cssi/SciSciGPT-SciSciNet huggingface dataset:
Adsorbed xenon propellant storage: are nanoporous materials worth the weight?

Xenon is used as a propellant for spacecraft. Conventionally, xenon is compressed to high pressures (75–300 bar) for bulk storage onboard the spacecraft. An adsorbed xenon storage system based on nanoporous materials (NPMs) could, potentially, (i) reduce the storage pressures, (ii) allow for thinner-walled and lighter pressure vessels, and (iii) if the NPM itself is sufficiently light, reduce the overall mass of the storage system and, thus, of the payload of the rocket launch. To investigate, we develop a simple mathematical model of an adsorbed xenon storage system by coupling a mechanical model for the pressure vessel and a thermodynamic model for the density of xenon adsorbed in the NPM. From the model, we derive the optimal storage pressure, tailored to each NPM, with the objective of minimizing the mass of the materials (walls of the pressure vessel + NPM) required to store the xenon. The model enables us to: (i) rank NPMs for adsorbed xenon propellant storage, (ii) compare adsorbed storage to the baseline of bulk storage, and (iii) understand what properties of NPMs are desirable for adsorbed xenon propellant storage. We use the model to evaluate several NPMs, mostly metal–organic frameworks (MOFs), for adsorbed xenon propellant storage at room temperature, using experimental xenon adsorption data as input. We find Ni-MOF-74 and MOF-505 outperform activated carbon, a traditional adsorbent. However, each optimized adsorbed xenon storage system is heavier than the optimized bulk storage system, owing dominantly to the large mass of the NPM itself. To provide a lighter adsorbed xenon storage system than a bulk storage system, our model suggests to pursue light adsorbents with a high gravimetric saturation loading of xenon.
Efficient representation and validation of proofs

This paper presents a logical framework derived from the Edinburgh Logical Framework (LF) that can be used to obtain compact representations of proofs and efficient proof checkers. These are essential ingredients of any application that manipulates proofs as first-class objects, such as a Proof-Carrying Code system, in which proofs are used to support easy validation of properties of safety-critical or untrusted code. Our framework, which we call LF/sub i/, inherits from LF the capability to encode various logics in a natural way. In addition, the LF/sub i/ framework allows proof representations without the high degree of redundancy that is characteristic of LF representations. The missing parts of LF/sub i/ proof representations can be reconstructed during proof checking by an efficient reconstruction algorithm. We also describe an algorithm that can be used to strip the unnecessary parts of an LF representation of a proof. The experimental data that we gathered in the context of a Proof-Carrying Code system shows that the savings obtained from using LF/sub i/ instead of LF can make the difference between practically useless proofs of several megabytes and manageable proofs of tens of kilobytes.
Southern Hemisphere jet latitude biases in CMIP5 models linked to shortwave cloud forcing

[1] Substantial biases in shortwave cloud forcing (SWCF) of up to ±30 W m−2are found in the midlatitudes of the Southern Hemisphere in the historical simulations of 34 CMIP5 coupled general circulation models. The SWCF biases are shown to induce surface temperature anomalies localized in the midlatitudes, and are significantly correlated with the mean latitude of the eddy-driven jet, with a negative SWCF bias corresponding to an equatorward jet latitude bias. Aquaplanet model experiments are performed to demonstrate that the jet latitude biases are primarily induced by the midlatitude SWCF anomalies, such that the jet moves toward (away from) regions of enhanced (reduced) temperature gradients. The results underline the necessity of accurately representing cloud radiative forcings in state-of-the-art coupled models.
Pension reform in Hungary : a preliminary assessment

Hungary is entering the fourth year of a multi-pillar pension reform that has proved popular among workers despite initially lukewarm support from the government that succeeded the reforming government, and despite the poor initial performance of capital markets because of Russia's crisis in 1998. Roughly half the labor force joined the new system voluntarily. Most who switched were younger than 40. Many people switched to the system because it offered more risk diversification. The pay-as-you-go (PAYG) system, which had been severely damaged by repeated manipulation of its parameters, clearly offered a low return on contributions. The new system is still predominantly PAYG. The first pillar accounts for more than two-thirds of the total contribution, but the new second pillar offers the chance of higher average returns on contributions. Most workers probably intuited the risk and returns inherent in a pure PAYG system and mixed system, including the capital market risk in the second pillar and the political risk in the PAYG pillar. The new system offers better prospects of long-run risk-adjustment returns for young workers, and most young workers effectively opted for the new system. But the new system was probably oversold as well, making older workers - who would be better off staying in the reformed PAYG system - switch too. The government has so far decided not to increase the contribution to the second pillar from 6 to 8 percent, as originally planned, so efficiency gains in labor and capital markets may also be smaller than expected. Addressing projected deficits in the PAYG system may require further adjustments, such as delaying the retirement age and shifting to indexed prices, reducing net benefits to future generations. Reform has sharply reduced the severe initial bias against future generation but hasn't eliminated it altogether. The voluntary switching strategy achieves the same outcome as a forced switch based on an arbitrarily cutoff age, while preventing legal problems and contributing to the reduction of the implicit pension debt. But it leaves a few individuals worse of the if they'd chosen their best option - a problem a well-designed public information campaign can reduce.
Scaling the dynamical systems approach to path planning

