cssi/SciSciGPT-SciSciNet huggingface dataset:
An experimental investigation of T-beam stability under bending

This paper presents an experimental setup used to study the response and stability of T-beams subjected to pure bending. The setup consists of a four-point bending device instrumented to measure the moment and curvature in the beam. Special grips are used to attach the specimens to the bending device and enforce a no-twist condition at the ends of the beams. A special instrument is used to measure deformations induced by buckling along the axis of the beam. Results are presented for the cases of monotonic and cyclic bending of short beams that buckle in a local mode. The results indicate that the lateral deflection of the web of the beams develops a ripple relatively early in the bending process. Local buckles arise from localization of the amplitude of the ripple at a given point along the specimen.
British and Irish Toponyms in the South Atlantic States

Abstract Toponymic patterns of 542 features in the South Atlantic states confirm the commonly accepted view of historians and geographers that the coastal plain was dominated by English settlers and the backcountry was settled largely by Celtic immigrants from the fringes of the British Isles. Many toponyms were transferred directly while others were based upon the names of the British royal family.
Environment, manufacturing technology, and embedded knowledge

This article focuses on the relationship between different types of organization-based knowledge and its application to utilizing various forms of advanced manufacturing technology. Explicit knowledge is transparent in the sense that any firm with a comparable skill and technology base can understand and apply it in a fast and similar manner. Tacit knowledge is based more on insight, practice, and cumulative learning that is deeply embedded within the organization's dynamic routines and operating systems. The effective learning and application of new types of manufacturing skills and techniques, such as computer-integrated manufacturing (CIM) and flexible manufacturing systems (FMS), is based heavily on the firm's cultivation of tacit, embedded knowledge to build competitive advantage. A model describes the strategic application of different manufacturing technologies across varying levels of technological change and market fragmentation. In each of the four cells, the roles of workers, managers, and different subunits of the firm are discussed as they relate to understanding the nexus between types of knowledge and manufacturing activities.
Magnetized Fokker–Planck equation with quasilinear diffusion for nonaxially symmetric velocity distribution functions

The kinetic equation governing the evolution of a nonaxially symmetric velocity distribution function of plasma particles in a uniform magnetic field, including the effects of collisions as well as quasilinear diffusion, is presented and analyzed. It is shown that, if the test particles’ orbits are straight lines, the kinetic equation reduces to a standard Fokker–Planck form with friction, collisional diffusion, and quasilinear diffusion coefficients all expressible in terms of scalar potentials. These potentials are simple generalizations of Rosenbluth potentials and can easily be used in numerical solutions of the Fokker–Planck equation.
Thrombospondin Type 1 Repeats Interact with Matrix Metalloproteinase 2 REGULATION OF METALLOPROTEINASE ACTIVITY

Thrombospondins are thought to function as inhibitors of angiogenesis. However, the mechanism(s) of this activity is not well understood. In this study, we have used the yeast two-hybrid system to identify proteins that interact with the thrombospondins 1 (TSP1) and 2 (TSP2) properdin-like type 1 repeats (TSR). One of the proteins identified that interacted with both TSR was matrix metalloproteinase 2 (MMP2). The isolated MMP2 cDNA clone encoded amino acid residues 237-633, which include the fibronectin-like gelatin binding region flanking the catalytic center and the carboxyl hemopexin-like region. Further testing of this clone demonstrated that the TSR interacted with the NH(2)-terminal region of the MMP2 that contains the catalytic domain. The protein interaction observed in yeast was further demonstrated by immunoprecipitation and Western blotting using purified intact TSP1, TSP2, MMP2, and MMP9. Although MMP2 interacted with TSP1 and TSP2 via its gelatin-binding domain or a closely mapping site, neither TSP1 nor TSP2 was degraded by MMP2 in vitro. Tissue culture and in vitro assays demonstrated that the presence of purified TSR and intact TSP1 resulted in inhibition of MMP activity. The ability of TSP1 to inhibit MMP3-dependent activation of pro-MMP9 and thrombin-induced activation of pro-MMP2 suggests that the TSPs may inhibit MMP activity by preventing activation of the MMP2 and MMP9 zymogens.
Profit-based resource planning

Summary form only given. Recent developments in the electric power utility industry restructuring provide flexible options for generation resource planning in a competitive electricity market is discussed. This presentation provides a model to analyze and remedy the existing conflicts for generation resource planning in restructured power systems. The objective of the generation resource planning model is to maximize the total expected profit of individual GENCOs over a planning horizon. The proposed algorithm will examine possible sites and markets for new generators, various unit types and capacities (such as gas, hydro, oil, coal, combined cycle), timing for the addition of new units, steps for the closure of old generators, generation scheduling of potential units, and strategies for the timely returns on investment.
The Mechanism of Queen Regulation of Foraging by Workers in Paper Wasps (Polistes fuscatus, Hymenoptera: Vespidae)

