cssi/SciSciGPT-SciSciNet huggingface dataset:
Nervous System: Normal Anatomy and Histology of the CNS

ANATOMY Knowledge of nervous system anatomy is essential for success in surgical neuropathology. Familiarity with native cellular elements will often predict the appearances of diverse tumors within the brain but, perhaps more importantly, recognition of normal or reactive processes will help avoid the pitfall of diagnosing malignancy when, in fact, a nonneoplastic reactive process or even normal tissue is present. Many surgical neuropathology specimens originate in the brain and spinal cord coverings, cranial and spinal nerve roots, blood vessels, and bone and soft tissue surrounding the nervous system; thus recognition of the normal brain is not enough. As with general surgical pathology, knowledge of diseases common to these locations and the ages at which they typically occur is essential. The human brain can be described in many ways. However, for the purpose of surgical neuropathology, this description will emphasize different surgical compartments and cytoarchitectural areas that are especially associated with tumors or other pathological processes (Figure 1.1). The central nervous system (CNS) is often divided into the supratentorial and infratentorial compartments by the dural tentorium, which separates the cerebral hemispheres from the brainstem and cerebellum. The spinal cord, roots , and distalmost cauda equina and filum terminale (Figure 1.2) are often considered separately, especially in view of the paraspinal soft tissue pathology, which can affect the integrity of the spinal cord. Brain tissue is divided into gray and white matter . This distinction may be useful in the differential diagnosis of neoplasms, but is more important in other pathological processes such as infection or neurodegeneration. The surgical neuropathologist is often interested in the relation of a tumor to the ventricles , including the ventricular spaces themselves and their periventricular regions.
Crustal thickness and support of topography on Venus

United States. National Aeronautics and Space Administration (NASA Planetary Geology and Geophysics Program grant)
Health-related quality of life and health behaviors by social and emotional support. Their relevance to psychiatry and medicine.

Social and emotional support is an important construct, which has been associated with a reduced risk of mental illness, physical illness, and mortality. Despite its apparent relevance to health, there have been no recent state or national population-based U.S. studies regarding social and emotional support. In order to better address this issue, we examined health-related quality of life (HRQOL) and health behaviors by level of social and emotional support in community-dwelling adults in the United States and its territories. Data were obtained from the Behavioral Risk Factor Surveillance System, an ongoing, state-based, random digit telephone survey of the noninstitutionalized U.S. population aged ≥18 years. In 2005, one social and emotional support question, four HRQOL questions, two disability questions, one life satisfaction question, and four health behavior questions were administered in the 50 states, the District of Columbia, Puerto Rico, and the U.S. Virgin Islands. An additional five HRQOL questions were administered in two states. An estimated 8.6% of adults reported that they rarely/never received social and emotional support; ranging in value from 4.2% in Minnesota to 12.4% in the U.S. Virgin Islands. As the level of social and emotional support decreased, the prevalence of fair/poor general health, dissatisfaction with life, and disability increased, as did the mean number of days of physical distress, mental distress, activity limitation, depressive symptoms, anxiety symptoms, insufficient sleep, and pain. Moreover, the prevalence of smoking, obesity, physical inactivity, and heavy drinking increased with decreasing level of social and emotional support. Additionally, the mean number of days of vitality slightly decreased with decreasing level of social and emotional support; particularly between those who always/usually received social and emotional support and those who sometimes received support. These findings indicate that the assessment of social and emotional support is highly congruent with the practice of psychiatry. Assessment of social and emotional support, both in psychiatric and medical settings, may identify risk factors germane to adverse health behaviors, and foster interventions designed to improve the mental and physical health of at risk segments of the population.
Protein structure determination using protein threading and sparse NMR data (extended abstract)

