cssi/SciSciGPT-SciSciNet huggingface dataset:
The Sociotechnical Factors Associated With Burnout in Residents in Surgical Specialties: A Qualitative Systematic Review.

OBJECTIVE The consequences of burnout remain prevalent within general surgery training programs, yet there is no comprehensive description of the factors associated with burnout. Using sociotechnical systems theory, this review aims to qualitatively evaluate the factors associated with burnout in surgical residents. DESIGN A systematic review of the literature was performed according to The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The review was conducted using PubMed, Web of Science, Scopus, and Embase. Two reviewers independently selected studies, extracted data, and assessed quality, with a third reviewer acting as a moderator to resolve conflicts. The Systems Engineering Initiative for Patient Safety framework was utilized to categorize factors as either contributing to or mitigating burnout. The study was registered with PROSPERO (CRD42021237448). SETTING Included studies were conducted within the United States and published prior to November 11, 2020. PARTICIPANTS Included studies were peer-reviewed primary data, that were written in English and evaluated the sociotechnical factors associated with burnout in surgical residents. RESULTS A total of 4387 articles were identified and after review, 15 studies were included for analysis. Reported burnout rates ranged from 17 to 94%, with a total mean rate of 57%. Factors found to contribute to burnout include financial stress, work-life imbalance, excessive charting, insufficient job resources, poor social support, and mistreatment. Mitigating factors include having time away from work, increased didactics, supportive faculty, attending social events, and the presence of program-based wellness initiatives. Consequences of burnout include depression, substance abuse, and decreased job satisfaction. CONCLUSIONS Reported burnout rates among surgical residents are high. A complex number of sociotechnical factors were found to contribute to burnout, yet many factors are also shown to mitigate burnout. Surgical residencies may address burnout by making changes based on the presence or absence of these factors within their program.
Descartes Embodied: Descartes on Knowledge and Certainty: From the Discours to the Principia

Descartes is usually classed among the rationalists, those philosophers who privilege reason over experience. And indeed he belongs there. On the other hand, though, Descartes was also very interested in experiment. The Dioptrique and Meteores make a number of references to Descartes' experiments; the Discours discusses the importance of experiments at some length. In the Principia , written starting in early 1641 and published in 1644, Descartes refers to a number of experimental results to support his views, most visibly in the discussion of the magnet. And at the end of that book, he goes so far as to suggest that his vision of the world is ultimately supported by the fact that it is capable of explaining observed phenomena, and nothing more. Where is the real Descartes? Is he mathematician or experimenter? rationalist or empiricist? This is the larger question that I would like to explore in this essay. But I would like to address it in a rather particular and somewhat special way. Generally, discussions of Descartes' views about knowledge and experience concentrate on texts like the Meditations , and on issues concerned with knowledge of the kinds of grand questions that he takes up there, the knowledge of self, body, the distinction between mind and body, God, and so on. What I want to focus on is something much more mundane. The water we drink every day has a nature, from which follow certain well-known properties; water is wet and liquid at room temperature, solid when very cold, quenches thirst, admits light, but causes certain illusions, like the famous bent-stick illusion. All of this is somehow connected with its structure.
Robust Inferential Control for a Packed-Bed Reactor

An inferential robust control technique is applied to an experimental fixed bed reactor. The controlled variables are the exit concentration and the maximum bed temperature. Both controlled variables are inferred from one single temperature measurement. The location of this measurement is selected to optimize the performance of the closed-loop system when model uncertainty is allowed. Closed-loop experiments are conducted to test the robustness characteristics of the controller. From these experiments, the operating regions most sensitive to modelling uncertainty are determined. The nonlinear system characteristics can cause significant offset in the inferred controlled variables.
An algorithm for rendering generalized depth of field effects based on simulated heat diffusion

Depth of field refers to the swath through a 3D scene that is imaged in acceptable focus through an optics system, such as a camera lens. Control over depth of field is an important artistic tool that can be used to emphasize the subject of a photograph. In a real camera, the control over depth of field is limited by the nature of the image formation process and by physical constraints. The depth of field effect has been simulated in computer graphics, but with the same limited control as found in real camera lenses. In this paper, we use diffusion in a non-homogeneous medium to generalize depth of field in computer graphics by enabling the user to independently specify the degree of blur at each point in three-dimensional space. Generalized depth of field provides a novel tool to emphasize an area of interest within a 3D scene, to pick objects out of a crowd, and to render a busy, complex picture more understandable by focusing only on relevant details that may be scattered throughout the scene. Our algorithm operates by blurring a sequence of nonplanar layers that form the scene. Choosing a suitable blur algorithm for the layers is critical; thus, we develop appropriate blur semantics such that the blur algorithm will properly generalize depth of field. We found that diffusion in a non-homogeneous medium is the process that best suits these semantics.
Identification of integrin collagen receptors on human melanoma cells.

