cssi/SciSciGPT-SciSciNet huggingface dataset:
The Spectrum Opportunity

We face today a set of policy choices that will define the landscape of the connected world and America’s place within it. The popularity of smartphones, tablets, and other mobile devices has caused demand for wireless connectivity to skyrocket. Technical improvements and network upgrades alone will not satisfy this accelerating demand; any sustainable solution will involve expanding access to spectrum for mobile data. Otherwise, limited wireless capacity could become a major drag on U.S. job creation, competitiveness, innovation, community development, and important advances in education, healthcare, and public safety.Efforts to free up new capacity have run into headwinds. The problem is not a lack of resolve but the cold reality that clearing existing licensees off the spectrum, moving them and their users somewhere else, and auctioning the frequencies to new licensees is increasingly costly, contentious, and uncertain. An approach based entirely on taking frequencies from someone and transferring them to someone else will not maximize capacity over the long term.What is needed is a change in orientation. Policy-makers should acknowledge what engineers already recognize and businesses are already implementing: The future of spectrum is about various forms of sharing. Exclusive rights are still desirable, even essential, in some contexts. However, they will exist within a larger matrix of sharing arrangements to maximize available capacity. Such a policy approach allows the most users and devices to benefit from the airwaves, rather than simply picking winners. At the same time, it will extend the long tradition of wireless communication as a mechanism for innovation and free expression.
A CULTURALLY SYNTONIC APPROACH TO THE FIELD EDUCATION OF LATINO STUDENTS

Abstract Field education is conceived of as a form of experiential learning. However, during that professional developmental process, ethnic minority students often experience cultural conflicts between their developing professional identities and their ethnic identity. Thus, the relationship between the student trainee and field work instructor is a crucial one. This article examines the components of the training process as well as the dynamics of the field instructor—Latino student trainee relationship in the context of the challenges both instructors and Latino students face in education. Challenges involve definition of the Latino social worker's role, degree of identification with the Latino culture, the other roles students play, and an understanding of the importance of family in the Latino culture. Culturally relevant instructional models are presented.
PHENETHYL ALCOHOL. II. EFFECT ON THYMINE-REQUIRING ESCHERICHIA COLI.

Rosenkranz, Herbert S. (Columbia University, New York, N.Y.), Howard S. Carr, and Harry M. Rose. Phenethyl alcohol. II. Effect on thymine-requiring Escherichia coli. J. Bacteriol. 89:1370-1373. 1965.-Phenethyl alcohol (PEA) at levels (0.05%) presumed to interfere with messenger ribonucleic acid synthesis also inhibits thymineless death, when the agent is added prior to the exponential killing phase. The addition of more concentrated solutions of PEA (0.5%) during this initial starvation leads to an immediate killing. Identical results were obtained when 0.5% PEA was added to cells growing in the presence of thymine. The addition of this high level (0.5%) of PEA to bacteria undergoing thymineless death results in the rescue of the survivors.
Neuronal adaptation to amphetamine and dopamine: Molecular mechanisms of prodynorphin gene regulation in rat striatum

Induction of prodynorphin gene expression by psychostimulant drugs may represent a compensatory adaptation to excessive dopamine stimulation and may contribute to the aversive aspects of withdrawal. We therefore investigated the molecular mechanisms by which dopamine psychostimulant drugs induce prodynorphin gene expression in vivo and in rat primary striatal cultures. We demonstrate that three recently described cAMP response elements (CREs), rather than a previously reported noncanonical AP-1 site, are critical for dopamine induction of the prodynorphin gene in striatal neurons. CRE-binding protein (CREB) binds to these CREs in striatal cell extracts and is phosphorylated on Ser-133 after dopamine stimulation in a D1 dopamine receptor-dependent manner. Surprisingly, following chronic administration of amphetamine, levels of phosphorylated CREB are increased above basal in rat striatum in vivo, whereas c-fos mRNA is suppressed below basal levels. D1 receptor-mediated CREB phosphorylation appears to mediate adaptations to psychostimulant drugs in the striatum.
Synchronous, dual-wavelength, injection-seeded amplification of 5-ns pulses in a flash-lamp-pumped Ti:sapphire laser

The outputs of two cw diode lasers are coupled into a flash-lamp-pumped Ti:sapphire laser cavity for regenerative amplification. Slices of each seed beam are simultaneously trapped in the cavity and amplified for approximately 33 round trips. The output is a 4.7-ns pulse, the total pulse energy is 110 mJ, and linewidths are only 50% greater than the Fourier-transform limit. The timing jitter between the pulses at the two wavelengths is less than ±75 ps, and their relative energy is controlled by adjustment of the seed power of the cw diode lasers. Gain competition between the two frequencies does not lead to instabilities.
The A-Fx to F(A/B) step in synechocystis 6803 photosystem I is entropy driven.

