cssi/SciSciGPT-SciSciNet huggingface dataset:
All-optical high-speed analog-to-encoded-digital conversion of optically sampled signals

Analog-to-digital (AID) converters with sampling rate in the gigabits/sec are desirable in many advanced communication systems including RADAR, microwave and cable links1, and for designing zero intermediate frequency receivers, as well as in the implementation ofhigh-speed test and measurement equipment. Today's electronic AID converters have limiting speeds in the megahertz range, whereas most advanced communication systems operate in the gigahertz range. Optical devices and systems can operate at much higher speeds, and therefore there is great interest to design and implement all-optical A/D converters. Several optical AID converter schemes, intended to circumvent the electronic bottleneck have been proposed2 . Unfortunately, such schemes require complex circuitry for the sampler and/or the quantizer, and often require high-power. As a result these schemes are unsuitable for large-scale system that require low-power consumption, or for systems with many transmit/receive units such as in RADAR or satellite communication systems. We present the design and demonstration of an all-optical A/D converter whose attractive features include 1) direct optical sampling of the input RF signal, 2) optical quantization scheme, 3) utilization of optical signal multiplexing to provide parallel procession of quantized signals at electronic speed, and 4) low-power consumption.
Crystallization and preliminary X-ray diffraction analysis of the BRPF1 bromodomain in complex with its H2AK5ac and H4K12ac histone-peptide ligands.

The bromodomain-PHD finger protein 1 (BRPF1) is an essential subunit of the monocytic leukemia zinc (MOZ) histone acetyltransferase (HAT) complex and is required for complex formation and enzymatic activation. BRPF1 contains a structurally conserved bromodomain, which recognizes specific acetyllysine residues on histone proteins. The MOZ HAT plays a direct role in hematopoiesis, and deregulation of its activity is linked to the development of acute myeloid leukemia. However, the molecular mechanism of histone-ligand recognition by the BRPF1 bromodomain is currently unknown. The 117-amino-acid BRPF1 bromodomain was overexpressed in Escherichia coli and purified to homogeneity. Crystallization experiments of the BRPF1 bromodomain in complex with its H4K12ac and H2AK5ac histone ligands yielded crystals that were suitable for high-resolution X-ray diffraction analysis. The BRPF1 bromodomain–H4K12ac crystals belonged to the tetragonal space group P43212, with unit-cell parameters a = 75.1, b = 75.1, c = 86.3 A, and diffracted to a resolution of 1.94 A. The BRPF1 bromodomain–H2AK5ac crystals grew in the monoclinic space group P21, with unit-cell parameters a = 60.9, b = 55.6, c = 82.1 A, β = 93.6°, and diffracted to a resolution of 1.80 A. Complete data sets were collected from both crystal forms using synchrotron radiation on beamline X29 at Brookhaven National Laboratory (BNL).
Pharmacodynamics, Population Dynamics, and the Evolution of Persistence in Staphylococcus aureus

When growing populations of bacteria are confronted with bactericidal antibiotics, the vast majority of cells are killed, but subpopulations of genetically susceptible but phenotypically resistant bacteria survive. In accord with the prevailing view, these “persisters” are non- or slowly dividing cells randomly generated from the dominant population. Antibiotics enrich populations for pre-existing persisters but play no role in their generation. The results of recent studies with Escherichia coli suggest that at least one antibiotic, ciprofloxacin, can contribute to the generation of persisters. To more generally elucidate the role of antibiotics in the generation of and selection for persisters and the nature of persistence in general, we use mathematical models and experiments with Staphylococcus aureus (Newman) and the antibiotics ciprofloxacin, gentamicin, vancomycin, and oxacillin. Our results indicate that the level of persistence varies among these drugs and their concentrations, and there is considerable variation in this level among independent cultures and mixtures of independent cultures. A model that assumes that the rate of production of persisters is low and persisters grow slowly in the presence of antibiotics can account for these observations. As predicted by this model, pre-treatment with sub-MIC concentrations of antibiotics substantially increases the level of persistence to drugs other than those with which the population is pre-treated. Collectively, the results of this jointly theoretical and experimental study along with other observations support the hypothesis that persistence is the product of many different kinds of errors in cell replication that result in transient periods of non-replication and/or slowed metabolism by individual cells in growing populations. This Persistence as Stuff Happens (PaSH) hypothesis can account for the ubiquity of this phenomenon. Like mutation, persistence is inevitable rather than an evolved character. What evolved and have been identified are genes and processes that affect the frequency of persisters.
Alexander's disease: further light-, and electron-microscopic observations.

