cssi/SciSciGPT-SciSciNet huggingface dataset:
Physical dissipation and the method of controlled Lagrangians

We describe the effect of physical dissipation on stability of equilibria which have been stabilized, in the absence of damping, using the method of controlled Lagrangians. This method applies to a class of underactuated mechanical systems including "balance" systems such as the pendulum on a cart. Since the method involves modifying a system's kinetic energy metric through feedback, the effect of dissipation is obscured. In particular, it is not generally true that damping makes a feedback-stabilized equilibrium asymptotically stable. Damping in the unactuated directions does tend to enhance stability, however damping in the controlled directions must be "reversed" through feedback. In this paper, we suggest a choice of feedback dissipation to locally exponentially stabilize a class of controlled Lagrangian systems.
Hybrid Model Predictive Power Management of A Fuel Cell‐Battery Vehicle

This paper considers optimal power management of a fuel cell-battery hybrid vehicle (FCHV) powertrain having three distinct modal configurations (modes): electric motor propelling/battery discharging, propelling/charging, and generating/charging. Each mode has a distinct set of dynamics and constraints. Using component dynamical/algebraic models appropriate to power flow management, the paper develops a supervisory-level switched system model as an interconnection of subsystems. Given the model, the paper sets forth a hybrid model predictive control strategy based on a minimization of a performance index (PI) that trades off tracking and fuel economy in each operational mode. Specifically, the PI trades off velocity tracking error, battery state of charge variance, and electric drive and hydrogen fuel usages while penalizing frictional braking to encourage regenerative braking. The optimization is performed using an embedded system model and collocation with matlab's fmincon to compute mode switches and continuous time controls. The methodology avoids the computational complexity of alternate approaches based on, e.g., mixed integer programming. Projection methods for approximating the switched system solution from the embedded solution are empirically evaluated. To demonstrate the methodology, an example of a FCHV is simulated using three standard velocity driving profiles: a sawtooth profile with a hill climb, the EPA urban dynamic driving schedule, and the New European Driving Cycle. Also, drive cycle fuel usage is compared to that from the Equivalent Consumption Minimization Strategy.
Human genome-wide expression analysis reorients the study of inflammatory mediators and biomechanics in osteoarthritis

A major objective of this article is to examine the research implications of recently available genome-wide expression profiles of cartilage from human osteoarthritis (OA) joints. We propose that, when viewed in the light of extensive earlier work, this novel data provides a unique opportunity to reorient the design of experimental systems toward clinical relevance. Specifically, in the area of cartilage explant biology, this will require a fresh evaluation of existing paradigms, so as to optimize the choices of tissue source, cytokine/growth factor/nutrient addition, and biomechanical environment for discovery. Within this context, we firstly discuss the literature on the nature and role of potential catabolic mediators in OA pathology, including data from human OA cartilage, animal models of OA, and ex vivo studies. Secondly, due to the number and breadth of studies on IL-1β in this area, a major focus of the article is a critical analysis of the design and interpretation of cartilage studies where IL-1β has been used as a model cytokine. Thirdly, the article provides a data-driven perspective (including genome-wide analysis of clinical samples, studies on mutant mice, and clinical trials), which concludes that IL-1β should be replaced by soluble mediators such as IL-17 or TGF-β1, which are much more likely to mimic the disease in OA model systems. We also discuss the evidence that changes in early OA can be attributed to the activity of such soluble mediators, whereas late-stage disease results more from a chronic biomechanical effect on the matrix and cells of the remaining cartilage and on other local mediator-secreting cells. Lastly, an updated protocol for in vitro studies with cartilage explants and chondrocytes (including the use of specific gene expression arrays) is provided to motivate more disease-relevant studies on the interplay of cytokines, growth factors, and biomechanics on cellular behavior.
Observation of Saturation of Fidelity Decay with an Atom Interferometer

We use an atom interferometer to investigate the dynamics of matter waves in a periodically pulsed optical standing wave: an atom optics realization of the quantum kicked rotor that exhibits chaotic classical dynamics. We experimentally show that a measure of the coherence between the interferometer diffraction orders can revive after a quick initial loss, and can approach a finite asymptote as the number of kicks increases. This observation demonstrates that quantum fidelity of a classically chaotic system can survive strong perturbations over long times without decay.
X-Sigma-Rho and Market Efficiency

Menchero and Davis (2011 ) define X-Sigma-Rho as a risk metric that shows the marginal contribution to risk when a security is added to a portfolio of other securities. While insightful regarding risk, their work is incomplete because it does not consider the marginal contribution to return. This paper completes their analysis by including marginal contribution to return. In equilibrium the result is the capital market line and a measure similar to Jensen’s alpha that can be used to measure performance.
Cost-effectiveness Analysis of Antiemetic Therapy for Ambulatory Surgery

