cssi/SciSciGPT-SciSciNet huggingface dataset:
A major lineage of non-tailed dsDNA viruses as unrecognized killers of marine bacteria

The most abundant viruses on Earth are thought to be double-stranded DNA (dsDNA) viruses that infect bacteria. However, tailed bacterial dsDNA viruses (Caudovirales), which dominate sequence and culture collections, are not representative of the environmental diversity of viruses. In fact, non-tailed viruses often dominate ocean samples numerically, raising the fundamental question of the nature of these viruses. Here we characterize a group of marine dsDNA non-tailed viruses with short 10-kb genomes isolated during a study that quantified the diversity of viruses infecting Vibrionaceae bacteria. These viruses, which we propose to name the Autolykiviridae, represent a novel family within the ancient lineage of double jelly roll (DJR) capsid viruses. Ecologically, members of the Autolykiviridae have a broad host range, killing on average 34 hosts in four Vibrio species, in contrast to tailed viruses which kill on average only two hosts in one species. Biochemical and physical characterization of autolykiviruses reveals multiple virion features that cause systematic loss of DJR viruses in sequencing and culture-based studies, and we describe simple procedural adjustments to recover them. We identify DJR viruses in the genomes of diverse major bacterial and archaeal phyla, and in marine water column and sediment metagenomes, and find that their diversity greatly exceeds the diversity that is currently captured by the three recognized families of such viruses. Overall, these data suggest that viruses of the non-tailed dsDNA DJR lineage are important but often overlooked predators of bacteria and archaea that impose fundamentally different predation and gene transfer regimes on microbial systems than on tailed viruses, which form the basis of all environmental models of bacteria-virus interactions.
Supramolecular Assemblies for Transporting Proteins Across an Immiscible Solvent Interface

Polymeric supramolecular assemblies that can effectively transport proteins across an incompatible solvent interface are described. We show that electrostatics and ligand–protein interactions can be used to selectively transport proteins from an aqueous phase to organic phase. These transported proteins have been shown to maintain their tertiary structure and function. This approach opens up new possibilities for application of supramolecular assemblies in sensing, diagnostics and catalysis.
Dynamic surface water distributions influence wetland connectivity within a highly modified interior landscape

Animal movements are inherently linked to landscape structure. Understanding this relationship for highly-mobile species requires documenting their responses to spatiotemporal variability of resources. To that end, characterizing movement behaviors and resource distributions using the principles of habitat connectivity facilitates coordinated landscape planning efforts within highly modified landscapes. We tracked locations and movements for 156 dunlin (Calidris alpina) and 109 long-billed dowitchers (Limnodromus scolopaceus) overwintering in two regions with distinct water distributions in California’s Central Valley. We then compared residency rates, functional connectivity to other regions, and associations between movement distances and average habitat availability and structural connectivity of habitat at multiple temporal and spatial scales. A widespread yet highly variable regional water distribution was associated with lower residency rates and substantially higher functional connectivity to nearby regions when compared to a stable regional water distribution characterized by a large, contiguous wetland complex. Longer movements were associated with decreasing average availability and spatial aggregation of surface water. Movement models suggested shorebirds primarily responded to habitat availability at smaller scales (< 10 km) and structural connectivity at larger scales (≥ 10 km). Differences in movement behaviors suggested that wintering shorebirds will avoid long distance movements and remain resident within a wetland region when possible. Conservation and management efforts should reliably flood individual wetlands and agricultural lands from November to April and prioritize locations that maximize structural wetland connectivity and limit spatiotemporal variability of surface water throughout the Central Valley.
Discrete coulomb frictional systems subjected to periodic loading

If elastic systems with frictional interfaces are subjected to periodic loading, the system may shake down, meaning that frictional slip is restricted to the first few cycles, or it may settle into a steady periodic state involving cyclic slip. Furthermore, if the system posesses a rigid-body mode, the slip may also cause an increment of rigid-body motion to occur during each cycle — a phenomenon known as ratcheting.
What makes a good game programming assignment

Gaming in the Computer Science (CS) curriculum has received considerable attention in recent years as a way to motivate students in their coursework, as well as to encourage them to pursue CS as a college major. Although the number of approaches to using games as course assignments is vast, understanding the impact of game assignments is limited. This paper presents results of in-depth interviews with six students who participated in a study that examined the use of games as assignments. In order to obtain maximum variation in responses, a purposeful sampling method was used to select participants for the interviews. Student responses revealed that in general students like game assignments with structure and prefer games that they already know to more open ended project options.
A Review of the Morph Server and the Macromolecular Motions Database: A Standardized System for Analyzing and Visualizing Macromolecular Motions in a Database Framework

