cssi/SciSciGPT-SciSciNet huggingface dataset:
An expanding family of archaeal transcriptional activators.

Transcriptional regulation in the archaea involves a mosaic of DNA-binding proteins frequently (although not exclusively) of bacterial type, modulating a eukaryal-type core transcription apparatus. Methanocaldococcus jannaschii (Mja) Ptr2, a homologue of the Lrp/AsnC family of bacterial transcription regulators that are among the most widely disseminated archaeal DNA-binding proteins, has been shown to activate transcription by its conjugate hyperthermophilic RNA polymerase. Here, two in vitro systems have been exploited to show that Ptr2 and a Lrp homologue from the thermophile Methanothermococcus thermolithotrophicus (Mth) activate transcription over a ≈40°C range, in conjunction with their cognate TATA-binding proteins (TBPs) and with heterologous TBPs. A closely related homologue from the mesophile Methanococcus maripaludis (Mma) is nearly inert as a transcriptional activator, but a cluster of mutations that converts a surface patch of Mma Lrp to identity with Ptr2 confers transcriptional activity. Mja, Mth, and Mma TBPs are interchangeable for basal transcription, but their ability to support Lrp-mediated transcriptional activation varies widely, with Mja TBP the most active and Mth TBP the least active partner. The implications of this finding for understanding the roles of TBP paralogues in supporting the gene-regulatory repertoires of archaeal genomes are briefly noted.
Susceptibility of immature stages of Chrysoperla rufilabris (Neurop., Chrysopidae) to pyriproxyfen, a juvenile hormone analog.

Effects of pyriproxyfen (Knack), a juvenile analog, at three concentrations (10, 50 and 100 mg [AI]/l), on survival and development of all immature stages of Chrysoperla rufilabris (Burmeister), were determined in the laboratory. Pyriproxyfen significantly reduced the survival rates when eggs, first and third instars were treated, but not when the second instars and pupae were treated. When eggs were treated, the two higher concentrations reduced the eggs viability by 33.3-50%, and only 0.0-6.7% developed to adults. The lowest concentration of pyriproxyfen (10 mg [AI]/l) caused high mortality on third instars, not on other stages, indicating the third instar was the most vulnerable stage. Pyriproxyfen had significant effects on development for all immature C. rufilabris that successfully developed to adults with variations among the developmental stages and concentrations. The overall developmental duration from eggs to adults when eggs, first, and third instars were treated were 2.6-4.2, 2.4-4.1 respectively, and 6.0-7.1 d longer than those in water control, respectively. However, the overall developmental durations from eggs to adults were 0.5-1.2 d shorter than in water control when the second instars were treated with pyriproxyfen. The compatibility of pyriproxyfen with natural enemies in integrated pest management programs is discussed.
Doing the Dirty Work Gender, Race, and Reproductive Labor in Historical Perspective

The concept of reproductive labor is central to an analysis of gender inequality, including understanding the devaluation of cleaning, cooking, child care, and other “women's work” in the paid labor force. This article presents historical census data that detail transformations of paid reproductive labor during the twentieth century. Changes in the organization of cooking and cleaning tasks in the paid labor market have led to shifts in the demographics of workers engaged in these tasks. As the context for cleaning and cooking work shifted from the dominance of private household servants to include more institutional forms, the gender balance of this reproductive labor workforce has been transformed, while racial-ethnic hierarchies have remained entrenched. This article highlights the challenges to understanding occupational segregation and the devaluation of reproductive labor in a way that analyzes gender and race-ethnicity in an intersectional way and integrates cultural and structural explanations of ...
Overcoming Graduate Students' Negative Perceptions of Statistics.

Although there has been some attention in the literature to such issues as students' attitudes toward statistics, instructors are still constantly faced with the challenge to engage students; understand their perceptions, motivations, and interests; and deal with their reluctance and negative attitudes toward the field of statistics. The purpose of the present study was to (1) examine students' attitudes toward statistics; (2) identify characteristics of students with the most negative attitudes toward statistics; (3) determine methods of statistics instruction that students most prefer; and (4) present strategies to overcome fears, resistance, anxiety, and negative attitudes and enhance the learning environment. The findings from the study of 195 graduate social work students demonstrate that factors contributing to statistics anxiety include math phobia, lack of relevance to social work, instructor's characteristics, and classroom environment. Among the preferred instructional methods students identifie...
CORRELATION BETWEEN GENETIC DIFFERENCES AND DEVELOPMENT OF POLYCYTHEMIA-ANEMIA IN MOUSE PARABIONTS.

