cssi/SciSciGPT-SciSciNet huggingface dataset:
Spatial collision resolution for packet-switched multiple-access wireless networks

A collision resolution scheme that accounts for the spatial aspects of co-channel interference is analyzed for multiple access packet communications with application in intelligent vehicle highway systems (IVHS). In wireless networks with interacting base stations, co-channel interference and collisions are diminished by using discontinuous transmissions and coordination: a base station is silenced (or power-controlled) by a neighboring station in order to improve the latter's chance of successful transmission and decrease retransmission attempts. The performance of this spatial collision resolution scheme is studied with a priori knowledge packet capture probabilities. >
Risk and vulnerability : the forward looking role of social protection in a globalizing world

The paper outlines a forward-looking role of social protection against the background of increasing concerns about risk, and vulnerability, exemplified by the recent East Asian crisis, the concerns of the World Development Report (WDR) 2000, the need for a better understanding of poverty dynamics, and the opportunity and risks created by globalization. These considerations, and the need for a more proactive approach to lasting poverty reduction, have led to the development of a new conceptual framework, which casts social protection as social risk management. The paper highlights the main elements of the new conceptual framework, and its main strategic conclusions for attacking poverty, before addressing crucial issues for its implementation: the need for an operational definition of vulnerability; the use of social risk assessments as an operational entry point for a new policy dialogue; economic crisis management, and the lessons for social protection; and, the undertaking of social expenditure reviews to enhance the effectiveness of government intervention for addressing risk and vulnerability. The pilot experience with some of these elements, yields cautious optimism that a promising road for addressing poverty has been found.
Molecular mechanism for familial protein C deficiency and thrombosis in protein CVermont (Glu20-->Ala and Val34-->Met).

The role of two protein C gamma-carboxyglutamic acid domain mutations in familial thrombosis, protein CVermont (Bovill, E. G., Tomczak, J. A., Grant, B., Bhushan, F., Pillemer, E., Rainville, I.R., and Long, G. L. (1992) Blood 79, 1456-1465), was investigated. Two single mutations (Glu20-->Ala and Val34-->Met) and the naturally occurring double mutation were created by site-directed mutagenesis and were expressed in human kidney 293 cells. Purified recombinant protein C with the mutation glutamate to alanine at position 20 is defective in the assays of activated partial thromboplastin time, factor Va inactivation, and fibrinolysis. Mutation from valine to methionine at position 34 has only a minor effect. Activation of Glu20 mutants by thrombin-thrombomodulin was not enhanced by phospholipid vesicles and showed a different calcium dependence compared with the wild type, suggesting that Gla20 is important in the interaction of the protein C Gla domain with a phospholipid-mediated site on the thrombomodulin molecule. Glu20-substituted protein C is not inhibited by calcium ion in its interaction with the calcium-dependent monoclonal antibody H-11, suggesting that this mutation has lost the calcium-induced, lipid-independent conformational transition of the protein C Gla domain. These data indicate that the loss of Gla20 causes the major familial dysfunction of protein C to associate with phospholipid as well as to undergo Ca(2+)-dependent, lipid-independent conformational changes and are consistent with the importance of Gla20 in both external and internal Ca2+ binding based upon the x-ray-derived structure of the homologous Gla domain in bovine prothrombin.
Treatment of Endamebiasis

Excerpt The introduction of ipecac and its derivations of various emetin compounds was thought to be the solution of a difficult therapeutic problem. With the passage of time ipecac and emetin have...
Expressiveness and Voting

It has been suggested that voting may be an ``expressive''action taken without regard to any hope of actuallyinfluencing election outcomes on the margin. However, therehas been no real-world evidence brought to bear on thequestion of whether the propensity of an individual to voteand the propensity of that same individual to engage in otherforms of ``expressive'' behavior are correlated in anystatistically meaningful sense. Drawing from longitudinal datafound in the National Election Surveys we report compellingevidence of a strong, positive relationship between what weterm ``political expressiveness'' and the act of voting.
Anatomy of the myenteric plexus of the opossum esophagus.

Abstract Silver-impregnated stretch preparations of the opossum esophageal body and lower esophageal sphincter were compared as to the general aspect of the plexus, density of perikarya and ganglia, type and size of ganglia, nerve bundle diameter, density of nerve bundle intersections, and relations between ganglia and nerve bundle intersections. Density of perikarya and ganglia, but not density of nerve bundle intersections, declined along the esophagus, with a nadir at the sphincter. The proximal body contained 960–1358 perikarya/cm2 and the sphincter, 70–333 perikarya/cm2. Ganglia contained 3–100 cells, 54% having
It is Only a Test! [AP-S Turnstile]

This is the time of the year when I riffle through the material gathered from various print and online sources and fi led for possible future use in my columns. Some of the recent items from my collection are featured in this short quiz. So, take out a pen and start marking your choices. The answers appear elsewhere in this issue. I hope you find the quiz both amusing and instructive. Good luck!
Nonionic surface-active compounds. XI. Micellar size, shape, and hydration from light-scattering and hydrodynamic measurements

