cssi/SciSciGPT-SciSciNet huggingface dataset:
In vitro ictogenesis is stochastic at the single neuron level.

Seizure initiation is the least understood and most disabling element of epilepsy. Studies of ictogenesis require high speed recordings at cellular resolution in the area of seizure onset. However, in vivo seizure onset areas can't be determined at the level of resolution necessary to enable such studies. To circumvent these challenges, we used novel GCaMP7-based calcium imaging in the organotypic hippocampal slice culture model of post-traumatic epilepsy in mice. Organotypic hippocampal slice cultures generate spontaneous, recurrent seizures in a preparation in which it is feasible to image the activity of the entire network (with no unseen inputs existing). Chronic calcium imaging of the entire hippocampal network, with paired electrophysiology, revealed 3 patterns of seizure onset: low amplitude fast activity, sentinel spike, and spike burst + low amplitude fast activity onset. These patterns recapitulate common features of human seizure onset, including low voltage fast activity and spike discharges. Weeks-long imaging of seizure activity showed a characteristic evolution in onset type and a refinement of the seizure onset zone. Longitudinal tracking of individual neurons revealed that seizure onset is stochastic at the single neuron level, suggesting that seizure initiation activates neurons in non-stereotyped sequences seizure to seizure. This study demonstrates for the first time that transitions to seizure are not initiated by a small number of neuronal "bad actors" (such as overly connected hub cells), but rather by network changes which enable the onset of pathology among a large populations of neurons.
US Imperialist Censuses

Starting in 1899, the United States fielded interventionist censuses in Puerto Rico, following its annexation in 1898. US officials intended to revamp the island’s institutions and Americanize Puerto Ricans. Censuses factored into these efforts. The 1899 US census included White, Black, and mixed-race categories. The 1930 census merged the Black and Mulatto categories into “Colored,” a scheme used through the 1950 census. In addition to reducing the number of categories, the US census officials tried to introduce a narrower definition of whiteness that would have excluded most Puerto Ricans. Although the US definitions should have produced a “blackening” of the census, Puerto Ricans subverted the official classifications. This “whitening” trend, most pronounced from 1899–1920, continued through the 1950 census. Notably, everyday understandings of race coexisted with the more restrictive official ones, and the official ones never replaced the fluid, multiple ones used in everyday life. Ultimately, the United States census dropped the race categories from the 1960 through 1990. Therefore, the strong US state could not successfully deploy transformative census categories.
Component analysis algorithms for fast multi-tracer PET signal-separation

95 Objectives Rapid multi-tracer PET can image 2-3 tracers in a single scan to characterize multiple aspects of physiology and function. Dynamic imaging with staggered injections is used, and kinetic constraints are applied to recover individual-tracer signals from multi-tracer datasets. The kinetic constraints are often imposed using multi-tracer compartment modeling. While effective, such algorithms are slow, involve multidimensional nonlinear fits, and require knowledge of the arterial input function for each tracer. This work proposes component-analysis based algorithms for rapid multi-tracer PET signal-separation designed to overcome these limitations. Methods Linear sets of temporal basis functions for each tracers’ allowed kinetic behavior were formed from principal component analysis (PCA) of population time-activity curves combining simulated time-activity curves with measured image components. The resulting linear systems were orthogonal intra-tracer but non-orthogonal between tracers. The multi-tracer signal-separation algorithm first performs linear weighted-least squares fits to these bases for each image voxel. The fitted time-activity curves for each voxel are then used to estimate the proportional contribution of each tracer to each timepoint of the 4D multi-tracer image according to linear mixture analysis. Each voxel of the multi-tracer input image is then separated to form individual-tracer images, preserving the total sum at each point. Results The PCA-based algorithm was evaluated for several tracer combinations using both simulations and clinically acquired images in patients with primary brain tumors (18F-FDG, 18F-FLT, and 11C-acetate). Single-scan dual-state rest+stress myocardial perfusion images were also tested (13N-ammonia). Signal-separation performance was similar to that for full multi-tracer compartment modeling in a fraction of the time, providing voxelwise image separation in just a few seconds CPU time. Conclusions The proposed component-analysis algorithm for multi-tracer PET signal-separation provides fast and robust voxel-by-voxel separation of multi-tracer images. Research Support R01 CA135556
Effective instructional leadership: Teachers’ perspectives on how principals promote teaching and learning in schools

Few studies have directly examined teachers’ perspectives on principals’ everyday instructional leadership characteristics and the impacts of those characteristics on teachers. In this study, over 800 American teachers responded to an open‐ended questionnaire by identifying and describing characteristics of principals that enhanced their classroom instruction and what impacts those characteristics had on them. The data revealed two themes (and 11 strategies) of effective instructional leadership: talking with teachers to promote reflection and promoting professional growth.
Detection and Incidence of Specific Species of Spoilage Bacteria on Fish I. Methodology

Abstract The ability of Pseudomonas putrefaciens to form H2S was found to serve as a singularly useful criterion of identity for this species and was used to directly enumerate the organism from haddock fillets by the use of pour plates of Peptone-Iron Agar. Subsurface colonies appear intensely black, whereas surface colonies are black or gray. A highly sensitive soft-agar-gelatin overlay technique has been found useful for directly determining the numbers of weakly and strongly proteolytic organisms from fish tissue.
Endovascular Approaches to Acute Stroke

Stroke remains the third most common cause of death in industrialized nations, after myocardial infarction and cancer, and the single most common reason for permanent disability [1].
Studies on the adrenocorticotropic hormone-activated adenyl cyclase of a functional adrenal tumor.

