cssi/SciSciGPT-SciSciNet huggingface dataset:
A commentary on the screened-Oseen, counterion-condensation formalism of polyion electrophoresis.

The use of linear theory, in particular, counterion condensation (CC) theory, in describing electrophoresis of polyelectrolyte chains, is criticized on several grounds. First, there are problems with CC theory in describing the equilibrium distribution of ions around polyelectrolytes. Second, CC theory is used to treat ion relaxation in a linear theory with respect to the polyion charge despite the fact that ion relaxation arises as a consequence of nonlinear charge effects. This nonlinearity has been well established by several investigators over the last 70 years for spherical, cylindrical, and arbitrarily shaped model polyions. Third, current use of CC theory ignores the electrophoretic hindrance as well as the ion relaxation for condensed counterions and only includes such interactions for uncondensed counterions. Because most of the condensed counterions lie outside the shear surface of the polyion (in the example of DNA), the assumption of ion condensation is artificial and unphysical. Fourth, the singular solution, based on a screened Oseen tensor, currently used in the above mentioned theories is simply wrong and fails to account for the incompressibility of the solvent. The actual singular solution, which has long been available, is discussed. In conclusion, it is pointed out that numerical alternatives based on classic electrophoresis theory (J.T.G. Overbeek, Kolloid-Beih, 1943, 54:287-364) are now available.
Undergraduates in a second language: challenges and complexities of academic literacy development

Undergraduates in a second language: challenges and complexities of academic literacy development, by I. Leki, New York, NY, Lawrence Erlbaum Associates, 2007, xiii + 332 pp., £22.99 (paperback), I...
The Influence of Pulsatile Perfusion on the Vascular Properties of the Newborn Lamb Lung

It is not known how the mode of flow alters the resistance properties of the newborn pulmonary circulation. Therefore, we compared the pressure responses of the perfused left pulmonary circulation of 16 newborn lambs with step changes in either pulsatile or steady flow. The slope of the pressure-flow curve differed significantly according to mode of perfusion. The slope of the pressure-flow curve was 0.125 +/- 0.115 mm Hg.mL-1.kg.min for pulsatile flow and 0.484 +/- 0.350 mm Hg.mL-1.kg.min for steady flow perfusion (p less than 0.05). The intercept pressure at zero flow was similar for both modes of flow, being 21.3 +/- 4.9 mm Hg for pulsatile flow compared with 23.8 +/- 11.3 mm Hg for steady flow perfusion. All perfusions with either mode of flow demonstrated flow-dependent decreases in pulmonary vascular resistance. However, the decreases in resistance were greater for pulsatile than for steady flow perfusion. In addition, the steady-perfused lungs demonstrated a significantly greater left lung wet/dry weight ratio than either the left lungs of pulsatile-perfused animals or the intact left lungs of 13 control animals not undergoing experimental perfusion (p less than 0.05). Thus, the mode of flow appears to play a major role in modulating the magnitude and distribution of pulmonary vascular resistance. This factor must be considered when interpreting the physiologic significance of hemodynamic experiments.
The Command of the Faithful in al-Andalus: A Study in the Articulation of Caliphal Legitimacy

In 929, the eighth Umayyad ruler of al-Andalus, ʿAbd al-Rahman III (r. 912–61) formally assumed the exclusive caliphal prerogatives of khuṭba and sikka. After nearly two centuries of independent Umayyad rule in the Iberian peninsula, ʿAbd al-Rahman III issued a circular to his governors directing them to address him forthwith as amīr al-muʾminīn, or Commander of the Faithful, and to ensure that the khuṭba, or Friday sermon, in every congregational mosque invoked his name with this designation. With this he reclaimed the Umayyad dynasty's rights to the caliphal title: “We have understood that to continue not to use this title, which is incumbent upon us, is to allow one of our rights to decay and a firm designation to become lost.” Later the same year, he established a mint in Cordoba and ordered the striking of gold dinars in his name (sikka), resuming the minting of gold coins in al-Andalus, which had been suspended since the overthrow of the Umayyad caliphate in Syria.
Concentration of amino acids in the brain of cobalt-epileptic rat.