Light-scattering and hydrodynamic measurements on three polyoxyethylated lauryl alcohols have been interpreted as leading to the conclusion that the smallest micelles are the most heavily hydrated (in terms of moles of water per ethylene oxide oxygen), and that hydration decreases as the micellar size increases. For small micelles, with an aggregation number, n, less than about 100, the hydration is in the range 2.5–4.0 molecules of water, and the micelle has the shape of a oblate ellipsoid. For 100 < n < 150, the hydration falls to about 0.5, and the micelle is spherical. Above n = 150 the hydration gradually falls to zero, while the micelle assumes the form of a prolate ellipsoid. It is also concluded that the molecules making up the micelle are arranged in a longitudinal “log-boom” structure rather than in the radial “sausage” proposed by Debye.
Spectral zone selection methodology for pebble bed reactors

A methodology is developed for determining boundaries of spectral zones for pebble bed reactors. A spectral zone is defined as a region made up of a number of nodes whose characteristics are collectively similar and that are assigned the same few-group diffusion constants. The spectral zones are selected in such a manner that the difference (error) between the reference transport solution and the diffusion code solution takes a minimum value. This is achieved by choosing spectral zones through optimally minimizing this error. The objective function for the optimization algorithm is the total reaction rate error, which is defined as the sum of the leakage, absorption and fission reaction rates errors in each zone. The selection of these spectral zones is such that the core calculation results based on diffusion theory are within an acceptable tolerance as compared to a proper transport reference solution. Through this work, a consistent approach for identifying spectral zones that yield more accurate diffusion results is introduced.
Benzo[b] thiophene derivatives. XXII. Synthesis of the isomeric 5-methyl-6-methoxy- and 5-methoxy-6-methylbenzo[b] thiophene-2-carboxylic acids†

The two isomeric benzo[b] thiophene-2-carboxylie acids having methyl and methoxy groups at positions 5 and 6 have been prepared and characterized. Both acids have been decarboxylated to the corresponding isomeric 5,6-disubstituted benzo[b]thophenes, and esterified to their methyl esters. The intermediate rhodanines, α-mercaptocinnamic acids and corresponding disulfides are described. An unusual by-product in the oxidative cyclization of β-3-methyl-4-methoxyphenyl-α-mercaptoacrylic acid with iodine is shown to be trans-3-methyl-4-methoxycinnamic acid, which can also be formed directly from the mercaptoacrylic acid by reduction with hydrogen iodide.
The consistency of the swallowing technique in determining occlusal vertical relation in edentulous patients

Abstract A roentgenographic cephalometric investigation was conducted on 20 subjects to evaluate the swallowing technique for determining the occlusal vertical relation in edentulous patients. The findings were: 1. 1. The occlusal face height after prosthetic treatment showed an increase ranging between 0 and 5 mm., with a mean increase of 2.8 mm., as compared to occlusal face height before the extraction of the teeth. This increase was statistically significant. 2. 2. A significant correlation was found between the number of posterior teeth missing before extraction and the increase in occlusal face height as determined by the swallowing technique after the patients became edentulous. 3. 3. The swallowing technique presented a direct approach to the problem of establishing the occlusal vertical dimension in edentulous patients. The technique described in this article is recommended as a reliable method for establishing the occlusal vertical jaw relation of edentulous patients.
Resistance to pyraclostrobin, boscalid and multiple resistance to Pristine® (pyraclostrobin + boscalid) fungicide in Alternaria alternata causing alternaria late blight of pistachios in California

Pristine® (pyraclostrobin + boscalid) is a fungicide registered for the control of alternaria late blight in pistachio. A total of 95 isolates of Alternaria alternata collected from orchards with and without a prior history of Pristine® sprays were tested for their sensitivity towards pyraclostrobin, boscalid and Pristine® in conidial germination assays. The EC50 values for 35 isolates from orchards without Pristine® sprays ranged from 0·09 to 3·14 µg mL−1 and 100 µg mL−1. Among 59 isolates from the orchard with a history of Pristine® sprays, 56 were resistant to pyraclostrobin; only two were sensitive (EC50 < 0·01 µg mL−1) and one was weakly resistant (EC50 = 10 µg mL−1). For the majority of these isolates EC50 values ranged from 0·06 to 4·22 µg mL−1 for boscalid and from 0·22 to 7·74 µg mL−1 for Pristine®. However, seven isolates resistant to pyraclostrobin were also highly resistant to boscalid and Pristine® and remained pathogenic on pistachio treated with Pristine®. Whereas strobilurin resistance is a common occurrence in Alternaria of pistachio, this is the first report of resistance to boscalid in field isolates of phytopathogenic fungi. No cross resistance between pyraclostrobin and boscalid was detected, suggesting that Pristine® resistance appears as a case of multiple resistance.
Targeted ablation of beta cells in the embryonic zebrafish pancreas using E. coli nitroreductase.