An adrenocorticotropic hormone (ACTH)-sensitive, steroid-producing mouse adrenal tumor was homogenized and fractionated by differential centrifugation. The adenyl cyclase activity that was stimulated by ACTH and by fluoride was purified 10- to 20-fold and localized to particulate fractions. The enzyme activity was not affected by several other polypeptide hormones, by epinephrine, or by prostaglandin PGE1. The ACTH-induced increase in adenyl cyclase activity was maximal at pH 7.4 to pH 7.7. The optimal Mg2+:ATP ratio was 1 to 1.5. Enzyme activity in the presence of ACTH was decreased by Ca2+, Na+, K+, and propranolol. Other nucleotides at equimolar concentrations to ATP also decreased the ACTH effect to a variable extent; dATP was the most effective inhibitor.
Linear-Congruence Constructions of Low-Density Parity-Check Codes

Low-Density Parity-Check codes (LDPCC) with Iterative Belief Propagation (Message Passing) decoding are attractive alternatives to Turbo codes. LDPCC previously discussed in the literature have involved matrices constructed using random techniques. In this paper, we discuss construction techniques for LDPCC involving multiple permutation matrices, each specified by a linear congruence. Construction options depend on the size of the parity-check matrix and the rate of the code. We relate desirable properties of the code to the parameters defining the linear congruences specifying the permutation matrices used to construct the code. For example, codes with few or no 4-cycles can be readily constructed. We summarize the construction options and describe selection processes for the parameters of the congruences. We then provide performance results for regular parity-check matrices constructed by random and the linear-congruence techniques for rate 1/2 transmit block-size 980 and rate 4/7 transmit block-size 847 codes. We introduce a symmetric channel model for decoding with the iterative belief propagation algorithm and describe its use as a heuristic for deciding whether a code is likely better or worse than most codes of the given rate and block size.
Child Poverty in the American States: The Impact of Welfare Reform, Economics, and Demographics

This article identifies the predictors of child poverty rates at the state level before and after the adoption and implementation of the Personal Responsibility and Work Opportunity Reconciliation Act of 1996. The analysis shows that the most important state-level factors that influence child poverty rates are demographics, the health and viability of the state economy, and often the generosity, inclusiveness, and quality of state welfare programs. States with large numbers of black citizens, and those that score highest on infant mortality, teen births, births to unmarried women, children living with a parent without a high school degree, and children living with a single parent have the highest rates of child poverty. Child poverty rates are lowest in states that suffer less unemployment, and in wealthier states. States that score higher on per capita personal income, tax revenues, and taxable resources have lower child poverty rates. While specific “tough” welfare policies adopted by some states seem to have no impact on child poverty rates, we tested for the first time a sophisticated measure of the overall quality of state welfare programs. The analysis reveals that the global quality of a state's welfare programs is often an independent predictor of child poverty. States with the most generous, inclusive, and supportive welfare programs have done the best job of lowering and containing child poverty.
A statistical model of turbulence in two-dimensional mixing layers

A statistical model of turbulence in fully developed two-dimensional incompressible turbulent mixing layers is proposed. The development of this model is largely motivated by the recent experimental observations of Brown and Roshko (1974). The model is based on the proposition that the turbulence of a fully developed two-dimensional incompressible mixing layer is in a state of quasi-equilibrium. The model is used to predict the second-order turbulence statistics of the flow including single-point turbulent Reynolds stress distribution, intensity of turbulent velocity components, rms turbulent pressure fluctuations, power spectra and two-point space-time correlation functions. It is shown that numerical results compare favorably with available experimental measurements.
Detection of Fungi and Other Pathogens in Immunocompromised Patients by Bronchoalveolar Lavage in an Area Endemic for Coccidioidomycosis

Bronchoalveolar lavage (BAL) was performed in 51 adult immunocompromised patients (30 acquired immunodeficiency syndrome [AIDS] and 21 non-AIDS) as part of an extensive diagnostic evaluation for diffuse pulmonary infiltrates. Because multiple episodes occurred in several patients, a total of 60 BALs were performed. A diagnosis of fungal pneumonia was eventually made in 12 patients (24 percent). The organism was identified in BALs from seven of the 12, including five of seven cases of coccidioidomycosis, one of two cases of aspergillosis, and one of three cases of cryptococcosis. Among the AIDS patients, only one case of coccidioidomycosis was diagnosed, whereas six such diagnoses were made from the 25 BALs performed on the 21 non-AIDS patients. This suggests that coccidioidomycosis is not as frequent an infection in AIDS patients in this endemic area as has been suggested previously. Candida-like organisms were identified in 23 BALs, but in no case were they clinically pathogenic. Their presence correlated with oral candidiasis (p = 0.01). Twenty-seven of 29 episodes related to Pneumocystis carinii were identified by Papanicolaou-stained cytocentrifuged BAL preparations, all but two of which were in AIDS patients. In addition, BALs detected six episodes of bacterial pneumonia and three of five cases of radiation pneumonitis. Overall, the diagnostic sensitivity of BAL was 52 of 60 or 87 percent. While examination of induced sputum for the presence of Pneumocystis may eliminate the need for bronchoscopy in some AIDS patients, BAL remains an excellent diagnostic procedure in the immunocompromised patient without AIDS.
Yolk sac tumor of the ovary in a young girl with tuberous sclerosis: A case report and review of the literature.

