cssi/SciSciGPT-SciSciNet huggingface dataset:
When Local Housing Becomes an Electronic Instrument: The Global Circulation of Mortgages — A Research Note

The securitizing of mortgages has brought with it a new channel for extracting household income, bundling it up with other types of debt and selling it off to financial investors. Extending this concept to modest-income households opens up a global potential market comprising billions of households. The first part of this article examines how mortgages for modest-income households could jump circuits and function as investment instruments in the secondary financial circuit, thereby making the creditworthiness of mortgage holders irrelevant as a source of profit, to the disadvantage of modest-income households. The second part examines the potential for this mechanism in major regions of the world. The critical indicator used is the low ratios of residential mortgage capital to GDP, a ratio far lower than in the US and other developed economies. The final section examines the costs of this innovation — for cities, for various countries and for banks. Resume Avec la titrisation des credits hypothecaires, est apparu un nouveau canal de prelevement des revenus des menages, amalgamea d’autres types de dettes et revendu a des investisseurs financiers. Etendre ce concept aux menages modestes ouvre sur un marche potentiel mondial de plusieurs milliards de foyers. Dans une premiere partie, ce travail etudie comment les prets hypothecaires destines aux menages a revenus modestes ont pu passer d’un circuit a un autre jusqu’a operer comme instruments de placement sur le circuit financier secondaire, rendant la solvabilite des creanciers hypothecaires insignifiante en tant que source de profit, au desavantage des menages modestes. Dans une deuxieme partie, est examine le potentiel de ce mecanisme dans les grandes regions du globe. Le principal indicateur utilise est la faiblesse des ratios ‘capitaux des credits hypothecaires au logement sur PIB’, un ratio tres inferieur au Etats-Unis et dans d’autres economies developpees. La derniere partie s’interesse aux couts de cette innovation, a la fois pour les villes, les differents pays et les banques.
Analysis of Superconducting Dipole Coil of 11 GeV Super High Momentum Spectrometer

Jefferson Lab is constructing five Super High Momentum Spectrometer (SHMS) superconducting magnets for the 12 GeV Upgrade. This paper reports measured coil material properties and the results of the extensive finite element analysis (FEA) for the dipole coil. To properly define the smeared orthotropic material of the coil, a detailed coil model is set up to compute material parameters because not all parameters were measured. Stress and strain acceptance criteria are discussed. Eight load steps are defined. The preheat temperature of the force collar is optimized under two loading scenarios so that the positive pressure between the inner coil and central spacer is maintained while there is not too much squeeze to the coil.
The experimental modification of teacher attending behavior

A method of observing and modifying teacher attention to appropriate child responses in preschool classrooms was developed. Two teachers with no formal training in reinforcement principles were observed for a baseline of eight days. Teacher A, who displayed a lower baseline rate of attending to appropriate child responses, was trained first. Teacher B was simply observed during the first part of the training condition for Teacher A. During training, A received feedback which included definitions of appropriate child responses, her frequency of attending to appropriate child responses, her total percentage of attending to appropriate child responses, and her frequency of failing to attend to appropriate child responses. Teacher B was then trained in a similar way. Both teachers showed an increase in attending to appropriate child responses subsequent to the onset of experimental feedback.
Reproduction of Human Ulcerative Pulmonary Tuberculosis in Rabbits by Quantitative Natural Airborne Contagion.

SummaryA modification of an apparatus for quantitative airborne infection as devised by Wells is described. Its use has indicated that, while the number of tubercles generated in the lung is to a certain degree proportional to the number of droplet nuclei of tubercle bacilli inhaled, there is no constant ratio between the number of tubercle bacilli arrested in the lung and the number of primary tubercles generated therein, even when the rabbits breathe the same infected air simultaneously.By exposing vaccinated highly inbred, genetically resistant rabbits to the inhalation of known small numbers of virulent bovine type tubercle bacilli it was possible to reproduce various types and phases of human localized ulcerative pulmonary tuberculosis of the adult or reinfection type. These phases ranged from complete resistance to the infection to varying degrees of bronchogenic dissemination from excavated foci to one or both lungs. There was little or no lymphogenous or hematogenous dissemination from the pulmona...
Force and conductance molecular break junctions with time series crosscorrelation

Force and conductance, measured across 4,4′-bipyridine simultaneously, are crosscorrelated using a two dimensional (2D) histogram method. The result is a 2D multivariate statistical analysis superior to current one dimensional histogram techniques for exploring significant conductance and force modulations within SMBJs. This method is sensitive enough to crosscorrelate signal modulations between force and conductance traces associated with contact geometry perturbations predicted in literature such as Au–molecule contact twisting and slipping during junction elongation.
Alligators in natural areas: Choosing conservation policies consistent with local objectives

