cssi/SciSciGPT-SciSciNet huggingface dataset:
Optical deformation potential and self-trapped excitons in 2D hybrid perovskites

Self-trapped excitons (STEs) in two-dimensional (2D) hybrid organic–inorganic perovskites (HOIPs) emit broadband white light, suggesting the great potential of 2D HOIPs in low-cost lighting and display applications. A prerequisite for understanding STEs' properties is a correct identification of the underlying interaction that leads to the STEs. Here, we show that the long-range polar coupling between electrons and optical phonons is quenched in 2D HOIPs' tightly bound excitons and cannot effect STEs. Rather, the STEs are induced by a short-range optical deformation potential (ODP) arising from the phonon-modulated Pb–X quantum-well thickness. Interaction between transition dipoles in adjacent PbX6 (X = Br or I) octahedra gives rise to highly anisotropic intra- and inter-layer exciton bandwidths. In flat (001) 2D HOIPs, both the ODP and the exciton bandwidths are susceptible to out-of-plane PbX6 tilting but not to the in-plane one, and their interplay can quantitatively account for the observed temperature and structure dependences of luminescence associated with STEs. In corrugated (011) 2D HOIPs, the exciton bandwidth is further reduced and the resultant STEs have a stronger lattice distortion and broader luminescence spectrum. Our results reveal the mechanism of STE formation and suggest ways of tuning STEs and associated broadband luminescence in 2D HOIPs.
Nudging Emergency Care Providers to Reduce Opioid Prescribing Using Peer Norm Comparison Feedback: A Pilot Randomized Trial.

OBJECTIVE To determine the feasibility, acceptability, and potential impact of using audit and feedback (A&F) with or without peer norm comparison on opioid prescribing by emergency medicine providers. METHODS A convenience sample of 37 emergency medicine providers were recruited from 16 emergency departments in Western Pennsylvania for a pilot randomized controlled trial. Participants completed a baseline survey, were randomly allocated to A&F (N = 17) or A&F with peer norm comparison (N = 20), and were asked to complete a postintervention survey. We matched each participant 1:1 to a control who was not exposed to either intervention. RESULTS At baseline, 57% of participants perceived that they prescribed opioids at the same frequency as their peers, whereas 32% perceived prescribing less than and 11% perceived prescribing more than their peers. Most participants rated the interventions as helpful, with no differences between conditions. For the A&F with peer norm comparison condition, from pre- to postintervention, there was a relative increase of 20% in the percentage of participants who perceived that they prescribed more opioids than their peers but no change in the A&F condition (P = 0.02). 56.8% of controls, 52.9% of A&F participants, and 75.5% of A&F with peer norm comparison participants reduced their opioid prescribing (P = 0.33). The mean reduction in opioid prescriptions (SD) was 3.3. (9.6) for controls, 3.9 (10.5) for A&F, and 7.3 (7.8) for A&F with peer norm comparison (P = 0.31). CONCLUSIONS Audit and feedback interventions with peer norm comparisons are helpful to providers, can alter perceptions about prescribing norms, and are a potentially effective way to alter ED providers' opioid prescribing behavior.
Direct and stable weight adjustment in non‐experimental studies with multivalued treatments: analysis of the effect of an earthquake on post‐traumatic stress

In February 2010, a massive earthquake struck Chile, causing devastation in certain parts of the country, affecting other areas, and leaving territories untouched. 2 months after the earthquake, Chile's Ministry of Social Development reinterviewed a representative subsample of its National Socioeconomic Characterization Survey, which had been completed 2 months before the earthquake, thereby creating a prospective longitudinal survey with detailed information of the same individuals before and after the earthquake. We use a new weighting method for non‐experimental studies with multivalued treatments to estimate the effect of levels of exposure to the earthquake on post‐traumatic stress. Unlike common weighting approaches for multivalued treatments, this new method does not require explicit modelling of the generalized propensity score and instead focuses on directly balancing the covariates across the multivalued treatments with weights that have minimum variance. As a result, the weighting estimator is stable and approximately unbiased. Furthermore, the weights are constrained to avoid model extrapolation. We illustrate this new method in a simulation study, with both categorical and continuous treatments. The results show that directly targeting balance instead of explicitly modelling the treatment assignment probabilities tends to provide the best results in terms of bias and root‐mean‐square error. Using this method, we estimate the effect of the intensity of the earthquake on post‐traumatic stress. We implement this method in the new package msbw for R.
Economic evaluation of suture versus clip anastomosis in arteriovenous fistula creation.

