cssi/SciSciGPT-SciSciNet huggingface dataset:
Localized electrons and phonon-induced laser cooling of solids

Under appropriate conditions absorption of light by a solid can initiate a process by which it is cooled. Here, two schemes for laser cooling via localized electrons are addressed. The first scheme utilizes two states of a localized center. In this two-level scheme, the cooling process is initiated with photon absorption in the low-energy tail of a localized state's strain-broadened absorption spectrum. The subsequent atomic relaxation transfers energy of especially large vibratory atomic strains into electrical energy that is then extracted via photon emission. Cooling can occur at elevated temperatures but is suppressed as the temperature is lowered. The second scheme involves three energy levels of a localized center. Cooling is facilitated when i) the photo-excitation of an electron promotes it to the lower of the two upper levels followed by ii) its electron-phonon-induced promotion to the upper-most level and the subsequent iii) return of the electron to its initial state via emission of a photon of higher energy than that of the absorbed photon. However, competing relaxation processes contribute to heating. The net cooling power is calculated. Heating predominates at low temperatures. Significant cooling at elevated temperatures requires satisfying very restrictive conditions. Among these: i) the energy separation between two highest states must be very small; ii) the degeneracy of the highest state must exceed that of the state below it, and; iii) the effective electron-phonon interaction, responsible for energy levels' Stokes shifts, must be exceptionally weak. Different avenues to promising systems to achieve laser cooling are identified.
A model for heterogeneity of kinetics of albumin transport in the renal cortical interstitium

Abstract A model is proposed for the kinetics of the albumin pool of the renal cortical interstitium. The interstitial albumin pool is assumed to consist of a large ensemble of subunits, each of which acts as a single well-mixed compartment. The turnover rate constants are assumed to be statistically distributed over subunits according to the Gamma distribution. The resulting model allows estimation of both the mean and the variance of the distribution of rate constants within a kidney from experimental measurements of albumin specific activity in arterial plasma and renal lymph. The fit of this model to experimental data was found to be better than that of a single well-mixed compartment. Results are shown for normal rats, rats under physiological stress (hydration), and rats with a pathological condition (diabetes). An increased heterogeneity of the within kidney turnover rates was indicated under both conditions of stress and pathology.
Profit Prediction in Cow/Calf Operations: Part 2, Influence of Major Management Practices

Determining which management practices to focus on to improve profitability is a major challenge in any cow/calf operation. We used CowCost management simulation to evaluate the relative importance the major factors. The software generated 50 000 different management scenarios using values that were generated randomly, but within reasonable ranges of typical western cow/calf operations. Management factors studied by the model included the original cost of the cow, interest rate paid on money borrowed to buy the cow, salvage value of the cow at the end of her production life, percentage of calves the cow might wean, yearly cost per cow of the ranching operation, average weaning weight of the calf, and the average price brought by the calf. The model assumes calves will be sold at weaning and not held as yearlings. The model used these management factors to predict profit or loss, and to gauge the relative importance of the management practice. All scenarios were for one cow with an assumed production of 8 yr. Correlation analysis of the data showed that yearly cost was the most influential in determining profit or loss. The money received per pound of calf was next most influential. Weaning weight was the third most influential and weaning percent is fourth. The original cost of the cow, interest rates, and salvage value of the cow were far less influential on profit loss. While these final items, especially the cost of the cow and interest rate, receive a great deal of attention from most producers, they may not deserve that much attention, especially compared with other management inputs.
Conduction system in congenital heart disease

Abstract The conduction system in congenital heart disease may show abnormalities in position, disruption in continuity, or accessory or abnormal communications. Complete or partial A-V block, right bundle branch block and Wolff-Parkinson-White syndrome may be related to these abnormalities. In addition, there may be many other electrocardiographic abnormalities which may be explained by already described or as yet undescribed aberrations in the conduction system.
Intravital Imaging of Axonal Interactions with Microglia and Macrophages in a Mouse Dorsal Column Crush Injury

Traumatic spinal cord injury causes an inflammatory reaction involving blood-derived macrophages and central nervous system (CNS)-resident microglia. Intra-vital two-photon microscopy enables the study of macrophages and microglia in the spinal cord lesion in the living animal. This can be performed in adult animals with a traumatic injury to the dorsal column. Here, we describe methods for distinguishing macrophages from microglia in the CNS using an irradiation bone marrow chimera to obtain animals in which only macrophages or microglia are labeled with a genetically encoded green fluorescent protein. We also describe a injury model that crushes the dorsal column of the spinal cord, thereby producing a simple, easily accessible, rectangular lesion that is easily visualized in an animal through a laminectomy. Furthermore, we will outline procedures to sequentially image the animals at the anatomical site of injury for the study of cellular interactions during the first few days to weeks after injury.
Laparoscopic cholecystectomy produces less postoperative restriction of pulmonary function than open cholecystectomy.

