cssi/SciSciGPT-SciSciNet huggingface dataset:
Required Allosteric Effector Site for N-Acetylglutamate on Carbamoyl-Phosphate Synthetase I

Abstract Carbamoyl-phosphate synthetase I (CPSase I) catalyzes the entry and rate-limiting step in the urea cycle, the pathway by which mammals detoxify ammonia. One facet of CPSase I regulation is a requirement for N-acetylglutamate (AGA), which induces an active enzyme conformation and does not participate directly in the chemical reaction. We have utilized labeling with carbodiimide-activated [14C]AGA to identify peptides 120-127, 234-237, 625-630, and 1351-1356 as potentially being near the binding site for AGA. Identification of peptide 1351-1356 confirms the previous demonstration (Rodriquez-Aparicio, L. B., Guadalajara, A. M., and Rubio, V. (1989) Biochemistry 28, 3070-3074) that the C-terminal region is involved in binding AGA. Identification of peptides 120-127 and 234-237 constitutes the first evidence that the N-terminal region of the synthetase is involved in ligand binding. Since peptides 631-638 and 1327-1348 have been identified near the ATP site of CPSase I (Potter, M. D., and Powers-Lee, S. G. (1992) J. Biol. Chem. 267, 2023-2031), the present finding of involvement of peptides 625-630 and 1351-1356 at an “allosteric” activator site was unexpected. The idea that portions of the AGA effector site might be derived from an ancestral glutamine substrate site via a gene duplication and diversification event was considered.
Recommended survey designs for occupancy modelling using motion-activated cameras: insights from empirical wildlife data

Motion-activated cameras are a versatile tool that wildlife biologists can use for sampling wild animal populations to estimate species occurrence. Occupancy modelling provides a flexible framework for the analysis of these data; explicitly recognizing that given a species occupies an area the probability of detecting it is often less than one. Despite the number of studies using camera data in an occupancy framework, there is only limited guidance from the scientific literature about survey design trade-offs when using motion-activated cameras. A fuller understanding of these trade-offs will allow researchers to maximise available resources and determine whether the objectives of a monitoring program or research study are achievable. We use an empirical dataset collected from 40 cameras deployed across 160 km(2) of the Western Slope of Colorado, USA to explore how survey effort (number of cameras deployed and the length of sampling period) affects the accuracy and precision (i.e., error) of the occupancy estimate for ten mammal and three virtual species. We do this using a simulation approach where species occupancy and detection parameters were informed by empirical data from motion-activated cameras. A total of 54 survey designs were considered by varying combinations of sites (10-120 cameras) and occasions (20-120 survey days). Our findings demonstrate that increasing total sampling effort generally decreases error associated with the occupancy estimate, but changing the number of sites or sampling duration can have very different results, depending on whether a species is spatially common or rare (occupancy = ψ) and easy or hard to detect when available (detection probability = p). For rare species with a low probability of detection (i.e., raccoon and spotted skunk) the required survey effort includes maximizing the number of sites and the number of survey days, often to a level that may be logistically unrealistic for many studies. For common species with low detection (i.e., bobcat and coyote) the most efficient sampling approach was to increase the number of occasions (survey days). However, for common species that are moderately detectable (i.e., cottontail rabbit and mule deer), occupancy could reliably be estimated with comparatively low numbers of cameras over a short sampling period. We provide general guidelines for reliably estimating occupancy across a range of terrestrial species (rare to common: ψ = 0.175-0.970, and low to moderate detectability: p = 0.003-0.200) using motion-activated cameras. Wildlife researchers/managers with limited knowledge of the relative abundance and likelihood of detection of a particular species can apply these guidelines regardless of location. We emphasize the importance of prior biological knowledge, defined objectives and detailed planning (e.g., simulating different study-design scenarios) for designing effective monitoring programs and research studies.
Spontaneous unilateral dizygotic twin tubal pregnancy.

Spontaneous dizygotic unilateral twin tubal pregnancy is an extremely rare occurrence with a high risk for pregnancy-related mortality, and a diagnostic challenge for obstetricians. We present a case of a 27-year-old woman with spontaneous twin tubal pregnancy. Transvaginal color Doppler sonography revealed 2 separate gestational sacs within the right adnexa, each containing an embryo. Cytogenetic examination of the trophoblastic tissues confirmed the diagnosis of dizygotic twin ectopic pregnancy. Clinical signs and symptoms together with imaging studies help in the diagnosis of this rare variant of ectopic pregnancies. © 2008 Wiley Periodicals, Inc. J Clin Ultrasound, 2009
Growth, Nitrogen Fixation, and Spectral Attenuation in Cultivated Trichodesmium Species