Abstract Objective Techniques such as the use of nonpenetrating vascular clips for arteriovenous fistula (AVF) anastomotic creation have been developed in an effort to reduce fistula-related complications. However, the outcomes data for the use of clips have remained equivocal, and the cost evaluations to support their use have been largely theoretical. Therefore, the present study aimed to determine both the clinical and the cost outcomes of AVFs created with nonpenetrating vascular clips compared with the continuous suture technique during a 10-year period at a single institution. Methods All patients undergoing AVF creation in the upper extremity from 2009 through 2018 were retrospectively analyzed. The patient demographics and AVF outcomes were collected and compared stratified by the surgical technique used. A cost analysis was performed of a subgroup of patients from 2013 to 2018. Results During the 10-year study period, 916 AVFs were created (79% using the continuous suture technique and 21% using nonpenetrating vascular clips). Patient demographics and comorbid conditions did not differ between the two groups, and no differences were present in maturation, primary patency, assisted primary patency, or complication rates between the two groups at 1 year. The suture group had a shorter time to maturation (4.3 months vs 5.5 months; P Conclusions Both suture and clip techniques in AVF creation demonstrated equivalent rates of maturation, primary patency, assisted primary patency, and complications at 1 year with higher expense associated with the use of clips. Thus, in an effort to reduce the economic burden of healthcare in the United States, the findings from the present study support the preferential use of the standard polypropylene suture technique when creating upper extremity AVFs.
Chemical, Morphological, and Fundamental Properties of Rejuvenated Asphalt Binders

AbstractThis study investigates the chemical characteristics of rejuvenators and the effect of different rejuvenators on the morphology and fundamental behavior of rejuvenated asphalt binders. Gas ...
What is the state space of the world for real animals

A key concept in reinforcement learning (RL) is that of a state space. A state space is an abstract representation of the world using which statistical relations in the world can be described. The simplest form of RL, model free RL, is widely applied to explain animal behavior in numerous neuroscientific studies. More complex RL versions assume that animals build and store an explicit model of the world in memory. To apply these approaches to explain animal behavior, typical neuroscientific RL models make assumptions about the underlying state space formed by animals, especially regarding the representation of time. Here, we explicitly list these assumptions and show that they have several problematic implications. We propose a solution for these problems by using a continuous time Markov renewal process model of the state space. We hope that our explicit treatment results in a serious consideration of these issues when applying RL models to real animals.
The Quasi-Shear Rotation

A discrete one-to-one bitmap rotation called the Quasi Shear Rotation (QSR) is presented. This bitmap rotation is one-to-one, reversible and can have an arbitrary (non lattice) rotation center. The QSR represents so far the “best” choice of an one-to-one discrete rotation for a practical application.
Assistive technology as an HCI topic

Assistive technology (AT) for the disabled encompasses everything from special handles, to padding for arranging seating position, to computerized devices of various kinds. This latter category fits naturally within the area of human-computer interaction (HCI), but is largely ignored within the field (as evidenced by its cursory mention within HCI textbooks). The purpose of this workshop is to introduce assistive technology from the perspective of HCI, as a means of encouraging its inclusion within standard HCI courses. Furthermore, an entire course on AT from a computer science point of view will be discussed.
Short intense ion pulses for materials and warm dense matter research

We have commenced experiments with intense short pulses of ion beams on the Neutralized Drift Compression Experiment-II at Lawrence Berkeley National Laboratory, by generating beam spots size with radius r<1 mm within 2 ns FWHM and approximately 1010 ions/pulse. To enable the short pulse durations and mm-scale focal spot radii, the 1.2 MeV Li+ ion beam is neutralized in a 1.6-meter drift compression section located after the last accelerator magnet. An 8-Tesla short focal length solenoid compresses the beam in the presence of the large volume plasma near the end of this section before the target. The scientific topics to be explored are warm dense matter, the dynamics of radiation damage in materials, and intense beam and beam-plasma physics including selected topics of relevance to the development of heavy-ion drivers for inertial fusion energy. Finally, we describe the accelerator commissioning and time-resolved ionoluminescence measurements of yttrium aluminum perovskite using the fully integrated accelerator and neutralized drift compression components.
Cathedrals as Astronomical Instruments

The Sun in the Church Cathedrals as Solar Observatories. J. L. Heilbron. Harvard University Press, Cambridge, MA, 1999. 376 pp. $35. ISBN 0-674-85433-0. Heilbron blends discussions of astronomy, religious architecture, and Catholic history to demonstrate that the Church9s efforts to establish an unquestionable date for Easter led to evidence on the geometry of the solar system that favored the ideas for which Galileo had been condemned.
Cloning and characterization of the choline acetyltransferase structural gene (cha-1) from C. elegans

We have cloned the cha-1 gene from Caenorhabditis elegans using the method of transposon tagging, cha-1 is the structural gene for ChAT, the enzyme that synthesizes ACh. Sequence analysis of cDNAs predicts a protein of 71.5 kDa; comparison of the deduced amino acid sequence with ChAT sequences from other species confirms that cha-1 encodes ChAT. Comparison of cDNA and genomic sequences reveals that transcription is from right to left on the genetic map, and that some of the transcripts may result from trans-splicing of the 22-base spliced leader SL 1. The cha-1 gene is organized into 11 exons. The first exon contains only untranslated sequences, and is followed by an extremely long intron. The coding sequence of the cha-1 transcript is disrupted by mutations in the cha-1 gene. We have determined the sites of four transposon insertions and the end-points of two deletions that lead to the cha-1 mutant phenotype; one of the deletions appears to eliminate gene function completely. Comparison of the Drosophila, rat, and C. elegans genes reveals conserved motifs and conserved intron sites.
A Schema for Representing Medical Language Applied to Clinical Radiology

