cssi/SciSciGPT-SciSciNet huggingface dataset:
Organization of vesicular trafficking in epithelia

Experiments using mammalian epithelial cell lines have elucidated biosynthetic and recycling pathways for apical and basolateral plasma-membrane proteins, and have identified components that guide apical and basolateral proteins along these pathways. These components include apical and basolateral sorting signals, adaptors for basolateral signals, and docking and fusion proteins for vesicular trafficking. Recent live-cell-imaging studies provide a real-time view of sorting processes in epithelial cells, including key roles for actin, microtubules and motors in the organization of post-Golgi trafficking.
Persistence in variable-yield nutrient-plankton models

Nutrient-phytoplankton-zooplankton models with general uptake functions in which only the internal nutrient concentration is capable of catalyzing cell growth and division for phytoplankton are proposed and analyzed. For the constant nutrient input model, it is shown that extinction or persistence of the population depends on its maximal growth rate relative to the total removal rate. The same biological conclusions hold for the periodic nutrient input model. However, while extinction and persistence are expressed in terms of convergence to steady states for the constant nutrient input model, these biological phenomena are exhibited in terms of asymptotic attraction to periodic solutions for the periodic nutrient input model.
Buffer sharing in video-on-demand servers

This paper describes a buffer sharing technique that strikes a balance between the use of disk bandwidth and memory in order to maximize the performance of a video-on-demand server. We make the key observation that the configuration parameters of the system should be independent of the physical characteristics of the data (e.g., popularity of a clip). Instead, the configuration parameters are fixed and our strategy adjusts itself dynamically at run-time to support a pattern of access to the video clips.
PHOTOCATALYTIC REACTIVITY OF THALLIUM (I) SPECIES IN AQUEOUS SUSPENSIONS OF TITANIA

Abstract The reactivity of Tl(I) species in UV-irradiated TiO2 suspensions is described. It is shown that the reaction pathway undergone by these species depends crucially on the conditions extant in these media. The Tl(I) conversion pathway switches from a reductive one in organic additive-containing suspensions to an oxidative one in the O2-containing media. Thus the influence of organic or inorganic co-additives, the purged gas (whether Ar or O2), and platinization of the TiO2 surface, on the extant of initial (dark) adsorption of Tl(I) on the TiO2 surface, and on the initial product of the photoreaction, is described.
Resonance coherent anti-Stokes Raman scattering (CARS) spectra of flavin adenine dinucleotide, riboflavin binding protein and glucose oxidase.

Abstract Coherent anti-Stokes Raman scattering spectra, in resonance with the isoalloxazine visible electronic transition, have been obtained down to 300 cm−1 for flavin adenine dinucleotide, riboflavin binding protein and glucose oxidase, in H2O and D2O. Several isoalloxazine vibrational modes can be identified by analogy with those of uracil. Of particular interest is a band at ∼1255 cm−1 in H2O, which is replaced by another at ∼1295 cm−1, in D2O. The H2O band appears to be a sensitive monitor of H-bonding of the N3 isoalloxazine proton to a protein acceptor group. It shifts down by 10 cm−1 in riboflavin binding protein, and disappears altogether in glucose oxidase. Other band shifts, of 3–5 cm−1, are similar for the two flavoproteins, and may reflect environmental changes between aqueous solution and the protein binding pockets.
Growth, microstructure, and strain relaxation in low‐temperature epitaxial Si1−xGex alloys deposited on Si(001) from hyperthermal beams

Epitaxial Si1−xGex(001) alloy films, with 0.15≤x≤0.30, were grown on Si(001) at temperatures Ts ranging from 300 to 550 °C using hyperthermal Si (average energy 〈ESi〉≂18 eV) and Ge (〈EGe〉≂15 eV) beams. The deposition rate was 0.1 nm s−1 and film thicknesses ranged from 30 nm to 0.8 μm. The energetic Si and Ge beams are generated by bombarding Si and Ge targets with 1 keV Kr+ ions from double‐grid, multiaperture, broad ion‐beam sources in a system geometry established based upon TRIM simulations of energy‐dependent angular distributions of sputtered and backscattered particles. A combination of high‐resolution plan‐view and cross‐sectional transmission electron microscopy, high‐resolution x‐ray diffraction, Rutherford backscattering spectroscopy, channeling, and axial angular‐yield profiles demonstrated that the films are of extremely high crystalline quality. Critical layer thicknesses hc for strain relaxation in these alloys were found to increase rapidly with decreasing growth temperature. For Si0.70Ge0...
Rheology of red blood cell aggregation by computer simulation

