cssi/SciSciGPT-SciSciNet huggingface dataset:
Combined effect of asphalt concrete cross-anisotropy and temperature variation on pavement stress–strain under dynamic loading

Abstract This study investigates the combined effects of asphalt concrete (AC) cross-anisotropy and temperature on asphalt pavement’s stress–strain under moving wheel loads. To facilitate this study, a dynamic Finite Element Model (FEM) of an instrumented pavement section on Interstate-40 (I-40) near Albuquerque, New Mexico, is developed in ABAQUS incorporating depth-temperature variations in the AC layer under a truck wheel loading. Cross-anisotropy in the model is defined as the ratio of horizontal to vertical modulus ( n -value) of the AC. Field compacted AC cores were collected from the instrumented pavement section and tested in the laboratory to determine the n -value and viscoelastic parameters, which are incorporated in the FEM model using the User Defined Material (UMAT) interface in ABAQUS. Model is validated using field measured deflections and strains values under Falling Weight Deflectometer (FWD) test. The validated model is used for a parametric study by varying n -values of AC material under different pavement temperatures. It is observed that the horizontal tensile strain at bottom of the AC layer decreases as the n -value approaches 1.0 (isotropy). It indicates that the horizontal tensile strain decreases as the horizontal modulus of the AC increases. It is also observed that the vertical strains on top of pavement layers decreases with an increase in n -value. It indicates that increase in horizontal modulus of the AC leads to decrease in the vertical strains of pavement layers. The parametric study based on pavement temperature variation shows that horizontal tensile strain at bottom of the AC layer as well as vertical strains on top of AC, base, subbase, and subgrade are highly sensitive to temperature variation in AC layer.
Employment of People with Disabilities in Bulgaria - Problems and Perspectives (Integrated vs. Specialised Employment)

In the practice and in literature there is a vast range of illness that can lead to disabilities, and also other reasons for someone to become disabled. This paper will try to outline the basic difficulties connected in labor realization of people with disabilities: the existing legal, social and economic issues in that sphere. In order to accomplish this I shall outline four major problems: - To give an overview of disability itself and the constraint it creates in employment; - Examination of major legal and social provisions for economic realization of people with disabilities in Bulgaria, in the transition towards market economy; - Evaluation of the desirability of policies and derivation of lessons that can be usefully applied in different situations. The paper uses the terminology of the International Classification of Impairments, Disabilities and Handicaps (ICIDH) of the World Health Organization (WHO), using "disabled" and "disability" as the general descriptive terms rather than "handicapped" and "handicap."
An Abd-B Class HOX·PBX Recognition Sequence Is Required for Expression from the Mouse Ren-1c Gene

Expression from the mouse Ren-1(c) gene in As4.1 cells is dependent on a proximal promoter element (PPE) located at approximately -60 and a 241-base pair enhancer region located at -2625 relative to the transcription start site. The PPE (TAATAAATCAA) is identical to a consensus HOX.PBX binding sequence. Further, PBX1b has been shown to be a component of a PPE-specific binding complex present in nuclear extracts from As4.1 cells. The binding affinities of different paralog HOX members to the PPE were examined in the absence or presence of PBX1b. HOXB6, -B7, and -C8 failed to bind the PPE alone but showed weak affinity in the presence of PBX1b. In contrast, HOXD10 and to a lesser degree HOXB9 bound the PPE with high affinities regardless of whether PBX1b was present. Abd-B HOX members, including HOXD10, -A10, -A9, -B9, and -C9, are expressed in As4.1 cells. The ability of HOX and PBX1b to form a ternary complex with PREP1 on the PPE is also demonstrated both in vivo and in vitro. Point mutations in either the HOX or PBX half-site of the PPE disrupted the formation of the HOX.PBX complex and dramatically decreased transcriptional activity of the Ren-1(c) gene demonstrating that both the HOX and PBX half-sites are critical for mouse renin gene expression. These results strongly implicate Abd-B class Hox genes and their cofactors as major determinants of the sites of renin expression.
Olivine enigma: Why alteration controls the seismic properties of oceanic gabbros

[1] The objective of this study was to determine whether the effects of low Mg content and/or cracks that typically populate olivine grains can explain why P and S wave velocities in samples of oceanic gabbro do not increase with increasing olivine content. The Mg content of olivine in these rocks is known to be appreciably less than Fo90, and optical, SEM, and electron microprobe analyses indicate that the “olivine” is actually an aggregate of olivine and 5–15% crack fill consisting of talc and/or serpentine plus magnetite. Voigt average models show that there is a strong, positive correlation between P wave velocities and Fo90 content but no correlation with Fo73. Because of its Mg content, olivine that is typical of oceanic gabbros does not influence seismic velocities. Adding 11% alteration of olivine to serpentine plus magnetite in the form of crack fill to the Fo73 model yields a nearly exact match between the model and measured P and S wave velocities. The fact that the crack fill consists largely of talc and/or serpentine indicates that these minerals formed by hydrothermal alteration in young, hot (>150°C) lower crust. Hence our results apply to gabbros in situ, as well as to the laboratory samples; seismic velocities in lower oceanic crust produced at high and intermediate spreading rates are controlled principally by the degree of hydrothermal alteration of the gabbros that compose the lower crust.
Chapter 4 Hydrogen in III-V Nitrides

