cssi/SciSciGPT-SciSciNet huggingface dataset:
The progenitor state is maintained by lysine-specific demethylase 1-mediated epigenetic plasticity during Drosophila follicle cell development

Progenitors are early lineage cells that proliferate before the onset of terminal differentiation. Although widespread, the epigenetic mechanisms that control the progenitor state and the onset of differentiation remain elusive. By studying Drosophila ovarian follicle cell progenitors, we identified lysine-specific demethylase 1 (lsd1) and CoRest as differentiation regulators using a GAL4∷GFP variegation assay. The follicle cell progenitors in lsd1 or CoRest heterozygotes prematurely lose epigenetic plasticity, undergo the Notch-dependent mitotic-endocycle transition, and stop dividing before a normal number of follicle cells can be produced. Simultaneously reducing the dosage of the histone H3K4 methyltransferase Trithorax reverses these effects, suggesting that an Lsd1/CoRest complex times progenitor differentiation by controlling the stability of H3K4 methylation levels. Individual cells or small clones initially respond to Notch; hence, a critical level of epigenetic stabilization is acquired cell-autonomously and initiates differentiation by making progenitors responsive to pre-existing external signals.
Development of a Circulation Control Wing for UAVs

Circulation Control, which was discovered accidentally by Henry Coanda in 1935, is proven to be an efficient lift augmentation method at low Mach numbers. The objective of this research is to design and develop a Circulation Control Wing (CCW) that will provide increased lift to a fixed-wing Unmanned Aerial Vehicle (UAV). The configuration (the curvature of the trailing edge on a Clark-Y airfoil) that gives high lift augmentation ratios for reasonably low blowing rates is investigated. Wind tunnel tests are conducted on 11.7% thick circulation control airfoil with upper surface blowing capability. Different trailing edges (Coanda surfaces) have been tested at moment coefficients from 0.0 to 0.04. Test data are collected at Mach numbers of 0.021; 0.024; 0.029 and 0.030 at Reynolds numbers of 1.0 × 105 to 1.5 × 105. It is found that the smaller Coanda surface configuration is more effective. At M = 0.021 and α = 13°, the (2.1) Coanda surface gave the maximum ΔC L = 0.42 at a C µ = 0.04. The maximum lift enhancement (up to 155%) at zero angle-of-attack, is achieved by using the same Coanda surface(2.1) at C µ = 0.04 and M = 0.03.
Reactions of hypochlorite with catalase.

Abstract OCl−/HOCl imposed a rapid inactivation of catalase (hydrogen-peroxide: hydrogen-peroxide oxidoreductase, EC 1.11.1.6), some of which was slowly reversible upon subsequent exposure to H2O2. Ethanol accelerated this restoration of activity by H2O2. OCl− caused biphasic changes in the visible absorption spectrum of catalase, which were partially reversed by dithionite. A scheme of reactions involving axial ligation of one or two OCl− to heme iron, followed by heterolytic or homolytic cleavages of the OCl bond, is proposed to account for the behavior of the system.
The DataPath system: a data-centric analytic processing engine for large data warehouses

Since the 1970's, database systems have been "compute-centric". When a computation needs the data, it requests the data, and the data are pulled through the system. We believe that this is problematic for two reasons. First, requests for data naturally incur high latency as the data are pulled through the memory hierarchy, and second, it makes it difficult or impossible for multiple queries or operations that are interested in the same data to amortize the bandwidth and latency costs associated with their data access. In this paper, we describe a purely-push based, research prototype database system called DataPath. DataPath is "data-centric". In DataPath, queries do not request data. Instead, data are automatically pushed onto processors, where they are then processed by any interested computation. We show experimentally on a multi-terabyte benchmark that this basic design principle makes for a very lean and fast database system.
A macromolecular delivery vehicle for protein-based vaccines: Acid-degradable protein-loaded microgels

The development of protein-based vaccines remains a major challenge in the fields of immunology and drug delivery. Although numerous protein antigens have been identified that can generate immunity to infectious pathogens, the development of vaccines based on protein antigens has had limited success because of delivery issues. In this article, an acid-sensitive microgel material is synthesized for the development of protein-based vaccines. The chemical design of these microgels is such that they degrade under the mildly acidic conditions found in the phagosomes of antigen-presenting cells (APCs). The rapid cleavage of the microgels leads to phagosomal disruption through a colloid osmotic mechanism, releasing protein antigens into the APC cytoplasm for class I antigen presentation. Ovalbumin was encapsulated in microgel particles, 200–500 nm in diameter, prepared by inverse emulsion polymerization with a synthesized acid-degradable crosslinker. Ovalbumin is released from the acid-degradable microgels in a pH-dependent manner; for example, microgels containing ovalbumin release 80% of their encapsulated proteins after 5 h at pH 5.0, but release only 10% at pH 7.4. APCs that phagocytosed the acid-degradable microgels containing ovalbumin were capable of activating ovalbumin-specific cytoxic T lymphocytes. The acid-degradable microgels developed in this article should therefore find applications as delivery vehicles for vaccines targeted against viruses and tumors, where the activation of cytoxic T lymphocytes is required for the development of immunity.
AIDS in the Native Hawaiian Community