It is well known that the NMR method for protein structure determination applies to small proteins and that its effectiveness decreases very rapidly as the molecular weight increases beyond about 30 kD. We have recently developed a method for protein structure determination that can fully utilize partial NMR data as calculation constraints. The core of the method is a threading algorithm that guarantees to find a globally optimal alignment between a query sequence and a template structure, under distance constraints specified by NMR/NOE data. Our preliminary tests have demonstrated that a small number of NMR/NOE distance restraints can significantly improve threading performance in both fold recognition and threading-alignment accuracy, and can possibly extend threading's scope of applicability from structural homologs to structural analogs. An accurate backbone structure generated by NMR-constrained threading can then provide a significant amount of structural information, equivalent to that provided by the NMR method with many NMR/NOE restraints; and hence can greatly reduce the amount of NMR data typically required for accurate structure determination. Our prelimenary study suggest that a small number of NOE restraints may suffice to determine adequately the all-atom structure when those restraints are incorporated in a procedure combining threading, modeling of loops and sidechains, and molecular dynamics simulation. Potentially, this new technique can expand NMR's capability to larger proteins.
An efficient output-sensitive hidden surface removal algorithm and its parallelization

In this paper we present an algorithm for hidden surface removal for a class of polyhedral surfaces which have a property that they can be ordered relatively quickly like the terrain maps. A distinguishing feature of this algorithm is that its running time is sensitive to the actual size of the visible image rather than the total number of intersections in the image plane which can be much larger than the visible image. The time complexity of this algorithm is O((k +n)lognloglogn) where n and k are respectively the input and the output sizes. Thus, in a significant number of situations this will be faster than the worst case optimal algorithms which have running time O(n2) irrespective of the output size (where as the output size k is O(n2) only in the worst case). We also present a parallel algorithm based on a similar approach which runs in time O(log4(n+k)) using O((n + k)/log(n+k)) processors in a CREW PRAM model. All our bounds are obtained using ammortized analysis.
The Economy of Sudan: A Potential Breadbasket of the Arab World?

The Democratic Republic of the Sudan was among the first of nonsovereign territories in Africa to obtain its independence from European political control. Formerly under the joint sovereignty of Britain and Egypt it became independent on January 1, 1956. Since its declaration of independence, Sudan has experienced three major self-proclaimed revolutions, and the format of government has twice changed between parliamentary democracy and military regimes. As of this writing, the current government under General Jaʻafar el-Numayri has been in power longer than any of its predecessors. General Numayri's success in ending the sixteen-year-old civil war between north and south has bolstered his position as head of state. Consequently, this success and at least three other factors have induced the world to pay considerable attention to Sudan.
Selection of optimum affinity tags from a phage-displayed peptide library : Application to immobilized copper(II) affinity chromatography

Immobilized metal affinity chromatography (IMAC) is a versatile tool for the purification of proteins with affinity for immobilized metals. Moreover, this technique has also been used for the separation of proteins that do not exhibit significant metal affinity in the native form, by their fusion to a short metal-binding peptide (a tail), most commonly, a sequence consisting of six adjacent histidine residues (His6). A phage-displayed random hexamer library is used to select for peptides with affinity for immobilized copper. The study follows our previous investigation in which a stringent selection protocol led to the selection of only one copper-binding peptide containing two histidines. The less stringent conditions employed in this work resulted in the selection of a more diverse population of peptides, but again, dominated by peptides containing two histidines (13 out of 19). The prevalence of peptides with two histidines, in contrast to peptides with a higher number of histidines (e.g. His6 or HHHMVH), is explained based on the differences in the pH dependence of their affinity for copper. As discussed, the selected peptides with two histidines will be superior affinity tails than peptides with a higher histidine content (e.g. His6). Moreover, a peptide with a single histidine but with a very high copper affinity, is also identified. Its high copper affinity is related to the presence of several hydrophobic residues in the neighborhood of histidine. Chromatography of human interleukin-1 beta (hIL-1 beta) and several other proteins containing a single surface-exposed histidine surrounded by several hydrophobic residues confirmed that such a sequence could also serve as a very effective metal binding domain for protein purification using immobilized copper(II) columns.
A power aware study for VTDIRECT95 using DVFS