This chapter discusses hydrogen in III–V nitrides. The incorporation of acceptor impurities during metal organic chemical vapor deposition (MOCVD) growth is not sufficient; either a postgrowth processing step involving low-energy electron beam irradiation (LEEBI) or thermal annealing is required. According to the behavior of hydrogen in other semiconductors, hydrogen is expected to be involved in other important processes as well. The impurity introduces a level in the bandgap and the charge state depends on the occupation of that level. The charge state determines the most favorable location of hydrogen in the semiconductor lattice. In the positive charge state (H + , essentially a proton), hydrogen seeks out regions of high-electronic-charge density.
Miniaturized Omnidirectional Horizontally Polarized Antenna

A novel miniaturized impedance matched antenna with omnidirectional horizontally polarized radiation pattern is presented. The antenna structure resembles a circular loop formed by a circular array of shunt miniaturized n-fold resonant dipole antennas, which will be referred to as miniature composite wire-loop antenna (MCWLA). The proposed antenna does not require an external matching network and can easily be matched to balanced ports with any desired impedance. MCWLAs can be made to be a very small fraction of the wavelength and yet to provide a relatively high radiation efficiency. The antenna input impedance can be adjusted by the number of array n-folded dipole elements, the number of folds and the diameter of the composite loop. The input impedance can be lowered by increasing the number of elements and/or by decreasing the loop diameter. Conversely, the input impedance, for a fixed number of elements and diameter, can be increased by increasing the fold number. The antenna efficiency increases with increasing the loop diameter. To demonstrate the proposed concept, a MCWLA is designed with diameter ${\lambda}/8$ and is designed and fabricated using the standard PCB approach on a thin substrate ( $\lambda /500$ ). To achieve omnidirectional radiation pattern in H-plane, a minimum of three elements fed in-phase around the inscribing loop are used. It is shown that impedance match to a $50\hbox{-}\Omega$ line can be achieved using fourfold miniaturized dipole elements. The simulation shows strong uniform current distribution on the A transformer balun that is used to connect the balanced port of the antenna to a small coaxial line at the center of the loop. The measured gain, including the loss through the balun, is to be 0 dBi and the gain variation in the H-plane is shown to be less than 0.5 dB for the prototype MCWLA.
Reappraising Medfly Longevity

In this article we explore the usefulness of a quantile regression formulation of reanalyzing a large experimental study that monitored age-specific mortality in a sample of roughly 1.2 million Mediterranean fruit flies. The quantile regression approach appears useful in refining several of the conclusions drawn from the original study including the apparent decline in mortality rates at advanced ages, and the gender crossover effect in survival functions for medflies.
Implicación laboral y emociones en el trabajo: Estudio empírico de sus factores determinantes.

La implicacion laboral de los empleados con su puesto de trabajo es una variable actitudinal que adquiere caracter estrategico en las organizaciones del siglo XXI. El objetivo de la presente investigacion es establecer un modelo de prediccion del nivel de implicacion emocional de los asalariados europeos con sus puestos de trabajo, en funcion de ciertas variables personales, laborales, actitudinales y de bienestar. Para lograr este fin se emplea, por un lado, un modelo econometrico tradicional, como la regresion logistica binaria y, por otro, una alternativa complementaria: la red neuronal artificial, entrenada a traves de dos algoritmos matematicos: Multilayer Perceptron y Extreme Learning Machine. Los resultados obtenidos identifican los factores determinantes de la implicacion emocional, evidenciando una eficacia ligeramente superior de los sistemas neuronales artificiales. La investigacion concluye que, en la actual coyuntura de crisis global, cualquier practica de gestion orientada a facilitar la implicacion del individuo con su entorno laboral inmediato se configura como un elemento critico para la obtencion de resultados organizativos sostenibles a largo plazo y, en consecuencia, para la propia supervivencia empresarial.
Lung homing CTLs and their proliferation ability are important correlates of vaccine protection against influenza

We conducted a study to evaluate the protective efficacy in mice of vaccination with novel adenovirus vectors expressing an influenza A nucleoprotein (AdFluA-NP) based on isolates from non-human primates. In a previous study, we had observed that AdFluA-NP vectors can induce similar T cell responses in mice yet differ in ability to protect animals from lethal challenge with influenza A virus. To better define correlates of protection, we extended our study design to include additional novel AdFluA-NP vectors, and to evaluate cytotoxic T lymphocyte (CTL) responses in the spleens and lungs of immunized mice prior to virus challenge. As in our previous study, all vectors induced similar numbers of antigen-specific interferon gamma (IFNγ) secreting T cells and memory T cells in the spleen 4 weeks post immunization, but differed in their ability to protect the animals from lethal infection. However, cytokine-secreting NP antigen-specific CTLs in the lungs of mice from immunization groups that survived lethal challenge showed greater proliferative ability and higher CD27 expression. In addition, NP antigen-specific peripheral blood lymphocytes from protected mice showed greater proliferative ability after ex vivo stimulation. Our results provide additional correlates of protection that should be considered when developing anti-influenza vaccines.
Hypothermia relieves oxidative stress in reperfused skeletal muscle following partial ischemia.

