cssi/SciSciGPT-SciSciNet huggingface dataset:
Designing optimal gain profiles for slow-light applications

We present the methodology for designing the optimal gain profiles for slow-light systems under the given system constraints. Optimal system designs for the multiple Lorentzian gain lines make the gain spectrum uniform over larger bandwidth compared to the single-line gain system. The design procedure for the multiple-line gain systems is modified to make the gain spectrum uniform over arbitrarily broad bandwidth and applied to the design of the gain-only and gain+absorption slow-light media. The optimization of the triple-line gain system improves the delay-bandwidth product 1.7 times the delay-bandwidth product for the single-line gain system. For the broadband slow-light system, the optimal gain + absorption design and the optimal gain-only design improve the fractional delay performance by factors of 1.8 and 1.4, respectively, compared to the Gaussian noise pump broadened (GNPB) system.
TmRNA Is Required for Correct Timing of DNA Replication in Caulobacter crescentus

SsrA, or tmRNA, is a small RNA that interacts with selected translating ribosomes to target the nascent polypeptides for degradation. Here we report that SsrA activity is required for normal timing of the G1-to-S transition in Caulobacter crescentus. A deletion of the ssrA gene, or of the gene encoding SmpB, a protein required for SsrA activity, results in a specific delay in the cell cycle during the G1-to-S transition. The ssrA deletion phenotype is not due to accumulation of stalled ribosomes, because the deletion is not complemented by a mutated version of SsrA that releases ribosomes but does not target proteins for degradation. Degradation of the CtrA response regulator normally coincides with initiation of DNA replication, but in strains lacking SsrA activity there is a 40-min delay between the degradation of CtrA and replication initiation. This uncoupling of initiation of replication from CtrA degradation indicates that there is an SsrA-dependent pathway required for correct timing of DNA replication.
Analytical Investigations of Incompressible Turbulent Swirling Flow in Stationary Ducts

Taylor vorticity transport theory and von Karman similarity hypothesis extended to consider three dimensional fluctuating velocity field in analyzing turbulent swirling ducted flow
Field survey and analysis of hillslopes on tower karst in Guilin, southern China

Limestone dissolution in tropical and subtropical humid southern China created residual hills with steep slopes, a landform that is referred to as tower karst. Two types of tower karst landform feature, fenglin or peak forest (isolated towers) and fengcong or peak cluster (linked-base towers), were identified in Guilin. Previous studies proposed two hypotheses regarding their origin and evolution. One is the sequential evolution model from peak cluster to peak forest. The other is a parallel development model, which postulates that both peak cluster and peak forest have developed simultaneously. Through detailed field survey and analysis of slope forms on tower karst in Guilin, it was found that the mean slope angle of the towers is very high (62·4°) and ranges from 60° to 75°. There is no significant difference in mean slope angle and slope angle distribution between towers in the peak cluster basin and peak forest floodplain areas. Mean slope angle increases with intensified fluvial dissection. Three levels of caves in the towers of the peak forest in Guilin were identified in previous research. The isolated towers of the peak forest as well as scattered residuals of peak cluster are generally distributed in the centre of the Guilin syncline. Favourable circumstances of allogenic water concentration indicate that development of the peak forest resulted from the combined effects of subcutaneous and subterranean dissolution as well as subsequent collapse and recession by fluvial erosion after uplifting. By contrast, peak clusters generally occur on the limbs of the syncline or at the periphery of the Guilin basin with relatively higher elevations. The thick vadose zone and predominantly vertical flow suggests that peak clusters are mainly formed by the combination of intensive uplifting and the enhancement of original dolines. The evidence of slope survey and slope analysis suggests that both isolated towers and linked-base towers developed simultaneously but by different mechanisms of formation and different combinations of development processes. Copyright © 2000 John Wiley & Sons, Ltd.
n-Al0.15Ga0.85 N/p-6H–SiC heterostructure and based bipolar transistor

Abstract Heterojunction bipolar transistor (HBTs) based on Al0.15Ga0.85 N/6H–SiC heterojunction was fabricated. Room-temperature current–voltage (I–V) characteristics of n-Al0.15Ga0.85 N/p-6H–SiC emitter–base heterojunction exhibited good rectifying behavior with a forward current 5 × 10−2 A and reverse current 3 × 10−9 A at 10 V and −10 V, respectively. Analysis of the temperature dependent I–V characteristics of this heterojunction revealed a barrier height of 1.1 eV. The fabricated n-Al0.15Ga0.85 N/p-SiC/n-SiC bipolar transistor did not exhibit common-emitter operation, however, common-base operation was observed with current gain β = IC/IB ranging in 75–100.
A Multidimensional Analysis of Criminal Specialization Among Single-Victim and Serial Homicide Offenders:

The degree of difference between single and serial homicide offenders’ criminal histories is not fully understood at present. The current study compares these offenders’ criminal histories to identify general trends in the degree and type of offending specialization that they demonstrate. The results showed that a single framework can account for patterns in the criminal histories of these offenders, according to a co-occurrence of violent versus instrumental offenses, and most offenders could be allocated to one of these offense groups and considered specialists. However, serial offenders were more likely to be considered specialists in instrumental offenses compared to single offenders, highlighting one important point of difference between these offenders.
Evaluating the Oral Examination in Virginia's Licensing of Clinical Social Workers

An oral examination has been used in Virginia's licensing of clinical social workers since 1978 in addition to a written examination. This article presents findings of an evaluation of the oral examination employing a stratified random sample of 99 social workers taking the oral examination from 1978 through 1988. A t test and logistic regression analyses were used to determine if characteristics of the social workers' experience in MSW field instruction, post-MSW employment, or competencies listed by the candidate on the licensing application could predict the outcome of the oral exam. Results of the study indicate that there were no characteristics of the candidates or their practice experiences that predicted the outcome ofpassing or failing the oral examination.
Fast electron correlation methods for molecular clusters without basis set superposition errors.

Two critical extensions to our fast, accurate, and easy-to-implement binary or ternary interaction method for weakly interacting molecular clusters [S. Hirata et al., Mol. Phys. 103, 2255 (2005)] have been proposed, implemented, and applied to water hexamers, hydrogen fluoride chains and rings, and neutral and zwitterionic glycine-water clusters with an excellent initial performance assessment result. Our original method included up to two- or three-body Coulomb, exchange, and correlation energies exactly and higher-order Coulomb energies in the dipole-dipole interaction approximation. In this work, the dipole moments are replaced by atom-centered point charges determined so that they reproduce the electrostatic potentials of the cluster subunits accurately and also self-consistently with one another in the cluster environment. They have been shown to lead to a dramatic improvement in the description of short-range electrostatic potentials not only of large, charge-separated subunits such as zwitterionic ...
PTIDES on flexible task graph: real-time embedded systembuilding from theory to practice

The Flexotask system claims to enable implementation of both real-time applications and real-time schedulers in a Java Virtual Machine using an actors-like model. The PTIDES model is an actors-like model that claims to deliver precise control over end-to-end latencies in a complex real-time system. The present work jointly investigates both claims by (1) implementing several PTIDES-based schedulers as Flexotask scheduler plugins, and (2) using the resulting system to implement a new reactive control program for a simulation of the JAviator. We present results from the realistic JAviator control application and also from synthetic benchmarks designed to shed light on the differences between the several PTIDES schedulers we implemented.
Destination Marketing: Measuring the Effectiveness of Brochures

This article reports the findings of an exploratory study defining effectiveness for assessing impacts of brochures. Using data collected from 2,400 information-inquirers of a destination, five maj...
Comparative quantification of nucleic acids using single-molecule detection and molecular beacons

This paper reports a highly sensitive homogenous method for comparative quantification of nucleic acids based on single-molecule detection (SMD) and molecular beacons (MBs). Two different color MBs were used to perform a separation-free comparative hybridization assay for simultaneous quantification of both target and control strands. A fluorescent burst, emitted from a single hybrid when it passes through a minuscule laser-focused region, is detected with high signal-to-noise ratio (SNR) by using single-molecule fluorescence spectroscopy. Targets are quantified via counting of discrete fluorescent bursts. The high SNR achieved in both detection channels overcame the complications of fluorescent variability usually observed in dual-color ensemble measurements. In comparison with the conventional ensemble methods, this method improved the detection limit by 3 orders of magnitude and reduced the probe consumption by 6 orders of magnitude, facilitating a highly sensitive approach for comparative quantification of nucleic acids and offering great promise for genomic quantification without amplification.
The position of the labiate process in the diatom genus Skeletonema

The labiate process is widely found in centric diatoms and some pennate diatoms, and its placement has seemed conservative in most taxa. However, in Skeletonema, the labiate process has been observed both near the margin and near the centre of the valve. The present observations suggest that the position of the labiate process is controlled by the position of the valve in the colony. The end cells are heterovalvate, with the end valve having the more centrally located labiate process. Thus the length of chain is controlled by the production of specialized valves. The presence and placement of the labiate process still appears to be a conservative taxonomic feature.
The role of buoyancy–frequency oscillations in the generation of mountain gravity waves

There is evidence from balloon measurements that atmospheric buoyancy–frequency profiles, apart from a sharp increase (roughly by a factor of two) at the tropopause, often feature appreciable oscillations (typical wavelength 1–2 km) with altitude. It is argued here that such short-scale oscillatory variations of the background buoyancy frequency, which usually are ignored in theoretical models, can have a profound effect on the generation of mountain waves owing to a resonance mechanism that comes into play at certain wind speeds depending on the dominant oscillation wavelength. A simple linear model assuming small sinusoidal buoyancy–frequency oscillations suggests, and numerical solutions of the Euler equations for more realistic flow conditions confirm, that under resonant conditions the induced gravity-wave activity is significantly increased above and upstream of the mountain, similarly to resonant flow of finite depth over topography.
Orientational dynamics of indane dione spin-labeled myosin heads in relaxed and contracting skeletal muscle fibers

