cssi/SciSciGPT-SciSciNet huggingface dataset:
Exploiting Partial Information in Queueing Systems

We often try to draw inferences from partial observations of queueing systems in real-life situations. For example, if we observe many customer arrivals, we may presume that the system is crowded and many customers are served. Unfortunately, such an intuitive statement is not necessarily valid. We provide sufficient conditions under which the intuition can be justified, and investigate related properties of queueing systems. We also study a way to exploit the partial information in a quantitative manner for simple queueing systems. One numerical result is rather counterintuitive. Specifically, the number of customers in the system at time t given that the cumulative number of departures is a certain constant is not necessarily stochastically increasing in t for a simple M/M/1 system with finite capacity.
Control of Dorsoventral Somite Patterning by Wnt-1 and β-Catenin

Abstract In vertebrates, the dorsoventral patterning of somitic mesoderm is controlled by factors expressed in adjacent tissues. The ventral neural tube and the notochord function to promote the formation of the sclerotome, a ventral somite derivative, while the dorsal neural tube and the surface ectoderm have been shown to direct somite cells to a dorsal dermomyotomal fate. A number of signaling molecules are expressed in these inducing tissues during times of active cell fate specification, including members of the Hedgehog, Wnt, and BMP families. However, with the exception of the ventral determinant Sonic hedgehog (Shh), the functions of these signaling molecules with respect to dorsoventral somite patterning have not been determined. Here we investigate the role of Wnt-1, a candidate dorsalizing factor, in the regulation of sclerotome and dermomyotome formation. When ectopically expressed in the presomitic mesoderm of chick embryosin ovo,Wnt-1 differentially affects the expression of dorsal and ventral markers. Specifically, ectopic Wnt-1 is able to completely repress ventral (sclerotomal) markers and to enhance and expand the expression of dorsal (dermomyotomal) markers. However, Wnt-1 appears to be unable to convert all somitic mesoderm to a dermomyotomal fate. Delivery of an activated form of β-catenin to somitic mesoderm mimics the effects of Wnt-1, demonstrating that Wnt-1 likely acts directly on somitic mesoderm, and not through adjacent tissues via an indirect signal relay mechanism. Taken together, our results support a model for somite patterning where sclerotome formation is controlled by the antagonistic activities of Shh and Wnt signaling pathways.
Calmodulin and calcium-dependent protease I coordinately regulate the interaction of fodrin with actin.

Abstract The calcium-dependent proteolysis of fodrin has been implicated in the regulation of secretion, neutrophil and platelet activation, and long-term potentiation in neurons. In vitro studies indicate that calcium-dependent protease I (calpain I) cleaves fodrin in the middle of the alpha subunit and in the COOH-terminal third of the beta subunit. Cleavage at the beta site requires calmodulin, which binds with high affinity to a single site in the alpha subunit. In vitro binding assays, nondenaturing gel electrophoresis, and velocity sedimentation identify a linkage between calcium-dependent protease I proteolysis of fodrin and the ability of calmodulin to regulate the self-association of fodrin and its interaction with actin. Three functional states appear to exist: (i) intact fodrin, which constitutively forms tetramers and binds F-actin; (ii) alpha-cleaved fodrin, which loses its ability to self-associate and bind F-actin in the presence of calmodulin; and (iii) alpha,beta-cleaved fodrin, a form that is incompetent to establish tetramers or bind actin. Because actin binding and fodrin self-association occur at opposite ends of the molecule, whereas calmodulin binds at its center, these results indicate that long-range interactions exist within fodrin. They also offer an example of how two calcium-dependent regulatory processes may act synergistically to reversibly regulate a linkage between the membrane and the cytoskeleton.
“BUT WHAT IF I SHOULD NEED TO DEFECATE IN YOUR NEIGHBORHOOD, MADAME?”: Empire, Redemption, and the “Tradition of the Oppressed” in a Brazilian World Heritage Site

In this article, I examine systems of care aimed at improving citizens and ruined colonial buildings in Salvador, Bahia, Brazil's Pelourinho World Heritage Site. Such UNESCO-sanctioned trusteeship, or the identification of buildings, bodies, and practices in need of a tutelage that would recuperate them as signs of a common humanity, maintains and exacerbates segmentations of knowledge essential to imperial control. I thus work to reconsider the Pelourinho, and cultural heritage, as imperial formations in light of UNESCO's system of producing world heritage through the specification of “exceptional universal value” in which the exceptional object obfuscates not simply as an emergency, but through its monumentalization as an ostensibly shared property. This attempt to gain a clearer understanding of empires' real effects is catalyzed by a number of residents of the Pelourinho who, in their subjection to decades of state-directed surveillance intended to make them into living human ancestors, have come to reject sentimental attachments to buildings or the purveyors of philanthropy. Yet the ways they do so are revelatory of new approaches to exceptions: Residents reject victimhood as a state of being injured and instead weave accounts of the structures that engender, and continue to reproduce, such violence. I follow in the path of this quite iconoclastic version of “historical reconstruction” as a way to draw out an ambivalently postcolonial Brazil whose own claims to exceptionality may be understood, like those put together by the woman I call Topa, as forced by entwined historical processes, rather than isolated emergencies or remainders beyond the political. My aim is to show how empires can be linked across space and time, without relying on empirical mapping of their constitutive parts and ideological props—recognizing, instead, the specificity of empire's effects.
Multiscale filter bank approach to camera-movement control in active vision systems

