cssi/SciSciGPT-SciSciNet huggingface dataset:
Genetic divergence and migration patterns in a North American passerine bird: implications for evolution and conservation

Like many other migratory birds, the black-throated blue warbler (Dendroica caerulescens) shows pronounced differences in migratory behaviour and other traits between populations: birds in the southern part of the breeding range have darker plumage and migrate to the eastern Caribbean during the winter, whereas those in the north have lighter plumage and migrate to the western Caribbean. We examined the phylogeography of this species, using samples collected from northern and southern populations, to determine whether differentiation between these populations dates to the Pleistocene or earlier, or whether differences in plumage and migratory behaviour have arisen more recently. We analysed variation at 369 bp of the mitochondrial control region domain I and also at seven nuclear microsatellites. Analyses revealed considerable genetic variation, but the vast majority of this variation was found within rather than between populations, and there was little differentiation between northern and southern populations. Phylogeographic analyses revealed a very shallow phylogenetic tree, a star-like haplotype network, and a unimodal mismatch distribution, all indicative of a recent range expansion from a single refugium. Coalescent modelling approaches also indicated a recent common ancestor for the entire group of birds analysed, no split between northern and southern populations, and high levels of gene flow. These results show that Pleistocene or earlier events have played little role in creating differences between northern and southern populations, suggesting that migratory and other differences between populations have arisen very recently. The implications of these results for the evolution of migration and defining taxonomic groups for conservation efforts are discussed.
THE POLLS—A REVIEW: THE 1993 RUSSIAN ELECTION POLLS

In the last 5 years there have been three instances in which major efforts by pollsters have failed in predicting the outcome of national elections-in Nicaragua in 1989, in Britain in 1992, and in Russia in 1993. These failures, however, offer an excellent opportunity to examine the factors that undermine our ability to predict various social events, especially election results. The debates surrounding these three cases involved general issues, including the quality of the methodology, the political environment during the election campaign, and the political neutrality of the pollsters. Earlier Poll Reviews have addressed the Nicaraguan and British cases (see Jowell et al. 1993; Miller 1991). In this review I will attempt to add to this body of knowledge by addressing the Russian case, specifically examining both the commonalities and differences among the three cases. The comparison between Nicaragua and Russia-both countries with authoritative political systems in their recent pasts-is particularly instructive.
Contrasting the roles of learning in butterflies foraging for nectar and oviposition sites

Abstract We successfully trained adult Edith's checkerspot butterflies, Euphydryas editha, to modify their alighting preference for a novel flower and to reduce their handling time when searching for nectar in a flower that was difficult for them to use. Butterflies caught feeding from the difficult flower (manzanita, Arctostaphylos spp., Ericaceae) in the field were able to find its nectar more quickly than butterflies caught feeding from a simpler flower (pussypaw,Calyptridium umbellatum , Portulacaceae), providing evidence that these learning abilities contribute to natural foraging behaviour. The strong role of learning in nectar foraging contrasts with results of prior experiments that failed to show any role of learning in oviposition behaviour by butterflies in the same population that we studied. These butterflies had failed both to improve their finding of host plants with experience and to change their host preferences as a result of exposure to different hosts. Euphydryas editha can learn to prefer and use particular nectar species, but do not learn to prefer or find plants for oviposition. Comparison between oviposition and host feeding is consistent with theoretical predictions that learning should be more pronounced with respect to behaviours whose performance provides information about effects on fitness, or where each of many performances has a small effect on fitness. It is not consistent with the hypothesis that learning may occur in some behaviours because it is necessary in other contexts.
Ramsey sets, the Ramsey ideal, and other classes over R

We improve results of Marczewski, Frankiewicz, Brown, and others comparing the ω-ideals of measure zero, meager, Marczewski measure zero, and completely Ramsey null sets; in particular, we remove CH from the hypothesis of many of Brown's constructions of sets lying in some of these ideals but not in others. We improve upon work of Marczewski by constructing, without CH, a nonmeasurable Marczewski measure zero set lacking the property of Baire. We extend our analysis of ω-ideals to include the completely Ramsey null sets relative to a Ramsey ultrafilter and obtain all 32 possible examples of sets in some ideals and not others, some under the assumption of MA, but most in ZFC alone. We also improve upon the known constructions of a Marczewski measure zero set which is not Ramsey by using a set theoretic hypothesis which is weaker than those used by other authors. We give several consistency proofs: one concerning the relative sizes of the covering numbers for the meager sets and the completely Ramsey null sets; another concerning the size of non; and a third concerning the size of add. We also study those classes of perfect sets which are bases for the class of always first category sets.
Using the cockpit display to improve on-aircraft maintenance

