cssi/SciSciGPT-SciSciNet huggingface dataset:
Cell density dependent regulation of phenylalanine hydroxylase activity in hepatoma cells. Evidence for both an active and inactive enzyme form.

Abstract The cell density dependent regulation of phenylalanine hydroxylase activity in Reuber hepatoma (H4) cells growing in monolayer culture has been examined in detail. We found that 48 h or more after subculture phenylalanine hydroxylase activity in the cells is an exponential function of cell density (cells/cm2). No discontinuity in the relationship is seen with the formation of a confluent monolayer. A rapid loss or a rapid gain in enzyme activity in the cells is observed after diluting or concentrating the cell cultures. The two processes appear qualitatively different. The loss in activity is a first order process which starts at the time of subculture with the rate of loss dependent on the density of subculture. The gain in activity begins 6–8 h after subculture to a higher density; it can be blocked by cycloheximide and has a maximum rate of increase that is about 10% of the maximum rate of loss of activity. Using immunochemical procedures, we found the same amount of phenylalanine hydroxylase associated antigen in Reuber cells from low density as from high density cultures, over a range of phenylalanine hydroxylase specific activities from 0.2 to 4.2. After concentrating cells to a higher density, no increase in enzyme antigen was observed, despite a several-fold increase in enzyme activity and a requirement for protein synthesis during the process. These observations imply the presence of an active and inactive phenylalanine hydroxylase with the relative amounts of each determined by the cell density. The effects of db-cAMP are discussed. Evidence is presented here that the hydrocortisone stimulation of phenylalanine hydroxylase activity works through a different mechanism than the cell density dependent process.
Grazing catfish, fishing birds, and attached algae in a Panamanian stream

In streams where algivorous fishes abound, striking variation of attached algae often develops along depth gradients, with bands of high standing crops in shallow water ( 20 cm) water, algae were rapidly consumed by grazing catfish. Catfish were removed from three stream pools and left in place in three control pools. Ten days after catfish removal, algal standing crops in deep and shallow areas of removal pools were similar, while algal standing crops were higher in shallow than in deep areas of control pools. Catfish were exposed to fishing birds in open-topped enclosures. In one of three series of these pens, most catfish in shallow pens (10 and 20 cm) disappeared after 14 days, while catfish in deeper pens (30 and 50 cm) did not. Other groups of catfish which were caged 8 days showed differences in behavior depending on whether they had been fed or starved. After their release into their home pool, starved catfish spent more time feeding than did fed catfish. Despite their apparently increased hunger levels, starved catfish did not venture into shallow water to obtain algae. These results support the view that predator induced avoidance by grazers of certain areas can produce spatial pattern in the flora of flowing water communities.
Communication Complexity and Energy Efficient Consensus Algorithm

Abstract In this paper, we analyze distributed average consensus algorithms, both deterministic and gossip based, with respect to a new metric related to the energy cost of communication among agents. We first introduce a new notion of communication complexity as a metric to assess the energy efficiency properties of consensus algorithms. We provide explicit formulas to compute the communication complexity of deterministic algorithms and gossip based algorithms depending on different stopping criteria. We also show that the gossip based algorithms have less communication complexity than the deterministic counterparts under mild conditions, usually satisfied by a large number of networks. We also show that the gossip algorithm with minimum communication complexity can be effectively computed as the solution of a convex optimization problem.
Delay Test: The Next Frontier for LSSD Test Systems

Delay testing, as opposed to static testing introduces the parameter of time as a new variable. Time impacts the way defects manifest themselves and are modeled as faults, as well as how defect sizes and system timing statistics interact with tester timing constraints in the detection of causes for dynamic system malfunctions. This paper briefly discusses some of the issues that had to be addressed in the development of a comprehensive system for delay testing in a Level Sensitive Scan Design environment.
Using high-fidelity emergency simulation with large groups of preclinical medical students in a basic science course

Background: High-fidelity patient simulation is often used to teach clinical patient management and decision-making with small groups. This pilot project determined feasibility for large-group educational presentations using simulation for preclinical basic science courses.Methods: We developed an emergency patient simulation encounter illustrating basic neuroscience concepts. Physician actors interacted with a high-fidelity simulated patient mannequin in a lecture hall. First and second year medical students were active participants in the 90 minute live event in large groups. Digital video was recorded and written feedback was obtained from participants.Results: The simulation was presented four times to a total of 202 students. Video review demonstrated extensive interaction within the large groups. Case management discussions included basic science topics, autonomic pathways, and neuropharmacology. Student feedback revealed 98% rated the correlation to basic science concepts as very good or outstandin...
Identification of transcripts generated during the response of resistant Biomphalaria glabrata to Schistosoma mansoni infection using suppression subtractive hybridization

