cssi/SciSciGPT-SciSciNet huggingface dataset:
The effects of models of aerosol hygroscopicity on the apportionment of extinction

Abstract The role that aerosols play in climate forcing and visibility issues has been the subject of research for several decades. Recent research efforts have focused on assessing the contribution of individual species to scattering and absorption under ambient conditions and on how scattering and absorption change as one or more species are removed from the atmosphere. A key concern is the distribution of water among aerosols as a function of mixing assumptions. As an illustrative and relevant example, we examine the roles of sulfates and organics in visibility and climate forcing, and in particular, the implications of assumptions regarding hygroscopic growth behavior upon the assignment of mass-scattering efficiencies to these species. We demonstrate that the total scattering computed for an aerosol sample is relatively insensitive to the choice of internal or external mixture, and can be insensitive to the exact formulation of the hygroscopic growth of the sample. Since the atmospheric aerosol is generally a complex mixture of chemical species, with the precise distribution of species on a particle-by-particle basis not known, the use of semi-empirical models of multicomponent aerosol hygroscopicity is appropriate for the calculation of atmospheric aerosol scattering and/or extinction, particularly since these details appear to be unimportant in most cases. In contrast, the apportionment of percentages of the total scattering to individual chemical species is quite sensitive to the choice of assumption regarding the aerosol microphysical structure. The use of semi-empirical hygroscopic growth models for computing the change in species scattering efficiency can lead to incorrect predictions in the limit of the complete removal of all but one chemical component. We propose a model that invokes the Zdanovskii, Stokes, and Robinson (ZSR) assumptions for the water content of multicomponent mixtures, and demonstrate that this method both approximates the predictions of generally accepted, semi-empirical models and asymptotically approaches the correct single-species scattering contributions upon removal of species. Efficiencies computed with this model can differ significantly from those predicted using the semi-empirical approach.
Purification of canine surfactant-associated glycoproteins A. Identification of a collagenase-resistant domain.

A procedure for purification of surfactant-associated glycoproteins A from canine surfactant was established utilizing preparative isoelectric focusing as a major purification step in absence of detergents. The proteins migrated as charge trains, isoelectric points 4.2–5.0. Unglycosylated forms of surfactant-associated protein A1 (26 kDa) and glycoproteins A2 and A3 (32–36 kDa) were identified by silver-staining and immunoblot analysis. These forms were demonstrated to be identical polypeptides by fingerprint analysis of 125I-labeled peptides generated by tryptic-chymotryptic digests of the iodinated proteins. Size and charge heterogeneity were related to varying amounts of N-linked complex carbohydrates, including sialic acid, which were sensitive to endoglycosidase F and neuraminidase but resistant to endoglycosidase H. A collagenase-sensitive region was demonstrated which was required for sulfhydryl-dependent oligomerization of the molecule. Collagenase treatment resulted in removal of approx. 10 kDa from the glycoprotein molecule. Collagenase-resistant fragments of 21–23 kDa migrated with carbohydrate-dependent size and charge heterogeneity and were reduced to 16 kDa by endoglycosidase F. Amino acid composition of the surfactant glycoproteins demonstrated high glycine content which was diminished after digestion with collagenase. Several glycine-rich tryptic peptides were isolated by reverse-phase chromatography. Partial sequence information shows Gly-X-Y repeat sequences containing hydroxyproline residues. The major canine surfactant-associated proteins, glycoproteins A contain complex-type N-linked carbohydrate. In addition, a separate collagen-like peptide domain is present and is required for sulfhydryl-dependent oligomerization.
Efficacy and toxicity of radiation in preparative regimens for pediatric stem cell transplantation. I: Clinical applications and therapeutic effects

Here, we review the role of total body irradiation in the treatment of children with bone marrow transplantation, as well as alternative sources of stem cells. We were unable to demonstrate any clear superiority of TBI-containing preparative regimens, but we were able to find a few definitive reports of significantly enhanced toxicity or important variations in control of the underlying primary diseases, in comparing TBI-based regimens, with those containing only chemotherapy.
Rousseau on the foundation of national cultures

Rousseau is a liberal or a a totalitarian or whether he is simply confused, attempting to reconcile the irreconcilable
Expression of PDGF and their receptors in human retinal pigment epithelial cells and fibroblasts: Regulation by TGF-β

