cssi/SciSciGPT-SciSciNet huggingface dataset:
The standard enthalpies of ionization of sulfurous acid and the standard enthalpies of solution of sodium sulfite and sodium metabisulfite in water at 298.15 K

Abstract Standard enthalpies of ionization of sulfurous acid and the standard enthalpies of solution of Na 2 SO 3 (s) and Na 2 S 2 O 5 (s) in water at 298.15 K were measured by solution-reaction calorimetry. All operations were carried out under N 2 with particular care to exclude O 2 from the reaction system. Steps in the corrections to the standard states are outlined in detail. The results (mean ± uncertainty interval) are: Δ ion H m ∘ (H 2 SO 3 , aq) = −(17.82±0.18) kJ·mol −1 ; Δ ion H m ∘ (HSO 3 − , aq) = −(3.67±0.06) kJ·mol −1 ; Δ sol H m ∘ (Na 2 SO 3 , s) = −(13.26±0.06) kJ·mol −1 ; and Δ sol H m ∘ (Na 2 S 2 O 5 , s) = (21.34±0.07) kJ·mol −1 for the process: Na 2 S 2 O 5 (s)+∞H 2 O(l) = 2NaHSO 3 (aq). For the equilibrium: 2HSO 3 − (aq) = H 2 O(l)+S 2 O 5 2− (aq), we selected K ∘ = 0.032 and Δ r H m ∘ = −4.2 kJ·mol −1 from the litrature.
Effects of triaxial stressing on creep cavitation of grain boundaries

Abstract We investigate the influence of triaxial stressing on the growth of cavities on grain boundaries by the combined processes of plastic creep flow and grain boundary diffusion. The coupling arises from local accommodation of matter on the grain boundary near the cavity tip due to plastic creep deformability of the grains. This has the effect of shortening the diffusion path length on the grain boundary and increasing the cavity volumetric growth rate. An increase in triaxiality is found to accelerate the matter flux flowing from the cavity surfaces onto the grain boundaries and thus increase the cavity volumetric growth rate. This occurs at attainable levels of triaxiality. However, the enhancement in the triaxial stress state does not affect the effective diffusion path length very significantly. A simple formula for the volumetric growth rate of the cavity is suggested and it is found to give a good approximation to the numerically computed results.
96-GHz static frequency divider in SiGe bipolar technology

A static frequency divider designed in a 210-GHz f/sub T/, 0.13-/spl mu/m SiGe bipolar technology is reported. At a -5.5-V power supply, the circuit consumes 44 mA per latch (140 mA total for the chip, with input-output stages). With single-ended sine wave clock input, the divider is operational from 7.5 to 91.6 GHz. Differential clocking under the same conditions extends the frequency range to 96.6 GHz. At -5.0 V and 100 mA total current (28 mA per latch), the divider operates from 2 to 85.2 GHz (single-ended sine wave input).
Toolpack&#8212;An Experimental Software Development Environment Research Project

This paper discusses the goals and methods of the Toolpack project and in this context discusses the architecture and design of the software system being produced as the focus of the project. Toolpack is presented as an experimental activity in which a large software tool environment is being created for the purpose of general distribution and then careful study and analysis. The paper begins by explaining the motivation for building integrated tool sets. It then proceeds to explain the basic requirements that an integrated system of tools must satisfy in order to be successful and to remain useful both in practice and as an experimental object. The paper then summarizes the tool capabilities that will be incorporated into the environment. It then goes on to present a careful description of the actual architecture of the Toolpack integrated tool system. Finally the Toolpack project experimental plan is presented, and future plans and directions are summarized.
Development of an In-row Subsoiler Attachment to Reduce Smearing

Hardpans are prevalent throughout the southeastern United States and frequently restrict root development thus making crops susceptible to short-term droughts. In-row subsoiling has become the tillage tool of choice for alleviation of this compacted soil condition in Coastal Plain soils. However, in many soils with higher amounts of clay, smearing occurs near the bottom of the shank, thus trapping the roots in the subsoiled channel. A novel approach to disturb the bottom of the smeared zone was evaluated. Results of three experiments involving corn and cotton grown in coarse- and fine-textured soil types indicate that the use of a shank attachment designed to alleviate smearing may increase crop yields in fine-textured soils where soil smearing is common. Excessive depths of in-row subsoiling were not found to be beneficial to the crops investigated and required significantly more draft force, resulting in higher fuel requirements.
RADIATION EFFECTS ON EPOXY/CARBON-FIBER COMPOSITE

Carbon fiber-reinforced bisphenol-A epoxy matrix composite was evaluated for gamma radiation resistance. The composite was exposed to total gamma doses of 50, 100, and 200 Mrad. Irradiated and baseline samples were tested for tensile strength, hardness and evaluated using FTIR (Fourier transform infrared) spectroscopy and DSC (differential scanning calorimetry) for structural changes. Scanning electron microscopy was used to evaluate microstructural behavior. Mechanical testing of the composite bars revealed no apparent change in modulus, strain to failure, or fracture strength after exposures. However, testing of only the epoxy matrix revealed changes in hardness, thermal properties, and FTIR results with increasing gamma irradiation. The results suggest the epoxy within the composite can be affected by exposure to gamma irradiation.
First olfactory fiber as an anatomical landmark for frontal sinus surgery