Abstract In parks and reserves, the conservation and management of large animals, particularly dangerous ones, has always been of concern with respect to human safety. In some areas, protective management for crocodilians, some species of which are known to attack humans, is appropriate despite prevailing national or regional management trends emphasising commercial utilisation. Management of problem alligators in Everglades National Park provides an example of protection management. We found that incidents involving conflict between visitors and alligators were not frequent in the Park despite a large resident alligator population and the annual passage of 400 000 people through the area. Furthermore, responses to alligator incidents were not time-consuming, requiring an average of four personnel-days per year. Visitor management was an effective tool in this park, emphasising a balance between visitor safety and alligator protection by focusing on reducing the potential for conflict. Because objectives differ in various reserves, there is a need for locally sensitive planning for crocodilian management. Three criteria to be evaluated at a local level are potential threats to human safety, economic necessity, and the ecological values of the species. Although ethical and philosophical arguments can be raised, in the United States nonconsumptive management appears to be most effectively argued on the value of crocodilians to the ecosystems they inhabit.
Temperature dependence of allethrin-induced repetitive discharges in nerves

Abstract The action of allethrin in inducing repetitive discharges by a single stimulus has been studied with squid giant axons at various temperatures. Repetitive discharges are evoked in the allethrin-poisoned axon at optimal temperatures ranging from 20 to 28°C. A single action potential is produced below and above this temperature range. The negative (depolarizing) after-potential is increased markedly by allethrin, and it exceeds the threshold membrane potential for excitation only at the optimal temperatures, thereby accounting for the temperature dependence of repetitive responsiveness.
Modeling Approach and Predictions of Boron Mixing in Core Bypass of ESBWR

Computational fluid dynamics (CFD) is used to predict the mixing and transport of a Boric acid solution in the core bypass region of the General Electric (GEH) Economic Simplified Boiling Water Reactor (ESBWR) during an anticipated transient without scram (ATWS) scenario. Transient boundary conditions are synthesized from a set of system code predictions. Full-scale CFD predictions are completed using a representative geometry. Symmetry is used to reduce the domain to 1/8th of the core bypass. Forty-five million finite volume cells are used to define the computational domain inside the core barrel which is made up of the small passages between the fuel channels and an outer peripheral open space. The size of the model posed special challenges in the FLUENT CFD model development and execution. The solution required a large number of iterations with reduced solver under-relaxation factors to ensure stable convergence. Steady-state predictions were completed to quantify the sensitivity of the results to variations in selected boundary conditions. These results show good transport of the Boron into the inner regions of the core bypass with no significant sensitivity of the result to changes in the distribution of flow from the top surface. The results also showed no significant impact to changing the specific gravity of the incoming jets from 1.05 to 1.0. Only a significant change in the leakage rate from the bypass and/or a change in the mass flow rate of injected Boron solution were able to impact the distribution and quantity of the Boron in the core. These results are in line with expectations. The predictions indicate efficient penetration of the Boron into the interior regions of the core bypass during an ATWS.
Failure prediction of the total hip prosthesis system

Abstract The mechanical failure of the prosthesis-cement-femur system is analyzed by using a two-dimensional finite element model. The strain energy density (SED) criterion is applied to locate potential failure sites in the PMMA and prosthesis stem for five different prosthesis positions. Medial and lateral failure sites in the proximal regions of the cement are found to be the most sensitive to prosthesis position. According to the SED criterion, these are the weakest regions of the cement. Additional bilateral failure sites are also located at the distal end of the prosthesis, but are less likely to fail. The overall structural integrity of the total hip system is found to be adequate for the ideal case considered herein. In practice, the combination of energy concentration coupled with imperfections such as voids and cracks in the cement are potential sites of failure initiation. On the basis of clinical evidence on cement and prosthesis stem fracture, local reductions in the cement elastic modulus were introduced into the finite element model in order to model cement defects. The bilateral reduction of modulus by 40% in the cement adjacent to the distal portion of the prosthesis stem can lead to an increase of the strain energy density by 19%.
Metabolic Fate of 4,4′-Diaminodiphenylsiilfone (DDS) in the Rabbit and its Isolation from Urine

SummaryA method is described for the isolation and identification of 4,4′-diamino-diphenylsulfone (DDS) in the urine of rabbits. The method is based on the solubility of the hydrochloride of DDS in water and the relative insolubility of the base in water but its ready solubility in ethyl acetate.Up to 70% of the total diazotizable material excreted in the urine following oral administration of DDS to rabbits has been isolated as unchanged DDS. Not more than about 5% of the diazotizable material may be in an altered form, and this probably as conjugated DDS. Partition chromatography indicated that it was not the acetylated derivative of DDS.
An inverse approach to determine solute and solvent permeability parameters in artificial tissues.