The impact of hypothermia on reperfusion-associated oxidative stress in postischemic skeletal muscle was evaluated in a small animal model of high-grade partial ischemia. The infrarenal aorta of heparinized Sprague-Dawley rats was clamped for 90 min, declamped, and then reperfused for 60 min. Previous characterization of this model with 51Cr-tagged microspheres revealed that hindlimb perfusion during aortic clamping continued at 16.6% of baseline values. Resting transmembrane potential difference (Em) and tissue malondialdehyde (MDA), lactate and high-energy phosphate content were determined in hindlimb skeletal muscle at baseline, during ischemia, and upon reperfusion. Four experimental groups (N = 7 in each group) were studied: control animals underwent aortic clamping and declamping; hypothermia animals underwent topical cooling of hindlimbs prior to aortic clamping, with muscle temperatures maintained between 5 and 15°C during ischemia; sham animals underwent midline laparotomy only; and hypothermia-sham animals underwent cooling and midline laparotomy only. During ischemia, resting Em(−mV) was significantly depolarized (P < 0.05 versus baseline) in control (74.9 ± 0.8 from 91.0 ± 0.1), hypothermia (64.4 ± 1.1 from 90.9 ± 0.3), and hypothermia-sham (67.2 ± 1.4 from 90.9 ± 0.4) animals. Upon reperfusion, resting Em remained depolarized in control animals (74.7 ± 1.6), while repolarization occurred in hypothermia (74.7 ± 1.6), while repolarization occurred in hypothermia (88.8 ± 1.1) and hypothermia-sham (90.7 ± 0.3) animals. Tissue MDA content (nmol/g wet tissue), a marker of phospholipid peroxidation, was markedly elevated (P < 0.05 versus baseline) during ischemia in control (121.5 ± 18.4 from 67.1 ± 7.2) and hypothermia (118.5 ± 18.7 from 66.8 ± 7.5) animals, and continued to increase upon reperfusion in control animals (190.5 ± 14.0; P < 0.05 versus ischemia), while returning to baseline values in hypothermia animals (77.0 ± 12.8; P = NS versus baseline). These data indicate that high-grade partial ischemia in skeletal muscle is accompanied by significant phospholipid peroxidation, and that antecedent regional hypothermia markedly attenuates subsequent and further reperfusion-associated oxidative injury.
Percutaneous Testis Biopsy: An Alternative to Open Testicular Biopsy in the Evaluation of the Subfertile Man

AbstractPurpose: We evaluated the safety and efficacy of percutaneous testis biopsy by comparing the ultrasound appearance and histological status of testicular parenchyma obtained to those noted after open testis biopsy.Materials and Methods: A total of 51 consecutive infertile men with azoospermia or severely impaired semen quality, in whom ductal obstruction was suspected, underwent percutaneous (31) or open (20) testis biopsy, with 58 and 34 procedures performed, respectively. Scrotal ultrasound was performed preoperatively, and at 2 weeks and 1, 3 and 6 months after biopsy. In addition, immunoglobulins G and A antisperm antibody assays were obtained preoperatively and postoperatively. Two biopsy specimens were obtained from each testis for formal histological evaluation. A touch preparation was also performed and examined immediately for mature spermatozoa using phase contrast microscopy.Results: All biopsies yielded adequate tissue for diagnosis and morphometric analysis. Of 58 percutaneous biopsies...
Domain coarsening in systems far from equilibrium.

The growth of domains of stripes evolving from random initial conditions is studied in numerical simulations of models of systems far from equilibrium such as Rayleigh-Benard convection. The size of the domains deduced from the inverse width of the Fourier spectrum is found to scale as t^1/5 for both potential and nonpotential models. The morphology of the domains and the defect structures are, however, quite different in the two cases, and evidence is presented for a second length scale in the nonpotential case growing as t^1/2.
Feedback-based access and power control for distributed multiuser cognitive networks

Cognitive radio networks enable secondary users to utilize spare bandwidth of primary users by limiting their interference. Moving beyond the traditional listen-before-talk paradigm, we propose a cognitive access methodology that exploits the feedback channel in two-way primary communication links for better spectrum utility and protection of primary users against secondary interference. We let secondary users dynamically control access and power based on primary ACK/NACK messages. We develop an optimal access policy applicable to multiple secondary user pairs. We also devise a distributed power control policy for multiple secondary users to maximize their individual throughput without significant cumulative interference to the primary link. Our distributed access and power control schemes can effectively provide good SU performance and primary protection without requiring central coordination.
Age-related modifications of potassium homeostasis and synaptic transmission during and after anoxia in rat hippocampal slices.