Study Objective: To compare the relative cost-effectiveness ratios of (1) therapy with ondansetron, droperidol, and metoclopramide in the prevention of postoperative nausea and vomiting (PONV), and (2) prophylactic versus rescue therapy of PONV with these agents. Design: Cost-effectiveness analysis based on the estimated costs of 12 mutually exclusive outcomes identified by decision analysis. Setting: Computer model of outcome established using data extracted from published studies and a survey of current practice in two university-affiliated hospitals. Patients: Patients undergoing operations associated with a high risk of PONV. Interventions: The cost-effectiveness of prophylactic antiemetic therapy was compared among three drugs and also compared with limiting treatment to established PONV. Measurements and Main Results: Direct costs included drug acquisition, drug delivery, equipment used in managing vomiting, and additional nursing time costs. Indirect costs included drugs and materials used to treat persistent nausea and/or vomiting and the side effects of prophylactic drugs, increased time spent in the postanesthesia care unit, unanticipated hospitalization, and lost earnings due to hospitalization. Separate models were created for patients with both nausea and vomiting and with isolated nausea. The total incremental costs associated with the prophylactic use of ondansetron, metoclopramide, and droperidol were $37.74, $28.43, and $18.17 per patient, respectively. The costs per emesis-free patient with the prophylactic use of ondansetron, metoclopramide, and droperidol, were $55.91, $71.08, and $30.15, respectively, and per nausea-free patient $68.93, $82.74, and $33.52, respectively. Prophylactic antiemetic therapy was cost-effective for operations with a high frequency of emesis, whereas treatment of established symptoms was more cost-effective when the frequency was lower. For ondansetron, prophylactic use was cost-effective only when the frequency of emesis exceeded 33%, whereas prophylactic droperidol was cost-effective even if the frequency was 10%. Conclusions: When drug costs, efficacy, and adverse events were all considered, prophylactic droperidol was more cost-effective than ondansetron, and both drugs were more cost-effective than metoclopramide. However, the expected frequency of PONV, as well as local drug acquisition costs, can significantly influence whether a particular antiemetic is cost-effective when given prophylactically or only as therapy for established PONV.
Insights into the mechanism of N2O reduction by reductively activated N2O reductase from kinetics and spectroscopic studies of pH effects.

Nitrous oxide reductase (N2OR) from Achromobacter cycloclastes (Ac) can be reductively activated with reduced methyl viologen over a broad range of pH. Activated Ac N2OR displays a complex activity profile as a function of the pH at which catalytic turnover is measured. Spectroscopic and steady-state kinetics data suggest that [H+] has multiple effects on both the activation and the catalytic reactions. These experimental results are in good agreement with previous theoretical studies, which suggested that the transition state is stabilized by H-bonding interactions between the active site and an N2O-derived intermediate bound to the catalytic CuZ cluster (J. Am. Chem. Soc. 2006, 128, 278−290).
Isotopic fractionation of oxygen and nitrogen in coastal marine sediments

Abstract The bulk and isotopic exchanges of O2, N2, NO3, and NH4+ between sediments and the overlying water (benthic flux) were measured at three shallow locations in Puget Sound using a benthic tripod. Oxygen consumption by the sediments averaged 4.4 mmol m−2 d−1, while N2 gas fluxes averaged 1.1 mmol M−2 d−1. The nitrogen gas flux out of the sediments was always greater than the corresponding NO3-flux into the sediments, indicating a large nitrification contribution to the N2 flux. Isotopic changes in overlying water δ18O of O2 were small, with an average apparent sediment respiration fractionation-factor, e, of 3. This fractionation-factor is much smaller than that measured in either the open ocean or in the laboratory. The low degree of fractionation is hypothesized to occur because of the interaction of diffusive layers around reactive microsites within these sediments. There was no apparent isotopic fractionation of downward-diffusing NO3− (e = 0), while the ammonium that diffused out of the sediments averaged 4.5%o heavier than both source organic matter within the sediments and overlying water NO3. The large discrepancy in isotopic composition between the source organic material and NH4+ can be attributed to significant isotopic fractionation of ammonium during nitrification in the oxic zone. Finally, the δ15N of N2 did not change significantly over the course of the incubations, in agreement with the nitrogen isotopic budget for these sediments.
ISOTROPIC CORRELATION FUNCTIONS ON d-DIMENSIONAL BALLS

A popular procedure in spatial data analysis is to fit a line segment of the form c(x) = 1 - a llx II, Ixll < 1, to observed correlations at (appropriately scaled) spatial lag x in d-dimensional space. We show that such an approach is permissible if and only if
DISCREPANCIES BETWEEN MEASURED CHANGES OF RADIOBIOLOGICAL HYPOXIC FRACTION AND OXYGEN TENSION MONITORING USING TWO ASSAY SYSTEMS

Abstract Purpose: This study was conducted to assess the ability of computerized pO 2 histography to measure changes in tumor oxygenation produced by low oxygen breathing. Methods and Materials: Female syngeneic C3H/Km mice bearing SCC VII/St carcinomas were used in these experiments. Changes in tumor oxygenation produced by the mice breathing 10% oxygen were assessed with computerized pO2 histography, 3 H-misonidazole binding, and the paired survival curve assay of radiosensitivity. Results: The hypoxic cell fraction of the tumors in mice breathing 10% oxygen was 3.1 times higher than that of tumors in mice breathing normal air determined by an in vivo-in vitro clonogenic assay. Binding of radiolabeled misonidazole to the tumors in mice breathing 10% oxygen was also significantly higher than that to tumors in mice breathing normal air ( p 2 value for the tumor. The number of pO 2 readings lower than 5 mmHg in the tumor was not affected by the 10% oxygen breathing. Conclusion: These findings indicate that increases in radiobiological hypoxic fraction produced by lower blood oxygen levels may not correlate well with the results of polarographic measurements of tumor pO 2 levels.
FETAL UMBILICAL CORD BLOOD ERYTHROPOIETIN, INTERLEUKIN-6, PH, PO2, PCO2, AND BASE EXCESS LEVELS IN HISTOLOGIC AND/OR CLINICAL CHORIOAMNIONITIS: IS THE RESPONSE ONLY INFLAMMATORY?