The aggregation of red blood cells (RBC) induced by the interactions between RBCs is a dominant factor of the in vitro rheological properties of blood, and existing models of blood do not contain full cellular information. In this work, we introduce a new three-dimensional model that couples Navier-Stokes equations with cell interactions to investigate RBC aggregation and its effect on blood rheology. It consists of a depletion mediated aggregation model to describe the interactions of RBCs and an immersed continuum model to track the deformation/motion of RBCs in blood plasma. To overcome the large deformation of RBCs, the meshfree method is used to model the RBCs. Three important phenomena in blood rheology are successfully captured and studied via this approach: the shear rate dependence of blood viscosity, the influence of cell rigidity on blood viscosity, and the Fahraeus-Lindqvist effect. As a microscopic illustration of the shear-rate dependence of the blood's viscoelasticity, the disaggregation of an RBC rouleau at shear rates varying between 0.125 and 24s^-^1 is modeled. Lower RBC deformability and higher shear rates above 0.5s^-^1 are found to facilitate disaggregation. The effective viscosities at different shear rates and for cells with different deformabilities are simulated. The numerical results are shown to agree with the reported experimental measurements. The Fahraeus-Lindqvist effect is, for the first time, studied through three-dimensional numerical simulations of blood flow through tubes with different diameters and is shown to be directly linked to axial-migration of deformable cells. This study shows that cell-cell interaction and cell deformability have significant effects on blood rheology in capillaries.
Differences in Adipose Tissue Metabolism between Postmenopausal and Perimenopausal Women

Changes in adipose tissue metabolism may contribute to the changes in body fat distribution seen during the menopause transition. We compared in vitro abdominal and gluteal sc adipose tissue metabolism [basal and stimulated lipolysis and activity of adipose tissue lipoprotein lipase (AT-LPL)] in postmenopausal and perimenopausal women (n = 12/group), matched for race, body mass index (29.5 +/- 3.8 kg/m(2); mean +/- SD), and percentage body fat (42 +/- 6%). The postmenopausal women were older (54 +/- 3 vs. 48 +/- 3 yr; P < 0.01) and had higher FSH (55.5 +/- 26.4 vs. 16.6 +/- 22.5 IU/ml; P < 0.01) and lower estradiol (33.8 +/- 14.9 vs. 97.4 +/- 61.7 pmol/liter; P < 0.05) concentrations than the perimenopausal women. Despite similar fat cell size and beta-adrenergic receptor and postreceptor (dibutyryl-cAMP)-stimulated lipolysis, basal lipolysis was 77% lower in gluteal adipose cells from postmenopausal compared with perimenopausal women (P < 0.05). Within each group, AT-LPL activity in the gluteal region was significantly higher than in the abdominal region (P < 0.05). In addition, AT-LPL activity was significantly higher in the postmenopausal compared with perimenopausal women in both gluteal (4.9 +/- 3.6 vs. 2.0 +/- 1.4 nmol free fatty acid/g.min; P < 0.05) and abdominal (3.2 +/- 2.6 vs. 1.3 +/- 0.9 nmol free fatty acid/g.min; P < 0.05) adipose cells. The results of this study suggest that menopause status is associated with differences in adipose tissue metabolism in both the abdominal and gluteal fat depots. The lower lipolysis and higher AT-LPL activity in postmenopausal women may predispose them to gain body fat after menopause.
Reaction of enargite (Cu3AsS4) in hot concentrated sulfuric acid under an inert atmosphere. Part I: Enargite concentrate

Abstract The sulfuric acid baking of an enargite concentrate was performed in a tube furnace under a flow of nitrogen gas. In this way the extent of reaction was measured in the absence of oxygen and a point of reference established. The effects of baking time, baking temperature, sulfuric acid dosage, and nitrogen flow rate on the water extraction of Cu, As, and Fe from the baked enargite concentrate were studied. Sulfuric acid baking of the concentrate for 3 h at 200 °C resulted in average Cu, As, and Fe extractions of ~ 75.7%, ~ 63.0%, and ~ 43.1%, respectively. The average As loss to the gas phase corresponding to the indicated operating conditions was ~ 5.9%. Characterization of the baked concentrate indicated the formation of S8, As2O3, HFe(SO4)2·4H2O, and Cu0.47Fe0.53SO4·H2O as a result of baking, identical to the phases formed upon sulfuric acid baking of the concentrate in a muffle furnace. The fact that no secondary copper sulfides were found to form around the enargite particles indicates that most probably enargite directly transformed to copper sulfate. The variation of temperature in the range 180–220 °C did not affect the extraction of Cu and Fe significantly, but As extraction decreased from ~ 65.2% to ~ 52.5%, owing to a systematic arsenic loss from ~ 3.7% at 190 °C to ~ 10.9% at 220 °C. Increasing the nitrogen flow rate from 340 mL/min to 1049 mL/min did not influence the extraction of Cu, As, and Fe upon water leaching. Sulfuric acid dosage had the greatest effect on the extraction of metals. Sulfuric acid to concentrate (S/C) weight ratios in the range 1.0–2.3 at a constant baking temperature of 200 °C over 6 h resulted in a steady increase of metals extraction from 52.6% to 82.2% for Cu, from 40.6% to 68.0% for As, and from 22.8% to 62.1% for Fe. No arsenic loss to the gas phase was observed when the highest S/C ratio (2.3) was used.
Formation of gas-phase negative ions in Fe(CO)5 and Ni(CO)4

Abstract The formation and structure of negative ions from iron and nickel carbonyl has been studied in gas-phase collision experiments using both low-energy (≦ 10 eV) electrons and fast (≦40 eV) potassium atoms as projectiles. Dissociative attachment of low-energy electrons to Fe(CO)5 and Ni(CO)4 occurs with a high probability to produce Fe(CO)4− and Ni(CO)3−, respectively. Structure is found in the dissociative attachment cross section for producing Fe(CO)3− and Fe(CO)2− from Fe(CO)5 in the energy region from 3 eV to 6 eV. This structure is attributed to predissociation from an electronically excited state of the Fe(CO)4− ion.
Children's health status: examining the associations among income poverty, material hardship, and parental factors.

