cssi/SciSciGPT-SciSciNet huggingface dataset:
Assessing the role of interseeding alfalfa into grass on improving pasture soil health in semi-arid Texas High Plains

Abstract The rapid decline in water supply for irrigation in the Texas High Plains is encouraging some growers to convert their irrigated cropland to production of drought-tolerant forages such as ‘WW-B.Dahl’ cultivar of Old World bluestem [OWB, Bothriochloa bladhii (Retz) S.T. Blake]. This perennial, warm-season pasture grass protects the soil surface from erosion; however, it needs nitrogenous fertilizer from an external source or by interseeding a nitrogen (N)-fixing legume to maximize productivity and quality of the pasture. Alfalfa (Medicago sativa L.) is a relatively drought-tolerant and high quality forage legume which is compatible with perennial grasses and enhances dietary protein supply for grazing cattle and improves pasture soil health. The aim of this study was to assess the value of interseeding alfalfa into established OWB grass on improving pasture soil health in relation to OWB grown in a monoculture stand. We investigated the microbial and chemical properties of soil taken at 0–10 cm in March of 2019 from OWB and OWB-alfalfa as a preliminary information for understanding the potential role of alfalfa on improving soil health. At this early assessment of the introduction of alfalfa into OWB, soil microbial biomass carbon (MBC) and nitrogen (MBN) were greater (P
Unsupervised Machine Learning of Quantum Phase Transitions Using Diffusion Maps

Experimental quantum simulators have become large and complex enough that discovering new physics from the huge amount of measurement data can be quite challenging, especially when little theoretical understanding of the simulated model is available. Unsupervised machine learning methods are particularly promising in overcoming this challenge. For the specific task of learning quantum phase transitions, unsupervised machine learning methods have primarily been developed for phase transitions characterized by simple order parameters, typically linear in the measured observables. However, such methods often fail for more complicated phase transitions, such as those involving incommensurate phases, valence-bond solids, topological order, and many-body localization. We show that the diffusion map method, which performs nonlinear dimensionality reduction and spectral clustering of the measurement data, has significant potential for learning such complex phase transitions unsupervised. This method may work for measurements of local observables in a single basis and is thus readily applicable to many experimental quantum simulators as a versatile tool for learning various quantum phases and phase transitions.
Inhibition of the Spectraplakin Protein Microtubule Actin Crosslinking Factor 1 Sensitizes Glioblastomas to Radiation

Background Microtubule actin crosslinking factor 1 (MACF1) is a spectraplakin cytoskeletal crosslinking protein whose function and role in cancer biology has lacked investigation. Recent studies have identified MACF1 as a novel target in glioblastomas expressed in tissue from tumor patient explants but not normal brain tissue and when silenced has an antitumorigenic impact on these tumors. Radiation as a single agent therapy to treat glioblastomas has been used for decades and has done little to improve survival of individuals diagnosed with this disease. However, contemporary clinical radiotherapy protocols have provided evidence that combinatorial radiotherapy approaches confer a therapeutic benefit in glioblastoma patients. In this study MACF1 was investigated as a radiosensitization target in glioblastomas. Methods To provide context of MACF1 in glioblastomas, The Cancer Genome Atlas expression analyses were performed in conjunction with genes associated with glioblastoma evolution, while a genetic inhibitory approach, cell migratory assays, and immunofluorescence procedures were used to evaluate responses to MACF1 suppression with radiation. Additionally, expression analyses were conducted to assess co-expression of mTOR signaling pathway regulators and MACF1 in glioblastoma patient samples. Results Our amalgamation approach demonstrated that negative regulation of MACF1, which was positively correlated with epidermal growth factor receptor and p70s6k expression, enhanced the sensitivity of glioblastoma cells to radiation as a consequence of reducing glioblastoma cell viability and migration. Mechanistically, the antitumorigenic effects on glioblastoma cell behaviors after radiation and impairing MACF1 function were associated with decreased expression of ribosomal protein S6, a downstream effector of p70s6k. Conclusion MACF1 represents a diagnostic marker with target specificity in glioblastomas that can enhance the efficacy of radiation while minimizing normal tissue toxicity. This approach could potentially expand combinatorial radiation strategies for glioblastoma treatments via impairment of translational regulatory processes that contribute to poor patient survival.
A retrospective comparison of carbon dioxide surgical laser and non-laser excision for removal of cutaneous and subcutaneous soft-tissue sarcomas in dogs.

