cssi/SciSciGPT-SciSciNet huggingface dataset:
Short latency cerebellar modulation of the basal ganglia

The authors report that in mice, the cerebellum modulates the activity of the striatum via a disynaptic pathway to facilitate optimal motor control. Dysfunction of this pathway can contribute to dystonia.
The rise of supermarkets and changing expenditure patterns of poor rural households case study in the Transkei area, South Africa

Abstract Since the late 1990s, the number of supermarkets in South Africa has been steadily growing. Due to a more effective and efficient management and procurement system, the supermarkets can benefit from economics of scale and sell food at a relative low price. In this paper, we present a case study of two villages in the Transkei area of South Africa. In these poor rural communities, the majority of households now buy their main food items from supermarkets rather than from local shops and farmers. While presenting an important step towards livelihood development and food security, these supermarkets form also a strong competitor for local agricultural sales. The supermarkets provide many food items at lower prices. With an increase in income, the households look for variety and exotism in their food products, and will most likely find this in the supermarkets, rather than the local stores. We argue therefore that development programs should focus on the local growers’ access to the supermarket procurement systems.
Computational Studies of Human Motion

We review methods for kinematic tracking of the human body in video. The review is part of a projected book that is intended to cross-fertilize ideas about motion representation between the animation and computer vision communities. The review confines itself to the earlier stages of motion, focusing on tracking and motion synthesis; future material will cover activity representation and motion generation.
Electronic specific heat of simple metals

Abstract The effect of lattice periodicity on the electronic specific heat of alkali metals is calculated by extending the work of Bellemans and deLeener to finite temperature. Psuedopotentials for these metals are simply taken from band splitting data. The calculation reproduces moderately well the general trend of experimentally measured electronic specific heats. Inclusion of electronphonon effects have no marked effect on these trends but in most cases improve numerical agreement.
Three-dimensional multispecies nonlinear perturbative particle simulations of collective processes in intense particle beams

Collective processes in intense charged particle beams described self-consistently by the Vlasov-Maxwell equations are studied using a 3D multispecies nonlinear perturbative particle simulation method. The newly developed beam equilibrium, stability, and transport (BEST) code is used to simulate the nonlinear stability properties of intense beam propagation, surface eigenmodes in a high-intensity beam, and the electron-proton ($e\ensuremath{-}p$) two-stream instability observed in the Proton Storage Ring (PSR) experiment. Detailed simulations in a parameter regime characteristic of the PSR experiment show that the dipole-mode two-stream instability is stabilized by a modest spread (about 0.1%) in axial momentum of the beam particles.
Removal of organic precursors by permanganate oxidation and alum coagulation

Abstract Much is known about the removal and reaction mechanisms of the naturally occurring precursors of trihalomethanes such as humic and fulvic acids. However, another class of precursors including phenols, anilines and aliphatic diketones has not been thoroughly investigated. This study shows that these truly soluble, monomeric precursors are poorly removed by alum coagulation. The use of permanganate preceding alum coagulation provides a good reduction of chloroform in water samples containing high proportions of monomeric precursors. The process was found to be less effective for water samples containing a high proportion of humic acid. This is possibly due to the degradation products from the permanganate oxidation of humic acid. These degradation products are not readily removed by alum coagulation and become available for subsequent chloroform formation.
Chemical-looping Combustion of Coal-derived Synthesis Gas Over Copper Oxide Oxygen Carriers

CuO/bentonite and CuO-BHA nanocomposites were studied as oxygen carriers in chemical-looping combustion (CLC) of simulated synthesis gas. Global reaction rates of reduction and oxidation, as the function of reaction conversion, were calculated from 10-cycle oxidation/reduction tests utilizing thermogravimetric analysis at atmospheric pressure between 700 and 900 °C. It was found that the reduction reactions are always faster than oxidation reactions; reaction temperature and particle size do not significantly affect the reaction performance of CuO/bentonite. Multicycle CLC tests conducted in a high-pressure flow reactor showed stable reactivity for production of CO2 from fuel gas at 800 and 900 °C and full consumption of hydrogen during the reaction. Results of the tapered element oscillating microbalance showed a negative effect of pressure on the global rates of reduction-oxidation reactions at higher fractional conversions. X-ray diffraction patterns confirmed the presence of CuO in the bulk phase of the oxidized sample. Electron microanalysis showed significant morphology changes of reacted CuO/bentonite samples after the 10 oxidation-reduction cycles above 700 °C in an atmospheric thermogravimetric analyzer. The nanostructured CuO-BHA carrier also showed excellent stability and, in comparison to the CuO/bentonite system, slightly accelerated redox kinetics albeit at the expense of significantly increased complexity of manufacturing. Overall, bothmore » types of CuO carriers exhibited excellent reaction performance and thermal stability for the CLC process at 700-900 °C.« less
Mars - Far-infrared spectra and thermal-emission models