Summary1. BALB/c mice were placed in parabiotic union with 4 related (A, C3H, CBA, and DBA/2) and 2 unrelated (C57 BL/6 and C57BR) strains of mice. Hematocrits were read at 2-day intervals for a total period of 10 days. 2. The BALB/c para-bionts showed the same or an increased hematocrit at the 4th day of parabiosis while their homologous partners showed varying degrees of anemia, 3. Hematocrit differences between the BALB/c and homologous para-bionts increased with increasing genetic differences. 4. Seventy-one percent BALB/c mice (tolerant to BALB/c skin grafts) in parabiosis with isologous mice showed increased hematocrits at 4 days. This increase was maintained in 35% of the tolerant pairs.
OH, HO2, and OH reactivity during the PMTACS–NY Whiteface Mountain 2002 campaign: Observations and model comparison

[1] Hydroxyl (OH), hydroperoxy (HO2) radicals, collectively known as HOx, and OH reactivity, were measured during the PMTACS–NY (PM2.5 Technology Assessment and Characteristics Study-New York) summer 2002 intensive at Whiteface Mountain, Wilmington, New York. The measurement results of OH and HO2 for 4 weeks are presented. Diurnal cycles show that the average noontime maximum mixing ratios were about 0.11 pptv (2.6 × 106 cm−3) for OH and 20 pptv for HO2. Measured HO2 to OH ratios were typically between 40 and 400, which are greater than those obtained in polluted and semipolluted rural environments. Low but significant mixing ratios of OH and HO2 persisted into early evening and were frequently observed during nighttime, consistent with previous studies in different environments. Steady state OH and HO2 were calculated with a zero-dimensional chemical model using a complete Regional Atmospheric Chemical Mechanism (RACM) and a parameterized RACM which was constrained to the measured OH reactivity. Good agreement was obtained between the complete RACM and the parameterized RACM models. On average, the complete RACM model reproduced the observed OH with a median measured-to-modeled OH ratio of 0.82 and daytime HO2 with a median measured-to-modeled HO2 ratio of 1.21. The reasonably good agreement in this study is inconsistent with the significant underestimation of OH in the Program for Research on Oxidants: Photochemistry, Emissions, and Transport in 1998 (PROPHET98) study at a similar forested site. HOx budget analysis indicates that OH was primarily from the photolysis of HONO and O3 during the day and from O3 + alkenes reactions at night. The main HOx loss was the self reaction of HO2. The good agreement between the measured and calculated OH reactivity in this environment contrasts with findings in the PROPHET2000 study, in which significant OH reactivity was missing and the missing OH reactivity was temperature-dependent.
The 1988 Antarctic ozone depletion: Comparison with previous year depletions

The 1988 spring Antarctic ozone depletion was observed by TOMS to be substantially smaller than in recent years. The minimum polar total ozone values declined only 15 percent during September 1988, compared to nearly 50 percent during September 1987. At southern midlatitudes, exceptionally high total ozone values were recorded beginning in July 1988. The total integrated southern hemispheric ozone increased rapidly during the Austral spring, approaching 1980 levels during October. The high midlatitude total ozone values were associated with a substantial increase in eddy activity as indicated by the standard deviation in total ozone in the zonal band 30-60 deg S. Mechanisms through which the increased midlatitude eddy activity could disrupt the formation of the Antarctic ozone hole are briefly discussed.
Interspecific amphiploid‐derived alloplasmic male sterility with defective anthers, narrow disc florets and small ray flowers in sunflower

The cytoplasmic male-sterility (CMS)/fertility-restoration system is important for hybrid sunflower (Helianthus annuus L.) seed production. The objective of this study was to characterize two novel alloplasmic CMSs, designated CMS GRO1 and CMS MAX3, with defective anthers, narrow disc florets with no swollen corolla, and short, narrow ray flowers derived from two tetraploid amphiploids (AMPs). Among 26 tested lines, only AMP Helianthus cusickii/P 21 and HA 410 failed to restore male-fertility. Segregation of CMS, male-fertile plants and plants with reduced male-fertility was observed both in the testcross progeny of a six line half-diallel cross of F1s with CMS MAX3 and in an F2 population of CMS GRO1 × RHA 274. Male-fertility restoration was controlled by at least two dominant genes. Detailed analysis of the mitochondrial genes may provide insight into the differences between these CMSs and other CMS lines. The new CMSs will facilitate the studies of the incompatibility between cytoplasmic and nuclear genes, especially for the alloplasmic CMS involving perennial species, and also provide unique ornamental flower types and CMS sources for hybrid sunflower breeding.
Lithium crystal properties from high-quality Hartree-Fock wave functions

Abstract Properties derived from lithium b.c.c. crystal Hartree-Fock (HF) calculations, using LCAO-type Bloch functions and including 2 s , 2 p and 3 d Slater-type basis orbitals, are presented. These include total energies, lattice parameters, band gaps, widths of the occupied part of valence band, bulk modulus and Fermi surface geometry. Energetic quantities are in qualitative agreement with our earlier work. Their disagreements with experiment again underscore some inadequacies of HF. The bulk modulus is overestimated by about 50%, which is typical for HF-based molecular force constants. The Fermi surface is calculated to have a maximum distortion (in the 〈110〉 direction) of about 3.5%. This is in agreement with the best experiments. The sensitivity of predicted distortions to Brillouin zone integration points is discussed.
Spectral broadening and population relaxation in a GaAs interfacial quantum dot ensemble and quantum well nanostructure