Aims: To compare the duration of anaesthesia, surgery, and postoperative hospitalisation, the proportion of tumours excised with complete histologic margins and immediate postoperative surgical sit...
The Information that is Combined Across Fixations may be Different for Static and Moving Objects

A large body of literature in reading indicates that “visual” information extracted from an eye fixation is not used to help encoding text on subsequent fixations. Moreover, similar experiments in object recognition and experiments in detecting changes in static scenes both indicate that little visual information is used even with non-symbolic stimuli. In contrast, experiments dealing with the perception of both simple rotary and complex biological motion indicate that quite accurate visual information must be maintained across fixations. This suggests that there may be a fundamentally different way in which motion and static information are retained and integrated across fixations.
An Experimental-XANES Investigation of Cr Valence Systematics in Basaltic Liquids and Applications to Modeling Cr2+/ Σ Cr Evolution in Crystallizing Basaltic Magma Systems

Abstract Harvesting quantitative fO2 information from synchrotron μ-XANES measurements of Cr2+/ΣCr in olivine phenocrysts requires robust thermodynamic or empirical models that can accurately predict Cr2+/ΣCr in basaltic liquids as a function of fO2, temperature, and liquid chemistry. We present the results from a combined experimental-XANES study designed to illuminate how evolving liquid chemistry and decreasing temperature influence the equilibrium Cr2+/ΣCr ratios in crystallizing basaltic liquids. The Cr valence dataset produced from these experiments was fit with a symmetric regular solution model; this fitting generated a model equation that predicts the Cr2+/ΣCr in basaltic magmas. Using MELTS in conjunction with the newly calibrated Cr valence model, we calculated the Cr2+/ΣCr of a tholeiitic liquid undergoing isobaric equilibrium crystallization at 2.5 °C intervals. The modeling results indicate that Cr2+/ΣCr evolves dynamically in crystallizing liquids composition and may be partially decoupled from bona fide changes in magmatic fO2. These calculations suggest that the increasing iron content of the residual liquid is the most influential factor influencing the Cr2+/ΣCr of the residual liquid. Olivine normative tholeiitic liquids following a liquid line of descent parallel to an oxygen fugacity buffer curve experience significant decreases in the equilibrium Cr2+/ΣCr of their residual liquids. Our modeling also demonstrates that Cr2+/ΣCr values preserved in early olivine phenocrysts indeed reflect the magmatic fO2 conditions under which they grew; however, the effects of magmatic fO2 are also superimposed on the underlying influences of temperature and melt chemistry.
The Spike-specific IgA in milk commonly-elicited after SARS-Cov-2 infection is concurrent with a robust secretory antibody response, exhibits neutralization potency strongly correlated with IgA binding, and is highly durable over time

Approximately 10% of infants will experience COVID-19 illness requiring advanced care (1). A potential mechanism to protect this population could be provided by passive immunity through the milk of a previously infected mother. We and others have reported on the presence of SARS-CoV-2-specific antibodies in human milk (2-5). We now report the prevalence of SARS-CoV-2 IgA in the milk of 75 COVID-19-recovered participants, and find that 88% of samples are positive for Spike-specific IgA. In a subset of these samples, 95% exhibited robust IgA activity as determined by endpoint binding titer, with 50% considered high-titer. These IgA positive specimens were also positive for Spike-specific antibodies bearing the secretory component. Levels of IgA antibodies and antibodies bearing secretory component were shown to be strongly positively correlated. The secretory IgA response was dominant among the milk samples tested compared to the IgG response, which was present in 75% of samples and found to be of high-titer in only 13% of cases. Our IgA durability analysis using 28 paired samples, obtained 4-6 weeks and 4-10 months after infection, found that all samples exhibited persistently significant Spike-specific IgA, with 43% of donors exhibiting increasing IgA titers over time. Finally, COVID-19 and pre-pandemic control milk samples were tested for the presence of neutralizing antibodies; 6 of 8 COVID-19 samples exhibited neutralization of Spike-pseudotyped VSV (IC50 range, 2.39 - 89.4ug/mL) compared to 1 of 8 controls. IgA binding and neutralization capacities were found to be strongly positively correlated. These data are highly relevant to public health, not only in terms of the protective capacity of these antibodies for breastfed infants, but also for the potential use of such antibodies as a COVID-19 therapeutic, given that secretory IgA is highly stable not only in milk and the infant mouth and gut, but in all mucosa including the gastrointestinal tract, upper airway, and lungs (6).
A Cadaveric and Magnetic Resonance Imaging Investigation of the Salpingopharyngeus.

Purpose The aim of the study was to update our information regarding the salpingopharyngeus (SP) muscle using cadaveric and in vivo magnetic resonance imaging (MRI) data. Primary objectives were to...
Monitoring by Auditors: Case of Public Housing Authorities

We take advantage of the unique reporting requirements of nonprofit public housing authorities (PHAs) to study the effect of audits on financial information both generally and when there are management incentives to misreport financial data. There is little prior research on the effect of audit adjustments in nonprofit settings and conflicting research on how auditors react to management’s incentives to misreport. We identify potential financial statement areas at risk of manipulation based on incentives specific to public housing authorities. Using pre- and post-audit financial data for almost 3,600 PHAs across seven years, we find that auditors make economically and statistically significant adjustments to PHA financial statements. In addition, we find evidence that audits appear to reduce potential management bias, particularly to reduce risks of overstatement. Overall, audits appear to matter in this nonprofit, low-litigation risk setting where there is a large concentration of non-Big 4 auditors.
Determination of the Radial Profile of the Beam Current Density in Emittance Dominated Beams for High Frequency TWTS