This study was undertaken to determine whether laparoscopy produces less postoperative decrease in pulmonary function than does open operation.
The first successful repair of postinfarction ventricular septal defect: influence of good fortune, team work, and an inquisitive mind

Research in our institution identified the first case in which cardiopulmonary bypass was utilized. By happenstance, it turned out to be the presumed first repair of postinfarction ventricular septal defect. The circumstances of this interesting case are presented and discussed in the context of our surgical heritage.
The Testing of Brushes for Life and Performance Under Various Altitude Conditions

This paper presents the author's experience in the testing of brushes on machines intended for high-altitude service on aircraft equipment. The procedure and range of conditions found useful in testing a wide variety of small a-c and d-c machines are outlined in detail. It is hoped that other investigators will contribute their experiences through discussions or additional papers, and that from this material there may be developed a suitable test code, supplementing the present Institute test code for d-c machines. The only real criterion of brush performance is that of actual experience in service, since all of the infinite variety of conditions that affect brush performance cannot be anticipated under test conditions. However carefully conducted tests over a range of specified conditions do provide a good basis for brush selection and greatly expedite the final choice for the best over-all performance. For this reason, and because it will be helpful to investigators in comparing their results, it is hoped that the proposed brush test code may be undertaken in the near future.
Using Regression Tree Analysis to Improve Predictions of Low-Flow Nitrate and Chloride in Willamette River Basin Watersheds

The use of regression tree analysis is examined as a tool to evaluate hydrologic and land use factors that affect nitrate and chloride stream concentrations during low-flow conditions. Although this data mining technique has been used to assess a range of ecological parameters, it has not previously been used for stream water quality analysis. Regression tree analysis was conducted on nitrate and chloride data from 71 watersheds in the Willamette River Basin to determine whether this method provides a greater predictive ability compared to standard multiple linear regression, and to elucidate the potential roles of controlling mechanisms. Metrics used in the models included a variety of watershed-scale landscape indices and land use classifications. Regression tree analysis significantly enhanced model accuracy over multiple linear regression, increasing nitrate R 2 values from 0.38 to 0.75 and chloride R 2 values from 0.64 to 0.85 and as indicated by the ΔAIC value. These improvements are primarily attributed to the ability for regression trees to more effectively handle interactions and manage non-linear functions associated with watershed heterogeneity within the basin. Whereas hydrologic factors governed the conservative chloride tracer in the model, land use dominated control of nitrate concentrations. Watersheds containing higher agricultural activity did not necessarily yield high nitrate concentrations, but agricultural areas combined with either small proportions of forested land or greater urbanization generated nitrate levels far exceeding water quality standards. Although further refinements are recommended, we conclude that regression tree analysis presents water resource managers a promising tool that improves on the predictive ability of standard statistical methods, provides insight into controlling mechanisms, and helps identify catchment characteristics associated with water quality impairment.
The Effect of Context on Nursing Student Math Aptitude

Math proficiency is a prerequisite to the performance of many nursing functions, including medication calculations, but many nursing students have difficulty performing this basic clinical skill. Research has demonstrated that math aptitude alone does not fully explain student outcomes on medication calculation assessments (MCAs), and contextual factors associated with reading and interpreting written medication questions are important for nurse educators to better understand. Reading and English aptitude are proposed as two potential contextual factors that may help explain the nursing student's ability to pass a written MCA. The purpose of this study was to describe the effects of reading and English aptitude on baccalaureate nursing students' ability to pass an MCA taken during the junior year of the nursing curriculum.
The electrophoretic nature of human amylase and the effect of protein on the starch-iodine reaction.

Abstract Conflicting reports have appeared in the literature regarding the electrophoretic behaviour of human serum amylase. The difference in results has probably been due to the diverse methods used. The present work describes a saccharogenic method for the assay of amylase in the various fractions of serum obtained by electrophoresis on paper and in polyacrylamide gel. The effect of albumin and γ-globulin on the blue colour of the starch-iodine reaction is also described. The results obtained indicate that on electrophoresis the amylase of human serum migrates only with the γ-globulin fraction, and that previous results obtained by some workers using amyloclastic methods for investigating this subject are invalid.
Finding an Inner Voice through Silence: Mindfulness Goes to College

College students are stressed. This is not news. However, the increasing level of stress and anxiety they report is alarming. Added to the traditional pressures to fit in, succeed, and mature, toda...
Heat-Induced Changes in the Finite Strain Viscoelastic Behavior of a Collaagenous Tissue

Supra-physiological temperatures are increasingly being used to treat many different soft tissue diseases and injuries. To identify improved clinical treatments, however, there is a need for better information on the effect of the mechanics on the thermal damage process as well as the effect of the incurred damage on the subsequent mechanical properties. In this paper, we report the first biaxial data on the stress relaxation behavior of a collagenous tissue before and after thermal damage. Based on a two-dimensional finite strain viscoelastic model, which incorporates an exponential elastic response, it is shown that the thermal damage can significantly decrease the characteristic time for stress relaxation and the stress residual.
Numerical Simulation of SEU Induced Latch-Up