Platelet derived growth factors (PDGF) are known to be associated with vitreoretinal disorders such as proliferative vitreoretinopathy (PVR). We have studied the expression of PDGF and their receptors in human retinal pigment epithelial cells (HRPE) and choroid fibroblasts (HCHF), and the regulation of PDGF and its receptors by various cytokines and growth factors. RT-PCR analyses showed enhanced expression of PDGF-A and PDGF-B mRNA in HRPE treated with TGF-beta, but not with other cytokines. A minimal increase was observed in PDGF-A mRNA in TGF-beta treated HCHF cells. PDGF-R alpha mRNA, which was expressed prominently in HCHF and at very low levels in HRPE, was not affected by any of the agents. PDGF-R beta was not detectable in either HRPE or HCHF. HRPE secreted PDGF-AA and AB constitutively, and this secretion was significantly enhanced by TGF-beta. In contrast, HCHF cultures did not secrete detectable levels of any of the three isoforms of PDGF (AA, AB, BB). All three human recombinant PDGF isoforms enhanced HCHF cell proliferation significantly, while only a minimal increase was observed in HRPE. PDGF isoforms also induced HCHF cell elongation and promoted migration of HCHF in an in vitro wound assay. The results presented in this study demonstrate that TGF-beta activated RPE cells produce PDGF that may act on fibroblasts and other mesenchyme derived cells which express PDGF receptors. These studies indicate that the promotion of the proliferation and migration of mesenchymal cells by RPE cell derived PDGF may facilitate the formation of fibrovascular tissues associated with PVR.
Nietzsche's Tragic Realism

Whether in the service of aristocratic radicalism or radical democracy, Nietzsche's political thought has most often been associated with transformation rather than limitations. This paper argues that Nietzsche offers a realism that presents politics as driven by grand aspirations and bound by tragic limitations. Nietzsche draws on Thucydides as a source for a realism that is neither reductionist nor transformative, but rather looks to the grandest of human aspirations and the limits to those aspirations. The paper analyzes Nietzsche's treatment of the character of modern idealism, the source of conflicting values, the effects of liberalism, and the consequences of democratic modernity in order to flesh out his tragic realism. Rather than advocating the tyrannical decay he expects in the short term, Nietzsche points the way to a new politics shaped by grander goals and more moderate expectations than the idealistic leveling of modernity.
Inflammatory cytokines alter human gallbladder epithelial cell absorption/secretion

Gallbladder inflammation is an early feature of gallstone formation in animal models. The inflammatory response is associated with increases in myeloperoxidase and interleukin (IL)-l activities in the gallbladder wall. The present studies were designed to determine whether inflammatory cytokines directly affect gallbladder epithelial cell absorptive function. Studies were performed using cultured human gallbladder epithelial cells derived from a well-differentiated gallbladder carcinoma. Confluent monolayers were exposed to interleukin-1 (IL-lα), lL-lα plus its specific receptor inhibitor II.-Ira, tumor necrosis factor (TNT-α), lipopolysaccharide, or prostaglandin E2. Unidirectional sodium and chloride fluxes were measured and used to calculate net ion fluxes. Compared to control monolayers, lipopolysaccharide, prostaglandin E2, IL-lα, and TNF-α decreased mucosal-to-serosal and net sodium and chloride fluxes and increased scrosal-to-mucosal movement of sodium and unmeasured ions. The effects of IL-lα were completely inhibited by its specific receptor antagonist IL-lra. Similar to the proinflammatory agents lipopolysaccharide and prostaglandin E2, the inflammatory cytokines IL-lα and TNF-α directly affected gallbladder epithelial cell absorptive function. Because normal gallbladder absorptive function is protective against gallstone formation, alterations in absorptive function due to inflammation in the gallbladder wall may play a role in gallstone pathogenesis.
Are Prisoner Characteristics Associated with Therapeutic Community Treatment Process

The relationship between prisoner client characteristics and Therapeutic Community treatment process was examined in a male program (N = 164) and a female program (N = 195). Analyses were based on client reports on a multidimensional measure of treatment process and administrative data. Prisoner clients who are older or are poly-substance users had better Community Environment scores. Clients with children and fewer lifetime arrests had better scores on Personal Development and Change. Treatment process scores were comparable for clients in the female program and the male program. However, the association of treatment process with client characteristics appears stronger in the male program.
Sertraline-induced desensitization of the serotonin 5HT-2 receptor transmembrane signaling system.

Sertraline is a new, selective serotonin (5HT) uptake inhibitor with antidepressant activity. The effect of chronic administration of sertraline on 5HT-2 receptors in rat cortex was compared with that of the tricyclic antidepressant, amitriptyline. 5HT-2 receptors were evaluated in binding assays using [3H]-ketanserin and in functional assays of transmembrane signaling, hydrolysis of phosphoinositides. The daily injection of 17 mg/kg sertraline induced a desensitization of 5HT-2-mediated phosphoinositide hydrolysis after 28, but not 21, days. The administration of 1.2 mg/kg/day via continuous release pumps caused a more rapid desensitization. Amitriptyline administered chronically also produced a desensitization of the 5HT-2-mediated phosphoinositide hydrolysis response. A decrease in the density of 5HT-2 binding sites accompanies the functional desensitization after amitriptyline, but changes in 5HT-2 binding sites were not detected after chronic sertraline administration. Studies of the mechanism of action of sertraline show that the desensitization of the phosphoinositide hydrolysis response is homologous in nature, and that it is not secondary to changes in the synthesis of precursor lipids. Other possibilities such as alterations in coupling efficiency or in the activity of effector enzymes are currently being considered. The present results suggest a new postsynaptic action of antidepressant drugs at central 5HT-2 receptors (i.e., changes in 5HT-2 signal transduction at a site distal to the cell surface binding site) and illustrate the importance of studies of receptor signaling pathways to complement radioligand binding.
Alteration in surface muscle electrical anisotropy in the rat SOD1 model of amyotrophic lateral sclerosis