Objective: To determine the correlation of histological chorioamnionitis (CA) with and without clinical CA with umbilical cord blood gases, erythropoietin (EPO), and interleukin-6 (IL-6) levels. Methods: Umbilical artery blood gas analysis (pH, pO2, pC02, BE) and umbilical vein EPO and IL-6 levels were measured in 202 infants from normal, histological, and no clinical CA and histological plus clinical CA pregancies. Results: Umbilical artery blood gas analyses were not different between normal controls and histological and clinical CA groups. Blanc Stage 1 histological CA had no abnormal EPO or IL-6 umbilical blood results. EPO in umbilical venous blood was elevated only in those infants with both histological and clinical CA. Umbilical vein IL-6 levels were elevated in all advanced microscopic and clinical CA. High and low EPO groups also have corresponding high and low IL-6 levels suggesting a common stimulus for these substances. Conclusions: Blanc stage I histological CA is probably clinically insigni...
Lattice strain partitioning in a two-phase alloy and its redistribution upon yielding

Load sharing in two-phase alloys is investigated by means of finite element simulations of polycrystalline aggregates subjected to uni-axial compression. Attention is focused on the redistribution of stress as the overall load level increases and the material progresses from a purely elastic state to eventual yielding of both phases. Virtual specimens having two phases, one of iron and the other of copper, were created and subjected to compression. The lattice (elastic) strains, which are directly proportional to the stress, were examined over the course of the compression test for a system having equal volume fractions of each phase. Comparisons were made first with measurements by neutron diffraction to confirm that the simulated strains followed the observed behavior. The computed lattice strain tensors then were examined in terms of the changes in their principal directions as the overall load increased. The redirection of the stress signals a change in the relative stiffnesses of the phases, from which follows a repartitioning of stress between the phases.
Heterogeneity in Spending Change at Retirement

The simple one-good model of life-cycle consumption requires that consumption be continuous over retirement; yet prior research based on partial measures of consumption or on synthetic panels indicates that spending drops at retirement, a result that has been called the retirement-consumption puzzle. Using panel data on total spending, nondurable spending and food spending, we find that spending declines at small rates at retirement, rates that could be explained by mechanisms such as the cessation of work-related expenses, unexpected retirement due to a health shock or by the substitution of time for spending. We find substantial heterogeneity in spending change at retirement: in the upper half of the wealth distribution spending increased. In the low-wealth population where spending did decline at higher rates, the main explanation for the decline appears to be early retirement due to poor health, possibly augmented by a short planning horizon by a minority of the population.
In peace and freedom: my journey in Selma

For years, scholars and activists, politicians and law enforcement have all struggled to understand what allows certain people to respond to an outright injustice with nonviolent direct action. Mos...
Uptake, distribution, and fate of 203Hg-ethylmercuric chloride in the guppy and the coontail.

Abstract The guppy ( Lebistes resticulatus ) and coontail ( Ceratophyllum demersum ) were exposed to water containing 203 Hg-labeled ethylmercuric chloride (EMC). The EMC uptake was related to the time of exposure and the concentration of EMC. Highest concentration of 203 Hg was found in the internal organs of the guppy and the body has the least concentration. The biological half-life of 203 Hg from EMC was approximately between 20 and 23 days. Both organisms are capable of converting the absorbed EMC to inorganic mercury with the coontail having a slightly higher rate (34%) of conversion as compared to the average of 29% for the guppy during a seven-day period. Both organisms accumulated slightly more MMC than EMC from a solution containing the same concentration of EMC or MMC. There was very little conversion of MMC to inorganic mercury by the guppy, indicating the stability of MMC in this organism. The absorbed MMC molecule was also more stable than the EMC in the coontail.
Elastic scattering of 0.1-1-MeV photons

Theoretical values of Rayleigh scattering amplitudes for the $K$ shell and for higher atomic shells are calculated from the second-order $S$ matrix of quantum electrodynamics. The calculations are combined with nuclear Thomson scattering to predict elastic scattering differential cross sections for photon energies between 100 keV and 1 MeV, and for elements with $Z$ ranging from 30 to 82. The resulting cross sections are compared with recent high-precision measurements.
Mechanisms for elongation in the biosynthesis of fatty acid components of epi-cuticular waxes

It is known that branched-chain amino acids can serve as precursors to iso- and anteiso-branched components of epi-cuticular waxes. Keto acid deamination products of Val, Leu and Ile are thought to serve as primers which are elongated by fatty acid synthase. However, the origin of elongation carbons has not been studied directly. Nor has the mechanism for formation of odd-carbon-length, straight- or branched-chain, cuticular ester fatty acids or free odd-carbon-length, straight fatty acid components of waxes been characterized. It is not known that α-oxidation of even-length precursors or elongation of odd-length primers is involved in these cases. Here, we present evidence which substantiates the expectation that elongation of branched as well as straight-chain precursors to wax ester acids occurs by fatty acid synthase catalyzed by addition of two carbon units via acetate. Also, we present evidence which indicates that odd-carbon-length acids can result from elongation of odd-carbon-length primers (at least branched), rather than even-length acids shortened by α-oxidation.
Synthesis of Gal-β(1→4)-6-O-SO3Na-GlcNAc-β-(1→6)-Man-α-OR as a part of gp 120