When a cockpit display is squawked by the pilot due to an observed problem, the normal maintenance action that follows is to replace the display. It is often found that the replaced display shows the same problem and the source of the problem is elsewhere in the system. This paper discusses a unique feature as part of the display architecture currently used by Astronautics, which uses the display to indicate to the maintenance technician, while on the aircraft, if there is a system problem. This greatly reduces maintenance times due to unnecessary display replacements.
Connecting with others in the midst of stressful upheaval on September 11, 2001

Abstract This study was originally planned from September tenth through twelfth to assess concurrent use of three real-time data sources during a usual day. When the World Trade Center towers collapsed, the plan expanded to describe 24-hour blood pressure and heart rate, natural environment word use, television viewing/radio listening, and self-reported diary feelings for six undergraduate students in the midst of stressful upheaval. Heart rate, “we” word-use and television viewing/radio listening increased over time. Higher negative and lower positive feelings/emotions occurred during morning hours on September 11. Students connected with others and shared good thoughts. Measurement with real-time data sources was informative.
Mechanisms of peptide amphiphile internalization by SJSA-1 cells in vitro.

Self-assembly of peptide amphiphiles into nanostructures makes them attractive for a variety of applications in drug and peptide delivery. We here report on the interactions of micelles composed of a palmitoylated, pro-apoptotic peptide derived from p53 tumor suppressor protein with a human cancer cell line. Characterization of self-assembly in aqueous buffered solutions revealed formation of elongated rod-like micelles above a critical micelle concentration. Our results however demonstrate that monomers instead of micelles are internalized, a finding that correlates with the dynamic nature of the assemblies and the noncovalent interactions that hold them together. Internalization is shown to occur via adsorption-mediated, energy-dependent pathways, resulting in accumulation of the material in endocytic vesicles. We conclude that palmitoylation of peptides is an efficient way to increase peptide permeability inside SJSA-1 cells and that increased micelle stability would be required for intact micelle inte...
Sequential transition patterns of preschoolers’ social interactions during child-initiated play: Is parallel-aware play a bidirectional bridge to other play states?☆

Abstract Lag-sequential analysis was used to explore the simultaneous sequential transition patterns of preschoolers’ social play within natural classroom settings. Subjects were 167 middle- and lower-income 4-year-olds (90 boys and 77 girls) videotaped in three child-initiated play centers. Results indicated that the proportion of social-play states did not vary during the play episodes even when accounting for type of activity center, gender, and SES. Findings also revealed that, during and within child-initiated play centers, a reciprocal relationship existed between parallel-aware and other social-play states. Specifically, knowing preschoolers who were in parallel-aware play significantly increased the likelihood of predicting their shifts into cooperative-social and onlooker play; while knowing children were in cooperative-social, onlooker, and solitary-constructive play predicted shifts into parallel-aware play. Likewise, similar to school-age children’s group-entry patterns, preschoolers exhibited a three-step sequential play pattern of going from onlooker behavior into parallel-aware play then into cooperative-social play during child-initiated activities. Also supported was the notion that during child-initiated play episodes parallel-aware play is more than a static bridge into cooperative-social play; it is a dynamic bidirectional crossroad between other social-play states.
MEMS based wireless energy harvesting mechanism for ECG and BCG application

The paper presents the novel concept of a low frequency, wireless energy harvesting system capable of acquiring, processing, and transmitting electrocardiogram (ECG) and Ballistocardiogram (BCG) data. The System on Chip (SoC) is designed to be capable of autonomous power management and operation derived from harvested power. A MEMS based piezoelectric energy harvesting cantilever is employed for this purpose. It consists of a silicon beam integrated with piezoelectric thin film (PZT) elements fabricated on parallel top. A silicon proof mass is attached to the silicon beam. The arrangement of silicon beam and proof mass enables the structure to extract energy from low frequency vibrations. The energy harvester when integrated with the proposed system can perform ECG heart rate extraction and atrial fibrillation detection while only consuming a few μWs of harvested power. This novel design of energy harvesters provides an additional benefit of Ballistocardiogram (BCG) that can help in early stages of a heart disease diagnostics.
A causal model of burnout among self-managed work team members.

Abstract The findings on burnout that are almost universally from research in service settings are applied to an industrial setting with self-managed work teams. Researchers formulated several hypotheses on the basis of this literature. These hypotheses were then used to develop a structural (causal) model that was tested and refined using LISREL 8. Data were collected from 320 employees concerning perceptions of several job and organization conditions, as well as the three components of burnout. Results indicated that role conflict contributed to emotional exhaustion, and participation in work teams diminished it. Job ambiguity, low co-worker support, and low job ability contributed to feelings of low personal accomplishment. These results were consistent with previous findings. When insufficient time to complete a job was removed from the workload measures, workload actually diminished burnout, a finding opposite from previous research. Other organization factors had no significant impact on burnout in ...
Nitrate contamination in private wells in rural Alabama, United States