We have used electron paramagnetic resonance (EPR) spectroscopy to study the orientation and rotational motions of spin-labeled myosin heads during steady-state relaxation and contraction of skinned rabbit psoas muscle fibers. Using an indane-dione spin label, we obtained EPR spectra corresponding specifically to probes attached to Cys 707 (SH1) on the catalytic domain of myosin heads. The probe is rigidly immobilized, so that it reports the global rotation of the myosin head, and the probe's principal axis is aligned almost parallel with the fiber axis in rigor, making it directly sensitive to axial rotation of the head. Numerical simulations of EPR spectra showed that the labeled heads are highly oriented in rigor, but in relaxation they have at least 90 degrees (Gaussian full width) of axial disorder, centered at an angle approximately equal to that in rigor. Spectra obtained in isometric contraction are fit quite well by assuming that 79 +/- 2% of the myosin heads are disordered as in relaxation, whereas the remaining 21 +/- 2% have the same orientation as in rigor. Computer-simulated spectra confirm that there is no significant population (> 5%) of heads having a distinct orientation substantially different (> 10 degrees) from that in rigor, and even the large disordered population of heads has a mean orientation that is similar to that in rigor. Because this spin label reports axial head rotations directly, these results suggest strongly that the catalytic domain of myosin does not undergo a transition between two distinct axial orientations during force generation. Saturation transfer EPR shows that the rotational disorder is dynamic on the microsecond time scale in both relaxation and contraction. These results are consistent with models of contraction involving 1) a transition from a dynamically disordered preforce state to an ordered (rigorlike) force-generating state and/or 2) domain movements within the myosin head that do not change the axial orientation of the SH1-containing catalytic domain relative to actin.
Metabolites in ventricular cerebrospinal fluid detected by proton magnetic resonance spectroscopic imaging.

Normally, ventricular cerebrospinal fluid (CSF) contains low levels of all metabolite signals on proton magnetic resonance spectroscopic imaging (MRSI). We present here three cases (two with seizure disorders, one with a central nervous system lymphoma) who presented with unusually elevated CSF signals on MRSI. Based on chemical shifts and in vitro studies (in one case), the signals were assigned to propan-1,2-diol (PD), acetone, and lactate, respectively. These compounds were either exclusively, or more readily, detected in CSF than in brain. Proton MRSI conveniently screens both brain and CSF for abnormal metabolism simultaneously. J. Magn. Reson. Imaging 2004;20:496–500. © 2004 Wiley-Liss, Inc.
Regulation of membrane protein function by lipid bilayer elasticity-a single molecule technology to measure the bilayer properties experienced by an embedded protein.

Membrane protein function is generally regulated by the molecular composition of the host lipid bilayer. The underlying mechanisms have long remained enigmatic. Some cases involve specific molecular interactions, but very often lipids and other amphiphiles, which are adsorbed to lipid bilayers, regulate a number of structurally unrelated proteins in an apparently non-specific manner. It is well known that changes in the physical properties of a lipid bilayer (e.g., thickness or monolayer spontaneous curvature) can affect the function of an embedded protein. However, the role of such changes, in the general regulation of membrane protein function, is unclear. This is to a large extent due to lack of a generally accepted framework in which to understand the many observations. The present review summarizes studies which have demonstrated that the hydrophobic interactions between a membrane protein and the host lipid bilayer provide an energetic coupling, whereby protein function can be regulated by the bilayer elasticity. The feasibility of this 'hydrophobic coupling mechanism' has been demonstrated using the gramicidin channel, a model membrane protein, in planar lipid bilayers. Using voltage-dependent sodium channels, N-type calcium channels and GABAA receptors, it has been shown that membrane protein function in living cells can be regulated by amphiphile induced changes in bilayer elasticity. Using the gramicidin channel as a molecular force transducer, a nanotechnology to measure the elastic properties experienced by an embedded protein has been developed. A theoretical and technological framework, to study the regulation of membrane protein function by lipid bilayer elasticity, has been established.
Epigenetic toxicity of hydroxylated biphenyls and hydroxylated polychlorinated biphenyls on normal rat liver epithelial cells.