Physiological studies of Trichodesmium species have been hindered by difficulties in maintaining actively growing, nitrogen-fixing cultures. Previous cultivation successes have not been widely duplicated. We present here a simple modified seawater medium and handling techniques which have been used to maintain actively growing Trichodesmium thiebautii in laboratory culture for over 1 year. The cultured population, isolated from coastal Atlantic waters, has a growth rate of 0.23 division day and exhibits light-dependent nitrogen fixation during exponential growth. Various morphologies, including solitary trichomes, and aggregates (spherical puffs and fusiform tufts) are present during growth. Spectral and scalar irradiance were measured within naturally occurring (coastal Atlantic) aggregates with small (diameter, 50 to 70 mum) spherical fiber-optic sensors. In contrast to naturally occurring puffs, cultivated Trichodesmium aggregates exhibited spectral properties consistent with low-light adaptation. Cultivated puff-type aggregates were also examined by using oxygen microelectrodes. The simple medium and approach used for cultivation should be easily reproducible and amenable to further manipulations and modifications useful for physiological studies of Trichodesmium spp. in culture.
Harmonic Silhouette Matching for 3D Models

The ability to perform fast retrieval from a database of 3D models is becoming a growing necessity as the number of models in circulation is rapidly increasing. Several of the many existing methods dealing with this problem consider similarity measures based on visual appearance. This idea of comparing models using their respective silhouettes performs well on a number of benchmarks, but comes with a few inherent limitations, the biggest of which is that at the time of comparison all possible rotational alignments between two models need to be considered. In this paper we present two retrieval algorithms based on a silhouette representation. The first method shows how model similarity can be computed using fast harmonic matching techniques, and the second method reduces the problem to fast vector differencing using rotation-invariant properties of the representations.
Solution deposition of amorphous IZO films by ultrasonic spray pyrolysis

Atmospheric-pressure solution deposition of the transparent conducting oxide (TCO), amorphous indium-zinc oxide (α-IZO), was investigated as an alternative to traditional vacuum-based physical vapor deposition techniques for photovoltaic applications. Solution processing is attractive due to its ease and potential to lower device manufacturing costs. Here we report on α-IZO films prepared by ultrasonic spray pyrolysis from solutions of an indium-zinc formate (IZF) precursor. Thin, crack-free, amorphous IZO films with good optical transmittance (≫75%) and conductivities of ∼34 S/cm were produced from an IZF-HNO 3 -methanol ink using joint RTP and Ar-H 2 annealing.
Transcriptional regulation of fetal to adult hemoglobin switching: new therapeutic opportunities

In humans, embryonic, fetal, and adult hemoglobins are sequentially expressed in developing erythroblasts during ontogeny. For the past 40 years, this process has been the subject of intensive study because of its value to enlighten the biology of developmental gene regulation and because fetal hemoglobin can significantly ameliorate the clinical manifestations of both sickle cell disease and β-thalassemia. Understanding the normal process of loss of fetal globin expression and activation of adult globin expression could potentially lead to new therapeutic approaches for these hemoglobin disorders. Herein, we briefly review the history of the study of hemoglobin switching and then focus on recent discoveries in the field that now make new therapeutic approaches seem feasible in the future. Erythroid-specific knockdown of fetal gene repressors or enforced expression of fetal gene activators may provide clinically applicable approaches for genetic treatment of hemoglobin disorders that would benefit from increased fetal hemoglobin levels.
Construction Site Safety Roles

A survey of design engineers, general contractors, and subcontractors indicates there is not uniform agreement on the site safety responsibilities that should be assumed by each of these groups. Possible explanations for this lack of shared expectations regarding site safety roles are discussed. It is suggested that specific site safety responsibilities be assigned on future projects based on each group's ability to control the factors needed to prevent eight root causes of construction accidents.
Iterative Refinement on FPGAs

Achievable accuracy for mixed precision iterative refinement depends on the precisions supported by computing platforms. Even though the arithmetic unit precision can be flexible for programmable logic computing architectures (e.g. FPGAs), previous work rarely discusses the performance benefits due to enabling flexible achievable accuracy. Hence, we propose an iterative refinement approach on FPGAs which employs an arbitrary precision for the iterative refinement to obtain an arbitrary accuracy. We implement single processing elements for the refinement on the Xilinx XC5VLX110T and compare them to Xilinx XC6VSX475T for performance estimation. This paper shows that the performance is similar to the NVIDIA GTX480 when a user requires accuracies between single and double precision, but the implementation can also produce beyond double precision accuracy.
The Reconstruction of Social Ecology and Neighborhood Change in Brooklyn

Social ecology, despite the grave errors made by the Chicago School, still offers insights into the mechanics underlying the formation of urban residential geographies. A reconstituted social ecology, properly grafted to a conception of the division of labor and informed by structuration theory, reveals much about neighborhood formation and dissolution, urban sociospatial mobility, and the neglected issue of ethnicity. In this paper such a project is outlined, and then utilized empirically with a case study of the historical and current evolution of Brooklyn, New York, illustrating that the formation and dissolution of neighborhoods is a function of the changing types of jobs at successive historical moments, the structure of the housing market, the geography of preexisting residential formations, and the cultural and ideological characteristics of immigrant communities.
An Energy Barrier Framework for the Limits of Charge, Spin and Optical Switches