Active vision systems faced with the problem of searching for targets in natural scenes are finding space variant sensors increasingly important. A popular class of space variant sensors are those based on the structure of the primate retina: they have a small area near the optical axis of greatly increased resolution (the fovea) coupled with a gradual falloff in resolution as one moves towards the periphery. In such systems, a primary requirement is an efficient mechanism for targeting the optical axis to different points of interest in the visual world. In this paper, we describe a robust and efficient paradigm for achieving foveal targeting by making use of iconic scene descriptions comprised of the responses of a bank of steerable filters at multiple scales and orientations. The filter bank description is rotation and scale invariant, occlusion tolerant, and view-insensitive to a considerable extent. We describe procedures for robustly matching vectors of a previously foveated point to instances of the point in other possibly transformed images obtained after camera motion. In such situations, the multiscale structure of the filter bank lends itself naturally to an efficient targeting mechanism for the space variant sensor.
Intra-Oceanic Subduction Systems: Tectonic and Magmatic Processes

Subduction zones are locations where oceanic lithosphere, capped with altered crust and sediments, is recycled into Earth's interior. Dehydration of the subducted slab causes the generation of arc magmas with unique geochemical characteristics. The total length of active margins is about 43,500 km, and most of this length is situated on continental crust and marked by spectacular volcanoes as in the Andes and Japan. Some 17,000 km (∼40%) of volcanic arcs, are situated on oceanic crust. These intra-oceanic arcs are much less studied than their continental counterparts. The reason is that they are located in some of the world's most remote regions and their volcanoes are typically submerged below sea level. Because intra-oceanic arcs are situated on thin, mafic oceanic crust, contamination of magmas by high silica crust normally does not occur, allowing for a more straight forward investigation of mantle processes than in continental arcs. Intra-oceanic arcs are also thought to represent locations where basaltic crust is modified to form continental crust, a still poorly understood process.
Assessing Corrections to the Weighted Chi-Squared Test for Dimension

The weighted chi-squared test for dimension is an extension to the chi-squared test associated with sliced inverse regression as it lifts restrictive distributional assumptions on the predictors. Its usage requires the estimation of the mixture weights which may affect accuracy, and the computationally intensive calculation of percentiles of a mixture chi-squared distribution. The scaled and adjusted chi-squared corrections to the mixture chi-squared distribution have been proposed as alternatives to the weighted chi-squared test. A simulation study assessing power performance of the four tests indicates that the computationally simple adjusted chi-squared test could be used in place of the weighted chi-squared test, whereas the scaled chi-squared test performs much worse.
Immobilization of Clostridium thermocellum cells on bituminous coal particles.

The imobilization isotherms of Clostridium thermocellum cells on bituminous coal particles of approximately 0.15- to 0.18-mm diameter were experimentally measured at 60, 45, and 30/sup 0/C with a pH value of 7.0 and with pH values of 6.0 and 5.0 at 60/sup 0/C. The immobilization data were correlated into Langmuir forms and their characteristic coefficients were obtained. A method to obtain thermodynamic quantities, ..delta..G, ..delta..H, and ..delta..S for the immobilization is also demonstrated.
Harnessing multiple wireless interfaces for guaranteed QoS in proximate P2P networks

We consider the problem of content distribution to a group of cooperative wireless peer devices that desire the same block of information. The QoS metric is that peers are all required to receive the block by a fixed deadline, with a certain target probability. The block is divided into chunks, which are received via two methods that can be used simultaneously — (i) the B2P (base-station-to-peer) network: each peer has an unreliable, expensive, unicast channel to a cellular base station, and (ii) the P2P (peer-to-peer) network: peers can share the content over a free, lossless internal wireless broadcast network. Chunks are coded using random linear codes to alleviate the duplicate chunk reception issue. We seek an algorithm that can attain the QoS metric at the lowest cost of using B2P network. We transform the problem into two questions of (i) deciding which peer should broadcast on the P2P channel at each time, and (ii) how long B2P transmissions should take place. We use dynamic programming and queueing ideas to show that for large field sizes, a combination of Max-Rank-First and Non-min-Rank-First policies for P2P transmissions is optimal, and determine the stopping time for B2P transmissions using a Markov chain model. We provide performance bounds for finite field sizes, and illustrate our insights using simulations.
Untimely Acts: Extending the Interactionist Conception of Deviance