The neuropathologic and ophthalmopathologic findings in a 53/4-year-old boy with Alexander's disease are reported. Light- and electron-microscopic and immunohistochemical studies revealed that (1) the granular osmiophilic deposits (GOD) in Alexander's disease accumulate mainly in astrocytic processes to form Rosenthal fibers, (2) the Bergmann glia are different in this regard and accumulate the deposits primarily in their perikarya, (3) the Muller cells of retina (which closely resemble astrocytes) do not accumulate GOD, (4) the deposits are also not present in other glial cells and glial-like cells such as pituicytes and pineocytes, (5) the deposits are sparse in the retrobulbar optic nerves, and (6) the peroxidase-antiperoxidase and immunofluorescence studies did not demonstrate glial fibrillary acidic protein (GFAP), albumin, immunoglobulins, or fibrinogen in the astrocytic deposits. The differential deposition of GOD in various cytoplasmic regions of astrocytes in different areas of central nervous system (CNS) suggests that astrocyte metabolism may not be uniform throughout the brain. Attention to this point may prove helpful in understanding the pathogenesis of the deposits in Alexander's disease. The absence of immunohistochemically demonstrable plasma proteins and GFAP in the astrocytic GOD indicates that the latter have an origin different from plasma proteins and glial filaments. Alternatively, the deposits may be derived from these proteins, but their antigenicity has since been altered.
The technological gatekeeper: Evidence in three industries

Previous studies have developed the concept of the “technological gatekeeper” as one who is integral in the diffusion of scientific and technical information from the environment into the R&D firm. Gatekeepers have been found in firms operating in environments with rapidly changing technology. Using data from six firms in three industries, the present study found the gatekeeper phenomenon extends to firms with less rapidly changing environments. Thus, the gatekeeper construct becomes important to any firm with a R&D mission. Additionally, many of the sociometric and demographic characteristics of gatekeepers were validated in new research settings.
Shoot regeneration from hormone-autonomous callus from shoot cultures of several sugarbeet (Beta vulgaris L.) genotypes

Abstract Shoot cultures of six sugarbeet genotypes produced callus when grown in dim fluorescent light (10–15 μEm−2 s−1) at 30°C on Murashige-Skoog (MS) medium with 0.25 mg/l 6-benzyladenine (BA). Hormone autonomy of the callus was indicated by sustained callus growth following multiple transfers onto MS medium lacking auxin and cytokinin. Shoots were regenerated from 1-month-old callus of two genotypes after transfer to MS medium with 0.25–5.0 mg/l BA at 30°C in dim fluorescent light (10–15 μEm−2 s−1).
Predicting reduction rates of energetic nitroaromatic compounds using calculated one-electron reduction potentials.

The evaluation of new energetic nitroaromatic compounds (NACs) for use in green munitions formulations requires models that can predict their environmental fate. Previously invoked linear free energy relationships (LFER) relating the log of the rate constant for this reaction (log(k)) and one-electron reduction potentials for the NAC (E1NAC) normalized to 0.059 V have been re-evaluated and compared to a new analysis using a (nonlinear) free-energy relationship (FER) based on the Marcus theory of outer-sphere electron transfer. For most reductants, the results are inconsistent with simple rate limitation by an initial, outer-sphere electron transfer, suggesting that the linear correlation between log(k) and E1NAC is best regarded as an empirical model. This correlation was used to calibrate a new quantitative structure–activity relationship (QSAR) using previously reported values of log(k) for nonenergetic NAC reduction by Fe(II) porphyrin and newly reported values of E1NAC determined using density functio...
X-ray monochromator characteristics for a Coherent Energy Recovery Linac Source of Hard X-rays

Energy recovery linacs can produce highly coherent hard X-rays beams. Reflection from a silicon (111) crystal will not do much harm to an ERL 50 fs duration X-ray pulse at 8 keV.
Malware.inc: analyzing the security of popular web/mobile frameworks

Background and Objectives: A new generation of software emerged with mobile devices, cloud computing and the web. New usages come with new security threats, and a new generation of malware (malicious software) is emerging as well. Recent security reports show that these malware are on the increase. The goal of this project is to evaluate the risk of exposure to malware in popular app ecosystems such as Apple iOS, Google Android, Facebook, Google App Engine, Mozilla Firefox and Google Chrome. Methods: Eight students from Carnegie Mellon Qatar participated in this project. Each looked at a specific technology (either iOS, Android, Facebook, Google App, Mozilla Firefox or Google Chrome). The researchers learned how to develop applications and, as proof of concept, developed several malware apps that were able to steal user's personal information. One collects logins, passwords and credit card numbers from user's Gmail. One collects user's private information on Facebook and propagates through the victim's friends. One records the "clicking" passwords that users enter on online banking websites. One records keystrokes made on the computer without being detected by existing antivirus. One is an Android app that records people conversations while the phone is on standby mode. Results: Based on these experiments, we were able to assess the risks and analyze the security issues of these popular apps that we use everyday. These preliminary results were presented at 6th INTERPOL's Group meeting-MENA Region conference in Doha (March 22nd). We plan to publish the scientific results during the Fall of 2012. As future work, the security expertise gained during this project will allow us to design new security tools to protect users against these new kinds of malware. Conclusion: Qatar offers many services related to e-government, e-business, e-education and e-health through web portals and mobile applications. Deploying such a global infrastructure requires a strong security assurance. This project contributes to this vision by developing a local expertise on cyber security.
Comparison of Full-Scale Engine and Subscale Model Performance of a Mixed Flow Exhaust System for an Energy Efficient Engine (E3) Propulsion System

