cssi/SciSciGPT-SciSciNet huggingface dataset:
Fluorochemical perfusates for renal preservation.

Abstract We have evaluated the use of dispersed fluorochemicals in cryoprecipitated plasma as a perfusage for renal preservation. FC-43(47) has been shown to be a superior perfusate to FX-80 despite its lower oxygen binding capacity. Significant improvement in survival of transplanted kidneys following 24 hr hypothermic perfusion was experienced with the FC-43(47). When comparing the FC-43(47) dispersion with plasma, no significant differences were found in the perfusion characteristics of the kidney while on the perfusion apparatus aside from the creatinine clearances which were significantly higher with the fluorochemical perfusate. One hundred percent of the kidneys perfused with the FC-43(47) perfusate survived with normal creatinines at the end of 30 days compared to only 27% perfused with FX-80 and 62% perfused only with plasma. The maximum creatinine that developed with FC-43(47) was not significantly different from the value obtained with the plasma perfusates. While these experiments do not clearly establish fluorochemical perfusates as superior to plasma, they indicate that in longer term perfusions of 48 and 72 hr a significant difference may be observed.
Directional coronary atherectomy vs. rotational atherectomy for the treatment of in-stent restenosis of native coronary arteries.

Management of in-stent restenosis has become a significant challenge in interventional cardiology. Since the mechanism of in-stent restenosis is predominantly intimal hyperplasia, debulking techniques have been used to treat this condition. This study is a nonrandomized comparison of the immediate and long-term results of directional coronary atherectomy (DCA; n = 58) vs. high-speed rotational atherectomy (ROTA; n = 61) for the treatment of in-stent restenosis of native coronary arteries. There were no in-hospital deaths, Q-wave myocardial infarctions, or emergency coronary artery bypass surgery in either group. DCA resulted in a larger postprocedural minimal luminal diameter of (2.57 ± 0.51 vs. 2.14 ± 0.37 mm; P < 0.0001) and a larger acute gain (1.83 ± 0.52 vs. 1.42 ± 0.48 mm; P < 0.0001). Furthermore, 12-month clinically indicated target lesion revascularization (39% vs. 21%; P = 0.02) and long-term follow-up MACE (44% vs. 28%; P = 0.03) was greater in the ROTA group. The present study suggests that DCA appears to be superior to ROTA for the treatment of in-stent restenosis of native coronary arteries. Compared to ROTA, the debulking effect of DCA leads to a larger postprocedure minimal luminal diameter, and a lower incidence of subsequent target lesion revascularization and MACE. Cathet Cardiovasc Intervent 2003;58:155–161. © 2003 Wiley-Liss, Inc.
Femoral hernia in infancy and childhood.

Abstract Ten years of experience with femoral hernia in children is reviewed. The following principles emerge from examples noted. Although femoral hernia is rare in childhood, it should be considered, especially in recurrent inguinal hernias or where the operative findings do not match the preoperative diagnosis. Nothing substitutes for a careful preoperative examination. A bulge inferior to the inguinal canal and Poupart's ligament suggests a femoral hernia. Repair of both direct and femoral hernias is best accomplished using Cooper's ligament. Poupart's ligament repair should never be used, as this weakens the femoral canal and may lead to an iatrogenic femoral hernia.
Blood Fraction Effects on the Antibotulinal Efficacy of Nitrite in Model Beef Sausages

Toxin production by Clostridium botulinum was studied in a model cured beef sausage containing 0–5% added dried bovine blood fractions. Controls which contained nitrite but without blood fractions, were toxic by bioassay in 3 wk at 27°C. Controls without nitrite or blood fractions were toxic at 1 wk, while model sausages supplemented with hemoglobin, red cells, or whole blood were toxic in 1–3 wk. Plasma yielded no detectable toxin for 4 to > 10 wk depending upon addition level. Sausages showing delayed toxigenesis had pH values lower than those which developed toxin earlier. These results demonstrated that use of blood fractions that increased iron levels in beef above 30 μ.g/g interfered with the antibotulinal efficacy of sodium nitrite.
Planar IGRT dose reduction: A practical approach.

Abstract Purpose To retrospectively estimate the cumulative absorbed dose (at the skin) from kilovoltage planar x-rays received by 90 patients treated on a Varian iX and to determine if that dose could be reduced without sacrificing image quality. Methods and materials To estimate surface dose, measurements were obtained using the “in-air” method by varying the source-to-detector distance from 80 to 100 cm in steps of 5 cm. Energy was varied from 70 to 120 kVp. Using these data, a global equation was developed to estimate the cumulative skin dose by applying the imaging settings (kVp, mAs), patient-specific source-to-skin distance, and total number of images. To reduce the imaging dose, anterior and lateral images of RANDO phantoms were obtained using the same kVp; however, the mAs settings were systematically reduced. Contrast-to-noise ratios (CNRs) were calculated for both the standard phantom images and reduced mAs images. The mAs values were chosen to minimize skin dose while maintaining a similar CNR. Last, daily kV anterior and lateral images were obtained using these reduced mAs settings for 7 patients currently being treated with image guided radiation therapy. CNR was determined and compared with the values obtained on images taken 1 day before this change. Results Average cumulative kV imaging dose was as large as 162.2 cGy for pelvic cases with standard kVp, mAs. Other doses varied by site and technique. By lowering mAs, this dose could be reduced by 49% with only a 0.9% decrease in CNR. For the 7 patients currently being treated with image guided radiation therapy, CNR values were not statistically different ( P = .79), whereas the skin dose was reduced by an average of approximately 50%. Conclusions kV planar imaging dose reduction should be considered, given the large cumulative skin dose for certain disease sites. When mAs are reduced, planar dose reduction is clinically feasible without sacrificing image quality.
A comparative analysis of results and morbidity in type I diabetics undergoing preemptive versus postdialysis combined pancreas-kidney transplantation.