Abstract In order to generate a zebrafish model of β cell regeneration, we have expressed an Escherichia coli gene called nfsB in the β cells of embryonic zebrafish. This bacterial gene encodes a nitroreductase (NTR) enzyme, which can convert prodrugs such as metronidazole (Met) to cytotoxins. By fusing nfsB to mCherry , we can simultaneously render β cells susceptible to prodrug and visualize Met dependent cell ablation. We show that the neighboring α and δ cells are unaffected by prodrug treatment and that ablation is β cell specific. Following drug removal and 36 h of recovery, β cells regenerate. Using ptf1a morphants, it is clear that this β cell recovery occurs independently of the presence of the exocrine pancreas. Also, by using photoconvertible Kaede to cell lineage trace and BrdU incorporation to label proliferation, we investigate mechanisms for β regeneration. Therefore, we have developed a unique resource for the study of β cell regeneration in a living vertebrate organism, which will provide the opportunity to conduct large-scale screens for pharmacological and genetic modifiers of β cell regeneration.
Real-time visualization of domain formation in periodically poled lithium niobate

We present video footage demonstrating real-time visualization of domain formation in periodically-poled lithium niobate (PPLN). This in-situ, non-destructive technique provides important visual information concerning the global quality and dynamics of domain patterning during the fabrication of PPLN.
The effect of food on the relative bioavailability of rapidly dissolving immediate-release solid oral products containing highly soluble drugs.

The purpose of this study is to test the hypothesis that rapidly dissolving immediate-release (IR) solid oral products containing a highly soluble and highly permeable drug [biopharmaceutical classification system (BCS) class I] are bioequivalent under fed conditions. Metoprolol and propranolol (BCS class I) as well as hydrochlorothiazide (BCS class III) were selected as model drugs. The relative bioavailability of two FDA approved (Orange Book AB rating) solid oral dosage forms of metoprolol and propranolol/hydrochlorothiazide (combination tablets) was evaluated in human volunteers under fed conditions using a two-way crossover design. Equal numbers of male and female volunteers were recruited, and racial and/or ethnic minorities were not excluded. The plasma concentrations of metoprolol, propranolol, and hydrochlorothiazide were determined using validated high-performance liquid chromatography (HPLC) methods. Eighteen subjects completed the metoprolol study while 17 subjects completed the propranolol/hy...
Reflections on Fear: Montesquieu in Retrieval

According to most scholars, Montesquieu argues that fear threatens a loss of self. Disconnected from the exercise of reason, fear is an emotion that is supposed to prevent the individual from acting with any kind of moral or rational agency. Fear is also premised on the liquidation of civil society; intermediate institutions and plural social structures are destroyed so that despots can act with unmitigated power and violence. I argue that this view does not capture Montesquieu's theory. In my alternative account, fear is intimately connected to our capacity for reason and to our sense of self. It is built on a network of elites, the rule of law, moral education, and the traditional institutions of civil society. I conclude that twentieth-century social science remains too indebted to conventional interpretations of Montesquieu's views, and contemporary theorists would be better served by the alternative analysis proposed here.
Toxicity of synthetic pyrethroids to freshwater invertebrates

This report reviews the laboratory toxicity data on freshwater target and nontarget invertebrates exposed to pyrethroids and evaluates the state of the data. Early in their development, pyrethroids were shown to be highly effective insecticides against mosquitoes, blackflies and chironomids. Acute LC50 values for these target animals were often less than 1 μg/L. Acute exposures of nontarget invertebrates showed that some species were as sensitive as the target insects. Longer exposures, up to 28 d, showed that lethal effect concentrations were lowered with increased exposure duration. Unfortunately, the long—exposure tests were limited to a few species and a few pyrethroids, so no general commentary on no effect concentrations is possible. Some species were affected at concentrations near the analytical detection limit for pyrethroids. The data reviewed show that temperature, life cycle stage and exposure duration will be critical factors in developing the no effect concentrations that are important in risk assessments for nontarget invertebrates exposed to these insecticides.
Supersymmetric extension of the SU(3)×SU(2)×U(1) model

We describe a class of supersymmetric SU(3)×SU(2)×U(1) models where all quarks and leptons, as well as their scalar partners, get masses through one-loop radiative corrections.
Current management in polycythemia vera.

Abstract Myeloproliferative diseases (MPD) include polycythemia vera (PV), essential thrombocythemia, agnogenic myeloid metaplasia, and chronic myelogenous leukemia. The focus of this report is on PV, which is characterized by an increase in red blood cells, granulocytes, and platelets. Complications associated with PV are an increased risk of thrombosis and abnormal bleeding. Phlebotomy to a hematocrit less than 45% is the mainstay of treatment for erythrocythemia, but may further increase the platelet count, necessitating the use of a platelet-lowering agent in conjunction with phlebotomy. Other treatment strategies include low-dose aspirin or other antithrombotic therapy and cytoreduction. Mounting evidence of the leukemogenicity and mutagenicity of radioactive phosphorus and alkylating agents, as administered using “conventional” regimens, has restricted the liberal use of these treatments. Three drugs have emerged as useful because of their efficacy in reducing the elevated platelet count: anagrelide, hydroxyurea (HU), and interferon alfa (IFN). It is clear that no single agent satisfies all the needs for cytoreduction that arise during the course of PV. Future protocols should be designed that draw on the large body of experience already gained with these drugs to transcend the limitations of single-agent therapy and to improve quality of life as well as survival.
A novel TCR transgenic model reveals that negative selection involves an immediate, Bim-dependent pathway and a delayed, Bim-independent pathway.