A full scale engine test of the NASA/General Electric Company (GE) Energy Efficient Engine (E3) was conducted to demonstrate the E3 engine concept and evaluate its performance. The test program, performed at the GE outdoor engine test facilities in Peebles, OH, included a detailed evaluation of the total pressure and temperature profiles at the exit of the mixed flow exhaust system to determine its mixing effectiveness. Subscale model tests of the same mixed flow exhaust system had been previously conducted at FluiDyne Engineering Corporation in Minneapolis, Minnesota as part of the GE E3 mixer aerodynamic technology development program. The scale model and full scale engine nozzle exit survey data and the calculated mixing effectiveness are compared and discussed. Results indicate the full scale engine mixing effectiveness to be five percent higher than the scale model as a result of a geometric difference and higher turbulence levels in the engne exhaust flowfield.
Polarizabilities of Ions in Perovskite-Type Crystals

Each type of ion is shown to have very nearly the same polarizability in different crystals of the perovskite type as well as in the diagonal cubic types reported previously. This conclusion is based on dielectric constant data for several titanates and zirconates and KMg${\mathrm{F}}_{3}$. The values of ionic polarizability are roughly proportional to the cube of the radius for ions in the same valence series.
Sexual dimorphism, survival, and parental investment in relation to offspring sex in a precocial bird

Differential growth rate between males and females, owing to a sexual size dimorphism, has been proposed as a mechanism driving sexâbiased survival. How parents respond to this selection pressure through sex ratio manipulation and sexâbiased parental investment can have a dramatic influence on fitness. We determined how differential growth rates during early life resulting from sexual size dimorphism affected survival of young and how parents may respond in a precocial bird, the black brant Branta bernicla nigricans. We hypothesized that more rapidly growing male goslings would suffer greater mortality than females during brood rearing and that parents would respond to this by manipulating their primary sex ratio and parental investment. Male brant goslings suffered a 19.5% reduction in survival relative to female goslings and, based on simulation, we determined that a female biased population sex ratio at fledging was never overcome even though previous work demonstrated a slight maleâbiased postâfledging survival rate. Contrary to the Fisherian sex ratio adjustment hypothesis we found that individual adult female brant did not manipulate their primary sex ratio (50.39% male, n =â645), in response to the sexâbiased population level sex ratio. However, female condition at the start of the parental care period was a good predictor of their primary sex ratio. Finally, we examined how females changed their behavior in response to primary sex ratio of their broods. We hypothesized that parents would take male biased broods to areas with increased growth rates. Parents with male biased primary sex ratios took broods to areas with higher growth rates. These factors together suggest that sexâbiased growth rates during early life can dramatically affect population dynamics through sexâbiased survival and recruitment which in turn affects decisions parents make about sex allocation and sexâbiased parental investment in offspring to maximize fitness.
Stability of periodic gravity waves in the presence of surface tension

Abstract The goal of this work is to investigate the effect of the inclusion of small surface tension on the instabilities of periodic gravity water waves that are present even in shallow water (Deconinck and Oliveras, 2011). Using the recent reformulation of Ablowitz, Fokas and Musslimani (2006), we compute periodic traveling water waves where the effects of both gravity and small surface tension are incorporated. The spectral stability of these solutions is examined using Hill’s method (Deconinck and Kutz, 2006). It is found that the instabilities are not suppressed by the inclusion of surface tension. In fact, the growth rates associated with them increase as the surface tension grows. Generalizing the work of MacKay and Saffman (1986), the persistence of these instabilities is confirmed analytically for waves of small amplitude.
The counterpoise method and bond functions in molecular dissociation energy calculations

Abstract The counterpoise method and bond functions are investigated by performing the complete fourth-order Moller—Plesset perturbation calculations for the molecular dissociation energies De of the ground state molecules N2 and HF, using a series of basis sets systematically extended with polarization functions and bond functions. The usefulness of bond functions is reliably confirmed by the present study but it is strikingly different from the result without corrections of the basis set superposition error. After the full counterpoise corrections, the calculated vaues of De are monotonically converged as bond functions and/or polarization functions are progressively added. The nearly converged values for N2 and HF are 98.4% and 99.0% of the experimental values. respectively.
USING EVIDENCE-BASED MEDICINE IN CLINICAL PRACTICE

Evidence-based health care has been described as a new paradigm for practicing medicine. 2 From the primary care physician's point of view, however, it might better be described as a formal combination of rigorous data and common sense. The common sense is the recognition that tests are worthwhile if they are reliable enough to change decision making. It is also the recognition that treatments are worthwhile if they lead to a better outcome valued by the patient: longer life, fewer symptoms, and particularly in the case of cancer, reduced fear. The rigorous component is the application of the basic science of clinical medicine, 12 clinical epidemiology. Initially, it may strike the reader as strange to suggest that the primary care physician should bring rigorous methods to the detection, diagnosis, and treatment of malignancies. No other area of medicine is more extensively researched in the hard sciences. Basic physiology, immunology, cell biology, and pharmacology have been and are being explored in great depth and detail, and chemotherapeutic regimens are evaluated in well-designed clinical trials. However, the degree of sophistication that characterizes basic research in cancer does not always extend to decision making in the clinic. The primary care physician often must be the one to ask the critical questions: •Will this test bring us news we can use? •How often is the information wrong? •Is there a treatment that makes patients better? •For whom does a treatment really work, how often does it work, and how well? Clinical epidemiology, as the basic science of primary care practice, provides the basis for framing and answering these questions. Evidence-based health care means deciding with the patient the course of testing or treatment based on real, data-based answers to these questions, rather than on the traditional experts' subjectively-interpreted clinical experience.
The Effects of Stress on Birth Weight in Low-Income, Unmarried Black Women

