cssi/SciSciGPT-SciSciNet huggingface dataset:
Construction of a hybrid quadrupole/Fourier transform ion cyclotron resonance mass spectrometer for versatile MS/MS above 10 kDa.

Technological advancements including an open-cylindrical Penning trap with capacitively coupled ICR cell, selective ion accumulation with a resolving quadrupole, and a voltage gradient used during ion extraction from an octopole ion trap, have individually improved dynamic range and sensitivity in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS). Documented here is a new instrument utilizing these technologies toward the robust detection and fragmentation of biomolecules >10 kDa. Up to 55-fold enhancement in ion population by selective ion accumulation combined with 10- to 20- fold signal-to-noise improvement by application of a DC voltage gradient to an accumulation octopole during the ion transfer event offers improved signal-to-noise (or speed) of MS/MS experiments, for proteins from Methanococcus jannaschii and Saccharomyces cerevisiae whole cell lysates. After external quadrupole filtering with a 40 m/z window, three proteins were fragmented (and identified) in parallel from the database of Methanococcus jannaschii. Electron capture dissociation (ECD) of an intact yeast protein provides extensive sequence information resulting in a high degree of localization for an N-terminal acetylation. Hybrid fragmentation, infrared multiphoton dissociation (IRMPD) followed by low energy electrons (ECD), with the electron source located laterally off the z-axis and external to the magnet bore, presents a strategy for identification of proteins by means of the sequence tag approach. Automated implementation of diverse MSn approaches in a Q-FTMS instrument promises to help realize “top-down” proteomics in the future.
Recent advances in the analysis of polychlorinated biphenyls in environmental and biological media

Abstract Analytical advances in the detection, identification and quantification of polychlorinated biphenyl isomers (PCBs) are reviewed. High-resolution gas chromatography, with specific reference to capillary column development and support “phases”, methodologies, detector systems and the comparative advantages and limitations of each combination, is covered. Problems associated with instrument calibration, general non-availability of primary PCB standards and the use of secondary standards are discussed. Typical applications of these newer methods to environmental, biological and process stream samples are presented.
Effects of glyphosate on metabolism of phenolic compounds II. Influence on soluble hydroxyphenolic compound, free amino acid and soluble protein levels in dark-grown maize roots

Abstract Further evidence is given to evaluate the hypothesis that glyphosate (N-(phosphonomethyl)glycine)-induced phenylalanine ammonia-lyase (PAL) activity can lead to growth inhibition due to changes in the metabolism of phenolic compounds in dark-grown maize (Zea mays L.) seedlings. Total soluble hydroxyphenolics, total soluble protein, and the levels and composition of free amino acid pools in root tissues were measured at 12, 24, 48 and 72 h after treatment. Total soluble hydroxyphenolics increased on a fresh wt. basis and decreased on a per root basis in treated versus control tissues. In treated plants a disproportionate decrease in phenolic amino acid levels was found to be concomitant with decreases in soluble hydroxyphenolics and increases in extractable PAL activity. Total soluble protein per root did not change significantly during this time in the glyphosate treatment with respect to the control.
Domain integral formulation for stress intensity factor computation along curved three-dimensional interface cracks

New domain integrals for extracting mixed-mode stress intensity factors along curved, three-dimensional bimaterial interface cracks are derived. In the derivation, the asymptotic auxiliary fields for the plane problem of a bimaterial interface crack are imposed along a curved crack front. The general crack-tip interaction integral (a contour integral surrounding a point on the crack front which is evaluated in the limit as the contour is shrunk onto the crack tip) is then expressed in domain form which is more suitable for numerical computation. A consequence of imposing the auxiliary fields along a curved crack front is that the auxiliary stress fields do not satisfy equilibrium, and the auxiliary strain fields do not satisfy compatibility. The terms which arise due to the lack of equilibrium and compatibility are not sufficiently singular to contribute to the crack-tip interaction integral or to affect its path independence; however, these terms become important when domain integral representations are introduced, because they involve fields which are not asymptotically close to the crack tip. In order to compute the pointwise stress intensity factors along the crack front, the domain integrals are evaluated as a post-processing step in the finite element method. In the numerical results, it is demonstrated that it is crucial to incorporate the terms that arise due to lack of equilibrium and compatibility of the auxiliary fields, especially in regions where the local crack front curvature is high. In the paper, we present two numerical examples. As a benchmark, we first consider the problem of a penny-shaped interface crack embedded in a cylinder. The results for the complex stress intensity factor and phase angle are found to be in excellent agreement with the analytical solution. The problem of an elliptical crack embedded between two dissimilar isotropic materials is also considered, and the results are discussed.
An Optimum Aero-Design Process of Turbine Blades