Although combined pancreas-kidney transplantation (PKT) has become a valid treatment option for selected type I diabetics, the timing of PKT relative to the degree of nephropathy remains controversial. We analyzed results and morbidity in 30 type I diabetics undergoing PKT after starting dialysis (PKT;D) versus 31 type I diabetics undergoing PKT prior to dialysis (PKT:ND). The two groups were similar with the respect to age, duration and severity of diabetes, gender, race, preservation time, retransplants, sensitization, HLA-matching, and CMV status
The association between psychosis and violent crime: a study of offenders evaluated at a court psychiatric clinic.

Summary Examination of 2100 psychiatric evaluations conducted by a court psychiatric clinic to determine competency or for a presentence evaluation indicated no association between a diagnosis of psychosis and commission of a crime of violence. However, offenders referred for a pretrial competency examination were more likely to have committed a crime of violence than were defendants seen for a presentence evaluation. The implications of these results are discussed.
Use of a Victoreen 500 electrometer to determine ionization chamber collection efficiencies

An investigation has been made of the Victoreen 500 electrometer’s capability to predict saturation corrections for ionization chambermeasurements. This electrometer has been provided with a switch that reduces the polarizing voltage on the chamber to 40% of its normal value. It can be demonstrated theoretically that ion chambermeasurements at two separate voltages should be sufficient to determine the saturation correction, for both pulsed beams and continuous radiation. Tests were made with the Victoreen 500 which indicated that this is the case. Saturation corrections of up to 10% have been demonstrated for both pulsed and continuous beams and these can be predicted using the Victoreen 500 electrometer to within 1%. Key words: ionization chambers, collection efficiency, pulsed beams, electrometers,dosimetry
A compact finite difference method on staggered grid for Navier-Stokes flows

Compact finite difference methods feature high-order accuracy with smaller stencils and easier application of boundary conditions, and have been employed as an alternative to spectral methods in direct numerical simulation and large eddy simulation of turbulence. The underpinning idea of the method is to cancel lower-order errors by treating spatial Taylor expansions implicitly. Recently, some attention has been paid to conservative compact finite volume methods on staggered grid, but there is a concern about the order of accuracy after replacing cell surface integrals by average values calculated at centres of cell surfaces. Here we introduce a high-order compact finite difference method on staggered grid, without taking integration by parts. The method is implemented and assessed for an incompressible shear-driven cavity flow at Re = 103, a temporally periodic flow at Re = 104, and a spatially periodic flow at Re = 104. The results demonstrate the success of the method. Copyright © 2006 John Wiley & Sons, Ltd.
The ongoing development of mathematics teachers’ knowledge and practice: considering possibilities, complexities, and measures of teacher learning

The professional learning of mathematics teachers is an area of central concern in the field of mathematics teacher education. Researchers in mathematics teacher education strive to understand changes in teachers’ knowledge and practice over time and in different contexts. Much of the research in our field aims to document, understand, and measure the impact of opportunities for teachers to learn through diverse experiences ranging from coursework to practice-based professional learning communities. The three articles in this issue of the Journal of Mathematics Teacher Education (JMTE) contribute to this body of scholarship by reporting about important questions and issues emerging from professional development activities in three countries. Each article builds on previous work in mathematics teacher education in significant ways and, through the insights each provides, opens the door for further research about teacher learning. Two of the articles in this issue provide analytic accounts of the possibilities and complexities of teachers’ joint observation and discussion of practice. Alf Coles’s reflection on a video-based discussion group and Takeshi Miyakawa and Carl Winslow’s account of an ‘‘open lesson’’ reveal the potential for teachers to learn together through the development of shared knowledge about mathematics teaching. This potential is striking when we consider that much of teachers’ daily work occurs in the privacy of individual classrooms. It was beyond the scope of either of these studies to examine or measure changes in teachers’ knowledge or practice; instead, the researchers focused on exploring what might be the educative aspects of teachers’ practice-based discussions. Yet, it is natural to wonder about the impact of such professional development activities on the knowledge and practices of participating teachers. Yasemin Copur-Gencturk and Sarah Lubienski shift our focus to the measurement of the impact of coursework on teachers’ mathematical knowledge. Through their examination of the types of changes that two commonly used instruments detected in teachers’ mathematical knowledge during graduate courses, these authors provide some evidence for theoretical distinctions among certain components of teachers’ mathematical knowledge.
Clarity versus complexity: Land-use modeling as a practical tool for decision-makers

