cssi/SciSciGPT-SciSciNet huggingface dataset:
What Motivates Students to Study Enterprise Systems? A Social Cognitive Perspective

Over the past three decades companies of all sizes have been implementing Enterprise Systems (ES). The inherent appeal of ES has not gone unnoticed in the business curriculum either. Several business schools have made systematic changes across their curricula to ensure that they graduate students with an integrated understanding of cross-functional business processes and ES. An ES education can provide significant benefits to students as well as to their potential employers. Yet, there is a lack of research that investigates what motivates students to take ES courses. Therefore, leveraging Social Cognitive Career Theory, this study examines the factors that influence students’ decisions to enroll in ES courses. The findings suggest that domain specific self-efficacy, outcome expectations, and interest in ES courses independently and cumulatively shape students’ aspirations to take ES courses. The paper concludes with a discussion of the findings, implications, limitations, and directions for future research.
Trade, Inequality, and the Political Economy of Institutions

We analyze the relationship between international trade and the quality of economic institutions, such as contract enforcement, rule of law, or property rights. The literature on institutions has argued, both empirically and theoretically, that larger firms care less about good institutions and that higher inequality leads to worse institutions. Recent literature on international trade enables us to analyze economies with heterogeneous firms, and argues that trade opening leads to a reallocation of production in which largest firms grow larger, while small firms become smaller or disappear. Combining these two strands of literature, we build a model that has two key features. First, preferences over institutional quality differ across firms and depend on firm size. Second, institutional quality is endogenously determined in a political economy framework. We show that trade opening can worsen institutions when it increases the political power of a small elite of large exporters, that prefer to maintain bad institutions. The detrimental effect of trade on institutions is most likely to occur when a small country captures a sufficiently large share of world exports in sectors characterized by economic profits.
p53 protein expression in ulcerative colitis-associated colorectal dysplasia and carcinoma

The frequency and timing of p53 inactivation in ulcerative colitis (UC)-associated tumorigenesis were investigated using immunohistochemistry (IHC) to detect p53 protein overexpression in 56 carcinomas and 40 dysplastic epithelia derived from 58 patients with UC undergoing colectomy for neoplasia. p53 DNA in 25 of the carcinomas also was evaluated by single-strand conformation polymorphism analysis (SSCP) to detect point mutations in exons 5-8 and by loss of heterozygosity analysis to detect allelic deletions. Point mutations were detected in 20 of the 25 carcinomas (80.0%) undergoing both IHC and DNA analysis. One carcinoma contained an allelic deletion but no mutations of the corresponding allele within the region tested. p53 overexpression occurred in 16 (76.2%) of the 21 carcinomas with point mutations and/or allelic deletions but not in any of those with wild type DNA. Of the 56 carcinomas evaluated by IHC, p53 overexpression occurred in 34 carcinomas (60.7%). The proportion of positive tumors was independent of stage, anatomic location, differentiation, and histological subtype. Overexpression was observed in nine of 20 dysplastic masses devoid of and situated remote from carcinoma (45.0%) and correlated positively with increasing grade of dysplasia (P < .025). In contrast, overexpression occurred in 16 of 20 dysplastic epithelia situated adjacent to carcinoma (80.0%) and correlated with overexpression by the corresponding carcinomas but not with the grade of dysplasia present (P = .013). It is concluded that p53 overexpression can be detected by IHC in most, although not all, UC-associated carcinomas with p53 mutations and/or allelic deletions. Based on this method, p53 overexpression occurs frequently in UC-associated carcinomas regardless of stage and pathological characteristics, in noncancerous dysplastic masses with high grade dysplasia, and in dysplasias of all grades situated adjacent to carcinomas. These findings implicate p53 inactivation in the progression from dysplasia to carcinoma in UC and suggest that its occurrence in dysplastic epithelium may be an independent marker of malignant potential.
Fate of viruses during wastewater sludge treatment processes

Infectious viruses are shed from humans by many routes. These include coughing and sneezing, contact with and aerosolization from external body lesions, urinary and intestinal excretions. Viruses shed by the latter two routes, urinary and intestinal excretions, are likely to be present as contaminants in domestic wastewater. The purpose of this review is to summarize recent information on the pathways which viruses follow during wastewater sludge‐generation processes and to examine information pertinent to the fate of viruses during wastewater sludge disposal. Information is included on viruses capable of causing human illness, as well as on bacterial viruses also present in wastewater, which, in some ways, may serve as indicators when assessing the likely fate of human viruses.
Powder-Solution-Composite Technique for Measuring Electrical Conductivity of Ceramic Powders

A method for measuring the conductivity of ceramic powders has been developed using effective medium theory and impedance spectroscopy. Powders to be tested are mixed with aqueous solutions of varying NaCI concentrations to form a composite slurry. The impedance response of these powder-solution-composites (PSCs) is measured and analyzed using composite equivalent circuit and effective medium theories. Values obtained for a test powder of copper aluminate (CuAlO 2 ) match closely to four-point dc values measured on bulk sintered bars. A comparison was also made in a system with highly composition-dependent conductivity (YITO, In 2-2x-2y Y 2x Sn 2y O 3 , 0.08 ≤ x ≤ 0.20) to evaluate the upper and lower bounds for accurate measurements. Results from the PSC method matched the sintered bar four-point dc values within the range of NaCI solutions employed (0.5-10 -4 S/cm).
ENDOGENOUS RENAL TRANSPORT OF FREE AMINO ACIDS IN CHILDREN WITH IDIOPATHIC NEPHROTIC SYNDROME (INS)