We examined how queens of the primitively eusocial wasp, Polistes fuscatus, stimulate foraging by workers in 10 small, post-worker-emergence field colonies. We experimentally increased colony needs, including needs of the brood, by removing a colony's most active foragers (thereby decreasing the colony's foraging rate), and found that the queen significantly increased both her level of activity and rate of aggressive interactions. Most aggressive interactions were directed at dominant workers. Removal of a colony's least active foragers, however, produced no such effect. Our results, together with those of Reeve & Gamboa (1983, 1987), indicate that queens are sensitive to brood needs, and that they behaviorally regulate worker foraging to match brood needs by increasing their level of activity and rate of aggressive interactions.
A new instrument for measuring settling velocities in situ

Abstract An in-situ settling cylinder for determining particle settling velocities has been deployed during a field experiment in San Pablo Bay, California. The instrument is a spring-loaded cylinder which traps approximately 31 of water and suspended sediment between two end plates. Mounted between the end plates is a vertical array of five miniature nephelometers, positioned 4–20 cm below the top end plate, which continuously monitor (5 Hz sampling rate) suspended sediment concentration at each level as particles settle. The resulting settling curve can be divided into components with characteristic settling velocities and a settling velocity distribution obtained for the suspension. The results are conservative estimates of settling velocities for the suspension. In-situ estimates of particle settling velocity are higher than Stokes settling velocities calculated for the disaggregated grain-size distribution of a suspended sediment sample, indicating that the sediment in suspension is in the form of aggregates. The aggregates have settling velocities as high as those of sand size quartz spheres.
Deterministic global optimization and torsion angle dynamics for molecular structure prediction

Abstract The problem of protein folding has become the subject of intense theoretical and experimental study over the past few decades. This work presents a new method for protein structure prediction using distance and dihedral angle restraints derived from NMR data. Both the formulation and solution approach differ substantially from traditional molecular structure prediction techniques. The traditional formulation is recast as a constrained global optimization problem whose solution is obtained through the use of the αBB algorithm, a deterministic global optimizationa approach suitable for nonconvex constrained problems. To enhance the efficiency of this method, torsion angle dynamics is introduced as an integral part of the solution approach. The proposed algorithm is tested on the Compstatin structure prediction problem.
Automatic sorting of ichthyoplankton; Factors controlling plankton density in gradients of silica

Following isopycnic sedimentation in density gradients of colloidal silica (Ludox AM), zooplankton segregated into 3 broad bands of increasing density which included, respectively, fish eggs, invertebrates, and fish larvae. The zone of fish eggs was contaminated with Sagitta spp. and the zone of fish larvae was overlapped partially by mysids and euphausids. We have sought to minimize contamination through modifications of the silica gradients which might shift banding densities of the ichthyoplankton or of the contaminating invertebrates. Density shifts in fact occurred in different commercial formulations of silica sols and in gradients modified by small amounts of polymers, osmotica or charged small molecules. Sagitta were specifically shifted out of the zone of fish eggs by the addition, of 1% w/v dextran sulfate or in a silica sol composed of very small particles of silica (Nalcoag 1115). Fish larvae were shifted to higher densities by the addition of 1% w/v trimetaphosphate or 1% w/v dextran sulfate. Additions of 1% w/v polyvinyl alcohol, and of 10 mM glycine, and potassium phosphate had intermediate effects. The same banding densities of plankton in silica gradients were reached in less than 10 h at one gravity, independent of the immediate pretreatment of the sample.
Aerodynamic stability of a truss-stiffened cable-stayed bridge

Abstract Wind tunnel tests have been conducted to evaluate the aerodynamic stability of a proposed design for a truss-stiffened cable-stayed bridge. The tests were performed in an open-circuit laminar flow wind tunnel using a 1:60 scale section model representing a 300-ft (91.46-m) segment of the main span. Wind speeds up to and beyond the design speed of 150 mph (240km/h) were simulated as were wind angles ranging from −4 to +6 degrees. Under these conditions, the bridge section exhibited little or no tendency toward vertical motion. The bridge model does, however, demonstrate a sensitivity to vortex-induced torsional vibrations over the full range of wind angle. In addition, the section model ultimately becomes unstable due to single degree-of-freedom flutter in torsion.
Predicting Whether Multiculturalism Positively or Negatively Influences White Americans’ Intergroup Attitudes: The Role of Ethnic Identification:

Multiculturalism, or the belief that racial and ethnic differences should be acknowledged and appreciated, has been met with both positive reactions (e.g., decreased prejudice) and negative reactions (e.g., perceptions of threat) from dominant group members. The present research proposes that multiculturalism can either positively or negatively influence White Americans’ intergroup attitudes depending on their degree of ethnic identification. In Studies 1 and 2, White Americans primed with multiculturalism exhibited higher social dominance orientation (Study 1) and greater prejudice (Study 2), especially when they identified strongly with their ethnicity. In Study 3, perceptions of threat to group values were found to mediate the relation between multiculturalism, ethnic identification, and prejudice among White Americans. The results are discussed in terms of their implications for threat perceptions, ethnic identification, and conceptions of diversity.
Angle-resolving photoelectron energy analyzer: Mode calculations, ray-tracing analysis and performance evaluation