Interactionists and labelling theorists have made actors central to a jointly constructed process of deviance. This article extends their arguments to the deviant act itself and suggests how uses a...
Self-assembly fronts in collision: impinging ordering organosilane layers

Colliding autocatalytic wave-fronts of self-assembling organosilane (OS) layers are generated through the controlled positioning of sources of the volatile OS material at the edges of a silica wafer and through adjustment of the container dimensions in which the wafer sources are placed. The concentration profiles and molecular orientation of the OS colliding wave-fronts are assessed by means of combinatorial near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. For systems involving self-assembly wave-fronts developing from the same OS precursor molecule, the shapes of interfacial region arising from front collision are centro-symmetrical and slowly ‘heal’ to form a uniform OS layer. In contrast, heterogeneous systems, involving OS molecules having different chemistries exhibit different rates of advance and highly non-symmetrical concentration profiles after front collision. We discuss the general nature of our OS colliding front data in terms of a mean field model of colliding reaction–diffusion fronts that generalizes a model introduced before for describing single OS front propagation.
Shift in location of pygmy rabbit (Brachylagus idahoensis) habitat in response to changing environments

We show how land use and potential climate changes occurring in sagebrush communities in the Great Basin of North America are affecting the pygmy rabbit, a sagebrush obligate species. We revisited 105 sites where pygmy rabbits were collected before 1950 and determined the current presence of the species using infrared-triggered camera surveys. Pygmy rabbits were present at 36% of the sites. Fourteen percent of the sites showed signs of pinyon–juniper woodland encroachment, with only one of these sites still harboring pygmy rabbits. Sites also showed current evidence of fires (16%), urbanization (13%), and agricultural conversion (6%). At a local scale, fire frequency reduction due to livestock grazing and fire suppression have shifted pygmy rabbit habitat to lower elevations. However, overall there was more extirpation at lower elevation sites, and the increase in mean elevation of 157 m closely corresponded to the predicted elevation increase with the rise in average global temperature seen over the last century. Warming temperatures may continue to raise lower elevation boundaries of habitable sites, while higher elevation sites are being increasingly impacted by pinyon–juniper encroachment. Predicted warming temperatures also may engender greater wildfire frequencies exacerbating habitat loss, the greatest threat to pygmy rabbit persistence.
Fracture and fatigue crack-growth behavior of single crystal NiAl

Abstract The plane strain fracture toughness for pre-cracked, single crystal NiAl + 0.25%Fe was determined to be -6.5 MPa√m for the {110}tǑOl〉 crack orientation. The fatigue crack-growth behavior for this orientation was also studied. Fractography indicates the possibility of fatigue crack propagation on planes other than the preferred cleavage plane. Fatigue on these alternate planes also resulted in increased plastic deformation on the fracture surface. Finally, the transient crack-growth response following compressive overloads have been shown to be effective in reinitiating fatigue crack-growth. This effect may be due to a reduction in shielding from roughness induced crack closure.
Integrating Functional Neuroimaging and Human Operant Research: Brain Activation Correlated with Presentation of Discriminative Stimuli.

Results of numerous human imaging studies and nonhuman neurophysiological studies on "reward" highlight a role for frontal, striatal, and thalamic regions in operant learning. By integrating operant and functional neuroimaging methodologies, the present investigation examined brain activation to two types of discriminative stimuli correlated with different contingencies. Prior to neuroimaging, 10 adult human subjects completed operant discrimination training in which money was delivered following button pressing (press-money contingency) in the presence of one set of discriminative stimuli, and termination of trials followed not responding (no response-next trial contingency) in the presence of a second set of discriminative stimuli. After operant training, subjects were instructed to memorize a third set of control stimuli unassociated with contingencies. Several hours after training, functional magnetic resonance imaging was performed while subjects viewed discriminative and control stimuli that were presented individually for 1,500 ms per trial, with stimulus presentations occurring, on average, every 6 s. Activation was found in frontal and striatal brain regions to both sets of discriminative stimuli relative to control stimuli. In addition, exploratory analyses highlighted activation differences between discriminative stimuli. The results demonstrate the utility of coupling operant and imaging technologies for investigating the neural substrates of operant learning in humans.
Black-White Housing Segregation in the City of St. Louis A 1988 Update

Data from the 1988 St. Louis Dress Rehearsal Census are used to measure trends in residential segregation between decennial censuses. From 1940 through 1980, St. Louis city exhibited a persistent pattern of segregation, and through 1980, an exceptionally high proportion of its white population lived in exclusively white areas. Between 1980 and 1988, segregation declined significantly at both the tract and block levels and interracial exposure increased, suggesting a decline in the propensity of whites to move out of all-white areas that become minimally integrated. There was an overall decline in white out-migration from the city, implying that citywide net migration influences neighborhood integration potential. Still, St. Louis remains quite segregated compared to 1980 national averages.
Laser spectrum in nitrous sulphide