High frequency tubes are limited on their power handling capabilities due to their very small beam size. Typically, the beam cross section is chosen as half of the minimum width of the tube cross section i.e. the beam size scales down linearly as the frequency goes higher. In addition, velocity spread is very prominent in small cross section beams and, as such, beams are mostly dominated by emittance. One of the biggest challenges for high frequency tubes is to determine the maximum allowable beam size without significant current interception. This will enable the tube to operate with the greatest possible beam power and thus have both the largest gain and output power possible. Therefore, we propose to determine the intercepted beam current in an emittance dominated beam for high frequency tubes. Our objective is to provide the tools needed to determine beam pipe sizes for arbitrary levels of beam emittance and beam current interception rates.
A Maximum Power Algorithm to Find Frequencies for Aperiodic Clock Testing

The total logic activity produced in a digital circuit during testing, and hence the total energy consumed, is an invariant of a set of tests. Faster we consume this energy, shorter will the test time be. Thus, to minimize the test time we may maximize the power during test by using a dynamically selectable clock frequency. This idea is exploited in our solution for the problem of finding clock frequencies under the constraints of maximum allowable power and critical path delay. A very efficient but approximate kth-root solution finds k test clock frequencies, which are further optimized by a locally exhaustive search (LES) algorithm. Both solutions have an O(N×k) complexity for finding k clock frequencies when the test runs through N clock cycles, though kth-root solution is about two orders of magnitude faster to compute than LES. In practice, LES gives optimally minimum test time and is matched by the kth-root solution for k ? 10.
Latent Structure and Causal Variables

This article is reproduced from the previous edition, volume 12, pp. 8395–8400, © 2001, Elsevier Ltd. with an updated Bibliography section supplied by the Editor.
Study II: Intervention Process and Outcome Results

The results from Study I confirmed that the intervention model of behavioral contracting and child advocacy reduced officially recorded delinquent behavior to a greater extent than treatment-as-usual by a juvenile court. The major purpose of Study II was to examine the generalizability of this treatment by varying volunteer types to include community college students (CCV) and individuals from the community at large (CV), as well as university student volunteers (UV). Although other intervention models were effective in reducing delinquent behavior, the Action model received the highest satisfaction ratings from the volunteers. For this reason, the Action model was the one selected for implementation in Study II. Thus Study II involved the experimental comparison of three different types of nonprofessional volunteers implementing the Action model with treatment-as-usual by a juvenile court. As with Study I, the control comparison was a group of randomly assigned juveniles who had been petitioned to the juvenile court. Once randomization had been completed, these juveniles were returned to the court staff for treatment-as-usual. Once again, the process results are important for understanding the context of the outcome findings. Therefore, each set of analyses is presented in this order.
What Did You Mean by That? Misunderstanding, Negotiation, and Syntactic Semantics

Syntactic semantics is a holistic, conceptual-role-semantic theory of how computers can think. But Fodor and Lepore have mounted a sustained attack on holistic semantic theories. However, their major problem with holism (that, if holism is true, then no two people can understand each other) can be fixed by means of negotiating meanings. Syntactic semantics and Fodor and Lepore's objections to holism are outlined; the nature of communication, miscommunication, and negotiation is discussed; Bruner's ideas about the negotiation of meaning are explored; and some observations on a problem for knowledge representation in AI raised by Winston are presented.
Conversion of the proximal histidine ligand to glutamine restores activity to an inactive mutant of cytochrome c peroxidase.

Abstract Using site-directed mutagenesis, a double mutant in yeast cytochrome c peroxidase (CCP) has been constructed where the proximal ligand, His175, has been converted to glutamine and the neighboring Trp191 has been converted to phenylalanine. The refined 2.4-A crystal structure of the double mutant shows that the Gln175 side chain is within coordination distance of the heme iron atom and that Phe191 occupies the same position as Trp191 in the native enzyme with very little rearrangement outside the immediate vicinity of the mutations. Consistent with earlier work, we find that the single mutant, His175-->Gln, is fully active under steady state assay conditions and that as reported earlier (Mauro et al., 1988), the Trp191-->Phe mutant exhibits only Gln/Phe191-->Phe, exhibits 20% wild type activity. Since it is known that the Trp191-->Phe mutant is inactive because it can no longer transfer electrons from ferrocytochrome c, changing the nature of the proximal ligand is able to restore this activity. These results raise interesting questions regarding the mechanism of interprotein electron transfer reactions.
Influence of Dietary Selenium on Lead Toxicity in the Rat

An investigation of the influence of dietary selenium (0.015, 0.05, 0.50, 1.0 ppm) on toxicity of dietary lead (0 and 200 ppm) in the young male rat indicated that selenium was mildly protective against the toxic effects of lead, but only up to 0.50 ppm selenium. At the excess selenium dietary level an exaggeration of lead toxicity was observed. Criteria employed to judge the effects of dietary selenium on lead toxicity included tissue lead concentration and urinary delta-aminolevulinic acid excretion. One exception to the exaggeration effect of excess selenium on lead toxicity was the protective effect of selenium on liver delta-aminolevulinic acid dehydratase activity. Since lead depressed kidney selenium concentration, lead may act as an antagonist to selenium metabolism.
Advance directives in mental health care: evidence, challenges and promise.