The last decade has seen a remarkable increase in the number of modeling tools available to examine future land-use and land-cover (LULC) change. Integrated modeling frameworks, agent-based models, cellular automata approaches, and other modeling techniques have substantially improved the representation of complex LULC systems, with each method using a different strategy to address complexity. However, despite the development of new and better modeling tools, the use of these tools is limited for actual planning, decision-making, or policy-making purposes. LULC modelers have become very adept at creating tools for modeling LULC change, but complicated models and lack of transparency limit their utility for decision-makers. The complicated nature of many LULC models also makes it impractical or even impossible to perform a rigorous analysis of modeling uncertainty. This paper provides a review of land-cover modeling approaches and the issues causes by the complicated nature of models, and provides suggestions to facilitate the increased use of LULC models by decision-makers and other stakeholders. The utility of LULC models themselves can be improved by 1) providing model code and documentation, 2) through the use of scenario frameworks to frame overall uncertainties, 3) improving methods for generalizing key LULC processes most important to stakeholders, and 4) adopting more rigorous standards for validating models and quantifying uncertainty. Communication with decision-makers and other stakeholders can be improved by increasing stakeholder participation in all stages of the modeling process, increasing the transparency of model structure and uncertainties, and developing user-friendly decision-support systems to bridge the link between LULC science and policy. By considering these options, LULC science will be better positioned to support decision-makers and increase real-world application of LULC modeling results.
Bimorph deformable mirror: an appropriate wavefront corrector for retinal imaging?

The purpose of this study was to evaluate the performance of a bimorph deformable mirror from AOptix, inserted into an adaptive optics system designed for in-vivo retinal imaging at high resolution. We wanted to determine its suitability as a wavefront corrector for vision science and ophthalmological instrumentation. We presented results obtained in a closed-loop system, and compared them with previous open-loop performance measurements. Our goal was to obtain precise wavefront reconstruction with rapid convergence of the control algorithm. The quality of the reconstruction was expressed in terms of root-mean-squared wavefront residual error (RMS), and number of frames required to perform compensation. Our instrument used a Hartmann-Shack sensor for the wavefront measurements. We also determined the precision and ability of the deformable mirror to compensate the most common types of aberrations present in the human eye (defocus, cylinder, astigmatism and coma), and the quality of its correction, in terms of maximum amplitude of the corrected wavefront. In addition to wavefront correction, we had also used the closed-loop system to generate an arbitrary aberration pattern by entering the desired Hartmann-Shack centroid locations as input to the AO controller. These centroid locations were computed in Matlab for a user-defined aberration pattern, allowing us to test the ability of the DM to generate and compensate for various aberrations. We conclude that this device, in combination with another DM based on Micro-Electro Mechanical Systems (MEMS) technology, may provide better compensation of the higher-order ocular wavefront aberrations of the human eye
Levels and Characteristics of Physical Activity among a College Student Cohort.

Abstract The purpose of this study was to assess physical activity levels and the relationships between activity and personal characteristics among a cohort of college students and to determine personal characteristics that predict activity. A sample of 1,700 undergraduates was mailed a survey that requested demographic information and assessed health behaviors including self-reported physical activity. Of the 1,575 successfully mailed, a total of 903 completed questionnaires were received—a response rate of 57.3%. Nearly half of the respondents indicated they “exercised or participated in sports activities for at least 20 minutes that made you sweat or breathe hard” on three or more of the preceding 7 days (VIG). Nearly three-fifths reported they “walked or biked for at least 30 minutes at a time” on 3 or more of the preceding 7 days (MOD). Those reporting VIG were more likely to be younger Caucasian males. Those reporting MOD were more likely to be younger Caucasian females. Gender, race, being an inter...
Effects of chemical stimulation of the hypothalamus upon gastric secretion

Abstract Male rats with a permanently implanted cannula in the feeding area of the hypothalamus were tested for a reliable eating response to adrenergic stimulation of the LHA and a reliable drinking response to cholinergic stimulation. The effects of intrahypothalamic administration of 40 mM norepinephrine and 2, 4 mM carbachol upon the acid output of the constantly perfused stomach of curarized rats were investigated. After the injection of norepinephrine a twofold increase in the acid output was observed and a decrease of an equal amount occurred after an injection of carbachol. The results are consistent with the hypothesis that some regions of the hypothalamus can subserve a sympathic and parasympathic function depending upon how they are chemically stimulated.
GEOHYDROLOGIC ANALOGIES BETWEEN THE JORDAN VALLEYS OF UTAH AND THE HOLY LAND