Suppression subtractive hybridization (SSH) was used to construct a complementary DNA library enriched for transcripts more abundantly expressed in the resistant BS90 strain of Biomphalaria glabrata at 12 hr postinfection with Schistosoma mansoni as compared with the susceptible M-line strain under the same circumstances. One hundred and twelve clones of the library were sequenced, yielding 88 unique SSH–expressed sequence tags (ESTs). Differential expression screening indicated that 22 of the 88 unique transcripts were strong candidates for differential expression in the BS90 strain relative to the M-line strain. Analysis of a subset of 4 transcripts using quantitative reverse transcriptase–polymerase chain reaction (qPCR) substantially supports the patterns obtained using the differential expression screen. Furthermore, the qPCR results revealed that gene upregulation in resistant snails, downregulation in susceptible snails, and differences in constitutive gene expression can all account for differenti...
Positive Receptor Feedback during Lineage Commitment Can Generate Ultrasensitivity to Ligand and Confer Robustness to a Bistable Switch

Cytokines and lineage-specific transcription factors are critical molecular effectors for terminal differentiation during hematopoiesis. Intrinsic transcription factor activity is often believed to drive commitment and differentiation, whereas cytokine receptor signals have been implicated in the regulation of cell proliferation, survival, and differentiation. In erythropoiesis, recent experimental findings provide direct evidence that erythropoietin (Epo) can generate commitment cues via the erythropoietin receptor (EpoR); specifically, EpoR signaling leads to activation of the transcription factor GATA-1, which then triggers transcription of erythrocyte-specific genes. In particular, activated GATA-1 induces two positive feedback loops in the system through the enhanced expression of both inactive GATA-1 and EpoR, the latter of which is externally regulatable by Epo. Based upon this network architecture, we present a mathematical model of GATA-1 activation by EpoR, which bidirectionally links a lineage-specific receptor and transcription factor. Our deterministic model offers insight into stimulus-response relationships between Epo and several downstream effectors. In addition to the survival signals that EpoR provides, steady-state analysis of our model suggests that receptor upregulation during lineage commitment can also generate ultrasensitivity to Epo and bistability in GATA-1 activity. These system-level properties can induce a switch-like characteristic during differentiation and provide robustness to the mature state. The topology also suggests a novel mechanism for achieving robust bistability in a purely deterministic manner without molecular cooperativity. The analytical solution of a generalized, minimal model is provided and the significance of each of the two positive feedback loops is elucidated through bifurcation analysis. This network topology, or variations thereof, may link other receptor-transcription factor pairs and may therefore be of general relevance in cellular decision-making.
Coding strategies for a class of decentralized control problems with limited communication

We propose a large class of decentralized control problems with non-classical information structure for which a coding strategy is optimal. This class is a generalized version of the hats problem with statistically dependent hat colors where implicit communication via action is allowed. We propose a sufficient condition on the joint distribution of the hat colors which guarantees the optimality of a binary sum coding strategy. We explore the connection between this version of the hats problem and hypercube graph theory, and use that to show that verifying our proposed sufficient condition is computationally tractable.
Potential use of FDG-PET scan after induction chemotherapy in surgically staged IIIa–N2 non-small-cell lung cancer: A prospective pilot study

Summary Background Clearance of viable tumour cells in mediastinal lymph nodes (MLN) by induction chemotherapy (IC) – so-called MLN downstaging – is an important aspect of combined-modality treatment of N2-NSCLC. Reassessment of MLN after IC by CT is far from accurate, while re-mediastinoscopy is often technically difficult. Based on our previous results with FDG-PET in the initial staging of N2 disease, we investigated whether PET after IC could be helpful in predicting MLN downstaging and therapeutic outcome. Patients and methods Patients underwent a first PET before IC. After three cycles of platinum-based IC, a second PET was performed before locoregional therapy, either surgery or radiotherapy. PET results were correlated with pathology of the MLN when available, and with survival. Results Fifteen surgically staged N2-NSCLC patients were prospectively included. Locoregional therapy after IC consisted of surgery in nine and radiotherapy in six. Correlation with pathology of the nine resection specimens revealed that the accuracy of PET in predicting MLN downstaging was 100% (six true negatives; three true positives), whereas for CT it was only 67% (two false pos; one false neg). Reassessment with PET after IC was correlated with the outcome after the entire combined modality treatment. Survival was significantly better in patients with mediastinal clearance (P = 0.01) or with a greater than 50% decrease in the Standardised Uptake Value (SUV) of the primary tumour (P = 0.03) after IC. Conclusions Mediastinal PET after IC accurately assesses pathologic MLN downstaging in N2-NSCLC. The data suggest a possible correlation of early survival with mediastinal clearance and an important decrease of SUV in the primary tumour. Confirmation of these preliminary findings would establish PET as a useful non-invasive tool to select patients for intensive locoregional treatment after IC.
Yoda: An Accurate and Scalable Web-Based Recommendation System

Recommendation systems are applied to personalize and customize the Web environment. We have developed a recommendation system, termed Yoda, that is designed to support large-scale Web-based applications requiring highly accurate recommendations in real-time. With Yoda, we introduce a hybrid approach that combines collaborative filtering (CF) and content-based querying to achieve higher accuracy. Yoda is structured as a tunable model that is trained off-line and employed for real-time recommendation on-line. The on-line process benefits from an optimized aggregation function with low complexity that allows realtime weighted aggregation of the soft classification of active users to predefined recommendation sets. Leveraging on localized distribution of the recommendable items, the same aggregation function is further optimized for the off-line process to reduce the time complexity of constructing the pre-defined recommendation sets of the model. To make the off-line process scalable furthermore, we also propose a filtering mechanism, FLSH, that extends the Locality Sensitive Hashing technique by incorporating a novel distance measure that satisfies specific requirements of our application. Our end-to-end experiments show while Yoda's complexity is low and remains constant as the number of users and/or items grow, its accuracy surpasses that of the basic nearest-neighbor method by a wide margin (in most cases more than 100%).
On rate-k/2k self-dual convolutional codes