As robotic agents are called upon to perform in increasingly complex and naturalistic physical environments, it will be necessary to develop design strategies that enable the specification of complex tasks that can be carried out in flexible ways. This requires the ability to react flexibly to dynamically changing environments as well as the ability to perform decision-making and sequencing of behavior. We describe an approach to decision-making and sequencing that utilizes the qualitative theory of dynamical systems to model stable decision-making in changing environments. The task dynamics methodology is considered as an approach to scaling the 'dynamical systems' approach to autonomous path planning.
MAP decoding for satellite channels

Error correction coding can be used to mitigate fading and interference in wireless communication systems. Decoding is most effective when soft information is fed to the decoder. Practical receivers often have a concatenation of decoders, such as an equalizer followed by an error correction decoder. Hence, the first decoder must generate soft information for the second decoder. This paper considers generation of maximum a posteriori (MAP) soft information at a bit level and presents an algorithm to generate this soft information. The algorithm is applied to a turbo decoder and an equalizer-Viterbi decoder operating on satellite channels with Ricean fading.
Simulating humans and lower animals

This paper summarizes material on the simulation of humans and lower animals presented by the author in an invited talk delivered at the Third International Conference on Motion in Games.
Future Directions in Food Safety

The recent success that the USDA Food Safety Inspection Service has had in 2003 and 2004 of reversing the steadily increasing trend in Class 1 recalls is welcomed. In agreement with those statistics are the FSIS microbiological results for Escherichia coli O157:H7 in raw ground beef, which also showed a decrease in 2003. But there is much work to be done in food safety and much more to achieve. It is imperative that while addressing food-safety issues, we should understand the role that the environmental microbiology, public health epidemiology, aerobiology, molecular microbial ecology, occupational health, industrial processes, municipal water quality, and animal health have on food safety. Although it is a difficult task, a concerted effort by industry, academic, and governmental researchers can accomplish the goal. Here we discuss the future directions and applications in the distribution and spread of foodborne hazards, methods for microbial detection and differentiation, intervention strategies for farm pathogen reduction, targeting waste at animal production sites, considerations on antimicrobial resistance, food-safety storage and preparation strategies, food irradiation, new and emerging food-safety hazards, and quantitative microbial food-safety risk assessment. Although this does not comprise an exhaustive list of food-safety issues, these are the areas that, we think, require considerable attention by researchers. Not only we need to strive to improve food safety through new strategies, processes, and applications, but we also need to be flexible and observant to readily handle the new and emerging food-safety problems, whether they are within our borders or global. At present, the United States has one of the safest food-safety systems in place. However, although this is not a time for complacency, our research endeavors should be designed to keep pace with the food-safety needs of the future.
Revisited: aerosol corticosteroids in the treatment of childhood asthma.

Systemic corticosteroids were introduced in the 1950s for the treatment of asthma. Usually, excellent results were obtained although a number of side effects became apparent. Prolonged use of corticosteroid therapy for asthma remains quite controversial, and it is often regarded as an inappropriate treatment modality. Inasmuch as complications from corticosteroids are largely dependent on dose and duration of therapy, it was reasoned that by topically administering the corticosteroids, the amount of drug necessary to control symptoms would be reduced and, in turn, lessen the number of adverse effects. Initially developed corticosteroid aerosols produced variable effectiveness with associated systemic side effects.1
The cooling history and the depth of detachment faulting at the Atlantis Massif oceanic core complex

[1] Oceanic core complexes (OCCs) are domal exposures of oceanic crust and mantle interpreted to be denuded to the seafloor by large slip oceanic detachment faults. We combine previously reported U-Pb zircon crystallization ages with (U-Th)/He zircon thermochronometry and multicomponent magnetic remanence data to determine the cooling history of the footwall to the Atlantis Massif OCC (30°N, MAR) and help establish cooling rates, as well as depths of detachment faulting and gabbro emplacement. We present nine new (U-Th)/He zircon ages for samples from IODP Hole U1309D ranging from 40 to 1415 m below seafloor. These data paired with U-Pb zircon ages and magnetic remanence data constrain cooling rates of gabbroic rocks from the upper 800 m of the central dome at Atlantis Massif as 2895 (+1276/−1162) °C Myr−1 (from ∼780°C to ∼250°C); the lower 600 m of the borehole cooled more slowly at mean rates of ∼500 (+125/−102) °C Myr−1(from ∼780°C to present-day temperatures). Rocks from the uppermost part of the hole also reveal a brief period of slow cooling at rates of ∼300°C Myr−1, possibly due to hydrothermal circulation to ∼4 km depth through the detachment fault zone. Assuming a fault slip rate of 20 mm/yr (from U-Pb zircon ages of surface samples) and a rolling hinge model for the sub-surface fault geometry, we predict that the 780°C isotherm lies at ∼7 km below the axial valley floor, likely corresponding both to the depth at which the semi-brittle detachment fault roots and the probable upper limit of significant gabbro emplacement.
Novel antennas for personal communications including biological effects