Objectives/Hypothesis Access to the frontal sinuses is technically challenging owing to their anterosuperior location, diverse anatomy, close proximity to critical structures and the need to work in a relatively narrow space with angled-lens endoscopes and instruments. This study attempts to study the relationship of the first olfactory fiber with the frontal sinus posterior wall, assessing its fidelity as a surgical landmark during frontal sinus surgery. Study Design Anatomic study. Methods Fifteen cadaveric specimens were studied. Measurements were obtained bilaterally using the data from individual CT scans. Median A-P was defined as the anteroposterior (A-P) diameter measured just lateral to the intersinus septum, paramedian A-P was measured 5 mm lateral to the septum, and maximum A-P was defined as the maximum anteroposterior diameter on axial images. A surgical navigation device was used to calculate the distance between the first olfactory fiber and the posterior table of the frontal sinus. Results The mean distance between the first olfactory fiber and the posterior wall of the frontal sinus was (4.03 ± 2.7) mm on the right side and (4.2 ± 2.9) mm on the left. This distance strongly correlated with the maximum A-P diameter of the sinus. Conclusions In a cadaveric model, the first olfactory fiber was found to be an average of 4.0 mm posterior to the frontal sinus. The significant variability of this distance should be considered when using the first olfactory fiber to establish the posterior boundary of a frontal sinusotomy. Drilling no further posterior than 7 mm rostral to the first olfactory fiber would be safe in 91% of patients. Level of Evidence NA Laryngoscope, 126:1039–1045, 2016
A kinetic model of GPCRs: analysis of G protein activity, occupancy, coupling and receptor-state affinity constants.

AbstractContext: G protein-coupled receptors are vital macromolecules for a wide variety of physiological processes. Upon agonist binding, these receptors accelerate the exchange of GDP for GTP in G proteins coupled to them. The activated G protein interacts with effector proteins to implement downstream biological functions. Objective: We present a kinetic, quaternary complex model, based on a system of coupled linear first-order differential equations, which accounts for the binding attributes of the ligand, receptor, G protein and two types of guanine nucleotide (GDP and GTP) as well as for GTPase activity. Methods: We solved the model numerically to predict the extents of G protein activation, receptor occupancy by ligand and receptor coupling that result from varying the ligand concentration, presence of GDP and/or GTP, the ratio of G protein to receptor and the equilibrium constants governing receptor pre-coupling and constitutive activity. We also simulated responses downstream from G protein activ...
Arginine Enhances In Vivo Immune Responses in Young, Adult and Aged Mice

Arginine supplementation enhances in vitro lymphocyte proliferation in healthy adult humans and in rodent models. Studies examining the effect of arginine supplementation on in vivo immune responses are lacking. The purpose of this study was to determine whether arginine supplementation could enhance in vivo immune responses in adult mice and reverse known age-associated alterations in immune function of young and aged mice. Mice (1, 10 and 33 mo old) were fed a 2% arginine or an isonitrogenous diet for 2 wk. Delayed-type hypersensitivity to 2,4-dinitrofluorobenzene-challenged ears and changes in popliteal lymph node weights to injected sheep red blood cells were measured. The mean percentage of increase in ear thickness in challenged vs. unchallenged ears was 27, 35 and 24% with arginine supplementation and 7, 12 and 0% with the isonitrogenous diet in the 1-, 10- and 33-mo-old mice, respectively (P </= 0.05 for each age). Across all ages, the mean differences in popliteal lymph node weights were 1.9 +/- 0.3 vs. 1.0 +/- 0.3 mg with the arginine and isonitrogenous diets, respectively (P </= 0. 05). Only the 33-mo-old mice fed the isonitrogenous diet did not respond to this immune challenge. These findings suggest that arginine supplementation may enhance in vivo immune responses and/or reverse age-associated changes.
Learning from Prices: Public Communication and Welfare

We study the effect of releasing public information about productivity or monetary shocks using a micro-founded macroeconomic model in which agents learn from the distribution of nominal prices. While a public release has the direct beneficial effect of providing new information, it also has the indirect adverse effect of reducing the informational efficiency of the price system. We show that the negative indirect effect can dominate. Thus, the public information release may increase uncertainty about the monetary shock and reduce welfare. We find that the optimal communication policy is always to release either all or none of the information.
Economic Benefits of Management Reform in the Gulf of Mexico Grouper Fishery: A Semi-parametric Analysis