Tuberous sclerosis (TS) is a relatively common neurocutaneous genetic disorder affecting 1 in 10,000 people and has a spectrum of manifestations due to incomplete penetrance (Crino et al., 2006). Common features include cognitive and behavioral problems, seizures, hypomelanotic “ash-leaf” spots, facial angiofibromas, hamartomatous and choristomatous tumors. Lesions commonly associated with TS include subependymal neural tubers, renal angiomyolipomas (rAMLs) and cardiac rhabdomyomas (Crino et al., 2006).
Time-dependent rate coefficients for diffusion-influenced reactions with centrosymmetric potentials.

Simple closed-form expressions are presented for the time-dependent rate coefficients of diffusion-influenced reactions in the presence of spherically symmetric potentials. For diffusion-controlled contact reactions, our expression reproduces the first two terms in both the short- and long-time expansions of the rate coefficient. At intermediate times, agreement with numerical results for the Debye-Huckel potential is found to be within a few percent for a wide range of parameters. For diffusion-influenced contact reactions (described by the radiation boundary condition), the agreement is even better. When the reactivity depends on the distance between the reactants (e.g., exponentially), our analytic result is less accurate, because it reproduces the two terms in the long-time expansion only to the linear order of the reciprocal of the diffusion coefficient. Our results should prove useful in the analysis of experimental data for diffusion-influenced reactions with centrosymmetric interaction potentials.
Mechanical stresses in (sub)monolayer epitaxial films

We have studied stresses in thin Ge growing on Si(001), in situ and in real time, with submonolayer sensitivity. As a result of the 4.3% lattice mismatch, Ge films develop a compressive stress in the 2D growth regime, which saturates when 3D growth sets in. These measurements give new insight in the interatomic forces that play a dominant role in establishing growth mode and the generation of defects, and provide a new test for state-of-the-art total-energy calculations.
PROPAGATION OF CYTOSOLIC CALCIUM WAVES INTO THE NUCLEI OF HEPATOCYTES

Abstract The temporal and spatial organization of [Ca 2+ ] changes within the nucleus of Fura-2 loaded hepatocytes maintained in primary culture has been investigated. Vasopressin stimulation induced oscillatory waves of cytosolic free [Ca 2+ ] increase, which propagated freely through the nuclear region. Based on the amplitude of the Fura-2 signals from this region, the morphology of the hepatocyte nucleus and the rapid penetration of the nucleus by injected Fura-2, it can be concluded that the nuclear Ca 2+ responses reflect changes occurring within the nucleoplasm. Intranuclear Ca 2+ increases occurred as waves that appear to be directed by the Ca 2+ waves passing through the surrounding cytoplasm. The apparent velocity of Ca 2+ waves was higher in the nucleoplasm than in the cytoplasm (19.5 ± 2.9 versus 11.0 ± 1.1 μm/s). The nucleoplasm does not contain vesicular Ca 2+ stores that might be released by Ins(1,4,5)P 3 . However, the nuclear envelope functions as a Ca 2+ store that is sensitive to mobilization by Ins(1,4,5)P 3 . We conclude that the [Ca 2+ ] in the nucleoplasm of the hepatocyte is close to equilibrium with the cytosolic [Ca 2+ ] and that oscillatory waves of cytosolic [Ca 2+ ] are closely paralleled by similar [Ca 2+ ] changes in the nucleoplasm. The nuclear envelope is a component of the intracellular Ins(1,4,5)P 3 -sensitive Ca 2+ storage pool and may serve as a reservoir for [Ca 2+ ] elevations within the nucleus.
The Health of Older Mexican Americans in the Long Run.

Objectives. We compared risk for several medical illnesses between immigrant and US-born older Mexican Americans to determine the relationship between functional health and years of US residency among immigrants.Methods. Cross-sectional, multistage probability sample data for 3050 Mexican Americans aged 65 years or older from 5 US southwestern states were analyzed. Self-rated health, medical illnesses, and functional measures were examined in multivariate regression models that included nativity and years of US residency as key predictors.Results. Self-rated health and medical illnesses of immigrant and US-born groups did not differ significantly. Immigrants with longer US residency had significantly higher cognitive functioning scores and fewer problems with functional activities after adjustment for predisposing and medical need factors.Conclusions. Among older Mexican Americans, immigrant health advantages over their US-born counterparts were not apparent. Immigrants had better health functioning with ...
Enamel Silicon and Fluoride Relationships Demonstrating a Surface Silicon Effect that Facilitates Fluoride Uptake