Objective : Develop a representational schema for clinical concepts and apply it to the task of encoding radiology reports of the chest. Design : The schema was developed following a manual analysis of sample reports from the domain. The schema has two main components: the Medical Entities Dictionary (MED), which specifies the formal representation of the concepts in the domain and of their structures, and the natural-language processor, which specifies the linguistic expressions of the concepts. The schema was evaluated by applying it to a test set of 7,500 reports. Two-hundred reports from the test set were manually analyzed by a medical expert to determine the accuracy and success rate of the system. Results : 82% of the 7,500 reports that contained relevant clinical information were successfully structured automatically. For the smaller set of 200 reports, 80% were structured successfully with an accuracy rate of 97%. Conclusions : The schema is a formal representation for clinical concepts in radiology reports, and provides domain coverage that is particularly well-suited for natural-language processing of radiology for use in a decision support system.
The B2B Agenda: The Current State of B2B Marketing and a Look Ahead

► Corporate expectations from marketing are increasing and the stakes are getting higher. ► Global markets have created unprecedented challenges for B2B marketers. ► Technology’s disruptive power could make certain B2B marketing practices obsolete. ► The biggest challenges to marketing are company-wide, requiring stronger interfaces with other functions. ► Marketing must engage more deeply with customers and demonstrate its contribution to business performance.
Comparisons of methods of estimation for a Pareto distribution of the first kind

This paper compares methods of estimation for the parameters of a Pareto distribution of the first kind to determine which method provides the better estimates when the observations are censored, The unweighted least squares (LS) and the maximum likelihood estimates (MLE) are presented for both censored and uncensored data. The MLE's are obtained using two methods, In the first, called the ML method, it is shown that log-likelihood is maximized when the scale parameter is the minimum sample value. In the second method, called the modified ML (MML) method, the estimates are found by utilizing the maximum likelihood value of the shape parameter in terms of the scale parameter and the equation for the mean of the first order statistic as a function of both parameters. Since censored data often occur in applications, we study two types of censoring for their effects on the methods of estimation: Type II censoring and multiple random censoring. In this study we consider different sample sizes and several value...
Summary of the GASP code application and evaluation effort for scramjet combustor flowfields

Numerical simulations of 3D turbulent mixing and reacting flows have been systematically evaluated by comparison with experimental data and other numerical solutions to provide confidence in the General Aerodynamic Simulation Program (GASP) code version 1.3. Specifically, the GASP flow solver has been used to model high speed flow through scram jet combustors. Unit injector problems evaluated include (1) UVA staged sonic normal injection of air into Mach 2 air stream, (2) the VPI Mach 1.7 low angled (15 deg) flush wall helium injection into an unconfined Mach 6 'cold air' stream, and (3) the HYPULSE angled (30 deg) flush wall hydrogen injection into a Mach 6, high enthalpy (flight Mach 17 simulation) nitrogen and air test gases. Results of the numerical simulation for the first two test cases have been compared with detailed in-stream measurements and with SPARK CFD solutions. The results for the last two cases have been compared with measured wall pressure and heat flux data and with SPARK CFD solutions. The present GASP solutions compare favorably with both the experimental data and the SPARK solutions.
Combined effects of temperature acclimation and cadmium exposure on mitochondrial function in eastern oysters Crassostrea virginica gmelin (Bivalvia: Ostreidae).

Cadmium and temperature have strong impacts on the metabolic physiology of aquatic organisms. To analyze the combined impact of these two stressors on aerobic capacity, effects of Cd exposure (50 μg/L) on mitochondrial function were studied in oysters (Crassostrea virginica) acclimated to 12 and 20°C in winter and to 20 and 28°C in fall. Cadmium exposure had different effects on mitochondrial bioenergetics of oysters depending on the acclimation temperature. In oysters acclimated to 12°C, Cd exposure resulted in elevated intrinsic rates of mitochondrial oxidation, whereas at 28°C, a rapid and pronounced decrease of mitochondrial oxidative capacity was found in Cd-exposed oysters. At the intermediate acclimation temperature (20°C), effects of Cd exposure on intrinsic rates of mitochondrial oxidation were negligible. Degree of coupling significantly decreased in mitochondria from 28°C-acclimated oysters but not in that from 12°C- or 20°C-acclimated oysters. Acclimation at elevated temperatures also increased sensitivity of oyster mitochondria to extramitochondrial Cd. Variation in mitochondrial membrane potential explained 41% of the observed variation in mitochondrial adenosine triphosphate synthesis and proton leak between different acclimation groups of oysters. Temperature-dependent sensitivity of metabolic physiology to Cd has significant implications for toxicity testing and for extrapolation of laboratory studies to field populations of aquatic poikilotherms, indicating the importance of taking into account the thermal regime of the environment.
A historical oversight: Vladimir P. Kolgan and his high-resolution scheme

