cssi/SciSciGPT-SciSciNet huggingface dataset:
58 Percent Secure: Why Do So Many Wireless Networks Not Use Encryption?

This research project will analyze a large (n=98,000) dataset of wireless access points in two medium-sized US cities to examine changes in the use of encryption in 802.11 wireless networks over time. Further, changes in the use of encryption in these networks based on the socio-economic status of the network owner, and based on whether the owner is a business or an individual will be investigated. There is currently almost no research investigating the spread of wireless encryption as wireless networks become more prevalent. This ground-breaking research will establish a baseline for business and personal use of encryption in wireless networks, correlated with socioeconomic status and other census data. This baseline will help future researchers determine whether changes to wireless protocols and changes in methods of setting up wireless equipment increases the use of security protocols, thereby increasing the security of the network.
1H and 119Sn magnetic resonance study of the SnIV protoporphyrin IX complex of equine myoglobin. Structure of the porphyrin-binding pocket.

Tin protoporphyrin IX (SnPP) is being used in the treatment of hyperbilirubinemia. We have studied the SnPP complex with equine myoglobin (EqMb) by 1H and 119Sn nuclear magnetic resonance spectroscopy (NMR) as a general model for SnPP interaction with hemoproteins. The complex formed from SnPP and EqMb, SnPP.EqMb, was found to have essentially the same porphyrin-binding pocket as EqMbCO, including the same porphyrin orientation in the major form of EqMbCO. 119Sn NMR spectroscopy has been used to demonstrate that the proximal His93F8-metal coordination is likely to be intact in SnPP.EqMb. Minor shifts in the side chain positions of some of the residues are indicated, possibly reflecting the presence of water in the sixth coordination site. SnPP.EqMb appears to be stable; it persists at room temperature for weeks and exhibits very slow exchange rates (2H for 1H) for a large number of amide protons in the pH range 7-9.
Childhood Obesity and Blood Pressure Regulation

Childhood obesity is the most common nutritional problem in children from both developed and non-developed countries. From the 1960s to 1990s, the prevalence of obesity in children grew from 5 to 11% (1). In adults, obesity is recognized as an independent risk factor for the development of both hypertension and cardiovascular disease. In childhood there are data to demonstrate a strong relationship between childhood obesity and hypertension, type 2 diabetes mellitus, dyslipidemia, obstructive sleep apnea, left ventricular hypertrophy, and orthopedic problems. This chapter will summarize (1) the epidemiologic evidence that substantiates obesity as an independent risk factor for the development of hypertension in both adults and children; (2) an explanation of how obesity may cause hypertension; (3) a brief summary of other cardiovascular abnormalities associated with obesity; and (4) a brief summary of how to manage the hypertensive obese child.
Herniated Intervertebral Disc

One of the most significant impacts of magnetic resonance imaging (MRI) has been its ability to exquisitely depict normal and pathologic anatomy of the spine. This unit presents a basic protocol for conventional fast spin echo imaging of the spine. An alternate protocol is presented for gradient recalled echo acquisitions that may be used in the sagittal and/or transverse planes to clearly distinguish between discs and soft tissue and to clarify the spinal neural foramen in the cervical region. A second alternate protocol is presented for contrast enhanced MRI acquisitions.
Insignificant solar‐terrestrial triggering of earthquakes

[1] We examine the claim that solar-terrestrial interaction, as measured by sunspots, solar wind velocity, and geomagnetic activity, might play a role in triggering earthquakes. We count the number of earthquakes having magnitudes that exceed chosen thresholds in calendar years, months, and days, and we order these counts by the corresponding rank of annual, monthly, and daily averages of the solar-terrestrial variables. We measure the statistical significance of the difference between the earthquake-number distributions below and above the median of the solar-terrestrial averages by χ2 and Student's t tests. Across a range of earthquake magnitude thresholds, we find no consistent and statistically significant distributional differences. We also introduce time lags between the solar-terrestrial variables and the number of earthquakes, but again no statistically significant distributional difference is found. We cannot reject the null hypothesis of no solar-terrestrial triggering of earthquakes.
A Comparative Analysis of the Relative Effectiveness of Four Dynamic Lot-Sizing Techniques on Return on Investment

The relative performance of dynamic lot-sizing techniques has been of considerable interest to researchers in recent years. While research has addressed performance in terms of cost-effectiveness, researchers have not determined the impact of dynamic lot-sizing techniques on return on investment (ROI) as it applies to finished goods' schedules. The purpose of this research is to explore the relative performance of four dynamic lot-sizing techniques with regard to ROI, namely the Wagner-Whitin, Incremental Part Period, Silver-Meal, and Groff techniques. Computer graphics are employed to analyze the relative ROI effectiveness.
Trapped gas saturations in carbonate formations

Trapped gas saturations existing after gas displacement by wetting phase imbibition are presented for selected carbonate reservoirs. Formations representing various rock types were investigated, and samples covering the porosity and permeability range within each field were tested. Cores from Smackover reservoirs located within 4 states were included to examine differences in trapped gas which might occur within a carbonate deposited over a large geographical area. The trapped gas varied with initial gas in place and with rock type. With gas in place of 80% of pore space, trapped gas values ranged from a low of 23% of pore space in Type II chalk to a maximum of 69% in the Type I limestone evaluated. Correlation of trapped gas saturation values was attempted using several approaches, but none was entirely satisfactory. No relationship with permeability was found within most reservoirs, or between different reservoirs. Within a given field, trapped gas at a common initial gas saturation typically increased as porosity decreased.
Electrostatics in periodic boundary conditions and real-space corrections

