cssi/SciSciGPT-SciSciNet huggingface dataset:
A New Adaptive Method for Geometric Convergence

Conventional wisdom in solving transport problems is to identify unbiased, low variance (or low variation) estimators to estimate unknown functionals of the solution by Monte Carlo (or quasi-Monte Carlo) algorithms. Our adaptive implementations using this approach have involved the iterative improvement of either an approximate solution obtained through correlated sampling (SCS) or of an approximate importance function (AIS) for the problem. Each of these methods has some drawbacks: for SCS, the (required) estimation of the residual creates various problems and for AIS, sampling from the complex expressions that result from the use of an importance function can be extremely costly. In both of these cases, substantial loss of precision may result. A new adaptive method — generalized weighted analog sampling (GWAS) - combines many of the best features of SCS (simple sampling functions) and AIS (rapid error reduction) and makes use of biased (but asymptotically unbiased) estimators in a very flexible and efficient algorithm. In this work we sketch the needed theory and present numerical results that confirm the potential of the new method, at least for some model transport problems.
Connections between the Dry Bulk Freight Index and the Cyclical Economic Activity of the G7 Countries

The article analyses the connections between the dry bulk freight market and the economic activity of certain countries. The objective was to confirm the existence of a similar cyclical nature for the Baltic Dry Index and main indicators of the business cycle of the G7 countries. The applied macroeconomic variables were: the real GDP and the industrial production index. In examination a spectral analysis was used. The discovered identical periodicities were analyzed in terms of time relations. It was demonstrated, that the cyclical part of the BDI (periodicity of 13.1 and 15.3 quarters) either leads or is coincident with the indicators of the business cycle. The global financial crisis in 2008-2009 showed that the behaviour of freight indices was similar to stock exchange indices and macroeconomic variables in advanced economies. It is worth to observe shipping market because higher values of freight indices could anticipate increasing demand for sea trade and economic growth
Specification and Forecasting of Outages on Satellite Communication and Navigation Systems

The ionized upper atmosphere often develops electron density irregularities which cause amplitude and phase scintillations of satellite signals. Scintillations, when intense, can cause outages in satellite communication systems and in Global Positioning System (GPS) for navigation. The performance of these systems can be improved by providing global specification and forecast of scintillation. A scintillation specification system, Scintillation Network Decision Aid (SCINDA), has been developed for the South American sector. An equatorial satellite, Communication Navigation Outage Forecasting System (C/NOFS), equipped with suitable sensors, has been planned for the specification and forecast of equatorial scintillation.
The Isolation and Mode of Action of a Bacterial Glucanosyltranferase

A glucanosyltransferase has been obtained in a high state of purity from a bacterium of the Bacillus group. The enzyme is distinct from the other carbohydrases produced by the organism. The pH optimum for the transferase is 5, and the molecular weight is in the range of 70,000 to 80,000. The transferase is stable at low temperatures but is rapidly inactivated at elevated temperatures. The new enzyme effects a transfer of glucanosyl segments from maltopentaose, higher molecular weight maltohomologues or starch to maltopentaose, and other maltohomologues to yield new oligosaccharides. The transferase may be of importance in the metabolism of starch in the bacterium.
The importance of interaction for academic success in online courses with hearing, deaf, and hard-of-hearing students

This paper reports the findings of three studies within a program of research designed to better understand the factors contributing to the academic achievement of students in online courses and the contributions of interaction to online learning. The first study compared the academic achievement of students in the online and face-to-face (F2F) sections of multiple courses. In the second study, an online survey was used to obtain student perceptions of course satisfaction, learning, and communication. These factors were then related, using binary logistic regression analysis, to the amount of interaction that occurred in the students’ respective online courses; information from the myCourses course management system was used to quantify the amount of interaction that occurred in online courses. In the final study, both datasets were used to examine the academic achievement of students in online courses based upon the amount of interaction that had actually occurred. Whenever possible, a subgroup of deaf and hard-of-hearing students was included in the study to increase our understanding of the role that communication plays in the teaching-learning process. Our findings indicate that students enrolled in online courses, especially those designed with high levels of online interaction, receive higher grades and report greater learning than students in comparable F2F courses. In addition, online courses appear to provide deaf and hard-of-hearing students with special benefits in terms of academic achievement through online discussion. Overall, the studies illuminate how the quantity of interaction in online discussions relates to important success factors. Students in online courses with more interaction outperformed students in online courses with less interaction.
Front-flash thermal imaging characterization of continuous fiber ceramic composites.