Background We examined a model of multiple mediating pathways of income poverty, material hardship, parenting factors, and child health status to understand how material hardship and parental factors mediate the effects of poverty on child health. We hypothesized that: (a) poverty will be directly associated with material hardship, parental depression, and health status, and indirectly with parenting behaviors through its effects on parental depression and material hardship; (b) material hardship will be associated with parental depression, parenting behaviors, and health status; and (c) parental depression will be correlated with parenting behaviors, and that both parental depression and parenting behaviors will predict child health. Methods and results We used data from the 2002 National Survey of American Families for a sample of 9,645 6-to-11 year-olds to examine a 4-step structural equation model. The baseline model included covariates and income poverty. In the hardship model, food insufficiency and medical need were added to the baseline model. The parental model included parental depression and parenting behavior and baseline model. In the full model, all the constructs were included. First, income poverty had a direct effect on health status, and an indirect effect through its association with material hardship, parental depressive affect, and parenting behaviors. Medical need and food insufficiency had negative effects on child health, and indirect effects on health through their association with parental depression and parenting behaviors. Finally, parental depression and parenting behaviors were associated with child health, and part of the effect of parental depression on health was explained by its association with parenting behaviors. Conclusions Poverty has an independent effect on health, however, its effects are partially explained by material hardship, parental depression and parental behaviors. To improve children's health would require a multi-pronged approach involving income transfers, health insurance coverage, food and nutrition assistance, and parenting interventions.
Multimodal Sparsity-Eager Support Vector Machines for Music Classification

As the demand for multimedia grows, the development of information retrieval systems utilizing all available data modalities becomes of paramount importance. The provision of multiple modalities is motivated by usability, presence of noise in one modality and non-universality of a single modality. Radio stations and music TV channels hold archives of millions of music tapes and lyrics. Gigabytes of music files are also spread over the web along with the lyrics and metadata for each file. Searching and organizing large scale multimodal datasets is a challenging task. Supervised methods such as support vector machine (SVM) achieve state of the art performance for music classification on single modality, but suffer from over-fitting on training examples and limitations of single modality approaches. In this paper, we introduce a classifier fusion of multimodal audio and lyrics data to address these single modality classification limitations. We introduce the multimodal l1-SVM classifier, that utilizes sparse methods to deal with over-fitting for music classification. We compare the classification accuracy of the fusion classifier for a genre classification task in a large public dataset with single modality l1-SVM.
Dipole surface and infrared intensities for the cis- and trans-HOCO and DOCO radicals.

The vibrational spectra for the HOCO radical in both of its conformers and deuterated isotopologues are shown here for the first time. Building on previous work with coupled cluster quartic force fields (QFFs) in the computation of the fundamental vibrational frequencies for both cis- and trans-HOCO, coupled cluster dipole surfaces are now provided for both HOCO conformers and their corresponding deuterated isotopologues. These surfaces and subsequent vibrational configuration interaction (VCI) computations produce the intensities of transitions into vibrational states including the fundamentals, overtones, and first few combination bands of less than 4000 cm–1, slightly beyond the O–H stretch. Simulated spectra with an artificial full width at half-maximum broadening of 10 cm–1 are also provided in order to aid in the characterization of HOCO’s vibrational frequencies and to assist detection in various laboratory or astronomical observations.
The effects of anesthesia on the excretion of an isotonic saline load in the rat.

The ability to excrete a volume of isotonic saline equal to 10% of body weight infused over 60 min, was examined in awake rats and in rats anesthetized with 1 of the 2 agents most commonly used in renal clearance studies, Inactin or Nembutal. Rats anesthetized with Inactin excreted significantly less of the infused sodium during the period of infusion and in the 120-min post-infusion periods as compared to Nembutal-anesthetized rats or awake rats. Following saline infusion, there was a significantly greater decrease in serum protein concentration (25.5±4.7%) in rats anesthetized with Inactin, compared to that observed in the awake or Nembutal-treated rats. In a separate group of saline-infused awake rats, induction of anesthesia with Inactin resulted in a significant increase in hematocrit and a decrease in serum protein concentration. These studies suggest that Inactin anesthesia decreases the ability of the kidney to excrete a saline load and that, in studies of sodium excretion in the rat, especially if volume expansion is to be part of the experimental protocol, Nembutal rather than Inactin may be the anesthetic of choice.
Theory and modeling of electrically tunable metamaterial devices using inter-subband transitions in semiconductor quantum wells

In this paper, we propose a new and versatile mechanism for electrical tuning of planar metamaterials: strong coupling of metamaterial resonances to engineered intersubband transitions that can be tuned through the application of an electrical bias. We present the general formalism that allows calculating the permittivity tensor for intersubband transitions in generic semiconductor heterostructures and we study numerically the specific case of coupling and tuning metamaterials in the thermal infrared through coupling to biased GaAs semiconductor quantum wells. This tuning mechanism can be scaled from the visible to the far infrared by the proper choice of metamaterials and semiconductor heterostructures.
Comparison of an indirect immunofluorescence assay and a modified sensitive immunoblot assay for the study of the autoantibody in pemphigus vulgaris

