cssi/SciSciGPT-SciSciNet huggingface dataset:
The role of DNA polymerases in DNA repair in Escherichia coli: DNA polymerase I-dependent repair following chemical alkylation of permeabilized bacteria.

Abstract Many mutagens and carcinogens damage DNA and elicit repair synthesis in cells. In the present study we report that alkylation of the DNA of Escherichia coli that have been made permeable to nucleotides by toluene treatment results in the expression of a DNA polymerase I-directed repair synthesis. The advantage of the system described here is that it permits measurement of only DNA polymerase I-directed repair synthesis and serves as a simple, rapid method for determining the ability of a given chemical to elicit “excision-repair” in bacteria. DNA ligation is intentionally prevented in our system by addition of the inhibitor nicotinamide mononucleotide. In the absence of DNA ligase activity, nick translation is extensive and an “exaggerated” repair synthesis occurs. This amplification of repair synthesis is unique for DNA polymerase I since it is not observed in mutant cells deficient in this polymerase. DNA ligase apparently controls the extent of nucleotide replacement by this repair enzyme through its ability to rejoin “nicks” thereby terminating the DNA elongation process. The nitrosoamides N -methyl- N -nitrosourea and N -ethyl- N -nitrosourea, as well as the nitrosoamidines N -methyl- N′ -nitro- N -nitrosoguanidine and N -ethyl- N′ -nitro- N -nitrosoguanidine, elicit DNA polymerase I-directed repair synthesis. Methyl methanesulphonate is especially potent in this regard, while its ethyl derivative, ethyl methanesulphonate, is a poor inducer of DNA polymerase I activity in permeabilized cells.
Design of graphene sheets-supported Pt catalyst layer in PEM fuel cells

A series of cathodes using Pt supported onto graphene sheets with different contents of carbon black in the catalyst layer were prepared and characterized. Carbon black was added as a spacer between two-dimensional graphene sheets in the catalyst layer to study its effect on the performance of proton exchange membrane fuel cell. Electrochemical properties and surface morphology of the cathodes with and without carbon black were characterized using cyclic voltammetry, ac-impedance spectroscopy, electrochemical polarization technique, and scanning electron microscopy. The results indicated that carbon black effectively modifies the array of graphene supports, resulting in more Pt nanoparticles available for electrochemical reaction and better mass transport in the catalyst layer.
The cost effectiveness of empiric intravenous immunoglobulin for the antepartum treatment of fetal and neonatal alloimmune thrombocytopenia

Objective The purpose of this study was to compare the cost effectiveness of empiric intravenous immunoglobulin (IVIG) with that of fetal blood sampling–indicated treatment for the antepartum care of fetal and neonatal alloimmune thrombocytopenia. Study design We developed a decision analysis model to compare the cost effectiveness of 2 strategies for treatment of pregnancies in women with a history of fetal and neonatal alloimmune thrombocytopenia and an at-risk fetus: 1) IVIG and corticosteroids as indicated by fetal platelet levels determined by fetal blood sampling (FBS); and 2) empiric IVIG. In the first strategy, FBS is used to measure fetal platelets at 24 weeks of gestation and repeated 6 weeks later to guide pharmacotherapy. In the second strategy, weekly IVIG is empirically administered from 24 weeks' to 37 weeks' gestation. The main outcome measure was the marginal cost per quality-adjusted life years (QALY) gained. Results For every 1000 women with a fetus at risk for recurrent alloimmune thrombocytopenia, empiric therapy, compared with FBS-indicated treatment, decreases perinatal deaths from 31.7 to 11.8 while increasing the number of infants with long-term neurologic deficits from 6.1 to 9.6. These health outcomes translate to 382 QALYs gained with empiric therapy and a cost effectiveness ratio of $32,747 per QALY favoring empiric therapy. In the sensitivity analysis, empiric therapy was not cost effective when the rate of perinatal ICH exceeded 28%. Conclusion Empiric IVIG therapy is a cost-effective strategy for the treatment of women at risk for fetal and neonatal alloimmune thrombocytopenia when the rate of perinatal ICH is less than 28%.
Effective Academic Vocabulary Instruction in the Urban Middle School

In urban middle schools, educators find it challenging to meet the literacy needs of the many struggling readers in their classrooms, including language-minority (LM) learners and students from low-income backgrounds. One strategy for improving these students' reading comprehension is to teach essential academic vocabulary in a meaningful, engaging, and systematic way. This article describes the development and evaluation of an academic vocabulary curriculum for sixth-grade mainstream classrooms with large numbers of LM learners who struggle with comprehension. In a study conducted in 21 sixth-grade classrooms, the curriculum was found to be effective both in improving students' vocabulary and reading comprehension and in supporting teachers' learning about how to teach academic vocabulary. Seven universal learnings for all classrooms are described and illustrated with specific examples of activities, perspectives from teachers, and insights from students, drawn from the study.
Baccalaureate Dental Hygiene Graduates' Perceptions of Community Dental Health Employment*