Infrared thermal imaging has become increasingly popular as a nondestructive evaluation method for characterizing materials and detecting defects. One technique, which was utilized in this study, is front-flash thermal imaging. We have developed a thermal imaging system that uses this technique to characterize advanced material systems, including continuous fiber ceramic composite (CFCC) components. In a front-flash test, pulsed heat energy is applied to the surface of a sample, and decay of the surface temperature is then measured by the thermal imaging system. CFCC samples with drilled flat-bottom holes at the back surface (to serve as ''flaws'') were examined. The surface-temperature/time relationship was analyzed to determine the depths of the flaws from the front surface of the CFCC material. Experimental results on carbon/carbon and CFCC samples are presented and discussed.
Formation of Auroral Arcs by Plasma Sheet Processes

It is noted that, in the distant plasma sheet, it is likely that curvature drift is the most important source of drift parallel to the electric field, leading to what is commonly called Fermi acceleration of the particles. The energization mechanism here is proportional to the neutral sheet current density. It is a form of field-aligned acceleration, with rapid lowering of mirror points, caused by the transverse electric field in the plasma sheet. It is noted that the process will work for both negative and positive particles. A filamentation of the neutral current sheet is postulated. Here, the maximum energization by curvature drift and the accompanying intense precipitation will form an auroral band or arc along the sheet of magnetic field lines that maps out to the local enhancement of the crosstail current, explaining inverted V events.
Population inversion in step quantum wells at 10 /spl mu/m wavelength

In this work, it is shown that population inversion can be achieved between subbands in a step quantum well with a high width ratio based on carrier capture processes. It is known that in quantum well structures, emission of LO phonons is the main carrier capture mechanism. The LO-phonon scattering rate depends on the Froelich matrix element and the overlap of the initial and final wave functions squared. In a step quantum well with a high ratio of the step width to the well width the wave function overlap of the state in the step and the state in the well is reduced and thus a longer capture time results. If the carriers of the state in the well can be removed by an adjacent quantum well by tunneling, population inversion can be realized.
Metal–Halogen Secondary Bonding in a 2,5-Dichlorohydroquinonate Cobalt(II) Complex: Insight into Substrate Coordination in the Chlorohydroquinone Dioxygenase PcpA

Despite the unprecedented selectivity of the hydroquinone ring-cleaving dioxygenase PcpA for ortho-chlorohydroquinones, there are no examples of an ortho-chlorohydroquinone bound to a transition-metal complex. Herein, the synthesis and characterization of (TpPh2Co)2(μ-2,5-dichlorohydroquinonate), for which TpPh2 is tris(3,5-diphenylpyrazolyl)borate, were explored. The dianionic 2,5-dichlorohydroquinonate bridges two (TpPh2Co) moieties and coordinates each cobalt(II) center through the oxygen and chlorine atoms of the chlorohydroquinone. The Co–Cl distance of 2.778 A shows the characteristics of a metal–halogen secondary bond, as we previously showed in ortho-halophenolate complexes. This compound represents the first example of metal–halogen secondary bonding with a halohydroquinone and, thus, provides a potential structural model for selective substrate binding to the metal center in PcpA.
An Image Coding and Reconstruction Scheme for Mobile Computing

An asynchronous transfer mode (ATM) wireless network has bursty and high error rates. To combat the contiguous bit loss due to damaged or dropped packets, this paper presents a code packetization and image reconstruction scheme. The packetization method distributes the loss in both frequency and spatial domains to reduce the chance that adjacent DCT blocks lose the same frequency components. The image reconstruction takes into consideration the spatial characteristics represented by the frequency components. Combining these two approaches one can reconstruct the damaged images more accurately, even under very high loss rates. In addition, since the reconstruction technique is computational efficient, it conserves system resources and power consumption, which are restrictive in mobile computers.
Geochemistry of an ultramafic-rodingite rock association in the Paleoproterozoic Dixcove greenstone belt, southwestern Ghana

Abstract Rodingite occurs in ultramafic rocks within the Paleoproterozoic (Birimian) Dixcove greenstone belt in southwestern Ghana. U–Pb analyses of zircons from granitoids intrusive into the greenstone belt constrain the age of the rodingite-ultramafic association to be older than 2159 Ma. The ultramafic complex consists of variably serpentinized dunite and harzburgite overlain by gabbroic rocks, which together show petrographic and geochemical characteristics consistent with their formation by fractional crystallization involving olivine and plagioclase cumulates. Major and trace element concentrations and patterns in the ultramafic–mafic cumulate rocks and associated plagiogranite are similar to rocks in ophiolitic suites. The rodingites, which occur as irregular pods and lenses, and as veins and blocks in the serpentinized zones, are characterized by high Al2O3 and CaO contents, which together with petrographic evidence indicate their formation from plagioclase-rich protoliths. The peridotites are highly depleted in REE and display flat, chondrite-normalized REE patterns with variable, but mostly small, positive Eu anomalies whereas the rodingites, which are also highly depleted, with overall REE contents from 0.04 to 1.2 times chondrite values, display distinct large positive Eu anomalies. It is proposed that the rodingite-bearing Birimian ultramafic complex and associated pillowed greenstone belt basalts may represent fragments of a Paleoproterozoic oceanic lithosphere.
A Novel Ca2+ Entry Mechanism Is Turned On during Growth Arrest Induced by Ca2+ Pool Depletion

