cssi/SciSciGPT-SciSciNet huggingface dataset:
Surface-Bound Proteins with Preserved Functionality

Biocompatibility of materials strongly depends on their surface properties. Therefore, surface derivatization in a controllable manner provides means for achieving interfaces essential for a broad range of chemical, biological, and medical applications. Bioactive interfaces, while manifesting the activity for which they are designed, should suppress all nonspecific interaction between the supporting substrates and the surrounding media. This article describes a procedure for chemical derivatization of glass and silicon surfaces with polyethylene glycol (PEG) layers covalently functionalized with proteins. While the proteins introduce the functionality to the surfaces, the PEGs provide resistance against nonspecific interactions. For formation of aldehyde-functionalized surfaces, we coated the substrates with acetals (i.e., protected aldehydes). To avoid deterioration of the surfaces, we did not use strong mineral acids for the deprotection of the aldehydes. Instead, we used a relatively weak Lewis acid for conversion of the acetals into aldehydes. Introduction of α,ω-bifunctional polymers into the PEG layers, bound to the aldehydes, allowed us to covalently attach green fluorescent protein and bovine carbonic anhydrase to the surfaces. Spectroscopic studies indicated that the surface-bound proteins preserve their functionalities. The surface concentrations of the proteins, however, did not manifest linear proportionality to the molar fractions of the bifunctional PEGs used for the coatings. This finding suggests that surface-loading ratios cannot be directly predicted from the compositions of the solutions of competing reagents used for chemical derivatization.
The Epidemiology of DSM-IV Panic Disorder and Agoraphobia in the United States: Results From the National Epidemiologic Survey on Alcohol and Related Conditions

Objective To present nationally representative data on the prevalence, correlates, and comorbidity of DSM-IV panic disorder (PAN), including the differentiation between panic with agoraphobia (PDA) and without agoraphobia (PDWA) and agoraphobia without a history of panic disorder (AG). Method The data were derived from the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (N = 43,093). Prevalence, correlates, and comorbidity of PAN, PDA, and PDWA with Axis I and II disorders were determined. Results Prevalences of 12-month and lifetime PAN were 2.1% and 5.1%. Rates of 12-month and lifetime PDWA were 1.6% and 4.0%, exceeding those of 12-month (0.6%) and lifetime (1.1%) PDA. Rates of 12-month and lifetime AG were extremely low, 0.05% and 0.17%. Being female, Native American, middle-aged, widowed/ separated/divorced, and of low income increased risk, while being Asian, Hispanic, or black decreased risk for PAN, PDA, and PDWA. Individuals with PDA were more likely to seek treatment and had earlier ages at onset and first treatment, longer episodes, and more severe disability, impairment, panic symptomatology, and Axis I and II comorbidity than those with PDWA. Conclusion PDA may be a more severe variant of PAN. Overrepresentation of PDA in treatment settings reflects increased treatment seeking and the severity of PDA relative to PDWA. The very low prevalence of AG leaves open questions about the meaning of the disorder as a distinct clinical entity as defined in the DSM-IV.
Habitat characteristics of bluntnose flyingfish Prognichthys occidentalis (Actinopterygii, Exocoetidae), across mesoscale features in the Gulf of Mexico

The aim of the present study is to investigate the influence of oceanic features on the distribution and abundance of bluntnose flyingfish (Prognichthys occidentalis) larvae in the northern Gulf of Mexico (NGoM). Summer ichthyoplankton cruises were conducted from 2009 to 2011 using a neuston net towed through the upper meter of the water column. Interannual variation was detected with densities of bluntnose flyingfish larvae higher in 2009 and 2010 than 2011. Bluntnose flyingfish larvae were present in each month and year sampled, suggesting that this species is a common and important component of the ichthyoplankton assemblage in this region. Generalized additive models were used to evaluate the effect of oceanographic conditions on the abundance of bluntnose flyingfish, and several environmental variables (sea surface height anomaly, distance to Loop Current, and salinity) were found to be influential in explaining patterns of abundance. Habitat suitability was linked to physicochemical properties of the seawater, and higher larval abundances were found at higher salinities and negative sea surface heights. This study emphasizes the importance of NGoM as a spawning/nursery area of bluntnose flyingfish and suggests that oceanographic conditions play an important role in determining the distribution and abundance of bluntnose flyingfish.
Improvement in the diagnostic evaluation of a positive fecal occult blood test in an integrated health care organization.