2-Biphenylol, 3-biphenylol, 2,2‘-biphenyldiol, 3,3‘-biphenyldiol, 3-chloro-2-biphenylol, and 4,4‘-dichloro-3-biphenylol were evaluated using the scrape-loading/dye transfer (SL/DT) technique to determine in vitro gap junctional intercellular communication (GJIC) in a normal rat liver epithelial cell line as a measure of the epigenetic toxicity. Cytotoxicity was determined using the neutral red uptake assay. A dose range of 0−300 μM was examined. Only 3,3‘-biphenyldiol and 4,4‘-dichloro-3-biphenylol induced cytotoxicity within the tested dose ranges. Noncytotoxic doses were selected for evaluation of epigenetic toxicity. 4,4‘-Dichloro-3-biphenylol was most inhibitory to GJIC at the lowest dose. The cytotoxicity and GJIC inhibitory effects observed for 4,4‘-dichloro-3-biphenylol might be, although not exclusively, a consequence of the lipophilic nature of this chemical. 3-Chloro-2-biphenylol was least inhibitory to GJIC. 3-Chloro-2-biphenylol was less inhibitory to GJIC than 2-biphenylol because of the pres...
Consistency, Superconsistency, and Dual Degeneracy in Posynomial Geometric Programming

This paper gives a method by which any consistent geometric programming problem may be reduced to a superconsistent or unconstrained geometric programming problem. We show that a consistent geometric programming problem is not superconsistent if and only if the dual geometric programming problem has an unbounded optimal solution set or an unattained supremum. Reduction of the dual to canonical form, i.e., reduction to an equivalent problem with a bounded optimal solution set, is shown to be dual to the reduction of a consistent primal program to an equivalent superconsistent program.
Rotation periods, variability properties and ages for Kepler exoplanet candidate host stars

We report rotation periods, variability characteristics, gyrochronological ages for �950 of the Kepler Object of Interest host stars. We find a wide dispersion in the amplitude of the photometric variability as a function of rotation, likely indicating differences in the spot distribution among stars. We use these rotation periods in combination with published spectroscopic measurements of vsini and stellar parameters to derive the stellar inclination in the line-of-sight, and find a number of systems with possible spin-orbit misalignment. We additionally find several systems with close-in planet candidates whose stellar rotation periods are equal to or twice the planetary orbital period, indicative of possible tidal interactions between these planets and their parent stars. If these systems survive validation to become confirmed planets, they will provide important clues to the evolutionary history of these systems. Subject headings: stars: activity — stars: rotation — stars: planetary systems
Intensity of aggressive interactions modulates testosterone in male marmosets.

Androgen is associated with the expression of male-typical behavior, including aggressive behavior, but high levels of androgen may be incompatible with other behavioral systems, such as paternal care. In a variety of species of birds that display paternal care, testosterone (T) levels in males are maintained at low levels, and these levels rise only in response to direct agonistic challenges. This idea has not been thoroughly studied in mammals with biparental care, and we exposed male marmosets (Callithrix kuhlii), a monogamous and biparental primate to aggressive interactions with unfamiliar intruders. Urinary levels of T and cortisol (CORT) were monitored prior to and following these interactions. Baseline T was not correlated with variation in aggression in either residents or intruders, and CORT was not affected by the encounters. However, males responded to an encounter with male intruders with changes in T that correlated with the level of aggression displayed by the resident male during the trial. Encounters with male intruders that elicited high frequencies of aggressive displays by the male resident were associated with increased T 2–6 h and 24 h following the encounter, and encounters that had few aggressive displays resulted in no change or a decrease in T concentrations. Intruders did not demonstrate a significant relationship between T and aggression. Thus, the magnitude of the hormonal response is dependent on the intensity of aggression during a male–male encounter, suggesting that elevated androgens are likely to be a consequence, rather than a cause, of aggressive interactions in marmosets.
The impact of purchasing policy on electronic markets and electronic hierarchies

Abstract Markets and heirarchies are two mechanisms used by organizations to coordinate steps through the value chain. For the last twenty years information technology has been used to enhance both of these coordination structures. It has been suggested (Malone et al.) that the improvement of information technology price/performance will have a more profound effect on markets leading to an increase in transactions coordinated by markets. This paper investigates the feasibility of electronic markets in light of the purchasing policy dictated by corporate strategy. Specifically, we will discuss principles of purchasing which would impede or prevent the adoption of electronic markets. We have supplemented our discussion with results from a market research survey which sought impressions of issues involved with an electronic market.
Development and optimization of shaped NMR pulses for the study of coupled spin systems

Abstract Asymmetric amplitude modulated radio frequency pulses for narrow-band inversion of coupled and uncoupled spin systems in NMR are introduced. We also introduce a new parameterization for pulse shapes using cubic spline interpolation that reduces the number of parameters. The spin response is obtained using a full density matrix calculation and pulse shapes were optimized numerically using a simplex algorithm. Coupling is shown to interfere with the performance of shaped pulses designed to invert uncoupled spins prompting the design of pulses that invert a model system consisting of two dipolar coupled spins 1 2 . Amplitude modulated shaped pulses optimized for coupled systems are found to be specific for coupling strength and spin topology.
Another view of transport system analysis