SUMMARY The concentrations of 12 amino acids were measured in brains of rats rendered epileptic by implantation of cobalt wire in parietal cortex; at 7 days there was a marked decrease in the level of glutamic acid, aspartic acid and taurine and an increase in lysine and alanine levels at the site of the lesion. In homotopic contralateral cortex 19 days after implantation of cobalt there were no differences from controls. The findings in rats are thus similar to those reported in other species and in epileptogenic cerebral tissue of man. RESUME La concentration de 12 acides amineas a ete mesuree dans les cerveaux de rats rend us epileptiques par implantation de fil de cobalt dans le cortex parietal; au bout de 7 jours, il y avait une diminution marquee du taux ďacide glutamique, ďacide aspartique, de la taurine et une augmentation de la lysine et de ľalanine aľendroit de la lesion. Dans le cortex parietal contro-lateral, 19 jours apres ľimplantation de cobalt il n'y avait pas de difference entre ces rats et les rats de controle. Ce qu'on trouve chez les rats est semblable a ce qu'on trouve dans ďautres especes et dans le tissu cerebral epileptogene de ľhomme. ZUSAMMENFASSUNG Die Konzentration von 12 Aminosauren wurde im Gehirn von Ratten gemessen, bei denen eine Epilepsie durch Implantation eines Kobaltdrahts in den parietalen Kortex erzeugt wurde. Nach 7 Tagen zeigte sich eine deutliche Verminderung der Glutamin-saure, Asparaginsaure und des Taurins sowie eine Zunahme von Lysin und Alanin im Bereich der Lasion. Der entsprechende kontralaterale Kortex zeigte 19 Tage nach der Implantation von Kobalt keinen Unterschied zu Kontrollen. Die Befunde von Ratten ahneln damit denen, die von anderen Tierarten und im epileptogenen Hirngewebe des Menschen erhoben wurden. RESUMEN Se ha determinado la concentration de 12 aminoacidos en los cerebros de ratas convertidas en epilepticas mediante la implantacion de alambre de cobalto en la corteza parietal. En el lugar de implantacion se registro un marcado descenso de los niveles de acido glutamico, acido aspartico y taurina, observandose elevaciones de lisina y alanina. No se encontraron diferencias con los animales control en la corteza homologa contralateral a los 19 dias de la implantacion. Los hallazgos en las ratas son, pues, anaalogos a los publicados en otros animales y en el cerebro epileptogenico humano.
Life history strategies of striped bass, Morone saxatilis, populations inferred from otolith microchemistry

Otolith microchemistry was used to investigate genetic, demographic and life history characteristics of striped bass, Morone saxatilis. Striped bass were collected from three river systems along the eastern seaboard: the Neuse River and Roanoke River, North Carolina, USA and the Stewiacke River, Nova Scotia, Canada. The elemental ratios Mn:Ca, Fe:Ca, Br:Ca, Zn:Ca, Cu:Ca and Sr:Ca were measured in otolith nuclei using broad-beam particle induced X-ray emission (PIXE) spectroscopy. Elemental ratios were not significantly different between several Roanoke River genotypes. Two dorsal coloration patterns found in Stewiacke River striped bass indicate the presence of ocean-going (green) and resident (black) contingents, but results of trace elemental analysis showed no differences in elemental signatures of otolith nuclei suggesting that the contingents originate from the same population. Observed Sr:Ca ratios were not stable between Roanoke River year classes; decreased levels of strontium found in 1 year class corresponded with a flooding event. Discriminant analysis using these six elemental ratios correctly identified approximately 88% of the Neuse River, 79% of Stewiacke River, and 47% of the Roanoke River striped bass to the river system from which they were caught during spawning activity. Misclassified individuals might be a result of environmental variability from subhabitats or represent wandering individuals from other populations. The Neuse River population, which is considered to be an endemic riverine population, had no obvious outliers. Results of this study show the increased power of information gathering provided by otolith microchemistry when used in concert with phenotypic and genotypic classification techniques.
Perturbation analysis of second-order effects in kinetics of oil-shale pyrolysis

Abstract Perturbation techniques are used to develop a procedure for obtaining rate constants in a non-linear model of the kinetics of oil-shale pyrolysis. Assuming that certain substances — kerogen, bitumen, oil and gas — can be measured by an experiment, and that a certain structure governing the chemical reactions is known, the rate constants are determined by a least-squares procedure.
Doctors' consultations with children and their parents: a model of competencies, outcomes and confounding influences.

Context The clinical consultation is an important aspect of the doctor's role. However, there is a particular shortage of methods for assessing its quality, and its complexity makes it a considerable assessment challenge. Research question What are the key components of consultations involving children? Methods (1) A content analysis of relevant published and unpublished literature. (2) A nominal group consensus exercise with experienced paediatricians. Results The content analysis and consensus exercise suggested similar lists of doctor's characteristics, tasks and outcomes as being important components of the consultation. Doctor's characteristics include: clinical judgement, clinical knowledge, physical examination, information gathering, clinical questioning, information giving, patient-centredness, parent-centredness, interpersonal skills, and consultation management. Important tasks include: organisation and efficiency, rapport, information gathering, getting the family perspective, examination and procedures, evaluation, medically appropriate plans, family appropriate plans, enhancing understanding and recall, achieving consensus, sharing responsibility, family knows how to get further help and liaison with other relevant health-care professionals. Important outcomes include: family satisfaction, family perceptions, compliance, health, health-related problems and doctor's satisfaction. The studies reviewed in the literature also provided a catalogue of factors that have been shown to influence the doctor–patient interaction that could potentially confound the assessment of a doctor's performance. These include the doctor's: age, gender, training, speciality, income, social class and politics; the patient's: age, gender, health, prognosis, social class, education, health beliefs and preferences about control and risk. The length of the acquaintance between doctor and patient, and the workload and case-mix in the clinic also affect the interaction. In several studies it is clear that particular combinations of doctor-type and patient-type have especially good or bad interactions. Conclusions and further work These components are synthesised in a single model of the doctor–patient interaction to guide the development and evaluation of assessment instruments aimed at consultations involving children.
The physical limits of grating visibility

