cssi/SciSciGPT-SciSciNet huggingface dataset:
QT interval dynamics and triggers for QT prolongation immediately following cardiac arrest.

Abstract Background The prolongation in QT interval typically observed following cardiac arrest is considered to be multifactorial and induced by external triggers such as hypothermia therapy and exposure to antiarrhythmic medications. Objective To evaluate the corrected QT interval (QTc) dynamics in the first 10 days following cardiac arrest with respect to the etiology of arrest, hypothermia and QT prolonging medications. Methods We enrolled 104 adult survivors of cardiac arrest, where daily ECG was available for at least 3 days. We followed their QT and QRS intervals for the first 10 days of hospitalization. We used both Bazett and Fridericia formulas to correct for heart rate. For patients with QRS 120 ms we analyzed the JTc (n = 104) vs. including only the narrow QRS samples (n = 89). We stratified patients by 3 groups: (1) presence of ischemic heart disease (IHD) (2) treatment with hypothermia protocol, and (3) treatment with QTc prolonging medications. Additionally, genetic information obtained during hospitalization was analyzed. Results QTc and JTc intervals were significantly prolonged in the first 6 days. Maximal QTc/JTc prolongation was observed in day 2 (QTcB = 497 ± 55). There were no differences in daily QTc/JTc and QRS intervals in the first 2 days post arrest between patients with or without hypothermia induction but such difference was found with QT prolonging medications. All subgroups demonstrated significantly prolonged QTc/JTc interval regardless of the presence of IHD, hypothermia protocol or QTc prolonging medication exposure. Our results were consistent for both Bazetts’ and Frediricia correction and for any QRS duration. Prolongation of the JTcB beyond 382 ms after day 3 predicted sustained QTc/JTc prolongation beyond day 6 with an ROC of 0.78. Conclusions QTc/JTc interval is significantly and independently prolonged post SCA, regardless of known QT prolonging triggers. Normalization of the QTc post cardiac arrest should be expected only after day 6 of hospitalization. Assessment of the QTc for adjudication of the etiology of arrest or for monitoring the effect of QT prolonging medications may be unreliable.
Optimal immune specificity at the intersection of host life history and parasite epidemiology

Abstract Epidemiology and life history are commonly hypothesized to influence host immune strategy, and the pairwise relationships between immune strategy and each factor have been extensively investigated. But the interaction of these two is rarely considered, despite evidence that this interaction might produce emergent effects on optimal immune strategy. Here we investigate the confluence of epidemiology and life history as it affects immune strategy through a demographically-framed model of sensitivity and specificity in parasite recognition and response. We find that variation in several different life history traits associated with both reproduction and longevity alters optimal immune strategies – but the direction and magnitude of these effects depends on how epidemiological risks vary across life. Drawing on published life history data, we also find that our predictions apply across chordate taxa. Our results shed light on the complex interactions shaping immune strategy and may prove valuable in interpreting empirical results in ecoimmunology.
Approximating the (Continuous) Fréchet Distance

We describe the first strongly subquadratic time algorithm with subexponential approximation ratio for approximately computing the Frechet distance between two polygonal chains. Specifically, let P and Q be two polygonal chains with n vertices in d-dimensional Euclidean space, and let α ∈ [√n, n]. Our algorithm deterministically finds an O(α)-approximate Frechet correspondence in time O((n³ / α²) log n). In particular, we get an O(n)-approximation in near-linear O(n log n) time, a vast improvement over the previously best know result, a linear time 2^O(n)-approximation. As part of our algorithm, we also describe how to turn any approximate decision procedure for the Frechet distance into an approximate optimization algorithm whose approximation ratio is the same up to arbitrarily small constant factors. The transformation into an approximate optimization algorithm increases the running time of the decision procedure by only an O(log n) factor.
The role of tax-filing status in uncovering socioeconomic and physical activity differences in college-aged students.

OBJECTIVE This study examined relationships among multifaceted measures of socioeconomic status (SES) and physical activity (PA) in undergraduates. Participants were classified into dependent and independent tax filers to encapsulate the atypical divide in financial responsibility. Participants: 366 diverse American undergraduates. Methods: Participants completed an online survey including three SES metrics and the International Physical Activity Questionnaire. Results: Participants engaged in the same amount of total PA, albeit different proportions depending on SES measure and PA type. Independent tax filers engaged in more occupational PA than dependent tax filers, regardless of SES. Students with low SES engaged in less leisure-time PA than students with high SES. Conclusion: Household Material Hardship and SES proxy measures should be considered in the context of tax filing status among undergraduates. Greater precision with multifactorial SES measures will assist in providing the nuanced context when optimizing interventions and reducing barriers to increase PA in young adults.
An Empirical Examination of Voluntary Development Activities of Employees