The number of solved structures of macromolecules that have the same fold and thus exhibit some degree of conformational variability is rapidly increasing. It is consequently advantageous to develop a standardized terminology for describing this variability and automated systems for processing protein structures in different conformations. We have developed such a system as a ‘front-end’ server to our database of macromolecular motions, a database that classifies proteins into a limited number of categories, first on the basis of size (distinguishing among fragment, domain, and subunit motions) and then on the basis of packing. Our system attempts to describe a protein motion as a rigid-body rotation of a small ‘core’ relative to a larger one, using a set of hinges. The motion is placed in a standardized coordinate system so that all statistics between any two motions are directly comparable. We find that while this model can accommodate most protein motions, it cannot accommodate all; the degree to which a motion can be accommodated provides an aid in classifying it. Furthermore, we perform an adiabatic mapping (a restrained interpolation) between every two conformations. This gives some indication of the extent of the energetic barriers that need to be surmounted in the motion, and, as a byproduct, results in a ‘morph movie.’ We make these movies available over the Web to aid in visualization. Many instances of conformational variability occur between proteins with somewhat different sequences. We can accommodate these differences in a rough fashion, generating an ‘evolutionary morph.’ Users have already submitted hundreds of examples of protein motions to our server, producing a comprehensive set of statistics. So far the statistics show that the median submitted motion has a rotation of 10 degrees and a maximum C-alpha displacement of 17 A. Almost all involve at least one large torsion angle charge of >140 degrees. The server is accessible at http://bioinfo.mbb.yale.edu/MolMovDB.
Spectral Clustering with a Convex Regularizer on Millions of Images

This paper focuses on efficient algorithms for single and multi-view spectral clustering with a convex regularization term for very large scale image datasets. In computer vision applications, multiple views denote distinct image-derived feature representations that inform the clustering. Separately, the regularization encodes high level advice such as tags or user interaction in identifying similar objects across examples. Depending on the specific task, schemes to exploit such information may lead to a smooth or non-smooth regularization function. We present stochastic gradient descent methods for optimizing spectral clustering objectives with such convex regularizers for datasets with up to a hundred million examples. We prove that under mild conditions the local convergence rate is \(O(1/\sqrt{T})\) where T is the number of iterations; further, our analysis shows that the convergence improves linearly by increasing the number of threads. We give extensive experimental results on a range of vision datasets demonstrating the algorithm’s empirical behavior.
Instruments and Surgical Approaches for Minimally Invasive Spinal Surgery Via Posterolateral Access

A variety of instruments have been marketed by at least five industries. All of them share the already published principles (1, 2, 3, 4): 1. Precise positioning of needle or guide pin under fluoroscopic control in the triangular working zone. 2. Use of a blunt-ended cannulated obturator or soft-tissue dilator over the previously positioned guide pin. The blunt end of the obturator will have a tendency to bypass the traversing or exiting root as it descends toward the triangular working zone. 3. Final positioning of a working cannula that is passed over the previously positioned soft-tissue dilator.
The Design of Distributed Scheduling System for Multi-Center Time-Based Metering of Air Traffic into Congested Resources

This paper describes a distributed scheduling system as created for the National Aeronautics and Space Administration’s (NASA) Multi-center Traffic Management Advisor (McTMA) prototype research system. The uses, testing, design, and operation of the proposed system are described. The system is compromised of a loosely coupled network of subschedulers that operate over short distances in order to clear conflicting merging aircraft given local points of conflict in addition to sending out constraints to other local schedulers. Delay is thereby shifted over a great deal of space and is also robust against uncertainties inherent in long-distance delay estimation for arrival times. Upon testing it was found that the proposed architecture reduced air time delays by 20-42 percent, reduced vectoring, reduced airborne holding, and gave a shorter final approach to test aircraft control centers.
Planarized Process for Single-Flux-Quantum Circuits With Self-Shunted Nb/Nb $_{x}$ Si $_{1-x}$ /Nb Josephson Junctions

We describe our process for fabricating single-flux-quantum circuits for applications in communications metrology, advanced computing, and quantum information. The process flow includes four superconducting metal layers, one junction layer, one palladium-gold bias resistor layer, and a contact pad layer. Planarization using chemical–mechanical polishing is performed on the two lower insulating layers. This process is based on Josephson junctions with niobium superconducting electrodes and self-shunted, amorphous niobium-doped silicon barriers on the insulating side near the metal-insulator transition. The barrier material is deposited by cosputtering silicon and niobium, with the junction properties controlled by the relative sputtering powers and the duration of the barrier deposition step. The profiles of the deposition rates across 3-in (76.2 mm) wafers give a corresponding radial profile of the critical current density $\boldsymbol{J_\mathrm{c}}$ that increases by $\boldsymbol{\sim }\text{46}$ % from the center to the edge of the wafer. To characterize our process, we have measured and show data for niobium metal quality and its magnetic penetration depth, as well as for wire and via inductances, and for via critical currents. The uniformity of the junction critical current $\boldsymbol{I_\mathrm{c}}$ across a wafer was measured on test chips with 2.7- ${\mu }$ m-diameter junctions. Within a 5 mm $\boldsymbol{\times }$ 5 mm area, the standard deviation of $\boldsymbol{I_\mathrm{c}}$ was $\boldsymbol{\sim }\text{2}$ % for chips near the center of the wafer and up to $\boldsymbol{\sim }\text{7}$ % for chips near the edge. We also describe process improvements and innovations under development aimed at increasing circuit density and high-speed performance.
Requirements, for Industrial Analog Faulf-Simulator