High performance computing (HPC) using large clusters consumes a huge amount of power. With the emergence of software controlled dynamic voltage and frequency scaling (DVFS), programs can be executed at non-peak frequency in order to reduce CPU power usage, and hence energy consumption. DIRECT is a deterministic global optimization algorithm, implemented in the mathematical software package VTDIRECT95. This paper explores the potential of energy saving for the serial implementation of DIRECT, VTdirect, using DVFS. A performance model and an energy model are developed, and a theoretical bound for energy saving is derived according to the models and experimental data. This work is the first application level study to explore energy savings for large scale nonlinear programming.
SU(2) gauge theory of the Hubbard model and application to the honeycomb lattice

Motivated by recent experiments on the triangular lattice Mott-Hubbard system $\ensuremath{\kappa}\text{\ensuremath{-}}{(\mathrm{BEDT}\text{\ensuremath{-}}\mathrm{TTF})}_{2}{\mathrm{Cu}}_{2}{(\mathrm{C}\mathrm{N})}_{3}$, we develop a general formalism to investigate quantum spin liquid insulators adjacent to the Mott transition in Hubbard models. This formalism, dubbed the SU(2) slave-rotor formulation, is an extension of the SU(2) gauge theory of the Heisenberg model to the case of the Hubbard model. Furthermore, we propose the honeycomb lattice Hubbard model (at half filling) as a candidate for a spin liquid ground state near the Mott transition; this is an appealing possibility, as this model can be studied via quantum Monte Carlo simulation without a sign problem. The pseudospin symmetry of Hubbard models on bipartite lattices turns out to play a crucial role in our analysis, and we develop our formalism primarily for the case of a bipartite lattice. We also sketch its development for a general Hubbard model. We develop a mean-field theory to describe spin liquids and some competing states, and apply it to the honeycomb lattice. On the insulating side of the Mott transition, we find an SU(2) algebraic spin liquid (ASL), described by gapless $S=1∕2$ Dirac fermions (spinons) coupled to a fluctuating SU(2) gauge field. This result contrasts with that obtained via a U(1) slave-rotor approach, which instead found a U(1) ASL. That formulation does not respect the pseudospin symmetry, and is therefore not correct on the honeycomb lattice. We construct a low-energy effective theory describing the ASL phase, the conducting semimetal phase and the Mott transition between them. This physics can be detected in numerical simulations via the simultaneous presence of substantial antiferromagnetic and valence-bond solid correlations. In the SU(2) ASL, these observables have slowly decaying fluctuations in space and time, described by power laws with the same critical exponent. We recover the results of the U(1) slave-rotor formulation in the presence of a strong breaking of pseudospin symmetry. Our analysis suggests that both a third-neighbor electron hopping, and/or pseudospin-breaking terms such as a nearest-neighbor density interaction, may help to stabilize a spin liquid phase.
Carbamate analogues of (-)-physostigmine: in vitro inhibition of acetyl- and butyrylcholinesterase.

Reaction of (−)-eseroline (1) with alkyl, aryl and aralkylisocyanates afforded a series of carbamate analogues of (−)-physostigmine (2) which were assayed for inhibition of acetyl- and butyrylcholinesterase (AChE and BChE, respectively) in vitro. Included in this study were two N-alkyl-substituted carbamates 9 and 14 obtained from (−)-eseroline (1) with dialkylcarbamoyl chlorides, and allophanates 12 and 13 obtained as by-products in the reaction of 1 and benzylcarbamoyl eseroline (8) with benzyl isocyanate. Whereas none of the analogues studied was more potent than 2 against electric eel AChE, and carbamates 6, 7 and 8 were all more than 3 times more potent against human plasma BChE than 2.
Inhibition of nitric oxide synthase ameliorates cellular injury in sickle cell mouse kidneys