The silicon and fluoride content and the effect of increased enamel silicon concentration on fluoride uptake in enamel were determined. There is an apparent linear association between silicon and fluoride in enamel. Furthermore, a I μmole increase of silicon acts to enhance topical fluoride uptake by 29 ppm.
Washout ratios of nitrate, non-sea-salt sulfate and sea-salt on Virginia key, Florida and on American Samoa

Abstract On Virginia Key, Miami, Florida, 257 rainwater samples were collected on a event basis from May 1982 to April 1985. At the same site, 171 aerosol samples were collected throughout 1984. All of these samples were analyzed for nitrate, non-sea-salt (NSS) sulfate and sodium to assess the temporal variations in the concentrations and to determine the washout ratios of each of the constituents. The annual volume-weighted mean concentrations in rainwater are: nitrate—0.51 μg ml −1 ; NSS sulfate—0.74 μg ml −1 ; Na—1.93 μg ml −1 . Only sodium exhibited a significant seasonal cycle; its concentrations were markedly higher during the winter. In aerosols, the mean concentrations are: nitrate—1.9 μg m −3 ; NSS sulfate—2.8 μg m 3 ; Na—3.7 μg m −3 . Nitrate and NSS sulfate exhibit consistent seasonal cycles with concentrations being significantly higher during the winter and spring. We estimate that wet deposition accounts for the majority of the total fluxes of each constituent: 80% for nitrate, 95 % for NSS sulfate, and 67% for Na. Annual washout ratios at Virginia Key arc similar for nitrate and NSS sulfate, 330 and 290, respectively. That for Na is about a factor of two higher, 550. Comparable long-term ratios were calculated for American Samoa based on aerosol data from the SEAREX program and rainwater data from the National Atmospheric Deposition Program: 270 for nitrate, 420 for NSS sulfate, and 520 for Na. The comparability of the Virginia Key and Samoa results suggest that these ratios may be applicable over a wide area of the world ocean. Estimates from nonconcurrent data for the washout ratios at Bermuda were factors of two to four higher. Regression equations for washout ratio vs event rainfall ( log W = log a + b log R ) at Virginia Key were essentially the same for all three constituents with ‘ a ’ ranging from 1100 to 1300 and ‘ b ’ ranging from −0.26 to −0.29. The coefficients for American Samoa were markedly different: ‘ a ’ ranged from 2900 to 3600 and ‘ b ’ ranged from −0.51 to −0.56.
Ethics of re-hearsing procedures on a corpse

You are the attending surgeon of a homeless pedestrian who sustained multiple injuries when struck by a car. He died soon after being brought to the emergency department. It is late in the evening. A first-year resident and a medical student have been helping with the failed attempt at resuscitation. The emergency department is empty, except for your case. A central line kit lies on the bed, opened but not used. The junior resident asks your permission for herself and the student to practice the technique of subclavian cauterization and tracheal intubation on the fresh cadaver to get a "feel" for the procedures. There is no medical simulation for these procedures at your medical center. The best ethical response is: A. Tell them to go ahead and practice. B. They can only practice intubation because it leaves no external wounds. C. You should supervise them yourself to assure educational benefit. D. They should wait until you get permission from the medical examiner. E. The present case is not appropriate for educational purposes.
Fluorescence quenching in phenylalanine and model compounds.

Abstract— The effects of the carboxylic and amino groups in their neutral and charged forms on the absorption and emission properties of phenylalanine are analyzed with the help of model compounds containing either substituent. Fluorescence yields of phenylalanine and model compounds were measured as a function of pH. Fluorescence quenching occurs in going from COO- to COOH and from NH3+ to NH2. Lowering the ionization potential of the phenyl group by substitution increases the quenching effect. This provides more evidence that an intramolecular charge-transfer mechanism may be responsible for intersystem-crossing rate enhancement and fluorescence quenching in phenylalanine and model compounds.
Quantized Chaotic Dynamics and Non-commutative KS Entropy

Abstract We study the quantization of two examples of classically chaotic dynamics, the Anosov dynamics of “cat maps” on a two dimensional torus, and the dynamics of baker's maps. Each of these dynamics is implemented as a discrete group of automorphisms of a von Neumann algebra of functions on a quantized torus. We compute the non-commutative generalization of the Kolmogorov–Sinai entropy, namely the Connes–Stormer entropy, of the generator of this group, and find that its value is equal to the classical value. This can be interpreted as a sign of persistence of chaotic behavior in a dynamical system under quantization.
Keepers of the Sacred Chants: The Poetics of Ritual Power In an Amazonian Society

Keepers of the Sacred Chants: The Poetics of Ritual Power In an Amazonian Society. Jonathan D. Hill. Tucson: University of Arizona Press, 1993. xix. 245 pp., index, bibliography, notes, glossary, figures.
Perioperative Patient Safety and Procedural Sedation