Background:Screening for fecal occult blood can be effective in reducing colorectal cancer mortality only if positive tests are appropriately followed up with complete diagnostic evaluation (ie, colonoscopy or flexible sigmoidoscopy with double contrast barium enema) and treatment.Objectives:To exam
On the Use of Quaternions to Characterize the Dynamics of a Vertebral Motion Segment

The characterization of the kinematics and kinetics of anatomical joints is a central problem in biomechanics. Traditionally, the kinematics of the joint has been characterized using the helical axis of motion (HAM) and Euler angles. The estimation of these quantities from optical measurements of landmarks placed on the anatomical parts constituting the joint is difficult and often fraught with error.© 2009 ASME
The Ig Superfamily Cell Adhesion Molecule, apCAM, Mediates Growth Cone Steering by Substrate–Cytoskeletal Coupling

Dynamic cytoskeletal rearrangements are involved in neuronal growth cone motility and guidance. To investigate how cell surface receptors translate guidance cue recognition into these cytoskeletal changes, we developed a novel in vitro assay where beads, coated with antibodies to the immunoglobulin superfamily cell adhesion molecule apCAM or with purified native apCAM, replaced cellular substrates. These beads associated with retrograde F-actin flow, but in contrast to previous studies, were then physically restrained with a microneedle to simulate interactions with noncompliant cellular substrates. After a latency period of ∼10 min, we observed an abrupt increase in bead-restraining tension accompanied by direct extension of the microtubule-rich central domain toward sites of apCAM bead binding. Most importantly, we found that retrograde F-actin flow was attenuated only after restraining tension had increased and only in the bead interaction axis where preferential microtubule extension occurred. These cytoskeletal and structural changes are very similar to those reported for growth cone interactions with physiological targets. Immunolocalization using an antibody against the cytoplasmic domain of apCAM revealed accumulation of the transmembrane isoform of apCAM around bead-binding sites. Our results provide direct evidence for a mechanical continuum from apCAM bead substrates through the peripheral domain to the central cytoplasmic domain. By modulating functional linkage to the underlying actin cytoskeleton, cell surface receptors such as apCAM appear to enable the application of tensioning forces to extracellular substrates, providing a mechanism for transducing retrograde flow into guided growth cone movement.
Family Narratives, Self, and Gender in Early Adolescence:

Past research has suggested that family reminiscing may be a particularly important avenue for the development of children's well-being. In this study, the authors examined the ways in which mothers and fathers scaffold conversations about past emotional events with their preadolescent children. Narratives of positive and negative shared family events were coded for parental expression and explanation of emotion, and these variables were related to measures of children's developing self-esteem and emotional and behavioral adjustment 2 years later. Overall, mothers express and explain more emotion than do fathers, and maternal expression and explanation of emotion within family narratives is generally related to positive self-esteem and adjustment in sons and daughters. However, paternal expression and explanation of emotion within family narratives generally appears to be related to poorer self-esteem and adjustment for sons and daughters. Implications for adolescent development, parental scaffolding of e...
Tonic and Phasic Events during Sleep: Psychological Correlates and Implications:

The most widely accepted model of sleep in recent years has been one which draws qualitative distinctions between stage REM and NREM sleep. This conceptualization is now challenged by a tonic-phasi...
Alzheimer's disease drug development and the problem of the blood-brain barrier

Alzheimer's disease (AD) drug development is limited by the presence of the blood-brain barrier (BBB). More than 98% of all small-molecule drugs, and approximately 100% of all large-molecule drugs, do not cross the BBB. Although the vast majority of AD drug candidates do not cross the BBB, the present-day AD drug-development effort is characterized by an imbalance wherein >99% of the drug-development effort is devoted to central nervous system (CNS) drug discovery, and <1% of drug development is devoted to CNS drug delivery. Future AD drug development needs a concerted effort to incorporate BBB sciences early in the CNS drug discovery process. This goal can be achieved by a reallocation of resources, and an expansion of research efforts in the pure science of BBB biology and the applied science of brain drug-targeting technology.
Gauge Symmetry and Localized Gravity in M Theory

We discuss the possibility of having gravity ``localized'' in dimension d in a system where gauge bosons propagate in dimension d+1. In such a circumstance - depending on the rate of falloff of the field strengths in d dimensions - one might expect the gauge symmetry in d+1 dimensions to behave like a global symmetry in d dimensions, despite the presence of gravity. Naive extrapolation of warped long-wavelength solutions of general relativity coupled to scalars and gauge fields suggests that such an effect might be possible. However, in some basic realizations of such solutions in M theory, we find that this effect does not persist microscopically. It turns over either to screening or the Higgs mechanism at long distances in the d-dimensional description of the system. We briefly discuss the physics of charged objects in this type of system.
Vapor Pressure of 2-(Difluoromethoxy)-1,1,1-trifluoroethane CHF2−O−CH2CF3 (HFE-245)

The vapor pressure of 2-(difluoromethoxy)-1,1,1-trifluoroethane, a candidate alternative refrigerant that is also known as HFE-245, has been measured. The vapor pressure was determined at temperatures between 261 K and 369 K by two ebulliometric techniques. The differences in these two methods arise from the method used to determine pressure. At p < 200 kPa, a comparative instrument was used and pressures were obtained from the temperature at which water boiled at the same pressure. At pressures up to 747 kPa, the pressures were measured directly. A correlation for the vapor pressure from 261 K to the critical temperature is provided. The comparative ebulliometric measurements have an expanded uncertainty (k = 2) of less than 0.0005·p, while the direct ebulliometric measurements have an expanded uncertainty (k = 2) of 0.002·p.
Safety Considerations in the Use of Drug Combinations During General Anaesthesia