This paper uses a semi-parametric empirical model to estimate the economic benefits of adopting a property rights-based management program in the Gulf of Mexico grouper fishery. The analysis predicts that a rights-based fleet will be comprised of fewer, more cost efficient boats than under the current controlled access management program. Results indicate that in the year of our data, 1993, the smaller, more productive fleet could harvest the allowable reef fish catch at a cost saving of $2.92-$7.07 million, 12-30% less than under controlled access management. Recent tightening of controlled access regulations suggest that the benefits from management reform could be even larger in the current day fishery.
Enzymatic “Click” Ligation: Selective Cysteine Modification in Polypeptides Enabled by Promiscuous Glutathione S‐Transferase

Post-translational modifications of biomolecules represent nature's versatile chemical toolbox, allowing for precise and on-demand placement of various functional moieties in vivo.[1] Synthetic chemists have strived to develop a similar reaction toolkit with chemical orthogonality, selectivity and reactivity comparable to those of natural systems.[2] Recently, “click” chemistry has produced several powerful transformations applicable to a wide range of synthetic settings.[3] While the efficiency and chemical orthogonality of such “click” processes are remarkable, regio-control for these transformations has been limited and remains a major challenge.[4] The difficulty of selectively differentiating between two chemically identical sites within a macromolecule is routinely surmounted in natural systems by recognition elements such as binding pockets, directing groups and allosteric components. Although various enzymes have been engineered to catalyze reactions for protein modification and engineering,[5] they often require a long recognition sequence in polypeptides, and their substrate scope is relatively restricted. In certain cases enzymes are capable of recognizing and carrying out efficient transformations on more than one specific substrate, a phenomenon known as enzyme promiscuity. Promiscuous enzymes have been previously engineered to catalyze several synthetically important organic transformations.[6]
Polarization control and sensing with two-dimensional coupled photonic crystal microcavity arrays

We have experimentally studied polarization properties of the two-dimensional coupled photonic crystal microcavity arrays and observed a strong polarization dependence of the transmission and reflection of light from the structures-effects that can be employed in building miniaturized polarizing optical components. Moreover, by combining these properties with a strong sensitivity of the coupled bands on the surrounding refractive index, we have demonstrated a detection of small refractive-index changes in the environment, which is useful for construction of biochemical sensors.
Flt3L is a novel regulator of skeletal myogenesis

Various cues initiate multiple signaling pathways to regulate the highly coordinated process of skeletal myogenesis. Myoblast differentiation comprises a series of ordered events starting with cell cycle withdrawal and ending with myocyte fusion, with each step probably controlled by multiple extracellular signals and intracellular signaling pathways. Here we report the identification of Fms-like tyrokine kinase 3 ligand (Flt3L) signaling as a novel regulator of skeletal myogenesis. Flt3L is a multifunctional cytokine in immune cells, but its involvement in skeletal muscle formation has not been reported. We found that Flt3L is expressed in C2C12 myoblasts, with levels increasing throughout differentiation. Knockdown of Flt3L, or its receptor Flt3, suppresses myoblast differentiation, which is rescued by recombinant Flt3L or Flt3, respectively. Differentiation is not rescued, however, by recombinant ligand when the receptor is knocked down, or vice versa, suggesting that Flt3L and Flt3 function together. Flt3L knockdown also inhibits differentiation in mouse primary myoblasts. Both Flt3L and Flt3 are highly expressed in nascent myofibers during muscle regeneration in vivo, and Flt3L siRNA impairs muscle regeneration, validating the physiological significance of Flt3L function in myogenesis. We have identified a cellular mechanism for the myogenic function of Flt3L, as we show that Flt3L promotes cell cycle exit that is necessary for myogenic differentiation. Furthermore, we identify Erk as a relevant target of Flt3L signaling during myogenesis, and demonstrate that Flt3L suppresses Erk signaling through p120RasGAP. In summary, our work reveals an unexpected role for an immunoregulatory cytokine in skeletal myogenesis and a new myogenic pathway.
Geometry of pseudocharacters

If G is a group, a pseudocharacter f : G → R is a function which is “almost” a homomorphism. If G admits a nontrivial pseudocharacter f, we define the space of ends of G relative to f and show that if the space of ends is complicated enough, then G contains a nonabelian free group. We also construct a quasiaction by G on a tree whose space of ends contains the space of ends of G relative to f. This construction gives rise to examples of “exotic” quasi-actions on trees.
State Variation in the Determinants of Motor Vehicle Fatalities

Research on motor vehicle safety has involved virtually all modes of transportation. Most of these have been national in scope with relatively few studies focused on the determinants of motor vehicle fatalities at the state level. This paper investigates the determinants of motor vehicle fatalities across the states of California, Illinois, Louisiana, Pennsylvania, and Texas, which collectively account for 27% of U.S. motor vehicle fatalities in 2006. An important finding is that fatalities vary significantly by state even after controlling for commonly cited fatality determinants.
Virtual Crossing Number and the Arrow Polynomial

We introduce a new polynomial invariant of virtual knots and links and use this invariant to compute a lower bound on the virtual crossing number and the minimal surface genus.
Neuroeconomics: A Guide to the New Science of Making Choices