This study develops and empirically examines a model of voluntary employee self-development behaviours and presents a unique lens for the study of self-development behaviours that integrates the di...
Neutron star structure with a new force between quarks

The discovery of nondiffuse sources of gravitational waves through compact-object mergers opens new prospects for the study of physics beyond the Standard Model. In this paper, we study the effects of a new force between quarks, suggested by the gauging of baryon number, on pure neutron matter at supranuclear densities. This leads to a stiffening of the equation of state, allowing neutron stars to be both larger and heavier and possibly accommodating the light progenitor of GW190814 as a neutron star. The role of conventional three-body forces in neutron star structure is still poorly understood, though they can act in a similar way, implying that the mass and radius do not in themselves resolve whether new physics is coming into play. However, a crucial feature of the scenario we propose is that the regions of the new physics parameter space that induce observable changes to neutron star structure are testable at low-energy accelerator facilities. This testability distinguishes our scenario from other classes of new phenomena in dense matter.
Structural and Biochemical Changes in Aging Skin and Their Impact on Skin Permeability Barrier

Publisher Summary Skin transformations are the most perceptible signs of aging. The multifaceted functions of the skin include acting as an entry barrier to compounds, regulating body temperature and fluid and electrolyte balance, and providing receptors for sensations such as touch, pain, and pressure. This chapter presents a synopsis of systematic and detailed studies on this topic. As skin ages, it undergoes certain morphological and functional changes, which lead to altered drug permeability, increased susceptibility to irritant contact dermatitis, and in addition possibly severe xerosis. From the published literature, it seems that the thickness of the stratum corneum does not change significantly with age, but there is an increase in the surface area of the corneocytes. Other major changes include reduced elasticity of the epidermis, a decrease in the number of sweat glands and an increased loss of collagen and elastin. There are a number of smaller variations occurring structurally and biochemically with age such as the reduction in skin lipids and a reduction in cell turnover. The complex nature and high number of changes occurring simultaneously as well as the experimentally introduced variations due to the use of subjects of different races, genders, ethnicity, and ages make it difficult to draw conclusive correlations between such changes and alterations in permeation of drugs through aged skin.
The role of phosphorylation and limited proteolytic cleavage of talin and vinculin in the disruption of focal adhesion integrity

Chemical agents which activate specific kinases were employed to disrupt the stress fiber and focal adhesion organization of cells spread on a substratum. The phorbol ester 12-O-tetradecanoylphorbol-13-acetate, an activator of protein kinase C, promoted a rapid loss of stress fibers and focal adhesions from African green monkey kidney (BSC-1) cells. This was paralleled by an increase in the level of talin phosphorylation suggesting that this may play a role in the removal of talin from focal adhesions. Similar morphological changes were produced in the rat embryo fibroblast line (REF 52) by dibutyryl-cAMP, which stimulates protein kinase A. In contrast, however, the phosphorylation of talin was reduced in REF 52 cells when treated with dibutyryl cAMP. In untreated cells we found that the levels of vinculin phosphorylation were very low relative to the levels of talin phosphorylation and did not change following drug treatment in either cell line. Although limited proteolytic cleavage of cytoskeletal proteins represents a potential mechanism for focal adhesion disruption, we observed no proteolysis of talin or vinculin in response to either drug treatment.
Comparison of symbolic analysis, approximation and macromodeling techniques for statistical design for quality of analog integrated circuits

A comparison of symbolic analysis, approximation and macromodeling techniques for statistical circuit design is presented in this paper. The applicability of these techniques for statistical design of analog integrated circuits is stressed through practical examples. Difficulties and open problems are also discussed with emphasis on statistical circuit design.
BEST Practices for Broadening Participation in the Geosciences: Strategies from the UCAR Significant Opportunities in Atmospheric Research and Science (SOARS®) Program

This article offers a set of design principles distilled from the Building Engineering and Science Talent (BEST) examination of over 100 programs with documented success in recruiting and retaining minority students in sciences, technology, engineering and mathematics. By illustrating these principles in the context of the Significant Opportunities in Atmospheric Research and Science (SOARS®) program, we provide examples for applying them in the realm of the geosciences. The SOARS Program combines multiple summer research experiences with intensive, multidimensional mentoring and a robust learning community to help undergraduate students complete college and make successful transitions into graduate school in the Atmospheric and related sciences. SOARS has been widely recognized through formal and informal assessments as a highly successful program.
Western European trade as a measure of integration: untangling the interpretations:

Past utilization of foreign trade data as an indicator of integrative behavior and tendencies in Western Europe and especially in the Common Market provides a good illustration of a situation in which different analysts use the same data to support contradictory conclusions. This fact argues for a closer look at both the methodology and the interpretation of such data. On a technical plane the fact that substantial interpretative differences can result simply from statistical technique should caution the analyst to ensure that his statistical manipulations are the ones most appropriate for showing the effects in which he is interested. More
The Tulsa race war of 1921