We examined the extent to which pre-neural factors constrain the detectability of sinusoidal gratings of different spatial frequencies and luminances. Contrast sensitivity functions were measured in two observers for foveally-presented grating patches. Spatial extent of the patches was inversely proportional to grating frequency. The observers' contrast sensitivity functions were then compared to the performance of an ideal discriminator (Geisler, 1984) which incorporated the effects of quantal fluctuations, optical transfer, ocular media transmittance, and the aperture, quantum efficiency, and spatial distribution of foveal photoreceptors. The sensitivity of the ideal discriminator was roughly 20-fold greater than that of the human observers, but the shapes of the ideal and human CSFs were quite similar from 5 to 40 c/deg and from 3.4 to 340 cd/m2. The similarity of shapes demonstrates that the high-frequency rolloff of the foveal CSF for gratings with a fixed number of cycles can be explained by the operation of pre-neural factors alone. Previous research has shown that grating summation area is inversely proportional to the square of spatial frequency. Thus, for gratings with fixed spatial extent the high-frequency rolloff can be explained by the pre-neural factors plus variations in grating summation area. These conclusions imply in turn that the neural transfer function is much flatter than previously thought and that private line connections from foveal photoreceptors to higher visual centers are common.
Changes in the activity of selected enzymes during starvation of Physarum polycephalum.

Abstract The levels of glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, lactate dehydrogenase, and cyclic phosphodiesterase activities were examined in growing and starving plasmodia of Physarum polycephalum. The activities of lactate dehydrogenase, 6-phosphogluconate dehydrogenase, and glucose-6-phosphate dehydrogenase decreased whereas that of cyclic phosphodiesterase increased. The change in activity of lactate dehydrogenase was the result of the variation of the activity of a single enzyme quite similar to the lactate dehydrogenases of higher animals.
Silicate Nephrolithiasis After Ingestion of Supplements Containing Silica Dioxide

Silicate calculi are common in some mammals, such as dogs and sheep, but extremely rare in humans. We report a case of silicate calculi in a woman using oral over-the-counter Uncaria tomentosa, Digestive Advantage and FlexProtex supplements. All 3 contained the excipient silica dioxide. Stone analysis showed composition of 100% silicate. The nephrolithiasis promptly abated after discontinuation of the products containing silica, then returned when the patient restarted her supplements. This case emphasizes the importance of stone analysis when obvious causes of nephrolithiasis are unclear and highlights the concerns of using over-the-counter supplements without substantial oversight.
Molecular complexes of tetrahalophthalic anhydrides with aza-aromatics

Abstract Pyridine and its derivatives form charge-transfer (CT) complexes with tetrachloro- and tetrabromo phthalic anhydrides and the spectra are interpreted as π → π* and n → π* transitions.
Anatomy and physiology of coronary blood flow

Regional myocardial blood flow can now be measured noninvasively in units of milliliters blood per minute per gram myocardium. These noninvasive measurements are not confined to a specific imaging modality but are available with MRI, CT, and PET, although, thus far, most investigations of the coronary circulation in humans have employed PET flow measurements. Flow estimates with these different imaging modalities were found in animal experiments to correlate well with invasive flow estimates by the arterial blood sampling-microsphere technique widely considered as the “gold standard” of flow measurements.1-11 In these comparison studies, noninvasively-derived estimates corresponded linearly with invasively-measured myocardial blood flows over a wide flow range, i.e., from as low as 0.3 mL/minute/g to as high as 5-6 mL/minute/g. When tested in the human heart, noninvasive flow estimates correlated well with those obtained through invasively-obtained indices of flow and its changes by well-established alternate measurement approaches.12-16 Development and commercial availability of user-friendly software programs have facilitated the use of these new measurement capabilities so that they are now readily available in the clinical environment for the study of patients with cardiovascular disease. As several investigations have indicated, measurements of myocardial blood flow at rest contain only limited diagnostic information. For example, even in patients with advanced cardiovascular disease such as nonischemic dilated or ischemic cardiomyopathy, hypertrophic cardiomyopathy, or coronary artery disease, resting myocardial blood flows frequently are similar to those in normal individuals.17-19 It is the response of myocardial blood flow to specifically-targeted pharmacological or physiological interventions that can uncover the presence of functional or structural disease-related alterations of the coronary circulation. This then underscores the need for closely examining these targets and how they relate to anatomical and functional determinants of coronary blood flow and, by inference, to myocardial blood flow and their alterations in cardiovascular disease. Local and systemic mechanisms regulate the complex interactions between flow and anatomy in order to meet the heart’s energy needs. A comprehensive description of the coronary circulatory function and its control exceeds the scope of this review so that the interested reader is referred to detailed reviews on this topic.20,21 This review then seeks to describe in broad strokes the major functional and anatomical determinants of coronary blood flow as they pertain to noninvasive measured myocardial blood flows.
A Mathematical Analysis of the Problem of Pointing

