cssi/SciSciGPT-SciSciNet huggingface dataset:
Use Of Structure Maps To Facilitate Problem Solving In Algebra‐Based Physics

In this study we explore the use of expert‐designed structure maps by students in an algebra‐based physics course and the evolution of these maps based upon students’ reactions and feedback collected over one semester. The participants were trained to use structure maps while solving problems sharing similar deep‐structure elements. They met for one hour every week to work on the problems using the maps. We report here on the ways in which students used the structure maps during the interviews, the difficulties faced by students as they attempted to use these maps as well as the feedback offered by students regarding the maps. We also report on how we changed the maps based on feedback from the students and to facilitate their use during problem solving.
Sustainability in Science Education? How the Next Generation Science Standards Approach Sustainability, and Why It Matters

In this essay, we explore how sustainability is embodied in the Next Generation Science Standards (NGSS), analyzing how the NGSS explicitly define and implicitly characterize sustainability. We identify three themes (universalism, scientism, and technocentrism) that are common in scientific discourse around sustainability and show how they appear in the NGSS. Taken together, these themes evoke a technology-centered perspective called ecological modernization that defines sustainability as a set of global problems affecting all humans equally and solvable through the application of science and technology. We argue that students who are taught to think about sustainability from this perspective will be less able to see its ethical and political dimensions and less prepared for the political realities of a pluralist, democratic society that must balance the needs of multiple groups and integrate science with other sources of knowledge to develop contextualized responses to sustainability challenges. One compelling alternative is a systematic collaboration between science educators and social studies educators, in which the complementary pedagogical strengths of both fields are combined to provide realistic and powerful preparation for future sustainability challenges.
IMPLOSION MEASUREMENTS IN A HIGH VOLTAGE, LARGE DIAMETER, MEDIUM DENSITY THETA-PINCH

Extensive sets of density measurements were obtained for two preionization levels with other parameters held constant (B = 0.5 T, n$sub 0$ = 4.8 x 10$sup 14$ cm$sup -3$, E/sub theta/ = 1 kV/cm). The gross features of the implosion are similar in the two cases, but the density front is double-peaked for the higher preionization case. Generally, the particles move ahead of the driving magnetic field front, but some are also within this front. After reaching the axis the imploding plasma is observed to move outward again through the magnetic field in a manner suggesting anomalous transport. The particles stop at the outer radii. The total number of particles increases during the implosion and thereafter remains about constant. (auth)
Surgical Treatment of Sand Colic Results in 40 Horses

A retrospective study of 40 horses that underwent surgical treatment for sand colic was performed. Three horses were euthanatized and one died during surgery. Of the 36 horses that recovered from anesthesia, five died before discharge from the hospital and seven died after discharge. Twenty-four horses survived at least 12 months. Sand impaction of the right dorsal colon was present in 26 horses. In addition to sand impaction, 10 horses also had colonic displacement or volvulus.
What is Health? A Multiple Correspondence Health Index

This paper illustrates a health index that uses multiple correspondence analysis to reduce multiple discrete indicators to a continuous variable using minimal modeling assumptions. The continuous index enables fixed effects estimators when health is the dependent variable, and it exhibits more variation than self-assessed health (SAH) to support identification when health is an independent variable. I compute this index for 18 waves of the British Household Panel Survey, describe its features, and compare its use to SAH. The index performs better in dynamic models of health and subsumes the explanatory power of SAH in wage equations.
Subnormal structure of the general linear groups over Banach algebras

Let GLnA be the group of invertible matrices over a ring A and EnA the subgroup generated by elementary matrices. In previous papers, the author described all subgroups of GLnA, n≥3, normalized by EnA for a few classes of rings A including all Banach algebras A with 1 (in the case n=2, the situation is more complicated). The present paper extends this to a wider class of rings. However, the main goal is to give a complete description of all subnormal subgroups of EnA for this class of rings including all Banach algebras A with 1.
Complement depletion enhances pulmonary inflammatory response after liver injury.

Hepatic cryoablation can produce acute lung injury, with activation of nuclear factor (NF)-кB in the remnant liver and lungs, production of C-X-C chemokines, and neutrophil infiltration of the lungs. Ac-tivated complement stimulates NF-к B and cytokine secretion from Kupffer cells. The role of comple-ment in the development of acute lung injury after cryoablation was examined using HLL transgenic mice (5’ HIV-LTR-Luciferase gene; 5’ HIV-LTR is an NF-к B-dependent promoter). Total comple-ment depletion was achieved with preoperative administration of cobra venom factor (CVF). After he-patic cryoablation, bioluminescent NF-кB activity increased in the nonablated liver remnant by 4 hours in both control (119,093 ± 22,808 net RLU/mg protein) and CVF-treated mice (117,722 ± 14,932) from cumulative baseline (657 ± 90, P < 0.0001). In the lung, complement-depletion induced significantly greater increases in NF-к B activation at both early and later times. Likewise, chemokines were higher in complement-depleted mice relative to controls (KC: 493 ± 43 versus 269 ± 29 pg/mg protein, P < 0.001; MIP-2: 171 6 29 versus 64 6 13 pg/mg protein, P < 0.0001). Pulmonary myelo-peroxidase activity was equivalent at 24 hours, but complement-depletion caused a significantly more rapid influx of neutrophils. Complement depletion results in increased pulmonary inflammation follow-ing liver cryo injury via relative upregulation of NF-к B activity. Activated complement is not the initiator of the systemic inflammatory response; in fact, downstream components of the complement cascade may diminish subsequent inflammation.
Accounting for the Contradictory Organizational Consequences of Information Technology: Theoretical Directions and Methodological Implications