This article discusses the prerequisites that enable practical EDA solution for analog fault simulation. It shows that a strict and realistic definition set of targets, compliant with emerging IEEE standards for analog test, is crucial for the success of such a product. The Cadence® product for analog fault simulation is presented and options to mitigate the evergreen problem of analog fault simulation adoption in industrial applications is listed.
A Design Oriented Model of Plate Forming for Shipbbuilding

This paper presents a prototype of a tool, aimed at providing process information about bending and rolling of plate. The model presented is derived from first principles of mechanics and can provide a plethora of information. However, the unique aspect of this work is the development and presentation of design-oriented information, such as optimization tradeoffs of process/material selection, and process control options ranging from purely manual to mechanized to fully automatic
Bean counting ignores structural inequalities.

Deepshikha Chatterjee, an Assistant Professor in Organisational Psychology, argues that noncitizen scientists in the US are structurally disadvantaged in a system that offers them fewer opportunities in training but later measures them against their citizen peers as if both groups had started on a level playing field.
Establishing and Evaluating an ASCO Learning Cohort: a Longitudinal Project Assessing the Learning Needs and Behaviors of Oncology Professionals.

In 2013, the American Society of Clinical Oncology (ASCO)’s Continuing Education Committee recommended establishing an interprofessional, longitudinal cohort pilot project. The main goals of the cohort were to gain feedback from oncology providers on how they use resources to address their learning needs and gain insights into the utility of different ASCO educational activities. The ASCO Learning Cohort Pilot Project included 49 ASCO members that were representative of the overall Society membership demographics and ran from November 2015 through August 2016. Participants documented monthly learning needs and completed monthly feedback activities focused on specific ASCO educational resources. The Learning Cohort Pilot Project proved a viable and innovative cohort model for analyzing the learning process for oncology healthcare professionals. The development, operations, and compliance required unique infrastructure to accomplish this project. Relationships between participant demographic variables and learning preferences are reported elsewhere. The ASCO Learning Cohort Project is a unique educational project that demonstrated feasibility and has met its goals. This paper outlines the processes of establishing a learning cohort, including participant selection, project design, and participant feedback. We evaluate the project model as a means to better understand the learning needs and behaviors of oncology healthcare professionals.
Enhancing Seismic Resilience of Electric Power Distribution Systems with Mobile Power Sources

Mobile power sources (MPSs), including mobile emergency generators (MEGs), truck-mounted mobile energy storage systems (MESSs) and electric vehicles (EVs) have great potentials to be employed as grid-support resources during power grid emergency operating conditions to supply the critical loads and enhance the resilience of distribution system (DS) via a swift disaster restoration. We here investigate the MPS dispatch (i.e., routing and scheduling) in coordination with DS dynamic network reconfiguration. We propose a two-stage restoration scheme to facilitate the DS restoration following the high-impact low-probability (HILP) seismic disasters. In the first stage, a seismic hazard is simulated through a Monte-Carlo simulation (MCS) engine to estimate the unavailability of power distribution branches under a suite of seismic force scenarios. In the second stage, a mixed-integer nonlinear programming (MINLP) optimization model is formulated for DS restoration that co-optimizes the routing and scheduling of MPSs and DS dynamic network reconfiguration. The MINLP model is then linearized to a mixed-integer linear programming (MILP) model to reduce the computation complexity, where the seismic-resilience recovery strategies are generated at different timescales. The efficacy of the proposed method is evaluated on the IEEE 33-node test system and the results verify a significant reduction in the load outages and an improved power system resilience to HILP earthquakes.
THERMODYNAMICS OF ORGANIC SULFUR COMPOUNDS

Abstract Thermochemical and thermodynamic studies of organic sulfur compounds are surveyed from the classic investigations of J. Thomsen in 1886 to those in progress 73 years later. A complete listing of thermodynamic data available for ninety sulfur compounds is given in convenient tabular form with detailed literature references. The contributions of systematic investigations that began in 1948 are emphasized. These investigations provided values of thermodynamic properties that are correlated with molecular weight and structure in two ways: (a) General equations are given for computing thermodynamic properties of any linear 1-alkanethiol, alkane sulfide or symmetrical alkane disulfide, (b) Thermodynamic properties of thirty representative organic sulfur compounds are compared with those of the corresponding hydrocarbons; the comparisons yield information useful in estimating the properties of almost any sulfur compound if data are available for the hydrocarbon analog.
Increased Mortality With Paclitaxel-Eluting Stents Is Driven By Lesion Length