A generic abstraction for a binary switch is described and related to the operational properties of three physical implementations: charge, spin and optical. For a system at equilibrium with thermal environment, an energy barrier is needed to separate two distinguishable states. We utilize the fundamental concept of the energy barrier to study limiting characteristics of these three classes of binary switch. Some of the technical challenges that must be overcome if spin-based binary switch are to find widespread application are discussed
Cost-driven layout for thin-film MCMs

The authors point out that the SURF rubber-band router is designed to meet many of the needs of thin-film MCM layout that are not met by existing PCB tools. The ways that SURF can exploit the flexibility of the rubber-band wiring model to generate layouts that help reduce substrate cost are discussed. Specifically, approaches for reducing the number of metal layers and increasing substrate yield are presented. The results of applying these techniques to several MCM designs are shown. Finally, some future directions for research are described. >
Chronic Administration of 2-Acetylaminofluorene Alters the Cellular Iron Metabolism in Rat Liver

Dysregulated intracellular iron homeostasis has been found not only in rodent and human hepatocellular carcinomas but also in several preneoplastic pathological states associated with hepatocarcinogenesis; however, the precise underlying mechanisms of metabolic iron disturbances in preneoplastic liver and the role of these disturbances remain unexplored. In the present study, using an in vivo model of rat hepatocarcinogenesis induced by 2-acetylaminofluorene, we found extensive alterations in cellular iron metabolism at preneoplastic stages of liver carcinogenesis. These were characterized by a substantial decrease in the levels of cytoplasmic non-heme iron in foci of initiated hepatocytes and altered expression of the major genes responsible for the proper maintenance of intracellular iron homeostasis. Gene expression analysis revealed that the decreased intracellular levels of iron in preneoplastic foci might be attributed to increased iron export from the cells, driven by upregulation of ferroportin (Fpn1), the only known non-heme iron exporter. Likewise, increased Fpn1 gene expression was found in vitro in TRL1215 rat liver cells with an acquired malignant phenotype, suggesting that upregulation of Fpn1 might be a specific feature of neoplastically transformed cells. Other changes observed in vivo included the downregulation of hepcidin (Hamp) gene, a key regulator of Fpn1, and this was accompanied by decreased levels of CCAAT/enhancer binding proteins alpha and beta, especially at the Hamp promoter. In conclusion, our results demonstrate the significance of altered intracellular iron metabolism in the progression of liver carcinogenesis and suggest that correction of these alterations could possibly affect liver cancer development.
Quantifying the Causes of Path Inflation

Researchers have shown that the Internet exhibits path inflation ‐ end-to-end paths can be significantly longer than necessary. We present a trace-driven study of 65 ISPs that characterizes the root causes of path inflation, namely topology and routing policy choices within an ISP, between pairs of ISPs, and across the global Internet. To do so, we develop and validate novel techniques to infer intra-domain and peering policies from end-to-end measurements. We provide the first measured characterization of ISP peering policies. In addition to “early-exit,” we observe a significant degree of helpful non-early-exit, load-balancing, and other policies in use between peers. We find that traffic engineering (the explicit addition of policy constraints on top of topology constraints) is widespread in both intra- and inter-domain routing. However, intra-domain traffic engineering has minimal impact on path inflation, while peering policies and inter-domain routing lead to significant inflation. We argue that the underlying cause of inter-domain path inflation is the lack of BGP policy controls to provide convenient engineering of good paths across ISPs.
Vitamin D receptors from patients with resistance to 1,25-dihydroxyvitamin D3: point mutations confer reduced transactivation in response to ligand and impaired interaction with the retinoid X receptor heterodimeric partner.

Hereditary hypocalcemic vitamin D-resistant rickets is attributable to defects in the nuclear receptor for 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]. Two novel point mutations (I314S and R391C) identified in the hormone-binding domain of the human vitamin D receptor (VDR) from patients with hereditary hypocalcemic vitamin D-resistant rickets confer the receptor with sharply reduced 1,25-(OH)2D3-dependent transactivation. These natural mutations, especially R391C, also lead to a second specific consequence, namely impaired heterodimeric interaction with retinoid X receptor (RXR). While the transactivation ability of the I314S mutant can be largely restored by providing excess 1,25-(OH)2D3, R391C activity is more effectively restored with exogenous RXR. These observations are reflected also in the clinical course of each patient: the patient bearing the I314S mutation showed a nearly complete cure with pharmacological doses of a vitamin D derivative, whereas the patient bearing R391C responded only partially ...
Perlecan, a candidate gene for the CAPB locus, regulates prostate cancer cell growth via the Sonic Hedgehog pathway