A complete understanding of negative selection has been elusive due to the rapid apoptosis and clearance of thymocytes in vivo. We report a TCR transgenic model in which expression of the TCR during differentiation occurs only after V(D)J-like recombination. TCR expression from this transgene closely mimics expression of the endogenous TCRα locus allowing for development that is similar to wild type thymocytes. This model allowed us to characterize the phenotypic changes that occurred after TCR-mediated signaling in self-reactive thymocytes prior to their deletion in a highly physiological setting. Self-reactive thymocytes were identified as being immature, activated and CD4loCD8lo. These cells had upregulated markers of negative selection and were apoptotic. Elimination of Bim reduced the apoptosis of self-reactive thymocytes, but it did not rescue their differentiation and the cells remained at the immature CD4loCD8lo stage of development. These cells upregulate Nur77 and do not contribute to the peripheral T cell repertoire in vivo. Remarkably, development past the CD4loCD8lo stage was possible once the cells were removed from the negatively selecting thymic environment. In vitro development of these cells occurred despite their maintenance of high intracellular levels of Nur77. Therefore, in vivo, negatively selected Bim-deficient thymocytes are eliminated after prolonged developmental arrest via a Bim-independent pathway that is dependent on the thymic microenvironment. These data newly reveal a layering of immediate, Bim-dependent, and delayed Bim-independent pathways that both contribute to elimination of self-reactive thymocytes in vivo.
Use of data-driven phase space models in assessing the strength of a bolted connection in a composite beam

This work explores the role of empirical dynamical models in deducing the level of preload loss in a bolted connection. Specifically, we examine the functional relationship between data gleaned from locations on either side of the connection using nonlinear predictive models. This relationship, as quantified by a measure of prediction error, changes as a function of bolt loosening, thus allowing both the presence and magnitude of the axial load to be identified. The models are based on a phase space portrayal of the system dynamics and require only that the structure's response be low dimensional. The technique is demonstrated experimentally on a composite beam fastened to steel plates with four instrumented bolts. Results are compared to a similar approach using an auto-regressive (AR) modeling technique.
The mechanism of Q-enzyme action and its influence on the structure of amylopectin.

Abstract Q-Enzyme is responsible for the synthesis of the 1,6-branch linkages in amylopectin. Its action on a model amylodextrin containing a single branch linkage has been studied. It is concluded that the enzymic process whereby the branch linkages of amylopectin are synthesized is a random action of the branching enzyme on a complex—possibly a double helix—formed between two 1,4-α-glucan chains. This action pattern predicts a novel arrangement of the units chains in amylopectin.
Blood perfusion and transcutaneous oxygen level characterizations in human skin with changes in normal and shear loads — Implications for pressure ulcer formation

Abstract Background Decubitus ulcers (pressure ulcers) are localized areas of tissue breakdown in the skin and the underlying regions. Decubitus ulcers affect approximately 3 million people in the USA every year, including seniors, individuals with diabetes, and those who spend long periods in wheelchairs. Experimental studies demonstrate that static or dynamic normal loads cause blood occlusion in the skin, while prolonged loading conditions can result in skin damage. However, few studies report the effects of ‘normal and shear’ combined loading on blood perfusion. The goal of this research was to study alterations of transcutaneous oxygen levels and blood perfusion in human skin when both normal and shear loads were applied. Methods Fifteen human subjects were evaluated under seven different conditions for changes in transcutaneous oxygen and blood perfusion levels during applications of normal and shear loading on the forearm. Transcutaneous oxygen levels and blood perfusion were continuously measured using a Laser Doppler system, while applied forces were quantified with a multi-axis load cell. Findings Transcutaneous oxygen and blood perfusion levels decreased when shear loads were applied in addition to normal loads. Further, blood perfusion during recovery periods increased gradually from the first to the last test condition. Interpretation Results indicate that adding shear loads decreased transcutaneous oxygen and blood perfusion levels in the skin. Based on these findings, shear force may play a role in skin damage, and both shear and normal loads should be considered when trying to prevent ulcer development.
Environmental fate and distribution of technetium-99 in a deciduous forest ecosystem

Abstract The aims of the present research are to describe the uptake of 99 Tc by trees intercepting contaminated groundwater from a radioactive waste storage site, to identify the major 99 Tc pools within the woodland ecosystem and to assess the relative mobility of 99 Tc in the existing element cycle. Technetium in the groundwater freely passed through a dialysis membrane with a molecular weight exclusion limit of approximately 3500 amu and 99 Tc in the groundwater chromatographed on Biogel P-2 in a manner similar to pertechnetate anion (TcO 4 − ). Reducing conditions and organic associations at the study site were probably responsible for the relatively large amount (83–92%) of the 99 Tc that was nonextractable from soil by 0·01 m CaCl 2 . More than one-third of the 99 Tc was released from the soil by oxidizing reagents, indicating the presence of chemically reduced forms. The highest average 99 Tc concentrations in vegetation were found in herbaceous plants (18 530 pCi g −1 dry wt). Although 99 Tc was progressively accumulated over the growing season in tree leaves, average concentrations in tree wood and twigs were equal to or greater than concentrations in leaves. Tree wood was the major above-ground pool for 99 Tc because of the high concentrations in wood as well as the large amount of wood relative to other biomass at the site. Technetium was not easily leached from the trees by rainfall and was not readily extractable from forest floor leaf litter by water. The relative importance of return pathways for 99 Tc to the forest floor was leaf fall>stemflow >throughfall, indicating that 99 Tc was conserved by the trees. Snails and millipedes from the leaf litter layer concentrated technetium 20- and 16-fold, respectively, above levels found in the soil. Pertechnetate was rendered less bioavailable after ingestion by a leaf litter macroinvertebrate ( Porcellio sp.) common to the study site.
Heinrich Hertz and Philipp Lenard: Two Distinguished Physicists, Two Disparate Men