Abstract This paper describes comprehensive input-lens analysis, ray-tracing studies, empirical mode tests and performance evaluation for a Kuyatt—Simpson-type photoelectron energy analyzer. The analyzer has been designed specifically for angle-resolved photoemission studies using synchrotron radiation. Several operating modes are established using a computer code which combines matrix-optics techniques with ray tracing and least-squares analysis. The code is used to calculate the optimum input-lens voltages required to achieve a prescribed resolution at constant transmission. The modes are also established empirically and are characterized by computer ray-tracing. Performance tests conducted using synchrotron radiation demonstrate that the analyzer is capable of obtaining high-resolution (50 meV) angle- resolved (± 1.5°) photoelectron spectra at good counting rates (∼ 10 kHz) without multichannel detection.
THE BEHAVIOR OF RIGID AND SEMI-RIGID BIDENTATE DONOR MOLECULES TOWARD SOME SIMPLE BORON ACCEPTORS

Abstract Synthesis of a series of complexes of the type LLBX2 + BX4 − where X = F− and CI− and LL = 1,10-phenanthroline, 2,2′-bipyridine and 1,8-bis(dimethylamino)naphthalene was achieved by the direct interaction of the ligand and BX3. No reaction was observed for X = CH3. The reactions provide a direct route for the preparation of tetra-coordinate boronium cations. The boron-11 nmr and infrared spectra of these complexes confirm the ionic nature of the compounds. 2,2′-Bipyridine functions as a chelating agent rather than as a bis-monodentate donor. 1,8-Bis(dimethylamino)naphthalene is found to be able to chelate cations much larger than protons. The steric implications of donor-acceptor interactions of boron with rigid and semi-rigid chelating donor molecules are discussed.
Genetic defects in the hotspot of inwardly rectifying K+ (Kir) channels and their metabolic consequences: A review

Inwardly rectifying potassium (Kir) channels are essential for maintaining normal potassium homeostasis and the resting membrane potential. As a consequence, mutations in Kir channels cause debilitating diseases ranging from cardiac failure to renal, ocular, pancreatic, and neurological abnormalities. Structurally, Kir channels consist of two trans-membrane domains, a pore-forming loop that contains the selectivity filter and two cytoplasmic polar tails. Within the cytoplasmic structure, clusters of amino acid sequences form regulatory domains that interact with cellular metabolites to control the opening and closing of the channel. In this review, we present an overview of Kir channel function and recent progress in the characterization of selected Kir channel mutations that lie in and near a C-terminal cytoplasmic ‘hotspot’ domain. The resultant molecular mechanisms by which the loss or gain of channel function leads to organ failure provide potential opportunities for targeted therapeutic interventions for this important group of channelopathies.
Evaluating the Environmental Impact of Alternative-Fuel Vehicles

Abstract Using a dynamic microsimulation model, I investigate total emissions in the Los Angeles area as electric, compressed natural gas (CNG), and methanol vehicles are introduced under various pricing conditions. Price reductions for alternative-fuel vehicles lead to reductions in total emissions despite the usage tradeoffs that households make between limited-range vehicles and older gasoline vehicles. Price reductions for CNG vehicles are as effective at reducing emissions as price reductions for electric vehicles. Overall, the introduction of CNG and methanol vehicles lead to health benefits of between $20 and $120 million (depending upon the year) while the introduction of electric vehicles brings additional benefits of between $3.5 and $70 million per year.
Quantitative mechanistic studies of the photoreactions of trinuclear metal carbonyl clusters of iron, ruthenium and osmium

Abstract Reviewed are quantitative investigations of the solution phase photochemical reaction mechanisms of M3 carbonyl clusters of the iron triad metals. A unified model is presented for the photoreactions of the unsubstituted clusters M3(CO)12.
Same-sex Versus Other-sex Best Friendship in Early Adolescence: Longitudinal Predictors of Antisocial Behavior Throughout Adolescence

This study examines the relationship between having other-sex versus same-sex best friends and antisocial behavior throughout early adolescence. Participants (N = 955) were recruited in 6th grade and followed longitudinally through 7th, 8th, and 11th grades. Participants were 58% ethnically diverse youth and 48% girls. Results indicate that the frequency of other-sex best friendship remained stable from 6th to 7th grade but significantly increased from 8th to 11th grade. Higher rates of concurrent antisocial behavior were related to having other-sex best friends in 6th grade but not in 7th grade. In 8th grade, there was an interaction between friendship and the sex of friends. Boys with only same-sex best friends and girls with other-sex best friends endorsed higher rates of antisocial behavior. Having other-sex best friends predicted antisocial behavior from 6th to 7th grade and 8th to 11th grade, especially for girls. Implications for the development of early adolescent friendship and antisocial behavior are discussed.
The consequence of soiling on PV system performance in Arizona; Comparing three study methods

We study the consequence of soiling on different flat-plate photovoltaic modules in Tucson, Arizona. We compare three different methods of study. These methods include (1) a comparison of energy yields between strings of PV modules, held at MPP, that are regularly cleaned and naturally soiled, (2) measurement I-V curves from individual PV modules in the field before and after cleaning, and (3) measurement I-V curves from individual PV modules in the laboratory before and after cleaning using a flash tester. All methods indicate an approximate 1% performance enhancement from cleaning. Laboratory I-V curve measurements provide the most precise results.
Clinical stage T1c prostate cancer: pathologic outcomes following radical prostatectomy in black and white men.

