cssi/SciSciGPT-SciSciNet huggingface dataset:
Modeling of the nonlinear perpendicular recording readback signal

Perpendicular recording has been proposed as a better recording technology than the traditional longitudinal recording for high-density recording systems. The change in the recording format from longitudinal to perpendicular recording brings about new challenges in head, media, and channel designs. One of these challenges is the increasing amount of read and write nonlinearities. In addition, the nature of these nonlinearities may not be the same as in longitudinal recording. We developed a model for characterizing and modeling nonlinearities, regardless of their nature or severity, based on finite memory Volterra series. It was determined that a Volterra Model does not adequately model the perpendicular recording signal due to the fact that perpendicular recording suffers from very long inter-symbol interference (ISI). The long ISI is due to the presence of droop effect and high pass filter effects of the preamplifier and this translates into a requirement of large memory length L, in order to avoid truncation effects that lead to lack of fit of the model. The new model introduced here is called the composite Volterra model and it requires a moderate memory length and deals with the extended ISI using a linear model. The composite Volterra model is shown to provide a good fit to measured signals with various amounts of nonlinearities and using the composite Volterra model, one is able to synthesize a readback signal with appropriate nonlinearities for any given input data pattern.
Acetylphosphate: A Novel Link between Lysine Acetylation and Intermediary Metabolism in Bacteria

In this issue of Molecular Cell, Weinert et al. (2013) demonstrate that the intermediary metabolite acetyl-phosphate is an important acetyl donor that contributes to global protein acetylation in growth-arrested E. coli.
Decentralized prioritized planning in large multirobot teams

In this paper, we address the problem of distributed path planning for large teams of hundreds of robots in constrained environments. We introduce two distributed prioritized planning algorithms: an efficient, complete method which is shown to converge to the centralized prioritized planner solution, and a sparse method in which robots discover collisions probabilistically. Planning is divided into a number of iterations, during which every robot simultaneously and independently computes a planning solution based on other robots' path information from the previous iteration. Paths are exchanged in ways that exploit the cooperative nature of the team and a statistical phenomenon known as the “birthday paradox”. Performance is measured in simulated 2D environments with teams of up to 240 robots. We find that in moderately constrained environments, these methods generate solutions of similar quality to a centralized prioritized planner, but display interesting communication and planning time characteristics.
Non-invasive estimation of jugular venous oxygen saturation: a comparison between near infrared spectroscopy and transcutaneous venous oximetry

The ability of practitioners to assess the adequacy of global oxygen delivery is dependent on an accurate measurement of central venous saturation. Traditional techniques require the placement of invasive central venous access devices. This study aimed to compare two non-invasive technologies for the estimation of regional venous saturation (reflectance plethysmography and near infrared spectroscopy [NIRS]), using venous blood gas analysis as gold standard. Forty patients undergoing cardiac surgery were recruited in two groups. In the first group a reflectance pulse oximeter probe was placed on the skin overlying the internal jugular vein. In the second group, a Somanetics INVOS oximeter patch was placed on the skin overlying the internal jugular vein and overlying the ipsilateral cerebral hemisphere. Central venous catheters were placed in all patients. Oxygen saturation estimates from both groups were compared with measured saturation from venous blood. Twenty patients participated in each group.Data were analyzed by the limits of agreement technique suggested by Bland and Altman and by linear regression analysis. In the reflectance plethysmography group, the mean bias was 4.27% and the limits of agreement were 58.3 to -49.8% (r(2) = 0.00, p = 0.98). In the NIRS group the mean biases were 10.8% and 2.0% for the sensors attached over the cerebral hemisphere and over the internal jugular vein, respectively, and the limits of agreement were 33.1 to -11.4 and 19.5 to -15.5% (r(2) = 0.22, 0.28;p = 0.04, 0.03) for the cerebral hemisphere and internal jugular sites, respectively. While transcutaneous regional oximetry and NIRS have both been used to estimate venous and tissue oxygen saturation non-invasively, the correlation between estimates of ScvO(2) and SxvO(2) were statistically significant for near infrared spectroscopy, but not for transcutaneous regional oximetry. Placement of cerebral oximetry patches directly over the internal jugular vein (as opposed to on the forehead) appeared to approximate internal jugular venous saturation better (lower mean bias and tighter limits of agreement), which suggests this modality may with refinement offer the practitioner additional clinically useful information regarding global cerebral oxygen supply and demand matching.
Association between the serum anion gap and blood pressure among patients at Harvard Vanguard Medical Associates.