A class of rate-k/2k self-dual convolutional codes is defined, which includes, for instance, the Golay convolutional code. It is shown that codes in this class are not asymptotically catastrophic in the sense defined by Hemmati and Costello (1980).
Laboratory diagnosis of dysfibrinogenemia.

Abstract Dysfibrinogenemia is a coagulation disorder caused by a variety of structural abnormalities in the fibrinogen molecule that result in abnormal fibrinogen function. It can be inherited or a...
Time-dependent density-functional theory method in the electron nuclear dynamics framework

Abstract A time-dependent density-functional theory (DFT) dynamics method in the electron nuclear dynamics (END) framework is presented. This time-dependent variational method treats simultaneously the nuclei and electrons of a system without utilizing predetermined potential energy surfaces. Like the simplest-level END, this method adopts a classical-mechanics description for the nuclei and a Thouless single-determinantal representation for the electrons. However, the electronic description is now expressed in a Kohn–Sham DFT form that provides electron correlation effects absent in the simplest-level END. Current implementation of this method employs the adiabatic approximation in the exchange–correlation action and potential. Simulations of molecular vibrations and proton–molecule reactions attest to the accuracy of the present method.
New experimental data for the system CaO-MgO-SiO2-H2O and a synthesis of inferred phase relations

Abstract Subsolidus and vapor-saturated liquidus phase relations for a portion of the system CaO-MgO-SiO 2 -H 2 O, as inferred from experimental data for the composition regions CaMgSi 2 O 6 -Mg 2 SiO 4 -SiO 2 -H 2 O and CaMgSi 2 O 6 -Mg 2 SiO 4 -Ca 3 MgSi 2 O 8 (merwinite)-H 2 O, are presented in pressure-temperature projection. Sixteen invariant points and 39 univariant reactions are defined on the basis of the 1 atm and 10 kbar (vapor-saturated) liquidus diagrams. Lack of experimental control over many of the reactions makes the depicted relations schematic in part. An invariant point involving orthoenstatite, protoenstatite, pigeonite, and diopside (all solid solutions) occurs at low pressure (probably between 1 and 2 kbar). At pressures below this invariant point, orthoenstatite breaks down at high temperature to the assemblage diopside + protoenstatite; with increasing temperature, the latter assemblage reacts to form pigeonite. At pressures above the invariant point, pigeonite forms according to the reaction diopside + orthoenstatite = pigeonite, and the assemblage diopside + protoenstatite is not stable. At 1 atm, both pigeonite and protoenstatite occur as primary liquidus phases, but at pressures above 6–7 kbar orthoenstatite is the only Ca-poor pyroxene polymorph which appears on the vapor-saturated liquidus surface. At pressures above approximately 10.8 kbar, only diopside, forsterite, and merwinite occur as primary liquidus phases in the system CaMgSi 2 O 6 -Mg 2 SiO 4 -Ca 3 MgSi 2 O 8 -H 2 O, in the presence of an aqueous vapor phase. At pressures between 1 atm and 10.2 kbar, both akermanite and monticellite also occur as primary liquidus phases. Comparison of the 1 atm and 10 kbar vapor-saturated liquidus diagrams suggests that melilite basalt bears a low pressure, or shallow depth, relationship to monticellite-bearing ultrabasites.
Transitional Spaces: Blurring the Line Between Interior and Exterior

This paper examines the transition spaces for homes between inside and outside designed by architects during the early twentieth century in the United States. Beginning in the late nineteenth century, the plan book became a readily available option for those wishing to build their own home in the U.S. Following a shortage of single-family houses after World War I, the design of small, single-family houses were distributed primarily through the plan book vehicle. One such plan book-producing group was the Architects' Small House Service Bureau (ASHSB). The bureau was composed entirely of registered architects and produced multiple folios of small house plans between 1914 and 1942. This paper focuses specifically on the relationship between the interior spaces and outdoors through the use of loggias, pergolas, sun porches, bay windows and other devices. The ASHSB was unique in that they promoted customization of their mass-produced house plan designs to each individual site. Thus, unlike many other plan book creators, ASHSB members determined that the relationship to the site was important to the overall design and the use of these transitional indoor/outdoor spaces, a necessity. The plans designed by ASHSB members fell into one of three sizes ” four-room, five-room or six-room plan types. The maximum number of principal rooms was six. All small house designs were presented within a rendered landscaped setting showing trees, bushes, benches and other landscaping features. At least one of the following -- porticoes, porches, dormers, bay windows, picture windows, port coheres, and sun porches”was used in every design produced by the ASHSB architect members. This work examines the range and type of spaces as well as the written recommendations and specifications that accompanied plan sets distributed by the ASHSB across the U.S and Canada during the early twentieth century.
Parolee Recidivism in California: The Effect of Neighborhood Context and Social Service Agency Characteristics