Abstract Age-related changes in the capacity of the brain to survive short anoxic episodes were studied in stratum pyramidale (region CA1) of hippocampal slices from control (6–7 months) and aged (26–27 months) rats. Our primary interest was in how aging affected the ability of slices to maintain or to recover extracellular potassium ion (K + o ) homeostasis and orthodromically-stimulated field potentials during and after anoxia. During anoxia, K + o homeostasis was lost faster in slices from aged rats. Following anoxia, K + o homeostasis recovered more slowly, and synaptic transmission recovered less completely, in aged slices. These studies provide what is believed to be the first demonstration that aging diminishes the capacity of brain tissue to maintain K + o during hnoxia and to recover K + o homeostasis and homeostasis and synaptic transmission following anoxia, and support suggestions that the aged brain is more vulnerable to anoxia.
A REVIEW OF TREATMENT PLANNING AND DOSE CALCULATION IN VETERINARY RADIATION ONCOLOGY

Because radiation cell killing follows Poisson statistics, radiation dose response curves for tumors and normal tissue response are sigmoidal in shape. This shape implies that small errors in delivery of radiation dose can result in large changes in the probability of normal tissue necrosis or tumor control. Thus it is important for veterinarians involved with radiation oncology to be familiar with the basic aspects of radiation physics and dose calculation as they relate to radiation therapy. In this paper, we present a review of pertinent physics and treatment planning relative to orthovoltage and cobalt irradiation. The usefulness of radiation treatment planning computers is emphasized for improving the radiation oncologist's knowledge of dose distribution and selection of the optimum treatment plan.
Representing heritage and loss on the Brittany coast: sites, things and absence.

This is an essay about the interplay of objects, art and visual culture in several community museums and historical sites dedicated to local social history in coastal Brittany. There, in the late nineteenth and early twentieth centuries, Breton maritime culture invented a range of compensatory ritual objects, sites and practices to account for loss of life at sea. The presentation of this material culture of mourning in small museums, regional museums and ecomuseums on the Breton North Coast and the islands of Sein and Ouessant are examined in this essay. These material objects once bore material witness to crucial moments in the life of the family and today serve to represent the community’s collective memories and to narrate the community’s heritage to the outside world. In several cases examined in this essay, literary representations, art and visual culture are compared to heritage sites and museums. Methodologies are drawn from social art history, studies of tourism and collecting, museum studies, ma...
Imperfect price discrimination in a vertical differentiation model

Abstract We explore the competitive implications of third-degree price discrimination based on consumer information of varying degrees of “precision” in a vertical differentiation duopoly model. We show that, if the cost of information is below a threshold, only the high quality firm will acquire it and offer targeted promotions, while the low quality firm will commit to a uniform price, for any degree of consumer information precision. Equilibrium profits of the high quality firm are monotonically increasing and that of the low quality firm monotonically decreasing as a function of the consumer information precision. Finally, social and consumer welfare are monotonically increasing with respect to the precision of consumer information.
Isomerization and hydrogenolysis of trimethylbenzenes with platinum on acidic and nonacidic supports

Abstract For commercial high-pressure naphtha reforming conditions, platinum has a similar demethylation activity when supported on acidic or nonacidic alumina. Platinum on nonacidic alumina exhibits a low trimethylbenzene isomerization activity under conditions where platinum on an acidic support produces an equilibrium mixture. The xylene isomers produced by demethylation are consistent with a demethylation mechanism without isomerization. The relative rates of demethylation and isomerization of 1,3,5-trimethylbenzene should be a method of measuring the hydrogenation and acidic functions of bifunctional catalysts. The results also demonstrate that the aromatics formed by alkane dehydrocyclization under reforming conditions do not extensively isomerize when a nonacidic support is used.
Risk communication with generalized uncertainty and linguistics

Civil Engineers have the opportunity and obligation to lead society to more effective decision-making for built environment risk trade-offs. This paper addresses the gap between classical mathematical analysis and the linguistic-based issues and factors that play a major role on societal decisions. A large stumbling block is the utilization of the fairly extensive literature in social psychology related to risk avoidance, in formal mathematical decision frameworks based on probabilistic analysis. Fundamental principles of generalized information theory may be helpful in casting sociological considerations of perceived risk into linguistic frameworks so that the mathematics of information theory can be applied to develop decision guidelines. Fuzzy set theory is one example where probability-based uncertainty has been broadened to incorporate linguistic input. Other examples are monotone measures, such as Mobius representations, imprecise probabilities and decision weights, as well as Shannon entropy.
Changes in Self-Efficacy, Challenge Avoidance, and Intrinsic Value in Response to Grades: The Role of Achievement Goals

The relationship between achievement goals and changes in students' self-efficacy, challenge avoidance, and intrinsic value in response to grades was examined in a short-term longitudinal study of 361 college students. Data were collected at the beginning of the semester and immediately after students received their grades on their first major exam or paper. A mastery goal was associated with enhanced motivation and a performance-avoidance goal was associated with diminished motivation around the receipt of grades. A performance-approach goal was associated with diminished motivation when students received low grades but not high grades. The same pattern of relationships between goals and changes in motivation was found when students' perceptions of success were analyzed instead of grades. Theoretical and practical implications are discussed.
Structure of DNA near long tandem arrays of alpha satellite DNA at the centromere of human chromosome 7

