cssi/SciSciGPT-SciSciNet huggingface dataset:
How Fast Do Algorithms Improve? [Point of View]

Algorithms determine which calculations computers use to solve problems and are one of the central pillars of computer science. As algorithms improve, they enable scientists to tackle larger problems and explore new domains and new scientific techniques [1] , [2] . Bold claims have been made about the pace of algorithmic progress. For example, the President’s Council of Advisors on Science and Technology (PCAST), a body of senior scientists that advise the U.S. President, wrote in 2010 that “in many areas, performance gains due to improvements in algorithms have vastly exceeded even the dramatic performance gains due to increased processor speed” [3] . However, this conclusion was supported based on data from progress in linear solvers [4] , which is just a single example. With no guarantee that linear solvers are representative of algorithms in general, it is unclear how broadly conclusions, such as PCAST’s, should be interpreted. Is progress faster in most algorithms? Just some? How much on average?
Renin-Angiotensin System Alterations in the Human Alzheimer's Disease Brain.

BACKGROUND Understanding Alzheimer's disease (AD) in terms of its various pathophysiological pathways is essential to unravel the complex nature of the disease process and identify potential therapeutic targets. The renin-angiotensin system (RAS) has been implicated in several brain diseases, including traumatic brain injury, ischemic stroke, and AD. OBJECTIVE This study was designed to evaluate the protein expression levels of RAS components in postmortem cortical and hippocampal brain samples obtained from AD versus non-AD individuals. METHODS We analyzed RAS components in the cortex and hippocampus of postmortem human brain samples by western blotting and immunohistochemical techniques in comparison with age-matched non-demented controls. RESULTS The expression of AT1R increased in the hippocampus, whereas AT2R expression remained almost unchanged in the cortical and hippocampal regions of AD compared to non-AD brains. The Mas receptor was downregulated in the hippocampus. We also detected slight reductions in ACE-1 protein levels in both the cortex and hippocampus of AD brains, with minor elevations in ACE-2 in the cortex. We did not find remarkable differences in the protein levels of angiotensinogen and Ang II in either the cortex or hippocampus of AD brains, whereas we observed a considerable increase in the expression of brain-derived neurotrophic factor in the hippocampus. CONCLUSION The current findings support the significant contribution of RAS components in AD pathogenesis, further suggesting that strategies focusing on the AT1R and AT2R pathways may lead to novel therapies for the management of AD.
Business ethics as practice : ethics as the everyday business of business

In recent years, a succession of corporate scandals has rocked the international business community. As a result, many companies have invested considerable time, money and effort on the development of ethics management programs. However, in many cases, such programs are nothing more than insurance policies against corporate liability, designed merely to limit the fallout of scandals should they occur. In Business Ethics as Practice, Mollie Painter-Morland urges us to take business ethics seriously by reconsidering the role of ethics management within organizations. She redefines the typical seven-step ethics management program from within – challenging the reader to reconsider what is possible within each aspect of this process. In doing so, she draws on the insights of Aristotle, Nietzsche, Heidegger, Foucault and numerous contemporary organizational theorists and sociologists to create the space for the emergence of a morally responsive corporate ethos.
Research in machine learning: recent progress, classification of methods, and future directions

Abstract The last few years have produced a remarkable expansion of research in machine learning. The field has gained an unprecedented popularity, several new areas have developed, and some previously established areas have gained new momentum. While symbolic methods, both empirical and knowledge intensive (in particular, inductive concept learning and explanation-based methods), continued to be exceedingly active (see Parts Two and Three of the book, respectively), subsymbolic approaches, especially neural networks, have experienced tremendous growth (Part Five). Unlike past efforts that concentrated on single learning strategies, the new trends have been to integrate different strategies and to develop cognitive learning architectures (Part Four). There has been an increasing interest in experimental comparisons of various methods, and in theoretical analyses of learning algorithms. Researchers have been sharing the same data sets and have applied their techniques to the same problems in order to understand the relative merits of different methods. Theoretical investigations have brought new insights into the complexity of learning processes (Part Six). This chapter gives a brief account of the recent progress and prospective research directions in the field, attempts to clarify some basic concepts, proposes a multicriteria classification of learning methods, and concludes with a brief description of each chapter.
Book Review - Hubbert's Peak: The Impending World Oil Shortage

This book provides a thorough explanation of the origin, exploration, production, and marketing of oil. The author’s goal is to increase awareness (if not an attempt to raise the alarm) that an unprecedented energy crisis is just over the horizon. Kenneth Deffeyes predicted an impending oil crisis by 2004 which will manifest itself by a dramatic increase in oil prices. Does this sound familiar? The few years since this book has been published seem only to provide additional proof that Deffeyes’ prophecies might be correct. The author goes beyond Hubbert’s model; not only does he model current oil production and reserves to forecast an impending peak, but he also geographically and experimentally explains why oil reserves and oil recovery will peak soon and why even generous oil reserve estimates will lead only to a few years’ variation in the expected production peak.
Biophysical characteristics of peach trees infected with phony peach disease.