Objective To evaluate the effects of progressive neurogenic change on surface-measured anisotropy via study in the rat superoxide dismutase 1 (SOD1) G93A amyotrophic lateral sclerosis (ALS) model.
Surface polaritons in LO-phonon-plasmon coupled systems in semiconductors

Surface polaritons in an LO-phonon-plasmon coupled system are studied in cylindrical and semi-infinite geometries. Characters of the dispersion relation of the surface polaritons are very different from the case of high carrier electron density and for the case of low density. With electron current the surface polaritons are destabilized in the low-density regime, while they remain stable in the high-density regime.
Adaptive edge-following force control of an industrial robot

Abstract Control of tool-workpiece interaction force is of vital importance in automated assembly. Using a simple linear continuous model of an edge-following system to predict the appropriate accomodation gains in a force control loop, previous work has shown that force control by accomodation is feasible. Following up this work, this paper describes the analysis, simulation and implementation of an adaptive force control in a two-dimensional edge-following task with a PUMA 560 robot and wrist force sensor. First, a discrete-time model of an edge-following system is developed and then used as the plant; second, a model reference adaptive control (MRAC) scheme is applied to achieve both tracking and regulation purposes. The reference (tracking) model can be determined by experimental reference input and desired model output information; the reference (regulation) model can be obtained by simulation to smooth out the plant output and improve the augmented filtered plant-model error. Study is done on the values of the adaptation gains in the adaptive mechanism, and hence can be adjusted to insure the best plant output performance.
Rule-based management for simulation in agricultural decision support systems

Abstract Rule-based management systems can offer the farmer or consultant the opportunity to better approximate current or proposed management options, especially as they relate to dynamic conditions in farm fields and across the whole farm. Most existing attempts at rule-based management within simulation-oriented agricultural decision support systems (DSS) involve limited extension of fixed management dates in response to environmental conditions, or involve rules for implementing limited management events such as fertilizer applications or irrigations. A comprehensive rule-based management system for agricultural DSS was developed that allows simulated management events to occur in response to flexible producer-defined rules and to weather and management induced changes in the soil–crop system over time and space. The system provides a simple, English-based rules language, a rules development editor, and software to parse and interpret these rules and provide linkages to application DSS software packages such as Great Plains Framework for Agricultural Resource Management (GPFARM). Rules can be quickly and easily developed that cover management activities for individual management units (MUs) or groups of MUs. Feedback to the simulation package at each time step provides for generation of site- and time-specific management events across the application. Tests of the rule-based system on: wheat ( Triticum aestivum L.), corn ( Zea mays L.), fallow and wheat–fallow crop rotations used in eastern Colorado showed that management events were simulated within the correct time windows and in the proper sequence. Dates for simulated events varied as expected across each rotational cycle as a function of temporal conditions. Additional work is anticipated to allow dynamic calculation of event attributes, capture and implementation of producer time priorities, and a simplified menu system for the rule editor.
The IL-33/ST2 pathway: therapeutic target and novel biomarker

For many years, the interleukin-1 receptor family member ST2 was an orphan receptor that was studied in the context of inflammatory and autoimmune disease. However, in 2005, a new cytokine — interleukin-33 (IL-33) — was identified as a functional ligand for ST2. IL-33/ST2 signalling is involved in T-cell mediated immune responses, but more recently, an unanticipated role in cardiovascular disease has been demonstrated. IL-33/ST2 not only represents a promising cardiovascular biomarker but also a novel mechanism of intramyocardial fibroblast–cardiomyocyte communication that may prove to be a therapeutic target for the prevention of heart failure.
Antiemetics for acute gastroenteritis in children.

Purpose of reviewThe alleviation of vomiting due to gastroenteritis in children can help promote oral rehydration and prevent medical visits for dehydration.Recent findingsRecent randomized, placebo-controlled trials of newer antiemetics, such as serotonin antagonists like ondansetron, have demonstr
Zonal analysis of phospholipids in the epiphyseal cartilage and bone of normal and rachitic chickens and pigs.

The effect of various degrees of simple, vitamin D-deficient rickets on the levels, composition and extractability of phospholipids from calcifying and soft tissues was studied in chickens and pigs. A variety of effects of rickets on the phospholipid composition of the calcifying tissues were detected; there was little change in the soft tissues. The quantitative effects on the lipid concentration of rachitic hard tissues were variable from zone to zone and appeared to reflect variations in other tissue constituents. However, the qualitative differences indicated a direct effect on specific phospholipids. Acidic phospholipids displayed the greatest percentage change, although numerous statistically-significant changes were also seen in the neutral phospholipids. Tissue zones displaying the greatest change in phospholipid composition in rickets were proliferating and hypertrophic cartilage, and cancellous bone, with calcified cartilage showing the least effect. Rickets also reduced the extractability of certain acidic and neutral phospholipids from zones of early mineralization. These findings are interpreted as indicating the presence of elevated levels of phospholipid complexed with calcium phosphate in rachitic tissue, presumably due to the blockage of normal mineralization.
Local structure of ionic solid solutions: Extended x-ray-absorption fine-structure study.