This study presents a generic numerical model to simulate the coupled solute and solvent transport in tissue sections during addition and removal of chemical additives or cryoprotective agents (CPA; dimethylsulfoxide or DMSO). Osmotic responses of various tissue cells within the artificial tissue are predicted by the numerical model with three model parameters: Permeability of the tissue cell membrane to water (Lp), permeability of the tissue cell membrane to the solute or CPA (ω), and the diffusion coefficient of the solute or CPA in the extracellular space (D). By fitting the model results with published experimental data on solute/water concentrations at various locations within an artificial tissue, we were able to determine the permeability parameters of artificial tissue cells in the presence of 1.538 M DMSO. Lp and ω were determined at three different locations within the artificial tissue assuming a constant value of solute diffusivity (D = 1.0×10−9 m2/s). The best fit values of Lp ranged from 0.59×10−14 to 4.22×10−14 m3/N-s while ω ranged from 0 to 6.6×10−13 mol/N-s. Based on these values of Lp and ω, the solute reflection coefficient, σ = 1 − ω $$\bar v_{{\rm CPA}}$$ /L p ranged from 0.9923 to 1.0. The relative values of ω and σ suggest that the artificial tissue cells are relatively impermeable to DMSO (or ω≈0 and σ≈1.0). This observation was used to modify our model to predict the values of Lp and D assuming ω = 0 and σ = 1.0. The best fit values of Lp ranged from 640×10−14 to 2.1×10−14 m3/N-s while D ranged from 0.63×10−9 to 1.52×10−9 m2/s. The permeability parameters obtained in the present study represent the first such effort for artificial tissues.
Control of active sites in flocculation : concept of equivalent active sites

Abstract Flocculation and dispersion of solids are strong functions of the amount and conformation of the adsorbed polymer. Regions of dispersion and flocculation of solids with particular polymer molecules may be deduced from saturation adsorption data. The concept of "equivalent active sites" is proposed to explain flocculation and dispersion behavior irrespective of the amount or conformation of the adsorbed polymer. The concept has been further extended to study the selective flocculation process.
Outline of a matrix calculus for neural nets

The activity of a neural net is represented in terms of a matrix vector equation with a normalizing operator in which the matrix represents only the complete structure of the net, and the normalized vector-matrix product represents the activity of all the non-afferent neurons. The activity vectors are functions of a quantized time variable whose elements are zero (no activity) or one (activity). Certain properties of the structure matrix are discussed and the computational procedure which results from the matrix vector equation is illustrated by a specific example.
Variational Bayesian Inference Techniques

Milestones in sparse signal reconstruction and compressive sensing can be understood in a probabilistic Bayesian context, fusing underdetermined measurements with knowledge about low-level signal properties in the posterior distribution, which is maximized for point estimation. We review recent progress to advance beyond this setting. If the posterior is used as a distribution to be integrated over instead of merely an optimization criterion, sparse estimators with better properties may be obtained, and applications beyond point reconstruction from fixed data can be served. We describe novel variational relaxations of Bayesian integration, characterized as well as posterior maximization, which can be solved robustly for very large models by algorithms unifying convex reconstruction and Bayesian graphical model technology. They excel in difficult real-world imaging problems where posterior maximization performance is often unsatisfactory.
Model for CMOS/SOI single-event vulnerability

A lumped-parameter model derived from transistor characterization data has been used in SPICE analyses to study and predict the single-event-upset thresholds for SIMOX SOI (separation by implantation of oxygen, silicon-on-insulator) SRAMs (static random-access memories) with a variety of cell designs. The modeling of CMOS/SOI transistors with fully bottomed sources and drains includes direct representation of the parasitic lateral bipolar structure. Results indicate that, in the SOI devices investigated, single events simulate a localized bipolar response, even in devices with bodies electrically tied to active nodes. The bipolar response enhances the destabilizing effect of an ion event. The total current impulse contributing to upset can be significantly greater than that produced by direct ionization within the hit transistor, i.e., devices can be upset by ions that deposit less than the total charge required to initiate logic state reversal. In light of this, advanced CMOS/SOI-SOS logic with short channel lengths (and therefore significant parasitic bipolar gain) may exhibit critical LETs (linear energy transfers) lower than expected from simple scaling rules, and thinning of the active regions may not significantly reduce single-event rates in such CMOS/SOI digital circuits. >
Confounding psychosis in the postpartum period.

This case report alerts the psychiatric clinician to consider nonpsychiatric etiologies of psychosis appearing during the postpartum period besides postpartum psychosis. The case includes a description of the patient’s psychiatric presentation, admission to the inpatient psychiatric unit with subsequent transfer to the medicine department including neuroimaging and neurological consultation. The patient had a remission of psychosis after only two and half days of antipsychotic medication administration. Positive findings on the MRI suggested a demyelinating disease and a 4-month follow up MRI continued to be positive. The etiology was presumed to be a demyelinating disease. In conclusion, psychiatrists need to be alert to include nonpsychiatric pathologies in the differential diagnosis when a patient presents with psychosis in the postpartum period.
A randomized comparison of the efficacy of 2 techniques for piriformis muscle injection: ultrasound-guided versus nerve stimulator with fluoroscopic guidance.