Spectra of Mars from 100 to 360 kaysers were obtained during three different observation periods from NASA's Kuiper Airborne Observatory. Also, a new thermal model was constructed for the surface of Mars, and synthetic spectra were computed from the models to compare with the observations. The models include the effects of a dusty atmosphere which absorbs, scatters, and reradiates energy. The synthetic spectra show significant effects on disk-averaged brightness temperatures, as well as absorption features due to silicate dust. The spectra of Mars, which are ratios of Mars to the moon, do not fit the synthetic spectra unless the surface emissivities of Mars and the moon have different dependencies on wavelength. A possible explanation for this behavior is a difference in soil particle-size distributions between Mars and the moon, with Mars being depleted in large particles compared to the moon. Small particles are consistent with clay minerals which have been suggested elsewhere as constituents of the Martian surface.
Restructuring Intra-urban Space during China's Transition. Jian Feng

(2007). Restructuring Intra-urban Space during China's Transition. Jian Feng. Eurasian Geography and Economics: Vol. 48, No. 3, pp. 380-382.
Ketoconazole and flucytosine alone and in combination against Candida spp. in a neutropenic site in rabbits

Ketoconazole and flucytosine were administered alone and in combination for ten days to rabbits with four candida isolates growing in subcutaneously implanted semipermeable chambers. The peak concentrations of ketoconazole in serum and in the chamber were 20.3 and 3.8 mg/l, respectively, and the concentrations of flucytosine 47.7 and 37.3 mg/l, respectively. The two drugs combined resulted in better fungistatic activity than either drug alone against all four isolates. Correlation of efficacy in the rabbit model with in-vitro MICs was good for flucytosine, but poor for ketoconazole.
Temperature dependence of kinetics of triplet formation in phenazine: analysis by analogue computer

Abstract The temperature dependence of kinetic parameters of triplet phenazine have been determined by analysis of transient response to photoexcitation. The analogue computer used in the analysis is described.
Lattice separation and properties of Wallman type spaces

In this paper, we are primarily concerned with the general Wallman spaces IR (L) andIσRL, associated with an abstract set X and a lattice of subsets of X,L. For a pair of latticesL1 ⊂L2withL1 ⊂L2 we investigate first separation properties and finally we turn attention to the preservation of some of the properties introduced in connection withIσR and the latticesWσ(L) andtWσ(L).
The Algebraic Structure of Physical Quantities

We present a general algebraic basis for arbitrary systems of units such as those used in physical sciences, engineering, and economics. Physical quantities are represented as q-numbers: an ordered pair u = {u,labelu}, that is, u ∈ q = X × WB. The algebraic structure of the infinite sets of labels that represent the “units” has been established: such sets WB are infinite Abelian multiplicative groups with a finite basis. WB is solvable as it admits a tower of Abelian subgroups. Extensions to include the possibility of rational powers of labels have been included, as well as the addition of named labels. Named labels are an essential feature of all practical systems of units. Furthermore, q is an Abelian multiplicative group, and it is not a ring. q admits decomposition into one-dimensional normed vector spaces over the field X among members with equivalent labels. These properties lead naturally to the concept of well-posed relations, and to Buckingham’s theorem of dimensional analysis. Finally, a connection is made with a Group Ring structure and an interpretation in terms of the observable properties of physico-chemical systems is given.
Separating access control policy, enforcement, and functionality in extensible systems

Extensible systems, such as Java or the SPIN extensible operating system, allow for units of code, or extensions, to be added to a running system in almost arbitrary fashion. Extensions closely interact through low-latency but type-safe interfaces to form a tightly integrated system. As extensions can come from arbitrary sources, not all of whom can be trusted to conform to an organization's security policy, such structuring raises the question of how security constraints are enforced in an extensible system. In this paper, we present an access control mechanism for extensible systems to address this problem. Our access control mechanism decomposes access control into a policy-neutral enforcement manager and a security policy manager, and it is transparent to extensions in the absence of security violations. It structures the system into protection domains, enforces protection domains through access control checks, and performs auditing of system operations. The access control mechanism works by inspecting extensions for their types and operations to determine which abstractions require protection and by redirecting procedure or method invocations to inject access control operations into the system. We describe the design of this access control mechanism, present an implementation within the SPIN extensible operating systems, and provide a qualitative as well as quantitative evaluation of the mechanism.
Synthesis of heterarchical manufacturing systems

Abstract The complexity of computer-integrated manufacturing systems with hierarchical architectures grows rapidly with size, resulting in accompanying high costs of development, installation, operation, maintenance, and modification. It is also difficult to introduce fault tolerance into hierarchical structures without significantly increasing system complexity. In the place of a hierarchical structure for manufacturing systems, “cooperative heterarchies” have been suggested in which there are no “higher level” controllers in the system, and each member conforms to certain rules in order to obtain certain privileges. Heterarchical architures offer prospects of: reduced complexity and improved fault tolerance by localizing information and control; reduced software development costs by eliminating supervisory levels; and higher main tainability and modifiability due to improved modularity and self-configurability. Unfortunately, they do not resemble hierarchical management and production control structures, and traditional deterministic design philosophies and methodologies are not necessarily appropriate. This paper is devoted to a discussion of design objectives and philosophies for heterarchical systems. An automated mold production system with a heterarchical architecture is discussed as an example.
Remarkably Efficient Synthesis of 2H-Indazole 1-Oxides and 2H-Indazoles via Tandem Carbon−Carbon Followed by Nitrogen−Nitrogen Bond Formation