Some patients with pemphigus vulgaris (PV) have positive direct immunofluorescence (DIF) but are negative by indirect immunofluorescence (IIF). The purpose of this study was (1) to compare the sensitivity of an IIF assay with an immunoblot (IB) assay, (2) to compare the IIF and the IB assay in PV patients in whom the clinical picture and DIF were consistent, but the IIF was negative and (3) to compare the IIF and the IB assay in patients in clinical remission for 3 years or more. A comparison was made of the titers of PV autoantibody in the IIF assay using monkey esophagus as substrate and the modified sensitive IB assay using preabsorbed normal human skin lysate and COLO-16 lysate as a substrate in the three groups of patients. The sensitivity of the Western blot was enhanced by modifications in the extraction procedure of the lysate, by absorption of lysate with normal human serum and by the use of an enzygraphic web. In group 1, comprising 23 PV patients with active generalized disease, the titers of the autoantibody in the IB assay were 2–4-fold higher than in the IIF assay. This difference was highly significant (P=0.0001). In group 2, comprising 10 patients with limited or minimal PV who were positive on DIF and negative on IIF, all the patients were positive in the IB assay. In group 3, comprising 9 patients clinically free of disease and off all therapy for at least 3 years and negative in IIF assay, all the patients were positive in the IB assay. An additional two such patients who had low titers in the IIF assay had significantly higher titers in the IB assay. In the IB assay normal human skin and COLO-16 cell lines produced similar results even though PV sera bound to a 130 kDa protein on normal human skin lysate and a 105 kDa protein on COLO-16 lysate. The availability of this modified sensitive IB assay will have significant clinical benefit in the diagnosis of PV patients when IIF is negative, and in the study of autoantibody production.
Pulmonary vein contraction: characterization of dynamic changes in pulmonary vein morphology using multiphase multislice computed tomography scanning.

Background The presence and extent of contraction within the pulmonary veins (PVs) have not been defined clearly. Objective The purpose of this study was to determine whether PV contraction exists and can be visualized using multislice computed tomography (MSCT) scanning as this may indicate that this modality may be useful for monitoring patients after PV isolation procedures. Methods Analysis was performed on 29 patients (mean age 57.5 ± 12 years) undergoing MSCT for suspected coronary artery disease without structural heart disease or left atrial anatomical variants. Multiplane reconstructions were used to measure PV diameters at 0, 5, 10, and 15 mm from the ostium in two phases (maximum and minimum size). The ejection fractions of three 5-mm segments were calculated for each PV. Results Right-sided and left-sided PV contraction and maximal atrial contraction occurred at a median of 85% and 95% of the cardiac cycle, respectively. The temporal concordance of minimal PV volume during peak atrial contraction indicated that the PV volume changes are secondary to active contraction rather than passive reflux and PV distension. The ejection fractions were highest in the superior veins: right superior PV (36.7%, 27.8%, and 16%, respectively, for the three segments from proximal to distal) and left superior PV (26.9%, 21.3%, and 12.1%), in comparison with the right inferior PV (21.1%, 6.6%, and −0.7%) and left inferior PV (15%, 9.3%, and 7.6%). Conclusion Volume changes related to active PV contraction occur extending up to 15 mm into the veins, and this effect is most pronounced in the superior veins.
A conceptual framework for evaluating and quantifying naturalness

: Naturalness is a scientific concept that can be evaluated and quantified Intactness or integrity of ecosystems can be defined and assessed in similar ways. Three indices of naturalness are proposed: (1) the degree to which the system would change if humans were removed; (2) the amount of cultural energy required to maintain the functioning of the system as it currently exists; and (3) the complement of native species currently in an area compared with the suite of species in the area prior to settlement. These indices are complementary and provide a conceptual framework for evaluating naturalness. The latter two can be quantified. Resumen: Lo silvestre (la naturalidad) es un concepto cientifico que puede ser evaluado y cuantificado. La virginidad e integridad de los ecosistemas puede ser definida y evaluada de manera similar. Se proponen tres indices de naturalidad. (1) el gradon en el que el sistema cambiaria si se removiera a los seres humanos; (2) la cantidad de energyia cultural requerida para mantener el funcionamiento del sistema en la forma en que existe actuulmente; y (3) el complemento de las especies nativas que se encuentran actualmente en un area, comparado con el grupo de especies en el area antes de los asentarnientos humanos. Estos indices son complementarios y ofrecen un marco de referencia conceptualpara evaluar la naturalidad Los dos ultimos pueden ser cuantificados.
Surveillance of patients with Barrett's esophagus for dysplasia and cancer with balloon cytology

