cssi/SciSciGPT-SciSciNet huggingface dataset:
Predicting properties of composite materials

Composite materials offer significant advantages over conventional materials in certain automotive applications. For example, metal-matrix composite of SiC particles in Al can be used to reduce the weight of connecting rods and pistons, while maintaining the required strength, resulting in improved fuel economy. Polymer composite with glass fibers may offer advantageous substitutes for various automobile parts and is an ongoing research activity in the automotive industry. The potential widespread use of a variety of composites has focused attention on predicting their mechanical properties from a knowledge of the constituents’ properties. What one would actually like to predict is the average of the constituents’ moduli; these are called effective moduli of the medium.
Cognitive Dissonance Theory

The theory of cognitive dissonance and its major experimental paradigms are described in this article. When an individual holds two or more elements of knowledge that are relevant to each other but inconsistent with one another, a state of discomfort or dissonance is created. Organisms are motivated by the state of dissonance and they may engage in ‘psychological work’ to reduce the inconsistency. Revisions to the original theory and their supporting research are then described. The major theoretical revisions differ primarily in terms of the motivation they posit for causing dissonance reduction. The revisions are self-consistency, self-affirmation, new look, and action-based model.
A Variety of Solutions to the Yang-Baxter Equation

The purpose of this note is to give a complete description of all invertible solutions of the Yang-Baxter equations on \(V \otimes V \) that are of the formσ+ Pwhere a is the flip andPis a rank one tarnsformation. The main result is that the corresponding variety has dimension \({{n}^{2}} + \left[ {\frac{n}{2}} \right] \) with n=dim V. The solutions are shown to give special values of the Jones polynomial of knot theory (in fact give a very elementary proof of its existence) and to give representations of the Temperley-Lieb algebra.
Thermostatic water bath for experimental studies in aqueous solutions

A temperature-controlled water bath for the study of ion-pairing equilibria and mineral solubility in aqueous solutions below 100/sup 0/C is described. The bath is similar to a previously described system (P.B. Hostetler and C.L. Christ, 1968, U.S. Geol. Survey Prof. Paper 600--D, p. D217--D221) but incorporates several significant improvements. Included among these are a more efficient stirring mechanism, a potentially larger solid-to-solution ratio, and improved equilibration of the gas phase with the solution.
Fundamentals of Energy Conversion

It is often taught in layman’s terms that “energy may be neither created nor destroyed” and this brings into question the meaning of “energy conservation.” Basic principles, such as energy conservation, stem from more general laws of Physics. The principles that govern the exchange and transformations of energy are succinctly examined in this chapter. The governing equations of energy conversion processes, or Laws of Thermodynamics, their corollaries and some of their applications to energy conversion processes are presented. A historical perspective is first given on the origins of modern energy conversion principles. The characteristics, significant variables/properties and types of Thermodynamic Systems are briefly explained. The two fundamental Laws of Thermodynamics (first and second) are postulated and the implications on the energy conversion processes are given succinctly. The operation of the simple gas and vapor power cycles is elucidated as well as several processes that are commonly used for the improvement of these cycles. Finally, the concept of exergy is introduced quantitatively and in detail. Based on exergy, several ways are presented on how this concept may be used to improve thermodynamic processes and cycles.
Promoting intergenerational learning in higher education: older adult perspectives on course auditing

ABSTRACTAs the population ages, colleges and universities have opportunities to promote intergenerational learning by inviting lifelong learners to engage with students in the classroom. This artic...
Distributed Processes and Scalability in Sub-networks of Large-Scale Networks.

Performance of standard processes over large distributed networks typically scales with the size of the network. For example, in planar topologies where nodes communicate with their natural neighbors, the scaling factor is $O(n)$, where $n$ is the number of nodes. As the size of the network increases, this makes global convergence over the entire network less practical. On the other hand, for several applications, such as load balancing or detection of local events, global convergence may not be necessary or even relevant. We introduce simple distributed iterative processes which limit the scope of the computational task to a smaller subnetwork of the entire network. This is achieved using one additional local parameter which controls the size of the subnetwork. We establish termination and convergence rate of such processes in theory, in experiment, in comparison to the well understood behavior of Markov processes, and for a variety of network topologies and initial conditions.
Almost Markov Processes

The methods described in this paper concern some work we have been doing recently on the simulation of large molecules: proteins, nucleic acids, etc. These simulations are becoming increasingly important in chemistry, biology, and medicine [1, 2]. Such calculations currently use an amount of supercomputer time comparable to that expended on lattice gauge theories, and it is growing constantly. Consequently, the efficiency of methods to simulate large molecules is of considerable importance.
Accrual Manipulations during IPO Lockup Expiration and the Monitoring Role of Auditors