Native Hawaiians are at high risk for several health disorders and experience multiple socioeconomic problems. Infection rates for AIDS in this population are increasing and, when viewed in context of their overall poor health profile, are clearly indicators for concern. This article discusses the ramifications of AIDS in the native Hawaiian community by examining the knowledge and lifestyle practices of 26 native Hawaiians in Hawaii, and by identifying recommendations that may lead to the development of culturally responsive social services.
Experimental and theoretical study of the response of ZrO2 oxygen sensors to simple one-reducing-gas mixtures

Abstract The emf of commercial automotive zirconia oxygen sensors exposed to O 2 /CO/CO 2 /N 2 or O 2 /H 2 /H 2 O/N 2 gas mixtures was measured as a function of R ′=(2P O 2 /P CO ) or (2P O 2 /P H 2 ) at several temperatures. A step-like transition from high to low emf occurs at the switch-point R s0 ′ that is almost independent of temperature. The high emf (at say R ′=0.5) first increases and then decreases with temperature for O 2 /CO/CO 2 /N 2 gas mixture, whereas it only decreases for O 2 /H 2 /H 2 O/N 2 . These results may be analyzed using the steady state model of gas sensors [A.D. Brailsford, M. Yussouff, E.M. Logothetis, M. Shane, Steady-state model of a zirconia oxygen sensor in a simple gas mixture, Sensors and Actuators, B 24/25 (1995) 362–365]. Two lumped parameters, R s ′ and ξ , are needed in the model to compute the emf. R s ′ represents the theoretical switch-point and ξ determines the theoretical high emf. To obtain good fit with experiment, we choose R s ′ close to the observed R s0 ′ and then vary ξ . The quantity ξ depends upon the fundamental processes taking place on the sensor electrode; the temperature dependence of its fitted values (and hence the high emf) may be understood in terms of rate constants for adsorption, desorption and reaction.
Determination of molybdenum and tungsten in biological materials.

Abstract A spectrophotometric method for the quantitative determination of molybdenum and tungsten in the presence of each other in biological materials, has been developed. The method involves the selective formation and extraction of the complexes of the metals with 4-methyl-1,2-dimercaptobenzene under specified conditions of acidity and temperature. Possible interference by components found in biological materials, was examined and shown to be negligible.
Computer-aided design of chiral ligands. Part III. A novel ligand for asymmetric allylation designed using computational techniques.

Computer-aided design protocols to identify new chiral ligands for reactions proceeding through well-defined transition states are outlined. Ligand families are discovered via computational screeni...
Evaluating the Long-Term Impact of Professional Development.

The requirement in the USA of the No Child Left Behind Act (2002) that every classroom has a highly qualified teacher, coupled with the current high‐stakes testing environment, creates the need for all principals to be knowledgeable about quality staff development systems. One aspect of effective staff development is whether teachers adopt the principles, ideas and approaches presented. The purpose of this research was to examine the impact in terms of teacher use of professional development provided over a five‐year period at four individual campuses in a large urban school district.
Endovascular management of arteriovenous malformations of the brain

Arteriovenous malformations (AVMs) of the brain are rare, complex, vascular lesions that can result in significant morbidity and mortality. Modern treatment of brain AVMs is a multimodality endeavor, requiring a multidisciplinary team with expertise in cerebrovascular neurosurgery, endovascular intervention, and radiation therapy in order to provide all therapeutic options and determine the most appropriate treatment regimen depending on patient characteristics and AVM morphology. Current therapeutic options include microsurgical resection, radiosurgery (focused radiation), and endovascular embolization. Endovascular embolization is primarily used as a preoperative adjuvant before microsurgery or radiosurgery. Palliative embolization has been used successfully to reduce the risk of hemorrhage, alleviate clinical symptoms, and preserve or improve neurological function in inoperable or nonradiosurgical AVMs. Less frequently, embolization is used as ‘primary therapy’ particularly for smaller, surgically difficult lesions. Current embolic agents used to treat brain AVMs include both solid and liquid agents. Liquid agents including N-butyl cyanoacrylate and Onyx are the most commonly used agents. As newer embolic agents become available and as microcatheter technology improves, the role of endovascular treatment for brain AVMs will likely expand.
Patología mamaria en el niño

En la patologia infantil de la mama se relacionan varias entidades clinicas, algunas de las cuales solo son la expresion de variaciones fisiologicas. La glandula mamaria esta constituida por tres elementos: el tejido paleal, la glandula tubuloacinosa y la zona cutanea areolomamelonar. El desarrollo de estos distintos componentes se halla bajo dependencia hormonal y cada uno de ellos puede ser objeto, en diferentes periodos de la vida, de modificaciones que forman parte del ambito de las variaciones fisiologicas y que, casi siempre, solo requieren una simple vigilancia. Puede pensarse en otras lesiones mayoritariamente benignas en funcion de la edad de aparicion y del aspecto clinico, ecografico y evolutivo. Los autores discuten estas situaciones y recuerdan que, aunque los tumores malignos resultan excepcionales, a veces hay que pensar en ellos y practicar una biopsia.
Utilization of N,N-diethyl-3,5-difluorobenzene sulfonamide to prepare functionalized poly(arylene ether)s