The most commonly employed technique for providing general anaesthesia uses a balanced approach, where different drugs are used to reach specific desired endpoints. The variety of drugs used can result in a dozen or more different compounds being administered during a 'routine anaesthetic' procedure. Drug interactions are quite common and their clinical effects can be very significant. Clinically, general anaesthesia has 4 goals. These are: unconsciousness/amnesia; analgesia; muscle relaxation and maintenance of homeostasis. The anaesthesiologist tries to select only those drugs that permit a rapid onset of desirable operative conditions so that surgery can be performed properly and rapidly. Such drugs should also minimally disturb the patient's preoperative homeostatic maintenance, and maximise return to a desirable postanaesthetic functional state.
Probing the Location of the Terminal Groups of Dendrimers in Dilute Solution

The spatial distribution of the terminal groups of poly(amido amine) dendrimers have been determined experimentally by small-angle neutron scattering with deuterium labeling and scattering contrast variation. The radius of gyration of deuterated terminal units of generation 7 dendrimers is 39.3 ± 1.0 A. This is significantly larger than the radius of gyration of the whole dendrimer, which is 34.4 ± 0.2 A. These data indicate that dendrimers have terminal groups that are concentrated near the periphery. These results are inconsistent with many computer simulations and some molecular models.
Issues in clinical ethics consultation: an introduction.

the theme for this current issue. The growth of the Society for Bioethics Consultation - as shown by the increase in attendance at its meetings over the last four years - is indicative of the dramatic growth of interest in clinical ethics and particularly in the area of ethics consultation, whether by an individual or by committee. The first meeting of this organization, held at the National Institutes of Health in 1985, included fifty persons who were invited because they were known either to be actively involved in clinical ethics consultations or because they were considered to be some of the early leaders in the field of bioethics. The 4th annual meeting of the Society for Bioethics Consultation which met in 1990 had 130 paid registrants, most of whom were involved in some way in clinical ethics - particularly ethics consultations or ethics committees. Any area that surges ahead as rapidly as this one has over the last five years is virtually certain to find that there are many problems which will need to be addressed. There will also be a need for persons working in this field (or studying it) to take some time to reflect on where it is going, as well as to examine some of the possible pitfalls - both the obvious and the not so obvious - which lie ahead. The series of papers in this issue of Theoretical Medicine have been written by a group of ethicists who have had a longstanding interest in the field of clinical ethics, and most of whom have spent many years working in the area. While all of the papers focus on the field of clinical ethics, they are very diverse in the topics covered. Some may be viewed as controversial by readers. David Doukas describes a bioethics consultation form he has developed to
False Memory in a Short-Term Memory Task

The Deese/Roediger-McDermott (DRM; Roediger & McDermott, 1995) paradigm reliably elicits false memories for critical nonpresented words in recognition tasks. The present studies used a Sternberg (1966) task with DRM lists to determine whether false memories occur in short-term memory tasks and to assess the contribution of latency data in the measurement of false memories. Subjects studied three, five, or seven items from DRM lists and responded to a single probe (studied or nonstudied). In both experiments, critical lures were falsely recognized more often than nonpresented weak associates. Latency data indicated that correct rejections of critical lures were slower than correct rejections of weakly related items at all set sizes. False alarms to critical lures were slower than hits to list items. Latency data can distinguish veridical and false memories in a short-term memory task. Results are discussed in terms of activation-monitoring models of false memory.
Magnetizing Current, Iron Losses And Forces Of Three-Phase Induction Machines At Sinusoidal And Nonsinusoidal Terminal Voltages. Part I: Analysis

Currents, losses, winding and iron core forces at no-load of saturated three-phase induction machines are determined based on a nonlinear magnetic field analysis. Instantaneous magnetizing currents are calculated for given balanced sinusoidal and nonsinusoidald- terminal voltages. Subsequently, the harmonic components of the magnetizing current and the induced voltage are obtained from a Fourier analysis. The coreloss- current component is derived from the sum of local core losses and the no-load current is then iteratively obtained from the sum of the magnetizing and the coreloss- current components. Finally, the calculation of winding and iron-core forces is derived from surface integrals. Part II deals with the results that are based on this analysis.
Shear deformation in Sn-3.5Ag and Sn-3.6Ag-1.0Cu solder joints subjected to asymmetric four-point bend tests