This paper examines the presence of accrual manipulations during initial public offerings (IPOs) lockup period. We predict that insiders (mainly venture capitalists) inflate earnings around the lockup period to increase share price and maximize personal wealth from selling shares at lockup expiration. Consistent with our prediction, we find evidence that IPO firms engage in income-increasing current accruals manipulation in the lockup period. We also examine the impact of auditor quality in this unique setting. We find that IPO firms that hire prestigious auditors experience less earnings management in the lockup period than firms with lower-quality auditors, after controlling for the monitoring role of venture capitalist and underwriter reputation. In addition, IPO firms experience lower levels of earnings management during the fiscal year-end quarters when their financial statements are audited than in the interim quarters when their financials are reviewed.
Swimming, gliding, and rolling toward the mainstream: cell biology of marine protists

Marine protists are a polyphyletic group of organisms playing major roles in the ecology and biogeochemistry of the oceans, including performing much of Earth’s photosynthesis and driving the carbo...
Structural Property Guided Gait Parameter Estimation Using Footstep-Induced Floor Vibrations

This paper presents an approach that estimates occupants temporal gait parameters (e.g. step time, stride time, and initial loading response time) through structural floor vibrations while adapting to varying structural conditions. Continuous monitoring of these temporal gait parameters is a key component for elderly fall risk assessment and diagnosing injuries and gait abnormalities in home healthcare. A primary research challenge with using floor vibration sensing is that real-world deployments are often conducted in existing structures where little is known about the underlying structural properties. As such, prior works utilizing floor vibrations combine data-driven approaches with key heuristic observations to achieve accurate results, but often fail to adapt to varying structural conditions without re-training. To overcome this challenge, we present our approach, which extracts dynamic properties of the structure from footstep-induced vibrations and uses those properties to update gait parameter estimation models. By passively learning the dynamic properties of the structure, our approach enables gait parameter estimation that is robust to structural changes. We evaluate our approach by conducting real-world walking experiments on a test bed at Carnegie Mellon University.
3D Heterogeneous Integration with 2D Materials

As traditional device scaling slows down, three-dimensional (3D) integrated circuits (ICs) are needed to continue Moore’s Law advancements. We show that two-dimensional (2D) semiconductors are promising for heterogeneously integrated 3D ICs owing to their atomically thin nature and unique processing, thermal, and device capabilities.
Analytic Solutions for s-Process and i-Process Nucleosynthesis and Neutron Bursts

The s process, the i process, and neutron bursts are neutron-capture processes in which the temperature is typically too low to allow for photo-disintegration reactions. Nuclei are only produced by neutron-capture reactions and beta decays, and the network flow among the heavy nuclei is strictly one in which a nuclide transmutes into another nuclide with greater mass or charge. In such a case, the reaction network can be represented as a directed acyclic graph. We provide solutions to such networks in the case of constant temperature and neutron density. These solutions require sums over paths between pairs of species in the network, and we briefly discuss how such sums could be implemented. Our solutions will provide insights into nucleosynthesis relevant for isotopic abundances in meteoritic presolar grains and elemental abundances in extremely metal-poor stars.
Novel Use of Home Pulse Oximetry Monitoring in COVID-19 Patients Discharged From the Emergency Department Identifies Need for Hospitalization.

OBJECTIVES: Our objective was to evaluate patient-reported oxygen saturation (SpO2 ) using pulse oximetry as a home monitoring tool for patients with initially nonsevere COVID-19 to identify need for hospitalization. METHODS: Patients were enrolled at the emergency department (ED) and outpatient testing centers. Each patient was given a home pulse oximeter and instructed to record their SpO2 every 8 hours. Patients were instructed to return to the ED for sustained home SpO2 < 92% or if they felt they needed emergent medical attention. Relative risk was used to assess the relation between hospitalization and home SpO2 < 92% in COVID-19-positive patients. RESULTS: We enrolled 209 patients with suspected COVID-19, of whom 77 patients tested positive for COVID-19 and were included. Subsequent hospitalization occurred in 22 of 77 (29%) patients. Resting home SpO2 < 92% was associated with an increased likelihood of hospitalization compared to SpO2 ≥ 92% (relative risk = 7.0, 95% confidence interval = 3.4 to 14.5, p < 0.0001). Home SpO2 < 92% was also associated with increased risk of intensive care unit admission, acute respiratory distress syndrome, and septic shock. In our cohort, 50% of patients who ended up hospitalized only returned to the ED for incidental finding of low home SpO2 without worsening of symptoms. One-third (33%) of nonhospitalized patients stated that they would have returned to the ED if they did not have a pulse oximeter to reassure them at home. CONCLUSIONS: This study found that home pulse oximetry monitoring identifies need for hospitalization in initially nonsevere COVID-19 patients when a cutoff of SpO2 92% is used. Half of patients who ended up hospitalized had SpO2 < 92% without worsening symptoms. Home SpO2 monitoring also reduces unnecessary ED revisits.
Teaching While Black

A review of Matthew E. Henry's Teaching While Black. Main Street Rag Publishing Company, 2020. Matthew E. Henry's slim, searing first book of poems, Teaching While Black, is composed of situations or "teaching moments" that have occured throughout his life and particularly in his career as a Black teacher at mostly white and privileged schools. Particularly timely after the recent police killings of Breonna Taylor, George Floyd, and others, the poems, and the moments each represents, highlight the intersection of race, class, and gender politics, exploring the conflicted meanings of place, position, and identity for a Black educator. These are challenging, insightful, and passionate poems that would be ideal reading for courses focused on these issues, particularly in conjunction with the BLM protests that coincide with the collection's publication and with helping students both to understand and resist the received positions that society, or educational institutions assign them.
Pharmacologic heart failure treatment: A case-based review of current guidelines.