The PISCES-II device analysis program has been modified to perform two-dimensional SEU induced latch-up simulations. The results of the simulations have been compared to cyclotron test data taken on a custom test chip. The comparison indicates that the simulations are accurate for light ions. A description of the latch-up process is also given.
Regulation of glutamine and pyruvate oxidation in cultured adrenocortical cells by cortisol, antioxidants, and oxygen: Effects on cell proliferation

The regulation of CO2 production from [U-14C]glutamine and C2 of [2-14C]pyruvate was investigated in cultured bovine adrenocortical cells, and the effect of alterations in the relative rates of oxidation of these substrates on cell proliferation, particularly in the presence of an inhibitor of transamination reactions, was examined. 14CO2 production from 2 mM [U-14C]glutamine and 2 mM [2-14C]pyruvate was measured in the presence of 100 microM 2,4-dinitrophenol, an uncoupler of oxidative phosphorylation. Treatment of primary cultures of 24 h with 50 microM cortisol increased the oxidation of [14C]glutamine relative to that of [14C]pyruvate, an effect dependent on prior low cell density. Cortisol treatment also resulted in a prolonged delay in the onset of proliferation from low density, and completely inhibited growth in the presence of 2 mM aminooxyacetate, which reduces mitochondrial utilization of glutamine. The effects on glutamine and pyruvate metabolism and on cell growth, with or without aminooxyacetate, were prevented by simultaneous treatment with the antioxidants dimethyl sulfoxide (10 mM) and butylated hydroxyanisole (100 microM), suggesting the involvement of lipid peroxidation in the action of cortisol, as previously demonstrated for its action on 11 beta-hydroxylase. During continued proliferation of adrenocortical cells in the absence of cortisol there was also a slower increase in the oxidation of [14C]glutamine relative to that of [14C]pyruvate as a function of population doubling level. The rate of this increase was slowed by growth of cells in 2% O2 rather than the standard 19% O2, and accelerated by continued growth of cells in the presence of cortisol. The rate of increase in the oxidation of [14C]glutamine relative to that of [14C]pyruvate under these three conditions correlated with inhibition of cell growth by aminooxyacetate. In contrast to the complete inhibition of growth in aminooxyacetate demonstrated by cortisol-treated cells, control cells (19% O2) did proliferate, although growth was limited, whereas cells at 2% O2 proliferated to a much greater extent. In the absence of aminooxyacetate the rate of growth in primary adrenocortical cell cultures under these three conditions was similar. Lipid peroxidation appears to make cultured adrenocortical cells dependent on glutamine for mitochondrial function and proliferation by inhibiting the utilization of the normal substrate, pyruvate.
Association study of the CNR1 gene exon 3 alternative promoter region polymorphisms and substance dependence

An alternative promoter producing a novel 5′-untranslated region of cannabinoid receptor mRNA has recently been described in CNR1, the gene encoding the cannabinoid receptor protein. Single nucleotide polymorphisms (SNPs) adjacent to this site were reported to be associated with polysubstance abuse [Zhang et al., 2004]. We examined the association of 4 SNPs (rs6928499, rs806379, rs1535255, rs2023239) in the distal region of intron 2 of CNR1 both with individual substance dependence diagnoses (i.e., alcohol, cocaine, and opioids), as well as with polysubstance dependence. The study samples consisted of European-American (EA) and African-American (AA) subjects with drug and or alcohol dependence (n = 895), and controls (n = 472). Subjects were grouped as polysubstance dependent, opioid dependent, cocaine dependent, cannabis dependent, and alcohol dependent. There was a modest association of marker rs1535255 with alcohol dependence (P = 0.04), though with correction for multiple phenotype comparisons, this effect was not considered statistically significant. These findings fail to replicate the original report of an association between SNPs adjacent to an alternative CNR1 exon 3 transcription start site and polysubstance abuse. © 2006 Wiley-Liss, Inc.
The ciD mutation encodes a chimeric protein whose activity is regulated by Wingless signaling.

The Drosophila cubitus interruptus (ci) gene encodes a sequence-specific DNA-binding protein that regulates transcription of Hedgehog (Hh) target genes. Activity of the Ci protein is posttranslationally regulated by Hh signaling. In animals homozygous for the ciD mutation, however, transcription of Hh target genes is regulated by Wingless (Wg) signaling rather than by Hh signaling. We show that ciD encodes a chimeric protein composed of the regulatory domain of dTCF/Pangolin (Pan) and the DNA binding domain of Ci. Pan is a Wg-regulated transcription factor that is activated by binding of Armadillo (Arm) to its regulatory domain. Arm is thought to activate Pan by contributing a transactivation domain. We find that a constitutively active form of Arm potentiates activity of a CiD transgene and coimmunoprecipitates with CiD protein. The Wg-responsive activity of CiD could be explained by recruitment of the Arm transactivation function to the promoters of Hh-target genes. We suggest that wild-type Ci also recruits a protein with a transactivation domain as part of its normal mechanism of activation.
Erythroblastic Sarcoma, An Extremely Rare Variant of Myeloid Sarcoma.