BACKGROUND The incidence of prostate cancer in black men is 50% to 70% higher than among age-matched white men. Black men have a twofold higher mortality rate and overall tend to have higher serum prostate-specific antigen (PSA) levels than white men. To determine whether racial differences exist in men whose prostate cancer was diagnosed based solely on an elevated serum PSA level, we compared clinical and pathologic features in black and white men undergoing radical prostatectomy (RP) for clinical stage T1c prostate cancer. METHODS We used a prospectively collected database to identify all men undergoing RP for clinical T1c prostate cancer between July 1995 and October 2000. A total of 129 consecutive men (56 black men and 73 white men) were compared for age at diagnosis, serum PSA level, biopsy Gleason score, pathologic stage, RP specimen Gleason score, incidence of lymph node metastasis, and incidence of positive surgical margins. RESULTS Statistically significant differences were not found by race in patients' ages, serum PSA levels, biopsy Gleason score, pathologic stage, incidence of lymph node metastases, or incidence of positive surgical margins. The RP specimen Gleason score was more heterogeneous in black men than white men (P = 0.02). CONCLUSIONS Racial differences in the incidence and mortality rate of prostate cancer are well known, but differences in the clinical and pathologic features between black and white men with prostate cancer identified solely based on an elevated serum PSA level with negative results on digital rectal examination (clinical stage T1c ) have been poorly studied. Our results suggest that men with clinical stage T1c prostate cancer have similar clinical and pathologic findings regardless of race. These results suggest that early-detection programs using serum PSA testing for prostate cancer in black men potentially can result in improvements in prostate cancer outcomes in this high-risk group. Prostate 50: 236–240, 2002. © 2002 Wiley-Liss, Inc.
Coral reefs at risk

Eighty-eight percent of Southeast Asia's reefs are threatened by overfishing, destructive fishing, and sedimentation and pollution from inland activities, according to a new report by 35 regional scientists published by the World Resources Institute. Nearly 100,000 square kilometers of coral reefs—34% of the world's total—are located in Southeast Asia.
Military Spending and the US Defense Industry: Regional Patterns of Military Contracts and Subcontracts

Military expenditure is the largest category of discretionary spending in the US federal budget. As such, its spatial patterns are also among the most concentrated. An analysis of recent defense spending data indicates that ten to fifteen states receive between them at least 70% of military contracts, and higher proportions of high-technology and research-related contracts. Examination of subcontracting data reveals that little wider dispersion of defense spending occurs to states outside the core areas in the West, on the East Coast, and in a few interior locations.
FIELD OF AN ALTERNATING MAGNETIC DIPOLE ON THE SURFACE OF A LAYERED EARTH

The magnetic field near a vertical alternating magnetic dipole on the surface of a layered earth is computed for points on the surface. In the layer the dimensionless conductivity parameter is assumed to take the values 0, 14, 1, and 4; in the homogeneous substratum, this parameter is assigned the values 0, 14, 1, 4, and infinity. The induced field is computed at distances from the source 12, 1, 2, 4, 8, and 16 times the layer thickness.
Force on an atom in an electrostatic field: Feynman-Hellmann theorem and oscillator strengths

The force on a free atom or ion in a uniform electrostatic field is considered in the framework of the Feynman-Hellmann theorem. The contributions to the force from excited states are shown to be given directly by the "oscillator strengths" between these states and the occupied states in the atom or ion. Force calculations for atoms in molecules and solids are discussed in the light of these results. In the case of current carrying solids, the Feynman-Hellmann theorem is not applicable, yet the force expression for an ion in the solid retains the Feynman-Hellmann form. Because of this distinction, arguments based on local neutrality of an ion in a solid are relevant for an isolated solid but not for a current carrying solid. A previously derived sum rule for the force on the ions of a conducting solid is shown to be a statement of the oscillator-strength sum rule.
Partial characterization of peroxidase isoenzymes from rust-affected wheat leaves

Abstract Four anodic peroxidase isoenzymes from wheat leaves were purified by column chromatography and their kinetic behavior with common substrates were examined. One isoenzyme is more active in wheat resistant to stem rust fungi and differed from the others in carbohydrate content and also by a specific activity 2–4-fold higher with non-physiological electron donors. As a substrate, eugenol exhibited kinetic behavior different from p -phenylenediamine, guaiacol or o -dianisidine with all isoenzymes. All four isoenzymes showed similar pH and temperature optima and kinetic behavior and apparent K m values for both H 2 O 2 and non-physiological electron donors.
Estimating willingness-to-pay for housing attributes an application to Cairo and Manila

Abstract This paper obtains willingness-to-pay estimates for housing characteristics in two cities of the Third World. The analysis estimates housing demand, using household bid-rent functions and, following Wheaton (Journal of Urban Economics, 1977, 4, 200-217), obtains marginal willingness-to-pay approximations for specific housing attributes for different tenure groups and household types. These estimates can be used to design housing programs which provide better and more appropriate types of shelter to different types of households in Cairo and Manila. In addition, the empirical findings generally support current thinking regarding housing policies in developing countries. In particular, low-income households appear to place a great deal of value on locations which are close to their place of employment or the CBD, have access to a regular source of potable water, and are close to public transportation.
Protein synthesis in tonic and phasic skeletal muscles.