Abstract Nitrate–N (NO3−–N) concentrations in random water samples from rural residential wells in Alabama, USA, were analyzed over an 8-year period from 1992 to 1999. Data collected included land use, well depth, septic tank use and distance from the well and also livestock and cropping activities around wells. Of 1021 available data sets, 36% of samples showed nitrate–N concentration of higher than 1.0 mg/l, indicating the possible influence of anthropogenic activities. About 1.7% of samples had a nitrate–N concentration of higher than 10 mg/l. Results indicate nitrate contamination in groundwater was relatively low and stable in Alabama. Logistic regression analysis indicated that well depth, pH, and cropping activity were factors of statistical significance in influencing nitrate–N concentration in these wells. Factors such as septic tank use and livestock activities did not show a close link to nitrate–N concentration in wells tested.
The presence of T-lymphocyte subpopulations (CD4 and CD8) in pterygia: evaluation of the inflammatory response.

Introduction The aim of our study was to confirm the presence of inflammatory T-lymphocyte subpopulations (CD4 and CD8) in pterygium specimens with regards to clinical severity. Additionally, we examined the effect of topical anti-inflammatory agents on the presence of T-lymphocyte subpopulations.
Atomic Force Microscope: Implementations

Our version of the atomic force microscope (AFM), and variants which measure electric and magnetic force are described from an engineering viewpoint. Discussion centers on design and performance issues, with emphasis on application to magnetic recording. The basic force probe consists of an L-shaped wire cantilever, whose end is etched to a radius of less than 1000 A, mounted on a piezoelectric bimorph When the tip is held close to a sample, forces between tip and sample modify the dynamical properties of the resonant cantilever; the force gradient changes the effective spring constant, and thus the resonant frequency. Vibration of the tip is measured by heterodyne interferometry, a technique about as sensitive as tunnelling but easier to set up and insensitive to slow drifts. By driving the tip near resonance, the change in the resonance frequency is translated into an amplitude shift; force gradients of 10-4N/m and force increments of 10-13N have been measured in this way. This atomic force probe has achieved lateral resolutions of 50 A, and there seems to be no fundamental impediment to achieving atomic resolution. The magnetic force microscope (MFM) is very similar. It uses a steel wire tip to measure magnetic field or field gradient with a spatial resolution of better than 1000 A. Data are shown, which demonstrate the usefulness of magnetic imaging for profiling the field patterns in recording heads and disk media.© (1988) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Analysis and Correction of Errors Generated by Slowly Moving Shocks

In problems where shock waves move slowly relative to the grid, numerical errors in density and momentum may occur at the shock and propagate downstream, thereby contaminating the solution. These errors are analyzed in the present work and a fix is proposed. The errors are divided into two classes: start-up errors and post-shock oscillations. It is shown that a traveling wave analysis of the isothermal Euler equations describes the spike formation in the momentum for the first-order accurate Lax-Friedrichs solver very well. By smearing the density and momentum profiles appropriately, the corresponding downstream-propagating wave can be removed. The post-shock oscillations have been characterized; as a fix for this problem, a lower bound on the wave speed of the first-order accurate HLL solver is set in the artificial viscosity coefficient for density in the continuity equation. The implementation to higher-order accurate methods is not straightforward; an additional fix is proposed, which is performs well on the full multi-dimensional Euler equations.
Electromagnetic induction by ocean currents: BEMPEX

Abstract The theory of electromagnetic induction by ocean water currents is reviewed using a modal formulation, with an emphasis on interactions of the induced fields with the conducting Earth and on their association with distinct, dynamically significant parts of the water velocity field. It is shown that the dominant electromagnetic mode at low frequencies ( A recent, major experiment to study the low-frequency variability of the ocean using electromagnetic induction principles is described. Denoted by the acronym BEMPEX for Barotropic ElectroMagnetic and Pressure EXperiment, this effort involves 41 seafloor magnetometers, horizontal and vertical electrometers, and pressure recorders covering an area 1100 km east-west by 1000 km north-south in the North Pacific for 11 months. The major oceanographic objectives of BEMPEX are multifold, and include a description of the wind-forced barotropic variability of the deep ocean, studies of the frequency-wavenumber characteristics of certain oscillations of basin-wide scale, and tests of predictions from existing models of wind-forcing.
Multiple Expectational Equilibria Under Monopolistic Competition

This paper shows that a monopolistically competitive economy with real investment can have multiple rational expectations equilibria: one is associated with entrepreneurs' optimistic expectations about future demand; another with entrepreneurs' pessimism. It also shows that an optimistic expectational equilibrium Pareto dominates a pessimistic equilibrium. An investment subsidy can be beneficial both by reducing the original underinvestment distortion and by changing firms' expectations from pessimistic to optimistic. The most important assumption is increasing returns to scale, and monopolistic competition makes increasing returns consistent with each producer's optimization.
Denitrifying Bacteria from the Genus Rhodanobacter Dominate Bacterial Communities in the Highly Contaminated Subsurface of a Nuclear Legacy Waste Site