Association between the serum anion gap and blood pressure among patients at Harvard Vanguard Medical Associates
Rate Controlled Constrained-Equilibrium (RCCE) Method Applied to Di-Methyl Ether (DME) Combustion

The rate-controlled constrained-equilibrium technique is used to study the ignition characteristics of Di-Methyl Ether (DME) under high pressure, low temperature in a batch reactor. A set of 9 constraints was identified which is able to exactly reproduce the ignition characteristics within the specified range of thermo dynamics conditions. The detailed kinetic scheme involves C1 -C2 chemistry and comprises 54 species and 308 reactions without nitrogen chemistry.© 2008 ASME
Feature classification techniques in model-based object recognition

We describe a system that performs model-based recognition of the projections of generalized cylinders, and present new results on the final classification of the feature data. Two classification methods are proposed and compared. The first is a Bayesian technique that ranks the object space according to estimated conditional probability distributions. The second technique is a new feed-forward “neural” implementation that utilizes the back-propagation learning algorithm. The neural approach yields a 31.8% reduction in classification error for a database of twenty models relative to the Bayesian approach, although it does not provide an ordered ranking of the object space. The accuracy results of the neural approach represent a significant performance advance in feature-based recognition by perceptual organization without the use of depth information. Examples are provided using the results of a simple segmentation system applied to real image data.
Intracardiac thrombus-in-transit characterized on 3-dimensional transesophageal echocardiography.

A 60-year-old woman presented with fever and shortness of breath of one week's duration. Physical examination disclosed a right-lower-quadrant abdominal mass and pretibial edema. A chest computed tomogram showed bilateral pulmonary embolism, and venous Doppler ultrasonographic imaging of the lower extremities revealed acute deep vein thrombosis (DVT) of the right common femoral vein. Abdominal ultrasonograms showed a large right ovarian mass. A 2-dimensional transthoracic echocardiogram (2D TTE) showed an echogenic mass in the atria. Two-dimensional transesophageal echocardiograms (TEE) revealed an aneurysmal interatrial septum and a large, mobile mass in the right atrium. The mass was in transit through a patent foramen ovale and extended into the left atrium (Fig. 1). Three-dimensional (3D) TEE helped to characterize the mass as a thrombus-intransit that extended through the interatrial septum (Fig. 2). Upon sequential cropping of the images, echolucent components seen inside the mass were consistent with an intracardiac thrombus.1 The ovarian mass was found to be malignant. The patient was prescribed long-term anticoagulation. After 6 months, 2D TTE revealed complete resolution of the thrombus and no evidence of left-sided emboli. Fig. 1 Two-dimensional transesophageal echocardiograms show an aneurysmal interatrial septum and the large intracardiac thrombus (arrows) in A) apical 4-chamber view and B) short-axis view at the aortic valve level. Fig. 2 Three-dimensional transesophageal echocardiograms show the intracardiac thrombus-in-transit (arrows) at the levels of A) the interatrial septum and B) the mitral valve.
Enhancement of two-dimensional spectra such as INADEQUATE by application of symmetry rules

Several years ago it was demonstrated that carbon-carbon connectivities could be determined at natural abundance by use of double-quantum spectroscopy (1-4). This procedure only detects those sites which have adjacent carbon13 nuclei. The correlation information so obtained can be useful not only in assigning the carbon-l 3 spectra but also in providing a powerful method for investigating molecular structures. The experiment, which is known as INADEQUATE, suppresses signals from isolated carbon13 sites by exploiting phase cycling to detect only those signals which arise from double-quantum coherence. The INADEQUATE family of experiments potentially offers a great deal of easily interpretable information about molecules in solution. The main problem with this approach has been known ever since the experiment was first proposed and it is sensitivity. Since the INADEQUATE experiment only detects one site in about 1 04, when using carbon-13 at natural abundance, the sensitivity is very low. W ith currently available high-field spectrometers the limiting concentration is about 0.1 Mor so for an overnight run. Relay transfer experiments (5-8) have supplanted INADEQUATE experiments, to a large extent, due to their much higher sensitivity. To improve the sensitivity of INADEQUATE much beyond the forms already presented (Z-4) essentially only two approaches seem viable. One would be to develop a proton detection version. However, this approach does not seem fruitful since protonated carbon sites can be interrogated via proton detection relay transfer experiments (8) and the suppression of unwanted signals seems daunting. In INADEQUATE experiments the signals to be suppressed, from isolated carbon13 sites, are only about 100 times as intense as those from doubly labeled sites. However, for proton detection to be successful the signals from carbon-12 sites need to be suppressed and these are lo4 more common than doubly labeled sites. In practice this would require 105-fold or so suppression of the unwanted signals which may be obtainable but not without a very stable spectrometer. The other possible approach is to develop techniques to enhance the data from existing forms of the INADEQUATE experiment, in particular, to further develop and apply the techniques recently demonstrated to enhance two-dimensional spectra
Molecular cloning and characterization of a tyrosine phosphatase from Monosiga brevicollis.

Abstract Protein tyrosine phosphorylation is thought to be a unique feature of multicellular animals. Interestingly, the genome of the unicellular protist Monosiga brevicollis reveals a surprisingly high number and diversity of protein tyrosine kinases, protein tyrosine phosphatases (PTPs), and phosphotyrosine-binding domains. Our study focuses on a hypothetical SH2 domain-containing PTP (SHP), which interestingly has a predicted structure that is distinct from SHPs found in animals. In this study, we isolated cDNA of the enzyme and discovered that its actual sequence was different from the predicted sequence as a result of non-consensus RNA splicing. Contrary to the predicted structure with one SH2 domain and a disrupted phosphatase domain, Monosiga brevicollis SHP (MbSHP) contains two SH2 domains and an intact PTP domain, closely resembling SHP enzymes found in animals. We further expressed the full-length and SH2 domain-truncated forms of the enzyme in Escherichia coli cells and characterized their enzymatic activities. The double-SH2 domain-truncated form of the enzyme effectively dephosphorylated a common PTP substrate with a specific activity among the highest in characterized PTPs, while the full-length and the N-terminal SH2 domain-truncated forms of the enzyme showed much lower activity with altered pH dependency and responses to ionic strength and common PTP inhibitors. This indicates that SH2 domains suppress the catalytic activity. SHP represents a highly conserved ancient PTP, and studying MbSHP should provide a better understanding about the evolution of tyrosine phosphorylation.
Characterization of the Mycobacterium tuberculosis iniBAC Promoter, a Promoter That Responds to Cell Wall Biosynthesis Inhibition