Endogenous renal transport of free amino acids was determined in 28 patients with INS aged 3-17 years. GFR measured concomittantly by inulin was 117.3 ml/min/1.73 m2. Values of the serum concentrations, urinary excretion, renal clearance rates, net tubular reabsorption and percentage tubular reabsorption of 19 amino acids were determined by ion exchange chromatography. The results were compared with values of 12 healthy children without renal disease between the age of 2-13 years (Brodehl,J.,K.Gellissen,Pediatrics 42:395,1968). The serum values of aspartic acid, serine, cystine, tyrosine, ornithine and lysine were significantly higher and the values of phenylalanine and histidine lower in INS as compared to healthy children. The urinary excretion of isoleucine was higher, the excretion of methionine and histidine and the clearance rates of histidine and cystine were lower in INS. The net tubular reabsorption of proline, phenylalanine and histidine were significantly lower in INS. But the percentage tubular reabsorption of all amino acids did not differ significantly. During relapse and under the influence of corticosteroids percentage tubular reabsorption was lower.
The Role of the Pediatric Pathologist as Expert Witness in a Case of Neonatal Death

The pediatric pathology literature has given scant attention to expert testimony by physicians in medical malpractice actions that involve infants and children. We report the case of a neonate who died after a brief clinical course characterized by intermittent respiratory distress. The prosecting pathologist's erroneous postmortem diagnoses prompted the infant's mother to sue the attending physician for malpractice. During the course of the litigation, it became clear that the pathologist's testimony was evasive and misleading. After deliberating briefly, the jury ruled in favor of the defendant. Had the plaintiff's attorney obtained a 2nd opinion from another pathologist, preferably a pediatric pathologist, the legal proceedings in this case may have been avoided, thereby averting needless distress for both the plaintiff and defendant, aside from the costs involved. We discuss U.S. Supreme Court rulings pertaining to medical expert testimony and identify remedies to increase just outcomes in cases of medical malpractice.
Evaluation of Ionic Mobilities by Coupling the Scattering on Atoms and on Electron Density

A recently developed method to calculate gas-phase mobilities by scattering on electron density isosurfaces (SEDI) has been applied to carbon cluster ions. The investigation has covered species belonging to all major structural families identified in drift tube studies (chains, monocyclic and bicyclic rings, graphite sheets, and fullerenes). Relative cross sections of Cn- and Cn+ predicted by SEDI are in excellent agreement with the measurements across a wide range of cluster sizes and shapes. However, absolute values could not be fit for either charge state. This happens because SEDI ignores the long-range ion−buffer gas interaction known to be important for many systems including carbon clusters. To overcome this problem, we propose a new technique to evaluate mobilities by coupling SEDI with trajectory calculations. This approach allows one to introduce the repulsive interaction accurately and still account for the attractive part of the potential. This hybrid SEDI−TC treatment has been found substanti...
The Compass Rose Effectiveness Model

The effectiveness model focuses the institution on mission achievement through assessment and improvement planning. Eleven mission criteria, measured by key performance indicators, are aligned with the accountability interest of internal and external stakeholders. A Web-based performance assessment application supports the model, documenting the impact of strategic planning on continuous improvement.
Trends in Anterior Cruciate Ligament Reconstruction in the United States.

Background:The anterior cruciate ligament (ACL) is the most frequently injured ligament in the knee for which surgery is performed. United States national estimates of ACL reconstruction vary widel...
Boltzmann diffusive limit beyond the navier-stokes approximation

Given a normalized Maxwellian μ and n ≥ 1, we establish the global-in-time validity of a diffusive expansion (0.1) F e (t,x,v)=μ+√μ{ef 1 (t,x,v)+e 2 f 2 (t,x,v)+···+e n f e n (t,x,v)}. for a solution F e to the rescaled Boltzmann equation (diffusive scaling) (0.2) e∂ 1 F e +v·∇ x Fe=1 eQ(F e ,F e ) inside a periodic box T 3 . We assume that in the initial expansion (0.1) at t = 0, the fluid parts of these f m (0,x,v) have arbitrary divergence-free velocity fields as well as temperature fields for all 1 ≤ m ≤ n while f 1 (0,x,v) has small amplitude in H 2 . For m ≥ 2, these f m (t,x,v) are determined by a sequence of linear Navier-Stokes-Fourier systems iteratively. More importantly, the remainder f e n (t,x,v) is proven to decay in time uniformly in e via a unified nonlinear energy method. In particular, our results lead to an error estimate for f 1 (t,x,v), the well-known Navier-Stokes-Fourier approximation, and beyond. The collision kernel Q includes hard-sphere, the cutoff inverse-power, as well as the Coulomb interactions.
Summing the vertex angles of stars