The electromagnetic interaction between handset-mounted antennas and the nearby biological tissue is a key consideration in modern personal communications. A thorough investigation of this antenna-tissue interaction using the finite-difference time-domain (FDTD) electromagnetic simulation approach is presented using detailed models of real-life antennas on a transceiver handset. Representative examples of external and internal antenna configurations are considered. Detailed models of the human head and hand are implemented to investigate the effects of the tissue location and physical model on the antenna performance. The specific absorption rate (SAR) in the tissue is examined for several different antenna/handset configurations. It is found that for a head and handset antenna separation of 2 cm, the SAR in the head has a peak value between 0.9 and 3.8 mW/g and an average value between 0.06 and 0.10 mW/g for 1 W of power delivered to the antenna. Additionally, the head and hand could absorb between 48 and 68% of the power delivered to the antenna.
High action thyristors for pulsed applications

High energy pulsers for various applications have been constructed by utilizing several different classes of high action switches. Most commonly used switches are high-pressure spark gaps, vacuum switches of varying architectures and solid state thyristors with different gate structures. All these categories of switches are capable of switching large number of coulombs. Spark gaps and vacuum switches have life time dependent on accumulated total coulomb transfer as a dominant rating factor. For the solid state thyristors, the action (current squared times pulse width) is the most significant parameter. Thyristors hold potential for applications in rugged duty, long life high-energy pulsers. Thyristors with different gate structures have been investigated. These thyristors have been designed for commercial low frequency applications. To use them for intended pulsed applications, the gate structure must be optimized, so that the rate of plasma spreading across the wafer is increased to switch maximum peak current at desired di/dt. 125 mm thyristors with different gate structures were tested on a 3.7 mF capacitor bank that had a resistance of 9 m/spl Omega/ and an inductance of 800 nH. Measurements of the current through the thyristor and the voltage drop across it show that power dissipated by the device could be reduced if the plasma-spreading rate could be increased.
Correlations of Water Quality Parameters with Mutagenicity of Chlorinated Drinking Water Samples

Adverse health effects that may result from chronic exposure to mixtures of disinfection by-products (DBPs) present in drinking waters may be linked to both the types and concentrations of DBPs present. Depending on the characteristics of the source water and treatment processes used, both types and concentrations of DBPs found in drinking waters vary substantially. The composition of a drinking-water mixture also may change during distribution. This study evaluated the relationships between mutagenicity, using the Ames assay, and water quality parameters. The study included information on treatment, mutagenicity data, and water quality data for source waters, finished waters, and distribution samples collected from five full-scale drinking water treatment plants, which used chlorine exclusively for disinfection. Four of the plants used surface water sources and the fifth plant used groundwater. Correlations between mutagenicity and water quality parameters are presented. The highest correlation was obser...
Group divisible designs with two associate classes, and quadratic leaves of triple systems

Abstract In this paper, we consider group divisible designs with two associate classes, completely settling the existence problem for K 3 -designs of λ 1 K n ∨ λ 2 λ 1 K m when m = 2 and when λ 1 ≥ λ 2 . We also extend a classic result of Colbourn and Rosa on quadratic leaves, finding necessary and sufficient conditions for the existence of a K 3 -decomposition of λ K n − E ( Q ) , where Q is any 2-regular subgraph of K n .
Algebraic structure of open string interactions

Starting from the gauge-invariant equations of motion for the free open string we show how to generate interactions by analogy with the Yang-Mills system. We postulate non-Abelian transformation laws acting on the fields of the gauge-invariant free open-string theory. By demanding algebraic closure we then derive a set of consistency requirements and show that they lead to the construction of the minimal interacting equations which contain no cubic terms away from the physical gauge. We present explicit solutions to lowest interacting order for both vertices and structure functions.
Acetone Fluorescence as a Conserved Scalar Marker in a Laminar Methane/Air Diffusion Flame

The use of acetone seeding as a fluorescence marker for mixture fraction in a laminar methane/air diffusion flame has been investigated by Laser Induced Fluorescence (LIF). The 308 nm radiation from a XeCl excimer laser excited both the acetone and hydroxyl radical first electronic transitions in a flame fueled by methane doped with 8.5% acetone. Flame structure, as indicated by hydroxyl radical profiles, is not appreciably different in the seeded flame compared with the unseeded flame. The raw fluorescence images are corrected for collisional quenching to produce acetone concentration profiles. A satisfactory correlation between acetone mass fraction and mixture fraction, ξ, for the more fuel-rich regions of the flame is found. Acetone cannot be used in leaner regions because of thermal decomposition and slower diffusion for the dopant, with the former effect being more significant.
Structural optimization via a design space hierarchy

Mathematical programming techniques provide a general approach to automated structural design. An iterative method is proposed in which design is treated as a hierarchy of subproblems, one being locally constrained and the other being locally unconstrained. It is assumed that the design space is locally convex in the case of good initial designs and that the objective and constraint functions are continuous, with continuous first derivatives. A general design algorithm is outlined for finding a move direction which will decrease the value of the objective function while maintaining a feasible design. The case of one-dimensional search in a two-variable design space is discussed. Possible applications are discussed. A major feature of the proposed algorithm is its application to problems which are inherently ill-conditioned, such as design of structures for optimum geometry.
Front tracking in two and three dimensions