ABSTRACT Heart failure (HF) is a growing health problem associated with high morbidity and mortality. Use of evidence-based therapies improves clinical outcomes in patients with HF with reduced ejection fraction (HFrEF). However, in real-world research studies, adults with HFrEF were often medically undermanaged, including failure to use the right medications and failure to up titrate core HF therapies to doses similar to those used in randomized controlled trials. Although guidelines provide best-practice statements about care management, nurse practitioners and physician assistants (NPs and PAs) and clinical nurses often have questions about how to implement guideline-directed therapies in patient care management. With emerging new medications for managing HFrEF, and the possibility of new medications for patients with HF with preserved ejection fraction, complexity of care management will continue to increase. The aims of this review are to provide a summary of the 2017 updates to the national chronic HF management guidelines and use a case-based approach to discuss treatment change considerations associated with optimal guideline-based clinical care.
Delignification and Enzyme-Diffusion Kinetics of Radical Systems Treating Wheat Straw

Biomass pretreatment is often evaluated based on the degree of delignification and the yield of enzymatic hydrolysis. Thus, the phase delignification and enzyme diffusion kinetics models were utili...
Exploring the Heterogeneous Effects of Ecological and Structural Factors on Intensifying Neighborhood Economic Polarization

Scholars have recently reported the rise of neighborhoods at the extremes of the income distribution—both affluent and poor neighborhoods—and the loss of middle- or mixed-income neighborhoods. As t...
Inferring Cloud Interconnections: Validation, Geolocation, and Routing Behavior

Public clouds fundamentally changed the Internet landscape, centralizing traffic generation in a handful of networks. Internet performance, robustness, and public policy analyses struggle to properly reflect this centralization, largely because public collections of BGP and traceroute reveal a small portion of cloud connectivity.
Extinction of fear-potentiated startle: blockade by infusion of an NMDA antagonist into the amygdala.

Data derived from in vitro preparations indicate that NMDA receptors play a critical role in synaptic plasticity in the CNS. More recently, in vivo pharmacological manipulations have suggested that an NMDA- dependent process may be involved in specific forms of behavioral plasticity. All of the work thus far has focused on the possible role of NMDA receptors in the acquisition of responses. However, there are many examples in the behavioral literature of learning-induced changes that involve the reduction or elimination of a previously acquired response. Experimental extinction is a primary example of the elimination of a learned response. Experimental extinction is well described in the behavioral literature, but has not received the same attention in the neurobiological literature. As a result, the neural mechanisms that underlie this important form of learning are not at all understood. In the present experiments, the fear-potentiated startle paradigm was employed to begin to investigate neural mechanisms of extinction. The results show that infusion of the NMDA antagonist D,L-2- amino-5-phosphonovaleric acid (AP5) into the amygdala, a limbic structure known to be important for fear conditioning, dose-dependently blocked extinction of conditioned fear. Control experiments showed that the blockade of extinction was neither the result of the permanent disruption of amygdaloid function nor the result of decreased sensitivity of the animals to the conditioned stimulus. Infusion of AP5 into the interpositus nucleus of the cerebellum, a control site, did not block extinction. Finally, intra-amygdala infusion of a selected dose of the non-NMDA antagonist 6-cyano-7-nitroquinoxaline-2,3-dione did not block extinction of conditioned fear. These results, together with a previous report from our laboratory (Miserendino et al., 1990), demonstrate the importance of the amygdala in the elaboration of conditioned fear and suggest that an NMDA-dependent process might underlie the extinction of conditioned fear.
So That Others Might Also Live

Night Falls Fast Understanding Suicide. Kay Redfield Jamison. Knopf, New York, 1999. 446 pp. $26. ISBN 0-375-40145-8. In this account of the biological and psychological reasons that interact to cause suicide and the strategies being developed to combat them, Jamison blends straightforward reports of facts and figures with lyrical essays about individual deaths.
Camera calibration methodology based on a linear perspective transformation error model

The camera model which uses homogeneous coordinates, assumes the laws of Gaussian optics, and an extension for the aberration of geometric radial distortion is included. Features that collectively demonstrate the methodology's superiority over existing techniques are: (1) the simultaneous and accurate inference of all camera model parameters using only iterative linear least squares; (2) no requirement of a priori knowledge of camera model parameters; (3) utilization with a wide range of optical sensing devices; (4) adaptability to include camera model parameters that are departures from the assumptions of Gaussian optics; and (5) computational efficiency. Absolute stereo calibration accuracy of 0.084 mm in a 2000 cm/sup 3/ volume is achieved for a pair of miniaturized CCD array cameras. >
The Dual Gravimetric Hot‐Air Method for Measuring Soil Water Diffusivity