Background Piriformis muscle injections are most often performed using fluoroscopic guidance; however, ultrasound (US) guidance has recently been described extensively in the literature. No direct comparisons between the 2 techniques have been performed. Our objective was to compare the efficacy and efficiency of fluoroscopic- and US-guided techniques. Methods A randomized, comparative trial was carried out to compare the 2 techniques. Twenty-eight patients with a diagnosis of piriformis syndrome, based on history and physical examination, who had failed conservative treatment were enrolled in the study. Patients were randomized to receive the injection either via US or fluoroscopy. Injections consisted of 10 mL of 1% lidocaine with 80 mg of triamcinalone. The primary outcome measure was numeric pain score, and secondary outcome measures included functional status as measured by the Multidimensional Pain Inventory, patient satisfaction as measured by the Patient Global Impression of Change scale, and procedure timing characteristics. Outcome data were measured preprocedure, immediately postprocedure, and 1 to 2 weeks and 3 months postprocedure. Results We found no statistically significant differences in numeric pain scores, patient satisfaction, procedure timing characteristics, or most functional outcomes when comparing the 2 techniques. Statistically significant differences between the 2 techniques were found with respect to the outcome measures of household chores and outdoor work. Conclusions Ultrasound-guided piriformis injections provide similar outcomes to fluoroscopically guided injections without differences in imaging, needling, or overall procedural times.
High-nuclearity iridium carbonyl clusters containing phenylgermyl ligands: synthesis, structures, and reactivity.

The reaction of Ir 4 (CO) 1 2 with Ph 3 GeH at 97 °C has yielded the new tetrairidium cluster complexes Ir 4 (CO) 7 -(GePh 3 )(μ-GePh 2 ) 2 [μ 3 -η 3 -GePh(C 6 H 4 )](μ-H) 2 (10) and Ir 4 (CO) 8 (GePh 3 ) 2 (μ-GePh 2 ) 4 (11). The structure of 10 consists of a tetrahedral Ir 4 cluster with seven terminal CO groups, two bridging GePh 2 ligands, an ortho-metallated bridging μ 3 -η 3 -GePh(C 6 H 4 ) group, a terminal GePh 3 ligand, and two bridging hydrido ligands. Compound 11 consists of a planar butterfly arrangement of four iridium atoms with four bridging GePh 2 and two terminal GePh 3 ligands. The same reaction at 125 °C yielded the two new triiridium clusters lr3(CO)5(GePh3)(μ-GePh 2 ) 3 (μ 3 -GePh)(μ-H) (12) and Ir 3 (CO)6(GePh3) 3 (μ-GePh2)3 (13). Compound 12 contains a triangular Ir 3 cluster with three bridging GePh 2 , one triply bridging GePh, and one terminal GePh 3 ligand. The compound also contains a hydrido ligand that bridges one of the Ir-Ge bonds. Compound 13 contains a triangular Ir 3 cluster with three bridging GePh 2 and three terminal GePh 3 ligands. At 151 °C, an additional complex, lr4H4(CO) 4 (μ-GePh2) 4 (μ 4 -GePh)2 (14), was isolated. Compound 14 consists of an Ir 4 square with four bridging GePh 2 , two quadruply bridging GePh groups, and four terminal hydrido ligands. Compound 12 reacts with CO at 125 °C to give the compound Ir 3 (CO) 6 (μ-GePh 2 ) 3 (μ 3 -GePh) (15). Compound 15 is formed via the loss of the hydrido ligand and the terminal GePh 3 ligand and the addition of one carbonyl ligand to 12. All compounds were fully characterized by IR, NMR, single-crystal X-ray diffraction analysis, and elemental analysis.
Heart Composite Material Model for Stress-Strain Analysis

Mechanical properties of the myocardium have been investigated intensively in the past four decades. Due to the non-linearity and history dependence of myocardial deformation, many complex strain energy functions have been used to describe the stress-strain relationship in the myocardium. These functions are good at fitting in-vitro experimental data from myocardial stretch testing into strain energy functions. However, it is difficult to model in-vivo myocardium by using strain energy functions. In a previous paper [1], we have implemented a transversely anisotropic material model to estimate in-vivo strain and stress in the myocardium. In this work, the fiber orientation is updated at each time step from the end of diastole to the end of systole; the stiffness matrix is recalculated using the current fiber orientation. We also extend our model to include residual ventricular stresses and time-dependent blood pressure in the ventricular cavities.Copyright © 2003 by ASME
Pension reforms and employment

The Chilean social security reform became effective in November 1980, replacing a traditional pay-as-you-go system with a unified system based on a minimum required contribution towards an individual account. The reform lowered the combined contribution rates towards old age and disability pension and tightened the link between contributions and benefits increasing individuals' valuation of contributions. This paper offers estimates of ‘money's worth’ ratios for ‘typical contributors’ before and after reform, indicating that the post-reform money's worth of each peso of contribution increased substantially for all groups, and particularly for women. Using aggregate data on employment and output from 1960 to 2002, estimates imply that a 10% reduction in the payroll tax led to a 2% increase in employment, and to a 0.7 point expansion in labour force participation.
Quando os afrodescendentes se tornaram “povos tribais” : o sistema interamericano de direitos humanos e as comunidades negras rurais