A survey was conducted on 352 University of Iowa baccalaureate dental hygiene graduates to determine the percentage of graduates that had been employed in community dental health, the percentage that were interested in community dental health, employment, and the respondents' perceptions of community dental health employment as it related to the dental hygienist. Specific findings of the study included: 1. Less than 15 percent of the respondents had been employed in community dental health. 2. Nearly 40 percent of the respondents were interested in community dental health employment. 3. Subjects were more opinionated and had more positive impressions of the intrinsic factors than of the extrinsic factors that affect the dental hygienist's employment in community dental health. 4. Subjects who were interested in and/or who had been employed in community dental health had significantly greater positive impressions of community dental health employment than those not interested.
Measurement of Radiation-Induced Interface Traps Using MOSFETs

The buildup of SiO2-Si interface traps due to radiation was measured by a charge pumping measurement method and by a technique based on the slope of the transistor ln(Id)-Vg characteristics in weak inversion. Both aueasurements make use of MOS transistors. The important differences in the "trap density" obtained from the two measurement methods are discussed. The results of the measurements are interpreted to assess the effect of gamma irradiation on the distribution of interface trap density.
Recovery of bacterial spores and vegetative cells with a miniature spray drier

A laboratory spray drier with a gas flow of 2 to 3 ft3/min was used to dry suspensions containing spores of Bacillus anthracis or cells of Pasteurella tularensis. Dried material was collected in a 1/2-in. diameter cyclone that retained about 97 per cent of the product from the drier. The particle size distributions of the powders varied with the nature of substances in the suspension to be dried; as much as 80 per cent of the mass in particles 5 μ or less in diameter was obtained only when egg yolk was added to the suspensions. Retention of viability was about 90 per cent for B. anthracis spores and these powders contained from 175 to 522 × 109 viable spores/gram. Retention of viability of P. tularensis cells was 0·6 per cent or greater only when the suspension contained a relatively high proportion of stabilizers. With sucrose-skim milk-thiourea stabilizer about 10 per cent recovery of viability was obtained when the proportion of stabilizer solids to other solids was 3 : 1 or 6 : 1. These powders contained 140 × 109 viable cells per gram and the mass median diameter was 6·0 μ. The properties of the powders suggest that spray dried vaccines may be prepared for use either in suspension or in aerosols.
Cercopithecidae from the Pliocene of Saint-Vallier

Abstract The mid-Pliocene mammalian faunal locality of Saint-Vallier has yielded two isolated cercopithecine primate teeth, an I 1 and a dP 3 . Both are most similar is size and morphology to those of macaques, such as the extant Macaca sylvanus , to which species the Saint-Vallier population is referred (perhaps as part of a temporal subspecies M. sylvanus florentina ). Such macaques would have been able to tolerate a cool climate but would probably have required some trees in which to sleep and feed.
PHILOSOPHIES OF THE ENVIRONMENTAL PROTECTION AGENCY IN REGULATING HUMAN EXPOSURE TO CARCINOGENS

Some topics discussed are as follows: cost to society of regulatory action taken by the agency; importance of making a reasonable assessment of hazards before taking regulatory action; problems of the evidence of weak carcinogenicity; estimates of levels of exposure; and tolerances for residues of pesticides on food crops. (HLW)
Two-Gluon Correlations in Heavy-Light Ion Collisions: Energy and Geometry Dependence, IR Divergences, and $k_T$-Factorization

Abstract We study the properties of the cross section for two-gluon production in heavy–light ion collisions derived in our previous paper [1] in the saturation/Color Glass Condensate framework. Concentrating on the energy and geometry dependence of the corresponding correlation functions we find that the two-gluon correlator is a much slower function of the center-of-mass energy than the one- and two-gluon production cross sections. The geometry dependence of the correlation function leads to stronger azimuthal near- and away-side correlations in the tip-on-tip U + U collisions than in the side-on-side U + U collisions, an exactly opposite behavior from the correlations generated by the elliptic flow of the quark–gluon plasma: a study of azimuthal correlations in the U + U collisions may thus help to disentangle the two sources of correlations. We demonstrate that the cross section for two-gluon production in heavy–light ion collisions contains a power-law infrared (IR) divergence even for fixed produced gluon momenta: while saturation effects in the target regulate some of the power-law IR-divergent terms in the lowest-order expression for the two-gluon correlator, other power-law IR-divergent terms remain, possibly due to absence of saturation effects in the dilute projectile. Finally we rewrite our result for the two-gluon production cross-section in a k T -factorized form, obtaining a new factorized expression involving a convolution of one- and two-gluon Wigner distributions over both the transverse momenta and impact parameters. We show that the two-gluon production cross-section depends on two different types of unintegrated two-gluon Wigner distribution functions.
The nationality of a naturalist.

The letter from W. H. Evans and D. Lloyd regarding the nationality of Alfred Russel Wallace as given on my Web site ([1][1]) is accurate as far as it goes, but it does not go far enough (1 Feb., p. [797][2]). Wallace's mother and father were of English and English-Scottish descent, respectively.
Containment and growth of neuroblastoma cells on chemically patterned substrates.