A 79-year-old man was admitted to the hospital because of a 20-lb weight loss, low back pain, and leg weakness. He had a 1-year history of fibrotic myelodysplasia, possibly therapy related, with a highly complex chromosome karyotype. Radiologic evaluation showed extensive destructive bone lesions, retroperitoneal lymphadenopathy, and evidence for thoracic spinal cord compression. Core biopsies of a retroperitoneal lymph node showed groups of large, immature-appearing mononuclear cells which, on Wright-stained touch preparation, appeared similar to dysplastic erythroid precursors noted on recent marrow aspirate smears. Immunohistochemical staining showed negativity of neoplastic cells to an extensive panel of nonhematopoietic and myeloid markers, and positivity for CD117, glycophorin A, and CD71, consistent with a diagnosis of erythroblastic sarcoma. This lesion is a very unusual variant of myeloid sarcoma and has been described only rarely in the medical literature.
Optimization of simulation models using successive quadratic approximations

Abstract In this paper the development of a search procedure, successive quadratic approximations, and its application to the optimization of systems modeled through simulation are presented, where the measure of system performance is cost. Since random error is usually inherent in simulation, and since replication is one means of reducing the effect of random error, the number of replications required to estimate the measure of system effectiveness at each point evaluated in the search is specified in conjunction with statistical criteria which may be assigned by the user. The search is terminated when specified statistical tests indicate that continuation of the search is likely to improve the system less than the cost of computer time for the next iteration, that is, when a point of diminishing returns is reached.
A geometric approach to multi-view compressive imaging

In this paper, we consider multi-view imaging problems in which an ensemble of cameras collect images describing a common scene. To simplify the acquisition and encoding of these images, we study the effectiveness of non-collaborative compressive sensing encoding schemes wherein each sensor directly and independently compresses its image using randomized measurements. After these measurements and also perhaps the camera positions are transmitted to a central node, the key to an accurate reconstruction is to fully exploit the joint correlation among the signal ensemble. To capture such correlations, we propose a geometric modeling framework in which the image ensemble is treated as a sampling of points from a low-dimensional manifold in the ambient signal space. Building on results that guarantee stable embeddings of manifolds under random measurements, we propose a "manifold lifting" algorithm for recovering the ensemble that can operate even without knowledge of the camera positions. We divide our discussion into two scenarios, the near-field and far-field cases, and describe how the manifold lifting algorithm could be applied to these scenarios. At the end of this paper, we present an in-depth case study of a far-field imaging scenario, where the aim is to reconstruct an ensemble of satellite images taken from different positions with limited but overlapping fields of view. In this case study, we demonstrate the impressive power of random measurements to capture single- and multi-image structure without explicitly searching for it, as the randomized measurement encoding in conjunction with the proposed manifold lifting algorithm can even outperform image-by-image transform coding.
Accelerator Physics Studies for the SSC

In the spring of 1984, a reference designs study (RDS) was carried out to identify the issues and to provide a crude cost estimate of the SSC. Following the RDS, a Central Design Group was formed in October to perform the detailed design RandD for construction of the SSC. This paper is a brief review of progress made on the accelerator physics studies since October 1984. For major issues not discussed here, many of them of great importance, the RDS report is still the valid source of information.
Access revocation and prevention of false repudiation in secure email exchanges

A secure email protocol (SEP) is introduced to provide a decentralized means of revoking trust access and preventing false repudiation. Verification of the exchange of a message between sender and recipient is accomplished through an identification cookie (IC) and an encryption key (EK) handled by Verification and Authentication Agents (VAAs). The communicated narrative is encrypted by the EK. The augmented message is then encrypted again using one of the widely available encryption algorithms, such as the Pretty Good Privacy (PGP) scheme, and sent to the addressee. The extracted IC serves as a label which the addressee uses to obtain the EK from the sender's VAA. Once the addressee possesses the message's EK, s/he is able to decrypt the narrative, verify that the IC is correct, and the process is complete. Quick revocation of access privileges and cancellation of old messages is achieved by deleting ICs not requested by the addressee. The structure of the message body is written in the eXtensive Markup Language (XML) to take advantage of the language's extendibility and compatibility features.
Aerosol probes of lung injury in a 28-wk longitudinal study of mild experimental emphysema in dogs