Abstract BACKGROUND & AIMS: A less costly cancer surveillance method for Barrett's esophagus is desirable. The aim of this study was to compare nonendoscopic balloon cytology with biopsy and brush cytology for detecting dysplasia and carcinoma in patients with Barrett's esophagus. METHODS: Patients in a surveillance program underwent balloon cytology before endoscopy with biopsy and brush cytology. Results of cytology were compared with those of histology. RESULTS: Adequate columnar epithelium was obtained in 52 of 63 (83%) patients with balloon cytology and 59 of 61 (97%) with brush cytology. Balloon cytology obtained abnormal cells in 6 of 8 patients with adenocarcinoma, 2 of 2 patients with high-grade dysplasia, and 2 of 8 patients with low-grade dysplasia. Sensitivity of balloon cytology for high-grade dysplasia or carcinoma was 80% but only 25% for low-grade dysplasia. No patients without dysplasia or carcinoma had abnormal cells. Brush cytology was abnormal in all 11 patients with high-grade dysplasia or carcinoma but only 2 of 9 patients with low-grade dysplasia (sensitivity, 22%). Two of 39 patients without dysplasia had abnormal cells (specificity, 95%). Balloon cytology cost was sixfold less than endoscopy with biopsy. CONCLUSIONS: Balloon cytology detected 80% of patients with high-grade dysplasia or carcinoma when sampling was adequate. Brush cytology data suggest that a more abrasive balloon may improve balloon cytology sensitivity. The potential cost savings of balloon cytology compared with endoscopic cancer surveillance in Barrett's esophagus support further studies of this technique. (Gastroenterology 1997 Jun;112(6):1787-97)
Activation Analysis in Textile Processing

The use of neutron activation analysis as an analytical tool in textile processing is discussed. Gamma-ray spectra of activated fibers show the presence of many trace elements, but are not distinctive enough individually to allow identification of the fibers by the spectra. It is demonstrated that elements that lend themselves to neutron activa tion may be used as tracers in fiber process studies. Activation analysis may also be used successfully as a method for the analysis of yarns and fabrics for additives, such as sizes and finishes.
Epitaxially grown semiconductor surfaces

The atomic distributions on surfaces of Si, GaAs, HgTe and CdTe are studied as functions of temperature and substrate orientation in the [100], [111] and [111] directions. Surface entropy is calculated within the quasichemical approximation and the pair interaction energies are obtained using the tight-binding Green's function method. In most cases considered, the interactions between the atoms are attractive and they tend to congregate into islands for submonolayer coverage at temperatures below the roughening transition temperatures. Free energy curves for double-layer growth are presented. We find that growth in this case is mostly layer by layer as is often observed in atomic layer or molecular epitaxial growth. However, in cases such as Ga terminated [111] GaAs surfaces and most CdTe surfaces, the in-plane interactions are predicted to be repulsive. The calculated order-disorder transition temperatures for these cases are often much larger than usual growth temperatures and, consequently, incompletely filled surfaces are temperatures for these cases are often much larger than usual growth temperatures and, consequently, incompletely filled surfaces are expected to have domains in which atoms and vacancies arrange themselves in superlattice patterns.
Texture evolution in two-phase Zr/Nb lamellar composites during accumulative roll bonding

Abstract We study the texture evolution and deformation mechanisms in a Zr/Nb layered composite using a combination of electron backscattered diffraction, dislocation density evolution modeling, and polycrystal plasticity simulations. Zr/Nb composites with individual layer thicknesses ranging from 1 to 4 mm one-millimeter to four-micrometers were successfully fabricated at room temperature by accumulative roll bonding. Measured texture data during rolling and stress–strain curves in compression are presented. Under severe plastic deformation, we show that the textures of each polycrystalline phase correspond to textures of severely rolled single-phase rolled Zr and Nb. A visco-plastic self-consistent (VPSC)-dislocation density based model is applied to predict the deformation textures in the individual phases. The model indicates that large-strain deformation in Zr is accommodated by prismatic, pyramidal, and anomalously basal slip, and in Nb by both { 1 1 0 } and { 1 1 2 } slip. Our findings suggest that the polycrystalline layers of four micrometers per phase are still too coarse for the bimetal interfaces to have an effect on the texture evolution.
In vitro synthesis of T4 bacteriophage head protein using polysomes of T4-infected Escherichia coli.

Abstract Polyribosomes were prepared from Escherichia coli B cells infected with T4 bacteriophage virus and various mutant strains. A shift of the polysome distribution peak from 200 to 250 s early in the infection to 280 s late in the infection was observed for T4 infection. The virus amB17 is an amber T4 mutant which does not synthesize the bacteriophage head protein. Mutant amB17 -infected E. coli does not have 280 s polysomes. However, when an amber suppressor was introduced into the cell, head protein was synthesized and the 280 s polysome appeared. This suggested that the 280 s polysomes might be active in the synthesis of head protein. Tryptic digestion of the nascent polypeptide chains in the 280 s polysome yielded a pattern similar to that obtained from coat protein. The proteins made by T4- and amB17 -infected E. coli in vivo and those synthesized in an in vitro system were analyzed by acrylamide gel electrophoresis. The analysis showed that one of the proteins synthesized in vitro from the 280 s T4 polysomes had electrophoretic properties identical to the head protein. Several other proteins are also synthesized in vitro by the 280 s polysomes of T4-infected E. coli . Another T4 mutant, amN122 , does not make any late-function proteins, and E. coli infected with this virus contains no polysomes. Most of its ribosomes are found as ribosomal subunits.
Effects of nonlinear energy transfer on short surface waves