Optical two-dimensional Fourier transform spectroscopy (2DFTS) is used to measure thermal broadening of the ground state exciton homogeneous linewidth and energy relaxation in a single layer of interfacial GaAs quantum dots (QDs). We observe a nonlinear increase in the homogeneous linewidth with temperature from 6 to 50 K and find that a phonon activation term + offset fit the data well. The absence of an activation peak in the 2D spectra indicates that elastic exciton–phonon scattering via virtual transitions between the ground and excited states significantly contributes to the thermal broadening. Measurements of the linewidth across the inhomogeneous distribution show that excitons localized in smaller QDs experience stronger thermal broadening. We record 2D spectra for a population time up to 500 ps and temperature up to 50 K to reveal excitonic relaxation from quantum well to QD states. As the temperature increases from 6 to 50 K, the relaxation time decreases from 180 to 30 ps, respectively. This behavior is consistent with a phonon-mediated scattering process.
Application of Artificial Pigments to Structure Determination and Study of Photoinduced Transformations of Retinal Proteins

The protonated Schiff bases of all-trans-retinal and its double bond isomers, 11-cis- and 13-cis-retinals, comprise the chromophores of bacteriorhodopsin, sensory rhodopsin, rhodopsin, and the Chlamydomonas photoreceptor pigment. Absorption of photons by these chromophores is directly responsible for the functioning of the various photopigments. Clarification of their extremely complex structures and mechanisms requires multidisciplinary collaboration. The study of synthetic retinal analogs and pigments reconstituted from analogs provides a powerful and indispensable tool for such clarification. This article summarizes the application of retinal analogs in the bioorganic, biophysical, and biochemical investigations of the various retinal pigments.
Assessing the mechanical strength of interfacial atomic bonds by quantitative high-resolution transmission electron microscopy

Abstract A method is presented for quantitatively assessing the strength of interatomic bonding forces across interfaces between two dissimilar crystalline materials. At such interfaces, the mismatch of corresponding lattice parameters gives rise to a periodic pattern of linear regions of poor match, denoted as ‘misfit dislocations’. The atom displacements that occur in these regions constitute an ‘image’ of the bonding forces across the interface. By fitting a model of the displacement field to experimentally determined atom positions at misfit dislocation cores, therefore, it should be possible to assess the mechanical strength of the interatomic bonds across the interface. The feasibility of this approach is demonstrated for the cube-on-cube interface between a SrTiO3(001) substrate and an epitaxial layer of SrZrO3. The atom positions at the misfit dislocations in this interface were determined with small error limits (0.03 nm) by quantitative high-resolution transmission electron microscopy. By fittin...
Accelerated gene evolution and subfunctionalization in the pseudotetraploid frog Xenopus laevis

Ancient whole genome duplications have been implicated in the vertebrate and teleost radiations, and in the emergence of diverse angiosperm lineages, but the evolutionary response to such a perturbation is still poorly understood. The African clawed frog Xenopus laevis experienced a relatively recent tetraploidization ~40 million years ago. Analysis of the considerable amount of EST sequence available for this species together with the genome sequence of the related diploid Xenopus tropicalis provides a unique opportunity to study the genomic response to whole genome duplication. We identified 2218 gene triplets in which a single gene in X. tropicalis corresponds to precisely two co-orthologous genes in X. laevis – the largest such collection published from any duplication event in animals. Analysis of these triplets reveals accelerated evolution or relaxation of constraint in the peptides of the X. laevis pairs compared with the orthologous sequences in X. tropicalis and other vertebrates. In contrast, single-copy X. laevis genes do not show this acceleration. Duplicated genes can differ substantially in expression levels and patterns. We find no significant difference in gene content in the duplicated set, versus the single-copy set based on molecular and biological function ontologies. These results support a scenario in which duplicate genes are retained through a process of subfunctionalization and/or relaxation of constraint on both copies of an ancestral gene.
Physician Understanding of Patient Health Beliefs

To the Editors:–Street and Haidet appropriately position physician understanding of patient health beliefs as a key feature of patient-centered care (How well do doctors know their patients? Factors affecting physician understanding of patients’ health beliefs).1 They make a compelling argument for the value of shared understanding, and provide evidence that consonance regarding health beliefs is more likely to be achieved if patients ask questions, express concerns, and offer opinions about their health during a medical encounter. Of course, health beliefs are just one of the many domains for which shared understanding is critical. At least as fundamental as patients’ beliefs about a health problem are their beliefs about health per se. For instance, physicians cannot be expected to successfully counsel patients for better health unless they understand how their patients think about health. In national surveys, we elucidated four distinct and robust conceptions of health in America: capacity (health is an enabling factor); control (health is the result of an individual’s behaviors); physical (health is completely physical, focused on the body and biomedical criteria); psychosocial (health is a mix of mental, emotional, social, and spiritual factors).2 The importance of assessing and addressing how people define health was reinforced by the finding that 30% of the overall survey sample did not view health as physical, suggesting that shared understanding about “health” is another important marker of truly patient-centered care.
An initial study of hexavalent phosphazene salts as draw solutes in forward osmosis