The centromeric regions of human chromosomes contain long tracts of tandemly repeated DNA, of which the most extensively characterized is alpha satellite. In a screen for additional centromeric DNA sequences, four phage clones were obtained which contain alpha satellite as well as other sequences not usually found associated with tandemly repeated alpha satellite DNA, including L1 repetitive elements, an Alu element, and a novel AT-rich repeated sequence. The alpha satellite DNA contained within these clones does not demonstrate the higher-order repeat structure typical of tandemly repeated alpha satellite. Two of the clones contain inversions; instead of the usual head-to-tail arrangement of alpha satellite monomers, the direction of the monomers changes partway through each clone. The presence of both inversions was confirmed in human genomic DNA by polymerase chain reaction amplification of the inverted regions. One phage clone contains a junction between alpha satellite DNA and a novel low-copy repeated sequence. The junction between the two types of DNA is abrupt and the junction sequence is characterized by the presence of runs of A's and T's, yielding an overall base composition of 65% AT with local areas > 80% AT. The AT-rich sequence is found in multiple copies on chromosome 7 and homologous sequences are found in (peri)centromeric locations on other human chromosomes, including chromosomes 1, 2, and 16. As such, the AT-rich sequence adjacent to alpha satellite DNA provides a tool for the further study of the DNA from this region of the chromosome. The phage clones examined are located within the same 3.3-Mb SstII restriction fragment on chromosome 7 as the two previously described alpha satellite arrays, D7Z1 and D7Z2. These new clones demonstrate that centromeric repetitive DNA, at least on chromosome 7, may be more heterogeneous in composition and organization than had previously been thought.
An Experimental Study of Multidimensional Hierarchical Accounting Data: Drill‐Down Paths Can Influence Economic Decisions

Although decision support systems utilizing multidimensional hierarchical data have rightfully been praised for their ability to enhance decision making, we find that the drill‐down path offered by such systems can influence economic decisions—sometimes in a suboptimal fashion. Our experimental investigation offers profitmaximizing monetary incentives to decision makers who navigate a simple multidimensional system. Specifically, decision makers view three possible drill‐down paths that each contain three lower‐level outcomes of subunit performance (i.e., only nine possible outcomes exist). We manipulate the predictive ability of aggregate data by changing the system‐offered drill‐down path. In our experiment, we keep all numeric performance outcomes constant; however, half of the time, the optimal outcome lies within the best aggregate level performer and half the time it does not. We find economic decisions are significantly worse when aggregate level performance fails to predict the optimal lower‐level...
Indiana soybean system model (ISSM): II. Mexican bean beetle model development, integration and evaluation

Abstract An age-structured, distributed delay model was used to simulate the population dynamics of Mexican bean beetle (MBB), Epilachna varivestis Mulsant, a sporadic insect pest of soybeans. The MBB model was integrated with a soybean crop model as part of the Indiana soybean system model (ISSM). Results indicated that the model was able to capture the essential aspects of pest dynamics. Life table statistics based on simulation results were close to observed values for laboratory conditions (simulated intrinsic rate of increase, r = 0.056 and observed r = 0.053) and under field conditions (simulated r = 0.011 and observed r = 0.015). Simulated MBB population patterns and peak values were in good agreement with observed data. Differences between simulated and observed population patterns of immature MBB stages were greater than that of adults. Incorporation of mortality due to individual rainstorms and other weather events, and effect of alternate hosts and movement (secondary influx, emigration, etc.) seem to be important for simulating soybean production in a specific field. The model was used to evaluate the effects of crop variety, planting dates, weather and insect influx patterns on soybean yield. Results from simulation experiments showed that ‘Williams 82’ variety was more susceptible to yield loss (up to 45%) from MBB infestations, than the earlier maturing ‘Century 84’ (up to 25% yield loss). This susceptibility is due to the coincidence of the vulnerable crop stage (pod-setting and seed-filling stages) with the occurrence of the peak populations of MBB stages which cause most of the damage. Late planting tends to mitigate this susceptibility. As the influx patterns determine the extent of yield loss, the timing and magnitude of insect influx should be detected and estimated using timely scouting of fields.
Fertility, segregation at a herbicide‐resistance locus, and genome structure in BC1 hybrids from two important weedy Amaranthus species

Field studies have established high potential for hybridization between two important and often coexisting weedy species, Amaranthus hybridus and Amaranthus tuberculatus . Prezygotic reproductive barriers between these species are believed to be limited to pollen competition and availability. A greenhouse study showed that a herbicide-resistance gene ( ALS ) from A. hybridus could be introgressed into an advanced A. tuberculatus background (BC 2 ). However, evidence is lacking in support of such transfer in nature. Postzygotic reproductive barriers may minimize, if not preclude, natural introgression. Indeed, A. hybridus × A. tuberculatus hybrids are characterized by reduced fertility and even floral neuterism. The purpose of this study was to assess hybrid fertility in the BC 1 generation and its relationship with genome structure and segregation at ALS. Fertility was assessed by measuring seed output and by pollen evaluation, and segregation at ALS was determined via a molecular marker system. The two parental species have the same ploidy (2n = 32) but differ in DNA content (2C) values, with A. tuberculatus chromosomes being on average 29% greater than those of A. hybridus . Given that most (98%) BC 1 s were homoploid, 2C values were used as indicators of relative genomic constitution. Fertility in the BC 1 generation was greater than that of F 1 s, and 3% of BC 1 s had seed output similar to that of the parental species. Fertility in the BC 1 did not correlate (in a strict way) with reconstitution of parental genomes. Hybrid sterility appeared to be controlled by relatively few loci. Heterozygosity at ALS was negatively correlated with fertility. Also, the A. tuberculatus ALS allele was not observed in the A. hybridus sexual condition, monoecism. Linkage of ALS to a locus associated (directly or via epistasis) with hybrid sterility may explain the fertility penalty observed with ALS introgression. Moreover, this linkage might explain why sequenced herbicide-resistance ALS alleles from sympatric A. tuberculatus and A. hybridus populations show independent evolution.
PSYCHOLOGICAL DIFFERENTIATION AS A FACTOR IN CONFLICT RESOLUTION1