Abstract Integrin receptors may mediate the adhesion of cells to a number of extracellular matrix components. We found that the attachment of human melanoma cells to collagen types I and IV was blocked by antibodies to the integrin beta 1 subunit but not by peptides containing the Arg-Gly-Asp sequence. Ligand affinity chromatography was used to search for integrin-related receptors which mediate adhesion to native collagens. Detergent extracts of surface 125I-iodinated melanoma cells were chromatographed on type I or IV collagen-Sepharose columns. Bound material was eluted and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. EDTA, but not Arg-Gly-Asp peptides, eluted a mixture of two integrin-related heterodimeric complexes. Each complex contained the integrin beta 1 chain with Mr of 110,000 and a distinct alpha chain with Mr of either 200,000 or 150,000. Immunoprecipitation with specific monoclonal antibodies identified the complexes as very late activation antigen (VLA)-1 (alpha 1 beta 1) and VLA-2 (alpha 2 beta 1), respectively. The binding of these receptors to collagen appeared to be specific because they failed to be retained on fibronectin- or laminin-Sepharose columns. Immunofluorescent staining of cells on collagen substrates with antibodies to VLA-1 and VLA-2 localized these complexes in vinculin-positive adhesion plaques. In contrast, the receptor complexes were not detected in adhesion plaques of cells attached to fibronectin- or laminin-coated substrates. These results indicate that melanoma cells express at least two different integrin-related collagen-binding receptor complexes that appear to mediate cell adhesion to collagen.
Coordination among Rate-limiting Steps of Glycolysis and Respiration in Intact Ascites Tumor Cells

Abstract The accumulation of lactate and phosphorylated glycolytic intermediates, as well as the variation in adenosine triphosphate, diphosphate, and 5'-monophosphate, were measured over the first 4 min after addition of 0.77 mm glucose to Ehrlich ascites carcinoma cells in 54 mm phosphate buffer (pH 7.4) at 370 and 300. The rates of glucose flux through the phosphofructokinase step (Vpfk) and the lactate dehydrogenase step (Vldh) were calculated and compared with each other and the rate of oxygen consumption (Vr), measured by means of a bare, vibrating reed platinum electrode. During the period from 10 to 90 set or more after glucose addition, both Vr and Vpfk are linearly related to Vldh; at 370, Vpfk = 2.5 (Vldh - 1.1) and Vr = 0.38 (Vldh), where velocities are measured in micromoles per ml of cells per min; at 300, Vpfk = 4.1 (Vldh - 1.3) and Vr = 0.32 (Vldh). These results suggest a common controlling mechanism for all three rates. During the period from 10 to 60 sec approximately linear relationships between Vpfk, Vldh, and Vr and the ADP concentration are observed, but the slopes and intercepts of the lines vary considerably from one experiment to another unlike the relationships among the velocities themselves, which are almost identical in all experiments at the same temperature. In a given experiment, both Vldh and Vr extrapolate to the same ADP concentration (0 to 1.0 µmole per ml of cells) at zero velocity, which implies that if ADP is governing these rates only a fraction of the ADP may be involved in the control, but the same fraction or pool controls both respiration and glycolysis. The velocities are also approximately linear functions of esterified phosphate concentration. Since the increase in esters such as fructose diphosphate probably occurs at the expense of intracellular inorganic phosphate, this observation could be consistent with control of the rates by inorganic phosphate. The kinetic data do not identify either ADP or inorganic phosphate as the major controlling agent, but they do indicate a close coordination among the initial segment of glycolysis, the terminal segment of glycolysis, and respiration which is not fully explainable in terms of variations in either the ADP or phosphate levels in the whole cell.
H-alpha emission in hot degenerates and OB subdwarfs

Based on observations obtained using the 60-inch telescope at Palomar Observatory which is jointly owned by the California Institute of Technology and the Carnegie Institution of Washington and on observations obtained with the 200-inch Hale telescope which is owned by the California Institute of Technology.
Glutathione-coated cadmium-sulfide crystallites in Candida glabrata

Cadmium-sulfide crystallites form in the yeast Candida glabrata cultured in the presence of cadmium salts. The particles function to sequester and detoxify intracellular cadmium ions. The crystallites are peptide-coated, but the coating peptide varies with the nutrient conditions of the growth medium. When cultured in rich nutrient broth the yeast forms intracellular CdS particles coated with a mixture of glutathione and the γ-glutamylcysteine dipeptide. In contrast, cultures in synthetic minimal medium yield particles coated with polymerized γEC peptides of general structure (γ-Glu-Cys)n-Gly. Glutathione/γ-glutamylcysteine particles exhibit properties analogous to quantum, semiconductor-type crystallites. The optical properties are dependent on particle size, and irradiation results in photoluminescence and photoreduction not observed in bulk CdS mineral. Aerobic irradiation leads to particle decomposition presumably via oxidation of the sulfide ions within the crystallite.
Chapter 16 Phytoremediation of hydrocarbon-contaminated soils: principles and applications