Base-catalyzed tandem carbon-carbon followed by nitrogen-nitrogen bond formations quantitatively converted N-alkyl-2-nitro-N-(2-oxo-2-aryl-ethyl)-benzenesulfonamides to 2H-indazoles 1-oxides under mild conditions. Triphenylphosphine or mesyl chloride/triethylamine-mediated deoxygenation afforded 2H-indazoles.
Viscoelastic composite with a cracked layer under anti-plane shear

Abstract A viscoelastic cracked sandwich composite under anti-plane load is presented via the application of the Laplace transform and the complex variable formulation. Using a special technique of analytical continuation associated with the method of image, the triple-layered problem is reduced to a singular function by simple algebraic manipulations. The superposition method and the singular integral equation is applied to deal with the concentrated load and crack problem. Finally, some typical viscoelastic models and its corresponding stresses and stress intensity factors are also discussed. The results show that the time dependent stress intensity factor is affected by the relative strength of creep compliances of each layer.
Catalytic antioxidants and neurodegeneration.

Oxidative stress, resulting from mitochondrial dysfunction, excitotoxicity, or neuroinflammation, is implicated in numerous neurodegenerative conditions. Damage due to superoxide, hydroxyl radical, and peroxynitrite has been observed in diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis, as well as in acute conditions that lead to neuronal death, such as stroke and epilepsy. Antioxidant therapies to remove these toxic compounds have been of great interest in treating these disorders. Catalytic antioxidants mimic the activities of superoxide dismutase or catalase or both, detoxifying superoxide and hydrogen peroxide, and in some cases, peroxynitrite and other toxic species as well. Several compounds have demonstrated efficacy in in vitro and in animal models of neurodegeneration, leading to optimism that catalytic antioxidants may prove to be useful therapies in human disease. Antioxid. Redox Signal. 11, 555–569.
Digital filters using read-only memories

An algorithm, based on the replacement of multiply operations by table lookup, is presented for the computation of low-order digital convolutions.
Workers, Space, and Labor Geography

In this paper I argue that adopting an explicitly spatial theoretical framework can add significantly to our understanding of working-class life. Specifically, I argue that workers are spatial as well as historical social agents and that they seek to shape the economic landscape in ways which facilitate their political and economic goals, though they clearly do not have free range to do so—workers make their own geographies, though not under the conditions of their own choosing. The paper explores how capitalism functions as a spatial system, what this means for workers' spatial praxis, and how workers can try to shape capitalism's geography to their own ends. The paper is in three main sections. The first section lays out the conceptual basis for understanding capitalism as a spatial system. In the second section I examine a number of ways in which a sensitivity to matters spatial can help us understand workers' social praxis. The third section explores some issues related to how the changing geography of capitalism is providing new challenges to workers and organized labor.
Use of Thermodynamics in Examining the Effects of Ocean Acidification

The burning of fossil fuels has increased the concentration of carbon dioxide (CO2) in the atmosphere from 280 ppmv (volume parts per million) to 385 ppmv over the last 200 years. This increase is larger than has occurred over the past 800,000 years. Equilibration of increasing amounts of CO2 with surface waters will decrease the pH of the oceans (called ocean acidification ) from a current value of 8.1 to values as low as 7.4 over the next 200 years. Decreasing the pH affects the production of solid CaCO3 by microorganisms in surface waters and its subsequent dissolution. CO2 dissolution in the ocean can also affect acid–base equilibria, metal complex formation, solid–liquid equilibria, and the adsorption of ions to charged surfaces. Thermodynamic principles can be used to understand these processes in natural waters.
Perceived Barriers to Adopting an Asian-Language Quitline Service: A Survey of State Funding Agencies

This study examined the perceived barriers to adopting an Asian-language quitline service among agencies that fund current state quitline services across the U.S. A self-administered survey on organizational readiness was sent to the funding agencies of 47 states plus Washington D.C. that currently fund state quitlines in English and Spanish, but not in Asian languages (response rate = 58%). The 2010 Census and the 2009 North American Quitline Consortium Survey were used to obtain the proportion of Asians among the state population and state quitline funding level, respectively. The most frequently cited reasons for not adopting an Asian quitline are: the Asian population in the state would be too small (71.4%), costs of service would be too high (57.1%), and the belief that using third-party translation for counseling is sufficient (39.3%). However, neither the actual proportion of Asians among the state population (range = 0.7% to 7.3%), nor the quitline funding level (range = $0.17 to $20.8 per capita) predicts the reported reasons. The results indicate that quitline funding agencies need more education on the necessity and the feasibility of an Asian-language quitline. Three states are currently participating in a multi-state Asian-language quitline in which each state promotes the service to its residents and one state (CA) provides the services for all the states. This centralized multi-state Asian-language quitline operation, which helps reduce practical barriers in adoption and disparity in access to service, could be extended.
Variations of light and temperature regimes and resulting effects on reproductive parameters in medaka (Oryzias latipes)