Ca2+ pool depletion with Ca2+ pump blockers induces growth arrest of rapidly dividing DDT1MF-2 smooth muscle cells and causes cells to enter a stable, quiescent G0-like growth state (Short, A.D., Bian, J., Ghosh, T.K., Waldron, R.T., Rybak, S.L., and Gill, D.L. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 4986-4990). Here we reveal that induction of this quiescent growth state with the Ca2+ pump blocker, thapsigargin, is correlated with the appearance of a novel caffeine-activated Ca2+ influx mechanism. Ca2+ influx through this mechanism is clearly distinct from and additive with Ca2+ entry through store-operated channels (SOCs). Whereas SOC-mediated entry is activated seconds after Ca2+ pool release, caffeine-sensitive influx requires at least 30 min of pool emptying. Although activated in the 1-10 mM caffeine range, this mechanism has clearly distinct methylxanthine specificity from ryanodine receptors and is not modified by ryanodine. It is also unaffected by the Ca2+ channel blockers SKF96365 or verapamil and is independent of modifiers of cyclic nucleotide levels. Growth arrest by thapsigargin-induced Ca2+ pool depletion can be reversed by treatment with 20% serum (Waldron, R.T., Short, A.D., Meadows, J.J., Ghosh, T.K., and Gill, D.L. (1994) J. Biol. Chem. 269, 11927-11933). The serum-induced return of functional Ca2+ pools and reentry of cells into the cell cycle correlates exactly with the disappearance of the caffeine-sensitive Ca2+ influx mechanism. Therefore, appearance and function of this novel Ca2+ entry mechanism are closely tied to Ca2+ pool function and cell growth state and may provide an important means for modifying exit from or entry into the cell cycle.
Microvascular anastomosis training model based on a Turkey neck with perfused arteries.

Objective The microvascular anastomosis (MA) technique remains an important aspect of modern neurosurgical practice. Specialized training is essential for mastering the anastomosis of small vessels. To minimize animal use and to create a simple but realistic training model, we developed a pulsatile perfused arteries model based on turkey carotid arteries for microvascular anastomosis training. Methods Approximately 10-cm-long segments of turkey necks were used as a material to set up this model. The diameter of turkey carotid arteries at the neck level was found to be between 1 and 3 mm. Both carotid arteries on the neck segment were cannulated and incorporated into a closed circulation circuit consisting of silicone tubes and an infusion pump that provided continuous arterial-like flow and pulsation during the MA training. Tubing connection with both proximal and distal ends of the carotid arteries allowed circulatory patency during vessel clamping and anastomosis creation. Different fluids ranging from simple water to various colored solutions or even whole blood could be used for vascular perfusion in this experimental setup. Fluid output was maintained between 11 and 16 ml/min. Minimum pressure was set at 80 cm/H20, and maximum pressure was set at 160 cm/H20. Mean fluid flow through the arteries was 8 to 13 ml/min. End-to-end, end-to-side, and side-to-side MA may be performed on this model. Results This training model provides several advantages: the materials are easily obtainable and inexpensive, pulsatile flow through the arteries is realistic, the model is easy to manage, and there is no need for special facilities for animal care or anesthesia that are required for live animals. The diameter and structure of turkey carotid arteries are essentially identical to the human cortical vessels and distal branches of the superficial temporal artery. Conclusion The pulsatile perfused carotid arteries model presents a realistic MA training model. It provides an inexpensive and simple setup for educational purposes. This technique can minimize live animal and anesthesia needs for MA training. Wide use of this model may enhance and popularize MA training and education.
Uncertain value of urinary sediments in the diagnosis of amyloidosis.

IN their article on the appearance of amyloid fibrils in the urinary sediment of a patient with amyloidosis1 Derosena, Koss and Pirani emphasized its potential clinical, diagnostic and investigativ...
Tungsten Disulfide Nanotubes Reinforced Biodegradable Polymers for Bone Tissue Engineering

In this study, we have investigated the efficacy of inorganic nanotubes as reinforcing agents to improve the mechanical properties of poly(propylene fumarate) (PPF) composites as a function of nanomaterial loading concentration (0.01–0.2 wt.%). Tungsten disulfide nanotubes (WSNTs) were used as reinforcing agents in the experimental group. Single- and multi-walled carbon nanotubes (SWCNTs and MWCNTs) were used as positive controls, and crosslinked PPF composites were used as the baseline control. Mechanical testing (compression and three-point bending) shows a significant enhancement (up to 28–190%) in the mechanical properties (compressive modulus, compressive yield strength, flexural modulus and flexural yield strength) of WSNT-reinforced PPF nanocomposites compared to the baseline control. In comparison to the positive controls, significant improvements in the mechanical properties of WSNT nanocomposites were also observed at various concentrations. In general, the inorganic nanotubes (WSNTs) showed mechanical reinforcement better than (up to 127%) or equivalent to that of carbon nanotubes (SWCNTs and MWCNTs). Sol fraction analysis showed significant increases in the crosslinking density of PPF in the presence of WSNTs (0.01–0.2 wt.%). Transmission electron microscopy (TEM) analysis on thin sections of crosslinked nanocomposites showed the presence of WSNTs as individual nanotubes in the PPF matrix, whereas SWCNTs and MWCNTs existed as micron-sized aggregates. The trend in the surface area of nanostructures obtained by Brunauer–Emmett–Teller (BET) surface area analysis was SWCNTs > MWCNTs > WSNTs. The BET surface area analysis, TEM analysis and sol fraction analysis results taken together suggest that chemical composition (inorganic vs. carbon nanomaterials), the presence of functional groups (such as sulfide and oxysulfide) and individual dispersion of the nanomaterials in the polymer matrix (absence of aggregation of the reinforcing agent) are the key parameters affecting the mechanical properties of nanostructure-reinforced PPF composites and the reason for the observed increases in the mechanical properties compared to the baseline and positive controls.
Maximizing the Alzheimer's Disease Neuroimaging Initiative II