We address periodic-image errors arising from the use of periodic boundary conditions to describe systems that do not exhibit full three-dimensional periodicity. The difference between the periodic potential, as straightforwardly obtained from a Fourier transform, and the potential satisfying any other boundary conditions can be characterized analytically. In light of this observation, we present an efficient real-space method to correct periodic-image errors, based on a multigrid solver for the potential difference, and demonstrate that excellent convergence of the energy with respect to cell size can be achieved in practical calculations. Additionally, we derive rapidly convergent expansions for determining the Madelung constants of point-charge assemblies in one, two, and three dimensions.
Radiation balance and evaporation partitioning in a narrow-row soybean canopy

Seeding rate and row spacing of agricultural crops are managed to maximize yield but also have significant implications for energy partitioning and canopy microclimate. The objective of this study was to measure radiation budget components in a narrowrow soybean [Glycine max (L.) Merr.] canopy, determine soil water evaporation (E) as the difference between measured evapotranspiration (ET) and plant transpiration (T), and compare measured E and T with estimates from an energy balance approach. The study was completed in a production soybean field near Ames, IA, with 350,000 plants ha � 1 in 0.38 m wide rows. The field was planted on 8 May 2004 and continuous measurements were made from 8 June to 27 September. Shortwave and longwave radiation components were measured above the canopy with hemispherical radiometers. Net all-wave and incoming and reflected shortwave radiation were measured beneath the canopy with line radiometers and downwelling longwave radiation was calculated from a radiation balance. ET was measured with an eddy covariance system and T was measured with sapflow stem gauges. On sunny days under full canopy conditions, nearly 90% of the shortwave and net radiation was attenuated by the canopy with over 80% of the available energy utilized by ET. E accounted for 8‐12% of the ETunder full canopy conditions although these percentages may be overestimates due to evaporation of dew present on the canopy. With such a large proportion of the available energy consumed by ET, fluxes of sensible heat (H) were very low and vertical temperature gradients across the soil‐canopy‐ atmosphere interface were only 2‐3 8C. A Priestley‐Taylor energy balance approach used to estimate E and T tended to underestimate E and overestimate T. The E underestimate may be due in part to E including evaporation of dew. Conversely, Twas overestimated by 25 and 14% on sunnydays under full canopy conditions even with direct measurement of Rn interception by the canopy. Use of shortwave extinction coefficients to estimate Rn interception failed to improve T estimates significantly. The high-population, narrow-row planting strategy resulted in a dense canopy that, under full canopy conditions, resulted in very little light penetration or E. Published by Elsevier B.V.
On measuring genetic distance by selection intensity

Summary A simple selection model (fitness 1, w, w2 for AA, Aa, aa) is employed to change the gene fre- quency of one population to another. The genetic distance is then defined as d = -log w between the two populations. The distance is symmetrical with respect to the two populations. It is additive: d, = dI2+d23. The sampling variance of d takes a very simple form. The possible difficulties of using genetic distance in studying evolutionary history have been briefly discussed. The writer means no offence to those who have developed or used the various measures of genetic distance.
Isolated weakness of the orbicularis oculi muscle from myasthenia gravis

Myasthenia gravis often produces weakness of the orbicularis oculi, levator palpebral and extraocular muscles. Unilateral and isolated involvement of the orbicularis oculi muscle, with sparing of t...
Troubled Diversities, Multiple Identities and the Relevance of Royce: What makes a community worth caring about?

This article raises questions about what it means to be a diverse academic community and about why such diversity is worth struggling to achieve. The controversial arguments of Walter Benn Michaels are critically examined as a stimulus and prelude to considering the more constructive perspectives supplied by Amartya Sen and Josiah Royce. Royce's early 20th century philosophical writings, in particular, are evaluated as resources for thinking about the ideal nature of a college or university community in the 21st century.
First Report of the Pale Cyst Nematode, Globodera pallida, in the United States.

In 2006, a cyst nematode was discovered in tare dirt at a potato (Solanum tuberosum) processing facility in eastern Idaho. The nematode was found during a routine survey conducted jointly by the Idaho State Department of Agriculture and the USDA Animal and Plant Health Inspection Service through the Cooperative Agricultural Pest Survey program. Extensive additional sampling from two suspect fields led to the identification of the same nematode in a 45-acre (18.2-ha) field located in northern Bingham County. The morphology of cysts and second-stage juveniles and molecular analyses established the identity of the species as the pale cyst nematode Globodera pallida (Stone 1973) Behrens 1975. Morphological characters used for identification included cyst shape, characteristics of cyst terminal cone including nature of fenestration, cyst wall pattern, anal-vulval distance, number of cuticular ridges between anus and vulva, and Granek's ratio (1,4). The second-stage juvenile morphologies critical for identifica...
Contact between a smooth microsphere and an anisotropic rough surface