Abstract Front tracking is a method for solving conservation laws in which the evolution of discontinuities is determined through the solution of Riemann problems. This method often does not require highly refined grids, and it has no numerical diffusion. We show the success of this method through a comparison of simulations of the Richtmyer-Meshkov instability, an unstable material interface, with experimental data. Good simulations of such instabilities are notoriously difficult, and we also demonstrate for the same physical problem that grid orientations have no effect on the numerical solution. We also present the first results of our three-dimensional front tracking code by simulating an important aspect of the computer chip manufacturing process: material deposition and etching. Our two- and three-dimensional front tracking code is parallelized for MIMD architectures and runs on our 128 node Intel Paragon.
Synthesis of Block Copolymers Containing Pendant Carbazole Groups via Living Ring-Opening Metathesis Polymerization

A new carbazole-functionalized norbornene derivative, 5-[methylbis(N-carbazolyl)silyl]-2-norbornene, was polymerized via living ring-opening metathesis polymerization (ROMP) with RuCl2(CHPh)(PCy3)2...
A cohomological viewpoint on elementary school arithmetic

(2002). A Cohomological Viewpoint on Elementary School Arithmetic. The American Mathematical Monthly: Vol. 109, No. 9, pp. 796-805.
Increased venous proinflammatory gene expression and intimal hyperplasia in an aorto-caval fistula model in the rat.

We hypothesized that the venous limb of an arteriovenous (AV) fistula would evince up-regulation of genes relevant to vascular remodeling along with neointimal hyperplasia and relevant histological changes. Using the aorto-caval model of an AV fistula model in the rat, we demonstrate marked up-regulation in such proinflammatory genes as monocyte chemoattractant protein-1, plasminogen activator inhibitor-1, and endothelin-1, 2 weeks after the creation of the fistula. Neointimal hyperplasia occurred in variable degrees by 5 weeks after establishing the fistula, and by 16 weeks, such neointimal hyperplasia was progressive and pronounced; at this time point, abundant extracellular matrix was also observed. Smooth muscle cells were present in the hyperplastic neointima as evidenced by staining for α-smooth muscle actin; ultrastructurally, smooth muscle cells with a synthetic as well as a contractile phenotype were readily observed. Accumulation of extracellular matrix in the model at 16 weeks was accompanied by increased expression of transforming growth factor-β1 mRNA, the latter finding contrasting with the suppression of transforming growth factor-β1 mRNA observed in this model at 2 weeks. In summary, we describe marked up-regulation in proinflammatory genes and progressive neointimal formation in the venous vasculature in an AV fistula model in the rat. We suggest that such alteration in gene expression and histological injury, in conjunction with the relative simplicity of this model, offer a new approach in the study of such timely biological and clinically relevant phenomena as differential gene expression in response to hemodynamic forces, processes involved in vascular remodeling, mechanisms of injury in venous bypass grafts, and mechanisms of dysfunction of AV fistulae used in hemodialysis.
Hydrodynamic behavior of the Cape Fear River and estuarine system: A synthesis and observational investigation of discharge-salinity intrusion relationships

Abstract Transport of constituents in partially mixed estuaries depends on the relative strengths of dominant forcing mechanisms which may include tides, river input, and wind. In this study, we investigated the major physical mechanisms that influence the salinity structure in the Cape Fear River Estuary (CFRE), a partially mixed estuary that is representative of river-dominated estuaries along the southeast Atlantic coast of the U.S. Based on analysis of observed hydrographic and hydrodynamic data, we first describe differences in velocity, salinity, and stratification at along-channel sections of the estuary for relatively low-flow conditions. We then investigate the influence of river inflow on the salinity intrusion (defined by the 1-salinity contour near the bottom), based on six methods of choosing discharge in order to identify an appropriate means of incorporating flow history into the discharge value. Our analyses indicate: 1) 92 percent of the variability in the length of the salinity intrusion over a five-year period can be explained based on the Hydrologic Flood Method identified in this work, 2) the salinity intrusion depends more weakly on discharge than predicted by classic analytical relationships for exchange-dominated systems in which the intrusion varies with discharge to the power of (−1/3), and 3) intra-tidal and tidal-range differences based on a 29-day modulation significantly influence the salinity structure. Our results suggest that the salinity intrusion location is dependent upon the hydrologic “flood,” defined by a peak in the river-discharge hydrograph. The analysis indicates that the new method used to determine discharge in the CFRE can more accurately explain river inflow–salinity relationships than previously investigated methods. In river-estuary systems in which hydrologic flood peaks are large relative to base flow, we hypothesize the hydrologic flood model offers a useful tool for predicting the estuarine salinity response to river inflow.
An experimental test of the testosterone mediated oxidation handicap hypothesis in a wild bird