The effect of long-term mixed-waste contamination, particularly uranium and nitrate, on the microbial community in the terrestrial subsurface was investigated at the field scale at the Oak Ridge Integrated Field Research Challenge (ORIFRC) site in Oak Ridge, TN. The abundance, community composition, and distribution of groundwater microorganisms were examined across the site during two seasonal sampling events. At representative locations, subsurface sediment was also examined from two boreholes, one sampled from the most heavily contaminated area of the site and another from an area with low contamination. A suite of DNA- and RNA-based molecular tools were employed for community characterization, including quantitative PCR of rRNA and nitrite reductase genes, community composition fingerprinting analysis, and high-throughput pyrotag sequencing of rRNA genes. The results demonstrate that pH is a major driver of the subsurface microbial community structure and that denitrifying bacteria from the genus Rhodanobacter (class Gammaproteobacteria) dominate at low pH. The relative abundance of bacteria from this genus was positively correlated with lower-pH conditions, and these bacteria were abundant and active in the most highly contaminated areas. Other factors, such as the concentration of nitrogen species, oxygen level, and sampling season, did not appear to strongly influence the distribution of Rhodanobacter bacteria. The results indicate that these organisms are acid-tolerant denitrifiers, well suited to the acidic, nitrate-rich subsurface conditions, and pH is confirmed as a dominant driver of bacterial community structure in this contaminated subsurface environment.
An improved method for renal allograft biopsy

Biopsy of the renal allograft provides useful information both for the management of the transplant recipient and for research in the study of the histopathology of rejection and recurrence of disease in renal allografts. Several techniques have been published for doing percutaneous needle biopsy of the renal allograft [1—3]. This procedure, however, is still viewed with apprehension by many physicians working in the transplant field. Open surgical biopsy, instead, is being done at some centers [4—5]. We describe a technique for obtaining percutaneous biopsies which is simple and safe. It differs from previously described techniques in approach, utilizing metal clips around the kidney for selection of the biopsy site under fluoroscopy without need for infusion of intravenous pyelography (IVP) contrast material.
Geophysical features influence the climate change sensitivity of northern Wisconsin pine and oak forests

Landscape-scale vulnerability assessment from multiple sources, including paleoecological site histories, can inform climate change adaptation. We used an array of lake sediment pollen and charcoal records to determine how soils and landscape factors influenced the variability of forest composition change over the past 2000 years. The forests in this study are located in northwestern Wisconsin on a sandy glacial outwash plain. Soils and local climate vary across the study area. We used the Natural Resource Conservation Service's Soil Survey Geographic soil database and published fire histories to characterize differences in soils and fire history around each lake site. Individual site histories differed in two metrics of past vegetation dynamics: the extent to which white pine (Pinus strobus) increased during the Little Ice Age (LIA) climate period and the volatility in the rate of change between samples at 50-120 yr intervals. Greater increases of white pine during the LIA occurred on sites with less sandy soils (R² = 0.45, P < 0.0163) and on sites with relatively warmer and drier local climate (R² = 0.55, P < 0.0056). Volatility in the rate of change between samples was positively associated with LIA fire frequency (R² = 0.41, P < 0.0256). Over multi-decadal to centennial timescales, forest compositional change and rate-of-change volatility were associated with higher fire frequency. Over longer (multi-centennial) time frames, forest composition change, especially increased white pine, shifted most in sites with more soil moisture. Our results show that responsiveness of forest composition to climate change was influenced by soils, local climate, and fire. The anticipated climatic changes in the next century will not produce the same community dynamics on the same soil types as in the past, but understanding past dynamics and relationships can help us assess how novel factors and combinations of factors in the future may influence various site types. Our results support climate change adaptation efforts to monitor and conserve the landscape's full range of geophysical features.
The terminal residues of aspergillopeptidase B.

The amino- and carboxyl-terminal residues of aspergillopeptidase B, the predominant alkaline proteinase of Aspergillus oryzae, have been determined. The enzyme has a single N-terminal glycine and a C-terminal alanine, and therefore it consists of a single polypeptide chain.
The dynamic behavior and stress relaxation of polymer melts

Polymer melts exhibit a decrease in apparent viscosity as a function of decreasing time scale of shearing. In order to obtain an understanding of the mechanisms giving rise to this non-Newtonian behavior studies have been made of the dynamic linear viscoelastic response, the limit of linear viscoelastic behavior and the stress relaxation in polymer melts after steady state shearing. The results of these experiments are analyzed with respect to shear induced changes in the relaxation spectrum and the effect of these changes on the apparent viscosity.
Sulfide and sulfate saturation in hydrous silicate melts