This article discusses the effects of asperities on elastic and adhesive contact between a smooth sphere and a rough surface. Two numerical methods are introduced: an asperity-superposition method and a direct-simulation method. In the first method, geometric parameters such as asperity heights, orientations, and radii of curvature are identified by a least-squares regression of neighboring surface heights measured using an atomic force microscope. The rough surface is reconstructed by the superposition of these asperities. The modeling of adhesive and elastic contacts begins with the modeling of a single parabolic-shaped asperity contact. A generalized JKR model for an arbitrary parabola is developed to suit this purpose. The contact between the rough surface (represented by the supposition of parabolic-shaped asperities) and the sphere consequently is modeled bythe mapping and integration of individual asperity contacts. In the second method, pure-elastic contact is modeled by half-space elastic theory....
Estradiol attenuates the K+-induced increase in extracellular GABA in rat striatum

KEY WORDS 17b-estradiol; GABA; striatum; microdialysis; dopamine (DA); estrogen ABSTRACT Estradiol acts rapidly and directly to inhibit L-type Ca 2þ current in medium spiny neurons from striatum. Since medium spiny neurons contain g-amino- butyric acid (GABA), we hypothesized that estradiol inhibition of Ca 2þ channel cur- rent in the cell body would result in decreased GABA release. In this study, we exam- ined the effect of estradiol on the concentration of GABA, taurine, and glutamate in dialysate from striatum. In support of our hypothesis, the K + -evoked increase in GABA, but not taurine or glutamate, was significantly attenuated 30 min after treat- ment with estradiol. Synapse 59: 122-124, 2006. V C 2005 Wiley-Liss, Inc.
Principal Stress Directions from Plastic Flow in Crystals

Methods for determining orientations of principal stress axes in deformed rocks involve dynamic analysis of twin-gliding and of extinction bands produced by inhomogeneous translation gliding in crystals. The methods, beginning with Turner9s (1953) technique for dynamic analysis of calcite twins, have been developed using as guides the results from experiments under controlled laboratory conditions. Structures induced by intragranular flow in calcite, dolomite, quartz, micas, orthopyroxenes, clinopyroxenes, olivine, and other common rock-forming materials, may now be used to derive orientations of principal stresses causing the deformation. The various methods, some new, are discussed in detail and examples of their application to tectonites are given. The usefulness of such studies is illustrated by evaluating the observed orientations of principal stresses around folds in light of new data from a theoretical analysis of large amplitude folding of viscous layers in a less viscous matrix. Other areas of research in structural geology in which these methods should prove useful have also been outlined.
Monte Carlo studies of x-ray scattering in transmission diagnostic radiology.

Monte Carlo methods have been used to simulate the scattering of x rays in polystyrene and water phantoms. In particular, the ratio of the scattered to total x‐ray fluence (scatter fraction) has been calculated for monoenergetic x‐ray beams in the energy region relevant to diagnostic radiology and nuclear medicine (30–660 keV). Simulations have been made for representative values of the pertinent geometrical factors; phantom thickness from 5 to 21 cm, x‐ray beam diameters of 10 and 25 cm, and scatterer‐to‐image‐plane separations from 0 to 20 cm. As a function of x‐ray energy, the scatter fraction was found to vary slowly between 30 and 100 keV, and to decrease between 100 and 660 keV. The present results were generated with a special transport code which included the effects of special geometries and the response of the x‐ray detector. With the inclusion of these effects, the results resolved inconsistencies and showed good agreement with previous measured and calculated data.
Conducting Meta-Analysis Using the Proc Means Procedure in Sas

The methodology for using the PROC MEANS procedure in SAS to perform the data computations called for by the Hunter and Schmidt approach to meta-analysis is presented. Using SAS for meta-analytic data analysis offers several potential advantages including ease of use, flexibility, and widespread availability. Specific procedures are presented for calculating summary statistics and then correcting these summary statistics for sampling error and other statistical artifacts such as range restriction and measurement error. One particularly attractive feature of this approach is the ease with which potential moderator variables can be analyzed simply by adding a few additional statements to the SAS program.
Atrial natriuretic peptides increase calcitonin gene-related peptide within human circulation.

Long-acting natriuretic peptide (LANP), vessel dilator, and atrial natriuretic factor (ANF) (each infused at 100 ng/kg body weight [BW] · min for 60 minutes) increased the circulating concentration of calcitonin gene—related peptide (CGRP) threefold to fourfold in 30 healthy humans. Within 30 minutes of stopping ANF infusion, the CGRP circulating concentration had returned to preinfusion levels, whereas its increase secondary to the other atrial peptides was still significant 2 to 3 hours after cessation of their infusions. There was a 50% decreased excretion (P < .001) of CGRP into the urine secondary to LANP and vessel dilator, which correlated with the increase of CGRP in the circulation. The ANF-induced 50% decreased CGRP excretion occurred after the circulating concentration of CGRP had returned top preinfusion levels. Kaliuretic peptide did not affect CGRP breakdown of CGRP as part of their mechanism of increasing CGRP in plasma, whereas the ANF effect of increasing CGRP in plasma appears to be secondary to stimulating the release of CGRP.
Mineral analysis provides insights into the mechanism of biomineralization.