The use of sedation administered by nonanesthesia providers has increased exponentially over the past decade. Moderate sedation is safe but has potential adverse reactions such as hypoxemia, apnea, hypotension, airway obstruction, and cardiopulmonary arrest. Patient safety is the responsibility of every person on the perioperative team and relies on an effective sedation delivery system to keep the patient from harm. Performing safe and effective sedation involves several aspects of sedation, including the persons administering the sedation, the educational processes involved, the environment in which the sedation is conducted, patient-specific information processes, and guidelines and protocols of the institution. Future areas of research in clinical studies include safety and efficacy studies, applications of new technology, and procedural sedation and analgesia adjuncts.
A hierarchical analysis of vegetation on a Mojave Desert landscape, USA

Abstract To examine four elements of the hierarchical structure of desert communities, we analyzed plant species composition and 13 environmental variables at 126 sites within a 755 000-ha Mojave Desert landscape, southwestern USA. By a coarse, six-group level (out of 17 groups) in cluster analysis, four generalized community types emerged: widespread, low-elevation communities with Larrea tridentata or Ambrosia dumosa ; communities on unique soils (e.g., gypsum) indicated by Atriplex spp.; higher elevation/rugged terrain communities including Coleogyne ramosissima ; and disturbance-associated communities such as Bebbia juncea - Hymenoclea salsola . Based on indicator species analysis (ISA), there was no clear level of the community classification that optimized discriminating among communities, because each of four measures of ISA peaked at different hierarchical levels. Three general types of indicator species were identified based on whether their value for discriminating among communities peaked at coarse (e.g., L. tridentata ), intermediate ( Atriplex hymenelytra ), or fine ( Krameria grayi ) levels of the community hierarchy. Environmental variables differed in their relationships to the hierarchy, with some (e.g., pH) not differing among communities at any level and others, such as rooting depth, differing among communities at multiple levels. Hierarchical analytical techniques can help identify structural patterns within arid land plant communities, species distributions, and vegetation–environment relationships.
Assessment of anger expression in children: The pediatric anger expression scale

Abstract Anger expression stylistics have been the focus of increasing attention in research on cadiovascular diseases. Research with adults has lead to increasingly complex models of anger response stylistics. The present study describes further research on the Pediatric Anger Expression Scale (PAES). The PAES is a brief, objective, self-rating instrument. Factor analyses produced four factors: Anger—out; Anger—control; Anger—reflection; and Anger—suppression. This factor structure confirms the complexity of anger expression stylistics in children. Males seem more prone to openly express their anger, while females appear to be more likely to respond to angry feelings with more rational responses. Anger—out was positively correlated with self-ratings of anger, anxiety, and Type A behavior pattern. The other PAES subscales were negatively correlated with these same measures and with teacher ratings of Type A. Research being conducted to further examine anger expression stylistics in children is noted.
Stimulation of malic enzyme formation in hepatocyte culture by metabolites: evidence favoring a nonglycolytic metabolite as the proximate induction signal.

Abstract Recent studies have shown that the addition of increasing concentrations of glucose to the medium of primary adult rat hepatocyte cultures results in the progressive induction of malic enzyme. We have undertaken experiments to determine (1) whether metabolism of glucose was an essential prerequisite for such induction, and (2) whether a specific glycolytic intermediate could be shown to constitute the proximate carbohydrate signal triggering such induction. In line with these objectives we investigated the ability of various sugars and glycolytic metabolites to induce malic enzyme in this system and assessed the influence of insulin, glucagon, and thyroid hormone (triiodothyronine, T 3 ) on this process. Our results show that only those sugars capable of entering the cell and being metabolized induce malic enzyme (glucose, fructose, and galactose). The nonmetabolizable sugars 3-O-methylglucose and 2-deoxyglucose are ineffective. Incubation with 20 mmol/L lactate, pyruvate, dihydroxyacetone, or glycerol resulted in malic enzyme induction, whereas incubation with acetate, citrate, and α-ketoisocaproate was without effect. The induction by all sugars and metabolites required presence of insulin. As previously reported for glucose, addition of T 3 , under all metabolic conditions, resulted in a constant 3.6-fold increase in the rate of malic enzyme induction and further supports the proposal that T 3 acts to multiply the effect of a common carbohydrate-generated signal. Glucagon administration led to a dose-dependent inhibition of the carbohydrate effect with a half-maximal effect and maximal effect at 2 and 100 nmol/L, respectively. None of the glycolytic metabolites tested could reverse the glucagon inhibition completely. Our results indicate that metabolism of glucose is essential for induction of malic enzyme and are most consistent with the view that the signal arises from the metabolism of pyruvate at a step before the formation of cytsolic acetyl-CoA. Since these processes are mitochondrial in location, it appears likely that this organelle is the site of origin of the inducing signal. Of some interest in this connection was the finding that dichloroacetate led to a major induction of malic enzyme, even in the absence of insulin and in the presence of glucagon. The ability of dichloroacetate to bypass the glucagon block thus further supports a nonglycolytic origin of the inducing signal.
Band structure and magnetotransport of a two-dimensional electron gas in the presence of spin-orbit interaction