Abstract Nitrous sulphide (N 2 S) is identified as a carrier in a previously reported laser. A selection rule is given for the transfer of energy. N 2 S is probably a by-product of the combustion of coal.
A denaturant-insoluble form of tyrosine hydroxylase in PC12 pheochromocytoma cells

A 6M urea-insoluble form of tyrosine hydroxylase (THi) was detected in PC12 pheochromocytoma cells by western blotting immunodetection methods, and the characteristics and mechanisms of formation of this insoluble species were investigated. THi accounts for about 4% of the immunodetectable tyrosine hydroxylase in exponentially dividing pheochromocytoma cells. It is unlikely that a subpopulation of dead or dying cells is the source of THi since essentially no changes in THi levels were detected when cell death was intentionally increased. To measure the kinetics of formation of cellular THi, exponentially dividing cells were metabolically labeled first with [3H]leucine and then with [14C]leucine, and though both3H and14C were incorporated into soluble tyrosine hydroxylase, the near absence of14C in THi demonstrated that a lag period of at least a day exists between biosynthesis of tyrosine hydroxylase and the accumulation of measurable THi. The cellular accumulation of THi can evidently be regulated by the cell, since upon nerve growth factor (NGF) treatment of cells the total content of tyrosine hydroxylase increased and the content of THi decreased to yield, overall, a fivefold lower proportion of THi after 4 days. A large increase in urea-insoluble enzyme was found upon sublethal exposure of cells to ferrous ion and hydrogen peroxide, indicating that oxidative damage via metal-ion-catalyzed formation of hydroxide free radical can yield an enzyme that is similar in its insolubility to THi.
Simian immunodeficiency virus infection of macaque primary placental cells.

We have characterized the ability of a simian immunodeficiency virus, SIVmne strain E11S, to infect macaque placental trophoblast and Hofbauer cells. These primary placental cells were permissive to SIVmne infection, regardless of gestational age. Virus production by the infected cells was determined as time-dependent viral core antigen p27 production, followed by verification of the proviral gag/LTR DNA sequences in the infected cells using a polymerase chain reaction assay. Of more than six placentas tested, SIVmne infection of placental cells at an early gestational age (i.e., days 55 or 78) produced more than 10-fold the amount of virus core antigen p27 than did placental cells infected at a late gestational age (i.e., days 135 or 165). In addition, SIVmne infection of trophoblast cells was inhibited by SIVmac neutralizing macaque serum but not by normal serum, indicating the specificity of virus infection. Furthermore, the amount of SIV core antigen p27 produced by the virus-infected trophoblast and Hofbauer cells was shown to be dependent on the multiplicity of virus infection. Collectively, our results indicate that macaque trophoblast and Hofbauer cells can be infected by SIV and that both gestational age and viral dose may play a role in the extent of viral infection.
Expression of Major Histocompatibility Complex Antigens and Serum Neutralizing Antibody in Murine Retroviral Encephalitis

Murine leukemia virus infection serves as a model for noninflammatory degeneration of the central nervous system (CNS). During the course of infection with either of the molecularly cloned viruses pNE-8 or ts-1, we observed that ts-1 spread twice as rapidly as pNE-8, and ascended higher in the neuraxis. Endothelial cells were infected first, followed by oligodendrocytes and neurons, while astrocytes containing glial fibrillary acidic protein were not infected. Additionally, ts-1 also infected macrophages/microglia. Major histocompatibility complex (MHC) class I β2-microglobulin expression was minimal in pNE-8 infected mice, while it was elevated in endothelial cells of early ts-1 lesions, and in macrophages/microglia during later stages. Occasional infected cells expressed β 2-microglobulin while rare endothelial and parenchymal cells expressed MHC class II in both viral infections. Limited intra-CNS MHC expression may be one of the mechanisms of viral persistence and will present a barrier to developing immunotherapy for CNS retroviral infections. The few mice that escaped lethal infection had higher serum titers of neutralizing antibodies and showed no neuropathologic changes or detectable virus in the CNS. Higher titers of neutralizing antibodies may protect the CNS from infection.
An investigation into the role of hydroxyl radical in xanthine oxidase-dependent lipid peroxidation