ThismarkstheﬁrstofanewseriesofspecialissuesofCalciﬁedTissueInternational, planned by the EditorialBoard, which will present original articles on a partic-ulartopicorareaofresearchwithinthejournal’sscope.TopicswillbeidentiﬁedbytheEditorsandtheEditorialBoard. This inaugural issue focuses on techniques ofmineral analysis and how they help us understandmechanismsofbiomineralization.Thethemewasstim-ulated by discussions at the recent 7th InternationalConference on the Chemistry and Biology of Mineral-ized Tissues (ICCBMT) [1]. Contributions to this ﬁrstspecialissuecomefrominvitedauthorsidentiﬁedamongparticipants at the ICCBMT meeting and scientistsworkinginspeciﬁc areas relevanttobiomineralization.Some were selected from papers dealing with germanetopics already submitted to Calciﬁed Tissue Interna-tional.Inthisselectionprocess,emphasiswasplacedonyounginvestigatorswhointhefutureshallhaveamajorimpact on the calciﬁed tissues ﬁeld. All the articlespublished in this issue describe original work and un-derwentfullpeerreviewtoensurethenecessaryscientiﬁcrigor that is required for publication in a high-qualityjournal.Thisapproachwaspreferredtothemoreusualreviewformat,primarilybecauseifwasfeltthatdirect,hands-onexamplesofhowsuchmethodologiescouldbeapplied to address actual scientiﬁc questions wouldprovideamorepoignantandlivelypresentationofthesecomplex and somewhat ‘‘esoteric’’ techniques, as com-pared to a dry description. It is our hope that evenreadersnotwellversedinthestructureandanalysisofthe mineral phase would be able to at least considerthesepowerfultechnologiesintheirfutureexperimentaldesigns,whenmineralizationisinvolved.Byunderstandingthestructureofmineralasitformsandmatures,onecanobtainnewinsightsintothefac-torscontrollingtheseprocesses.Thisjournaloftenfea-turesarticlesthatincludetheapplicationofoneormoreof these techniques, and the Editorial Board believesthatCalciﬁedTissueInternationalisaveryappropriatevehicle for publication of research in the biomineral-izationﬁeld.Thegamutoftechniquesthatarediscussedand applied in the following articles is necessarily in-complete because of space and time limitations. How-ever,itishopedthatthroughthisissuewecanhighlightamajorityofthetechniquescurrentlyavailable.Someofthe methods have existed for more than one hundredyears,andsomearenewandinnovative.Someprovidevast insight into mineralization mechanisms; some aremorelimited.Asamajorcaseinpoint,thehistochem-icaltechniquescurrentlyinusetoidentifythepresenceofmineralincellculturearehighlysuspect,aspointedoutintheopeningarticlebyBonewaldandcoworkers,who demonstrate that von Kossa positive osteoblastculturesdonotnecessarilycontainmineraldetectablebyphysicochemicalmethods.Othernewertechniquesneedto be compared to existing methods as they evolve, asexempliﬁedbytheworkofTongetal.
Sustained propagation of ultra-lean methane/air flames with pulsed microwave energy deposition

Abstract An investigation of pulsed microwave energy addition to laminar methane/air flame fronts is undertaken. Microwave coupling efficiencies of up to 60% are measured in a microwave resonator with very low average power requirements (
Small‐Angle Neutron Scattering and Contrast Variation Measurement of the Interfacial Surface Area in PBX 9501 as a Function of Pressing Intensity

Small-angle neutron scattering with contrast variation was used to measure the interfacial surface area in a composite high explosive formulated with a deuterated binder. Continuing our work on the effect of varying the pressing intensity on void and binder size distribution, the effect of pressing intensity on the three interfaces (HMX-binder, HMX-voids and binder-voids) of the PBX 9501 microstructure was studied. Formulation of PBX 9501 with a deuterated binder allowed the neutron scattering length density contrast to be varied and thus allowed differentiation of the three interfaces. Porod analysis was used to measure the surface area. The surface area at the interfaces of HMX and binder was found to increase with increasing pressing intensity, while the surface area between HMX and voids may have decreased slightly. No evidence was found for voids within the binder at any pressing intensity.
Increase in Expression Levels and Resistance to Sulfhydryl Oxidation of Peroxiredoxin Isoforms in Amyloid β-Resistant Nerve Cells

Peroxiredoxins (Prxs) are a ubiquitously expressed family of thiol peroxidases that reduce hydrogen peroxide, peroxynitrite, and hydroperoxides using a highly conserved cysteine. There is substantial evidence that oxidative stress elicited by amyloid β (Aβ) accumulation is a causative factor in the pathogenesis of Alzheimer disease (AD). Here we show that Aβ-resistant PC12 cell lines exhibit increased expression of multiple Prx isoforms with reduced cysteine oxidation. Aβ-resistant PC12 cells also display higher levels of thioredoxin and thioredoxin reductase, two enzymes critical for maintaining Prx activity. PC12 cells and rat primary hippocampal neurons transfected with wild type Prx1 exhibit increased Aβ resistance, whereas mutant Prx1, lacking a catalytic cysteine, confers no protection. Using an antibody that specifically recognizes sulfinylated and sulfonylated Prxs, it is demonstrated that primary rat cortical nerve cells exposed to Aβ display a time-dependent increase in cysteine oxidation of the catalytic site of Prxs that can be blocked by the addition of the thiol-antioxidant N-acetylcysteine. In support of previous findings, expression of Prx1 is higher in post-mortem human AD cortex tissues than in age-matched controls. In addition, two-dimensional gel electrophoresis and mass spectrometry analysis revealed that Prx2 exists in a more oxidized state in AD brains than in control brains. These findings suggest that increased Prx expression and resistance to sulfhydryl oxidation in Aβ-resistant nerve cells is a compensatory response to the oxidative stress initiated by chronic pro-oxidant Aβ exposure.
No additional metal particle formation using the needle-through-needle combined epidural/spinal technique.