Abstract Background Endovascular stenting has become the first-line treatment of symptomatic peripheral artery disease of the femoropopliteal axis (FPA). Several randomized clinical trials have reported that paclitaxel-eluting stents (PESs) significantly reduce the rates of restenosis. However, a meta-analysis investigating paclitaxel-coated devices in the FPA showed a significant increase in all-cause mortality after the use of PES. The aim of this study was to compare the long-term, real-world outcomes of bare-metal stents (BMSs) and PESs for treating FPA occlusive disease. Methods A retrospective review of the medical records of 296 patients who underwent FPA stenting between January 2011 and December 2017 was performed. Patients were grouped into BMS and PES groups. The primary end point was all-cause mortality. Secondary end points included limb salvage, primary patency, primary assisted patency, and secondary patency. A comparison between the two groups within TransAtlantic Inter-Society Consensus (TASC) II subgroups was also performed. Results Of the study cohort, 101 patients (34%) received PES, whereas 195 patients (66%) underwent BMS placement. Median follow-up time was 23 months (interquartile range, 7-40 months). The 2-year all-cause mortality estimates were 12% for the PES group compared with 11.4% for the BMS group (P = .26). There were no differences in the 2-year limb salvage (90.7% vs 92%; P = .4), primary patency (78.8% vs 81.1%; P = .62), primary assisted patency (100% vs 96.5%; P = .4), and secondary patency (100% vs 98.6%; P = .26) between the PES and the BMS groups, respectively (all P > .05). These findings persisted when patients were stratified by TASC II lesions. Among patients with TASC C and D lesions, the use of PES was associated with significantly higher 2-year all-cause mortality (23.9% vs 5.1%; P = .05). After adjustment for age and other potential confounders, PES use was associated with significant increase in all-cause mortality (adjusted hazard ratio, 2.3; 95% confidence interval, 1.31-27 P = .02) in TASC C and D patients. Conclusions Consistent with the meta-analysis of several randomized clinical trials, the use of PES in a real-world setting was associated with a twofold increase in the risk of death. However, these findings were seen only among patients with TASC C and D lesions, who required multiple longer stents and potentially larger paclitaxel dose. There was no advantage in terms of patency in PES vs BMS in this population with extensive disease. Further studies of larger populations are required.
Salient or Not? The U.S. Air Travel Taxes

We exploit the abundance of tax changes in the airline industry after the DOT's full-disclosure rule. We determine the "effective" tax rate and analyze how passengers reacted to the tax changes. Hausman-type instruments are used to address the problems arising from endogenously determined prices. We show that passengers react more strongly to taxes than to price changes. In addition, this response is stronger if the airport (of origin) is close to a nearby airport with more connections available. This over-optimization parameter decreases as the passenger level increases. Significant differentials in the parameter are found for different carrier types. Hub status also appears to be a factor in shaping salience, particularly at the origin airport. Neither market structures nor competition seem to generate significant differentials. We extend the literature by examining the salience of air travel taxes and providing potential explanations for sources of over-optimization.
The Effects of P-Atoms on the Selective Dehydrogenation of C6H10 over Model Ru Surfaces

The incorporation of phosphorus into the Ru(0001) surface increases the selectivity of cyclohexene (C6H10) dehydrogenation to benzene (C6H6) by 100-fold when compared to Ru(0001) under steady-state...
How has forking changed in the last 20 years?: a study of hard forks on GitHub

The notion of forking has changed with the rise of distributed version control systems and social coding environments, like GitHub. Traditionally forking refers to splitting off an independent development branch (which we call hard forks); research on hard forks, conducted mostly in pre-GitHub days showed that hard forks were often seen critical as they may fragment a community. Today, in social coding environments, open-source developers are encouraged to fork a project in order to contribute to the community (which we call social forks), which may have also influenced perceptions and practices around hard forks. To revisit hard forks, we identify, study, and classify 15,306 hard forks on GitHub and interview 18 owners of hard forks or forked repositories. We find that, among others, hard forks often evolve out of social forks rather than being planned deliberately and that perception about hard forks have indeed changed dramatically, seeing them often as a positive non-competitive alternative to the original project.
Placing Racial Triangulation, Triangulating Place and Race: Chinese Grocery Stores in the Mississippi Delta during the Jim Crow Era

Chinese were first imported to the Mississippi Delta1 as the solution to the shortage of Black laborers and the maintenance of the plantation system after the Civil War. As foreigners and people of...
Neuropathology of murine Sanfilippo D syndrome.

Abstract Sanfilippo D syndrome (mucopolysaccharidosis type IIID) is a lysosomal storage disorder caused by the deficiency of N-acetylglucosamine-6-sulfatase (GNS). A mouse model was generated by constitutive knockout of the Gns gene. We studied affected mice and controls at 12, 24, 36, and 48 weeks of age for neuropathological markers of disease in the somatosensory cortex, primary motor cortex, ventral posterior nuclei of the thalamus, striatum, hippocampus, and lateral and medial entorhinal cortex. We found significantly increased immunostaining for glial fibrillary associated protein (GFAP), CD68 (a marker of activated microglia), and lysosomal-associated membrane protein-1 (LAMP-1) in Sanfilippo D mice compared to controls at 12 weeks of age in all brain regions. Intergroup differences were marked for GFAP and CD68 staining, with levels in Sanfilippo D mice consistently above controls at all age groups. Intergroup differences in LAMP-1 staining were more pronounced in 12- and 24-week age groups compared to 36- and 48-week groups, as control animals showed some LAMP-1 staining at later timepoints in some brain regions. We also evaluated the somatosensory cortex, medial entorhinal cortex, reticular nucleus of the thalamus, medial amygdala, and hippocampal hilus for subunit c of mitochondrial ATP synthase (SCMAS). We found a progressive accumulation of SCMAS in most brain regions of Sanfilippo D mice compared to controls by 24 weeks of age. Cataloging the regional neuropathology of Sanfilippo D mice may aid in understanding the disease pathogenesis and designing preclinical studies to test brain-directed treatments.
On the design of criminal trials: The benefits of a three-verdict system