Although much contemporary thought considers advanced information technologies as either determinants or enablers of radical organizational change, empirical studies have revealed inconsistent findings to support the deterministic logic implicit in such arguments. This paper reviews the contradictory empirical findings both across studies and within studies, and proposes the use of theories employing a logic of opposition to study the organizational consequences of information technology. In contrast to a logic of determination, a logic of opposition explains organizational change by identifying forces both promoting change and impeding change. Four specific theories are considered: organizational politics, organizational culture, institutional theory, and organizational learning. Each theory is briefly described to illustrate its usefulness to the problem of explaining information technology's role in organizational change. Four methodological implications of using these theories are also discussed: empirical identification of opposing forces, statement of opposing hypotheses, process research, and employing multiple interpretations.
Magnetic properties of K/T and E/O microspherules: origin by combustion?

Abstract Magnetic spherules and spheroids are found in association with Ir anomalies at the Cretaceous/Tertiary (K/T) boundary and near to the Eocene/Oligocene (E/O) boundary. Detailed magnetic analyses have been performed on these particles, and on bulk K/T boundary clay from marine and continental sections. Coercivity spectra, and blocking and Curie temperatures of the spheroids and K/T boundary clays have been determined, and natural remanence and susceptibility measured for the bulk clay and associated strata. Marine K/T boundary clays are strongly magnetic, with remanent coercivities similar to those of the spheroids. In contrast, the continental clays are diamagnetic, except for the thin, overlying “impact layer”, which contains abundant paramagnetic jarosite, along with shocked quartz and feldspar. The morphologies, mineralogies, and magnetic properties of the K/T magnetic spheroids are closely analogous to magnetic fly ash spherules. This similarity may be related to the presence of carbonaceous “soot” particles in some marine K/T boundary clays, and the recent identification of plerospheres and cenospheres in continental boundary clay. In contrast, tektites and microtektites differ from the K/T magnetic spherules in a number of fundamental ways. The late Eocene particles are magnetically distinct from the K/T spheroids, both in their coercivity and thermal spectra. INAA results on Upper Cretaceous combustible shales indicate that the anomalous abundances of certain chalcophile and lithophile elements at the K/T boundary may be explained in terms of the natural combustion of bituminous sediments.
Minimal bases and maximal nonbases in additive number theory

Abstract An asymptotic basis A of order h is minimal if no proper subset of A is an asymptotic basis of order h. Examples are constructed of minimal asymptotic bases, and also of an asymptotic basis of order two no subset of which is minimal. If B is a set of nonnegative integers which is not a basis (resp. asymptotic basis) of order h, but such that every proper superset of B is a basis (resp. asymptotic basis) of order h, then B is a maximal nonbasis (resp. maximal asymptotic nonbasis) of order h. Examples of such sets are constructed, and it is proved that every set not a basis of order h is a subset of a maximal nonbasis of order h.
Pregnancy rates after hysteroscopic polypectomy and myomectomy in infertile women.

Abstract Objective: To compare reproductive benefits of hysteroscopic myomectomy and polypectomy for infertility to outcomes in infertile couples with normal hysteroscopic findings. Methods: Women with diagnoses of infertility who had hysteroscopic evaluations by a single surgeon between 1975 and 1996 were sent a routine follow-up questionnaire regarding their reproductive histories. All 92 subjects who were located responded to the questionnaire, and 78 met inclusion criteria: age under 45 years, at least 12 months of infertility, and at least 18 months of follow-up with attempts to conceive, including in vitro fertilization in women with bilateral tubal occlusion. Results: Of the 78 subjects, 36 had myomectomies, 23 had polypectomies, and 19 had normal cavities. Among the three groups, there were no significant differences in age, type of infertility, length of infertility, or follow-up after the procedure. Polypectomy subjects had significantly higher pregnancy and live birth rates than women with normal cavities. Women who had myomectomies larger than 2 cm had significantly higher pregnancy and live birth rates, achieving statistical significance at a myoma size of 3 cm or greater for live births. Spontaneous abortion rates among first pregnancies after myomectomy, polypectomy, or normal study were similar: 31.5%, 27.7%, and 37.5%, respectively. Conclusion: Both hysteroscopic polypectomy and hysteroscopic myomectomy appeared to enhance fertility compared with infertile women with normal cavities. Despite concern that hysteroscopic resection of a large myoma might ablate a large surface area of the endometrial cavity, the reproductive benefit appears greater than the risk.
Phonology and the development of the lexicon: evidence from children's errors.