In seasonally breeding fish species, altered fecundity, fertility, and spawning interval are associated with changes in environmental cues such as temperature and photoperiod. To determine quantitative impact of these cues on a suite of reproductive endpoints, groups of medaka (Oryzias latipes; two breeding pairs per group) were subjected to varying photoperiod and temperature regimes. Embryo production ceased after photoperiod reduction from 16L:8D to 8L:16D (at 258C). A severe decline in production was observed after a temperature decrease of 108C (258 Ct o 158C [16L:8D]). Under reduced photoperiod, histologic analysis showed no mature ova and moderate oocyte atresia in all individuals. However, reduced temperature (158C) produced only mild oocyte atresia and fewer mature ova. Under both reduced photoperiod and reduced temperature regimes, mature spermatozoa were observed. Offspring viability, along with spawning interval, were not affected by photoperiod reduction. Temperature change had no effect on offspring viability but caused an increase in spawning interval. A shortened photoperiod profoundly affected medaka reproduction, whereas decreased temperature reduced, but did not arrest, fertility; reduced photoperiod decreased fecundity. These findings have important implications for culture of medaka as well as use of this teleost model for reproductive toxicology studies.
Quality of care in patients with gout: why is management suboptimal and what can be done about it?

Gout is a common inflammatory arthritis. We know a great deal about its etiopathogenesis and have relatively safe and effective therapies for it. Gout, however, remains a poorly managed disease with mistakes made in securing an accurate diagnosis and in using appropriate therapies for acute and chronic stages of the disease. Synovial fluid analysis with polarizing microscopy is the “gold standard” for confirming the diagnosis of gout but has been used in fewer than 10% of all patients diagnosed with gout. The newly adopted European clinical guidelines offer a practical alternative to synovial fluid analysis, but primary care physicians are not well-versed in their use. Other serious errors in the management of gout are related to the use of medications to treat acute and chronic gout. Frequently, the anti-inflammatory drugs used to treat acute symptoms and urate-lowering drugs used to prevent long-term destruction are improperly dosed, leading to dissatisfaction on the part of patients and physicians. Widespread education about evidence-based diagnostic and treatment guidelines is desperately needed.
Defining conservation priorities for freshwater fishes according to taxonomic, functional, and phylogenetic diversity

To date, the predominant use of systematic conservation planning has been to evaluate and conserve areas of high terrestrial biodiversity. Although studies in freshwater ecosystems have received recent attention, research has rarely considered the potential trade-offs between protecting different dimensions of biodiversity and the ecological processes that maintain diversity. We provide the first systematic prioritization for freshwaters (focusing on the highly threatened and globally distinct fish fauna of the Lower Colorado River Basin, USA) simultaneously considering scenarios of: taxonomic, functional, and phylogenetic diversity; contemporary threats to biodiversity (including interactions with nonnative species); and future climate change and human population growth. There was 75% congruence between areas of highest conservation priority for different aspects of biodiversity, suggesting that conservation efforts can concurrently achieve strong complementarity among all types of diversity. However, si...
Rheumatic heart disease in the developing world: prevalence, prevention, and control

Rheumatic heart disease (RHD) continues to be a common health problem in the developing world, causing morbidity and mortality among both children and adults. Although little longitudinal data are available, evidence suggests that there has been little if any decline in the occurrence of RHD over the past few decades. Recent reports from the developing world have documented rheumatic fever (RF) incidence rates as high as 206/100,000 and RHD prevalence rates as high as 18.6/1000. The high frequency of RHD in the developing world necessitates aggressive prevention and control measures. The major interventions for prevention and control include: (1) reduction of exposure to group A streptococci, (2) primary prophylaxis to prevent initial episodes of RF, and (3) secondary prophylaxis to prevent recurrent episodes of RF. Because recurrent episodes of RF cause increasingly severe cardiac complications, secondary prophylaxis is the most crucial feature of an effective RHD programme. For some impoverished countries, secondary prophylaxis may be the only intervention that can realistically be implemented. In addition to this intervention, however, financial and human resources must be committed, and all of these elements must be integrated into existing primary health care systems. Because RHD continues to be a common health problem in the developing world, greater emphasis needs to be placed on the simple and cost-effective prevention and control measures that are currently available to combat this disabling disease.
Clinical findings and outcomes of ulcerative keratomycosis in 30 horses in the mid‐Atlantic United States (2006–2007)