S ixty-four people were lynched in the United States in 1921-59 of them were Negroes. During the previous two decades, more than three thousand people had been lynched in the United States (New York Times, 192 la). Lynching was not an unusual phenomenon in Oklahoma, and if the victim were black there was no censure. Oklahoma's most erudite periodical, Harlow 's Weekly (1 921 a) editorialized succinctly:
Morphological diversification of Paleozoic crinoids

Several metrics, including average difference among species, range of occupied morpho- logical space, and number of character-state combinations, are used to investigate morphological diversification in Paleozoic crinoids. Despite several phases of taxonomic diversification, the max- imal level of disparity reached in the Ordovician remained essentially unsurpassed. Although new regions in morphological space were occupied after the Devonian, these were not as extensive as those that had been evacuated prior to the Carboniferous. This discordance between extensive total morphological change and limited net change further supports previous arguments for the impor- tance of morphological constraints in crinoid evolution. Major changes in the occupation of mor- phological space correspond with changes in taxonomic diversity within certain higher taxa. The extent to which advanced cladids (Poteriocrinina) appear to expand into new morphological space is exaggerated by the large number of very similar species in this group. If fewer species are sampled, by considering only those forms that differ from each other by at least some prescribed amount, poteriocrines appear to be less extreme morphologically. In contrast, other groups that seem to occupy unique regions in morphological space continue to do so even if fewer of them are sampled. Major crinoid clades-Camerata and Cladida+Flexibilia-do not show the same evolutionary pat- tern as Crinoidea, but instead exhibit a more gradual diversification of morphology. This observation provides additional support for the existence of qualitative differences among taxa of different rank.
Heparin inhibits EcoRI endonuclease cleavage of DNA at certain EcoRI sites.

Abstract Studies presented here demonstrate that heparin inhibits EcoRI endonuclease cleavage of DNA whereas related proteoglycans show no effect. The inhibition occurs at particular EcoRI sites that are near or overlap with palindromic sequences in the murine lambda 5 and Lyt-2 genes. Endogenous heparin from peritoneal mast cells co-isolates with DNA and inhibits digestion of peritoneal cell DNA at the inhibitable sites. Digestion of spleen DNA is inhibited at the same sites when commercial heparin is added prior to digestion. In both cases, the inhibition is abolished by pre-treating the DNA with heparinase. Thus, potential artifacts in restriction fragment length analyses could occur with DNA isolated either from cells that are naturally rich in heparin or from cells to which heparin has been added, e.g., as an anticoagulant.
Nonimaging optics in luminescent solar concentration

Light trapped within luminescent solar concentrators (LSCs) is naturally limited in angular extent by the total internal reflection critical angle, θcrit, and hence the principles of nonimaging optics can be leveraged to increase LSC concentration ratio by appropriately reshaping the edges. Here, we use rigorous ray-tracing simulations to explore the potential of this concept for realistic LSCs with compound parabolic concentrator (CPC)-tapered edges and show that, when applied to a single edge, the concentration ratio is increased by 23% while maintaining >90% of the original LSC optical efficiency. Importantly, we find that CPC-tapering all of the edges enables a significantly greater intensity enhancement up to 35% at >90% of the original optical efficiency, effectively enabling two-dimensional concentration through a cooperative, ray-recycling effect in which rays rejected by one CPC are accepted by another. These results open up a significant opportunity to improve LSC performance at virtually no added manufacturing cost by incorporating nonimaging optics into their design.
Posttensioned Energy Dissipating Connections for Moment-Resisting Steel Frames

The seismic performance of a posttensioned energy dissipating (PTED) connection for steel frames is investigated analytically and experimentally. The PTED connection incorporates posttensioned high-strength bars to provide a self-centering response along with energy dissipating bars that are able to yield in axial tension and compression. The analytical study involves the development of an equivalent iterative sectional analysis procedure to predict the moment-rotation relationship of the PTED connection. Based on this analytical model, a simple design procedure for PTED connections is described. In the experimental study, a cyclic component test was performed on two energy dissipating bars and a cyclic test was conducted on a large-scale exterior beam-to-column PTED connection. The results of the tests show that the PTED test specimen was able to undergo large inelastic deformations without any damage in the beam or column and without residual drift. The proposed analytical model and design procedure wer...
ECONOMY AND SCHEMES OF RECURRENCE: SUSTAINABILITY AS AN ECONOMIC AND ETHICAL VALUE

Sustainability has become an important catch‐word in several fields that has stimulated an important body of work on a wide variety of topics ranging from economic development and agricultural production to social equity and biodiversity. Few generalizations can be made about such a diverse body of work. However, one can say with some confidence that this reflection has come about in large part from a sense that certain activities constitute a threat to human well‐being through the destruction of the necessary conditions of human survival. This fact has contributed to a rampant pessimism regarding prospects for the future and a rethinking of the meaning of sustainability in the fields noted above. However, acknowledging that sustainability is a rich concept in current thinking about economy, environment, and ecology does not mean that it is clearly understood. Indeed, the opposite is true. For example, John Pezzey, in a recent World Bank study, identified twenty‐seven definitions of sustainability. Even a summary survey of the work about sustainability shows that the term is a multidimensional concept that comprises of a number of interrelated elements, including ecological, environmental, economic, technological, social, cultural, ethical, and political dimensions.
Return eye movements, an ocular compensatory reflex in the alert cat and monkey.