We propose adding a third, intermediate, verdict to the two-verdict system used in criminal trials. We show that the additional verdict can be used to distinguish between convicted defendants, based on the residual doubt regarding their guilt at the end of the trial, in a way that improves welfare and does not increase the set of innocent defendants who are wrongly convicted. It can also be guaranteed that wrongfully convicted defendants do not serve longer sentences, provided that the sentence in the two-verdict system was not too inefficiently low. Since even acquitted defendants may face a social stigma, we also consider using the additional verdict to distinguish between acquitted defendants, and provide conditions under which this improves welfare. Generalizations to multi-verdict systems with a larger number of verdicts are also explored. We also consider plea bargains, and show that a properly chosen plea in a two-verdict system leads to higher welfare than any multi-verdict system, and is in fact the optimal mechanism. Finally, we consider the impact of multiple verdicts on the incentives to gather evidence, and show that the effect is generally positive. ∗We thank Robert Burns, Eddie Dekel, Fuhito Kojima, Adi Leibovitz, Paul Milgrom, and Jean Tirole and seminar participants at UC Berkeley, Seoul National University, and the NBER Summer Institute Law and Economics Workshop for helpful comments. David Rodina provided outstanding research assistance. Strulovici gratefully acknowledges financial support from an NSF CAREER Award (Grant No. 1151410) and a fellowship form the Alfred P. Sloan Foundation. Siegel: Department of Economics, The Pennsylvania State University, University Park, PA 16802, rus41@psu.edu. Strulovici: Department of Economics, Northwestern University, Evanston, IL 60208, b-strulovici@northwestern.edu.
Are men at greater risk of lean mass deficits in rheumatoid arthritis

Objective We aimed to determine if there were sex differences in lean body mass (LBM) in patients with rheumatoid arthritis (RA) when compared with sex- and race-specific National Health and Nutrition Examination Survey (NHANES) reference data, and to investigate the impact of sex differences in risk factors for LBM deficits. Methods Dual x-ray absorptiometry measures of whole body LBM and appendicular LBM (arms and legs, appendicular lean mass [ALM]) were obtained on a total of 190 subjects from 2 independent cohorts (141 from San Francisco [SF], 49 from Philadelphia [PA]), expressed as indices adjusted for height (LBM index and ALM index, kg/m2), and converted to sex- and race-specific Z scores relative to age and based on NHANES data. Sarcopenia was defined using 4 different sex-specific definitions. Multivariable linear and logistic regression analyses adjusted for disease activity, disease duration, physical activity, anti–cyclic citrullinated peptide seropositivity, fat mass index, and glucocorticoid use. Results While there were significant differences between the 2 cohorts, ALM index Z scores were significantly lower in men compared to women in both (SF: −1.43 versus −0.43, P < 0.0001; PA: −0.83 versus −0.06, P = 0.03). Observed sex differences were significant after adjustment in multivariable analyses within both cohorts. Odds of sarcopenia were 3 to 8 times greater in men in the SF cohort. Men in the PA cohort also had a higher, but nonsignificant, risk of sarcopenia. Conclusion RA is associated with significant LBM deficits, with greater deficits observed in men. Future study may help elucidate the mechanisms driving greater deficits among men.
Constrained Locally Corrected Nyström Method

A generalization of the locally corrected Nystrom (LCN) discretization method is outlined wherein sparse transformations of the LCN system matrix are obtained via singular- value decompositions of local constraint matrices. The local constraint matrices are used to impose normal continuity of the currents across boundaries shared by mesh elements. Due to the method’s simplicity and flexibility, it is straightforward to develop high-order constrained LCN (CLCN) systems for different formulations and mesh element types. Numerical examples demonstrate the memory savings provided by the CLCN method and its improved accuracy when applied to geometries with sharp edges. It is also shown that the CLCN method maintains the high-order convergence of the LCN method, and it eliminates the need to include line charges in Nystrom-based discretizations of formulations that involve the continuity equation.
Spectroscopic Properties of C-Phycocyanin and of Its α and β Subunits