Objective Low birth weight leads to adverse health outcomes throughout life, is particularly high among Blacks, and may contribute to health disparities between Whites and Blacks in the United States. Stress is among the many potential contributors to birth weight, but key sources of stress have not yet been clearly identified. The objective of this paper is to describe the relationships between multiple sources of maternal stress and birth weight. Methods Linear regression is used to analyze data from two control groups ( n = 554) of the Nurse–Family Partnership trial in Memphis, Tennessee. Birth weight was obtained from medical records and other variables are from interviews during pregnancy (1990–1991). Four stresses were considered: abuse, anxiety, financial stress, and neighborhood disorganization. Results When the four sources of stress were included together in the same model and known non-stress-related influences were controlled for, only neighborhood was a significant contributor to birth weight. When each stress was entered into the model individually, abuse, anxiety, and neighborhood disorganization were all significant. Conclusion These results suggest that neighborhood disorganization has the most robust impact on birth weight, whereas abuse and anxiety seem to contribute via a source of shared variance. Further research is warranted to determine appropriate interventions.
Seriously ill patients' discussions of preparation and life completion: An intervention to assist with transition at the end of life

Objective: Patients approaching the end of life not only face challenges to physical well-being but also threats to emotional and spiritual integrity. Yet, identifying appropriate, effective, and brief interventions to address those concerns has proven elusive. We developed an intervention based on life review and emotional disclosure literatures and conducted a pilot study to determine feasibility and acceptability. This article presents qualitative intervention responses. Method: We conducted a three-armed randomized control trial to evaluate the effects of preparation and life completion discussion on health outcomes in patients with advanced serious illness. Hospice-eligible subjects were randomly assigned to one of three groups: (1) intervention (life completion discussion intervention), (2) attention control (relaxation meditation), and control (no intervention). Subjects in the intervention arm met with a facilitator three times. Session 1 focused on life story, Session 2 on forgiveness, and Session 3, on heritage and legacy. Results: Eighteen subjects participated in the pilot intervention interviews. Subjects from a range of socioeconomic backgrounds completed the intervention with equal facility. Results from Session 1 demonstrate narrative responses participants gave as they reconnected with previous life roles, values, and accomplishments. The second session illustrated reflections of choices one might have made differently and exploration of forgiveness offered and sought. Content from the first and second sessions laid the foundation for discussing Session 3’s lessons learned and heritage and legacy. Responses are summarized to assist clinicians in anticipating life review content that may improve overall quality of life at the end of life. Significance ofresults: Discussions of life completion may improve important health outcomes for patients at the end of life. This intervention may provide a brief, standardized, and transportable means for improving the quality of life of patients with advanced serious illness.
ACHAEUS POWELLI, A NEW SPIDER CRAB FROM NIGERIA (CRUSTACEA, DECAPODA, MAJIDAE)

ABSTRACT Achaeuspowelli is the seventh species of its genus to be recorded from West Africa. It is the first species to be taken within the Niger delta system. Among the more than 60 species of decapod crustaceans collected in the Niger delta by C. B. Powell (personal communication) of the University of Port Harcourt, Nigeria, is a series of a small Achaeus which represents an undescribed species. It is of interest inasmuch as it is the first species of the genus to be found in other than subtidal marine habitats off West Africa. The holotype of this new species has been deposited in the Rijksmuseum van Natuurlijke Historie, Leiden, The Netherlands; paratypes are in that institution and the National Museum of Natural History, Smithsonian Institution, Washington (USNM).
Short-Term Signatures of Evolutionary Change in the Salmonella enterica Serovar Typhimurium 14028 Genome

Salmonella enterica serovar Typhimurium is a Gram-negative pathogen that causes gastroenteritis in humans and a typhoid-like disease in mice and is often used as a model for the disease promoted by the human-adapted S. enterica serovar Typhi. Despite its health importance, the only S. Typhimurium strain for which the complete genomic sequence has been determined is the avirulent LT2 strain, which is extensively used in genetic and physiologic studies. Here, we report the complete genomic sequence of the S. Typhimurium strain 14028s, as well as those of its progenitor and two additional derivatives. Comparison of these S. Typhimurium genomes revealed differences in the patterns of sequence evolution and the complete inventory of genetic alterations incurred in virulent and avirulent strains, as well as the sequence changes accumulated during laboratory passage of pathogenic organisms.
A 10 YEAR EXPERIENCE OF OVER 100 FRONTOFACIAL PROCEDURES IN SYNDROMIC CHILDREN AND THEIR COMPLICATIONS