ABSTRACT The cell wall provides an attractive target for antibiotics againstMycobacterium tuberculosis. Agents such as isoniazid and ethambutol that work by inhibiting cell wall biosynthesis are among the most highly effective antibiotics against this pathogen. Although considerable progress has been made identifying the targets for cell wall active antibiotics, little is known about the intracellular mechanisms that are activated as a consequence of cell wall injury. These mechanisms are likely to have an important role in growth regulation and in the induction of cell death by antibiotics. We previously discovered three isoniazid-induced genes (iniB,iniA, and iniC) organized in tandem on theM. tuberculosis genome. Here, we investigate the unique features of the putative iniBAC promoter. This promoter was specifically induced by a broad range of inhibitors of cell wall biosynthesis but was not inducible by other conditions that are toxic to mycobacteria via other mechanisms. Induction required inhibitory concentrations of antibiotics and could be detected only in actively growing cells. Analysis of the iniBAC promoter sequence revealed both a regulatory element upstream and a potential repressor binding region downstream of the transcriptional start site. The induction phenotype and structure of the iniBAC promoter suggest that a complex intracellular response occurs when cell wall biosynthesis is inhibited in M. tuberculosis and other mycobacteria.
Generalized Approach to Split and Merge Segmentation on Parallel Architectures

Parallel computers are playing an increasingly important role in areas such as fluid dynamics, particle physics, simulation, and computer vision. In particular, regular data structures and the complexity of computation of most computer vision algorithms make them ideally suited for implementation in parallel computers. In the past, most parallel algorithms have been developed for a given target architecture. Recently, generalized approaches to parallel program design, where architectural issues are postponed to the last step of the design process, have been gaining momentum in the research community. A formal approach for the design of parallel programs is to iteratively refine the specifications. In this paper, we demonstrate the use of this approach to split and merge method of segmentation. The starting point for the design is the general specifications of the divide-and-conquer paradigm, and the end result is the design of a program for the split and merge segmentation on a hypercube architecture. The performance is evaluated in terms of speed-up and efficiency of the processors.
Increased Serum Levels of a Parathyroid Hormone-like Protein in Malignancy-Associated Hypercalcemia

Abstract Study Objective:To measure the serum levels of a newly described parathyroid hormone-like protein (PLP), which was isolated from malignant tumors associated with hypercalcemia, and determi...
Writing Material in Chemical Physics Research: The Laboratory Notebook as Locus of Technical and Textual Integration

This article, drawing on ethnographic study in a chemical physics research facility, explores how notebooks are used and produced in the conduct of laboratory science. Data include written field no...
SU‐FF‐T‐344: Perturbation to Dose Distribution Caused by Utilizing An MLC Instead of a Brass Aperture in Passive Scattering Proton Therapy

Purpose: To evaluate the perturbation to dose distribution caused by utilizing a tungstenMLC instead of a brass aperture in passive scattering proton therapy.Method and Materials: A four‐dimensional GEANT4 Monte Carlo simulation of a proton therapy nozzle is used to simulate the behavior of a beam delivery system. Several datasets have been generated accounting for different configurations of system components including binary pre‐scatterer foils, double contoured scatterer, modulator wheel, and pre‐collimator jaws. The resulting beam profiles are subject to one of two different final collimator options: a tungstenMLC or a brass aperture. The performance of the beam delivery system is examined for different beam energies, intensity modulation patterns, field size, air gap between the MLC and the patient, and the introduction of a step in the design of the MLC.Results: We quantify dosimetric perturbations when conforming to a simple target volume. Variations in several factors were studied, including lateral field flatness and symmetry, penumbra, and flatness of the spread‐out Bragg peak. When compared to results obtained using a brass aperture, an MLC made of tungsten seems to produce similar results. Additionally, the respective neutron energy distributions were used to calculate the neutron equivalent dose absorbed outside of the treatment field in each case. Conclusion: The ability of an MLC to conform to target volume is a function of the specific contour shape. This is not necessarily true for a custom made aperture. However, our analysis of dosimetric differences between the two indicates that there are no significant differences for simple target volume contours. The performance of an MLC as a final collimator in passive scattering proton therapy is predicted to be comparable to the performance of a brass aperture. Furthermore, secondary neutron production is reduced by using a tungstenMLC rather than a brass aperture.
Reductions in neuronal density in elderly depressed are region specific.