Genetic studies associated the CAPB locus with familial risk of brain and prostate cancers. We have identified HSPG2 (Perlecan) as a candidate gene for CAPB. Previously we have linked Perlecan to Hedgehog signaling in Drosophila. More recently, we have demonstrated the importance of Hedgehog signaling in humans for advanced prostate cancer. Here we demonstrate Perlecan expression in prostate cancer, and its function in prostate cancer cell growth through interaction and modulation of Sonic Hedgehog (SHH) signaling. Perlecan expression in prostate cancer tissues correlates with a high Gleason score and rapid cell proliferation. Perlecan is highly expressed in prostate cancer cell lines, including androgen insensitive cell lines and cell lines selected for metastatic properties. Inhibition of Perlecan expression in these cell lines decreases cell growth. Simultaneous blockade of Perlecan expression and androgen signaling in the androgen-sensitive cell line LNCaP was additive, indicating the independence of these two pathways. Perlecan expression correlates with SHH in tumor tissue microarrays and increased tumor cell proliferation based on Ki-67 immunohistochemistry. Inhibition of Perlecan expression by siRNA in prostate cancer cell lines decreases SHH signaling while expression of the downstream SHH effector GLI1 rescues the proliferation defect. Perlecan forms complexes with increasing amounts of SHH that correlate with increasing metastatic potential of the prostate cancer cell line. SHH signaling also increases in the more metastatic cell lines. Metastatic prostate cancer cell lines grown under serum-starved conditions (low androgen and growth factors) resulted in maintenance of Perlecan expression. Under low androgen, low growth factor conditions, Perlecan expression level correlates with the ability of the cells to maintain SHH signaling. We have demonstrated that Perlecan, a candidate gene for the CAPB locus, is a new component of the SHH pathway in prostate tumors and works independently of androgen signaling. In metastatic tumor cells increased SHH signaling correlates with the maintenance of Perlecan expression and more Perlecan-SHH complexes. Perlecan is a proteoglycan that regulates extracellular and stromal accessibility to growth factors such as SHH, thus allowing for the maintenance of SHH signaling under growth factor limiting conditions. This proteoglycan represents an important central regulator of SHH activity and presents an ideal drug target for blocking SHH effects.
Distinguishing coevolution from covicariance in an obligate pollination mutualism: asynchronous divergence in Joshua tree and its pollinators.

Obligate pollination mutualisms-–in which both plants and their pollinators are reliant upon one another for reproduction-–represent some of the most remarkable coevolutionary interactions in the natural world. The intimacy and specificity of these interactions have led to the prediction that the plants and their pollinators may be prone to cospeciation driven by coevolution. Several studies have identified patterns of phylogenetic congruence that are consistent with this prediction, but it is difficult to determine the evolutionary process that underlies these patterns. Phylogenetic congruence might also be produced by extrinsic factors, such as a shared biogeographic history. We examine the biogeographic history of a putative case of codivergence in the obligate pollination mutualism between Joshua trees (Yucca brevifolia) and two sister species of pollinating yucca moths (Tegeticula spp.) We employ molecular phylogenetic methods and coalescent-based approaches, in combination with relaxed-clock estimates of absolute rates of molecular evolution, to analyze multi-locus sequence data from more than 30 populations of Y. brevifolia and its pollinators. The results indicate that the moth species diverged significantly (p < 0.01) more recently than their corresponding host populations, suggesting that the apparent codivergence is not an artifact of a shared biogeographic history.
The cyclin D1b splice variant: an old oncogene learns new tricks

The function of cyclin D1 as a positive regulator of the cell cycle and proto-oncogene has been well established. Cyclin D1 elicits its pro-proliferative function early in G1 phase, through its ability to activate cyclin dependent kinase (CDK) 4 or 6. Active CDK4/6-cyclin D1 complexes phosphorylate substrates that are critical for modulating G1 to S phase progression, and in this manner promote cellular proliferation. Emerging data from a number of model systems revealed that cyclin D1 also holds multiple, kinase-independent cellular functions. First, cyclin D1 assists in sequestering CDK inhibitors (e.g. p27kip1), thus bolstering late G1 CDK activity. Second, cyclin D1 is known to bind and modulate the action of several transcription factors that hold significance in human cancers. Thus, cyclin D1 impinges on several distinct pathways that govern cancer cell proliferation. Although intragenic somatic mutation of cyclin D1 in human disease is rare, cyclin D1 gene translocation, amplification and/or overexpression are frequent events in selected tumor types. Additionally, a polymorphism in the cyclin D1 locus that may affect splicing has been implicated in increased cancer risk or poor outcome. Recent functional analyses of an established cyclin D1 splice variant, cyclin D1b, revealed that the cyclin D1b isoform harbors unique activities in cancer cells. Here, we review the literature implicating cyclin D1b as a mediator of aberrant cellular proliferation in cancer. The differential roles of cyclin D1 and the cyclin D1b splice variant in prostate cancer will be also be addressed, wherein divergent functions have been linked to altered proliferative control.
Body mass index, weight gain, and risk of endometrial cancer.