Introduction: Toward a biological science of making choices -- What are the components of choice? -- The efficacy of evaluation : what are the economic elements of the ability to evaluate risk and reward? -- The effectiveness of evaluation : what other psychological abilities affect evaluation? -- Conclusion: Future directions for the new science.
Resolution algorithms and deformations

An algorithm for resolution of singularities in characteristic zero is described. It is expressed in terms of multi-ideals, that essentially are defined as a finite sequence of pairs, each one consisting of a sheaf of ideals and a positive integer. This approach is particularly simple and seems suitable for applications to a good theory of simultaneous algorithmic resolution of singularities, specially for families parametrized by the spectrum of an artinian ring.
Computations of SAR distributions for two anatomically based models of the human head using CAD files of commercial telephones and the parallelized FDTD code

A method for importing data from computer-aided design (CAD) files for a mobile telephone into finite-difference time-domain (FDTD) simulation software is described. Although the FDTD method is well suited for the bio-electromagnetic simulations and has become the method of choice for most researchers in this area, there may be some limitations to its use. Limitations include, the description of the source (e,g., the mobile telephone) and the fact that the FDTD method requires large amounts of memory and computational power. The size of the computational space is dependent upon both the physical size of the model and its resolution. Higher frequencies of operation require higher resolutions. This could place the solution of some problems outside the capabilities of the technique. Often the telephone has to be represented by a plastic covered metal box, which approximates the shape of the actual device. The paper addresses these problems. Wires and circuit boards inside the telephone can act as resonant elements if they are not shielded. This potential problem is also considered. The large problem size associated with high-resolution FDTD simulations is accommodated by the use of a parallel implementation of the FDTD method (run on an IBM SP-2). The techniques developed are used for two anatomically based head models that have been developed from magnetic resonance imaging (MRI) of two human subjects. The usefulness of the techniques developed and comparisons of the specific absorption rates (SARs) in the two models are discussed.
On the Trail of the Higgs Boson

I review theoretical issues associated with the Higgs boson and the mystery of spontaneous breaking of the electroweak gauge symmetry. In addition, this essay is intended as an introduction to the special issue of Annalen der Physik, “Particle Physics after the Higgs”.
WEAK LENSING AS A CALIBRATOR OF THE CLUSTER MASS-TEMPERATURE RELATION

The abundance of clusters at the present epoch and weak gravitational lensing shear both constrain roughly the same combination of the power spectrum normalization and matter energy density . The cluster constraint jQ 8 M further depends on the normalization of the mass-temperature relation. Therefore, combining the weak-lensing and cluster abundance data can be used to accurately calibrate the mass-temperature relation. We discuss this approach and illustrate it using data from recent surveys. Subject headings: cosmology: theory — large-scale structure of universe
DS/SSMA communication system with trellis coding and CPM

A direct-sequence spread spectrum multiple access (DS/SSMA) communication system employing continuous phase modulation (CPM) and trellis coding is described and analyzed to obtain an estimate of the error probability. The trellis code provides significant coding gain while the CPM signal format gives desirable spectral properties. The analysis shows that significant improvement in error probability over the standard binary DS/SSMA system can be achieved with relatively simple codes. >
Aspergillomarasmine A, an inhibitor of bacterial metallo-β-lactamases conferring blaNDM and blaVIM resistance.

Silencing the deadly "bla-bla" of superbugs: The natural product aspergillomarasmine A (AMA) showed in vivo efficacy against Enterobacteriaceae, conferring broad β-lactam resistance blaNDM-1 (NDM-1: New Delhi Metallo-β-lactamase 1). In rodents, the natural product restored efficacy of the gold standard meropenem by inhibition of the Zn-containing active site in NDM-1.
Capacitor placement for conservative voltage reduction on distribution feeders

This paper proposes a strategy for placing capacitors at multiple locations on a distribution feeder to allow: 1) deeper levels of substation voltage reduction for peak load reduction; 2) power factor correction; and 3) power loss reduction. By reducing peak demand, a utility can avoid paying high prices when purchasing power or it may sell excess generation at high prices. By minimizing system losses, savings are obtained through reduced demand and energy charges. Besides a positive economic response, load reduction associated with improved power factor at the substation has a beneficial effect on voltage stability by increasing the system stability limit margin.
Inverse scattering for vowel articulation with frequency-domain data

An inverse-scattering problem is analysed for vowel articulation in the human vocal tract. When a unit-amplitude, monochromatic, sinusoidal volume velocity is sent from the glottis towards the lips, various types of scattering data acquired at the lips are examined to find whether the cross sectional area of the vocal tract can uniquely be determined by each data set. The data sets considered are the absolute value of the impedance at the lips, the pressure at the lips, the transfer function from the glottis to the lips and a Green's function at the lips. In the case of nonuniqueness, it is indicated what additional information may be used for the unique determination.
Planning and managing the physician workforce