Abstract Two novel multi-valent salts based on phosphazene chemistry have been synthesized and characterized as forward osmosis (FO) draw solutes. Commercially obtained hexachlorocyclotriphosphazene was reacted with the sodium salt of 4-ethylhydroxybenzoate to yield hexa(4-ethylcarboxylatophenoxy)phosphazene. Hydrolysis, followed by neutralization with NaOH or LiOH of the resulting acidic moieties yielded water soluble sodium and lithium phosphazene salts, respectively. Degrees of dissociation were determined through osmometry over the range of 0.05–0.5 m, giving degrees of 3.08–4.95 per mole, suggesting a high osmotic potential. The Li salt was found to be more ionized in solution than the sodium salt, and this was reflected in FO experiments where the Li salt gave higher initial fluxes (~ 7 l/m2 h) as compared to the sodium salt (~ 6 l/m2 h) at identical 0.067 m draw solution concentrations at 30 °C. Longer term experiments revealed no detectable degradation of the salts; however some hydrolysis of the cellulose acetate membrane was observed, presumably due to the pH of the phosphazene salt draw solution (pH = ~ 8).
Modeling acute traumatic injury

Acute traumatic injury is a complex disease that has remained a leading cause of death, which affects all ages in our society. Direct mechanical insult to tissues may result in physiological and immunologic disturbances brought about by blood loss, coagulopathy, as well as ischemia and reperfusion insults. This inappropriate response leads to an abnormal release of endogenous mediators of inflammation that synergistically contribute to the incidence of morbidity and mortality. This aberrant activation and suppression of the immune system follows a bimodal pattern, wherein activation of the innate immune responses is followed by an anti-inflammatory response with suppression of the adaptive immunity, which can subsequently lead secondary insults and multiple organ dysfunction. Traumatic injury rodent and swine models have been used to describe many of the underlying pathologic mechanisms, which have led to an improved understanding of the morbidity and mortality associated with critically ill trauma patients. The enigmatic immunopathology of the human immunologic response after severe trauma, however, has never more been apparent and there grows a need for a clinically relevant animal model, which mimics this immune physiology to enhance the care of the most severely injured. This has necessitated preclinical studies in a more closely related model system, the nonhuman primate. In this review article, we summarize animal models of trauma that have provided insight into the clinical response and understanding of cellular mechanisms involved in the onset and progression of ischemia-reperfusion injury as well as describe future treatment options using immunomodulation-based strategies.
Neural network for inferring the shape of occluded objects

Two different approaches have been implemented to model the filling-in procedure for inferring the shape of occluded objects: computational and back-propagation network. The two approaches have been found to have functional similarities. The receptive fields of the units have been analyzed and an analogy with the receptive field of neurons in area V2 of visual cortex was suggested.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Latitudinal Effect on Respiration in some Northern Plants.

Comparative measurements have been made on a great many species of cold-blooded animals from different latitudes, and generally it has been found that the aquatic forms that live in the Arctic respire at a higher rate for a given temperature than those from more southern latitudes. Among terrestrial insects, however, such a metabolic compensation either has not been found or is very much less pronounced, indicating perhaps that insects can to some extent select favorable microclimates (1, 9). That at least some of them are capable of compensating has been demonstrated in the case of cockroaches by keeping them for prolonged periods at low temperatures (3).
Transcriptional Targets of the Vitamin D3 Receptor–Mediating Cell Cycle Arrest and Differentiation

We are exploring the mechanism of action of the hormonal form of the nutrient vitamin D, 1,25(OH)2D3, and its cognate nuclear receptor at the level of gene control. In doing so, we have focused on a dual track as follows: 1) to define the vitamin D3 receptor (VDR) function and structure by examining its various actions at the molecular level; and 2) to isolate and characterize VDR target genes that might be playing key roles in mediating vitamin D growth suppression and differentiation in responsive cells, specifically, the elucidation of vitamin D target genes as they relate to myeloid differentiation. Here, we will summarize some of our recent results from both tracks because a detailed understanding of how VDR functions as a ligand-regulated transcription factor will allow us to study its actions on these newly discovered genes more effectively.
Incidental Learning of Sight Words During Articulation Training

The present study examined the acquisition of sight reading vocabulary learned incidentally during articulation training. A multiple probe design across behaviors with reinforced probe conditions w...
Optimization-based estimation of random distributed parameters in elliptic partial differential equations

As simulation continues to replace experimentation in the design cycle, the need to quantify uncertainty in model outputs due to uncertainties in the model parameters becomes critical. For distributed parameter models, current approaches assume the mean and variance of parameters are known, then use recently developed efficient numerical methods for approximating stochastic partial differential equations. However, the statistical descriptions of the model parameters are rarely known. A number of recent works have investigated adapting existing variational methods for parameter estimation to account for parametric uncertainty. In this paper, we formulate the parameter identification problem as an infinite dimensional constrained optimization problem for which we establish existence of minimizers and the first order necessary conditions. A spectral approximation of the uncertain observations (via a truncated Karhunen-Loeve expansion) allows an approximation of the infinite dimensional problem by a smooth, albeit high dimensional, deterministic optimization problem, the so-called ‘finite noise’ problem, in the space of functions with bounded mixed derivatives. We prove convergence of ‘finite noise’ minimizers to the corresponding infinite dimensional solutions, and devise a gradient based strategy for locating these numerically. Lastly, we illustrate our method with a numerical example.
Sex Differences in Self-awareness of Smiling During a Mock Job Interview