This paper contains a mathematical analysis of the problem of automatically pointing a sighting device, mounted on a moving vehicle, at a fixed target. The results apply to situations such as automatic sighting devices for aircraft and helicopters, automatic camera aiming for airborne photography, etc. Basic mathematical relations, which govern all forms of such automatic pointing devices, are derived.
The Wrong Enemy: America in Afghanistan, 2001–2014

New York Times journalist Carlotta Gall covered Afghanistan on the ground from November 2001 to 2011. This hard-earned, grassroots-level perspective lends great credibility to The Wrong Enemy, her ...
The instruction unit of the stretch computer

The Instruction Unit (I unit) was developed as the largest portion and the major control unit of the large-scale, high-performance Stretch computer. This computer is the central processing unit of the Stretch system contracted for development and delivery to the Atomic Energy Commission for their Scientific Laboratories in Los Alamos, New Mexico.
Error bounds for jittered sampling

When timing jitter is present in a sampled-data system, it is important to be able to calculate the error introduced by the jittered sampler. However, a detailed statistical description of the jitter is not usually available to allow the determination of jitter error and the optimum filters. This paper calculates bounds for such error. For single channel sampling, bounds are obtained for such cases where the jitter is independent from sample to sample and where the jitter is correlated. An error bound for a special case of band-pass sampling using two samplers is also derived. In all cases, the signal is assumed to be properly bandlimited, so that, in the absence of jitter, the system is free of error. The final expressions of the error bounds depend, regardless of other jitter statistics, only on the type and the variance of the jitter.
Optimal reproductive strategies for bipedalism

The maintenance of an upright posture poses some significant reproductive problems, not the least of which is sperm retention. Ventral-ventral copulation as well as several other human anatomical and behavioral traits are considered in the context of probablc evolutionary adaptations to bipedalism.
TREATMENT WITH CORTICOSTEROIDS

Oral corticosteroids remain the cornerstone therapy for sarcoidosis. Critical clinical decisions include selecting the patient who should be treated, dose and duration of therapy, and accurate analysis of the anticipated benefits and potential side effects for the individual patient. The treatment of pulmonary and cardiac sarcoidosis is emphasized and the role of inhaled corticosteroids in the treatment of pulmonary sarcoidosis is reviewed.
The Effect of Current-Transformer Residual Magnetism on Balanced-Current or Differential Relays

High-speed current-balance relaying has been subject to occasional false tripping that has not been explained satisfactorily. Field and factory tests now show that this is probably due to differences in residual fluxes in the current-transformer cores. The limiting value of these fluxes can be calculated approximately, and they can be measured with portable instruments connected to the secondary winding. They may cause a deficiency in secondary current, especially during the first half-cycle of fault current, which will cause current-balance or differential-overcurrent relays to operate falsely. This false operation can be avoided by the addition of a short inherent or external time delay with relays having a high dropout, or by the use of special current transformers.
Coordination of cell growth and division by the ubiquitin-proteasome system

The coupling of cellular growth and division is crucial for a cell to make an accurate copy of itself. Regulated protein degradation by the ubiquitin-proteasome system (UPS) plays an important role in the coordination of these two processes. Many ubiquitin ligases, in particular the Skp1-Cullin-F-box (SCF) family and the Anaphase-Promoting Complex (APC), couple growth and division by targeting cell cycle and metabolic regulators for degradation. However, many regulatory proteins are targeted by multiple ubiquitin ligases. As a result, we are only just beginning to understand the complexities of the proteolytic regulatory network that connects cell growth and the cell cycle.
ANALYSIS OF DIESEL PILOT-IGNITED NATURAL GAS LOW-TEMPERATURE COMBUSTION WITH HOT EXHAUST GAS RECIRCULATION

Abstract Earlier efforts demonstrated the low NOx( 40%) benefits of the low temperature, advanced low pilot injection natural gas (ALPING) combustion concept that utilized advanced injection (about 60° BTDC) of small diesel pilots (2–3% on an energy basis) to compression-ignite a premixed natural gas-air mixture. At these injection timings, combustion was accompanied by increased unburned hydrocarbons (HC) (mostly methane) and variations in torque fluctuations. In this article, hot exhaust gas recirculation (EGR) is proposed as a potential strategy to reduce HC emissions and torque fluctuations at low (quarter and half) loads. It is shown that the addition of hot EGR leads to a combination of one or more of the following effects on the intake mixture entering the cylinder: oxygen depletion, increased temperatures due to mixing with exhaust gases, dilution due to introduction of high specific heat species, and active recycling of unburned hydrocarbons to effect reburn in su...
Accounting for other postretirement benefits and pension costs at Ohio Edison