Abstract A series of poly(arylene ether)s carrying a pendant diethyl sulfonamide group was prepared by the meta activated nucleophilic aromatic substitution reaction of a new aryl difluoride monomer, N , N -diethyl-3,5-difluorobenzene sulfonamide. The synthesis of N , N -diethyl-3,5-difluorobenzene sulfonamide was achieved via the one-step reaction of diethyl amine with commercially available 3,5-difluorobenzenesulfonyl chloride. Model reactions and NMR data indicated that the fluoride atoms were sufficiently activated by the sulfonamide group, located in the meta position, to provide access to high molecular weight poly(arylene ether)s. The corresponding poly(arylene ether)s, were prepared by reaction of N , N -diethyl-3,5-difluorobenzene sulfonamide with bisphenol A, bisphenol AF, 4,4′-biphenol, hydroquinone, resorcinol, and 4,4′-dihydroxydiphenyl ether. The polymers were characterized via NMR spectroscopy, size exclusion chromatography, thermogravimetric analysis, and differential scanning calorimetry. The sulfonamide based poly(arylene ether)s displayed moderate thermal stability with 5% weight loss temperatures ranging from 366 to 385 °C, but possessed relatively low glass transition temperatures, 72–142 °C.
Bank erodibility of shallow sandbed streams

Cross-sections were surveyed at straight reaches of 16 sandbed streams in the midwestern U.S. Two stratigraphic horizons are found in the banks at each site, an upper cohesive unit usually composed of silt and clay, and a lower unit composed of sand. Bank erosion on these rivers occurs when the upper cohesive unit is undercut by scour at bends. The overhanging cohesive block fails by toppling forward into the channel. During failure, the soil is primarily in tension rather than compression or shear. Analysis of this failure mechanism leads to a field method for measuring the tensile strength of riverbanks. Measured values of the tensile strength are not correlated with the channel geometry. Thus, the erodibility of the cohesive bank sediments does not influence the geometry of the rivers studied.
Anesthesia, XLIII. The estimation of anesthetic trifluoroethyl vinyl ether in aqueous solution.

The instantaneous reaction between trifluoroethyl vinyl ether and bromine water, resulting in a decolorization of the latter, has been adated for the colorimetric estimation of this ether in aqueous solution. Under suitaile conditions the degree of decolorization is roportional to the amount of the ether used. The method is simple and rapid and may be applicable to the examination of numerous other substances which are highly reactive toward bromine water in a similar manner.
Kinetics of materials with wiggly energies: Theory and application to the evolution of twinning microstructures in a Cu-Al-Ni shape memory alloy

We analyse the kinetics of the transition between two variants of martensite during biaxial dead loading. The volume fraction of one martensite variant versus the applied loads exhibits an unusual hysteresis, characterized by a sensitive dependence on the amplitude of the loads and a dissipationless response at small amplitude. Observation of the microscopic volume fraction at the level of a few bands of martensite reveals that the main mechanism by which one variant grows at the expense of another is a tip-splitting event; the tips of martensite needles present in the specimen suddenly split. This leads us to adopt a form of the energy in which many little wiggles are superposed on a slowly varying function that accounts for the loading device, elastic and interfacial energies. We analyse the resulting microscopic kinetic law by deriving from it a macroscopic kinetic equation that governs the average response. This law inherits the phenomenon of 'getting stuck in local minima of the energy'. It leads to good qualitative (and fair quantitative) agreement with observation over a very wide range of different kinds of experiment.
Processing hierarchy for 2-D image structures

Abstract The processing hierarchy for 2-D image structures based on geometric considerations is presented. The proposed pattern-recognition system is based on a structural approach that couples symbolic and numerical methods to manipulate symbolic descriptions, namely spatial occurrences of lines, arcs, circular regions, etc., each with values, properties and constrained relationships to other symbolic entities. The processing hierarchy includes hierarchical modeling and symbolic manipulation of 2-D image structures—aspects of the image-formation process. In this paper, a hybrid strategy for designing a character-recognition system is proposed that contains embedded coupled numerical and symbolic processing units and identified raw data and stored model's knowledge sources. Among the issues discussed is the process for evaluating image structures via computing dissimilarity levels (or variations) between feature descriptions of the prestored and extracted image structures. The variational concept has been implemented and the results are very encouraging.
Characterization of liver prenyl transferase and its inactivation by phenylglyoxal.