We studied a sample of reentering parolees in California in 2005–2006 to examine whether the social structural context of the census tract, as well as nearby tracts, along with the relative physical closeness of social service providers affects serious recidivism resulting in imprisonment. We found that a 1 standard deviation increase in the presence of nearby social service providers (within 2 miles) decreases the likelihood of recidivating 41 percent and that this protective effect was particularly strong for African American parolees. This protective effect was diminished by overtaxed services (as proxied by potential demand). We found that higher concentrated disadvantage and social disorder (as measured by bar and liquor store capacity) in the tract increases recidivism and that higher levels of disadvantage and disorder in nearby tracts increase recidivism. A 1 standard deviation increase in the concentrated disadvantage of the focal neighborhood and the surrounding neighborhoods increases the likelihood of recidivating by 26 percent. The findings suggest that the social context to which parolees return (both in their own neighborhood and in nearby neighborhoods), as well as the geographic accessibility of social service agencies, play important roles in their successful reintegration.
p53 regulates Stat3 phosphorylation and DNA binding activity in human prostate cancer cells expressing constitutively active Stat3

Constitutive activation of the signal transducer and activator of transcription 3 (Stat3) and mutation of the p53 are both commonly detected in human prostate cancer cells. We sought to investigate whether there is functional regulation of Stat3 by wild-type (wt) p53. Our results demonstrate that expression of wt p53 but not mutant p53 significantly reduced tyrosine phosphorylation of Stat3 and inhibited Stat3 DNA binding activity in both DU145 and Tsu prostate cancer cell lines that express constitutively active Stat3. Expression of the p53 downstream target, p21WAF-1, did not have any inhibitory effect on Stat3 phosphorylation. Wt p53 but not p21WAF-1 induced dramatic apoptosis in these prostate cancer cells. Expression of wt p53 did not cause a reduction of phosphorylation-independent Stat3 protein and reduction of phosphorylation of three unrelated protein kinases, ERK1, ERK2 (ERK1/2), and AKT. Interestingly, p53-dependent apoptosis occurred in the presence of high levels of phosphorylated AKT and ERK1/2 in both DU145 and Tsu prostate cancer cells. Further, we evaluated a series of established human prostate, breast, and ovarian cancer cell lines and found that all cancer cell lines expressing constitutively active Stat3, only harbor mutated or deleted p53. One implication of these results is that the anti-proliferative activities of p53 may not be compatible with the constitutive Stat3 signal in cancer cells.
Influence of herbaceous riparian buffers on physical habitat, water chemistry, and stream communities within channelized agricultural headwater streams

a b s t r a c t Herbaceous riparian buffers (CP 21 grass filter strips) are a widely used agricultural conservation practice in the United States for reducing nutrient, pesticide, and sediment loadings to agricultural streams. The ecological impacts of herbaceous riparian buffers on the channelized agricultural headwater streams that are common throughout the midwestern United States have not been evaluated. We sampled riparian habitat, geomorphology, instream habitat, water chemistry, fishes, and amphibians for 4 years from three channelized agricultural headwater streams without herbaceous riparian buffers and three channelized streams with herbaceous riparian buffers in central Ohio. Only seven of 55 response variables exhibited differences between buffer types. Riparian widths were greater in channelized headwater streams with herbaceous riparian buffers than streams without herbaceous riparian buffers. Percent insectivores and minnows were greater in channelized streams without herbaceous riparian buffers than streams with herbaceous riparian buffers. Percent clay, turbidity, specific conductance, and pH differed between buffer types only during one sampling period. No differences in geomorphology and amphibian communities occurred between buffer types. Our results suggest channelized agricultural headwater streams with and without herbaceous riparian buffers are similar physically, chemically, and biologically. Installation of herbaceous riparian buffers alone adjacent to channelized agricultural headwater streams in central Ohio and other parts of the midwestern United States may only provide limited environmental benefits for these stream ecosystems in the first 4–6 years after establishment. Alternative implementation designs combining the use of herbaceous riparian buffers with other practices capable of altering nutrient and pesticide loads, riparian hydrology, and instream habitat are needed. Published by Elsevier B.V.
Simultaneous robust tracking and disturbance rejection with stable plants

The robust asymptotic tracking and disturbance rejection problem is studied with a two-output plant and a two-input compensator, with disturbances entering directly into the plant and in the two junctions between plant and compensator. Two situations are considered with respect to that part of the plant which is connected to the compensator's output, namely, when one of its block matrices is fixed while the other is perturbed arbitrarily and when the two block matrices are related by another (fixed) block matrix. Necessary and sufficient conditions are obtained for the compensators which solve the problems. Conditions for the solvability of the general problems are obtained as well. >
Investigation of the use of X-ray CT images for attenuation compensation in SPECT

