cssi/SciSciGPT-SciSciNet huggingface dataset:
Evolution Of Crystalline Microstructure in GeTe Thin Films for Optical Storage Applications

The bit-erase process in phase-change optical storage is based on the amorphous to crystalline transformation. While there has been significant progress developing compositions and multilayered media for phase-change applications, quantitative studies of the crystallization kinetics and microstructural development are generally lacking. This paper describes work quantifying crystallization in GeTe thin films. Microstructural changes during isothermal annealing are measured using in-situ hot-stage optical microscopy. This technique measures the fraction crystallized, the number of crystallites, and crystallite radii as a function of time. These data are sufficient to deconvolute the individual contributions of nucleation and growth. We find an Avrami exponent of ≈4, consistent with time-resolved reflection/transmission studies. This exponent is due to 2-D growth at a constant rate plus transient nucleation. The data are used in a kinetic model to simulate non-isothermal crystallization during focused-laser heating characteristic of the bit-erase process.
New connection between central engine weak physics and the dynamics of gamma-ray burst fireballs

We demonstrate a qualitatively new aspect of the dynamics of gamma-ray burst (GRB) fireballs: the development of a substantial dispersion in the proton component in fireballs in which neutron decoupling occurs and is sufficiently pronounced. This effect depends sensitively on the neutron to proton ratio in the fireball, becoming more dramatic with increasing neutron excess. Simple physical arguments and transport calculations indicate that the dispersion in the Lorentz factor of the protons can be of the order of the final mean Lorentz factor of the fireball. We show how plasma instabilities could play an important role in the evolution of the fireball and how they might ultimately govern the development of such a velocity dispersion in the proton component. The role of these instabilities in setting or diminishing a proton Lorentz factor dispersion represents a new and potentially important venue for the study of plasma instabilities. Significant dispersion in the proton velocities translates into fewer protons attaining the highest Lorentz factors. This is tantamount to a reduction in the total energy required to attain a given Lorentz factor for the highest energy protons. As well, a velocity dispersion in the proton component can have consequences for the electromagnetic and neutrino signature of GRB's.
Tribological behavior of WC/DLC/WS2 nanocomposite coatings

Abstract The sliding behavior of amorphous DLC coatings, with or without hydrogen (i.e., a-C or a-C:H), depends on environment. Nanocomposite coatings developed at the Air Force Research Laboratory are designed for operation in environments ranging from humid air to the vacuum of space, as required for aerospace applications. A magnetron sputter-assisted pulsed laser deposition process was used to produce coatings with a matrix of DLC and nanoparticles of both WC and WS2. Coatings were tested on a pin/disk tribometer equipped with an environmental chamber and an in situ Kelvin probe. Low friction was achieved in both air and vacuum. Post-test characterization of disk wear tracks, pin wear scars and debris involved the use of scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), focused ion beam/transmission electron microscopy (FIB/TEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Surface material with mixed components dominates the tribological behavior of these coatings in both air and vacuum. Molecular dynamics (MD) is being used to model an amorphous material containing crystalline nanoparticles. Results suggest that soft particles (e.g., WS2) tend to mix with the local matrix material rather than spreading on the surface as a separate layer. This is consistent with experimental observations.
Bootstrapping Privacy Compliance in Big Data Systems

With the rapid increase in cloud services collecting and using user data to offer personalized experiences, ensuring that these services comply with their privacy policies has become a business imperative for building user trust. However, most compliance efforts in industry today rely on manual review processes and audits designed to safeguard user data, and therefore are resource intensive and lack coverage. In this paper, we present our experience building and operating a system to automate privacy policy compliance checking in Bing. Central to the design of the system are (a) Legal ease-a language that allows specification of privacy policies that impose restrictions on how user data is handled, and (b) Grok-a data inventory for Map-Reduce-like big data systems that tracks how user data flows among programs. Grok maps code-level schema elements to data types in Legal ease, in essence, annotating existing programs with information flow types with minimal human input. Compliance checking is thus reduced to information flow analysis of big data systems. The system, bootstrapped by a small team, checks compliance daily of millions of lines of ever-changing source code written by several thousand developers.
The Acquisition and Use of Social Knowledge Basic Postulates and Representative Research

The assumptions underlying current research and theory on the acquisition of social knowledge are presented in terms of a set of postulates pertaining to the interpretation, organization, storage, and retrieval of information for use in making judgments. Representative research applying these principles and bearing on their validity is discussed, with particular emphasis given to (a) recency effects in recall and judgments, (b) the role of different goals on the processing of social information, and (c) the role of prototypic schemata in organizing information.
TNFα potentiates glutamate neurotoxicity by inhibiting glutamate uptake in organotypic brain slice cultures: neuroprotection by NFκB inhibition