O sistema interamericano tem se estabelecido como um agente permanente e proeminente na discussao sobre a protecao dos direitos territoriais coletivos dos povos indigenas e dos afrodescendentes. Isso se confirma pela receptividade do sistema as demandas territoriais dos povos indigenas e afrodescendentes. A jurisprudencia interamericana, para reconhecer os direitos coletivos a propriedade, pressupoe e exige que os povos indigenas e certos povos afrodescendentes tenham uma relacao cultural exclusiva com suas terras tradicionais que os qualifiquem como “povos tribais”. Embora a utilizacao de um mecanismo judicial internacional para proteger esses direitos coletivos traga beneficios e oportunidades, existem tambem limitacoes quanto ao uso de uma estrategia de litigio fundada em uma abordagem cultural de territorio. Com o objetivo de analisar esses problemas e limitacoes, neste artigo enfoca-se um aspecto especifico das demandas que os povos indigenas e afrodescendentes tem levado ao sistema interamericano de direitos humanos nas ultimas decadas: reivindicacoes quanto a protecao das terras e territorios que eles tem tradicionalmente ocupado e dos recursos naturais nelas encontrados. Neste artigo procura-se responder as seguintes questoes: Que grupos permanecem excluidos do direito de fazer tais demandas? Sera que o sistema interamericano protege suficientemente os recursos naturais encontrados nos territorios tradicionais? Sera que essa abordagem cultural se antepoe a discriminacao estrutural enfrentada pelos afrodescendentes na America Latina?
The physiologic evaluation of stenosis by transthoracic Doppler: a bit of theory, a lot of practice.

Myocardial ischemia is the metabolic derangement that results when myocardial blood flow is insufficient to meet demand. Epicardial coronary artery disease that is moderate to severe, but not flow-limiting at rest, often produces a situation where ischemia occurs only when further increases in flow cannot meet increases in myocardial oxygen demand beyond resting conditions. The ‘‘unmasking’’ of this inadequacy of flow reserve in the clinical setting generally relies on exercise stress or inotropic drugs such as dobutamine that increase myocardial oxygen demand, or on the drugs that directly dilate the coronary resistance arterioles. These ‘‘stressors’’ are generally used in conjunction with methods that non-invasively image myocardial function (wall motion, strain) or regional perfusion. Abnormal flow reserve caused by epicardial stenosis or by conditions that alter microvascular function can also be detected invasively by measurement of coronary ‘‘flow’’ reserve (CFR). This measurement has traditionally been made at the time of angiography with a steerable intracoronary Doppler flow wire and intracoronary administration of a vasodilator such as adenosine. The word flow is in quotations because conventionally only coronary flow velocity is measured and coronary arterial diameter is not. Because of improvements in ultrasound technology and the advent of ultrasound contrast agents that augment spectral Doppler signals, it has become possible to detect epicardial flow responses in coronary artery disease non-invasively with transthoracic echocardiography. This approach has been shown to be possible not only for the left anterior descending (LAD) vessel, which is easily identified in the anterior interventricular sulcus, but also for the right and left circumflex arteries. It is also worth noting that while the use of epicardial Doppler to measure CFR is relatively new, CFR was the first method applied to evaluate the physiologic significance of stenosis by Gould et al in 1974. There are several common clinical scenarios that justify the evaluation of epicardial CFR, either invasively or non-invasively. The physiologic significance of a stenosis can be in question when intermediate-severity disease is discovered in patients referred for angiography without preceding stress imaging. CFR has also been used to assess ‘‘incidental’’ disease that is found in vessels other than those of primary concern in patients undergoing catheterization due to acute coronary syndrome or positive stress imaging. In these settings, rapid assessment of CFR can be used to make a decision on coronary intervention while the patient is still in the angiography suite. Assessment of CFR may also be useful when, despite high clinical suspicion
The effects of channel correlation on maximal ratio combining performance in the presence of cochannel interferers

In this paper, we analyze the effects of channel correlation on the performance of maximal ratio combining (MRC) in receive antenna diversity systems. In the analysis, the channel is modelled as flat Rayleigh fading, slowly varying and an arbitrary number of cochannel interferers are assumed to be present. In an interference limited scenario, an exact closed form expression for signal to interference ratio (SIR) distribution is obtained for a dual antenna system. The degradation in the outage probability as a function of the correlation severity is investigated.
Sound source detection threshold estimation using negative coherent power