Abstract Patterned substrates offer the promise of controlled positioning and directional guidance of growing neurites. Therefore, they could be useful for constructing small neuronal networks with defined geometry in vitro. We have fabricated chemically patterned substrates using self-assembled monolayer films with a lithographic mask technique and demonstrated the feasibility for geometrically patterning neuroblastoma cells in culture. N -octadecyltrichlorosilane (OTS) was chemically bonded to glass and fused silica substrates, rendering the surface hydrophobic and non-adhesive to cells. Using surface analysis techniques, we have confirmed that OTS films were true monolayers and can be photocleaved from the surface by deep UV irradiation. An adhesive pattern of n -(2-aminoethyl-3-aminopropyl)trimethoxysilane was formed on a selectively irradiated OTS surface via a deep UV lithographic procedure. The chemically patterned surface was then seeded with SK-N-SH human neuroblastoma cells, and cellular attachment and growth were monitored by optical microscopy. The use of 2-dimensional substrates supported the containment and growth of neuroblastoma cells within the pattern for at least 15 days in culture. These chemical patterns may also be useful in controlled arrangements of heart cells or muscle cells on prosthetic implant devices.
Optical absorption and transient photobleaching in solutions of surfactant encapsulated and DNA wrapped single-walled carbon nanotubes

Optical absorption and transient photobleaching in solutions of surfactant encapsulated and DNA wrapped single-walled carbon nanotubes (SWNTs) are studied. Optical transitions between van Hove singularities are red shifted in solutions of DNA wrapped SWNTs compared with transitions in solutions of sodium dodecyl sulfate (SDS) encapsulated SWNTs. This red shift may be due to changes in the local surrounding dielectric constant and corresponding changes in charge screening. Transient photobleaching at the E 11 transition of semiconducting SWNTs is observed in both solutions of SDS encapsulated SWNTs and DNA wrapped SWNTs in response to optical excitation at corresponding E 22 transitions, and the saturation of photobleaching at high excitation intensities greater than 500 W cm -2 is studied. It is found that the photobleaching intensity does not saturate as significantly in solutions of DNA wrapped SWNTs as in solutions of SDS isolated SWNTs. Lastly, using degenerate, delayed pump-probe characterization, the temporal relaxation of excited charge carriers is investigated. Measured decays are characterized by both fast and slow processes. The slow decay time constant across the band gap of semiconducting SWNTs is fit to 120 ps for SDS encapsulated SWNTs and 73 ps for DNA wrapped SWNTs.
Young Investigators: Concerns, Options, and Opportunities.

This paper addresses declining opportunities for young faculty primarily due to reductions or leveling of enrollments coupled with low faculty turnover. Recently, active interest in young investigators or faculty has been expressed within the academic, science, and government communities. The objective of several alternatives discussed is to maintain or improve the nation's research efforts through greater utilization of young investigators. A concomitant feature of this objective is increased employment opportunities, mainly in academia, for young Ph.D.'s. Assumptions related to productivity of young researchers, their propensity to obtain research funds, and various forms of support are reviewed. Data collected from universities by the National Science Foundation formed the basis for the analysis.
PSG masks for diffusions in gallium arsenide

This paper describes the use of phosphosilicate glass (PSG) films as an effective mask against zinc and tin diffusions in gallium arsenide. It is shown that films with a high phosphorus pentoxide content (as much as 30 percent by weight) can be used to obtain adequate crack-free masks against these dopants. Effective masking was obtained for diffusion depths (unmasked regions) up to 10 µ.
Personality traits and concern for privacy: an empirical study in the context of location-based services

For more than a century, concern for privacy (CFP) has co-evolved with advances in information technology. The CFP refers to the anxious sense of interest that a person has because of various types of threats to the person's state of being free from intrusion. Research studies have validated this concept and identified its consequences. For example, research has shown that the CFP can have a negative influence on the adoption of information technology; but little is known about factors likely to influence such concern. This paper attempts to fill that gap. Because privacy is said to be a part of a more general ‘right to one's personality’, we consider the so-called ‘Big Five’ personality traits (agreeableness, extraversion, emotional stability, openness to experience, and conscientiousness) as factors that can influence privacy concerns. Protection motivation theory helps us to explain this influence in the context of an emerging pervasive technology: location-based services. Using a survey-based approach, we find that agreeableness, conscientiousness, and openness to experience each affect the CFP. These results have implications for the adoption, the design, and the marketing of highly personalized new technologies.
Monovalent and unpoised status of most genes in undifferentiated cell-enriched Drosophila testis.