[1] The effects of nonlinear energy transfer on the development of the short wave spectrum are evaluated using a diffusion approximation and a modification of this approximation to include nonlocal effects. Both formulations were used to compute the evolution of a JONSWAP-type spectrum, and the results are compared with direct numerical simulations. Terms corresponding to each of these formulations were then incorporated into the wave action equation, and the resulting equation was numerically integrated using a second-order Runge-Kutta method. The results show an increase in the angular width of the spectrum and in the spectral density at high wave numbers as compared with solutions of the action equation without the nonlinear energy transfer term. Example results are presented for the case of a moderately strong internal wave in a light wind, and implications for the remote sensing of these waves using microwave radar are discussed.
The Science and Politics of Global Climate Change : A Guide to the Debate

This third edition has been comprehensively updated to reflect the large changes in scientific knowledge and policy debates on climate change since the previous edition in 2009. It provides a concise but thorough overview of the science, technology, economics, policy, and politics of climate change in a single volume. It explains how scientific and policy debates work, outlines the scientific evidence for the reality and seriousness of climate change and the basic atmospheric science that supports it, and discusses policy options and the current state of the policy debate. By pulling these elements together, the book explains why the issue can be so confusing and provides guidance on practical routes forward. Anyone interested in climate change, the global environment, or how science is used in policy debates should read this book. It is the ideal textbook for undergraduate or graduate courses in environmental policy and climate change.
Universal negative differential resistance in one-dimensional resistors

A novel universal (material-independent) negative differential resistance is shown to exist in strictly one-dimensional systems (quantum wires) as a consequence of energy and momentum conservation in the interaction of one-dimensional confined carriers with one-dimensional confined acoustic phonons. The average (steady state) carrier energy should also exhibit a non-monotonic dependence on the driving electric field. Candidate systems to exhibit this negative differential resistance are suspended semiconductor nanobridges and semiconducting carbon nanotubes.
The Effects of Influenza A Virus PB1-F2 Protein on Polymerase Activity Are Strain Specific and Do Not Impact Pathogenesis

The influenza A virus PB1-F2 protein has been implicated as a virulence factor, but the mechanism by which it enhances pathogenicity is not understood. The PB1 gene segment of the H1N1 swine-origin influenza virus pandemic strain codes for a truncated PB1-F2 protein which terminates after 11 amino acids but could acquire the full-length form by mutation or reassortment. It is therefore important to understand the function and impact of this protein. We systematically assessed the effect that PB1-F2 expression has on viral polymerase activity, accumulation and localization of PB1, and replication in vitro and in mice. We used both the laboratory strain PR8 and a set of viruses engineered to study clinically relevant PB1-F2 proteins. PB1-F2 expression had modest effects on polymerase activity, PB1 accumulation, and replication that were cell type and virus strain dependent. Disruption of the PB1-F2 reading frame in a recent, seasonal H3N2 influenza virus strain did not affect these parameters, suggesting that this is not a universal function of the protein. Disruption of PB1-F2 expression in several backgrounds or expression of PB1-F2 from the 1918 pandemic strain or a 1956 H1N1 strain had no effect on viral lung loads in mice. Alternate mechanisms besides alterations to replication are likely responsible for the enhanced virulence in mammalian hosts attributed to PB1-F2 in previous studies.
Contributions of visual and embodied expertise to body perception.

Recent research has demonstrated that our perception of the human body differs from that of inanimate objects. This study investigated whether the visual perception of the human body differs from that of other animate bodies and, if so, whether that difference could be attributed to visual experience and/or embodied experience. To dissociate differential effects of these two types of expertise, inversion effects (recognition of inverted stimuli is slower and less accurate than recognition of upright stimuli) were compared for two types of bodies in postures that varied in typicality: humans in human postures (human-typical), humans in dog postures (human-atypical), dogs in dog postures (dog-typical), and dogs in human postures (dog-atypical). Inversion disrupts global configural processing. Relative changes in the size and presence of inversion effects reflect changes in visual processing. Both visual and embodiment expertise predict larger inversion effects for human over dog postures because we see huma...
ONE APPROACH TO REALLOCATING INSTRUCTIONAL RESOURCES: THE HOUSTON MODEL

In this paper a model for deciding which instructional departments should receive and surrender new or reallocatable resources is developed. It combines a two-dimensional assessment of resource needs based on instructional characteristics and the academic priority of the department to arrive at resource allocation priorities. Unusual features of the model are its reliance on judgments of departmental centrality to institutional mission as the discriminating variable in ascribing academic priorities and the careful avoidance of “halo effects” through independent assessment of resource needs and academic priorities. The model is sensitive enough to discriminate between competing claims for scarce resources while retaining a simplicity of logic that makes its mechanics understandable to those with little grounding in the decision sciences.
From simple technology to complex arena: classification of Pap smears, 1917-90.