Summary The purpose of this study was to determine the clinical course and outcome associated with keratomycosis in horses in the mid-Atlantic USA. Records of horses diagnosed with keratomycosis at New Bolton Center from November 2006 to November 2007 with positive fungal culture were retrospectively studied. Neither horses with ulcerative keratitis and a negative fungal culture nor those with stromal abscesses were included. Subject details, history, clinical findings, therapy and outcome were recorded. Thirty horses fitted both inclusion criteria (diagnosis of keratomycosis and positive corneal fungal culture). Fourteen of 30 cases occurred during summer. Aspergillus was the most commonly cultured fungal genus (17/30, or 57%) followed by Alternaria (4/30). Seventeen horses had positive bacterial and fungal cultures. Fifteen of 30 horses were treated surgically by a keratectomy and amnion (8) or conjunctival (7) graft. Itraconazole was the most common topical anti-fungal therapy and was utilised in 25/30 horses. Globe survival was 97% (29/30). All surviving globes had a positive menace response and were visual at the last examination. It was concluded that in the mid-Atlantic USA, fungal keratitis is common, has the highest incidence in summer, and is usually associated with a positive outcome. Aspergillus may be a relatively more common corneal pathogen in this region than elsewhere in the USA. Surgical cases were more likely to have fungal hyphae identified on cytology and tended to be hospitalised longer than medical cases. There was no apparent association between surgical disease and all other patient, organism and treatment variables.
Design and simulation of Fractional-N PLL frequency synthesizers

A fast simulation environment has been developed using MATLABM/spl trade/ and CMEX/spl trade/ for behavioral level simulation of Delta-Sigma (/spl Delta//spl Sigma/) based Fractional-N PLL frequency synthesizers. The simulator uses a differential equation approach with a uniform time step. To support a uniform time step in the simulation, the continuous-time average current-to-voltage loop filter transfer function is modeled as a discrete-time charge difference-to-voltage transfer function. Simulation results are presented on a type-II fourth-order PLL frequency synthesizer employing a third-order MASH /spl Delta//spl Sigma/ modulator.
Evidence for an indirect sympathetic control of atrial stretch receptor discharge in the dog.

Experiments were performed to determine the influence of cardiac sympathetic efferent nerve stimulation on the discharge rate of atrial type B stretch receptors in the anesthetized, open-chest dog. In all experiments, the left stellate ganglion was stimulated following volume expansion. To determine the effects of stellate stimulation, the responses of atrial receptors were observed during the withdrawal of blood in steps following intravascular volume expansion. Stimulation of the stellate ganglion decreased receptor discharge and left atrial pressure in all experiments. A change from a control left atrial pressure of 2.5 cm H2O (in peak left atrial v-wave pressure) resulted in a mean increase in receptor discharge of 6.6 ± 1.4 spikes/cardiac cycle during stellate stimulation; however, a change from a control pressure of 0.0 cm H2O resulted in a mean decrease in receptor discharge of 1.5 ± 1.5 spikes/cardiac cycle. The curves relating the change in atrial receptor discharge to the change in left atrial p...
pMatlab Parallel Matlab Library

MATLAB® has emerged as one of the languages most commonly used by scientists and engineers for technical computing, with approximately one million users worldwide. The primary benefits of MATLAB are reduced code development time via high levels of abstractions (e.g. first class multi-dimensional arrays and thousands of built in functions), interpretive, interactive programming, and powerful mathematical graphics. The compute intensive nature of technical computing means that many MATLAB users have codes that can significantly benefit from the increased performance offered by parallel computing. pMatlab provides this capability by implementing parallel global array semantics using standard operator overloading techniques. The core data structure in pMatlab is a distributed numerical array whose distribution onto multiple processors is specified with a "map" construct. Communication operations between distributed arrays are abstracted away from the user and pMatlab transparently supports redistribution between any block-cyclic-overlapped distributions up to four dimensions. pMatlab is built on top of the MatlabMPI communication library and runs on any combination of heterogeneous systems that support MATLAB, which includes Windows, Linux, MacOS X, and SunOS. This paper describes the overall design and architecture of the pMatlab implementation. Performance is validated by implementing the HPC Challenge benchmark suite and comparing pMatlab performance with the equivalent C+MPI codes. These results indicate that pMatlab can often achieve comparable performance to C+MPI, usually at one tenth the code size. Finally, we present implementation data collected from a sample of real pMatlab applications drawn from the approximately one hundred users at MIT Lincoln Laboratory. These data indicate that users are typically able to go from a serial code to an efficient pMatlab code in about 3 hours while changing less than 1% of their code.
Closed form approximations to the inverse black body radiation problem