Determining the sum of the vertex angles of a 5‐pointed star was not obvious to many who were queried. This serves as stimulus to offer several surprisingly simple solutions and then to characterize how many different vertex sums are possible for certain types of n‐pointed stars. Interesting classes of stars considered include those formed by extending the sides of a convex n‐gon, and those formed by joining every 8th point of npoints that form a convex n‐gon. Perhaps, most surprising, are the transformations‐‐via sequences of vertex movements none of which changes the star's vertex sum—by which stars can be deformed without changing their vertex sums. Further investigations are also suggested. The geometrical flavour and intuitive physical approaches taken provide appealing, challenging problems to attempt and explore further.
SU-FF-T-381: Optimization of Radiotherapy Dose-Time-Fractionation Scheme with Consideration of Tumor Specific Biology

Purpose: To explore the influence of the “four Rs” of radiobiology on external beam radiotherapeutic strategies for fast and slowly proliferating tumors and develop an optimization framework for tumor-biology specific dose-time-fractionation scheme. Method and Materials: The LQR model proposed by Brenner et al (IJROBP, 32(2), 1995) is used to describe radiation response of tumor, in which the time dependence of sublethal damage repair and redistribution and reoxygenation effects are included. The optimum radiotherapeutic strategy is defined as the treatment scheme that maximizes tumor biologically effective dose (BED) while keeping normal tissue BED constant. Simulated annealing optimization technique is used to search for the optimal radiotherapeutic strategies and the influences of different model parameters are studied. Results: For fast proliferating tumors the optimum overall time is similar to the kick-off time Tk and almost independent of the interval patterns. Significant increases in tumor control can be obtained using accelerated schemes for the tumors with doubling time shorter than 3 days but little gain for those with doubling time longer than 5 days. Although the incomplete repair of normal tissues has little influence on fractionation doses, when the resensitization effect included, it becomes obvious that the optimum scheme require higher fraction doses at the beginning and end of each treatment week and hyperfractionation schemes have little advantageous. For slowly proliferating tumors, hypofractionation schemes are the optimum schemes and overall time should be larger than a minimum one mainly influenced by the resensitization time. Conclusion: The proposed approach provided a useful tool to systematically optimize radiotherapeutic schemes for different tumors based on the differences in the “four Rs” of radiobiology between tumor and normal tissue. The results suggest that tumor site-specific optimization has great potential to improve therapeutic outcome for both fast and slowly proliferating tumors and provide useful information for designing radiotherapeutic clinical trials.
Structure and internal mobility of proteins: a molecular dynamics study of hen egg white lysozyme.

The structure and internal motions of the protein hen egg white lysozyme are studied by analysis of simulation and experimental data. A molecular dynamics simulation and an energy minimization of the protein in vacuum have been made and the results compared with high-resolution structures and temperature factors of hen egg white lysozyme in two different crystal forms and of the homologous protein human lysozyme. The structures obtained from molecular dynamics and energy minimization have root-mean-square deviations for backbone atoms of 2.3 A and 1.1–1.3 A, respectively, relative to the crystal structures; the different crystal structures have root-mean-square deviations of 0.73–0.81 A for the backbone atoms. In comparing the backbone dihedral angles, the difference between the dynamics and the crystal structure on which it is based is the same as that between any two crystal structures. The internal fluctuations of atomic positions calculated from the molecular dynamics trajectory agree well with the temperature factors from the three structures. Simulation and crystal results both show that there are large motions for residues involved in exposed turns of the backbone chain, relatively smaller motions for residues involved in the middle of helices or β-sheet structures, and relatively small motions of residues near disulfide bridges. Also, both the simulation and crystal data show that side-chain atoms have larger fluctuations than main-chain atoms. Moreover, the regions that have large deviations among the x-ray crystal structures, which indicates flexibility, are found to have large fluctuations in the simulation.
Effect of sodium transport and vasopressin on the oxidation of palmitic acid by the toad bladder

Abstract 1. 1. The object of this investigation was to examine some factors influencing the rate of oxidation of palmitate by the toad bladder, with special reference to the effects of vasopressin and changes in active sodium transport. 2. 2. Palmitic acid is oxidized to CO 3 by the toad bladder. This rate of oxidation is increased when the ratio moles of palmitate/moles of albumin in the incubation medium is higher, and also when glucose is present. 3. 3. Inhibition of active sodium transport, either by using sodium-free media or adding ouabain reduces the rate of palmitate oxidation. 4. 4. Vasopressin increases palmitate oxidation in the presence of sodium, not in its absence.
Length dependence of cutoff wavelength for single‐mode fiber

The effective cutoff wavelength of single-mode fiber cable cannot be completely determined because the bending loss, which prevents propagation of the second-order mode, depends upon the bending distribution of the fiber as well as on the length and index profile of the fiber. By measuring the bending loss of the LPn mode of step-index single-mode fiber, it is found that the effective cutoff wavelength of reel-wound fiber shifts to lower wavelengths along the distance. The length dependence is proved by experiment and agrees well with the theory. The length dependence of the cutoff wavelength of optical cable is estimated by experiment and it is established that the effective cutoff wavelength can be prescribed by the microbending profile and, compared with the value given by the conventional bend method of a 2-m sample, the decrease in effective cutoff wavelength for 1-m cable is estimated as 0.1 um. If this length dependence is used, it can be applied in long-distance systems provided a fiber having longer cutoff wavelength and favorable.bending loss characteristics or low dispersion is used.
Application of a Plasma Reactor to Modify Egg Ovalbumin for Improved Solubility