Abstract Eye movements induced by ampullary nerve stimulation in the alert cat and monkey are biphasic in nature. The eyes initially deviate from their original position in the orbit in directions detailed in previous studies. The initial deviations are generally interrupted or followed by active movements in the opposite direction. These opposing movements are the subject of this report. They have been designated “return eye movements” since they tend to return the eyes toward or past their initial position in the orbit. They are a central oculomotor reflex. This reflex serves to maintain the visual angle in space by opposing sudden unexpected shifts of the retina and projected visual field. It also appears to coordinate compensatory head and eye movements during impulses of angular acceleration. The ease of eliciting this ocular reflex in the cat and monkey suggests that it plays an important role in ocular compensation in these animals and probably in man as well.
Validation and quantification of an in vitro model of continuous infusion of submicron-sized particles.

Wear particles produced from total joint replacements have been shown to stimulate a foreign body and chronic inflammatory reaction that results in periprosthetic osteolysis. Most animal models that simulate these events have used a single injection of particles, which is not representative of the clinical scenario, in which particles are continuously generated. The goal of this study was to evaluate the feasibility of an osmotic pump for the continuous delivery of clinically relevant submicron-sized particles over an extended period of time. Blue-dyed polystyrene particles and retrieved ultra-high molecular weight polyethylene (UHMWPE) particles, both suspended in mouse serum, were loaded into an Alzet mini-osmotic pump. Pumps were attached to vinyl tubing that ended with hollow titanium rods, simulating a metal implant, which was suspended in a collection vessel. The number of particles collected was evaluated over 2- and 4-week time periods. Delivery of both the polystyrene and UHMWPE particles was feasible over pump concentrations of 109 to 1011 particles per pump. Furthermore, delivery efficiency of polystyrene particles decreased with increasing initial particle concentration, whereas delivery efficiency of UHMWPE particles increased slightly with increasing initial particle concentration. For UHMWPE, approximately one-third of the particles in the pump were collected at 4 weeks. This in vitro study has quantified the efficiency of a unique particle pumping system that may be used in future in vivo investigations to develop a murine model of continuous particle infusion. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
The law of large numbers with a continuum of IID random variables

Abstract There are two problems with the common argument that a continuum of independent and identically distributed random variables sum to a nonrandom quantity in “large economies”. First, it may be unintelligible in that it may call for the measure of a nonmeasurable set. However, there is a probability measure, consistent with the finite-dimensional distributions, which assigns zero measure to the set of realizations having that difficulty. A second difficulty is that the “law of large numbers” may not hold even when there is no measurability problem.
Electroluminescence in GaN

Light-emitting diodes of GaN have been made, which can generate CW light over any portion of the visible spectrum and in the near ultraviolet. External power efficiencies of the order of 10−4 can be obtained at room temperature. Annealing treatments of Zn-doped insulating GaN greatly increase the emission efficiency.
Multisensor Process Performance Assessment Through Use of Autoregressive Modeling and Feature Maps

This paper presents an algorithm for quantitative assessment of process or machine performance. The algorithm is based on the fusion of multiple sensor inputs and matching of the currently observed system signatures against those observed during its normal behavior. In contrast to traditional monitoring techniques, neither faulty data nor historical data are needed for the performance assessment to be made. This quantitative information about process performance can be used to take appropriate maintenance action in a timely manner. Effectiveness of the methods presented in this paper was experimentally demonstrated in multisensor welding process assessment.
The role of p38 in UVA-induced cyclooxygenase-2 expression in the human keratinocyte cell line, HaCaT.