This study investigates the general use of single-beam X-ray computed tomography (CT) images for generating attenuation maps for compensation of photon attenuation in SPECT images. A 3D mathematical thorax phantom is used to simulate both emission and transmission projection data for monoenergetic (radionuclide) and polyenergetic (X-ray) sources. Polyenergetic transmission projection data are simulated for a standard X-ray spectrum and fan-beam geometry. The projection data are reconstructed using filtered backprojection to form an X-ray CT image which is then scaled to produce an estimate of the attenuation map at the energy of the emission radionuclide. Emission projection data are simulated for a fan-beam geometry at the energies of /sup 201/Tl and /sup 99m/Tc, two radionuclides commonly used in cardiac SPECT. Detector response and scatter are not included in the model. Noiseless, emission projection data are iteratively reconstructed using the ML-EM algorithm with nonuniform attenuation compensation and attenuation maps derived from both the simulated X-ray CT image and from a simulated monoenergetic transmission CT image. The attenuation maps generated from the X-ray CT images accurately estimate the attenuation coefficient for muscle and lung tissues, but not for bone tissues, which show error in the attenuation coefficient of 21-42% for spinal bone and 34-58% for rib bone. However, despite the inaccurate estimate of bone attenuation, the reconstructed SPECT images provide estimates of myocardial radioactivity concentration to within 9% and show few artifacts. >
Intentional maps in posterior parietal cortex

The posterior parietal cortex (PPC), historically believed to be a sensory structure, is now viewed as an area important for sensory-motor integration. Among its functions is the forming of intentions, that is, high-level cognitive plans for movement. There is a map of intentions within the PPC, with different subregions dedicated to the planning of eye movements, reaching movements, and grasping movements. These areas appear to be specialized for the multisensory integration and coordinate transformations required to convert sensory input to motor output. In several subregions of the PPC, these operations are facilitated by the use of a common distributed space representation that is independent of both sensory input and motor output. Attention and learning effects are also evident in the PPC. However, these effects may be general to cortex and operate in the PPC in the context of sensory-motor transformations.
Concentrate levels and Saccharomyces cerevisiae affect rumen fluid-associated bacteria numbers in dairy heifers

Abstract Total viable rumen bacteria counts through the use of colony-unit forming assays lack accuracy because they only include culturable bacteria capable of initiating cell division. Thus, bacterial counts can be underestimated. The use of fluorescent characteristics of cell membranes allows flow cytometry to enumerate and distinguish dead from live bacteria cells. The objective of this experiment was to investigate the viable and total ruminal bacteria counts when 3 levels of forage:concentrate in diets were fed at restricted levels with the addition of Saccharomyces cerevisiae (YC). Three cannulated post-pubertal Holstein heifers (age 18 ± 1.0 months) were fed corn silage (CS)-based diets in a 3-period (35 d) Latin square design. Heifers were fed the diets for 21 d with no yeast addition, followed by 14 d where yeast culture (YC) was added (1 g/kg as-fed basis); (Yea-Sacc 1026 , Alltech, Inc., Nicholasville, KY) . A low concentrate (LC) TMR (80% CS, 20% concentrate; 12.4% CP, 35% NDF), a medium concentrate (MC) TMR (60% CS, 40% concentrate; 12.3% CP. 28% NDF), and a high concentrate (HC) TMR (40% CS, 60% concentrate; 12.6% CP, 25% NDF), were fed once per day. Rumen fluid was sampled − 2, 0, 2, 4, 6, 8, 10, 12 h after feeding. Samples were immediately stained with fluorescent dyes using the Bac Light kit (Molecular Probes Inc., Eugene, OR) and analyzed with a Coulter XL-MCL single laser flow cytometer. Mean rumen viable bacteria counts linearly increased among treatments (4.96, 4.78, 6.73 × 10 11 ± 0.53 × 10 11 cells/ml; P = 0.02) for LC, MC and HC respectively, and YC addition increased number of viable bacteria cells ( P
Clustering: A neural network approach

Clustering is a fundamental data analysis method. It is widely used for pattern recognition, feature extraction, vector quantization (VQ), image segmentation, function approximation, and data mining. As an unsupervised classification technique, clustering identifies some inherent structures present in a set of objects based on a similarity measure. Clustering methods can be based on statistical model identification (McLachlan & Basford, 1988) or competitive learning. In this paper, we give a comprehensive overview of competitive learning based clustering methods. Importance is attached to a number of competitive learning based clustering neural networks such as the self-organizing map (SOM), the learning vector quantization (LVQ), the neural gas, and the ART model, and clustering algorithms such as the C-means, mountain/subtractive clustering, and fuzzy C-means (FCM) algorithms. Associated topics such as the under-utilization problem, fuzzy clustering, robust clustering, clustering based on non-Euclidean distance measures, supervised clustering, hierarchical clustering as well as cluster validity are also described. Two examples are given to demonstrate the use of the clustering methods.
The issue of spreading in multipath time-varying channels

The capacity of a multiple-access, time-varying but known multipath channel is considered in the presence of white Gaussian noise, a bandwidth constraint, and power constraints. It is assumed that the product of the time spread and the Doppler spread is small. The general case is specialized to particular cases such as flat fading and specular paths with fixed Doppler shifts. The results provide insight into questions of CDMA and orthogonal systems.
Symmetric Capacity of MIMO Downlink Channels