The shear deformation behavior of two lead-free solder compositions, Sn-3.5Ag (wt.%) and Sn-3.6Ag-1.0Cu (wt.%), both on copper substrates, was studied using an asymmetric four point bend technique. Four test joints were obtained from one master specimen of each composition, and each joint was subject to progressive loading, up to the maximum shear strength of the joint. One unstressed bar from each composition was retained as a reference. Each sample was metallo-graphically plished and lightly etched, and examined in a field emission scanning electron microscope (SEM) before shearing. Sheared joints were then re-examined in the SEM with no additional surface treatment. Compared with the traditional ring and plug method, the asymmetric four-point bend (AFPB) technique subjects the joints to a condition of pure shear, while providing an opportunity for unambiguous observation of microstructural features before and after shearing, without an intervening mechanical sectioning step. Shear banding in the Sn-rich matrix and crack nucleation in the vicinity of the intermetallic interface were observed at low displacements in the binary alloy. Evidence of non-homogeneous plastic flow in the matrix was seen at higher shear loading. No evidence of brittle fracture was observed in the Sn-3.6Ag-1.0 Cu alloy, with elastic deformation at low stress levels giving rise to plastic deformation at higher loading values. Results show that the AFPB technique is a viable approach to the study of shear loading on solder joints.
The Effect of Position and Path Repeatability on Biomechanical Testing of Diarthrodial Joints

To improve surgical procedures and rehabilitation protocols for injuries to the anterior cruciate ligament (ACL), the function of the ACL and ACL graft during in vivo activities must be understood. Robotic manipulators with a payload less than 500 N (low-payload) have been used to study joint and ligament function during application of external loading conditions (Fujie, 1993; Fujie, 2000). Robotic manipulators with a payload capacity of at least 1500 N (high-payload) will be needed to simulate high joint contact forces that have been estimated to be between 2 to 5 times body weight (Morrison, 1970; Escamilla, 1998). However, there is a trade-off between payload capacity and position and path repeatability. The objective of this study was to determine the effect of position and path repeatability of two high-payload robotic manipulators, (KUKA™ KR210 and FANUC™ S900W) used to apply external loads to diarthrodial joints and determine the corresponding joint kinematics and forces in the soft tissue structures.Copyright © 2003 by ASME
AML cytogenetics: the complex just got simpler.

In this issue of Blood , Middeke et al, for the well-regarded Cooperative German Transplant Study Group, report a retrospective analysis in which they demonstrate that a hierarchial classification system for specific cytogenetic abnormalities in acute myeloid leukemia (AML) reveals that patients
Propagation of a Finite Optical Beam in an Inhomogeneous Medium

The first part of this paper is devoted to extending the Huygens-Fresnel principle to a medium that exhibits a spatial (but not temporal) variation in index of refraction. Utilizing a reciprocity theorem for a monochromatic disturbance in a weakly inhomogeneous medium, it is shown that the secondary wavefront will be determined by the envelope of spherical wavelets from the primary wavefront, as in the vacuum problem, but that each wavelet is now determined by the propagation of a spherical wave in the refractive medium. In the second part, the above development is applied to the case in which the index of refraction is a random variable; a further application of the reciprocity theorem results in a formula for the mean intensity distribution from a finite aperture in terms of the complex disturbance in the aperture and the modulation transfer function (MTF) for a spherical wave in the medium. The results are applicable for an arbitrary complex disturbance in the transmitting aperture in both the Fresnel and Fraunhofer regions of the aperture. Using a Kolmogorov spectrum for the index of refraction fluctuations and a second-order expression for the MTF, the formula is used to calculate the mean intensity distribution for a plane wave diffracting from a circular aperture and to give approximate expressions for the beam spreading at various ranges.
Pubertal timing and body mass index gain from birth to maturity in relation with femoral neck BMD and distal tibia microstructure in healthy female subjects

Summary Childhood body mass index (BMI) gain is linked to hip fracture risk in elderly. In healthy girls, menarcheal age is inversely related to BMI gain during childhood and to femoral neck areal bone mass density (aBMD) and distal tibia structural components at maturity. This study underscores the importance of pubertal timing in age-related fragility fracture risk.
Punctuated Evolution Caused by Selection of Rare Beneficial Mutations

For more than two decades there has been intense debate over the hypothesis that most morphological evolution occurs during relatively brief episodes of rapid change that punctuate much longer periods of stasis. A clear and unambiguous case of punctuated evolution is presented for cell size in a population of Escherichia coli evolving for 3000 generations in a constant environment. The punctuation is caused by natural selection as rare, beneficial mutations sweep successively through the population. This experiment shows that the most elementary processes in population genetics can give rise to punctuated evolutionary dynamics.
The effects of excessive occlusal force on the pulp.