We examined the expression of cycloxygenase-2, the rate-limiting enzyme in the production of prostaglandins, in the UVA-irradiated human keratinocyte cell line, HaCaT. UVA induced a dose-dependent increase in COX-2 at the protein level at 2 and 4 h post-irradiation and at the mRNA level at 1 and 2 h post-irradiation. Experiments using semi-quantitative RT–PCR demonstrate that UVA increased the half-life of the COX-2 message by more than fourfold in the presence of Actinomycin D (with a half life between 4 and 8 h post-irradiation), suggesting that UVA induction of COX-2 is post-transcriptionally regulated. Through the use of the specific p38 inhibitor, SB202190, increases in COX-2 message and protein levels were abrogated in UVA-irradiated cells. In UVA-irradiated cells treated with SB202190, the half-life of the COX-2 message was decreased to basal levels (between 1 and 2 h post-irradiation), indicating that p38 was responsible for the stabilization of the message. Luciferase activity was increased in UVA-irradiated cells transfected with reporter constructs containing the 3′ UTR of COX-2, a region containing AU-rich elements (AREs). These regulatory sequences of AUUUA have been proposed as one mechanism of post-transcriptional regulation. Increases observed in luciferase activity could be decreased using a p38 dominant-negative construct. We report for the first that UVA can induce COX-2 expression in the human keratinocyte cell line, HaCaT. Additionally, p38 appears to play a critical role in the UVA-induced expression of COX-2 in these keratinocytes and may serve as a potential drug target in the chemoprevention of skin cancer.
A cognitive and behavioral hierarchical decision‐making model of college students' alcohol consumption

This study examined college students' drinking behaviors from a consumer behavioral perspective. A consumer-oriented, cognitive, and behavioral-hierarchical decision-making model was developed and tested with the use of structural equation modeling. Questionnaires were collected from undergraduate students ( n = 269) attending a large state university in the southwestern United States. Results indicated that personal values can serve as significant predictors of the attitudes college students have toward alcohol use, which in turn can predict intentions to drink. Results also indicated that intentions to drink are strongly related to actual alcohol consumption, and that gender-predicted attitudes and alcohol use during the past month influences intentions to drink. However, the structure of the model was similar after controlling for gender differences in alcohol use and for the stability of past behavior. The model delineated the specific roles played by personal values (self-actualizing values vs. social–hedonic values) and attitudes toward the physical and psychological consequences of drinking. Overall, social–hedonic values and psychological consequences predicted actual alcohol consumption far better than did self-actualizing values and physical consequences, respectively. Theoretical and practical implications are discussed, and directions for future research are suggested. © 2005 Wiley Periodicals, Inc.
Fractal art using variations on escape time algorithms in the complex plane

The creation of fractal art is easily accomplished through the use of widely-available software, and little mathematical knowledge is required for its use. But such an approach is inherently limiti...
Regulation of Thymidylate Synthase Gene Expression in Mouse Fibroblasts Synchronized by Mitotic Selection

Abstract Previous studies have shown that thymidylate synthase gene expression is regulated over a wide range in response to growth stimulation in cultured mouse fibroblasts. In the present study we show that the gene is also regulated during the cell cycle in continuously growing cells. Our analyses were conducted with a fluorodeoxyuridine-resistant mouse 3T6 cell line that overproduces thymidylate synthase and its mRNA by a factor of 50 due to gene amplification. Cells were synchronized by mitotic selection. RNA blot analyses showed that the amount of thymidylate synthase mRNA increased 5- to 10-fold as cells progressed from G1 through the middle of S phase. S1 nuclease protection assays showed that the pattern of 5′ termini of thymidylate synthase mRNA was the same in G1 and S phase. Despite the large increase in thymidylate synthase mRNA content, the level of the enzyme increased only by a factor of 2 as cells progressed from G1 to mid S phase. This apparent discrepancy can be explained by the fact that the enzyme is highly stable.
Direct and iterative algorithms for the three-dimensional Euler equations

Direct and iterative algorithms have been developed for solving a finite volume discretization of the three-dimensional Euler equations in curvilinear coordinates. The Euler equations are discretized using numerical derivatives of the numerical flux vector for the Jacobians. Two direct solvers are formulated, one of which has a diagonal plane matrix structure with significantly lower memory requirements. The direct solvers are used as a benchmark in measuring the convergence rate and robustness of more computationally efficient solvers which include two factored approaches, a Newton-relaxation algorithm and a discretized Newton-relaxation algorithm, which uses numerical Jacobians. A diagonal plane formulation for the Newton-relaxation algorithms has also been developed that may have the potential for massive parallelization. It is demonstrated that the Newton-relaxation approach can give convergence rates and robustness equal to that of a direct solver for three-dimensional problems. As a demonstration of the robustness of both the Newton-relaxation algorithm and numerical Jacobians, quadratic convergence to machine zero is demonstrated
The intersection of the perfective and imperfective domains: a corpus-based study of the grammaticalization of korean aspectual markers

Using diachronic corpus data, this article examines the grammaticalization of three Korean aspectual markers, progressive ‑ko iss‑, resultative ‑e iss‑, and anterior ‑ess‑. It demonstrates that the three Korean aspectual markers emerged from the same source ‑e is(i)‑, which in the 15th C expressed both resultative and progressive meanings. This finding goes against Bybee, Perkins, and Pagliuca’s (1994) proposition that perfective and imperfective markers follow separate grammaticalization paths. In addition, the finding confirms that Shirai’s (1998) proposal about the murky distinction between perfective and imperfective domains also holds true in the diachronic development of aspectual markers.
Eflornithine treatment in SHR : potential role of vascular polyamines and ornithine decarboxylase in hypertension