With the development of the advanced technology, the combustion temperature is raised for increased efficiencies. At the same time, the turbine and compressor pressure ratio and the mass flow rate rise; thus causing turbine and compressor blades turning and blade lengths increase. Moreover, the high efficiency requirements had made the turbine and compressor blade design difficult. A turbine airfoil has been custom designed for many years, but an optimization for the section design in a three-dimensional consideration is still a challenge. For a compressor blade design, standard section cannot meet the modern compressor requirements. Modern compressor design has not only needs a custom designed section according to flow situation, but also needs three-dimensional optimizations. Therefore, a good blade design process is critical to the turbines and compressors. A blade design of the turbomachines is one of the important steps for a good turbomachine design. A blade design process not only directly influences the overall machine efficiency but also dramatically impact the design time and cost. In this study, a blade design and optimization procedure was proposed for both turbine and compressor blade design. A compressor blade design was used as a test case. It was shown that the current design process had more advantages than conventional design methodology.Copyright © 2002 by ASME
Analytical Modeling of Creep Behavior of Short Fiber Reinforced Ceramic Matrix Composites

This paper studies the high-temperature creep behavior of short-fiber- reinforced ceramic matrix composites. A unidirectional short-fiber composite model under off-axis tension is established and analyzed using a multiaxial creep constitutive relation and an advanced shear-lag method. Both the fiber and matrix are capable of carry ing axial and shear loads, and the fibers also creep at elevated temperatures. Power law be havior is assumed for the fiber and matrix creep constitutive relations under uniaxial load ing. The stress distributions in the fiber and matrix, and the composite creep rate as functions of applied stress have been determined. Parametric studies have been performed for the effects of fiber volume fraction and fiber/matrix interface sliding factor on compos ite creep rate.
An Acrobat Ant, Crematogaster obscurata (Hymenoptera: Formicidae), Poses an Unusual Conservation Question in the Florida Keys

A small population of the Neotropical acrobat ant Crematogaster obscurata has survived a series of hurricanes on West Summerland Key, Monroe County, Florida. This is the only known U.S. population of this apparently innocuous species. If the exotic status and limited range of the Florida population is confirmed, it would be prudent to attempt to eradicate it, using insecticidal baits applied to the trees where colonies occur. View this article in BioOne
Simulation and graphics on microcomputers

It is difficult to relate the output of a simulation model to the physical system it describes. Graphic representa tions of results can make simulations more credible and more interesting. On most large computers, how ever, there are software and hardware barriers between the user and graphical output. Microcomputers, on the other hand, are easy to use, and simple graphics are easy to produce without help from a programmer or systems specialist. Examples show bar charts, snap shots, dot plots, bit density plots, and contour plots of simulation results generated using an Atari 800 micro computer, a color television, and an Epson MX-80 printer (costing about $600) with graphics capability. All the user must do to obtain such plots is write short programs (less than 100 statements) in BASIC.
Riding in Cars with Boys: Elinor Ostrom's Adventures with the Police

More than forty years ago, Elinor Ostrom began her adventures with the police. In order to combat the conventional view that “bigger means better,” Ostrom pioneered a field work-based framework for measuring police services that utilized consumer surveys and thereby created a community-centered model of analysis for public services. In this paper, we contend that although Ostrom’s career demonstrated the importance of employing multiple methods, her most enduring contributions and legacy came from on-the-ground research. Her case studies and field work proved to be necessary for examining complex systems beyond the state-market dichotomy, and these methods of analysis should be defended as critical for inquiry into the variety of institutional arrangements.
McCoy rings and zero-divisors

We investigate relations between the McCoy property and other standard ring theoretic properties. For example, we prove that the McCoy property does not pass to power series rings. We also classify how the McCoy property behaves under direct products and direct sums. We prove that McCoy rings with 1 are Dedekind finite, but not necessarily Abelian. In the other direction, we prove that duo rings, and many semi-commutative rings, are McCoy. Degree variations are defined, studied, and classified. The McCoy property is shown to behave poorly with respect to Morita equivalence and (infinite) matrix constructions.
The Missing Geographic Dimension to Soil Taxonomy

Abstract The establishment of Soil Taxonomy as the official United States system of soil classification introduced a number of innovative concepts of significance to soil classification, soil survey, and soil geography. These concepts include the pedon, the polypedon, the taxadjunct, consociation, and redefinitions of existing concepts such as the soil complex and the soil association. However, examination of the application of Soil Taxonomy in a geographic context reveals fundamental deficiencies in its ability to portray landscape pattern in a manner that concisely and effectively conveys to map users the soil surveyor's knowledge of soil distributions. Some of these problems can be illustrated by examining soils formed on the interbedded shales, sandstones, and dolomites of the Rome formation in the Central Valley of Virginia. These soils fall within four separate soil orders, arranged in such intimate landscape patterns that Soil Taxonomy seems inadequate as a vehicle for describing their geographic c...
Physiologic and Pathologic Changes in Patients with Continuous-Flow Ventricular Assist Devices