Publisher Summary This chapter provides a strong foundation for understanding phytoremediation of petroleum hydrocarbon contaminated sites from principles to practice. Phytoremediation has developed into a more acceptable technology for the remediation of soils and groundwater polluted with residual concentrations of petroleum hydrocarbons. Phytoremediation is an emerging technology that is based on sound ecological engineering principles. Phytoremediation is a practical and cost-effective approach with aesthetical and atmospheric-carbon-sequestration ancillary benefits and is particularly attractive for rural areas with residual and shallow contamination. Phytoremediation holds great potential to manage a wide variety of environmental pollution problems, including the cleanup of soils and groundwater contaminated with hydrocarbons and other hazardous substances; the attenuation of pollutants dispersing through the environment in agricultural drainage, landfill leachates, and other forms of surface runoff or sub-surface migration; and the assimilation of industrial wastewater effluents to support efforts to move toward a zero-discharge policy from industrial facilities.
Growth of the human fetus: II. Abnormal growth in twins and infants of mothers with diabetes, hypertension, or isoimmunization

Abstract As would be expected, the chronic conditions under study have both nonspecific (chronic fetal distress) and specific effects on the fetus. Some quantitative changes amenable to statistical investigation have been studied, relating particularly to the pattern of fetal growth. In addition, information on mortality in relation to fetal growth has been obtained from the deaths within the series of births unselected except for the condition under study, and an additional autopsy series. According to these parameters some characteristics of chronic fetal distress are present in all abnormal groups studied. Growth retardation is most frequent and severe in twins, and considerably less so in fetuses from pregnancies associated with hypertension; however, mortality of growth retarded infants is considerably lower in the former than in the latter. Growth of the brain shows in both groups a pattern of incidence of abnormal weight scores consistent with growth retardation. Weight of the thymus has been studied only in perinatal deaths with normal birth weight, and these were insufficient in number in the two abovementioned groups. While in infants of diabetic mothers overgrowth is common, the brain and thymus are smaller than usual as would be expected in chronic fetal distress with growth retardation. Another puzzling feature is the time of appearance of the abnormalities studied, early in the third trimesten. It is concluded that these infants do not simply show the effects of nonspecific chronic fetal distress and overfeeding although both appear to be involved, but in addition have a specific disturbance, probably endocrine, which modifies their response to both. In isoimmunization the growth pattern of the body is not detectably abnormal but the brain tends to be small (less so than in infants of diabetics) and the thymus also (more so than in infants of diabetics). This suggests, as do other pathologic features, that there is a slight degree of the specific disturbance characterizing infants of diabetics, but greater severity of chronic fetal distress. However, these trends are not strong and cannot be interpreted with assurance.
Scaling Properties of Aerosol Optical Thickness Retrieved from Ground-Based Measurements

Statistical scale-by-scale analysis, for the first time, has been applied to the aerosol optical thickness (AOT) retrieved from the Multi-Filter Rotating Shadowband Radiometer (MFRSR) network. The MFRSR data were collected in September 2000 from the dense local network operated by the U.S. Department of Energy Atmospheric Radiation Measurement program, located in Oklahoma and Kansas. These data have 20-s temporal resolution. The instrument sites form an irregular grid with the mean distance between neighboring sites about 80 km. It is found that temporal variability of AOT can be separated into two well-established scale-invariant regimes: 1) microscale (0.5‐15 km), where fluctuations are governed by 3D turbulence, and 2) intermediate scale (15‐100 km), characterized by a transition toward large-scale 2D turbulence. The spatial scaling of AOT was determined by the comparison of retrievals between different instrument sites (distance range 30‐400 km). The authors investigate how simultaneous determination of AOT scaling in space and time can provide means to examine the validity of Taylor’s frozen turbulence hypothesis. The temporal evolution of AOT scaling exponents during the month appeared to be well correlated with changes in aerosol vertical distribution, while their spatial variability reflects the concavity/convexity of the site topography. Explanations based on dynamical processes in atmospheric convective boundary layer are suggested.
Selenium in forage crops and cancer mortality in U.S. counties.