A plasma reactor was used to change the surface structure of ovalbumin and enhance solubility. The gases used to generate the plasmas were air, argon, nitrogen and oxygen. Ovalbumin was exposed to the gases for 10, 20, 30, 60, and 120 min. Unexposed ovalbumin served as the control. Samples were examined by polyacrylamide gel electrophoresis (PAGE), spectrophotometry, fluorometry, differential scanning calorimetry, and circular dichroism. Solubility and hydrophobicity of ovalbumin increased with exposure time, whereas endothermic enthalpy, onset temperature and peak temperature of ovalbumin decreased. No evidence of protein hydrolysis was observed in PAGE. No change in CD spectra resulted from the plasma treatment. The structural changes were regarded as conformational adaptability.
Diminished calcium homeostasis and increased susceptibility to excitotoxicity of JS 3/16 progenitor cells after differentiation to oligodendroglia

JS 3/16, derived from passaged oligodendroglial cultures prepared from rat cerebral white matter, differentiate from progenitors (OP) into complex process-bearing, galactocerebroside-positive but myelin basic protein-negative immature oligodendrocyte-like cells (ImO) after withdrawal of trophic factors. We found that JS 3/16 ImO are markedly more susceptible than OP to cell death after sustained α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate glutamate receptor (AMPA-GluR) activation. This excitotoxicity is preceded by loss of intracellular Ca2+ homeostasis, which is more marked in ImO than OP. We identified three factors likely to contribute to the diminished Ca2+ homeostatic capacity of ImO. First, signal intensities of immunoreactive GluR2, GluR3, and GluR4 AMPA-GluR subunits are increased 1.3- to 2.2-fold in ImO over OP without comparable changes in RNA editing and alternative splicing. Second, transcriptional levels of genes encoding Na+-Ca2+ exchanger proteins and a plasma membrane ATPase (PMCA1), which are necessary for Ca2+ extrusion across the plasma membrane, are lower in ImO than in OP. Third, ImO have more depolarized basal mitochondrial membrane potential (ΔΨ) than OP, and ΔΨ collapses within 15 min after onset of AMPA-GluR activation in almost all ImO, but not in the majority of OP. This ΔΨ collapse limits the capacity of ImO mitochondria to buffer the rise in intracellular Ca2+ caused by AMPA-GluR activation. The JS 3/16 line provides a valuable system for analysis of intracellular Ca2+ homeostasis and AMPA-GluR-mediated excitotoxicity in the oligodendroglial lineage. GLIA 31:165–180, 2000. © 2000 Wiley-Liss, Inc.
An experimental investigation of the effect of rotation on the rate of unimolecular decomposition of NO2

Abstract The effect of rotational excitation on the rate of unimolecular decomposition has been examined for a benchmark system. NO 2 molecules having specific excitations were selected by pumping rotational components of the (1,0,1) ← (0,0,0) combination band with the output from a 0.02 cm −1 resolution parametric oscillator, and reaction rates were obtained by applying the picosecond-resolution pump-probe technique to these tagged species. The addition of up to 100 cm −1 of rotational energy ( N ⩽ 15, K a = 0), with other parameters held fixed, left the rate unaffected. Implications are discussed within the framework of statistical rate theories.
Effect of long term aging on the microstructural stability and mechanical properties of Ti–6Al–2Cr–2Mo–2Sn–2Zr alloy

Abstract Microstructural development after long term aging and its effect on the mechanical properties have been investigated in Ti–6Al–2Cr–2Mo–2Sn–2Zr alloy. Four types of precipitates have been identified in the alloy, they are α 2 -Ti 3 Al, ω, silicides and α-TiCr 2 Laves phase. α 2 -Ti 3 Al and ω are observed in the as-received materials and all aged samples. Silicides, (Ti, Zr) x Si 3 (5≤ x ≤6), are found in the specimens aged at 550–650 °C over 500 h. The silicides have a hexagonal structure with a lattice parameter: a =7.01±0.03, c =3.63±0.06 A. The orientation relation between the silicides and the parent β-phase has been determined as: [111] β //[0001] silicide , (101) β //(1100) silicide . Laves phase α-(Ti, Zr)Cr 2 is observed in the samples aged at 450–550 °C over 500 h. It has a cubic structure ( a =7.12±0.03 A) with an orientation relationship with the α- and β-Ti matrix: [110] α-TiCr 2 //[0001] α-Ti //[110] β-Ti , ( 1 13) α - TiCr 2 //( 1 100) α - Ti //( 1 10) β - Ti . Long term aging in the temperature range of 450–550 °C results in significant decrease of fracture toughness and increase of intergranular failure, due to precipitation of α 2 -Ti 3 Al and α-(Ti, Zr)Cr 2 Laves phase. No considerable change in fracture toughness for the samples aged at 650 °C up to 1000 h is found in spite of precipitation of the α 2 -Ti 3 Al and the silicides. The retention of fracture toughness after aging at these temperatures has been attributed to coarsening of secondary α-Ti platelets during the aging treatment.
Ability to Induce Atrial Fibrillation in the Peri-operative Period Is Associated with Phosphorylation-dependent Inhibition of TWIK Protein-related Acid-sensitive Potassium Channel 1 (TASK-1)