Abstract There appears to be an intimate relationship between such disease entities as occlusal trauma and periodontitis and the status of the dental pulp. In an effort to define this relationship more clearly, four studies have been conducted. These deal with the response of the pulp to experimentally induced excessive occlusal force, to orthodontic tooth movement, and to experimentally induced gingivitis and periodontitis.
Who Overvotes, Who Undervotes, Using Punchcards? Evidence from Los Angeles County

In this study we examine over- and undervotes from the November 2000 General Election in Los Angeles County. Los Angeles County is the nation’s largest election jurisdiction, and it used a punchcard voting system in that election. We use precincts as our unit of analysis and merge the 2000 election data with census data and voter registration data; our dataset allows us to examine all of the countywide races in 2000 (including candidate and ballot measures). We use a multivariate statistical analysis employing negative binomial regression to test hypotheses regarding the relationship between precincts’ political and demographic characteristics and over-and undervotes. We demonstrate that both over- and undervotes vary systematically across precincts in Los Angeles County, a finding that we argue has important implications for the representation of political interests.
Intrinsic Point Defects in Silicon Crystal Growth

In dislocation-free silicon, intrinsic point defects – either vacancies or self-interstitials, depending on the growth conditions - are incorporated into a growing crystal. Their incorporated concentration is relatively low (normally, less than 1014 cm-3 - much lower than the concentration of impurities). In spite of this, they play a crucial role in the control of the structural properties of silicon materials. Modern silicon crystals are grown mostly in the vacancy mode and contain many vacancy-based agglomerates. At typical grown-in vacancy concentrations the dominant agglomerates are voids, while at lower vacancy concentrations there are different populations of joint vacancy-oxygen agglomerates (oxide plates). Larger plates – formed in a narrow range of vacancy concentration and accordingly residing in a narrow spatial band – are responsible for the formation of stacking fault rings in oxidized wafers. Using advanced crystal growth techniques, whole crystals can be grown at such low concentrations of vacancies or self-interstitials such that they can be considered as perfect.
Predicting Persistence to Degree of Male College Students

Men are underrepresented within the ivory tower. When the intersection of race and gender is examined, enrollment gaps widen even further. Currently, more opportunities than ever before are available for African Americans and Hispanics to attend college; however, their rates of attaining a bachelor's degree are significantly lower when compared to other ethnic/gender combinations. Select personal characteristics (i.e., race, SES) are known to play a role in men's academic achievement. Beyond those, however, are issues of efficacy. The purpose of this study was to determine what efficacy factors predict persistence to graduation of male students when personal characteristics are controlled for. A modified version of the Bandura et al. (1996) theoretical model was used that identified three factors that influence self-efficacy, hence academic success: familial, peer, and self. The findings suggest that race and select parental and peer factors can have both negative and positive effects on the persistence o...
Fault-tolerant design techniques for semiconductor memory applications

Advances in semiconductor memory technology towards higher-density and higher-performance memory chips have created new reliability challenges for the memory system designer. An example would be the multiple-bit-per-chip organization with the chip outputs used in the same word. This design structure would be prone to uncorrectable errors with conventionally implemented single-error-correcting double-error-detecting codes. With these newer chips, memory system designers will have to give special attention not only to the types of failures but to ways of minimizing the system impact of reliability defects. In this paper, a number of design approaches are presented for minimizing the efects of chip failures through the use of organizational techniques and through enhancements to conventional error checking and correction facilities. The fault-tolerant design techniques described are compatible with most existing memory designs. An evaluative comparison of these techniques is included, and their application and utility are discussed.
Molecular bases for the recognition of tyrosine-based sorting signals.

Targeting of transmembrane proteins to different compartments of the endocytic and late (post-Golgi) secretory pathways is largely dependent upon sorting signals contained within the cytosolic domains of the proteins (reviewed in reference [19][1], [24][2]). The signals are thought to interact with
Guiding School-Choice Reform through Novel Applications of Operations Research

In January 2012, Boston initiated a school-assignment reform. After attending several community meetings, I formulated the reform as an optimization problem of finding school-choice menus and priorities that induce the best combination of equity of access, proximity to home, predictability, and community cohesion. Using previous school-choice data, I fit a discrete choice model of how families select schools, and created a simulation engine that estimated a variety of outcome measures for any plan. I also proposed several new plans, and helped Boston Public Schools analyze a short list of plans in detail. In March 2013, Boston adopted one of these plans, which will affect the 9,500 children who apply to Boston elementary schools each year.
Effects of a ketogenic diet on hippocampal plasticity in freely moving juvenile rats

Ketogenic diets are low-carbohydrate, sufficient protein, high-fat diets with anticonvulsant activity used primarily as a treatment for pediatric epilepsy. The anticonvulsant mechanism is thought to involve elevating inhibition and/or otherwise limiting excitability in the brain. Such a mechanism, however, might also significantly affect normal brain activity and limit synaptic plasticity, effects that would be important to consider in the developing brain. To assess ketogenic diet effects on synaptic transmission and plasticity, electrophysiological recordings were performed at the perforant path/dentate gyrus synapse in awake, freely-behaving juvenile male rats. Electrodes were implanted 1 week prior to recording. Animals were fed regular chow or a ketogenic diet ad libitum for 3 weeks before recording. Although the ketogenic diet did not significantly alter baseline excitability (assessed by input–output curves) or short-term plasticity (using the paired-pulse ratio), it did reduce the magnitude of long-term potentiation at all poststimulation timepoints out to the last time measured (48 h). The results suggest an effect of ketogenic diet-feeding on the induction magnitude but not the maintenance of long-term potentiation. The lack of effect of the diet on baseline transmission and the paired-pulse ratio suggests a mechanism that limits excitation preferentially in conditions of strong stimulation, consonant with clinical reports in which the ketogenic diet alleviates seizures without a major impact on normal brain activity. Limiting plasticity in a seizure-susceptible network may limit seizure-induced epileptogenesis which may subserve the ongoing benefit of the ketogenic diet in epilepsy.
Voltage Sags and the Response of a Synchronous Distributed Generator: A Case Study