Complex craniofacial procedures form a distinct subgroup of transcranial or frontofacial surgery. The paediatric population undergoing these procedures mainly include the syndromic dysostoses, central facial hypoplasias or clefts and cranio-fronto-nasal dysplasia. We reviewed the case notes, hospital electronic records, logbooks and departmental database to review the series of frontofacial cases over the last 10 years. We collated demographic data, clinical diagnoses, operative records and episodic details. The unit has performed 105 frontofacial surgical procedures in children with Apert, Crouzon, Pfeiffer and other Syndromes. Within this population, it has been necessary to perform monobloc distractions, facial bipartition distractions, box osteotomies and facial bipartitions without distraction, as well as 2 Le Fort 3 advancements in combination with Fronto-orbital remodelling. During this period we have recorded 58 complications. From the patients that were investigated, there was a 9% major complication rate and 4% revision rate. Bipartition and box osteotomy procedures are significantly safer than distraction procedures. Overall, the main findings were as follows: • Peri-operative mortality rate 1% • Relapse rate 2% • Peri-operative massive transfusion risk 5% • Post-operative epilepsy for distraction 5% • Frontofacial surgery is comparable to other complex major surgeries • Distraction increases complication rate and doubles hospital stay but is still safe.
Bovine respiratory disease in feedlot cattle: phenotypic, environmental, and genetic correlations with growth, carcass, and longissimus muscle palatability traits.

Bovine respiratory disease (BRD) is the most costly feedlot disease in the United States. Selec- tion for disease resistance is one of several possible interventions to prevent or reduce the economic loss associated with animal disease and to improve animal welfare. Undesirable genetic relationships, however, may exist between production and disease resistance traits. The objectives of this study were to estimate the phenotypic, environmental, and genetic correlations of BRD with growth, carcass, and LM palatability traits. Health records on 18,112 feedlot cattle over a 15-yr period and slaughter data on 1,627 steers over a 4-yr period were analyzed with bivariate animal models. Traits included ADG, adjusted carcass fat thickness at the 12th rib, marbling score, LM area, weight of retail cuts, weight of fat trim, bone weight, Warner-Bratzler shear force, tenderness score, and juiciness score. The
A Real-Time SRP-PHAT Source Location Implementation using Stochastic Region Contraction(SRC) on a Large-Aperture Microphone Array

In most microphone array applications, it is essential to localize sources in a noisy, reverberant environment. It has been shown that computing the steered response power (SRP) is more robust than faster, two-stage, direct time-difference of arrival methods. The problem with computing SRP is that the SRP space has many local maxima and thus computationally-intensive grid-search methods are used to find a global maximum. Grid search is too expensive for a real-time system. Several papers have addressed this issue. In this paper we propose using stochastic region contraction (SRC) to make computing the SRP practical. We discuss one important SRP method, computing it from the phase transform (SRP-PHAT), review SRC, and show the computational saving. Using real data from human talkers, we show that SRC saves computation by more than two orders of magnitude with almost no loss in accuracy.
Microbial products trigger amino acid exudation from plant roots.

Plants naturally cycle amino acids across root cell plasma membranes, and any net efflux is termed exudation. The dominant ecological view is that microorganisms and roots passively compete for amino acids in the soil solution, yet the innate capacity of roots to recover amino acids present in ecologically relevant concentrations is unknown. We find that, in the absence of culturable microorganisms, the influx rates of 16 amino acids (each supplied at 2.5 μm) exceed efflux rates by 5% to 545% in roots of alfalfa (Medicago sativa), Medicago truncatula, maize (Zea mays), and wheat (Triticum aestivum). Several microbial products, which are produced by common soil microorganisms such as Pseudomonas bacteria and Fusarium fungi, significantly enhanced the net efflux (i.e. exudation) of amino acids from roots of these four plant species. In alfalfa, treating roots with 200 μm phenazine, 2,4-diacetylphloroglucinol, or zearalenone increased total net efflux of 16 amino acids 200% to 2,600% in 3 h. Data from 15N tests suggest that 2,4-diacetylphloroglucinol blocks amino acid uptake, whereas zearalenone enhances efflux. Thus, amino acid exudation under normal conditions is a phenomenon that probably reflects both active manipulation and passive uptake by microorganisms, as well as diffusion and adsorption to soil, all of which help overcome the innate capacity of plant roots to reabsorb amino acids. The importance of identifying potential enhancers of root exudation lies in understanding that such compounds may represent regulatory linkages between the larger soil food web and the internal carbon metabolism of the plant.
web2py for Scientific Applications

The needs of scientists to communicate effectively, collaborate over the Internet, and organize and present data in a structured and accessible manner have become critically important. The web2py framework offers rapid development and prototyping of secure database-driven Web applications and was created specifically with the scientific and academic communities in mind.
Pressure dependence of the reaction Cl + C2H2 over the temperature range 230 to 370 K