The oxidation handicap hypothesis (OHH) proposed that honesty in sexual signals is maintained when testosterone simultaneously promotes the development of elaborate signals and imposes an oxidative cost. Although there is evidence that testosterone enhances display traits in some cases, relatively few studies have tested the prediction that testosterone generates oxidative costs. We tested this prediction experimentally by administering testosterone (n=14) and control (n=14) implants to free-living common yellowthroat warblers (Geothlypis trichas) and quantifying testosterone and oxidative state before and 35±15days after implantation. We interpreted our experimental results in the context of a larger database of 83 unmanipulated males observed over five breeding seasons. In our observational data, testosterone was related to aspects of the carotenoid-based bib, but these relationships were age-dependent. Bib coloration was related to testosterone only for first time breeders, while bib size was positively and negatively associated with testosterone among experienced and inexperienced breeders, respectively. Two measures of oxidative metabolism-damage to DNA and total antioxidant capacity (TAC)-were unrelated to endogenous testosterone. Despite the correlation between endogenous testosterone and plumage, our experimental results failed to support the key prediction of the OHH. Testosterone treated males had higher levels of TAC upon recapture, but oxidative damage to DNA did not differ from controls. Because antioxidants can protect against the harmful effects of oxidative stress, one interpretation of our results is that males physiologically compensated for elevated testosterone, avoiding the honesty enforcing mechanism of the OHH. Taken together, our results suggest that testosterone is not a direct mediator of honest signaling in yellowthroats via its effects on oxidative stress.
Strong evidence for autosomal dominant inheritance of severe congenital neutropenia associated with ELA2 Mutations

Objective To investigate cases of severe congenital neutropenia (SCN) to ascertain SCN inheritance after determining that the same sperm donor was used by 4 different families to impregnate mothers. Study design Because the donor sperm was not available, alternative methods were used to determine whether the sperm donor transmitted SCN. DNA isolated from leukocytes was used to sequence the ELA2 gene in the affected children and their mothers. ELA2 was amplified by polymerase chain reaction (PCR), and the product was sequenced. PCR was also performed with genomic DNA from the mothers and affected children using a set of 22 microsatellite PCR primers on chromosomes 14 and 19 to establish linkage to the paternal allele. Results None of the mothers had a mutation in ELA2 , but all 5 affected children had the same mutation affecting the fourth exon at site S97L. Linkage mapping analysis confirmed that all affected children had the same paternal allele on chromosome 19, which contains ELA2 . Conclusions Our findings indicate that the father provided consistent haplotypes leading to the expression of SCN in all affected children, supporting an autosomal dominant inheritance in which ELA2 mutations occur.
Effect of a proprietary protein supplement on recovery indices following resistance exercise in strength/power athletes

The effect of 42 g of protein ingested pre- and post-exercise on recovery from an acute resistance exercise session was examined in 15 male strength/power athletes who were randomly divided into a supplement (SUP) or placebo (PL) group. Subjects reported to the Human Performance Laboratory (HPL) on four separate occasions (T1–T4). Maximal strength [one repetition-maximum (1-RM)] testing was performed during T1. During T2 subjects performed four sets of ten repetitions at 80% of their 1-RM in the squat, dead lift and barbell lunge exercises with 90 s of rest between each set. Blood draws occurred at baseline (BL), immediate and 15 min post-exercise to determine testosterone, cortisol and creatine kinase (CK) concentrations. Subjects reported back to the HPL 24 (T3) and 48 h (T4) post-exercise for a BL blood draw and to perform four sets of ten repetitions with 80% of 1-RM for the squat exercise only. No differences in the number of repetitions performed in the squat exercise were seen between the groups at T2. Relative to T2, PL performed significantly (P < 0.05) fewer repetitions than SUP at T3 and T4 (−9.5 ± 5.5 repetitions vs. −3.3 ± 3.6 during T3, respectively, and −10.5 ± 8.2 repetitions vs. −2.3 ± 2.9 repetitions during T4, respectively). No differences in hormonal measures were seen between the groups. CK concentrations were significantly (P < 0.05) elevated at T3 for both groups, but continued to elevate (P < 0.05) at T4 for PL only. No significant group differences were noted for CK at any time point. Results indicate that a proprietary protein SUP consumed before and after a resistance training session significantly contributes to improvements in exercise recovery 24 and 48 h post-exercise.
The association of preoperative breast magnetic resonance imaging and multiple breast surgeries among older women with early stage breast cancer