This paper studies the symmetric capacity of the MIMO downlink channel, which is defined to be the maximum rate that can be allocated to every receiver in the system. The symmetric capacity represents absolute fairness and is an important metric for slowly fading channels in which users have symmetric rate demands. An efficient and provably convergent algorithm for computing the symmetric capacity is proposed, and it is shown that a simple modification of the algorithm can be used to compute the minimum power required to meet given downlink rate demands. In addition, the difference between the symmetric and sum capacity, termed the fairness penalty, is studied. Exact analytical results for the fairness penalty at high SNR are provided for the 2 user downlink channel, and numerical results are given for channels with more users.
The Predictive Power of REIT Implied Volatility and Implied Idiosyncratic Volatility

Executive Summary. This paper examines the characteristics of real estate investment trust (REIT) equity options and the predictive power of ex ante risk measures obtained using option prices. In 1...
Transforming growth factor-β1-mediated cardiac fibrosis: potential role in HIV and HIV/antiretroviral therapy-linked cardiovascular disease.

HIV infection elevates the incidence of cardiovascular disease (CVD) independent of traditional risk factors. Autopsy series document cardiac inflammation and endomyocardial fibrosis in the HIV+ treatment naive, and gadolinium enhancement magnetic resonance imaging has identified prominent myocardial fibrosis in the majority of HIV+ individuals despite use of suppressive antiretroviral therapies (ART). The extent of such disease may correlate with specific ART regimens. For example, HIV-infected patients receiving ritonavir (RTV)-boosted protease inhibitors have the highest prevalence of CVD, and RTV-exposed rodents exhibit cardiac dysfunction coupled with cardiac and vascular fibrosis, independent of RTV-mediated lipid alterations. We recently showed that platelet transforming growth factor (TGF)-β1 is a key contributor to cardiac fibrosis in murine models. We hypothesize that in the HIV+/ART naive, cardiac fibrosis is a consequence of proinflammatory cytokine and/or ART-linked platelet activation with release of TGF-β1. Resultant TGF-β1/Smad signaling would promote collagen synthesis and organ fibrosis. We document these changes in a pilot immunohistochemical evaluation of cardiac tissue from two ART-naive pediatric AIDS patients. In terms of ART, we showed that RTV inhibits immunoproteasome degradation of TRAF6, a nuclear adapter signaling molecule critical to the regulation of proinflammatory cytokine signaling pathways involved in osteoclast differentiation and accelerated osteoporosis. We now present a model illustrating how RTV could similarly amplify TGF-β1 signaling in the promotion of cardiac fibrosis and accelerated CVD. Supportive clinical data correlate RTV use with elevation of NT-proBNP, a biomarker for CVD. We discuss potential interventions involving intrinsic modulators of inflammation and collagen degradation, including carbon monoxide-based therapeutics.
Evolutionary Market-Making: Economics vs. Finance

Markets are the basic institutions that lie at the heart of most economic and financial analyses. It is surprising, then, how very little work has been done on the existence of markets themselves. We investigate a model of non-sequential search, where potential buyers and sellers seek each other out. Specifically, we analyze the implications of two paradigms. The first is economic, involving Nash equilibrium and evolutionary game theory. The second is financial and is rooted in the no-arbitrage paradigm. It as well has an evolutionary interpretation. The contrast in the conditions that are required for equilibrium under these two paradigms illuminates some fundamentally different implications between economics and finance for the existence of markets and price dispersion.
A Subgrid Physics Model for Multi-Length Scale Thermal Analysis of MEMS

A subgrid physics model has been developed to analyze heat transfer in an integrated microsystem. By modeling the ‘multi-mode’ phonon scattering process in microstructures, the dominant microscale heat transfer mechanisms such as phonon scattering at thin-film boundaries and at grain boundaries will be captured. Thus a localized anisotropic thermal conductivity can be calculated for use in system analysis. With this new capability, a continuum thermal analysis tool can address thermal problems with multiple characteristic length scales. To demonstrate its capability, this subgrid physics model has been applied to simulate the thermal response of a microscale optical shutter. Result shows that internal material structures such as grain size can significantly change the thermal response of a microsystem.Copyright © 2005 by ASME
Symmetry properties of one-dimensional Fermi systems: Some nonperturbative results

Several exact results are proved for two models of one-dimensional conductors, a model with transfer cutoff and spin- and charge-carrying interactions and the usual backscattering model with a bandwidth cutoff. A set of Ward identities is derived which connects the three-point charge vertex parts with single-particle Green's functions. These are combined with a modified renormalization-group scheme to prove the scale invariance of the couplings between charge densities in the absence of umklapp processes. The Ward identities are also used for the computation of the correlation functions in the charge sector of the system. Then some canonical transformations are introduced which allow one to relate various response functions among themselves. From these relations the phase boundaries of the ground state can be established. It is shown that the transfer cutoff and the backscattering models have the same phase diagram.
Strict vs lenient criteria for elution testing: comparison of yields between two tertiary care medical centers.