Abstract Excess weight near the time of diagnosis is a well‐established risk factor for endometrial cancer; less is known about the influence of weight at earlier periods of a woman's life or weight gain in adulthood In a case‐control study in western New York State, interviews were conducted with 232 incident endometrial cancer cases, diagnosed between 1986 and 1991, and 631 community controls. Body mass index at 16 years of age and 20,10, and 2 years before interview and changes in body mass index between these time periods were examined. While being relatively heavy at 16 years of age was associated with slightly increased risk [adjusted odds ratio (OR) = 1.28, 95% confidence interval (CI) = 0.84–1.96], large gains over the entire period from 16 years of age to 2 years ago (OR = 3.45, CI = 2.13–5.57) and high body mass index close to the time of diagnosis (OR = 3.21, CI = 2.01–5.15) were associated with greater risk. Differences in mean body mass index between cases and controls increased over time.
CLAM DENSITY AND SCAUP FEEDING BEHAVIOR IN SAN PABLO BAY, CALIFORNIA

Abstract San Pablo Bay, in northern San Francisco Bay, California, is an important wintering area for Greater (Aythya marila) and Lesser Scaup (A. affinis). We investigated variation in foraging behavior of scaup among five sites in San Pablo Bay, and whether such variation was related to densities of their main potential prey, the clams Potamocorbula amurensis and Macoma balthica. Time-activity budgets showed that scaup spent most of their time sleeping at some sites, and both sleeping and feeding at other sites, with females feeding more than males. In the first half of the observation period (12 January–5 February 2000), percent time spent feeding increased with increasing density of P. amurensis, but decreased with increasing density of M. balthica (diet studies have shown that scaup ate mostly P. amurensis and little or no M. balthica). Densities of M. balthica stayed about the same between fall and spring benthic samples, while densities of P. amurensis declined dramatically at most sites. In the se...
Network Cost Minimization for Mobile Data Gathering in Wireless Sensor Networks

Recent studies have shown that significant benefit can be achieved in wireless sensor networks (WSNs) by employing mobile collectors for data gathering via short-range communications. A typical scenario for such a scheme is that a mobile collector roams over the sensing field and pauses at some anchor points on its moving tour such that it can traverse the transmission range of all the sensors in the field and directly collect data from each sensor. In this paper, we study the performance optimization of such mobile data gathering by formulating it into a cost minimization problem constrained by channel capacity, required minimum data uploads from each sensor and bound of total sojourn time at all anchor points. In order to provide an efficient and distributed algorithm, we decompose this global optimization problem into two subproblems that can be solved by each sensor and the mobile collector, respectively. We show that such decomposition can be characterized as a pricing mechanism, in which each sensor independently adjusts its payment for the data uploading opportunity based on the shadow prices of different anchor points. Correspondingly, we give an efficient algorithm to jointly solve the two subproblems. Our theoretical analysis demonstrates that the proposed algorithm can achieve the optimal data control for each sensor and the optimal sojourn time allocation for the mobile collector, which minimizes the overall network cost. Finally, extensive simulation results further validate that our algorithm achieves lower cost than the compared data gathering strategy.
Dynamic Structure of Peptides Studied By Multinuclear NMR

One experimental approach to determining the dynamic interconversion around a single bond is to measure multiple vicinal NMR couplings about it. This approach (“circumjacent coupling”) has been extensively applied by us to investigate x1 angles in the side chains of residues in the peptide hormones oxytocin and [8–arginine] vasopressin. The criteria for discriminating rotamer-averaged and predominantly fixed torsion angles have been developed. This approach provides detailed probes of conformation in the peptides, demonstrating the apparent conformational independence of the terminal tripeptide section, the insensitivity of side chain conformation to adjacent substitutions of residues, and the relative rigidity of the disulfide bridge region in the rings of these peptides.
Advances in Multidetector CT Diagnosis of Pediatric Pulmonary Thromboembolism

Although pediatric pulmonary thromboembolism is historically believed to be rare with relatively little information available in the medical literature regarding its imaging evaluation, it is more common than previously thought. Thus, it is imperative for radiologists to be aware of the most recent advances in its imaging information, particularly multidetector computed tomography (MDCT), the imaging modality of choice in the pediatric population. The overarching goal of this article is to review the most recent updates on MDCT diagnosis of pediatric pulmonary thromboembolism.
GENETIC ANALYSIS OF THE STANFORD LRC FAMILY STUDY DATA I. STRUCTURED EXPLORATORY DATA ANALYSIS OF HEIGHT AND WEIGHT MEASUREMENTS

A new methodology for determining mode for inheritance of continuously distributed traits in nuclear families, structured exploratory data analysis (SEDA), is described and applied to height and weight measurements. The family data were collected as part of the Lipid Research Clinic's collaborative study (LRC) and consists of first degree relatives of Stanford University employees who were selected either as a 2% random sample or were identified through a high lipid value. The variables are all standardized using three methods of age and sex adjustment based on two reference populations. The analysis and interpretations are based on the following statistics and indices: 1) the major gene index (MGI (alpha); 2) two measures of correlations between the midparental value and offspring (MPCC); and 3) the offspring between parent functions (OBP (beta). Consistent with a number of other studies, the results support that height shows multifactorial inheritance while height is principally under the influence of non-genetic environmental factors. In contrast to the random families, the male children of the probands who were selected due to their high lipid values exhibit height measurements which appear to involve environmental components or some major gene concomitants. The difference between the random and high lipid families is supported by all three statistical methods.
On the Applicability of Communication Theory to Industrial Markets