Background. Combined epidural/spinal analgesia utilizing a needle-through-needle technique has become very popular in anesthesia. However, findings of concave deformities at the orifice of Tuohy needles after spinal needle passage have raised concerns that metal fragments might be deposited within the epidural space. This study was proposed to investigate whether the needle-through-needle technique does produce metallic flecks. Methods. Ten unused Tuohy and Hustead epidural needles were inspected microscopically and photomicrographed prior to flushing saline through each into a single tissue culture well. After drying, a single pass was made with a 120 mm 24-gauge Sprotte needle through each epidural needle to maximal extension while the orifice was within another tissue culture well. Each needle was again flushed into a third well before reexamination and photomicroscopy. Each of the wells was inspected for metallic particles by microscopy. Additional freshly unpackaged Tuohy needles were microscopically examined after exposure to a magnetic field. Results. Comparison of micrographs before and after needle experiments revealed concave deformities at the orifice of all the Tuohy and Hustead needles. No particles were observed in either of the two saline-flushed wells or within the well in which the needle-through-needle passes were made. Inspection of unused Tuohy needles exposed to a magnetic field revealed metal filings “standing up” along the bevel of every needle examined. Conclusions. Metallic particles are not produced by the needle-through-needle technique. However, metal particles are an apparent contaminant of all epidural needles and are probably routinely introduced into patients when the needle is placed.
Control for social desirability in the trait evaluation index.

Summary The Trait Evaluation Index supposedly controls for social desirability of the alternatives in each triad by using forced-choice methodology. This claim was tested using 63 Ss asked to select the most desirable alternative in each triad. With a significant Chi-Square for an item interpreted as lack of control for desirability, 77% of the items yielded significant Chi-Squares.
Expression of functional cell-cell channels from cloned rat liver gap junction complementary DNA

An oocyte expression system was used to test the relation between a complementary DNA (cDNA) clone encoding the liver gap junction protein and cell-cell channels. Total liver polyadenylated messenger RNA injected into oocytes induced cell-cell channels between paired oocytes. This induction was blocked by simultaneous injection of antisense RNA transcribed from the gap junction cDNA. Messenger RNA selected by hybridization to the cDNA clone and translated in oocyte pairs yielded a higher junctional conductance than unselected liver messenger RNA. Cell-cell channels between oocytes were also formed when the cloned cDNA was expressed under the control of a heat-shock promoter. A concentration-dependent induction of channels was observed in response to injection with in vitro transcribed gap junction messenger RNA. Thus, the liver gap junction cDNA encodes a protein that is essential for the formation of functional cell-cell channels.
Simplified approach to study fuel rod rupture risks by bending or Euler buckling

TN International and International Nuclear Services started commonly in early 2000s the Fuel Integrity Project (FIP) to develop a methodology to assess the response of fresh and used light water reactor (LWR) fuel assemblies (F/A) during 9 m regulatory drops. The analysis of experimental knowledge acquired from fresh F/A behaviour during drop tests and various mechanical tests on fresh and used fuel rod (F/R) samples has led to the elaboration of FIP methodology, allowing the assessment of F/A damage during lateral and axial accident drops of a packaging. In particular, the developed pessimistic mechanical evaluations based on comparison with results of reference bending tests permit to assess, using elastic beam formulas, F/R rupture risks in intergrid bending or Euler buckling configurations. These simple, but interesting, static mechanical approaches can be used for several possible loadings and boundary conditions. They take into account the following: the F/R maximum possible deflection in cask lodge...
Peptide YY levels are decreased by fasting and elevated following caloric intake but are not regulated by leptin.

Aims/hypothesis Peptide YY (PYY) is a gut-derived hormone that has been shown to reduce short-term food intake in animals and humans. It has been proposed that deficiency of PYY contributes to obesity in humans. However, the physiology of PYY regulation by factors such as caloric restriction, or by other molecules important in energy homeostasis, e.g. leptin, remains to be fully elucidated.
Potassium transport in Chlamydomonas reinhardtii: isolation and characterization of transport-deficient mutant strains.