This study was performed to assess the potential role of polyamines in the alterations in vascular structure and function in spontaneously hypertensive rats (SHR). The effects of chronic administration of eflornithine (α-difluoromethylornithine; DFMO), a highly specific inhibitor of ornithine decarboxylase (the rate limiting enzyme in polyamine biosynthesis), on vascular polyamine contents, vascular structure and function, and blood pressure was studied. Male SHR (16-17 weeks of age) with an average systolic blood pressure (SBP) of 161 ± 3 mmHg were used. The rats were divided into two groups and received either tap water or a 1% DFMO solution to drink for 6 weeks. SBP and body weight were recorded prior to and once-a-week during the experiment. Standard in vitro vascular reactivity studies on ring segments of aorta and tail artery were performed. Ring segment weight, arterial medial thickness, and vascular polyamine contents were also determined. Body weights were not significantly affected by the DFMO t...
Modeling of fluid filtration and near-wellbore damage along a horizontal well

Abstract A method was developed to simulate drilling fluid invasion of a two-phase system (water-based mud in an oil-bearing formation) and to subsequently evaluate the damage along a horizontal well. The proposed model includes fluid invasion, filter cake buildup, and relative permeability components. Filter cake and mud filtration models were developed based on a mass balance equation of cake deposition and erosion and Darcy's equation. A convection–dispersion equation was solved numerically to characterize filtrate invasion. Exposure time, permeability anisotropy, and various formation properties are considered as factors causing non-uniform fluid invasion in horizontal wells. The results of the simulation provide the distribution of fluid filtrate and indicate the maximum invasion depths and the degree of fluid invasion around the wellbore. Coupling these results with relative permeability curves allows the assessment of the distribution of effective permeabilities. The effective permeability distribution and the depth of invasion are the keys to estimating the damage caused by fluid invasion. Damage radius and skin factor predicted by the model are in agreement with published results. Overall, this method provides improvement of fluid filtrate characterization and estimation of damage along a horizontal well.
The Curious Role of Natural Kind Terms

The semantics of natural kind terms has recently been seen as a problem of reference. Kripke and Putnam have suggested that their meaning begins with rigid designation, with any further implications emerging after empirical study. I part ways with this approach and instead offer an account that focuses on the contribution that these terms make to the inferential roles of different sorts of sentences. I note that natural kind terms play an odd array of grammatical roles, both as subject and as parts of predicates, and explain why this dual role contributes something pragmatically significant to explanations of natural phenomena.
Instrumentation and Method for Ultrahigh Resolution Field Desorption Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry of Nonpolar Species

We describe the construction and application of a 9.4-T FT-ICR mass spectrometer interfaced to a commercial field desorption ion source for high-resolution, high-mass accuracy measurements of nonpolar species. The FT-ICR MS instrument includes a liquid injection field desorption ionization source, octopole ion guides, external octopole ion trap capable of an axial potential gradient for ion ejection, capacitively coupled open cylindrical ion trap, and pulsed gas valve for ion cooling. Model compound responses with regard to various source and instrument conditions provide a basis for interpretation of broadband mass spectra of complex mixtures. As an example, we demonstrate broadband speciation of a Gulf Coast crude oil, with respect to numerous heteroatomic classes, compound types (rings plus double bonds), and carbon number distributions.
The effect of biodiesel oxidation on engine performance and emissions

Abstract Biodiesel is an alternative fuel consisting of the alkyl monoesters of fatty acids from vegetable oils or animal fats. Previous research has shown that biodiesel-fueled engines produce less carbon monoxide, unburned hydrocarbons, and particulate emissions compared to diesel fuel. One drawback of biodiesel is that it is more prone to oxidation than petroleum-based diesel fuel. In its advanced stages, this oxidation can cause the fuel to become acidic and to form insoluble gums and sediments that can plug fuel filters. The objective of this study was to evaluate the impact of oxidized biodiesel on engine performance and emissions. A John Deere 4276T turbocharged DI diesel engine was fueled with oxidized and unoxidized biodiesel and the performance and emissions were compared with No. 2 diesel fuel. The neat biodiesels, 20% blends, and the base fuel (No. 2 diesel) were tested at two different loads (100 and 20%) and three injection timings (3° advanced, standard; 3° retarded). The tests were performed at steady-state conditions at a single engine speed of 1400 rpm. The engine performance of the neat biodiesels and their blends was similar to that of No. 2 diesel fuel with the same thermal efficiency, but higher fuel consumption. Compared with unoxidized biodiesel, oxidized neat biodiesel produced 15 and 16% lower exhaust carbon monoxide and hydrocarbons, respectively. No statistically significant difference was found between the oxides of nitrogen and smoke emissions from oxidized and unoxidized biodiesel.
Vasculature of the fish gill: Anatomical correlates of physiological functions