The two interconvertible forms of pig liver prenyl transferase, A and B, consist of two identical subunits of Mr = 38 500 and are dimers. Form A contains six titratable SH-groups, whereas form B contains only four per dimer. The amino acid composition of the two forms is otherwise identical. Both enzyme forms are inactivated by phenylglyoxal. The inactivation in the absence of Mg2+ or Mn2+ is biphasic, each phase following pseudo first-order kinetics and is accompanied by a proportional binding of [14C]phenylglyoxal to the protein. In the initial fast phase of inactivation (t12 = 9.6 min) the amount of [14C] phenylglyoxal bound to the enzyme extrapolated to 1.1 arginyl residues and in the second phase (t12 = 23 min) to 2.2 arginyl residues modified per subunit for complete inactivation. 1 mM Mg2+ and 0.1 mM Mn2+ abolished the initial fast rate of inactivation and reduced its rate to a single half-life of about 60 min. Even at this slow rate of inactivation in the presence of Mg2+, the amount of [14C] phenylglyoxal bound to the enzyme extrapolated to about 2.3 arginyl residues modified per subunit for complete inactivation. In the absence of Mg2+ or Mn2+ only 1 mM geranyl pyrophosphate protected the enzyme against inactivation. However, in the presence of 1 mM Mg2+, isopentenyl, dimethylallyl and geranyl pyrophosphates gave additional protection over that observed with the metal ions, geranyl pyrophosphate being the most effective at 0.1 mM concentration.
Hemochromatosis screening in asymptomatic ambulatory men 30 years of age and older

Objective To perform a cost-benefit analysis of screening for hereditary hemochromatosis. Patients and methods A total of 3,977 consecutive men ≥30 years of age who presented for routine health checkups at a health maintenance organization medical center were screened for hereditary hemochromatosis by measuring transferrin saturation. Subjects with repeated transferrin saturation ≥62% and ferritin level ≥500 ng/mL (≥500 μg/L) were referred for liver biopsy. Subjects wim transferrin saturation results Forty patients had transferrin saturation ≥62%. One hundred seventy-two had transferrin saturation 250 μmol/g dry weight. Two of them had hepatic fibrosis. Seven cases of hemochromatosis were found among 1,974 white subjects who were screened. Only 1 case was found among the remaining subjects. conclusions Our observations support routine screening with transferrin saturation for white men ≥30 years of age.
Microwave plasma torch — atmospheric-sampling glow discharge modulated tandem source for the sequential acquisition of molecular fragmentation and atomic mass spectra

A modulated tandem source consisting of a microwave plasma torch and an atmospheric-sampling glow discharge is investigated as a means of generating atomic and molecular mass spectra in a rapid, sequential manner. Conceptually, the pair operates by using the microwave plasma torch to produce atomic ions, and the atmospheric-sampling glow discharge for production of molecular fragmentation mass spectra. The mass spectra of several volatile organic compounds representative of both atomic and molecular modes of operation are presented, and the latter directly compared to mass spectra produced by an electron-impact ionization source. Unique aspects of the experimental construction and performance of this pair are considered.
A ROLE FOR NUCLEAR PHOSPHATIDYLINOSITOL-SPECIFIC PHOSPHOLIPASE C IN THE G2/M PHASE TRANSITION

Protein kinase C (PKC) is activated at the nucleus during the G2 phase of cell cycle, where it is required for mitosis. However, the mechanisms controlling cell cycle-dependent activation of nuclear PKC are not known. We now report that nuclear levels of the major physiologic PKC activator diacylglycerol (DAG) fluctuate during cell cycle. Specifically, nuclear DAG levels in G2/M phase cells are 2.5–3-fold higher than in G1 phase cells. In synchronized cells, nuclear DAG levels rise to a peak coincident with the G2/M phase transition and return to basal levels in G1 phase cells. This increase in DAG level is sufficient to stimulate βIIPKC-mediated phosphorylation of its mitotic nuclear envelope substrate lamin B in vitro. Isolated nuclei from G2 phase cells contain an active phospholipase activity capable of generating DAG in vitro. Nuclear phospholipase activity is inhibited by the selective phosphatidylinositol-specific phospholipase C (PI-PLC) inhibitor 1-O-octadeyl-2-O-methyl-sn-glycero-3-phosphocholine and neomycin sulfate, but not by the phosphatidylcholine-PLC selective inhibitor D609 or inhibitors of phospholipase D-mediated DAG generation. Treatment of synchronized cells with 1-O-octadeyl-2-O-methyl-sn-glycero-3-phosphocholine leads to decreased nuclear PI-PLC activity and cell cycle blockade in the G2 phase, suggesting a role for nuclear PI-PLC in the G2/M phase transition. Our data are consistent with the hypothesis that nuclear PI-PLC generates DAG to activate nuclear βII PKC, whose activity is required for mitosis.
Ubiquitination, Protein Turnover, and Long-Term Synaptic Plasticity

For at least half a century, alteration of synaptic strength through growth at specific nerve terminals has been favored as the mechanism underlying long-term changes in behavior and synaptic plasticity. Although new proteins for synapses can either be synthesized locally or transported from the cell body, recent work on the postsynaptic element (dendritic spines) of cortical excitatory synapses indicates that transmission can also be modified by controlling the density of alpha-amino-3-hydroxy-5-methylisoxazole-4-proprionic acid receptors (AMPARs) in the postsynaptic density (PSD). This regulation is mediated by mono-ubiquitination, which governs turnover of AMPAR subunits by determining whether the endocytosed subunits are sent to lysosomes to be degraded or recycled back to the membrane by exocytosis. Also important is activity-dependent multi-ubiquitination and degradation of proteins that make up the scaffolding complexes that confine receptors to the PSD.
Lack of effect of methylprednisolone on cardiac neural discharge associated with coronary occlusion-induced arrhythmia and death.