Inhibition of nitric oxide synthase ameliorates cellular injury in sickle cell mouse kidneys. Background In previous studies of transgenic sickle cell mice, increased renal expression of inducible nitric oxide synthase (iNOS) and endothelial cell isoform of NOS (EcNOS) was found by Western blot and immunohistochemistry. In addition, putative evidence of peroxynitrite (ONOO - ) formation was found in the form of positive immunostaining and immunoblot for nitrotyrosine. Apoptosis was also detected by DNA strand breakage and TUNEL assay. The present study was carried out to examine the role of NO/ONOO - in mediating renal tubular cell apoptosis in sickle cell mouse kidneys. Methods Mercaptoethylguanidine (MEG), a compound that selectively inhibits iNOS and also is a scavenger of ONOO - , was administered intraperitoneally over a five-day period to control and β s mice. Immunohistochemistry of iNOS and nitrotyrosine, DNA electrophoresis, ApoTACS assay for apoptosis, and Western blot of poly(ADP-ribose) polymerase (PARP) were carried out. Results MEG administration virtually eliminated renal immunostaining of iNOS and nitrotyrosine and prevented DNA strand breakage. In addition, Western blot analysis of PARP, a nuclear DNA-reparative enzyme activated in response to DNA strand breakage, was found to be cleavaged in hypoxic β s mice, but was partially protected in MEG-treated β s hypoxic mice. Finally, apoptosis was markedly reduced by MEG in β s hypoxic mice. Conclusions These observations provide evidence that NO and/or ONOO - are responsible for initiating cell damage, which leads to apoptosis in sickle cell mouse kidneys.
Comparison of tree size structure and growth for partially harvested and even-aged hemlock-spruce stands in southeast Alaska

The effects of partial cutting on tree size structure and stand growth were evaluated in 52 plots in 13 stands in southeast Alaska that were partially harvested 53–96 years ago and compared with 50-year-old even-aged stands that developed after clearcutting. The net basal-area growth was greater in the partially cut plots than in the uncut plots, and basal-area growth generally increased with increasing cutting intensity. However, the basal-area growth of all of the partially harvested stands was significantly less than the growth of 50-year-old even-aged stands, and net basal area growth over the 50 year period since partial harvesting was about 33–43% of the growth of the even-aged stands. Partial cutting maintained stand structures similar to uncut old-growth stands, and the cutting had no significant effect on tree species composition. The tree size distribution of the partially harvested stands was far more complex and well distributed in comparison with the 50-year-old even-aged stands, and included the presence of several trees with diameters of more than 100 cm. These trees included both large-diameter spruce and hemlock trees and were a distinctive structural feature that was noticeably lacking in the even-aged stands.
In Vivo Assessment of Pituitary Gland Volume with Magnetic Resonance Imaging: The Effect of Age*

We used sagittal and coronal T1 weighted magnetic resonance images, at 1.5 Tesla, to measure the height, width, length, and cross-sectional area and to generate two estimates of pituitary gland volume in 35 normal volunteers aged 26-79 yr (19 females and 16 males). Subjects over 50 yr of age had significantly smaller pituitary gland height (P = 0.03), area (P = 0.04), and volume (P = 0.04) than those under 50 yr (by two-tailed t test). Overall, age was negatively correlated with pituitary volume (V1: r = -0.51; P = 0.003; V2: r = -0.47; P = 0.008), area (r = -0.43; P = 0.009), and height (r = -0.46; P = 0.005), but not with pituitary length or width. There were no statistically significant differences in pituitary size between men and women (by two-tailed t test). These findings suggest that pituitary gland height provides a good single measure for the assessment of pituitary gland size and that age must be controlled for in studies of pituitary gland size.
HIV-1 Nef Impairs Heterotrimeric G-protein Signaling by Targeting Gαi2 for Degradation through Ubiquitination

The HIV Nef protein is an important pathogenic factor that modulates cell surface receptor trafficking and impairs cell motility, presumably by interfering at multiple steps with chemotactic receptor signaling. Here, we report that a dominant effect of Nef is to trigger AIP4 E3 ligase-mediated Gαi2 ubiquitination, which leads to Gαi2 endolysosomal sequestration and destruction. The loss of the Gαi2 subunit was demonstrable in many cell types in the context of gene transfection, HIV infection, or Nef protein transduction. Nef directly interacts with Gαi2 and ternary complexes containing AIP4, Nef, and Gαi2 form. A substantial reversal of Gαi2 loss and a partial recovery of impaired chemotaxis occurred following siRNA knockdown of AIP4 or NEDD4 or by inhibiting dynamin. The N-terminal myristoyl group, 62EEEE65 motif, and 72PXXP75 motif of Nef are critical for this effect to occur. Nef expression does not affect a Gqi5 chimera where the five C-terminal residues of Gq are replaced with those of Gαi2. Lysine at position 296 of Gαi2 was identified as the critical determinant of Nef-induced degradation. By specifically degrading Gαi2, Nef directly subverts leukocyte migration and homing. Impaired trafficking and homing of HIV Nef-expressing lymphocytes probably contributes to early immune dysfunction following HIV infection.
The Measurement of General Motor Capacity and General Motor Ability