Background Increasing evidence demonstrates that stem cells maintain their identities by a unique transcription network and chromatin structure. Opposing epigenetic modifications H3K27me3 and H3K4me3 have been proposed to label differentiation-associated genes in stem cells, progenitor and precursor cells. In addition, many differentiation-associated genes are maintained at a poised status by recruitment of the initiative RNA Polymerase II (Pol II) at their promoter regions, in preparation for lineage-specific expression upon differentiation. Previous studies have been performed using cultured mammalian embryonic stem cells. To a lesser extent, chromatin structure has been delineated in other model organisms, such as Drosophila, to open new avenues for genetic analyses.
The Dynamic Mobility of Histone H1 Is Regulated by Cyclin/CDK Phosphorylation

The linker histone H1 is involved in maintaining higher-order chromatin structures and displays dynamic nuclear mobility, which may be regulated by posttranslational modifications. To analyze the effect of H1 tail phosphorylation on the modulation of the histone's nuclear dynamics, we generated a mutant histone H1, referred to as M1-5, in which the five cyclin-dependent kinase phosphorylation consensus sites were mutated from serine or threonine residues into alanines. Cyclin E/CDK2 or cyclin A/CDK2 cannot phosphorylate the mutant in vitro. Using the technique of fluorescence recovery after photobleaching, we observed that the mobility of a green fluorescent protein (GFP)-M1-5 fusion protein is decreased compared to that of a GFP-wild-type H1 fusion protein. In addition, recovery of H1 correlated with CDK2 activity, as GFP-H1 mobility was decreased in cells with low CDK2 activity. Blocking the activity of CDK2 by p21 expression decreased the mobility of GFP-H1 but not that of GFP-M1-5. Finally, the level and rate of recovery of cyan fluorescent protein (CFP)-M1-5 were lower than those of CFP-H1 specifically in heterochromatic regions. These data suggest that CDK2 phosphorylates histone H1 in vivo, resulting in a more open chromatin structure by destabilizing H1-chromatin interactions.
Musings on Doctoral Education in Social Work

After summarizing the recent initiatives and recommendations about doctoral education by the American Association of Universities and the Woodrow Wilson Fellowship Foundation, this article reviews selected trends in doctoral education in social work. It recommends five foci for further emphasis: promoting interdisciplinary preparation; strengthening the quality of faculty; balancing rigorous research with effective teaching; developing postdoctoral education in institutions with the infrastructure to do so; and fashioning an institutional culture that is hospitable to excellence in social work education.
Scanning electron microscopy of changes in epidermal structure occurring during the shedding cycle in squamate reptiles.

Previous studies of squamate epidermal structure have focused on either histology and ultrastructure or oberhautchen surface texture as revealed by scanning electron microscopy (SEM). Using SEM data drawn from a variety of lizard taxa (primarily iguanids, but also agamids, chamaeleonids, and scincids), as well as amphisbaenians and colubrid snakes, we relate the surfaces encountered in gross dissection of squamate skin to histologically identifiable layers, and characterize their surface structure. Only the oberhautchen bears the repeating pattern of ornamentation noted by previous authors. Because the clear layer is a perfect template of the oberhautchen surface, it is the only layer with which the oberhautchen might be confused. However, the clear layer can be identified by its tendency to curl and crack during preparation. All other surfaces encountered were relatively featureless, except for impressions left by dermal "papillae" associated with mechanoreceptors. Using a method for examining preserved specimens to determine the stage in the shedding cycle, we assess two sources of variation in epidermal surface structure: stage in the shedding cycle and wear. Examination of immature renewal-phase epidermis suggests that the oberhautchen does not mature synchronously across a single scale or across body regions. Comparing inner- and outer-generation oberhautchen in sheddingphase epidermis, we conclude that changes in surface appearance caused by natural wear fall into two categories: discrete scratches and accumulation of debris. We see no evidence of overall "buffing" on a microscopic level, though surface structure may be obscured by scratches and gouges. Many squamate taxa show a gradient from low relief surface structure on elevated regions such as keels to high relief patterns at scale edges. This gradient is not due to wear; its significance is unknown.
Sample size requirements for estimation of throughfall chemistry beneath a mixed hardwood forest

Six rainfall events were intensively sampled below a mixed hardwood forest canopy in central Pennsylvania to determine sample size requirements for estimation of thronghfall volumes and ionic concentrations. Evaluation of the ionic parameters of thronghfall revealed that the concentrations of most major ions were nonnormally distributed. Differences in the distributions of concentrations were found to occur between ions as well as between storms. Significant departures from normality were mainly due to right-skewness. Only H⁺ exhibited a left skewed sample distribution. None of the basic transformations were effective in normalizing all parameters. A high degree of spatial variability was observed for each of the chemical parameters. Nitrate and hydrogen ions (NO⁻₃ and H⁺), were found to be the least variable, whereas vegetatively mobile ions such as K⁺ and Mg²⁺ exhibited the greatest variability. Because of high event-to-event variation in the distributions of ion concentrations, specific sample-size requirements should be estimated for each ion through preliminary sampling of thronghfall precipitation from several storms. Contribution from the Pennsylvania State Univ. Agric. Exp. Stn. Journal Series no. 7879.
The peaking phenomenon in the presence of feature-selection