After baseline measurements of lung mechanics, effective air space diameter (EAD), and aerosol dispersion (AD), three dogs were exposed to two treatments of aerosolized papain (3 ml of a 4% solution), and measurements were repeated during a 28-wk follow-up period. EAD and AD were measured with boluses of 0.7-μm particles of di-2-ethylhexl sebacate, with Pen (i.e., volumetric bolus penetration/total lung capacity) between 0.1 and 0.4. After papain exposure, EAD increased a mean of 28% ( P < 0.0001) and AD (Pen = 0.3, 0.4) increased 4–7% ( P < 0.03). The progression of injury was indicated by increasing trends in total lung capacity ( P < 0.05), residual volume ( P < 0.05), and EAD ( P = 0.06) through week 18 . There was no evidence of disease progression between weeks 18 and 28 , whereas some of the data for individual dogs suggested partial recovery from lung injury at week 28 . The results show that aerosol probes can detect and characterize mild lung injury in experimental emphysema.
Introduction To "Stabilized Feed-Back Amplifiers"

Harold L. Black’s Classic Paper “Stabilized Feed-Back Amplifiers” appeared five years after he invented the feedback amplifier and four years before the patent was finally issued. Black’s paper shows the advantages of negative feedback in reducing harmonic distortion, increasing the bandwidth, and maintaining robust performance using primitive vacuum tubes. It also introduces a nomogram similar to the well-known Nichols Chart. In an effort to gain a better understanding of the unerlying mechanism of feedback, he enlisted the aid of H. Nyquist who responded with his famous paper, “Regeneration Theory.”
Genome-Based Risk Prediction for Early Stage Breast Cancer

Tests to better characterize tumor genomic architecture are quickly becoming a standard of care in oncology. For breast cancer, the use of gene expression assays for early stage disease is already common practice. These tests have found a place in risk stratifying the heterogeneous group of stage I-II breast cancers for recurrence, for predicting chemotherapy response, and for predicting breast cancer-related mortality. In the last 5 years, more assays have become available to the practicing oncologist. Given the rapidity with which this field has evolved, it is prudent to review the tests, their indications, and the studies from which they have been validated. We present a comprehensive review of the available gene expression assays for early stage breast cancer. We review data for several individual tests and comparative studies looking at risk prediction and cost-effectiveness.
SAO: A Stream Index for Answering Linear Optimization Queries

Linear optimization queries retrieve the top-K tuples in a sliding window of a data stream that maximize/minimize the linearly weighted sums of certain attribute values. To efficiently answer such queries against a large relation, an onion index was previously proposed to properly organize all the tuples in the relation. However, such an onion index does not work in a streaming environment due to fast tuple arrival rate and limited memory. In this paper, we propose a SAO index to approximately answer arbitrary linear optimization queries against a data stream. It uses a small amount of memory to efficiently keep track of the most "important" tuples in a sliding window of a data stream. The index maintenance cost is small because the great majority of the incoming tuples do not cause any changes to the index and are quickly discarded. At any time, for any linear optimization query, we can retrieve from the SAO index the approximate top-K tuples in the sliding window almost instantly. The larger the amount of available memory, the better the quality of the answers is. More importantly, for a given amount of memory, the quality of the answers can be further improved by dynamically allocating a larger portion of the memory to the outer layers of the SAO index. We evaluate the effectiveness of this SAO index through a prototype implementation.
Amino acid signatures in the normal cat retina

PURPOSE. TO establish a nomogram of amino acid signatures in normal neurons, glia, and retinal pigment epithelium (RPE) of the cat retina, guided by the premise that micromolecular signatures reflect cellular identity and metabolic integrity. The long-range objective was to provide techniques to detect subtle aberrations in cellular metabolism engendered by model interventions such as focal retinal detachment. METHODS. High-performance immunochemical mapping, image registration, and quantitative pattern recognition were combined to analyze the amino acid contents of virtually all cell types in serial 200-nm sections of normal cat retina. RESULTS. The cellular cohorts of the cat retina formed 14 separable biochemical theme classes. The photoreceptor —> bipolar cell —> ganglion cell pathway was composed of six classes, each possessing a characteristic glutamate signature. Amacrine cells could be grouped into two glycineand three y-aminobutyric acid (GABA)- dominated populations. Horizontal cells possessed a distinctive GABA-rich signature completely separate from that of amacrine cells. A stable taurineglutamine signature denned Miiller cells, and a broad-spectrum aspartate-glutamate-taurineglutamine signature was present in the normal RPE. CONCLUSIONS. In this study, basic micromolecular signatures were established for cat retina, and multiple metabolic subtypes were identified for each neurochemical class. It was shown that virtually all neuronal space can be accounted for by cells bearing characteristic glutamate, GABA, or glycine signatures. The resultant signature matrix constitutes a nomogram for assessing cellular responses to experimental challenges in disease models. (Invest Ophthalmol Vis Sci. 1998;39: 1685-1693)
The second transmembrane domain of the large conductance, voltage‐ and calcium‐gated potassium channel β1 subunit is a lithocholate sensor