Heinrich Hertz (1857–1894) and Philipp Lenard (1862–1947) both had distinguished careers as physicists. They were together in Bonn from April 1891 to January 1894, Hertz as Director of the Bonn Physics Institute, and Lenard as his assistant. Each did important experimental work on cathode rays and the photoelectric effect, and in 1905 Lenard received the Nobel Prize for his work in these fields. Lenard had great respect and admiration for Hertz before going to Bonn and while there, but gradually allowed his esteem for his mentor (who died in 1894) to diminish as Lenard became increasingly anti-Semitic and involved in National Socialism and the Nazi movement. This article illustrates how differences in their characters and personalities, together with the tragic events of the Great War and its aftermath, resulted in Hertz deservedly being much more highly regarded today both as a physicist and as a man than is Lenard.
Reaction mechanisms for the coatings formed during the hot dipping of iron in 0 to 10 Pct Al-Zn baths at 450° to 700°C

The reaction mechanisms and the structures of the phases formed during the hot dipping of iron in 0 to 10 pct Al-Zn alloy baths at temperatures of 450° to 700°C were studied by X-ray diffraction and electron microprobe analysis techniques. A new mechanism for the inhibition reaction between iron and zinc is proposed. At bath temperatures below 600°C, a thin layer of an Fe-Al-Zn ternary compound forms on the iron surface and inhibits the growth of Fe-Zn phases. Breakdown of inhibition occurs during the dipping process when the ternary compound becomes rich in aluminum and transforms to a more stable structure which is isomorphous with Fe2Al5. While this breakdown is occurring, the zinc atoms react with iron and form the conventional Fe-Zn phases.
The Daily Maturation of Infant Behavior: A Cinema Study of Postures, Movements, and Laterality

(1942). The Daily Maturation of Infant Behavior: A Cinema Study of Postures, Movements, and Laterality. The Pedagogical Seminary and Journal of Genetic Psychology: Vol. 61, No. 1, pp. 3-32.
EUV defect characterization study on post litho and etch for 1x and 2x node processes

EUV mask metrology and inspection challenges as well as EUV patterned wafer metrology and inspection strategies must be addressed to enable EUV patterning for pilot and high volume production. In this work we present a defectivity analysis of defects from post EUV lithography and etch and the correlation between them on 40nm and 28nm half pitch (HP) line/space structures. The objective of the work was to study the lithography and etch process window vs. pitch as well as to characterize the performance of a DUV brightfield wafer inspection system on EUV stacks in order to detect EUV related DOI's. In addition to defect characterization for the lithography and etch layers, we present the results of scattering simulation from these layers, with polarized 266nm DUV illumination, to provide insight on the light-pattern interaction and on the critical detection parameters.
The young's moduli of glassy PdSiH alloys

Abstract The Young's moduli, E, of hydrogenated Pd 100−x Si x metallic glasses with 14⩽×⩽22 have been measured as a function of hydrogen content at room temperature and at hydrogen pressures up to 100 torr. For small hydrogen concentrations, n H , E is almost constant up to a limiting concentration, n H,c which depends on the alloy composition, x Si . Above n H,c , all hydrogenated PdSi glasses show a linear decrease in E with increasing n H . The elasticity data as well as previously reported solubility data are analyzed according to a two-site model based on a dense random packing of hard spheres (DRPHS) structure.
Hydrogen exchange of rhenium(VII) heptahydridobis(triphenylphosphine) with water, aniline, methanol, and itself

Abstract The hydride ligands of ReH7(PPh3)2 undergo fast hydrogen exchange with water at room temperature while exchanging with the hydrogen atoms of aromatic solvent molecules at a slower rate. The amount of time required for isotopomer peaks to appear in the 1H NMR hydride resonance of ReH7(PPh3)2 was used to distinguish fast hydrogen exchange from slow hydrogen exchange. The room temperature 1H NMR T1 values of adventitious water resonances were used to distinguish two rhenium heptahydride compounds that participate in fast hydrogen exchange with water, ReH7(PPh3)2 and ReH7(AsPh3)2, from one compound that does not participate, ReH7(PCy3)2. Fast hydrogen exchange between ReH7(PPh3)2 and water is greatly slowed or stopped when the compound is dissolved in a solution that contains DMSO. The compound ReH6D(PPh3)2, an isotopomer of ReH7(PPh3)2 that was prepared in situ, exhibited an isotopomer shift in its 31P–{1H} NMR spectrum as well as D–P coupling when measured in the solvent anisole. In a solvent system containing deuteroaniline, nearly all of the hydride ligands were exchanged with deuterium, from aniline, in less than 2 h. Hydrogen exchange between the hydride ligands of ReH7(PPh3)2 and deuteroaniline was found to be reversible upon the addition of normal aniline. The distribution of hydrogen isotopes in the rhenium coordination spheres reflected the overall composition of the exchangeable hydrogen isotopes present in the bulk sample. In a deuteromethanol-containing solvent system, the exchange of hydride ligands between separate ReH7(PPh3)2 isotopomers was evident. The presumed hydrogen exchange intermediate, [ReH6(H2)(PPh3)2]+, may be responsible for the evident exchange of hydride ligands and may also be important to the thermal loss of dihydrogen from ReH7(PPh3)2.
Somatosensory potentials, CSF creatine kinase BB activity, and awakening after cardiac arrest.