National planning and management of the physician workforce is a multifaceted, difficult, and even controversial activity. It is an important subset of overall health workforce planning and management, which contributes to a country’s having an effective and efficient health care system. This commentary builds on a new survey of specialty considerations by Israeli medical students early in their clinical training, places it in the broader context of health workforce planning, and provides examples of some approaches and activities being taken in the United States that are applicable to other developed countries. This is a commentary on http://www.ijhpr.org/content/1/1/13. Commentary In any country the ability of persons to get the health care services they need depends upon the size, composition, and accessibility of that country’s health care workforce and health care facilities. The country’s supply of physicians is a subset of the overall health care workforce. In turn, the supplies of specific types of physician generalists and specialists are subdivisions of the total physician supply. Furthermore, within countries there tends to be large geographic variation in the distribution of the various elements of the health care workforce, which affects accessibility of services or certain types of services. It appears that each of the abovementioned issues is relevant in Israel. Recently, to address an apparent shortage of domestically trained and retained physicians, medical schools have been increasing their class sizes, and a new medical school has opened for the first time since 1974. There has also been concern that new graduates of Israeli medical schools are not choosing to train in fields such as internal medicine, general surgery, and anesthesiology, and concern about the tendency of physicians to locate centrally within the country rather than in the periphery. It is in that context that Weissman et
Prices, Markups and Trade Reform

This paper examines how prices, markups and marginal costs respond to trade liberalizaƟon. We develop a framework to esƟmate markups from producƟon data with mulƟ-product firms. This approach does not require assumpƟons on the market structure or demand curves faced by firms, nor assumpƟons on how firms allocate their inputs across products. We exploit quanƟty and price informaƟon to disentangle markups from quanƟty-based producƟvity, and then compute marginal costs by dividing observed prices by the esƟmated markups. We use India’s trade liberalizaƟon episode to examine how firms adjust these performance measures. Not surprisingly, we find that trade liberalizaƟon lowers factory-gate prices and that output tariff declines have the expected pro-compeƟƟve effects. However, the price declines are small relaƟve to the declines in marginal costs, which fall predominantly because of the input tariff liberalizaƟon. The reason is that firms offset their reducƟons in marginal costs by raising markups. Our results demonstrate substanƟal heterogeneity and variability in markups across firms and Ɵme and suggest that producers benefited relaƟve to consumers, at least immediately aŌer the reforms. Long-term gains to consumers may be higher to the extent that higher firm profits lead to new product introducƟons and growth. Indeed, firms with larger increases in markups had a higher propensity to introduce new products during this period.
Mobile jammers for secrecy rate maximization in cooperative networks

We consider a source (Alice) trying to communicate with a destination (Bob), in a way that an unauthorized node (Eve) cannot infer, based on her observations, the information that is being transmitted. The communication is assisted by multiple multi-antenna cooperating nodes (helpers) who have the ability to move. While Alice transmits, the helpers transmit noise that is designed to affect the entire space except Bob. We consider the problem of selecting the helper weights and positions that maximize the system secrecy rate. It turns out that this optimization problem can be efficiently solved, leading to a novel decentralized helper motion control scheme. Simulations indicate that introducing helper mobility leads to considerable savings in terms of helper transmit power, as well as total number of helpers required for secrecy communications.
Is It Time to Consider Global Sharing of Integral Physics Data

The innocent days of the Atoms for Peace program vanished with the suicide attack on the World Trade Center in New York City that occurred while the GLOBAL 2001 international nuclear fuel cycle conference was convened in Paris. Today's reality is that maintaining an inventory of unirradiated highly enriched uranium or plutonium for critical experiments requires a facility to accept substantial security cost and intrusion. In the context of a large collection of benchmark integral experiments collected over several decades and the ongoing rapid advances in computer modeling and simulation, there seems to be ample incentive to reduce both the number of facilities and material inventory quantities worldwide. As a result of ongoing nonproliferation initiatives, there are viable programs that will accept highly enriched uranium for down blending into commercial fuel. Nevertheless, there are formidable hurdles to overcome before national institutions will voluntarily give up existing nuclear research capabiliti...
TRANSITION METAL CHEMISTRY OF GLUCOSE OXIDASE, HORSERADISH PEROXIDASE, AND RELATED ENZYMES

Publisher Summary The purpose of this chapter is to highlight a progress in the transition metal chemistry of some enzymes that catalyze oxidative and reductive reactions. These enzymes are referred to as oxidoreductases (1,2) and transition metals are usually found in their active sites. It is essential to understand basic principles of structural organization and mechanisms of action of the key enzymes used in amperometric biosensors. These are glucose oxidase from Aspergillus niger , horseradish peroxidase (HRP), and a group of pyrroloquinoline quinine (PQQ)-dependent enzymes such as alcohol and glucose dehydrogenases. Natural substrates of HRP are aromatic amines, phenols, indoles, sulfonates, which are usually oxidized into oligomers or polymers. Mediators as electron donors act instead of H 2 A in the peroxidase catalysis. Their role is to rapidly reduce Compounds I and II into the resting state. Glucose oxidase from A. niger and horseradish peroxidase are the enzymes that catalyze absolutely different reactions.
Evolution at two levels of gene expression in yeast