The components and interworkings of transport systems are outlined and described and some directions for improving our analysis capabilities are indicated. Particular emphasis is placed on the subject of demand analysis and on viewing the demand for travel as a dependent relationship between quantity of travel and the quality and price of travel rather than as a fixed "point estimate" or "requirement." Some explicit demand models are offered for improving our travel forecasting processes, and their relationships to price and performance functions are described both qualitatively and quantitatively; in so doing, the important characteristics of and ways for representing the time-dependent performance conditions of transport facilities are explained. Buttressing the discussion of forecasting techniques-of demand, price, and performance functions and their character, development, and interrelationships-is a section noting the importance of describing the differential as well as aggregate effects of alternative designs or policies, all as part of the system analysis.
Category-Driven Approach for Local Related Business Recommendations

When users search online for a business, the search engine may present them with a list of related business recommendations. We address the problem of constructing a useful and diverse list of such recommendations that would include an optimal combination of substitutes and complements. Substitutes are similar potential alternatives to the searched business, whereas complements are local businesses that can offer a more comprehensive and better rounded experience for a user visiting the searched locality. In our problem setting, each business belongs to a category in an ontology of business categories. Two businesses are defined as substitutes of one another if they belong to the same category, and as complements if they are otherwise relevant to each other. We empirically demonstrate that the related business recommendation lists generated by Google's search engine are too homogeneous, and overemphasize substitutes. We then use various data sources such as crowdsourcing, mobile maps directions queries, and the existing Google's related business graph to mine association rules to determine to which extent do categories complement each other, and establish relevance between businesses, using both category-level and individual business-level information. We provide an algorithmic approach that incorporates these signals to produce a list of recommended businesses that balances pairwise business relevance with overall diversity of the list. Finally, we use human raters to evaluate our system, and show that it significantly improves on the current Google system in usefulness of the generated recommendation lists.
Extended x-ray absorption fine structure investigations of Nb3Ge0.26Al0.74

Abstract We have performed Extended X-ray Absorption Fine Structure (EXAFS) studies of the high-Tc ternary superconducting alloy Nb3Ge0.26Al0.74 above the Ge K-edge. The EXAFS indicates that the local environment surrounding the Ge atoms is characterized by a high degree of structural order, similar to that found in previous investigations of high-Tc Nb3Ge thin films. We also present direct “microscopic” structural evidence that this material is a solid solution of Nb3Ge and Nb3Al. No evidence of Nb3Ge microcrystals is observed.
Ionization potential for ground states of berylliumlike systems.

The 1s 2 2s 2 ground-state energies of berylliumlike systems are calculated with a full-core plus correlation method. A partial saturation of a basis-function method is used to extrapolate a better nonrelativistic energy. The 1s 2 2s 2 ionization potentials are calculated by including the relativistic corrections, mass polarization, and QED effects. These results are compared with the existing theoretical and experimental data in the literature. The predicted Be I, C III, N IV, and 0 V ionization potentials are within the quoted experimental error
A model for intracellular trafficking of adenoviral vectors.

Here we develop an integrative computational framework to model biophysical processes involved in viral gene delivery. The model combines reaction-diffusion-advection equations that describe intracellular trafficking with kinetic equations that describe transcription and translation of the exogenous DNA. It relates molecular-level trafficking events to whole-cell distribution of viruses. The approach makes use of the current understanding of cellular processes and data from single-particle single-cell imaging experiments. The model reveals two important parameters that characterize viral transport at the population level, namely, the effective velocity, Veff, and the effective diffusion coefficient, Deff. Veff measures virus's net movement rate and Deff represents the total dispersion rate. We employ the model to study the influence of microtubule-mediated movements on nuclear targeting and gene expression of adenoviruses of type 2 and type 5 in HeLa and A549 cells. Effects of microtubule organization and the presence of microtubule-destabilizing drugs on viral transport were analyzed and quantified. Model predictions agree well with experimental data available in literature. The paper serves as a guide for future theoretical and experimental efforts to understand viral gene delivery.
‘Eddy’ Diffusion in Chromatography

AMONG the various diffusion and kinetic factors which are responsible for smearing chromatographic zones, the effect known as ‘eddy’ diffusion has been subject to the most controversy. Its contribution to the height equivalent to a theoretical plate (H) is usually assumed to depend only upon the packing of a column and to be independent of the velocity of flow. This assumption may be questioned by virtue of recent experimental work in chromatography1–3. An equation will be derived here which predicts ‘eddy’ diffusion to be dependent on velocity. This will be compared to the existing experimental evidence.
Size effects in indentation response of thin films at the nanoscale: A molecular dynamics study

Abstract The indentation response of Ni thin films of thicknesses in the nanoscale was studied using molecular dynamics simulations with embedded atom method (EAM) interatomic potentials. A series of simulations were performed in films in the [1 1 1] orientation with thicknesses varying from 4 to 12.8 nm. The study included both single crystal films and films containing low angle grain boundaries perpendicular to the film surface. The simulation results for single crystal films show that as film thickness decreases larger forces are required for similar indentation depths but the contact stress necessary to emit the first dislocation under the indenter is nearly independent of film thickness. The low angle grain boundaries can act as dislocation sources under indentation. The mechanism of preferred dislocation emission from these boundaries operates at stresses that are lower as the film thickness increases and is not active for the thinnest films tested. These results are interpreted in terms of a simple model.
Stopped Myopic Policies in Some Inventory Models with Generalized Demand Processes