The pressure dependence of reaction (1), Cl + C2H2 + M → C2H2Cl + M, has been measured by a relative rate technique using the pressure independent abstraction reaction (2), Cl + C2H6 → C2H5 + HCl, as the reference. Values of k1/k2 were measured at pressures between 25 and 1300 torr at four temperatures ranging from 252 to 370 K, using air, N2, or SF6 diluent gases. Low pressure measurements (10–50 torr) were performed at 230 K. Assuming a temperature-independent center broadening factor of 0.6 in the Troe formalism and using the established value of k2, these data can be used to determine the temperature dependent high and low pressure limiting rate constants over the range of conditions studied in air for reaction (1): k∞(1) = 2.13 × 10−10 (T/300)−1.045 cm3/molecule-s; and k0(1) = 5.4 × 10−30 (T/300)−2.09 cm6/molecule2-s. Use of these expressions yields rate constants with an estimated 20% accuracy including uncertainty in the reference reaction. The data indicate that the rate constant for a typical stratospheric condition at 30 km altitude is approximately 50% of that previously estimated.
The dependent city

Placed within a larger politico-economic order, city governments are captives of many slowly changing forces that shape and limit community choices. This article seeks to conceptualize some of thes...
Arsenic speciation in marine certified reference materials

This study describes the analysis of arsenicals in three marine based certified reference materials (CRMs), DORM-2, DOLT-2 and TORT-2, all produced by the National Research Council of Canada. Extraction protocols involving accelerated solvent extraction (ASE) and sonication were investigated and arsenicals were determined on-line by anion-exchange and cation-exchange high-performance liquid chromatography (HPLC). The major species in all three tissues was found to be arsenobetaine (AsB), corresponding to 90%, 67% and 73% of the water-soluble arsenic in DORM-2, DOLT-2 and TORT-2, respectively. Other species quantified were arsenocholine (AsC+), tetramethylarsonium ion (TMAs+), trimethylarsonioproprionate (TMAP), dimethylarsenic acid (DMA), monomethylarsenic acid (MMA), arsenosugar D (As-sug D), arsenate (AsV) and arsenosugar A (As-sug A). The major species detected in all three materials were AsB and DMA, which together accounted for 97.4% (DORM-2), 95.4% (DOLT-2) and 91.7% (TORT-2) of the sum of the water soluble As species. The agreement for the determination of AsB by the different methods was good for all three materials, whereas some discrepancy was evident in the results for DMA. When an ASE approach with 50% acetic acid in methanol was used for the extraction, between 22% (DOLT-2) and 58% (TORT-2) more DMA was determined compared with extraction by sonication with water. Some discrepancy was evident between the sum of the species extracted and both the total As determined in the extracts and the certified As content based on complete digestion of the materials. The sum of the species recovered by sonication corresponded to 84% (DOLT-2) to 94% (DORM-2) of the total As determined in the aqueous extract. In comparison with the certified As content of the three materials, the sums of the extracted species range from 46% (DOLT-2) to 76% (TORT-2) and 102% (DORM-2).
How to explain why "unequal anisotropy ratios" is important using pictures but no mathematics.

Unequal anisotropy ratios" is an important property of cardiac tissue. Many of the fundamental mechanisms governing how the heart responds to an electrical shock require unequal anisotropy ratios. In this paper, I explain the role of unequal anisotropy ratios using pictures rather than mathematics. My goal is to help you develop physical insight, so you can better understand qualitatively why the condition of unequal anisotropy ratios is so important.
Aerosol filtration properties of nucleating agent containing electret filters

This study reports on the effects of nucleating agents on morphology, charging, and electrostatic filtration performance of polypropylene meltblown webs. Two commercial nucleating agents, DMDBS (3:2, 4-bis(3,4-dimethyldibenzylidene) sorbitol) and NA11 (sodium 2,2′-methylene-bis(4,6-di-tertbutylphenyl)-phosphate) were compared. It is hypothesized that faster solidification brought about by the addition of the nucleating agents may be responsible for the slight increase in fiber diameter and concomitant reduction in web solidity. Samples were charged at room temperature as well as at elevated temperatures. Upon thermal charging, significant enhancement in the electrostatic potential and filtration performance of the webs was observed. Particularly, the stability of electrostatic filtration performance was found to be promising with the addition of these polarizable additives. Dielectric spectroscopy tests confirmed an increase in capacitance for samples containing nucleating agents. POLYM. ENG. SCI., 54:1533–1539, 2014. © 2013 Society of Plastics Engineers
Riboflavin Utilization by a Mutant Strain of Single Comb White Leghorn Chickens 3. Riboflavin Content of Tissues