We have previously reported the enthalpy and volume changes of charge separation in photosystem I from Synechocystis 6803 using pulsed photoacoustics on the microsecond time scale, assigned to the ...
Non-Invasive Determination of Zero-Pressure Geometry of Arterial Aneurysms

Arterial aneurysms are in a pre-deformed state in vivo under non-zero pressure. The ability to determine their zero pressure geometry may help in improving accuracy of determination of stress distribution and reverse estimation of material properties from dynamic imaging data. An approximate method to recover the zero pressure geometry of the AAA is proposed. This method is motivated by the observation that the patterns in displacement field for a given AAA are strikingly consistent in an AAA under all physiological pressures. The basic principle is to leverage this observation to iteratively identify the geometry that when subjected to the in vivo pressure, will recover the geometry reconstructed from in vivo imaging. The methodology is demonstrated and validated using patient-specific AAA models.
Gravity and configurational energy induced microstructural changes in liquid phase sintering

Experiments were performed with W-Ni-Fe heavy alloys in order to measure the microstructural changes vs. position that occur in liquid-phase sintering under normal gravity. The experimentally observed segregation is less than the calculated equilibrium segregation due to the retarding effect from the rigid solid skeleton formed during sintering. These results improve understanding of microstructure, mechanical properties, component shape, and dimensional stability benefits that may be realized from low-gravity sintering.
Disruption and habituation of stable fixed-interval behavior in younger and older monkeys

Abstract Reactivity to novel and irrelevant stimuli has been shown to vary as a function of age. Since differential responsivity to irrelevant events may account for purported age differences on other tasks, the present experiment studied the extent to which these age differences may be reduced with repeated exposure, i.e., habituation. Young (2 to 3 years) and old (15+ years) squirrel monkeys were trained and their performance stabilized over months on a fixed-interval operant task. This behavior was then disrupted by periodic presentations of an auditory stimulus of moderate intensity. Disruption of stable behavior and habituation to the tone stimulus were evaluated across several measures including overall response rates between and within the daily sessions; recovery of baseline response rates during the tone stimulus; and the curvature of the fixed interval “scallop.” Old monkeys responded for sweet fruit juice more frequently, but less efficiently, than young monkeys. Their responding was more severely disrupted by intermittent novel auditory stimuli, to which they were slower to habituate.
SCEPTICISM ABOUT PHILOSOPHY

Suppose a person who is agnostic about most philosophical issues wishes to have true philosophical beliefs but equally wishes to avoid false philosophical beliefs. I argue that this truth-seeking, error-avoiding agnostic would not have good grounds for pursuing philosophy. Widespread disagreement shows that pursuing philosophy is not a reliable method of discovering true answers to philosophical questions. More likely than not, pursuing philosophy leads to false belief. Many attempts to rebut this sceptical argument fail.
Asymptotic solution to axisymmetric indentation of a compressible elastic thin film

Abstract Using the perturbation theory, the axisymmetric indentation of a compressible elastic thin film bonded to a rigid substrate is analyzed for the contact radius much larger than the thickness of the thin film. Explicit expression of the nominal contact stiffness is obtained, which is proportional to the contact area and inversely proportional to the thickness of the thin film, independent of indenter. The effect of surface interaction on the indentation of compressible elastic films is also discussed by following the Johnson–Kendall–Roberts approach. Closed-form solutions are obtained for the indentation load–indentation depth relation under the action of the surface interaction. It turns out that, for spherical indenters, the pull-off force to detach the indenter from the surface of the thin film is independent of elastic properties of the thin film. This analysis provides us a new approach to evaluate mechanical properties of ultra-thin films by using the nanoindentation technique.
Muscle Washing and Raw Material Source Affect Quality and Physicochemical Properties of Low‐salt, Low‐fat, Restructured Beef

Five percent unwashed and washed skeletal (USM and WSM) and cardiac (UCM and WCM) muscle and fish surimi (FS) were evaluated in precooked (64.4 °C), restructured beef using 0.2% NaCl. Additionally, a 0.2% NaCl product without binder and a 1.0% NaCl treatment containing 5% USM were made. Washing enhanced sensory and instrumental texture measures of products containing CM but did not affect products containing SM. UCM and WCM appeared beneficial for maintenance of product color but tended to increase lipid oxidation. Washing reduced surface hydrophobicity, decreased disulfide content of CM, increased free sulfhydryls of CM and SM, and lowered soluble protein in binder extracts. Binders did not improve product characteristics.
Does Inhibition of β-Cell Proliferation by Free Fatty Acid in Mice Explain the Progressive Failure of Insulin Secretion in Type 2 Diabetes?