This article explores historical constructions of Pap smear classification systems from 1917 to 1990. Using a social worlds/arenas analysis, we examine the perspectives and properties of all the major actors (both human and nonhuman) in the Pap smear arena, including implicated actors. Analytical emphasis is on interpretive struggles among different actors in this arena and centers on the consequences of such conflicts for global classificatory systems and on the global classificatory criteria. We describe some of the local clinical “work-arounds” designed to resolve problems of classification standards in practice. In drawing theoretical conclusions, comparison is made between Pap smear classification systems and two other systems.
Intramolecular hydrogen atom abstraction in carbohydrates and nucleosides : inversion of an α- to β-mannopyranoside and generation of thymidine C-4' radicals

Abstract Treatment of 1-bromo-2-methyl-2-propyl ether derivatives of alcohols with Bu 3 SnH(D) results in 1,5-Hydrogen abstraction reactions: the system is applied to the inversion of an α- to β-mannoside and to the formation of nucleoside C4′ radicals.
Plasminogen Activator Inhibitor-1 Polymorphism (4G/5G) Predicts Recurrence in Nonhyperlipidemic Postinfarction Patients

Objective— Nonhyperlipidemic postinfarction patients are at high risk for recurrent coronary events by virtue of incident myocardial infarction (MI); however, few studies assess risk beyond incident MI. The aim of this study was to assess such risk as a function of 37 atherosclerosis-associated genetic polymorphisms and 17 blood marker variables. Methods and Results— Screening of polymorphisms in nonhyperlipidemic postinfarction patients revealed significant risk only for the 4G/5G insertion/deletion polymorphism in the promoter of the plasminogen-activator inhibitor-1 (PAI-1) gene. Outcome event mapping, an exploratory data analysis tool, was then applied to define a subgroup (182 patients from total study population of 846 nondiabetic patients) exhibiting maximal functional dependence of risk on the PAI-1 polymorphism. Cox multivariable regression analyses within the subgroup adjusted for significant clinical covariates and medication use as a function of the PAI-1 polymorphism and 17 atherosclerosis-associated blood markers revealed significant risk for patients homozygous for the 4G allele (hazard ratio 4.30, 95% CI 1.98 to 9.33, P =0.00023), and lack of significant risk-association with any blood marker. Conclusions— In a subgroup of normolipidemic postinfarction patients, only the PAI-1 4G/5G polymorphism was associated with recurrent risk from a set of atherosclerosis-associated genetic polymorphisms and blood markers.
The bifurcation of homoclinic orbits of maps of the interval

Relationships involving homoclinic orbits of various periods and the Sarkovskii stratification are given and corresponding bifurcation properties are derived. It is shown that if a continuous map has one homoclinic periodic orbit, it has infinitely many. In any family of C 1 maps going from zero to positive entropy, infinitely many homoclinic bifurcations occur, involving periods which are successively smaller powers of two.
Melanges in the Franciscan Complex, a product of triple-junction tectonics

Tectonism near Cape Mendocino is ascribed to the north-northwestward migration of the Mendocino triple junction; it is characterized as a process in which the wedge of continental plate left in the wake of the retreating subducted extension of the Juan de Fuca plate is pushed and folded back by the advancing corner of the Pacific plate. Between Late Jurassic and Paleocene time, a different type of triple junction in which the oceanic plate and its obliquely subducting continuation advanced rather than retreated, herein named the Humboldt type, transited the western side of the continental plate. The laterally advancing subducted extension of the oceanic plate uplifted and snowplowed aside the continental plate, resulting in up-heaval, disruption, and gravity sliding of deep elements of the crust, including blueschist. The melange of the Franciscan Complex is a product of successive transits of Humboldt- and Mendocino-type triple junctions along the western edge of the continental plate.
On Sunk Costs and Escalation

The sunk cost effect is demonstrated when a past investment of time, money, or effort increases the likelihood of further investment. Escalation is the tendency to continue investment despite negative consequences. Although some researchers have defined the sunk cost effect as a subset of escalation, others use the terms interchangeably and only examine one of the two phenomena. In order to further clarify the relation between escalation and the sunk cost effect, the current study used a novel experimental analog wherein participants made an initial forced investment ($5, $20, $35; randomized) before choosing to pay to complete the project ($5, $20, $50, $80, $95; randomized), or to begin a new project (free). There was a systematic positive relation between initial investment price and the proportion of choices to complete the project at the highest terminal investment ($95) for those who committed the sunk cost effect. Moreover, 54 % of participants exhibited an overall sunk cost effect whereas 87 % of participants completed projects even when the additional investment was higher than the expected average of completing a new trial (>$70), demonstrating escalation. These two effects were differentially impacted by the amount of the further investment, functionally differentiating the sunk cost effect from escalation.
Human sperm glutathione reductase activity in situ reveals limitation in the glutathione antioxidant defense system due to supply of NADPH