Various kinds of children's lexical errors, mostly based on similarity in sound, are presented and classified. At the earliest stage some children are found to pursue a HOMONYM STRATEGY, actively seeking to combine adult word-patterns to limit their output repertoire. The associations between words underlying these productive homonyms, together with perception-based errors, blends, and other word-substitutions, are compared with malapropisms from a slightly older group of children as well as with data from adults. Analysis of these data makes it possible to chart developmental changes in the phonological links which form one substructure of the lexicon.
Difficulties In Enterprise System Implementation: The Case Of Millicent Homesbfdgfd

AbstractMany large manufacturing companies in the U.S. have implemented ERP systems. However, difficulties in ERP implementation continue to persist despite decades of practical experience and academic research. This case describes several issues that were encountered during the implementation of SAP at Millicent Homes, a residential construction company with several markets in the U.S. In particular, the case emphasizes the functional and technical issues that befell the implementation and their interaction with organizational implementation issues. The case is unique in that while Millicent Homes was implementing SAP, SAP was concurrently developing an industry solution for engineering and construction companies as well as the beta version of its portal. In addition, the home construction industry provides an interesting setting for examining the adoption of new systems.
Adsorption behavior and potential interfacial morphology : Impact of adsorbing hydrophobic groups in polymers with weakly adsorbing main backbones

This study examined the adsorption isotherm behavior within a homologous series of fluorescently end-labeled hydrophobically end-modified (“fluorophobe”) poly(ethylene oxide)s (PEOs) on hydrophobic polystyrene (PS) latex. Results were then compared with a model for the adsorption of end-modified chains and previous adsorption studies of associative thickeners, PEOs containing hydrophobes on both ends in addition to regularly spaced weak internal hydrophobes. For both PEO series, an increase in end-group hydrophobicity yielded higher isotherm plateau coverages by up to a factor of 5 over control samples without end hydrophobes. For the fluorophobe-PEOs, an increased end-group hydrophobicity also led to a steeper slope in the low-concentration regime of the isotherm, reflecting the influence of the end group on the net adsorption energy (to the extent that the initial isotherm slope reflected an equilibrium partitioning between the interphase and the bulk). In contrast for the associative thickeners, the impact of end-group hydrophobicity on the initial isotherm slope was not apparent, and the initial slopes for the associative thickeners were generally much steeper than for any of the fluorophobe PEOs. These differences in isotherm shapes were thought to reflect differences in the molecular architecture between the fluorophobe-PEO and associative thickener series, and the impact of molecular architecture on the interaction with the substrate. In addition to altering the coverage, the end-group hydrophobes alter the interfacial morphology and the surface selectivity for specific molecular weight populations within a polydisperse PEO sample. © 1995 John Wiley & Sons, Inc.
Aminosilanes Grafted to Basic Alumina as CO2 Adsorbents—Role of Grafting Conditions on CO2 Adsorption Properties

Solid oxide-supported amine sorbents for CO2 capture are amongst the most rapidly developing classes of sorbent materials for CO2 capture. Herein, basic γ supports are used as hosts for amine sites through the grafting of 3-aminopropyltrimethoxysilane to the alumina surface under a variety of conditions, yielding the expected surface-grafted alkylamine groups, as demonstrated by FTIR spectroscopy and (29)Si and (13)C cross-polarization magic-angle spinning (CPMAS NMR) spectroscopy. Grafting amine sites on the surface in the presence of water leads to a high density of amine sites on the surface whereas simultaneously creating a unique type of aluminum species on the surface, as demonstrated by both 1D and 2D (27)Al MAS NMR spectroscopy. The thus prepared sorbents result in higher CO2 adsorption capacities and amine efficiencies compared to sorbents prepared in the absence of water or similar amine loading sorbents prepared using silica supports. In situ FTIR spectra of the sorbents exposed to CO2 at various pressures show no distinct difference in the nature of the adsorbed CO2 species on alumina- versus silica-supported amines, whereas water adsorption isotherms show that the improved performance of the amine-grafted alumina support is not a consequence of retained water on the more hydrophobic aminoalumina materials. The findings demonstrate that amine-grafted, basic alumina materials can be tuned to be more efficient than the corresponding silica-supported materials at comparable amine loadings, further demonstrating that the properties of amine sites can be tuned by controlling or adjusting the support surface properties.
Diversity of Metabolic Patterns in Human Brain Tumors: Enzymes of Energy Metabolism and Related Metabolites and Cofactors