To evaluate the association between preoperative breast magnetic resonance imaging (MRI) utilization and the rate of multiple surgeries, and to investigate the extent of any variation of rates of multiple surgeries among physicians. We identified patients with stage 0, I, or II breast cancer diagnosed between 2002 and 2007 in the Surveillance, Epidemiology, and End Results-Medicare database. Using diagnosis and procedure codes, we defined that the initial treatment episode had ended when a gap in surgery occurred at least 90 days after primary surgery. Surgical procedures of partial mastectomy or mastectomy during the initial treatment period were calculated to identify patients who received multiple surgeries. Multilevel logistic regression models were used to identify patient- and physician-level predictors of multiple surgeries. Of 45,453 women with early stage breast cancer who were treated by 2,595 surgeons during the study period, 9,462 patients (20.8 %) received multiple breast surgeries; of these patients, 8,318 (87.9 %) underwent one additional surgery, 988 (10.4 %) received two additional surgeries, and 156 (1.6 %) received three or more additional surgeries. Among 2,997 (6.6 % of the entire cohort) women who underwent preoperative breast MRI evaluation, 770 received multiple breast surgeries. After we adjusted for patient and tumor characteristics associated with multiple surgeries, we found that the rate of multiple surgeries was not significantly different between the two groups with or without preoperative breast MRI. Furthermore, the median odds ratio of 2.0, corresponding with the median value of the relative odds of receiving multiple surgeries between two randomly chosen physicians after controlling for other confounders, indicated a large individual surgeon effect. Substantial variation was observed in the rates of multiple surgeries in women aged 66 and older with early stage breast cancer. Evidence does not support that preoperative breast MRI reduces the incidence of multiple surgeries.
Masculinity ideology, male identity, and romantic relationship quality among heterosexual and gay men.

This research assessed factors that may affect men’s romantic relationships. One hundred men (50 heterosexual and 50 gay) in the Northeast US completed measures that assessed masculinity ideology, male identity, and relationship quality. We examined whether the quality of heterosexual men’s romantic relationships differ from that of romantic relationships among gay men, and whether masculinity ideology and male identity are related to the quality of heterosexual and same-sex romantic relationships. Results indicated no differences between heterosexual and gay men in the perceived quality of romantic relationships. However, in both gay and heterosexual men, traditional masculinity ideology and a male identity characterized by a lack of psychological relatedness to other men were associated with lower quality romantic relationships.
Toward a reconciliation of "assimilation" and "pluralism": the interplay of acculturation and ethnic retention.

"The reconciliation between ?assimilation' and ?pluralism' is sought to help prevent further polarization among immigration researchers and is based mainly on two arguments. First, if assimilation and acculturation are distinguished, acculturation has proceeded more quickly than assimilation in both ?old' and ?new' immigrations. This reconciles traditional assimilationist theory with current pluralist--or ethnic retention--theory, which admits that acculturation (and accommodation) are occurring but without assimilation. Second, the reconciliation can also be advanced by the recognition that the researchers of the old and new immigrations have studied different generations of newcomers and have approached their research with ?outsider' and ?insider' values, respectively." The geographical focus is on the United States.
An intersection property for starshaped sets in the plane

Let ℱ be a family of compact starshaped sets in the plane. If every three and every two members of ℱ have a union which is connected and simply connected, then ∩{F:F in ℱ} is simply connected and nonempty. Of course, if every three and every two members of ℱ have a starshaped union, the same result holds.
Synthesis of hexalabeled thymine and thymidine

The synthesis of hexalabeled thymine and thymidine are described and field ionization mass spectra are recorded for these materials. Field ionization mass spectrometry is preferred in the utilization of multilabeled compounds as tracers in biomedical applications.
Mechanism of the carbonylation of dicyclopentadienylmolybdenum dihydride

Abstract The carbonylation of Cp2MoH2 proceeds through the intermediates Cp2MoCO, [Cp2Mo(H)CO] [CpMo(CO)3] (I) and CpMo(CO)3 to the final products [CpMo(CO)3]2 and CpMo(η3-C5H7)(CO)2. The formation of I in the carbonylation reaction has been shown to involve net hydride transfer, but an alternate synthesis has demonstrated the considerable proton basicity of Cp2MoCO. Since the net hydride transfer between Cp2MoH2 and [CpMo(CO)3]2 can be accelerated by production of metal centered radicals, the actual mechanism is not a simple two-electron process (H− transfer, but rather a sequence of one-electron steps.
A new twist on an old approach: A random-interaction approach for estimating rates of inter-group interaction

There are numerous instances in which researchers wish to measure the rate of intra- or inter-group interactions (whether positive or negative). When computing such measures as rates there is great uncertainty regarding the appropriate denominator: we analytically illustrate how the choice of the denominator when calculating such rates is not trivial and that some existing strategies create a built-in relationship between the computed rate and the group composition within the entity. Another strand of prior work only focused on the relative occurrence of intra- versus inter-group events, which does not account for the important theoretical possibility that both types of events might increase in certain social contexts. Our approach provides an advance over these earlier strategies as it allows one to take into account the relative frequency of interaction between members of different groups, but then translates this into per capita rates. We also provide an empirical example using data on inter- and intra-group robbery and aggravated assault events for block groups in a section of the city of Los Angeles to illustrate how our procedure works and to illustrate how other approaches can lead to dramatically different conclusions.
High-power single-mode antiresonant reflecting optical waveguide-type diode lasers

ARROW-type diode lasers show strong single-mode selectivity with stable beam operation to high powers (500 mW) due to the large built-in index profile. Triple-core ARROW lasers have potential for 1 W single-spatial mode operation. Preliminary results are 550 mW (diffraction- limited beam) from a 20 micron aperture triple-core ARROW laser fabricated using the InGaP based material system.
Inhibitors of Apoptosis Proteins in Injury and Disease