Abstract Methylprednisolone (30 or 50 mg/kg i.v.) was given 30 min prior to acute coronary occlusion of the left anterior descending artery. Neither dose of methylprednisolone exerted any effect on the mean postganglionic cardiac sympathetic nerve discharge prior to coronary occlusion and did not eliminate the nonuniform i.e., increased and/or decreased, neural discharge associated with occlusion-induced arrhythmia. Pretreatment with methylprednisolone did not increase the time to arrhythmia or death and did not decrease the number of cats dyring after acute coronary occlusion.
Spectroscopic Study of a Novel Bis(heptamethine cyanine) Dye and Its Interaction with Human Serum Albumin

A newly synthesized near-infrared (NIR) bis(heptamethine cyanine) dye 7 was evaluated for its utility as a non-covalent label for proteins. This dye forms inter- and intramolecular H-aggregates in polar solvents, even at very low concentrations. The intramolecular dimeric form of the dye can be described as a clam-shell complex with two interacting hydrophobic carbocyanine moieties. In this intramolecular H-aggregate, the chromophore has a low extinction coefficient and low fluorescence quantum yield. In aqueous solution, in the absence of human serum albumin (HSA), dye 7 has characteristic absorption bands at 792 and 435 nm, and its fluorescent emission is significantly diminished in comparison to that in methanol or when compared to its monomeric equivalent 5. Dye 7 seems to be more advantageous than its monomeric counterpart 5 as a non-covalent label for biomolecules. Upon addition of HSA, the H and D bands are decreased and the monomeric band is increased, with concomitant increase in fluorescence intensity, suggesting that clam-shell H-aggregates open up in the complex with HSA. The binding stoichiometry is 1:1. The main advantage of this dimeric dye as a non-covalent label is that the free dye has negligible fluorescence.
Zygotic development without functional mitotic centrosomes

The centrosome is the dominant microtubule-organizing center in animal cells. At the onset of mitosis, each cell normally has two centrosomes that lie on opposite sides of the nucleus. Centrosomes nucleate the growth of microtubules and orchestrate the efficient assembly of the mitotic spindle. Recent studies in vivo and in vitro have shown that the spindle can form even in the absence of centrosomes and demonstrate that individual cells can divide without this organelle. However, since centrosomes are involved in multiple processes in vivo, including polarized cell divisions, which are an essential developmental mechanism for producing differentiated cell types, it remains to be shown whether or not a complete organism can develop without centrosomes. Here we show that in Drosophila a centrosomin (cnn) null mutant, which fails to assemble fully functional mitotic centrosomes and has few or no detectable astral microtubules, can develop into an adult fly. These results challenge long-held assumptions that the centrosome and the astral microtubules emanating from it are essential for development and are required specifically for spindle orientation during asymmetric cell divisions.
Population growth and earth's human carrying capacity

Earth's capacity to support people is determined both by natural constraints and by human choices concerning economics, environment, culture (including values and politics), and demography. Human carrying capacity is therefore dynamic and uncertain. Human choice is not captured by ecological notions of carrying capacity that are appropriate for nonhuman populations. Simple mathematical models of the relation between human population growth and human carrying capacity can account for faster-than-exponential population growth followed by a slowing population growth rate, as observed in recent human history.
Diel periodicity in both sei whale vocalization rates and the vertical migration of their copepod prey observed from ocean gliders

The daily activity cycles of marine predators may be dictated in large part by the timing of prey availability. For example, recent studies have observed diel periodicity in baleen whale vocalization rates that are thought to be governed by the diel vertical migration of their zooplanktonic prey. We addressed this hypothesis by studying associations between sei whale (Balaenoptera borealis) vocalization rates, oceanographic conditions, and the vertical distribution of the whales' prey, the calanoid copepod Calanus finmarchicus, during May 2005 in the southwestern Gulf of Maine using an array of autonomous ocean gliders. Each of the four gliders was equipped with sensors to measure temperature, salinity, and chlorophyll fluorescence. Three of the four gliders carried a digital acoustic recorder and the fourth carried a 1 -MHz acoustic Doppler current profiler. We observed strong diel periodicity in the acoustic backscatter measured by the current profiler that we attribute (based on a corroborating shipboard study) to the diel vertical migration of C. finmarchicus. Sei whale vocalization rates also exhibited diel periodicity, with more calls detected during the daytime when C. finmarchicus was observed at depth. We found no evidence to suggest that the observed patterns in sei whale calling rates were attributable to diel periodicity in background noise or acoustic propagation conditions. Sei whales are adept at foraging on near-surface aggregations of C. finmarchicus; therefore we expect that the whales were feeding at night. We hypothesize that calling rates are reduced at night while the whales are feeding, but increase with social activity during the day when copepods are either more difficult or less efficient to capture at depth. The gliders' persistence during adverse weather conditions experienced during the study allowed continuous collocated observations of whale vocalization behavior and oceanographic conditions that have not been previously possible with traditional shipboard techniques.
Focusing on the Long-term: It's Good for Users and Business