Psychiatric advance directives (PADs) are written documents or oral statements that allow adults with decision-making capacity to declare their treatment preferences and/or to designate proxy decision makers to act on their behalf should they be deemed incapable in the future of making informed choices on their own. In the U.S., the Patient Self-Determination Act (1) created momentum for recovery-oriented care, which has led to the enactment of mental health-related advance planning legislation in about two-thirds of the states (2,3). Internationally, increasing attention to such tools is found in the U.K., Ireland, Germany, Belgium, Canada, New Zealand, Australia and India.
Lipid Composition of a Psychrophilic Marine Vibrio sp. During Starvation-Induced Morphogenesis.

Qualitative and quantitative changes with time in phospholipids and fatty acids were examined after suspension of cells of a psychrophilic marine bacterium in nutrient-free artificial seawater at 5°C. Viability was maintained throughout the 21-day examination period, with plate counts and acridine orange direct counts indicating a slight increase in cell number. Gravimetric data, however, showed a significant decrease in bacterial biomass during the 3-week study. Levels of ATP per cell also decreased significantly (59%) during the starvation period. Since starvation (resulting in dormancy) is probably the typical physiological state of marine bacteria, estimation of bacterial density in marine waters by using ATP data obtained from log-phase cells is probably inaccurate. Total lipid phosphate decreased (65%) during the starvation period, with phosphatidylethanolamine showing the greatest loss. A large increase (57%) in the neutral lipid fraction was also detected, especially during the first week of starvation. A selective increase in palmitoleate at the expense of myristate was detected in the membrane lipids. The effects of these changes on membrane fluidity and the possible consequences for these cells in the marine environment are discussed.
Understanding Disputes: The Politics of Argument

Understanding Disputes: The Politics of Argument. Pat Caplan. ed. Oxford, England: Berg Publishers, 1995. 248 pp.
Improving Adhesion of Seasonings to Crackers with Hydrocolloid Solutions

Food powders were applied on crackers that had been coated using water, oil, emulsion, sucrose, or hydrocolloid solutions. The hydrocolloids that were used include gellan gum, kappa-carrageenan, methylcellulose, gum karaya, gum tragacanth, gum arabic, guar gum, modified starch, and maltodextrin. Solutions of similar hydrophobicity to the powder gave the greatest adhesion. NaCl, barbecue (BBQ), ranch, and sour cream & onion (SC&O) seasoning showed greatest adhesion with water, cheese powder with an emulsion of 12.5% to 25% oil, and cocoa powder with oil. For NaCl, BBQ, ranch, and SC&O seasoning, hydrocolloids improved the adhesion over using water alone, with gellan gum providing the greatest adhesion. Hydrocolloid structural differences, including the presence or absence of branching, substitution of sugar units, and molecular weight affect water binding and thickening of the hydrocolloid spray that seemed to be significant factors affecting adhesion of powders to the target surface. For cheese powder, hydrocolloids were capable of replacing the oil within an emulsion while improving or maintaining the same level of adhesion, with gum arabic providing the greatest adhesion. For cocoa powder, hydrocolloid solutions were ineffective adhesives due to differences in hydrophilicity that result in insolubility. The effect of hydrocolloid concentration on adhesion was dependent both on the hydrocolloid type and the concentration that is sprayable, with 0.5% being the optimum concentration for most gums. Adhesion using sucrose solutions was determined by particle size and relative hydrophobicity. Increasing sucrose concentration decreased adhesion of smaller particles, but increased adhesion of larger particles. Adhesion of NaCl significantly increased with decreasing NaCl size using oil, water, and sucrose solutions.
Potential utility of electronic drug compliance monitoring in measures of adverse outcomes associated with immunosuppressive agents