The dynamic behavior of a synchronous distributed generator connected to a distribution system during fault conditions is studied. A fault on an actual system was found to have a sag that was extended after the fault was cleared. It is shown that the combination of the generator and the load on the system contributes to the extended sag. The detailed simulation studies demonstrate that the primary factors are the reactive power drawn by the load during the fault and recovery along with the reaction of the generator. The prediction of such behavior requires proper modeling of the generator, the generator's controls, and the system and dynamic load. Operators of such generators need to be aware of this type of system and load response when synchronous DG is connected to a distribution network.
Food Preferences of Kinkajous (Potos flaws): A Frugivorous Carnivore

The diet of the kinkajou ( Potos flavus ) is described from analyses of feces and observations of habituated individuals. Ripe fruit was the primary food comprising 90.6% of feeding bouts and present in 99% of feces. Leaves and flowers made up <10% of the diet. No animal prey was eaten. Seventy-eight species of fruit from 29 families were detected. Moraceae was the main plant family in the diet and Ficus was the most important plant genus. Kinkajous preferentially fed in large fruit patches. Selection indices were calculated for 37 fruit species. Compared with other large mammalian frugivores in central Panama the diet of kinkajous is most similar to the spider monkey ( Ateles geoffroyi ).
Passive ranging in outdoor environment

The general outdoors passive ranging scenario is one of the most challenging and important areas of research for an optical sensor system moving free in the three dimensional space. We describe here an integrated system of image processing and AI algorithms developed and demonstrated at the Systems and Research Center of Honeywell. This passive ranging system produces a dense range map of an outdoors scene, based only on the sensed imagery and the average speed of the aircraft. No additional knowledge is required about the terrain or the aircraft/sensor attitude changes.
A piezoelectric-sound-resonance cavity for hydrogen gas detection

A new concept for hydrogen gas (H/sub 2/) detection has been developed. This concept is based on a piezoelectric-sound-resonance cavity (PSRC). Detection uses sound resonance and the acoustic property differences of gases as a sensing mechanism in which there is a significant difference in the sound velocity and acoustic impedance between H/sub 2/ and air. The PSRC sensor consists of two thin piezoelectric discs, separated by a small cavity. One disc excites a weak acoustic standing wave in the cavity, and the second senses the wave by monitoring the acoustic impedance characteristics of the cavity. Changes in H/sub 2/ concentration result in a shift of the sound resonance state. Investigations of a PSRC prototype have demonstrated a sensitivity limit of <10 ppm, a fast response time /spl sim/1 second, and a signal (phase and voltage) in proportion to the change in H/sub 2/ concentration (n) over the range of 10/sup -5/ < n < 0.2. These performance characteristics are far superior to those of other methods.
Contributions of 20-HETE to the Antihypertensive Effects of Tempol in Dahl Salt-Sensitive Rats

The present study evaluated whether reactive oxygen species-induced alterations in bioavailability of 20-HETE in the kidney contribute to the antihypertensive and renoprotective actions of antioxidant therapy with Tempol in the Dahl salt-sensitive (DS) rat. Superoxide inhibited the synthesis of 20-HETE by renal cortical microsomes and enhanced breakdown of 20-HETE to a more polar product. Addition of Tempol (1 mmol/L) to the drinking water reduced mean arterial pressure from 187+/-9 to 160+/-3 mm Hg in DS rats fed an 8%-NaCl diet for 2 weeks. 20-HETE excretion rose from 117+/-11 to 430+/-45 ng/day, and 8-isoprostane excretion fell from 14+/-1 to 8+/-1 ng/day. Tempol also increased creatinine clearance and reduced the severity of renal damage in DS rats fed a high-salt diet. Blockade of NO synthase with NG-nitro-L-arginine methyl ester (25 mg/kg per day) did not attenuate the antihypertensive or renoprotective actions of Tempol in DS rats. However, chronic blockade of the formation of 20-HETE with N-hydroxy-N'-(4-butyl-2 methylphenyl) formamidine (HET0016, 10 mg/kg per day) blunted the antihypertensive and renoprotective effects of Tempol. These findings indicate that the antihypertensive and renoprotective effects of reducing oxidative stress with Tempol depends in part on increasing the bioavailability of 20-HETE in the kidney.
Improving learning and engagement for students in large classes