This paper introduces a method for automatic detection and location of sound sources using distributed microphones in conjunction with a steered response power (SRP) algorithm. In many practical sound source location applications, sources must be automatically detected for computer driven analyses of the auditory scene. The method introduced in this paper takes advantage of the near-symmetric noise distribution of the coherent power resulting from the cross-correlations between microphone pair signals; autocorrelation components, which are included in the conventional SRP image, are removed resulting in positive and negative image values (referred to as coherent power). Thresholds applied to the positive coherent power values are estimated adaptively using local neighborhoods of negative coherent power values to achieve a constant false alarm rate (CFAR). In order to ensure sufficient symmetry, this paper derives a statistic based on the microphone geometry and the field of view (FOV) that is useful for determining source frequency ranges that result in effective zero-mean symmetric distributions necessary for an accurate CFAR threshold estimation. Experimental results for several microphone geometries are presented to assess the CFAR threshold accuracy. False-alarm probabilities are tested over a range from 102 and 106 and error computed in terms of the experimentally assessed FA probability to the specified FA probability. Results show good agreement between the microphone geometry statistic and the relative performance of the CFAR thresholds. The best performing geometry achieved a false-alarm rate error of 16% (at 106) when a Weibull distribution model was used for CFAR threshold estimation.
USE OF HYDRAULIC MODELLING TO ASSESS PASSAGE FLOW CONNECTIVITY FOR SALMON IN STREAMS

The maintenance of hydrologic connectivity in river networks has become an important principle for guiding management and conservation planning for threatened salmon populations, yet our understanding of how fish movement is impaired by spatial and temporal variation in connectivity remains limited. In this study, a two-dimensional hydraulic modelling approach is presented to evaluate flow connectivity in relation to passage requirements of adult steelhead trout (Oncorhynchus mykiss) in coastal California streams. High-resolution topographic data of stream reaches with distinct channel morphology were collected using terrestrial light detection and ranging surveys and linked with water surface measurements to calibrate hydraulic model simulations. Quantitative metrics of longitudinal flow connectivity were developed to assess fish passage suitability in relation to stream discharge. Measured flow data from the 2008–2009 winter season and simulated long-term records indicated that suitable passage flows occur with relatively low frequency and duration at all sites, suggesting that instream flow protections for fish passage are warranted. Results from the hydraulic modelling simulations were then compared with two alternative methods for assessing passage flows. A regional formula used by the State of California to identify minimum instream flow needs provided conservative estimates of passage flow requirements, whereas an approach based on riffle crest water depths underestimated flow needs. The hydraulic modelling approach appears well suited for simulating flows for fish passage studies and may be particularly useful for testing alternative environmental flow assessment methods and evaluating habitat–flow relationships in stream reaches of importance, such as critical habitat for threatened fish species. Copyright © 2011 John Wiley & Sons, Ltd.
Exploring the Effect of Reservoir Storage on Peak Discharge Frequency

AbstractIn this paper, a simple hydrologic example is employed to illustrate the important features of reservoir regulated flood frequency. Despite its practical significance, the estimation of reservoir regulated flood frequency is largely dominated by empirical methodologies containing assumptions that could lead to incorrect results. The goal of this paper is to show by means of a continuous rainfall-runoff simulation how several reservoir variables, including the reservoir storage capacity, the size of release structures, operation rules, and the statistical variability of inflows to the reservoir, quantitatively control the regulated flood frequency. Although the example presented in this paper does not encompass the full complexity of the problem, it reveals important features of the regulated flood frequency. The study also highlights how specific assumptions in the traditional and widely used inflow volume-duration-frequency (VDF)–based methodology could lead to underestimation of flood risk for l...
Three-Dimensional Wind-Driven Coastal Circulation past a Headland

Local velocities and the trajectories of fluid parcels forced by wind blowing over a continental shelf, in the vicinity of a headland, are described with a linear, steady, three-dimensional barotropic model. The dynamical balance that governs the transport is similar to the wind-driven general circulation, because the varying bottom depth acts in the same way as meridional variation in the rotation rate. Far from the headland the circulation is independent of alongshore position, and the transport is parallel to the coast. The alongshore pressure gradient is a significant term in the alongshore momentum balance. Near the headland, the amplitude of the circulation, including the vertical motion, is larger on the upwave side (the side toward which a Kelvin wave would travel) than on the downwave side. On the upwave side, the flow adjusts to the presence of the headland over a distance of order EB*, where E is the ratio of the Ekman depth to the maximum shelf depth and B* is the width of the shelf. Fluid parcels that upwell on the upwave side are drawn from deeper depths than parcels that upwell at other alongshore locations. On the downwave side the flow adjusts over a relatively long distance, of order 1 E B*.
Use of ELISA to monitor bacterial kidney disease in naturally spawning chinook salmon

Bacterial kidney disease (BKD) caused by Renibacterium salmoninarum (Rs) is a serious problem among Pacific Northwest salmon hatcheries and has raised concerns that salmon reared in hatcheries may spread BKD to natural populations. In order to monitor the potential spread of this dis- ease to salmon spawning in nature, a method must be available to collect and analyze tissues from naturally spawning salmon. Kidney tissue analyzed by enzyme-linked immunosorbent assay (ELISA) is the standard method to detect the presence of Rs in salmon sampled in hatcheries. In this study, we tested the validity of using ELISA on kidney tissue collected from intact carcasses recovered on the spawning grounds to monitor BKD in naturally spawning populations by comparing ELISA optical density (OD) values from kidney tissue that was subjected to conditions that simulated decomposition in a carcass and collection during a spawning ground survey with samples freshly collected from salmon at a hatchery. Mean ELISA OD levels were 1.060 for the samples prepared by the normal preparation and 1.115 for samples prepared by simulating spawning ground survey collection. There was no significant difference in mean ELISA OD between the 2 sample preparations and the relation- ship did not significantly differ from 1:1 (slope = 0.946). This demonstrates that BKD prevalence in natural populations can be monitored using ELISA conducted on samples from intact carcasses recovered on spawning ground surveys. This will be an important tool for monitoring the effect of hatchery supplementation on naturally spawning salmon populations.
Differential Involvement of Th1 and Th17 in Pathogenic Autoimmune Processes Triggered by Different TLR Ligands