Abstract A stereoselective synthesis of Gal-β-(1→4)-6-O-SO 3 Na-GlcNac-β-(1→6)-Man-α-OR (as a part of gp 120) containing an anomeric p-nitrophenyl group was accomplished through the use of ethyl 3,4,6-tri-O-chloroacetyl-2-deoxy-2-phthalimido-1-thio-β-D-glucopyranoside.
The Barrier to Internal Rotation in Ethane: A qualitative, intuitively useful explanation emerges from a comparison of different theoretical approaches.

The internal rotation barrier in ethane appears susceptible to "explanation" at a qualitative, intuitively useful, reasonably correct level. At this level, localized and delocalized MO9s each produce a description. For a rigid rotation, the delocalized description is basically the "orbital control" type familiar from Woodward-Hoffmann rules (30), Walsh9s rules (31), and the formation of diatomic molecules (32). This description indicates that long-range eclipsed H---H antibonding is responsible for the barrier. The equivalent localized-bond description invokes destructive interference or repulsion between eclipsed C-H bonds. The extension of this kind of description to other molecules requires care. Subsequent to rigid rotation, the relaxation of ethane into its optimum eclipsed geometry produces almost no energy change but produces an unknown degree of energy "redistribution." I have emphasized that the theoretical distinction between "orbital control" and "steric interaction" is not precise and that a clarification in terminology may be desirable in this connection. The discussion of barriers given here applies only to a limited class of molecules, exemplified by ethane. No doubt, additional factors enter into a proper description of barriers in molecules having lower symmetry or more polar bonds, or both (33). Finally, I should point out that approaches other than those in categories 1 to 3 have been made in efforts to rationalize or predict barriers to internal rotation (34). The Hellmann-Feynman theorem has been applied to find the torque on ethane at conformations between staggered and eclipsed (35). The integral Hellmann-Feynman theorem has served as a basis for discussing barriers in terms of transition densities (36) and has led to an electrostatic model for barriers which has given some remarkably successful barrier predictions (37). These approaches are mathematically valid, and it is perfectly legitimate to try to extract physical explanations from them also. Thus, several valid explanations for the barrier to internal rotation in ethane are possible. However, I feel that the explanations proposed above in terms of delocalized or localized orbitals are preferable at present inasmuch as they are couched in terms and concepts currently in the mainstream of chemical thinking.
On closeness of the sum of n subspaces of a Hilbert space

We give necessary and sufficient conditions for the sum of subspaces H 1,…, H n , n ≥ 2, of a Hilbert space H to be a subspace and present various properties of the n-tuples of subspaces with closed sum.
Significance of isolated neovascular tufts ("popcorn") in retinopathy of prematurity.

Abstract Background: The significance of isolated neovascular tufts ("popcorn") occurring in association with stage 2 retinopathy of prematurity (ROP) has not been studied. Methods: we retrospectively reviewed the clinical courses and outcomes of all patients with zone II, stage 2 ROP with popcorn examined over the past 3 years at one institution. Eyes with zone I disease, plus disease, or stage 3 at the initial appearance of popcorn were excluded. The study group was compared with a control group of patients of similar birth weight and gestational age with zone II, stage 2 ROP without popcorn. Results: Popcorn first appeared at a mean age of 36.4 (±2.2) weeks after conception in 26 patients. Of these, 17 patients (65%) progressed to stage 3, 10 (38%) had plus disease, 6 (23%) reached threshold, and 9 (35%) required laser treatment. Of 19 control patients, 4 (21%) progressed to stage 3, 1 (5%) had plus disease, 1 (5%) reached threshold, and 1 (5%) required laser treatment. The popcorn group had a significantly higher incidence of progression to stage 3 ( p p p Conclusions: The presence of popcorn significantly increases the risk that an eye with zone II, stage 2 ROP will progress to stage 3, develop plus disease, and require laser treatment. Patients with popcorn and coexistent mild vascular dilation or tortuosity insufficient for plus disease are at particularly high risk for disease progression.
Maternal Biomarkers of Endothelial Dysfunction and Preterm Delivery