Large prospective studies have shown that insulin secretion declines over time in patients with type 2 diabetes (1). This makes treatment of these patients a moving target, i.e., a regimen that works today may not work next year. The cause or causes for the progressive decrease in insulin secretion rates over time remains uncertain, but several possibilities have been proposed including amylin accumulation in β-cells (2), glucotoxicity, lipotoxicity, and glucolipotoxicity. The concept that prolonged hyperglycemia results in impaired insulin secretion (i.e., glucotoxicity) was first proposed by Unger and Grundy (3) and is now generally accepted. Lipotoxicity, defined as inhibition of insulin secretion by elevated plasma levels of free fatty acid (FFA), was also first proposed by Unger (4). It is supported by many in vitro studies but has remained controversial mainly because inhibitory effects of chronically elevated FFA levels on insulin secretion have been difficult to demonstrate in subjects with normal islets (rev. in 5). On the other hand, the combination of chronically elevated plasma glucose and FFA levels (glucolipotoxicity) has been demonstrated to inhibit insulin secretion from normal and abnormal β-cells in vivo (5–7) and in vitro (8). The article by Pascoe et al. (9) supports the …
Structure and carbonate orientation of vaterite (CaCO3)

First-principles calculations and molecular-dynamics simulations are employed in this study to further our understanding of the crystal structure and orientational order of carbonate ions in vaterite, which is the least stable polymorph of calcium carbonate. The structural details of vaterite have been controversial but they are prerequisite for investigating and understanding the processes involving vaterite crystal nucleation, growth, and stabilization at a molecular level. The first-principles calculations, using density functional theory with the plane-wave pseudopotential method, are carried out to calculate relative thermodynamic stabilities of proposed structures. Molecular-dynamics simulations with classical empirical potentials, larger computational cells, and fully flexible models at different temperatures are performed to investigate the orientation and order-disorder of the carbonate ions. The results show that the previously accepted structure with disordered CO 3 ions, which are randomly distributed over three orientations parallel to the c axis, is only metastable. By applying a temperature annealing technique to the molecular dynamics simulations, a more stable structure with fully ordered carbonate ions is found that has a hexagonal superstructure. The space group of this newly derived vaterite structure is P 6 5 22 (no. 179) with Z = 18 and cell dimensions of √3 times in a , and 3 times in c of the previous suggested disordered structure. Comparison of experimental observations of X-ray diffraction patterns, enthalpies of transformation to calcite, and volume change by heat treatment with our theoretical calculations indicates that freshly made vaterite is often carbonate-disordered and metastable and can fully or partially transform to a carbonate-ordered structure by aging and heating.
High frequency excess noise and flicker noise in GaFs FETs

Abstract The noise parameter α = R n g m , where R n is the noise resistance and g m the transconductance, was measured for n -channel GaAs FETs. At lower frequencies α varies as 1/ f , as expected for flicker noise, whereas at higher frequencies α attains a limiting value α ∞ that is larger than expected for thermal noise. Arguments are presented to show that the high-temperature value of α ∞ is due to a geometry effect, possibly aided by a temperature-independent hot electron effect, whereas the low-temperature data reflect a temperature-dependent hot electron effect. The flicker noise is practically temperature independent, and is attributed to the large interface between semiconductor and oxide.
A hybird computer programming system

In order to analyze and subsequently synthesize complex systems, engineers have increasingly turned to computer simulation techniques. Until recently, simulation techniques could generally be divided either on the basis of the type of computer to be used, or the type of system to be simulated.
Delayed effects of radiofrequency energy on accessory atrioventricular connections

The purpose of this study was to determine the incidence and characteristics of delayed effects on conduction through accessory atrioventricular (AV) connections after apparently successful attempts at radiofrequency catheter ablation. Among 450 patients who had 471 accessory AV connections, the ablation procedure was unsuccessful in 26 patients (6%), as defined by persistent conduction through the accessory AV connection 60 minutes after the final application of radiofrequency energy. In 6/26 unsuccessfully treated patient (24%), conduction through the accessory AV connection disappeared on a delayed basis. At least once during the ablation procedure, conduction through each of these 6 accessory AV connections was transiently eliminated for 10 seconds to 60 minutes. Five of these accessory AV connections were left-sided and one was posteroseptal; one was concealed and five were manifest. Conduction through the accessory AV connection disappeared on a delayed basis 6-18 hours after the ablation procedure in 4 patients, and at some time between 1-5 days or 1-60 days in the other 2 patients. In 2 patients, the delayed effect was only transient, while in 4 patients, conduction through the accessory AV connections did not return during 5-23 months of follow-up. In conclusion, up to 15% of patients who undergo an apparently unsuccessful attempt at radiofrequency ablation of an accessory AV connection may later manifest a permanent loss of conduction through the accessory AV connection.
In-Vivo Lumbar Intervertebral Disc Geometric Deformation During Functional Postures

Degeneration of the intervertebral disc is responsible for the vast majority of back pain. Significant efforts have been made to characterize lumbar intervertebral disc (IVD) deformation during physiologic functional postures in an attempt at understanding the mechanisms resulting in disc related spinal disorders and improving their surgical treatment. However, the details of IVD deformation, including the magnitude and direction of tension and shear, have yet to be clearly defined in-vivo mainly due to technical limitations. This study investigated lumbar IVD geometric deformation from translation and orientation of the adjacent level endplates using a combined MR and fluoroscopic image matching technique [1]. Tensile and shear deformation was quantified by comparing IVD deformation at flexion and extension positions to standing position at the L2-L5 vertebral levels.Copyright © 2009 by ASME
Political uncertainty's effect on judicial recruitment and retention: Japan in the 1990s