Objective: To examine the utility of somatosensory evoked potential (SEP) peaks and CSF creatine kinase BB isoenzyme activity (CKBB) in predicting nonawakening from coma due to cardiac arrest. Background: Accurate predictors of neurologic outcome in patients comatose after cardiac arrest are needed to improve medical decision making. Methods: A total of 72 comatose patients had bilateral median SEPs, and of these, 52 had CSF and CKBB. Awakening was defined as following commands or having comprehensible speech. Both short (N1) and long (N3) latency SEP peaks were analyzed. Nonparametric analyses were used. Results: For patients who had both tests, CKBB ≥ 205 U/L predicted nonawakening with a sensitivity of 49% and a specificity of 100%. Bilateral absence of the N1 peak predicted nonawakening with a sensitivity of 53% and a specificity of 100%. Using CKBB ≥ 205 U/L, bilaterally absent SEP N1 peaks, or both predicted nonawakening with a sensitivity of 69% and a specificity of 100%. Using CKBB ≥ 205 U/L, bilaterally absent N1 peaks, bilateral N3 ≥ 176 msec or absent, or some combination predicted nonawakening with a sensitivity of 78% and a specificity of 100%. Conclusion: The combination of an absent N1 peak and elevated CKBB performs better than either alone in predicting nonawakening after cardiac arrest. Prolonged or absent N3 latency may increase sensitivity. These results should be interpreted with caution given the small number of patients and the possibility of a self-fulfilling prophecy.
Diurnal periodicity in airborne fungi in an orchard

Abstract Four Kramer-Collins spore samplers were operated continously in a small apple orchard, from July 26 to 30, 1965. Numbers of the common spore types, hyphal fragments, and pollen were determined per cubic foot. Rains occurred on July 27 and 28. The precipitation removed Cladosporium and Alternaria from the air, caused spores of puffballs to be dispersed immediately, and stimulated the discharge of ascospores and basidiospores. Following the rains, conditions were favorable for sporulation and a diurnal pattern became evident. Cladosporium, Alternaria, Cercospora, Helminthosporium and hyphal fragments had daytime peaks, while ascospores of Sordaria and Hypoxylon and basidiospores of Coprinus and Sporobolomyces had distinct night-time peaks. Pollen grains of Acalypha ostryaefolia had peaks between 6 and 7 a.m. on 4 successive days following the rain.
Human Rights in Korea: Historical and Policy Perspectives . Edited by William Shaw. Cambridge: Harvard University Press, 1991.

These chapters by eight Korea specialists present a new approach to human rights issues in Korea. Instead of using an external and purely contemporary standard, the authors work from within Korean history, treating the successive phases of Korea's modern century to examine the uneasy fate of human rights and some of the ideas of human rights as they have developed in the Korean context. Beginning with the Independence Club of the late nineteenth century and continuing through to the constitutional and judicial structures underlying the Sixth Republic Government of Roh Tae Woo in South Korea, these papers illuminate the sometimes complex interactions between modern Korean human-rights issues and the legacies of Korean culture and colonial occupation. The contributors provide a corrective to two common errors: one, an overemphasis on the tension between residual Confucian culture and human-rights concepts; two, the opposite error, a defensive nationalism that gives rise to ill-founded efforts to identify democratic antecedents in the Korean past. Instead, these authors allow each episode in the emergence of Korean human rights thought and action to stand in the context of its own time and of Korea's modern history. The final sections deal with the usefulness and appropriateness of U.S. policies toward human rights in South Korea and comparatively with the overall issues raised in the volume.
Signature of a Pairing Transition in the Heat Capacity of Finite Nuclei

The heat capacity of iron isotopes is calculated within the interacting shell model using the complete $({pf+0g}_{9/2})$ shell. We identify a signature of the pairing transition in the heat capacity that is correlated with the suppression of the number of spin-zero neutron pairs as the temperature increases. Our results are obtained by a novel method that significantly reduces the statistical errors in the heat capacity calculated by the shell model Monte Carlo approach. The Monte Carlo results are compared with finite-temperature Fermi gas and BCS calculations.
Variation in Quantitative Respirator Fit Factors Due to Fluctuations in Leak Size During Fit Testing