In order to characterize further the antilipoperoxidative enzyme system of human sperm, that part of the system designed to provide reducing equivalents for the reduction of highly reactive and potentially damaging lipid hydroperoxides to relatively inert hydroxylipids was examined. The substrate that provides the reducing equivalents directly to glutathione peroxidase (GPX) is reduced glutathione (GSH), which is in turn oxidized to glutathione disulfide (GSSG). The reducing equivalents needed for regeneration of GSH through the action of glutathione reductase (GRD) are provided by NADPH, produced by the action of glucose-6-phosphate dehydrogenase (G6P-DH) on substrates glucose-6-phosphate and NADP+. The kinetic properties of the enzymes GRD and G6P-DH were determined by standard enzyme activity assay at 24 and 37 degrees C. At 37 degrees C, the Vmax for GRD was found to be 36 nmol/min x 10(8) cells, with Km values for GSSG and NAPH of 150 microM and 16 microM, respectively; the Vmax for G6P-DH was 3.3 nmol/min x 10(8) cells with Km for NADP+ of 8 microM. This suggested that G6P-DH activity was limiting in this reductive pathway. The activity of GRD in situ in intact cells was estimated using the thiol-reactive fluorogenic probe ThioGlo-1, which is cell permeant and reacts rapidly with GSH to give a highly fluorescent adduct. Mixing a suspension of human sperm with the fluorogenic reagent at 37 degrees C gave an initial rapid increase in fluorescence, followed by a slower one. The rapid phase is due to reaction with intracellular GSH already present; the slow phase is due to reaction with GSH generated by the GRD-catalyzed reduction of GSSG. Both rates showed first-order kinetics. Calculation of the maximal rate as NADPH oxidation, attributable to in situ GRD activity, gave the value of 1.0 nmol/min x 10(8) cells, less than the maximum for NADPH production by the dehydrogenase. These results support the suggestion that NADPH production limits the capacity of the pathway leading to hydroperoxide reduction in human sperm. We propose that the antilipoperoxidative defense system of human sperm has just sufficient capacity to allow these cells to fulfill their function but is limited to allow their timely disposal from the female reproductive tract.
Bacterial succession in a petroleum land treatment unit.

Bacterial community dynamics were investigated in a land treatment unit (LTU) established at a site contaminated with highly weathered petroleum hydrocarbons in the C10 to C32 range. The treatment plot, 3,000 cubic yards of soil, was supplemented with nutrients and monitored weekly for total petroleum hydrocarbons (TPH), soil water content, nutrient levels, and aerobic heterotrophic bacterial counts. Weekly soil samples were analyzed with 16S rRNA gene terminal restriction fragment (TRF) analysis to monitor bacterial community structure and dynamics during bioremediation. TPH degradation was rapid during the first 3 weeks and slowed for the remainder of the 24-week project. A sharp increase in plate counts was reported during the first 3 weeks, indicating an increase in biomass associated with petroleum degradation. Principal components analysis of TRF patterns revealed a series of sample clusters describing bacterial succession during the study. The largest shifts in bacterial community structure began as the TPH degradation rate slowed and the bacterial cell counts decreased. For the purpose of analyzing bacterial dynamics, phylotypes were generated by associating TRFs from three enzyme digests with 16S rRNA gene clones. Two phylotypes associated with Flavobacterium and Pseudomonas were dominant in TRF patterns from samples during rapid TPH degradation. After the TPH degradation rate slowed, four other phylotypes gained dominance in the community while Flavobacterium and Pseudomonas phylotypes decreased in abundance. These data suggest that specific phylotypes of bacteria were associated with the different phases of petroleum degradation in the LTU.
Modeling decadal bed material sediment flux based on stochastic hydrology

Estimates of decadal bed material sediment flux and net storage are derived by driving sediment transport calculations with a stochastic hydrology model. The resulting estimates represent the whole distribution of sediment flux based on natural variability in channel characteristics (gradient, width, and bed grain size) and the magnitude, duration, and interarrival time of flood events. A procedure for calibrating a fractional sediment transport equation of a commonly used form to bed material grain size distributions (BMGSDs) at cross sections is presented. The procedure was applied to the Sacramento River channel network to compute estimates of annual total and annual peak bed material discharges into and through the main stem over a 30-year period. Main stem bed material budgets were evaluated to identify reaches in states of net accumulation or scour. Simulations highlight large imbalances in sand and gravel storage throughout the Sacramento River, which can be explained by a combination of local hydraulics and BMGSDs and for which there is at least some empirical support.
Automatic Discovery of Cognitive Skills to Improve the Prediction of Student Learning

To master a discipline such as algebra or physics, students must acquire a set of cognitive skills. Traditionally, educators and domain experts use intuition to determine what these skills are and then select practice exercises to hone a particular skill. We propose a technique that uses student performance data to automatically discover the skills needed in a discipline. The technique assigns a latent skill to each exercise such that a student's expected accuracy on a sequence of same-skill exercises improves monotonically with practice. Rather than discarding the skills identified by experts, our technique incorporates a nonparametric prior over the exercise-skill assignments that is based on the expert-provided skills and a weighted Chinese restaurant process. We test our technique on datasets from five different intelligent tutoring systems designed for students ranging in age from middle school through college. We obtain two surprising results. First, in three of the five datasets, the skills inferred by our technique support significantly improved predictions of student performance over the expert-provided skills. Second, the expert-provided skills have little value: our technique predicts student performance nearly as well when it ignores the domain expertise as when it attempts to leverage it. We discuss explanations for these surprising results and also the relationship of our skill-discovery technique to alternative approaches.