For a fixed sample size, a common phenomenon is that the error of a designed classifier decreases and then increases as the number of features grows. This peaking phenomenon has been recognized for forty years and depends on the classification rule and feature-label distribution. Historically, the peaking phenomenon has been treated by assuming a fixed ordering of the features, usually beginning with the strongest individual feature and proceeding with features of decreasing individual classification capability. This does not take into account feature-selection, which is commonplace in high-dimensional and small sample settings. This paper revisits the peaking phenomenon in the presence of feature-selection. Using massive simulation in a high-performance computing environment, the paper considers various combinations of feature-label models, feature-selection algorithms, and classifier models to produce a large library of error versus feature size curves. Owing to the prevalence of feature-selection in genomic classification, we also consider gene-expression-based classification of breast-cancer patient prognosis. Results vary widely and are strongly dependent on the combination. The error curves tend to fall into three categories: peaking, settling into a plateau, or falling very slowly over a long range of feature set sizes. It can be concluded that one should be wary of applying peaking results found in the absence of feature-selection to settings in which feature-selection is employed.
Nanodielectric surface flashover studies under kHZ range pulsed fields in partial vacuum

In this paper, we present the experimental results of surface flashover characteristics of nanodielectric filled epoxy resin in partial pressure of nitrogen. Nano-sized Al 2 O 3 and TiO 2 powder are used as fillers in epoxy resin with known properties. The surface flashover studies are conducted first under dc applied field and then 20 kHz pulsed unipolar field. The voltage, current, and light emission waveforms during the flashover events are recorded. The optical data is also collected by a video camera. All of the samples are produced in-house and for each sample, two weight ratios, namely 1:50, 1:16.6 (2% and 6%) (powder/epoxy), are cast on Teflon plates. Copper electrodes are mounted over the surface of dielectric samples to initiate surface flashover. The results of surface flashover voltages as a function of pressure are presented. Additionally, optical emission characteristics along with the voltage and current waveform data are also presented.
The Design and Implementation of a Low-Overhead Supply-Gated SRAM

The paper reports a virtual supply domain control technique for low-leakage SRAMs. This method encompasses cell-based sleep circuit tiling, sequentially regulated power-on/off, and flexible domain interfacing. The usual overhead associated with driving sleep transistors is significantly reduced by powering on/off gradually. Over 260times and 3times leakage reduction is observed in 65nm-technology hardware for hard and soft gating, respectively, including the leakage of control and drive circuits. Measured virtual domain power-on latency is compatible with high-frequency designs
In Vitro Fracture Behavior of Ceramic and Metal-Ceramic Restorations

Purpose Failed crowns and failure load data were studied to gain insights into the fracture behavior of prostheses under incisal-directed, load-to-failure testing. Materials and Methods Incisor crowns (n = 68) were fabricated: two all-ceramic groups (feldspathic veneer on high-strength core), differing in core design, and two metal-ceramic groups, differing in metal oxidation time (30 seconds v 3 minutes). Crowns were loaded to failure on their incisal edge. Gross visual, microscopic, and elemental microprobe analyses of failed crowns were coupled with Weibull analysis of the failure load data. Results Failure loads were higher for the normal oxidation time (TN) than for the extended oxidation time (TE) metal-ceramic crowns (P < .02), but both groups had indistinguishable Weibull moduli indicating the possibility of a common failure origin. Fracture behavior and Weibull results both implicated the oxide layer as being the origin of failure. The ratio of fracture loads (TE/TN) corresponded well with calculated oxide-volume ratios. Failure loads were lower for the all-ceramic than for the metal-ceramic crowns (P < .001). Fifty percent of the all-ceramic crowns failed by delamination of veneering glass alone, leaving a thin layer of residual glass on the core surface. Scanning electron microscope views showed that delamination occurred 10 to 50 μm away from the core-veneer interface. Electron microprobe elemental analysis of the core-veneer interface showed that residual core infiltration glass was not present on the core surface and that chemical alterations in the veneering glass were apparently limited to less than a 2- to 3-μm thick layer. Conclusions Failure for both restorative systems involved interfacial stresses with crack propagation occurring at or near the core-veneer interface. The weaker interface in the metal-ceramic system probably resulted from an increase in surface oxide volume, irrespective of any change in its adherence or physical properties. For the ceramic crowns, delamination crack fronts appeared to propagate through chemically unaltered veneering porcelain. Both the Weibull moduli and characteristic strengths were indistinguishable between either of the two ceramic core designs or between groups failing from delamination with or without core cracking/failure. This is consistent with delamination being the primary fracture process during failure. Clinical implications should not be drawn from results of this study because no correlation is known to have ever been established between clinical behavior and incisal load-to-failure results.
Intergenerational Visiting Patterns: Variation in Boundary Maintenance as an Explanation

SOCIOLOGISTS can now quite fairly be said to have recognized the importance of kinship in a modern industrial society. Beginning with Sussman's study of intergenerational helping patterns in the middle class (22), an increasing number of investigators have documented the importance of kindred to the city dweller's existence. These findings are contrary to the Simmel-Wirth picture of the urbanite as an isolated individual cut off from extended family contacts (19, 24). The trend in the literature is now so firmly against this thesis that a scholarly textbook in the area of family sociology has recently appeared in which the theoretical focus is on intergenerational ties (8). The present article is in the same vein. The first section is devoted to developing a theoretical rationale concerning factors influencing frequency of kinship contacts based on the phenomenon of boundary setting and maintenance that characterizes primary groups. The second section concerns an examination of hypotheses derived from the rationale using data from a sample of three generation lineages.
The earliest thymic progenitors for T cells possess myeloid lineage potential