The inverse black body radiation problem is the problem of determining the unknown area-temperature distribution of a black body from its radiated electromagnetic power spectrum. An exact iterative solution to this problem (the inverse Planck problem) was derived by this author in 1982. Recently Hamid and Ragheb derived a closed form approximation to this problem claimed to be valid for the Rayleigh-Jeans regime (the inverse Rayleigh-Jeans problems). It is shown that this Hamid-Ragheb solution is actually far superior to an inverse Rayleigh-Jeans approximation. A closed form approximation to the inverse black body radiation problem valid for the Wien regime (the inverse Wien problem) is presented, and shown to be equivalent to the leading term of the exact iterative solution of this author.
MERCURY INHIBITION ON PRIMARY PRODUCTIVITY USING LARGE VOLUME PLASTIC CHAMBERS IN SITU1

Approximately 6000 l of lake water was suspended in large, clear plastic chambers in Lake Powell, Arizona. The chambers were monitored during 24 h incubation periods in the spring and summer 1974 and 1975. Physico-chemical differences between the natural lake system and within the experimental chambers were negligible. Experimental mercury concentrations ranging from less than 0.02 to 1.25 ppM were added to the chambers to determine the effect of elevated Hg concentrations on in situ primary production. Mercury concentrations were monitored in the water column of each chamber during each 24 h incubation period to determine absolute concentrations following reduction through adsorption, absorption and vaporization. At least a 40 percent reduction in photosynthetic activity occurred at Hg concentrations as low as 0.06 ppM. A toxic Hg threshold concentration of 0.06 ppM was demonstrated for the summer phytoplankton assemblage, but a distinct threshold concentration was absent for the spring diatom assemblage. Differences in spring and summer phytoplankton populations may suggest subtle differences in Hg sensitivity between phytoplankton assemblages in combination with temperature acting on total community metabolism.
Rapid and potent induction of cell death and loss of NK cell cytotoxicity against oral tumors by F(ab')2 fragment of anti-CD16 antibody.

Freshly isolated untreated NK cells undergo rapid apoptosis and lose their cytotoxic function upon the addition of F(ab′)2 fragment of anti-CD16 antibodies. Loss of NK cell cytotoxic function after treatment with F(ab′)2 fragment of anti-CD16 antibody can be seen against K562 and UCLA-2 oral tumor cells when either added immediately in the co-cultures of NK cells with the tumor cells or after pre-treatment of NK cells with the antibody before their addition to the tumor cells. Addition of Interleukin-2 (IL-2) in combination with anti-CD16 antibody to NK cells delayed the induction of DNA fragmentation in NK cells, and even though decreased cytotoxicity could still be observed against K562 and UCLA-2 oral tumors when compared to IL-2 alone treated NK cells, the cytotoxicity levels remained relatively higher and approached those obtained by untreated NK cells in the absence of antibody treatment. No increases in IFN-γ, Granzymes A and B, Perforin and TRAIL genes could be seen in NK cells treated with anti-CD16 antibody. Neither secretion of IFN-γ nor increased expression of CD69 activation antigen could be observed after the treatment of NK cells with anti-CD16 antibody. Furthermore, IL-2 mediated increase in CD69 surface antigens was down-modulated by anti-CD16 antibody. Finally, the addition of anti-CD16 antibody to co-cultures of NK cells with tumor target cells was not inhibitory for the secretion of VEGF by oral tumor cells, unlike those co-cultured with untreated or IL-2 treated NK cells. Thus, binding and triggering of CD16 receptor on NK cells may enhance oral tumor survival and growth by decreased ability of NK cells to suppress VEGF secretion or induce tumor cell death during the interaction of NK cells with oral tumor cells.
A trajectory equation for walking droplets : hydrodynamic pilot-wave theory

We present the results of a theoretical investigation of droplets bouncing on a vertically vibrating fluid bath. An integro-differential equation describing the horizontal motion of the drop is developed by approximating the drop as a continuous moving source of standing waves. Our model indicates that, as the forcing acceleration is increased, the bouncing state destabilizes into steady horizontal motion along a straight line, a walking state, via a supercritical pitchfork bifurcation. Predictions for the dependence of the walking threshold and drop speed on the system parameters compare favourably with experimental data. By considering the stability of the walking state, we show that the drop is stable to perturbations in the direction of motion and neutrally stable to lateral perturbations. This result lends insight into the possibility of chaotic dynamics emerging when droplets walk in complex geometries.
Aircraft Design Simulation Verification and Testing

This paper describes the procedure for validating the Aircraft Design Simulation (ADS), a modular software tool designed to be used in the development of a new aircraft by rapidly simulating its behavior. The purpose of the ADS project was to introduce undergraduate students to modeling and simulation techniques, as well as software verification and testing procedures. The ADS tool suite was developed by undergraduate students, with the supervision of a faculty advisor, at Embry-Riddle Aeronautical University to be used in design courses and student projects. Prior to using any new tool, it is important to verify that the tool is functioning properly. The ADS tool is capable of three primary functions: Trim, Linearization, and Simulation. Each of these functions has been checked to verify that they perform properly.
When Agencies Go Nuclear: A Game Theoretical Approach to the Biggest Sticks in an Agency’s Arsenal