Abstract Because of the risk of political interference, in countries with managed courts, jurists who share ruling-party preferences disproportionately self-select into judicial instead of private careers. During political turmoil, such jurists will find judicial careers less attractive. Orthodox potential jurists will disproportionately shun the courts, and orthodox incumbent judges will disproportionately resign. Unorthodox potential jurists, on the other hand, might find the judiciary more attractive. Combining data on a random sample of 1605 Japanese lawyers and on all 2502 judges hired between 1971 and 2001, we locate evidence consistent with these hypotheses: after the political crisis of 1993, the recruitment of young lawyers from elite universities lagged, while the number of early resignations increased. Journal of Comparative Economics 35 (2) (2007) 329–345.
Experiments with cross-gyre flow patterns on a beta-plane

Abstract Patterns of flow are computed in a two moving layer, two gyre ocean circulation model to demonstrate how the location of a localized region of buoyancy flux determines the nature of meridional and cross-gyre buoyancy transport. The calculation is done by the method of characteristics. Problems of control of boundary conditions and location of shocks are discussed, using six examples.
Before, after, in and beyond teacher education

The author uses a trip to a Holocaust museum to explain and illustrate psychoanalytic concepts from Freud to Lacan in order to re-imagine persistent dilemmas in teacher education. The author suggests that psychoanalytic vocabularies provide an additional and productive lens to conceptualize productive possibilities in teacher education.
Histone lysine demethylases function as co-repressors of SWI/SNF remodeling activities during Drosophila wing development

Abstract The conserved SWI/SNF chromatin remodeling complex uses the energy from ATP hydrolysis to alter local chromatin environments through disrupting DNA-histone contacts. These alterations influence transcription activation, as well as repression. The Drosophila SWI/SNF counterpart, known as the Brahma or Brm complex, has been shown to have an essential role in regulating the proper expression of many developmentally important genes, including those required for eye and wing tissue morphogenesis. A temperature sensitive mutation in one of the core complex subunits, SNR1 (SNF5/INI1/SMARCB1), results in reproducible wing patterning phenotypes that can be dominantly enhanced and suppressed by extragenic mutations. SNR1 functions as a regulatory subunit to modulate chromatin remodeling activities of the Brahma complex on target genes, including both activation and repression. To help identify gene targets and cofactors of the Brahma complex, we took advantage of the weak dominant nature of the snr1E1 mutation to carry out an unbiased genetic modifier screen. Using a set of overlapping chromosomal deficiencies that removed the majority of the Drosophila genome, we looked for genes that when heterozygous would function to either enhance or suppress the snr1E1 wing pattern phenotype. Among potential targets of the Brahma complex, we identified components of the Notch, EGFR and DPP signaling pathways important for wing development. Mutations in genes encoding histone demethylase enzymes were identified as cofactors of Brahma complex function. In addition, we found that the Lysine Specific Demethylase 1 gene (lsd1) was important for the proper cell type-specific development of wing patterning.
Relaxation of the SH vibrational stretch mode in As2S3 glass

The frequency dependent relaxation properties of the SH vibrational stretch mode in hydrogen doped As 2 S 3 glass have been measured using IR picosecond laser saturation spectroscopy. A low temperature lifetime in the order of 10 -10 s is found that varies by a factor 6 across the broad SH absorption line
Note on analysis of quartz grain dimensions in foliated greywackes

Quartz grain dimensions, measured parallel to an internal reference system (reference aspect ratio, RAR), were analyzed using the »reduced major axis« (RMA) linear regression analysis. In contrast to least-squares analysis, this statistical technique does not distinguish between dependent and independent variables.
Addressing Limitations with the MM-GB/SA Scoring Procedure using the WaterMap Method and Free Energy Perturbation Calculations

The MM-GB/SA scoring technique has become an important computational approach in drug design. We, and others, have demonstrated that for congeneric molecules the correlation with experimental data obtained with the physics-based scoring is usually superior to scoring functions from typical docking algorithms. Despite showing good accuracy when applied within a series, much work is necessary to improve the MM-GB/SA method in order to gain greater efficiency in drug design. Here, we investigate the poor estimation of protein desolvation provided by the GB/SA solvation model and the large dynamic range observed in the MM-GB/SA scoring compared to that of the experimental data. In the former, replacing the GB/SA protein desolvation in the MM-GB/SA method by the free energy associated with displacing binding site waters upon ligand binding estimated by WaterMap provides the best results when ranking congeneric series of factor Xa and cyclin-dependent kinase 2 (CDK2) inhibitors. However, the improvement is mode...
Resolution of ghost imaging for nondegenerate spontaneous parametric down-conversion