Abstract The effect of phony peach disease (PPD) on leaf gas exchange, several growth parameters, and plant water relations was assessed on Prunus persica (L.) Batsch “Flordaking” peach. The presence of xylem-limited bacteria (XLB) in roots and stems of trees with PPD symptoms was confirmed by phase-contrast microscopy and successful culture on periwinkle wilt medium. Mean predawn leaf conductance (gl) was 0 mmol m−2s−1 and shoot water potential (Ψsw) was −0·15 MPa for both PPD and control trees. The only difference between treatments occurred at midday where gl and Ψsw of PPD trees were reduced by 25 and 18%, respectively. Reductions in terminal growth, gl, transpiration rate, net CO2 assimilation rate and Ψsw were poorly correlated with XLB concentration in roots. Turgor pressure (Ψp) of shoots was not reduced with PPD. Dwarfing associated with PPD was not consistently related to the bulk modulus of elasticity (e) of terminal growth. Stomatal closure of PPD and control leaves occurred at similar leaf water potentials (ΨLw) although in neither case was a distinct threshold ΨLw for stomatal closure apparent. Trees severely infected with PPD (8cm terminal growth/year) manifested a 12–18% reduction in midday net CO2 assimilation rate, a 15–25% reduction in midday gl, and a 0·2-0·6 MPa decline in midday Ψsw throughout the spring and summer. The decline in A appeared to be due to stomatal closure associated with increased water stress. Significant increases in Mn, Na, and Al were diagnosed in leaves of PPD-trees. The hydraulic conductance (L) of root terminals and root and stem pieces was not significantly affected by PPD. Root L, whether determined with vacuum or pressure, was not related to extractable XLB cm−3 xylem. In contrast to earlier reports, we conclude that the relatively minor reductions in midday Ψsw may be insufficient to entirely explain PPD symptoms. The relevance of these findings is discussed.
The Food and Drug Administration's Post‐Licensure Rapid Immunization Safety Monitoring program: strengthening the federal vaccine safety enterprise

In 2009, the Department of Health and Human Services created the new Post-Licensure Rapid Immunization Safety Monitoring (PRISM) program, which used data from national health insurance plans and immunization registries to monitor the safety of the H1N1 influenza vaccine. PRISM has now been integrated into the FDA's Mini-Sentinel pilot program. It strengthens the federal vaccine safety enterprise in two important ways. First, PRISM monitors the largest US general population cohort designated for active surveillance of vaccine safety. Second, PRISM links data from health plans with data from state and city immunization registries, which were a crucial source of exposure data in the H1N1 vaccine evaluation. The Mini-Sentinel data that support PRISM are updated quarterly, and PRISM can conduct medical record review for validation of computerized data. The FDA has structured PRISM as a program that includes specific vaccine evaluations, development of an operational framework to guide the design of vaccine safety evaluations, and development of new statistical methods. A human papillomavirus vaccine, Gardasil, and two rotavirus vaccines, RotaTeq and Rotarix, have been chosen for surveillance in the current cycle because their evaluations would benefit most from PRISM's large cohort size. The PRISM program creates important opportunities by offering a robust, responsive new surveillance program with features complementary to existing systems. Methodological and logistical lessons can be shared among PRISM and other surveillance systems, offering potential synergies. FDA and PRISM will work to maximize the program's unique strengths and contributions to a unified federal vaccine safety enterprise.
Erdõs on Graphs : His Legacy of Unsolved Problems

1. Introduction 2. Ramsey Theory 3. Extremal Graph Theory 4. Coloring, Packing, and Covering 5. Random Graphs and Graph Enumeration 6. Hypergraphs 7. Infinite Graphs
Baselines to Detect Population Stability of the Threatened Alpine Plant Packera franciscana (Asteraceae)

Abstract. Population size and density estimates have traditionally been acceptable ways to track species' response to changing environments; however, species' population centroid elevation has recently been an equally important metric. Packera franciscana (Greene) W.A. Weber and A. Love (Asteraceae; San Francisco Peaks ragwort) is a single mountain endemic plant found only in upper treeline and alpine talus habitats of the San Francisco Peaks in northern Arizona and is listed by the U.S. Fish and Wildlife Service as a Threatened species under the Endangered Species Act. We used 2 recreational trails, which pass through its elevational distribution in the Kachina Peaks Wilderness Area, as sampling transects to estimate population density and distribution because it was not possible to sample further from the trail due to loose volcanic talus and consequent disturbance of P. franciscana plants. Between-year comparisons of ramet density, population centroid elevations, and mid-September flowering or fruiting...
An Analytical Approach to the Adoption of Asymmetric Bidirectional Firewalls: Need for Regulation?