The Alzheimer's Disease Neuroimaging Initiative is the largest public-private partnership on brain research underway at the National Institutes of Health. This 6-year study tracks cognitive and brain changes in normal subjects, those with mild cognitive impairment, and individuals with Alzheimer's disease. It was designed to provide better tools for performing effective clinical trials, and is slated to run until 2010. While data are being generated and analyzed, researchers involved in the study are developing an extension, i.e., the Alzheimer's Disease Neuroimaging Initiative II. The Foundation for the National Institutes of Health and the Alzheimer's Association convened a meeting to review the progress, evaluate future directions, and obtain the United States Food and Drug Administration's perspective on how the Alzheimer's Disease Neuroimaging Initiative could affect the drug-approval process.
Elective intracranial arterial stenting

Abstract Traditionally, the subject of revascularization of cerebral arteries for stroke prevention has been limited to discussions of carotid endarterectomy (CEA). More recently, endovascular therapy, particularly stenting, has become the focus of intense investigation. Probably, there is no better potential application for endovascular stenting than in the treatment of lesions involving the intracranial portions of the cerebral arterial vasculature. Indeed atherosclerotic pathology of these vessels seems to be associated with a significantly high risk for stroke, even when medical therapy is maximized. In addition, the evolution of technology and experience of the interventionalists have resulted in improved outcomes and has underscored the potential of treating these patients using endovascular techniques. The present is a summary of the current techniques and experience in the elective treatment of intracranial lesions using endovascular stenting.
Host Range and Cytopathogenicity of the Highly Attenuated MVA Strain of Vaccinia Virus: Propagation and Generation of Recombinant Viruses in a Nonhuman Mammalian Cell Line

Abstract Modified vaccinia virus Ankara (MVA), attenuated by over 500 passages in primary chick embyro fibroblasts (CEF), is presently being used as a safe expression vector. We compared the host ranges of MVA and the parental Ankara strain in CEF and 15 permanent cell lines. The cells could be grouped into three categories: permissive, semipermissive, and nonpermissive. For MVA, the permissive category consisted of primary CEF, a quail cell line derived from QT6, and the Syrian hamster cell line BHK-21. Only in BHK-21 cells did the virus yield approach that occurring in primary CEF. The semipermissive category included two African green monkey cell lines: BS-C-1 and CV-1. The nonpermissive category for MVA consisted of three human cell lines HeLa, 293, and SW 839; one rhesus monkey cell line FRhK-4; two Chinese hamster cell lines CHO and CHL; one pig cell line PK(15); and three rabbit cell lines RK13, RAB-9, and SIRC. The grouping for MVA with a restored K1L host range gene was similar except for the inclusion of RK13 cells among permissive lines. The grouping for the Ankara strain, however, was quite different with more permissive and semipermissive cell lines. Nevertheless, in cells that were permissive for MVA, the virus replicated to higher levels than Ankara, consistent with both positive and negative growth elements associated with the adaptation of MVA. The cell lines were also characterized according to their susceptibilty to MVA-induced cytopathic effects, expression of a late promoter regulated reporter gene by an MVA recombinant, and stage at which virion morphogenesis was blocked. Finally, the permissive BHK-21 cell line was shown to be competent for constructing and propagating recombinant MVA, providing an alternative to primary CEF.
Spectral response of a plant canopy with different soil backgrounds

Abstract The spectral behavior of a cotton canopy with four soil types alternately inserted underneath was examined at various levels of vegetation density. Measured composite spectra, representing various mixtures of vegetation with different soil backgrounds, were compared with existing measures of greenness, including the NIR-red band ratios, the perpendicular vegetation index (PVI), and the greenness vegetation index (GVI). Observed spectral patterns involving constant vegetation amounts with different soil backgrounds could not be explained nor predicted by either the ratio or the orthogonal greenness measures. All greenness measures were found to be strongly dependent on soil brightness. Furthermore, soil-induced greenness changes became greater with increasing amounts of vegetation up to 60% green cover. The results presented suggests that soil and plant spectra interactively mix in a nonadditive, partly correlated manner to produce composite canopy spectra.
Lab Attendance and Academic Performance

The benefits from attendance of lectures have been established in the literature. This paper focuses on attendance not of the lecture, but of smaller labs. These labs are 50 minutes one-day-a-week sessions to emphasis material covered during lecture. Using a 200-student Principles of Economics class that covers microeconomics with six different labs, we investigate the effect of lab attendance on exam performance by taking into account individual characteristics. We find that lab attendance benefits the student in overall exam performance.
Social factors influencing immigration attitudes: an analysis of data from the General Social Survey