Putative potassium-transport-deficient mutant strains of Chlamydomonas reinhardtii Dang. were induced by ultra-violet mutagenesis and were identified by their dependence on abnormally high concentrations of potassium for growth. Potassium transport studies employing 86Rb as a tracer were carried out with wild-type cells and with three independently isolated KDP (potassium-dependent phenotype) clones. Wildtype cells exhibit two transport activities. Transport activity A was expressed when cells were grown in medium supplemented with 10 mM KCl. The transporter with type-A activity does not discriminate between either Rb+ or K+ as a substrate and has a Km for Rb+ equal to 1 mM and a Vmax equal to 31 nmol Rb+ h-1 10-6 cells. Transport activity B was expressed when cells were starved of potassium for 24 h. The transporter with type-B activity prefers K+ to Rb+ as a substrate; it has a Km for Rb+ equal to 2.5 mM and a Vmax equal to 210 nmol Rb+ h-1 10-6 cells. All three mutant clones exhibit transport activity comparable to type-A when grown in 10 mM KCl. When starved of potassium for 24 h, two KDP clones demonstrate no transport activity and the third clone continues to exhibit only type-A activity.
Carbon-nitrogen bond formation from the reaction of ammonia with dicarbon on the Pt(111) surface

The reaction of NH3 with C2 molecules on a Pt(111) surface was investigated using temperature programmed desorption, X-ray photoelectron spectroscopy (XPS), and reflection absorption infrared spectroscopy. Surface C2, which was prepared by dissociative adsorption of acetylene (C2H2) at 750 K, reacts with NH3 to form C−N bonds as revealed by the desorption of HCN and C2N2 at 570 and 650 K, respectively. The formation of C−N bonds was also detected with XPS when the NH3/C2 layer was annealed from 85 to 200 K through the appearance of a chemically shifted C 1s peak at 286.5 eV, which is well-resolved from the unreacted C 1s peak at 284.3 eV. Comparison of calculated and experimental RAIRS data indicates that C−N bond formation involves an HCCNH2 surface intermediate.
On singular perturbations due to fast actuators in hybrid control systems

A stability result is given for hybrid control systems singularly perturbed by fast but continuous actuators. If a hybrid control system has a compact set globally asymptotically stable when the actuator dynamics are omitted, or equivalently, are infinitely fast, then the same compact set is semiglobally practically asymptotically stable in the finite speed of the actuator dynamics. This result, which generalizes classical results for differential equations, justifies using a simplified plant model that ignores fast but continuous actuator dynamics, even when using a hybrid feedback control algorithm.
Isomorphism criterion for monomial graphs

Let q be a prime power, Fq be the field of q elements, and k, m be positive integers. A bipartite graph G = Gq(k, m) is defined as follows. The vertex set of G is a union of two copies P and L of two-dimensional vector spaces over Fq, with two vertices (p1, p2) ∈ P and [ l1, l2] ∈ L being adjacent if and only if p2 + l2 = p 1k l 1m . We prove that graphs Gq(k, m) and Gq′(k′, m′) are isomorphic if and only if q = q′ and lgcd (k, q - 1), gcd (m, q - 1)r = lgcd (k′, q - 1),gcd (m′, q - 1)r as multisets. The proof is based on counting the number of complete bipartite INFgraphs in the graphs. © 2005 Wiley Periodicals, Inc. J Graph Theory 48: 322–328, 2005
Computerized detection of Low SNR cases in NSECT: An ROC-based sensitivity analysis

Neutron stimulated emission computed tomography (NSECT) is an imaging technique that uses gamma energy spectra emitted from inelastic scattering of fast neutrons to extract quantitative elemental information from tissue. The NSECT acquisition system consists of a neutron source and one or more gamma detectors. For the NSECT system to be adequately sensitive to low elemental concentrations it is important to accurately extract the relevant gamma counts despite low signal to noise ratio (SNR) conditions. One technique to improve the sensitivity of the system and lower the minimum detectable level is to use computerized post processing of the gamma spectra. In this project, we describe a method of improving the sensitivity of the NSECT system through computerized post processing of the NSECT signal. The signal and noise in NSECT are photon-counting systems and hence are Poisson distributed. Modifying the Gaussian signal known exactly (SKE) case of signal detection theory to incorporate Poisson distributions, a likelihood based optimum detector was designed for each gamma detector in the NSECT acquisition system. This detector was implemented in MATLAB for the simulated iron concentrations and was followed by ROC analysis to study the detection sensitivity of the designed detector. In this project a GEANT4 simulation of a tissue sample with a 2 cm lesion (at a fixed location) was used to generate an NSECT spectrum from a single projection for different iron concentrations in the lesion. The iron concentration values were set to represent clinical liver iron overload. The gamma signal corresponding to iron and the background noise from Compton scattering of high-energy gamma photons were estimated using Poisson distributions. The results showed that for the simulated lesion position, the area under the curve (AUC) increased with increasing iron concentration, and 4 of the 6 gamma detectors were able to detect the lowest simulated iron concentration (1 mg/g). These results demonstrate that NSECT combined with computerized post processing has the potential to detect clinically relevant concentrations of iron to diagnose and quantify liver iron overload.
Localized Pericardial Hematoma Presenting With Acute Hypoxemia

Localized pericardial hematomas after cardiac surgery may have atypical clinical presentations due to regional alterations in cardiac function and hemodynamics. We report a case of extravascular thrombus that compressed the main pulmonary artery and produced acute hypoxemia due to right-to-left shunting across a patent foramen ovale. We review the pathophysiology leading to this finding and the echocardiographic studies that established the diagnosis.
Amelioration by leucovorin of methotrexate developmental toxicity in rabbits