The present study examined sex differences in awareness of smiling behavior during a job interview, along with intended outcomes of false smiling. Male and female participants were assigned to the interviewee role of a mock job interview and were videotaped. Results indicate that women were more self-aware of false, but not genuine, smiling. In addition, women reported using false smiles to mask negative emotion and to appear enthusiastic more than did men. Naive judges rated women who smiled in an attempt to mask negative emotion more harshly than men who smiled for this reason. Implications of these findings for the understanding of sex differences in smiling are discussed.
On the discovery of critical links and nodes for assessing network vulnerability

The assessment of network vulnerability is of great importance in the presence of unexpected disruptive events or adversarial attacks targeting on critical network links and nodes. In this paper, we study Critical Link Disruptor (CLD) and Critical Node Disruptor (CND) optimization problems to identify critical links and nodes in a network whose removals maximally destroy the network's functions. We provide a comprehensive complexity analysis of CLD and CND on general graphs and show that they still remain NP-complete even on unit disk graphs and power-law graphs. Furthermore, the CND problem is shown NP-hard to be approximated within Ω([(n-k)/(ne)] ) on general graphs with n vertices and k critical nodes. Despite the intractability of these problems, we propose HILPR, a novel LP-based rounding algorithm, for efficiently solving CLD and CND problems in a timely manner. The effectiveness of our solutions is validated on various synthetic and real-world networks.
A DELURY DEPLETION ESTIMATOR FOR WALLEYE POLLOCK (THERAGRA CHALCO‐GRAMMA) IN THE EASTERN BERING SEA

. Concerns about local depletion of fish populations are intensifying, as interest becomes focused on finer spatial and temporal scales. We used the DeLury model to investigate local depletion of the eastern Bering Sea walleye pollock population by its fishery by using spatial and temporal scales thought to meet assumptions about closure and applicability. Local depletion is estimated as the slope of logarithmic catch-per-unit-effort (CPUE) from the fishery versus cumulative effort, with data from 1995 1999 stratified by small areas, short seasons and years. Of 237 depletion estimators, 172 had negative slopes, 94 of which were significant, a greater number than would be expected by chance alone. Of the 65 positive slopes, 19 were significantly positive, which is also more than would be expected. Cumulative depletion over a season was inversely related to estimated initial biomass, total catch, and total effort, indicating that depletion is detected more easily in areas of low abundance and consequently lower catch and effort. Our fine-scale estimates of depletion are much smaller than the overall depletion from annual stock assessments, showing that commercial data alone can be at best a relative index of depletion. This hyperstable relationship may result from the lack of search time in the measure of effort, fish finding technology and schooling behavior of pollock. Evidence also suggests that measures that were taken starting in 1999 to disperse the exploitation pressure in space and time may decrease local depletion, and that pollock may repopulate an exploited area in a relatively short time period (weeks).
Efficacy of antimicrobial-impregnated silicone sections from penile implants in preventing device colonization in an animal model.

Abstract Objectives. To assess, in an animal study, the efficacy of minocycline/rifampin-impregnated silicone sections of pump bulbs from penile implants in preventing device colonization by Staphylococcus aureus. Infection constitutes a very serious complication of penile implants. Methods. Minocycline/rifampin-impregnated and control silicone pump bulb sections from penile implants were each inoculated with about 103 to 104 colony-forming units of S. aureus. After 8 hours of incubation with bacteria at room temperature, the test devices were allowed to dry for 30 minutes, and then subcutaneously implanted in the backs of rabbits. Eleven rabbits each received a total of six devices. The wounds were sutured, and the rabbits were monitored daily, then killed at 2 days after surgery. In vitro zones of inhibition against S. aureus by the minocycline/rifampin-impregnated and control devices were also determined. Results. All of the six tested antimicrobial-impregnated devices but none of the control devices produced zones of inhibition in vitro against S. aureus (mean zone of inhibition by antimicrobial-impregnated devices of 23 mm). The antimicrobial-impregnated devices retrieved from rabbits were sixfold less likely than were the control devices to be colonized with S. aureus (2 [6%] of 33 versus 11 [33%] of 33, respectively; P = 0.011). Conclusions. The results of this animal study indicate that minocycline/rifampin-impregnated pump bulb sections from penile implants provide antimicrobial activity in vitro against S. aureus and protect against staphylococcal colonization of devices implanted for 2 days in animals.
Asymmetric Recovery from Wet versus Dry Soil Moisture Anomalies