Previous studies have shown that persons matched in level of differentiation are likely to develop greater interpersonal attraction in the course of an interaction than mismatched persons. These studies were all conducted in situations where the interacting persons were working toward a common goal. To test the hypothesis that situational variables may moderate match-mismatch effects, the present study investigated these effects when the interacting persons were in conflict. On the basis of their performance in tests of field-dependence-independence, Ss were selected as relatively high (Hi-Diff Ss) or relatively low (Lo-Diff Ss) in level of differentiation. Three kinds of dyads were composed–Hi-Diff/Hi-Diff, Lo-Diff/Lo-Diff, and Hi-Diff/Lo-Diff–and the task set for the dyad members was to reconcile conflict on an issue about which they were known to disagree. It was predicted that because of the more accommodating quality of Lo-Diff persons, dyads consisting of one or two such Ss would more often reconcile their disagreements and show greater interpersonal attraction than dyads consisting of two Hi-Diff Ss. Both predictions were confirmed, supporting the hypothesis that the outcome of match or mismatch is mediated by situational variables.
1α,25-Dihydroxyvitamin D3 Modulates CYP2R1 Gene Expression in Human Oral Squamous Cell Carcinoma Tumor Cells

Oral squamous cell carcinomas (OSCC) are the most common malignant neoplasms associated with mucosal surfaces of the oral cavity and oropharynx. 1α,25-Dihydroxyvitamin D3 (1,25(OH)2D3) is implicated as an anticancer agent. Cytochrome P450 2R1 (CYP2R1) is a microsomal vitamin D 25-hydroxylase which plays an important role in converting dietary vitamin D to active metabolite, 25-(OH)D3. We identified high levels of CYP2R1 expression using tissue microarray of human OSCC tumor specimens compared to normal adjacent tissue. Therefore, we hypothesize that 1,25(OH)2D3 regulates CYP2R1 gene expression in OSCC tumor cells. Interestingly, real-time RT-PCR analysis of total RNA isolated from OSCC cells (SCC1, SCC11B, and SCC14a) treated with 1,25(OH)2D3 showed a significant increase in CYP2R1 and vitamin D receptor (VDR) mRNA expression. Also, Western blot analysis demonstrated that 1,25(OH)2D3 treatment time-dependently increased CYP2R1 expression in these cells. 1,25(OH)2D3 stimulation of OSCC cells transiently transfected with the hCYP2R1 promoter (−2 kb)-luciferase reporter plasmid demonstrated a 4.3-fold increase in promoter activity. In addition, 1,25(OH)2D3 significantly increased c-Fos, p-c-Jun expression, and c-Jun N-terminal kinase (JNK) activity in these cells. The JNK inhibitor suppresses 1,25(OH)2D3, inducing CYP2R1 mRNA expression and gene promoter activity in OSCC cells. Furthermore, JNK inhibitor significantly decreased 1,25(OH)2D3 inhibition of OSCC tumor cell proliferation. Taken together, our results suggest that AP-1 is a downstream effector of 1,25(OH)2D3 signaling to modulate CYP2R1 gene expression in OSCC tumor cells, and vitamin D analogs could be potential therapeutic agents to control OSCC tumor progression.
Natural substrates of the ubiquitin proteolytic pathway.