Poor compliance with prescribed medications limits the effectiveness of many pharmacologic therapies and enhances their potential toxicities. Traditional methods of measuring drug-taking behavior, including direct observation, patient self-report, pill counts, and therapeutic drug level monitoring, all have well-described limitations in validity and interpretability. Electronic medication event monitoring has been used to assess compliance with therapies for hypertension, glaucoma, anemia, and epilepsy, overcoming many problems of traditional approaches. However, no published reports describe the use of electronic monitoring with immunosuppressive agents, despite their increasing use for non-life-threatening conditions and their many dose-dependent toxicities. Transplant recipients are thought to be at particular risk from noncompliance. Therefore, we undertook this study to assess the feasibility of electronically monitoring compliance with immunosuppressive drugs among renal allograft recipients. Twenty-five kidney transplant patients receiving immunosuppressive medications from a single pharmacy were enrolled. Each subject received electronic monitors with their immunosuppressive serum drug refills for cyclosporine and azathioprine. Each subject returned their monitors after the first month of this 2-month study for downloading data. The frequency distribution of interdose intervals were described. Two measures of average non-compliance were calculated for both drugs: the proportion of monitored days that had missed doses, and the proportion of missed doses. Once daily and twice daily regimens of cyclosporine were compared. Concordance in drug compliance between the two drugs was calculated for each subject and averaged over the study population. Twenty-two of 25 subjects missed one or more doses of cyclosporine or azathioprine. Seventeen (68%) subjects never missed four or more consecutive doses. Subjects were non-compliant with cyclosporine on 8.7% of monitored days, and non-compliance with azathioprine on 9.8% of monitored days. Subjects were non-compliant with 6.8% of their cyclosporine doses and 9.8% of their azathioprine doses. Patients were compliant with both drugs on 86.6% of days and were non-compliant with both drugs on 5.1% of days. Subjects were non-compliant with cyclosporine during 5% and 13.2% of monitored days for once and twice daily dosing regimens, respectively. Concordance analysis demonstrated that for 91.7% of days of monitoring, compliance information was identical for both drugs. This study demonstrated the feasibility of electronic medication event monitoring among kidney transplant patients. This methodology represents an important tool for monitoring compliance of immunosuppressive agents essential to their safe and effective use, and should be considered for use in future studies of these drugs and others with substantial dose-dependent toxicity. Copyright © 1999 John Wiley & Sons, Ltd.
Kronecker product permutation matrices and their application to moment matrices of the normal distribution

In this paper, we consider the matrix which transforms a Kronecker product of vectors into the average of all vectors obtained by permuting the vectors involved in the Kronecker product. An explicit expression is given for this matrix, and some of its properties are derived. It is shown that this matrix is particularly useful in obtaining compact expressions for the moment matrices of the normal distribution. The utility of these expressions is illustrated through some examples.
Structural Determinants of Occupational Mobility in a Regional Labor Market

The purpose of this paper is to identify structural determinants of intraregional occupational mobility. This is done by developing a Markov chain model of job-vacancy transfers, disaggregating that model into its constituent parts, and identifying each part with a unique structural determinant. The disaggregated Markov model yields probabilities of mobility among occupational sectors for specific subgroups of mobile workers. To clarify ideas, a numerical illustration is developed. It is based on US census data and deals with occupational mobility among male and female members of the work force in the State of Utah.
Cannulation techniques: Biliary and pancreatic

Optimal performance of endoscopic retrograde cholangiopancreatography requires facility with side-viewing endoscopes and consistent cannulation of the desired duct. Skilled biliary specialists achieve successful cannulation 95% to 99% of the time while experienced community endoscopists should reach cannulation rates above 90%. To achieve these cannulation rates, endoscopists must be prepared to adapt to all varieties of periampullary anatomy and pathology. Neither a rigidly defined sequence of accessories nor a progressively random attack on the papilla will maximize cannulation success, although complications may increase with these arbitrary approaches. Difficult access can usually be overcome by using basic anatomic principles to optimize endoscope position and cannula axis, and by selecting accessories based upon identified challenges. This article reviews manipulation of the visual field within the duodenum, means to optimal axes for cannulation, commonly encountered difficulties in achieving biliary access, alternative approaches to biliary access when standard cannulation is difficult, cannulation of the major and minor pancreatic ducts, and cannulation in patients with surgically altered anatomy.
SNIF TOOL: sniffing for patterns in continuous streams

Continuous time-series sequence matching, specifically, matching a numeric live stream against a set of redefined pattern sequences, is critical for domains ranging from fire spread tracking to network traffic monitoring. While several algorithms exist for similarity matching of static time-series data, matching continuous data poses new, largely unsolved challenges including online real-time processing requirements and system resource limitations for handling infinite streams. In this work, we propose a novel live stream matching framework, called n-Snippet Indices Framework (in short, SNIF), to tackle these challenges. SNIF employs snippets as the basic unit for matching streaming time-series. The insight is to perform the matching at two levels of granularity: bag matching of subsets of snippets of the live stream against prefixes of the patterns, and order checking for maintaining successive candidate snippet bag matches. We design a two-level index structure, called SNIF index, which supports these two modes of matching. We propose a family of online two-level prefix matching algorithms that trade off between result accuracy and response time. The effectiveness of SNIF to detect patterns has been thoroughly tested through experiments using real datasets from the domains of fire monitoring and sensor motes. In this paper, we also present a study of SNIF's performance, accuracy and tolerance to noise compared against those of the state-of-the-art Continuous Query with Prediction (CQP) approach.
Bacterial contact-dependent growth inhibition.