The clinical use of the newer continuous-flow pumps for mechanical circulatory support have resulted in superior outcomes including significantly reduced complication rates with improved durability over first generation pulsatile design pumps. However, as with all new technology, the newer LVADs have introduced a different set of management issues, as well as a unique risk profile into the mechanical circulatory support arena that were previously absent or unimportant with pulsatile LVADs. These include the effects of continuous flow on the systemic circulation and end-organ function, risk of thromboembolism, and pump thrombosis related to contact bearings in the blood path, the possible increased incidence of gastrointestinal bleeding, and ventricular arrhythmias, as well as alterations in the unloading characteristics of continuous-flow devices. This manuscript overviews the physiologic and pathologic effects that are associated with continuous-flow pumps and their unique management issues and complications.
Stochastic Behavior of Phase Synchronization Index and Cross-Frequency Couplings in Epileptogenic Zones during Interictal Periods Measured with Scalp dEEG

The stochastic behavior of the phase synchronization index (SI) and cross-frequency couplings on different days during a hospital stay of three epileptic patients was studied for noninvasive localization of the epileptogenic areas from high density, 256-channel, scalp EEG (dEEG) recordings. The study was performed with short-duration (0-180 sec), seizure-free, epileptiform-free and spike-free interictal dEEG data on different days of three subjects. The seizure areas were localized with subdural recordings with an 8×8 macro-electrode grid array and strip electrodes. The study was performed in theta (3-7 Hz), alpha (7-12 Hz), beta (12-30 Hz) and low gamma (30-50 Hz) bands. A detrended fluctuation analysis was used to find the long range temporal correlations in the SI that reveals the stochastic behavior of the SI in a given time period. The phase synchronization was computed after taking Hilbert transform of the EEG data. Contour plots were constructed with 20 sec time-frames using a montage of the layout of 256 electrode positions. It was found that the stochastic behavior of the SI was higher in epileptogenic areas and in nearby areas on different days for each subject. The low gamma band was found to be the best to localize the epileptic sites. Also, a stable higher pattern of SI emerged after 60-120 seconds in the epileptogenic areas. The cross-frequency couplings of SI in theta-gamma, beta-gamma and alpha-gamma bands were decreased and spatial patterns were fragmented in epileptogenic areas. Combinations of an increase in the stochastic behavior of the SI and decrease in cross-frequency couplings are potential markers to assist in localizing epileptogenic areas. These findings suggest that it is possible to localize the epileptogenic areas noninvasively from a short-duration (~ 180 sec), seizure-free and spike-free interictal scalp dEEG recordings.
The Quack Has Become God

For the British book trade, one of the major by-products of the eighteenth-century advent of a commodity culture was an upswing in the intensity of its advertising efforts. Chief among the new marketing practices was the use of puffery, or insider reviewing, to create hype for new publications. So naturalized had puffery become by the early nineteenth century that many authors saw nothing ethically remiss in arranging for themselves or friends to review their own works. In fact, at some point in his or her career, nearly every major author of the Romantic period bene�ted from reviews penned by friends and literary allies. By the late 1820s, puffery had become so ubiquitous and shameless that several leading writers and critics, including Thomas Carlyle and Thomas Babington Macaulay, blamed corrupt reviewing practices for killing the nation9s literary tradition. The recent slump of the literary book trade, it was widely argued, was less the product of the �nancial "Crash of 1826" than of the vitiation of society9s tastes by a corrupt, self-interested reviewing establishment.
An Economic Evaluation Model for Product Design Decisions under Concurrent Engineering

ABSTRACT Since a major component of a product cost is highly affected by a design decision made at an early stage of a product life cycle, the optimal design decision is critical in competitive manufacturing environments. For such optimal design decision making, the philosophy of concurrent engineering has become popular. In this paper, we propose an integrated decision model in which decisions on product and process design are simultaneously performed through economic evaluation at each stage of decision making. We introduce a dynamic programming method to determine the optimal design decision which minimizes the product cost under the strategic constraints given. We then apply the proposed decision model together with the solution procedure to a printed circuit board (PCB) designing and manufacturing company to demonstrate the effectiveness of a concurrent design of product and process.
WiFi, LTE, or Both?: Measuring Multi-Homed Wireless Internet Performance

Over the past two or three years, wireless cellular networks have become faster than before, most notably due to the deployment of LTE, HSPA+, and other similar networks. LTE throughputs can reach many megabits per second and can even rival WiFi throughputs in some locations. This paper addresses a fundamental question confronting transport and application-layer protocol designers: which network should an application use? WiFi, LTE, or Multi-Path TCP (MPTCP) running over both? We compare LTE and WiFi for transfers of different sizes along both directions (i.e. the uplink and the downlink) using a crowd-sourced mobile application run by 750 users over 180 days in 16 different countries. We find that LTE outperforms WiFi 40\% of the time, which is a higher fraction than one might expect at first sight. We measure flow-level MPTCP performance and compare it with the performance of TCP running over exclusively WiFi or LTE in 20 different locations across 7 cities in the United States. For short flows, we find that MPTCP performs worse than regular TCP running over the faster link; further, selecting the correct network for the primary subflow in MPTCP is critical in achieving good performance. For long flows, however, selecting the proper MPTCP congestion control algorithm is equally important. To complement our flow-level analysis, we analyze the traffic patterns of several mobile apps, finding that apps can be categorized as "short-flow dominated" or "long-flow dominated". We then record and replay these patterns over emulated WiFi and LTE links. We find that application performance has a similar dependence on the choice of networks as flow-level performance: an application dominated by short flows sees little gain from MPTCP, while an application with longer flows can benefit much more from MPTCP --- if the application can pick the right network for the primary subflow and the right choice of MPTCP congestion control.
Squamous Cell Carcinoma of the External Auditory Canal: A Case Report