The interaction between TLRs and their cognate ligands triggers both the innate and adaptive immune systems, and thus can play a pivotal role in the defense against pathogen invasion. This work investigates the differentiation of naive CD4 cells into Th1 or Th17 phenotypes in mice treated with different TLR ligands. We use a model system in which naive transgenic cells specific to hen egg lysozyme are adoptively transferred into recipients that express hen egg lysozyme in the lens of the eye. The transferred naive T cells induce ocular inflammation only in recipients treated with TLR ligands. Treatment with LPS preferentially stimulated IL-17 production, whereas CpG oligodeoxynucleotide and polyinosinic:polycytidylic acid primarily stimulated Th1 cells. Peptidoglycan stimulated the two Th subpopulations equally. The preferential induction of Th1 or Th17 by the four ligands was detected in the spleen (where a major portion of the adoptively transferred cells homed) and in the eyes, where activated Th cells initiate inflammation. Analysis of the cytokines present in recipient mice suggests that Th1 induction is elicited by IL-12 and/or IFN-α, whereas Th17 generation is preferentially mediated by IL-6. Importantly, we show in this article that treatment with LPS selectively promoted in the recipient mice the generation of IL-6-producing activated B cells. An inverse correlation was found between the level of regulatory T cells and severity of inflammation induced by the donor cells. Taken together, our data show that specific TLR ligands differentially activate the immune system as evidenced by the generation of distinct Th phenotypes from naive CD4 cells.
PLANT TRAITS THAT INFLUENCE ECOSYSTEM PROCESSES VARY INDEPENDENTLY AMONG SPECIES

Most predictions of plant species effects on ecosystems are based on single traits (e.g., litter chemistry) or suites of related traits (functional groups). However, recent studies demonstrate that predictions of species effects on ecosystems are improved by considering multiple traits. In order to develop this multiple trait approach, it is critical to understand how these multiple traits vary in relation to one another among species. The ecosystem effects of traits that strongly covary can likely be summarized by one of these traits. In contrast, it will be necessary to determine the ecosystem effects of specific trait combinations for those traits that vary independently across species. In the field, I established monocultures of eight herbaceous species common in California annual grasslands. Plant species significantly differed in their litter quantity and quality, live biomass, and effects on soil labile C, soil temperature, and soil moisture. Species effects on soil moisture and temperature were only significant at the times of the growing season when each of these limited plant and microbial activity. Some of these traits cor- related with one another, such as litter biomass and species effects on soil temperature during the winter. However, for the most part, plant species exhibited unique combinations of these traits. For example, species with similar litter chemistry had the largest differences in plant biomass, soil moisture, and soil labile C. Species rankings for many traits changed over the growing season (e.g., biomass), so that the relationship among traits varied sea- sonally. The independent variation of these traits suggests that predictions of plant species effects on ecosystems will likely be enhanced by an understanding of how the ecosystem effects of plant traits may vary depending on the combination of traits.
A Political Explanation for Exchange-Rate Regime Gaps

Why do certain governments often have an actual exchange-rate policy that differs from their official declaration, creating a gap between their de jure and de facto exchange-rate regimes? This article offers a political explanation centered on the need for certain types of government to respond to a broader set of societal actors with different preferences concerning the exchange-rate regime. The argument posits that more democratic governments must respond to a broader set of societal actors, thus leading them to use their de jure and de facto regimes as short-term political substitutes. In using one regime (either de jure or de facto) to appeal to one group of societal actors and the other regime to appeal to another group with different preferences, exchange-rate regimes are hypothesized to be more frequent for more democratic governments. The statistic evidence accords with this expectation.
Simulating the dispersal of hemlock woolly adelgid in the temperate forest understory