Despite the greater functional importance of protein levels, our knowledge of gene expression evolution is based almost entirely on studies of mRNA levels. In contrast, our understanding of how translational regulation evolves has lagged far behind. Here we have applied ribosome profiling--which measures both global mRNA levels and their translation rates--to two species of Saccharomyces yeast and their interspecific hybrid in order to assess the relative contributions of changes in mRNA abundance and translation to regulatory evolution. We report that both cis- and trans-acting regulatory divergence in translation are abundant, affecting at least 35% of genes. The majority of translational divergence acts to buffer changes in mRNA abundance, suggesting a widespread role for stabilizing selection acting across regulatory levels. Nevertheless, we observe evidence of lineage-specific selection acting on several yeast functional modules, including instances of reinforcing selection acting at both levels of regulation. Finally, we also uncover multiple instances of stop-codon readthrough that are conserved between species. Our analysis reveals the underappreciated complexity of post-transcriptional regulatory divergence and indicates that partitioning the search for the locus of selection into the binary categories of "coding" versus "regulatory" may overlook a significant source of selection, acting at multiple regulatory levels along the path from genotype to phenotype.
Design and characterization of NULL convention arithmetic logic units

In this paper, a number of 4-bit, 8-operation arithmetic logic units (ALUs) are designed using the delay-insensitive NULL convention logic paradigm, and are characterized in terms of speed and area. Both dual-rail and quad-rail, pipelined and non-pipelined versions are developed, and the tradeoffs and design considerations for each are discussed. Comparing the various architectures shows that the fastest dual-rail and quad-rail ALUs achieve average speedups of 1.72 and 1.59, respectively, over their non-pipelined counterparts, while requiring 133% and 119% more area, respectively. Overall, the dual-rail designs are both faster and require less area than their respective quad-rail counterparts; however, the quad-rail versions are expected to consume less power.
Black Hole Mergers in the Universe.

Mergers of black hole binaries are expected to release large amounts of energy in the form of gravitational radiation. However, binary evolution models predict merger rates that are too low to be of observational interest. In this Letter, we explore the possibility that black holes become members of close binaries via dynamical interactions with other stars in dense stellar systems. In star clusters, black holes become the most massive objects within a few tens of millions of years; dynamical relaxation then causes them to sink to the cluster core, where they form binaries. These black hole binaries become more tightly bound by superelastic encounters with other cluster members and are ultimately ejected from the cluster. The majority of escaping black hole binaries have orbital periods short enough and eccentricities high enough that the emission of gravitational radiation causes them to coalesce within a few billion years. We predict a black hole merger rate of about 1.6 × 10-7 yr-1 Mpc-3, implying gravity-wave detection rates substantially greater than the corresponding rates from neutron star mergers. For the first-generation Laser Interferometer Gravitational-Wave Observatory (LIGO-I), we expect about one detection during the first 2 years of operation. For its successor LIGO-II, the rate rises to roughly one detection per day. The uncertainties in these numbers are large. Event rates may drop by about an order of magnitude if the most massive clusters eject their black hole binaries early in their evolution.
The Role of Homework in Student Learning Outcomes: Evidence from a Field Experiment

In this article, the authors describe a field experiment in the classroom where principles of micro- economics students are randomly assigned into homework-required and not-required groups. The authors find that homework plays an important role in student learning, especially so for students who initially perform poorly in the course. Students in the homework-required group have higher retention rates, higher test scores (5 to 6 percent), more good grades (Bs), and lower failure rates. The authors also study the relationship between endogenous homework submission and test performance using instrumental variable estimation and find that homework submission has a large positive effect on test performance.
Carbon-enhanced hyper-metal-poor stars and the stellar IMF at low metallicity

The two known "hyper-metal-poor" (HMP) stars, HE 0107-5240 and HE 1327-2326, have extremely high enhancements of the light elements C, N, and O relative to Fe and appear to represent a statistically significant excess population relative to the halo metallicity distribution extrapolated from [Fe/H] > -3. This study weighs the available evidence for and against three hypothetical origins for these stars: (1) that they formed from gas enriched by a primordial "faint supernova," (2) that they formed from gas enriched by core-collapse supernovae and C-rich gas ejected in rotation-driven winds from massive stars, and (3) that they formed as the low-mass secondaries in binary systems at Z ~ 10-5.5 Z☉ and acquired their light-element enhancements from an intermediate-mass companion as it passed through an asymptotic giant branch (AGB) phase. The observations interpreted here, especially the depletion of lithium seen in HE 1327-2326, favor the binary mass-transfer hypothesis. If HE 0107-5240 and HE 1327-2326 formed in binary systems, the statistically significant absence of isolated and/or C-normal stars at similar [Fe/H] implies that low-mass stars could form at this metallicity, but that masses M 1.4 M☉ were disfavored in the IMF. This result is also explained if the abundance-derived top-heavy IMF for primordial stars persists to [Fe/H] ~ -5.5. This finding indicates that low-mass star formation was possible at extremely low metallicity and that the typical stellar mass may have had a complex dependence on metallicity rather than a sharp transition driven solely by gas cooling.
Capitalization of Costs and Expected Earnings Growth