The first-neighbor distances in the ionically bonded rocksalt-structured solid solutions (${\mathrm{K}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Rb}}_{\mathrm{x}}$)Br and Rb(${\mathrm{Br}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{I}}_{\mathrm{x}}$) differ substantially from the average, or virtual-crystal, distance. There is, nonetheless, a significant variation in the first-neighbor distances with composition, indicating that the Pauling concept of the conservation of ionic radii is not valid. This change, relative to the change in the lattice constant, is about twice as large as that observed in covalently bonded, zincblende-structured solid solutions, resulting from the different crystal structures for these two alloy systems.
Auto-Walksat: A Self-Tuning Implementation of Walksat

Abstract Abstract Stochastic search algorithms have proven to be very fast at solving many satisfiability problems [2,3,8]. The nature of their search requires careful parameter tuning to maximize performance, but depending on the problem and the details of the stochastic algorithm, the correct tuning may be difficult to ascertain [9]. In this paper we introduce Auto-Walksat , a general algorithm which automatically tunes any variant of the Walksat family of stochastic satisfiability solvers. We demonstrate Auto-Walksat's success in tuning Walksat-SKC to the DIMACS benchmark problems with negligible additional overhead.
A Quasi-shrinking rectangle algorithm for complex zeros of a function

Presented here is a quasi-shrinking rectangle algorithm that computes a complex zero of a polynomial or transcendental function. This method has been implemented using several quasi-random number sequences and the results of several test examples are presented. The performance of this algorithm is based on a ranked comparison of relative error and time complexity versus several pseudo-random number sequences.
Isolation and characterization of the cyanogen bromide peptides from the α1 and α2 chains of soluble bovine striated muscle collagen

Abstract 1. 1.The α1 and α2 chains of soluble bovine striated muscle collagen were cleaved with CNBr and the resulting peptides separated and purified by a combination of ion-exchange and molecular sieve chromatography. 2. 2.The finding of eight peptides from the α1 chain and six from the α2 chain was consistent with the methionine content of these chains. 3. 3.The amino acid compositions and molecular weights of the peptides accounted for all the amino acids and the molecular weight of the intact chains. 4. 4.Only minor variations were discernible in the amino acid composition of the CNBr peptides from soluble muscle collagen and that reported for other mammalian and avian soluble collagens. 5. 5.Similar to primate collagen, a methionine substitution in the NH 2 -terminal sequences of the α1 chain resulted in the elimination of the NH 2 -terminal dipeptide, α1-CBo, which is present in rat tendon and chick soluble collagen. 6. 6.The soluble muscle collagen α1 also contained a single α1-CB6 peptide rather than the α1-CB6A and α1-CB6B peptides found in chick skin and bone. 7. 7.The presence of the aldehyde form of the NH 2 -terminal nonhelical peptides from the α1 and α2 chains of soluble muscle collagen suggests that lysyl residues are involved in the formation of intramolecular cross-links as has been shown for rat and chick soluble collagens.
COMPARATIVE VALIDITY OF HARRIS AND KOPPITZ SCORING SYSTEMS FOR HUMAN-FIGURE DRAWINGS

This study examined the comparative validity of the Harris and Koppitz scoring systems for human-figure drawings by 50 boys who were administered these tests as part of a regular psychological eval...
How International Students Can Benefit from a Web-Based College Orientation.

As colleges and universities increasingly seek to recruit more international students, they must also look for ways of preparing those students to meet the special challenges of undertaking a new academic experience in a foreign environment. One way to prepare students is by using Web-based orientation.
On the dynamic behavior of continuous stirred tank reactors

Abstract The types of dynamic behavior possible for a single first order reaction carried out in a stirred tank reaction are classified according to values of the parameters and plots in parameter space used to define the various possibilites. Analytic criteria are developed which predict the existence and stability character of limit cycles as a function of the system parameters. The types of dynamic behavior predicted are illustrated by numerical computation of the temperature and concentration trajectories. Several kinds of new jump phenomena for this problem are observed and explained in terms of the parameter space plots. The theory and analysis methods can be easily generalized to other types of reaction systems.
Slotted bolted connection energy dissipators

Abstract Slotted Bolted Connections (SBCs) are modified bolted connections designed to dissipate energy through friction during rectilinear tension and compression loading cycles. Experimental results on two types of SBCs are reported. In one type, friction occurs between clean mill scale steel surfaces; in the other, friction is between clean mill scale steel and brass surfaces. The behavior of connections with brass on steel frictional surfaces is found to be more uniform and simpler to model analytically than that with steel on steel surfaces. These connections maintain essentially constant slip force, and unlike those with steel on steel surfaces, require minimal overstrength of the system in design. The frictional mechanisms giving rise to the observed behavior are explained. As an example of application a one story diagonally braced frame was designed and its behavior determined for four different earthquakes. Experimental results are presented for the fabricated SBC for this frame subjected consecu...
ShcA mediates the dominant pathway to extracellular signal-regulated kinase activation during early thymic development.