Abstract A model lipid peroxidation system dependent upon the hydroxyl radical, generated by Fenton's reagent, was compared to another model system dependent upon the enzymatic generation of superoxide by xanthine oxidase. Peroxidation was studied in detergent-dispersed linoleic acid and in phospholipid liposomes. Hydroxyl radical generation by Fenton's reagent (FeCl2 + H2O2) in the presence of phospholipid liposomes resulted in lipid peroxidation as evidenced by malondialdehyde and lipid hydroperoxide formation. Catalase, mannitol, and Tris-Cl were capable of inhibiting activity. The addition of EDTA resulted in complete inhibition of activity when the concentration of EDTA exceeded the concentration of Fe2+. The addition of ADP resulted in slight inhibition of activity, however, the activity was less sensitive to inhibition by mannitol. At an ADP to Fe2+ molar ratio of 10 to 1, 10 m m mannitol caused 25% inhibition of activity. Lipid peroxidation dependent on the enzymatic generation of superoxide by xanthine oxidase was studied in liposomes and in detergent-dispersed linoleate. No activity was observed in the absence of added iron. Activity and the apparent mechanism of initiation was dependent upon iron chelation. The addition of EDTA-chelated iron to the detergent-dispersed linoleate system resulted in lipid peroxidation as evidenced by diene conjugation. This activity was inhibited by catalase and hydroxyl radical trapping agents. In contrast, no activity was observed with phospholipid liposomes when iron was chelated with EDTA. The peroxidation of liposomes required ADP-chelated iron and activity was stimulated upon the addition of EDTA-chelated iron. The peroxidation of detergent-dispersed linoleate was also enhanced by ADP-chelated iron. Again, this peroxidation in the presence of ADP-chelated iron was not sensitive to catalase or hydroxyl radical trapping agents. It is proposed that initiation of superoxide-dependent lipid peroxidation in the presence of EDTA-chelated iron occurs via the hydroxyl radical. However, in the presence of ADP-chelated iron, the participation of the free hydroxyl radical is minimal.
Impact of Early Sodium Supplementation on Hyponatremia and Growth in Premature Infants A Randomized Controlled Trial

Background: We tested the hypothesis that sodium supplementation in early preterm infants prevents late-onset hyponatremia and improves growth without increasing common morbidities during birth hospitalization. Materials and Methods: This was a randomized, masked controlled trial of 4 mEq/kg/d of sodium (intervention) versus sterile water (placebo) from days-of-life 7 to 35 in infants born at <32 weeks corrected gestational age. The primary outcome was weight gain in the first 6 weeks of life. Secondary outcomes included weekly serum sodium concentrations, growth in body length and head circumference, and complications of prematurity during birth hospitalization. Results: Fifty-three infants with an average corrected gestational age of 28.5 ± 2.4 weeks were randomized. Infants receiving the intervention had fewer (P = .012) reports of serum sodium concentrations <135 mmol/L and greater velocity of weight gain during the study period, mean (SD) 26.9 (3.1) vs 22.9 (4.7) g/kg/day, P = .012. At 6 weeks of age...
Critical Properties of Isotropically Interacting Classical Spins Constrained to a Plane

High-temperature expansions of the susceptibility and internal energy (specific heat) are presented for general lattice structure for a system of isotropically interacting unit vectors (or "classical spins") which are constrained to lie in a plane. A phase transition (${T}_{c}g0$) is indicated for two-dimensional lattices; the expected result ${T}_{c}=0$ is found in one dimension, but only upon choosing a more suitable expansion parameter than $\frac{J}{\mathrm{kT}}$. Similarities with the corresponding expansions of the $S=\frac{1}{2}$ Ising and classical Heisenberg models are pointed out; in particular, it is found that certain critical properties of this planar model appear to be bounded on one side by the Ising model and on the other side by the Heisenberg model.
Three dimensional single molecule localization using a phase retrieved pupil function

Localization-based superresolution imaging is dependent on finding the positions of individual fluorophores in a sample by fitting the observed single-molecule intensity pattern to the microscope point spread function (PSF). For three-dimensional imaging, system-specific aberrations of the optical system can lead to inaccurate localizations when the PSF model does not account for these aberrations. Here we describe the use of phase-retrieved pupil functions to generate a more accurate PSF and therefore more accurate 3D localizations. The complex-valued pupil function contains information about the system-specific aberrations and can thus be used to generate the PSF for arbitrary defocus. Further, it can be modified to include depth dependent aberrations. We describe the phase retrieval process, the method for including depth dependent aberrations, and a fast fitting algorithm using graphics processing units. The superior localization accuracy of the pupil function generated PSF is demonstrated with dual focal plane 3D superresolution imaging of biological structures.
Fusing rate-specific SVM Classifiers for ±1 embedding steganalysis

Steganography techniques can be used to convey hidden information. If done well, the information is difficult to discover and is unknown to an observer. The detection of steganography, known as steganalysis, is an important research pursuit. In previous work, we developed a method of steganalysis for images with messages embedded by an LSB plusmn1 scheme. Our method uses lossless image compression to generate statistics that are fed into a support vector machine (SVM) to classify an image as containing steganography or not. In the initial work, we trained the classifiers using images with a fixed embedding rate. However, it is not realistic to assume knowledge of the potential embedding rate of a suspect image; therefore we introduced the concept of a global classifier trained on multiple embedding rates. In this paper, we propose fusing multiple rate-specific SVMs in an attempt to improve upon the performance of the global classifier. SVM parameters from the rate-specific classifiers (e.g., distance from each models hyperplane) are used as input to the fusing classifier. We demonstrate the performance of this technique and compare it to that of the rate-specific classifier and the global classifier.
A computer program to optimize magnets in a beam transport system