Abstract Bile acids and other steroids modify large conductance, calcium- and voltage-gated potassium (BK) channel activity contributing to non-genomic modulation of myogenic tone. Accessory BK β1 subunits are necessary for lithocholate (LC) to activate BK channels and vasodilate. The protein regions that sense steroid action, however, remain unknown. Using recombinant channels in 1-palmitoyl-2-oleoyl-phosphatidylethanolamine/1-palmitoyl-2-oleoyl-phosphatidylserine bilayers we now demonstrate that complex proteolipid domains and cytoarchitecture are unnecessary for β1 to mediate LC action; β1 and a simple phospholipid microenvironment suffice. Since β1 senses LC but β4 does not, we made chimeras swapping regions between these subunits and, following channel heterologous expression, demonstrate that β1 TM2 is a bile acid-recognizing sensor.
An equilibrium pricing model for weather derivatives in a multi-commodity setting

Many industries are exposed to weather risk. Weather derivatives can play a key role in hedging and diversifying such risk because the uncertainty in a company’s profit function can be correlated to weather condition which affects diverse industry sectors differently. Unfortunately the weather derivatives market is a classical example of an incomplete market that is not amenable to standard methodologies used for derivative pricing in complete markets. In this paper, we develop an equilibrium pricing model for weather derivatives in a multi-commodity setting. The model is constructed in the context of a stylized economy where agents optimize their hedging portfolios which include weather derivatives that are issued in a fixed quantity by a financial underwriter. The supply and demand resulting from hedging activities and the supply by the underwriter are combined in an equilibrium pricing model under the assumption that all agents maximize some risk averse utility function. We analyze the gains due to the inclusion of weather derivatives in hedging portfolios and examine the components of that gain attributable to hedging and to risk sharing.
The Effects of Two-Year College on the Labor Market and Schooling Experiences of Young Men

This paper uses the NLSY to examine 1) the returns to two-year college, 2) whether attendance at a two-year college helps students to transfer to four-year college, and 3) whether reducing tuition would alter attendance by enough to affect labor outcomes. I find that the returns to a year of two-year college are large (7 to 10 percent). Completing an associate's degree raises wages further. One year of two-year credits has the same effect on subsequent four-year attendance as one year of four-year credits. Finally, simulations show that reducing tuition could raise income modestly by increasing college attendance.
Hierarchical Organization via a Facilitation Cascade in Intertidal Cordgrass Bed Communities

Abstract: It has recently been proposed that many communities are structured by a hierarchy of interactions in which facilitation by foundation species is of primary importance. We conducted the first explicit experimental test of this hypothesis by investigating the organization of positive interactions on New England cobblestone beaches. In this midintertidal community, wave‐generated substrate instability and solar stress largely limit marine organisms to the shelter of cordgrass beds. Cordgrass, which can establish and persist without the aid of other foundation species, facilitates a dense assemblage of inhabitants (e.g., mussels, snails, seaweeds) with roots/rhizomes that stabilize substrate and a dense canopy that baffles waves and provides shade. Within the cordgrass bed community, ribbed mussels further enhance physical conditions and densities of other species (e.g., amphipods, barnacles) by providing crevice space and hard substrate. We conclude that cordgrass bed communities are hierarchically...
Personnel Qualifications in Special Education: Legal and Practice Considerations

Chronic shortages of qualified personnel have been a persistent challenge in special education. Recent amendments to IDEA that emphasize participation and progress in the general education curricul...
Fracture parameter estimation from well-log data

We evaluated a method of deriving seismic fracture parameters from vertical-well-log data with the assumption that the fractured medium is transversely isotropic with a horizontal axis of symmetry (HTI). One approximation we used is that the observed vertical P-wave velocity is the same as the background isotropic P-wave velocity of the HTI medium. Another assumption was that the fractures and cracks are noninteractive and penny shaped. Using these approximations, we generated the fracture compliance matrix for each layer. Fracture parameters were then derived by constructing the HTI stiffness matrix for those layers. We tested our method using vertical-well-log data from a tight sand reservoir in Colorado, USA. “Thomsen-style” parameters were derived, and gas-filled fractures were identified on this log. The identified gas-filled fractures were compared to the production log data. The fracture density was also obtained at the well location within the depth of interest. We also found some problems and limitations caused by approximating vertical P-wave velocity the same as the background isotropic P-wave velocity.
Slow photoelectron velocity-map imaging spectroscopy of the phenoxide and thiophenoxide anions

High resolution anion photodetachment spectra of the phenoxide and thiophenoxide anions were obtained with slow electron velocity-map imaging. The spectra show transitions to the 2B1 neutral states of both species and to the A2B2 state of the thiophenoxy radical. Comparison of the spectra with Franck-Condon simulations allows several gas-phase vibrations to be assigned. The adiabatic electron affinities are determined to be 2.2538(8) eV and 2.3542(6) eV for phenoxy and thiophenoxy, respectively. The term energy of the A2B2 state of thiophenoxy is found to be 0.3719(9) eV, higher than the values reported in photodissociation experiments of thiophenol.
Automatic generation of modular mappings