In this study, 2 patient populations, using different elution strategies, were compared to evaluate eluate yields under more and less restrictive conditions. An informative eluate was defined as one in which an antibody that could be clinically significant was detected in the eluate but was not detectable in the plasma at the time of elution testing. The results for 160 direct antiglobulin tests (DATs) and 160 elution studies were evaluated in 71 patients at the adult hospital (lenient criteria). The results for 372 DATs and 43 elution studies were evaluated in 123 patients at the pediatric hospital (strict criteria). The yields from these eluates were 0.6% at the adult hospital (C antibody) vs 2.3% at the pediatric hospital (Jka antibody). Thus, the yield of information from eluate testing is low regardless of the stringency applied to testing. However, considering the cost and time required for testing, more stringent criteria are advised.
Conversion of phenytoin to reactive metabolites in rat liver microsomes.

The widely used anticonvulsant drug phenytoin (PHT) is primarily metabolized by aromatic hydroxylation. It is presumed that liver microsomal cytochrome(s) P450 catalyze the formation of an epoxide intermediate which gives rise to the major metabolite, 5-(4-hydroxyphenyl)-5- phenylhydantoin (4-HPPH)1,2 and a 3,4-dihydrodiol metabolite (DHD).3 In addition, PHT is converted to a catechol metabolite [5-(3,4-dihydroxyphenyl)-5-phenylhydantoin,CAT].4–7 CAT is formed from both 4-HPPH and DHD, although the predominate route is via 4-HPPH.8
Recurrence risk after resection of gastrointestinal stromal tumors: Size is not all that matters... the consequences of tumor rupture

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors that most commonly have activating mutations in KIT. Recurrence after complete resection remains a significant problem, and the ability to identify patients at high risk for recurrence would allow for selective use of adjuvant therapies such as imatinib in patients who may garner the most benefit. Initial staging systems stratified recurrence risk by tumor size and mitotic index, whereas subsequent staging systems also included tumor location. However, other clinical factors may influence prognosis and the risk for tumor recurrence after surgery. The purpose of this article is to highlight tumor rupture as an additional risk factor that should be considered when assessing for recurrence risk. Tumor rupture is associated with decreased survival and increased recurrence rates, but it is not universally included in current staging systems. Patients with ruptured GISTs may not meet the risk criteria elaborated in some current staging systems, yet these patients are at high risk for tumor recurrence and may benefit from adjuvant imatinib therapy. A fundamental understanding of all the risk factors for tumor recurrence, including tumor rupture, and appropriate consideration for adjuvant therapy through a multidisciplinary approach are requisite for the maximal prevention of disease recurrence.
Treatment of angina pectoris. Pharmacologic approaches.

In choosing a pharmacologic approach to the treatment of angina, the clinician will consider primarily the nitrites, beta-adrenergic blocking agents, and in special circumstances, digitalis. Experience with each of these is summarized.
David Oliver: Values statements aren't worth the paper.

In A Sceptic’s Medical Dictionary , the great Michael O’Donnell made mischievous fun of mission statements in the NHS, calling them “pious utterances trusts print below their expensively commissioned logo.”1 Values statements are close siblings; both are ubiquitous in health and social care.2 There’s nothing wrong with publicising your guiding values. But I suspect that most patients and families would prefer to experience these in the way they’re treated rather than see them written on leaflets, posters, and letterheads. Too often, statements are platitudinous—who could disagree with them? You can test …
Intellectual improvement based on cognitive skills’ development and promotion: An analysis

Cognitive development alludes to the understudy's comprehension of ideas and the capacity to think and reason. While dialect invigorates intellectual advancement, dialect complexity impacts subjective capacities. The capacity to cooperate with others while utilizing dialect offers understudies some assistance with developing psychological aptitudes. Understudies who are hard of hearing or deaf have the same ability for intellectual improvement as do understudies with ordinary hearing.
Low-cost functional plasticity of TRPV1 supports heat tolerance in squirrels and camels

The ability to sense heat is crucial for survival. Increased heat tolerance may prove beneficial by conferring the ability to inhabit otherwise prohibitive ecological niches. This phenomenon is widespread and is found in both large and small animals. For example, ground squirrels and camels can tolerate temperatures more than 40 °C better than many other mammalian species, yet a molecular mechanism subserving this ability is unclear. Transient receptor potential vanilloid 1 (TRPV1) is a polymodal ion channel involved in the detection of noxious thermal and chemical stimuli by primary afferents of the somatosensory system. Here, we show that thirteen-lined ground squirrels (Ictidomys tridecemlineatus) and Bactrian camels (Camelus ferus) express TRPV1 orthologs with dramatically reduced temperature sensitivity. The loss of sensitivity is restricted to temperature and does not affect capsaicin or acid responses, thereby maintaining a role for TRPV1 as a detector of noxious chemical cues. We show that heat sensitivity can be reengineered in both TRPV1 orthologs by a single amino acid substitution in the N-terminal ankyrin-repeat domain. Conversely, reciprocal mutations suppress heat sensitivity of rat TRPV1, supporting functional conservation of the residues. Our studies suggest that squirrels and camels co-opt a common molecular strategy to adapt to hot environments by suppressing the efficiency of TRPV1-mediated heat detection at the level of somatosensory neurons. Such adaptation is possible because of the remarkable functional flexibility of the TRPV1 molecule, which can undergo profound tuning at the minimal cost of a single amino acid change.
Single Phase Single-Stage Soft-SwitchingAc-to-Dc Series Resonant Converter