Abstract PREVIOUS studies of the physiological characteristics of a mutant strain of Single Comb White Leghorn chickens have shown that the free riboflavin in the blood fails to increase at the onset of egg production (Maw, 1954; and Boucher et al., 1959). Isotopic tracer studies have shown that free riboflavin is absorbed normally from the digestive tract (Cowan et al., 1964). It thus appears that the event or events which prevent its accumulation in the blood must take place after absorption. The purpose of the work reported in this paper was to investigate the possibility that riboflavin may be destroyed in the tissues of the recessive hen after absorption. METHODS AND MATERIALS The fluorometric method described by Burch et al. (1948) and Bessey et al. (1949) was used for the assay of free riboflavin, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). The phenol extraction procedure of Crammer (1948) was employed …
Focused ion beam milling of vitreous water: prospects for an alternative to cryo‐ultramicrotomy of frozen‐hydrated biological samples

Summary The feasibility of using a focused ion beam (FIB) for the purpose of thinning vitreously frozen biological specimens for transmission electron microscopy (TEM) was explored. A concern was whether heat transfer beyond the direct ion interaction layer might devitrify the ice. To test this possibility, we milled vitreously frozen water on a standard TEM grid with a 30-keV Ga+ beam, and cryo-transferred the grid to a TEM for examination. Following FIB milling of the vitreous ice from a thickness of approximately 1200 nm to 200–150 nm, changes characteristic of heat-induced devitrification were not observed by TEM, in either images or diffraction patterns. Although numerous technical challenges remain, it is anticipated that ‘cryo-FIB thinning’ of bulk frozen-hydratred material will be capable of producing specimens for TEM cryo-tomography with much greater efficiency than cryo-ultramicrotomy, and without the specimen distortions and handling difficulties of the latter.
Baculovirus Expression of BmAChE3, a cDNA Encoding an Acetylcholinesterase of Boophilus microplus (Acari: Ixodidae)

The complete cDNA sequence encoding a Boophilus microplus (Canestrini) (Acari: Ixodidae) acetylcholinesterase (AChE3) was expressed in the baculovirus system. The recombinant AChE3 protein (rBmAChE3) was secreted as a soluble form into the cell culture medium and was identified as a functional AChE by substrate specificity and by inhibition with the AChE-specific inhibitors eserine sulfate and BW284c51. Inhibition kinetics of rBmAChE3, in the presence of the organophosphate paraoxon, revealed sensitivity comparable with that of adult, organophosphate-susceptible neural AChE. To our knowledge, this is the first report of the cloning and successful expression of a functional ixodid AChE.
Corporate Inversion: A Symbol Of A Changing Paradigm Of Corporate Behavior? Balancing Global Competitiveness, Fiduciary Duty, And Ethical Behavior

Global competitiveness is affecting U.S Companies in a variety of ways. One is tax policy. U.S. federal tax policy in a global environment causes many U.S.-based companies to operate at a disadvantage to some foreign competitors. Current U.S. tax laws require domestic residents to pay income taxes on worldwide income. However, many countries have tax systems that exempt from domestic taxation profits earned by foreign subsidiaries. In addition, U.S. corporations with foreign-source income may be subject to tax by the country in which the income is earned. In an effort to eliminate this competitive burden, a growing number of U.S.-based companies have engaged in corporate inversion transactions. U.S.-based companies need to reconcile their fiduciary duty to shareholders with fundamental ethical issues as well as federal tax policy in justifying moving to another country solely for its beneficial tax system.
Architecture and Systems Ecology: Thermodynamic Principles of Environmental Building Design, in three parts

Modern buildings are both wasteful machines that can be made more efficient and instruments of the massive, metropolitan system engendered by the power of high-quality fuels. A comprehensive method of environmental design must reconcile the techniques of efficient building design with the radical urban and economic reorganization that we face. Over the coming century, we will be challenged to return to the renewable resource base of the eighteenth-century city with the knowledge, technologies, and expectations of the twenty-first-century metropolis. This book explores the architectural implications of systems ecology, which extends the principles of thermodynamics from the nineteenth-century focus on more efficient machinery to the contemporary concern with the resilient self-organization of ecosystems. Written with enough technical material to explain the methods, it does not include in-text equations or calculations, relying instead on the energy system diagrams to convey the argument. Architecture and Systems Ecology has minimal technical jargon and an emphasis on intelligible design conclusions, making it suitable for architecture students and professionals who are engaged with the fundamental issues faced by sustainable design. The energy systems language provides a holistic context for the many kinds of performance already evaluated in architecture—from energy use to material selection and even the choice of building style. It establishes the foundation for environmental principles of design that embrace the full complexity of our current situation. Architecture succeeds best when it helps shape, accommodate, and represent new ways of living together.
Attitudes towards Old Age: A Study of the Self-Image of Aged

Aging occurs in a societal context, ranging from the micro scale of the family to the macro scale of the society. This context includes the attitudes, stereotypes and age norms, which determine age...
Seeding atomic layer deposition of alumina on graphene with yttria.