A series of hydrothermal experiments was performed over a wide range of pressures, temperatures, oxygen fugacities, and melt FeO content, in order to examine the effects of physical changes on sulfur solubility in fractionated hydrous silicate melts. On the basis of the experimental results, it is concluded that upper crustal oxidation-reduction reactions and crystal fractionation processes may exert considerable influence on the amount of sulfur contained in magmas erupted at the surface. The application of the experimental results to investigations of volatile transport and volcanic degassing processes on the earth, Venus, and Mars is discussed
Human Perception of the Maximum Safe Speed of Robot Motions

A laboratory experiment was conducted to determine the maximum speeds of robot arm motion considered by the subjects as safe for human operators working in a close proximity of the robot's working envelope. Twenty-nine college students (16 males and 13 females) participated in the study as monitors of the simulated assembly tasks performed by two industrial robots of different size and work capabilities. The results show that the speed selection process depends on the robot's physical size and its initial speed at the start of the adjustment process. Subjects selected higher speeds as “safe” if they were first exposed to the maximum speed of the robot, and significantly lower values when the initial speed of the robot's actions was only 5% of maximum. It was also shown that the subject's previous exposure to robots and the level of their knowledge of industrial robots highly affected their perception of safe speeds of robot motions. Such effects differ, however, between males and females.
Effect of gamma radiation on levels of α-tocopherol in red meats and turkey.

Abstract The effect of low dose ionizing radiation on free α-tocopherol levels in beef, pork and lamb longissimus dorsi muscle and on turkey leg and breast muscle were determined. The samples were irradiated in air with a 137Cs source at eight dose levels between 0 and 9.4 kGy at 5 °C. Irradiation resulted in a significant decrease in α-tocopherol levels in all of the meats studied. There were no statistically significant differences in the rate of loss of tocopherol due to species, with the exception of turkey breast. The rate of loss of tocopherol in turkey breast tissue was greater than the other meats. The information obtained in this study may be of use for ‘chemiclearance’ purposes since the relative effects due to species variation were examined.
On coding for delay - New approaches based on network coding in networks with large latency

In networks with large latency, feedback about received packets may lag considerably the transmission of the original packets, limiting the feedback's usefulness. Moreover, time duplex constraints may entail that receiving feedback may be costly. In this work, we consider tailoring feedback and coding jointly in such settings to reduce the expected delay for successful in order reception of packets. We find that, in certain applications, judicious choices provide results that are close to those that would be obtained with a full-duplex system.
Pilot Subjective Assessments During an Investigation of Separation Function Allocation Using a Human-In-The-Loop Simulation

Two human-in-the-loop simulation experiments were conducted to investigate allocation of separation assurance functions between ground and air and between humans and automation. The experiments modeled a mixed-operations concept in which aircraft receiving ground-based separation services shared the airspace with aircraft providing their own separation service (i.e., self-separation). The two experiments, one pilot-focused and the other controller-focused, addressed selected key issues of mixed operations and modeling an emergence of NextGen technologies and procedures. This paper focuses on the results of the subjective assessments of pilots collected during the pilot-focused human-in-the-loop simulation, specifically workload and situation awareness. Generally the results revealed that across all conditions, pilots' perceived workload was low to medium, with the highest reported levels of workload occurring when the pilots experienced a loss of separation during the scenario. Furthermore, the results from the workload data and situation awareness data were complimentary such that when pilots reported lower levels of workload they also experienced higher levels of situation awareness.
Instruction in Professional Issues Using a Cooperative Learning, Case Study Approach

This article describes a cooperative learning approach for instructing communication disorders students about professional issues. We developed case studies characteristic of the complex professional issues encountered in employment settings. We assigned students to cooperative learning groups to examine their assigned case study; collect and learn about policies and documents impacting professional practice; select, analyze, and synthesize materials to take an ethical and defensible position on the issue; and prepare and present their position orally and in writing. Evaluations of the approach indicated that students met the instructional objectives for the activity. This article presents implications and suggestions for future use of the approach.
Predictive coordination of multiple on-chip resources for chip multiprocessors

Efficient on-chip resource management is crucial for Chip Multiprocessors (CMP) to achieve high resource utilization and enforce system-level performance objectives. Existing multiple resource management schemes either focus on intra-core resources or inter-core resources, missing the opportunity for exploiting the interaction between these two level resources. Moreover, these resource management schemes either rely on trial runs or complex on-line machine learning model to search for the appropriate resource allocation, which makes resource management inefficient and expensive. To address these limitations, this paper presents a predictive yet cost effective mechanism for multiple resource management in CMP. It uses a set of hardware-efficient online profilers and an analytical performance model to predict the application's performance with different intra-core and/or inter-core resource allocations. Based on the predicted performance, the resource allocator identifies and enforces near optimum resource partitions for each epoch without any trial runs. The experimental results show that the proposed predictive resource management framework could improve the weighted speedup of the CMP system by an average of 11.6% compared with the equal partition scheme, and 9.3% compared with existing reactive resource management scheme.
Food allergy: manifestations, diagnosis and management.