Abstract The biblical Jordan River Valley, which extends from Lake Tiberias (the Sea of Galilee) to the Dead Sea, is decidedly similar to the Jordan River Valley of Utah, which joins Lake Utah and Great Salt Lake. Both Jordan Rivers drain relatively large fresh-water lakes and also are major sources of discharge into large salty lakes that have no outlets to the ocean. The two Jordan River valleys and the highlands and mountains that surround them, have many physiographic, geologic, and hydrologic similarities as well as some noteworthy differences. For example, an hypothesis for the formation of the Dead Sea-Jordan Valley rift is that the east Jordan block slid northward with respect to the west Jordan block. The amount of displacement is estimated to be about 65 miles and took place partly in Miocene and possible Pliocene and partly in Pleistocene time. Tectonc activity has also been a major factor in the formation of the Jordan valley of Utah, but the movement here probably was along large normal fault...
Flexural strength of tubular flange girders

Abstract A tubular flange girder is an I-shaped steel girder with either rectangular or round tubes as flanges. A tubular flange girder has a much larger torsional stiffness than a conventional I-shaped plate girder of similar weight, which results in a much larger lateral–torsional buckling strength. Finite element (FE) models of tubular flange girders with hollow tubes (HTFGs) are developed in this paper, considering material inelasticity, instability, initial geometric imperfections, and residual stresses. A parametric study is performed using the FE models to study the effects of stiffeners, geometric imperfections, residual stresses, cross section dimensions, and bending moment distribution on the lateral–torsional buckling flexural strength of HTFGs. These analytical results are used to evaluate formulas for determining the flexural strength of HTFGs.
Growth Performance of Largemouth Bass Fed Fish Meal Derived from Asian Carp

AbstractFeeds for carnivorous fish like Largemouth Bass Micropterus salmoides are commonly based on marine-origin fish meal, but this ingredient is costly. Fish meal derived from undesirable species, such as invasive Asian carp Hypophthalmichthys spp., is a promising alternative source of protein for carnivorous fish, but information regarding its biological value as a feed ingredient is limited. Accordingly, we evaluated the growth performance of juvenile Largemouth Bass (initial weight, 11.6±0.2 g [mean±SE]) reared for 8 weeks on practical diets (∼14.5% lipid, ∼42% digestible protein) containing different levels of menhaden fish meal (MFM), Asian carp meal (CFM), or a 50:50 blend of these ingredients such that 40% (40 MFM, 40 CFM) or 60% (60 MFM, 60 CFM, 60 Blend) of the estimated digestible protein content was derived from fish meal. Weight gain (329–388%), feed conversion ratio (0.78–0.97), and specific growth rate (2.65–2.88% body weight/d) were generally consistent among treatments. Although our res...
Production Characteristics of PanSize Channel Catfish in Cages and Open Ponds1

Production characteristics of pan-size (approximately 227 g) channel catfish (Ictalurus puncturus) were determined in cages and open ponds stocked with fingerlings to densities of 20,000 and 12,500 fish/ha. After 145 days, mean fish weight in all treatments exceeded 227 g. Mean survival was similar in all treatments. Food conversion ratios were significantly better in ponds than in cages but density did not affect the ratios. Neither density nor production system affected production (as measured by total weight produced) when initial density differences were considered (analysis of covariance). Variability in total length at harvest was similar between production systems; however, low density treatments were less variable than high density treatments. Results of this study indicate that pan-size channel catfish can be cultured efficiently at stocking densities well above the 12,500 fish/ha (5,000 fishlacre) generally used when culturing fish to larger sizes.
Preparation of permethyloctadecasilane and permethyltetracosasilane

Abstract The synthesis and characterization of Me(SiMe2)18Me and Me(SiMe2)24Me, reported herein, significantly extends the series of known linear permethylpolysilanes.
Depression of whole-brain oxygen extraction fraction is associated with poor outcome in pediatric traumatic brain injury

Depression of whole-brain oxygen extraction fraction is associated with poor outcome in pediatric traumatic brain injury
Large double-stranded RNA molecules in Phaseolus vulgaris L. are not associated with cytoplasmic male sterility

Two large double-stranded RNA molecules, 15 and 16 kilobases, were detected in cytoplasmic male sterile (CMS) Phaseolus vulgaris by agarose gel electrophoresis. A number of smaller RNA molecules were observed in ‘Sprite’, a maintainer line, and recurrent backcrossing of CMS P. vulgarisx‘Sprite’ resulted in a combined electrophoretic pattern of the two large and numerous small RNA molecules. The large RNA molecules were seed and pollen-transmissible, but were not transmitted by grafting. The RNAs were present in revertant and restored lines derived from CMS-Sprite and therefore were not associated with the cytoplasmic male sterile trait.
Activation of microsomal guanylate cyclase by a cytotoxic polypeptide: Melittin

Abstract Melittin, a 26 amino acid polypeptide, activated membrane-associated guanylate cyclase in a manner suggesting that membrane phospholipids play an important role in regulating the enzyme activity. Melittin was unique in that it activated only the particulate activity in a dose-dependent manner in the concentration range 15 to 200 μg/ml, and, unlike other known activators, solubilization of enzyme did not occur. The effects of melittin on guanylate cyclase showed a lag of two minutes and were not blocked by inhibitors of prostaglandin synthetase or phospholipase suggesting that the effect was not mediated by prostaglandin endoperoxides or phospholipase products but may be due to the ability of melittin to alter membrane lipid properties.
Overcoming Polarization Aberrations In Microscopy