Glutamate and the proinflammatory cytokine, tumor necrosis factor alpha (TNF alpha), have been suggested to contribute to neurodegenerative diseases. We investigated the interaction of TNF alpha and glutamate on neuronal cell death using fluorescence propidium iodide uptake in rat organotypic hippocampal-entorhinal cortex (HEC) brain slice culture that maintains the cytoarchitecture of the intact brain. Time course and concentration studies indicate that glutamate produced significant neuronal cell death in all four brain areas examined, for example, entorhinal cortex, hippocampal CA1 and CA3 fields, and dentate gyrus. TNF alpha alone at concentration of 20 ng/ml caused little or no detectable neuronal cell death, however, when combined with submaximal glutamate (3.3 mM), TNF alpha significantly increased and accelerated glutamate neurotoxicity. TNF alpha potentiation of glutamate neurotoxicity is blocked by NMDA receptor antagonists but not by AMPA antagonists CNQX and NBQX. Studies directly measuring [14C]-glutamate uptake in HEC slices indicate that TNF alpha dose-dependently inhibited glutamate uptake. Further, inhibitors of glial glutamate transporters potentiated glutamate neurotoxicity similar to TNF alpha. The antioxidant butylated hydroxytoluene (BHT) and the NF kappa B inhibitor PTD-p65 peptide inhibit NF kappa B activation and TNF alpha potentiation of glutamate neurotoxicity. BHT prevented the inhibition of TNFalpha on glutamate transport in HEC slices and also blocked nuclear translocation of NF kappa B subunit p65. These data indicate that TNF alpha and glutamate can act synergistically to induce neuronal cell death. TNF alpha potentiation of glutamate neurotoxicity through the blockade of glutamate transporter activity may represent an important mechanism of neurodegeneration associated with neuroinflammation.
Posttransplantation de novo tumors in liver allograft recipients

De novo cancers occurred after transplantation in 8,008 organ allograft recipients, who developed 8,531 different types of malignancy. Three hundred twenty-four liver recipients developed 329 cancers. There were striking differences in the patterns of neoplasms observed when these were compared with 7,200 tumors that occurred in renal allograft recipients. Lymphomas were much more common in liver allograft recipients (57% v 12% of all tumors), whereas skin cancers (39% v 15%), carcinomas of the cervix (4% v 1%), renal tumors (4% v 1%), and vulvar carcinomas (3% v 0.6%) were more common in renal allograft recipients. The high incidence of lymphomas is related partly to the more intense immunosuppressive therapy administered to hepatic allograft recipients and partly to the large percentage of pediatric patients among them. The intense immunosuppression also accounts for the much shorter induction times of lymphomas (mean, 15 v 46 months; P < .001) and nonlymphomatous tumors (mean, 27 v 72; P < .001) in liver compared with kidney recipients. The longer follow-up of renal recipients probably accounts for the higher incidence of the other tumors that tend to appear relatively late after transplantation. A remarkable feature was the high incidence of allograft involvement by lymphoma (44%). Complete remissions after treatment occurred in 11 of 28 patients in whom the lymphoma was confined to the allograft. A few tumors in liver recipients were related to the underlying disease for which transplantation was performed: hepatomas in patients who underwent transplantation for hepatitis B cirrhosis and colon carcinomas or cholangiocarcinomas in patients who underwent transplantation for chronic ulcerative colitis with sclerosing cholangitis. A surprising finding was the development of four leiomyosarcomas, three occurring in the allograft itself, in pediatric liver recipients. Copyright © 1996 by the American Association for the Study of Liver Diseases.
Shock-induced transformations in the system NaAlSiO4−SiO2 : a new interpretation

New internally consistent interpretations of the phases represented by the high pressure phase shock wave data for an albite-rich rock, Jadeite, and nepheline in the system NaAlSiO_4-SiO_2, are obtained using the results of static high pressure investigations, and the recent discovery of the hollandite phase in a shocked meteorite. We conclude that nepheline transforms directly to the calcium ferrite structure, whereas albite transforms possibly to the hollandite structure. Shock Hugoniots for the other plagioclase and alkali feldspars also indicate that these transform to hollandite structures. The pressure-volume data at high pressure could alternatively represent the compression of an amorphous phase. Moreover, the shock Hugoniot data are expected to reflect the properties of the melt above shock stresses of 60–80 GPa. The third order Birch-Murnaghan equation of state parameters are: K_(os) = 275±38 GPa and K′_(os) = 1.6±1.5 for the calcium ferrite type NaAlSiO_4, K_(os) = 186±33 GPA and K′_(os) = 2.6±1.7 for the albite-rich hollandite, K_(os) = 236±45 GPa and K′_(os) = 2.3±2.0 for the orthoclase-rich hollandite, and K_(os) = 190 to 210 GPa and K′_(os) ≈ 2.2 for the anorthite-rich hollandite.
Tranexamic acid reduces bleeding after cardiopulmonary bypass when compared to epsilon aminocaproic acid and placebo.