Methotrexate (MTX) is lethal or teratogenic to embryos of all species tested. New Zealand white rabbit embryos are relatively resistant to the embryolethal effects of MTX. However, when pregnant does were injected iv with 19.2 mg MTX/kg on gestational day 12, virtually all surviving fetuses exhibited multiple malformations of the head, limbs, and trunk. MTX is a structural analogue of folic acid that competitively inhibits dihydrofolate reductase, thereby preventing formation of folinic acid and essentially stopping one carbon metabolism. One carbon metabolism is important in the synthesis of methionine, histidine, glycine, and purine bases that are required for the de novo synthesis of DNA. Presumably these metabolic effects of MTX relate directly to its mechanism of developmental toxicity. An ameliorative treatment has been tested utilizing i.v. injection of pregnant rabbits with leucovorin (LV), a close structural analogue of folinic acid (the product of the inhibited enzyme), at various times after MTX exposure. When LV was injected at times up to 24 hours after MTX fewer malformed fetuses resulted and the incidence of specific malformations was reduced. When given at times up to 20 hours after MTX administration, LV virtually eliminated the grossly apparent effects of MTX at term. In the forelimb bud, MTX increased the extracellular space surrounding limb bud mesenchymal cells within 8-10 hours; this process continued through 16 hours and remained unabated by 24 hours. Mesenchymal cell nuclei became hyperchromatic and pyknotic during this time period. By 24 hours, a moderate amount of cellular debris was observed in the mesenchymal compartment of limb buds from approximately one-third of the embryos examined. Endothelial cell nuclei of the limb bud vasculature did not exhibit the histopathological alterations observed in the mesenchymal cells. Limb buds from embryos injected with LV at times up to 6 hours after MTX were histologically normal. When LV treatment was delayed until 16 or 20 hours after MTX, mesenchymal nuclei regained normal appearance within 2 hours of treatment; further, the abnormally large intracellular space began to decrease during the next 4 hours. Cellular debris was not a prominent feature of limb buds from LV-treated embryos examined at any time. Embryos from rabbits injected with LV at 24 hours after MTX exhibited either typical MTX-induced lesions or a sequence of reparative events similar to those described for the 16 and 20 hour LV-treated embryos.(ABSTRACT TRUNCATED AT 400 WORDS)
Neighborhood of residence and incidence of coronary heart disease.

BACKGROUND: Where a person lives is not usually thought of as an independent predictor of his or her health, although physical and social features of places of residence may affect health and health-related behavior. METHODS: Using data from the Atherosclerosis Risk in Communities Study, we examined the relation between characteristics of neighborhoods and the incidence of coronary heart disease. Participants were 45 to 64 years of age at base line and were sampled from four study sites in the United States: Forsyth County, North Carolina; Jackson, Mississippi; the northwestern suburbs of Minneapolis; and Washington County, Maryland. As proxies for neighborhoods, we used block groups containing an average of 1000 people, as defined by the U.S. Census. We constructed a summary score for the socioeconomic environment of each neighborhood that included information about wealth and income, education, and occupation. RESULTS: During a median of 9.1 years of follow-up, 615 coronary events occurred in 13,009 participants. Residents of disadvantaged neighborhoods (those with lower summary scores) had a higher risk of disease than residents of advantaged neighborhoods, even after we controlled for personal income, education, and occupation. Hazard ratios for coronary events in the most disadvantaged group of neighborhoods as compared with the most advantaged group--adjusted for age, study site, and personal socioeconomic indicators--were 1.7 among whites (95 percent confidence interval, 1.3 to 2.3) and 1.4 among blacks (95 percent confidence interval, 0.9 to 2.0). Neighborhood and personal socioeconomic indicators contributed independently to the risk of disease. Hazard ratios for coronary heart disease among low-income persons living in the most disadvantaged neighborhoods, as compared with high-income persons in the most advantaged neighborhoods were 3.1 among whites (95 percent confidence interval, 2.1 to 4.8) and 2.5 among blacks (95 percent confidence interval, 1.4 to 4.5). These associations remained unchanged after adjustment for established risk factors for coronary heart disease. CONCLUSIONS: Even after controlling for personal income, education, and occupation, we found that living in a disadvantaged neighborhood is associated with an increased incidence of coronary heart disease.
Sources of self-esteem and the person X situation controversy.

were found for major sources of self-esteem. Results were discussed in terms of the utility of the self-esteem construct in interactions of persons and situations. A number of recent studies have suggested the importance of self-esteem as a mediator of many types of social behaviors (e.g., Wylie, 1974; Coopersmith, 1967; Rosenberg, 1965; Wilson, Aronoff, & Messk, in press). The results of these srudies indicate that individuals with high self-esteem are assertive, trusting, competent, autonomous, achieving, respected by peers, and generally efficacious in meeting personal goals and aspirations. These characteristics define global self-esteem or attributes commonly shared by persons of high self-esteem. While the global self-esteem construct is useful in the srudy of individual differences, most measures of the construct do not differentiate the specific sources which contribute to self-esteem (Wylie, 1974). Further, Simpson (in press) has recently demonstrated that global, situational and task-specific measures of self-esteem are useful in predicting behavior across and within situations. This finding is particularly important in light of the current person X situation controversy (e.g., Mischel, 1973; Endler, 1973; Alker, 1972) which focuses on the relative importance of situational factors and personality traits as determinants of behavior. Mischel (1973) has argued that personality factors are less significant than situational determinants since behavior varies greatly between situations. On the other hand, Bem and Allen (1974) have shown that more extraverted indiciduals tend to be consistent in their behavior across situations whereas more introverted individuals are highly variable. Moreover, several studies (e.g., Ziller, Long, Hagey, & Smith, 1969; Campus, 1974; Block, 1961; Brownfain, 1952) suggest that individuals with high self-esteem are more consistent in their response modalities across situations than highly anxious individuals with an external locus of control. Thus, the self-esteem construct, whether defined as a cognitive process or as a personality trait, may be the most parsimonious personal variable relevant to the study of interactions of persons and situations. However, Mischel ( 1973) has argued that personality traits such as self-esteem only account for 10% of the variance across situations and that more attention should be centered on understanding the influence of situational factors. Mischel ( 197 3 ) states that individual differences exert the greatest influence in ambiguous situations where situational cues are minimized. Alterna
On the thermodynamic phase diagrams of helium three