A long-standing problem in polarized light microscopy has been the inability, due to polarization aberrations, to achieve simultaneously high spatial resolution and high contrast. The rotation of the plane of polarization at oblique interfaces between crossed polars causes the pupil function to resemble a dark cross rather than being uniformly dark. Likewise, the point spread function has the visual appearance of a four-leaf clover rather than the ideal Airy disk, and is also space-variant. Images formed with these systems are severely degraded. In this paper the theory of polarization aberrations is applied to the analysis of three solutions to this problem: Reducing the system aperture to block troublesome high-aperture rays; the AVEC-POL method, in which high bias compensation introduces counterbalancing aberrations; and the polarization rectifier, an optical element designed to introduce equal and opposite rotations of the electric vector.
Brain scanning in the pediatric age group.

SUMMARY Between January 1964 and January 1967, 130 children had brain scans with Technetium-99m pertechnetate at the North Carolina Baptist Hospital. There were 38 positive scans among this group; 25 children were proved to have intracranial neoplasms and the brain scan localised 20 (80 per cent) of these. Of the 14 tumors located in the posterior fossa, 13 were visualised for an accuracy of 93 per cent. Only 7 of 11 supratentorial tumors were demonstrated (63 per cent accuracy). Other lesions, such as A-V malformations, cerebral infarction, brain abscesses and meningitis gave positive scans. RESUME Gamma-encephalographie chez l' enfant Entre les mois de Janvier 1964 et Janvier 1967, 130 enfants ont subi une gammaencephalographie avec ‘Ion pertechnetate (technetium-99)’a l'hopital baptiste de la Caroline du Nord. 38 resultats positifs furent notes dans ce groupe; parmi eux on a pu prouver l'existence, chez 25 enfants, de tumeurs intracrâniennes et une localisation par la gamma-encephalographie fut obtenue dans 20 cas (80 pour cent). Sur 14 tumeurs de la fosse posterieure, 13 furent mises en evidence par la gamma-encephalographie avec une precision de 93 pour cent. Seulement 7 sur 11 tumeurs supra-tentorielles furent mises en evidence par les memes techniques (63 pour cent de resultats positifs). D'outres lesions, telles que des malformations arterioveineuses, des ramolissements cerebraux, des abces du cerveau et des lesions meningitiques donnerent des resultats positifs. ZUSAMMENFASSUNG Hirn-Szintigraphie bei Kindern Von Januar 1967 bis Januar 1967 wurde an 130 Kindern eine Hirn-Szintigraphie mit Technetium-99m-pertechnetat vorgenommen im North Carolina Baptist Hospital. In dieser Gruppe fanden sich 38 positive Szintigramme. Bei 25 Kindern wurde ein intracranieller Tumor festgestellt, der durch die Hirn-Szintigraphie in 20 Fallen (80 %) genau lokalisiert wurde. Von 14 Tumoren der hinteren Schadelgrube wurden 13 erkannt, welches eine Treffsicherheit von 93 % ausmacht. Dagegen wurden nur 7 von 11 supratentoriellen Tumoren erkannt (Treffsicherheit: 63%). Andere Veranderungen wie arterievenose Miβbildungen, cerebrale Infarkte, Hirnabszesse und Meningitiden ergaben ebenfalls positive Szintigramme. RESUMEN Exploraciones del cerebro en el grupo de edad pediatrica Entre enero de 1964 y enero de 1967, se realizaron exploraciones cerebrales con Tacnetium-99m pertecnetata en 130 ninos en el Baptist Hospital de Norte-Carolina. Habia 38 resultados positivos; se hallo que 25 ninos tenfan neoplasmas intracraneales y la explor-acion cerebral localizo 20 (un 80 por ciento) de estos. De los 14 tumores colocados en la fosa posterior, la exploration senalo 13 (un 93 por ciento de precision). Solo 7 de 11 tumores supratentoriales se demostraron (un 63 por ciento de precision). Otras lesiones, tales malformaciones A-V, infartacion cerebral, abscesos cerebrales, y meningitis, se mostraron por medio de las exploraciones
Preparation of reverse osmosis membranes by plasma polymerization of organic compounds

The plasma polymerization of organic compounds was used to prepare a composite reverse osmosis membrane which consists of an ultrathin semipermeable membrane formed by plasma polymerization of an organic compound or compounds and a porous substrate. Many nitrogen-containing compounds (aromatic amines, heteroaromatic compounds, aliphatic amines, and nitriles) were found to yield excellent reverse osmosis membranes by plasma polymerization directly onto porous substrates such as Millipore filters, porous polysulfone filters, and porous glass tubes. Factors involved in the preparation of reverse osmosis membranes by plasma polymerization were investigated and discussed. The plasma polymerized membranes have the following unique features: (1) very stable performance independent of salt concentration and applied pressure (practically no water flux decline was observed with many membranes): (2) salt rejection and water flux both increase with time in the initial stage of reverse osmosis (consequently, the performance of the membrane improves with time of operation); (3) very high salt rejection (over 99%) with high water flux (up to 38 gfd) can be obtained with 3.5% NaCl at 1500 psi (membranes perform equally well under conditions of sea water conversion and brakish water treatment).
Physician attitudes, opinions, and referral patterns: comparisons of those who have and have not taken an allergy/immunology rotation.