Martin Rechsteiner Department of Biochemistry University of Utah School of Medicine Salt Lake City, Utah 84112 To many, control of gene expression will conjure up the synthesis of new DNA-binding proteins. Yet, almost two decades ago, Schimke (1973) pointed out that rapid prote- olysis would be central to certain regulatory mechanisms. He deduced that the time required to alter levels of a regu- latory protein is tightly coupled to the protein’s half-life. Rapid changes in concentration necessitate short-lived proteins, and a growing list of rapidly degraded transcrip- tion factors and oncoproteins confirms Schimke’s analy- sis. However, it is not transcription per se, but rather a striking connection between proteolysis and control of the cell cycle that has sparked the recent interest in protein degradation. Mutations that inactivate components of the ubiquitin (Ub) proteolytic pathway (see below), such as cdc34 in budding yeast (Goebl et al., 1988) and ts85 in mouse (Finley et al., 1984) arrest cells at specific stages in the mitotic cycle. These observations, coupled with the demonstration that a single protein, cyclin B, must be de- graded for cells to exit mitosis (Murray et al., 1989) ac- count for the growing interest in protein degradation. Despite increased research in the area of intracellular proteolysis, a number of key questions remain unan- swered. For example, how many pathways do cells pos- sess for destroying their constituent proteins-5,50,500? Is an individual protein a substrate for several degradative pathways, or is its level typically controlled by a single pathway? In general, are proteins modified before being degraded? What features of a protein determine its aver- age lifetime within a cell? Although answering these questions will take us well into the future, recent studies on Ub-mediated proteolysis promise that some answers will be forthcoming. Ub is a highly conserved, 78 residue protein found only in eukary- otes. The macromolecule is unique in its ability to become reversibly cross-linked to other cellular proteins. Forma- tion of isopeptide bonds between the carboxyl terminus of Ub and lysine amino groups on acceptor proteins is associated with various biological processes ranging from insect flight-muscle organization to chromatin structure and lymphocyte homing (reviewed by Rechsteiner, 1988). In these situations Ub may function as a movable binding site promoting the association of proteins that do not have complementary surfaces. Ub is most fully characterized, however, as an essential component of a major cellular proteolytic pathway(s). Its widely accepted role as a proteolytic cofactor was discov- ered by Hershko and his colleagues (reviewed in Hershko, 1988) who elucidated most of the biochemical reactions presented in the figure. Ub is activated by El, an enzyme that hydrolyzes ATP to form a reactive thiol ester with the carboxyl terminus of Ub. A family of carrier proteins, the
Effect of Leukocyte Interferon on Urinary Excretion of Cytomegalovirus by Infants

Five infants with symptomatic cytomegalovirus infections and high urinary titers of cytomegalovirus were treated with interferon in doses of 1.7-3.5 X 10(5) reference units/kg per day for seven to 14 days. Six courses of treatment were given. One of two infants treated with the largest dose of interferon had transient suppression of viruria; no suppression was noted during the other five courses of treatment. Adverse effects noted included a low rate of weight gain, a transient elevation of serum aspartate aminotransferase and fever. Further trials are needed to determine whether larger doses of a more purified preparation of interferon will eliminate viruria in infants with sytomegalovirus infection, but careful assessment of toxicity will be necessary in this population of patients.
GVHD and relapse: to B or not to B

Comment on Miklos et al, page \__\_|\_ In a retrospective study of 121 hematopoietic stem cell transplantation patients, Miklos and colleagues apply a new ELISA assay for serum antibodies to H-Y antigens coded by the Y chromosome. They show that the presence of these antibodies is common in male
Regulation of the expression of ribosomal protein genes in Escherichia coli.

The in vivo expression of genes coding for ribosomal proteins has been examined by using a quantitative RNA-DNA hybridization assay. Total cellular RNA isolated from exponential-phase cultures of Escherichia coli growing at rates between 0·67 and 2·10 doublings per hour and from cultures following a nutritional shift-up was hybridized to DNA from a λ transducing phage carrying at least 22 ribosomal protein genes. These r-protein genes code for about 400,000 daltons of protein or about half of the total protein per ribosome. The results indicate that the fraction of the total cellular RNA which is homologous to the r-protein genetic region on the transducing phage, s , increases with increasing growth rate such that s = 0·0016 μ + 0·0006, where μ is the steady-state growth rate in doublings per hour. Comparison of the rate of synthesis of the r-proteins coded for by genes on the phage and the level of r-protein messenger RNA homologous to these genes during steady-state and transition conditions indicates that the expression of r-protein genes is controlled primarily by a mechanism which regulates the amount of mRNA for r-protein which is available for translation. This control may be exercised either at the level of initiation of transcription at the promotors for r-protein genes or at the level of the stability of the r-protein mRNA. The results further suggest the existence of a second control mechanism which influences the translation of r-protein mRNA.
The generation of MHC class II gene polymorphism in the genus Mus

Nucleotide sequences of exon 2 from 46 alleles of the murine MHC class II Aβ gene derived from 12 rodent species were determined using the polymerase chain reaction (PCR). This exon (273 bp) exhibited extensive nucleotide sequence diversity that did not follow predicted phylogenetic relationships. The nucleotide sequence diversity of exon 2 was focussed predominantly in five discrete sub-domains which contained polymorphic sequence motifs. These sub-domains each encode a segment of the antigen binding site of MHC class II molecule. The alleles in each sub-domain were organized into homogeneous lineages by parsimony analysis. The alleles in these lineages were very stable over long evolutionary periods. Some alleles derived from mice and rats have the same sequence motifs, indicating that they have been retained as polymorphisms since prior to the separation of the genus Mus and Rattus (10 Myr). Our findings indicate that polymorphism of MHC class II genes are generated by a combination of two processes. The steady accumulation of point mutations has produced highly divergent polymorphic sequence motifs in each sub-domain. This diversity is extensively amplified by repeated intra-exonic recombinations that shuffle these polymorphic sequence motifs into many, novel, allelic combinations. These intra-exonic recombinational events do not seem to occur at a extraordinary rate, or at specific sites within the exon. The protein sequences encoded by the polymorphic sequence motifs differed on average in 39.3% of amino acids and 67.3% of these substitutions were non-conservative. These findings indicate that they encode protein segments in the antigen binding site with distinct chemical properties. Codons for the antigen binding site have accumulated more non-synonymous (amino acid replacement) substitutions than synonymous (silent) substitutions, whereas the opposite is true for the non-antigen binding site codons in exon 2. All these results suggest that diversity is selectively maintained within the antigen binding sites. We propose that a special mechanism (termed divergent allele advantage), together with overdominant selection, accounts for the maintenance of a large number of highly divergent alleles in natural mouse populations. The extraordinary conservation of sequence motifs suggest that purifying selection may operate on MHC genes to selectively maintain certain sequence motifs and possibly combinations of specific motifs.
LIS Graduate Students as Library Users: A Survey Study