Squamous cell carcinoma of the temporal bone and external auditory canal is a rare tumor with a reported incidence of between 1 to 6 cases per million population per year. Because squamous cell carcinoma of the temporal bone and auditory canal is so rare, developing an adequate tumor staging system and treatment has been difficult. We present a case of squamous cell carcinoma of the external auditory canal in 65-year-old Hispanic female who presented with a 6-month history of right ear pain, 3-month history of serosanguineous right ear drainage, and symptoms of facial paralysis. Due to the extensive spread of her tumor into the middle ear at the time of diagnosis, her tumor was deemed unresectable and she received palliative chemotherapy and radiation therapy and was sent to Alice Hospice and died several weeks later.
Niche-Associated Activation of Rac Promotes the Asymmetric Division of Drosophila Female Germline Stem Cells

Background Drosophila female germline stem cells (GSCs) reside adjacent to a cellular niche that secretes Bone Morphogenetic Protein (BMP) ligands and anchors the GSCs through adherens junctions. The GSCs divide asymmetrically such that one daughter remains in the niche as a GSC, while the other is born away from the niche and differentiates. However, given that the BMP signal can be diffusible, it remains unclear how a local extracellular asymmetry is sufficient to result in a robust pattern of asymmetric division. Methods and Findings Here we show that GSCs are polarized with respect to the cellular niche. We first use a modified biosensor to demonstrate that the small GTPase Rac is asymmetrically activated within the GSC at the niche-GSC interface. Experiments using loss-of-function and gain-of-function mutations in Rac indicate that asymmetric Rac activity both localizes the microtubule binding protein Apc2 to orient one GSC centrosome at the niche-GSC interface during interphase and activates the Jun N-terminal kinase pathway to increase the ability of the GSC to respond to BMP ligands. Other processes act in concert with each function of Rac. Specifically, we demonstrate that the GSC cell cycle arrests at prometaphase if centrosomes are misoriented. Conclusions Thus, the GSCs, an adult stem cell present in a cellular niche, have a niche-associated polarity that couples control of the division plane with increased response to an extracellular maintenance signal. Other processes work in parallel with the Rac-mediated polarity to ensure a robust pattern of asymmetric division. We suggest that all adult stem cells likely employ multiple, independently acting mechanisms to ensure asymmetric division to maintain tissue homeostasis.
Does TATA matter? A structural exploration of the selectivity determinants in its complexes with TATA box-binding protein

The binding of the TATA box-binding protein (TBP) to a TATA sequence in DNA is essential for eukaryotic basal transcription. TBP binds in the minor groove of DNA, causing a large distortion of the DNA helix. Given the apparent stereochemical equivalence of AT and TA basepairs in the minor groove, DNA deformability must play a significant role in binding site selection, because not all AT-rich sequences are bound effectively by TBP. To gain insight into the precise role that the properties of the TATA sequence have in determining the specificity of the DNA substrates of TBP, the solution structure and dynamics of seven DNA dodecamers have been studied by using molecular dynamics simulations. The analysis of the structural properties of basepair steps in these TATA sequences suggests a reason for the preference for alternating pyrimidine-purine (YR) sequences, but indicates that these properties cannot be the sole determinant of the sequence specificity of TBP. Rather, recognition depends on the interplay between the inherent deformability of the DNA and steric complementarity at the molecular interface.
Adverse Selection in Retiree Prescription Drug Plans

The authors used claims data from a large U.S. employer that introduced changes in its medical and drug coverage offerings in 2002 for non-Medicare eligible retirees.
Subcutaneous Lidocaine Does Not Affect the Success Rate of Intravenous Access in Children Less than 24 Months of Age

Objective: To determine whether subcutaneous lidocaine (SQL), when used to decrease the pain of IV catheter insertion, adversely affects IV access in children <24 months of age. Methods: A historically controlled comparison of IV access successes with and without SQL in children <2 years of age was performed in a 30,000-annual-visit community hospital ED. On-site data collected at the time of IV placement included: patient age, weight, hydration status, number of attempts, and location of attempts. All patients had IV attempts made by the same emergency physician. Results: A total of 110 children, mean age 9.6 ± 6.9 months, were included in the study analysis. Of the 110, 70 had an IV catheter placed with no pretreatment, while 40 had SQL pretreatment. The average number of attempts for all patients was 1.36 ± 0.73, with 83 (75%) performed successfully in 1 attempt and 101 (91%) within 2 attempts. The mean numbers of attempts were similar for the control and SQL groups: 1.34 vs 1.40, respectively (p = 0.68), as were the proportions successful in 1 attempt (77% vs 73%; p = 0.58) and within 2 attempts (91% vs 90%; p = 0.84). Conclusion: SQL use prior to an IV attempt in children 2 years of age does not impact vascular access. A secondary finding was that vascular access with and without SQL in infants and small children generally can be accomplished in 1 attempt.
The Benchmark Cluster Reddening Project. I. Reddening Values for the Hyades, Coma, and Praesepe