Background Endothelial dysfunction is key to the development of atherosclerosis. Preterm delivery foreshadows later maternal cardiovascular disease (CVD), but it is not known if endothelial dysfunction also occurs. We prospectively measured circulating biomarkers of endothelial dysfunction in pregnant women with preterm or term delivery. Methods We conducted a case-control study nested within a large prospective epidemiological study of young, generally healthy pregnant women. Women who delivered preterm (<37 completed weeks gestation, n = 240) and controls who delivered at term (n = 439) were included. Pregnancies complicated by preeclampsia were analyzed separately. Circulating endothelial dysfunction biomarkers included soluble intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1) and soluble E-selectin (sE-selectin). Results Elevated levels of sICAM-1 and sVCAM-1 were positively associated with preterm delivery independent of usual risk factors. At entry (∼16 wks), the adjusted odds ratio (AOR) was 1.73 (95% confidence interval (CI) 1.09–2.74) for the highest quartile of sICAM-1 versus the lowest quartile and for sVCAM-1 the AOR was 2.17 (95% CI 1.36–3.46). When analysis was limited to cases with a spontaneous preterm delivery, the results were unchanged. Similar results were obtained for the 3rd trimester (∼30 wks). Elevated sE-selectin was increased only in preterm delivery complicated by preeclampsia; risk was increased at entry (AOR 2.32, 95% CI 1.22–4.40) and in the 3rd trimester (AOR 3.37, 95% CI 1.78–6.39). Conclusions Impaired endothelial function as indicated by increased levels of soluble molecules commonly secreted by endothelial cells is a pathogenic precursor to CVD that is also present in women with preterm delivery. Our findings underscore the need for follow-up studies to determine if improving endothelial function prevents later CVD risk in women.
Active Transcriptional Repression by the Rb–E2F Complex Mediates G1 Arrest Triggered by p16INK4a, TGFβ, and Contact Inhibition

Rb inhibits progression from G1 to S phase of the cell cycle. It associates with a number of cellular proteins; however, the nature of these interactions and their relative significance in cell cycle regulation are still unclear. We present evidence that Rb must normally interact with the E2F family of transcription factors to arrest cells in G1, and that this arrest results from active transcriptional repression by the Rb-E2F complex, not from inactivation of E2F. Thus, a major role of E2F in cell cycle regulation is assembly of this repressor complex. We demonstrate that active repression by Rb-E2F mediates the G1 arrest triggered by TGFbeta, p16INK4a, and contact inhibition.
How Essential Is the Intensive Care Unit After Carotid Endarterectomy

This study was designed to determine whether a short recovery room stay could safely and accurately predict which patients required the Intensive Care Unit (ICU) after carotid endarterectomy (CEA)....
The prediction of recovery using a multivariate model in 1471 depressed inpatients.

Stepwise multiple logistic regression was used in an attempt to develop a statistical model which would predict “recovery” in a group of 1471 depressives admitted to a tertiary care hospital. Six variables identified by this approach included: Electroconvulsive therapy, personality disorder, chronicity, anxiety disorder, organic mental disorder, and dysthymia. The meaning and significance of the findings are discussed.
Molecular beam epitaxial HgCdTe material characteristics and device performance: reproducibility status

Extensive material, device, and focal plane array (FPA) reproducibility data are presented to demonstrate significant advances made in the molecular beam epitaxial (MBE) HgCdTe technology. Excellent control of the composition, growth rate, layer thickness, doping concentration, dislocation density, and transport characteristics has been demonstrated. A change in the bandgap is readily achieved by adjusting the beam fluxes, demonstrating the flexibility of MBE in responding to the needs of infrared detection applications in various spectral bands. High performance of photodiodes fabricated on MBE HgCdTe layers reflects on the overall quality of the grown material. The photodiodes were planar p-on-n junctions fabricated by As ion-implantation into indium doped, n-type, in situ grown double layer heterostructures. At 77K, diodes fabricated on MBE Hg1−xCdxTe with x ≈ 0.30 (λco ≈ 5.6 μm), x ≈ 0.26 (λco ≈ 7 μm), x ≈ 0.23 (λco ≈ 10 μm) show R0A products in excess of 1 x 106 ohm-cm2, 7 x 105 ohm-cm2, and 3 x 102 ohm-cm2, respectively. These devices also show high quantum efficiency. As a means to assess the uniformity of the MBE HgCdTe material, two-dimensional 64 x 64 and 128 x 128 mosaic detector arrays were hybridized to Si multiplexers. These focal plane arrays show an operability as high as 97% at 77K for the x ≈ 0.23 spectral band and 93% at 77K for the x ≈ 0.26 spectral band. The operability is limited partly by the density of void-type defects that are present in the MBE grown layers and are easily identified under an optical microscope.
LACK OF PREDICTIVE VALUE OF THE APACHE II SCORE IN HYPOALBUMINEMIC PATIENTS

The APACHE II score predicts mortality in severely ill patients. This score does not account for the serum albumin level. Ninety-three patients (28 with serum albumin levels <2.5 g/dL [group I] and 65 with serum albumin levels ≥2.5 [group II]) were retrospectively reviewed. Patients were comparable in age, APACHE II score, and compliance with required protein needs. Patients with severe hypoalbuminemia had nearly double the death rate of patients with mildly low or normal albumin concentrations (54% compared with 29% ). The death rate in the severely hypoalbuminemic patients was 5.1-fold higher than would be predicted by their APACHE II score. The death rate in those patients with mildly low or normal albumin levels had only a 1.9-fold higher rate than would be predicted by their APACHE II score. It is concluded that severe hypoalbuminemia increases the risk of death significantly higher than would be predicted by the APACHE II score. APACHE II score is not as accurate in a severely hypoalbuminemic popula...
Computational efficiency and approximate inertial manifolds for a Bénard convection system