The fish gill is a multifunctional organ responsible for respiration, osmoregulation, acid base balance, nitrogen excretion, and metabolism of circulating hormones. Two or more microcirculatory systems subserve these activities and form one of the most complex vascular networks found in any vertebrate. In this article the vascular anatomy of the teleost gill and the role of gill vessels in mediating physiological function are examined. Vascular corrosion replication techniques have been instrumental in resolving the spatial organization of gill microcirculation. Variations in the replication procedures provide information on the interrelationships between the vascular pathways, factors that govern flow distribution, and the physical characteristics of the vessels themselves. Anatomically, gill vessels are as diverse as their physiological functions. Pillar cells, unique to the fish gill, form the lining of the respiratory vasculature and may have substantial metabolic effects on circulating hormones. The non-respiratory pathways appear to be lined with both typical and unusual endothelial cells, although the fine structure and function(s) of these vessels are largely unknown. To date most of the information on gill vessels has been derived from descriptive morphological studies. Further evaluation of the anatomical and physiological correlations of these tissues is predicated upon the application of histocytochemical, morphometric, and other quantitative methodologies as well as an examination of gills from fish with various evolutionary and environmental backgrounds.
Twenty-five years of research in the analysis of archaeological artifacts and works of art

Abstract Twenty-five years of research in the analysis of archaeological and art historical materials at Brookhaven have taught us that the success of a large collaborative project depends on close cooperation and detailed advance planning between the archaeologist or art-historian and the scientists. On the more practical level, the value of such projects to future research workers is critically dependent on the planning and implementation of data banks. Finally, more research needs to be done, especially in trace element analysis, on problems of standardization.
The influence of time stress and location on behavioral warning compliance

Abstract Stress has been shown to affect perceptual processing and decision making in various domains. Two experiments examined the effect of stress on compliance behavior. The first experiment also examined the effect of warning location. In Experiment 1, participants were assigned randomly to one of four conditions in a 2 (stress)×2 (warning placement) between-subjects design. Participants performed a chemistry task in which they weighed and measured various chemical substances that appeared potentially hazardous, but were actually safe. In the high stress condition, participants were given a time limit to complete the task, and the experimenter stood immediately adjacent to the participant, appearing to be monitoring the participant's performance. In the low stress condition, participants were given as much time as they needed to complete the task and the experimenter stood at a distance, out of the participant's field of view. A warning to wear mask and gloves was present in one of two locations, either as a posted sign or placed within a set of task instructions. Compliance with the warning (wearing of protective equipment) was significantly higher among participants who were under low stress and exposed to the within-instructions warning. In Experiment 2, the stress manipulation was separated into two factors: time pressure (absence vs presence) and social monitoring (absence vs presence). Results showed that time pressure significantly reduced compliance compared with its absence, but social monitoring produced a small but non-significant compliance enhancement. The results point to the need to consider external factors in warning systems.
A new conceptual model for cyclones generated in the lee of the Rocky Mountains

When a shortwave trough moves eastward over the Rocky Mountains and into the central United States, the following important features may form: a drytrough (i.e., a lee trough that also has the characteristics of a dryline), an arctic front, a low-level jet, and two synoptic-scale rainbands (called the cold front aloft rainband and the pre-drytrough rainband) that can produce heavy precipitation and severe weather well ahead of the drytrough. These features are incorporated into a new conceptual model for cyclones in the central United States. Use of this model can aid the interpretation of observational data and numerical model output, and it may also help to improve short-range forecasting in the central United States.
Interdisciplinary teamwork for hip fracture prevention.

Abstract This article discusses the roles of various interdisciplinary team members, such as physicians, dietitians, physical therapists, social workers, activity therapists, and nursing staff, whose combined expertise is necessary to prevent hip fractures in nursing homes. To be successful, these professionals must be aware of and respect the roles of all team members, consistently identify the risk factors associated with hip fracture, and implement, evaluate, and modify interventions on an individual basis. (Geriatr Nurs 1999;20:293-6)
Superconductivity in Metal-Semiconductor Eutectic Alloys.

The superconductivity of several metal-semiconductor simple eutectic alloys containing Ge or Si, and one of the metals Al, Be, In, Pb, Sn, or T1 has been investigated. The liquid-quenching technique was used to reduce the characteristic scale of the microstructure in the alloys. It was found in some cases (notably Al-base alloys) that the superconducting transition temperature of the metallic phase was significantly enhanced (from 1.2[degrees]K to ~ 6[degrees]K for Al-base alloys) as a result of liquid-quenching. The characteristic scale of the microstructure was found to be of the order of several hundred angstroms in alloys showing the greatest enhancement effect. The results are discussed in terms of recent theoretical models that predict enhancement of superconductivity due to electronic interactions at a metal-semiconductor interface. The results are also analyzed in terms of the McMillan theory of superconductivity in which the enhancement effect is attributed to a reduction in the characteristic phonon frequencies of the metal. It is concluded that the latter explanation can account for all of the observed properties and, thus, that it is probably unnecessary to invoke an "excitonic mechanism" to explain the results.
The ethical and legal implications of handheld medical computers.