From histories of reddening studies for the Hyades, Praesepe, and nearby field stars, it is concluded that reddening scholarship requires fundamental reform. The adopted protocol for the reformed version of scholarship includes (1) rigorous published foundations for reddening values, (2) explicit quality control of reddening techniques, (3) use of techniques with limited metallicity sensitivity, (4) explicit zero-point control for both input data and derived reddening values, (5) an explicit choice of a reddening zero point, and (6) adherence to statistical norms. It is argued that only limited use should be made of reddening values from (1) spectral types for F0 and later type stars, (2) UBV analysis of blanketed stars, and (3) certain published relations between reddening and distance. However, reddening values may be based safely on (1) polarization measurements, (2) comparisons of β and (R - I)C for F stars, and (3) Stromgren β analysis of A stars. For the Hyades and Coma, upper 95% confidence limits on E(B - V) are found to be ≤1.0 and ≤3.2 mmag, respectively. For Praesepe, the derived value of E(B - V) is 27 ± 4 mmag. The latter result is obtained after an allowance is made for the effects of an anomalous relation between b - y and (R - I)C in Praesepe A stars. A test of the possibility that differential stellar rotation causes the anomaly yields an inconclusive result. Adoption of the revised reddening value instead of the canonical value of zero yields an increase in the derived Praesepe distance modulus by 0.14 mag and a decrease in the derived cluster age by about 11%. In addition, by using published high-dispersion results, it is found that the value of [Fe/H] for Praesepe that is consistent with the derived reddening value is +0.01 ± 0.04 dex. Further results for Praesepe stars will be required for a definitive comparison of the Hyades and Praesepe metallicities.
A new genus of eomyid rodent (Mammalia) from the Eocene (Uintan-Duchesnean) of southern California

ABSTRACT A new genus of eomyid, Metanoiamys, is described from the Uintan of southern California. Two new species, M. agorus and M. marinus are also named. All Eocene species previously referred to “Namatomys” are included in Metanoiamys. Species of Metanoiamys increase in crown height and lophodonty of the cheek teeth through time, though no species lineages are recognizable. Metanoiamys represents the stem genus for the Namatomyini and possibly Eomyinae, but not for the entire Eomyidae.
Effect of α2 macroglobulin on some kinetic parameters of trypsin

1. Complex formation of trypsin with alpha2 macroglobulin results in marked changes of the Michaelis-Menten constant, pH optimum and sensitivity to ionic strength in a system using N-carbobenzoxy-glycylglycyl-L-arginine-2-naphthylamide as substrate. 2. In contrasts to the inhibition (50%) observed when alpha2 macroglobulin-bound trypsin is assayed under conditions optimal for the free enzyme, there is minimal reduction of activity when determinations are performed at a substrate concentration and pH optimal for the bound enzyme. 3. The changes in substrate concentration and ionic environment required for maximum activity of alpha2 macroglobulin-bound trypsin are similar to those observed with enzymes embedded in polyelectrolyte matrices and may reflect alterations in the microenvironment of the enzyme resulting from conformational changes of the macromolecule during interaction with trypsin. 4. Enzymatic activity of trypsin towards casein is greatly reduced by alpha2 macroglobulin, even under assay conditions optimal for the bound enzyme, confirming previous findings that access to the active center for high-molecular weight substrates is sterically hindered by alpha2 macroglobulin.
Non-covalent assembly of a photoswitchable surface.

A noncovalently bound multilayered thin film in which individual layers are linked by metal ligand interactions undergoes a photochemically initiated permanent change in surface wettability. The film consists of three separate layers: a SAM on gold of 4-[(10-mercaptodecyl)oxy]pyridine-2,6-dicarboxylic acid, a layer of Cu(II) ions that are deposited onto the SAM and bind symmetrically in the site provided by the two carboxylate groups and the pyridyl nitrogen atom, and a layer of cis-2,2‘-dipyridylethylene, which caps the Cu(II) layer by complexation through both pyridyl nitrogen atoms (Film I). Photoexcitation of the film in chloroform at 300 nm leads to substantial cis−trans isomerization as indicated by conductivity, impedance, grazing incidence IR, and contact angle measurements. The latter show a decrease in contact angle (increase in wettability) of 17°, which is attributed to exposure of both the underlying Cu(II) layer and one of the pyridyl ring nitrogen atoms following isomerization to the trans...
Meditations on Immediate Resistance