A computational comparison between classical Galerkin and approximate inertial manifold (AIM) methods is performed for the case of two-dimensional natural convection in a saturated porous material. For prediction of Hopf and torus bifurcations far from convection onset, the improvements of the AIM method over the classical one are small or negligible. Two reasons are given for the lack of distinct improvement. First, the small boundary layer length scale is the source of the instabilities, so it cannot be modeled as a “slave” to the larger scales, as the AIM attempts to do. Second, estimates based on the Gevrey class regularity of solutions to the governing equations show that the classical and AIM methods may be virtually equivalent. It is argued that these two reasons are physical and mathematical reflections of one another.
Laboratory Study of Air Sparging: Air Flow Visualization

Laboratory flow visualization experiments, using glass beads as the porous medium, were conducted to study air sparging, an innovative technology for subsurface contaminant remediation. The purpose of these experiments was to observe how air flows through saturated porous media and to obtain a basic understanding of air plume formation and medium heterogeneity effects. The experiments indicate that air flow occurring in discrete, stable channels is the most probable flow behavior in medium to fine grained water saturated porous media and that medium heterogeneity plays an important role in the development of air channels. Several simulated scales of heterogeneities, from pore to field, have been studied. The results suggest that air channel formation is sensitive to the various scales of heterogeneities. Site-specific hydrogeologic settings have to be carefully reviewed before air sparging is applied to remediate sites contaminated by volatile organic compounds.
Assessment of Alternate Thermal Protection Systems for the Space Shuttle Orbiter

Candidate concepts are identified. The impact on the Shuttle Orbiter performance life cycle cost, and risk was assessed and technology advances required to bring the selected TPS to operational readiness are defined. The best system is shown to be a hybrid blend of metallic and carbon-carbon TPS concepts. These alternate concepts offer significant improvements in reusability and are mass competitive with the current ceramic tile reusable surface insulation. Programmatic analysis indicates approximately five years are required to bring the concepts to operational readiness.
Magnetic Anisotropy in Antiferromagnetic Corundum-Type Sesquioxides

Evaluations of the magnetic dipolar anisotropy ${K}_{\mathrm{MD}}$ are made for the antiferromagnetic Cr, Fe, Ti, and V sesquioxides isomorphous to $\ensuremath{\alpha}\ensuremath{-}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}$. In the first two systems the fine structure anisotropy ${K}_{\mathrm{FS}}$ is found by substracting ${K}_{\mathrm{MD}}$ from the total anisotropy $K$ obtained from antiferromagnetic-resonance (AFMR) data. In Shull magnetic configuration type (c), of which ${\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}$ is the prototype, ${K}_{\mathrm{MD}}$ was found to be very sensitive to lattice geometry. Owing to the use of inappropriate crystal data, a previous ${\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}$ ${K}_{\mathrm{MD}}$ calculation is shown to be in serious error. The ${\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}$ AFMR results are reinterpreted accordingly. An analysis is also made for $\ensuremath{\alpha}\ensuremath{-}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ [Shull case (a)] for which some AFMR data have recently become available. The $\ensuremath{\alpha}\ensuremath{-}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ spin flip near 250 \ifmmode^\circ\else\textdegree\fi{}K is predictable on a thermodynamic basis. The ${K}_{\mathrm{FS}}$ results in the Cr and Fe cases show little correlation with the corresponding quantities derived from EPR in diluted magnetic systems. The results of variation of lattice parameters are given for possible application to temperature and stress experiments and to diluted crystals. Since the antiferromagnetic properties of the Ti and V oxides currently are not clear, we present the appropriate ${K}_{\mathrm{MD}}$ calculations for each of the three possible spin configurations.
The periaqueductal gray projections to the rat spinal trigeminal, raphe magnus, gigantocellular pars alpha and paragigantocellular nuclei arise from separate neurons

Possible collateral branches of periaqueductal gray axons which distribute to the nucleus raphe magnus, nucleus reticularis paragigantocellularis, nucleus reticularis gigantocellularis pars alpha and the spinal trigeminal nucleus were analyzed with the double fluorescent retrograde tracer technique. With the exception of a small number of double-labeled neurons observed in the periaqueductal gray following injections of fluorescent dyes into the nuclei reticularis paragigantocellularis and gigantocellularis pars alpha, no double-labeled cells were found in this midbrain region following injections of tracers into various combinations of the above 4 nuclear groups. The results of this investigation indicate that these 4 brainstem nuclei are innervated predominantly by separate neuronal populations within the periaqueductal gray.
Agency Utilization of Free Internet Web Sites

ABSTRACT A social services department in the United Kingdom established a web portal and provided resources to enable agencies to publish their own pages on the Internet. Numerous web features were available, but few agencies utilized them. The portal is described, features identified, and several explanatory factors that may explain variance in uptake are considered.
Studies on the binding of turnip yellow mosaic virus RNA to Escherichia coli ribosomes

Abstract A technique for the rapid and quantitative assay of messenger RNA binding to ribosomes is described and used to study the association of turnip yellow mosaic virus RNA with Escherichia coli ribosomes. A limited number of sites in this RNA can associate specifically with 30 s ribosomal subunits. The binding (Keq ≈ 108 l./mole; ΔH ∘ = − 12 kcal./mole) is stabilized by magnesium ions, destabilized by potassium ions (at high magnesium ion concentrations) and independent of pH in the range 6.8 to 8.2. Neutralization of negative charges by either magnesium or potassium ions is required for binding. The rate of association (k ≈ 108 l./mole sec; ΔHǂ = 11 kcal./mole ) is first-order with respect to ribosomes and RNA. These results are discussed in relation to a model of messenger RNA-ribosome interaction.
A comparison of MoSi2 matrix composites with other silicon-base composite systems