(2001). THE ETHICAL AND LEGAL IMPLICATIONS OF HANDHELD MEDICAL COMPUTERS. Journal of Legal Medicine: Vol. 22, No. 4, pp. 447-466.
Phylogenetic analysis of the N8 neuraminidase gene of influenza A viruses

Abstract Phylogenetic analysis of the N8 neuraminidase (NA) genes from 18 influenza A viruses, representing equine and avian hosts in different geographic locations, revealed three major lineages: (i) currently circulating equine 2 viruses; (ii) avian viruses isolated in the Eurasian region, including A/Equine/Jilin/1/89, a recent avian-like N8 isolate found in horses in China; and (iii) avian viruses isolated in North America. Comparison of mutation rates indicated that avian N8 genes have evolved more slowly than their equine counterparts. That is, in both avian lineages, 72% of the nucleotide changes were silent in the terminal branches of the phylogenetic tree, whereas in equine 2 viruses, 59% of the nucleotide changes were silent. This suggests greater selective pressure on the NA gene from the mammalian immune system, leading to progressive evolution. Alternatively, the slower mutation rate for avian N8 genes could reflect a selective advantage gained from a longer, continuous span of evolution. The shape of the phylogenetic tree, the evolutionary rate, and the calculated date of origin for the N8 equine 2 virus lineage were comparable to findings for the equine 2 virus hemagglutinin (HA) gene (Bean et al, J. Virol 66, 1129-1138, 1992). This suggests that both viral membrane glycoproteins of equine 2 viruses have evolved together and have been subjected to similar levels of selective pressure. Several amino acid residues were found to differ among the three host-specific lineages, but they may not be involved in host restriction of the NA, as they are shared by EQ/Jilin/1/89 and viruses of avian origin. The present findings complement detailed structural information on the N2 and N9 subtypes and should prove valuable in understanding future X-ray diffraction studies of N8 crystals.
Genetic and nongenetic factors in expression of infectious murine leukemia viruses in mice of the DBA/2 × RF cross

Abstract Mice of the RF and DBA/2 strains possess endogenous ecotropic murine leukemia virus (E-MuLV) genomes but express only low to undetectable levels of infectious virus in their lymphoid tissues. F1 mice of this cross showed high levels of infectious E-MuLV if DBA/2 was the maternal parent but very low levels if RF was the maternal parent. E-MuLV expression, if present, was always higher in the spleen than in the thymus. Studies of reciprocal backcross generations with both parental strains indicated that the presence of the virus was governed by a single dominant autosomal locus present in the RF strain, and that RF females, but neither RF males nor DBA/2 females or males, transmitted a non-Mendelian factor which powerfully suppressed virus expression in their progeny. Some but not all (DBA/2♀ × RF♂)F1 females also possessed the capacity to transmit this maternal suppression to their progeny. Xenotropic murine leukemia virus (X-MuLV) showed a different pattern of expression in this cross. In the thymus it was detected in a minority of DBA/2 and in no RF mice; in crosses the presence of X-MuLV in this organ was independent of the presence of E-MuLV. In the spleen, X-MuLV was detected only in a percentage of E-MuLV-positive mice. The maternal factor from RF mothers which suppressed E-MuLV did not suppress thymic expression of X-MuLV. Skin painting with 3-methylcholanthrene induced a high incidence of thymic lymphoma in mice of both parental strains and in F1 hybrids, all of which normally show only low incidences of the diseases; the treatment did not induce markedly increased expression of E-MuLV or X-MuLV in mice of either parental strain, although it did abrogate the diminution of E-MuLV titers seen with age in (DBA/2♀ × RF♂)F1 mice beyond the age of three months.
Student IT services to support open source software for humanity

Student involvement in Humanitarian Free and Open Source Software holds the potential to attract students to computing majors. The HumIT project is investigating how IT students can provide IT infrastructure services to users of such applications. This poster reports on the status of the HumIT project and some initial results.
Continuous inertial confinement fusion for the generation of very intense plasma jets

1407_38The attainment of high densities in inertial confinement fusion is reached through the coalescence of convergent waves in time. According to the laws of gas dynamics there exists a corresponding solution where the coalescence takes place instead in space. Applied to inertial confinement fusion, this solution may provide a configuration for a continuous plasma focus. If such a configuration can be upgraded to yield a net release of thermonuclear energy, the generation of very intense plasma jets may become possible.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.