The Russian landmark paper ''Application of the principle of minimizing the derivative to the construction of finite-difference schemes for computing discontinuous solutions of gas dynamics'' by Vladimir P. Kolgan is discussed in a historical-technical perspective. The 1972 paper already featured a Godunov-type scheme for the Euler equations with second-order spatial accuracy, and a limiter to make it monotonicity-preserving. The work remained little known within and completely unknown outside the USSR, largely because of Kolgan's untimely death in 1978. To honor Kolgan's contribution to CFD, an English translation of his paper is included in this issue of the Journal of Computational Physics. Facts about Kolgan's life are presented here, and an appraisal is given of the originality of his ideas.
Perception updating and day-to-day travel choice dynamics in traffic networks with information provision

A Bayesian updating model is developed to capture the mechanism by which travelers update their travel time perceptions from one day to the next in light of information provided by Advanced Traveler Information Systems (ATIS) and their previous experience. The availability and perceived quality of traffic information are explicitly modeled within the proposed framework. The uncertainty associated with a driver's travel time estimate is modeled in a stochastic dynamic framework and is incorporated in a travel choice model. Each driver uses a disutility function of perceived travel time and perceived schedule delay to evaluate the alternative travel choices, then selects an alternative based on the utility maximization principle. The perception updating model and the choice model are integrated with a dynamic traffic simulator (DYNASMART). Empirical results from the simulation experiments and their implications are also presented.
Identification of the active species in the suppression of postirradiation conductivity in polystyrene films for dosimeter application

The resistivity of insulating materials for electrostatic, ion chamber dosimeters must be very high and must remain so after exposure to ionizing radiation. Low dielectric polarization and good fabrication characteristics make hydrocarbon polymers most suitable, but both the conductivity during irradiation and its decay afterward vary greatly even for the same type of polymer, probably depending on impurities. Amorphous, styrene-based polymers and copolymers polymerized in aqueous emulsion and initiated with K2S2O8 were found to have much more rapid decay of conductivity after irradiation than pure polystyrene or other nonpolar polymers. The synthesis method incorporates sulfate groups on the polymer chain ends and leaves emulsifier residues distributed throughout the polymer as was demonstrated by various analytical procedures. To identify the trapping species a synthesis program was carried out varying selected ingredients in the polymerization recipe. It was found that the postirradiation conductivity was not dependent on the chemical nature of the emulsifier residues. On the other hand, the decay time of conductivity after irradiation did depend on the polar groups incorporated in the polymer chain. It was concluded that effective charge carrier traps were constituted of a polar second phase highly dispersed through the polymer by association with polar groups incorporated on the polymer chain.
Fabrication of Polydimethylsiloxane Phantoms for Optical Imaging Based on Quantum Dot Nanofluorophores

We describe a method for fabrication of polydimethy lsiloxane (PDMS) phantoms suitable for optical fluorescence imaging systems based on quantum dot nanofluorophores in aqueous solution, and illustrate examples of phantom designs and measurements.
Electro-hydrodynamic pumped hydraulic actuation with application to active vibration control

A new type of actuation device has been conceptualized that meets the needs of both large displacement, force and bandwidth within a package more compact than currently available magnetostrictive and stack-type piezoelectric actuators of similar rating. This concept relies on micro-scale electrohydrodynamic (EHD) pumping of a dielectric liquid within small channels. Configured as an actuator, the EHD pump(s) would be used to move fluid between two reservoirs-each having a compliant membrane that interfaces to the world to provide the means to achieve vibration cancellation or micro actuation. Ordinarily limited to generating flow in macroscale applications, the EHD pump, when operating in a thermal induction mode, is shown to exhibit an exciting scaling law as its size is reduced. As the pump volume to surface area decreases, the energy going toward increasing pressure in the pump has an increasingly larger effect. Since the volume/surface area is proportional to 1/a, where a is the characteristic width or diameter of the channels comprising the pump, the pressure head generated scales similarly. Analytical and numerical studies have shown the EHD-pumped actuator to be capable of delivering equal force and bandwidth to magnetostrictive and stack-type piezo actuators, but with considerably greater displacement and roughly 1/10 th of the size. Further, this type of actuator offers the possibility for deployment in active vibration control or micro actuation applications at significantly greater temperatures than for piezoelectric and magnetostrictive devices.
The effect of early operative stabilization on late displacement of zone I and II sacral fractures.