The potential protective effect of selenium status on the risk of developing cancer has been examined in animal and epidemiologic studies. This ecological study investigated the association between U.S. county forage selenium status and site- and sex-specific county cancer mortality rates (1950-1969) using weighted least squares regression. Consistent, significant (p less than .01) inverse associations were observed for cancers of the lung, rectum, bladder, esophagus, and cervix in a model limited to rural counties and for cancers of the lung, breast, rectum, bladder, esophagus, and corpus uteri in a model of all counties. No consistent significant positive associations were observed in the rural county models. This remarkable degree of consistency for the inverse associations strengthens the likelihood of a causal relationship between low selenium status and an increased risk of cancer mortality.
Dissolution of a Multiphase Waste Form

The dissolution behavior of the ceramic waste form (CWF) is being investigated to support its qualification for disposal in the proposed repository at Yucca Mountain. The CWF consists of sodalite and glass phases and has been consolidated either by hot isostatic pressuring (HIP) or by pressureless consolidation (PC). In this paper we compare the dissolution behavior of the two materials using in MCC-1 type tests at 90°C in a simulated silicate groundwater. The test solutions were periodically exchanged limit feedback effects. The solid surface area to volume ratio was 10 m-1. Five types of samples were tested: (1) HIP CWF, (2) binder glass vitrified by HIP, (3) PC CWF, (4) binder glass vitrified by PC, and HIP sodalite. Boron releases were used to monitor glass dissolution; these were similar in tests with HIP CWF, HIP glass, and PC CWF, but about 3X higher in tests with PC glass. At the end of the tests, the surfaces of the reacted materials were examined with scanning electron microscopy for signs of preferential dissolution. Differences in the dissolution behaviors of the materials are described and the implications of the test results regarding the performance of the CWF in the disposal system are discussed.
On Use of Multiple Tests of Significance in Psychological Research

The evaluation of a series of statistical tests in psychological research is a common problem faced by many investigators. As the number of statistical tests increases, the probability of making a ...
Propagating waves in human motor cortex.

Previous studies in non-human primates have shown that beta oscillations (15-30Hz) of local field potentials (LFPs) in the arm/hand areas of primary motor cortex (MI) propagate as traveling waves across the cortex. These waves exhibited two stereotypical features across animals and tasks: 1) The waves propagated in two dominant modal directions roughly 180 degrees apart, and 2) their propagation speed ranged from 10 ~ 35 cm/s. It is, however, unknown if such cortical waves occur in the human motor cortex. This study shows that the two properties of propagating beta waves are present in MI of a tetraplegic human patient while he was instructed to perform an instruction delay center out task using a cursor controlled by the chin. Moreover, we show that beta waves are sustained and have similar properties whether the subject was engaged in the task or at rest. The directions of the successive sustained waves both in the human subject and a nonhuman primate (NHP) subject tended to switch from one dominant mode to the other, and at least in the NHP subject the estimated distance travelled between successive waves traveling into and out of the central sulcus is consistent with the hypothesis of wave reflection between the border of motor and somatosensory cortices. Further, we show that the occurrence of the beta waves is not uniquely tied to periods of increased power in the beta frequency band. These results demonstrate that traveling beta waves in MI are a general phenomenon occurring in human as well as non-human primates. Consistent with the non-human primate data, the dominant directions of the beta LFP waves in human aligned to the proximal to distal gradient of joint representations in MI somatotopy. This consistent finding of wave propagation may imply the existence of a hardwired organization of motor cortex that mediates this spatio-temporal pattern.
Generation of intramolecular and intermolecular sulfenamides, sulfinamides, and sulfonamides by hypochlorous acid: a potential pathway for oxidative cross-linking of low-density lipoprotein by myeloperoxidase.

Oxidized low-density lipoprotein (LDL) is implicated in atherogenesis, and human atherosclerotic lesions contain LDL oxidized by myeloperoxidase, a heme protein secreted by activated phagocytes. Using hydrogen peroxide (H2O2), myeloperoxidase generates hypochlorous acid (HOCl), a powerful oxidant. We now demonstrate that HOCl produces sulfenamides, sulfinamides, and sulfonamides in model peptides, which suggests a potential mechanism for LDL oxidation and cross-linking. When we exposed the synthetic peptide PFKCG to HOCl, the peptide's thiol residue reacted rapidly, generating a near-quantitative yield of products. Tandem mass spectrometric analysis identified the products as the sulfenamide, sulfinamide, and sulfonamide, all formed by intramolecular cross-linking of the peptide's thiol and lysine residues. An intramolecular sulfinamide was also observed after the peptide PFRCG was exposed to HOCl, indicating that the guanidine group of arginine can also form a sulfur−nitrogen cross-link. The synthetic pe...
Talar Neck Fractures: A Systematic Review of the Literature

Considerable controversy surrounds the management of talar neck fractures regarding the rate of post-traumatic arthrosis, secondary procedures, avascular necrosis, and the effect of the interval to surgery on these variables. A data search using PubMed was performed with the keywords "talus" and "fracture." The search found 1280 studies. Ultimately, 21 reports involving 943 talar neck fractures were analyzed. Data concerning open fractures, the interval to surgery and its relationship to the incidence of avascular necrosis, and the rates of malunion and nonunion, post-traumatic arthrosis, secondary salvage procedures, and functional outcomes were collected and analyzed. The variables examined were not uniformly reported in all studies. The overall rate of avascular necrosis was 33%, with no demonstrated relationship between the interval to surgery and the rate of avascular necrosis. Malunion occurred approximately 17% of the time, with nonunion occurring approximately 5% of the time. Post-traumatic arthrosis occurred in 68% of patients, although secondary salvage procedures were only performed in 19% of patients. Functional outcomes were difficult to assess, given the variability of reported outcomes and unvalidated measures. The optimal management of talar neck fractures has yet to be determined. Although the present review has improved understanding of these difficult fractures, additional studies that use validated outcomes measures are warranted to determine the effect of delayed surgery on final outcomes and optimal treatment methods.
“Need to Know” in engineering programs; STEMing the uncertainty around graduate education