Abstract This report partly replicates and also extends previous work exploring social factors influencing public opinion concerning immigration policy in the United States. Our findings are that college education and perceived cultural threats, especially to the English language, have the most impact upon immigration views. Other variables having some effect are political ideology, economic outlook, age, and sex. Effects of race, income, and fear of crime appear to be negligible. The findings are discussed in light of a multifactor theory of immigration opinion.
An eastward propagating two‐day wave: Evidence for nonlinear planetary wave and tidal coupling in the mesosphere and lower thermosphere

[1] Temperature observations from the SABER instrument on the TIMED spacecraft are used to investigate the structure and evolution of an eastward propagating zonal wavenumber 2 disturbance with a period near two days. This oscillation obtains a maximum amplitude of nearly 10 K in the southern hemisphere mid-latitudes during late January. The timing and location of this planetary wave is coincident with the regular quasi two-day wave intensification that occurs annually in late January. The period, wavenumber and spatial structure of the eastward propagating two-day wave are consistent with a wave that results from a nonlinear interaction between the quasi two-day wave and the migrating diurnal tide. The existence of an eastward propagating wave with a period near two days coincident with the westward propagating two day wave will have an impact on the interpretation of ground based observations. Analysis of the SABER temperature observations are utilized to determine the structure and evolution of both this eastward propagating two-day wave and the classic westward propagating zonal wavenumber 3 quasi two-day wave during January 2005.
Motor-Substrate Interactions in a Ring ATPase

Many processes in biology, including DNA recombination, prokaryotic cell-segregation, gene transposition, and viral DNA packaging, involve the translocation of DNA or RNA by ATP-driven ring motors belonging to the ASCE/AAA superfamily. While the mechanism by which these motors convert the chemical energy from ATP hydrolysis to mechanical work is beginning to be understood, little is known about how these motors engage their nucleic acid substrates. Do motors contact a single DNA element, such as a phosphate or a base, or are contacts distributed over multiple parts of the DNA? In addition, what role do these contacts play in the mechanochemical cycle? Here we use a single-molecule assay for the genome packaging motor of the Bacillus subtilis bacteriophage phi-29 to address these questions. The full mechanochemical cycle of the motor involves two phases--an ATP loading dwell followed by a translocation burst of four 2.5-bp steps. By challenging the motor with a variety of modified DNA substrates, we show that during the dwell phase important contacts are made with adjacent phosphates every 10-bp on the 5′-3′ strand in the direction of packaging. In addition to providing stable, long-lived contacts, these phosphate interactions also regulate the chemical cycle. In contrast, during the burst phase, we find that DNA translocation is driven against large forces by extensive contacts, some of which are not specific to the chemical moieties of DNA. Such promiscuous, non-specific contacts may reflect common translocase-substrate interactions for both the nucleic acid and protein translocases of the ASCE superfamily.
The Effects of Contextualization on Fluency in Three Groups of Children

This study investigated the effects of contextualization on fluency in 12 school-age children who stutter (CWS), 11 children with language impairment (CLI), and 12 children with normally developing fluency skills (CNF). Participants in the study were between the ages of 8 and 12 years and were matched for age and sex. Four discourse samples were elicited by asking participants to (a) generate two scripts related to cooking and (b) retell two stories. Having objects or pictures immediately available contextualized a cooking task and a retelling task; another set of cooking and retelling tasks were decontextualized. Moments of disfluency were identified and coded for three primary categories of disfluency: stutteringtype, normal-type, and mazing. For CWS, a significant reduction in frequency of stuttering was noted in the contextualized script generation, and mazing occurred at a significantly higher frequency than did stuttering-type or normal-type disfluencies across the four tasks. For all three groups, ...
Development and N2-Fixing Activity of the Benthic Microbial Community in Transplanted Spartina alterniflora Marshes in North Carolina

Growth and maturation of transplanted salt marshes is often limited by the availability of nitrogen (N). We examined the role of N 2 -fixing benthic microbial assemblages (microalgae and associated bacteria) in two restored marshes (1-year-old and 6-year-old marsh) and a natural salt marsh in the Newport River Estuary, North Carolina. Benthic N 2 fixation (nitrogenase activity, NA), chlorophyll a (Chl a) concentration, Spartina alterniflora (smooth cordgrass) stem counts, and sediment organic matter content were determined in the three marshes. Significant differences were observed between sites for both Chl a and NA. The 1-year-old marsh always exhibited the highest levels of NA and Chl a. Sediment organic matter content was lowest in the 1-year-old marsh (∼2%), intermediate in the 6-year-old marsh (∼5%), and highest in the natural marsh (∼10%). Carbon and nitrogen analyses were also performed on the 1-year-old marsh sediments, which were depleted in N. A positive correlation was observed between surface sediment N and Chl a. Remineralized, microbially derived N may provide growth-limiting inorganic N to Spartina transplants. N 2 -fixing microbial assemblages in the 1-year-old marsh may also be an important food source for marsh infauna. Benthic N 2 -fixing microbial assemblages play a key role in the N economy of restored salt marshes.
Synthesis of Exo-Brevicomin. Application of Organoaluminum Reagents to Synthesis

Abstract The use of hindered trialkylaluminum reagents is found to result in stereoselective reduction of the carbonyl group of 2-propionyl-6-methyl-3, 4-dihydro-2H-pyran.
Electron microscopic examination of ribosome preparations from germinated spores of Aspergillus fumigatus.