Over the past 10+ years, online companies large and small have adopted widespread A/B testing as a robust data-based method for evaluating potential product improvements. In online experimentation, it is straightforward to measure the short-term effect, i.e., the impact observed during the experiment. However, the short-term effect is not always predictive of the long-term effect, i.e., the final impact once the product has fully launched and users have changed their behavior in response. Thus, the challenge is how to determine the long-term user impact while still being able to make decisions in a timely manner.We tackle that challenge in this paper by first developing experiment methodology for quantifying long-term user learning. We then apply this methodology to ads shown on Google search, more specifically, to determine and quantify the drivers of ads blindness and sightedness, the phenomenon of users changing their inherent propensity to click on or interact with ads.We use these results to create a model that uses metrics measurable in the short-term to predict the long-term. We learn that user satisfaction is paramount: ads blindness and sightedness are driven by the quality of previously viewed or clicked ads, as measured by both ad relevance and landing page quality. Focusing on user satisfaction both ensures happier users but also makes business sense, as our results illustrate. We describe two major applications of our findings: a conceptual change to our search ads auction that further increased the importance of ads quality, and a 50% reduction of the ad load on Google's mobile search interface.The results presented in this paper are generalizable in two major ways. First, the methodology may be used to quantify user learning effects and to evaluate online experiments in contexts other than ads. Second, the ads blindness/sighted-ness results indicate that a focus on user satisfaction could help to reduce the ad load on the internet at large with long-term neutral, or even positive, business impact.
Connecting atomistic and experimental estimates of ideal strength

The ideal strength is the minimum stress required to plastically deform an infinite defect-free crystal and is an upper bound to the strength of a real crystal. Disturbingly, however, the best available experimental estimates of the ideal strengths of tungsten and molybdenum are 25--50 % above the values predicted by recent ab initio density-functional calculations. This work resolves this discrepancy by extending the theoretical calculations to account for the triaxial state of stress seen in the nanoindentation experiments and by adjusting the experimental values to account for the crystallography of loading and the nonlinearity of the elastic response at large strains. Although an implicit assumption in many discussions of mechanical properties is that the ideal strength is not experimentally observable, as the true strength of most materials is limited by lattice defects, the close agreement between corrected experimental and theoretical estimates of ideal strength suggests that the ideal strength of some materials can be observed directly using nanoindentation.
Differential activation of proliferation and cytotoxicity in human T-cell lymphotropic virus type I Tax-specific CD8 T cells by an altered peptide ligand.

Abstract Human T-cell leukemia virus type I (HTLV-I) gives rise to a neurologic disease known as HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Although the pathogenesis of the disease is unknown, the presence of a remarkably high frequency of Tax-specific, cytotoxic CD8 T cells may suggest a role of these cells in the development of HAM/TSP. Antigen-mediated signaling in a CD8 T-cell clone specific for the Tax(11-19) peptide of HTLV-I was studied using analog peptides substituted in their T-cell receptor contact residues defined by x-ray crystallographic data of the Tax(11-19) peptide in the groove of HLA-A2. CD8 T-cell stimulation with the wild-type peptide antigen led to activation of p56lck kinase activity, interleukin 2 secretion, cytotoxicity, and clonal expansion. A Tax analog peptide with an alanine substitution of the T-cell receptor contact residue tyrosine-15 induced T-cell-mediated cytolysis without activation of interleukin 2 secretion or proliferation. Induction of p56lck kinase activity correlated with T-cell-mediated cytotoxicity, whereas interleukin 2 secretion correlated with [3H]thymidine incorporation and proliferation. Moreover, Tax peptide analogs that activated the tyrosine kinase activity of p56lck could induce unresponsiveness to secondary stimulation with the wild-type peptide. These observations show that a single amino acid substitution in a T-cell receptor contact residue of Tax can differentially signal CD8 T cells and further demonstrate that primary activation has functional consequences for the secondary response of at least some Tax-specific CD8 T cells to HTLV-I-infected target cells.
The Motion of Electrons in Nitrogen