UNLABELLED Perioperative bleeding following coronary artery bypass grafting (CABG) is associated with increased blood product usage. Although aprotonin is effective in reducing perioperative blood loss, excessive cost prohibits routine utilization. Epsilon aminocaproic acid (EACA) and tranexamic acid (TA) are inexpensive antifibrinolytic agents, which, when given prophylactically, may reduce blood loss. The present study was undertaken to compare the efficacy of TA and EACA in reducing perioperative blood loss. METHODS The study population consisted of first-time CABG patients. Patients were allocated in a prospective double-blind fashion: (1) group EACA (loading dose 15 mg/kg, continuous infusion 10 mg/kg per hour for 6 hours, N = 20); (2) group TA (loading dose 15 mg/kg, continuous infusion 1 mg/kg per hour for 6 hours, N = 20); (3) control group (infusion of normal saline for 6 hours, N = 19). RESULTS Treatment groups were similar preoperatively. No significant difference in intraoperative blood loss or perioperative use of blood products was noted. D-dimer concentration was elevated in the control group compared to the EACA and TA groups (p < 0.05). Group TA had less postoperative blood loss than the EACA and control groups at 6 and 12 hours postoperatively (p < 0.05). TA had reduced total blood loss (600 +/- 49 mL) postoperatively compared to EACA (961 +/- 148 mL) and control (1060 +/- 127 mL, p < 0.05). CONCLUSION TA and EACA effectively inhibited fibrinolytic activity intraoperatively and throughout the first 24 hours postoperatively. TA was more effective in reducing blood loss postoperatively following CABG. This suggests that TA may be beneficial as an effective and inexpensive antifibrinolytic in first-time CABG patients.
Microfluidic serial digital to analog pressure converter for arbitrary pressure generation and contamination-free flow control

Multilayer microfluidics based on PDMS (polydimethylsiloxane) soft lithography have offered parallelism and integration for biological and chemical sciences, where reduction in reaction volume and consistency of controlled variables across experiments translate into reduced cost, increased quantity and quality of data. One issue with push up or push down microfluidic control concept is the inability to provide multiple control pressures without adding more complex and expensive external pressure controls. We present here a microfluidic serial DAC (Digital to Analog Converter) that can be integrated with any PDMS device to expand the device's functionality by effectively adding an on-chip pressure regulator. The microfluidic serial DAC can be used with any incompressible fluids and operates in a similar fashion compared to an electronic serial DAC. It can be easily incorporated into any existing multilayer microfluidic devices, and the output pressure that the device generates could be held for extensive times. We explore in this paper various factors that affect resolution, speed, and linearity of the DAC output. As an application, we demonstrate microfluidic DAC's ability for on-chip manipulation of flow resistance when integrated with a simple flow network. In addition, we illustrate an added advantage of using the microfluidic serial DAC in preventing back flow and possible contamination.
Use of Antimicrobial Agents in Animal Feeds: Implications for Human Health

The inclusion of subtherapeutic doses of antimicrobial agents in animal feed is credited for having contributed to lower costs of meat, milk, and eggs. The practice often is associated with the acquisition of resistant enteric flora by the involved animals, a phenomenon that in turn may contribute to the human reservoir of coliforms and salmonellae resistant to antimicrobial agents. Farm workers may transiently acquire resistant intestinal flora and on rare occasions develop salmonellosis. Although irrefutable evidence of the growth-promoting properties of antibiotics in animal feed was provided 30-40 years ago, additional studies--with a focus on mechanisms of the effect--are presently needed. It may be possible to identify factors effective in promoting growth without deleterious effects on the intestinal flora. A national program of surveillance of antimicrobial administration (in both subtherapeutic and therapeutic doses) to food-producing animals should be established. Molecular epidemiologic research efforts must be undertaken to determine whether genetic information of animal origin contributes significantly to the human environmental pool of antimicrobial resistance. In the meantime, it does not appear that the banning of drugs as feed additives, with concomitant unrestricted use of these agents for the treatment of both animals and people, would favorably influence the problems of antimicrobial resistance and salmonellosis in human populations.
Setting safety leadtimes for purchased components in assembly systems

We consider the problem of setting appropriate safety leadtimes in an assembly system where all components are purchased and the only manufacturing operation is final assembly. First, we describe two formulations of this problem: (1) minimize total inventory carrying and tardiness costs and (2) minimize inventory carrying costs subject to a service constraint. Second, we discuss how these formulations sometimes fail to adequately provide a decision maker with sufficient information to establish leadtimes when applied independently but how they can be used together to provide a useful decision support system. Finally, we describe a procedure similar to ABC analysis that allows us to solve a much smaller related problem whose solution provides a good approximation to the solution of the original problem. We conclude the paper with numerical examples and a discussion of an actual implementation.
Potentiometric determination of silver with dithiooxamide