The band structure and magnetotransport of a two-dimensional electron gas (2DEG), in the presence of the Rashba (RSOI) and Dresselhaus (DSOI) terms of the spin-orbit interaction and of a perpendicular magnetic field, is investigated. Exact and approximate analytical expressions for the band structure are obtained quantum mechanically and used to calculate the density of states (DOS) and the longitudinal magnetoresitivity assuming a Gaussian type of level broadening. The interplay between the Zeeman coupling and the two terms of the SOI is discussed. If the strengths $\ensuremath{\alpha}$ and $\ensuremath{\beta}$, of the RSOI and DSOI, respectively, are equal and the $g$ factor vanishes, the two spin states are degenerate and a shifted Landau-level structure appears in agreement with recent semiclassical results. With the increase of the difference $\ensuremath{\alpha}\text{\ensuremath{-}}\ensuremath{\beta}$, a beating pattern of the DOS and of the Shubnikov-de Haas oscillations appears distinctly different from that occurring when one of these strengths vanishes. For $\ensuremath{\alpha}⪢\ensuremath{\beta}$ or $\ensuremath{\alpha}⪡\ensuremath{\beta}$ the peaks in one wrap of the beating pattern occur at even filling factors of the 2DEG while in the next wrap they occur at odd filling factors. For $\ensuremath{\alpha}\ensuremath{\approx}\ensuremath{\beta}$ this transition occurs only if the spin splitting is larger than half the Landau energy.
Four failure regions of a nickel-based metallic glass

Analyse fractographique de la rupture de l'alliage Ni 92,24 Si 4,5 B 3,2 C 0,06 soumis a une flexion in situ. Quatre regions de rupture sont distinguees: la region de glissement, la region de rupture a «diagramme de veines», la region de rupture rapide, et la region de rupture catastrophique. Etude de ces regions
Dynamic shear stimulation of bovine cartilage biosynthesis of proteoglycan 4.

Objective The boundary lubrication function of articular cartilage is mediated in part by proteoglycan 4 (PRG4) molecules at the articular surface and in synovial fluid. The objective of this study was to determine the effects of dynamic shear stimulation on PRG4 biosynthesis by bovine cartilage explants. Methods Cartilage disks with intact articular surfaces were harvested from immature bovines. Some disks were subjected to 24 hours (day 1) of loading, consisting of a step load of 20% static compression either alone or with superimposed dynamic shear (3% amplitude and 0.1 Hz), while other disks were cultured free-swelling as controls. After the 24-hour loading period, disks were terminated or were further incubated for up to 72 hours (days 2–4) in free-swelling culture to assess chondrocyte responses to, and following, unloading. PRG4 products secreted into culture medium were quantified by enzyme-linked immunosorbent assay and characterized by Western blotting. Chondrocytes expressing PRG4 were localized by immunohistochemistry, and depth-associated variations in chondrocyte PRG4 expression were quantified by image analysis. Results Dynamic shear stimulation increased PRG4 secretion to 3–4 times that of unloaded controls and statically compressed samples. Sheared cartilage secreted more PRG4 of 345 kd relative to smaller molecular weight species, as compared with unloaded controls. Immunohistochemistry revealed that shear stimulation also increased the total number of cells expressing PRG4 by inducing expression by cells at a depth of 200–400 μm. Conclusion The paradigm that certain mechanical stimuli up-regulate biosynthesis in cartilage appears operative not only for load-bearing matrix constituents, but also for PRG4 molecules that mediate lubrication.
Introduction and expression of the 400 kilobase precursor amyloid protein gene in transgenic mice

Overexpression of the gene encoding the β–amyloid precursor protein (APP) may have a key role in the pathogenesis of both Alzheimer's disease (AD) and Down Syndrome (DS). We have therefore introduced a 650 kilobase (kb) yeast artificial chromosome (YAC) that contains the entire, unrearranged 400 kb human APP gene into mouse embryonic stem (ES) cells by lipid–mediated transfection. ES lines were generated that contain a stably integrated, unrearranged human APP gene. Moreover, we demonstrate germ line transmission of the APP YAC in transgenic mice and expression of human APP mRNA and protein at levels comparable to endogenous APP. This transgenic strategy may prove invaluable for the development of mouse models for AD and DS.
Estimation in two sample randomly truncated scale model

Abstract This paper studies a class of Cramer–von Mises type minimum distance estimators of the scale parameter in the two sample randomly left truncated scale models. The proposed class of estimators includes an analogue of the well-known Hodges–Lehmann estimator. The paper proves the asymptotic normality of these estimators under mild conditions. It also contains a real data application and a simulation study making a comparison of some of the estimators in the class with the ratio of the two means.
Surface energy and solute strain energy effects in surface segregation

Abstract Previous models of surface segregation have generally been based on the assumption that a decrease in surface free energy constitutes the predominant driving force for the phenomenon. In contrast, grain boundary segregation models have been founded on the postulate that the major driving force for that phenomenon is the reduction in lattice strain energy which accompanies the transfer of misfitting solute atoms from the lattice to the boundary. These two concepts have been combined here into a single unified formalism of surface segregation. In addition, the temperature dependence of surface composition of both nickel-rich and gold-rich nickelgold alloys has been measured by Auger electron spectroscopy. Comparisons of the predictions of the combined formalism with the experimental results show excellent agreement between measured and calculated heats of adsorption (segregation). Furthermore, the present formalism provides estimates of the entropies of adsorption which can be used to explain apparent incompatibilities between the behavior of gold-rich and nickel-rich alloys.
Studies of the relationship between coal petrology and grinding properties