Thehemlock woollyadelgid(HWA),Adelges tsugaeAnnand(Hemiptera:Adelgidae),has spreadrap- idly across the eastern USA since its introduction from Japan 60 years ago, causing widespread mor- tality of both eastern hemlock (Tsuga canadensis (L.) Carriere) and Carolina hemlock (Tsuga caroliniana Engelm. (Pinaceae)). Although HWA spread patterns have been repeatedly analyzed at regional scales, comparatively little is known about its dispersal potential within and between hem- lock stands. As the small size and clonal nature of HWA make it nearly impossible to identify the source populations of dispersing individuals, we simulated intra-stand HWA movement in the field by monitoring the movement ofclumps offluorescent powder that areslightly larger than HWA,but much easier to detect in the forest understory. Using three hemlock trees with three colors offluores- cent powder as source populations, we detected dispersal events at the farthest distances within our trappingarray (400 m).However, more than 90% ofdispersal events were <25 m. Dispersal patterns were similar from allthree source treesand the distribution ofdispersal distances in allcasescouldbe described by lognormal probability density functions with mean dispersal distance of 12-14 m, sug- gesting that dispersal was relatively independent of location of source trees. In general, we docu- mentedtensofthousandsofpassivedispersal events intheforest understory despite thepresenceofa dense forest canopy. Thus, even under relatively light-wind conditions, particles of similar dimen- sions to HWA are capable of intra-stand movement, suggesting that a large population of HWA couldrapidly infest othertreeswithinseveralhundredmeterradius, orbeyond.
Treatment of Tick-Borne Diseases

OBJECTIVE:To review the data regarding the pharmacotherapy of Lyme disease, Rocky Mountain spotted fever (RMSF), and the human ehrlichioses.DATA SOURCES:English-language literature was identified via MEDLINE (1966–January 2002) using the keywords Lyme disease, Rocky Mountain spotted fever, and ehrlichiosis. Textbooks and other pertinent resources were also reviewed.STUDY SELECTION AND DATA EXTRACTION:All articles identified through the data sources above were evaluated and reviewed if pertinent to the objective.DATA SYNTHESIS:Tick-borne diseases are the most common vector-transmitted diseases in North America. Each disease causes significant morbidity and, in the case of RMSF, mortality if patients go untreated. If the disease syndromes are recognized early and treatment is initiated, complications are greatly reduced. Doxycycline is active against each of the causative organisms, simplifying empiric treatment.CONCLUSIONS:Effective pharmacotherapy exists to treat each of these diseases, assuming diagnosis...
Political Irrelevance, Democracy, and the Limits of Militarized Conflict

Although the statistical literature on conflict studies has generated strong and consistent findings on the relationship of political irrelevance and dyadic democracy to conflict, scholars have paid scant attention to the interesting theoretical issue of how they matter. The authors argue that additive controls and dropping irrelevant dyads constitute misspecifications of their effects. There are theoretical reasons to believe that the impact of distance on conflict is not sufficiently severe to justify the practice of simply dropping irrelevant dyads. Moreover, they argue that political irrelevance and dyadic democracy, rather than subtracting some constant quantity, interact to impose an upper bound on the probability of conflict initiation. They find both of these arguments to be supported in a reanalysis of a prominent study of dispute initiation.
Thymosin beta 4 induces hair growth via stem cell migration and differentiation

Thymosin beta 4 is a small 43-amino-acid molecule that has multiple biological activities, including promotion of cell migration angiogenesis, cell survival, protease production, and wound healing. We have found that thymosin beta 4 promotes hair growth in various rat and mice models including a transgenic thymosin beta 4 overexpressing mouse. We have also determined the mechanism by which thymosin beta 4 acts to promote hair growth by examining its effects on follicle stem cell growth, migration, differentiation, and protease production.
Time‐dependent rheological properties and transient structural states of entangled polymeric liquids—A kinetic network model

A kinetic network model has been developed to describe the nonlinear rheological behavior of entangled polymer solutions and melts in either steady-state or transient flows. This model is based on the concept of flow-induced structure variation, controlled by the simultaneous existence of entanglement loss and regeneration. When steady-state is attained, both processes occur at the same rate and the structural state (entanglement density) of the fluid remains constant with time. Under transient flow conditions, the fluid structure becomes time-dependent as a result of unequal rates of the two competing processes affecting entanglement density. The viscoelastic response of the fluid is, in turn, influenced by the varying structural state. This is incorporated into the model through the use of structure-dependent coefficients in the contravariant Maxwell constitutive equation for entanglement stress. Model predictions are generated for a number of transient flow programs, including the stress growth and relaxation, interrupted flow, sudden change in shear rate, and nonlinear creep experiments. Comparison with literature data supports not only the qualitative success but also the quantitative ability of this model.
On the utility of in situ soil moisture observations for flash drought early warning in Oklahoma, USA

Drought early warning systems are a vital component of drought monitoring and require information at submonthly time scales because of the rapidly evolving nature of drought. This study evaluates the utility of in situ soil moisture observations for drought early warning in Oklahoma. Soil moisture was used to identify drought events, and the results were compared with the U.S. Drought Monitor with respect to the identification of drought onset. Soil moisture observations consistently identify rapid-onset (flash) drought events earlier than the U.S. Drought Monitor. Our results show that soil moisture percentiles provide a 2–3 week lead time over the U.S. Drought Monitor based on five flash drought events that occurred in Oklahoma between 2000 and 2013. We conclude that in situ soil moisture observations are an important source of information for early warning of flash drought events in the Oklahoma.