A computer program that optimizes the locations and strengths of magnets in a beam transport system has been written for the IBM 704 and 7090 computers. In this program, the computer itself examines the characteristics of the emergent beam and varies the parameters of the system to optimize it. The linear theory is assumed in the program and beam separators are not included. The system has been used to prepare several experimental beams at the Cosmotron and the Brooknaven AGS. (A.G.W.)
Comment on “Using ecological thresholds to evaluate the costs and benefits of set-asides in a biodiversity hotspot”

Banks-Leite et al. (Reports, 29 August 2014, p. 1041) conclude that a large-scale program to restore the Brazilian Atlantic Forest using payments for environmental services (PES) is economically feasible. They do not analyze transaction costs, which are quantified infrequently and incompletely in the literature. Transaction costs can exceed 20% of total project costs and should be included in future research.
Measurement of trace isotopes by photon burst mass spectrometry

Progress is reported on the development of a new laser- and mass spectrometer- based technique for measurement of trace levels of radioisotopes. Significant results to date include the demonstration of high efficiency and throughput in a mass spectrometer, efficient production of metastable atoms from Ar+ and Kr+ beams, a demonstration of the photon burst detector principle with Mg+ ions, and the verification of zero background in a two- detector system.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
On the thermal properties of Martian fines

Theoretical models are developed for the thermal conductivity of grains smaller than 30 microns diameter and over 1 mm diameter in order to aid in the understanding of the thermal inertia of the surface regolith of Mars. The thermal inertia is a function of the thermal conductivity of the surface materials, and is discussed in terms of pore sizes below and above the mean free path of gas molecules (GMFP). The models are limited to surface deposits which consist of non-bonded materials at Martian surface pressures. The calculations indicate that a particulate surface with grains having pores smaller than the GMFP will be proportional to the pore or grain size. The thermal conductivity of a surface made of grains larger than the GMFP will be independent of the particle size. The results for the larger grain sizes is supported by available laboratory data. Further experiments are recommended in order to test the validity of the models for the smaller grain surfaces.
Bubble size in horizontal pipelines

Bubble sizes for dilute dispersion in horizontal pipelines under turbulent liquid flow conditions are shown to be predicted by a theory. This theory contains the dependence of dispersed-phase density on the bubble size, which is not included in theories presented by others. Theories are compared using experimental data from both gas-liquid and liquid-liquid dispersions to show that only one theory can predict both gas bubble and liquid drop sizes with a single constant. Additionally, a generalized equation is proposed that includes the effect of the dispersed-phase viscosity.
Ocular and stabilization feedback: an evaluation of two EMG biofeedback control procedures.

This study evaluated the adequacy of two novel EMG biofeedback control procedures. During a single training session, 36 subjects received either (1) contingent EMG feedback from the frontal region (Veridical), (2) contingent feedback for vertical eye movements (Ocular), or (3) a feedback condition where the signal increased with deviations in any direction from baseline EMG levels (Stabilization). The results supported the use of Ocular but not Stabilization feedback as a control procedure in frontalis EMG biofeedback studies. Ocular feedback did not produce reductions in frontalis EMG but did lead to changes in subjective measures of nonspecific treatment effects that were at least comparable to those obtained with Veridical feedback. Stabilization subjects produced small but significant reductions in EMG, felt the most bored as a result of their feedback training, and were the most likely to rate themselves as having received false feedback. The implications of attribution theory and multiprocess relaxation theory for the evaluation of nonspecific treatment effects are discussed.
Tissue water and intracellular osmoregulation in two species of euryhaline teleosts, Culaea inconstans and Fundulus diaphanus.

Abstract 1. Tissue water, chloride space, and intracellular osmotic constituents of the muscle of Culaea inconstans and Fundulus diaphanus acclimated in distilled water and various salinities of sea water for 96 hr at 20 ± 1°C were determined. 2. Tissue water increased with increasing salinity in C. inconstans , but remained constant in F. diaphanus at all salinities. 3. At the highest salinites tolerated, chloride space increased in both species, apparently because of shifts in body water from the intracellular to the extracellular phase. 4. Free ninhydrin-positive substances (NPS) play an active role in intracellular osmoregulation in F. diaphanus , but not in C. inconstans .
Acute lymphoblastic leukaemia in a child with familial Pelger-Huet anomaly.

Summary A case of familial Pelger-Huet anomaly in a 3-year-old boy with acute lymphoblastic leukaemia is described. This unique association was investigated through serial observations of the peripheral blood smear and bone marrow obtained during the child's treatment with chemotherapy. The average lobe index (ALI) of neutrophils was 1·42 with no three-lobed forms at the time of the initial diagnosis. During antimetabolite maintenance therapy with 6-mercaptopurine and methotrexate the ALI was 1·87 and three-lobed forms were present. The behaviour of the P-HA cells to heat induced radial hypersegmentation of the nucleus was examined in other family members. The mechanism by which heat and folate deficiency induce neutrophil segmentation is preserved in the familial Pelger-Huet anomaly.
Gastrointestinal basic science 2002-2003: the year in review.