This paper presents a new single-phase, pulse width modulated (PWM), boost-integrated ac-to-dc full-bridge series resonant converter with high frequency transformer isolation. This converter uses a new gating scheme suitable for integrating boost converter and PWM dc-to-dc converter using a single control. Principle of operation and different operating modes are presented with analysis. Based on the analysis design example of a 1.7 kW, 420 V, 50 kHz ac-to-dc series resonant converter is presented to explain design procedure. PSPICE simulation results for the designed converter are presented. The results show soft-switching operation and low total harmonic distortion of this converter for a reasonably wide range of line and load.
Actual use of pocket-sized ultrasound devices for cardiovascular examination by trained physicians during a hospitalist rotation

Background : In actual clinical practice as opposed to published studies, the application of bedside ultrasound requires a perception of need, confidence in one’s skills, and convenience. Objective : As the frequency of ultrasound usage is evidence to its perceived value in patient care, we observed the pattern of autonomous use of a pocket-sized device (PSD) by ultrasound-trained residents during a night hospitalist rotation. Methods : Consecutive internal medicine residents ( n= 24), trained in a cardiac limited ultrasound examination (CLUE) as a mandatory part of their curriculum, were sampled on their PSD use after their admitting nights, regarding perceived necessity, deterring factors, detected abnormalities, and imaging difficulties. A detailed analysis was performed with one resident who used a PSD on every admission to compare the proportion of abnormal CLUEs and utility in patients with and without a perceived need. Results : Residents admitted 542 patients (mean age: 55±17 years, range: 17–95 years) during 101 shifts and performed CLUE on 230 patients (42%, range: 17–85%). Residents elected not to scan 312 (58%) patients due to 1) lack of perceived necessity (231, 74%), 2) time constraints (44, 14%), and 3) patient barriers (37, 12%). In the detailed analysis ( n= 71), the resident felt CLUE was necessary in 32 (45%) patients versus unnecessary in 39 (55%) patients, with abnormality rates of 50% versus 20.5% ( p= 0.01) and utility rates of 28.1% versus 15.4% ( p= 0.25), respectively. Conclusion : When unbiased residents acting as hospitalists are provided with a PSD to augment initial cardiac examination, usage is frequent and suggests clinical value in hospital medicine. Keywords: echocardiography; point-of-care ultrasound; hand-carried ultrasound; pocket-sized; hospitalist; hospital medicine (Published: 15 December 2016) Citation: Journal of Community Hospital Internal Medicine Perspectives 2016, 6 : 33358 - http://dx.doi.org/10.3402/jchimp.v6.3335
The adhesion of copper films deposited onto aluminum nitride

Good adhesion between copper film and AlN substrate is obtained when the surface of AlN is laser-irradiated prior to copper film deposition and post deposition annealing is conducted. Surface chemistry of AlN substrates before and after laser irradiation and the interfacial reactions of copper film/AlN couples were studied with Auger Electron Spectroscopy (AES) to understand the adhesion mechanisms. The surface of as-received AlN substrates was covered with a thin sheath of Al2O3. Laser irradiation removed the surface Al2O3 layers, smoothened the surface, and decomposed AlN leaving metallic aluminum on the surface. The interfacial reactions in the copper film/AlN couple are affected by the amounts of oxygen and metallic aluminum available at the interface. The adhesion mechanism is the formation of a Cu-O-Al compound at the interface of copper film/AlN couple. Since copper does not react with AlN, laser induced decomposition of AlN seems to be the driving force for the formation of the compound.
Hole polarons and p -type doping in boron nitride polymorphs

Boron nitride polymorphs hold great promise for integration into electronic and optoelectronic devices requiring ultrawide band gaps. We use first-principles calculations to examine the prospects for $p$-type doping of hexagonal ($h\ensuremath{-}\mathrm{BN}$), wurtzite ($wz\ensuremath{-}\mathrm{BN}$), and cubic ($c\ensuremath{-}\mathrm{BN}$) boron nitride. Group-IV elements (C, Si) substituting on the N site result in a deep acceptor, as the atomic levels of the impurity species lie above the BN valence-band maximum. On the other hand, group-II elements (Be, Mg) substituting on the B site do not give impurity states in the band gap; however, these dopants lead to the formation of small hole polarons. The tendency for polaron formation is far more pronounced in $h\ensuremath{-}\mathrm{BN}$ compared to $wz\ensuremath{-}\mathrm{BN}$ or $c\ensuremath{-}\mathrm{BN}$. Despite forming small hole polarons, Be acceptors enable $p$-type doping, with ionization energies of 0.31 eV for $wz\ensuremath{-}\mathrm{BN}$ and 0.24 eV for $c\ensuremath{-}\mathrm{BN}$; these values are comparable to the Mg ionization energy in GaN.