(1934). The Measurement of General Motor Capacity and General Motor Ability. Research Quarterly. American Physical Education Association: Vol. 5, No. sup1, pp. 46-61.
Sustainable tourism or sustainable development? Financial crisis, ecotourism, and the 'Amazing Thailand' campaign.

Although the issues of sustainable tourism and sustainable development are receiving increasing attention from tourists, government planners and scholars, few studies have examined their overlap, tensions and complex linkages in practice. In southern Thailand, the sustainability of tourism, defined as the ongoing growth and survival of the tourism industry, has compromised the ecological sustainability of key tourism destinations sites. The recent financial crisis has forced the Thai government to sacrifice long-term sustainability for the sake of quick, and desperately needed foreign exchange. The 'Amazing Thailand' promotional campaign, which aims to attract 17 million tourists over 1998 and 1999, promises to exacerbate further the environmental degradation of tourism destinations in southern Thailand by pushing for enhanced tourist numbers. Ironically, by changing the composition of tourist arrivals (and in particular, attracting more European and North American tourists) the currency devaluations asso...
History of ceramic orthopedic implants

Abstract Until recently, ceramic materials have been, for the most part, overlooked in the field of biomaterials research. Plaster of Paris, a resorbable ceramic, has been used in limited experimental and clinical applications since 1892 (1). The first significant step in the use of ceramics for bone replacement was in 1963 when Smith reported the development and use of Cerosium, a porous ceramic impregnated with epoxy resin (2). Although Cerosium did not prove to be a suitable replacement material for bone, it did stimulate interest in further work with porous ceramics. Since Smith's investigation with Cerosium, substantial information has been developed concerning bone ingrowth and the biocompatibility of numerous ceramic materials. The literature suggests that ceramics will play a major role as orthopedic implant materials. The potential of ceramics as biomaterials stems directly from their chemical stability in the physiological environment. Furthermore, ceramics can be composed of ions commonly found in the physiological environment (calcium, potassium, magnesium, sodium, etc.) and of ions showing limited toxicity to body tissue (aluminum and titanium). Thus, even in those cases where ceramics may undergo long-term degradation, the constituent ion concentration in adjacent tissues is easily controlled by the body's natural regulatory mechanisms.
Algebraic complexity theory

Algebraic complexity theory, the study of the minimum number of operations sufficient to perform algebraic computations, is surveyed with emphasis on the general theory of bilinear forms and two of its applications: polynomial multiplication and matrix multiplication. Though by no means exhausting algebraic complexity theory, these topics illustrate well its development and its methods, and provide examples of its most striking successes.
Change in oral absorption of tacrolimus in a liver transplant recipient after reversal of jejunoileal bypass: case report.

Introduction. Jejunoileal bypass (JIB) was, at one time, a popular surgical technique for the treatment of morbid obesity. However, this operation was also associated with major complications. Consequently, many such procedures were eventually reversed. One of the most serious of these complications was liver failure. For those patients who developed cirrhosis, liver transplantation was one therapeutic alternative. Tacrolimus is one of the primary immunosuppressive agents used in liver transplantation. It is effective to prevent acute rejection episodes, but shows a narrow therapeutic index and can cause nephrotoxicity and neurotoxicity. This report describes the change in tacrolimus absorption that was observed after JIB reversal in a 57-year-old female liver transplant recipient. Results. Prior to JIB reversal, the mean tacrolimus dose was 7 mg twice daily with a whole-blood tacrolimus concentration ranging from 5.2 to 6.4 ng/mL. There was no appreciable peak in tacrolimus concentration, and the area under the concentration-time curve (AUC) was 10.9 ng/mL/h. After reversal, the daily tacrolimus dose was decreased to 5 mg twice daily, with a now-discernable peak concentration at 3 hours postdose. Furthermore, the AUC increased 90% to 20.7 ng/mL/h. Conclusion. After JIB reversal, the patient showed higher systemic levels of tacrolimus and required lower steady-state doses. It is therefore imperative that such patients be monitored closely to avoid tacrolimus-related toxicity.
A REGIONAL ANALYSIS OF AIR QUALITY STANDARDS, COAL CONVERSION, AND THE STEAM‐ELECTRIC COAL MARKET*