Ribosomes were isolated from germinated spores (germlings) of Aspergillus fumigatus and electron microscopy was used to determine qualitatively the extent of cellular contamination. After differential centrifugation, the initial crude preparation contained 80S ribosomes and numerous membrane contaminants in the form of membrane sheets, palisade aggregates, and vesicles 0.10–0.18 μm in size. Gel filtration chromatography of crude ribosomes in Sepharose CL-4B did not remove all of the membrane contamination. Homogenous ribosome suspensions, morphologically free of other cellular component contamination, were then obtained after gel filtration fractions were centrifuged through a 35% sucrose solution. The total ribosome yield from a germling preparation was approximately four times the yield of ribosomes from a comparable spore preparation. Gel diffusion precipitin patterns of germling ribosomes were identical to those of spore ribosomes with both germling and spore ribosomes antisera.
The Karcher mean of a class of symmetric distributions on the circle

We derive unique Karcher means for symmetric probability distributions on the unit circle, under the conditions that: (i) the distributions have differentiable density functions and (ii) the distributions are concentrated at the symmetry points.
3- to 14- μm Spectroscopy of Comet 55P/Tempel–Tuttle, Parent Body of the Leonid Meteors

Abstract Comet 55P/Tempel–Tuttle was observed between 3 an 14 μm using the Broadband Array Spectrograph System (BASS) on the NASA 3-m Infrared Telescope Facility (IRTF) on Mauna Kea. Observations were made February 8.25 and 9.25 1998 UT when the heliocentric distance of the comet was 1.03 AU and decreasing as the comet approached perihelion (February 28, 1998). The spectra from both nights showed no emission features indicative of silicates or other solid substances, and they showed no difference between the two nights. They were well fit with a 330 K blackbody between 3 and 13 μm. The 330 K color temperature was 60 K above the equilibrium blackbody temperature of 274 K. These results are somewhat unusual for a comet, because most comets show silicate emission, indicative of small olivine- and/or pyroxene-based particles. We present a simple analysis of thermal emission and show that some useful though limited knowledge can be inferred about the particles' radiative properties.
What can we learn from an unnatural immune response

In a recent review on CD8+ T-cell responses after malaria infection and immunization, Zavala and colleagues outline two decades of research and formulate the central unresolved questions in the field. Here we discuss some of these findings and highlight their importance to malaria vaccinology.
Heat Transfer in Excimer Laser Melting of Thin Polysilicon Layers

A pulsed KrF excimer laser with nanosecond pulse duration is used for surface melting of thin polycrystalline silicon films. The velocity of the moving phase boundary during melting and solidification, the maximum melting depth, as well as the melting duration are experimentally determined by combined optical and electrical methods. A melting interface tracking model is used to calculate the melt front propagation and the transient temperature field in the semiconductor. A phase-change model, which allows the occurrence of melting and solidification at temperatures other than the equilibrium melting temperature, is employed in the numerical calculation. The effect of interfacial superheating/undercooling is discussed.
Drones and fantasy in US counterterrorism

How does US Counterterrorism know that the hundreds of people killed by drones and justified as “signature” strikes (based on their pattern of life), of whom not even the names were known, are in fact actual or potential terrorists? It knows essentially by an act of fantasy. Fantasy is not understood here as equivalent to the “not-real” in some form of representational realism, but rather as constitutive of the very real. The paper examines the ways in which the fantasy surrounding the figure of “the terrorist” becomes a major component of any explanation why the president and the American public can have such a cavalier attitude toward targeted killings.
(m,n)-Equidistant Sets in $\mathbb{R}^{k},\mathbb{S}^{k}$ , and źk

We call a metric space X (m,n)-equidistant if, when A⊆X has exactly m points, there are exactly n points in X each of which is equidistant from (the points of) A. We prove that, for kź2, the Euclidean space źk contains an (m,1)-equidistant set if and only if kźm. Although the sphere $\mathbb{S}^{2}$ is (3,2)-equidistant, $\mathbb{S}^{3}$ and ź4 contain no (4,2)-equidistant sets. We discuss related results about projective spaces, and state a conjecture about $\mathbb{S}^{2}$ analogous to the Double Midset Conjecture.
The functional role of nadph-cytochrome c reductase in southern armyworm (Spodoptera eridania) midgut microsomes