Abstract The energy and moisture state in the soil and new-surface atmosphere evolve due to fluxes that are themselves a function of these states. Because the soil moisture and temperature are negatively correlated (dry warm or cool moist), physical mechanisms that tend to restore each state individually (soil moisture control of evaporation and temperature dependence of saturation specific humidity, for example) act as anomaly enhancing (positive) feedback mechanisms for the other state. Model and observational studies in the literature indicate that dry hydrologic anomalies tend to persist longer than moist ones, suggesting that thee feedback mechanisms are stronger when the soil layer is dry. A conceptual land-atmosphere model, consisting of heat and moisture balance for a soil layer and a turbulently mixed atmospheric boundary layer, is subjected to stochastic forcing. The covariability structure evolves through the state-dependent turbulent and radiative fluxes in the land-atmosphere system and is no...
Influence of material properties on dynamic fracture toughness of steels

Abstract Recent studies of plastic enclave formation at running brittle cracks were extended to account for the influence of crack tip boundary conditions on the temperature at which the enclaves start to develop. The En 2A and three other steels were used in the analysis. It was found that this temperature depends very strongly both on the magnitude and on the distribution of the stresses in the discrete crack tip zone. This suggests that the onset of enclave formation and the rate of their growth are governed by the balance of two sets of material characteristics. The first set consists of at least two parameters describing the microscopic fracture resistance which promotes enclave formation. The second set includes the macroscopic yield and flow properties which may make enclave formation more difficult in higher strength steels. These findings are related to the dynamic or crack arrest fracture toughness which is found to be derived from two different sources. One is connected with the microscopic plastic deformation of the fracturing metal in the crack tip zone and is present at all temperatures. The other is the result of enclave formation, it is present only at higher temperatures and is responsible for the energy transition. In contrast to the case of crack initiation, the dynamic fracture toughness depends not only on the microscopic fracture strength or strain but on the complete stress-displacement relationship of the weakened material which is governed by the microscopic fracture mechanism at the tip of a running crack. It is noted that the present results can be expected to be valid for all steels which fracture in the cleavage or quasi-cleavage modes.
What it Means to Interpret: A Standard Formulation and its Implicit Corollaries in Chinese Buddhism

This study asks two related questions. First, how did the Chinese Buddhists generally think of the nature of interpretation? Second, how did they address the issue of inconsistency inherent in their answer to the first question? The first answer is straightforward, for the model of "truth, teaching, and interpretation" is widely accepted as the "standard formulation" of the nature of interpretation. This answer, however, has an obvious flaw: if the very reason why teaching requires interpretation lies in its unavoidable dependence on intellection, which obstructs its effective transmission of truth, how can interpretation, which is equally if not more reliant on intellection, adequately transmit the truth in a way in which teaching fails? The second answer thus addresses this inconsistency. It argues that while there has never been an explicitly formulated answer to this question, theoretical reflections on unrelated topics seem to have created a general intellectual atmosphere that would allow people to ignore or at least comfortably live with the obvious inconsistency, that is, an atmosphere that would supplement and, in that sense, justify and sustain the answer to the first question; unformulated but supplementary, such theoretical reflections constitute the implicit corollaries of the standard formulation.
Potential of virtual worlds for remote space exploration

A brief description is given for the potential of virtual worlds to remote space exploration and other space-related activities. The major characteristics of current virtual worlds are identified. Recent commercial and open source virtual worlds are listed. Some of the current NASA and other space-related applications of virtual worlds are described, along with some of the tools for virtual space exploration. The technologies and facilities needed to transform the 2D flat internet into a 360^o multi-sensory immersive virtual world experience are identified. A vision is described for a remote space exploration ecosystem (RSEE), which incorporate a massively multi-participant immersive synthetic environment and other advanced facilities, for inspiring and motivating the international community about space activities. High-fidelity visual simulations of future space missions in the immersive synthetic environment and virtual world facilities can engage the public and give them the sense of being there. The future of virtual worlds is bright. Its transformative power is likely to impact many facets of future space programs and missions, and support the concept of collaborative participatory virtual space exploration.
Voluntary exercise increases neurotrophin-3 and its receptor TrkC in the spinal cord

We have evaluated changes in the expression of neurotrophin-3 (NT-3) and its tyrosine kinase C (TrkC) receptor in the neuromuscular system as a result of voluntary physical activity. We assessed changes in the mRNAs and proteins for NT-3 and TrkC in the lumbar spinal cord and associated soleus muscle following 3 and 7 days of voluntary wheel running. We used quantitative Taqman RT-PCR to measure mRNA and ELISA to assess protein levels. NT-3 mRNA and protein levels increased in the spinal cord to reach statistical significance after 7 days of exercise compared to sedentary control rats. Immunohistochemical analyses localized the elevated NT-3 to the substantia gelatinosa (SG) and nucleus of the dorsal horn. TrkC mRNA levels were significantly elevated in the spinal cord after 3 and 7 days of running. In the soleus muscle, NT-3 mRNA levels and its receptor TrkC were elevated after 3 days, while NT-3 protein levels remained unaffected. The results demonstrate that voluntary exercise has a differential effect on NT-3 as well as its receptor TrkC in the neural and muscular components of the neuromuscular system, and emphasize the role of voluntary activity on the spinal cord and muscle.
Effects of loading rate on strength of the proximal femur.