Abstract This is a case on accounting for Other Post Retirement Employee Benefits (OPEB) (SFAS 106, 1990) and Pensions (SFAS 87, 1985). The objective of the case is to enable accounting students to bridge the gap between the two standards and in so doing achieve a better understanding of both. Students can use their knowledge of pension accounting to improve their comprehension of OPEB accounting. This case is suitable for use in Intermediate Accounting, Accounting Policy, and Financial Management courses at the undergraduate and graduate levels.
The Use of DSC to Study the Effects of Solutes on Heterogeneous Ice Nucleation Kinetics in Model Food Emulsions

Abstract Effects of sucrose, D-alanine (amino acid with hydrophobic residue) and potassium nitrate on heterogeneous ice nucleation kinetics were studied with a differential scanning calorimeter (DSC) in a model food emulsion by employing different solute concentrations and ice nucleants: silver iodide (AgI) and Pseudomonas syringae. Heterogeneous nucleation rates were described with a mathematical expression in the same form as suggested by the classical homogeneous nucleation theory. Temperature effects on these rates were an exponential function of a parameter defined in terms of the reduced temperatures. Our results have confirmed that the type of the nucleation template was important in determining the temperature effects of the solutes on the heterogeneous nucleation rates. In the experiments with AgI, values of the model parameters were generally larger then those of the corresponding experiments with P. syringae. Observations with AgI/30 g/100 g sucrose solutions indicated extremely high parameter values which might be caused by the change of the catalytic site of AgI molecules and variation of the emulsion properties by highly concentrated sucrose. With the P. syringae / D-alanine and AgI / D-alanine systems only modest changes were observed in the model parameters with changing D-alanine concentrations. Experimental data with the P. syringae / KNO 3 system suggested that the heterogeneous ice nucleation rates might be affected by denaturation of catalytic site proteins of P. syringae at high salt concentrations.
pIV, a filamentous phage protein that mediates phage export across the bacterial cell envelope, forms a multimer.

Filamentous phage pIV is an outer membrane protein required for phage assembly and secretion. Chemical cross-linking and sedimentation experiments have been used to demonstrate that pIV from fl-infected Escherichia coli exists as a homo-multimer, probably composed of 10 to 12 subunits. pIV secreted from spheroplasts remains soluble and does not form multimers. Synthesis of pIV from distantly related filamentous phages or from a bacterial homolog that participates in a specialized form of extra-cellular protein secretion in the same cell with pIVf1 resulted in the formation of mixed multimers. This suggests that the homologous proteins themselves form homo-multimers. These structures could form gated channels that conduct assembling phage or specific substrate proteins across the outer membrane to the extracellular milieu.
The wraparound process for youth with severe emotional behavioural disorders

The number of youth with serious emotional disorders has increased tremendously; unfortunately, meeting the needs of such children has been a challenge. In an effort to deal with the challenging behaviour exhibited by children and youths, expensive out-of-home placements such as juvenile justice centres and clinical and psychiatric hospitalisation, have been used. Unfortunately, these approaches have not been effective in reducing the rate of challenging and violent behaviours. Therefore, researchers continue seeking evidence-based and cost-effective strategies to use when dealing with children and youths with severe emotional disorders. One of the approaches that have emerged out of this search is the systems of care model, which places emphasis on shifting placement of individuals with severe emotional disturbance from restrictive institutional settings to less restrictive settings. Central to the systems of care model is the wraparound process. The approach involves providing a set of coordinated individualised services and natural supports to the child and family in their natural environment. The purpose of this paper is to provide a literature synthesis on the wraparound process.
Uncertainty Product for a Subensemble of Particles

The Heisenberg uncertainty principle derives from an assumption that all physically permissible location valuesx are included within the ensemble of observations. By contrast, we consider here a case where observation is made over a finite subinterval of the permissiblex values. The resulting uncertainty product forx andkx (wave momentum) is then inconsistent with the Heisenberg principle, as might be expected.
Family patterns of coronary heart disease mortality: the Framingham Longevity Study.

Family patterns for age at death were examined in a 40 year follow-up of 5209 men and women (2900 deceased, 2309 living) in the Framingham Study and their parents. Age at death of both mothers and fathers was significantly older for surviving offspring when compared to decreased offspring (p < 0.0001). When longevity was assessed according to cause of death in the offspring, parental age at death was a significant predictor of death by coronary heart disease (CHD), but not for stroke or cancer. Multiple regression analysis for offspring with sudden CHD death revealed that mother's age at death was a significant predictor of age at sudden CHD death (p < 0.0003) whereas father's age at death was a significant predictor of age at death in non-sudden CHD death (p < 0.004). Life table analysis showed longest survival rates associated with both parents surviving to age 75 or older followed by mother only surviving to age 75 or older, then father only, and shortest survival with neither parent surviving to age 75. Longevity appears to be more strongly associated with maternal death age than parental death age. Proportional hazards analysis of risk factors associated with CHD revealed that systolic blood pressure, sex of the individual, and cigarette smoking were the most significant predictors of death age. These findings suggest that familial similarities for death age may be mediated primarily through shared CHD risk factors within families, either genetic or non-genetic.
Linkage theory for algebras with pure resolutions