Abstract This paper offers a model that shows how the capitalization of costs affects contemporaneous earnings and the growth path of expected earnings. It makes three points. First, reported earnings under successful efforts are more price relevant than earnings under full costing or full expensing. Second, whether conditional or unconditional, conservatism always enhances the growth rate of expected earnings. Third, independent of capitalization policy, the long-run expected earnings growth rate converges either to the long-run expected free cash flow growth rate or to the depreciation rate. Therefore, while capitalization policy affects the price relevance of earnings and short-run expected earnings growth, it does not affect long-run expected earnings growth.
Supplier's involvement and success of radical new product development in new ventures

Supplier involvement is essential to a new venture seeking to develop a radical innovation. Despite this, prior literature has not adequately addressed supplier involvement in radical innovation, nor what the antecedents to increased supplier involvement are. We build and test a conceptual model of the antecedents and new product performance outcomes of supplier involvement in the development of radical innovation by new ventures. Antecedent variables (supplier's specific investments and the new venture's qualification of the supplier's abilities) are drawn from the transaction cost analysis literature. We include new venture's relative power and new venture's level of commitment to the supplier as contingency conditions. We develop a set of hypotheses relating supplier involvement to radical innovation performance, relating the antecedent variables to supplier involvement, and also testing the interaction effects of the two contingency conditions. We gather data from both new ventures and their major suppliers for 173 recent radical innovation projects, and use hierarchical regression analysis to test our hypotheses. We find that the contingency conditions moderate achieved levels of supplier involvement, and also find a direct relationship between achieved level of involvement and performance. We conclude with theoretical contributions and managerial implications.
Total Synthesis of Sanglifehrin A

The immunosuppressive agent sanglifehrin A has been prepared for the first time by total synthesis. The construction of the macrocyclic unit of the target molecule was achieved through a selective intramolecular Stille coupling, and the spirolactam unit by Paterson-aldol reactions. The final steps involve an intermolecular Stille coupling and the opening of the internal acetal unit. This convergent synthesis opens the way for the synthesis of libraries of novel sanglifehrin analogues for biological screening.
Organosoluble copper clusters as precatalysts for carbon-heteroelement bond-forming reactions: microwave and conventional heating.

The coupling of aryl iodides with alcohols under mild conditions has been explored using self-assembled octanuclear copper clusters as catalysts. Reactions involving tetrahydrofurfuryl alcohol were typically complete in 4−8 h at 110 °C using an oil bath or 1−3 h with microwave heating. High yields of alkyl aryl ethers were obtained with catalyst loadings as low as 0.4 mol % cluster.
Transvaginal Sonography as a Screening Method for the Detection of Early Ovarian Cancer

From December 1987 to December 1993, 6470 women underwent screening with transvaginal sonography (TVS) as part of the University of Kentucky Ovarian Cancer Screening Project. Two groups of women were eligible to participate in this investigation: (i) asymptomatic postmenopausal patients or patients >50 years of age, and (ii) asymptomatic women >30 years of age with a family history of ovarian cancer. Ovarian volume was calculated using the prolate ellipsoid formula (length x height x width x 0.523). An abnormal sonogram was defined by (1) an ovarian volume >10 cm3 in postmenopausal women or >20 cm3 in premenopausal women, and (2) a papillary or complex tissue projection into a cystic ovarian tumor. All women with an abnormal TVS had a repeat sonogram in 4-6 weeks. Patients with persistently abnormal scans had a serum CA-125 determination, tumor morphology indexing, and color Doppler sonography. Ninety patients (1.4%) with a persisting abnormality on TVS underwent exploratory laparotomy or laparoscopy for tumor removal. Thirty-seven patients had serous cystadenomas and six had primary ovarian cancers. Five patients had Stage IA ovarian cancer and one patient had Stage IIIB disease. Only one of the ovarian cancer patients had a palpable abnormality on pelvic examination, and none had an elevated (>35 u/ml) serum CA-125. All these patients are presently alive and well 1-5 years after conventional therapy. There was one false negative in this study, a 38-year-old white female who was noted to have a small ovarian cancer at the time of laparoscopic prophylactic oophorectomy 11 months after a normal scan. Over 17,000 screening years have been accrued and there have been no deaths from primary ovarian cancer in the screened population. A cost analysis of TVS screening is presented.
Fracture toughness computational simulation of general delaminations in fiber composites