Abstract Synechococcus sp. (Anacystis nidulans) C-phycocyanin and its α and β subunits have been examined with respect to spectroscopic properties and aggregation behavior. In 0.05 m phosphate buffer at pH 7.0, and a protein concentration of 2.1 x 10-5 m, the α subunit exhibited a λmax of 620 nm (em = 0.98 x 105 m-1 cm-1), and a maximum molecular ellipticity, [θ]620, of 30.2 x 104 deg cm2 per dmole, while the β subunit exhibited a λmax of 608 nm (em = 1.43 x 105 m-1 cm-1), and a maximum [θ]600 of 56.1 x 104 deg cm2 per dmole. Fluorescence polarization spectra of native phycocyanin indicate the presence of two different chromophore types in this protein, those that absorb at shorter wave length (s type) sensitizing those that absorb and emit at longer wave length (f type) (see Teale, F. W. J., and Dale, R. E. (1970) Biochem. J. 116, 161–169). The absorption characteristics of the β subunit indicate that it contains the s type of chromophore, whereas those of the α subunit are consistent with the presence of the f type of chromophore. As reported earlier by others, aggregation of phycocyanin results in a red shift of the absorption maximum, and a large increase in the extinction coefficient. Phycocyanin, under conditions where it is essentially monomeric, i.e. 7.2 x 10 -7 m protein in 0.05 m phosphate buffer at pH 7.0, is characterized by a λmax of ∼615 nm (em ∼ 2.3 x 105 m-1 cm-1), while hexameric phycocyanin, in 0.2 m acetate buffer at pH 5.5, exhibits a λmax of 621 nm (em = 3.33 x 105 m-1 cm-1). Changes in the circular dichroism spectrum observed upon phycocyanin aggregation suggest strong intermolecular interaction between the chromophores. Phycocyanin, formed by recombination of α and β subunits, was found to be indistinguishable from native phycocyanin with respect to circular dichroism and absorption spectra.
Levels of 42Sc from 40Ca(3He, p)42Sc and 40Ca(3He, pγ)42Sc

Abstract Levels of 42Sc at 0.62, 1.51, 1.59, 1.88, 2.22, 2.28, 2.40, 2.50, 2.64, 2.82, 3.09, 3.25, 3.33, 3.39 and 3.47 MeV have been studied by means of the 40Ca(3He, p)42Sc reaction at 10, 12 and 15 MeV incident energies. Angular distributions have been measured which are consistent with spin assignments of J = 0, 1, 3 and 0 for the ground state, 0.62, 1.51 and 1.88 MeV excited states of 42Sc, respectively. Spin assignments have been made on the basis of a DWBA analysis of the 12 MeV angular distributions. The assignments are supported by observations of the gamma decays of the 0.62, 1.51 and 2.82 MeV states in coincidence with protons from the 40Ca(3He, pγ)42Sc reaction at 10 MeV incident energy.
Approximation Algorithms for Domatic Partitions of Unit Disk Graphs

We prove a new structural property regarding the "skyline" of uniform radius disks and use this to derive a number of new sequential and distributed approximation algorithms for well-known optimization problems on unit disk graphs (UDGs). Specifically, the paper presents new approximation algorithms for two problems: domatic partition and weighted minimum dominating set (WMDS) on UDGs, both of which are of significant interest to the distributed computing community because of applications to energy conservation in wireless networks. Using the aforementioned skyline property, we derive the first constant-factor approximation algorithm for the domatic partition problem on UDGs. Prior to our work, the best approximation factor for this problem was O (logn ), obtained by simply using the approximation algorithm for general graphs. From the domatic partition algorithm, we derive a new and simpler constant-factor approximation for WMDS on UDGs. Because of "locality" properties that our algorithms possess, both algorithms have relatively simple constant-round distributed implementations in the $\mathcal{LOCAL}$ model, where there is no bound on the message size. In addition, we obtain O (log2 n )-round distributed implementations of these algorithms in the $\mathcal{CONGEST}$ model, where message sizes are bounded above by O (logn ) bits per message.
Proving properties of typed lambda terms: Realizability, covers, and sheaves

We present a general method for proving properties of typed lambda terms. This method is obtained by introducing a semantic notion of realizability which uses the notion of a cover algebra (as in abstract sheaf theory). For this, we introduce a new class of semantic structures equipped with preorders, called preapplicative structures. In this framework, a general realizability theorem can be shown. Applying this theorem to the special case of the term model, yields a general theorem for proving properties of typed lambda terms, in particular, strong normalization and confluence. This approach clarifies the reducibility method by showing that the closure conditions on candidates of reducibility can be viewed as sheaf conditions.
Send Message into a Definite Future

Rivest et al proposed a time-lock puzzle scheme for encrypting messages which can only be decrypted in the future. Such a puzzle specifies an algorithm for decrypting the message locked in and the specified algorithm has a well understood time complexity. However, that time-lock puzzle scheme does not provide a means for one to examine whether a puzzle has been formed in good order. Consequently, one may foolishly waste a lengthy time on trying to solve an intractable problem. This weakness prohibits that scheme from applications that involve mutually untrusted parties. We propose a new time-lock puzzle scheme which includes an efficient protocol that allows examination of the time needed for decrypting the message locked in.
Wear at high sliding speeds and high contact pressures