Abstract Introduction This study was designed to evaluate the effect on displacement of early operative stabilization on unstable fractures when compared to stable fractures of the sacrum. Methods Patient consisted of those sustaining traumatic pelvic fractures that also included sacral fractures of Denis type I and type II classification, who were over 18 at the time of the study. Patients were managed emergently, as judged appropriate at the time and then subsequently divided into two cohorts, comprising those who were either treated operatively or non-operatively. The operative group comprised those treated with either internal fixation or external fixation. Results Twenty-eight patients had zone II fractures, and 20 had zone I fractures. Zone II fractures showed average displacements of 6.5 mm and 6.9 mm in the rostral–caudal and anteroposterior directions, respectively, at final follow up. Zone I fractures had average displacements of 6.6 mm and 6.1 mm in both directions. There were no significant differences between zone I and II sacral fractures (rostral–caudal P = 0.74, anteroposterior P = 0.24). Average changes in fracture displacement in patients with zone I fractures were 0.6–1.0 mm in both directions. Average changes in zone II fractures were 1.8–1.5 mm in both directions. There were no significant differences between the average changes in zone I and II fractures in any direction (rostral–caudal P = 0.64, anteroposterior P = 0.68) or in average displacements at final follow up in any of zone or the entire cohort. Statistically significant differences were noted in average changes in displacement in zone II fractures in the anteroposterior plane (P = 0.03) and the overall cohort in the anteroposterior plane (P = 0.02). Conclusion Operative fixation for unstable sacral fractures ensures displacement at follow up is comparable with stable fractures treated non operatively.
Platelet-TLR7 mediates host survival and platelet count during viral infection in the absence of platelet-dependent thrombosis

Viral infections have been associated with reduced platelet counts, the biological significance of which has remained elusive. Here, we show that infection with encephalomyocarditis virus (EMCV) rapidly reduces platelet count, and this response is attributed to platelet Toll-like receptor 7 (TLR7). Platelet-TLR7 stimulation mediates formation of large platelet-neutrophil aggregates, both in mouse and human blood. Intriguingly, this process results in internalization of platelet CD41-fragments by neutrophils, as assessed biochemically and visualized by microscopy, with no influence on platelet prothrombotic properties. The mechanism includes TLR7-mediated platelet granule release, translocation of P-selectin to the cell surface, and a consequent increase in platelet-neutrophil adhesion. Viral infection of platelet-depleted mice also led to increased mortality. Transfusion of wild-type, TLR7-expressing platelets into TLR7-deficient mice caused a drop in platelet count and increased survival post EMCV infection. Thus, this study identifies a new link between platelets and their response to single-stranded RNA viruses that involves activation of TLR7. Finally, platelet-TLR7 stimulation is independent of thrombosis and has implications to the host immune response and survival.
Do they buy for their dogs the way they buy for themselves

Motivated by the fact that pet food and pet care is a big business and pet owners in the United States spend more on their pets each year, the objective of this research is to determine whether dog owners buy for their dogs the way they buy for themselves. The data show that dog owners are more loyal to dog food brands than human food brands. Dog owners are also found to be more sensitive to human food price than dog food price. The survey results also show that dog owners are more serious about buying healthy dog food than buying healthy human food. The findings are significant because they suggest that manufacturers and marketers of dog food and vet care service providers can gain some insight about the type of food and medical services dog owners might buy for their dogs by studying dog owners' food and medical service consumption decision patterns. © 2010 Wiley Periodicals, Inc.
Pregnancy-Associated Plasma Protein A as Predictor of Outcome in Patients With Suspected Acute Coronary Syndromes

We read with interest the article by Lund et al1 on circulating pregnancy-associated plasma protein A (PAPP-A) in 136 patients evaluated for suspected acute coronary syndrome without cardiac troponin I elevation. PAPP-A concentrations above 2.9 mIU/L during the first 24 hours independently predicted cardiovascular death, nonfatal myocardial infarction, or revascularization over the following 6 months. The risk ratio of PAPP-A >2.9 mIU/L, adjusted for C-reactive protein (CRP), age, gender, diabetes, current smoking, hypertension, previous myocardial infarction, and congestive heart failure was superior to that of CRP >2 mg/L: 4.6 for PAPP-A (95% confidence interval 1.8 to 11.8, P =0.002) versus 2.6 for CRP (95% confidence interval 1.1 to 6.5, P =0.03). The cumulative risk of an event, graded by increasing PAPP-A values, was 8% in the lowest group and 37.9% in the highest ( P =0.0012). PAPP-A and CRP levels were independent of each other ( r =−0.03, P =0.7 on admission; r =0.02, P =0.8 for peak values). These striking …
Fish school formation and maintenance: a random encounter model

Abstract A model representing the probability distribution for numbers of school for pelagic schooling fish is presented, assuming that school numbers are determined by random encounters between schools (school coalescing) and between schools and predators (school splitting). The model is a birth-death process expressed as a system of differential-difference equations for the probability of having different numbers of schools in a 1 km 2 study region. The equilibrium solution is obtained analytically and parameters determining the encounter rates between conspecifics and with predators are estimated based on the visual search radii of both predators and prey fish and their relative cruising speeds. Results are presented for different combinations of prey and predator characteristics and are interpreted to indicate under what conditions schooling is likely. The model suggests that schooling may have evolved under conditions of low predation pressure because these would allow school coalescence, but that the advantages of schools once formed in protection against predation may have solidified its selective advantage. The model also suggests that fishing pressure, which targets and removes large schools should, seriously deplete the stock before school numbers distribution will change.
Growth and change in U.S. micropolitan areas