Adverse reactions to food are common but only a fraction of them are due to hypersensitivity (or allergy). Of the latter, immunoglobulin (Ig)E-mediated reactions appear to be the most common and best understood. A wide variety of manifestations may affect various body systems, particularly the gastrointestinal tract, skin and respiratory tract. Diagnosis depends primarily on thorough medical history, often supplemented by skin testing or specific serum IgE antibody measurement. Verification would require appropriately designed challenge testing. At present, treatment is primarily strict avoidance of the offending food, together with crossreacting other foods. Several immunomodulatory therapeutic agents are being explored. A few studies demonstrated a potential benefit of probiotics for prophylaxis and treatment. A multicenter study is currently investigating the efficacy and safety of anti-IgE in subjects with peanut allergy. Experimental studies in mice revealed preliminary findings that promise vaccine ...
Design of High NA Imaging Systems by Control of Rays from On-Axis Object Point

We present numeric methods for designing an high NA axi-symmetric imaging optical system that is corrected for all orders of spherical aberrations, coma and aberrations with 2nd order field dependence.
Densely Granulated Murine NK Cells Eradicate Large Solid Tumors

NK cells inhibit early stages of tumor formation, recurrence and metastasis. Here we show that NK cells can also eradicate large solid tumors. Eradication depended on the massive infiltration of proliferating NK cells due to IL15 released and presented by the cancer cells in the tumor microenvironment. Infiltrating NK cells had the striking morphological feature of being densely loaded with PAS-positive, diastase-resistant granules, resembling uterine NK cells. Perforin-mediated killing by these densely granulated NK cells was essential for tumor eradication. Expression of the IL15 receptor α on cancer cells was needed to efficiently induce granulated NK cells and expression on host stromal cells was essential to prevent tumor relapse after near complete destruction. These results indicate that IL15 released at the cancer site induces highly activated NK cells that lead to eradication of large solid tumors.
Research Spotlight: Glacial dust carries iron to the Gulf of Alaska

[1] Iron is an essential nutrient for phytoplankton in the ocean, but how does iron get to the ocean? In the Gulf of Alaska the sources of iron and the processes that transport iron to the ocean are not well quantified. Crusius et al. combined satellite, meteorological, and other data to infer one source of “bioavailable” iron: dust from the Gulf of Alaska coastline. Glacial erosion causes large amounts of fine-grained sediment, known as glacial flour, to be deposited near the coast. Some of this material can be resuspended by the wind and transported hundreds of kilometers from shore during dust storm events that occur at least annually, and most often in the fall, when river levels are low and sediments are exposed. The authors found that glacial flour dust storms are a significant source of iron to the Gulf of Alaska. They estimated the amount of iron-containing dust transported to the Gulf of Alaska from the Copper River valley during one 2006 dust storm to be between 25 and 80 kilotons. (Geophysical Research Letters, doi:10.1029/2010GL046573, 2011)
Quantitative analysis for in situ sintering of 3% yttria-stablized zirconia in the transmission electron microscope

Studying particle-agglomerate systems compared to two-particle systems elucidates different stages of sintering by monitoring both pores and particles. We report on in situ sintering of 3% yttria-stablized zirconia particle agglomerates in the transmission electron microscope (TEM). Real-time TEM observations indicate neck formation and growth, particle coalescence and pore closure. A MATLAB-based image processing tool was developed to calculate the projected area of the agglomerate with and without internal pores during in situ sintering. We demonstrate the first densification curves generated from sequentially acquired TEM images. The in situ sintering onset temperature was then determined to be at 960 °C. Densification curves illustrated that the agglomerate projected area which excludes the internal observed pores also shrinks during in situ sintering. To overcome the common projection problem for TEM analyses, agglomerate mass-thickness maps were obtained from low energy-loss analysis combined with STEM imaging. The decrease in the projected area was directly related to the increase in mass-thickness of the agglomerate, likely caused by hidden pores existing in the direction of the beam. Access to shrinkage curves through in situ TEM analysis provides a new avenue to investigate fundamental mechanisms of sintering through directly correlating microstructural changes during consolidation with mesoscale densification behavior.
Dislocation core structures in B2 NiAl alloys

Abstract Single crystals of Ni-48Al, Ni-50Al and Ni-52Al have been deformed in the [101] orientation. Slip trace and diffraction contrast Burger's vector analyses have been used to characterize the deformation characteristics of these alloys. Ni-50Al was found to display predominantly 〈001〉{100} slip with some limited 〈001〉{100} slip while the non-stoichiometric Ni-48Al and Ni-52Al exhibited a predominance of 〈001〉{100} slip with limited 〈001〉{110} dislocation motion. Direct imaging of the 〈001〉{100} edge dislocation cores by high resolution electron microscopy revealed differences between Ni-50Al and Ni-48Al. Cores in the Ni-48Al were found to display significantly greater spreading of the cores, both within and normal to the slip plane, than for Ni-50Al. The mechanical behavior of these alloys is rationalized in terms of these observations. Comparison of the experimental core images with simulated images based on embedded atom models of the cores indicates that the models are able accurately to predict core structures in stoichiometric alloys, but may have some limitations in predicting structures in non-stoichiometric alloys.
A Microprocessor-Based Feedback System for Phase and Amplitude Stabilization of Superconducting Resonators