We examine the resolution of a ghost imaging system for the case in which the entangled photons are nondegenerate in frequency. The signal photon illuminates the object and is detected by a bucket detector. The idler photon is detected by a point detector. We consider the two cases in which the imaging lens is in the same arm as the object and when it is in the other arm. In the first case, the Airy disk is shown to depend on the wavelength of the idler photon; however, because the magnification depends on the two wavelengths, the resolution of a pair of point scatters on the object depends on the wavelength of both photons. In cases in which the position of the object can be controlled, the minimum resolvable distance can be optimized. In the case in which the object is in the far field, the resolution depends only on the signal wavelength. In the second case, the Airy disk depends on the wavelength of both photons but the resolution depends on the signal photon. While the ghost imaging system has flexibility for certain applications, the resolution of the nondegenerate ghost imaging system does not offer improvement over the classical illumination of the object.
Tutorial Commentary: Surprisingly Small Subcortical Structures Are Needed for the State of Waking Consciousness, while Cortical Projection Areas Seem to Provide Perceptual Contents of Consciousness

The evidence can therefore be summarized as follows: (1) RF, nRt, and ILN activity seem to be necessary but not sufficient for conscious experience. (2) Stimulus representation in primary sensory projection areas also seems to be necessary but not sufficient for conscious perceptual experience (Weiskrantz, 1980). The simplest hypothesis is that both components are necessary and sufficient to support conscious perceptual experience.
On the existence of some intermediate products in the catalytic hydrogenation of lycopene.

Abstract Upon partial catalytic hydrogenation of lycopene and chromatographic resolution of the mixture, eight polyenes were present and were characterized spectroscopically. The respective principal spectral maxima were located at the following wavelengths: 470, 454, 439, 418, 395, 366, 341, and 311 mμ (in hexane). Three of the compounds have crystallized. Phytofluene and phytoene were absent.
Inhibition of lipolysis does not affect insulin sensitivity to glucose uptake in the mourning dove.

Birds have much higher plasma glucose and fatty acid levels compared to mammals. In addition, they are resistant to insulin-induced decreases in blood glucose. Recent studies have demonstrated that decreasing fatty acid utilization alleviates insulin resistance in mammals, thereby decreasing plasma glucose levels. This has yet to be examined in birds. In the present study, the levels of glucose and β-hydroxybutyrate (BOHB), a major ketone body and indicator of fatty acid utilization, were measured after the administration of chicken insulin, acipimox (an anti-lipolytic agent), or insulin and acipimox in mourning doves (Zenaidura macroura). Insulin significantly decreased whole blood glucose levels (19%), but had no effect on BOHB concentrations. In contrast, acipimox decreased blood BOHB levels by 41%, but had no effect on whole blood glucose. In addition to changes in blood composition, levels of glucose uptake by various tissues were measured after the individual and combined administration of insulin and acipimox. Under basal conditions, the uptake of glucose appeared to be greatest in the kidney followed by the brain and skeletal muscle with negligible uptake by heart, liver and adipose tissues. Acipimox significantly decreased glucose uptake by brain (58% in cortex and 55% in cerebellum). No significant effect of acipimox was observed in other tissues. In summary, the acute inhibition of lipolysis had no effect on glucose uptake in the presence or absence of insulin. This suggests that free fatty acids alone may not be contributing to insulin resistance in birds.
Firing relations of medial entorhinal neurons to the hippocampal theta rhythm in urethane anesthetized and walking rats.

The firing of neurons from layers II and III of medial entorhinal cortex (MEC) was examined in relation to the hippocampal theta rhythm in urethane anesthetized and walking rats. 1) MEC neurons showed a significant phase relation to the hippocampal theta rhythm in both walking and urethane anesthetized rats, suggesting that this region contributes to the generation of both atropine-resistant and atropine-sensitive theta rhythm components. 2) The proportion of phase-locked cells was three times greater in walking rats (22/23 cells) as compared to anesthetized rats (8/23 cells), indicating that MEC cells made a greater contribution during walking theta rhythm. This difference was also manifest in the greater mean vector length for the group of phase-locked MEC cells during walking: 0.39 ± 0.13 versus 0.21 ± 0.08. Firing rate differences between walking and urethane conditions were not significant. 3) In walking rats, MEC cells fired on the positive peak of the dentate theta rhythm (group mean phase = 5°; 0° = positive peak at the hippocampal fissure). This is close to the reported phases for dentate granule and hippocampal pyramidal cells. The distribution of MEC cell phases in urethane anesthetized rats was broader (group mean phase = 90°), consistent with the phase data reported for hippocampal projection cells.
Quantum photovoltaic effect in double quantum dots

We analyze the photovoltaic current through a double quantum dot system coupled to a high-quality driven microwave resonator. The conversion of photons in the resonator to electronic excitations produces a current flow even at zero bias across the leads of the double quantum dot system. We demonstrate that due to the quantum nature of the electromagnetic field in the resonator, the photovoltaic current exhibits a double peak dependence on the frequency $\ensuremath{\omega}$ of an external microwave source. The distance between the peaks is determined by the strength of interaction between photons in the resonator and electrons in the double quantum dot. The double peak structure disappears as strengths of relaxation processes increases, recovering a simple classical condition for maximal current when the microwave frequency is equal to the resonator frequency.
Japanese maquiladoras: Production organization and global commodity chains