Abstract Molybdenum disilicide offers the potential of enhancing the mechanical properties of silicon-base composite structural materials. This material can be alloyed with other ceramics, e.g. Si 3 N 4 , to increase the cracking strength, toughness, and oxidation resistance. Matrix toughness is shown to have a significant influence on increasing the matrix cracking stress and is one of the few material variables that can be controlled. The uniaxial stress-strain behavior of MoSi 2 –Si 3 N 4 matrix composites reinforced with SCS-6 fibers demonstrates a high load carrying capacity at high strains. The overall toughness can also be significantly enhanced, particularly at high temperatures. These results suggest that the alloying capabilities of MoSi 2 matrix systems will provide the flexibility needed to achieve further improvements in material performance for silicon-base composites.
Distribution patterns of dissolved organic matter fractions in natural waters from eastern Canada

Abstract Dissolved organic matter (DOM) in natural waters from eastern Canada, when fractionated into humic acid (HA) and six fulvic sub-fractions—hydrophobic acid, base and neutral (HPOA, HPOB, and HPON), and hydrophilic acid, base, and neutral (HPIA, HPIB, and HPIN)—shows a high degree of variability in the distribution of fractions. On average the fractions are ranked by concentration (mgC/1): HPOA > HPON > HA > HPIN > HPIA > HPIB > HPOB, and 59.7% of the dissolved organic carbon (DOC) is contained in fractions defined as acidic (HA + HPOA + HPIA). Localized conditions are more important in determining the character of DOM than are seasonal fluctuations. Fractionation of DOM yields information on its biogeochemistry which is not obtainable from DOC measurements alone, but further characterization is required to fully understand the influence of DOM character on natural acidity and metal complexation.
Ionic equilibria in mixed solvents

Abstract An equation correlating the thermodynamic ionization constants of monoprotic (carboxylic) organic acids in a mixed solvent and a reference solvent (water) is derived employing a curve-fitting program. The equation covers the range of bulk dielectric constant represented by that of pure water and that of very concentrated organic component. An equation for interconversion of the ionization constants between two solvents is also described. The form of the equations is similar to that of Born's equation. Interionic distances between hydrated proton and the hydrated anions were calculated for a large number of acids using the constants of the equations, and these distances are of the right order of magnitude. The bulk dielectric constant of the organic component of the solvent may be computed utilizing the constants of the equation; the computed values of bulk dielectric constants of solvents were less than 7% off from the experimental values.
The Ceramic Technology Project: Ten Years of Progress

The Ceramic Technology Project was initiated in 1983 for the purpose of developing highly reliable structural ceramics for applications in advanced heat engines, such as the automotive gas turbines and advanced heavy duty diesel engines. The reliability problem was determined to be a result of uncontrolled populations of processing flaws in the brittle, flaw-sensitive materials, along with microstructural features, such as grain boundary phases, that contribute to time dependent strength reduction in service at high temperatures. The approach taken to develop high reliability ceramics included the development of tougher materials with greater tolerance to microstructural flaws, the development of advanced processing technology to minimize the size and number of flaws, and the development of mechanical testing methodology and the characterization of time dependent mechanical behavior, leading to a life prediction methodology for structural ceramics.
Turn a Nintendo Wiimote into a Handheld Computer Mouse

This article describes how to turn a Wiimote into a wireless mouse to operate a computer. It can be widely used in classrooms and conference rooms for presentation and interactive discussion. Most of all, it allows multiple users to use multiple Wiimotes to operate the same computer. Currently we are exploring the approaches to use Wiimotes to construct a motion tracking system that can be used in a virtual reality environment.
A generalization result regarding the small and large scale behavior of infinitely divisible processes

Abstract General conditions for normalized, time-scaled stochastic integrals of independently scattered Levy random measures to converge to a limit are described. The idea is to provide general conditions to bypass the use of characteristic functions, which can sometimes have tedious calculations, to simplify and shorten the proofs of convergence of infinitely divisible processes, which have previously been done on a case by case basis. It is of particular interest to study both small and large scale asymptotics, since there are many applications, such as modeling internet traffic. The purpose of this paper is to generalize previous results to the greater class of all stochastically continuous (or, more generally, separable in probability) infinitely divisible processes with no Gaussian part and to expand the results to the multi-dimensional case.
Purification and structural characterization of polybrominated biphenyl congeners

Only three congeners of the environmental contaminants polybrominated biphenyls (PBBs) have previously been identified. PBBs were fractionated and subjected to instrumental analysis. In order of their gas chromatographic elution, the additional congeners identified were 2,2′,4,5,5′-penta-, 2,3′,4,4′,5-penta-, 2,2′,3,4,4′,5′-hexa-, 2,3′,4,4′,5,5′-hexa-, 2,2′,3,3′,4,4′,5,5′-octa-, and 2,2′,3,3′,4,4′,5,5′,6-nonabromobiphenyl. Increasing ortho bromination caused a characteristic upfield shift of the 1H-NMR signals from the remaining ortho protons.
Changes in the abundance of the seagrassesZostera marina L. (eelgrass) andRuppia maritima L. (widgeongrass) in San Diego, California, following and El Niño Event