Objective Frontal regions, including the orbitofrontal cortex (ORB) and dorsolateral prefrontal cortex (dlPFC) have been implicated in the neuropathology of geriatric depression. Prominent reductions in pyramidal neuron density have been recently reported in the ORB of older depressed subjects. However, the cellular pathology of the dlPFC has not yet been examined in these subjects. Methods Postmortem tissue from the dlPFC (Brodmann's area 9, BA9) was collected from 10 older (>60 years old) subjects diagnosed with major depression and 10 age-matched non-psychiatric controls (CTRL). The majority of the subjects were the same as those used for our previous study on neuronal reductions in the ORB in older depressed. Overall (all six layers combined), and laminar density of pyramidal (presumably glutamatergic), and non-pyramidal (GABAergic) neurons as well as cortical and laminar width were measured using linear optical disector of Stereoinvestigator software. Results Neither the overall nor laminar density of pyramidal or non-pyramidal neurons was significantly different between groups. The cortical and laminar widths were also not affected. Conclusions These results suggest that neuronal prefrontal pathology in elderly depressed is region specific. No significant changes were detected in the density of any type of neurons in the dlPFC of elderly depressed subjects (present study) whereas, prominent reductions in the density of pyramidal glutamatergic neurons were observed previously in the ORB. Copyright © 2009 John Wiley & Sons, Ltd.
Degradation of CL-20 by white-rot fungi.

Abstract In previous studies, we found that the emerging energetic chemical, CL-20 (C6H6N12O12, 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane), can be degraded following its initial denitration using both aerobic and anaerobic bacteria. The C and N mass balances were not determined due to the absence of labeled starting compounds. The present study describes the degradation of the emerging contaminant by Phanerochaete chrysosporium using ring-labeled [15N]-CL-20 and [14C]-CL-20. Ligninolytic cultures degraded CL-20 with the release of nitrous oxide (N2O) in amounts corresponding to 45% of the nitrogen content of CL-20. When ring-labeled [15N]-CL-20 was used, both 14N14NO and 15N14NO were observed, likely produced from –NO2 and N–NO2, respectively. The incubation of uniformly labeled [14C]-CL-20 with fungi led to the production of 14CO2 (>80%). Another ligninolytic fungus, Irpex lacteus, was also able to degrade CL-20, but as for P. chrysosporium, no early intermediates were observed. When CL-20 was incubated with manganese peroxidase (MnP), we detected an intermediate with a [M−H]− mass ion at 345 Da (or 351 and 349 Da when using ring-labeled and nitro-labeled [15N]-CL-20, respectively) matching a molecular formula of C6H6N10O8. The intermediate was thus tentatively identified as a doubly denitrated CL-20 product. The concomitant release of nitrite ions ( NO 2 - ) with CL-20 degradation by MnP also supported the occurrence of an initial denitration prior to cleavage and decomposition.
Safety and efficacy of concomitant carotid and coronary artery operations

Background. Controversy exists concerning the best management for patients with concurrent severe carotid and coronary artery disease. Methods. The records of 200 consecutive patients having concurrent carotid endarterectomy and coronary artery bypass grafting from 1979 to 1993 were reviewed, and follow-up was obtained (99% complete). Of the group (77% male; mean age, 67 years), 134 (67%) had unstable angina, 130 (65%) had triple-vessel disease, and 86 (43%) had left main coronary stenosis. Preoperative investigation revealed asymptomatic bruits in 116 (58%), transient ischemia in 65 (32%), strokes in 31 (16%), and bilateral carotid disease in 44 patients (22%). Nonelective operations were required in 66 patients (33%). Results. Hospital death occurred in 7 patients (3.5%), myocardial infarction in 5 (2.5%), and permanent stroke in 6 (3%). Ten-year actuarial event-free rates were as follows: death, 58%; myocardial infarction, 81%; stroke, 92%; percutaneous angioplasty, 98%; redo coronary artery grafting, 94%; and all morbidity and mortality, 56%. Significant multivariate predictors of hospital death were postoperative stroke, failure to use an internal mammary artery graft, intraoperative intraaortic balloon, and nonelective operation. Significant predictors of postoperative stroke were peripheral vascular disease and unstable angina. Significant predictors of prolonged hospital stay were postoperative stroke, advanced age, and nonelective operation. Conclusions. Concomitant carotid endarterectomy and coronary bypass grafting can be performed with acceptably low operative risk and good long-term freedom from coronary and neurologic events.
Inhomogeneous Static Model in Brans-Dicke Theory

A static universe with position-dependent rest-energy density, pressure, and scalar field is considered in Brans-Dicke theory. A perfect-gas equation of state is obtained with the solution to the field equations for the Euclidean case with Robertson-Walker metric.
General synthesis for chiral 4-alkyl-4-hydroxycyclohexenones.

Some selective transformations of resorcinol-derived cyclohexadienone are reported. Efforts led to a structure reported to display anticancer properties. On the basis of the results, the structures for natural products reported to contain a 4,6-dihydroxy-4-alkyl-cyclohexenone nucleus are corrected.
Transcriptional profiles of leukocyte populations provide a tool for interpreting gene expression patterns associated with high fat diet in mice.