Modular mappings have been recently proposed for optimization of algorithms that cannot be efficiently mapped by affine mappings. This paper addresses the problem of generating modular mappings that satisfy conditions for validity and optimality. In general, this is a difficult problem due to the presence of non-linear constraints. Hence, a method of O(n/sup 2/) complexity is provided to assign values to some entries of a transformation matrix so that non-linear constraints are transformed into linear ones, where n is the dimension of a computation domain. The proposed heuristic attempts to reduce the number of value-assigned entries and exclude as few solutions as possible. This paper also considers the issue of deriving the inverse transformation of a given modular mapping. It identifies a class of modular functions whose inverses result directly from computing the inverse of the (coefficient) matrix used to specify a modular mapping. An efficient method of O(n/sup 2/) complexity is provided to formulate the problem of generating such modular mappings as an integer linear programming problem.
STUDIES ON THE ANTIBACTERIAL ACTION OF THE SULFONAMIDE DRUGS : II. THE POSSIBLE RELATION OF DRUG ACTIVITY TO SUBSTANCES OTHER THANp-AMINOBENZOIC ACID.

1. In cultures of Staphylococus aureus in a synthetic medium nicotinamide and cozymase were shown to block the bacteriostatic action of chemically unrelated sulfonamide drugs as well as the chemically related compound sulfapyridine. The antibacterial properties of organic dyes totally unrelated to the sulfonamide compounds (methylene blue and thionine) were also nullified by the addition of cozymase to the culture medium. 2. The antagonistic action of the pyridine-containing coenzyme, cozymase, was found, by quantitative study, to be no greater against sulfapyridine than against other structurally dissimilar sulfonamide compounds. 3. The antidrug effects of nicotinamide and cozymase in staphylococcus cultures were observed to be directly proportional to their ability to stimulate the growth of the organism in the synthetic medium. When tested in cultures of B. coli in which they failed to accelerate bacterial growth, these same substances failed to influence the bacteriostatic action of the sulfonamide drugs. 4. The in vitro action of the coenzyme, cocarboxylase, as measured in the Warburg respirometer, was shown to be unaffected by the chemically related drug, sulfathiazole, even when the latter was present in great excess. The above observations fail to support the theory that sulfapyridine, sulfathiazole, and sulfadiazine prevent bacterial growth by interfering with the functioning of the chemically related coenzymes, cozymase, and cocarboxylase. The mode of action of sulfanilamide and its more common derivatives is discussed in the light of these observations, and a tentative theory is offered to explain the differences in bacteriostatic potency exhibited by the various sulfonamide compounds.
Discovery of single nucleotide polymorphisms in candidate genes associated with fertility and production traits in Holstein cattle

Identification of single nucleotide polymorphisms (SNPs) for specific genes involved in reproduction might improve reliability of genomic estimates for these low-heritability traits. Semen from 550 Holstein bulls of high (≥ 1.7; n = 288) or low (≤ −2; n = 262) daughter pregnancy rate (DPR) was genotyped for 434 candidate SNPs using the Sequenom MassARRAY® system. Three types of SNPs were evaluated: SNPs previously reported to be associated with reproductive traits or physically close to genetic markers for reproduction, SNPs in genes that are well known to be involved in reproductive processes, and SNPs in genes that are differentially expressed between physiological conditions in a variety of tissues associated in reproductive function. Eleven reproduction and production traits were analyzed. A total of 40 SNPs were associated (P < 0.05) with DPR. Among these were genes involved in the endocrine system, cell signaling, immune function and inhibition of apoptosis. A total of 10 genes were regulated by estradiol. In addition, 22 SNPs were associated with heifer conception rate, 33 with cow conception rate, 36 with productive life, 34 with net merit, 23 with milk yield, 19 with fat yield, 13 with fat percent, 19 with protein yield, 22 with protein percent, and 13 with somatic cell score. The allele substitution effect for SNPs associated with heifer conception rate, cow conception rate, productive life and net merit were in the same direction as for DPR. Allele substitution effects for several SNPs associated with production traits were in the opposite direction as DPR. Nonetheless, there were 29 SNPs associated with DPR that were not negatively associated with production traits. SNPs in a total of 40 genes associated with DPR were identified as well as SNPs for other traits. It might be feasible to include these SNPs into genomic tests of reproduction and other traits. The genes associated with DPR are likely to be important for understanding the physiology of reproduction. Given the large number of SNPs associated with DPR that were not negatively associated with production traits, it should be possible to select for DPR without compromising production.
The Influence of Antibiotics on Delayed Returns in Artificial Breeding