A regulatory agency’s arsenal often contains multiple weapons. Occasionally, however, an agency has the power to completely obliterate its regulatory targets or to make major waves in society by using a “regulatory nuke.” A regulatory nuke is a tool with two primary characteristics. First, it packs power sufficient to profoundly impact individual regulatory targets or significantly affect important aspects of society or the economy. Second, from the perspective of the regulatory agency, it is politically unavailable in all but the most extreme situations. They are found in many corners of the federal bureaucracy. This Article illustrates that even when individual regulatory nukes get our attention, we often think about these weapons in unproductive ways. Typically, regulatory nukes are approached in a bipolar way. On the one hand, they may be seen as regulatory anomalies with little relevance to most regulated entities. On the other hand, particularly if an agency has launched its regulatory nuke, the launch becomes part of agency lore and the story is of the destruction left in its wake.Drawing on the Nobel Prize–winning game theory developed by Thomas Schelling, this Article moves beyond the dud/mushroom cloud dichotomy and recasts the regulatory nuke as an important factor that influences the calculus of regulation. This analysis suggests that agencies often get mileage out of regulatory nukes by pointing their weapons rather than firing them: the power of the tool is often leverage in regulatory diplomacy — for threats, posturing, and coercion. Although this Article is based on game theory, it also provides a wealth of examples that work to illustrate the real-world importance of the theory to many aspects of the administrative state..
Exploiting hierarchy in parallel computer networks to optimize collective operation performance

The efficient implementation of collective communication operations has received much attention. Initial efforts modeled network communication and produced "optimal" trees based on those models. However, the models used by these initial efforts assumed equal point-to-point latencies between any two processes. This assumption is violated in heterogeneous systems such as clusters of SMPs and wide-area "computational grids", and as a result, collective operations that utilize the trees generated by these models perform suboptimally. In response, more recent work has focused on creating topology-aware trees for collective operations that minimize communication across slower channels (e.g., a wide-area network). While these efforts have significant communication benefits, they all limit their view of the network to only two layers. We present a strategy based upon a multilayer view of the network. By creating multilevel topology trees we take advantage of communication cost differences at every level in the network. We used this strategy to implement topology-aware versions of several MPI collective operations in MPICH-G, the Globus-enabled version of the popular MPICH implementation of the MPI standard. Using information about topology discovered by Globus, we construct these topology-aware trees automatically during execution, thus freeing the MPI application programmer from having to write special files or functions to describe the topology to the MPICH library. We present results demonstrating the advantages of our multilevel approach by comparing it to the default (topology-unaware) implementation provided by MPICH and a topology-aware two-layer implementation.
Encoding of eye position in the goldfish horizontal oculomotor neural integrator.

Monocular organization of the goldfish horizontal neural integrator was studied during spontaneous scanning saccadic and fixation behaviors. Analysis of neuronal firing rates revealed a population ...
Which Prepared-Childbirth Coping Strategies Are Effective?

To investigate coping strategies taught in childbirth education classes, a study was conducted of nulliparous women immersing their hands in ice water. Length of tolerance and self-reported pain served as measures of the techniques' effectiveness. Results in Experiment 1 showed structured breathing to be more effective than normal breathing. Effleurage was less helpful than no effleurage. Practice under stress was better than either imaginal practice or no practice. In Experiment 2 a combination of structured breathing and attention focal points was much better than normal breathing. While coaching was better than no coaching, the combination of structured breathing, attention focal points, and coaching produced the strongest treatment.
Normalized Entropy Vectors, Network Information Theory and Convex Optimization

We introduce the notion of normalized entropic vectors-slightly different from the standard definition in the literature in that we normalize entropy by the logarithm of the alphabet size. We argue that this definition is more natural for determining the capacity region of networks and, in particular, that it smooths out the irregularities of the space of non-normalized entropy vectors and renders the closure of the resulting space convex (and compact). Furthermore, the closure of the space remains convex even under constraints imposed by memoryless channels internal to the network. It therefore follows that, for a large class of acyclic memoryless networks, the capacity region for an arbitrary set of sources and destinations can be found by maximization of a linear function over the convex set of channel-constrained normalized entropic vectors and some linear constraints. While this may not necessarily make the problem simpler, it certainly circumvents the "infinite-letter characterization" issue, as well as the nonconvexity of earlier formulations, and exposes the core of the problem. We show that the approach allows one to obtain the classical cutset bounds via a duality argument. Furthermore, the approach readily shows that, for acyclic memoryless wired networks, one need only consider the space of unconstrained normalized entropic vectors, thus separating channel and network coding - a result very recently recognized in the literature.
A rapidly reversible degenerate cope rearrangement