This paper considers single-item inventory systems with immediate delivery and no economies of scale. Bounds are provided on the value loss relative to optimal cost for restricting attention to the class of inventory stocking policies that behave myopically up to a specified stopping time. The stopping time may be random, and may depend on demand histories as well as information exogenous to the firm. The bounds are robust to the nature of the demand process faced after the stopping time, so are applicable when the statistics of demand after the stopping time are unknown. Stopping times that are large with high probability imply that near-term decisions are completely specified with high probability. The general bounding results allow one to consider demand processes that may otherwise be analytically intractable. It is shown that the class of demand models for which the assumption of additive i.i.d. shocks is appropriate is the same class admitting effective myopic stocking policies. The bounds also make rigorous the intuitive notion that myopic policies are least effective in systems with precipitous drops in demand coupled with an inability to recover cash invested in inventory. The option of selling inventory at discount is a reality in many real systems and enhances the attractiveness of the myopic stocking policy. In numerical examples, the myopic policy is shown to be an effective competitor in a range of systems for which optimal policies are not known. The results suggest that for systems with immediate delivery, no economies of scale, and no currently known optimal policy, the myopic stocking rule is a reasonable default policy to adopt.
Influence of solar ultraviolet-B radiation on Antarctic terrestrial plants: Results from a 4-year field study

We examined the influence of solar ultraviolet-B radiation (UV-B; 280-315 nm) on the performance of Antarctic vascular plants (Colobanthus quitensis and Deschampsia antarctica) by placing filters that either absorbed or transmitted most solar UV-B over tundra along the Antarctic Peninsula for four consecutive growing seasons. The difference in biologically effective UV-B levels between our treatments was 65%, which was similar to the enhancement in ambient UV-B levels that appeared attributable to ozone depletion during the first 2 months of the growing season (November and December) at our site (62%). In both species, exposure to UV-B reduced vegetative growth, primarily through slower leaf elongation rates that led to shorter fully expanded leaves. In C. quitensis, exposure to UV-B also led to reductions in leaf longevity, branch production, cushion diameter growth, aboveground biomass, and thickness of the non-green cushion base and litter layer. Exposure to UV-B accelerated the development of reproductive structures and increased the number of panicles (D. antarctica) and capsules (C. quitensis) that reached maturity per unit of ground surface area covered by mother plants. However, this effect was offset by a tendency for these panicles and capsules to produce fewer spikelets and seeds. Ultimately, UV-B exposure did not effect the numbers of spikelets or seeds produced per unit of ground surface area. While seeds from plants exposed to UV-B tended to be lighter, germination rates were similar between UV-B treatments. The relative reductions in leaf elongation rates in D. antarctica attributable to UV-B exposure increased from the first (23%) through the fourth (43%) growing season, and relative reductions in leaf longevity in C. quitensis tended to increase from the first (9%) through the fourth (19%) growing season, suggesting that UV-B growth responses tended to be cumulative over successive years.
Exciton-exciton annihilation in poly (p-phenylenevinylene) films

Abstract We have measured the saturation of fluorescence intensity with increasing excitation intensity and the time dependence of fluorescence intensity decay at high excitation intensities in poly (p-phenylenevinylene) films. The experimental results are consistent with the hypothesis that exciton-exciton annihilation reduces the exciton lifetime at high exciton concentrations and that the exciton diffusion coefficient is quite high. We conclude that the lowest energy electronic transition creates a Frenkel exciton rather than a free-carrier pair in a band-to-band transition.
The role of 99mtechnetium dimercapto-succinic acid renal scans in the evaluation of occult ectopic ureters in girls with paradoxical incontinence

ABSTRACTPurpose: We describe the use of99m technetium (Tc) dimercapto-succinic acid (DMSA) renal scintigraphy to document poorly functioning and/or ectopic renal units associated with occult ectopic ureters.Materials and Methods: During the last 8 years 6 toilet-trained girls were referred for lifelong continuous urinary dribbling. Initial radiological evaluation included renal and bladder sonography in 6, excretory urography in 4, a mercaptoacetyltriglycine-3 renal scan in 1 and cystovaginoscopy in 2. Ultimately a99m Tc-DMSA renal scan was performed in all 6 girls before surgical intervention.Results: Sonography failed to establish the diagnosis of ureteral ectopia in all cases, and revealed a normal solitary kidney in 3, normal kidneys in 1, an apparently uncomplicated unilateral duplication without hydroureteronephrosis in 1 and a contralateral uncomplicated duplication in 1. Excretory urography in 4 cases was inconclusive and showed a solitary kidney in 1, ipsilateral duplication without a normal appe...
Vertebral artery dissection and migraine headaches in children.