A country's leadership in global technological and scientific development depends on its ability to recruit and retain students into engineering master's and doctoral programs. This qualitative study aims to develop a fuller understanding of the factors driving U.S. students' decision-making processes with respect to pursuing a graduate degree in engineering. During the fall of 2010, more than 1400 undergraduate engineering students and 800 graduate students at four universities across the United States completed surveys containing open-ended questions that allowed students to express their thoughts about and experiences in engineering graduate education. Thematic analysis of 256 undergraduate student responses focused on the barriers and supports underlying their decisions to pursue graduate education (including uncertainty in the application process, availability of funding, and concern about the grade point average requirement). The responses of 220 graduate students focused on the steps important for successful preparation for and navigation of graduate school (including strong theoretical and research preparation, clear goals for pursuing the degree, choice of advisor/research group, and selection of an engaging research topic). These results clarify the factors influencing undergraduate students' decision-making regarding graduate engineering education, and the qualitative training experiences of students in graduate school. These findings provide undergraduate students a starting point on questions to ask when considering graduate school while alleviating their potential misconceptions. The results also help engineering faculty and administrators improve recruitment of potential graduate students and improve their training experiences.
A new method of determining the total flux of environmental gamma radiation by a 2″Ø×2″ NaI(Tl) scintillation counter

Abstract A convenient and easy method for estimating the flux of environmental gamma radiation by measuring counting rate and electric current from a photomultiplier tube coupled to a 2″O×2″ NaI(Tl) scintillator has been developed.
Giant Resonances as Oscillations of Two Elastically Coupled Fluids

The classical equations of motion for elastically coupled, elastic proton and neutron fluids allow two $T=0$ and two $T=1$ propagating modes. The Lam\'e coefficients evaluated empirically are seen to be very different from each other, yielding the large Poisson ratio of 0.485 for nuclear matter and the $T=0$ and $T=1$ giant-resonance energies, many of which have been seen experimentally.
Quantifying Thermally Driven Fracture Geometry During CO2 Storage

Abstract The desired lifetime for CO 2 injection for sequestration is several decades at a high injection rate (up to 10 bbl/min or 2,400 tons/day per injector). Government regulations and geomechanical design constraints may impose a limit on the injection rate such that, for example, the bottomhole pressure remains less than 90% of the hydraulic fracture pressure. Despite injecting below the critical fracture pressure, fractures can nevertheless initiate and propagate due to a thermoelastic stress reduction caused by cool CO 2 encountering hot reservoir rock. Here we develop a numerical model to calculate whether mechanical and thermal equilibrium between the injected CO 2 and the reservoir evolves, such that fracture growth ceases. When such a condition exists, the model predicts the corresponding fracture geometry and time to reach that state. The critical pressure for fracture propagation depends on the thermoelastic stress, a function of rock properties and the temperature difference between the injected fluid and the reservoir ( ΔT ). Fractures will propagate as long as the thermoelastic stress and the fluid pressure at the fracture tip exceed a threshold; we calculate the extent of a fracture such that the tip pressure falls below the thermoelastically modified fracture propagation pressure. Fracture growth is strongly dependent upon the formation permeability, the level of injection pressure above fracture propagation pressure, and ΔT .
Strong CH...halide hydrogen bonds from 1,2,3-triazoles quantified using pre-organized and shape-persistent triazolophanes.

The structures associated with halide (F - , Cl - , Br - ) complexation inside CH hydrogen-bonding macrocyclic receptors, called triazolophanes, are characterized using density functional theory (DFT). The associated binding energies in the gas and solution phases are evaluated. The ruffles in the empty triazolophane become smoothed-out upon Cl - - and Br - -ion binding directly into the middle of the cavity. The largely pre-organized cavity morphs into an elliptical shape to facilitate shorter hydrogen bonds in the north and south regions and longer ones west and east. The smaller F- ion sits in, and flattens-out, only the north (or south) region. The 1,2,3-triazoles show shorter CH ... Cl - contacts than for the phenylenes. Both Cl - and Br - show the same binding geometries but Cl - has a larger binding energy consistent with its stronger Lewis basicity. Model triads were used to decompose the overall binding energy into those of its components. In the course of this triad analysis, anion polarization was identified and its contribution to the triad...Cl - binding energy estimated. Consequently, the binding energies for the individual aryl units within the comparatively non-polarized triazolophanes were estimated. The 1,2,3-triazoles are twice as strong as the phenylenes thus contributing most of the interaction energy to Cl - -ion binding. Therefore, the 1,2,3-triazoles appear to approach the hydrogen bond strengths of the NH donors of pyrrole units.
Photo-excitation of single crystals of La2CuO4+δ near the metal-insulator transition