Patterns of influence within a given buying organization and among the various companies in an industry make industrial markets complex targets for marketing effort. Efficient marketing strategies build on these patterns of influence or, at least, do not seriously challenge these established relationships. It is therefore surprising that marketing literature has few studies of influence processes in industrial markets. With appropriate modifications, a broadly defined communication theory may help to identify, to structure, and to analyze patterns of influence in industrial markets. This article considers
Calculation and evaluation of the gibbs energies of formation of Cr 3 C 2 , Cr 7 C 3 , and Cr 23 C 6

A thermodynamic analysis of chemical composition data for a series of iron alloys containing chromium and carbon has been completed. These data were obtained from literature compilations for alloys equilibrated for extended times at 700 °C under neutral atmospheres. The results of this analysis, when supplemented with thermochemical data from the literature, permitted the calculation of the standard Gibbs energies of formation for the chromium carbides Cr7C3 and Cr23C6 over the range 600 to 1000 °C. These standard Gibbs energies were compared to data for these carbides from other sources. Available Gibbs energy data for the third pure chromium carbide, Cr3C2, were also evaluated. For each of these three compounds, a separation of the values for the Gibbs energy of formation into two distinct groups was observed. Each of these groups can be classed according to the nature of the experimental study used, whether it be a high temperature solid-gas equilibration involving a system of a carbide-chromic oxide-carbon (or chromium) with carbon monoxide, on one hand, or a series of investigations concerned mainly with electrolytic cell measurements, plus the work on which the present study is based. It is suggested that the differences in the Gibbs energies of formation for the respective carbides are associated with 1) the nonstoichiometric nature of these carbides and 2) possible dissolution of oxygen in the carbides during the equilibration studies.
The cholesterol content of the hair of the albino rat.

The data reported herein represent a preliminary study of the lipoids in the hair of the albino rat.The hair of young normal rats was found to contain 4.5 per cent total lipoids. The total cholesterol content of these lipoids, determined by the digitonin method, was found to be 11.9 per cent, and of this amount 80 per cent consisted of free cholesterol and 20 per cent of combined cholesterol. The amount of lecithin present was calculated from the phosphorus content of the lipoids and amounted to 0.8 per cent of the total lipoids. In a previous communication1 attention was called to the fact that the lipoids of the human skin contained as much as 20 per cent of total cholesterol. Work is now in progress which will determine the nature of the lipoids in the hair of rachitic rats.
A NUMERICAL INVESTIGATION OF FLAME LIFTOFF AND STABILIZATION

*† The effects of both fuel and air stream dilution on the liftoff, stabilization, and blowout characteristics of laminar nonpremixed flames (NPFs) and partially premixed flames (PPFs) are investigated. Lifted methane-air flames were established in axisymmetric coflowing jets. Because of its flame suppression characteristics CO2 is used as a diluent. A time-accurate, implicit algorithm that uses a detailed description of the chemistry and includes radiation effects is used for the simulations. The predictions are validated using measurements of the reaction zone topologies and liftoff heights of both NPF and PPF. While an undiluted PPF is stabilized at the burner rim, characterized by significant radical destruction and heat loss to the burner, the corresponding undiluted NPF is lifted and stabilized in a low-velocity region extending from the wake of the burner. Detailed comparison of diluted NPF with PPF reveals that the base structures of both the flames are similar and exhibit a double flame structure in the near-field region, where the flame stabilization depends on a balance between the reaction rate and the scalar dissipation rate. As dilution is increased, the flames become weaker, move downstream along the stoichiometric mixture fraction line, and stabilize at a location where they can find a local flowfield that has a lower scalar dissipation rate. Further increase in dilution moves the flames further downstream into the far-field region, where the fuel and air stream diluted NPF and PPF exhibit a triple flame structure, and the flame stabilization mechanism also involves a balance between the triple flame speed and local flow velocity. Simulations show that with fuel stream dilution, PPFs stabilize at a higher liftoff height and blowout at a lower CO2 dilution compared to NPFs. In contrast, with air stream dilution, NPFs move to a higher liftoff height and blowout at a lower CO2 dilution compared to PPFs. The observed effects of partial premixing, and fuel stream and air stream dilution on flame liftoff and blowout can be explained using the existing flame stabilization theories.
Seamless Link-Level Redundancy to Improve Reliability of Industrial Wi-Fi Networks

The adoption of wireless communications and, in particular, Wi-Fi, at the lowest level of the factory automation hierarchy has not increased as fast as expected so far, mainly because of serious issues concerning determinism. Actually, besides the random access scheme, disturbance and interference prevent reliable communication over the air and, as a matter of fact, make wireless networks unable to support distributed real-time control applications properly. Several papers recently appearing in literature suggest that diversity could be leveraged to overcome this limitation effectively. In this paper, a reference architecture is introduced, which describes how seamless link-level redundancy can be applied to Wi-Fi. The framework is general enough to serve as a basis for future protocol enhancements, and also includes two optimizations aimed at improving the quality of wireless communication by avoiding unnecessary replicated transmissions. Some relevant solutions have been analyzed by means of a thorough simulation campaign, in order to highlight their benefits when compared with conventional Wi-Fi. Results show that both packet losses and network latencies improve noticeably.
Nitrogen uptake : Apparent pattern during old field succession in Southeastern U.S.