Abstract Let S be a graded Cohen-Macaulay quotient R I of a polynomial ring R = k [ X 1 ,…, X n ] over an infinite field k . If S is in the linkage class of a complete intersection then its Koszul homology and twisted conormal module are Cohen-Macaulay. By passing to zero- and one-dimensional specializations of S , one can convert these properties into numerical test conditions for a graded algebra to be in the linkage class of a complete intersection. We prove that if S is generically a complete intersection and the minimal free solution of S is pure and almost linear, then S is not in the linkage class of a complete intersection (apart from a few obvious exceptions). For algebras of small codimension the results are stronger: if S has codimension three and has a pure resolution, then S is in the linkage class of a complete intersection if and only if S is Gorenstein; if S is a codimension four Gorenstein algebra with a pure resolution then S is in the linkage class of a complete intersection if and only if S is a complete intersection.
The geometrical relationship between the human esophagus and left ventricle: Implications for three-dimensional ultrasonic scanning

Abstract To establish design parameters for a transesophageal ultrasonic probe to image the left ventricle (LV) in three dimensions, the geometrical relationship between the esophagus and the heart was studied in computed tomographic sections of ten humans. Points describing the esophageal centerpoint and the left-ventricular endocardium were digitized. Algorithms were developed to determine from any esophageal viewpoint the ranges of motion required to cover the LV with four modes of scanning; transverse oblique, longitudinal oblique, rotary and linear. Longitudinal oblique scanning was the only single-degree-of-freedom method that allowed complete imaging of the LV in all patients. However, for both conventional and three-dimensional LV imaging, the most promising probe design appears to be a rotary scanning probe with an added degree of freedom to tilt the axis of rotation ± 29° away from an axis perpendicular to the local esophageal axis.
Injury risks in children of California migrant Hispanic farm worker families

BACKGROUND: Few data are available addressing occupational and other injury risks among children of migrant Hispanic farm workers. METHODS: We conducted the U.C. Davis Farm Worker Injury Study (UCD-FWIS), a longitudinal follow-up study of injury among migrant Hispanic farm worker families living in six Northern California Migrant Housing Centers (MHCs). Nine hundred forty-one children (age
Risk factors for anabolic-androgenic steroid use in men

The illicit use of anabolic steroids to enhance athletic performance and physical appearance can cause numerous psychiatric and other adverse effects. In order to prevent steroid use and its negative consequences, knowledge of risk factors is needed. We conducted an anonymous survey of 404 male weight lifters from community gymnasiums who completed a 20-min, self-administered questionnaire. The sample for this study included all 35 men who were thinking about using steroids ("high-risk" nonusers), 50 randomly selected nonusers who were not thinking about using steroids ("low-risk" nonusers) and all 49 steroid users. The three groups differed in age, training characteristics, other performance-enhancers tried, body image, acquaintance with steroid users, and perception of negative consequences. When groups were compared along a continuum from low risk to high risk and from high risk to actual use, we found increasing amounts of competitive bodybuilding, performance-enhancers tried, and steroid-using acquaintances. Groups did not differ in their use of addictive substances. Nearly three-fourths of the high-risk group felt "not big enough," compared to 21% of the low-risk group and 38% of the steroid users (p < .001). These data suggest that steroids do work to increase satisfaction with body size, and that dissatisfaction with body size may contribute to the risk of using steroids.
Devastatingly Human: An Analysis of Registered Nurses’ Medication Error Accounts

Despite many safeguards, nurses make the majority of medication administration errors. The purpose of our research was to investigate the perceived causes for such errors and to better understand how nurses deal with them. We performed an interpretive analysis of 158 accounts by nurses who made self-identified medication errors. We found common themes among these accounts. First, although nurses admitted responsibility for errors, they simultaneously identified a variety of external contributing factors. Second, nurses' accounts were often framed in terms of "being new," with the underlying background expectancy of inexperience. Third, emotionally devastating visceral responses to errors were common and often incongruent with error severity. Fourth, nurses had to deal with fear. Fifth, nurses voiced frustrations with technologies and regulations. Sixth, embedded within many of the accounts was a "lessons learned" theme, through which nurses developed "personal rules" as a result of an error. We conclude with suggestions for additional research.
Discrimination reversal learning in capuchin monkeys (Cebus apella)

Learning styles in capuchin monkeys were assessed with a computerized reversal-learning task called the mediational paradigm. First, monkeys were trained to respond with 90% accuracy on a two-choice discrimination (A+B-−). Then the authors examined differences in performance on three different types of reversal trials (A-−B+, A-−C+, B+C-−), each of which offered differing predictions for performance, depending on whether the monkeys were using associative cues or rule-based strategies. Performance indicated that the monkeys mainly learned to avoid the B stimulus during training, as the A-−C+ condition produced the best performance levels. Therefore, negative stimuli showed greater control over responding after reversal and reflected a more associative rather than rule-based form of learning.
Laser-enhanced ionization with avalanche amplification: detection of cesium at fg/mL levels.