During thymic development, the β selection checkpoint is regulated by pre-T-cell receptor-initiated signals. Progression through this checkpoint is influenced by phosphorylation and activation of the serine/threonine kinases extracellular signal-regulated kinase 1 (ERK1) and ERK2, but the in vivo relevance of specific upstream players leading to ERK activation is not known. Here, using mice with a conditional loss of the shc1 gene or expressing mutants of ShcA, we demonstrate that the adapter protein ShcA is responsible for up to 70% of ERK activation in double-negative (DN) thymocytes in vivo and ex vivo. We also identify two specific tyrosines on ShcA that promote ERK phosphorylation in vivo, and mice expressing ShcA with mutations of these tyrosines show impaired DN thymocyte development. This work provides the first in vivo demonstration of the relative requirement of upstream adapters in controlling ERK activation during β selection and suggests a dominant role for ShcA.
The Effect of Visual Effort upon the Heart-Rate

Resume Les faits importants montres par cette enquěte sont (1) que la vitesse du coeur est devenue progressivement plus petite comme la duree de la tǎche visuelle (la lecture) est devenue plus longue et (2) que cette decroissance de la vitesse du coeur a ete plus grande sous une bougie-pied que sous 100 bougies-pied. L'analyse statistique des donnees experimentales a indique que ces effets ont ete reels et signifiants. On presente de l'evidence qui indique que la decroissance de la vitesse du coeur a ete due a l'effort visuel et non pas a une relation psychologique possible entre l'eclairement faible et la relaxation ou d'autres facteurs non controles. Le fait qu'une decroissance relativement grande de la vitesse du coeur a ete observee sous la plus petite intensite de l'eclairement mais non pas sous la plus grande a ete interprete comme une indication que les processus sensoriels ont ete anormalement surmenes dans la premier cas. Les decroissances de la vitesse du coeur ne sont pas considerees importante...
Medical student perception of night call in a night float system

Abstract Background Because of work hour regulations, many surgical residency programs have moved to a night float system. Previously, our medical students took call for 24 hours, whereas currently they also follow a night float system. This study looked at their evaluations of these 2 systems. Methods Students were anonymously surveyed to evaluate the rotation (on a 5-point scale) as well as various components including night call. Responses from each group were compared. Results There were 104 students included: 46 in the traditional 24-hour call group and 58 in the night float group. Students rated night call significantly higher in the night float system (4.62 ± .64 vs 3.52 ± 1.00, P Conclusions After switching to a night float system, students had a much more positive perception of their night call experience. We believe more clerkships should switch to a night float system.
Congestive Heart Failure More Bad News From Exercising Muscle

A hallmark of congestive heart failure (CHF) is exercise intolerance.1–5 In this context, CHF can cause exercise-limiting changes in every key step in the oxygen transport system. For example: See p 3049 A key question, then, is are these maladaptations related or are they merely a summation of physiological “bad luck” associated with poor cardiac function and the resultant physical inactivity? Over the past 20 years one revolutionary idea has been that “overactivation” of the sympathetic nervous system in CHF makes a bad situation worse and broadly contributes to a downward spiral in many elements of the oxygen transport system.6,7 In addition, during exercise, an inappropriately robust sympathetic response further limits exercise tolerance by evoking larger (and faster) than normal increases …
Distribution and Origin of Magnetite Spherules in Air, Waters, and Sediments of the Greater New York City Area and the North Atlantic Ocean

ABSTRACT Perfectly spherical sand to clay size particles composed of magnetite occur in a wide variety of environments. Within the greater New York City area such spherules are found in smoke-stack filtrate, urban-air filtrate, ditritus collected from highway surfaces, lake sediments, marsh sediments, and in beach sands. The abundance of spherules in such environments diminishes away from industrial centers. The abundance of magnetite spherules in core samples of lake and marsh sediment decreases sharply near the palynologically determined stratigraphic boundary separating sediments deposited before the area was settled and industrialized from sediments deposited afterward. Their abundance in samples of deep ocean-floor sediment also drops off sharply within the upper 10 cm of core. The spheru es become rare to absent below this depth. We conclude that the great majority of magnetic spherules presently accumulating in sediments are of industrial origin, while we recognize the existence of spherules of probable extraterrestrial origin in ancient sediments. The ease of identification and recovery of magnetite spherules from sediments facilitates their use as indicators of probable post-industrial age.
Optimizing Empiric Antibiotic Therapy in Patients with Severe β-Lactam Allergy