Bacteria cooperate to form multicellular communities and compete against one another for environmental resources. Here, we review recent advances in the understanding of bacterial competition mediated by contact-dependent growth inhibition (CDI) systems. Different CDI + bacteria deploy a variety of toxins to inhibit neighboring cells and protect themselves from autoinhibition by producing specific immunity proteins. The genes encoding CDI toxin–immunity protein pairs appear to be exchanged between cdi loci and are often associated with other toxin-delivery systems in diverse bacterial species. CDI also appears to facilitate cooperative behavior between kin, suggesting that these systems may have other roles beyond competition.
Twists in Catalysis: Alternating Conformations of Escherichia coli Thioredoxin Reductase

In thioredoxin reductase (TrxR) from Escherichia coli, cycles of reduction and reoxidation of the flavin adenine dinucleotide (FAD) cofactor depend on rate-limiting rearrangements of the FAD and NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) domains. We describe the structure of the flavin-reducing conformation of E. coli TrxR at a resolution of 3.0 angstroms. The orientation of the two domains permits reduction of FAD by NADPH and oxidation of the enzyme dithiol by the protein substrate, thioredoxin. The alternate conformation, described by Kuriyan and co-workers, permits internal transfer of reducing equivalents from reduced FAD to the active-site disulfide. Comparison of these structures demonstrates that switching between the two conformations involves a "ball-and-socket" motion in which the pyridine nucleotide-binding domain rotates by 67 degrees.
Transfer-function synthesis with computer amplifiers and passive networks

The study of dynamic systems on an analog computer often involves the synthesis of complex transfer functions. Techniques from the field of network synthesis are combined with methods used in electronic-differential-analyzer work to provide effective means for realizing these transfer functions with a minimum of computer equipment. The basic ideas of associating high-gain amplifiers and phase-inverting amplifiers with resistor-capacitor networks are applied in order to obtain three systematic methods for synthesizing transfer functions of various degrees of complexity. The methods described are illustrated by an example.
128 Capturing the Light Fantastic: Oceanographic and Tidal Influences on Intertidal Algae

Seaweeds experience many challenges to their persistence in intertidal zone habitats. Their growth rates must exceed losses associated with a range of ecological and physiological factors including desiccation, herbivory and wave forces. Growth rates depend on an alga's ability to capture and process light to build carbon-based molecules. We examined local (tidal height) and large (oceanographic) scale influences on algal photosynthetic efficiency and light climate, respectively. At the local scale, we combined periodic measurements of physiological state using PAM fluorometry with traditional demographic monitoring of a Postelsia palmaeformis, population over a tidal height gradient. Parameter estimates derived from rapid fluorescence-irradiance curves were correlated with longer-term ecological performance measures including growth rate, morphology, survivorship and reproductive output. At larger scales, we made continuous in situ measurements of chlorophyll fluorescence and light attenuation in the intertidal zone at six sites during 2001 and 2002. Light attenuation to the benthos was sharply reduced at sites when chl-a fluorescence was high. Long-term, large-scale monitoring of intertidal zone chl-a and macroalgal abundances documents that striking differences among sites are persistent and associated with oceanographic factors. The light saturation parameter and maximum photosynthetic rate calculated for several common intertidal macrophytes, along with published values of the irradiance needed to saturate their growth rates, suggest that underwater light levels may limit intertidal algal growth where phytoplankton blooms are common and persistent. We conclude that physiological stress associated with tidal and oceanographic factors contribute to macroalgal distributions.
Hands-on practice in learning to use software: a comparison of exercise, exploration, and combined formats

This research addresses two issues in the domain of computer training (1) whether learners are able to use exploration-based practice methods effectively to learn to use software and (2) whether some minimal computing background is necessary to be successful with minimalist training and exploration practice. An empirical study was carried out to compare exploration, exercises, and a combined format consisting of an exercise followed by exploration. Subjects of both high and low computer experience were included in the study. It was thought that the combined format might lead to superior training outcomes because it would both structure learning through an exercise and allow learners to go beyond the simple procedures in the training manual through exploration. The results showed that the performance of the low-experience subjects at test did not differ based on the type of practice. However, high-experience subjects who were trained using exercises or the combined format did significantly better than those trained using exploration alone. The similarity of performance of subjects in the exercise and combined practice conditions suggests that the exercise component of the practice explains their success.
Aquatic bacterial populations and heavy metals—I. Composition of aquatic bacteria in the presence of copper and mercury salts

Abstract The effects of addition of copper (in copper sulfate) and mercury (in mercuric chloride) on the naturally occurring bacterial populations of two aquatic systems were studied. Water from each system, one brackish and one fresh water, was brought into the laboratory, and after one week stabilization period at room temperature was treated with metals. The impact of the elements was evaluated by comparing total colony forming units (TCFU), percentages of chromagenic organisms, and numbers of different colony types (diversity) in the laboratory system control with these parameters after additions of Cu and Hg. After stabilization, control (untreated) systems maintained stable TCFU counts throughout the 14-day test period. When either metal was added, an increase in TCFU occurred, a reduction in diversity was noted, and the percentage chromagens in the population varied. Similar results were observed when the elements were added simultaneously to a single system. These results indicate that heavy metal addition reduces bacterial community stability by the reduction in diversity coincident with increased TCFU of surviving organisms.
Counting Lattice Paths with an Infinite Step Set and Special Access