Abstract Potentiometric titration with dithiooxamide solution can be used to determine silver in the 0.0100–50.0 p.p.m range with an average accuracy of ca . 0.5% and a relative standard deviation ranging from 1.26% to 0.03% The metals commonly associated with silver can be masked with fluoride and EDTA The advantages of the method over other potentiometric and common spectrophotometric methods are outlined.
Synthesis and Synchrotron Microcrystal Structure of an Aluminophosphate with Chiral Layers Containing Λ Tris(ethylenediamine)cobalt(III)

A chiral aluminophosphate, d-Co(en)3·Al3P4O16·3H2O, has been synthesized using optically pure d-Co(en)33+ as a templating agent (en = 1,2-diaminoethane). The structure of the material has been determined from a small single crystal using synchrotron radiation and imaging plate detection. The aluminophosphate contains chiral macroanionic sheets similar to those previously reported in trans-Co(dien)2·Al3P4O16·xH2O (dien = diethylenetriamine). Co(C2N2H8)3·Al3P4O16·3H2O, Mr = 754.1, orthorhombic, C2221, a = 8.502(6) A, b = 14.620(6) A, c = 20.890(11) A, V = 2597(3) A3, Z = 4, ρcalc = 1.929 g cm-3, ρobs = 1.95 g cm-3, λ = 1.2007(5) A, μ = 9.389 mm-1, F(000) = 1526, T = 293 K, RF = 0.084 for 872 reflections I > 2σ(I).
Material and device considerations for organic thin-film transistor sensors

The rapid development of the field of organic electronics has sparked great interest in the use of organic thin-film transistors (OTFTs) as low-cost electronic sensors. The direct coupling of the electronic and the sensor media to provide real time electrical output has already demonstrated high sensitivity to a variety of chemical species. The synthetic versatility of organic materials also provides endless routes to impart functionality for specifically targeted chemical interactions. Owing to their compatibility with flexible materials and simple fabrication methods, OTFTs are poised to have a tremendous impact on future portable detection technology. This article reviews recent progress made toward improved sensitivity, selectivity and stability of OTFT sensors through material and device engineering. Specific consideration is paid to the interaction of the electronic materials with the analytes as a means of providing insight into mechanistic principles as well as the future direction of OTFTs.
Deformation during terrane accretion in the Saint Elias orogen, Alaska

The Saint Elias orogen of southern Alaska and adjacent Canada is a complex belt of mountains formed by collision and accretion of the Yakutat terrane into the transition zone from transform faulting to subduction in the northeast Pacific. The orogen is an active analog for tectonic processes that formed much of the North American Cordillera, and is also an important site to study (1) the relationships between climate and tectonics, and (2) structures that generate large- to great-magnitude earthquakes. The Yakutat terrane is a fragment of the North American plate margin that is partly subducted beneath and partly accreted to the continental margin of southern Alaska. Interaction between the Yakutat terrane and the North American and Pacific plates causes significant differences in the style of deformation within the terrane. Deformation in the eastern part of the terrane is caused by strike-slip faulting along the Fairweather transform fault and by reverse faulting beneath the coastal mountains, but there is little deformation immediately offshore. The central part of the orogen is marked by thrusting of the Yakutat terrane beneath the North American plate along the Chugach–Saint Elias fault and development of a wide, thin-skinned fold-and-thrust belt. Strike-slip faulting in this segment may be localized in the hanging wall of the Chugach–Saint Elias fault, or dissipated by thrust faulting beneath a north-northeast–trending belt of active deformation that cuts obliquely across the eastern end of the fold-and-thrust belt. Superimposed folds with complex shapes and plunging hinge lines accommodate horizontal shortening and extension in the western part of the orogen, where the sedimentary cover of the Yakutat terrane is accreted into the upper plate of the Aleutian subduction zone. These three structural segments are separated by transverse tectonic boundaries that cut across the Yakutat terrane and also coincide with the courses of piedmont glaciers that flow from the topographic backbone of the Saint Elias Mountains onto the coastal plain. The Malaspina fault–Pamplona structural zone separates the eastern and central parts of the orogen and is marked by reverse faulting and folding. Onshore, most of this boundary is buried beneath the western or “Agassiz” lobe of the Malaspina piedmont glacier. The boundary between the central fold-and-thrust belt and western zone of superimposed folding lies beneath the middle and lower course of the Bering piedmont glacier.
Career Information for Statistics Graduate Students

Abstract A method is proposed for statistics graduate student self-assessment of appropriateness for public, private, or academic workplace.
Merton H. Miller: Memories of a Great Mentor and Leader