Abstract During the last decade at least 66 Japanese maquiladoras have been established in Mexico employing in excess of 20,000 workers. This paper examines the organization of production in these plants and the insertion of these production activities in the global commodity chains of these firms. Managers at 17 firms were interviewed either in person or by telephone and 10 of the plants were visited. The results indicate that the production organization and labor-management relationships resembled that of temporary employees in Japan. Most of the activities undertaken in the maquiladoras are relatively low-skill level, labor-intensive activities. In Tijuana there are now at least 31 Japanese maquiladoras most of which are in the electronics industry and these include a number of Japanese suppliers, thereby creating a proto-industrial complex.
Pressure dependence of positron lifetimes in V3Si

Abstract We have measured positron lifetimes in V 3 Si at hydrostatic pressures of 0 to 20 kb, at room temperature. The lifetimes were independent of pressure, within the experimental uncertainty of ± 2 ps; the results of eight measurements all were between 129 and 133 ps.
The Structure of Two South Carolina Estuarine Tide Pool Fish Assemblages

The fish assemblages of two South Carolina estuarine tide pools located in the North Edisto River were sampled from June to October 1977, and during June and July 1978, by haul seine, lift net and channel net. The nekton was dominated numerically byFundulus heteroclitus, Leiostomus xanthurus, Menidia menidia andAnchoa mitchilli. Oyster reef areas were dominated numerically byGobiosoma bosci andF. heteroclitus. The relative abundance of tide pool fishes differs from deep water areas of the North Edisto River as described from otter trawls, but is similar to that described by others for South Carolina tidal creeks.
Rigorous channeling stability theorems

Abstract This letter states the first rigorous results on the stability of channeling trajectories of fast charged particles in crystals within the context of non-trivial two- and three-dimensional non-relativistic classical models. These results were obtained by deriving asymptotic forms of the relevant canonical maps and then applying suitable versions of Moser's twist theorem.
Evolution of antigenic determinants of transferrin and other serum proteins in primates

The antigenic determinants of the transferrins of 23 different primate species have been compared by a radioimmune inhibition of precipitation technique. Highest degrees of cross-reactivity with antisera to human transferrin were found in the transferrin of African apes, followed by that of the Asian apes, the Old World monkeys, the New World monkeys, and finally by the Prosimians. Thus, the evolution of the antigenic determinants on the transferrin molecule is in good agreement with the taxonomic classification of these species. Similar studies were carried out for α2-macroglobulin and various immunoglobulin chains. Parallel results were obtained except for the μ heavy chain of γM macroglobulin in which gibbon, orangutan, and gorilla probably followed a divergent line of evolution from the other Hominoidea.
Ca isotopes in carbonate sediment and pore fluid from ODP Site 807A: The Ca2+(aq)–calcite equilibrium fractionation factor and calcite recrystallization rates in Pleistocene sediments

Abstract The calcium isotopic compositions (δ44Ca) of 30 high-purity nannofossil ooze and chalk and 7 pore fluid samples from ODP Site 807A (Ontong Java Plateau) are used in conjunction with numerical models to determine the equilibrium calcium isotope fractionation factor (αs−f) between calcite and dissolved Ca2+ and the rates of post-depositional recrystallization in deep sea carbonate ooze. The value of αs−f at equilibrium in the marine sedimentary section is 1.0000 ± 0.0001, which is significantly different from the value (0.9987 ± 0.0002) found in laboratory experiments of calcite precipitation and in the formation of biogenic calcite in the surface ocean. We hypothesize that this fractionation factor is relevant to calcite precipitation in any system at equilibrium and that this equilibrium fractionation factor has implications for the mechanisms responsible for Ca isotope fractionation during calcite precipitation. We describe a steady state model that offers a unified framework for explaining Ca isotope fractionation across the observed precipitation rate range of ∼14 orders of magnitude. The model attributes Ca isotope fractionation to the relative balance between the attachment and detachment fluxes at the calcite crystal surface. This model represents our hypothesis for the mechanism responsible for isotope fractionation during calcite precipitation. The Ca isotope data provide evidence that the bulk rate of calcite recrystallization in freshly-deposited carbonate ooze is 30–40%/Myr, and decreases with age to about 2%/Myr in 2–3 million year old sediment. The recrystallization rates determined from Ca isotopes for Pleistocene sediments are higher than those previously inferred from pore fluid Sr concentration and are consistent with rates derived for Late Pleistocene siliciclastic sediments using uranium isotopes. Combining our results for the equilibrium fractionation factor and recrystallization rates, we evaluate the effect of diagenesis on the Ca isotopic composition of marine carbonates at Site 807A. Since calcite precipitation rates in the sedimentary column are many orders of magnitude slower than laboratory experiments and the pore fluids are only slightly oversaturated with respect to calcite, the isotopic composition of diagenetic calcite is likely to reflect equilibrium precipitation. Accordingly, diagenesis produces a maximum shift in δ44Ca of +0.15‰ for Site 807A sediments but will have a larger impact where sedimentation rates are low, seawater circulates through the sediment pile, or there are prolonged depositional hiatuses.
Monocrystal elastic constants in the ultrasonic study of welds