Abstract Transient photoconductivity (σ ph ) experiments have been carried out in single crystals of insulating La 2 CuO 4+δ near the metal-insulator transition ( δ ≈ 1–2%). The time evolution of the σ ph changes dramatically with light intensity ( I L ). At low I L , σ ph is characterized by power law time decay, t − α , in the nanosecond time regime, and the exponent, α, decreases significantly with increasing I L . As I L increases to 5 × 10 15 photons/cm 2 , σ ph reaches ∼ 15 S/cm, and the lifetime of the conducting state is enhanced by more than two orders of magnitude: σ ph exhibits a delayed peak centered at approximately 30 ns. followed by exponential decay with time constant of ∼ 360 ns. The data reveal a continuous distribution of localized electronic states above the (hole) mobility edge; the M-I transition is achieved when the Fermi level is shifted away from the localized states and across the mobility edge either by chemical dopiing or by photo-excitation. The time of σ ph at high I L implies the formation of metastable metallic droplets after photo-excitation.
On the Sumrate of Amplify-and-Forward Relay Networks with Multiple Source-Destination Pairs

The paper considers a network scenario in which multiple source-destination node pairs need to communicate simultaneously. Each source and destination is equipped with one antenna and the communication is assisted by a multi-antenna relay operating in Amplify-and-Forward fashion. The communication occurs in two slots; in the first slot, the sources transmit simultaneously, and in the second slot, the relay retransmits the signals which were received by its antennas during the first slot, after linearly processing them via a Zeroforcing Beamforming (ZFBF) matrix. Two different designs for the ZFBF matrix are proposed. The first design allocates the relay power so that all data streams have the same useful power. The second design adjusts the relay weights for all S-D pairs in a way that maximizes the sumrate. It is shown analytically that, when the source or relay power is high, the proposed sumrate maximization method has the same ergodic sumrate as the cut-set bound with two identical slots and a ZF precoder in the broadcast hop or a ZF equalizer in the multiple access hop, or maintains a constant gap from the cut-set bound with a ZF precoder in the broadcast hop. Although initially perfect channel state information (CSI) is assumed available at the relay, an upper bound of the ergodic sumrate loss caused by relay CSI errors is also derived.
Do Materialism, Intrinsic Aspirations, and Meaning in Life Predict Students' Meanings of Education?.

Though there is a deep literature on factors that predict college attendance and on the effects of college attendance on students’ development, there has been little research on what education actually means to students themselves. This study was conducted to examine whether materialism, intrinsic aspirations, and the search for meaning in life predicted a set of ten meanings that students are known to associate with their education. Multiple regression analyses indicated that students who were high on materialism viewed their education as an opportunity to gain independence, a chance to establish relationships, and a source of stress. Individuals high on intrinsic aspirations were more likely to see education as a time for career preparation, gaining independence, exploring future life directions, learning, engaging in personal growth, establishing social relationships, and learning skills to make a difference in the world, but they were less likely to view education as an escape from future responsibilities. As expected, the findings also revealed that individuals who sought meaning in life viewed education as a way to gain independence, explore life directions, engage in personal growth, establish relationships, learn skills that will help change the world, and escape future responsibilities.
Thermal behavior of ZrCu metallic glasses

Abstract ZrCu metallic glasses containing between 50 and 66.5% copper were prepared in an arc furnace quenching unit. Scanning calorimetry was used to characterize the glass transition temperature T g , the crystallization temperature T c and the heat of crystallization ΔH c . T g and T c were found to increase monotonically with increasing copper content over the composition range studied while Δ c decreased linearly with increasing copper content; T c − T g remained approximately constant. An exothermic relaxation effect, qualitatively similar to that previously reported for metal-metalloid glasses, was observed over a temperature range of about 100 K immediately preceding T g .
An analysis of masticatory form and function in three mustelids (Martes Americana, Lutra canadensis, Enhydra lutris)

An analysis of the masticatory apparatus of three mustelids ( Martes, Lutra, Enhydra ) is presented. Descriptions are provided for dentition, cranial morphology, primary jaw musculature, and jaw mechanics. The most striking differences noted among the three genera are in the dentition, with the cheek teeth showing extreme modification toward grinding in the species examined. The cranium, jaw muscles, and jaw mechanics are more conservative. These results lend support to the hypothesis that the greatest variation in the components of the mammalian jaw apparatus is contributed by the shape of the teeth (Hiiemae, 1978).
Charge-Transfer Excitation of Impurity Ions in Tokamaks

Detailed studies of spectra from the ISX-$A$ (Impurity Study Experiment) tokamak at the Oak Ridge National Laboratory have shown that certain oxygen-ion lines appear too anomalously intense to have been excited solely by electron collisions. These results are interpreted as being due to charge transfer and suggest the necessity of incorporating this mechanism into analyses of tokamak plasmas.
Apical ballooning syndrome or aborted acute myocardial infarction? Insights from cardiovascular magnetic resonance imaging.