The inhibitor of apoptosis (IAP) gene family prevents cell death by binding to and inhibiting caspases. In addition to negatively regulating apoptosis, IAPs bind to signaling intermediates and receptors, and participate in diverse cellular functions. Here, we describe the physiological functions of IAPs and their participation in injury and disease processes.
“Specificity Determinants” Improve Therapeutic Indices of Two Antimicrobial Peptides Piscidin 1 and Dermaseptin S4 Against the Gram-negative Pathogens Acinetobacter baumannii and Pseudomonas aeruginosa

A new class of antimicrobial agents with lower rates of resistance and different targets is urgently needed because of the rapidly increasing resistance to classical antibiotics. Amphipathic cationic α-helical antimicrobial peptides (AMPs) represent such a class of compounds. In our previous studies, using a 26-residue de novo designed antimicrobial peptide, we proposed the concept of “specificity determinant(s)”: positively charged residue(s) in the center of the non-polar face of AMPs that could decrease hemolytic activity/toxicity but increase or maintain the same level of antimicrobial activity to increase dramatically the therapeutic index. In the current study, we used d-enantiomers of two AMPs, Piscidin 1 isolated from fish and dermaseptin S4 isolated from frog. We substituted different positions in the center of the hydrophobic face with one or two lysine residue(s) (one or two “specificity determinant(s)”). This simple modification not only maintained or improved antimicrobial activity against Gram-negative pathogens Acinetobacter baumannii (11 strains) and Pseudomonas aeruginosa (6 strains), but also dramatically decreased hemolytic activity of human red blood cells, as predicted. Therapeutic indices improved by 55-fold and 730-fold for piscidin 1 (I9K) and dermaseptin S4 (L7K, A14K), respectively, against A. baumannii. Similarly, the therapeutic indices improved 32-fold and 980-fold for piscidin 1 (I9K) and dermaseptin S4 (L7K, A14K), respectively, against P. aeruginosa.
Interfacial shear strength studies using the single-filament-composite test. Part II: A probability model and Monte Carlo simulation

A Monte Carlo simulation is developed to provide a foundation for interpreting experimental data from the single-filament-composite test. The main focus is on developing an improved procedure for arriving at a realistic value for the shear strength of the fiber-matrix interface, but it is also shown how the test may be used to characterize the strength distribution of fibers at a length scale much shorter than is achievable in standard tension tests. The simulation is based on the widely used Poisson/Weibull probability model for fiber failure that characterizes the strength in terms of the random flaws distributed along the fiber. The primary mechanical model for stress buildup at the fiber end is the same as that assumed by most authors and assumes a constant interfacial shear stress in this shear transfer zone reminiscent of a yielding plastic matrix. We also, however, consider a bilinear model that allows for a zone of debonding with a constant shear stress lower than in the primary “plastic” zone. Simulation results are cast in terms of nondimensional variables and tabulated to allow for wide applicability. Sample size and confidence interval issues are also discussed.
Sesquiterpenes from Cupressus macrocarpa foliage.

Abstract Ten sesquiterpenes, many with unusual carbon skeletons, were identified in foliage of Cupressus macrocarpa. These are (−)-10-epi-β-acoradiene; ent-widdra-2,4(14)-diene; (E)-iso-γ-bisabolene, i.e., (4E)-4-(1,5-dimethylhex-5-enylidene)-1-methylcyclohexene; (−)-cumacrene, i.e., (4S)-4-[(1R,2S)-2-isopropenyl-1-methylcyclobutyl]-1-methylcyclohexene; (−)-α-chamipinene, i.e., (1S,6S,7S)-2,2,6,8-tetramethyltricyclo[5.3.1.01,6]undec-8-ene; and five sesquiterpenes with a 3,3,4′-trimethyl-1,1′-bi(cyclohexyl) skeleton for which the trivial name macrocarpane is proposed. The possible single-enzyme biogenesis of these sesquiterpenes is discussed.
Spectral methods for the viscoelastic time‐dependent flow equations with applications to Taylor–Couette flow

SUMMARY The time evolution of finite amplitude axisymmetric perturbations (Taylor cells) to the purely azimuthal, viscoelastic, cylindrical Couette flow was numerically simulated. Two time integration numerical methods were developed, both based on a pseudospectral spatial approximation of the variables, efficiently implemented using fast Poisson solvers and optimal filtering routines. The first method, applicable for finite Re numbers, is based on a time-splitting integration with the divergence-free condition enforced through an influence matrix technique. The second one, is based on a semi-implicit time integration of the constitutive equation with both the continuity and the momentum equations enforced as constraints. Stability results for an upper convected Maxwell fluid were obtained for the supercritical bifurcations, either steady or time-periodic, developed after the onset of instabilities in the primary flow. At small elasticity values, E = De/Re, the time integration of finite amplitude disturbances confirms the stability of the single branch of steady Taylor cells. At intermediate E values the rotating wave family of time-periodic solutions developed at the onset of instability is stable, whereas the standing wave is found to be unstable. At high E values, and in particular for the limit of creeping flow (E= a), the present study shows that the rotating wave family is unstable and the standing (radial) wave is stable, in agreement with previous finite-element investigations. It is thus shown that spectral techniques provide a robust and computationally efficient method for the simulation of complex, non-linear, time-dependent viscoelastic flows.
Calcium mobilization is required for nuclear vesicle fusion in vitro: Implications for membrane traffic and IP3 receptor function