Abstract The occurrence of a structurally degenerate Cope rearrangement which proceeds rapidly at room temperature is revealed by the examination, at varying temperatures, of the N.M.R. spectrum of bicyclo[5.1.0]octa-2,5-diene (I). This molecule is made by the cyclopropanation of cycloheptatriene in the 3, 4 position according to Gaspar-Roth. Its structure is assigned by virtue of its conversion to bicyclo[5.1.0]octane on catalytic hydrogenation and its failure to absorb U.V. light at λ > 210 mμ. At 225°, its double-bond isomer, bicyclo[5.1.0]octa-2,4-diene (II), rearranges to cycloocta-1,3,5-triene which is subsequently transformed to benzene (and ethylene ?) and a substance tentatively assigned the structure, tricyclo[3.2.1.02,7]oct-3-ene(III). This latter material appears to arise from and be in equilibrium with 5-vinylcyclohexa-1,3-diene (IV) through the relationship of an intramolecular Diels-Alder reaction. The hypothetical tricyclo[3.3.2.04,6]deca-2,7,9-triene (VII) is a uniquely interesting molecule in which individual carbon atoms must circulate freely about the structure quite independently of each other if the Cope rearrangement operates.
Matrix Analysis of Oriented Graphs with Irreducible Feedback Loops

A generating function is obtained for the nonrepetitive closed loops of a network with unidirectional elements; from this is derived an analogous function for the irreducible loops. Criteria for the existence of loops are then established and the size of the smallest loop present determined; an asymptotic evaluation is made of the number of irreducible loops in a completely connected network. Further application of the generating function permits estimation of bounds for both irreducible and composite closed loops of a given order; less rigorous bounds are found by two perturbation techniques. The generating function is reformulated in terms of determinant-like quantities and application made to small networks. Transformations preserving the irreducible loops of a system are discussed at length, following a delineation of the meaning of loop equivalence. Methods employed include elimination of branches, condensation of nodes, and decomposition of circuits, with criteria for their utilization being set forth. Finally, connection is made between the analysis of the present paper and those prevalent in more avowedly topological treatments.
Drop-Landing Performance and Knee-Extension Strength After Anterior Cruciate Ligament Reconstruction

Context: Individuals with a history of anterior cruciate ligament reconstruction (ACLR) are at greater risk of reinjury and developing early-onset osteoarthritis due to persistent abnormal joint loading. Real-time clinical assessment tools may help identify patients experiencing abnormal movement patterns after ACLR. Objective: To compare performance on the Landing Error Scoring System (LESS) between participants with ACLR and uninjured control participants and to determine the relationship between LESS score and knee-extension strength in these participants. Design: Controlled laboratory study. Setting: Research laboratory. Patients or Other Participants: Forty-six recreationally active participants, consisting of 22 with ACLR (12 men, 10 women; age = 22.5 ± 5.0 years, height = 172.8 ± 7.2 cm, mass = 74.2 ± 15.6 kg, body mass index = 24.6 ± 4.0) and 24 healthy control participants (12 men, 12 women; age = 21.7 ± 3.6 years, height = 168.0 ± 8.8 cm, mass = 69.2 ± 13.6 kg, body mass index = 24.3 ± 3.2) were...
Leptin concentrations in finishing beef steers and heifers and their association with dry matter intake, average daily gain, feed efficiency, and body composition

The objective of this experiment was to determine the association of circulating plasma leptin concentrations with production and body composition measures of finishing beef steers and heifers and to determine if multiple sampling time points improve the associations of plasma leptin concentrations with production and body composition traits. Individual dry matter intake (DMI) and ADG were determined for 84 d using steers and heifers (n = 127 steers and n = 109 heifers). Blood was collected on day 0, day 42, and day 83 for determination of plasma leptin concentrations. Leptin concentrations were greater in heifers than those in steers on day 0 (P < 0.001 for sex by day interaction), and leptin concentrations increased in both sexes but were not different from each other on day 83. Leptin concentrations at all 3 time points and the mean were shown to be positively associated with DMI (P ≤ 0.006), whereas the mean leptin concentration explaining 8.3% of the variance of DMI. Concentrations of leptin at day 42, day 83, and the mean of all 3 time points were positively associated with ADG (P ≤ 0.011). Mean leptin concentration was negatively associated with gain:feed ratio and positively associated with residual feed intake (RFI), indicating that more efficient cattle had lower leptin concentrations. However, leptin concentrations explained very little of the variation in residual feed intake (≤ 3.2% of the variance). Leptin concentrations were positively associated with body fat measured by ultrasonography at the 12th rib and over the rump (P < 0.001), with the mean leptin concentration explaining 21.9% and 12.7% of the variance in 12th rib and rump fat thickness, respectively. The same trend was observed with carcass composition where leptin concentrations were positively associated with 12th rib fat thickness, USDA-calculated yield grade (YG), and marbling score (P ≤ 0.006) and mean leptin concentration explained 16.8, 18.2, and 4.6% of the variance for 12th rib fat thickness, yield grade, and marbling score, respectively. Given these and previous results, it appears that leptin physiology could be a candidate for mechanisms that contribute to feed intake and feed efficiency variation in beef cattle.