Background: Microarray experiments in mice have shown that high fat diet can lead to elevated expression of genes that are disproportionately associated with immune functions. These effects of high fat (atherogenic) diet may be due to infiltration of tissues by leukocytes in coordination with inflammatory processes. Methodology/Principal Findings: The Novartis strain-diet-sex microarray database (GSE10493) was used to evaluate the hepatic effects of high fat diet (4 weeks) in 12 mouse strains and both genders. We develop and apply an algorithm that identifies ‘‘signature transcripts’’ for many different leukocyte populations (e.g., T cells, B cells, macrophages) and uses this information to derive an in silico ‘‘inflammation profile’’. Inflammation profiles highlighted monocytes, macrophages and dendritic cells as key drivers of gene expression patterns associated with high fat diet in liver. In some strains (e.g., NZB/BINJ, B6), we estimate that 50–60% of transcripts elevated by high fat diet might be due to hepatic infiltration by these cell types. Interestingly, DBA mice appeared to exhibit resistance to localized hepatic inflammation associated with atherogenic diet. A common characteristic of infiltrating cell populations was elevated expression of genes encoding components of the tolllike receptor signaling pathway (e.g., Irf5 and Myd88). Conclusions/Significance: High fat diet promotes infiltration of hepatic tissue by leukocytes, leading to elevated expression of immune-associated transcripts. The intensity of this effect is genetically controlled and sensitive to both strain and gender. The algorithm developed in this paper provides a framework for computational analysis of tissue remodeling processes and can be usefully applied to any in vivo setting in which inflammatory processes play a prominent role.
The early development of the parotid gland around the facial nerve and its branches in man

The manner in which the parotid gland forms around the related facial nerve branches was studied with the aid of reconstructions in 15 human embryos and fetuses 18 to 80 mm, crown-rump length, 7+ to 13.5 weeks (w), menstrual age. Peripheral branches of the nerve terminate in the cervicomandibular region at 18 mm (7+w), when the unbranched parotid bud is farther rostral. By 22 mm (8w), a small nerve branch approaches the buccal region superficial to the bud that extends toward the preauricular region. At 26 mm (8.5w), several nerve branches course superficial to the parotid primordium which has first order ductules and is adjacent to the masseter muscle. Second order ductules form quickly (27 mm, 8.5w) as the primordium approaches the superficial aspect of the lower buccal, marginal mandibular and cervical nerve branches. The primordium enters the parotid space by 32 mm (9w) as third order ductules develop. At 37 mm (10w), it has fourth order ductules and the buccal nerve branches are superficial to the main duct. Nerve branches of the temporofacial ramus (temporal, zygomatic and upper buccal) occupy a superficial position in the primordium whereas branches of the cervicofacial ramus (lower buccal, marginal mandibular and cervical) are deeper. A similar arrangement is evident at 56–80 mm (11.5–13.5w) when the complex primordium has connections with its superficial and deep portions between many nerve branches.
Scalability in real-time systems with end-to-end requirements

Abstract The stringent demands to guarantee task deadlines in real-time systems have motivated both practitioners and researchers to look at ways to analyze systems prior to run-time. This paper reports a new perspective of analyzing real-time systems that in addition to ascertaining the ability of a system to meet task deadlines also qualifies these guarantees. The guarantees are qualified by a measure (called the scaling factor) of the system's ability to continue to provide these guarantees under possible changes to the tasks. This measure is shown to have many applications in the design (task execution time estimation), development (portability and fault tolerance) and maintenance (scalability) of real-time systems. The derivation of this measure in end-to-end systems requires that we solve two fundamental problems — the uni-processor schedulability problem and the uni-processor scalability problem. The uni-processor schedulability problem involves finding whether a set of tasks (with arbitrary non-zero arrival times) will meet its deadlines. The scalability problem seeks to find the maximum scaling factor with which the execution times of a set of tasks can be scaled without invalidating its schedulability. Optimal solutions to these two fundamental problems are presented.
Vegetation affects hillslope hydrodynamics

Hillslopes are an important part of the hydrological cycle because water from rainfall or snowmelt runs downhill to networks of streams. Understanding hillslope hydrological dynamics is important for flood and debris flow prediction. However, because hillslopes are highly varied, developing general frameworks for analyzing them is difficult.Bachmair et al. compared three hillslopes to try to synthesize understanding of subsurface flow processes at the hillslope scale, focusing on the effect of vegetation.
Chromosome location of genes affecting polyphenol oxidase activity in seeds of common and durum wheat

This study used cytogenetic stocks to investigate the chromosomal location of genes responsible for polyphenol oxidase (PPO) activity in common and durum wheat seeds. Substitution lines of chromosome 2A of hexaploid varieties 'Cheyenne', 'Thatcher' and 'Timstein' in 'Chinese Spring' showed significantly higher PPO activity than all other substitution lines of the same variety, with the exception of substitutions of 'Cheyenne' chromosome 3A and 'Thatcher' chromosome 4B. Substitution lines of chromosome 2A of Triticum turgidum var. dicoccoides and of chromosome 2D of 'Chinese Spring' into the tetraploid variety 'Langdon' showed a significant increase in PPO activity relative to all other substitution lines in Langdon. The gene(s) responsible for high PPO activity in chromosome 2D from 'Chinese Spring' was mapped on the long arm within a deletion that represents 24% of the distal part of the arm. This study shows that genes located in homoeologous group 2 play a major role in the activity of PPO in wheat.
Cross‐system comparisons of soil nitrogen transformations and nitrous oxide flux in tropical forest ecosystems