In the United States coal-fired electric power plants generate the major portion of sulfur emissions, accounting for most of the approximately 57 percent of emissions attributable to electric utilities. Most states have plans to reduce sulfur emissions in the near term in conventional steam electric generation by regulating the type of fuel used. Solutions are characterized as determining the most efficient network of production, distribution and use for coal in steam-electric generating plants. The regional impacts of sulfur-reducing technology, which would permit current high sulfur coal production, are analyzed for their interaction with coal conversion and air quality. Regional air quality standards which limit average sulfur emissions from coal-fired power plants can have important interactions with the spatial location of production activities if a premium is placed on low sulfur emissions. Midwestern high sulfur coal cannot compete with Western coal with the probable operating costs for sulfur reducing technologies.
Analysis of unfractionated heparin dose requirements to target therapeutic anti-Xa intensity during pregnancy

Abstract Introduction Unfractionated heparin (UFH) does not cross the placenta and has demonstrated utility in the prevention and treatment of thrombosis during pregnancy. Limited information is available to guide initiation and monitoring of therapeutic UFH targeting an anti-Xa concentration of 0.3-0.7 u/ml during pregnancy. The objective of this study was to describe UFH doses and monitoring strategies required to achieve and maintain therapeutic anti-Xa intensity in a cohort of women treated with UFH during pregnancy. Materials/Methods Patients prescribed anti-Xa adjusted UFH during pregnancies occurring between January 1998 and March 2005 were included. Results A total of 39 pregnancies for 37 women were identified. Unfractionated heparin doses were titrated to achieve a mid-interval anti-Xa level of 0.3-0.7 u/ml. Patients required a median 6.5 days and a mean UFH dose of 403.5 u/kg/day to achieve therapeutic anti-Xa levels. Most anti-Xa levels were within the target range (59%). The final UFH dose/kg required at the end of pregnancy was similar to that at the first therapeutic level (P > 0.05); however some patients did require dose modification. Patients required a mean 14.1 anti-Xa determinations and 4.6 dose modifications during a mean 23.9 weeks of antenatal UFH therapy. Patient weight and UFH dose at the first therapeutic anti-Xa level were correlated (r = 0.383, P = 0.018). Conclusions Pregnant women required a mean UFH dose of 403.5 u/kg/day to achieve midinterval anti-Xa levels of 0.3-0.7 u/ml. The required dose was correlated with patient weight and most anti-Xa measurements were within the target range.
Physicians at the Medicine/Psychiatric Interface: What Do Internist/Psychiatrists Do?

Studies have convincingly demonstrated that some 50% of patients in primary care settings have both medical and psychiatric diagnoses requiring dual treatment. The concept of primary care psychiatry has emerged in recent years as one way to address this problem. In 1979 the first combined medicine-psychiatry residency was formed. There are now over 20 such programs, but there is little information on how these doubly trained physicians actually practice. In 1997, the authors surveyed the 268 physicians with board certification in both internal medicine and psychiatry that were listed with the American Board of Medical Specialties. Only 15% practiced any type of medicine at all; the rest were involved only in the practice of psychiatry. Although 75% identified themselves only as psychiatrists and worked predominantly in psychiatry, 95% reported using both their medical and psychiatric training in their professional work. They reported that the dual training made them better physicians, improved their professional credibility, and enhanced their diagnostic skills. Several significant barriers were discovered that directly affect the ability of physicians to practice in two fields. Findings, study limitations, and potential implications for the field and its patients are discussed.
In the Eye of the Beholder: How Information Shortcuts Shape Individual Perceptions of Bias in the Media