Variation in fit factors during quantitative respirator fit testing was studied for a high degree of fit (aerosol fit factors>1000) and a low degree of fit (aerosol fit factors<1000). In a controlled human study, fit factors were determined sequentially for three different exercises by (1) an aerosol fit test (using a portable condensation nuclei counter and room aerosol as the test agent) and (2) the newly developed dichotomous-flow fit test (Dichot). For the higher level of respirator fit, the aerosol fit factors were 30 to 60 times the corresponding flow fit factors, and for the lower level of respirator fit they were 2 to 4 times the flow fit factors. A coefficient of variation (CV) of 84% (GSD 1.6) for the higher respirator fit and 178% (GSD 2.2) for the lower respirator fit data was observed in the human study when aerosol fit factors for the three exercises were pooled. In a similar mannequin study, the center sampling probe gave aerosol fit factors with a CV of 5.4% (GSD 1.05). The flow fit factor...
When Visions of the Rainbow Nation Are Not Enough: Effect of Post-Apartheid Higher Education Reform on Social Cohesion in South Africa

Under the apartheid state, higher education was structured to maintain and reproduce the subordinate social and economic position of non-Whites. The post-apartheid higher education sector suffered from fragmentation along racial lines, a lack of sustainability, and a structural incapacity to meet the challenges of restructuring and development. After more than a decade of reform, the Ministry of Education announced the plan to restructure the higher education system, consolidating 36 institutions into 21. Institutional mergers were perhaps the most significant structural change to the higher education system since post-apartheid desegregation of universities. This article examines the role of these new higher education institutions in promoting social cohesion within the university and by extension, the society at large. The institutional functions of the new universities are evaluated on the basis of the following indicators: (a) curriculum, (b) institutional climate, (c) perception of fair treatment of ...
Variational analysis of diffusion in a catalyst pore

Abstract Diffusion processes in a catalyst pore can be analyzed by variational methods to establish a system of natural finite difference equations. Solution of these equations provides the cencentration profiles of the reactant in the pore for arbitrary stoichiometry. The method provides a convenient way of constructing catalyst efficiency curves for complex kinetic expressions.
Bacterial translocation to mesenteric lymph nodes is increased in cirrhotic rats with ascites

Abstract Background/Aims: Cirrhotic patients are predisposed to develop spontaneous bacteremias and/or peritonitis, mainly caused by enteric bacteria. The aim of this study was to investigate if bacterial translocation, which is the passage of bacteria from the intestinal lumen to regional lymph nodes and/or the systemic circulation, is increased in a rat model of cirrhosis. Methods: Rats were studied after 12–16 weeks of CCl 4 inhalation, when samples of mesenteric lymph nodes, blood, liver, and spleen for standard bacteriologic cultures and a fragment of colon and liver for histology were obtained. Immunostaining of the cecum was performed using a polyclonal anti- Escherichia coli antibody. Results: A significantly greater proportion of rats with cirrhosis and ascites (5 of 9; 56%) had positive mesenteric lymph node cultures compared with cirrhotics without ascites (0 of 9) and normal controls (0 of 12) ( P E. coli was isolated from both mesenteric lymph nodes and ascites. Rats with cirrhosis and ascites had significantly greater cecal submucosal edema and inflammation than rats with no ascites and controls. Immunoreactivity with E. coli was present in the cecal wall in 3 of 5 animals with E. coli translocation to mesenteric lymph nodes. Conclusions: In cirrhotic rats, bacterial translocation is increased after the development of ascites and may be a major factor in the development of spontaneous infections in cirrhosis.
The effect of time-varying mortality and carbon assimilation on models of carbon allocation in annual plants

Models of optimal carbon allocation schedules have influenced the way plant ecologists think about life history evolution, particularly for annual plants. The present study asks (1) how, within the framework of these models, are their predictions affected by within-season variation in mortality and carbon assimilation rates?; and (2) what are the consequences of these prediction changes for empirical tests of the models? A companion paper examines the basic assumptions of the models themselves. I conducted a series of numerical experiments with a simple carbon allocation model. Results suggest that both qualitative and quantitative predictions can sometimes be sensitive to parameter values for net assimilation rate and mortality: for some parameter values, both the time and size at onset of reproduction, as well as the number of reproductive intervals, vary considerably as a result of small variations in these parameters. For other parameter values, small variations in the parameters result in only small changes in predicted phenotype, but these have very large fitness consequences. Satisfactory empirical tests are thus likely to require much accuracy in parameter estimates. The effort required for parameter estimation imposes a practical constraint on empirical tests, making large multipopulation comparisons impractical. It may be most practical to compare the predicted and observed fitness consequences of variation in the timing of onset of reproduction.
A Novel Solution Processable Electron Acceptor, C 60 (CN) 2 , for Bulk Heterojunction Photovoltaic Applications

Photovoltaic devices based on soluble conjugated polymers have gained great interest in recent years because of the potential low cost of production and ease of fabrication. PCBM ([6,6]-phenyl-C 61 -butyric acid methyl ester), a fullerene derivative, has been extensively investigated as a solution processable electron acceptor for bulk-heterojunction (BHJ) photovoltaic devices blended with conjugate polymers like P3HT [poly(3-hexylthiophene)]. Here, we investigated a novel solution processable organic semiconductor, C 60 (CN) 2 , as an electron acceptor for bulk heterojunction photovoltaic applications. Optical and electrical properties of C 60 (CN) 2 are studied and compared with PCBM. Blend devices with P3HT and C 60 (CN) 2 have been fabricated and compared with P3HT-PCBM devices. The effect of thermal annealing on the device performance is evaluated. Open circuit voltage, short circuit current, fill factor and total efficiency data are compared with PCBM based devices.
A non-parametric approach to smoothing by aggregation over preferences