Introduction Apical Ballooning Syndrome (ABS) is a novel acute cardiac syndrome that mimics acute myocardial infarction (AMI). This study evaluates the diagnostic utility of cardiac magnetic resonance imaging (CMR) in patients with suspected ABS. Methods and Materials Contrast-enhanced CMR was performed in 13 consecutive patients with suspected ABS on the basis of their initial clinical presentation and cardiac catheterization results. Results Ten patients (all female, mean age 71 ± 8 years) had an eventual diagnosis of ABS. CMR demonstrated left ventricle regional wall motion abnormalities (RWMA) involving the apex and mid-ventricle. Six also had right ventricular apical akinesis. There was no myocardial delayed enhancement (MDE) in these patients. The remaining three patients had initial features suggestive of ABS but were eventually determined to have AMI. Left ventriculography showed typical apical ballooning that was not explained by coronary angiography results. Two had MDE and persistent RWMA consistent with anterior AMI. One had RWMA on CMR consistent with a single vascular territory, and subsequent intravascular ultrasound showed obstructive plaque in the left anterior descending (LAD) artery. The final diagnosis in these patients was AMI with clot lysis prior to coronary angiography. Conclusion While ABS mimics AMI, AMI with spontaneous clot lysis may also mimic ABS, and at least in some patients, be mistaken for ABS. ABS is characterized by the absence of MDE and complete myocardial viability on CMR. The diagnosis of ABS can be excluded if CMR demonstrates MDE consistent with myocardial necrosis in a pattern and distribution consistent with AMI.
Torsion, Parity-odd Response and Anomalies in Topological States

We study the response of a class of topological systems to electromagnetic and gravitational sources, including torsion and curvature. By using the technology of anomaly polynomials, we derive the parity-odd response of a massive Dirac fermion in $d=2+1$ and $d=4+1$, which provides a simple model for a topological insulator. We discuss the covariant anomalies of the corresponding edge states, from a Callan-Harvey anomaly inflow, as well as a Hamiltonian spectral flow point of view. We also discuss the applicability of our results to other systems such as Weyl semimetals. Finally, using dimensional reduction from $d=4+1$, we derive the effective action for a $d=3+1$ time-reversal invariant topological insulator in the presence of torsion and curvature, and discuss its various physical consequences.
Potent effects of low levels of MHC class II-associated invariant chain on CD4+ T cell development.

Abstract Invariant chain (li)-negative mice exhibit defects in MHC class II assembly and transport that results in reduced levels of surface class II, altered antigen presentation, and inefficient positive selection of CD4 + T cells. Many CD4 + T cells that do mature in li-negative mice express a cell surface phenotype consistent with aberrant positive selection or peripheral activation. Reconstitution of these mice with low levels of either the p31 or p41 form of Ii does not restore transport of the bulk of class II or class II surface expression, but surprisingly does restore positive selection as measured by numbers and surface phenotype of CD4 + T cells. Thus, an li-dependent process, independent of effects on class II surface density, appears to be required for normal positive selection of CD4 + T cells.
Membrane formation during sclerotization of Physarum polycephalum plasmodia

Abstract In the plasmodial slime molds, during the transition from the vegetative or plasmodial stage to the dormant sclerotial stage, a large increase in protoplast surface membrane occurs. Electron micrographic evidence is presented to suggest that this new surface arises from the fusion of already existing vesicles. Evidence for a similar process is available in many other organisms. All of these data seem to support the general concept of interconvertibility of biological membranes.
Radiologic features of well-differentiated osteosarcoma.

Eight cases of well-differentiated, intramedullary osteosarcoma were studied. In three cases, the lesions previously had been diagnosed, pathologically and radiologically, as benign. The distal femur was the most frequent site. Radiographically, the tumor margins were poorly defined in five cases and were well defined in three. In seven cases, the bone response pattern was both lytic and blastic; in one case, it was purely lytic. Tumor matrix patterns were mostly homogeneous and cloudlike. Four of the lesions were expansile. All cases had cortical thinning and discontinuity. Extraosseous involvement of the soft tissues was present in six cases, and active periosteal response was present in two. High-grade malignancies subsequently developed in two patients--one was a local recurrence and the other was a distant metastasis. A broad spectrum of radiologic features was observed in well-differentiated intramedullary osteosarcomas, but all cases had at least two of three radiographic findings (cortical discont...
Preparation of the anhydrous rare earth trichlorides, tribromides, and triiodides