The avalanche amplification of the laser-enhanced ionization signal of Cs atoms in a flame has been studied. Ionization of Cs atoms, enhanced by two-step excitation, was detected in hydrogen and propane flames. By employing the effect of avalanche amplification of electrons, high signal-to-noise ratio (~104) was obtained for a 100 ppt Cs solution. The extrapolated limit of detection was 30 fg/mL (ppq).
The Role of Bottom Vortex Stretching on the Path of the North Atlantic Western Boundary Current and on the Northern Recirculation Gyre

Abstract The mechanisms affecting the path of the depth-integrated North Atlantic western boundary current and the formation of the northern recirculation gyre are investigated using a hierarchy of models, namely, a robust diagnostic model, a prognostic model using a global 1° ocean general circulation model coupled to a two-dimensional atmospheric energy balance model with a hydrological cycle, a simple numerical barotropic model, and an analytic model. The results herein suggest that the path of this boundary current and the formation of the northern recirculation gyre are sensitive to both the magnitude of lateral viscosity and the strength of the deep western boundary current (DWBC). In particular, it is shown that bottom vortex stretching induced by a downslope DWBC near the south of the Grand Banks leads to the formation of a cyclonic northern recirculation gyre and keeps the path of the depth-integrated western boundary current downstream of Cape Hatteras separated from the North American coast. Bo...
A framework for understanding Latent Semantic Indexing (LSI) performance

In this paper we present a theoretical model for understanding the performance of Latent Semantic Indexing (LSI) search and retrieval application. Many models for understanding LSI have been proposed. Ours is the first to study the values produced by LSI in the term by dimension vectors. The framework presented here is based on term co-occurrence data. We show a strong correlation between second-order term co-occurrence and the values produced by the Singular Value Decomposition (SVD) algorithm that forms the foundation for LSI. We also present a mathematical proof that the SVD algorithm encapsulates term co-occurrence information.
Chloroviruses Encode a Bifunctional dCMP-dCTP Deaminase That Produces Two Key Intermediates in dTTP Formation

The chlorovirus PBCV-1, like many large double-stranded DNA-containing viruses, contains several genes that encode putative proteins involved in nucleotide biosynthesis. This report describes the characterization of the PBCV-1 dCMP deaminase, which produces dUMP, a key intermediate in the synthesis of dTTP. As predicted, the recombinant protein has dCMP deaminase activity that is activated by dCTP and inhibited by dTTP. Unexpectedly, however, the viral enzyme also has dCTP deaminase activity, producing dUTP. Typically, these two reactions are catalyzed by proteins in separate enzyme classes; to our knowledge, this is the first example of a protein having both deaminase activities. Kinetic experiments established that (i) the PBCV-1 enzyme has a higher affinity for dCTP than for dCMP, (ii) dCTP serves as a positive heterotropic effector for the dCMP deaminase activity and a positive homotropic effector for the dCTP deaminase activity, and (iii) the enzymatic efficiency of the dCMP deaminase activity is about four times higher than that of the dCTP deaminase activity. Inhibitor studies suggest that the same active site is involved in both dCMP and dCTP deaminations. The discovery that the PBCV-1 dCMP deaminase has two activities, together with a previous report that the virus also encodes a functional dUTP triphosphatase (Y. Zhang, H. Moriyama, K. Homma, and J. L. Van Etten, J. Virol. 79:9945-9953, 2005), means that PBCV-1 is the first virus to encode enzymes involved in all three known pathways to form dUMP.
Fractionation: a panoramic view.

Some of the earliest successfully irradiated carcinomas of the skin and lower lip were accompanied by excellent esthetic results. These results were due to the long fractionation imposed on the pioneers by the low output of gas tubes. After the First World War, improvements on generators and the hot cathode tube, permitted the use of higher kilovoltage and milliamperage with consequent greater penetration and output. Roentgentherapy of internal tumors became possible with what was called deep therapy (radiotherapie profonde, tiefentherapie). With the means at hand, various modalities of approach gradually developed ( 14).
New tools, new insights: Kohlberg’s moral judgement stages revisited

In this paper, four sets of data, collected by four different research teams over a period of 30 years are examined. Common item equating, which yielded correlations from .94 to .97 across datasets...
Poincaré inequalities and Sobolev spaces