Antibiotic selection is challenging in patients with severe β-lactam allergy due to declining reliability of alternate antibiotics. Organisms isolated from these patients may exhibit unique resistance phenotypes. The objective of this study was to determine which alternate antibiotics or combinations provide adequate empirical therapy for patients with β-lactam allergy who develop Gram-negative infections at our institution. We further sought to determine the effects of risk factors for drug resistance on empirical adequacy. A retrospective analysis was conducted for adult patients hospitalized from September 2009 to May 2010 who had a severe β-lactam allergy and a urine, blood, or respiratory culture positive for a Gram-negative organism and who met predefined criteria for infection. Patient characteristics, culture and susceptibility data, and predefined risk factors for antibiotic resistance were collected. Adequacies of β-lactam and alternate antibiotics were compared for all infections and selected subsets. The primary outcome was adequacy of each alternate antibiotic or combination for all infections. One hundred sixteen infections (40 pneumonias, 67 urinary tract infections, and 9 bacteremias) were identified. Single alternate agents were adequate less frequently than β-lactams and combination regimens. Only in cases without risk factors for resistance did single-agent regimens demonstrate acceptable adequacy rates; each factor conferred a doubling of risk for resistance. Resistance risk factors should be considered in selecting empirical antibiotics for Gram-negative pathogens in patients unable to take β-lactams due to severe allergy.
Tungsten-carbon multilayer system studied with x-ray scattering

The tungsten-carbon multilayer system has been studied using x-ray scattering techniques as a function of multilayer period and annealing. Grazing incidence x-ray scattering shows that interatomic arrangements in the W-rich layers depend strongly on their proximity to the interface with the C-rich layers. Amorphous interface layers are stabilized by intermixing of W and C during deposition into local structures similar to those in the tungsten carbides. Further intermixing and structural relaxation in the amorphous state occurs on annealing these structures. This interatomic structural interpretation is consistent with trends in the observed x-ray optical properties. 7 refs., 4 figs.
An Improved Space-Division Multiple-Access Strategy for Rayleigh-Fading Channels

We propose a new transmission strategy for the Rayleigh-fading multiple-access channel called space-time active rotation (STAR). STAR is a simple enhancement of the traditional space-division multiple-access (SDMA) strategy that enables a successive-cancellation (SC) decoder to approach the outage probability of the underlying multiple-access channel. We derive the outage probability of a STAR system with SC decoding and propose an ordering algorithm that minimizes this outage probability. We derive an upper bound on the diversity-multiplexing tradeoff of the system. We present numerical results for a 4-user Rayleigh-fading multiple-access channel, with 2 transmit antennas per user and 8 receive antennas, which show that the STAR strategy with SC decoding falls only 1.6 dB short of the optimum outage probability. When restricted to SC decoding, STAR outperforms conventional SDMA by 8.2 dB
Operative confidence of graduating surgery residents: a training challenge in a changing environment.

Abstract Background Given the recent changes in general surgical training, this study was undertaken to assess the confidence of graduating general surgery residents in performing open operations and to determine factors that are associated with increased confidence. Methods A survey was sent to the 5th-year general surgery residents in the Northeast. Respondents were queried regarding demographics, program characteristics and asked to rate their confidence in performing open operations. We compared those who indicated confidence with those who did not. Results We received 232 responses: 74% male, 70% from university programs, and 50% from programs affiliated with a Veterans Affairs Hospital. Fifty-two percent expressed confidence in their ability to practice independently after residency. Operative confidence varied with sex, type of training program, affiliation to a Veterans Affairs Hospital, and surgical volume. Conclusions Graduating surgical residents indicated a significant lack of confidence in performing a variety of open surgical procedures. Analyzing and addressing this confidence deficit merits further study.
Network-based multicomputers: an emerging parallel architecture

Multicomputers built around a general network are now a vi­ able alternative to multicomputers based on a system-specific interconnect because of architectural improvements in two areas. First. the host-network interface overhead can be minimized by reducing copy operations and host interrupts. Second. the network can provide high bandwidth and low latency by using high-speed crossbar switches and efficient protocol implementations. While still enjoying the flexibility of general networks. the resulting network-based multicom­ puters achieve high performance for typical multicomputer applications that use system-specific interconnects. We have developed a network-based multicomputer called Nectar that supports these claims.
Physical Activity After Total Joint Arthroplasty

Total joint arthroplasty (TJA) is one of the most successful treatment options for patients with painful degenerative joint disease.18 Of the various types of TJA, total hip arthroplasty (THA) and total knee arthroplasty (TKA) have become well accepted as reliable and suitable surgical procedures to relieve pain, return lower extremity function, and improve health-related quality of life.3 There are fewer studies regarding activity after total shoulder arthroplasty (TSA).51 Pain relief has historically been the primary indication for total joint replacement; there are expected and relatively predictable gains in functional activities of daily living. Worldwide, more than 500 000 total joints are implanted yearly27 with approximately 300 000 knee replacements performed each year in the United States alone.22 Although pain relief has historically been the primary indication for TJA, more and more individuals are now seeking TJA to maintain an active lifestyle; specifically, patients are seeking surgical interventions to restore their ability to participate in various athletics.54 Many patients have embraced higher expectations for an active lifestyle, incorporating athletic activities as part of their functional goals following surgery. With the trend toward demand for higher performance, exercise, and athletic activity, clinicians have been increasingly forced to question how much athletic activity a patient can participate in after TJA and what kind of athletic activities are deemed acceptable. Defining “reasonable” levels of activity with predictable outcomes has proven to be a difficult task.
Mechanical Properties and Morphology of Polycrystalline 3C-SiC Films Deposited on Si and SiO2 by LPCVD