A microprocessor-based feedback system has been designed, built and tested to provide phase and amplitude stabilization of a 150 MHz superconducting splitring accelerating resonator for heavy ions. This system has a bandwidth of 400 kHz and can operate with positive feedback as a limiter or with negative feedback locking to an external reference. Direct negative feedback has already been used to stabilize the phase of a split-loop resonator to an accuracy of 0.01 radian at 2 MV/m.1 All of the parameters of the system: gains, phase shifts, level reference, phase reference and frequency of the synthesizer are digitally controlled either manually or by the microprocessor. The advantages of this control system include automatic operation of the accelerator, pre-warning of an eventual breakdown of a resonator, and automatic recovery from such a breakdown.
Electrochemical assembly of metallopolymeric films via reduction of coordinated 5-chlorophenanthroline

Electrochemical reduction of iron, osmium, and ruthenium complexes containing the ligand 5-chlorophenanthroline leads to the controlled growth of metallopolymers as electrode coatings. The coatings are electroactive and display a reversible electrochromic effect upon metal oxidation. Auger electron spectroscopy studies show that the polymerization mechanism involves carbon-chlorine bond cleavage and the generation of exchangeable chloride ions. The proposed linkage mechanisms involve direct carbon-carbon coupling of phenanthroline ligands. The possible utility of these new polymers in redox conductivity studies and in microstructure fabrication is noted
π-Stacking as a Control Element in the (2-PhInd)2Zr Elastomeric Polypropylene Catalyst

The crystal structure of the Coates-Waymouth catalyst precursor, bis(2-phenylindenyl)zirconium dichloride ((2-PhInd)-ZrCl{sub 2}, 1) contained two distinct conformers in the unit cell. In one conformer the indenyl ligands were syn to one another (a meso stereochemistry), while in the other cnoformer the indenyl ligands were anti to one another (a rac stereochemistry). To understand why the catalyst formed from 1 produces blocks of isotactic and atactic polymer, a UFF force field conformational study on the catalyst precursor 1 and a model polymer system, (2-PhInd)Zr(CH{sub 3})(C{sub 7}H{sub 15}), was undertaken. A computational model is presented, which contains four main features. (1) The rac and meso conformations of the metallocene system observed by Coates and Waymouth are nearly isoenergetic (within 0.6 kcal/mol of each other). (2) The barrier between the rac and meso conformations is comparable to observed insertion barriers. (3) The shape of the rac conformation is consistent with the established stereochemical model of metallocene polymerizations. (4) Both the rac and meso conformations display {pi}-stacking interactions. Because of these features, the catalyst is able to produce blocks of atactic and isotactic polypropylene. {pi}-Stacking clearly influences the confirmations that the catalyst adopts during the polymerization process. By adding substituents to the phenyl groups more » or changing the solvent, one can alter the {pi}-stacking effects to favor one conformation or the other. 18 refs., 2 figs. « less
Prospects for the Prevention and Therapy of Infections with the Human Immunodeficiency Virus

The current epidemic of acquired immunodeficiency syndrome (AIDS) poses a major threat to our population. Urgently needed are both a vaccine to prevent infection with the etiologic retrovirus, human immunodeficiency virus (HIV), and safe, effective antiviral agents to treat those individuals already infected. The elucidation of viral replicative mechanisms has allowed the development and testing of several agents active against HIV in vitro. Inhibitors of reverse transcriptase that have demonstrated activity include azidothymidine, phosphonoformate, antimoniotungstate (HPA-23), and suramin. Ribavirin and recombinant interferon alpha-A (IFN-alpha-A) also inhibit HIV replication, although their mechanisms of action are less clear. All of these compounds are undergoing early clinical trials in patients with HIV infection. The identification of immunogenic viral proteins may allow the development of one or more subunit vaccines against HIV. Studies are underway to clone appropriate viral genes and incorporate the expressed proteins into vectors for administration. Laboratory models, e.g., chimpanzees, will be inoculated with candidate vaccines and, if successful, this will be followed by clinical trials for safety and efficacy in appropriate human populations seronegative for HIV. Although important problems, such as virus envelope protein variability, need to be addressed, efforts to develop effective vaccines may well prove successful in the years ahead.
Novel use of zebrafish as a vertebrate model to screen radiation protectors and sensitizers