Abstract A distributional dispersion condition on C2 monotone preferences, defined by unit normals to indifference surfaces, yields a C0 mean demand function when one integrates over such suitably diffuse consumers with convex preferences, regardless of the distribution of their initial endowments. For non-convex preferences, the dispersion condition implies that at any price vector, individual demands are finite sets for almost every agent. A stronger dispersion condition, involving both utility functions and unit normals, yields C0 mean demand functions with monotone non-convex preferences.
Pre- and Postsynaptic Role of Dopamine D2 Receptor DD2R in Drosophila Olfactory Associative Learning

Dopaminergic neurons in Drosophila play critical roles in diverse brain functions such as motor control, arousal, learning, and memory. Using genetic and behavioral approaches, it has been firmly established that proper dopamine signaling is required for olfactory classical conditioning (e.g., aversive and appetitive learning). Dopamine mediates its functions through interaction with its receptors. There are two different types of dopamine receptors in Drosophila: D1-like (dDA1, DAMB) and D2-like receptors (DD2R). Currently, no study has attempted to characterize the role of DD2R in Drosophila learning and memory. Using a DD2R-RNAi transgenic line, we have examined the role of DD2R, expressed in dopamine neurons (i.e., the presynaptic DD2R autoreceptor), in larval olfactory learning. The function of postsynaptic DD2R expressed in mushroom body (MB) was also studied as MB is the center for Drosophila learning, with a function analogous to that of the mammalian hippocampus. Our results showed that suppression of presynaptic DD2R autoreceptors impairs both appetitive and aversive learning. Similarly, postsynaptic DD2R in MB neurons appears to be involved in both appetitive and aversive learning. The data confirm, for the first time, that DD2R plays an important role in Drosophila olfactory learning.
Hyperfine studies of dangling bonds in amorphous silicon.

Dangling-bond electron-spin hyperfine spectra have been measured in $^{29}\mathrm{dilute}$ and $^{29}\mathrm{enriched}$ a-Si:H. From the data we deduce that the electron wave function is largely p-like and has 50--80 % of its density on the central atom with the remainder predominantly on at least one of the back-bonded neighbors. A significant degree of weak back bonding for most dangling-bond sites is invoked to explain the large hyperfine coupling to a back-atom nucleus. Hydrogen back bonding at the dangling-bond site is shown to be negligible.
IO: Could SO2 condensation/sublimation cause the sometimes reported post‐eclipse brightening?

It is shown that each of the three quantifiable brightening characteristics (i.e., amplitude, time-scale /half-life/, and temporal variability) suggests that brightening of Io may be due to condensation and sublimation of SO2 frost. This is concentrated within a region that encompasses both the subsolar points at the time of entrance into and emergence from eclipse, and volcanic sources. Qualitatively and intuitively, an SO2 frost hypothesis is found to provide good possibilities for explaining any variations in Io's ability to brighten, which may occur on a time scale of years.
Effect of oxygen concentration on transverse water proton relaxation times in erythrocytes homozygous and heterozygous for hemoglobin S

Abstract The transverse water proton relaxation times (T2) of erythrocytes homozygous and heterozygous for hemoglobin S have been measured as a function of oxyhemoglobin concentration at 37 °C. An immediate decrease in T2 is observed in S/S erythrocytes as the amount of oxyhemoglobin is decreased and the maximum change is observed at 50% deoxyhemoglobin S. In heterozygous erythrocytes, the T2 remains unchanged until a critical level of deoxyhemoglobin is attained. The critical level of deoxyhemoglobin is a function of the percentage of hemoglobin S in the heterozygous erythrocytes. A Hill plot of the data obtained from S/S erythrocytes gives an n value of around 2.4. These results suggest that the measurement of T2 is sensitive to the very early stages of the polymerization process. This suggestion is supported by calculations; our T2 measurements are sensitive to a range of correlation times expected for hemoglobin monomers at one extreme and linear polymers of seven hemoglobin molecules at the other extreme.
Cloning the Drosophila homolog of the xeroderma pigmentosum complementation group C gene reveals homology between the predicted human and Drosophila polypeptides and that encoded by the yeast RAD4 gene

A human xeroderma pigmentosum group C (XPC) cDNA has been previously isolated by functional complementation (Legerski and Peterson, Nature, 359, 70-73, 1992). Sequence analysis did not reveal protein motifs which might suggest a possible biochemical function for the putative XPC protein. In order to identify functional domains in the translated XPC sequence the homologous gene from Drosophila melanogaster, designated XPCDM, was cloned by DNA hybridization. Sequence analysis of an apparently full-length cDNA revealed an open reading frame which can encode a predicted polypeptide of 1293 amino acids. Significant homology of the C-terminal 346 amino acids with both the human XPC and Saccharomyces cerevisiae Rad4 protein sequences is observed, suggesting that these proteins are functional homologs.