Integrating graphene into nanoelectronic device structure requires interfacing graphene with high-κ dielectric materials. However, the dewetting and thermal instability of dielectric layers on top of graphene makes fabricating a pinhole-free, uniform, and conformal graphene/dielectric interface challenging. Here, we demonstrate that an ultrathin layer of high-κ dielectric material Y2O3 acts as an effective seeding layer for atomic layer deposition of Al2O3 on graphene. Whereas identical Al2O3 depositions lead to discontinuous film on bare graphene, the Y2O3 seeding layer yields uniform and conformal films. The morphology of the Al2O3 film is characterized by atomic force microscopy and transmission electron microscopy. C-1s X-ray photoemission spectroscopy indicates that the underlying graphene remains intact following Y2O3 seed and Al2O3 deposition. Finally, photoemission measurements of the graphene/SiO2/Si, Y2O3/graphene/SiO2, and Al2O3/Y2O3/graphene/SiO2 interfaces indicate n-type doping of graphene w...
SHAPING THE TRANSMISSIBILITY FOR SIX-AXIS ACTIVE VIBRATION ISOLATORS

A study of several of the most important aspects of sixaxis hexapods used for isolation is conducted. The ideal transmissibility can be shaped by changing the hardware configuration, changing the sensors and actuators in active isolation, and shaping within the control design. The University of Washington hexapod is unique in its low comer frequency, its large actuator stroke, its number of sensors, and its ability to be reconfigured. This study examines several issues including: changing the passive corner frequency, wire harnesses, control sensors and topology, and control design. Experimental results of six-axis isolation validate the results.
Rotational wave-packet imaging of molecules

We propose and illustrate numerically the possibility of imaging rotational wave packets in angular space and time by using different pump-probe spectroscopic techniques. A general theoretical framework to perform such rotational mapping is derived and three specific spectroscopies, namely, birefringence, high harmonic generation, and angle-resolved photoelectron spectroscopy, are numerically explored. All three approaches are shown to provide direct mapping of the rotational coherences of molecules but they are not equivalent; comparison of their results yields interesting insights into their relative merits. Finally, we illustrate the role played by the symmetry of the molecular orbitals in determining the quality of the images generated by high harmonic and photoelectron signals. The potential of rotational imaging as a route to both intramolecular coupling mechanisms and the interaction of molecules with different environments is discussed.
Use of Algebraic-Stress Model for determination of near-wall Reynolds-Stresses in turbulent flow over a flat plate

The algebraic stress model (ASM) is investigated for the problem of spatially developing zero-pressure-gradient boundary layer for the steady state turbulent flow of air over a 2D flat plate. For a region very close to the wall, the convection and diffusion transport terms of the governing equations for the Reynolds stresses can be approximated with simpler terms, and therefore, there would no longer be a need to solve the transport equations. The system of highly coupled non-linear algebraic equations is then solved for all of the Reynolds stress components in the near-wall region. Different versions of the pressure-strain term will be considered, e.g., with and without the wall effect, and compact vs. complete form of the pressure strain formulation arising from the presence of the mean rate of strain, as well as the explicit ASM. MATLAB software package is used in order to solve the system of algebraic equations for Reynolds stresses. The initial guesses for all of the Reynolds stresses are obtained by solving the turbulent flow in the domain of interest using the Reynolds Stress turbulence model in ANSYS Fluent for a few iterations. The estimates for mean velocity gradients, and turbulent dissipation rate are taken from Fluent as well. The ASM calculations are carried out at positions with the Reynolds number Rex of 3.2e6 and 4e6 along the plate and for all of the grid points sufficiently close to the plate. Based on the current results, the Reynolds stresses predicted by ASM and RSM are quite similar, and they are both close to the well accepted published experimental data. More investigation on benefits of ASM has to be carried out, before extending its use to more complicated geometries.
Genotyping and antibiotic resistance of prevalent food-borne pathogenic bacteria in Ningbo

Objective To investigate the species of foodborne pathogenic bacteria,antibiotic resistance and genotypes of the epidemic strains,in order to provide basis to trace the infectious source. Methods The pathogenic bacteria were isolated through direct isolation and enrichment isolation,identified with biochemistry and API method,and typed with serum agglutination and PFGE method. The antibiotic resistance was tested with K-B method,while the resistance genes and virulence genes were detected with PCR. Results A total of 3473 food-borne pathogenic bacteria strains in 16 species of 8 categories were detected from 9256 specimens,and the positive rate was 37. 52%. The most common pathogen was Vibrio parahaemolyticus,the detection rate was significantly different from the other pathogenic bacteria( P 0. 05). Serotyping revealed that the dominant bacteria of Vibrio parahaemolyticus was O3 group,that of Salmonella was paratyphi A,that of Shigella was Shigella flexneri and that of Escherichia coli was pathogenic Escherichia coli O119. Nineteen genotypes of Vibrio parahaemolyticus,3 genotypes of Salmonella typhi,and 12 genotypes of Salmonella paratyphi A were identified with PFGE. Conclusion Vibrio parahaemolyticus is the most common species in various foodborne pathogenic bacteria in Ningbo city. Clustering analysis can provide foundation for epidemiological track to trace the bacterial sources. Pathogenic bacteria are sensitive to various antibiotics,2. 45% of the isolates in certain species are ESBL,showing the complexity of resistant strains.
Does Research on Constitutions Matter

Alan Kuperman and his colleagues have brought us a most sophisticated study of the impact of constitutional designs on conflict management in Africa. Their insights are equally relevant to other pa...