Peri-operative atrial fibrillation (peri-op AF) is a common complication following thoracic surgery. This arrhythmia is thought to be triggered by an inflammatory response and can be reproduced in various animal models. Previous work has shown that the lipid inflammatory mediator, platelet-activating factor (PAF), synthesized by activated neutrophils, can induce atrial and ventricular arrhythmias as well as repolarization abnormalities in isolated ventricular myocytes. We have previously shown that carbamylated PAF-induced repolarization abnormalities result from the protein kinase C (PKC) e-dependent phosphorylation of the two-pore domain potassium channel TASK-1. We now demonstrate that canine peri-op AF is associated with the phosphorylation-dependent loss of TASK-1 current. Further studies identified threonine 383 in the C terminus of human and canine TASK-1 as the phosphorylation site required for PAF-dependent inhibition of the channel. Using a novel phosphorylation site-specific antibody targeting the phosphorylated channel, we have determined that peri-op AF is associated with the loss of TASK-1 current and increased phosphorylation of TASK-1 at this site.
Computational and behavioral investigations of lexically induced delays in phoneme recognition

Previous studies have failed to demonstrate lexically induced delays in phoneme recognition, casting doubt on interactive models of speech perception. We present TRACE simulations that explain these failures: previously tested conditions failed to produce lexically induced delay effects because the input was too unambiguous and the control condition was conflated with lexical status and neighborhood structure. Since between-layer connections are solely excitatory, between-layer delay effects can emerge only indirectly through facilitation of within-layer competition. If the lexically consistent phoneme partially matches the input acoustics, it will become partially active. Additional support from lexical feedback will extend the duration of competition between the acoustically present phoneme and the lexically consistent phoneme, thus delaying detection. This prediction holds across a range of relevant parameter values. Two behavioral experiments tested and confirmed this prediction. These results answer one of the challenges to the interactive view of speech perception.
The Influence of Economists On the Federal Reserve Act

Many economists helped to lay the groundwork for the Federal Reserve. Some did important work analyzing the problems of the National Bank System and arguing for formation of a central bank in economics journals. At least as importantly, if not more so, some economists took an active role in the reform movement and provided help and advice with the actual Congressional bill. Among these are J. Lawrence Laughlin, who chaired a group that actively raised support for the Federal Reserve Act in Congressional districts, and H. Parker Willis, who served as an expert for the subcommittee which wrote the original draft of what became the Federal Reserve Act. More broadly, this episode illustrates the impact that intellectuals and ideas can have on actual events; the analysis contemporary economists did in academic journals and in more political activities before and after the panic of 1907 guided the actual formation of a working central bank (JEL B10, N21).
Use the Purpose by Which All May Benefit: The Semiotics of ‘Public Use’

This paper applies semiotic analysis to issues arising from the recent Supreme Court decision of Kelo v. City of New London [545 U.S.469] (2005). The author uses the tools of semiotics to explore the evolution of language and speech and their relationship to the terms, “private property” and “public use” as used by the Supreme Court and the general public in the years leading up to the Kelo decision. This paper will first provide an overview of the field of semiotics, describing the prevailing thought and the methods utilized by semioticians to find meaning. Second, the tools of semiotics will be applied to Supreme Court cases, beginning with Bauman v. Ross [167 U.S. 548] (1897) and continuing to Kelo v. City of New London. Utilizing these tools, the author will show how, within the span of approximately 100 years, the speech of the court has affected the language of legal discourse. The signs to which both Bauman and Kelo seek to attach meaning are found in the Fifth Amendment to the US Constitution, which provides, in relevant part, “…nor shall private property be taken for public use, without just compensation.”(emphasis added) (U.S. Const. Amendment 5). This dialectic activity resulted in the development of two different languages. One was used by the layperson, whereas the other was found in relevant legal/political institutions such as the US Supreme Court. This paper will focus on the fundamental change in the meaning of the sign/expression “public use.”
Determination of Stability and Control Derivatives using Computational Fluid Dynamics and Automatic Differentiation

With the recent interest in novel control effectors there is a need to determine the stability and control derivatives of new aircraft configurations early in the design process. These derivatives are central to most control law design methods and would allow the determination of closed-loop control performance of the vehicle. Early determination of the static and dynamic behavior of an aircraft may permit significant improvement in configuration weight, cost, stealth, and performance through multidisciplinary design. The classical method of determining static stability and control derivatives - constructing and testing wind tunnel models - is expensive and requires a long lead time for the resultant data. Wind tunnel tests are also limited to the preselected control effectors of the model. To overcome these shortcomings, computational fluid dynamics (CFD) solvers are augmented via automatic differentiation, to directly calculate the stability and control derivatives. The CFD forces and moments are differentiated with respect to angle of attack, angle of sideslip, and aircraft shape parameters to form these derivatives. A subset of static stability and control derivatives of a tailless aircraft concept have been computed by two differentiated inviscid CFD codes and verified for accuracy with central finite-difference approximations and favorable comparisons to a simulation database.
Delayed presentation of traumatic intraperitoneal bladder rupture