Background Interest in the field of allergy/immunology (A/I) is increasing, yet resident training programs are under pressure to shorten elective rotations such as A/I. It is unclear if there are differences between those who have and have not taken an A/I rotation. Objective To evaluate differences in the attitudes, opinions, and referral patterns between physicians who have and have not taken an A/I rotation. Methods An anonymous questionnaire was sent to 375 primary care physicians at one academic medical center. Subjects were separated into 5 cohorts based on specialty and level of training (internal medicine faculty, internal medicine resident, pediatric faculty, pediatric resident, and internal medicine–pediatric resident). Results Of the participants, 227 (61.0%) completed the survey. Compared with those who had not taken an A/I rotation, those who had taken an A/I rotation were more likely to feel they knew the types of cases seen by an allergist (75.9% vs 33.3%), to feel they knew an adequate amount about A/I (59.3% vs 19.5%), to feel they were exposed to an adequate amount of A/I during residency (64.8% vs 9.8%), to view immunotherapy as effective (70.0% vs 52.3%), and to have referred a patient to an allergist (77.8% vs 46.0%). Conclusions There are significant differences in the attitudes, opinions, and referral patterns between physicians who have and have not taken an A/I rotation. Allergic diseases are increasing, yet residency training programs are under pressure to shorten rotations such as A/I to accommodate federally mandated work hour restrictions. The potential for inadequate care of allergic diseases may be an important issue if these trends continue.
Uncertain income and redistribution in a federal system

Abstract This paper considers income redistribution in a federal system where regions experience random shocks. Federal redistribution serves as insurance against jurisdiction-specific shocks, but provides a uniform assistance to the poor and cannot suit individual jurisdictions' demands for redistribution. Consequently, whether the federal government should redistribute depends on the advantage of pooling the risk and the disadvantage of compromising different preferences for redistribution. With mobile individuals, federal redistribution loses its advantage, because migration ensures the equalization of factor incomes between regions, and because even local redistribution serves as insurance. However, local redistribution creates fiscal externalities and distorts the allocation of labor.
Reading Acquisition of Preschool Children without Systematic Instruction.

Abstract The case study method was used to investigate the reading development of six preschool children who learned to read at home without systematic intruction. The main objectives of the study were (1) to find out whether there was an identifiable process by which these children learned to read and (2) to study the role of the parents in these children's early reading acquisition. Findings indicate (1) an evolving process of reading acquisition for each subject; (2) a strong similarity in the process of reading acquisition across subjects; (3) a sequential nature of reading development in the six children; and (4) the instrumentality of parents in facilitating the reading development of their children (although parents' help seemed to be mostly spontaneous, intuitive, and unplanned). Based on findings of this study, a model is proposed to describe possible stages in the reading development of preschool children who do not experience systematic instruction.
Mechanisms of Oscillatory Reactions Deduced from Bifurcation Diagrams.

The classification/categorization of oscillatory chemical reactions and the determination of the connectivity of species in a reaction mechanism can be deduced from several experiments. In this article we show the same for bifurcation diagrams. We construct such diagrams for skeletal models of each of the known categories; these are distinct and can be used for the classification of species essential for oscillations and for the categorization of oscillatory reactions. The bifurcation diagrams are closely related to the concentration shift matrix. Prototypes of categories 1B and 1C are extended by adding nonessential species. By assuming that in a flow-through stirred reactor bifurcation diagrams for each pair of constraints (the inflow concentrations and the flow rate) can be measured, we are able to determine the category of the examined oscillator and also deduce the connectivity of the corresponding reaction network. Bifurcation diagrams possess a cusp region with specific tilt. This information together with the knowledge of a concentration shift across the saddle-node bifurcation provide the clues for categorization as well as for the reconstruction of the network's connectivity. As an example, we present an analysis of the Belousov-Zhabotinsky reaction represented by the Field-Koros-Noyes mechanism and discuss the feasibility of reconstruction of the mechanism from experiments.
The structural determination of monolayer CH2D2 adsorbed on NaCl(100) by infrared spectroscopy

Abstract The structure of monolayer CH 2 D 2 adsorbed on NaCl(100) is explored through the photometry of the polarized infrared spectra. A previous study of CH 4 on NaCl(100) was unable to distinguish between two methane conformations within the monolayer. One conformation is the tripod with three hydrogens against the surface and one pointing away. The dipod conformation has two hydrogens down and two hydrogens up. Since several distinct molecular orientations can bond to the NaCl surface simultaneously within each conformation, a theoretical model is developed to account for these geometric permutations in the monolayer. The polarized spectroscopic data are presented along with the theoretical model. An analysis of the data and the proposed model conclusively establishes a tripod conformation of the monolayer methane molecules over the NaCl(100) surface.
The process of organ donation and its effect on consent.