In the Eye of the Beholder: How Information Shortcuts Shape Individual Perceptions of Bias in the Media
Solution-Based Straight and Branched CdTe Nanowires

The synthesis, characterization, and optical properties of high quality straight and branched CdTe nanowires (NWs) are described. A solution-based (solution−liquid−solid) approach is used to synthesize the NWs by employing a low melting bimetallic nanoparticle catalyst to induce one-dimensional (1D) growth. This leverages advances in the development of high quality colloidal quantum dots (QDs) with emerging techniques for manufacturing 1D nanomaterials. Resulting straight and branched CdTe NWs have diameters below twice the corresponding bulk exciton Bohr radius and, as a consequence, exhibit confinement effects in their linear absorption. Size distributions range from 15% to 20%, with NW lengths commonly exceeding 10 μm. Intrawire diameter variations are on the order of 5%. High-resolution transmission electron microscopy (TEM) images reveal that the wires are crystalline and grow exclusively along the and directions of the corresponding zincblende and wurtzite phases. Branched NW morphologi...
A higher-order Godunov scheme coupled with dynamic local grid refinement for flow in a porous medium

Abstract Today's reservoir simulators are generally inefficient due to the use of low-order accurate schemes in space and time on regular grids. The numerical diffusion inherent in the single-point upstream weighting scheme can cause large errors in the numerical solutions, which can only be removed by the use of very fine uniform grids with many grid blocks. The aim of this work is to develop a method which can produce physically reliable and accurate results efficiently. A higher-order Godunov scheme is coupled with dynamic grid adaptivity, where grid blocks are inserted in highly active regions of the flow field and removed from regions of inactivity, thereby concentrating the computational effort where it is most needed. The quality of results computed by the adaptive higher-order scheme are comparable with those computed by the higher-order scheme on a uniform grid, globally refined to the level of the finest adaptive grid zones, while great savings in computer time are obtained. The adaptive high-order scheme is vastly superior compared to the first-order scheme on a uniform or adaptive grid. The results presented demonstrate the benefits of the method in reservoir simulation.
Recent research results in iris biometrics

Many security applications require accurate identification of people, and research has shown that iris biometrics can be a powerful identification tool. However, in order for iris biometrics to be used on larger populations, error rates in the iris biometrics algorithms must be as low as possible. Furthermore, these algorithms need to be tested in a number of different environments and configurations. In order to facilitate such testing, we have collected more than 100,000 iris images for use in iris biometrics research. Using this data, we have developed a number of techniques for improving recognition rates. These techniques include fragile bit masking, signal-level fusion of iris images, and detecting local distortions in iris texture. Additionally, we have shown that large degrees of dilation and long lapses of time between image acquisitions negatively impact performance.
Thyrotropic activity of basic isoelectric forms of human chorionic gonadotropin extracted from hydatidiform mole tissues

hCG is known to have thyroid-stimulating activity and may cause hyperthyroidism in patients with trophoblastic diseases. hCG occurs in normal and molar pregnancy with breaks or nicks in the alpha- or beta-subunit peptide linkage and with substantial heterogeneity in the composition and degree of branching within the oligosaccharide side-chains. The bioactivity of hCG is markedly influenced by these structural variations. We purified hCG from five hydatidiform moles, using chromatofocusing separation after gel filtration. The hCG molecules were fractionated according to their isoelectric points, with a linear pH gradient from 3.2-6.1 and a final 1.0 mol/L NaCl step elution. The hCG immunoreactivity of each fraction was measured by RIA, and the thyroid-stimulating activity of hCG was determined by means of the cAMP response in Chinese hamster ovary cells expressing functional human TSH receptors (Chinese hamster ovary-JP09 cells). The chromatofocusing profile showed that hCG from the moles was eluted in six or seven major peaks at pH 6.1, 5.5, 5.3, 4.8, 3.8, and 3.2 and with 1.0 mol/L NaCl, whereas hCG extracted from serum of hydatidiform moles and standard hCG preparation CR-127 extracted from pregnancy urine showed only small peaks at pH greater than 5.3. Each fraction increased cAMP production significantly in Chinese hamster ovary-JP09 cells. The relative bioactivity/immunoreactivity, represented as the ratio of cAMP/hCG (picomoles per IU), was significantly higher in basic components (pI 6.1, 6.2 +/- 1.2; pI 5.5, 4.4 +/- 2.7; pI 5.3, 5.8 +/- 0.3) than in hCG CR-127 (bioactivity/immunoreactivity, 0.42; P < 0.05). The difference in pI of each hCG isoform was attributable to the extent of sialylation; basic hCG isoforms contained less sialic acid by immunological detection using lectins. These results indicate that isoforms of hCG with more thyrotropic activity were produced by trophoblastic tissues in patients with hydatidiform mole. We speculate that these isoforms of hCG may be responsible for the hyperthyroidism in some patients with hydatidiform moles.
Decomposition in Reliability Analysis of Fault-Tolerant Systems