Changes in environmental conditions can be accompanied by shifts in the distribution and abundances of organisms. When physical factors become unsuitable for growth ofZostera marina (eelgrass), which is a dominant seagrass species in North America, other more ruderal seagrass species, includingRuppia maritima (widgeongrass), often increase in abundance or replace the dominant species. We report the proliferation of widgeongrass into eelgrass beds in Mission Bay and San Diego Bay in San Diego, California, during the 1997 to 1998 El Nino Southern Oscillation (ENSO). Widgeongrass persisted in these eelgrass beds at least one year after a return to non-ENSO conditions and an increase in eelgrass density. We suggest that a warming of the water in two bays in San Diego by 1.5–2.5°C could result, in a permanent shift in the local seagrass vegetation from eelgrass to widgeongrass. This shift, could, have substantial ecosystem-level ramifications.
The Voices of Single Parent Mothers Who are Homeless: Implications for Early Childhood Professionals

Single parent mothers who are homeless have distinct ideas about how to resolve their situations. This study explored the voices of single parent mothers who are homeless and attempted to articulate their major concerns and ideas as well as offering ideas to early childhood professionals related to these insights. The voices of these mothers are highlighted in this study and related to the findings of the research literature on homeless mothers. Finally, the implications for early childhood professionals are explicated and briefly discussed.
Λb and heavy states at the Tevatron

We present the recent results of the CDF and DO collaborations on the Λ b baryon and other heavy states from the analysis of data collected in the Run II of the Tevatron Collider during the period of 2002 -2004.
L-shell x-ray fluorescence measurements of lead in bone: system development.

This paper reports on the development of an L-shell x-ray fluorescence (XRF) bone lead measurement system. A secondary target gave greater lead x-ray peak signal-to-background ratios than partially plane polarized XRF. Filtration did not improve the lead x-ray peak signal-to-background ratio: the gains in spectrum quality were outweighed by the losses caused by attenuation. There was a substantial matrix effect: the signal from a calcium-rich matrix was far lower than that from a calcium-free matrix. The effect of attenuation was, as expected, profound for the lead L x-rays: detection limits ranged from 18 to 217 μg Pb/g plaster with attenuation equivalent to 0–2.1 mm of skin or 0–3.7 mm of adipose tissue for the Pb Lα x-ray group (10.5 keV), and from 16 to 184 μg Pb/g plaster with attenuation equivalent to 0–1.3 mm of skin or 0–2.3 mm of adipose tissue for the Pb Lβ x-ray group (12.6 keV).
The use of action variables in determining recommendation domains: Grouping senegalese farmers for research and extension

Abstract The Ziguinchor Region of Senegal is considered the breadbasket of the nation, yet agricultural production has consistently failed to meet expectations and needs. The reason given for the deficit in production is the failure of researchers and development agents in providing appropriate technologies to targeted farmers with similar priorities, potentials and constraints. This group of farmers form recommendation domains (RDs). In this paper, cluster analysis was used to classify farm family units into RDs using endogenous and exogenous variables to the farming system. Canonical-discriminant analysis was used to identify the factors influencing homogeneous groups of farmers in attaining food self-sufficiency. This process of isolating RDs is considered appropriate in providing researchers with an effective tool in determining the factors which affect farmers' productivity, and hence articulating research and extension efforts to meet farmers' needs. Information gathered through this method can then be more readily translated into a policy framework.
Model of energetic electron transport in magnetron discharges

A particle model of energetic electron transport in sputtering magnetron discharges is presented. The model assumes time‐independent magnetic and electric fields and supposes that scattering by neutral atoms is the dominant transport mechanism. Without scattering, we find that some orbits are confined indefinitely. Using the differential cross sections for elastic, excitation, and ionization collisions in argon, we perform a Monte Carlo simulation of the electrons emitted by ion bombardment of a planar magnetron cathode to predict the spatial distribution of ionization. We find good agreement with experimental measurements of the radial profile of ion flux to the cathode and of the axial profile of optical emission.
The role of nitrazepam in intractable seizures in childhood

Thirty-one children (5 months to 19 years) with medically intractable childhood epilepsy had nitrazepam added to their antiepileptic drug (AED) regimen. All patients had previously received phenobarbital, phenytoin, carbamazepine, valproate, and at least one benzodiazepine. Most patients (22) had multiple seizure types, including atonic, tonic, myoclonic, complex partial, and generalized tonic—clonic, whereas nine had ony one seizure type. Initially, 24 patients (77.4%) had a greater than 25% decrease in seizure frequency, whereas 19 (61%) had an improvement of greater than 50%. Tolerance occurred in 12 of 23 (43.4%) responders, at a mean period of 7 weeks. Eight of these 12 improved after further nitrazepam dosage increases, maintaining a greater than 25% decrease in seizure frequency as compared to baseline. On follow-up (mean, 5.4 months), 65% of our 31 patients maintained a seizure reduction greater than 25%, and in 54% this reduction was greater than 50% ( p ⩽ 0.001, McNemar's test). We conclude that nitrazepam is a useful adjunctive AED in intractable childhood epilepsy despite the occurrence of tolerance in over one-third of the patients. Furthermore, previous failure of benzodiazepine therapy does not preclude a positive response to nitrazepam.