Biopsies from 15 human gliomas, five meningiomas, four Schwannomas, one medulloblastoma, and four normal brain areas were analyzed for 12 enzymes of energy metabolism and 12 related metabolites and cofactors. Samples, 0.01-0.25 microgram dry weight, were dissected from freeze-dried microtome sections to permit all the assays on a given specimen to be made, as far as possible, on nonnecrotic pure tumor tissue from the same region. Great diversity was found with regard to both enzyme activities and metabolite levels among individual tumors, but the following generalities can be made. Activities of hexokinase, phosphorylase, phosphofructokinase, glycerophosphate dehydrogenase, citrate synthase, and malate dehydrogenase levels were usually lower than in brain; glycogen synthase and glucose-6-phosphate dehydrogenase were usually higher; and the averages for pyruvate kinase, lactate dehydrogenase, 6-phosphogluconate dehydrogenase, and beta-hydroxyacyl coenzyme A dehydrogenase were not greatly different from brain. Levels of eight of the 12 enzymes were distinctly lower among the Schwannomas than in the other two groups. Average levels of glucose-6-phosphate, lactate, pyruvate, and uridine diphosphoglucose were more than twice those of brain; 6-phosphogluconate and citrate were about 70% higher than in brain; glucose, glycogen, glycerol-1-phosphate, and malate averages ranged from 104% to 127% of brain; and fructose-1,6-bisphosphate and glucose-1,6-bisphosphate levels were on the average 50% and 70% those of brain, respectively.
Intimations of jewish survival: Comments on klausner’s paper

The Christian or Islamic hegemony that motivated conversion in the Middle Ages and sustained the ontological plausibility of Judaism may no longer be effective. Nevertheless, present-day American Judaism, a highly voluntaristic religion, has proved to be a life-enhancing identity for many and may continue to do so. Factors favoring Jewish survival are identified.
Possible ball court at La Venta, Mexico.

LA VENTA, one of the earliest Olmec sites, is located on an island in the Tonala River which forms the boundary between the Mexican states of Veracruz and Tabasco (18° 10′N, 94° 5′ W). The site is believed to have been built and maintained during the period from 1000 BC to 600 BC or even later1, primarily as a ceremonial or religious enclave2. For years, no ball court, usually an important feature of sacred Mesoamerican precincts, had been found at La Venta3.
Real-time PCR quantification of a green fluorescent protein-labeled, genetically engineered Pseudomonas putida strain during 2-chlorobenzoate degradation in soil

The potential for real-time PCR (RTm-PCR) detection of the genetically engineered strain Pseudomonas putida GN2 was studied during 2-chlorobenzoate (2-CB) degradation in three different soils. The strain contained the constructed plasmid pGN2 which encoded genes for 2-CB oxidation (cbdA) and the green fluorescent protein (gfp). P. putida GN2 numbers were assessed by plating onto 2-CB minimal media and also by RTm-PCR detection of cbdA and gfp. Addition of P. putida GN2 decreased the time required to degrade 2-CB in all tested soils by more than 7 days. The RTm-PCR estimations of P. putida GN2 numbers strongly correlated with those obtained from plate count methods during active 2-CB degradation. However, after 2-CB degradation in the soils had ceased, RTm-PCR estimations of cbdA and gfp genes were generally one order of magnitude lower than those from plate counts. These results indicate the potential for RTm-PCR to rapidly determine degrader numbers in soil following bioaugmentation but also the need to exercise caution when attempting to determine cell numbers of degraders from the RTm-PCR quantification of plasmid encoded genes after substrate is depleted.
Selection Criteria for Internships in Clinical Neuropsychology

Criteria used in the evaluation and selection of applicants for clinical neuropsychology internships were identified by a survey of programs that met guidelines for specialty training. The number of internships that offer training with specialization in clinical neuropsychology has more than doubled during the past 10 years. Supervising neuropsychologists from 75 programs replied to the survey, yielding a 72.8% response rate. Clinical experience in neuropsychological assessment, specialization in clinical neuropsychology during graduate education, personal interview, and letters of recommendation were reported to be the most salient selection criteria. Practica that provide experience with flexible or functional systems assessment approaches at university-affiliated or VA (U.S. Department of Veterans Affairs) medical centers and doctoral curricula that follow International Neuropsychological Society/Division 40 course guidelines, with teaching and supervision provided by neuropsychologists, were preferred prerequisites to internship. These results are consistent with selection criteria reported over a decade ago and indicate continued endorsement of the vertically integrated model of education and training outlined by the Houston Conference on Specialty Education and Training in Clinical Neuropsychology.
A parametric approach to shape field-relevant blast wave profiles in compressed-gas-driven shock tube.

Detonation of a high explosive produces shock-blast wave, shrapnel, and gaseous products. While direct exposure to blast is a concern near the epicenter, shock-blast can affect subjects even at farther distances, which is termed as primary blast injury, which is the theme of this work. The shock-blast profile is characterized with blast overpressure, positive time duration, and impulse as shock-blast wave parameters (SWPs). These parameters in turn are a function of field factors, such as the strength of high explosive and the distance of the human subjects from the epicenter. The shape and magnitude of the profile determine the severity of injury to the subjects. As shown in some of our recent works (Chandra et al., 2011;Sundaramurthy et al., 2012;Skotak et al., 2013), the profile not only determines the survival of the animal but also the acute and chronic biomechanical injuries along with the following bio-chemical sequelae. It is extremely important to carefully design and operate the shock tube to produce field relevant SWPs. Furthermore, it is vital to identify and eliminate the artifacts that are inadvertently introduced in the shock-blast profile that may affect the results. In this work, we examine the relationship between shock tube adjustable parameters (SAPs) and SWPs that can be used to control the blast profile; the results can be easily applied to many of the laboratory shock tubes. Further, exact replication of shock profile (magnitude and shape) can be related to field explosions and can be a standard in comparing results across different laboratories. 40 experiments are carried out by judiciously varying SAPs such as membrane thickness, breech length (66.68 to 1209.68 mm), measurement location, and type of driver gas (nitrogen, helium). The relationships between SAPs and the resulting shock-blast profiles are characterized. Finally, shock-blast profiles of a TNT explosion from ConWep software is compared with the profiles obtained from the tube.
On comparing different tests of the same hypothesis