Our understanding of the interplay between Poincare inequalities, Sobolev inequalities and the geometry of the underlying space has changed considerably in recent years. These changes have simultaneously provided new insights into the classical theory and allowed much of that theory to be extended to a wide variety of different settings. This paper reviews some of these new results and techniques and concludes with an example on the preservation of Sobolev spaces by the maximal function. [Proceedings of the 6th International Conference on Harmonic Analysis and Partial Differential Equations, El Escorial (Madrid), 2002].
Comparative Selenium Retention by Chicks Fed Sodium Selenite, Selenomethionine, Fish Meal and Fish Solubles

Abstract Two experiments were conducted to assay the retention of Se from varying levels of fish meal and solubles and in the second experiment to compare also the retention with that from comparable levels of sodium selenite and selenomethionine. The basal diet contained crystalline amino acid diets and high levels of α-tocopherol acetate (200 and 300 p.p.m.). In the first experiment day-old chicks were found to contain 11 μg. Se whereas chicks fed the basal diet for 21 days without any Se supplements contained 37% less. In the second experiment the day-old chicks started with a body reserve of 13 μg. Se, of which 35% was lost when fed the basal diet for 18 days. A Se balance in the chick was maintained by a dietary level of 0.05 p.p.m. from any of the sources studied. This quantity of Se was supplied by a dietary level of 2.5% fish meal or solubles. A level of 5% fish meal or solubles in the diet supplied about 0.1 p.p.m. total Se of which 16–29% was retained in the chick body in the first experiment and 15% in the second experiment. The retention value obtained in the second experiment, by supplying 0.1 p.p.m. Se from sodium selenite, was 35% and, therefore, in comparison the same levels of Se in fish meal or solubles was about 43% as effective as the standard. Compared to selenomethionine at the same level of Se, the fishery products were 31% as effective.
Regional Visibility Statistics in the United States: Natural and Transboundary Pollution Influences, and Implications for the Regional Haze Rule

The Regional Haze Rule of the US Environmental Protection Agency mandates reduction in US anthropogenic emissions to achieve linear improvement of visibility in wilderness areas over the 2004–18 period toward an endpoint of natural visibility conditions by 2064. Linear improvement is to apply to the mean visibility degradation on the statistically 20% worst days, measured as a Haze Index in units of deciviews (log of aerosol extinction). We use a global chemical transport model (GEOS-Chem) with 11 � 11 horizontal resolution to simulate present-day visibility statistics in the USA, compare them to observations from the Interagency Monitoring of Protected Visual Environments (IMPROVE) surface network, and provide natural and background visibility statistics for application of the Regional Haze Rule. Background is defined by suppression of US anthropogenic emissions but allowance for present-day foreign emissions and associated import of pollution. Our model is highly successful at reproducing the observed variability of visibility statistics for present-day conditions, including the low tail of the frequency distribution that is most representative of natural or background conditions. We find considerable spatial and temporal variability in natural visibility over the USA, especially due to fires in the west. A major uncertainty in estimating natural visibility is the sensitivity of biogenic organic aerosol formation to the availability of preexisting anthropogenic aerosol. Background visibility is more variable than natural visibility and the 20% worst days show large contributions from Canadian and Mexican pollution. Asian pollution, while degrading mean background visibility, is relatively less important on the worst days. Recognizing the influence of uncontrollable transboundary pollution in the Regional Haze Rule would substantially decrease the schedule of emission reductions required in the 2004–18 implementation phase. Meaningful application of the Rule in the future will require projections of future trends in foreign anthropogenic emissions, wildfire frequency, and climate variables. r 2006 Elsevier Ltd. All rights reserved.
Magnetic orientation and navigation in marine turtles, lobsters, and molluscs: concepts and conundrums.

SYNOPSIS. The Earth’s magnetic field provides a pervasive source of directional information used by phylogenetically diverse marine animals. Behavioral experiments with sea turtles, spiny lobsters, and sea slugs have revealed that all have a magnetic compass sense, despite vast differences in the environment each inhabits and the spatial scale over which each moves. For two of these animals, the Earth’s field also serves as a source of positional information. Hatchling loggerhead sea turtles from Florida responded to the magnetic fields found in three widely separated regions of the Atlantic Ocean by swimming in directions that would, in each case, facilitate movement along the migratory route. Thus, for young loggerheads, regional magnetic fields function as navigational markers and elicit changes in swimming direction at crucial geographic boundaries. Older turtles, as well as spiny lobsters, apparently acquire a ‘‘magnetic map’’ that enables them to use magnetic topography to determine their position relative to specific goals. Relatively little is known about the neural mechanisms that underlie magnetic orientation and navigation. A promising model system is the marine mollusc Tritonia diomedea, which possesses both a magnetic compass and a relatively simple nervous system. Six neurons in the brain of T. diomedea have been identified that respond to changes in magnetic fields. At least some of these appear to be ciliary motor neurons that generate or modulate the final behavioral output of the orientation circuitry. These findings represent an encouraging step toward a holistic understanding of the cells and circuitry that underlie magnetic orientation behavior in one model organism.