Abstract The maceral and microlithotype composition of selected coals has been investigated with respect to the grinding properties, specifically Hardgrove grindability index (HGI), of the coals. The study expands upon previous investigations of HGI and coal petrology by adding the dimension of the amount and composition of the microlithotypes. Coal samples, both lithotypes and whole channels, were selected from restricted rank ranges based on vitrinite maximum reflectance: 0.75–0.80% R max , 0.85–0.90% R max and 0.95–1.00% R max . In this manner, the influence of petrographic composition can be isolated from the influence of rank. Previous investigations of high volatile bituminous coals demonstrated that, while rank is an important factor in coal grindability, the amount of liptinite and liptinite-rich microlithotypes is a more influential factor. In this study, we provide further quantitative evidence for the influence of microlithotypes on HGI and, ultimately, on pulverizer performance.
Omniscience and deliberation

To sum up, we have argued that if deliberation is incompatible with (fore)knowing what one is going to do at the time of the deliberation, then God cannot deliberate. However, this thesis cannot be used to show either that God cannot act intentionally or that human persons cannot deliberate. Further, we have suggested that though omniscience is incompatible with deliberation, it is not incompatible with either some speculation or knowing something on the grounds of inference. Funding for writing this article was provided by the National Endowment for the Humanities through its institute on human action conducted by Robert Audi at the University of Nebraska.
New Reconstructive Technologies in Skull Base Surgery: Role of Titanium Mesh and Porous Polyethylene

Objective To report on 8 years of experience with 156 titanium mesh and porous polyethylene implants used for craniofacial reconstruction after skull base surgery in 100 patients. Design Cohort study with a mean follow-up of 5 years. Setting Population based. Patients A consecutive sample of 100 patients treated for skull base tumors or craniofacial trauma who underwent reconstruction with 156 3-dimensional titanium mesh and/or porous polyethylene implants. A retrospective review of the Skull Base Program database, along with photographic and imaging documentation, was undertaken. Main Outcome Measures Rate of complications as well as the degree of functional and esthetic reconstruction. Intervention The reconstructive technique focused primarily on the substitution of removed craniofacial skeleton for oncologic reasons or soft tissue defects. Results After completion of follow-up (mean, 5 years), all 100 patients remained healed except for 7 patients (7%) with 8 implants (5%). Overall, excellent craniofacial symmetry and stability were achieved with both types of implants. Conclusions Immediate craniofacial skeletal reconstruction and soft tissue augmentation is feasible with 3-dimensional titanium mesh and porous polyethylene implants. The reviewed 8-year evolution in the use of these technologies (156 implants in 100 patients) highlights the excellent tolerance of these implants (5% implant complication rate) in 100 patients (7% complication rate). The few encountered complications were judged to be primarily related to the quality of the overlying soft tissue and not to the implants themselves. The advantages of using these implants for immediate 3-dimensional skeletal and soft tissue substitution, including availability, easy contouring, stability, primary healing, and tolerance of adjuvant therapy, translate to an improved function and esthetic appearance, with a better quality of life for patients.
Robotics: Challenges to present-day technology: Robots must be produced in great numbers with more advanced capabilities, and we must lose our fear that they are taking over our jobs

Robots have received a great deal of publicity lately. The enormous influx of foreign cars manufactured in part by robots has aroused the awareness of the press and many politicians to the fact that robots can have a profound effect on industrial productivity. Many people today believe that the robot revolution is well under way, that factories are full of armies of these highly intelligent “steel-collar workers,” and that human workers are being displaced in droves. The facts are quite different.
Analyses of HLA-DQ Alleles in Recurrent Spontaneous Abortion (RSA) Couples

PROBLEM: The influence of HLA sharing on pregnancy outcome is controversial. In renal transplantation, HLA-DQB1 donor-recipient mismatches have been shown beneficial for long-term transplant success. Since pregnancy is defined as Nature's allograft, we investigated the relevance of HLA-DQ mismatching in normal reproducing couples compared to couples experiencing RSA. METHOD: Unexplained RSA couples referred to our laboratory for immunological testing were classified by immunological findings and obstetrical history. Primary RSA couples shared ≥ 2 HLA-A, B, or DR antigens, had no cytotoxic anti-paternal antibodies, and no gestation beyond 20 weeks. Secondary RSA couples had cytotoxic anti-paternal antibodies and RSA after a live birth. HLA-DQA1 and DQB1 alleles were identified by PCR-SSP. RESULTS: No differences in DQA1 and DQB1 mismatch were observed among RSA patients and controls. DQA1-DQB1 haplotype mismatches were not different among the three groups of couples. CONCLUSIONS: In contrast to renal transplant, HLA-DQ incompatibility did not differ among RSA couples compared with successful reproducing couples.
Triple infection with human immunodeficiency virus, hepatitis C virus, and hepatitis B virus: a clinical challenge.