Recent incidents of cybersecurity violations have revealed the importance of having firewalls and other intrusion detection systems to monitor traffic entering and leaving access networks. But the adoption of such security measures is often stymied by `free-riding' effects and `shortsightedness' among Internet service providers (ISPs). In this work, we develop an analytical framework that not only accounts for these issues but also incorporates technological factors, like asymmetries in the performance of bidirectional firewalls. Results on the equilibrium adoption and stability are presented, along with detailed analysis on several policy issues related to social welfare, price of anarchy, and price of shortsightedness.
Intracardiac Echocardiography Use in Children

In their article, Bartel et al1 demonstrate the superiority of intracardiac echocardiography over conventional transesophageal echocardiography in guiding device closure of atrial septal defects (ASDs) and patent foramen ovale (PFO).1 ASDs and PFOs can be successfully closed in children under transesophageal echocardiography guidance.2,3 Because the authors have not provided the reader with the age of their patients, one is left to presume that the study was carried out in adults (from the 11F sheath used). Hence, their study may not demonstrate that intracardiac echocardiography monitoring can …
Nontuberculous, nonleprous mycobacterioses

Summary The role of tuberculoid mycobacteria as causes for disease in humans is continually expanding. New species continue to be recognized as pathogens, and the increasing number of immunosuppressed patients with ever lengthening survivals increases the potential for these environmental Mycobacterium spp. to become pathogens. The decline in incidence of tuberculosis has made disease caused by these organisms of greater importance. Much remains to be learned clinically, microbiologically, and genetically about tuberculoid bacilli. The optimal treatment for most diseases caused by the tuberculoid mycobacteria is unknown, susceptibility testing has frequently failed to predict clinical responses, and many species are resistant to all conventional anti-tuberculous agents. Great attention by clinicians to the disease potential of these organisms and by pharmaceutical companies to the need for better therapeutic agents will be required to control these not so anonymous and certainly not atypical mycobacteria.
Alteration of human accessory cell function by heat treatment: Role of IL-1 and class II MHC antigens

Heat-treated monocytes (1 hr, 45 degrees C) cannot present soluble antigen or mitogen to purified autologous T cells. This is despite normal viability and normal expression of class II MHC antigens. They do not secrete IL-1 nor stimulate secretion of IL-2 by T cells. Addition of exogenous IL-1 or IL-2 does not, however, reconstitute the response to soluble antigen. Furthermore, even after overnight pulsing with antigen prior to heat treatment under circumstances in which the antigen is known to be appropriately processed, stimulation of T-cell proliferation still does not occur. Thus there appear to be at least two discrete lesions produced by heating: failure of IL-1 production, per se, and intrinsic failure to present previously processed antigen. It is also hypothesized that heat treatment may produce alterations in Ia molecules which specifically disallow transduction of the proliferation signal to T cells.
Encouraging Students to Apply Human Sexuality Material to Themselves by Using Integration Papers

ABSTRACT This paper discusses the use of integration papers in human sexuality courses. Integration papers allow students to apply the material they have learned in the course to themselves, which can make the learning experience more powerful. The papers also allow instructors to assess what students have learned by taking the course instead of prior knowledge. A detailed description of the paper assignment and some considerations for implementing an assignment like this are given.
Genetic analysis of coevolution between plants and their natural enemies

Plants exhibit a diverse array of characteristics that have been interpreted as functioning primarily as defenses against natural enemies, such as pathogens and herbivores. Recent genetic analyses of resistance provide evidence supporting this interpretation. In addition, these analyses also support a key assumption underlying models of the evolution of resistance (i.e. that resistance is costly) and suggest that the outcome of coevolution is often not explainable in terms of pairwise interactions between a plant and individual natural enemies (i.e. coevolution is often likely to be diffuse rather than pairwise).
A time to focus on patients, not profit.

Allocution du President: aspects socio-economiques de la radiologie, les abus, les relations entre medecins et patients. Evolution des rapports entre la radiologie et les services de sante
Fracture mechanical character of small cracks in polycrystalline materials: concept and numerical K calculations

Abstract The impact of local variations in elastic modulus on the fracture mechanical character of “microstructurally small” cracks commonly encountered in early stages of fatigue in polycrystalline materials, is assessed. In particular, the stress intensity factor (SIF), K , variations along the crack front, influenced by the random crystallographic orientations of grains were numerically calculated for random variations of elastic moduli of grains. A conceptual framework for calculating the K variations due to local anisotropy was established on the basis of the weight function technique for three-dimensional cracks. As a model, an elliptical crack having sizes: three, five and twenty times the grain size, in polycrystalline Ni, Fe and Ti, was considered. Using patterns of random crystallographic orientations of grains, local inhomogeneous stresses that existed over the crack faces were determined on the basis of isostrain condition. These inhomogeneous stresses were used in the weight function-based calculations, to evaluate the effect of these stresses on the K variation along the crack front. It is shown that the effect of local anisotropy on the K variation is significant at small crack sizes and that the fracture mechanical character of microstructurally small cracks is quite different from that of large cracks in the isotropic environment. It is suggested that the local deviations in shapes of microstructurally small cracks, experimentally observed in many materials, are connected to the local K variations and their dependence on crack size, relative to the grain size.
5,6-Unsaturated hexofuranosyl glycosides and 5′,6′-unsaturated hexofuranosyl nucleosides