Nitrogen uptake from applied nutrient solutions was evaluated in two old fields, in a pine plantation, and in a hardwood stand, to test the idea that plant communities become more efficient trappers and retainers of plant nutrients during succession. Uptake was estimated as the difference between nutrient concentrations in water collected from beneath soil profiles with and without roots by lysimeters within each successional stage. Results suggest that nitrate uptake decreased while ammonia uptake increased with succession. This apparent shift from a nitrate to an ammonia nitrogen economy during succession has been reported by other workers and is evolutionarily significant as an energy, nitrogen, and cation saving mechanism.
An analysis on the urban heat island effect using radiosonde profiles and Landsat imagery with ground meteorological data in South Florida

Decades-long effects of drainage and development in south Florida that began in early to mid-20th century have resulted in the loss of natural forested and rangelands, and expansion of agricultural and urban areas. This has brought a change in the thermalscape of the surrounding areas. Surface and atmospheric surface-layers become drier and warmer in anthropogenic land covers compared to natural ones, introducing an effect called the urban heat island. This study aims to analyse the spatial and temporal existence of the urban heat island on land surface and near-surface atmosphere during summer using land-use/land-cover data, surface-based weather station records, radiosonde profiles, and Landsat-5 Thematic Mapper images captured between 1970 and 2012 in south Florida. Urban cover increased by about 10% from 1974 to 2011. The station-based urban–rural temperature difference Tu-r is about 4°C over the entire area of south Florida and Landsat-derived surface temperature difference is about 3°C in the Landsat-covered area. They both show temporal increase throughout the period at a rate higher than the rate of increase of global average temperature. A decreasing near-surface diurnal temperature range of about ‒1°C p = 0.005 and increased lifting condensation level >20 m were detected from the Miami radiosonde. Satisfactory validation results of surface and near-surface temperature Nash–Sutcliffe coefficient = 0.70, coefficient of determination = 0.79 from the eastern urban stations further substantiate the findings on urban heat islands explored by the observed data.
Stroke Death in Sichuan Province,2002-2011

Objective To understand the epidemiological characteristics of the deaths caused by stroke in Sichuan and provide basis for prevention and control measures.Methods Descriptive epidemic analysis was conducted on the surveillance data of stroke deaths in Sichuan from 2002 to 2011 with specific death cause statistic software.Results The number of stroke deaths ranked the second of all disease-caused deaths and accounted for 18.45%.The crude death rate was 113.61/105,and the standardized death rate was 94.51/105.More deaths occurred in males and aged more 45.The death rate increased with age,and the annual death rate increased by 3.50% over time.Conclusion The deaths caused by stroke are rapidly increasing in Sichuan.It is necessary to conduct comprehensive prevention and control measures to reduce the incidence and fatality of stroke.
Performance Analysis of ARQ Based on Discrete-time Queue

Based on Automatic Repeat request(ARQ) operation mechanism,the discrete-time Geom/G/1 queue model with setup is built. With the method of embedded Markov chain,some queue system performance measurements that the length of queue under steady state,waiting time,busy period and busy circle are derived. The formula of the average frame response time,channel utility ratio and system throughput are presented. To explain these formulas,a numerical example is given and a simulation experiment is performed with Matlab.
Cockroach Monitoring and Exploration for its Control in Shouguang City from 2007 to 2009

Objective To further understand the cockroach population,density distribution and seasonal fluctuation regular pattern in Shouguang City,and to provide scientific basis for controlling and preventing cockroach-vectored diseases.Methods In accordance with the Guide for National Vector Biomoni-toring Program(Trial),we conducted continuous dynamic monitoring on the cockroaches in Shouguang City and suburban areas from 2007 to 2009.Results For the year of 2007,2008 and 2009,the averaged density of cockroaches were 0.08/unit,0.09/unit and 0.11/unit,respectively.The main category were the German cockroaches which reached its greatest density between May and October and were primarily distributed in agricultural markets and hotels.Conclusion There was an increasing tendency of cockroach distribution density in Shouguang city from 2007 to 2009.The main seasons performing pre-vention and control should be June through September period,and the main areas should be agricultural markets and hotels.Moreover,a integrated control strategy should be conducted focusing on the living habits of German cockroaches
The Effects of Categorization on Perceptual Judgment are Robust across Different Assessment Tasks