Inspired by a graduate seminar (led by the writer), this piece is structured as a series of meditations that perform, in style and in argument, that which they theorize: immediate resistance. Borrowing from performance and poststructuralist theory, immediate resistance names oppositional acts that mix body and mind to exceed ideological significance. As the writer performs in the piece, immediate resistance threatens to render the self dissonant, even immobilized by contradiction. The meditations’ form and content allow the writer to play with multivalenced, open-ended interpretive and writing practices. The meditations are written to be free standing (but resonant), pleasurable (but nonclimactic), and accessible (but not transparent). Like immediate resistance, they risk incoherence and a violation of “real politics.” It is hoped that the meditations may provoke further resistance—particularly critical practice and performative writing, which might unhinge the modernist logics that persist in neoliberal ...
Mass Modulation of Protein Dynamics Associated with Barrier Crossing in Purine Nucleoside Phosphorylase

The role of protein dynamics on different time scales in enzyme catalysis remains an area of active debate. The connection between enzyme dynamics on the femtosecond time scale and transition state formation has been demonstrated in human purine nucleoside phosphorylase (PNP) through the study of a mass-altered enzyme. Isotopic substitution in human PNP (heavy PNP) decreased the rate of on-enzyme chemistry but did not alter either the transition state structure or steady-state kinetic parameters. Here we investigate the underlying atomic motions associated with altered barrier crossing probability for heavy PNP. Transition path sampling was employed to illuminate the molecular differences between barrier crossing in light and heavy enzymes. The mass effect is apparent in promoting vibrations that polarize the N-ribosidic bond, and that promote the stability of the purine leaving group. These motions facilitate barrier crossing.
Models and mergers in mathematical ecology

Theory of Population Genetics and Evolutionary Ecology: An Introduction. By J. Roughgarden. Pp.576. (Collier-Macmillan: 1980.) $24.95, £15.95.
Multi-Phase 1 GHz Voltage Doubler Charge Pump in 32 nm Logic Process

A multi-phase 1 GHz charge pump in 32 nm logic process demonstrates a compact area (159 × 42 ?m2) for boosting supply voltage from twice the threshold voltage (2 Vth) to 3-4 Vth. Self contained clocking with metal-finger flying capacitors enable embedding voltage boost functionality in close proximity to digital logic for supplying low current Vmin requirement of state elements in logic blocks. Multi-phase operation with phase separation of the order of buffer delays avoids the need for a large storage reservoir capacitor. Special configuration of the pump stages to work in parallel enables a fast (5 ns) output transition from disable to enable state. The multi-phase pump operated as a 1 V to 2 V doubler with >5 mA output capability addresses the need for a gated power delivery solution for logic blocks having state-preservation Vmin requirements.
Using novel spatial mark–resight techniques to monitor resident Canada geese in a suburban environment

Context. Over the past two decades, an increase in the number of resident (non-migratory) Canada geese (Branta canadensis) in the United States has heightened the awareness of human–goose interactions. Aims. Accordingly, baseline demographic estimates for goose populations are needed to help better understand the ecology of Canada geese in suburban areas. Methods. As a basis for monitoring efforts, we estimated densities of adult resident Canada geese in a suburban environment by using a novel spatial mark–resight method. We resighted 763 neck- and leg-banded resident Canada geese two to three times per week in and around Greensboro, North Carolina, over an 18-month period (June 2008 – December 2009).Weestimatedthedensity,detectionprobabilities,proportionofmalegeeseinthepopulation,andthemovementsand home-rangeradiiofthegeesebyseason((post-moltI2008(16July–31October),post-moltII2008/2009(1November–31 January), breeding and nesting 2009 (1 February – 31 May), and post-molt I 2009). Additionally, we used estimates of the number of marked individuals to quantify apparent monthly survival. Keyresults.Goosedensitiesvariedbyseason,rangingfrom11.10individualsperkm 2 (s.e.=0.23)inbreeding/nestingto 16.02 individuals per km 2 (s.e.=0.34) in post-molt II. The 95% bivariate normal home-range radii ranged from 2.60 to 3.86kmformalesandfrom1.90to3.15kmforfemalesandfemalehomerangesweresmallerthanthoseofmalegeeseduring the breeding/nesting and post-molt II seasons. Apparent monthly survival across the study was high, ranging from 0.972 (s.e.=0.005) to 0.995 (s.e.=0.002). Conclusions. By using spatial mark–resight models, we determined that Canada goose density estimates varied seasonally. Nevertheless, the seasonal changes in density are reflective of the seasonal changes in behaviour and physiological requirements of geese. Implications. Although defining the state–space of spatial mark–resight models requires careful consideration, the techniquerepresentsapromisingnewtooltoestimateandmonitorthedensityoffree-rangingwildlife.Spatialmark–resight methodsprovidemanagerswithstatisticallyrobustpopulationestimatesandallowinsightintoanimalspaceusewithoutthe need to employ more costly methods (e.g. telemetry). Also, when repeated across seasons or other biologically important time periods, spatial mark–resight modelling techniques allow for inference about apparent survival.
TCP behavior across multihop wireless networks and the wired internet