A procedure is described to computationally simulate composite laminate fracture toughness in terms of strain energy release rate (SERR). It is also used to evaluate the degradation in laminate structural integrity in terms of displacements, loss in stiffness, loss in vibration frequencies and loss in buckling resistance. Specific laminates are selected for detail studies in order to demonstrate the generality of the procedure. These laminates had center delaminations, off-center delaminations, and pocket delaminations (center and off-center) at the free-edge and center delaminations at the interior. The lami nates had two different thicknesses and were made from three different materials. The results obtained are presented in graphical form to illustrate the effects of delamination on the laminate structural integrity and on the laminate strain energy release rate (composite fracture toughness).
Optical Spectroscopy of a Flare on Barnard’s Star

ABSTRACT We present optical spectra of a flare on Barnard’s star. Several photospheric and chromospheric species were enhanced by the flare heating. An analysis of the Balmer lines shows that their shapes are best explained by Stark broadening rather than chromospheric mass motions. We estimate the temperature of the flaring region in the lower atmosphere to be ≥8000 K and the electron density to be ∼1014 cm−3, similar to values observed in other dM flares. Because Barnard’s star is considered to be one of our oldest neighbors, a flare of this magnitude is probably quite rare.
Bilayer Phosphorene: Effect of Stacking Order on Bandgap and Its Potential Applications in Thin-Film Solar Cells

Phosphorene, a monolayer of black phosphorus, is promising for nanoelectronic applications not only because it is a natural p-type semiconductor but also because it possesses a layer-number-dependent direct bandgap (in the range of 0.3 to 1.5 eV). On basis of the density functional theory calculations, we investigate electronic properties of the bilayer phosphorene with different stacking orders. We find that the direct bandgap of the bilayers can vary from 0.78 to 1.04 eV with three different stacking orders. In addition, a vertical electric field can further reduce the bandgap to 0.56 eV (at the field strength 0.5 V/A). More importantly, we find that when a monolayer of MoS2 is superimposed with the p-type AA- or AB-stacked bilayer phosphorene, the combined trilayer can be an effective solar-cell material with type-II heterojunction alignment. The power conversion efficiency is predicted to be ∼18 or 16% with AA- or AB-stacked bilayer phosphorene, higher than reported efficiencies of the state-of-the-ar...
Simulations of the AGS MMPS storing energy in capacitor banks

The Brookhaven AGS Main Magnet Power Supply (MMPS) is a thyristor control supply rated at 5500 Amps, +/-9000 Volts. The peak magnet power is 50 MWatts. The power supply is fed from a motor/generator manufactured by Siemens. The generator is 3 phase 7500 Volts rated at 50 MVA. The peak power requirements come from the stored energy in the rotor of the motor/generator. The motor generator is about 45 years old, made by Siemens and it is not clear if companies will be manufacturing similar machines in the future. We are therefore investigating different ways of storing energy for future AGS MMPS operations. This paper will present simulations of a power supply where energy is stored in capacitor banks. Two dc to dc converters will be presented along with the control system of the power section. The switching elements will be IGCT's made by ABB. The simulation program used is called PSIM version 6.1. The average power from the local power authority into the power supply will be kept constant during the pulsing of the magnets at +/-50 MW. The reactive power will also be kept constant below 1.5 MVAR. Waveforms will be presented.
The Escape of Ionizing Photons from OB Associations in Disk Galaxies: Radiation Transfer through Superbubbles

By solving the time-dependent radiation transfer problem of stellar radiation through evolving superbubbles within a smoothly varying H I distribution, we estimate the fraction of ionizing photons emitted by OB associations that escapes the H I disk of our Galaxy into the halo and intergalactic medium (IGM). We consider both coeval star formation and a Gaussian star formation history with a time spread σt = 2 Myr. We consider both a uniform H I distribution and a two-phase (cloud/intercloud) model, with a negligible filling factor of hot gas. We find that the shells of the expanding superbubbles quickly trap or attenuate the ionizing flux, so that most of the escaping radiation escapes shortly after the formation of the superbubble. Superbubbles of large associations can blow out of the H I disk and form dynamic chimneys, which allow the ionizing radiation to escape the H I disk directly. However, blowout occurs when the ionizing photon luminosity has dropped well below the association's maximum luminosity. For the coeval star formation history, the total fraction of Lyman Continuum photons that escape both sides of the disk in the solar vicinity is fesc ≈ 0.15 ± 0.05. For the Gaussian star formation history, fesc ≈ 0.06 ± 0.03, a value roughly a factor of 2 lower than the results of Dove & Shull, where superbubbles were not considered. For a local production rate of ionizing photons ΨLyC = 4.95 × 107 cm-2 s-1, the flux escaping the disk is ΦLyC ≈ (1.5 - 3.0) × 106 cm-2 s-1 for coeval and Gaussian star formation, comparable to the flux required to sustain the Reynolds layer. Rayleigh-Taylor instabilities exist early in the OB association's evolutionary stages, possibly causing the shell to fragment and increasing fesc. However, if a significant fraction of H I is distributed in cold clouds with nH ~ 30 cm-3, fesc can be reduced by a factor of ~2-5 if the cloud properties are similar to "standard clouds" with a disk geometry.