Abstract We count lattice paths that remain in the first quadrant. A path can come from only finitely many lattice points, and if no further restrictions apply, can go to infinitely many others. By “further restrictions” we mean a boundary line above which the paths may have to stay. Access privilege to the boundary line itself is granted from certain lattice points in the form of a special access step set, which also may be infinite. Our approach to explicit solutions of such enumeration problems is via Sheffer polynomials and functionals, using results of the Umbral Calculus.
Quantum adiabatic particle transport in optical lattices

Quantized adiabatic particle transport (QAPT) is considered and verified in a one-dimensional system using numerical simulation. More importantly, suggestions are given for ways to observe QAPT phenomena in atoms manipulated by laser beams. Although QAPT was originally considered for electrons in periodic substrate potentials, the optical systems provide a cleaner and experimentally feasible way to physically realize QAPT. The results in this paper serve as a model for the design of these experiments.
The renal cortical lymphatic system in dogs with unimpeded lymph and urine flow

The distribution and extent of the lymphatic circulation in the renal cortex was analyzed in three dogs under conditions of unimpeded lymph and urine flow. The kidneys were drip fixed with acrolein in vivo, and cortical tissue strips were prepared for light and electron microscopic examination. Analysis of 90 tissue strips revealed 38 cortical lymphatics, one third of which were intralobular in position. The intralobular lymphatic capillaries were related primarily to tubules, afferent arterioles, or renal corpuscles. The remainder of the lymphatics were located in interlobular connective tissue areas in association with the interlobular blood vessels. Interlobular lymphatics had a surface area twice that of intralobular vessels. Stereological analysis was used to estimate the volume density of the components of the renal cortex. The volume density of lymphatics was found to be 0.0014, but because of the relative infrequency of lymphatics, this value was considered to be approximate. The volume density data for non-lymphatic renal components were found to be in close agreement with published data. From these volume density values it was concluded that the volume of cortical lymph in a functioning dog kidney is equivalent to about 1% of the volume of blood in the cortical peritubular capillaries.
Structure and bonding in hexamethyldisilazane and a series of analogues, (XH3)2YH (X=C, Si, Ge and Y=N, P, As), by ab initio and density functional methods

Abstract The optimized geometries of hexamethyldisilazane (HMDZ) and a series of analogue molecules with formula (XH3)2YH (X=C, Si, Ge and Y=N, P, As) have been determined at the HF/6-31+G(d), B3LYP/6-31+G(d), MP2/6-31+G(d), and MP2/6-311+G(2d,p) levels of theory. Selected molecules also have been optimized at the QCISD/6-311+G(2d,p) level of theory. Three molecules are found to have planar or nearly planar X2YH skeletons: HMDZ, disilylamine, and digermylamine. Pyramidal inversion barriers have been calculated for all the compounds with non-planar X2YH skeletons along with vibrational frequencies for the inversion mode of molecules with planar skeletons. In addition, to investigate the relative orientation of the XH3 groups, barriers to rotation about the X–Y bonds have been determined. Where available, results for the equilibrium geometries and energy barriers are in excellent agreement with previous experimental and computational studies. Factors governing skeletal planarity were examined using natural bond orbital and natural population analyses. Negative hyperconjugation, involving transfer of electron density from the lone pair orbital on nitrogen to X–H antibonding orbitals (or Si–C antibonds in the case of HMDZ), plays a key role in stabilization of the planar or nearly planar skeletons of HMDZ, disilylamine, and digermylamine. In addition, transfer of electron density from the lone pair orbital on nitrogen to silicon or germanium d orbitals is involved to a moderate degree in the stabilization of these compounds. Finally, the significant bond polarity of Si–N and Ge–N bonds and the presence of highly charged Si(CH3)3, SiH3, or GeH3 groups are other important factors governing the skeletal planarity of HMDZ, disilylamine, and digermylamine.
Complementary Methods and Convergent Evidence in the Study of Primate Social Cognition1)