The hot-air method provides rapid measurement of a soil9s unsaturated hydraulic diffusivity function. The original method consists of blowing hot air across one end of a soil column for a short period, and then quickly extruding, dissecting, and oven drying the soil to provide the soil water content profile, which is used to calculate the soil9s unsaturated hydraulic diffusivity. This research presents a novel approach to measuring the soil water content profile during a hot-air test. During the drying process, a soil column is suspended in a horizontal position by a load cell attached at each end. The measured change in force from the two load cells enables calculation of the soil water content profile, without soil extrusion, dissection, and oven drying. Because the test is nondestructive, it permits estimation of the water content profile and calculation of the unsaturated hydraulic diffusivity function at multiple times. Similarity of the diffusivity functions at various times during the drying process provides evidence of proper testing conditions, a utility not available with the destructive approach. We applied the method to a silt loam and a clay loam and both soils achieved a RMSE of 0.012 compared with the traditionally measured water content profile. We also modeled the performance of the new method on previously published hot-air water content profiles and achieved similar results.
Service markets and competition

Abstract The production and delivery of services differ from manufacturing in ways which have a significant impact on the nature of market competition. Contracts for manufactured goods are centered around a clearly defined junction between production and use, made possible by the properties of tangibility and portability of tangible goods, at which point responsibility for use, operation and consumption of the product is transferred from producer to customer, along with ownership. Service operations, by contrast, involve a lack of inventories and portability, customer contact, joint production, customer-specific inputs, and intangibility in varying degrees. Moreover, service operations are either entirely post contractual or interlinked with the contracting process. As a result, the very nature of service markets and contracting depends on the characteristics of the service operation. While the operational consequences of service characteristics have been explored quite widely, there is less understanding of the special features of service competition and its implications for service strategy. We provide a framework for describing, analyzing and explaining service competition and review some old and new models which address the special features of service markets.
Lake Erie Microcystis: Relationship between microcystin production, dynamics of genotypes and environmental parameters in a large lake

Cyanobacteria of genus Microcystis sp. have been commonly found in Lake Erie waters during recent summer seasons. In an effort to elucidate relationships between microcystin production, genotypic composition of Microcystis community and environmental parameters in a large lake ecosystem, we collected DNA samples and environmental data during a three-year (2003–2005) survey within Lake Erie and used the data to perform a series of correlation analyses. Cyanobacteria and Microcystis genotypes were quantified using quantitative real-time PCR (qPCR). Our data show that Microcystis in Lake Erie forms up to 42% of all cyanobacteria, and that Microcystis exists as a mixed population of potentially toxic and (primarily) non-toxic genotypes. In the entire lake, the total abundance of Microcystis as well as the abundance of microcystin-producing Microcystis is strongly correlated with the abundance of cyanobacteria suggesting that Microcystis is a significant component of the cyanobacterial community in Lake Erie during summer seasons. The proportion of total Microcystis of all cyanobacteria was strongly linked to the microcystin concentrations, while the percentage of microcystin-producing genotypes within Microcystis population showed no correlation with microcystin concentrations. Correlation analysis indicated that increasing total phosphorus concentrations correlate strongly with increasing microcystin concentrations as well as with the total abundance of Microcystis and microcystin-producing Microcystis.
CELLULAR AND IMMUNOGLOBULIN CONTENT OF NEONATAL MILK

The cellular and immunoglobulin content of neonatal breast secretions from 12 full term infants less than 10 days post delivery was studied. Precision pipettes were used to aspirate the mammary gland secretion directly from the neonates cleaned nipple/areola skin surface. Cleaning was performed with sterile cotton and water and air dried. For measurement of the immunoglobulin concentration, direct innoculation of the neonatal milk into radial immunodiffusion plates, using the kailestad low level IgA, IgM, and IgG kit was performed. Cell viability was assessed using the trypan blue exclusion technique and the differential cell count was performed on a cytocentrifuged preparation following Wrights staining. Although cell viability was greater than 90 percent, fewer cells per ml of fluid were found in neonatal milk than are reported in mother's milk. The predominant cell types observed were lymphocytes and macrophages. The immunoglobulin content was predominantly IgG with minimal concentration of IgA, and no IgM detected. These data suggest similar but different cellular and immunoglobulin regulatory mechanisms in neonatal breast secretions as compared to mothers' milk and indicate a need for further study to determine the clinical significance of these observations.
Purification of a toxin from tentacles of the anemone Condylactis gigantea

A toxin from the tentacles of the anemone Condylactis gigantea has been partially purified. This toxin, which paralyzes crustacea, is a water-soluble protein. Recovery from an acetone powder is nearly total. High yields with large increases in specific activity are obtained using gel filtration and anion exchange resins. Partial purification reveals the existence of only one toxic component, with a mol. wt. of 10,000–15,000 and which appears to be basic. It is extremely potent with an ld50 (crayfish) of under 1 μg per kg.
Stimulation of the Subthalamic Nucleus in a Patient With Parkinson Disease and Essential Tremor