Due to increasing student enrollments and limited resources, small classes are evermore being replaced with large lectures. It is therefore essential to quality educational programs to address the challenges of student learning and engagement in large classes. This paper explains connections between basic learning research and practical strategies for engaging students in large engineering classrooms. First, we ground proposed instructional strategies with theory and empirical evidence on such key matters as how students represent ideas in memory, how these representations are elaborated and perfected over time, and how stored information can be retrieved for use. This helps us to understand how students learn to monitor and control their own learning and how large class environments can be approached as sites for significant learning. We discuss how electronic student response devices (clickers) have been useful for generating in-class interaction and active learning in large classes for individual and team activities. How to administer beneficial team-based projects for large classes is also presented, including: real-world problems that require teams to investigate and understand contemporary issues such as sustainability, working with industry, and third- world countries. Finally, personal style and characteristics of faculty who are successful with large classes is discussed.
New methods in epidemiology.

The pioneers in epidemiology were justifiably called “shoe leather” epidemiologists for their strong field work and willingness to hike into the Netherlands in search of answers to epidemics. I recall a beloved teacher, Dr. George Comstock, with his ingenious knitting needle that sorted data cards and enabled him to analyze data while up in Alaska or investigating a TB outbreak. Early textbooks in epidemiologic methods ventured with an element of distrust towards multi-variable models, cautioning (and wisely) that they were a black box and ill used by the uninformed. As students, we learned to investigate infectious disease outbreaks in our beginning epidemiology classes, and the simple cross tabulations and chi square analyses were sufficient to incriminate the guilty food, and lead to remedial actions. At Johns Hopkins, no one ate egg salad sandwiches for years after that class. Epidemiology has grown more complex today, and while the backbone of the discipline is still population based approaches to understanding diseases, the multi-factorial nature of health problems, tools at our disposal, and the growth in sophisticated biostatical methods have altered the analytic armamentarium at our disposal. This is especially true in Ophthalmology, where issues of clustering were faced decades ago with the need to accommodate the information from both eyes in a single head. In an effort to keep our readership informed about some of the latest methods in use, we are inaugurating a “Methods Series” this year, written by some of the most talented methodologists in the field. Dr. Robert Massof leads off this series with an article on item response theory models. For investigators who use questionnaires to garner data on outcomes such as functional impairment or quality of life, or physical disability, this article is especially important for understanding the creation of rating scales. Any new instrument devised to measure, for example, “Quality of Life in Patients with Z syndrome” should be subjected to more rigorous testing of score creation than simply summing up responses. Rasch models are one approach to this issue, but not the only one. In forthcoming issues, we will have articles on Structural Equation Modeling, Competing Risk models, and approaches to multi-level clustering of data. Applications to research in Ophthalmology will be stressed, and our hope is the articles will prove helpful to investigators faced with complex analytic problems. Furthermore, if readers also identify another methodological area that needs description and demonstration of applicability, we at Ophthalmic Epidemiology would be most responsive to such a submission. Reviewers are increasingly more sophisticated about appropriate methods for data analyses of complex problems, and those of us who wear our “shoe leather” proudly would be well advised to also advance our understanding of these new approaches. By the way, I still do not eat egg salad
TOP-DOWN VERSUS BOTTOM-UP ANALYSES OF INTERLANGUAGE DATA

We are grateful to Hidetoshi Saito for his careful and reasoned critique of the VARBRUL procedure in his article, “Dependence and Interaction in Frequency Data Analysis in SLA Research” (this issue). Saito reanalyzes Young's (1988, 1991) study of -s plural variation in the English interlanguage of native speakers of Chinese. He raises two criticisms of the statistical analyses in the original work: (a) data from all participants were lumped together, resulting in an analysis that ignores possible variation across participants; and (b) interaction between independent variables was not investigated, whereas Saito finds that an interaction term contributes to a statistical model that fits the data better than the original analysis.
A scalable Role-based Group Key Agreement and Role Identification mechanism

Large-scale organizations often use role-based hierarchical systems for managing human resources. Meanwhile, secure communication is an essential element in protecting an organization's intellectual property. In this paper, we propose a solution to the problem of securing group communication (i.e. multiple-peer communication) along with the difficulty of managing such communication system in a large-scale and role-based environment. A role-based conference key generation algorithm is proposed to produce chained-keys by recursive hashing. The proposed work makes it possible that a user with a higher clearance can audit the communications among the users that are hierarchically below him/her. Furthermore, the compartmentalization problem in the previous version is solved by introducing Role Identification Certificates (RICs) using the same key-chain algorithm, so that communications within a group will not be exposed to the outsiders. A centralized key management server is used to securely dispatch the keys to each communicating entity based on his/her role. This lowers the cost associated with deployment of a good Random Number Generator (RNG) and reduces the packet size compared to traditional PKI systems.
Idempotent code generation: Implementation, analysis, and evaluation