Abstract A new method is presented for preparing an anhydrous rare earth trihalide using the reaction of excess mercuric halide with the rare earth metal. The trihalide products may be purified by vacuum distillation.
System Dynamics and the Electric Power Industry

System dynamics has been used extensively to aid in resource planning in the electric power industry. The many applications constitute a major body of work that has proven useful to large and small power companies as well as to government agencies at the local, state and federal level. The work has been performed by utility analysts, government planners, consultants and academics. One of my recent publications on electric power was honored with the 1996 Jay Wright Forrester Award. This article documents the major points in my award address to the 1996 International System Dynamics Conference. It summarizes the impressive body of work that system dynamics practitioners have accumulated over the past several decades. It gives my interpretation of the important and unique features of the system dynamics approach. I argue also that we have contributed to useful change in the electric power industry. © 1997 by John Wiley & Sons, Ltd.
The impact of technology on product design, productivity, and profits: a duopoly model of price-quality competition

This paper develops a two stage economic model of duopoly competition to examine the impact of technology investments in product design tools on product quality and price, firm productivity and profits, and consumer welfare. In the first stage the firms simultaneously choose product quality and in the second stage, after observing each other's quality choices, the firms simultaneously set prices. This model captures the firm's option to leverage technology tools to improve product quality and tracks the effect of such quality adjustments on measures of firm performance and consumer welfare. More specifically, the findings show that profit-maximizing firms leverage technology-based design tools to improve product quality, resulting in higher levels of firm profits and consumer welfare; however, these improvements come at the expense of productivity. Alternatively, the findings show that firms that fail to improve quality, and instead leverage the tools to reduce production costs, realize higher levels of productivity; however, this improvement in productivity comes at the expense of profits and consumer welfare. The results of the analytical model cast a new light on why it may be reasonable to empirically observe reductions in firm productivity following investments in IT tools that improve production capabilities.
Thin-layer mapping of peptides labeled with 3H or 14C via reductive methylation.

Abstract Two dimensional tryptic peptide maps have been obtained from 2 μg (40 pmol) of protein digest following labeling with 3H or 14C via reductive methylation. A simple labeling procedure is complete within 1 h; autoradiographs of 14C-labeled maps and fluorographs of 3H-labeled maps are obtained in 72 and 24 h, respectively. Tryptic peptide maps of 14 C 3 H methylated α- and β-tubulin, and rabbit muscle, chick muscle, and chick brain actins show approximately the expected number of peptides. Methylation does not appear to measurably alter the map positions of the peptides relative to unmethylated peptides in the solvent systems used for either electrophoresis or chromatography.
Developmental programming of hypothalamic feeding circuits

The hypothalamus plays a critical role in the regulation of food intake and body weight, and recent work has defined a core circuitry in the hypothalamus that appears to mediate many of the effects of the adipocyte-derived hormone leptin on feeding and glucose homeostasis. However, until recently, little was known about the development of these critical pathways. This review summarizes recent advances regarding the post-natal development of 'metabolic' projections from the arcuate nucleus of the hypothalamus. Evidence accumulated primarily in mice indicates that these circuits develop after birth and remain both structurally and functionally immature until the second week of life. Recent studies have begun to identify cues governing development of these pathways, and leptin appears to play a crucial neurotrophic role in the development of the hypothalamic circuits regulating food intake and adiposity. The neurodevelopmental actions of leptin appear specifically to be restricted to a neonatal critical period that coincides with the naturally occurring surge in leptin. In addition, the timing and amplitude of the post-natal leptin surge has important consequences for normal body weight regulation and glucose homeostasis later in life. Ultimately, these data promise to provide new insight into the mechanisms by which alteration of perinatal nutrition may have long-term consequences on body weight regulation and adiposity in the offspring.
Images don't forget: Online photogrammetry to find lost graves

The vast amount of public photographic data posted and shared on Facebook, Instragram and other forms of social media offers an unprecedented visual archive of the world. This archive captures events ranging from birthdays, trips, and graduations to lethal conflicts and human rights violations. Because this data is public, it has led to a new genre of journalism, one led by citizens finding, analyzing, and synthesizing data into stories that describe important events. To support this, we have built a set of browser-based tools for the calibration and validation of online images. This paper presents these tools in the context of their use in finding two separate lost burial locations. Often, these locations would have been marked with a headstone or tomb, but for the very poor, the forgotten, or the victims of extremist violence buried in unmarked graves, the geometric cues present in a photograph may contain the most reliable information about the burial location. The tools described in this paper allow individuals without any significant geometry background to utilize those cues to locate these lost graves, or any other outdoor image with sufficient correspondences to the physical world. We highlight the difficulties that arise due to geometric inconsistencies between corresponding points, especially when significant changes have occurred in the physical world since the photo was taken, and visualization features on our browser-based tools that help users address this.