A child with urine ascites as a delayed manifestation of post-traumatic intraperitoneal bladder rupture is presented. The diagnosis was suggested by abdominal CT scan and confirmed with a cystogram. While uncommon, late presentation of intraperitoneal bladder rupture following trauma may occur from masking of a primary laceration or development of secondary rupture at the site of a hematoma in the bladder wall. Since CT may be a primary diagnostic study performed following abdominal trauma, the radiologist should be aware of CT findings suggesting bladder rupture and of the possibility of delayed presentation of this injury.
Connexin32 gap junction channels in stably transfected cells. Equilibrium and kinetic properties

Communication-deficient cells (the SKHep1 cell line) were stably transfected with a plasmid containing cDNA which encodes the major gap junction protein of rat liver, connexin32. Application of the dual whole-cell voltage clamp technique with patch electrodes to pairs of transfected SKHep1 cells revealed strong sensitivity of junctional conductance (gj) to transjunctional voltages (Vjs) of either polarity, with the ratio of minimal to maximal gj (gmin/gmax) being approximately 0.1 at the highest Vjs. Steady-state gj values as a function of voltages of either polarity were well fit by the Boltzmann equation. V0, the voltage at which gj was reduced by 50%, was approximately 25-30 mV; A, the Boltzmann parameter describing voltage dependence, was approximately 0.06 (corresponding to an energy difference between states of approximately 1 kCal/mol and to approximately 2 gating charges moving through the field). The kinetics of the transjunctional voltage dependence were slow (tau greater than 5 s at 20-40 mV, tau = 2 s at and beyond 70 mV). Voltage sensitivity of the opening rate constant (alpha) was approximately 30% lower than that of the closing rate constant (beta) over the Vj range 0-70 mV; at higher voltages, voltage sensitivity of alpha and beta saturated. The kinetic response of gj to a paradigm in which gj was first rendered low by a prepulse of opposite polarity indicated that the voltage sensors are likely to be arranged in series. Transitions between open and closed states in response to transjunctional voltages of either polarity are single order processes; transitions from one closed state to the other involve passage through the open state.
USA ABORTS INTERNATIONAL FAMILY PLANNING

The US Agency for International Development (USAID) has been a leader in international family planning for almost 30 years accounting for 46% of all funds in international family planning provided by OECD countries during 1991. Moreover relative to other donor countries the US supplies worldwide a disproportionate amount of contraceptives. While international family planning activities received $546 million in 1995 the budget was slashed in 1996 to $72 million. This unprecedented cut will have a profound effect upon the reproductive health and family planning choices of tens of millions of people in developing countries. Millions of additional unintended pregnancies and maternal and child deaths may result. 1996 began with the White House and Congress in political gridlock with negotiations on foreign aid stalled on the issue of abortion. The Republican-led House of Representatives wanted to bar support of any nongovernmental organization (NGO) which also provided information on abortion while Democratic President Bill Clinton affirmed that he would veto such legislation. At the end of January the House passed the Balanced Budget and Down Payment Act (HR 2880) containing clauses which cut the aid budget by 35% and barring new money in the area of family planning until July 1. Spending was limited to the allocation of 6.5% of the total budget each month. Some social marketing programmers who distribute condoms and oral contraceptives are already feeling the pinch and some programs will simply run out of contraceptives. This cut in funding also bodes ill for achieving the goals of the 1994 International Conference on Population and Development. There is however hope that the cuts will be reversed for the next fiscal year. The author notes survey findings which indicate that US citizens support higher budgets for family planning.
Assay of serum vitamin B12 concentration using Co57-B12 and intrinsic factor.

SummaryBased on some observed properties of the B12-I.F. complex, an assay procedure is described for determining serum Vit. B12 levels using isotopically labeled Vit. B12 and intrinsic factor. 83%-112% of crystalline Vit. B12 added to serum was recovered in the assay. Concentrations of Vit. B12 in normal, B12 deficient, and leukemic sera were in the ranges, 104-328 μμg/ml, 0-72 μμg/ml and over 1000 μμg/ml respectively.
Inefficiency of the use of Boolean functions for information retrieval systems

In this note we attempt to point out why boolean functions are, in general, not applicable in information retrieval systems.
Streaming potentials of nonuniformly charged surfaces

Abstract The general equations for the streaming potential are solved numerically for a system in which the surfaces of a slit are nonuniformly charged. Specifically, patches of varying surface charge are periodic in the direction of the applied pressure drop. Introduction of the nonuniform charge produces distortions in the equilibrium electrostatic field. This distortion in the electrostatic potential can alter the value of the zeta potential from its expected value. In fact, under conditions of moderate surface charge and ionic strength, the value of the zeta potential is over 30% higher than expected. The characteristic symptom of field distortion is the generation of velocities normal to the charged surface. We describe the physics which gives rise to the normal velocities and identify the dimensionless properties of the streaming-potential system which influence the magnitude of these velocities and influence the value of the zeta potential. As the exact solution of the equations for this streaming-potential system is computationally intensive, a regular, first-order-perturbation solution is also developed. The perturbation solution tests the limits of the popular assumption that the total electric potential is simply the sum of the equilibrium potential and the applied potential.
Carl Gegenbaur Versus Anton Dohrn