Mobilities of electrons in nitrogen have been determined in fields ranging from 1 volt/cm to 55 volts/cm at atmospheric pressure. For low fields the mobility has a value of 18,000 cm/sec. but decreases rapidly for higher fields. The results agree for low fields with Compton's mobility equation, viz., $u=\frac{a}{{[1+{(1+B{x}^{2})}^{\frac{1}{2}}]}^{\frac{1}{2}}}$, but in order to obtain full agreement it must be assumed that the mean free path of the electron decreases as the velocity of the electron increases and also that the impacts of electrons with nitrogen molecules are not completely elastic. The mean free path of the electrons in nitrogen at a pressure of 760 mm and in thermal equilibrium with the molecules has been determined from the limiting mobility as the field in which the mobility is determined approaches zero. The value thus found is.000131 cm. This is about 2.7 times the kinetic theory value.
Construction by Molecular Dynamics Modeling and Simulations of the Porous Structures Formed by Dextran Polymer Chains Attached on the Surface of the Pores of a Base Matrix: Characterization of Porous Structures

Significant increases in the separation of bioactive molecules by using ion-exchange chromatography are realized by utilizing porous adsorbent particles in which the affinity group/ligand is linked to the base matrix of the porous particle via a polymeric extender. To study and understand the behavior of such systems, the M3B model is modified and used in molecular dynamics (MD) simulation studies to construct porous dextran layers on the surface of a base matrix, where the dextran polymer chains and the surface are covered by water. Two different porous polymer layers having 25 and 40 monomers per main polymer chain of dextran, respectively, are constructed, and their three-dimensional (3D) porous structures are characterized with respect to porosity, pore size distribution, and number of conducting pathways along the direction of net transport. It is found that the more desirable practical implications with respect to structural properties exhibited by the porous polymer layer having 40 monomers per main polymer chain, are mainly due to the higher flexibility of the polymer chains of this system, especially in the upper region of the porous structure. The characterization and analysis of the porous structures have suggested a useful definition for the physical meaning and implications of the pore connectivity of a real porous medium that is significantly different than the artificial physical meaning associated with the pore connectivity parameter employed in pore network models and whose physical limitations are discussed; furthermore, the methodology developed for the characterization of the three-dimensional structures of real porous media could be used to analyze the experimental data obtained from high-resolution noninvasive three-dimensional methods like high-resolution optical microscopy. The MD modeling and simulations methodology presented here could be used, considering that the type and size of affinity group/ligand as well as the size of the biomolecule to be adsorbed onto the affinity group/ligand are known, to construct different porous dextran layers by varying the length of the polymeric chain of dextran, the number of attachment points to the base matrix, the degree of side branching, and the number of main polymeric chains immobilized per unit surface area of base matrix. After the characterization of the porous structures of the different porous dextran layers is performed, then only a few promising structures would be selected for studying the immobilization of adsorption sites on the pore surfaces and the subsequent adsorption of the bioactive molecules onto the immobilized affinity groups/ligands.
The intramembrane location of alcohol anesthetics

In order to identify the chemical nature of the membrane receptor sites involved in general anesthesia the apparent free energy of binding of methylene groups of n-alcohols in anesthetic systems was evaluated and compared with data from model systems. It was concluded that the sites may consist either of (i) the non-polar portions of lipids, (ii) a non-polar region of a lipoprotein made up of non-polar portions of the protein and lipid moieties or (iii) protein. However, if the site consists only of protein it is possible that this material undergoes a ligand-induced conformation change on binding the anesthetic. Some reasons for the use of caution in employing temperature effects to identify the chemical nature of the receptor sites are outlined.
Theory and Applications of Network Error Correction Coding

Network error correction coding (NEC) has attracted a lot of attention in recent years because of its potential usefulness in network communications. Several kinds of errors may occur in communication networks using network coding. This includes random errors, erasures, and errors caused by attacks from malicious nodes. The main goal of the theory of NEC is to deal with these errors efficiently. Two kinds of network models have been considered in network coding theory: coherent and noncoherent networks. A network is called coherent if network characteristics are known to senders and receivers, and called noncoherent if they are unknown. Although both scenarios are theoretically interesting, the noncoherent network model fits better to the requirements in most applications. So far, there are two lines of research in the theory of NEC. One approach follows the classical method by representing messages by sequences and the other approach uses the theory of rank metric codes for network error correction by representing messages by subspaces. Following both approaches, basic theories have been developed. This includes the formulation of channel models, the characterization of error correction/detection capabilities for various kinds of errors, the derivation of bounds for NECs, the study of existence and constructions of optimal codes, the development of encoding and decoding techniques, and the design of code suitable for real applications. In this paper, we summarize some important contributions in this research direction.
Simultaneous comparison of two sound localization measures

Almost all behavioral studies of sound localization have used either an approach-to-target or pointing/orienting task to assess absolute sound localization performance, yet there are very few direct comparisons of these measures. In an approach-to-target task, the subject is trained to walk to a sound source from a fixed location. In an orienting task, finger, head and/or eye movements are monitored while the subject's body is typically constrained. The fact that subjects may also initiate head and eye movements toward the target during the approach-to-target task allows us to measure the accuracy of the initial orienting response and compare it with subsequent target selection. To perform this comparison, we trained cats to localize a broadband noise presented randomly from one of four speakers located ± 30° and ± 60° in azimuth. The cat responded to each sound presentation by walking to and pressing a lever at the perceived location, and a food reward was delivered if the first attempt was correct. In tandem, we recorded initial head and eye orienting movements, via magnetic search coils, immediately following target onset and prior to the walking response. Reducing either stimulus duration or level resulted in a systematic decline in both measurements of localization performance. When the task was easy, localization performance was accurate for both measures. When the task was more difficult, the number of incorrect (i.e., wrong selection) and no-go (i.e., no selection) responses increased. Interestingly, for many of the incorrect trials, there was a dissociation between the orienting response and the target selected, and for many of the no-go trials, the gaze oriented towards the correct target even though the cat did not move to it. This suggests different neural systems governing walking to a target as compared to unconditioned gaze orienting.
Expression of HGF, KGF, EGF and receptor messenger RNAs following corneal epithelial wounding.