We studied the fusion of nuclear vesicles bound to chromatin in Xenopus egg extracts. Fusion was inhibited by 5 mM BAPTA, a Ca2+ buffer that suppresses cytosolic [Ca2+] gradients. The BAPTA-inhibited step in fusion was biochemically distinct from, and occurred later than, the GTP gamma S-sensitive step mediated by the monomeric GTPase, ADP-ribosylation factor. Exogenous inositol 1,4,5-trisphosphate (IP3), which triggers Ca2+ release from lumenal stores via IP3 receptors, stimulated fusion in the presence of BAPTA. This rescue was specific, because inositol 1,3,4-trisphosphate had no effect. Heparin, a potent antagonist of IP3 receptors, independently blocked fusion in an IP3-reversible manner. We suggest that phosphoinositide signaling may regulate nuclear vesicle fusion.
Convergent expansions for solutions to non-linear singular Cauchy problems

This article deals with Fuchsian type systems of the form $$\left( {t\frac{\partial }{{\partial t}} - L} \right)u = g\left( {t,y,u,\frac{{\partial u}}{{\partial y}}} \right)$$ with g(0, … 0) = 0, Δu,v,wg(0, 0, 0, 0) = 0. Here L is a fixed endomorphism, and g is analytic in all variable, including t. It is known from Baouendi-Goulaoic that, if no eigenvalue of L is a non-negative integer, such a system has a unique analytic solution (unique precisely because the kernel contains only nonsmooth functions). The aim of this article is complementary to this result: it is to describe this kernel. The main theorem states roughly that the generalized eigenspaces associated with eigenvalues of L of positive real parts parametrize the set of all solutions. The method of proof is by constructing a formal solution, and proving convergence inductively with the aid of majorizing series.
Temperature changes following iontophoretic injection of acetylcholine into the rostral hypothalamus of the rat.

Abstract A method is described for iontophoretic injection of acetylcholine into the central nervous system of experimental animals. A fall in body temperature occurred when acetylcholine was delivered into the rostral hypothalamic thermoregulatory centers of the rat, but not when the drug was introduced at other sites in the hypothalamus. Systemic injection of atropine prevented the hypothermic response to subsequently injected acetylcholine. These results support the concept that central control of body temperature involves cholinergic receptors in the thermoregulatory centers.
On the complexity and hardness of the steganography embedding problem

We analyze the complexity of the steganography problem and show that the decision version of the problem is NP-complete through transformation from the Knapsack problem. We also give a pseudo-polynomial time algorithm to optimally solve the steganography problem. This optimal algorithm can also be applied to image steganography.
Plasma volume changes with long-term beta-adrenergic blockade

Abstract Plasma volume was determined repeatedly before and during long-term propranolol therapy in 14 hypertensive patients, as well as after cessation and resumption of the same therapy in some of them. In no instance was plasma volume expanded by propranolol; in contrast, it was reduced by more than 8 per cent in over half of the patients, so that the average for the whole group was significantly lowered during therapy extending up to 9 months (p
Measurement of urea nitrogen and creatinine concentrations in peritoneal dialysate and other body fluids using the Vitros analyzer

Abstract Objectives: A majority of chemistry analyzers have separate modes for estimating urea nitrogen and creatinine in serum and urine because of significant differences in their concentration. As there is no defined mode for other biological fluids such as dialysis fluid, these can be run on either of the two modes. On Vitros (Clinical Ortho-Diagnostics, Rochester, NY) chemistry analyzer, we observed an overestimation in calculated creatinine clearance (CrCl) and Kt/V urea in some children that led us to investigate into methodology used for these assays. Design and methods: We measured urea nitrogen and creatinine on peritoneal dialysate effluent, pleural fluid and hemofiltration effluent on serum and urine modes of Vitros analyzer. Results: Vitros chemistry analyzer significantly overestimated urea nitrogen and creatinine in ‘urine’ mode on samples with low urea nitrogen and creatinine. Conclusions: Since peritoneal dialysate effluent has concentrations of urea nitrogen and creatinine comparable to serum; hence, it should be analyzed on ‘serum’ mode.
The flow due to the motion of an object through a non-diffusive stratified fluid confined between horizontal planes

Very slow translation of an object through a stratified fluid confined between horizontal planes causes a very long upstream wake just as in the case when the fluid is unbounded. If the Froude number is exceedingly small and the Reynolds number is not too small, the inviscid core of the wake is bounded by boundary and shear layers which merge into the core far upstream to make the entire upstream motion viscous. We present here a solution which is uniformly-valid upstream of the obstacle. The downstream motion for an object which is a semi-infinite rectangular prism is uniformly viscous dominated, and a solution may also be constructed in that region. We further show that no downstream-growing boundary layers are possible in any such small-Froude-number flow.