-Smith analysis (which applies to strong shocks). The magnetic field tends to make the shock front narrower for shocks of moderate strength. It does not have appreciable effect for strong shocks.Application of the above results to solar radio noise and current theories of the origin of cosmic rays is indicated.
Effects of crack closure on fatigue crack-growth predictions for 2024-T351 aluminum alloy panels under spectrum loading

Abstract Effects of plasticity induced crack closure on the calculated fatigue crack-growth behaviour of middle-crack tension specimens made of 2024-T351 alloy subjected to variable amplitude fatigue loading were examined. The specified loadings were four distinct aircraft spectra: (1) “modified” center-wing spectrum performed as part of this study; (2) fighter aircraft maneuver spectrum; (3) lateral gust spectrum; and (4) pressurized fuselage gust and maneuver spectrum. The experimentally observed crack-growth lives were compared with crack-growth predictions obtained using the crack closure concept in FASTRAN. Fatigue crack-growth material data extracted from the NASGRO materials database and the literature follows two distinct paths possibly due to different transitions from flat-to-slant (single or double shear) fracture. The material baselines for the FASTRAN code were selected to fit the two different paths. The two baseline curves were used to predict crack-growth life under four spectra to assess how the observed differences in the crack-growth rate trajectories affect the results. Using the lower bound baseline curve, which is suspected to be characterized by the double shear fracture mode, the FASTRAN model was able to predict crack- growth behaviour within ±25% of the test data for all four spectra.
Vinculin–actin interaction couples actin retrograde flow to focal adhesions, but is dispensable for focal adhesion growth

In migrating cells, integrin-based focal adhesions (FAs) assemble in protruding lamellipodia in association with rapid filamentous actin (F-actin) assembly and retrograde flow. How dynamic F-actin is coupled to FA is not known. We analyzed the role of vinculin in integrating F-actin and FA dynamics by vinculin gene disruption in primary fibroblasts. Vinculin slowed F-actin flow in maturing FA to establish a lamellipodium–lamellum border and generate high extracellular matrix (ECM) traction forces. In addition, vinculin promoted nascent FA formation and turnover in lamellipodia and inhibited the frequency and rate of FA maturation. Characterization of a vinculin point mutant that specifically disrupts F-actin binding showed that vinculin–F-actin interaction is critical for these functions. However, FA growth rate correlated with F-actin flow speed independently of vinculin. Thus, vinculin functions as a molecular clutch, organizing leading edge F-actin, generating ECM traction, and promoting FA formation and turnover, but vinculin is dispensible for FA growth.
Extension table built-ins for Prolog

The ET* algorithm is a complete evaluation strategy for Datalog programs, which are logic programs without function symbols. The ET* algorithm uses extension tables and depth-first iterative deepening to provide the evaluation of pure function-free logic programs as declarative specifications. Extension tables are a memo facility that the algorithm uses both to cut infinite derivation paths for complete evaluation and to optimise the evaluation of logic programs. The original implementation of the ET* algorithm incorporated extension tables as part of the Prolog database using the built-in predicates assert and retract. The advantage of implementing the extension table using the Prolog database is the portability of the ET* algorithm. There are several disadvantages, however, with this approach. One disadvantage is the cost associated with the built-in predicates assert and retract, which are known to be expensive operations in most current Prolog systems. Another disadvantage is the differences across implementations in the semantics that these built-ins provide for dynamic predicates. This paper presents an efficient implementation of extension tables as a global data structure in Prolog, which includes a set of built-in primitives for manipulating the extension table. The ET* algorithm is updated to reflect the utilisation of the global extension table data structure. The implementations of the ET* algorithm are compared using time and space performance on a variety of benchmark programs.
Indices of changes in adiposity in American Indian children

Abstract Background Pathways, a randomized trial, evaluated the effectiveness of a school-based obesity prevention program on body composition changes in American Indian children. Several body composition methods were compared in intervention and control schools for assessing body composition changes. Methods Body composition methods, including skinfolds, bioelectric impedance analysis (BIA), body mass index (BMI), and using a combination of body composition methods were selected to assess 3-year changes in PBF in 705 children within 21 intervention schools and 663 children within 20 control schools. The study equation using skinfolds, BIA, and BMI was developed on a previous sample of American Indian children using deuterium oxide dilution as the criterion method. Results Body fat changes among methods for the intervention sample ranged from 5.4% (BMI method) to 7.1% (combination of methods) and for the control sample, from 5.8% (BMI method) to 7.3% (combination of methods). The study equation estimates were significantly higher than the other methods and the BMI equation estimates were significantly lower than the other methods except by BIA. The BIA equation showed a significantly larger standard deviation of the difference over the 3-year intervention than each of the other methods indicating less reliability for detecting body composition changes. Conclusions Within the Pathways large scale intervention trial with American Indian children, we found comparable yet significantly different mean PBF changes among methods. However, BIA was not as reliable as skinfolds and the combination of BIA, skinfolds, and body weight in assessing PBF changes.
Central sites and mechanisms involved in the hypothermic effects of dopamine in the rat

Abstract 1. 1.|Central injections of dopamine (50–600 μm) induce a dose dependent hypothermic response in the rat, with lateral ventricular injections being much more effective than those into the rostral hypothalamus. 2. 2.|Tolerance develops to this hypothermic response. 3. 3.|The hypothermia following lateral ventricular injections of dopamine in the morphine dependent rat can be blocked by injection of pimozide systemically, into the lateral ventricle or into the rostral hypothalamus. 4. 4.|Behavioral thermoregulatory responses indicate that the hypothermia is due to a lowering of the set point of the central thermostats.
A theoretical and experimental investigation of the relationships between metabolic rate, body size, and oxygen exchange capacity.