A rabbit antibody was prepared against a purified protease (bromelain)-solubilized fragment of NADPH-cytochrome c reductase from microsomes of southern armyworm (Spodoptera eridania) larval midguts. The antibody cross-reacted with the reductase from both control and pentamethylbenzene-induced midgut microsomes and inhibited the NADPH-dependent, but not the NADH-dependent, reduction of artificial electron acceptors. It also inhibited microsomal epoxidation, N-demethylation and O-demethylation, thus establishing NADPH-cytochrome c reductase as an obligatory component of the electron transport pathway leading to cytochrome P-450 in midgut microsomes. SDS-polyacrylamide gel electrophoresis of the immunoprecipitate obtained by treatment of deoxycholate-solubilized microsomes with the antibody indicated that the native reductase has a mol. wt. of 80,500. The antibody to the insect enzyme exhibited no cross-reactivity towards rat liver NADPH-cytochrome c reductase and an antibody prepared to the latter was similarly inactive towards the insect enzyme.
Have ethical attitudes changed? An intertemporal comparison of the ethical perceptions of college students in 1985 and 2001

Recent ethical breeches by corporate governorsat the highest levels have called into questionwhether ethical attitudes have changed sincethe Corporate Raider scandals of the mid-1980s. We exploit a unique opportunity to follow-up ona previous investigation of college students inthe mid-1980s to analyze this question. Usinga similar survey instrument, we find thatstudents surveyed in 2001 are significantlyless accepting of the ethically questionablesituations in seven of 15 scenarios and moreaccepting in only one. Seven scenarios showedno significant change. We conclude that,overall, ethical attitudes of students in 2001appear to have become higher over time. To theextent that current students are futurebusiness leaders, we find these results to beencouraging for the long term.
Synthesis, characterization, and atropisomerism of iron complexes containing the tetrakis(2-chloro-6-fluorophenyl)porphyrinate ligand

Iron complexes of the meso-(tetraaryl)porphyrin, 5,10,15,20-tetrakis(2-chloro-6-fluorophenyl)porphine (H2ClFTPP) are reported. This unique ligand affords the opportunity to study atropisomerism in a porphyrin system containing similar substituents in the 2 and 6 positions of the meso-aryl rings. The atropisomerism displayed by the iron porphyrinates is observed to be a function of both the oxidation state of the metal and the nature of the axial ligand. In the case of iron(III) porphyrinates, a single atropisomer is favored, whereas with the iron(II) porphyrinate a statistical distribution of all possible atropisomers is observed. Variable temperature studies with the iron(II) porphyrinate demonstrate that the distribution of atropisomers is maintained even at elevated temperatures. The results are discussed in the context of atropisomerism with other meso-(tetraaryl)porphyrins.
Examining the validity and reliability of childhood abuse scales: putting The Courage To Heal to the test

Abstract Objective: The main purpose of the current study was to examine the validity and reliability of The Courage To Heal Workbook checklist (Davis, 1990) in part, through examining the internal consistency and studying whether the CTHC distinguished between the participants reporting sexual abuse histories and those who did not. Method: Two hundred and seventy-nine college students were surveyed utilizing the symptom checklist from the Courage to Heal Workbook, Trauma Symptom Checklist-40 (TSC-40), Abusive Behavior Inventory (ABI), and questions related to participants’ beliefs that they had been abused as a child. Results: Results indicated that the Courage to Heal Checklist (CTHC) has robust reliability (alpha = .97) and can significantly discriminate between reported abuse survivors and nonsurvivors. Fifty-five percent of those participants reporting sexual abuse, 47% of those reporting physical abuse, and 34% of those reporting emotional abuse indicated a period of time during which they did not remember the abuse. Conclusion: Results indicate that the CTHC reliably differentiated between participants reporting past sexual abuse and those who did not. Mounting evidence continues to support that adult symptom profiles are able to indicate that some form of trauma is likely to have occurred in the past; however, differentiating between types of abuse based on symptom profiles may be impossible. Spanish abstract was not available at time of publication.
Stepfamily Address Terms: “Sometimes They Mean Something and Sometimes They Don't.”∗

A seemingly rudimentary, but potentially significant and understudied communicative aspect of stepfamily development involves the choice of terms family members use to address one another. Ganong and Coleman (2004) argued that appropriate names for stepfamily relationships do not exist. Anthropologists and sociolinguists have long maintained, however, that the nature of personal relationships can be revealed through the use and choice of personal address terms (Beidelman, 1963; Emihovich, 1981). Therefore, in the present study we examined the use and meaning of stepfamily address terms in an attempt to understand how stepchildren use them and make sense of relational identities as well as potentially difficult stepfamily transitions. Results of 39 in-depth interviews suggest that the variety of address terms may be grouped according to formal, familiar, and familial terms and suggest stepchildren regularly engage in code-switching depending on their audience. Stepchildren reported using address terms to s...
Quantitative recovery of expired nitrogen and nitrous oxide from venous gas emboli