LITTLE is known of the way in which physiological function influences protein metabolism in muscle. Knowledge in this area is essential if we are to understand the biochemical mechanisms through which use and disuse alter muscle size and functional capacity. The present studies were undertaken to see if the level of protein synthesis in different skeletal muscles varies systematically with different types of physiological activity.
CYCLIC HETEROPHYLLY IN SYNGONIUM (ARACEAE)

Species in the genus Syngonium germinate on the ground and mature on the trunks of the trees. These vines consist of relatively unbranched shoots which grow through the forest for considerable distances both horizontally and vertically. In the three species of this study, the shape of the segment, measured as internode diam/length, falls into two distinct classes, leafy and elongate, and varies cyclicly along single shoots. Two cycles are recognized. One cycle occurs in small diam terrestrial shoots in which cycling seems to be controlled by endogenous factors, and occurs with a period of a few tens of segments. The other cycle occurs in shoots of larger diam which climb and descend from trees. In this cycle, alternation between the two forms is controlled by gain or loss of contact with trees, and shoots may remain within a phase of the cycle for hundreds of segments, as long as the substrate does not change. SYNGONIUM (Araceae) is a monocotyledonous genus of herbaceous vines of neotropical lowland rain forests. Vines are unusual in that they have developed to a high degree, a faculty otherwise rare among plants, the ability to move. Seeds of Syngonium germinate on the ground, yet the plant becomes sexually reproductive high on the trunks of sometimes distant trees. An important aspect of the biology of Syngonium is that the germination site of the plant may be a great distance (relative to its size),
Autotelic need for touch, haptics, and persuasion: The role of involvement

Previous research has shown that a touch or haptic element attached to a persuasive appeal can increase persuasion, particularly for individuals who have a clear preference for touch to enjoy its sensory feedback (high autotelics). This research extends previous work by including involvement in the context of an appeal by a nonprofit. We find, in an experiment where we manipulate involvement, that when a haptic element is present, high autotelics are more persuaded regardless of their involvement with the message. However, for low autotelics, a haptic element increases persuasion under conditions of low versus high involvement with the message. A second experiment measures involvement and finds that again, under low involvement conditions, both high and low autotelics are persuaded by a touch element. Finally, a field study with a local symphony orchestra is conducted in which involvement with the message is low but involvement with the company is high. In this case, a touch element is only persuasive for high autotelics. © 2011 Wiley Periodicals, Inc.
Investigation of Chemical/Mechanical Polishing of Niobium

A chemical/mechanical method for polishing flat niobium sheets to a mirror finish was developed. Various polishing slurries with different open circuit potentials and pH values were considered. All slurries fell within the niobate region of the Pourbaix diagrams, indicating that slurries are in a thermodynamically stable region. Oxidation characteristics of the niobium in the various slurries were determined by XPS and confirmed previously published work that niobium forms various layers of stable niobium oxides roughly 4.5–4.7 nm in thickness on the surface. A multi-step polishing method that relies on mechanical abrasion of the surface proved to be effective, and particles of different hardness and size were explored. Niobium wafers with initial peak-to-valley (PV) surface roughness of 3 to 7 μm were polished. The multi-step process utilized a slurry containing 1 μm diameter alumina particles to polish this initial roughness down to a submicrometer level. The final polish was provided by a slurry contai...
Oxford's Language learning strategies: What Every Teacher Should Know (Rebecca Oxford)

(1993). Oxford's Language learning strategies: What Every Teacher Should Know (Rebecca Oxford) Bilingual Research Journal: Vol. 17, No. 1-2, pp. 117-121.
The therapeutic potential of inhibitors of the signal transducer and activator of transcription 3 for central nervous system malignancies

BACKGROUND High-grade primary and metastatic central nervous system (CNS) tumors are common, deadly, and refractory to conventional therapy and continue to be therapeutically challenging. A key nodal transcriptional factor, the signal transducer and activator of transcription 3 (STAT3), drives the fundamental components of tumor malignancy and metastases in the CNS by enhancing proliferation, angiogenesis, invasion, metastasis, and immunosuppression. The introduction of STAT3 inhibitors in clinical trials for this patient population is imminent. METHODS STAT3 inhibitors have been extensively tested in a variety of preclinical murine models. RESULTS The STAT3 inhibitor, WP1066, has displayed marked efficacy with minimal toxicity against malignancy in murine models, including established intracerebral tumors. The mechanism of this in vivo efficacy of the STAT3 blockade agents is a combination of direct tumor cytotoxicity and immune cytotoxic clearance. CONCLUSIONS Given their direct antitumor cytotoxic effects, STAT3 inhibitors may exert therapeutic activity in the monotherapy setting but may also have compelling use as immunotherapeutic modulators or as a salvage therapy.
Gravitational separation of gases and isotopes in polar ice caps.