Abstract The influence of body size upon the decrease in weight-specific metabolic rate of organisms with increasing size is discussed. It is suggested that metabolic rate is closely correlated with, and perhaps dependent upon, the ability of an organism to obtain oxygen from the external environment. A model is presented that illustrates the advantage of having a decreasing weight-specific metabolic rate with increasing body size, rather than a linear relationship between the two. Support for the model is presented in the form of a literature review and with experimentation conducted with the aquatic salamander Siren lacertina .
Parental Issues and Perspectives Involving Mathematics Education in Elementary and Middle School Settings

Abstract This article reports on the initial findings of a three-year study funded through New York City's Department of Education Title IIA Professional Development under the No Child Left Behind Act of 2001 that investigated parental issues and perspectives involving mathematics education in elementary and middle school settings. A sample population of 790 parents of children in 1st through 8th grades, were surveyed to gather information about their needs and the needs of their children concerning school mathematics. The findings of this study are shared to help deepen the knowledge base and make it accessible to administrators, teachers, and teacher educators to inform them about parental concerns and ways to involve parents in the mathematics learning community. Efforts to involve parents are a necessary component to successful mathematics education reform. This study seeks to build upon current research and help strengthen the ways we include parents in their children's learning of mathematics.
The Limits of Judicial Independence: A Model with Illustration from Venezuela under Chávez

This paper presents a heuristic model of judicial independence that illustrates how it is that changes in de facto judicial independence may occur, even in the absence of overt institutional changes in de jure protections. The model is illustrated by the marked decline in the independence of Venezuela's high court between 1998 and 2010, under President Hugo Chavez. Focusing on the trade-off that courts face between jurisprudential change and policy change, the paper demonstrates how courts – even those that closely mirror the executive branch's policy preferences – may enter into conflict with dominant executives, and find their judicial independence restricted by informal means.
Authentication of sensor network flooding based on neighborhood cooperation

Flooding-based information dissemination is an important communication activity in sensor networks. Security is a major concern in sensor network flooding; in particular, the authentication of sensor nodes is important because once a node is compromised, it can send fake message to the network. One solution to this problem is to set up a base station that manages the authentication of all the sensor nodes. We propose a new authentication method that is intended for use in the absence of a trusted base station. The proposed method, referred to as predistribution-and-local-collaboration-based Merkle tree authentication (PCMA), combines Merkle tree authentication with neighborhood collaboration. We analyze the effectiveness of PCMA in term of the probabilities of nodes being compromised and disabled by an attacker. We also estimate the additional computation and energy required for this scheme. Finally, we present simulation results to validate our analysis
Defusing the Childhood Vocabulary Explosion

During the second year of life, the rate at which children acquire new words accelerates dramatically. This has led the field of language acquisition to posit specialized mechanisms that leverage the few words learned in the initial slow phase for faster vocabulary growth later. Simulations and mathematical analysis demonstrate that specialized cognitive changes are unnecessary. The acceleration in lexical acquisition is a necessary by-product of learning if (i) multiple words are learned in parallel and (ii) words are distributed such that there are few words that can be acquired quickly and many difficult ones.
Probing the Mechanisms of the Biological Intermolecular Transfer of Reduced Flavin

NAD(P)H-flavin oxidoreductases [flavin reductases (FR)] are a class of enzymes capable of producing reduced flavin for bacterial bioluminescence and other biological processes. Bacterial luciferase utilizes oxygen, reduced FMN (FMNH 2 ) and a long-chain aliphatic aldehyde as substrates for light emission. The Vibrio harveyi luciferase and FRP (for which we have cloned the gene and determined the crystal structure) is a model for the elucidation of the reduced flavin transfer mechanism using both a flavin reductase single-enzyme assay monitoring the NADPH oxidation and a flavin reductase-luciferase coupled assay measuring bioluminescence intensity or quantum output. The FRP exhibits a ping-pong kinetic pattern in the single-enzyme assay but changes to a sequential pattern in the coupled assay. Furthermore, FMN at >2 × 10 -6 mol/L reduced both the light intensity and quantum yield of the coupled reaction by noncompetitively inhibiting NADPH and competitively inhibiting luciferase. These results support a scheme in which the luciferase forms specific complex(es) with FRP. Indeed, such complexes were shown by fluorescence anisotropy to exist between luciferase and monomeric FRP either in the holo- or apoenzyme form. Furthermore, the reduced flavin cofactor of FRP is transferred directly to luciferase for bioluminescence, whereas the reduced flavin product of FRP is inefficient in supporting the luminescence reaction. The mechanism of reduced flavin transfer is apparently flavin and flavin reductase specific.