MERTON MILLER WAS A WORLD LEADER. Merton Miller was a renowned academic mentor. He was our champion. In my view, Merton was our Leonardo da Vinci. Merton's genius defined the field of financial economics. He was a visionary, a man of intense curiosity, with a willingness to embrace ambiguity and use his brilliant intuition throughout his illustrious research career to overturn a multitude of long-held "truths." Merton's research shows the same grace that Merton showed himself. He always tested knowledge and used his love of science, logic, art, literature, and music as a balance to create knowledge. Merton's research exhibits a marvelous interconnectedness to once seemingly unrelated ideas. He has left us a research legacy that will be treasured for generations to come. Discussing ideas with Merton, whether at the lunch table at the Faculty Club or in a car going to a downtown class, or at dinner afterwards, or the myriad times you would meet up with him at some foreign conference or in his or your office working on a research paper, was always inspiring or synergistic. He had so many ideas. He was easily able to marry your ideas with his own, and new and exciting ideas followed on, one after the other. This was a purely fun, invigorating, draining to some extent, but nevertheless, an intoxicating experience. I remember the many hours that we spent together and I smile. To interact with a genius is a wonderful gift. In looking back, I realize that Merton used all of his cortical skills to innovate. Not only did he use logic, mathematics, and economics, but also the arts, vivid pictures, feelings, and emotions. His many wonderful stories and illustrations, the pictures he drew in discussions, the diversions helped all of us who interacted with him to create, imagine more, and grow in our own understanding. He was a true teacher. He had an uncanny ability to excite you in solving problems or in the classroom, yet totally relax you with his warm demeanor and generosity.
β-lactam ring rearrangement of a 6-sulfeniminopenicillanic acid

Abstract Reaction of a 6-sulfeniminopenicillanic acid ester with diazomethane induces a β-lactam ring expansion rearrangement which proceeds via methylene insertion into the C(6)-C(7) bond.
Intergranular vs transgranular stress corrosion cracking of Cu 30-Au

The mechanism of transgranular stress corrosion cracking (TGSCC) that was proposed by Edeleanu and Forty and Sieradzki and Newman recognized an often neglected aspect of TGSCC, namely, the brittle, cleavage-like appearance of the fracture surface. In this paper it is suggested that anodic processes produce a surface layer that induces cleavage of the normally ductile substrate. Demonstrated in experiments by Newman et al. on thin foils of {alpha}-brass. Foils that were fractured at 77{degrees}K without prior corrosion failed in a ductile manner as did foils that were corroded, dried, and then fractured in air. Thus, brittle fracture did to occur merely as a result of immersion in the aqueous solution, nor did it occur simply as a result of deformation at low temperature. In fact, failure occurred by local fracture at the surface where the alloy reacted with the environment followed by brittle crack propagation through the normally ductile substrate.
Electrical Resistivity Changes in Saturated Rock under Stress

Electrical resistivity of water-saturated crystalline rock such as granite, diabase, dunite, or quartzite changes by an order of magnitude prior to fracture of the rock in compression. The effect observed even under high confining pressure is due to formation of open cracks which first appear at one-third to two-thirds the fracture stress.
19F, 13C single- and two-bond 2D NMR correlations in perfluoroheptanoic acid

The first 19F, 13C single- and multi-bond 2D NMR correlations using fluorine detection methods are reported for a perfluorinated alkyl chain. These heteronuclear correlations are observed in perfluoroheptanoic acid and combined with 19F-decoupled 13C data and homonuclear 19F, 19F COSY to derive a full set of unequivocal 19F and 13C assignments.
Methodology for Lung Cancer Evidence Review and Guideline Development: ACCP Evidence-Based Clinical Practice Guidelines (2nd Edition)

Background To assemble a geographically diverse panel of experts in the diagnosis and treatment of lung cancer, representative of multiple clinical specialties, with the intention of developing clinically relevant practice guidelines for chest medicine and primary care physicians, including recommendations covering the full spectrum of care of the patient with non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Methods The Duke University Center for Clinical Health Policy Research was selected to review and summarize the current evidence in the treatment of NSCLC. The BlueCross BlueShield Association Technology Evaluation Center was chosen and funded by the Agency for Healthcare Research and Quality to review and synthesize the current evidence on treatment of SCLC. Other chapters received existing guidelines, systematic reviews, and metaanalyses that were published since the first edition of these guidelines, as collected by the Duke University Evidence-based Practice Center. The writing committees for these chapters conducted searches for the primary articles and additional evidence in their topic area. The expert panel established clinical recommendations founded on the synthesis of this evidence. Conclusions This section describes the approach used to develop the guidelines, including identifying, evaluating, and synthesizing the evidence, assessing the strength of evidence and grading the individual recommendations, and suggestions for implementation of the guidelines.
Purification of a DFP-hydrolyzing enzyme from squid head ganglion.