Methyl 5,6-dideoxy-2,3-O-isopropylidene-alpha-D-lyxo-hex-5-enofuranoside, prepared from methyl 2,3-O-isopropylidene-5,6-di-O-methylsulfonyl-alpha-D-mannofuranoside with sodium iodide in 2-butanone, was acetolyzed and the product coupled with 6-benzamidochloromercuripurine by the titanium tetrachloride method. Removal of the N-benzoyl group with pictic acid afforded 9-(2,3-di-O-acetyl-5,6-dideoxy-beta-D-xylo-hex-5-enofuranosyl)adenine. In a similar manner, methyl 5,6-dideoxy-2,3-O-isopropylidene-alpha-L-lyxo-hex-5-enofuranoside was prepared from L-mannose and converted into 9-(2,3-di-O-acetyl-5,6-dideoxy-beta-L-xylo-hex-5-enofuranosyl)adenine, further de-esterified to give the free nucleoside. 2,3:5,6-Di-O-isopropylidene-alpha-L-mannofuranosyl chloride, prepared from L-mannose, gave 9-(2,3-O-isopropylidene-alpha-L-mannofuranosyl)adenine, hydrolyzed into 9-alpha-L-mannofuranosyladenine. Treatment with methanesulfonyl chloride gave the 5',6'-dimethanesulfonate, which gave with sodium iodide in acetone the 5',6'-unsaturated nucleoside, further hydrolyzed into 9-(5,6-dideoxy-alpha-L-lyxo-hex-5-enofuranosyl)adenine.
Dirtier Air from a Weaker Monsoon

The level of air pollution in China has much increased in the past decades, causing serious health problems. Among the main pollutants are aerosols, also known as particulate matter: tiny, invisible particles that are suspended in the air. These particles contribute substantially to premature mortality associated with cardiopulmonary diseases and lung cancer1. The increase of the aerosol level in China has been commonly attributed to the fast rise in pollutant emissions from the rapid economic development in the region. However, writing in Geophysical Research Letters, Jianlei Zhu and colleagues2 tell a different side of the story: using a chemical transport model and observation data, they show that the decadal scale weakening of the East Asian summer monsoon has also contributed to the increase of aerosol concentrations in China. The life cycle of atmospheric aerosols starts with its emission or formation in the atmosphere. Some aerosol components such as dust, soot and sea salt are emitted directly as particles to the atmosphere, but others are formed there by way of photochemical reactions. For example, sulphate and nitrate aerosols are produced from their respective precursor gases, sulphur dioxide and nitrogen oxides. Aerosol particles can be transported away from their source locations by winds or vertical motion of the air. Eventually, they are removed from the atmosphere by means of dry deposition and wet scavenging by precipitation. Measurements generally show that aerosol concentrations over Asia are lowest during the summer monsoon season3, because intense rainfall efficiently removes them from the air. The East Asian summer monsoon extends over subtropics and mid-latitudes. Its rainfall tends to concentrate in rain belts that stretch out for many thousands of kilometres and affect China, Korea, Japan and the surrounding area. Observations suggest that the East Asian summer monsoon circulation and precipitation have been in decline since the 1970s4. In particular, a weaker East Asian summer monsoon is characterized by weaker southerly or southwesterly winds, a deficit in rainfall over northern China and larger rainfalls in southern China. By contrast, when the East Asian summer monsoon is strong, the southerly winds and strong rainfalls extend to northern China. The decadal scale decline in the strength of the East Asian summer monsoon since the 1970s would imply an increase in aerosol concentrations in northern China, north of 28deg N, and a decrease in southern China if emissions were kept the same. One obvious reason for this direction of aerosol change is that the reduction of monsoon rainfall in northern China would cause less wet scavenging of aerosols by precipitation. Zhu et al.2 investigated this relationship between aerosol concentrations and the strength of the East Asian summer monsoon and showed that the two parameters have strong negative correlations: the summer aerosol concentrations near the surface over eastern China.
Thermal inertia mapping of Mars from 60°S to 60°N

Twenty-micrometer brightness temperatures are used to derive the thermal inertia for 81% of the Martian surface between latitudes ±60°. These data were acquired by the two Viking Infrared Thermal Mappers in 1977 and 1978 following the two global dust storms of 1977. The spatial resolution used is 2° in latitude by 2° in longitude and the total range in derived inertia is 1 to 15 × 10−3 cal cm−2 sec−12°K−1. The distribution of thermal inertia is strongly bimodal with all values of thermal inertia less than 4 × 10−3 cal cm−2 sec−12°K−1 being associated with three disjoint bright regions mostly in the northern hemisphere. Sufficient dust is raised in global storms to provide fine material adequate to produce these low-inertia areas but the specific deposition mechanism has not been defined. At the low resolution used, no complete exposures of clean rock were found. There is some tendency for darker material to be associated with higher thermal inertia, although the trend is far from one to one. The distribution of high- and low-inertia areas is sufficiently nonrandom to produce a variation in whole-disk brightness temperature with central meridian longitude. This variation and the change in surface kinetic temperature associated with dust storms are factors in establishing the whole-disk brightness temperature at radio and infrared wavelengths and will be important for those who use Mars as a calibration source.
Dynamic acousto-optic photopolarimeter/spectrophotopolarimeter