Both Carl Gegenbaur and Ernst Haeckel feuded with Anton Dohrn with respect to vertebrate origins and how one should study phylogeny. Although they argued about methodology, and also had serious differences with respect to philosophical issues, their different personal agendas with respect to research and institution-building may have been equally significant.
The Effects of Differential Digestion Rates of Zooplankton by Alewife, Alosa pseudoharengus, on Determinations of Selective Feeding

Abstract Ivlev's electivity index (E) was used to assess selective feeding by the alewife (Alosa pseudoharengus) on crustacean zooplankton in southern Green Bay, Lake Michigan. Alewives positively selected larger species of Copepoda, especially Mesocyclops edax. Alewives appeared to negatively select all Cladocera. However, field data from Lake Michigan and other lakes containing abundant populations of alewives indicate positive selection may be occurring on Daphnia. Positive selection of Daphnia by alewives probably took place in southern Green Bay, although this was not indicated in electivity indices. Laboratory studies revealed that Daphnia were digested most rapidly by alewives and, therefore, were under-represented in stomach contents relative to other planktonic species. Consequently, it is suggested that differential digestion rates of prey organisms may also occur in alimentary tracts of other fish species. This could have an effect on interpretation of selective feeding data using Ivlev's elect...
Pharmacology of Vitamin C

A better understanding of the functions of ascorbic acid would help clarify the magnitude of the influence of this vitamin on health-related conditions. Many of the purported benefits require confirmation as well as a knowledge of the mechanism of action. The majority of investigations of the association of vitamin C with various types of cancer, with cardiovascular risk, and with cataract formation were epidemiologic studies. Often it was not possible to discern whether the apparent protective effect was due to vitamin C, vitamin E, or carotene, or to a combined effect of these nutrients or of additional factors. Human intervention trials may provide definitive and quantitative assessments of the role of vitamin C in health maintenance. We need to gain a more thorough understanding of the interactions of vitamin C with other nutrients, such as vitamin E and carotenoids, in order to appreciate the role of vitamin C in disease prevention. Investigators are increasingly recognizing the diverse functions of vitamin C in the body in addition to its role in collagen synthesis. However, the functional consequences of these many important roles of vitamin C remain essentially unknown. Excluding scurvy, the health consequences of inadequate vitamin C status are not well characterized. Nonetheless, epidemiologic evidence suggests a role for vitamin C in cancer and heart disease as well as in a number of other diseases.
Asymmetry of training effects in nonspecific transfer of training

Three groups of 16 pigeons each were given true discrimination (TD), nondifferential (ND), or single-stimulus (SS) training with line angles, and later were tested for the acquisition of a brightness discrimination. Half of the subjects were tested on the brightness problem immediately after line-angle training; the other half were tested with a wavelength discrimination problem first, then were returned to their original line-angle training regimen, and finally were tested on the brightness problem. Performance on the brightness problem was uninfluenced by experience with a prior wavelength problem. The TD subjects showed both more rapid acquisition and a higher level of asymptotic performance than the SS and ND groups, which did not differ. The TD facilitation effect was due to more rapid extinction of responding to S–. It was argued that failure to obtain an ND retardation effect may be due to the high degree of similarity between training stimuli used in Stage 1 and/or to a test bias against finding ND effects.
Dual Role of Wingless Signaling in Stem-like Hematopoietic Precursor Maintenance in Drosophila

In Drosophila, blood development occurs in a specialized larval hematopoietic organ, the lymph gland (LG), within which stem-like hemocyte precursors or prohemocytes differentiate to multiple blood cell types. Here we show that components of the Wingless (Wg) signaling pathway are expressed in prohemocytes. Loss- and gain-of-function analysis indicates that canonical Wg signaling is required for maintenance of prohemocytes and negatively regulates their differentiation. Wg signals locally in a short-range fashion within different compartments of the LG. In addition, Wg signaling positively regulates the proliferation and maintenance of cells that function as a hematopoietic niche in Drosophila, the posterior signaling center (PSC), and in the proliferation of crystal cells. Our studies reveal a conserved function of Wg signaling in the maintenance of stem-like blood progenitors and reveal an involvement of this pathway in the regulation of hemocyte differentiation through its action in the hematopoietic niche.
Changing kinetic properties of the two-enzyme phosphoglycerate kinase/NADP-linked glyceraldehyde-3-phosphate dehydrogenase couple from pea chloroplasts during photosynthetic induction