Emerging wireless ad hoc networks find their most important applications in untethered, mobile, multihop scenarios where there is no wired infrastructure. Yet, when the wired infrastructure (say, the Internet) is within reach, opportunistic connections to Internet sites may be established across the multihop network to transfer files and update databases. These file transfers use TCP for reliability and congestion control. However, recent experiments with ad hoc, multihop 802.11 networks have exposed serious instabilities when TCP connections span both wired and wireless domains. In particular, some TCP connections capture the wireless channel and drive the throughput on other connections virtually to zero. This is most surprising in view of the fact that connections between 802.11 (single hop) wireless LAN stations and the Internet are well behaved. In fact they are routinely used in most Campuses, Businesses and Research Labs. This paper is an experimental study of the unstable behavior of TCP across 802.11 ad hoc networks and the wired Internet. We investigate the fairness issues of multiple TCP flows as well as the coexistence of TCP flows and video streams in the wired/wireless scenario. Detailed analysis of the measurement results is also presented. The paper will prove very valuable to future commercial and military ad hoc networks.
Laser technique for evaluating spall resistance of brittle coatings

A laser technique for evaluating the spall resistance of brittle coatings was demonstrated. The method utilizes laser heating to motivate the spall by generating compressive stress in the coating. Critical exposure to laser heating thereby causes spalling at defective regions of the coating (nondefective regions are apparently immune to spalling). The laser spall results were calibrated against indentation tests in conjunction with a spalling criterion based on a critical bending strain. 13 references.
The spectrum of severe preeclampsia: comparative analysis by HELLP (hemolysis, elevated liver enzyme levels, and low platelet count) syndrome classification.

Abstract Objective: This study was undertaken to explore the spectrum of maternal disease with a triple classification system of HELLP (hemolysis, elevated liver enzyme levels, and low platelet count) syndrome and compare these classes with severe preeclampsia without HELLP syndrome. Study Design: In this retrospective analytic study the pregnancies of 777 patients with class 1, 2, or 3 HELLP syndrome were compared and contrasted with those of 193 women with severe preeclampsia but without HELLP syndrome. Results: Eclampsia, epigastric pain, nausea and vomiting, significant proteinuria, major maternal morbidity, and stillbirth increased as HELLP syndrome worsened from class 3 to class 1. In contrast, headache and diastolic hypertension were more common among the significantly heavier patients with severe preeclampsia without HELLP syndrome. Approximately half of pregnancies complicated by class 1 HELLP syndrome exhibited significant maternal morbidity, compared with only 11% of those complicated by severe preeclampsia without HELLP syndrome. Although a significant trend was apparent in increasing levels of lactate dehydrogenase, aspartate aminotransferase, and uric acid as HELLP syndrome worsened, there was considerable variation within groups. Conclusion: Laboratory and clinical indices of disease severity in patients with severe preeclampsia or eclampsia generally were highest with class 1 HELLP syndrome and were lowest when HELLP syndrome was absent. Class 3 HELLP syndrome is considered a clinically significant transitional group. (Am J Obstet Gynecol 1999;180:1373-84.)
Clozapine and Electroconvulsive Therapy-Reply

In Reply.— Dr Fink states that 70% of the cases treated by the Clozaril Collaborative Study Group 1 were failures after 6 weeks of treatment and might be better assigned to a trial of ECT plus neuroleptic. The point of my letter was that my clinical experience with clozapine provides abundant evidence that a number of treatmentresistant schizophrenic patients who have not responded to clozapine by 6 weeks will respond, sometimes dramatically, at subsequent periods. In my view, such patients should not be considered clozapine failures if there is no improvement by 6 weeks, but rather as possible responders who have not yet had an adequate trial. In short, just as clozapine clearly differs from typical neuroleptics in efficacy and side effects, it also differs in time course. I strongly believe that it is erroneous to apply the customary 6week trial period used for typical neuroleptic drugs to clozapine, based on
Salt Feedback in the Adiabatic Overturning Circulation

The adiabatic overturning circulation is the part of the meridional overturning circulation that persists in the limit of vanishing diffusivity. Two conditions are required for the existence of the adiabatic overturning circulation: a high-latitude zonally reentrant channel subject to surface westerlies and a set of outcropping isopycnals shared between the channel and the opposite hemisphere. This paper examines how different buoyancy forcing regimes, particularly freshwater flux, affect the surface buoyancy distribution and the strengthoftheadiabaticoverturningcirculation.Withoutfreshwaterforcing,salinityisuniformandbuoyancy is determined by temperature only. In this case, the size of the shared isopycnal window is effectively fixed by thecouplingbetweenatmosphericandseasurfacetemperatures.Withfreshwaterforcing(appliedasasurface flux), the salinity, and thus the sea surface buoyancy and the size of the shared isopycnal window, is not specified by the atmospheric state alone. It is found that a salt‐advection feedback leads to surface buoyancy distributions that increase the size of the isopycnal window and strengthen the adiabatic overturning circulation. The strength of the feedback is controlled by processes in high latitudes—the southern channel, where the surface salinity is determined by a balancebetween freshwater input from the atmosphere, salt input from upwelling deep water, and freshwater export by Ekman transport; and the Northern Hemisphere, where the overturning and wind-driven transport in the thermocline advect salty water from the subtropics, mitigating the freshening effect of the surface freshwater flux. The freshwater budget in the channel region provides an estimate of the size of the isopycnal window.
Intraspecific variation in gene expression under prolonged drought in Piriqueta hybrids and their parental taxa.