Abstract Metal on metal wear at high sliding speeds and high contact pressures results in the melting of one or both of the sliding solid bodies due to heat generated at the contact interface. Understanding the influence of sliding speeds and contact pressures on normalized wear rates is important in developing predictive models for designing more efficient and effective engineering system components. Typical engineering applications subjected to extreme sliding conditions include ultrahigh speed machining, rocket sleds, large caliber cannon, and electromagnetic launchers. Sliding speeds on the order of 1000 m/s and contact pressures in excess of 100 MPa are common in these applications and difficult to replicate in a laboratory environment. A unique electromagnetic tribometer based on a minor caliber electromagnetic launcher has been designed and implemented to characterize wear deposition of a 6061-T6 aluminum pin (slider) on a UNS C11000-H2 copper flat (guider) at sliding speeds from 0 to 1200 m/s and contact pressures from 100 to 225 MPa. Optical microscopy and 3D profilometry were used to investigate and quantify slider wear. Three distinct wear regions were observed. Test results provided evidence that the aluminum slider contact interface was molten and experimental wear data showed a dependence on both pressure and velocity. Comparisons between melt lubrication theory and experimental data provide insight into the nature of the contact interface under the sliding conditions tested.
On approximating four covering and packing problems

In this paper, we consider approximability issues of the following four problems: triangle packing, full sibling reconstruction, maximum profit coverage and 2-coverage. All of them are generalized or specialized versions of set-cover and have applications in biology ranging from full-sibling reconstructions in wild populations to biomolecular clusterings; however, as this paper shows, their approximability properties differ considerably. Our inapproximability constant for the triangle packing problem improves upon the previous results in [A. Caprara, R. Rizzi, Packing triangles in bounded degree graphs, Inform. Process. Lett. 84 (4) (2002) 175-180; J. Chlebikova, M. Chlebik, Complexity of approximating bounded variants of optimization problems, Theoret. Comput. Sci. 354 (3) (2006) 320-338]; this is done by directly transforming the inapproximability gap of Hastad for the problem of maximizing the number of satisfied equations for a set of equations over GF(2) [J. Hastad, Some optimal inapproximability results, in: Proc. of the 29th Annual ACM Symp. on Theory of Computing, 1997, pp. 1-10] and is interesting in its own right. Our approximability results on the full siblings reconstruction problems answers questions originally posed by Berger-Wolf et al. [T.Y. Berger-Wolf, B. DasGupta, W. Chaovalitwongse, M.V. Ashley, Combinatorial reconstruction of sibling relationships, in: Proc. of the 6th International Symposium on Computational Biology and Genome Informatics, 2005, pp. 1252-1255; T.Y. Berger-Wolf, S. Sheikh, B. DasGupta, M.V. Ashley, I. Caballero, W. Chaovalitwongse, S.L. Putrevu, Reconstructing sibling relationships in wild populations, Bioinformatics 23 (13) (2007) i49-i56] and our results on the maximum profit coverage problem provides almost matching upper and lower bounds on the approximation ratio, answering a question posed by Hassin and Or [R. Hassin, E. Or, A maximum profit coverage algorithm with application to small molecules cluster identification, in: 5th International Workshop Experimental Algorithms, in: Lecture Notes in Comput. Sci., vol. 4007, Springer-Verlag, 2006, pp. 265-276].
Prey-associated head-size variation in an invasive lizard in the Hawaiian Islands

Biological invasions are recognized as a primary driver of large-scale changes in global ecosystems. This study addresses ecomorphological variation in head size within and among populations of an ecologically destructive invasive predator, and evaluates the potential roles of environmental components in phenotypic differentiation. We used four size-corrected measurements of head morphology in Jackson's chameleons, Trioceros jacksonii xantholophus (N = 319), collected from multiple Hawaiian Islands to assess phenotypic variation among and within islands. Results of analysis of variance (ANOVA) comparing chameleon head size (PC1) among islands revealed significant differences (mean difference > 5%) associated with variation in both rainfall and diet composition using Mann–Whitney U-tests and chi-squared analyses. These results suggest that morphological differentiation among populations from different islands has occurred over a relatively short ecological timescale, and is likely the result of ecomorphological adaptation to differences in exploited prey hardness. Intra-island allopatric population variation, however, was also detected in this study. Although we might expect that genetic change is the more likely explanation for differences between islands than within, and that plasticity may be more likely an explanation for the within- than the between-island differences, it is also possible that both within- and between-island patterns are the results of genetic change, or of plasticity.
Implementation and adherence issues in a workplace treadmill desk intervention.

We report experiences, observations, and general lessons learned, specifically with regards to participant recruitment and adherence, while implementing a 6-month randomized controlled treadmill de...
Choosing Sport Management as a College Major

The purpose of this study was to better understand sport management students within departments of parks, recreation, and tourism, and to address the often uneasy fit faculty experience when trying...
Colonoscopy screening in the elderly: When to stop?