Abstract An enzyme which hydrolyzes DFP and similar organophosphorus compounds has been purified 1300-fold from squid head ganglion. This enzyme which we term squid nerve DFPase is markedly different from previously reported DFPases from mammalian and microbial sources. The enzyme shows marked selectivity with respect to substrates, permitting some speculation about the nature of its active site. A striking feature of squid nerve DFPase is its relative limitation to cephalopod nerve. Available evidence suggests that a similar distribution may exist for isethionate, the major anion in squid nerve. This tentative parallel between DFPase and isethionate raises the possibility of a function for squid nerve DFPase.
Inhibitory Action of Ethanol on Luteinizing Hormone Secretion by Rat Anterior Pituitary Cells in Culture

Ethanol (EtOH) inhibits LH secretion in humans and animals. In these studies we examined the gonadotroph as a possible site of action of EtOH by treating cultured pituitary cells with several concentrations of EtOH (200, 400, or 800 mg/100 ml) for 4 days. Cells were incubated for 2 h with LHRH on the last day of the experiment. Whereas basal LH release was unaffected over the 4 days of EtOH treatment, the LH response to LHRH was inhibited by EtOH in a dose-related fashion. Inhibitory responses at the lowest concentration of EtOH (200 mg/100 ml) occurred inconsistently. At the highest concentration (800 mg/100 ml), the curve of log LHRH dose vs. LH release had a lower maximum and was shifted to the right of that for untreated cells. Total LH content and total number of cells attached to the culture wells were unchanged after EtOH treatment. These data suggest that EtOH at high concentrations can lower the responsiveness of the gonadotroph to LHRH. (Endocrinology 120: 849–852, 1987)
What do complex spikes signal about limb movements

: Deciphering the information or signals carried by the complex spike discharge of Purkinje cells has proven to be problematic, primarily because of low frequency discharge and lack of adequate analytical techniques. This problem is particularly acute for studies of limb movements. To this end the relationship of cerebellar Purkinje cell complex spike discharge to direction and speed were studied in a manual-tracking task. Two monkeys were trained to pursue track targets moving in one of eight directions and at one of four speeds. An analysis based on Poisson regression modeling fitted the complex spike counts during single movement trials to target direction and/or speed. Using single trial data, the Poisson modeling demonstrated that the complex spike discharge for a majority of the Purkinje cells was significantly fit to tracking direction and speed. A second analysis based on the directional distribution of position and speed errors and a Poisson regression model of complex spike discharge to tracking position and speed errors found little relationship to movement error. Comparison of the preferred direction of the complex spike discharge with that of the simple spike activity revealed a reciprocal relationship for many cells. Thus, the complex spike discharge signals both tracking direction and speed but not movement errors. Furthermore, treating complex spike counts as a Poisson process provides a powerful tool for analyzing these events in single trials, without the need for extensive averaging.
Apoplastic pH and inorganic ion levels in tomato fruit: A potential means for regulation of cell wall metabolism during ripening

Apoplastic pH and ionic conditions exert strong influence on cell wall metabolism of many plant tissues; however, the nature of the apoplastic environment of ripening fruit has been the subject of relatively few studies. In this report, a pressure-bomb technique was used to extract apoplastic fluid from tomato fruit (Lycopersicon esculentum Mill.) pericarp at several developmental stages. pH and the levels of K + , Na + , Ca 2+ , Mg 2+ , Cl - and P were determined and compared with the values for the bulk pericarp and locule tissues. The pH of the apoplastic fluid from pericarp tissue decreased from 6.7 in immature and mature-green fruits to 4.4 in fully-ripe fruit. During the same period, the K + concentration increased from 13 to 37 mM. The levels of Na + and divalent cations did not change, whereas the anions P and Cl - increased in ripe fruit. Ca 2+ levels remained relatively constant during ripening at 4-5 mM, concentrations that effectively limit pectin solubilization. The electrical conductivity of the apoplastic liquid increased 3-fold during ripening, whereas osmotically active solutes increased 2-fold. Pressure-treated fruit retained the capacity to ripen. The decline in apoplastic pH and increase in ionic strength during tomato fruit ripening may regulate the activity of cell wall hydrolases. The potential role of apoplastic changes in fruit ripening and softening is discussed.
Vaporization characteristics of carbon heat shields under radiative heating.

Study of the vaporization characteristics of samples of ATJ graphite, a material that has been considered for use on a Jovian probe. These samples were subjected to radiative heating loads of approximately 2 kW/sq cm in argon atmospheres of pressures from 0.00046 to 1 atm. Surface temperatures, mass loss rates, and spatially resolved emission spectral data were recorded. These data are analyzed to determine carbon vapor pressure as a function of temperature and are compared with current models for the vapor pressure of carbon. The effects of finite vaporization (i.e., nonequilibrium) rates are considered and compared with experiment. Estimates of the heat of vaporization from an energy balance are also presented.
Reactivity of ternary chalcogenides

Abstract The intercalation chemistry of some layered ternary chalcogenides has been investigated. The reaction of n-butyllithium with Ta2NiSe5 and Ta2PdSe6 affords the compounds Li2Ta2NiSe5 and LiTa2PdSe6. X-ray powder diffraction data are indicative of significant structural changes upon intercalation. The addition of Cu to the NbPdS system has produced the compound Nb2Pd0.74Cu0.22S5. This compound has been characterized by single-crystal X-ray diffraction methods ( monoclinic , C 3 2h  C 2/ m , a = 12.208(6), b = 3.286(2), c = 14.851(8) A , β = 101.27(2)° ). The compound is part o f an isomorphous series of nonstoichiometric metallic conductors with the Nb2Pd0.71Se5 structure, but it differs from its congeners in having Cu atoms in between the layers. The structural chemistry and reactivity associated with the van der Waals' region in these ternary compounds is compared with that of the binary Nb and Ta chalcogenides.
Research at the margin: mapping masculinity and mobility of African‐American high school dropouts