Soil nitrogen transformations and nitrous oxide flux across the soil-air interface were measured in a range of tropical forest sites in Costa Rica, Brazil, and Hawaii. Nitrogen mineralization and nitrification potentials were high in the relatively fertile Costa Rica sites and the Amazonian oxisol/ultisols (>1.5 μg g−1 d−1 of N mineralized), intermediate in Amazonian white sand soils (0.5-0.8 μg g−1 d−1) and low in the Hawaiian montane sites (<0.5 μg g−1 d−1). Nitrous oxide fluxes ranged from 0 to 6.2 ng cm−2 h−1 of N; mean flux per site was highly correlated with mean nitrogen mineralization across 26 sites. These correlated patterns of nitrogen cycling and trace gas production could be useful in the development of regional- and global-scale estimates of nitrous oxide fluxes from tropical forests.
Analysis of apoplastic solutes in the cortex of soybean nodules.

Various techniques were used to extract solutes from the free space of intact soybean [Glycine max (L.) Merr.] nodules. A variety of solutes (carbohydrates, amino acids, organic acids, ions) was found, but the major solute obtained with all methods was allantoic acid. Most work was done with a technique involving vacuum infiltration of intact detached nodules with water. This approach provided rapid sampling of the apoplastic solutes, and the results indicated that solutes were not derived from the xylem and phloem of ruptured vascular bundles. Infiltration of intact nodules with Fast Green showed dye penetration only to the barrier in the inner cortex, indicating that infected tissues did not contribute to solute composition. Although allantoic acid was the only ureide which could be detected in solute samples, no evidence was obtained for the presence of allantoinase in the cortical apoplast. The results suggest the transport of allantoic acid by an apoplastic route in nodules or the release of allantoic acid to the cortical apoplast in response to treatments which disrupt ureide export. Calculated values for solute concentrations in the cortical apoplast were in the hundred millimolar range, suggesting that apoplastic solutes may represent a significant osmotic component in the nodule cortex.
The dermatology workforce shortage.

Abstract Background While many dermatology workforce projections over the past two decades forecasted an impending oversupply, more recent reports have begun to suggest a shortage of dermatologic services. Methods Anonymous surveys administered to practicing dermatologists and to recent training graduates were examined for surrogate indicators of the supply and demand for dermatologic services. Results The mean wait time for new patient appointments with dermatologists was 36 calendar days, but ranged widely based on location (means ranged from 9-120 days by state). About half (49%) of practicing dermatologists feel that they need more dermatologists in their communities, while only 20% describe the local supply as too high. The reported need for medical and general dermatologists is far more acute than for dermatologic subspecialists. Many practices (33%) are looking for new associates, and not surprisingly, most new graduates entering the workforce over the past 4 years (86-93%) do not describe any difficulty finding desirable positions. Fewer than 10% of recent graduates are dissatisfied with their current jobs. Conclusion Based on survey data examining wait times, physician perception, use of physician extenders, searches for new employees, and experience of recent graduates entering the workforce, it appears there is an inadequate supply of dermatologists to meet the demand for services.
Fetal fibronectin levels are elevated in maternal plasma and amniotic fluid of patients with severe preeclampsia.

Abstract OBJECTIVE: Our purpose was to investigate levels of fetal fibronectin in maternal plasma, amniotic fluid, and umbilical cord plasma from patients with severe preeclampsia. STUDY DESIGN: The study group comprised 20 patients with severe preeclampsia (group A). An antopartum comparison group was composed of 20 healthy patients matched for gestational age (group B). An intrapartum control group consisted of 20 term normotensive patients (group C). Maternal plasma samples were collected before labor (groups A and B), then immediately after delivery, and again at 20 to 24 hours post partum (groups A and C). Amniotic fluid was also collected in early labor, and umbilical cord blood was collected at delivery (groups A and C). Samples were assayed for fetal fibronectin by a specific enzyme-linked immunoassay. RESULTS: Before labor maternal plasma levels of fetal fibronectin were significantly elevated in preeclamptic patients compared with patients in group B ( p p p p CONCLUSIONS: Fetal fibronectin is elevated in the maternal plasma and amniotic fluid, but not umbilical cord plasma, of patients with severe preeclampsia. These findings suggest an increase in production of fetal fibronectin from chorionic trophoblasts in patients with preeclampsia or an abnormal interaction between chorionic trophoblast and decidua with reusltant increased leakage into the maternal circulation and amniotic fluid.
Differences in personal, cognitive, psychological, and social factors associated with drug and alcohol use and nonuse by homeless women