Learned visual categorical perception (CP) effects were assessed using three different measures (similarity rating, same-different judgment, and an XAB task) and two sets of stimuli differing in discriminability and varying on one category-relevant and one category-irrelevant dimension. Participant scores were converted to a common scale to allow assessment method to serve as an independent variable. Two different analyses using the Bayes Factor approach produced patterns of results consistent with learned CP effects: compared to a control group, participants trained on the category distinction could better discriminate between-category pairs of stimuli and were more sensitive to the category-relevant dimension. In addition, performance was better in general for the more highly discriminable stimuli, but stimulus discriminability did not influence the pattern of observed CP effects. Furthermore, these results were consistent regardless of how performance was assessed. This suggests that, for these methods at least, learned CP effects are robust across substantially different performance measures. Four different kinds of learned CP effects are reported in the literature singly or in combination: greater sensitivity between categories, reduced sensitivity within categories, increased sensitivity to category-relevant dimensions, and decreased sensitivity to category-irrelevant dimensions. The results of the current study suggest that the cause of these different patterns of CP effects is not due to either stimulus discriminability or assessment task. Other possible causes of the differences in reported CP findings are discussed.
Consumers’ perceived post purchase risk in luxury services

Abstract The objectives of this study are to: (1) define the concept of perceived post purchase (3P) luxury risk and (2) develop and validate a psychometrically sound 3P Luxury Risk Scale. A qualitative study and two field studies were conducted to develop and test the scale, and to examine the predictive validity of 3P luxury risk in a nomological network of word-of-mouth (WOM). The survey data is gathered from 333 actual customers of five golf clubs. Integrating structural equation modeling with propensity score analysis, the results of Study 1 reveal that 12 items adequately capture the dimensions of 3P luxury risk. After controlling for framing effects, the results of Study 2 indicate that all of the dimensions of 3P luxury risk negatively influence WOM. This article attempts to shed a new light on the realm of luxury risk studies incorporating normative and behavioral decision-making approaches.
Measuring the symptom burden of head and neck cancer patients undergoing concurrent chemotherapy and radiation therapy using area under the curve

6067 Background: Patients with head and neck cancer (HNC) experience a significant treatment-related symptom burden during therapy that presents management challenges for both patients and treatmen...
Improving Global Gross Primary Productivity Estimates by Computing Optimum Light Use Efficiencies Using Flux Tower Data

In the Light Use Efficiency (LUE) approach of estimating the Gross Primary Productivity (GPP), plant productivity is linearly related to Absorbed Photosynthetically Active Radiation (APAR) assuming that plants absorb and convert solar energy into biomass within a maximum LUE (LUEmax) rate, which is assumed to vary conservatively within a given biome type. However, it has been shown that photosynthetic efficiency can vary within biomes. In this study, we used 149 global CO2 flux towers to derive the Optimum LUE (LUEopt) under prevailing climate conditions for each tower location, stratified according to model training and test sites. Unlike LUEmax, LUEopt varies according to heterogeneous landscape characteristics and species traits. The LUEopt data showed large spatial variability within and between biome types, so that a simple biome classification explained only 29% of LUEopt variability over 95 global tower training sites. The use of explanatory variables in a mixed effect regression model explained 62.2 % of the spatial variability in tower LUEopt data. The resulting regression model was used for global extrapolation of the LUEopt data and GPP estimation. The GPP estimated using the new LUEopt map showed significant improvement relative to global tower data, including a 15% R2 increase and 34% RMSE reduction relative to baseline GPP calculations derived from biome specific LUEmax constants. The new global LUEopt map is expected to improve the performance of LUE based GPP algorithms for better assessment and monitoring of global terrestrial productivity and carbon dynamics.
EPR and IR Studies of Surface Nitrosyl Complexes

Epr and ir studies provide convincing evidence that nitric oxide forms surface complexes with metal ions. The nature of the bonding and the stability of the complexes vary greatly from one metal ion to another. In complexes with Ni2+, Cr2+, and Fe2+ the NO mostly becomes cationic in character, and the epr spectra suggest a formal reduction of the metal ion. Such complexes are moderately stable at 25°C with respect to the loss of the NO ligand. Weak covalent bonding is observed when NO complexes with Cu+ or Ag+; however, a complex attributed to [Ag(I)2NO]2+ is more stable. Nitrosyl complexes formed with Co2+ ions in Y-type zeolites are particularly interesting since it is possible to alter the anionic character of the NO group by the addition of electron — donating ligands such as NH3. Three types of complexes may be formed, which have been described as [Co(II) (NO)2]2+, [Co(II) NH3 (NO)2]2+, and [Co(III) (NH3) 5NO]2+, based upon their infrared spectra. In the latter complex the anionic nitrosyl group reacts both with the ammonia ligands and with gas phase nitric oxide. The reaction with NH3 produces N2 and H2O, whereas the reaction with excess NO yields N2O and the nitro complex, [Co(NH3) 5NO2]2+.