Background The preferred surgical target for the treatment of Parkinson disease (PD) is either the internal globus pallidus or the subthalamic nucleus (STN); the target for treatment of essential tremor (ET) is the thalamic subnucleus ventralis intermedius (Vim). Some patients with PD have coexistent ET, and the identification of a single surgical target to treat both parkinsonian motor symptoms and ET would be of practical importance. Objective To describe the use of the STN target in deep brain stimulator (DBS) surgery to treat PD motor symptoms and the action-postural tremor of ET. Design Case report. Patient A 62-year-old man had a greater than 30-year history of action-postural tremor in both hands, well controlled with β-blockers for more than 20 years. He developed resting tremor, bradykinesia, and rigidity on his right side that progressed to his left side during the past 10 years. Dopaminergic medication improved his rigid-ity and bradykinesia, with only mild improvement of his resting tremor and no effect on his action-postural tremor. Interventions Left pallidotomy followed by placement of a left DBS in the Vim and subsequent placement of a right STN DBS. Main Outcome Measures Control of symptoms of PD and ET. Results The left pallidotomy controlled the patient’s parkinsonian motor symptoms on the right side of his body, but did not affect the action-postural component of his tremor. The symptoms on the left side of the body, including both an action-postural and a resting tremor (as well as the rigidity and bradykinesia), improved after placement of a single right STN DBS. Conclusion Placement of an STN DBS should be considered as the procedure of choice for surgical treatment of patients with a combination of PD and ET.
On the hypothesized relation between giftedness and creativity

Our knowledge of giftedness as it develops into creativity is primitive. New theory and new research methods are needed. Indeed, a distinct psychology of exceptional achievement is necessary.
Decision support for the career field selection process at the US Air Force Academy

Abstract Each year, the US Air Force Academy graduates nearly 1000 young men and women. To support the decision of which cadets will be classified into which career fields, we describe a linear programming formulation with appealing computational properties that enable it as the core of a decision support tool. We explore methods for measuring and balancing cadets' class standing, Air Force career field requirements, and cadets' career field preferences in the context of this model. Our computational experiments demonstrate the improvement of this method over previous classification approaches, yielding more than 10% increase in the number of cadets assigned to their top career field choice and yielding nearly a 100% reduction in the number of cadets not receiving any of their career field choices. We also explore alternative methods for measuring cadets' career field preferences and demonstrate the positive effect of the new measurement scheme on the overall classification. Because of the short running time of this model, it will serve as a flexible, real-time component of the Academy's classification process.
CytoJournal's move to the new platform: More on financial model to the support open-access charter in cytopathology, publication quality indicators, and other issues

As discussed during the Nov, 2008 editorial board meeting (corresponding with the 56th Annual American Society of Cytopathology (ASC) Scientific Meeting at Orlando, FL, USA), CytoJournal has moved to a new platform (MedKnow Publications, http://www.medknow.com/). Currently most of the aspects of the move are complete. PDFs of all the articles published previously in CytoJournal before June 2008[1–86] will continue to be available on the new platform under the same URL of www.cytojournal.com (in the top blue bar, click on ‘Browse articles’ http://www.cytojournal.com/browse.asp) or click on ‘Search CytoJ Articles’ http://www.cytojournal.com/search.asp). They will also be available through other sites including PubMed (http://www.ncbi.nlm.nih.gov/PubMed/). All the articles published after the June, 2008 move would be available free under open access charter in HTML format. The PDFs will be available free to all Cytopathology Foundation members (http://www.cytojournal.com/CFMember.asp) and to the members of various organizations joining the ‘CytoJ OA steward’ program (http://www.cytojournal.com/OASteward.asp).
Electrochemical oxidation of (Ph4As)[IrCl2(CO)2] in the presence of tetra(alkyl)ammonium salts. Electrocrystallization of different forms of iridium-based linear chain complexes

The conducting iridium complexes (TAA) x [IrCl 2 (CO) 2 ] (where TAA is tetra(n-hexyl)-ammonium, tetra(n-butyl)ammonium, and tetra(ethyl)ammonium cation, and x = 0.55, 0.62, and 0.55, respectively) were electrochemically synthesized on a gold electrode through electro-oxidation of [IrCl 2 (CO) 2 ] - in various organic solvents (dichloromethane, 1,2-dichloroethane, acetonitrile, and 4:1 toluene/acetonitrile) using cyclic voltammetry. In dichloromethane and 1,2-dichloroethane electrocrystallization results in formation of long, randomly distributed crystalline needles on the electrode surface. The solid phase grows by a progressive nucleation mechanism followed by one-dimensional growth of microcrystals. These crystals are reversibly reduced in a subsequent anodic voltammetric potential scan. They can also be oxidized at more positive potentials. This second oxidation process results in structural changes of the solid phase and its slow dissolution. In a solution containing tetra(n-butyl)ammonium cations, the deposit forms two distinct structures that can be observed visually. The initially produced film forms an irregular porous structure on the electrode surface. Subsequently, needlelike crystals are deposited on the electrode surface. In a toluene/acetone mixture the process of [IrCl 2 (CO) 2 ] - oxidation under multicyclic voltammetry conditions results in the formation of a stable electroactive species on the electrode surface. In polar solvents, such as N,N-dimethylformamide or dimethyl sulfoxide, the irreversible oxidation of [IrCl 2 (CO) 2 ] - occurs without precipitation of any deposit at the electrode surface.
Theory of the doped quantum well superlattice APD: A new solid-state photomultiplier