Purpose Zebrafish ( Danio rerio ) embryos provide a unique vertebrate model to screen therapeutic agents easily and rapidly because of their relatively close genetic relationship to humans, ready abundance and accessibility, short embryonal development, and optical clarity. To validate zebrafish embryos as a screen for radiation modifiers, we evaluated the effects of ionizing radiation in combination with a known radioprotector (free radical scavenger Amifostine) or radiosensitizing agent (tyrosine kinase inhibitor AG1478). Methods and materials Viable zebrafish embryos were exposed to 0–10 Gy single-fraction 250 kVp X-rays with or without either Amifostine (0–4 mM) or AG1478 (0–10 μM) at defined developmental stages from 1–24 h postfertilization (hpf). Embryos were examined for morphologic abnormalities and viability until 144 hpf. Results Radiation alone produced a time- and dose-dependent perturbation of normal embryonic development and survival with maximal sensitivity at doses ≥4 Gy delivered before 4 hpf. Amifostine markedly attenuated this effect, whereas AG1478 enhanced teratogenicity and lethality, particularly at therapeutically relevant (2–6 Gy) radiation doses. Conclusions Collectively, these data validate the use of zebrafish as a vertebrate model to assess the effect of radiation alone or with radiation response modulators. Zebrafish embryos may thus provide a rapid, facile system to screen novel agents ultimately intended for human use in the context of therapeutic or accidental radiation exposure.
Fabrication and analysis of a low-loss in-fiber active polymer waveguide

We present a method for fabricating an in-fiber electro-optic polymer waveguide within a D-shaped optical fiber. A combined process of selective chemical etching and spin coating creates a 2-cm in-fiber poly(methyl methacrylate)-DR1 dye polymer waveguide section with an overall insertion loss of ∼1.6 dB at 1550 nm. Numerical simulations show that, for in-fiber polymer waveguides to have low loss, the polymer layer’s thickness must be kept below a certain value so that it will not support slab waveguide modes. Long transition regions between the unetched fiber and the polymer waveguide section also reduce loss. We analyze the efficiency of an in-fiber polymer waveguide by simulating its theoretical performance as an electro-optic modulator.
LSI-Entwicklung und -Fabrikation

After a brief historical review, the key elements of LSI silicon technology are described, using illustrative examples. Superintegration as well as its limits are discussed. The manufacturing process of a superintegrated 64k-bit memory chip shows the essential issues of a modern high-volume production. An outlook exhibits possible developments even in non-silicon technologies.
Potassium transport and content during G1 and S phase following serum stimulation of 3T3 cells

The effect of serum stimulation on unidirectional and net K flux and their relationship to the initiation of DNA synthesis has been investigated in mouse 3T3 fibroblasts. Stimulation of quiescent 3T3 cells with 20% serum results in the initiation of S phase approximately ten hours after serum addition. During transition from G1 to S phase distinct changes in K transport and cellular K content occur. Total unidirectional K influx undergoes an immediate 2-fold increase upon serum addition, an observation in qualitative agreement with previous results (Rozengurt and Heppel, 1975). This total increase in unidirectional K influx represents a proportional increase in the active, ouabain sensitive component and the K-K exchange component. The initial increase in total flux is followed by a gradual decline over a 16-hour period to levels approaching those of quiescent cells. Following the initial increase in unidirectional K influx is an approximately 75% increase in cell K on a per milligram protein basis or a 40% increase on a per volume basis. This increase peaks at four to five hours and then declines to initial levels at 10 to 14 hours. Populations of quiescent cells given 20% serum plus 0.5 mM ouabain simultaneously are totally blocked from entering S phase, as determined by the appearance of 3H-thymidine labeled nuclei. However, if the ouabain is removed after six hours these cells then undergo the same changes in unidirectional K influx and content as serum stimulated cells with entrance into S phase retarded by five to six hours. If ouabain is added to serum stimulated cells at six hours, after the increase in K transport and K content have occurred, entrance into S phase is not entirely blocked. In cells stimulated with serum and 0.5 mM dBcAMP plus 1 mM theophylline simultaneously, entrance into S phase is greatly reduced as compared to serum stimulation only. However, the early and late changes in K flux and K content are not substantially altered. This indicates that the K transport events associated with G1 and early S phase are not directly regulated by changes in cAMP levels which follow serum stimulation.
Cerebral Ventricle Cannulation in the Calf

Abstract A stereotaxic apparatus and procedure for surgically implanting guide cannulae for access to the cerebral ventricles of the calf are described. This type of implant permits chronic ventricular injections and collections of milliliter quantities of cerebrospinal fluid from the nonanesthetized calf.
The construction of orthonormal bases diagonalizing the Discrete Fourier Transform

La transformee de Fourier discrete F(m) sur m points peut etre donnee comme un operateur unitaire sur L 2 (Z/m). Soit Z/m les entiers mod m et L 2 (Z/m) l'espace des fonctions a valeur complexe sur le groupe abelien, Z/m. On considere le probleme de construire une base orthonormale de vecteurs propres pour F(m)