Objective: To identify those factors that enhance or inhibit organ donation in order to provide data to help policy makers, hospital administrators and transplantation professionals make informed choices about how to modify the donor system and to structure ‘best practice’ interventions. Summary of background data: Legislative efforts to increase donation rates have not been successful. An emphasis on process is needed to help explain this. Methods: The study was conducted using a stratified random sample of 23 hospitals in the Pittsburgh and Minneapolis/St Paul standard statistical metropolitan areas. Each week, the medical charts of all in-patient and emergency room patient deaths at each hospital were reviewed using a standardized review protocol to determine eligibility for organ, tissue, and cornea donation. A total of 10 681 patient charts were reviewed over a 4-yr period. Eight hundred and twenty-eight cases out of 1 723 eligible cases were selected for inclusion in the study. Data were collected on 827 of these cases. All health care providers (HCPs) who spoke with the family after the patient's death or discussed donation with the family were interviewed. Results: Of the 10 681 patient charts reviewed, 16.5% were eligible to donate either organs, tissues, or corneas, and 87.0% of donor-eligible patients’ families were approached and asked to donate. Consent rates were 23.5% for corneas, 34.5% for tissues, and 46.5% for organ donation. Multiple logistic regression demonstrated that the best and strongest predictor of donation decisions was the family's initial response to the donation request, as reported by the HCP. Three initial response groups are examined and compared. Those families who expressed an initially favorable reaction were most likely to agree to donation. Furthermore, discussion patterns differed by initial reaction group, with families who expressed initial indecision about donation sharing more characteristics with families who were not favorable than those who were favorable. More detailed information was provided to the favorable families, as compared to the other two groups, concerning the effect of donation on funeral arrangements and costs. Families who were favorable were also more likely to meet with an organ procurement organization representative than were other families. The strongest predictor of a family's unfavorable response to a donation request was the belief that the patient would have been against donation. A number of other variables, including HCP attitudes, also had an impact on the family's decision to donate. Conclusions: A number of discussion and HCP characteristics are associated with a family's willingness to consent to organ donation. Further study is needed to determine if interventions based on the characteristics identified in this study will increase consent to donation.
Application of near-infrared spectroscopy during fetal cardiac surgery.

Background Near-infrared spectroscopy (NIRS) has been shown to provide reliable noninvasive monitoring of regional oxygenation in a variety of clinical settings. We set out to test its feasibility as a monitor of fetal and placental oxygenation during fetal cardiac surgery. Materials and Methods Six ovine fetuses from 98–110 ds gestation were placed on fetal bypass for 30 min and followed post-bypass for 2 h. A NIRS probe (MI INVOS 5100B; Somanetics, Troy, MI) was placed on the pregnant uterine horn during and after fetal surgery. NIRS values were compared with blood gas values obtained by direct sampling from umbilical circulation. Results NIRS values positively correlated with umbilical venous oxygen saturation (R 2 = 0.891, P 2 = 0.810, P 2 , and fetal arterial pH, pO 2 , and oxygen saturation. Conclusions This is the first report of application of NIRS in the setting of fetal surgery. NIRS permits noninvasive assessment of placental oxygen saturation and pO 2 . This technology is a simple and useful tool for real-time monitoring of oxygen delivery to the fetus during maternal–fetal cardiac interventions and of overall well-being of the fetal-placental unit.
ESTIMATING THE MAXIMUM (MINIMUM) OF A QUADRATIC FUNCTION UNDER CERTAIN CORRELATION PATTERNS

Summary May nonidentity error correlation patterns encountered in regression theory allow computationally efficient techniques for modifying the usual procedures for constructing confidence intervals and performing F-tests so that valid inferences can be drawn. Such techniques are explored in light of the general theme of this note.
A continuous-time generalization of Gordan's transposition theorem

Abstract A certain infinite-dimensional generalization of Gordan's transposition theorem is obtained as a consequence of a strong duality principle in continuous-time programming. Some implications and corollaries of the main theorem are also discussed.
Screened Coulomb interaction or Hubbard model

Abstract We examine the screened Coulomb interactions for quasiparticles near the Fermi surface of isotropic metals and determine a semiquantitative best fit to the Hubbard model. Does such a fit exist for a layered metal (a stack of 2D conductors) in which screening currents do not flow easily from plane to plane? The answer again, is yes. Although they are not necessarily repulsive, the screened interplanar forces are, in fact, generally negligible.
Changes in the corpuscles of Stannius of coho salmon (Oncorhynchus kisutch) during smoltification and seawater adaptation.