Abstract The Board of Editors of Gastroenterology identified 6 topics in basic gastroenterology research in which exciting advancements have been made during the past year. These topics are (1) NOD2 variants in Crohn's disease, (2) Heliobacter pylori and CagA and VacA pathogenesis, (3) β-catenin function in normal colonic epithelia and colon cancer, (4) DNA methylation in colonic cancer, (5) the HCV replicon, and (6) the use of small interfering RNA in somatic cell genetics. Basic research in gastroenterology has been characterized during the past year by the rapid translation from fundamental research into pathophysiological systems. New technological advances are being applied to difficult areas of gastrointestinal research. Well-defined patient populations are critical to extend the knowledge derived from the human genome to gastrointestinal diseases.
Oh, give me a home: diasporic longings of home and belonging

The conversations surrounding an ephemeral home – left behind decades ago or perhaps never even visited – always and continually begs the question: why? Why do we constantly talk about geographies to which we have little or no connection with such nostalgia and fervor? Why do immigrants pick a distant space and mark that territory as home, even as we settle into the spaces we presently occupy and slowly begin the journey toward some form of assimilation? Framed by these questions, this essay attempts to articulate – through a multi-site analysis including interviews, literary and media texts – how identities are shaped through – and in relation – to the nostalgic longings of non-white immigrant experiences. The essay contends that this nostalgic longing is constructed as a response to racial relationships in the United States that identifies non-white, in this instance South Asian Americans, as aliens and others who should go back home.
The Deepest Cut: Political Ecology in the Dredging of a New Sea Mouth in Chilika Lake, Orissa, India

This paper explores the political and historical ecology surrounding the 2002 dredging of a new sea mouth in Chilika Lake, India. It contends that the use of Geographic Information Systems (GIS) and mathematical flow models advanced an 'environmental orthodoxy' that coalesced around the narrative of a rapidly 'shifting sea mouth'. This orthodoxy ignored historical evidence of the importance of seasonal flooding to the ecosystem's health and discounted the fishing communities' concerns regarding the introduction of prawn aquaculture. The product of over two centuries of flood control policies, this hydrological intervention has freed up waterlogged soils for cultivation and produced favourable conditions for the further spread of prawn aquaculture in the lake. While ostensibly engineered to improve the lake's ecology and benefit the fishing communities, this paper argues that the much-touted intervention has unsettled a slew of ecological relationships and primarily benefited the lake's agricultural communities. Most recently, unanticipated declines in the fishery have led to calls for further studies and government interventions. This research contends that successive attempts to engineer solutions for Chilika and its watershed are precisely what necessitate additional interventions. At the same time, it questions the Indian government's claim that the dredging of a new sea mouth was both necessary and scientifically sound.
The Spectrum of Pulmonary Sequestration

Abstract An intralobar sequestration with the unusual anatomical finding of both pulmonary and systemic (azygos) venous drainage is presented in detail. A review of the literature pertaining to pulmonary sequestration revealed a continuum of lung anomalies in which nearly every combination of pulmonary and systemic arterial supply, pulmonary and systemic venous drainage, normal and abnormal pulmonary tissue, gastrointestinal fistula, and defective diaphragm was described. Since no single anatomical mechanism can account for all these anomalies, the spectrum can best be explained at this time as a defect or defects of morphogenesis in the embryonic thorax. The surgeon must be aware of this spectrum of anomalies in order to remain alert to the possibility of unusual blood vessels and gastrointestinal fistula during operation for any cystic or suppurative lesion of the lungs.
Sympathetic Nerves and Myocyte Necrosis More Than Meets the Eye

The left ventricle is richly supplied with sympathetic nerves, which are spatially localized next to cardiac myocytes in a fashion that permits the rapid transmission of autonomic signals via the release of norepinephrine. Previous investigation in the heart has largely focused on the local release and reuptake kinetics of norepinephrine in conjunction with its downstream receptor-mediated events. Nevertheless, accumulating data indicate that the crosstalk between myocardial sympathetic nerves and cardiac myocytes appears to be much more complex. In addition to the co-release of other vasoactive peptides such as neuropeptide Y, sympathetic nerves can also modulate the expression of trophic factors such as nerve growth factor (NGF) and are a potential source of nitric oxide (NO) production via the neuronal NO synthase. Collectively, these can have diverse chronic effects on target tissues such as the heart, which could alter endogenous free radical scavenging mechanisms in pathophysiological states1 as well as the expression of ion channels involved in depolarization and repolarization.2 The loss of this crosstalk could alter the myocyte response to ischemia. In this issue of Circulation Research , Huang and colleagues3 provide provocative in vivo experimental data to support the notion that the sympathetic nerves modulate oxidant-mediated injury to the heart after ischemia. Chronically instrumented swine with regional sympathetic denervation were subjected to short-term hibernation using a 40% reduction in blood flow for 90 minutes followed by reperfusion for 4 days. Although flow and function were similarly matched during ischemia, the regionally denervated heart developed greater myocardial stunning than the innervated heart. Furthermore, while short-term hibernation was a reversible insult in the innervated heart, denervated animals developed histological evidence of neutrophil infiltration and micronecrosis when examined 4 days after reperfusion. This was accompanied by enhanced 3-nitrotyrosine activation in myocytes examined 1 hour after reperfusion. Protein nitration and …
Site-directed Mutagenic Alteration of Potential Active-site Residues of the A Subunit of Escherichia coli Heat-labile Enterotoxin EVIDENCE FOR A CATALYTIC ROLE FOR GLUTAMIC ACID 112