a series of small samples of real data has been examined by Pearson & Haines (1935) who plotted w against s in a control chart situation. With the help of the known standard deviation cr they were able to insert on their diagrams a grid of several upper- and lowerpercentage points of bothwands so that the corresponding degrees of significance attained by any sample and the agreement in this respect could be seen on inspection. A similar approach, but based on experimental sampling from normal populations, was used by Eisenhart & Swed (1940) to compare two possible tests of the homogeneity of several estimates of variance. In the null case they found considerable disagreement at the 5 % level of significance. More recently Cox (1956) has discussed some general aspects of this problem. We now restate and add to some of his arguments: (a) The case for a particular quick test is strengthened if it is known that it will nearly always lead to the same action as the standard test. (b) Quick tests are often used in preliminary or spot analyses. It seems highly desirable that the conclusions so reached should not be seriously upset if a fuller analysis is carried out. The quick test should inspire confidence in this respect even if it will not be followed up at all. (c) The method of data collection or experimentation may lend itself to a particularly advantageous use of quick tests; indeed, the experimental approach may be modified for this reason. To be specific let us consider a life test on items with a normal distribution, N(0, cr2), of lives. The test may be stopped as soon as just over half the items in it have failed. If cr2 is assumed known a very simple test on 0 may be based on the sample median. One could, of course, improve the analysis by using all the available observations and not only the median. More fundamentally, the experimental method hinges on the fact that it allows a quick decision to be reached. Confidence in the reliability of this approach is presumably based on the knowledge that the median leads to a reasonably powerful test, but also on the supposition that the conclusion reached with the censored test would generally be confirmed were the test in fact run to completion. A similar point could be made in comparing the paired t-test and the sign test: not only does the sign test rest on fewer assumptions, it also allows a simplification of experimental technique.
Structural Variation in the Sperm Ducts of Procambar Us (Decapoda, Cambaridae)

Des differences microscopiques distinctes existent entre les conduits spermatiques droit et gauche de beaucoup de representants du genre Procambarus. Ces differences portent sur le degre d'enroulement, le diametre et l'opacite. De telles variations ne sont pas apparentes chez les mâles des genres Orconectes et Cambarus. Une etude histologique des conduits spermatiques a ete effectuee en microscopie photonique et electronique. La couche epitheliale, la musculature, et le contenu des conduits dans les regions proximale, mesiale et distale sont decrits. Les aspects fonctionnels des deux conduits sont envissages.
Nature and interrelations of fast dynamic properties in a coarse-grained glass-forming polymer melt

Recent experimental studies have demonstrated that the dynamics of glass-forming liquids on fast picosecond timescales are directly relevant to developing effective formulations for protein drug preservation. In these systems, short-time dynamic properties, including the Debye–Waller factor, non-ergodicity parameter, and the ‘fast beta’ relaxation time, are ‘tuned’ by the addition of antiplasticizer additives, with associated improvements in protein preservation. We employ molecular dynamics simulations of a coarse-grained polymer melt with and without the addition of an antiplasticizer additive to characterize how these fast dynamic properties interrelate and how they are altered by the addition of antiplasticizer additives. We find that the Gaussian approximation for the van Hove correlation function holds to an excellent approximation at short times, facilitating the establishment of precise interrelations between these properties and the characterization of their temperature and composition dependence. Following previous studies, we first fit the fast relaxation process to an empirical ‘stretched Gaussian’ form (exp[−(t/τ)β] with 1 < β < 2) and find that β equals 3/2 over a wide range of temperature for the post-inertial relaxation process. We then consider a more theoretically motivated description of fast beta relaxation inspired by an earlier model for the relaxation of a fractal network of elastic clusters in glass-forming colloids, and we find that this description provides an excellent fit to the entire short time relaxation over a large range of temperatures with physically meaningful parameters. Finally, we show that it is possible to tune the fast beta relaxation process with antiplasticizer additives, resulting in effects that rationally enhance protein preservation in glassy sugar matrices.
Generalized Linear Quadratic Control

We consider the problem of stochastic finite- and infinite-horizon linear quadratic control under power constraints. The calculations of the optimal control law can be done off-line as in the classical linear quadratic Gaussian control theory using dynamic programming, which turns out to be a special case of the new theory developed in this technical note. A numerical example is solved using the new methods.
The beauty in small things revealed