We propose a novel technique for a new division-of-amplitude photopolarimeter capable of complete measurement of the state of po- larization of light, as determined by the four Stokes parameters. This photopolarimeter uses an acousto-optic cell in the Raman-Nath regime as a beam splitter to divide the incident beam into four or more compo- nents that are used to determine the four Stokes parameters of the inci- dent beam. The acousto-optic photopolarimeter uses no movable parts and thus rapid and simultaneous measurements of the four Stokes pa- rameters are obtained. The instrument matrix of this instrument is non- singular, hence the state of polarization is completely determined. The acousto-optic photopolarimeter utilizes the useful dynamic grating prop- erty that functions as a temporary beam splitter. Power distribution and angle deviations can be easily controlled by varying the driving acousto- optic intensity and frequency. When properly enhanced, this dynamic property can be very useful for several in-line analysis applications.
Patterns of cleaning behaviour on coral reef fish by the anemoneshrimp Ancylomenes pedersoni

Little is known about the cleaning behaviour of shrimps in comparison to that of cleaner fish, and only recently have cleaner shrimps been shown to remove parasites effectively from coral reef fish. Here we describe patterns of cleaning interactions between Pederson shrimp Ancylomenes pedersoni and fish clients in St Thomas, US Virgin Islands. Clients observed here were members of at least 16 fish families, including three previously unreported client families. Most cleans lasted <20 seconds; surgeonfish were cleaned most frequently, but lizardfish and groupers received the longest cleans. The shrimp formed social groups of varying sizes on individuals of the host sea anemone Bartholomea annulata, which served as the centres of their cleaning stations. The number and duration of cleans per station increased with the number of resident shrimp, however most anemones hosted small groups of fewer than four individuals, while larger groups of up to nine individuals were relatively rare. Some client fish chased away other fish and competitively excluded them from anemone stations. We conclude that these shrimp clean a wide diversity of clients, vary their clean duration with fish identity, and clean more when in large groups. In addition, clients in part control these patterns of interaction by interfering with access to these stations by other clients.
New small-diameter fiber optic absorbance sensor for continuous spectral scanning

A new efficient fiber optic absorbance sensor is described. The sensor can be configured with optical pathlengths from a few millimeters to 10 cm while maintaining high throughput. The sensor contains a graded index (GRIN) microlens which is ground for a specific sensor optical configuration. The sensor is able to be configured in several diameters ranging from sizes that fit within clinically acceptable gauge hypodermic needles to several millimeter diameter sizes. The sensor has currently been tested for the near-UV-VIS and near-IR spectral regions. Optical test results for several sensor sizes are presented and compared to sensor configurations described previously in the literature. A brief analysis of the sensor design is given in terms of the physical optics of the graded-index lens/multimode fiber optic couples which lead to high optical efficiencies. Example numerical simulations of the sensor optical efficiency are presented and compared with experimental results. Sample spectra and performance results also are presented.
Importance of photon interaction data for medical imaging and images of soft materials using x-ray microtomography

Photon interaction cross sections for a few biological materials are calculated at 60 keV using non-relativistic form factors and the incoherent scattering function approximation. Compton, Rayleigh and total scattering cross sections were estimated in the momentum transfer region 0 to 5A 0-1 for simulation and compilation purposes. Rayleigh scattering cross sections for water are estimated using the molecular form factors of Morin at low photon energies. Computed tomographic images of a few soft materials are obtained using a tomographic system based on an image intensifier. It consists of a charged coupled device camera and an acquisition board. The charge coupled device and the acquisition board allows image processing, filtration and restoration. A reconstruction programme, written in PASCAL is able to give the reconstruction matrix of the linear attenuation coefficients, and simulates the matrix and the related tomography. X-ray imaging is a well established technique of detecting strongly attenuating materials as distinguished from weakly attenuating materials. The image contrast between the weakly attenuating materials can be enhanced by optimum selection of the X-ray energy and improving the spatial resolution.
Two forms of sustained xanthophyll cycle‐dependent energy dissipation in overwintering Euonymus kiautschovicus

Seasonal differences in PSII efficiency (F v /F m ), the conversion state of the xanthophyll cycle (Z + A)/(V + A + Z), and leaf adenylate status were investigated in Euonymus kiautschovicus. On very cold days in winter, F v /F m assessed directly in the field remained low and Z + A high throughout day and night in both sun and shade leaves. Pre-dawn transfer of leaves from subfreezing temperatures in the field to room temperature revealed that recovery (increases in F v /F m and conversion of Z + A to violaxanthin) consisted of one, rapid phase in shade leaves, whereas in sun leaves a rapid phase was followed by a slow phase requiring days The pre-dawn ATP/ADP ratio, as well as that determined at midday, was similar when comparing overwintering leaves with those sampled in the summer, although pre-dawn levels of ATP + ADP were elevated in all leaves during winter relative to summer. After a natural transition to warmer days during the winter, pre-dawn F v /F m and Z + A in shade leaves had returned to values typical for summer, whereas in sun leaves F v /F m and Z + A levels remained intermediate between the cold day in winter and the summer day. Thus two distinct forms of sustained (Z +A)-dependent energy dissipation were identified based upon their differing characteristics. The form that was sustained on cold days but relaxed rapidly upon warming occurred in all leaves and may result from maintenance of a low lumenal pH responsible for the nocturnal engagement of (Z + A)-dependent thermal dissipation exclusively on very cold days in the winter. The form that was sustained even upon warming and correlated with slow Z +A to violaxanthin conversion occurred only in sun leaves and may represent a sustained engagement of (Z + A)-dependent energy dissipation associated with an altered PSII protein composition In the latter, warm-sustained form, uncoupler or cycloheximide infiltration had no effect on the slow phase of recovery, but lincomycin infiltration inhibited the slow increase in F v /F m and the conversion of Z +A to violaxanthin.
The influence of platinum on the failure of EBPVD YSZ TBCs on NiCoCrAlY bond coats