Hepatocyte growth factor (HGF), keratinocyte growth factor (KGF), epidermal growth factor (EGF), and their receptors have been associated with homeostasis and wound healing in the cornea. The purpose of this study was to examine the expression of the messenger RNAs for these growth factors and receptors in a wounded series of mouse corneas using in situ hybridization. In situ hybridization was performed with 3H-labeled riboprobes on unwounded corneas and corneas at 30 minutes, 4, 12, 24, 48 and 72 hr, and 7 days after epithelial scrape wounds in Balb/C mice. Qualitative and semi-quantitative analyses were performed. Expression of HGF, KGF and EGF mRNAs in keratocytes in the unwounded cornea was low. EGF mRNA was also expressed in unwounded corneal epithelium. Following wounding, however, these growth factor mRNAs were markedly upregulated in keratocytes. EGF mRNA expression in the epithelium appeared unaffected by wounding. At seven days after wounding and several days following closure of the epithelial defect, HGF mRNA and KGF mRNA were still expressed at higher levels in keratocytes compared with unwounded corneas. No difference in expression of HGF or KGF mRNAs between limbal, peripheral corneal, or central corneal keratocytes was noted in the unwounded cornea, KGF receptor mRNA was prominently expressed throughout the unwounded corneal epithelium. HGF receptor mRNA and EGF receptor mRNAs were expressed at low levels in unwounded cornea epithelium. Following scrape injury, expression of HGF receptor mRNA and KGF receptor mRNA were markedly upregulated in the corneal epithelium, while no significant increase in EGF receptor mRNA expression was noted. These studies suggest a prominent role for HGF and KGF in modulating corneal epithelial wound healing following injury. Less prominent changes in EGF mRNA and EGF receptor mRNA in the corneal epithelium following wounding may suggest that EGF has more of a role in homeostasis in the mouse corneal epithelium.
Faculty publication productivity, collaboration, and grants velocity: using curricula vitae to compare center-affiliated and unaffiliated scientists

We examine the effect of a Congressionally mandated multidisciplinary center program on the careers of affiliated scientists. Important to the research evaluation design, we incorporate a control group of researchers who are not affiliated with these centers. We collect curricula vitae from both groups, a data source that has been demonstrated to provide valid and reliable longitudinal data about academic productivity. We evaluate the impact of center affiliation on publication productivity, collaboration, and grants activity. We find that center affiliation tends to promote lower grant velocity, but greater levels of collaboration. These higher levels of collaboration increase publication productivity, but gains may be offset by the lower grants velocity. Copyright , Beech Tree Publishing.
A Comparison Between National Healthcare Safety Network Laboratory-Identified Event Reporting versus Traditional Surveillance for Clostridium difficile Infection

OBJECTIVE Hospitals in the National Healthcare Safety Network began reporting laboratory-identified (LabID) Clostridium difficile infection (CDI) events in January 2013. Our study quantified the differences between the LabID and traditional surveillance methods. DESIGN Cohort study. SETTING A cohort of 29 community hospitals in the southeastern United States. METHODS A period of 6 months (January 1, 2013, to June 30, 2013) of prospectively collected data using both LabID and traditional surveillance definitions were analyzed. CDI events with mismatched surveillance categories between LabID and traditional definitions were identified and characterized further. Hospital-onset CDI (HO-CDI) rates for the entire cohort of hospitals were calculated using each method, then hospital-specific HO-CDI rates and standardized infection ratios (SIRs) were calculated. Hospital rankings based on each CDI surveillance measure were compared. RESULTS A total of 1,252 incident LabID CDI events were identified during 708,551 patient-days; 286 (23%) mismatched CDI events were detected. The overall HO-CDI rate was 6.0 vs 4.4 per 10,000 patient-days for LabID and traditional surveillance, respectively (P<.001); of 29 hospitals, 25 (86%) detected a higher CDI rate using LabID compared with the traditional method. Hospital rank in the cohort differed greatly between surveillance measures. A rank change of at least 5 places occurred in 9 of 28 hospitals (32%) between LabID and traditional CDI surveillance methods, and for SIR. CONCLUSIONS LabID surveillance resulted in a higher hospital-onset CDI incidence rate than did traditional surveillance. Hospital-specific rankings varied based on the HO-CDI surveillance measure used. A clear understanding of differences in CDI surveillance measures is important when interpreting national and local CDI data.