Closely related lineages can possess phenotypic variation important for adaptation and the evolution of new species; a phenomenon that can be more clearly elucidated by studying hybrid generations. We compare variation in gene expression in response to drought for two taxa and advanced-generation hybrids of the Piriqueta cistoides ssp. caroliniana complex that differ in their levels of tolerance to water limitation. Drought treatments lasted 36 days, through four cycles of drought. Gene expression in drought and control treatments was assessed using heterologous hybridization to a Glycine max microarray. There was a predominance of down-regulated genes in response to sustained drought in all morphotypes. This pattern was more pronounced in the hybrids, which can exhibit greater drought tolerance under field and greenhouse conditions than the parental morphotypes. Expression response profiles were more similar between the hybrid and the drought-tolerant parental morphotype than they were between the hybrid and the parental morphotype that occurs in more mesic habitats. Predominant down-regulation of gene expression contrasts with studies of response to short-term drought and with studies of drought response in annual and non-drought-tolerant model species, and supports the results of a growing number of studies with other drought-tolerant perennial plants under prolonged drought. © 2010 Published by Elsevier Ltd.
Miura Wins Cray Award

Topics covered include Computer Society award winners, the CRA-W distributed mentor program, and the launching of a new student design competition.
Gender differences in symptoms, functioning and social support in patients at ultra-high risk for developing a psychotic disorder

Gender differences have been widely observed in the clinical presentation, psychosocial functioning and course of illness in first-episode and chronic patients suffering from schizophrenia. However, little is known about gender differences in the psychosis prodrome. This study investigated gender differences in symptoms, functioning and social support in individuals at ultra-high-risk for developing a psychotic disorder. Sixty-eight ultra-high-risk patients were assessed at baseline, and twenty-seven returned for follow-up assessments approximately 6 and 12 months later. Clinical symptoms and functioning were assessed by clinical interview; social support was measured using a self-report questionnaire. There were no gender differences in demographic variables, symptoms or functioning at baseline. Males were found to have significantly higher levels of negative symptoms and marginally lower levels of functioning when baseline and follow-up time points were considered collectively. Additionally, females reported higher levels of social support at baseline. Differences in negative symptoms were found to mediate differences in functioning between male and female patients. This study suggests that gender based differences in symptom presentation and functional outcome may predate conversion to psychosis. Follow-up studies should examine the relationship between symptoms, functioning and social support in this population.
Diffusional and accretional growth of water drops in a rising adiabatic parcel: effects of the turbulent collision kernel

Abstract. A large set of rising adiabatic parcel simulations is executed to investigate the combined diffusional and accretional growth of cloud droplets in maritime and continental conditions, and to assess the impact of enhanced droplet collisions due to small-scale cloud turbulence. The microphysical model applies the droplet number density function to represent spectral evolution of cloud and rain/drizzle drops, and various numbers of bins in the numerical implementation, ranging from 40 to 320. Simulations are performed applying two traditional gravitational collection kernels and two kernels representing collisions of cloud droplets in the turbulent environment, with turbulent kinetic energy dissipation rates of 100 and 400 cm2 s−3. The overall result is that the rain initiation time significantly depends on the number of bins used, with earlier initiation of rain when the number of bins is low. This is explained as a combination of the increase of the width of activated droplet spectrum and enhanced numerical spreading of the spectrum during diffusional and collisional growth when the number of model bins is low. Simulations applying around 300 bins seem to produce rain at times which no longer depend on the number of bins, but the activation spectra are unrealistically narrow. These results call for an improved representation of droplet activation in numerical models of the type used in this study. Despite the numerical effects that impact the rain initiation time in different simulations, the turbulent speedup factor, the ratio of the rain initiation time for the turbulent collection kernel and the corresponding time for the gravitational kernel, is approximately independent of aerosol characteristics, parcel vertical velocity, and the number of bins used in the numerical model. The turbulent speedup factor is in the range 0.75–0.85 and 0.60–0.75 for the turbulent kinetic energy dissipation rates of 100 and 400 cm2 s−3, respectively.
A frailty model of segregation analysis: understanding the familial transmission of alcoholism.

Summary. Coupled with environmental factors, genes contribute to numerous human diseases and traits. While there are many epidemiological methods to assess the familial clustering of traits, few are flexible enough to accommodate interactions between covariates and familial factors. In this paper, we propose and develop a frailty model that establishes an integrated framework to evaluate familial transmission of a disease by controlling for covariate effects and conveniently testing the interactions between covariates and familial factors. We also present a peeling algorithm that dramatically reduces the computational burden. This frailty model is employed to examine the familial transmission of major subtypes of alcoholism, namely, alcohol abuse and dependence. We conclude that alcohol dependence is strongly familial whereas alcohol abuse expresses a marginally significant pattern of familial transmission. Moreover, females manifest alcoholism at a lower threshold, and there is no sex-specific familial transmission of alcoholism after adjustment for the threshold effect.