The U.S. Census Bureau has now recognized micropolitan places, which are sometimes called emerging metropolitan areas or mini-metros. After the 1990 census, a total of 581 different non-metropolitan counties, forming 496 consolidated micropolitan areas, were assigned to this new settlement category. The first half of the paper analyzes the evolving geographic distribution and the shifting employment attributes (emphasizing job specialization) of these places during 1980–2000. Changes in the U.S. micropolitan landscape, reflecting the impressive growth of these places during the late 20th century, mirror other well-known national demographic and economic trends. The second half of the paper analyzes simultaneous population and employment change in micropolitan counties, using a series of partial adjustment models that control for various demographic, economic, and geographic factors. Evidently (initial and adjusted) population levels have induced both employment and population change in these places, but employment levels have failed to have the same impact.
A study and optimization of eigenmode calculations using the imaginary-distance beam-propagation method

Recently, it has been shown that if the paraxial wave equation is modified such that fields travel imaginary distances, the field resulting from an imaginary-distance propagation is the fundamental mode of an optical waveguide. For the finite-difference beam-propagation method, we derive the factor by which each eigenmode is amplified during one propagation step. This amplification factor places limits on the inputs-step size, input field, effective index guess, and implicitness parameter-and gives clues on how to optimize the inputs. In particular, we identify and study two optimal sets of inputs, which can reduce computational time significantly. We can obtain the fundamental mode and its propagation constant within a few propagation steps. >
WHAT'S NEW ABOUT THE NEW ECONOMIC GEOGRAPHY?

Since 1990 a new genre of research, often described as the 'new economic geography', has emerged. It differs from traditional work in economic geography mainly in adopting a modelling strategy that exploits the same technical tricks that have played such a large role in the 'new trade' and 'new growth' theories; these modelling tricks, while they preclude any claims of generality, do allow the construction of models that—unlike most traditional spatial analysis—are fully general-equilibrium and clearly derive aggregate behaviour from individual maximization. The new work is highly suggestive, particularly in indicating how historical accident can shape economic geography, and how gradual changes in underlying parameters can produce discontinuous change in spatial structure. It also serves the important purpose of placing geographical analysis squarely in the economic mainstream.
Spreading of wave packets in the Anderson model on the Bethe lattice

The spreading of wave packets evolving under the Anderson Hamiltonian on the Bethe Lattice is studied for small disorder. The mean square distance travelled by a particle in a timet is shown to grow ast2 for larget.
“Picture-in-Picture” Augmentation of UAV Workstation Video Display:

Research at the Air Force Research Laboratory has focused on determining the value of combining computer-generated information with live camera video presented on an unmanned air vehicle (UAV) station display. In a previous study, a picture-in-picture (PIP) concept (where video imagery is surrounded by synthetic-generated terrain imagery, increasing the operator's instantaneous field-of-view) was found to reduce landmark search time and enhance operator situation awareness. The present study examined whether PIP display size and symbology overlay registration error impacts performance. Results confirmed that performance on a landmark search task is better when a PIP display was used, particularly with the more compressed video imagery, reducing average designation time by 60%. Also, the registration error between the virtual flags and landmarks was less critical with the PIP capability enabled. This research has potential application to a variety of teleoperated control applications.
Epilepsy after minor head trauma

Epidemiologic studies have shown no increased risk of epilepsy after mild head injury (i.e., brief loss of consciousness or amnesia). Twelve cases of newonset epilepsy occurring ⩽6 months after mild head injury were identified. None of the patients had other risk factors for epilepsy. There was no loss of consciousness in three cases; in the remaining nine, the duration of posttraumatic unconsciousness was ⩽10 min. Nine patients had epileptiform activity or video-EEG documented epileptic seizures; two other patients had focal slowing on the EEG. Eight patients have medically refractory epilepsy, probably reflecting the selection bias. These cases suggest that in certain instances mild head trauma may cause epilepsy.
Testosterone and cortisol concentration in spermatic, adrenal and systemic venous blood in adult male guinea pigs.