There exists controversy over the nature of haematopoietic progenitors of T cells. Most T cells develop in the thymus, but the lineage potential of thymus-colonizing progenitors is unknown. One approach to resolving this question is to determine the lineage potentials of the earliest thymic progenitors (ETPs). Previous work has shown that ETPs possess T and natural killer lymphoid potentials, and rare subsets of ETPs also possess B lymphoid potential, suggesting an origin from lymphoid-restricted progenitor cells. However, whether ETPs also possess myeloid potential is unknown. Here we show that nearly all ETPs in adult mice possess both T and myeloid potential in clonal assays. The existence of progenitors possessing T and myeloid potential within the thymus is incompatible with the current dominant model of haematopoiesis, in which T cells are proposed to arise from lymphoid-. Our results indicate that alternative models for lineage commitment during haematopoiesis must be considered.
Fetal magnetic resonance imaging: jumping from 1.5 to 3 tesla (preliminary experience)

Several attempts have been made at imaging the fetus at 3 T as part of the continuous search for increased image signal and better anatomical delineation of the developing fetus. Until very recently, imaging of the fetus at 3 T has been disappointing, with numerous artifacts impeding image analysis. Better magnets and coils and improved technology now allow imaging of the fetus at greater magnetic strength, some hurdles in the shape of imaging artifacts notwithstanding. In this paper we present the preliminary experience of evaluating the developing fetus at 3 T and discuss several artifacts encountered and techniques to decrease them, as well as safety concerns associated with scanning the fetus at higher magnetic strength.
Carbon stocks on forestland of the United States, with emphasis on USDA Forest Service ownership

The U.S. Department of Agriculture Forest Service (USFS) manages one-fifth of the area of forestland in the United States. The Forest Service Roadmap for responding to climate change identified assessing and managing carbon stocks and change as a major element of its plan. This study presents methods and results of estimating current forest carbon stocks and change in the United States for public and private owners, consistent with the official 2010 U.S. greenhouse gas inventory, but with improved data sources for three states. Results are presented by National Forest System region, a major organizational management unit within the Forest Service, and by individual national forest. USFS forestland in the United States is estimated to contain an average of 192 Mg C/ha (mega grams carbon per hectare) on 60.4 million ha, for a total of 1 1,604 Tg C (teragrams C) in the year 2005. Privately-owned forestland averages 150 Mg C/ha on 173.8 million ha, with forestland of other public owners averaging 169 Mg C/ha on 43.1 million ha. In terms of change, private and USFS ownerships each sequester about a net 150 Tg C O2/yr, but an additional 92 Tg C O2/yr is stored in products from private harvests compared to about 3 Tg C O2/yr from harvest on USFS land. Emissions from other disturbances such as fires, as well as corresponding area estimates of disturbance are also important, but the needed datasets are not yet available. Recommendations are given for improving the estimates.
Fault Detection in Distributed Climate Sensor Networks Using Dynamic Bayesian Networks

The Atmospheric Radiation Measurement (ARM) program operated by the U.S. Department of Energy is one of the largest climate research programs dedicated to the collection of long-term continuous measurements of cloud properties and other key components of the earth’s climate system. Given the critical role that collected ARM data plays in the analysis of atmospheric processes and conditions and in the enhancement and evaluation of global climate models, the production and distribution of high-quality data is one of ARM’s primary mission objectives. Fault detection in ARM’s distributed sensor network is one critical ingredient towards maintaining high quality and useful data. We are modeling ARM’s distributed sensor network as a dynamic Bayesian network where key measurements are mapped to Bayesian network variables. We then define the conditional dependencies between variables by discovering highly correlated variable pairs from historical data. The resultant dynamic Bayesian network provides an automated approach to identifying whether certain sensors are malfunctioning or failing in the distributed sensor network. A potential fault or failure is detected when an observed measurement is not consistent with its expected measurement and the observed measurements of other related sensors in the Bayesian network. We present some of our experiences and promising results with the fault detection dynamic Bayesian network.
Closed-Form Analytical Results for the Rejection of Narrow-Band Interference in PN Spread-Spectrum Systems--Part II: Linear Interpolation Filters

The performance of PN spread-spectrum communication systems in the presence of narrow-band interference is studied when linear interpolation filters are employed for the estimation and subsequent suppression of the interference. Closed-form analytical expressions for the system's performance are established for a broad class of interference processes. The advantages of linear interpolation filters over predictive filters with identical number of taps are examined analytically and some unexpected results are obtained. The analytical results are illustrated by examples.
Simulations of Polarimetric Radar Signatures of a Supercell Storm Using a Two-Moment Bulk Microphysics Scheme