Poly-SiC films were deposited on Si and SiO2 substrates in a high-throughput, low pressure chemical vapor deposition (LPCVD) furnace using dichlorosilane (DCS) and acetylene precursors. The deposition temperature and pressure were fixed at 900°C and 2 Torr, respectively, while the flow rate of DCS was varied between 18 and 54 sccm. Poly-SiC deposition rates on both Si and SiO2 were nearly identical to each other and increased as a function of DCS flow rate. Consistent with both substrate materials, the following observations were made. A slope change of the deposition rate versus DCS flow rate was observed around a DCS flow rate of 35 sccm. Residual stress varied with respect to the deposition rate, with tensile stresses occurring at lower deposition rates and compressive stresses at higher deposition rates. The tensile-to-compressive stress transition corresponded to the slope change of the deposition rate versus DCS flow rate. The surface morphology consisted of pyramidal grains, as observed under an SEM. TEM analysis for poly-SiC films grown on Si substrates showed that microstructural differences exist for poly-SiC films having tensile and compressive stresses.
Black Bear, Ursus americanus , Denning Chronology and Den Site Selection in the Northeastern Cascades of Washington

I studied Black Bear denning chronology and den site selection during 1995-1998 in the northeastern Cascade Mountains of Washington. Male Black Bears entered dens between 22 October and 19 November and emerged between 4 April and 7 May. Females entered dens somewhat sooner, between 15 October and 19 November, and emerged later than males, 4 April and 22 May. These den entry and emergence dates were similar to those reported at similar lattitudes in northwestern Montana. Roads had an important influence on den site selection by Black Bears in this study area. Bears selected dens in areas with no open roads >200 ha in size, >500 m from the nearest open road, and 1500-2000 m in elevation. The combination of information on denning chronology and site characterstics should allow managers to coordinate human activities to reduce the potential for disturbance to denning Black Bears.
Tidal sedimentation from a fluvial to estuarine transition, Douglas Group, Missourian-Virgilian, Kansas

ABSTRACT The Tonganoxie Sandstone Member of the Stranger Formation (Douglas Group, Upper Pennsylvanian, Kansas) was deposited in a funnel-shaped, northeast-southwest-trending paleovalley that was incised during the uppermost Missourian sealevel lowstand and backfilled during the subsequent transgression. Quarry exposures of the Tonganoxie near Ottawa, Kansas, include 5 m of sheetlike, vertically accreted siltstones and sandy siltstones, bounded above and below by thin coals with upright plant fossils and paleosols. Strata range from submillimeter-thick, normally graded rhythmites to graded bedsets up to 12.5 cm thick with a vertical sedimentary structure sequence (VSS) consisting of the following intervals: (A) a basal massive to normally grad d interval; (B) a parallel-laminated interval; (C) a ripple-cross-laminated interval; and (D) an interval of draped lamination. The VSS-C intervals of thicker bedsets are characterized by climbing ripples that evolve from Type A (erosional-stoss) to Type B (depositional-stoss). Synsedimentary convolutions at the tops of many climbing-ripple sequences and a variety of water-escape structures indicate rapid deposition. The vertical sequence of sedimentary structures indicates each bedset was deposited by a waning current with significant suspended load. The Tonganoxie succession has many similarities to fluvial overbank/floodplain deposits: sheetlike geometry, upright plant fossils, lack of bioturbation and body fossils, dominance of silt, and a punctuated style of rapid sedimentation from suspension-laden waning currents. Missing, however, are thick clay drapes or evidence of prolonged exposure and desiccation, which generally characterize a floodplain sequence with seasonal overbanking. Physical and biogenic sedimentary structures--including tetrapod trackways, surface grazing traces, abundant raindrop impressions, wind ripples, runnel marks, runnel marks, and runoff washouts--indicate that subaerial exposure was periodic and brief, and may have followed each sedimentation event. Analysis of stratum-thickness variations through the succession suggests that tides significantly influenced sediment deposition. Strata ranging through three orders of magnitude systematically thicken and thin, recording the influence of an ebb-dominated, diurnal tidal system with a well developed semimonthly inequality. By conservative estimate of sedimentation rates based on neap-spring tidal cycles, the sequence aggraded at an average rate of approximately 3.8 m/yr. These unusually high rates appear to have prevailed for only a short time and were probably spatially restricted within the basin. A fluvial-to-estuarine transitional depositional setting is interpreted for the Tonganoxie by analogy with modern depositional settings that show similar physical and biogenic sedimentary s ructures, vertical sequences of sedimentary structures, and aggradation rates.
Physician Attitudes Regarding Breakthrough Varicella Disease and a Potential Second Dose of Varicella Vaccine