Testosterone (T) and cortisol (F) concentrations were measured in spermatic vein, adrenal vein and systemic blood of adult male guinea pigs before and after 4 days of treatment with ACTH, methylprednisolone acetate (MPA), or HCG. In the untreated animal, T concentrations were 1.0 Mg/100 ml in spermatic vein blood and 0.20 jug/100 ml in cardiac blood. Spermatic vein T concentration fell with ACTH, increased with HCG, and was unchanged by MPA treatment. The testosterone concentration in cardiac blood tended to be similar to adrenal venous blood levels and was always higher than in systemic blood obtained after organ blood collection. Normal F concentration was 488 /xg/100 ml in adrenal vein and 50 /ug/100 ml in cardiac blood. ACTH increased and MPA decreased all F levels. These results indicate that the testis is the main source of T secretion in the male guinea pig although the adrenal may secrete a biologically significant amount of gonadotropin suppressing steroid during pharmacological stimulation. There was no evidence of testicular F secretion. There was evidence that T production fell while F production was less labile during the period of organ blood collection. {Endocrinology 88: 523, 1971) T ARE few reports of testosterone (T) and cortisol (F) blood concentrations in the guinea pig. Even less is known about the level of these steroids during stimulation or suppression of the adrenal cortex or Leydig cells. Received August 21,1970. This investigation was supported by Grants TIAM-5350 and HD 72, through NIH. This study measured T and F concentrations in spermatic, adrenal and systemic blood of normal adult male guinea pigs, with and without hormone treatment. 1 Present adress: Department of Medicine, The Pennsylvania State University College of Medicine, The Milton S. Hershey Medical Center. Hershey, Pa. 17033. 524 NOTES AND COMMENTS Volume 88 TABLE 1. Blood testosterone concentrations (/xg/100 ml) from untreated guinea pigs and following four days of ACTH, MPAf, or HCG administration
Choroidal neovascularization in peripapillary acute zonal occult outer retinopathy.

Background: Acute zonal occult outer retinopathy (AZOOR) is a disease of unknown etiology in young or middle-aged patients that is characterized by acute loss of one or more zones of outer retinal function, photopsia, minimal initial ophthalmoscopic changes, and electroretinographic abnormalities. AZOOR may represent part of the spectrum of a single disease, the so-called AZOOR complex. In contrast with most other ocular diseases that may be part of this AZOOR complex, AZOOR has not, to our knowledge, been reported in association with choroidal neovascularization (CNV). Case Report: We describe a 47-year-old man presenting with peripapillary AZOOR and CNV. Despite photodynamic therapy, CNV evolved to a fibrovascular diskiform scar. Conclusion: The occurrence of CNV on the margin of the AZOOR process suggested a direct link between the CNV and the underlying condition. To our knowledge, this is the first reported case of CNV complicating AZOOR.
Thoracoscopic transdiaphragmatic nephrectomy: feasibility study

Abstract Objectives. Large-sized upper pole renal or adrenal tumors are often excised by the open thoracoabdominal approach. As an adjunct to existing transperitoneal and retroperitoneal laparoscopic approaches, we explore a novel minimally invasive technique, the thoracoscopic transdiaphragmatic approach, for performing nephrectomy. Methods. Thoracoscopic transdiaphragmatic nephrectomy was performed bilaterally in 4 farm pigs (8 kidneys) using three ports placed intercostally. Results. The mean surgical time was 69.3 minutes on the left side and 74.3 minutes on the right. Blood loss was 18.7 mL. The mean size of the diaphragmatic incision was 7.2 cm. Adequate retraction of the spleen and liver was feasible during left and right-sided nephrectomy, respectively. Excellent and expeditious access to the renal hilum was routinely obtained. In 5 of 8 procedures, the diaphragmatic incision was located peripherally along the posterior margin; difficulty in suture repair of the diaphragmatic incision was noted in each instance because of the thin diaphragm in this location. During porcine left nephrectomy with ipsilateral lung collapse (n = 4), arterial blood gases and end-tidal carbon dioxide remained normal. Conclusions. Thoracoscopic transdiaphragmatic nephrectomy is feasible. This technique provides excellent and unique visualization of the renal vessels and the upper pole of the kidney and adrenal gland. When indicated, the thoracoscopic transdiaphragmatic approach, used in combination with current laparoscopic techniques, has the potential to provide the minimally invasive counterpart of the thoracoabdominal surgical approach in select patients with upper pole renal or adrenal pathologic findings.
The phage RNA polymerases are related to DNA polymerases and reverse transcriptases

The single subunit DNA-dependent RNA polymerase (RNAP) that is encoded by bacteriophage T7 is the prototype of a class of relatively simple RNAPs that includes the RNAPs of the related phages T3 and SP6, as well as the mitochondrial RNAPs. The T7 enzyme has been crystallized, and recent genetic and biochemical analyses have facilitated an interpretation of this structure. A growing body of evidence suggests that the phage-like RNAPs are related to other nucleotide polymerases such as DNA polymerases, RNA-dependent RNA polymerases, and reverse transcriptases. In this work, we review information concerning the structure and function of T7 RNAP, and evidence in support of its assignment to a broader class of nucleotide polymerases.
Using Bloom's taxonomy to code verbal protocols of students solving a data structure problem

We describe a preliminary study exploring how computer science students solve a problem in an attempt to understand differences between the successful and the unsuccessful problem solver. Students followed a verbal protocol as they solved a data structures problem, and we analyzed the transcripts of these problem-solving sessions, classifying the statements students made using the revised Bloom's taxonomy. Based on our analysis in this case study, we conclude that the successful problem solver seems to move more frequently from one type of cognitive process to another than the unsuccessful problem solver. For the particular data structure problem the students attempted to solve, we observed that all problem solvers, successful or unsuccessful, tend to follow patterns in their problem-solving process.
Induction of long-term depression and rebound potentiation by inositol trisphosphate in cerebellar Purkinje neurons.