The kinetics of the two enzyme phosphoglycerate kinase (EC 2.7.2.3)/NADP-linked glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.13) couple are negatively cooperative and will also fit a model for two enzymes acting on one substrate. When the chloroplast is illuminated apparent negative cooperativity is reduced; maximal velocity of only one of the two enzymes in the two-enzyme model is increased. Even after light activation the activity of glyceraldehyde-3-phosphate dehydrogenase appears to be too low to support photosynthesis at calculated levels of glycerate-1,3-bisphosphate in isolated chloroplasts (Marques, I.A., Ford, D.M., Muschinek, G. and Anderson, L.E. (1987) Arch. Biochem. Biophys. 252, 458–466). The activity of the coupled reaction is apparently sufficient to support observed rates of CO2 fixation, which suggests that glycerate-1,3-bisphosphate may be channeled from the kinase to the dehydrogenase in vivo.
COMMUNITY STRUCTURE DYNAMICS OF EPILITHIC AND EPIPHYTIC DIATOMS IN A MISSISSIPPI STREAM1

Epilithic and epiphytic diatoms were collected monthly from 18 June 1979 through 19 May 1980 from both shaded and unshaded sites of Sessums Creek, a shallow, oligotrophic and strongly alkaline stream in northeastern Mississippi. The dominant macroalgae were filamentous green algae belonging to the non-mucilage producing genera Cladophora and Rhizoclonium. Ninety taxa were identified with Navicula minima Grun. and Nitzschia dissipata (Kutz.) Grun. accounting for 50% of all valves counted. Other important taxa were Navicula menisculus var. upsaliensis (Grun.) Grun., N. cryptocephala var. veneta (Kutz.) Rabh., Achnanthes minutissima Kutz. and Cymbella turgida (Greg.) Cl. With few exceptions, the more dominant taxa were equally abundant in the shaded and unshaded sites and also in the epilithon and epiphyton. Species diversity (H') and the number of taxa in a sample in all four habitats showed an identical pattern, being lowest in winter and highest in fall. No one pair of habitats was more structurally similar than any-other pair when compared by a similarity index (SIMI). Apparently, differences in light intensity and substrate type had little effect on diatom distribution in Sessums Creek and it was concluded that the locality sampled supported a single, nearly homogeneous diatom community.
Habitat Partitioning and Niche Overlap of Two Forest Thrushes in the Southern Appalachian Spruce—Fir Forests

Abstract. Guilds of species that share ecological similarities or recent ancestors are often the basis of studies concerning habitat partitioning. An interesting result of many of these studies is that means of partitioning in one area of sympatry may be different from those in disjunct areas of overlap. Here, we quantified the differences in habitat preference of two forest thrushes in the southern Appalachian Mountains. The Hermit Thrush (Catharus guttatus) has recently expanded its breeding range south along the spine of the Appalachians into the spruce—fir forests of Virginia, North Carolina, and Tennessee. There, it shares breeding habitat with the congeneric Veery (C. fuscescens), previously the only forest thrush breeding in this area. We used several multivariate analyses of habitat variables within both species' territories to understand how these species partition the available habitat and to test if these means of partitioning are similar to those found by other studies. We calculated the niche...
INFORMATION, THE DUAL ECONOMY, AND DEVELOPMENT

We examine the interactions between different institutional arrangements in a general equilibrium model of a modernizing economy. There is a modern sector, where productivity is high but information asymmetries are large, and a traditional sector where productivity is low but information asymmetries are small. Consequently, agency costs in the modern sector make consumption lending difficult, while such lending is readily done in the traditional sector. The resulting trade-off between credit availability and productivity implies that not everyone will move to the modern sector. In fact, the laissez-faire level of modernization may fail to maximize net social surplus. This situation may also hold in the long run: in a dynamic version of the model, a "trickle-down" effect links the process of modernization with reduction in modern sector agency costs. This effect may be too weak and the economy may get stuck in a trap and never fully modernize. The two-sector structure also yields a natural theoretical testing ground for the Kuznets inverted-U hypothesis: we show that even within the "sectoral shifting" class of models, this phenomenon is not robust to small changes in model specification.
PATELLOFEMORAL PAIN SYNDROME IN THE FEMALE ATHLETE

Although PFS will continue to be a therapeutic challenge, the prognosis for most female athletes is good, especially if they are motivated and compliant with their treatment program. Particularly in women, care should be taken to avoid placing too much emphasis on biomechanical variants that may not be clinically significant or correctable because such findings can reinforce a feeling that "nothing can be done." In many cases, muscle dysfunction and repetitive loading of the patellofemoral joint rather than fixed biomechanical factors contribute to the development of PFS. Nonetheless, the importance of a detailed biomechanical assessment on physical examination must not be neglected, particularly in athletes who are not improving with conservative treatment and who may become surgical candidates. A practical initial treatment program for most athletes with nontraumatic PFS begins with relative rest, quadriceps strengthening, and stretching of tight myotendinous units. The introduction of NSAIDs, orthoses, taping, knee sleeves, and more specific rehabilitative exercises should be an individualized decision based on physical findings, past treatment results, and athletic expectations. Surgical referral should be considered in cases of PFS or patellar instability refractory to prolonged maximal nonoperative treatment.
The algebraic structure of linearly recursive sequences under hadamard product

We describe the algebraic structure of linearly recursive sequences under the Hadamard (point-wise) product. We characterize the invertible elements and the zero divisors. Our methods use the Hopf-algebraic structure of this algebra and classical results on Hopf algebras. We show that our criterion for invertibility is effective if one knows a linearly recursive relation for a sequence and certain information about finitely-generated subgroups of the multiplicitive group of the field.