A new general polarimetric radar simulator for nonhydrostatic numerical weather prediction (NWP) models has been developed based on rigorous scattering calculations using the T-matrix method for reflectivity, differential reflectivity, specific differential phase, and copolar cross-correlation coefficient. A continuous melting process accounts for the entire spectrum of varying density and dielectric constants. This simulator is able to simulate polarimetric radar measurements at weather radar frequency bands and can take as input the prognostic variables of high-resolution NWP model simulations using one-, two-, and threemoment microphysics schemes. The simulator was applied at 10.7-cm wavelength to a model-simulated supercell storm using a double-moment (two moment) bulk microphysics scheme to examine its ability to simulate polarimetric signatures reported in observational studies. The simulated fields exhibited realistic polarimetric signatures that include ZDR and KDP columns, ZDR arc, midlevel ZDR and rhy rings, hail signature, and KDP foot in terms of their general location, shape, and strength. The authors compared the simulation with one employing a single-moment (SM) microphysics scheme and found that certain signatures, such as ZDR arc, midlevel ZDR, and rhy rings, cannot be reproduced with the latter. It is believed to be primarily caused by the limitation of the SM scheme in simulating the shift of the particle size distribution toward larger/smaller diameters, independent of mixing ratio. These results suggest that two- or higher-moment microphysics schemes should be used to adequately describe certain important microphysical processes. They also demonstrate the utility of a well-designed radar simulator for validating numerical models. In addition, the simulator can also serve as a training tool for forecasters to recognize polarimetric signatures that can be reproduced by advanced NWP models.
Bringing Out Head Start Talents: Findings From the Field

The purpose of this project was to address the need for identifying and providing programming for potentially gifted Head Start children. Four hundred forty-six Head Start children, 32 teachers, an...
The relationship of post-fire white ash cover to surface fuel consumption

White ash results from the complete combustion of surface fuels, making it a logically simple retrospective indicator of surface fuel consumption. However, the strength of this relationship has been neither tested nor adequately demonstrated with field measurements. We measured surface fuel loads and cover fractions of white ash and four other surface materials (green vegetation, brown non-photosynthetic vegetation, black char and mineral soil) immediately before and after eight prescribed fires in four disparate fuelbed types: boreal forest floor, mixed conifer woody slash, mixed conifer understorey and longleaf pine understorey. We hypothesised that increased white ash cover should correlate significantly to surface fuel consumption. To test this hypothesis, we correlated field measures of surface fuel consumption with field measures of surface cover change. Across all four fuelbed types, we found increased white ash cover to be the only measure of surface cover change that correlated significantly to surface fuel consumption, supporting our hypothesis. We conclude that white ash load calculated from immediate post-fire measurements of white ash cover, depth and density may provide an even more accurate proxy for surface fuel consumption, and furthermore a more physically based indicator of fire severity that could be incorporated into rapid response, retrospective wildfire assessments.
Ionized serum calcium levels following combined treatment for cancer of the head and neck

Thyroid function may be reduced after treatment of cancer of the head and neck, and hypothyroidism is much more common after combination therapy. Whether hypoparathyroidism and subsequent hypocalcemia also occur after such treatment is unknown. Few related studies have been published in which changes in total serum calcium have been studied after cancer treatment with radioactive iodine or external radiation. Twenty-two disease-free head and neck cancer patients were studied, 1 to 3 years after multimodal treatment, to determine if changes in serum ionized calcium levels or thyroid function were present. Our results suggest that parathyroid function, as represented by ionized calcium levels remains normal after multimodality (surgery, radiation and/or chemotherapy) combined treatment.
Cross-lagged panel correlation: A test for spuriousness.

Cross-lagged panel correlation is a method for testing spuriousness by comparing cross-lagged correlations. True experiments control for spuriousness by random assignment, but random assignment limits true experimental studies to independent variables that can be manipulated. Like any statistical method, cross-lagged analysis is based on a set of assumptions: synchronicity and stationarity. Different forms of stationarity have different consequences for both the changes in the synchronous correlations over time and the difference between cross-lags. Homogeneous stability is a necessary assumption in the identification of both the source and direction of a causal effect. Cross-lagged analysis is a low-power test. It is better adapted than either multiple regression or factor analysis for many questions in panel studies. Multiple regression must assume no errors of measurement in the independent variables and no correlated errors, while factor analysis must specify a particular factor structure. Two extended examples of cross-lagged analysis are discussed with special emphasis placed on the issue of stationarity and the estimation of reliability ratios.
Micromachined varactor with wide tuning range

A micromachined variable capacitor that achieves a wide tuning range is proposed. The device, which was fabricated in a polysilicon surface micromachining process, has a tuning range of 25% and a quality factor of 9.6 at 1 GHz when the capacitance is tuned to 4 pF.
Robust properties of solutions to linear-quadratic estimation and control problems

In this note we demonstrate a minimax robustness property for linear-quadratic estimation and control problems and discuss the importance of this result as well as the relevance of the general philosophy of robust design in estimation and control.
Carbon-14 terrestrial ages of Antarctic meteorites

The carbon-14 terrestrial ages of four Yamato meteorites are measured and compared with the C-14 terrestrial ages of eighteen meteorites from Victoria Land. The youngest Yamato meteorite, Y-75102, is 4300 + or - 1000 yr; the oldest, Y-74459, is 24,000 + or - 2000 yr. The Yamato meteorite site is collecting recent falls, less than 25,000 yr, at a more rapid rate than the Victoria Land sites.
The Acquisition of Morphology by a Bilingual Child: A Whole-Word Approach.