Atmospheric gases trapped in polar ice at the firn to ice transition layer are enriched in heavy isotopes (nitrogen-15 and oxygen-18) and in heavy gases (O2/N2 and Ar/N2 ratios) relative to the free atmosphere. The maximum enrichments observed follow patterns predicted for gravitational equilibrium at the base of the firn layer, as calculated from the depth to the transition layer and the temperature in the firn. Gas ratios exhibit both positive and negative enrichments relative to air: the negative enrichments of heavy gases are consistent with observed artifacts of vacuum stripping of gases from fractured ice and with the relative values of molecular diameters that govern capillary transport. These two models for isotopic and elemental fractionation provide a basis for understanding the initial enrichments of carbon-13 and oxygen-18 in trapped CO2, CH4, and O2 in ice cores, which must be known in order to decipher ancient atmospheric isotopic ratios.
Use of the polymerase chain reaction for the diagnosis of invasive Candida infection

Abstract Molecular biology has had a strong impact on the field of microbiology. Recently these methods have emerged from the laboratory and have been applied to the area of clinical microbiology. The polymerase chain reaction (PCR) is a method of DNA amplification that has been used primarily in the research setting to detect pathogens which are generally found at low levels, are difficult to culture, or are difficult to identify. The dilemma in identifying Candida species in the bloodstream during an episode of disseminated disease leads to a greater incidence of morbidity and mortality due to disseminated nosocomial candidal infections in the compromised hosts. Using PCR to detect low levels of Candida DNA in the bloodstream early, rapidly, and accurately especially when the blood cultures are still negative, can provide definitive information beneficial to the management of disseminated candidiasis. However, before a PCR-based test for candidaemia can be used in the clinical laboratory, several problems have to be resolved.
Role of surface charge of the blood vessel wall, blood cells, and prosthetic materials in intravascular thrombosis

Abstract Intravascular thrombosis is an interfacial reaction. One can therefore expect it to depend on the surface charge characteristics of the blood vessel wall, blood cells, and prosthetic materials. Electrokinetic methods (electroosmosis, streaming potentials, electrophoresis) have been used to determine these characteristics. The results of the experiments to date may be summarized as follows: (1) under normal conditions, the blood vessel wall and blood cells are negatively charged; (2) injury to the blood vessel wall reduces the magnitude of the negative charge density and very often even causes a reversal in the sign of the surface charge—injury is generally accompanied by thrombus formation; (3) a decrease in pH reduces the negative charge density of the blood vessel wall and of blood cells. The isoelectric point occurs at a pH of about 4.7; (4) antithrombogenic drugs increase the magnitude of the negative charge density, whereas thrombogenic drugs have the opposite effect and in many cases even reverse its sign; and (5) positively charged prosthetic materials are thrombogenic whereas negatively charged surfaces tend to be nonthrombogenic—the higher and the more uniform the negative charge density, the better is the chance of the materials being nonthrombogenic.
Effects of amphetamine exposure in adolescence or young adulthood on inhibitory control in adult male and female rats.

Heightened impulsivity is a feature of some psychiatric disorders, including addiction, that also have sex-specific patterns of expression. The relationship between addiction and impulsivity may be driven by drug-induced changes in behavior caused by long term adaptations in signaling within the medial prefrontal cortex (mPFC). Here, we used a response inhibition task that is sensitive to changes in mPFC function to examine the effects of sex and exposure to amphetamine (AMPH) on impulsive action and vigilance. We also examined drug-induced alterations in glutamatergic and dopaminergic signaling through challenge injections with the NMDA receptor antagonist MK-801 (dizocilpine) and AMPH. Male and female Sprague Dawley rats were injected (i.p.) with saline or 3 mg/kg AMPH every other day during adolescence (postnatal day (P) 27–45) or adulthood (P85–103). Starting on P125–135, rats were tested for their ability to lever press for a food reward during periods of signaled availability and withhold responding during a “premature response” phase. In experiment 1, rats received challenge injections (i.p.) of MK-801 and AMPH followed by tests of task performance and locomotor activity. In experiment 2, rats received intra-mPFC infusion of MK-801. We found that females had better inhibitory control and poorer vigilance than males and that AMPH exposure had both sex- and age-of-exposure dependent effects on impulsivity. Systemic drug challenges disrupted task performance, particularly in females, and increased impulsivity while intra-mPFC infusions had modest effects. AMPH exposure did not affect responses to drug challenges. Together, these results suggest that sex mediates both trait and drug-induced impulsivity.
PDF Cells Are a GABA-Responsive Wake-Promoting Component of the Drosophila Sleep Circuit

Daily sleep cycles in humans are driven by a complex circuit within which GABAergic sleep-promoting neurons oppose arousal. Drosophila sleep has recently been shown to be controlled by GABA, which acts on unknown cells expressing the Rdl GABAA receptor. We identify here the relevant Rdl-containing cells as PDF-expressing small and large ventral lateral neurons (LNvs) of the circadian clock. LNv activity regulates total sleep as well as the rate of sleep onset; both large and small LNvs are part of the sleep circuit. Flies mutant for pdf or its receptor are hypersomnolent, and PDF acts on the LNvs themselves to control sleep. These features of the Drosophila sleep circuit, GABAergic control of onset and maintenance as well as peptidergic control of arousal, support the idea that features of sleep-circuit architecture as well as the mechanisms governing the behavioral transitions between sleep and wake are conserved between mammals and insects.
The impact of school and college expenditures on the wages of southern and non-southern workers