Strokes of the posterior circulation are uncommon in childhood. In vertebrobasilar insults, vertebral artery dissection remains a rare diagnosis. We report the case of an 8-year-old boy with a history of migraine headaches who presented with acute cerebellar signs and agitation following multiple infarctions of bilateral cerebellar hemispheres. Vertebral angiography demonstrated dissection of the left vertebral artery with occlusion of the basilar artery just distal to its origin. Risk factors for vertebral artery dissection are reviewed, with emphasis on association with migraine headaches. A review of imaging studies for the diagnosis of dissection is also presented. This case demonstrates the importance of considering arterial wall dissection in pediatric patients with a history of atypical migraines associated with new neurologic findings. (J Child Neurol 2000;15:694-696).
Generation of small neutrino Majorana masses in a Randall-Sundrum model

I propose a model, in the framework of five dimensions with warped geometry, in which small neutrino Majorana masses are generated by tree-level coupling of lepton doublets to a $SU(2{)}_{L}$-triplet scalar field, which is coupled to a bulk standard model singlet. The neutrino mass scale is determined by the bulk mass term $({\ensuremath{\alpha}}_{S})$ of the singlet as $v{e}^{\ensuremath{-}2({\ensuremath{\alpha}}_{S}\ensuremath{-}1)\ensuremath{\pi}kR}$. This suppression is due to a small overlap between the profile of the singlet zero mode and the triplet, which is confined to the TeV brane. The generic form for the neutrino mass matrix due to the overlap between the fermions is not compatible with the large mixing angle solution. This is overcome by imposing a ${Z}_{4}$ symmetry, which is softly broken by couplings of the triplet Higgs to the lepton doublets. This model successfully reproduces the observed masses and mixing angles in the charged lepton sector as well as in the neutrino sector, in addition to having a prediction of $|{U}_{e3}|\ensuremath{\sim}\mathcal{O}(0.01)$. The mass of the triplet is of the order of a TeV and could be produced at upcoming collider experiments. The doubly charged member of the triplet can decay into two same sign charged leptons, yielding the whole triplet coupling matrix which, in turn, gives the mixing matrix in the neutrino sector.
Disparities in Wheelchair Procurement by Payer Among People With Spinal Cord Injury

Objective To identify insurance provider-related disparities in the receipt of lightweight, customizable manual wheelchairs or power wheelchairs with programmable controls among community-dwelling people with spinal cord injury (SCI). Setting Six Spinal Cord Injury Model System centers. Design A multicenter cross-sectional study. Participants A total of 359 individuals at least 16 years of age or older and 1 year after SCI who use a manual or power wheelchair as their primary means of mobility. The subjects were stratified by payer, and payers were grouped according to reimbursement characteristics as follows: Medicaid/Department of Vocational Rehabilitation (DVR), private/prepaid, Medicare, Worker's Compensation (WC)/Veterans Affairs (VA), and self pay. Methods Demographic, wheelchair, and payer data were collected by medical record review and face-to-face interview. Results There were 125 participants in the Medicaid/DVR group, 120 in the private/prepaid group, 55 in the Medicare group, 30 in the WC/VA group, and 29 in the self-pay group. For manual wheelchair users, the likelihood of having a lightweight, customizable wheelchair was 97.5% for private/prepaid, 96.3% for Medicaid/DVR, 94.1% for WC/VA, 87.5% for Medicare, and 82.6% for self pay. For power wheelchair users, those with WC/VA (100%) were most likely to receive a customizable power wheelchair with programmable controls, followed by private/prepaid (95.1%), Medicaid/DVR (86.0 %), Medicare (83.9%), and self pay (50.0%). Conclusions The only payer group for which all beneficiaries received wheelchairs that met standard of care were power wheelchairs provided by WC/VA. Fewer than 90% of people whose manual wheelchair was paid for by Medicare and self pay, and whose power wheelchair was paid for by Medicaid/DVR, Medicare, and self pay did not meet standard of care. Although these findings need to be correlated with long-term risks, such as overuse injuries, breakdowns, and participation, this study demonstrates that disparities in wheelchair procurement by insurance provider persist.
Thermal transformation of alumina trihydrate, bayerite

The thermal transformation of bayerite (alumina trihydrate) to α-alumina has been studied by X-ray diffraction and infra-red spectra. The bayerite was prepared by treatment of sodium aluminate solution with carbon dioxide. It is concluded that the thermal transformation of bayerite proceeds in the following sequence: .
Mass Conservation and the Anelastic Approximation