Abstract The failure of electron beam physical vapor deposition yttria stabilized zirconia thermal barrier coatings (TBCs) on NiCoCrAlY bond coats is described. It is shown that defects in the as-processed bond coats are responsible for TBC failures. By using a thin platinum layer deposited upon the NiCoCrAlY bond coat, it is shown that the lives of TBCs on such bond coats can be significantly extended since the as processed defects are removed.
Identification of the receptor-associated signaling enzymes that are required for platelet-derived growth factor-AA-dependent chemotaxis and DNA synthesis.

Activation of the platelet-derived growth factor (PDGF) α receptor (αPDGFR) leads to cell migration and DNA synthesis. These events are preceded by the ligand-induced tyrosine phosphorylation of the receptor and its association with SH2-containing signaling enzymes including Src family members (Src), the phosphotyrosine phosphatase SHP-2, phosphatidylinositol 3-kinase (PI3K), and phospholipase C-γ1 (PLCγ). In this study, we sought to systematically evaluate the relative roles of the signaling enzymes that are recruited to the αPDGFR for DNA synthesis and cell migration. Our approach was to generate and characterize tyrosine to phenylalanine αPDGFR mutants that failed to associate with one or more of the above listed signaling enzymes. In a 3T3-like cell line (Ph cells), PDGF-dependent DNA synthesis was strictly dependent on only one of the receptor-associated proteins, PI3K. In contrast, multiple signaling enzymes were required for maximal chemotaxis, as receptors unable to associate with either Src, PI3K, or PLCγ initiated chemotaxis to 4, 47, or 56% of the wild-type level, respectively. Furthermore, coexpression of mutant receptors revealed that these signaling enzymes do not need to be on the same receptor for a cell to respond chemotactically to PDGF. We conclude that for the αPDGFR, PI3K plays a major role in initiating DNA synthesis, whereas PI3K, PLCγ, and especially Src are required for chemotaxis.
A review of the use of loss on ignition as a measurement of total volatiles in whole-rock analysis

The use of loss on ignition (LOI) in whole-rock analysis is evaluated in the modern context — as a measurement of total volatiles, mainly added to the other oxides to assess analytical accuracy by testing whether or not the total is 100.0 ± − 1.0%. By measuring LOI- and FeO-decrease with time for several igneous rocks, it is demonstrated that the simple determination of weight loss after ignition at 1000°C, as a measurement of the volatile content, is interfered with by ferrous-iron oxidation. It is shown that ferrous-iron oxidation is virtually complete, and that the LOI measurement can be corrected for this interference if the initial ferrous/ferric ratio is known. If the ferrous/ferric ratio is not measured, total Fe must be reported as Fe2O3 in which case, when the oxides are summed, an accurate total is obtained (although an accurate measurement of total volatiles is not). It is also shown that ignition should be carried out at greater than 900°C, preferably at 1000°C, and that, in practice, 1 hr. is probably sufficient time to achieve virtually complete expulsion of volatiles and conversion of ferrous to ferric oxide in most igneous rocks.
Time–eigenvalue calculations in multi-region Cartesian geometry using Green’s functions

Abstract We have continued the progression of providing benchmark-quality eigenvalue calculations in multi-region Cartesian geometry by reformulating the effective multiplication equations to calculate time eigenvalues. As with effective multiplication eigenvalues, there are few benchmark-quality solutions for time–eigenvalue calculations in multi-region multiplying systems, especially for systems that have divergent temporal neutron populations. The purpose of this paper is to describe the reformulations required and to add benchmark-quality calculations for several test problems. Green’s functions are used to model a multi-region, one-group, isotropically scattering, multiplying system in Cartesian geometry to obtain boundary flux values for a time–eigenvalue search and subsequent eigenfunction calculation. As usual with multi-region Cartesian systems, the solution is facilitated using (1) Placzek’s lemma, which allows us to consider a multi-region system one region at a time as an infinite medium, and (2) the calculation of the Green’s function solution for a nonphysical infinite multiplying medium.
Translocation and Metabolism of Injected Maleic Hydrazide in Silver Maple and American Sycamore Seedlings