Results from previous quasi-static mechanical tests indicate that femurs from elderly subjects fail in vitro at forces 50% below those available in a fall from standing height. However, bone is a rate-dependent material, and it is not known whether this imbalance is present at rates of loading which occur in a fall. Based on recent data on time to peak force and body positions at impact during simulated falls, we designed a high rate test of the femur in a loading configuration meant to represent a fall on the hip. We used elderly (mean age 73.5±7.4 (SD) years) and younger adult (32.7±12.8 years) cadaveric femurs to investigate whether (1) the strength, stiffness, and energy absorption capacity of the femur increases under high rate loading conditions; (2) elderly femurs have reduced strength, stiffness, and energy absorption capacity compared with younger adult femurs at this loading rate; and (3) densitometric and geometric measures taken at the hip correlate with the measured fracture loads. Femurs were scanned using dual-energy X-ray absorptiometry (DXA) and then tested to failure in a fall loading configuration at a displacement rate of 100 mm/second. The fracture load in elderly and younger adult femurs increased by about 20% with a 50-fold increase in displacement rate. However, energy absorption did not increase with displacement rate because of a twofold increase in stiffness at the higher loading rate. Age-related differences in strength and energy absorption capacity were consistent with those found previously for a displacement rate of 2 mm/second. There were moderate to strong correlations between fracture load and DXA variables, with the best correlation provided by cross-sectional area (r2=0.77) and bone mineral density (BMD) (r2=0.72) at the femoral neck. Our results indicate that, even at rates of loading applied during a fall, the estimated impact force in a fall on the hip is 35% greater than the average fracture load of the elderly femur. Moreover, the relationship we found between femoral neck BMD and fracture load indicates that an increase in femoral neck BMD of more than 20% would be required to raise the strength of the femur to the level of the impact load. As clinical trials of pharmacologic interventions have demonstrated increases in BMD of only a few percent at best, our results emphasize the continuing need for intervention strategies that focus on fall prevention and on reducing the severity of those falls that do occur.
Applications of the Monte Carlo radiation transport toolkit at LLNL

Modern Monte Carlo radiation transport codes can be applied to model most applications of radiation, from optical to TeV photons, from thermal neutrons to heavy ions. Simulations can include any desired level of detail in three-dimensional geometries using the right level of detail in the reaction physics. The technology areas to which we have applied these codes include medical applications, defense, safety and security programs, nuclear safeguards and industrial and research system design and control. The main reason such applications are interesting is that by using these tools substantial savings of time and effort (i.e. money) can be realized. In addition it is possible to separate out and investigate computationally effects which can not be isolated and studied in experiments. In model calculations, just as in real life, one must take care in order to get the correct answer to the right question. Advancing computing technology allows extensions of Monte Carlo applications in two directions. First, as computers become more powerful more problems can be accurately modeled. Second, as computing power becomes cheaper Monte Carlo methods become accessible more widely. An overview of the set of Monte Carlo radiation transport tools in use a LLNL will be presented along with a few examples of applications and future directions.
Measurement and analysis of impact-induced strain using extrinsic Fabry-Pérot fiber optic sensors

In-plane strain responses of surface-mounted extrinsic Fabry-Perot interferometric (EFPI) fiber optic strain sensors are investigated. EFPI fiber optic strain sensors are mounted on three graphite/epoxy laminated composite plates. The plates are impacted with various size steel balls using a drop-weight technique. The impacts did not cause apparent damage. The first impact-induced strain peak was characterized by the rise time, peak value, full width at half maximum and decay time. The transient low-velocity impact response of EFPI fiber optic strain sensors is compared to the response from conventional electrical resistance strain gages and polyvinylidene fluoride (PVDF) piezoelectric film sensors. Orientation dependence and other characteristics of the EFPI fiber optic sensing technique are discussed. An in-house finite element program incorporates geometric nonlinearity and transverse shear deformation for the impact events. The finite element results closely match the experimental strain data for the first peak strain response.
Effect of open microchannel geometry on pool boiling enhancement

Abstract Pool boiling enhancement through surface modification has garnered the attention of many researchers for extending the limits of heat flux dissipation. Simulated copper chips were used in a pool boiling setup with water boiling at atmospheric pressure. Heat transfer performance of different microchanneled surfaces was compared to that of a plain surface. The results of the study showed that the mechanism at work for the bubble dynamics was the ability of the surface to pull liquid through the channels to induce heat transfer. Geometrical trends were observed from the study as well with the wider and deeper channels and thinner finned surfaces showing the best heat transfer results. Without reaching the critical heat flux condition, the best performing chip dissipated a heat flux of 244 W/cm 2 corresponding to a record heat transfer coefficient of 269 kW/m 2 K.
Analysis of No. 50 Taper Joint Stiffness Under Axial and Radial Loading