Research on the intersection of racial and gender identities is important in understanding the processes of school engagement. This article focuses on how African‐American male adolescents move in and out of schooling and make sense of those experiences. By examining how they construct meanings of masculinity a textured and complex trajectory of schooling is captured. Using qualitative data from a group of African‐American male high‐school dropouts who participated in a national alternative high school program, the author highlights the nuances of racial and gendered identities and their consequences for schooling experiences and outcomes. The results uniquely highlight and map the social mobility between contested traditional and alternative schooling spaces by uncovering these young men’s personal pathways of reflection, regret and social redemption.
Mitochondrial physiology of diapausing and developing embryos of the annual killifish Austrofundulus limnaeus: implications for extreme anoxia tolerance

Diapausing embryos of the annual killifish Austrofundulus limnaeus have the highest reported anoxia tolerance of any vertebrate and previous studies indicate modified mitochondrial physiology likely supports anoxic metabolism. Functional mitochondria isolated from diapausing and developing embryos of the annual killifish exhibited VO2, respiratory control ratios (RCR), and P:O ratios consistent with those obtained from other ectothermic vertebrate species. Reduced oxygen consumption associated with dormancy in whole animal respiration rates are correlated with maximal respiration rates of mitochondria isolated from diapausing versus developing embryos. P:O ratios for developing embryos were similar to those obtained from adult liver, but were diminished in mitochondria from diapausing embryos suggesting decreased oxidative efficiency. Proton leak in adult liver corresponded with that of developing embryos but was elevated in mitochondria isolated from diapausing embryos. In metabolically suppressed diapause II embryos, over 95% of the mitochondrial oxygen consumption is accounted for by proton leak across the inner mitochondrial membrane. Decreased activity of mitochondrial respiratory chain complexes correlates with diminished oxidative capacity of isolated mitochondria, especially during diapause. Respiratory complexes exhibited suppressed activity in mitochondria with the ATP synthase exhibiting the greatest inhibition during diapause II. Mitochondria isolated from diapause II embryos are not poised to produce ATP, but rather to shuttle carbon and electrons through the Kreb’s cycle while minimizing the generation of a proton motive force. This particular mitochondrial physiology is likely a mechanism to avoid production of reactive oxygen species during large-scale changes in flux through oxidative phosphorylation pathways associated with metabolic transitions into and out of dormancy and anoxia.
On the impact of soft hand-off in cellular systems

We present a model for soft, hand-off in wireless cellular networks. In such networks, due to overlapping cells, hand-offs are not instantaneous and multiple channels may be occupied by a single mobile for a non-zero freeze time period.We provide a mathematical model of wireless cellular networks with soft hand-offs. We examine different performance measures and show that freeze time may have a major impact on the system performance if the mobility rate is not negligible. Both exact and approximate formulations are given. Different fixed-point approximation methods are used to reduce the complexity of the exact solution. Various performance measures such as new and hand-off blocking and probability of a call dropout are carefully examined.
Wheat Protein Premiums and Price Differentials

supply shifter for a product is the price of its closest substitute. Frequently, the substitute is a different quality, grade, or brand of the same commodity. (Tomek and Robinson provide a useful discussion on price differences, pp. 134-43.) These differences cannot be examined in empirical work where aggregate functions rather than separate, closely related functions are estimated. The research reported in this note investigates the relationships between different qualities of a commodity, adding to the sparse body of empirical work on this topic. A Lancaster "product characteristics" approach is used in differentiating classes of wheat by their protein content characteristic.1 The specific objective is to generate a simple statistical model for analyzing the effect of changes in available supplies of wheat of various protein content on their relative prices. Prediction rather than complete behavioral understanding is the goal. Historically, high protein wheats have been relatively scarce, bringing a higher price than lower protein wheats. The price differential is commonly called a "protein premium." The amount of premium for wheats of various protein content varies in response to changing supplies of, and demand for, the protein component of wheat. Demand for high protein wheat is derived from the demand for bread. The demand for low protein wheat is derived from the demand for biscuits, cakes and pastries, and livestock products.2 Occasionally, little or no premium is paid for protein. This occurred, for example, during several months in 1972, 1973, and 1974, a period when U.S. exports soared. Earlier research to investigate a possible negative impact of exports on protein premia found that supply factors were associated with much of the variability in the premia (Ryan and Bale, p. 31). Accordingly, this note focuses on the role of supply factors on relative price movements. Protein is regarded as the differentiating characteristic in wheat. Since the object of this note is to estimate price variations, two price dependent functions of wheats of two different protein contents are specified. The quantity supplied of each commodity is assumed to be predetermined. No short-run supply response is possible because productio and carry-in stocks are determined in the previous time period. Only one demand shifter is explicitly specified for each function-the quantity of the major competing wheat. From the two price dependent functions, one function is formed for estimation, equation (1). The dependent variable is a ratio of the prices of the wheats. The price ratio defines protein premium rather than the more usual definition of price differences (Hyslop). We prefer a price ratio, since it avoids the need to deflate prices. The ratio can, of course, be converted to an absolute difference at any given level of either price:
Pionic and radiative decay widths of charmed hadrons in a badly broken SU(4) symmetry