Cerebellar Purkinje neurons receive two major excitatory inputs, the climbing fibers (CFs) and parallel fibers (PFs). Simultaneous, repeated activation of CFs and PFs results in the long-term depression (LTD) of the amplitude of PF-evoked synaptic currents. To induce LTD, activation of CFs may be substituted with depolarization of the Purkinje neuron to turn on voltage-activated calcium channels and increase the intracellular calcium concentration. The role of PFs in the induction of LTD, however, is less clear. PFs activate glutamate metabotropic receptors that increase phosphoinositide turnover and elevate cytosolic inositol 1,4,5-trisphosphate (InsP3). It has been proposed that calcium release from intracellular stores via InsP3 receptors may be important in the induction of LTD. We studied the role of InsP3 in the induction of LTD by photolytic release of InsP3 from its biologically inactive “caged” precursor in voltage-clamped Purkinje neurons in acutely prepared cerebellar slices. We find that InsP3-evoked calcium release is as effective in LTD induction as activation of PFs. InsP3-induced LTD was prevented by calcium chelator 1,2-bis(2-amino phenoxy)ethane-N,N,N′,N′-tetraacetic acid. LTD produced either by repeated activation of PFs combined with depolarization (PF+ΔV), or by InsP3 combined with depolarization (InsP3+ΔV) saturated at ≈50%. Maximal LTD induced by PF+ΔV could not be further increased by InsP3+ΔV and vice versa, which suggests that both protocols for induction of LTD share a common path. In addition to inducing LTD, photo-release of InsP3+ΔV resulted in the rebound potentiation of inhibitory synaptic currents. In the presence of heparin, an InsP3 receptor antagonist, repeated activation of PF+ΔV failed to induce LTD, suggesting that InsP3 receptors play an important role in LTD induction under physiological conditions.
Correlations along a Line in the Two-Dimensional Ising Model

The $2n$-spin correlation function for the two-dimensional Ising model at $T={T}_{c}$ is evaluated for the special case in which all the spins lie along a straight line, separated by many lattice constants. The resulting $2n$-spin function is simply a quotient of products of two-spin correlations. A hypothesis of reducibility of fluctuations in the critical state is introduced. This hypothesis asserts that the product of any two local fluctuating quantities in the same neighborhood of space may be effectively replaced by a finite sum of local fluctuating quantities in this neighborhood. As a result, the previously found form for the $2n$-spin function may be used to evaluate the correlation function of $n$ energy densities when all $n$ points lie on a line. The $n$-energy correlation function is simply a sum of products of two-energy correlations. The quotient form for the spin correlation plus scaling is shown to immediately imply the logarithmic specific heat.
Size-Dependent Reactivity of Magnetite Nanoparticles: A Field-Laboratory Comparison

Logistic challenges make direct comparisons between laboratory- and field-based investigations into the size-dependent reactivity of nanomaterials difficult. This investigation sought to compare the size-dependent reactivity of nanoparticles in a field setting to a laboratory analog using the specific example of magnetite dissolution. Synthetic magnetite nanoparticles of three size intervals, ∼6 nm, ∼44 nm, and ∼90 nm were emplaced in the subsurface of the USGS research site at the Norman Landfill for up to 30 days using custom-made subsurface nanoparticle holders. Laboratory analog dissolution experiments were conducted using synthetic groundwater. Reaction products were analyzed via TEM and SEM and compared to initial particle characterizations. Field results indicated that an organic coating developed on the particle surfaces largely inhibiting reactivity. Limited dissolution occurred, with the amount of dissolution decreasing as particle size decreased. Conversely, the laboratory analogs without organ...
Distinct sequence determinants direct intracellular sorting and modification of a yeast vacuolar protease

We have mapped a sequence determinant in the vacuolar glycoprotein carboxypeptidase Y (CPY) that directs intracellular sorting of this enzyme. Through the study of hybrid proteins, consisting of amino-terminal segments of CPY fused to the secretory enzyme invertase, we have found that the N-terminal 50 amino acids of CPY are sufficient to direct delivery of a CPY-Inv hybrid protein to the yeast vacuole. Our data suggest that this 50 amino acid segment of CPY contains two distinct functional domains; an N-terminal signal peptide followed by a segment of 30 amino acids that contains the vacuolar sorting signal. Deletion of this putative vacuole sorting signal from an otherwise wild-type CPY protein leads to missorting of CPY. Furthermore, examination of the Asn-linked oligosaccharides present on CPY and CPY-Inv hybrid proteins suggests that an additional determinant in CPY specifies the extent to which these proteins are glycosylated in the Golgi complex.