Abstract Numerical anelastic models solve a diagnostic elliptic equation for the pressure field using derivative boundary conditions. The pressure is therefore determined to within a function proportional to the base-state density field with arbitrary amplitude. This ambiguity is removed by requiring that the total mass be conserved in the model. This approach enables one to determine the correct temperature field that is required for the microphysical calculations. This correct, mass-conserving anelastic model predicts a temperature field that is an accurate approximation to that of a compressible atmosphere that has undergone a hydrostatic adjustment in response to a horizontally homogeneous heating or moistening. The procedure is demonstrated analytically and numerically for a one-dimensional, idealized heat source and moisture sink associated with moist convection. Two-dimensional anelastic simulations compare the effect of the new formulation on the evolution of the flow fields in a simulation of the...
The Changing Face of Research in Community Practice

The historical strengths of community-based research and dedication to improving patients outcomes and cancer care experience provide the perseverance to face uncertainties such as advances in science and technology, changes in practice environment, and demonstrating quality and value-based performance.
Magnetic Hyperfine Effects and Electronic Structure of NO

The theory of magnetic hyperfine structure in diatomic molecules is briefly reexamined. Previously reported hyperfine effects in the ${\mathrm{N}}^{14}$${\mathrm{O}}^{16}$ molecule, both magnetic and electric quadrupole, are interpreted with corrected theoretical expressions in terms of an electronic structure consisting of 65 percent N=O and 35 percent ${\mathrm{N}}^{\ensuremath{-}}$=${\mathrm{O}}^{+}$. The unpaired electron is shown to be essentially in a $2p$ $\ensuremath{\pi}$ orbital but with 2.5 percent $s$ character. Discrepancies of about 8 percent between experimental and calculated values of the magnetic hyperfine constants indicate limitations in the use of atomic wave function approximations for electronic orbitals.
The effect of environment on computer science curriculum

In this paper by tracing the history of the programs and outlining the programs themselves, a comparison will be made of the factors that lead to the creation and development of a computer science program in a large state university and in a small liberal arts college. In the first case the program leads to a baccalaureate degree in computer science. In the second it is a branch of the mathematics curriculum.Along with the factors of educational philosophy environmental factors such as the relationship of the department to the institution, equipment desired and available, the relationship to the computer center and facilities for faculty development will be considered.
Multiprocessor Smalltalk: a case study of a multiprocessor-based programming environment

We have adapted an interactive programming system (Smalltalk) to a multiprocessor (the Firefly). The task was not as difficult as might be expected, thanks to the application of three basic strategies: serialization, replication, and reorganization. Serialization of access to resources disallows concurrent access. Replication provides multiple instances of resources when they cannot or should not be serialized. Reorganization allows us to restructure part of the system when the other two strategies cannot be applied.We serialized I/O, memory allocation, garbage collection, and scheduling, we replicated the interpreter process, software caches, and a free-list, and we reorganized portions of the scheduling system to deal with some deep-seated assumptions. Our changes yielded a fairly low static overhead. We attribute our success to the choice of a small, flexible operating system, a set of constraints which simplified the problem, and the versality of the three strategies for dealing with concurrency. The current system has a moderate amount of overhead when parallelism is being used—25% to 65%. It is acceptable, but we believe it can be improved.
Reading Instruction for Elementary-Age Students with Emotional and Behavioral Disorders: Academic and Behavioral Outcomes

This study evaluated the effects of a reading intervention on the reading achievement and social behaviors of 6 third-grade students with emotional/behavioral disorders. Reading instruction occurred 4 days a week using the Horizons Fast Track reading program and Peer-Assisted Learning Strategies. Analyses indicated variable improvements in basic reading skills with limited transfer to oral reading fluency. Outcomes for social behaviors indicated that changes in total inappropriate behavior were not directly related to the reading intervention; improved engagement appeared related to intervention but not necessarily reading achievement. Results are discussed in the context of possible reasons for differential responding and implications for practice and future research.
NMR Observable-Based Structure Refinement of DAP12-NKG2C Activating Immunoreceptor Complex in Explicit Membranes

NMR observables, such as NOE-based distance measurements, are increasingly being used to characterize membrane protein structures. However, challenges in membrane protein NMR studies often yield a relatively small number of such restraints that can create ambiguities in defining critical side chain-side chain interactions. In the recent solution NMR structure of the DAP12-NKG2C immunoreceptor transmembrane helix complex, five functionally required interfacial residues (two Asps and two Thrs in the DAP12 dimer and one Lys in NKG2C) display a surprising arrangement in which one Asp side chain faces the membrane hydrophobic core. To explore whether these side-chain interactions are energetically optimal, we used the published distance restraints for molecular dynamics simulations in explicit micelles and bilayers. The structures refined by this protocol are globally similar to the published structure, but the side chains of those five residues form a stable network of salt bridges and hydrogen bonds, leaving the Asp side chain shielded from the hydrophobic core, which is also consistent with available experimental observations. Moreover, the simulations show similar short-range interactions between the transmembrane complex and lipid/detergent molecules in micelles and bilayers, respectively. This study illustrates the efficacy of NMR membrane protein structure refinements in explicit membrane systems.