Triple infection with human immunodeficiency virus, hepatitis C virus, and hepatitis B virus: A clinical challenge
Generation of nitrotyrosine precedes activation of metalloproteinase in myocardium of hyperhomocysteinemic rats

The hypothesis is that homocysteine decreases endothelial nitric oxide (NO) availability by generating nitrotyrosine. In the absence of NO, and in an attempt to reduce endocardial load by dilatation, the matrix metalloproteinase (MMP) is activated. To address this hypothesis, homocysteine (0.67 mg/ml) was administered in drinking water of Sprague-Dawley rats for 8 weeks. To elicit the reversible effects of homocysteine, homocysteine was removed from the water after 8 weeks. The plasma levels of homocysteine were 2.79 +/- 0.5 microM in control (n = 6), measured by spectrofluorometry. The levels of homocysteine increased to 22 +/- 1.3 and 17 +/- 2.8 microM following 4 (n = 6) and 8 (n = 6) weeks of homocysteine treatment, respectively. The level of homocysteine decreased to 5.8 +/- 1.0 microM (n = 6) when homocysteine was removed from the drinking water. The mean arterial pressure (MAP) of control rats was 108 +/- 10 mm Hg and increased to 128 +/- 2 and 130 +/- 3 mm Hg following 4 and 8 weeks of homocysteine treatment, respectively. When homocysteine was removed from the drinking water, the MAP was decreased to 118 +/- 3 mm Hg. Left ventricle (LV) parameters were measured by a catheter in the LV through right common carotid artery in anesthetized rats. The LV tissue was analyzed for MMP activity by zymography. Levels of nitrotyrosine and cardiospecific tissue inhibitor of metalloproteinase-4 (TIMP-4/CIMP) were measured by western blot analysis using the respective antibodies. The specific bands in zymographic gel and western blot were scanned and normalized with beta-actin. The results suggest a continuous increase in nitrotyrosine levels at 4 and 8 weeks after homocysteine administration. The removal of homocysteine did not decrease the levels of nitrotyrosine. The zymographic analysis revealed a temporal increase in MMP-2 activity from 4 to 8 weeks post homocysteine administration. However, removal of homocysteine did not decrease the MMP-2 activity. The cardiac active diastolic function, -dP/dt, was decreased at 4 weeks and stayed depressed up to 12 weeks. The end-diastolic pressure started increasing at 8 weeks; at this point the MMP-2 activity was also increased. The results suggest that in the absence of endothelial NO, and in an attempt to reduce LV load, MMP-2 is activated and CIMP is inactivated, by increasing nitrotyrosine.
Evaluating Risks for Vigabatrin Treatment

Approximately 30 to 40 percent of adults with epilepsy treated chronically with vigabatrin develop concentric visual field constrictions. These deficits are generally mild and asymptomatic, but are usually irreversible, so risks and benefits for vigabatrin treatment must be carefully reviewed. Infantile spasms, a particularly severe form of epilepsy, may respond to vigabatrin; however, some infants treated with the drug develop MRI evidence of possible intramyelinic edema in subcortical structures. This article reviews the benefits of vigabatrin treatment, the risks it poses to the retina and the developing brain, as well as possible subgroups of adults and infants with severe epilepsy for whom treatment may, nevertheless, be warranted.
Fixed prosthodontics and esthetic considerations for the older adult

A new generation of older adults, who are more educated, health-conscious, and economically independent than their predecessors is bringing a fresh perspective and poses unique opportunities and challenges to fixed prosthodontics. Subtle differences in technique, attention to detail, and innovative application of materials and procedures are the main ingredients of successful fixed prosthodontic care for seniors. The goals of fixed prosthodontics for the older adult are fundamentally different from those for a younger population. A practice that enhances the integrity of residual tooth structure while simultaneously creating an environment less prone to dental disease and disability should be emphasized.
Morphology evolution in spinel manganite films deposited from an aqueous solution

Abstract Spinel manganite films were deposited by the spin spray technique at low deposition temperatures ( 1000, agglomeration of small particles was dominant, which suggests that homogeneous nucleation is dominant during deposition. Heterogeneous nucleation was critical to obtain dense films.
Test construction in the 1990s: Recent approaches every psychologist should know.

The article summarizes the current state ofthe art in test construction and contrasts it with previous conceptual models, some of which are wrong or misleading. In particular, new methodologies for item selection and review are presented as well as current thinking on the specification of technical characteristics of tests.
The effect of heat acclimation on maximal urine osmolality in humans

Abstract The purpose of the current study was to determine the effect of 9 days of active heat acclimation on maximal urine osmolality (MUO) in humans. Eight subjects completed 9 days of heat acclimation, which consisted of a daily 90 min exercise session in a heated environmental chamber. Before and following heat acclimation the subjects abstained from drinking fluids for 15 h, and urine samples were collected to measure MUO. The subjects successfully heat acclimated as evidenced by a significant ( P −1 , respectively, which were not significantly different ( P >0.05). Previous studies have shown that prolonged dehydration can increase the MUO in various mammalian species, including humans. In contrast, the results of the current study suggest that 9 days of active heat acclimation, without significant dehydration, does not affect the MUO in humans.