Abstract Objectives The age to begin colorectal cancer (CRC) screening is based on the risk of neoplasia and is published in screening guidelines. The age to stop screening is unknown but should be based, in part, on the same principle. The purpose of this study was to establish whether the prevalence of neoplasia detected by colonoscopy diminished with advancing age, to warrant ceasing colonoscopic screening. Methods The endoscopic and pathology reports of all asymptomatic subjects undergoing colonoscopy for the purpose of CRC screening or an evaluation of abdominal pain or change in bowel habits between 1997 and 2000 were reviewed. A multivariate logistic regression analysis was used to assess the effect of age, gender, and indication for examination on the prevalence of neoplasia, as well as on having more than two adenomas, advanced adenomas (tubulovillous, villous, severe dysplasia, or size ≥ 1 cm), and invasive cancers. Results A total of 915 patients were included. Of these, 50% were male, with a mean age of 65 yr (range 50–100). Neoplasia peaked in the seventh decade, with a fall thereafter (p = 0.009). Numerous adenomas, advanced adenomas, and invasive cancers increased with age. The yield for overall neoplasia, advanced adenomas, and more than two adenomas was higher in the screening group than in the symptomatic group. More invasive cancers were found in the symptomatic group compared with the asymptomatic group, but this did not achieve statistical significance (4 vs 1, p = 0.44). Conclusions The prevalence of advanced neoplasia continues to increase with age. Subjects undergoing colonoscopy for screening had a greater risk for neoplasia than did subjects with symptoms. There is no decline in yield of advanced neoplasia to justify stopping screening colonoscopy in the elderly.
Investigation of the Flopping Regime of Two-, Three-, and Four-Plate Arrays

The variation of the base pressure coefficient (Cp) and the characteristics of the power spectra of the velocity for arrays of two-, three- and four-plates aligned normal to the flow are presented. The wakes downstream of the plates in the array are shown to exhibit behavior that varies between stable modes, flopping and quasi-stable behavior depending on the s/t distance (where s is the spacing between the top and bottom surfaces of adjacent plates and t is the thickness of the plate). For the two and three-plate arrays with s/t =0.25, peaks in the power spectra of about 48.2 and 98.1 Hz which correspond to Strouhal numbers of 0.06 and 0.11 are observed. For the four-plate array with s/t =0.192, no clear peaks are visible. Probability density functions of uncalibrated hot-wire signals show that the peaks in the power do not correspond to continuously periodic fluctuations
Mechanisms of reduced solute diffusivity at nanoconfined solid-liquid interface

Abstract We report results from molecular simulations that reveal the causes of reduced diffusivity at solid–liquid interfaces in the presence of nanoscale confinement. The diffusion of a 2 M glucose solution was simulated inside a 10 nm silica channel together with the calculated thermodynamic properties of diffusion. A strong energy–entropy compensation mechanism was found at the interface with a free energy minimum of −0.6 kcal/mol. Using the Eyring equation the average jump length was reduced by 15% at interface. The complete loss of solute diffusivity at silica surface was explained by the substantial loss of the probability of productive displacements. The results suggested that glucose molecule diffusivity close to the surface might be related to a stiffer cage of the hydration shell, which affects the probability of cage breaking. These results help in understanding of diffusion mechanisms at interface and predicting mass transport in nanoconfinement for engineering and biomedical applications.
Social structure of feral house mouse (Mus musculus L.) populations: Effects of resource partitioning

1. Social structure of hourse mouse (Mus musculus L.) populations in quarter-acre (0.1-ha) enclosures was organized differently with respect to centralized and decentralized food (corn) sites. Analysis of social structure indicated a well defined demic organization in populations containing a single, centralized food depot, whereas social structure in decentralized grids was more flexible. 2. A newley-derived dominance index, based on urinary marking patterns, indicated that social dominants were associated with food site location. Subordinate males were less likely to be trapped at food sites in centralized grids than were dominants; subordinate males were excluded to a lesser extent from food sites in decentralized grids. 3. Standard pairing experiments upon termination of the study substantiated that dominant males had significantly higher urinary marking patterns than subordinate males.
Particle nonuniformity effects on particle cloud flames in low gravity

Experimental and analytical studies of particle cloud combustion at reduced gravity reveal the substantial roles that particle cloud nonuniformities may play in particle cloud combustion. Macroscopically uniform, quiescent particle cloud systems (at very low gravitational levels and above) sustain processes which can render them nonuniform on both macroscopic and microscopic scales. It is found that a given macroscopically uniform, quiescent particle cloud flame system can display a range of microscopically nonuniform features which lead to a range of combustion features. Microscopically nonuniform particle cloud distributions are difficult experimentally to detect and characterize. A uniformly distributed lycopodium cloud of particle-enriched microscopic nonuniformities in reduced gravity displays a range of burning velocities for any given overall stoichiometry. The range of observed and calculated burning velocities corresponds to the range of particle enriched concentrations within a characteristic microscopic nonuniformity. Sedimentation effects (even in reduced gravity) are also examined.
Ensuring a knowledgeable and committed gerontological nursing workforce

There is a growing societal need for professional nurses who are knowledgeable and committed to working with older adults. In order to address this need, a small study that included self-evaluation and curriculum review was conducted by faculty at one Midwestern nursing program in the United States. A moderately positive attitude, moderately high knowledge, and moderate pursuit of knowledge of older adults were identified with the faculty in the presence of limited curricular content of gerontology. Implications for nursing education included continuing education for nursing faculty and program support in nursing curricula.