Oxygenic photosynthesis accounts for nearly all the primary biochemical production of organic matter on Earth. The byproduct of this process, oxygen, facilitated the evolution of complex eukaryotes and supports their/our continuing existence. Because macroscopic plants are responsible for most terrestrial photosynthesis, it is relatively easy to appreciate the importance of photosynthesis on land when one views the lush green diversity of grasslands or forests. However, Earth is the “blue planet,” and oceans cover nearly 75% of its surface. All life on Earth equally depends on the photosynthesis that occurs in Earth's oceans. A rich diversity of marine phytoplankton, found in the upper 100 m of oceans, accounts only for ≈1% of the total photosynthetic biomass, but this virtually invisible forest accounts for nearly 50% of the net primary productivity of the biosphere (1). Moreover, the importance of these organisms in the biological pump, which traps CO2 from the atmosphere and stores it in the deep sea, is increasingly recognized as a major component of the global geochemical carbon cycle (2). It seems obvious that it is as important to understand marine photosynthesis as terrestrial photosynthesis, but the contribution of marine photosynthesis to the global carbon cycle was grossly underestimated until recently. Satellite-based remote sensing (e.g., NASA sea-wide field sensor) has allowed more reliable determinations of oceanic photosynthetic productivity to be made (refs. 1 and 2; see Fig. 1). Fig. 1. Depiction of the amount of chlorophyll present in the oceans and the amount of vegetation on land. Purple and blue represent low levels of chlorophyll, and green, yellow, and red indicate progressively higher concentrations. Brown pixels show areas with little vegetation on land, and blue-green pixels represent areas of densest vegetation. [Image provided by ORBIMAGE (Copyright 2003, Orbital Imaging Corporation) and processing by NASA Goddard Space Flight Center.] In …
Twenty-four hour blood pressure monitoring in healthy children.

Blood pressure and heart rate were measured every 20 min during the day and every 30 min during the night in 105 children (51 girls and 54 boys, aged 6–10 years) with a portable automated blood pressure monitor using an oscillometric principle of measurement. The monitor was well accepted by most of the children and the rate of invalid measurements was only 13%. Mean systolic and diastolic blood pressure was 114±7/72±5 by day and 99±7/56±6 by night. The corresponding heart rates were 93±8 and 72±9 beats/min. No significant differences were found between boys and girls. At night, systolic blood pressure dropped by 13%±4%, the diastolic value by 22%±7% and heart rate fell by 22%±6%. Mean systolic and diastolic blood pressure measurements correlated positively with the subject's height, whereas no correlation was found with age.
Radiation Resistance of Cancer Stem Cells: The 4 R's of Radiobiology Revisited

There is compelling evidence that many solid cancers are organized hierarchically and contain a small population of cancer stem cells (CSCs). It seems reasonable to suggest that a cancer cure can be achieved only if this population is eliminated. Unfortunately, there is growing evidence that CSCs are inherently resistant to radiation, and perhaps other cancer therapies. In general, success or failure of standard clinical radiation treatment is determined by the 4 R's of radiobiology: repair of DNA damage, redistribution of cells in the cell cycle, repopulation, and reoxygenation of hypoxic tumor areas. We relate recent findings on CSCs to these four phenomena and discuss possible consequences.
Response-intensity modulation in long-range heteronuclear two-dimensional NMR chemical-shift correlation

Two-dimensional NMR spectroscopy has had a very significant impact on the way in which structure elucidation and spectral assignment studies are performed. Investigators have begun to exploit long-range heteronuclear coupling constants by utilizing delays in the conventional 2D NMR heteronuclear chemical-shift correlation experiment optimized for long-range magnetization transfer through two, three, and/or four bonds (‘Jcu, 3JcH, and “J,,) (1-16). Alternatively, several new experiments specifically for the observation of long-range heteronuclear spin-coupling information (14, 15, 2 7-22) have been reported. Despite the now numerous applications of longrange heteronuclear chemical-shift correlation contained in the literature, factors affecting the magnetization transfer step in these experiments have not been carefully investigated. Most long-range experiments are optimized for a 10 Hz magnetization transfer based upon the work of Reynolds and co-workers (2) or that of Wemly and Lauterwein (9), although other optimizations have also been used with success (I, 4, 10). As a consequence of the absence of responses in some of our own work despite optimization of the experiment at or near the magnitude of the coupling in question we now wish to communicate the results of our preliminary investigation into factors affecting response intensity in long-range heteronuclear chemical-shift correlation. Schenker and von Philipsborn (23) have reported a systematic investigation of the optimization of the INEPT and DEPT experiments in weakly coupled spin-f systems. They have shown that when magnetization is transferred via small heteronuclear couplings, that the transfer may be modulated by other homoand/or heteronuclear spin couplings which are experienced by those nuclei involved in the polarization transfer. Population transfer involved in the long-range heteronuclear chemical-shift correlation experiments may also be modulated in similar fashion, as recently suggested by Freeman (18) and Bax (21).
Thermal Conductivity: XII, Temperature Dependence of Conductivity for Single-Phase Ceramics