A new superlattice avalanche photodiode structure consisting of repeated unit cells formed from a p-i-n Al 0.45 Ga 0.55 As region immediately followed by near intrinsic GaAs and Al 0.45 Ga 0.55 As layers is examined using an ensemble Monte Carlo calculation. The effects of various device parameters, such as the high-field layer width, GaAs well width, low-field AlGaAs layer width, and applied electric field on the electron and hole ionization coefficients is analyzed. In addition, the fraction of electrons which ionize in a spatially deterministic way, at the same place in each stage of the device, is determined. As is well known, completely noiseless amplification can be achieved if each electron ionizes in each stage of the device at precisely the same location while no holes ionize anywhere within the device. A comparison is made between the doped quantum well device and other existing superlattice APD's such as the quantum well and staircase APD's. It is seen that the doped quantum well device most nearly approximates photomultiplier-like behavior when applied to the GaAs/AlGaAs material system amongst the three devices. In addition, it is determined that none of the devices, when made from GaAs and AlGaAs, fully mimic ideal photomultiplier-like performance. As the fraction of electron ionizations per stage of the device is increased, through variations in the device geometry and applied electric field, the hole ionization rate invariably increases. It is expected that ideal performance can be more closely achieved in a material system in which the conduction band edge discontinuity is a greater fraction of the band gap energy in the narrow-band gap semiconductor.
Explaining Team-Based Pay: A Contingency Perspective Based on the Organizational Life Cycle, Team Design, and Organizational Learning Literatures

Abstract Using a contingency perspective that combines the organizational life cycle, team design, and organizational learning literatures, a total of 12 propositions are developed to explain and predict the application of team-based pay in organizations. In essence, this article argues that financial capabilities (associated with various stages in the life cycle) and human capital capabilities (represented by factors leading to an organization's absorptive capacity) should have a major impact on the application of team-based pay. It is also expected that situational favorableness for team pay (as determined by team task design) should influence the likelihood of its application in an organization.
Mixed-mode toughness of human cortical bone containing a longitudinal crack in far-field compression

Bone is generally loaded under multiaxial conditions in vivo; as it invariably contains microcracks, this leads to complex mixed-mode stress-states involving combinations of tension, compression and shear. In previous work on the mixed-mode loading of human cortical bone (using an asymmetric bend test geometry), we found that the bone toughness was lower when loaded in far-field shear than in tension (opposite to the trend in most brittle materials), although only for the transverse orientation. This is a consequence of the competition between preferred mechanical vs. microstructural crack-path directions, the former dictated by the direction of the maximum mechanical “driving force” (which changes with the mode-mixity), and the latter by the “weakest” microstructural path (which in human bone is along the osteonal interfaces or cement lines). As most microcracks are oriented longitudinally, we investigate here the corresponding mixed-mode toughness of human cortical bone in the longitudinal (proximal–distal) orientation using a “double cleavage drilled compression” test geometry, which provides a physiologically-relevant loading condition for bone in that it characterizes the toughness of a longitudinal crack loaded in far-field compression. In contrast to the transverse toughness, results show that the longitudinal toughness, measured using the strain-energy release rate, is significantly higher in shear (mode II) than in tension (mode I). This is consistent, however, with the individual criteria of preferred mechanical vs. microstructural crack paths being commensurate in this orientation.
Demonstration of amylolytic activity in cultures of Endamoeba histolytica

An amylolytic substance is elaborated by growing cultures of the Denton and Faust 22 strains of Endamoeba histolytica. This substance is diffusible into the solid phase of the culture medium used.
Replicative stress induces intragenic transcription of the ASE1 gene that negatively regulates Ase1 activity.

Summary Intragenic transcripts initiate within the coding region of a gene, thereby producing shorter mRNAs and proteins. Although intragenic transcripts are widely expressed [1], their role in the functional regulation of genes remains largely unknown. In budding yeast, DNA replication stress activates the S phase checkpoint that stabilizes replication forks and arrests cells in S phase with a short spindle [2–4]. When yeast cells were treated with hydroxyurea (HU) to block DNA synthesis and induce replication stress, we found that Ase1, a conserved spindle midzone protein [5], appeared as two short protein isoforms in addition to the full-length protein. We further demonstrated that the short isoforms result from intragenic transcription of ASE1 , which depends on the S phase checkpoint. Blocking generation of the short isoforms leads to a destabilized S phase spindle, characterized by increased spindle dynamics and frequent spindle collapse. Because the short Ase1 isoforms localize at the spindle in HU-treated cells and overexpression of the short Ase1 isoforms impairs the spindle midzone localization of full-length Ase1, it is likely that the presence of short Ase1 isoforms stabilizes the spindle by antagonizing full-length Ase1. Together, our results reveal intragenic transcription as a unique mechanism to downregulate gene functions in response to DNA replication stress.
Prevention of ischemic injury in renal transplantation.