Abstract Library and information science (LIS) students at the University of Illinois, Urbana-Champaign, were surveyed to ascertain their patterns of library use and their perceptions of the value of various library services. The data reveals similarities and differences to previously studied general graduate student populations, at both Illinois and other universities. The analysis highlights differences between distance and on-campus students, an important division in LIS professional education. Beyond the utility of the findings for understanding the information needs and behaviors of the target population, the study sheds light on pre-professional LIS students' use of libraries and their attitudes toward services they are being trained to provide.
Lipid content of maturing ovaries of Aedes aegypti mosquitoes

Abstract 1. 1. Before yolk is deposited, hydrocarbons and fatty esters comprise the principal ovarian lipids. However, during the initial (micropinocytosis) stage of oogenesis, triglycerides accumulate rapidly to become predominant. 2. 2. Simultaneously, phospholipids increase to a lesser extent, involving an absolute increase in phosphatidylcholine and a relative decrease in phosphatidylethanolamine and diphosphatidylglycerol. 3. 3. The principal increase in oocyte volume follows cessation of micropinocytosis and this is paralleled by an increase in dry weight, indicating that hydration does not account for this trophic phase of development. 4. 4. Less than a third of this increased dry weight is represented by lipid, most of which is hydrocarbon and fatty ester. 5. 5. Phospholipid comprises a small portion of the lipid in mature eggs and includes most known phosphoglycerides except sphingomyelin.
Steady state droplet coalescence

Abstract Simple models for droplet deposition and coalescence in which droplets exceeding a predetermined size ( s ∗ ) are either completely or partially removed, have been investigated. The approach of the mean droplet size S(t) to its steady state value can be represented by the scaling form S(t) = s ∗ f(s ∗− 1 z t ) where the exponent z has the value of D (D − d) for the deposition of D-dimensional droplets onto a d-dimensional substrate. Similarly, the steady state droplet size distribution Ns (∞) can be represented quite well by the scaling form N s (∞) = s ∗Θ f( s s∗ ) where the exponent ʐ has a value of (D + d) D . If the large droplets arc completely removed, both S(t) and N(t) exhibit damped oscillations before the steady state is reached. If only the excess mass (>;s∗) is removed, the approach to steady state is monotonic.
The phase diagram and morphology of blends of poly(vinylidene fluoride) and poly(ethyl acrylate)

Abstract The phase diagram and crystallization behaviour of the polymer blend system consisting of poly(vinylidene fluoride) (PVF 2 ) and poly(ethyl acrylate) (PEA) have been examined. The melt exhibits phase separation upon heating to 10°C–50°C above the melting point of the PVF 2 , depending on the composition. The cloud point and equilibrium melting point curve (for α-PVF 2 ) intersect at about 180°C and a composition of 50% (by weight) PVF 2 . The polymer-polymer interaction parameter, χ, was calculated from the equilibrium melting point depression data and found to be −0.16 (at 170°C). Spherulite growth rate data have been measured as a function of composition and temperature. Assuming regime II crystallization a value of the product of the surface free energies of the α-PVF 2 crystals was calculated to be 4.4 × 10 −4 J 2 m −4 . In blends crystallized from the one phase melt the texture of spherulites becomes more open and the spherulite extinction ring spacing (due to lamaller twist) becomes larger with increasing crystallization temperature. In addition the ring spacing increases with PEA content at constant crystallization temperature.
DEPENDENCE OF THE TRIPLET YIELD ON EXCITATION ENERGY IN ALL‐TRANS AND 11‐CIS RETINAL*

. The triplet-triplet absorption of all-trans and 11-cis retinal was measured as a function of the exciting radiation from 423 nm to 365 nm in a glass of 3-methylpentane at 77 K. This experiment was also accomplished with all-trans retinal in hexane at ambient temperature. The relative triplet formation quantum yields of all-trans and 11-cis retinal at 77 K were found to be independent (±10%) of the frequency of the exciting radiation. At room temperature we measured an increase in this relative quantum yield for all-trans retinal from 1.0 at 365 nm to 1.82 at 423 nm [Bensasson et al. (1975) measured an absolute quantum yield of 0.45 at 353 nm]. These results are used to evaluate previous interpretations for photophysical decay processes in all-trans retinal, and previous suggestions for wavelength dependent radiationless transitions are shown to be unacceptable. High energy excitation of 300 K solutions of all-trans retinal produce excited states that result in less efficient intersystem crossing. These states appear to be inaccessible in the 77 K matrices. We suggest that steric restrictions introduced by the retinal matrix interaction at 77 K are able to block this new internal conversion pathway back to the ground state.