Theoretical relationships and experimental data concerning thermal conductivity for a number of oxide materials have been compared over a wide temperature range. Deviations from the basic proportionality between k and 1/T are caused by radiant-energy transmission, a high Debye temperature, a low mean free path of the thermoelastic waves, porosity, and in a few cases electronic conductivity. Extrapolation of thermal conductivity data to high temperatures is not reliable.
Molecular Epidemiology of Escherichia coli Sequence Type 131 and Its H30 and H30-Rx Subclones among Extended-Spectrum-β-Lactamase-Positive and -Negative E. coli Clinical Isolates from the Chicago Region, 2007 to 2010

We assessed Escherichia coli ST131 and its H30 and H30-Rx subclones for virulence genes, antimicrobial resistance, and extended-spectrum beta-lactamase (ESBL) type. Although both subclones were associated with ESBL production, H30-Rx isolates had higher resistance scores and were associated specifically with CTX-M-15. Three virulence genes (iha, sat, and iutA) were more prevalent among H30 than non-H30 ST131 isolates. Thus, the H30 and H30-Rx subclones are more antimicrobial resistant and have virulence profiles that are distinct from those of non-H30 ST131 isolates.
Ultrastructure of the right ventricle after monocrotaline-induced cor pulmonale in the nonhuman primate (Macaca arctoides).

Abstract The present study is concerned with the ultrastructural changes that occur in the right ventricle of Macaca arctoides monkeys following subcutaneous injection of the pyrrolizidine alkaloid monocrotaline. The monkeys showed right ventricular hypertrophy and congestive heart failure within 7 months following the initial injection of monocrotaline. At sacrifice, all of the monkeys had developed marked dilatation and hypertrophy of the right ventricle. Focal cytolysis involving myocytes, intracellular edema, and fibrosis were observed light microscopically. Ultrastructural changes of the right ventricle included hypertrophy and hyperplasia of the mitochondria, increase in intracellular matrical material, streaming and clumping of the Z-band material, disorganization and degeneration of myofibrils, dilatation of the sacroplasmic reticulum and transverse tubular system, increased number of free and attached ribosomes, and proliferation of intercellular collagen fibers.
Intestinal metabolism of epicholesterol-4-C14☆

Abstract Epicholesterol-4-C 14 (46.1 mg.) was fed in a physiological test meal to lymph-fistula rats and found to be poorly absorbed into the lymph. Free epicholesterol-4-C 14 was identified as the major C 14 sterol in the lymph and feces plus intestinal contents at the end of 6 and 24 hr., and at 6 hr. in the small intestine. No esterified epicholesterol could be found in those areas. A portion of the fed epicholesterol was converted to a saturated digitonin-precipitable sterol (probably dihydrocholesterol) in its transfer from the lumen of the intestine to the lymph. Lymph, small intestine, and feces plus intestinal contents showed the presence of 3β-C 14 sterols at the end of 6 and 24 hr., with the largest amounts of those sterols present at the latter time. Up to 84% of the 3β-C 14 sterols found in the lymph were present in the esterified form, whereas the major portion of the 3β-C 14 sterols in the small intestine and feces plus intestinal contents was present in the free form. Up to 50% of the C 14 sterols present in the intestinal wall at the end of 24 hr. were digitonin precipitable. The transformation of epicholesterol to 3β-sterol probably occurs in the intestinal wall.
High energy-density propulsion—reducing the risk to humans in planetary exploration

Abstract The potential benefits to humankind of space exploration are tremendous. Space is not only the final frontier but is also the next marketplace. The orbital space above Earth offers tremendous opportunities for both strategic assets and commercial development. The critical obstacle retarding the use of the space around the Earth is the lack of low cost access to orbit. Further out, the next giant leap for mankind will be the human exploration of Mars. Almost certainly within the next 30 years, a human crew will brave the isolation, the radiation, and the lack of gravity to walk on and explore the Red planet. Both of these missions will change the outlook and perspective of every human being on the planet. However, these missions are expensive and extremely difficult. Chemical propulsion has demonstrated an inability to achieve orbit cheaply and is a very high-risk option to accomplish the Mars mission. An alternative solution is to develop a high performance propulsion system. Nuclear propulsion has the potential to be such a system. The question will be whether humanity is willing to take on the challenge.
High density lipoprotein decreases β-amyloid toxicity in cortical cell culture

A hallmark of Alzheimer's disease (AD) is the extracellular deposition and accumulation of a 39–43 amino peptide, known as the amyloid beta (Aβ) protein, within the brain. It has been postulated that Aβ may in some way contribute directly to AD pathogenesis. The 4 allele of apolipoprotein E (apoE) i
Contracting Practice in Fixed-Route Transit Service: Case Studies in California

Contracting plays a significant role in U.S. public transit provision, but there is a gap between the majority of quantitative studies that report significant cost savings from contracting and the few qualitative studies that consider the political nature of an agency's decision about contracting. To fill this gap, the authors systematically examined agency decisions about contracting, by interviewing managers and directors at 13 California transit agencies. In interviews with agencies of various sizes and blends of contracted and in-house services, it was found that agencies have responded differently to fiscal pressures and to contracting as a provision strategy. Some have readily adopted contracting to provide all services, while others have used different strategies, such as part-time labor and varying wage scales, to enhance their cost-efficiency. Those responses are a result not just of economic analysis but also of the agency's institutional environment, relationship with its labor union, and the p...
Real-space multiple scattering theory method: Formalism and applications