Studies were conducted to determine the fate of 14C-maleic hydrazide injected into the stem xylem of 1-year-old silver maple (Acer saccharinum L.) and American sycamore (Platanus occidentalis L.) seedlings. Maleic hydrazide was found to translocate to all parts of the plant within 1 day after treatment. The autoradiographs indicated that the radioactivity was accumulated in meristematic regions of the leaves. A significant amount (over 15% of the applied 14C) was exuded out of the roots into the nutrient solution after 30 days. The 14C in the nutrient solution was in the form of unchanged maleic hydrazide, whereas in plant tissue a metabolite possibly a conjugate with sugar was formed. With the passage of time, the amount of metabolite seemed to increase in proportion to that of maleic hydrazide. Approximately 30% of the applied 14C was unextractable with methanol after 30 days.
Solution and Structural Characterization of Iron(II) Complexes with Ortho-Halogenated Phenolates: Insights Into Potential Substrate Binding Modes in Hydroquinone Dioxygenases

The new ligand cis,cis-1,3,5-tris-(E)-(tolylideneimino)cyclohexane (TACH-o-tolyl) forms a 1:1 complex with iron(II). Addition of substituted phenolates forms 1:1:1 ligand:iron:phenolate complexes, which have been characterized both in the solid state and in solution. There is complete binding of the phenolate to the complex only when there are ortho-halogens on the phenolate. The tertiary complexes with ortho-halo-substituted phenolates exhibit short Fe-halogen distances, and the complex containing a non-coordinating but similarly sized ortho-methyl phenolate has a significantly different conformation and coordination geometry. Therefore, it is likely that the metal-halogen interaction stabilizes the complexes. The iron(II)-halogen interaction in these complexes may explain the substrate specificity of PcpA and LinE, enzymes that preferentially bind phenols and hydroquinones containing halogen substituents in ortho positions.
The role of the National Library of Medicine in the national biomedical library network.

Summary The scientfic revolution of the twentieth century must be accompanied by technological improvement in information science which will make knowledge generated by research readily available to all who need to apply it for the ultimate benefit of mankind. The concepts of organization of existing library resources augmented and linked by new technologies we believe represent the most economic approach to improvement of biomedical communications. We recognize that more sophisticated information systems will emerge and that ultimately the medical library network must fit into the structure of a national information system. The on-going cybernetic revolution affects language, information, and society broadly. As a strong nation requires a healthy scientific base, so does a strong science require excellent communications. As an instrument invented by society, the library will be governed to a large degree by scientific and technological developments. We believe that libraries now have the proper attitude and interest to utilize and capitalize upon the important contributions of mathematics to medicine. Communications technology is now fairly well developed. Where we are lacking is in resources and performance.
PLANT-GROWTH INHIBITION BY SOME FATTY ACIDS AND THEIR ANALOGUES.

FATTY acids per se were found to affect respiratory activity, phosphorylation, and several other metabolic processes in studies with animal tissues1. Many specific inhibitory effects of fatty acids, such as inhibition of kidney enzyme activity, bacteria and virus growth, and cholesterol synthesis are also reported.
Putting the Squeeze on Phototransduction

The study of phototransduction—the conversion of light into electrical signals—in the fruit fly Drosophila melanogaster has presaged many advances in our understanding of cell signaling and sensory biology over the past two decades. Notably, it was in this system that the transient receptor potential (TRP) ion channels were identified ( 1 – 3 ), a family that numbers in the dozens in vertebrate genomes ( 4 ). Vertebrate TRP channels, which were first reported as the transducers of sensory processes including thermosensation and pheromone detection ( 5 , 6 ), have since been found to participate in nearly all areas of cellular physiology ( 4 ). For fly phototransduction, one question has remained conspicuously unanswered: How does a light stimulus lead to the opening of TRP channels? On page 260 of this issue, Hardie and Franze ( 7 ) report a surprising link between light-activated changes in membrane tension and the opening of TRP channels that may be the long-awaited answer.
Fourth-order vacuum-polarization contribution to the Lamb shift.

The vacuum-polarization contribution to the two-loop ground-state self-energy of hydrogenic ions is calculated with an exact Dirac-Coulomb propagator. Agreement at low Z with previous calculations is found and predictions for the effect at high Z are presented. \textcopyright{} 1996 The American Physical Society.
Terrain classification of ladar data for bare earth determination

Terrain classification, or bare earth extraction, is an important component to LADAR data analysis. The terrain classification approach presented in this effort utilizes an adaptive lower envelope follower (ALEF) with an adaptive gradient operation for accommodations of local topography and roughness. In order to create a more robust capability, the ALEF was modified to become a strictly data driven process that facilitates a quick production of the data product without the subjective component associated with user inputs. This automated technique was tested on existing LADAR surveys over Wyoming's Powder River Basin and the John Starr Memorial Forest in Mississippi, both locations with dynamic topographic features. The results indicate a useful approach in terms of operational time and accuracy of the final bare earth recovery with the advantage of being fully data driven.
Hertzian fracture of textured Si3N4

The Hertzian fracture behavior of a fine grained silicon nitride with an aligned microstructure was investigated. Fracture toughness anisotropy has previously been related to quantitative texture analysis in silicon nitride and ceramic composites using Vickers indentation. Indentation with hard spheres on hot pressed and plane-strain forged silicon nitrides on varying surface orientations results in profound demonstrations of crack initiation and propagation. Crack initiation was observed to occur at orientations of lowest toughness followed by completion of surface cracking at higher loads. In plane-strain forged materials, the observed elliptical cracks resulted from fracture toughness anisotropy. Sliding ball tests demonstrate that the wear behavior of this material depends on sliding plane, direction and sign of direction, implying the ability to produce more wear resistant materials through preferred microstructural orientation.
Impacts of Child Care Subsidies on Family and Child Well-Being.