Abstract Escherichia coli heat-labile enterotoxin (LT) and the related cholera toxin exert their effects on eukaryotic cells through the ADP-ribosylation of guanine nucleotide-binding proteins of the adenylate cyclase complex. The availability of the crystal structure for LT has permitted the tentative identification of residues that lie within or are vicinal to a presumptive NAD-binding site and thus may play a role in substrate binding or catalysis. Using a plasmid clone encoding the A subunit of LT, we have introduced substitutions at such potential active-site residues and analyzed the enzymatic properties of the resultant mutant analogs. Enzymatic analyses, employing both transducin and agmatine as acceptor substrates, revealed that substitutions at serine 61, glutamic acid 110, and glutamic acid 112 resulted in reduction of enzyme activity to <10% of wild-type levels. Kinetic analyses indicated that alteration of these sites affected the catalytic rate of the enzyme and had little or no effect on the binding of either NAD or agmatine. Of the mutant analogs analyzed, only glutamic acid 112 appeared to represent an essential catalytic residue as judged by the relative effects on k and k/K. The results provide formal evidence that glutamic acid 112 of the A subunit of LT represents a functional homolog or analog of catalytic glutamic acid residues that have been identified in several other bacterial ADP-ribosylating toxins and that it may play an essential role in rendering NAD susceptible to nucleophilic attack by an incoming acceptor substrate.
Effect of essential oil and chlorhexidine mouthwashes on gingival fibroblast survival and migration.

Background: Chemical plaque control is the most commonly recommended means of oral hygiene after periodontal surgery. Commercially available mouthwashes contain a variety of active ingredients that have bactericidal properties but may potentially be toxic to the host cells. The goal of this in vitro study is to investigate the effect of commercially available mouthwashes on the survival and migratory capacity of human fibroblasts.Methods: Human gingival and periodontal ligament (PDL) fibroblasts were treated with commercially available mouthwashes that contained either chlorhexidine (CHX) or essential oils (EO) as the active ingredient. Each mouthwash was tested over a range of concentrations for its ability to affect fibroblast survival and migration, as well as long-term effects on cell viability.Results: Undiluted mouthwashes induced near-complete cell death 24 hours after only a 60-second treatment. Dilutions of 15% to 20% for both CHX and EO mouthwashes resulted in 50% cell death. When diluted to 10%...
Achievement-Related Perceptions of Children with Learning Disabilities and Normal Achievement Group and Developmental Differences

Self-perceptions of teacher feedback, social comparison of reading competence, reading satisfaction, and general self-worth were assessed among third and sixth graders with learning disabilities and normal achievement (n = 247). Relations among these variables and mean differences were examined within and across grades. As predicted, in both grades teacher feedback was the most common criterion children used to judge their academic performance. In both achievement groups, perceived teacher feedback and reading satisfaction were less favorable among sixth than third graders. Hierarchical regression analyses showed that perceived teacher feedback was the best predictor of reading satisfaction; however, in sixth grade, social comparison also contributed significantly to the prediction. The importance of perceived feedback also was demonstrated in the relation to self-worth, which was generally positive among both achievement groups and within each grade. Through its relation to reading satisfaction, perceive...
Life stressors, mastery, and perceived partner engagement in HIV‐Risk behavior

The relationships among level of personal mastery economic stress number of sexual partners pregnancy status and perceived partner engagement in HIV-risk behaviors (i.e. intravenous drug use imprisonment and sex with other partners) were studied in a sample of 1069 single inner-city women. African American and European Americans were equally represented. We predicted that greater economic stress a lower sense of personal mastery and more sexual partners would be associated with greater perceptions of partner engagement in HIV-risk behavior. We also predicted that personal mastery would serve as a moderating variable in the presence of life stressors (e.g. being pregnant having multiple sexual partners). The findings supported the hypotheses. Women with more economic stress multiple sexual partners and lower personal mastery reported higher perceived partner engagement in HIV-risk behavior than women with lower economic stress one sexual partner and higher personal mastery. Personal mastery had a greater impact for women with multiple sexual partners and for those who were pregnant. These findings were qualified by womens ethnicity. (authors)