Abstract The object of the present paper is an analysis of the thermodynamic consequences resulting from the observed anomaly at the temperature Ta of the melting pressure line P(T) of He3 through the formation of a minimum at this temperature. One is led to prove first the anomalous character of the volume line Vl(T) of the liquid, in equilibrium with the solid, on the basis of data available on the high temperature side of Ta and at Ta. This volume anomaly consists in a maximum of Vl(T) at Ta. The similar anomaly of the solid volume line Vs(T) at Ta will be also to result from the temperature double-valuedness of the isobaric and isochoric states of the liquid and solid along the phase equilibrium lines. The saddle point type character of the states [P(Ta), Vl(Ta)] and [P(Ta), Vs(Ta)], combined with the existence of the locus of vanishing expansion coefficients of the liquid, lead to recognizing the oscillatory character of the isobar of pressure P(Ta) and isochore of volume Vl(Ta) of the liquid. The oscillations result from the vanishing of the second partial temperature derivatives of these isobar and isochore of anomaly at three different temperatures, the temperature Ta being one of these. These changes in sign of the curvature of these phase diagram lines impose the occurrence of probably observable anomalies in the constant pressure and constant volume heat capacities of higher pressure, p ∼ P(Ta), and smaller volume V ∼ V(Ta). The anomalous isobaric lines yield a fairly complete description of the associated expansion coefficients of the liquid. The vanishing expansion coefficient of both the liquid and the solid at the states of anomaly will be shown to result directly from the saddle point type character of these states of the two phases. Various features of the isothermal compressibility of the liquid will be derived, together with its evaluation at isolated states of these two phases in equilibrium from the sole knowledge of the local behavior of the equilibrium lines P(T), Vl(T), and Vh(T). The series of anomalous properties of He3 in a new pressure and temperature range disclosed here appear to warrant their detailed experimental investigations.
Pronounced occurrence of long-chain alkenones and dinosterol in a 25,000-year lipid molecular fossil record from Lake Titicaca, South America

Abstract Our analysis of lipid molecular fossils from a Lake Titicaca (16° S, 69° W) sediment core reveals distinct changes in the ecology of the lake over an ∼25,000-yr period spanning latest Pleistocene to late Holocene time. Previous investigations have shown that over this time period Lake Titicaca was subject to large changes in lake level in response to regional climatic variability. Our results indicate that lake algal populations were greatly affected by the changing physical and chemical conditions in Lake Titicaca. Hydrocarbons are characterized by a combination of odd-numbered, mid- to long-chain (C 21 –C 31 ) normal alkanes and alkenes. During periods when lake level was higher (latest Pleistocene, early Holocene, and late Holocene), the C 21 n -alkane, and the C 25 and C 27 alkenes dominate hydrocarbon distributions and indicate contribution from an algal source, potentially the freshwater alga Botryococcus braunii . The C 30 4 α-methyl sterol (dinosterol) increases sharply during the mid-Holocene, suggesting a greatly increased dinoflagellate presence at that time. Long-chain alkenones (LCAs) become significant during the early Holocene and are highly abundant in mid-Holocene samples. There are relatively few published records of LCA detection in lake sediments but their occurrence is geographically widespread (Antarctica, Asia, Europe, North America). Lake Titicaca represents the first South American lake and the first low-latitude lake in which LCAs have been reported. LCA abundance and distribution may be related to the temperature-dependent response of an unidentified algal precursor. Although the LCA unsaturation indices cannot be used to determine absolute Lake Titicaca temperatures, we suspect that the published LCA U 37 K unsaturation calibrations can be applied to infer relative temperatures for early to mid-Holocene time when LCA concentrations are high. Using these criteria, the U 37 K unsaturation indices suggest relatively warmer temperatures in the mid-Holocene. In contrast to previous speculation, lipid analysis provides little evidence of a greatly increased presence of aquatic plants during the mid-Holocene. Instead, it appears that a few algal species were dominant in the lake. Based on the dramatic rise in abundances of LCAs and dinosterol during the early to mid-Holocene, we suspect that the algal producers of these compounds rose in response to a combination of physical and chemical changes in the lake. These include temperature, salinity, and alkalinity changes that occurred as lake level dropped sharply during a multi-millennial drought affecting the Central Andean Altiplano.