ADDRESS FOR CORRESPONDENCEMarilyn May Vihman, Department of Linguistics, Stanford University, Stanford, CA 94305ABSTRACTThe avoidance of inflectional markers, a kind of "macrodevelopment'' in the acquisition of morphol-ogy, is described in this analysis bf the strategies displayed by a bilingual child simultaneouslyexposed to Estonian and to English. A whole-word approach was manifested in: the acquisition ofpostpositions before case endings; the learning of pronominal case and other suppletive or irregularforms before regular markers were used; the borrowing of the analytic English construction with haveinto Estonian; and the preference for did + verb for the expression of the English past tense. Ininterpreting these data the factor of bilingualism per se is weighed against the possible existence of awhole-word approach to language in general as a manifestation of a particular cognitive style.
A possible role for lutein and zeaxanthin in cognitive function in the elderly

Epidemiologic studies suggest that dietary lutein and zeaxanthin may be of benefit in maintaining cognitive health. Among the carotenoids, lutein and zeaxanthin are the only two that cross the blood-retina barrier to form macular pigment (MP) in the eye. They also preferentially accumulate in the human brain. Lutein and zeaxanthin in macula from nonhuman primates were found to be significantly correlated with their concentrations in matched brain tissue. Therefore, MP can be used as a biomarker of lutein and zeaxanthin in primate brain tissue. This is of interest given that a significant correlation was found between MP density and global cognitive function in healthy older adults. An examination of a relation between cognition and lutein and zeaxanthin concentrations in the brain tissue of decedents from a population-based study in centenarians found that zeaxanthin concentrations in brain tissue were significantly related to antemortem measures of global cognitive function, memory retention, verbal fluency, and dementia severity after adjustment for age, sex, education, hypertension, and diabetes. In univariate analyses, lutein was related to recall and verbal fluency, but the strength of the associations was attenuated with adjustment for covariates. However, lutein concentrations in the brain were significantly lower in individuals with mild cognitive impairment than in those with normal cognitive function. Last, in a 4-mo, double-blinded, placebo-controlled trial in older women that involved lutein supplementation (12 mg/d), alone or in combination with DHA (800 mg/d), verbal fluency scores improved significantly in the DHA, lutein, and combined-treatment groups. Memory scores and rate of learning improved significantly in the combined-treatment group, who also showed a trend toward more efficient learning. When all of these observations are taken into consideration, the idea that lutein and zeaxanthin can influence cognitive function in older adults warrants further study.
Uptake of radiolabeled glucose analogues by organotypic cerebellar cultures

Permeability of brain cells to radiolabeled glucose analogues with sucrose or inulin or L-glucose was studied in the living, intact state of the organotypic cerebellar cultures. In vitro uptake of 3H 3-O-methyl D-glucose and 3H 2-deoxy-D-glucose exhibited saturation kinetics with increasing substrate concentrations. Each of the labeled sugars uptake could be self-inhibited in the presence of unlabeled (cold) substrate and cross-inhibited with cold glucose or xylose or phlorizin present in the incubating medium. The uptake was Na-independent and stereo-specific for D-form.
Paromomycin in the treatment of amoebiasis in Nyasaland.

Abstract Fifty-three of 54 cases (98 per cent.) of chronic amoebiasis were treated successfully at dosage levels ranging from 4.7 mg./kg./day for 3 days, to 25 mg./kg./day for 5 days. The one failure was at the lowest level. The follow-up period was for 12 weeks. During the last few weeks of follow-up study, there were eight reinfections—or, less likely, relapses—from the highest to the lowest dosage ranges. No side-effects were observed.
A Semiempirical Microscale Model of the Surface Energy Balance and Its Application to Two Urban Rooftops

Abstract Individual structures within the same local-scale (102–104 m) environment may experience different microscale (<103 m) climates. Urban microclimate variations are often a result of site-specific features, including spatial and material characteristics of surfaces and surrounding structures. A semiempirical surface energy balance model is presented that incorporates radiative and meteorological measurements to statistically parameterize energy fluxes that are not measured directly, including sensible heat transport, storage heat flux through conduction, and evaporation (assumed to be negligible under dry conditions). Two Chicago rooftops were chosen for detailed study. The City Hall site was located in an intensely developed urban area characterized by close-set high-rise buildings. The University rooftop was in a highly developed area characterized by three- to seven-story buildings of stone, concrete, and brick construction. Two identical sets of instruments recorded measurements contemporaneous...