Abstract On the basis of current algebras and duality a general rule is proposed to introduce large breaking of a higher symmetry into decay rates. The rule is applied to charmed meson decays. We also derive an upper bound on the D 0∗ → D 0 +π 0 decay rate which is used to set a lower bound on its Q value.
Traumatic central cord syndrome: results of surgical management.

Object. The authors compare clinical outcomes demonstrated in patients with traumatic central cord syndrome (CCS) who underwent early ( 24 hours after injury) surgery. Methods. The clinical characteristics, radiographic findings, surgery-related results, length of hospital stay (LOS), and clinical outcomes obtained in 50 patients with surgically treated traumatic CCS were reviewed retrospectively. Shorter intensive care unit (ICU) stay and LOS were observed in all patients who underwent early surgery compared with those who underwent late surgery. In patients with CCS secondary to acute disc herniation or fracture/dislocation who underwent early surgery significantly greater overall motor improvement was observed than in those who underwent late surgery (p = 0.04). Overall motor outcome in patients with CCS secondary to spinal stenosis or spondylosis who underwent early surgery was not significantly different from that in those who underwent late surgery (p = 0.51). Wors...
Shear viscosity, extensional viscosity, and die swell of polypropylene in capillary flow with pressure dependency

The shear and extensional viscosities of a polypropylene resin were studied using a capillary rheometer and capillary dies of 1-mm diameter and length of 10, 20, and 30 mm. Melt temperatures at 190, 205, and 220°C and shear rates between 100 and 5000 s−1 were used. At the highest shear rate a visible melt fracture was observed. An equation relating the pressure drop and die length was derived with consideration of pressure effects on melt viscosities and the end effect. After the correction for pressure effects the true wall shear stress and end effect at zero pressure were calculated. The end effect showed a critical stress of melt fracture around 105 Pa, and increased rapidly when shear stress increased above the critical stress. From shear stress the shear viscosity was calculated, and a power law behavior was observed. Extensional viscosity was calculated from the end effect and showed a decreasing trend when strain rate increased. After time–temperature superposition shift shear viscosity data correlated well, but an upward trend was observed in extensional viscosity when melt fracture occurred. Die swell ratio at different temperatures can be plotted as a function of wall shear stress and was higher for shorter dies. © 2002 Wiley Perioodicals, Inc. J Appl Polym Sci 84: 1269–1276, 2002; DOI 10.1002/app.10466
Role of Hydrogen in Stabilizing New Hydride Phases or Altering Old Ones

Abstract The role of hydrogen impurities in many of the more active metals in the formation of ternary compounds has often not been considered or recognized when these reactants do not contain significant metal hydride phases. This is a particular problem because most phase identifications or structure determinations have traditionally depended on X-ray diffraction means. Extended investigations have established that the alkaline-earth metals, plus some other divalent metals, have evidently often contributed substantial amounts of hydrogen, and this feature has led to numerous erroneous reports of supposed binary phases that form with the main-group (p) elements. Methods of detection and some ready means to avoid these problems will be described. The particularly serious examples that occur among phases reported with β-Yb 5 Sb 3 , Mn 5 Si 3 , and Cr 5 B 3 -type binary structures for pnictogen (As–Bi) and tetrel (Si–Pb) elements are detailed for 32 examples. Fluoride has proven to be useful as a stand-in for hydride in a variety of these systems.
First Scale-Up Synthesis of WAY-262398, a Novel, Dual-Acting SSRI/5HT1a Antagonist

An alternative synthesis of WAY-262398, 1, a novel, dual-acting SSRI/5-HT1A antagonist, has been developed. The target compound was initially synthesized as a part of diastereomeric mixture which was separated by chiral preparative HPLC. The new route was designed around intermediates suitable for chiral resolution and/or chiral reduction of a suitable intermediate. Both processes had to be employed to achieve the target optical purity.
Utility of whole-hand input

Using a design method for whole-hand input developed by the authors, the teleoperation of a six-legged mobile robot with manipulator arms has been simulated. Evaluations of three different control structures compare performance between conventional input, exemplified by a set of dials, and whole-hand input using a VPL DataGlove. The evaluations reveal a range of appropriate use of whole-hand input compared to conventional input. In the first example, whole-hand input is superior, in the second, whole-hand input provides performance on par with conventional devices, and in the last, whole-hand input is inferior to conventional devices.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.