The purpose of this study was to compare differences in personal, cognitive, behavioral, psychological, and social variables among homeless women who were current drug or alcohol users, or both, past drug or alcohol users, or both, and those who never used drugs or alcohol. The sample consisted of 1,013 women residing in 73 Los Angeles homeless shelters. Depression, anxiety, hostility, emotion-focused coping, lower self-esteem, and less social support were more prevalent among homeless women who continued to use drugs and alcohol than among past users or those who never used. AIDS knowledge was higher among past users. The results contribute important knowledge regarding the pattern of cognitive, psychological, and social differences between users and nonusers.
Realization of hybrid compressive imaging strategies

The tendency of natural scenes to cluster around low frequencies is not only useful in image compression, it also can prove advantageous in novel infrared and hyperspectral image acquisition. In this paper, we exploit this signal model with two approaches to enhance the quality of compressive imaging as implemented in a single-pixel compressive camera and compare these results against purely random acquisition. We combine projection patterns that can efficiently extract the model-based information with subsequent random projections to form the hybrid pattern sets. With the first approach, we generate low-frequency patterns via a direct transform. As an alternative, we also used principal component analysis of an image library to identify the low-frequency components. We present the first (to the best of our knowledge) experimental validation of this hybrid signal model on real data. For both methods, we acquire comparable quality of reconstructions while acquiring only half the number of measurements needed by traditional random sequences. The optimal combination of hybrid patterns and the effects of noise on image reconstruction are also discussed.
The Change in Earth-Atmosphere Albedo and Radiational Equilibrium Temperatures due to Stratospheric Pollution.

Abstract The changes in the earth-atmosphere albedo and radiative equilibrium temperature due to perturbations in the solar radiative balance are investigated. The perturbations are induced through the introduction of varying amounts of aerosols into the stratospheric layer between 15 and 25 km. Results are presented graphically as a function of latitude and season for a range of aerosol absorption coefficients and for a specific aerosol composed of a 75% sulphuric acid solution. These results indicate that such aerosol perturbations on the solar energy field result in larger albedo and radiative equilibrium changes in polar latitudes than in middle or tropical latitudes.
Suggest-Choose-Plan-Compose: A Strategy to Help Students Learn to Write

This article describes a strategy to support students' development of creative writing and construction of text in a sequential manner. The goal of the Suggest-Choose-Plan-Compose (SCPC) strategy is to improve students' ability to create a story by helping them clarify their thoughts as they generate and organize ideas and basic story elements. SCPC implements various grouping patterns and a careful approach to the removal of teacher support. By deliberately planning and engaging students in the stages within SCPC, they can produce well crafted-writing.
Specificity Analysis of Antibodies Formed in Rabbits to a Mannosyl Trisaccharide: Similarity with Lectin Binding Activity Para-Aminophenyl O-α-D-Mannopyranosyl-(1→2)-α-D-Mannopyranosyl-(1→6)-α-D-Mannopyranoside Linked to Bovine Serum Albumin as an Antigen

The para-aminophenyl derivative of Manα1→2Manα1→6Manα1→ was coupled via a diazotization reaction to bovine serum albumin, and the resulting glycoconjugate was used to immunize two rabbits. The resultant antisera were tested for reactivity with a number of related mono, di- and trisaccharides to determine the immunodominant portion of this trisaccharide. Two populations of antibody resulted, one of which required the reducing end mannose, and could react with either an N-acetylglucosamine or a mannose as the penultimate sugar. The other population reacted with the Manα1→2Manα1→6Manα1→. The aglycone moiety and its configurations play an important role in determining the specificity of antibodies to this synthetic antigen. The similarity of this reactivity to the reactivity of mannose binding lectins is discussed.
Energy behavior with magnetic field of negatively charged magnetoexcitons in quantum wells and heterojunctions

We present the results of the magneto-photoluminescence measurements performed on modulation doped GaAs/AlGaAs heterostructures in high magnetic fields (up to 60T) and low temperatures (0.37−1.5K). With increasing magnetic field we observe the formation of the triplet and singlet states of negatively charged magneto-excitons (X − ) in addition to the neutral exciton (X 0 ). Their behavior with field strongly depends on the sample geometry. In the case of a modulation doped quantum well (QW) with a well-width of 200A, the and states cross at a magnetic field of about 40T, whereas for a modulation-doped single heterojunction (SHJ) these states show no crossing over the whole range of available fields.
Monitoring and comparison to predictive models of the Perdido Key beach nourishment project, Florida, USA