Case presentation The prospective donor was a 17-year-old white female who had sustained a severe head injury in a motor vehicle accident. By the time she was brought to the Emergency Room, she had evidence of cerebral edema and increased intracerebral pressure; she was given intravenous dexamethasone, 10 mg, and mannitol, 100 ml of a 25% solution. Intravenous naloxone, 2 mg, was given empirically but had no effect on her neurologic condition. Surgical exploration of her wounds required the use of pancuronium, fentanyl, and thiamylal as anesthetic agents. In addition, she was given 100 mg of phenytoin intramuscularly to prevent seizures; 1 g of cefazolin intravenously as infection prophylaxis; and 300 mg of cimetidine intravenously to prevent gastric ulcers. Neurologic examination following her recovery from anesthesia could not demonstrate a response to painful external stimuli; corneal, vestibulocular, and gag reflexes were absent; the pupils were fixed; and neither motor nor cranial nerve responses could be elicited. Electroencephalography revealed no electrocerebral activity. An apnea test disclosed no spontaneous muscular movement or respiration despite a rise in the PaCO2 to 60mm Hg. At the conclusion of the test, ventricular tachycardia was successfully treated with 100 mg of lidocaine intravenously. Over a 4-hour period, the patient's urine flow averaged 512 mI/hr and she received an average of 410 mI/hr of 0.9% sodium chloride solution intravenously. At that time, the blood pressure was 106/62 mm Hg; pulse, 104 beats/mm; and temperature, 370 C. Laboratory data were: serum sodium, 155 mEq/liter; potassium, 3.4 mEq/liter; chloride, 124 mEq/liter; bicarbonate, 19 mEq/liter; and glucose, 720 mg/dl. The BUN was 13 mg/cl! and the serum creatinine 1.2 mg/dl. The hematocrit was 35.7%; white blood cell count, 27,100 mm3; and platelets, 272,000 mm3. Urinalysis showed a specific gravity of 1.010, a pH of 5.0, and 2+
Rapid, high-resolution 14C chronology of ooids

Abstract Ooids are small, spherical to ellipsoidal grains composed of concentric layers of CaCO 3 that could potentially serve as biogeochemical records of the environments in which they grew. Such records, however, must be placed in the proper temporal context. Therefore, we developed a novel acidification system and employed an accelerator mass spectrometer (AMS) with a gas accepting ion source to obtain radiocarbon ( 14 C) chronologies extending radially through ooids within one 8-h workday. The method was applied to ooids from Highborne Cay, Bahamas and Shark Bay, Australia, yielding reproducible 14 C chronologies, as well as constraints on the rates and durations of ooid growth and independent estimates of local 14 C reservoir ages.
Viewpoint What should we teach new software developers? Why?

Fundamental changes to computer science education are required to better address the needs of industry.
Parasites and Diarrhea. I: Protozoans and Diarrhea

Intestinal parasitism is extremely common, with approximately 70% of all people harboring one or more intestinal parasite. Parasitism and diarrhea are both hyperendemic in areas where sanitation is suboptimal. Many clinicians assume that the identification of intestinal parasites in patients with diarrhea implies that the parasites are the cause. This approach is frequently misguided. Some intestinal parasites such as Giardia lamblia and Entamoeba histolytica certainly do cause diarrhea. Others, for example Entamoeba coli and Ascaris lumbricoides, almost certainly do not. In addition, there are a number of other organisms that have been associated with diarrheal illness in some cases, which may or may not be important pathogens. In this article, we will review the role of protozoans as definite and possible causes of diarrhea. In Part II, we review the role of helminths in diarrhea.
Some aspects of the efficiency of statistical methods of particle size analysis

Abstract In statistical methods of particle size analysis by microscopy the analyst seeks to isolate a parameter of the particle profile which can be measured with a minimum of decision-taking and then relates mathematically this prime parameter to other parameters which have physical significance for the system being analyzed. The reason why these methods are called statistical techniques is that usually they, rely on some statistical averaging of the prime parameter in order to obtain some quantity which can be related to the physical parameter of interest. In this study the efficiency of current statistical methods is explored. It is shown that considerable semantic confusion concerning “random chord” populations exists in the literature and standard definitions are proposed. The use of Martin's and Feret's diameter in size analysis is explored. Techniques for improving the efficiency of statistical methods using antithetic variable principles and averaging techniques in which errors cancel instead of accumulating are suggested.
Mortality Benefit of Implantable Cardioverter-Defibrillator Therapy in Patients With Persistent Malignant Ventricular Arrhythmias Despite Amiodarone Treatment