Based on previous evidence of diminishing earnings returns to greater educational expenditures, the hypothesis that southern schools and colleges have greater returns than non-southern schools and colleges is tested but is not accepted. Per pupil expenditures for both school and college, however, significantly raise earnings for southern male full-time workers. The elasticity of expenditure with respect to the wage for high school graduates is 0.1212 for southerners and 0.0360 for non-southerners, and the elasticity for college expenditure is 0.0468 for southerners and 0.0260 for non-southerners.
User interactions in social networks and their implications

Social networks are popular platforms for interaction, communication and collaboration between friends. Researchers have recently proposed an emerging class of applications that leverage relationships from social networks to improve security and performance in applications such as email, web browsing and overlay routing. While these applications often cite social network connectivity statistics to support their designs, researchers in psychology and sociology have repeatedly cast doubt on the practice of inferring meaningful relationships from social network connections alone.This leads to the question: Are social links valid indicators of real user interaction? If not, then how can we quantify these factors to form a more accurate model for evaluating socially-enhanced applications? In this paper, we address this question through a detailed study of user interactions in the Facebook social network. We propose the use of interaction graphs to impart meaning to online social links by quantifying user interactions. We analyze interaction graphs derived from Facebook user traces and show that they exhibit significantly lower levels of the "small-world" properties shown in their social graph counterparts. This means that these graphs have fewer "supernodes" with extremely high degree, and overall network diameter increases significantly as a result. To quantify the impact of our observations, we use both types of graphs to validate two well-known social-based applications (RE and SybilGuard). The results reveal new insights into both systems, and confirm our hypothesis that studies of social applications should use real indicators of user interactions in lieu of social graphs.
Influence of Habitat, Season, and Attractant on Adult Behavior of the Screwworm (Diptera: Calliphoridae) in a Tropical Dry Zone in Costa Rica

Influence of attractant, season, habitat, temperature, and physiological state of the screwworm, Cochliomyia hominivorax (Coquerel), on daily activity and oviposition were examined during a 122 d study in a tropical dry forest in Costa Rica. Flies were marked and released. Numbers of flies visiting baits increased during the wet season and decreased during the dry season; 3 times more flies were observed at baits during the wet season than were observed during the dry season. An average of 33 females and 3 males was observed per day during the study. More flies (3.6 times) were attracted to liver than to sentinel sheep; many flies originally marked at liver failed to return and few of them oviposited on sentinel sheep. Females marked at sheep were recaptured more times and remained in the study area longer. More females marked at sheep sites were recaptured (51.4-54.1%) than those marked at liver sites (32.3-44.7). More than 6 times as many flies were observed at forest than at pasture sites. The physiological state of the female influenced daily activity. High temperatures during midday (> 31 degrees C) depressed activity and decreased the number of foraging hours available for flies during the dry season. Decreasing host resources and number of hours available for foraging may be factors that limit screwworm populations in the dry season.
Age-related decline in executive function predicts better advice-giving in uncomfortable social contexts

Abstract Conventional wisdom suggests that older adults are more likely than young adults to speak their mind. Age-related executive function (EF) decline is believed to underlie this tendency by weakening older adults' capacity to inhibit responses. While age-related EF decline disrupts social and cognitive functioning in many domains, such degeneration may also carry the unforeseen benefit of improving communication in uncomfortable social contexts. We examined the performance of relatively low and high EF older adults and young adults on the socially distressing task of providing critical advice to a troubled obese teenager. Relative to higher EF older adults and younger adults, lower EF older adults were more open, provided more advice, and were seen as more empathic. Moreover, doctors specializing in obesity treatment rated lower EF older adults’ advice to the teen as having greater potential for prompting a lifestyle change. Our findings suggest a potential silver lining to age-related cognitive decline.
A review of adversity, the amygdala and the hippocampus: a consideration of developmental timing.

A review of the human developmental neuroimaging literature that investigates outcomes following exposure to psychosocial adversity is presented with a focus on two subcortical structures – the hippocampus and the amygdala. Throughout this review, we discuss how a consideration of developmental timing of adverse experiences and age at measurement might provide insight into the seemingly discrepant findings across studies. We use findings from animal studies to suggest some mechanisms through which timing of experiences may result in differences across time and studies. The literature suggests that early life may be a time of heightened susceptibility to environmental stressors, but that expression of these effects will vary by age at measurement.
An Approach To Coordinated Uncertainty Management In Automatic Target Recognition

The Automatic Target Recognition (ATIR) problem generally involves the acquisition, digitization and processing of video/IR signals from a given scene, in which the "targets" of interest are to be identified. There has been, up to date, no single effective procedure to handle a wide class of targets acquired by different sensors under different conditions. There has been, however, increasing success in decision making under uncertainty, using a rule based approach. In this paper, the need to appropriately model the types of uncertainties inherent in the decision process, and the need to compensate for disparate evidence sources is emphasized. Along with this, a systematic approach towards uncertainty management within the ATR problem domain is presented.
Activation of p38 mitogen-activated protein kinase (p38 MAPK), extracellular signal-regulated kinase (ERK) and c-jun N-terminal kinase (JNK) during hypoxia in cerebral cortical nuclei of guinea pig fetus at term: role of nitric oxide.