Summary A study of 112,312 first-service cows bred artificially during an 8-mo. period immediately prior to the routine addition of 500 units each of penicillin and streptomycin per milliliter of citrate-sulfanilamide-yolk extender revealed that a = 0.01 b = p the 28- to 35-day, 60- to 90-day and 150- to 180-day per cent non-returns were 79.1, 64.1 and 60.3, respectively. The corresponding values for 233,354 first-service cows bred during a 17-mo. period immediately following the change were 82.5, 73.0 and 69.7. The smaller percentage of delayed returns when antibiotics were used is interpreted as indirect evidence for a marked decrease in embryonic mortalities associated with control of infectious agents in semen. Bulls' fertility (28- to 35-day per cent non-returns) before as well as after the use of antibiotics was negatively correlated with the percentage of delayed returns, indicating that the semen per se also is a source of origin of some of these delayed returns. The among-bull variance for non-returns to first-service cows was reduced to less than 10 per cent of its original value by the addition of the antibiotics, penicillin and streptomycin, to the citrate-sulfanilamide-yolk extender. When antibiotics were used, the 150- to 180-day non-return percentages were predicted nearly as accurately from the 28- to 35-day non-returns as from the 60- to 90-day non-returns.
Earth Orbit v2.1: a 3-D visualization and analysis model of Earth's orbit, Milankovitch cycles and insolation

Abstract. Milankovitch theory postulates that periodic variability of Earth's orbital elements is a major climate forcing mechanism, causing, for example, the contemporary glacial–interglacial cycles. There are three Milankovitch orbital parameters: orbital eccentricity, precession and obliquity. The interaction of the amplitudes, periods and phases of these parameters controls the spatio-temporal patterns of incoming solar radiation (insolation) and the timing and duration of the seasons. This complexity makes Earth–Sun geometry and Milankovitch theory difficult to teach effectively. Here, we present "Earth Orbit v2.1": an astronomically precise and accurate model that offers 3-D visualizations of Earth's orbital geometry, Milankovitch parameters and the ensuing insolation forcing. The model is developed in MATLAB® as a user-friendly graphical user interface. Users are presented with a choice between the Berger (1978a) and Laskar et al. (2004) astronomical solutions for eccentricity, obliquity and precession. A "demo" mode is also available, which allows the Milankovitch parameters to be varied independently of each other, so that users can isolate the effects of each parameter on orbital geometry, the seasons, and insolation. A 3-D orbital configuration plot, as well as various surface and line plots of insolation and insolation anomalies on various time and space scales are produced. Insolation computations use the model's own orbital geometry with no additional a priori input other than the Milankovitch parameter solutions. Insolation output and the underlying solar declination computation are successfully validated against the results of Laskar et al. (2004) and Meeus (1998), respectively. The model outputs some ancillary parameters as well, e.g., Earth's radius-vector length, solar declination and day length for the chosen date and latitude. Time-series plots of the Milankovitch parameters and several relevant paleoclimatological data sets can be produced. Both research and pedagogical applications are envisioned for the model.
A Model-Based Fault-Detection and Prediction Scheme for Nonlinear Multivariable Discrete-Time Systems With Asymptotic Stability Guarantees

In this paper, a novel, unified model-based fault-detection and prediction (FDP) scheme is developed for nonlinear multiple-input-multiple-output (MIMO) discrete-time systems. The proposed scheme addresses both state and output faults by considering separate time profiles. The faults, which could be incipient or abrupt, are modeled using input and output signals of the system. The fault-detection (FD) scheme comprises online approximator in discrete time (OLAD) with a robust adaptive term. An output residual is generated by comparing the FD estimator output with that of the measured system output. A fault is detected when this output residual exceeds a predefined threshold. Upon detecting the fault, the robust adaptive terms and the OLADs are initiated wherein the OLAD approximates the unknown fault dynamics online while the robust adaptive terms help in ensuring asymptotic stability of the FD design. Using the OLAD outputs, a fault diagnosis scheme is introduced. A stable parameter update law is developed not only to tune the OLAD parameters but also to estimate the time to failure (TTF), which is considered as a first step for prognostics. The asymptotic stability of the FDP scheme enhances the detection and TTF accuracy. The effectiveness of the proposed approach is demonstrated using a fourth-order MIMO satellite system.
Investigation of challenges towards achieving sub-millimeter accuracy for UWB localization

We are studying the reasons preventing us from achieving sub-millimeter accuracy for UWB indoor localization which suffers from intense multipath interference. Using just the I-Channel offers better accuracy because of the I-Q alignment problem, but it requires great number of samples averaging, and causes unstable system operation. Non-coherent detection is an interesting alternative, since it eliminates the I-Q-channel problem. Also, our project operates indoor where attenuation is not a big problem, and the gain inherited in I-Channel detection is no more attractive to us. Moreover, a stable system is required to allow for pining out other sources of error that get lost due to averaging.