Different forms of the real-space multiple scattering theory (RS-MST) formalism are compared in order to understand its convergence behavior with respect to truncation in the angular momentum expansions. In particular the so-called “folding method” or (1,n) mode is considered, in which the renormalized t-matrix T of the semi-infinite system has the dimension of n (n > 1) repeating units and the self-consistent equation for T is constructed by adding and contracting one such unit. It has been demonstrated in previous studies of layered structures that the folding method converges rapidly in both angular momentum (L) and site (n) indices and yields accurate results. The convergence behavior is an important factor to be considered in applying the various forms of the RS-MST method to layered structures as well as other systems with extended defects.
Magnetic nanoparticle temperature estimation

The authors present a method of measuring the temperature of magnetic nanoparticles that can be adapted to provide in vivo temperature maps. Many of the minimally invasive therapies that promise to reduce health care costs and improve patient outcomes heat tissue to very specific temperatures to be effective. Measurements are required because physiological cooling, primarily blood flow, makes the temperature difficult to predict a priori. The ratio of the fifth and third harmonics of the magnetization generated by magnetic nanoparticles in a sinusoidal field is used to generate a calibration curve and to subsequently estimate the temperature. The calibration curve is obtained by varying the amplitude of the sinusoidal field. The temperature can then be estimated from any subsequent measurement of the ratio. The accuracy was 0.3 degree K between 20 and 50 degrees C using the current apparatus and half-second measurements. The method is independent of nanoparticle concentration and nanoparticle size distribution.
Adhesion Model for Metallic Rough Surfaces

An improved DMT adhesion model in conjunction with an elastic-plastic contact model is used to study adhesion of contacting metallic rough surfaces. The effects of surface roughness and surface energy of adhesion on the pull-off force and on the significance of the adhesion force are investigated. It is shown that for clean surfaces the adhesion is quite large even for relatively rough surfaces. Adhesion is negligible only for contaminated rough surfaces or at very high external loading.
Increased incidence of central venous catheter–associated bloodstream infections: Possible link to transparent dressing configuration

BACKGROUND/OBJECTIVES: As part of routine surveillance of nosocomial bacteremia, we noted an increase in the hospital-wide rate of catheter-related bloodstream infection (CRBSI) over our baseline of 0.66 per 1000 patient days (ptpd, July 2002–June 2004). We launched an investigation to determine the cause for this increase. Transparent polyurethane dressings are a popular dressing that does not significantly increase the risk of CRBSI. These dressings have been modified to incorporate a woven tape to help adherence to skin. These dressing designs may change infection rates. One of these new dressings was introduced in our dressing kits before this outbreak. METHODS: Examination of case details was used to look for common factors and exposures. After a multidisciplinary review, we implemented stepwise changes in the dressing used for central line care: we changed to a dressing that put the tape on top of, rather than below, the transparent polyurethane. RESULTS: In surveillance of our 280-bed community teaching hospital, we expect no more than six CRBSI a month; we exceeded this threshold in August 2004. The rate peaked with 14 cases in 5718 patient days in September 2004, a rate of 2.45 ptpd (95% confidence interval 1.3-4.1). Cases occurred with several different types of catheters and on different clinical units. Organisms varied, with an increase in the relative contribution of Candida infections. Procedures for insertion and care of central lines were consistent with CDC guidelines. We found no common risk factors for infection, such as total parenteral nutrition, in a majority of cases. Examination of the epidemiology curve showed an increase that corresponded to the introduction of a new central line dressing. Changing to more frequent dressing changes did not stop the outbreak. Replacing the dressing with a new type of dressing resulted in the rates falling toward baseline (1.3 ptpd, CI 0.51-2.6, in December 2004), even with a return to 7-day dressing change intervals. Compliance was incomplete; surveillance continues following the removal of old dressing. CONCLUSION: Shortly after implementing a tape-reinforced transparent dressing, we detected a fourfold increase in the incidence of CRBSI. By changing dressings to a transparent dressing with a different design, we saw a return in our rate of infection to baseline. This suggests that the presence of woven tape under a transparent dressing may increase the rate of CRBSI.
In vitro effects of hyperlipoproteinemic sera on human endothelium: Inhibition of endothelial cell migration by familial hypercholesterolemic sera

Abstract Since hyperlipoproteinemia is associated with an increased risk of atherosclerosis we have evaluated the effects of sera of different hyperlipoproteinemic clinical patterns on human endothelial cells in vitro. Cultured human umbilical vein endothelial cells were treated with sera from 2 patients homozygous for familial hypercholesterolemia and 4 patients heterozygous for that disorder. Familial hypercholesterolemic sera inhibited endothelial cell migration by 50% during a 72 hour incubation (p