Abstract For studying welds ultrasonically, the importance of knowing the material's single-crystal elastic constants, the C ij s, is explained. Where these constants are not known, some guidelines are given for estimating them from polycrystalline elastic constants such as Young's modulus and the shear modulus. The important case of [001] fibre texture is considered. Being transversely isotropic, this case exhibits five macroscopic elastic constants, which are related to the three cubic elastic constants: C 11 , C 12 , C 44 . From these five constants the angular variations of Young's modulus, the torsional modulus, and the sound velocities can be computed. For the same [001] fibre texture, results are given for a standard well-characterized material — copper, where the C ij s are well known.
Differential activation of an identified motor neuron and neuromodulation provide Aplysia's retractor muscle an additional function

To survive, animals must use the same peripheral structures to perform a variety of tasks. How does a nervous system employ one muscle to perform multiple functions? We addressed this question thro...
An observational note on eye movement patterns during REM and non-REM sleep in subjects with congenital nystagmus.

Fully developed nystagmus present in five Ss with congenital nystagmus while awake with eyes open or closed did not appear during the REM or non-REM sleep phases. However, rapid conjugate eye movements were present during REM sleep in all five Ss, and could not be distinguished from the patterns recognized in normal subjects.
Do hypertensive patients have a different diurnal pattern of electrolyte excretion

Studies generally indicate that excretion of sodium, potassium, and water is greater during the day than during the night. To determine whether hypertensive patients exhibit this same pattern of excretion, diurnal variations in excretion of sodium, potassium, creatinine, and water were examined in 107 hypertensive men and women from a clinical trial on control of hypertension by nonpharmacological means--the Hypertension Control Program. Each participant provided two carefully timed 24-hour urine collections divided into daytime and overnight specimens. The median ratios of 24-hour to 8-hour overnight excretion were 2.84, 3.95, 2.99, and 2.77 for sodium, potassium, creatinine, and water, respectively. Thus, more than half of this hypertensive group exhibited a greater rate of sodium and water excretion during sleep than during daytime hours, a reversal of the usual pattern. When the group was subdivided based on age, sex, race, trial randomization group, use of diuretics, and hypertension severity, women had significantly lower ratios of 24-hour to overnight excretion for sodium and water than men and blacks had significantly lower 24-hour to overnight ratios for water and potassium than whites. When the 24-hour to overnight ratios for these hypertensive patients were compared with those for a group of 30 men and women with high-normal blood pressure, those with high-normal blood pressure had significantly larger ratios for sodium and water excretion than the hypertensive group. The results of this study suggest that hypertensive patients may have a different diurnal pattern of sodium and water excretion than normotensive subjects and that further research is needed to clarify this issue.
Effects of stress-driven melt segregation on the viscosity of rocks

Abstract We present rheological data on samples of partially molten mantle rocks deformed in torsion at 1200 °C and 300 MPa in a gas-medium deformation apparatus. Samples in which stress-driven melt segregation occurs are significantly weaker than those with a homogeneous melt distribution, with strain rate increased by up to a factor of 6. The degree of melt segregation, which is influenced by the permeability of the sample material (and hence the compaction length), is controlled by changing chromite fraction as a minor solid second phase. In general, a higher degree of melt segregation causes a greater strain rate enhancement. Although we focus here on the steady-state rheological properties, a simple model of the evolution of melt segregation and rheological properties is presented. This model fits well the latter part of the stress–strain evolution but fails to fit the early, transient stages of deformation. One implication is that weakening occurs very quickly due to the emergence of smaller-scale melt bands. The model (constitutive and evolution equations) is designed to be incorporated into geodynamic-scale continuum models to explore the effects of segregation without resolving the length scales of the process directly.
PheMaDB: a solution for storage, retrieval, and analysis of high throughput phenotype data.

OmniLog™ phenotype microarrays (PMs) have the capability to measure and compare the growth responses of biological samples upon exposure to hundreds of growth conditions such as different metabolites and antibiotics over a time course of hours to days. In order to manage the large amount of data produced from the OmniLog™ instrument, PheMaDB (Phe notype M icroa rray D ataB ase), a web-based relational database, was designed. PheMaDB enables efficient storage, retrieval and rapid analysis of the OmniLog™ PM data. PheMaDB allows the user to quickly identify records of interest for data analysis by filtering with a hierarchical ordering of Project, Strain, Phenotype, Replicate, and Temperature. PheMaDB then provides various statistical analysis options to identify specific growth pattern characteristics of the experimental strains, such as: outlier analysis, negative controls analysis (signal/background calibration), bar plots, pearson's correlation matrix, growth curve profile search, k-means clustering, and a heat map plot. This web-based database management system allows for both easy data sharing among multiple users and robust tools to phenotype organisms of interest. PheMaDB is an open source system standardized for OmniLog™ PM data. PheMaDB could facilitate the banking and sharing of phenotype data. The source code is available for download at http://phemadb.sourceforge.net .
A new responsive distributed shortest-path rounting algorithm