Abstract This paper is concerned with the joint stiffness characteristics of the standard 7/24 taper interface. Experimental identification of joint stiffness parameters is performed on No. 50 tapers, using a special test setup, by implementing a frequency response function (FRF) based method for joint parameter identification, in conjunction with finite element modeling of the substructure. The effects of axial and radial loading as well as taper wear on the taper joint stiffness are examined. It is shown that taper joint stiffness nonuniformly increases with axial preloading and decreases with radial loading. Validation of the identified stiffness values is given by comparing the predicted natural frequencies of the taper assembly with experimentally measured values.
Context effects on auditory distraction

The purpose of the study was to test the hypothesis that sound context modulates the magnitude of auditory distraction, indexed by behavioral and electrophysiological measures. Participants were asked to identify tone duration, while irrelevant changes occurred in tone frequency, tone intensity, and harmonic structure. Frequency deviants were randomly intermixed with standards (Uni-Condition), with intensity deviants (Bi-Condition), and with both intensity and complex deviants (Tri-Condition). Only in the Tri-Condition did the auditory distraction effect reflect the magnitude difference among the frequency and intensity deviants. The mixture of the different types of deviants in the Tri-Condition modulated the perceived level of distraction, demonstrating that the sound context can modulate the effect of deviance level on processing irrelevant acoustic changes in the environment. These findings thus indicate that perceptual contrast plays a role in change detection processes that leads to auditory distraction.
Functional Contact Lenses for Remote Health Monitoring in Developing Countries

The opportunities afforded by using a functional contact lens for remote wireless health status monitoring are discussed and the progress to date in the development of this technology platform is presented. A functional contact lens complete with sensors and embedded circuitry can be used to monitor the composition of tear fluid and, by extension, a number of health-status related parameters in the body in a noninvasive and continuous fashion. The data collected by the disposable contact lens may be sent wirelessly to a mobile phone that, in turn, can relay the information to a medical practitioner via the cellular phone network. If successfully developed and deployed, such a system can be used for monitoring a variety of health indicators over a large geographic area and population distribution with minimal need for the physical presence of health care providers.
Supernova Remnants in the Magellanic Clouds. VI. The DEM L316 Supernova Remnants

The DEM L316 system contains two shells, both with the characteristic signatures of supernova remnants (SNRs). We analyze Chandra and XMM-Newton data for DEM L316, investigating its spatial and spectral X-ray features. Our Chandra observations resolve the structure of the northeastern SNR (shell A) as a bright inner ring and a set of "arcs" surrounded by fainter diffuse emission. The spectrum is well fit by a thermal plasma model with a temperature of ~1.4 keV; we do not find significant spectral differences for different regions of this SNR. The southwestern SNR (shell B) exhibits an irregular X-ray outline, with a brighter interior ring of emission including a bright knot of emission. Overall, the emission of the SNR is well described by a thermal plasma of temperature ~0.6 keV. The bright knot, however, is spectrally distinct from the rest of the SNR, requiring the addition of a high-energy spectral component consistent with a power-law spectrum of photon index 1.6-1.8. We confirm the findings of Nishiuchi and coworkers that the spectra of these shells are notably different, with shell A requiring a high iron abundance for a good spectral fit, implying a Type Ia origin. We further explicitly compare abundance ratios to model predictions for Type Ia and Type II supernovae. The low ratios for shell A (O/Fe of 1.5 and Ne/Fe of 0.2) and the high ratios for shell B (O/Fe of 30-130 and Ne/Fe of 8-16) are consistent with Type Ia and Type II origins, respectively. The difference between the SNR progenitor types casts some doubt on the suggestion that these SNRs are interacting with one another.
Expression of the leptin receptor during germ cell development in the mouse testis.

Leptin, a recently identified hormonal product of the ob gene, is known to regulate appetite, body metabolism, and reproductive functions. We investigated the expression of the leptin receptor (Ob-R) in testes from different age groups. The messenger RNA for Ob-R was found in testes from all age groups using RT-PCR. Using immunohistochemistry, we observed age- and stage-dependent distribution of the Ob-R in mouse testis. In testis of 5-day-old mice, its expression was mainly in type A spermatogonia. In the 20- and 30-day-old testis, Ob-R expression was in the spermatocytes; in the adult testis, it was specific to spermatocytes in stages IX and X of the cycle of the seminiferous epithelium. Five main immunoreactive proteins were detected using Western blot (220, 120, 90, 66, and 46 kDa). The 120-kDa protein was evident only in 20-day-old and older testes, whereas the 90-kDa band was present only in the 5- and 10-day-old testis. Leptin treatment induced phosphorylation of signal transducer and activator of transcription-3 in cultured seminiferous tubules from adult and 5-day-old testes. Our results show for the first time age- and stagespecific localization of a functional Ob-R in testicular germ cells. We hypothesize a direct role for leptin, through phosphorylation of signal transducer and activator of transcription-3, in proliferation and differentiation of germ cells, which may partially explain the infertility observed in leptin-deficient mice. (Endocrinology 141: 2624 ‐2630, 2000)