It has not been previously established whether venous gas emboli dissolve from pulmonary blood vessels into adjacent airways, or pass as microbubbles directly into the systemic circulation. We reported here the quantitative recovery of embolized gases from the airways, in amounts which substantiate the complete elimination of such gases by dissolution. A computer controlled quadrupole mass spectrometer was used to measure the net expired volumes of N2 or N2O following the injection of 40 ml boluses of these gases into the airways (AW) or right ventricles (RV) of 5 mongrel dogs. Every 20 ms, linearized flow signals were multiplied by gas concentrations, and the products summed for inspired and expired volumes of each breath. Intubated dogs were ventilated with 100% oxygen under Na-pentobarbital and either succinylcholine chloride or pancuronium bromide anesthesia; Swan-Ganz catheters were used for RV injections and for monotoring cardiovascular parameters. The overall mean % volume recoveries were 70.4 for AW-N2O, 68.2 for RV-N2O, 83.7 for AW-N2, and 46.7 for RV-N2. As expected, the AW percent volume recoveries increased with decreasing aqueous solubilities, and represented maximal values obtainable for RV emboli, due to alveolar reabsorption of gases excreted from the pulmonary circulation. Although all RV-N2O could thus be accounted for, RV-N2 recoveries were significantly less than AW-N2. The remaining RV-N2 did not pass as bubbles into the pulmonary veins, but continued to obstruct the pulmonary arterioles, as demonstrated with the use of nitrous oxide challenges in the inspired gas mixture.
Kinetic studies of Haemophilus influenzae malate dehydrogenase

Abstract Haemophilus influenzae malate dehydrogenase ((S)-malate: NAD + oxidoreductase EC 1.1.1.37) was purified 109-fold with a 26% recovery through a four-step procedure involving salt fractionation, hydrophobic and dye affinity chromatography. The purified enzyme was demonstrated to be a dimer of M r 61 000. Initial velocity studies of all four substrates in the forward and reverse reactions indicated a sequential mechanism for the enzyme. Product and dead-end inhibition studies were consistent with an ordered bi-bi mechanism in which NAD is the first substrate bound to the enzyme and NADH, the second product released. Several analogs of NAD structurally altered in either the pyridine moiety were observed to function as coenzymes in the reaction catalyzed by the purified malate dehydrogenase. Alterations in the purine portion of the dinucleotides had a more pronounced effect on the kinetic parameters observed in malate oxidation. The enzyme was inactivated by incubation with diethylpyrocarbonate, whereas no inactivation was observed with sulfhydryl reagents.
Life cycle and matrix analyses for re-refined Oil in Japan

Unstable market systems and consumer preferences for virgin oil have inhibited the development of waste oil re-refining in Japan. In this papery comparative life cycle inventories were developed for re-refining waste oil and for the no-refining case in which the waste oil is incinerated and needs are supplied with virgin oil. Total energy, CO2, NOx, and SO2 emissions were included during the re-refining and consumption (incineration) stages; all are lower in the case of re-refined fuel use. In addition, by using a streamlined LCA matrix, we demonstrate that re-refining waste oil can reduce environmental impacts compared with the case in which virgin oil is chosen.
Association of childhood abuse with homeless women's social networks

Abstract Objective Childhood abuse has been linked to negative sequelae for women later in life including drug and alcohol use and violence as victim or perpetrator and may also affect the development of women's social networks. Childhood abuse is prevalent among at-risk populations of women (such as the homeless) and thus may have a stronger impact on their social networks. We conducted a study to: (a) develop a typology of sheltered homeless women's social networks; (b) determine whether childhood abuse was associated with the social networks of sheltered homeless women; and (c) determine whether those associations remained after accounting for past-year substance abuse and recent intimate partner abuse. Methods A probability sample of 428 homeless women from temporary shelter settings in Los Angeles County completed a personal network survey that provided respondent information as well as information about their network members’ demographics and level of interaction with each other. Cluster analyses identified groups of women who shared specific social network characteristics. Multinomial logistic regressions revealed variables associated with group membership. Results We identified three groups of women with differing social network characteristics: low-risk networks, densely connected risky networks (dense, risky), and sparsely connected risky networks (sparse, risky). Multinomial logistic regressions indicated that membership in the sparse, risky network group, when compared to the low-risk group, was associated with history of childhood physical abuse (but not sexual or emotional abuse). Recent drug abuse was associated with membership in both risky network groups; however, the association of childhood physical abuse with sparse, risky network group membership remained. Conclusions Although these findings support theories proposing that the experience of childhood abuse can shape women's social networks, they suggest that it may be childhood physical abuse that has the most impact among homeless women. Practical implications The effects of childhood physical abuse should be more actively investigated in clinical settings, especially those frequented by homeless women, particularly with respect to the formation of social networks in social contexts that may expose these women to greater risks.
Deafferentation syndrome in the rat : effects of sex, age, and lesion type

A deafferentation syndrome can be produced in Sprague-Dawley rats following dorsal root sections. The behavior may be objective evidence of dysesthesias, thus serving as an experimental model to study chronic dysesthesias caused by deafferentation in humans. This article examines the effects of sex, age, and lesion type on the expression of the deafferentation syndrome in Sprague-Dawley rats. No significant differences were found in the expression of the deafferentation syndrome with respect to age and weight in male rats within the ranges studied. Sex and lesion type did alter the expression of the syndrome.