Distributed shortest-path routing algorithms based on the Ford-Fulkerson method are simple to implement but they suffer from the cost-dependent looping problem: when link costs increase, routing table loops may form and convergence to correct paths may be too slow, depending on link costs. This problem can be eliminated if constraints are imposed on the order in which routing tables are updated at different nodes but the resulting internode protocols tend to be relatively complex. Furthermore, update constraints may restrict a node's ability to obtain alternate paths quickly in an environment where topology changes are frequent. In this paper, a new distributed shortest-path routing scheme based on the Ford-Fulkerson method is presented. Under the new scheme, each node uses partial topology information to eliminate the cost-dependent looping problem. No update constraints are imposed and no assumptions are made regarding link costs. In the worst case, the new scheme responds to link cost changes in O(D) update steps, where D is the diameter of the network after the occurrence of the changes.
Repetition versus imagery instructions in the short- and long-term retention of paired-associates

Eighteen Ss learned three lists of 32 paired associates by the study-test method, Half of the items in each list were studied by repetition, and the other half by imagery. Imagery study resulted in better recall than did repetition study. Informing S at the time of test of the study method used for a given paired associate enhanced recall of items from List I, but did not influence recall on Lists 2 and 3. In addition, initial recall performance was poorer on List I than on the other lists, although List I items were better retained over a 1-week interval The results suggest that storage processes employed by S are dependent upon test experience.
Boundaries in the Drosophila wing imaginal disc organize vein-specific genetic programs

Previous studies have suggested that vein primordia in Drosophila form at boundaries along the A/P axis between discrete sectors of the larval wing imaginal disc. Genes involved in initiating vein development during the third larval instar are expressed either in narrow stripes corresponding to vein primordia or in broader ‘provein’ domains consisting of cells competent to become veins. In addition, genes specifying the alternative intervein cell fate are expressed in complementary intervein regions. The regulatory relationships between genes expressed in narrow vein primordia, in broad provein stripes and in interveins remains unknown, however. In this manuscript, we provide additional evidence for veins forming in narrow stripes at borders of A/P sectors. These experiments further suggest that narrow vein primordia produce secondary short-range signal(s), which activate expression of provein genes in a broad pattern in neighboring cells. We also show that crossregulatory interactions among genes expressed in veins, proveins and interveins contribute to establishing the vein-versus-intervein pattern, and that control of gene expression in vein and intervein regions must be considered on a stripe-by-stripe basis. Finally, we present evidence for a second set of vein-inducing boundaries lying between veins, which we refer to as paravein boundaries. We propose that veins develop at both vein and paravein boundaries in more ‘primitive’ insects, which have up to twice the number of veins present in Drosophila. We present a model in which different A/P boundaries organize vein-specific genetic programs to govern the development of individual veins.
Piezoelectric nanoribbons for monitoring cellular deformations

Methods for probing mechanical responses of mammalian cells to electrical excitations can improve our understanding of cellular physiology and function. The electrical response of neuronal cells to applied voltages has been studied in detail, but less is known about their mechanical response to electrical excitations. Studies using atomic force microscopes (AFMs) have shown that mammalian cells exhibit voltage-induced mechanical deflections at nanometre scales, but AFM measurements can be invasive and difficult to multiplex. Here we show that mechanical deformations of neuronal cells in response to electrical excitations can be measured using piezoelectric PbZr_xTi_(1-x)O_3 (PZT) nanoribbons, and we find that cells deflect by 1 nm when 120 mV is applied to the cell membrane. The measured cellular forces agree with a theoretical model in which depolarization caused by an applied voltage induces a change in membrane tension, which results in the cell altering its radius so that the pressure remains constant across the membrane. We also transfer arrays of PZT nanoribbons onto a silicone elastomer and measure mechanical deformations on a cow lung that mimics respiration. The PZT nanoribbons offer a minimally invasive and scalable platform for electromechanical biosensing.
Clinical relevance of increased retinoid and cAMP transcriptional programs in tumor cells rendered non-malignant by dominant negative inhibition of NFκB

Abstract We previously reported reciprocal regulation of extracellular matrix degrading enzymes and their endogenous inhibitors by NFκB. As such, dominant negative inhibition of NFκB in a murine lung alveolar carcinoma cell, Line 1, afforded a decrease in malignant proclivity [Cancer Res. 60(23) (2000) 6557–6562]. Contrasting the gene expression profile of malignant Line 1 tumor cells (WT-Line 1) and their non-malignant counterparts transduced with a dominant negative inhibitor of NFκB (mIκB-Line 1), we observed upregulated retinoic acid receptors (RARs) and the cAMP response element modulator (CREM), in mIκB-Line 1 tumor cells, and utilized heterologous promoter–reporter constructs to confirm enhanced responsiveness. We translate these findings by inducing retinoid and cAMP transcriptional programs in WT-Line 1 tumor cells with pharmacologic doses of all-trans retinoic acid (at-RA) and pentoxyfilline (PTX), respectively, and demonstrate suppression of NFκB activity, tumor cell derived matrix metalloprotease 9 activity, tumor cell invasiveness in vitro and spontaneous metastasis in vivo. Our results are consistent with the putative role of retinoids and cAMP in the malignant reversion of tumor cells and illustrative of the binary nature of transcriptional programs that modulate malignant progression.