Abstract This cross-sectional study compares 52 working poor families receiving subsidies for child care with 50 demographically matched families drawn from the subsidy waiting lists across three sets of variables: (1) maternal employment and income, (2) child care, and (3) child well-being. Compared to mothers from waiting lists, mothers receiving subsidies for their child’s care were more likely to be employed, spent half as much of their income on child care, and were less likely to be very poor. Compared to children on waiting lists, children receiving subsidies for child care were more likely to be in a formal licensed child care center, have more stable care, and have mothers who were more satisfied with their child care arrangement.
Considerations for the performance evaluation of a geostationary satellite with an on-board Internet router

The Internet protocol routing in space (IRIS) is a new network capability that will extend the Internet into space by placing an IP router on-board a commercial geostationary orbit satellite. IRIS is being developed by an industry group, under auspices of the United States Department of Defense as a Joint Capability Technology Demonstration (JCTD). One of the goals of the IRIS JCTD is to assess the network capability and operational utility of an IP router in space through a series of demonstrations. This paper focuses on the laboratory-based technical demonstrations, which will evaluate the network features and service capabilities of IRIS, from a user perspective. First, we provide some general considerations for setting up a test bed capable of simulating traffic and user networks over an emulated IRIS node. Then we present some preliminary results, primarily derived from the quality of service and bandwidth on demand capabilities of IRIS. (7 pages)
Effect of a synthetic carboxy-terminal peptide of α2-antiplasmin on urokinase-induced fibrinolysis

alpha(2)-Antiplasmin (alpha(2)AP) interferes with the binding of plasminogen to fibrin because lysine residues in its carboxy-terminal region compete with those in fibrin, presumably the same way that free lysine or epsilon-aminocaproic acid (EACA) inhibits plasminogen binding to fibrin. While this overall process causes an inhibition of fibrinolysis, the converse was observed with a 26-residue synthetic peptide (AP26) corresponding to the carboxy-terminal region of alpha(2)AP. The AP26 peptide, in fact, accelerated urokinase-induced lysis of (1) fully crosslinked fibrin with complete gamma-dimer and alpha-polymer formation; (2) partially crosslinked fibrin that had undergone only gamma-dimerization; and (3) noncrosslinked fibrin. The AP26 peptide also inhibited factor XIIIa-catalyzed crosslinking of fibrin alpha-chains, and this also accelerated lysis of fibrin. EACA had no effect. In the presence of noncrosslinked fibrin, AP26 promoted plasminogen activation by urokinase and fibrinolysis. EACA only slightly increased the rate of plasminogen activation, and as expected, it inhibited fibrinolysis. Since AP26 peptide enhanced the lysis of partially crosslinked and noncrosslinked fibrin, our results indicate that inhibition of factor XIIIa-catalyzed alpha-polymer formation by AP26, although associated with accelerated fibrinolysis, is not the primary mechanism. Instead, our data support the conclusion that AP26 enhances the conversion of plasminogen to plasmin approximately 5-fold, probably by inducing a conformational change in plasminogen structure just as occurs with low concentrations of lysine or EACA. At higher concentrations, however, AP26 apparently does not approach the avidity or affinity of lysine or EACA for the kringle structures of plasminogen or plasmin so that their binding to fibrin is blocked. Whether AP26 alone, or as part of another molecule, could have potential for enhancing thrombolysis will require further study.
Overexpression and functional characterization of the extracellular domain of the human α1 glycine receptor

A novel truncated form (residues 1-214, with a randomized C-terminal tail) of the ligand-binding extracellular domain (ECD) of the human alpha1 glycine receptor (GlyR), with amino acids from the corresponding sequence of an acetylcholine binding protein (AChBP) substituted for two relatively hydrophobic membrane-proximal loops, was overexpressed using a baculovirus expression system. The mutant GlyR ECD, named GlyBP, was present in both soluble and membrane-associated fractions after cell lysis, though only the latter appeared to be in a native-like conformation capable of binding strychnine, a GlyR specific antagonist. The membrane-associated GlyBP was solubilized, and detergent/lipid/protein micelles were affinity purified. After detergent removal, GlyBP may be isolated in either aqueous or vesicular form. Binding assays and spectroscopic studies using circular dichroism and FRET are consistent with both forms adopting equivalent native-like conformations. Thus, GlyBP may be isolated as a soluble or membrane-associated assembly that serves as a structural and functional homologue of the ECD of GlyR.