OBJECTIVE. We assessed physicians’ attitudes about the 1-dose varicella vaccination program and whether physicians think a 2-dose recommendation is needed to reduce the risk of breakthrough disease. METHODS. We conducted a national mail survey of a random sample of 550 pediatricians and 550 family physicians from April to June 2005. Physicians who provide outpatient primary care to children ≤6 years of age were eligible for analysis. RESULTS. Surveys were returned by 727 respondents, for a response rate of 69%; 610 physicians were eligible. Most respondents (94%) recommend routine 1-dose varicella vaccination, and 79% have seen breakthrough disease in the past 5 years (95% of pediatricians and 58% of family physicians). The majority (68%) agreed or strongly agreed that the current burden of breakthrough disease is acceptable. Only 38% (46% of pediatricians and 28% of family physicians) agreed or strongly agreed that a second dose of varicella vaccine is needed to address the burden of breakthrough disease, whereas 40% were neutral. However, if the Advisory Committee on Immunization Practices were to recommend a second dose of varicella vaccine, then 65% of pediatricians and 39% of family physicians would likely follow the recommendation. Most respondents (78%) would be more willing to recommend a second dose if a combination measles-mumps-rubella-varicella vaccine was available. CONCLUSIONS. Pediatricians and family physicians support the 1-dose varicella vaccination program. A new Advisory Committee on Immunization Practices recommendation for a second dose of varicella vaccine for children was issued after the survey (in June 2006). Two of 3 pediatricians and 2 of 5 family physicians stated that they would adopt a 2-dose recommendation in practice; rates of adoption may be bolstered with current availability of measles-mumps-rubella-varicella vaccine and harmonization of the varicella vaccination schedule with that of measles-mumps-rubella vaccine.
Plasma Sterilization: Opportunities and Microbial Assessment Strategies in Medical Device Manufacturing

Non-thermal gas discharge plasmas have significant potential as novel sterilization/decontamination agents in medical device manufacturing, and such agents may well be accepted by regulatory agencies. A number of aspects of plasma technology are currently under active investigation by many institutions and companies in order to obtain a thorough understanding of plasma sterilization as an alternative to conventional sterilization methods for heat sensitive medical devices. This paper focuses on the use of plasmas in microbial inactivation in medical-device manufacturing, describing some of the opportunities and microbial assessment strategies, as well as a possible surrogate for assessing microbial inactivation by plasma.
ESTIMATING THE MAGNITUDE OF ENVIRONMENTAL STOCHASTICITY IN SURVIVORSHIP DATA

Small populations are often at risk of extinction through processes that are effectively stochastic. Prediction of this extinction risk requires that the observed temporal variation in demographic rates be accurately partitioned between demographic stochasticity (variation among individuals) and environmental stochasticity (variation among years, correlated across individuals). However, studies of population viability analysis that include both forms of stochasticity parameterize the magnitude of environmental stochasticity incorrectly (they overestimate it). I describe and evaluate tests (1) to determine whether all the year-to-year variation in observed survivorship can be explained by demographic stochasticity alone, and (2) if not, to estimate the magnitude of environmental stochasticity in survival. The first issue can be resolved with a G test. I used simulated data to show that this test has an appropriate type I error rate, unless the individual survival probability is either very low or very high. Small amounts of environmental stochasticity often are not detected by the G test (type II error), but the hypothesis of demographic stochasticity alone is consistently rejected when environmental stochasticity is large. In contrast, estimating the magnitude of environmental stochasticity requires explicit hypotheses about the nature of the underlying variation, but I provide a flexible framework in which many such hypotheses can be examined. In particular, I show, using simulated data, that if the temporal variability in individual survival probabilities is distributed according to a beta distribution, then the maximum likelihood estimate of the variance of the survival probability is biased, but in a consistent and correctable way. The estimate obtained with my method is usually superior to an estimate that assumes that all of the variation in the observed survivorship is due to environmental stochasticity. I show how to include deterministic sources of variability, such as density dependence, and how to apply different assumptions about the underlying environmental stochasticity. I illustrate these tests with data from a population of Acorn Woodpeckers (Melanerpes formicivorus). With these data, I can determine that there is strong environmental stochasticity in juvenile survival, whereas variation in adult survival can be explained either by density dependence or by weak environmental stochasticity.
Sclerosteosis Nemogenetic and pathophysiologic analysis of an American kinship

We studied an American kinship with sclerosteosis, an autosomal-recessive disorder of bone remodeling and bone overgrowth of the calvaria, skull base, and tubular bones. Unlike osteopetrosis, which is attributed to abnormal immune and osteoclast function as well as bone resorption, sclcrosteosis appears to be primarily a disorder of osteoblast (bone formation) hyperactivity. Related to cranial vascular and neural foramina1 narrowing and reduced intracranial volume, affected patients with sclerosteosis demonstrate frequent seventh nerve palsy, progressive optic and cranial neuropathics, mixed hearing loss, brainstem compression, intracranial hypertension with increased elastance, and sudden, premature death. Management should involve early childhood identification of homozygotes, monitoring and aggressive treatment of intracranial hypertension, and extensive bone removal from skull, posterior fossa, and cervical spine.