Abstract This paper summarizes the results of over 8 years of data describing the performance of a large beach nourishment project on Perdido Key, immediately adjacent to Pensacola Pass in Escambia County, FL, USA. As a result of a major excavation of the entrance channel to Pensacola Bay, over 7 million m3 of beach-quality sand were placed along the easternmost 7.5 km of Perdido Key, adjoining the entrance channel at Pensacola Pass. The project included the placement of 4.1 million m3 of sand directly upon the shoreline in 1989–1990, followed by the placement of an additional 3 million m3 as an underwater berm just offshore of the beach nourishment project in water depths of roughly 6 m. Monitoring of the performance of the beach nourishment project and the offshore berm has been conducted since 1989, beginning with a pre-construction survey of the project area. Monitoring surveys have been conducted on an annual or biennial basis since that time, with the most recent survey occurring in July/August, 1998. Over 8 years of monitoring data indicate that the beach nourishment project has retained approximately 56% of the original volume placed within the 7.5-km project length. In addition, according to the latest monitoring survey, the dry beach width of the project, initially constructed as 135 m on average, is still 53 m wider than pre-project conditions. Approximately 41% of the originally placed dry planform area remains as of July 1998. The most recent monitoring surveys in 1995, 1997, and 1998 encompass the effects of two major storm systems, Hurricanes Erin (August 1995) and Opal (October 1995). Monitoring of the offshore berm area indicates only a slight landward migration of the berm, accompanied by a minor decrease in volume, over the entire monitoring period. The performance of both the beach nourishment project and the offshore berm appear to be significantly related to the two storm events, particularly Hurricane Opal, and the proximity of the project to the tidal entrance at Pensacola Pass. Comparison of the documented performance of the beach nourishment project to simple existing analytical models of beach-fill evolution have yielded encouraging results in terms of preliminary design aids for future beach nourishment projects in the vicinity of deep tidal entrances.
SCREENING FOR SIGNIFICANT ASYMPTOMATIC BACTERIURIA BY A SIMPLE CULTURE METHOD: A Pilot Study on 1136 Children

EDITORIAL SYNOPSIS This study attempts to assess the value of a simple urinary culture method (the filter strip technique) using fresh but not ‘clean voided urine’in detecting asymptomatic urinary infection in children. In 91 of 1136 asymptomatic patients high urinary bacterial counts were found. Testing of these using ‘clean voided urine’and the ‘pour plate’culture technique yielded 4 children with abnormally high colony counts. Further investigation showed that there was a minor abnormality in the urinary tract in each of the 4 patients. The filter strip technique is considered valuable as a cheap and simple screening test.
Behavioral characterization of mice deficient in the phosphodiesterase-10A (PDE10A) enzyme on a C57/Bl6N congenic background.

Abstract The phenotype of genetically modified animals is strongly influenced by both the genetic background of the animal as well as environmental factors. We have previously reported the behavioral and neurochemical characterization of PDE10A knockout mice maintained on a DBA1LacJ (PDE10ADBA) genetic background. The aim of the present studies was to assess the behavioral and neurochemical phenotype of PDE10A knockout mice on an alternative congenic C57BL/6N (PDE10AC57) genetic background. Consistent with our previous results, PDE10AC57 knockout mice showed a decrease in exploratory locomotor activity and a delay in the acquisition of conditioned avoidance responding. Also consistent with previous studies, the elimination of PDE10A did not alter basal levels of striatal cGMP or cAMP or affect behavior in several other well-characterized behavioral assays. PDE10AC57 knockout mice showed a blunted response to MK-801, although to a lesser degree than previously observed in the PDE10ADBA knockout mice, and no differences were observed following a PCP challenge. PDE10AC57 knockout mice showed a significant change in striatal dopamine turnover, which was accompanied by an enhanced locomotor response to AMPH, These studies demonstrate that while many of the behavioral effects of the PDE10A gene deletion appear to be independent of genetic background, the impact of the deletion on behavior can vary in magnitude. Furthermore, the effects on the dopaminergic system appear to be background-dependent, with significant effects observed only in knockout mice on the C57BL6N genetic background.
Preservation of cardiac extracellular matrix by passive myocardial restraint: an emerging new therapeutic paradigm in the prevention of adverse remodeling and progressive heart failure.

Congestive heart failure is a burgeoning problem, especially in older adults, affecting nearly 0.1% of subjects >65 years old, accounting for nearly 20% of all hospitalizations in this age group, and costing the healthcare system a bundle.1 Several experimental observations have demonstrated an important role for progressive dilation and geometric remodeling of the left ventricle in worsening cardiac pump function.2 The results of experimental studies on the adverse implications of ventricular dilation and remodeling have been confirmed in clinical and epidemiological studies of depressed ventricular function and congestive heart failure in humans.2,3 Studies of the natural history of left ventricular dysfunction provide evidence to directly implicate left ventricular dilation and remodeling to an adverse clinical outcome in patients with congestive heart failure. Ventricular dilation and remodeling impose an increased mechanical disadvantage to the pump function by increasing wall stress and consequently the hemodynamic load and by contributing to mitral regurgitation and possibly arrhythmogenesis in patients with congestive heart failure independently of the neurohormonal status. Therapeutic trials have also shown that the majority of clinically useful and approved treatment modalities in heart failure attenuate or reverse ventricular dilation and remodeling.4–8 Despite multiple drug therapies, including neurohormonal blockade, progressive ventricular dilation and adverse remodeling frequently continue in many patients with depressed ventricular function. Although orthotopic cardiac transplantation is highly successful in alleviating heart failure and improving survival, limited donor supply, organ rejection, and complications related to immunosuppressive therapy continue to limit the utility of this procedure. In recent years, several new nonpharmacological approaches for attenuation and or reversal of ventricular dilation and remodeling have been introduced, including partial ventricular resection or the Batsita procedure, the endoventricular patch repair or the Dor procedure, and cardiac resynchronization therapy with biventricular pacing.9 The idea for a passive restraining device to …