Implantable cardioverter defibrillators (ICDs) are very effective in preventing sudden cardiac death. However, debate continues as to whether ICD implantation is superior to amiodarone in prolonging survival in patients with life-threatening ventricular arrhythmias. Of 442 consecutive patients treated with amiodarone, we identified 48 patients with symptomatic ventricular arrhythmias who met all of the following inclusion criteria: (1) had inducible sustained ventricular tachycardia at baseline electrophysiologic study, (2) had an oral amiodarone load of at least 10 g over 10 to 14 days, (3) remained inducible with a hemodynamically unstable ventricular arrhythmia at follow-up electrophysiologic study, and (4) were advised to continue amiodarone therapy and undergo ICD implantation. Patients who agreed to undergo ICD implantation (n = 28) had a lower ejection fraction (29 +/- 9% vs 40 +/- 12% p <0.005) and were younger (61.0 +/- 10 vs 69 +/- 7 years, p <0.01) than patients who refused device implantation (n = 20). Using a Cox proportional-hazards model, defibrillator therapy was the strongest independent predictor of improved survival in patients with an ejection fraction < or =40% (RR = 0.42; 95% confidence interval 0.22 to 0.79). Thus, patients with depressed ejection fraction and continued inducibility of sustained ventricular tachycardia despite oral amiodarone loading have a poor prognosis. In such patients, ICDs are associated with a 58% reduction in total cardiac mortality.
Echinomycin binding sites on DNA

The preferred binding sites of echinomycin on DNA can be determined by a method called "footprinting." A 32P end-labeled restriction fragment from pBR322 DNA is protected by binding to echinomycin, and cleaved by a synthetic DNA cleaving reagent, methidiumpropyl--EDTA . Fe(II); the DNA cleavage products are then subjected to high-resolution gel analyses. This method reveals that echinomycin has a binding site size of four base pairs. The strong binding sites for echinomycin contain the central two-base-pair sequence 5'-CG-3'. From an analysis of 15 echinomycin sites on 210 base pairs of DNA, key recognition elements for echinomycin are contained in the sequences (5'-3') ACGT and TCGT (A, adenine; C, cytosine; G, guanine; T, thymine).
Accumulation of individual histone mRNAs during embryogenesis of the sea urchin Strongylocentrotus purpuratus.

We have determined that the stockpile of maternal histone mRNAs for both H2B and H3 in eggs of the sea urchin Strongylocentrotus purpuratus corresponds to 0.8–1 million molecules per egg. This value is a somewhat smaller quantity than had previously been estimated. On the other hand, the increase brought about by embryonic mRNA synthesis is 10- to 12-fold, rather than 4-fold. Further analysis of the time course of accumulation of these mRNAs suggests that histone gene expression in early development involves a complex interaction between activation of stockpiled maternal messengers, fluctuating rates of histone gene transcription, and alterations of histone mRNA stability. The maternal pool of H1 mRNA is considerably smaller (80,000 molecules). During cleavage, it partially catches up and peaks at about half the value for H2B and H3. We also examined previtellogenic oocytes for the presence of histone mRNAs by the same methods and were unable to detect any. Thus the stockpile of maternal histone mRNAs must accumulate after the previtellogenic stage of oogenesis.
Joint Congestion Control and Wireless-Link Scheduling for Mobile TCP Applications

We consider joint congestion control and wireless link-scheduling design for mobile TCP applications. Adopting queueing delay as the congestion measure, we show that the optimal TCP congestion control and link scheduling scheme amounts to window-control oriented implicit primal-dual solvers for underlying network utility maximization. Based on this idea, we develop readily deployable, scalable yet optimal TCP congestion control schemes for the Internet with coupled wireless links, provided that the wireless access point performs a queueing-delay based link scheduling. Global convergence/stability of the proposed schemes to optimal network equilibrium is proved using a Lyapunov method. Simulation results are provided to evaluate the proposed schemes in practical network environments.
Single Molecule Analysis of the Arabidopsis FRA1 Kinesin Shows that It Is a Functional Motor Protein with Unusually High Processivity

ABSTRACT The Arabidopsis FRA1 kinesin contributes to the organization of cellulose microfibrils through an unknown mechanism. The cortical localization of this kinesin during interphase raises the possibility that it transports cell wall-related cargoes along cortical microtubules that either directly or indirectly influence cellulose microfibril patterning. To determine whether FRA1 is an authentic motor protein, we combined bulk biochemical assays and single molecule fluorescence imaging to analyze the motor properties of recombinant, GFP-tagged FRA1 containing the motor and coiled-coil domains (designated as FRA1(707)–GFP). We found that FRA1(707)–GFP binds to microtubules in an ATP-dependent manner and that its ATPase activity is dramatically stimulated by the presence of microtubules. Using single molecule studies, we found that FRA1(707)–GFP moves processively along microtubule tracks at a velocity of about 0.4 μm s −1 . In addition, we found that FRA1(707)–GFP is a microtubule plus-end-directed motor and that it moves along microtubules as a dimer. Interestingly, our single molecule analysis shows that the processivity of FRA1(707)–GFP is at least twice the processivity of conventional kinesin, making FRA1 the most processive kinesin to date. Together, our data show that FRA1 is a bona fide motor protein that has the potential to drive long-distance transport of cargo along cortical microtubules.