Abstract Two types of cells (type 1 with large granules and type 2 with small granules) are present in the corpuscles of Stannius of the coho salmon, Oncorhynchus kisutch , during smoltification. The cells increase in size during normal smoltification and are equally large in freshwater and seawater smolts; in abnormal stunted fish in seawater the mean cell size is similar to that characteristic of parr. Nevertheless, the predominant type 1 cells (as well as the less frequent type 2 cells) in stunts appear active and are relatively depleted of granules. Type 1 cells may be associated with hypocalcin secretion; release of this hormone may be greater in stunts than in normal seawater smolts, possibly owing to initial difficulty of these incompletely smoltified fish to adjust to the seawater environment.
Acreage response to price and risk: The case of tobacco in Malawi

This article presents an empirical investigation of the importance of price and its riskiness among Malawi's commercial and smallholder tobacco producers. Employing a simple econometric risk model, the study finds commercial farmers to be both price-responsive and risk-averse. The response is, however, inelastic. Price risk is empirically less important among smallholder farmers. Substantial bias in estimated coefficients and overall model performance are observed when risk variables are omitted from the equation. This underscores the importance of risk consideration in supply response analyses. Copyright 1991 by Oxford University Press.
Sub-micron-scale trace-element distributions in natural zircons of known provenance: implications for Ti-in-zircon thermometry

NanoSIMS measurements of Ti, P, Y, Ce, and Hf in zircon separates from the Youngest Toba Tuff, the Bishop Tuff, the Quottoon Igneous Complex, the Sierra Nevada batholith, and an Adirondack migmatite show that micron-scale oscillatory zoning of Ti is common. The zircons we have studied typically display banded concentration gradients, having between 1 and 7 peaks in Ti abundance over length scales of 10–20 μm—the beam diameter commonly used for SIMS trace-element zircon analyses—with amplitudes of up to 4.5 ppm Ti (baseline values are ~1–4 ppm) and widths (measured at half-height) of between ~0.2 and 4 μm. Spatial correlations between concentrations of Ti and other trace elements (P, Y, and Ce) are also common, but variable in character, ranging from oscillatory co-variation of Ti, P, Y, and Ce to cases where only a subset of peaks for a given element is spatially correlated with peaks in Ti. There are also longer length-scale, generally positive correlations among concentrations of Ti, P, Y, and Ce (i.e., gradients on which narrower peaks are superimposed). In contrast, Hf concentrations are either uncorrelated or inversely correlated with these longer length-scale variations in Ti concentrations. The wide range in Ti concentrations over distances of less than 1 μm and the various correlations between Ti concentrations and those of the other analyzed elements suggest that on the micron scale and at temperatures between ~700 and 800 °C, zircon-liquid Ti partitioning is not controlled by bulk or lattice equilibrium. Treating our NanoSIMS Ti ion maps as though they were conventional SIMS analyses (i.e., generating an average Ti concentration for each map), we evaluate the hypothesis that while micron-scale variations in Ti concentrations might be kinetically controlled, when averaged over 100–400 μm2, such variations capture the thermal state of the growing zircon. Using these average Ti concentrations, independent petrologic pressure and temperature constraints, estimates of silica and titania activities based on phase assemblages as well as calculations using rhyolite-MELTS, we show that crystallization temperatures predicted by Ti-in-zircon geothermometry generally do not agree with the independently constrained temperatures for the samples.
Reframing Urban Education Discourse: A Conversation With and for Teacher Educators

This article represents a conversation between two urban educators—one African American and one White. Not only the influence of race, but also the influence of personal and cultural histories on urban classrooms and colleges, unfold during their conversation. Providing important insights into the nature and significance of the work of urban education, their dialogue also demonstrates the need for, and examples of, multiple divergent voices in the struggle for practical and theoretical thinking in urban education to give direction to meaningful improvements.
Lifestyle Exercise Inventory: Preliminary Development

Drawing from the Theoretical Pattern of Physical Activity Model of Blair, Kohl, and Gordon, a Lifestyle Exercise Inventory was developed. The internal consistency (.69, n = 178), test-retest reliability (.77), and criterion validity (-.27, .29, .32, and .32) of the measure are reported for 178 women.
Single-photon turnstile device based on Coulomb blockade of electron and hole tunneling in p-i-n heterojunctions

We describe a single-photon turnstile device that is based on a double-barrier mesoscopic p-i-n heterojunction driven by an alternating voltage source. In such a semiconductor device, Coulomb blockade and quantum confinement effects together can suppress the quantum fluctuations usually associated with electron and hole injection processes. It is therefore possible to generate heralded single-photon states without the need for high-impedance current source. The present scheme promises high- precision photon-flux state and current standards, as the repetition rate of the single-photon states and the magnitude of the junction current are determined by the frequency of the alternating voltage source.
“I got your back”: an examination of the protective function of gang membership in adolescence

The threat of victimization has been regarded as a central feature in both the development and the continuation of youth gangs. Although many studies find the need for protection to be a common reason youth join gangs, recent literature suggests that gang members are at an increased risk of victimization. Given this seeming contradiction between expectations and reality, the current article examines the “objective” and “subjective” dimensions of gang member victimization using panel data collected from youth between the ages of 10 and 16 years. Findings reveal that gang members report higher levels of actual victimization and perceptions of victimization risk than non-gang-involved youth. Gang membership is associated with reduced levels of fear, however. Overall, although gangs may not be functional in terms of actual victimization, they seem to decrease anxiety associated with the threat of future victimization.