Abstract Previously we have shown that cerebral tissue hypoxia results in generation of nitric oxide (NO) free radicals as well as increased expression of mitogen-activated protein kinase like extracellular signal-regulated kinase (ERK) and c-jun N-terminal kinase (JNK). The present study tested the hypothesis that administration of l -nitro- l -arginine methyl ester ( l -NAME), a NOS inhibitor, prior to hypoxia prevents the hypoxia-induced activation of p38 mitogen-activated protein kinase (p38 MAPK), extracellular signal-regulated kinase (ERK) and c-jun N-terminal kinase (JNK) and in the cerebral cortex of the term guinea pig fetus. To test this hypothesis normoxic (Nx, n = 6), hypoxic (Hx, n = 7) and hypoxic pretreated with l -NAME (Hx + l -NAME, n = 6) guinea pig fetuses at 60 days gestation were studied to determine the phosphorylated p38, ERK and JNK. Hypoxia was induced by exposing pregnant guinea pigs to FiO2 of 0.07 for 1 h. l -NAME (30 mg/kg i.p.) was administered to pregnant mothers 60 min prior to hypoxia. Cerebral tissue hypoxia was documented biochemically by determining the tissue levels of ATP and phosphocreatine (PCr). Neuronal nuclei were isolated, purified and proteins separated using 12% SDS-PAGE, and then probed with specific phosphorylated ERK, JNK and p38 antibodies. Protein bands were detected by enhanced chemiluminescence, analyzed by imaging densitometry and expressed as absorbance (OD × mm2). The relative level of p-p38 was 51.41 ± 9.80 (Nx), 173.67 ± 3.63 (Hx), 58.56 ± 3.40 (Hx + l -NAME), p l -NAME), p l -NAME), p l -NAME prior to hypoxia decreased the relative level of phosphorylated p38, ERK and JNK at term gestation. Since a NOS inhibitor prevented the hypoxia-induced phosphorylation of p38, ERK and JNK, we conclude that the hypoxia-induced activation of p38, ERK and JNK in the cerebral cortical nuclei of guinea pig fetus at term is NO-mediated. We speculate that NO-mediated modification of cysteine residue leading to inhibition of MAP kinase phosphatases results in increased activation of p38, ERK and JNK in the guinea pig fetus at term.
Fluorescent probe studies of normal, persistently infected, Rous sarcoma virus-transformed, and trypsinized rat cells.

Abstract The fluorescent probes pyrene, pyrene butyric acid and N-phenyl 1-naphthylamine were used to study membranes of normal cells, RSV-transformed cells, cells treated with a proteolytic enzyme, and cells persistently infected with lymphocytic choriomeningitis virus. The lifetimes of excited pyrene and pyrene butyric acid showed only minor changes when these probes were in normal, transformed, trypsinized or persistently infected cells. However, pyrene, but not pyrene butyric acid, lifetimes are shorter in cell membranes than in homogeneous solvents. The quenching of excited pyrene in cells by quencher molecules was slower than corresponding reactions in homogeneous solutions indicating that the probe was screened from the quenchers by the membrane. However, quenching reactions with the pyrene butyric acid probe were similar in cells and homogeneous solvents. This indicates that pyrene and pyrene butyric acid reside in different lipid regions of the membrane. Transformed and trypsinized cells showed increased membrane fluidity compared to normal and persistently infected cells. Membrane fluidity was determined from the excimer/monomer fluorescence ratios of pyrene, and by the polarization of N-phenyl 1-naphthylamine fluorescence. Several techniques distinguished between normal and transformed or trypsinized cells; however, the only parameter unique to viral transformation was a blue shift of the fluorescence maxima of N-phenyl 1-naphthylamine. This shift reflected a less polar environment for N-phenyl 1-naphthylamine in virus-transformed cells.
Sudden Death Late After Doxorubicin Administration: Use of Electrophysiological Study and Treatment by Automatic Implantable Cardioverter Defibrillator

Two patients who survived cardiac arrest late after doxorubicin administration are described. Both patients had nonischemic, dilated cardiomyopathies and underwent electrophysiological studies during which no ventricular arrhythmias were induced. Their negative electrophysiological studies despite well documented cardiac arrests and subsequent clinical courses suggest that patients with cardiomyopathies after doxorubicin administra tion and dilated cardiomyopathies of other etiologies have similar natural histories. Treatment with an automatic implantable cardioverter defibrillator appears to be a reasonable therapeutic option for patients with anthracyline associated cardiac disease who have survived their malignancy but at the price of developing life-threatening arrhythmias.