Leveraging idempotence for efficient recovery is of emerging interest in compiler design. In particular, identifying semantically idempotent code and then compiling such code to preserve the semantic idempotence property enables recovery with substantially lower overheads than competing software techniques. However, the efficacy of this technique depends on application-, architecture-, and compiler-specific factors that are not well understood. In this paper, we develop algorithms for the code generation of idempotent code regions and evaluate these algorithms considering how they are impacted by these factors. Without optimizing for these factors, we find that typical performance overheads fall in the range of roughly 10-15%. However, manipulating application idempotent region size typically improves the run-time performance of compiled code by 2-10%, differences in the architecture instruction set affect performance by up to 15%, and knowing in the compiler whether control flow side-effects can or cannot occur can impact performance by up to 10%. Overall, we find that, with small idempotent region and careful architecture- and application-specific tuning, it is possible to bring compiler performance overheads consistently down into the single-digit percentage range. The absolute best performance occurs when constructing the largest possible idempotent regions; to this end, however, better compiler support is needed. In the interest of spurring development in this area, we open-source our LLVM compiler implementation and make it available as a research tool.
Responses of foliar gas exchange to long-term elevated CO2 concentrations in mature loblolly pine trees

Branches of field-grown mature loblolly pine (Pinus taeda L.) trees were exposed for 2 years (1992 and 1993) to ambient or elevated CO(2) concentrations (ambient + 165 micro mol mol(-1) or ambient + 330 micro mol mol(-1) CO(2)). Exposure to elevated CO(2) concentrations enhanced rates of net photosynthesis (P(n)) by 53-111% compared to P(n) of foliage exposed to ambient CO(2). At the same CO(2) measurement concentration, the ratio of intercellular to atmospheric CO(2) concentration (C(i)/C(a)) and stomatal conductance to water vapor did not differ among foliage grown in an ambient or enriched CO(2) concentration. Analysis of the relationship between P(n) and C(i) indicated no significant change in carboxylation efficiency of ribulose-1,5-bisphosphate carboxylase/oxygenase during growth in elevated CO(2) concentrations. Based on estimates derived from P(n)/C(i) curves, there were no apparent treatment differences in dark respiration, CO(2) compensation point or P(n) at the mean C(i). In 1992, foliage in the three CO(2) treatments yielded similar estimates of CO(2)-saturated P(n) (P(max)), whereas in 1993, estimates of P(max) were higher for branches grown in elevated CO(2) than in ambient CO(2). We conclude that field-grown loblolly pine trees do not exhibit downward acclimation of leaf-level photosynthesis in their long-term response to elevated CO(2) concentrations.
Hyaluronate and Hyaluronidase in Morphogenesis and Differentiation

Hyaluronate turnover is correlated with morphogenetic events during chondrogenesis in the regenerating newt limb and in the chick embryo limb and axial preskeleton and during development of the chick embryo cornea. In vitro hyaluronate, in concentrations as low as 1 ng/ml, blocks the formation of cartilage—like aggregates in high density stationary cultures of stage 26 chick embryo somite cells. This inhibition is prevented by hormones known to promote skeletal development and by adenosine 3',5'cyclic monophosphate. An hypothesis is discussed in which (1) hyaluronate may interfere with cell interactions leading to aggregation, encapsulation by matrix and consequent immobilization and (2) hyaluronate turnover could provide a means of timing of morphogenetic events such as cell migrations, allowing sufficient accumulation of cells prior to overt differentiated tissue formation.
Ubiquity and Specificity of Reinforcement Signals throughout the Human Brain

Reinforcements and punishments facilitate adaptive behavior in diverse domains ranging from perception to social interactions. A conventional approach to understanding the corresponding neural substrates focuses on the basal ganglia and its dopaminergic projections. Here, we show that reinforcement and punishment signals are surprisingly ubiquitous in the gray matter of nearly every subdivision of the human brain. Humans played either matching-pennies or rock-paper-scissors games against computerized opponents while being scanned using fMRI. Multivoxel pattern analysis was used to decode previous choices and their outcomes, and to predict upcoming choices. Whereas choices were decodable from a confined set of brain structures, their outcomes were decodable from nearly all cortical and subcortical structures. In addition, signals related to both reinforcements and punishments were recovered reliably in many areas and displayed patterns not consistent with salience-based explanations. Thus, reinforcement and punishment might play global modulatory roles in the entire brain.
Effect of rabbit antisecretin serum on postprandial pancreatic secretion in dogs.

Abstract To determine the contribution made by endogenous secretin to pancreatic bicarbonate secretion in the postprandial state, normal rabbit serum or rabbit antisecretin serum was administered intravenously to dogs with a pancreatic fistula and gastric cannula. In the four dogs tested, plasma immunoreactive secretin concentration increased significantly after ingestion of a standard meal containing meat. In nine dogs, the administration of rabbit antisecretin serum resulted in a profound decrease in pancreatic flow and the concentration and output of pancreatic bicarbonate after the meal. The total bicarbonate output decreased to