Studies of primate social cognition aim at a) documentation of social behaviors that appear to require an understanding in the animals of their own relationships and the relationships among others; an ability to anticipate behavioral effects; intentionality, and so on, and b) determination of the psychological mechanisms and mental abilities underlying this complex sociality. Thus far, the first area of investigation, which is largely descriptive, has reveived more attention than the second. The most parsimonious assumption concerning nonhuman primates is that if their behavior resembles human behavior the psychological and mental processes involved are probably similar too. This is not the same as uncritically accepting the existence of these processes; alternative hypotheses need to be formulated and tested. The present paper advocates research over a broad spectrum, with reliance on a variety of methods, and emphasis on covergent evidence. Because each method has its own strengths and weaknesses, the most convincing support for a particular explanation will involve data from a number of sources, both observational and experimental. Four research methods are discussed: Qualitative description. Sometimes referred to as "anecdotalism", this method seeks to document the animals' spontaneous solutions to unusual social problems, and exploitation of rare opportunities. This method provides a starting point for research if it suggests remarkable cognitive capacities. It is unsuitable, however, for a conclusive comparison of alternative explanations. Quantitative description. The first goal of systematic research is to delineate the range of tenable hypotheses about the phenomenon of interest, i.e. to establish the cognitively least demanding explanation that cannot be rejected as well as the most demanding explanation that seems reasonable given the species' general intelligence level. The second goal is to compare alternative explanations. The advantage of quantitative description is that it can be applied in natural or naturalistic settings; the disadvantage is that it lacks control over variables. Controlled observation. A pseudo-experimental procedure that aims at controlling certain variables. An observation following a particular event is compared with an observation unpreceded by the same event but matched to the first observation on a number of other dimensions. A disadvantage, compared to experimentation, is the dependency on spontaneous events. Experimentation. Manipulation of the animal's experience and available information is a powerful tool to select among alternative cognitive explanations. The disadvantage is that this procedure requires an unusual environment and human involvement, both of which may alter behavior. Experimental results are particularly convincing, therefore, if they agree with knowledge gained by means of observational techniques.
The Dynamics of Critical Realignments: An Analysis Across Time and Space

Much of the scholarly interest in critical realignments results from the pivotal role that ordinary citizens play during these periods. By altering their voting behavior, citizens hold political elites accountable and forge non-incremental change in policy outputs. A central question regarding realignments is thus how are citizens changing their behavior to hold elites accountable? Are citizens producing realignments by converting from one party to the opposition? Are previous non-voters becoming mobilized in response to emerging issues or crises? Or are one party’s supporters disproportionately abstaining from voting and altering the partisan balance in the process? This article makes four central contributions to our understanding of these realignment processes, or dynamics. We present a theoretical framework for the analysis of realignment dynamics, based upon the Michigan model of voting and its conception of the normal vote. Where previous dynamics studies have collectively only examined two realignments, we examine the dynamics of all presidential realignments in American electoral history. Where previous studies have often focused on national, sectional, or state levels of analysis, we focus on city- and county-level realignments, a critical advancement for an inherently local-level phenomenon such as critical realignments. Finally, unlike previous studies, we identify the factors that promote particular realignment dynamics. We find that the conversion of active partisans has produced most of the enduring change in voting behavior in the United States, with the relative contribution of different dynamics varying both across time and space. Political factors such as the strength of state and local parties and demographic factors such as changes in the size of local immigrant populations have each favored particular realignment dynamics in American electoral history.
Do the skills acquired by novice surgeons using anatomic dry models transfer effectively to the task of diagnostic knee arthroscopy performed on cadaveric specimens

Background: The use of surgical simulation in orthopaedic education is increasing; however, its ideal place within the training curriculum remains unknown. The purpose of this study was to determine the effectiveness of training novice surgeons on an anatomic dry model of the knee prior to training them to perform diagnostic arthroscopy on cadaveric specimens. Methods: Fourteen medical students were randomly assigned to two groups. The experimental group was trained to perform diagnostic arthroscopy of the knee on anatomic dry models prior to training on cadaveric specimens. The control group was trained only on cadaveric specimens. Proficiency was assessed with use of a modified version of a previously validated objective assessment of arthroscopic skill, the Basic Arthroscopic Knee Skill Scoring System (BAKSSS). The mean number of trials required to attain minimal proficiency when performing diagnostic knee arthroscopy was compared between the groups. The cumulative transfer effectiveness ratio (CTER) was calculated to measure the transfer of skills acquired by the experimental group. Results: The mean number of trials to demonstrate minimum proficiency was significantly lower in the experimental group (2.57) than in the control group (4.57) (p < 0.01). The mean time to demonstrate proficiency was also significantly less in the experimental group (37.51 minutes) than in the control group (60.48 minutes) (p < 0.01). The CTER of dry-model training for the task of performing diagnostic knee arthroscopy on cadaveric specimens was 0.2. Conclusions: Previous training utilizing an anatomic dry knee model resulted in improved proficiency for novice surgeons learning to perform diagnostic knee arthroscopy on cadaveric specimens. A CTER of 0.2 suggests that dry models can serve as a useful adjunct to cadaveric training for diagnostic knee arthroscopy but cannot entirely replace it within the orthopaedic curriculum. Further work is necessary to determine the optimal amount of training on anatomic dry models that will maximize transfer effectiveness and to determine how well skills obtained in the simulated environment transfer to the operating room.
A communicative model of violations of distancing expectations

This article presents a critique and further tests of a model proposed by Burgoon on the effects of violating conversational distance expectations. Based on the results and critique it is concluded...