Two important problems which arise in modeling fault-tolerant systems with ultra-high reliability requirements are discussed. 1) Any analytic model of such a system has a large number of states, making the solution computationally intractable. This leads to the need for decomposition techniques. 2) The common assumption of exponential holding times in the states is intolerable while modeling such systems. Approaches to solving this problem are reviewed. A major notion described in the attempt to deal with reliability models with a large number of states is that of behavioral decomposition followed by aggregation. Models of the fault-handling processes are either semi-Markov or simulative in nature, thus removing the usual restrictions of exponential holding times within the coverage model. The aggregate fault-occurrence model is a non-homogeneous Markov chain, thus allowing the times to failure to possess Weibull-like distributions. There are several potential sources of error in this approach to reliability modeling. The decomposition/aggregation process involves the error in estimating the transition parameters. The numerical integration involves discretization and round-off errors. Analysis of these errors and questions of sensitivity of the output (R(t)) to the inputs (failure rates and recovery model parameters) and to the initial system state acquire extreme importance when dealing with ultra-high reliability requirements.
Facile prediction of total heat transfer from simple solid bodies to neighboring fluids: A viable alternative to Gröber charts

Abstract In the analysis of unsteady heat conduction for simple solid bodies (large plate, long cylinder and sphere), the first Heisler chart provides the dimensionless center temperature varying with the dimensionless time and parameterized by the Biot number. The second Heisler chart furnishes the ratio between the dimensionless off-center temperatures and the dimensionless center temperature (taken from the first Heisler chart) varying with the Biot number. A third Grober chart renders the dimensionless total heat transfer in terms of the dimensionless time and the Biot number. The tandem of Heisler/Grober charts constitutes integral material in the chapter on unsteady heat conduction in most heat transfer textbooks. The present study addresses a natural interconnection (so far unexplored in the specialized literature) between the dimensionless mean temperature and the dimensionless center temperature (taken from the first Heisler chart) affected by the Biot number. The approach to be proposed in this study is conducive to the construction of a new chart equivalent in format to the second Heisler chart for the three simple solid bodies, but including only a single curve. Alternatively, each new chart is channeled through a compact correlation equation whose evaluation is easy. Thermal design engineers and students enrolled in heat transfer courses will be the beneficiaries of the outcome of this technical paper.
Bismuth-induced surface structure and morphology in III-V semiconductors

Bi is the largest group V element and has a number of advantages in III-V semiconductor properties, such as bandgap reduction, spin-orbit coupling, a preserved electron mobility over III-V-N materials, and nearly ideal surfactant properties resulting in a surface smoothing effect on GaAs. However, the mechanism for this behavior is not well understood. Insight on the mechanism is obtained through study of the Bi-terminated GaAs surface morphology and atomic reconstructions produced via molecular beam epitaxy (MBE). Experimental scanning tunneling microscopy (STM) characterization of the Bi/GaAs surface reveal disordered (1x3), (2x3), and (4x3) reconstructions, often sharing the same reflective high-energy electron diffraction (RHEED) patterns. Roughness on the micron length scale decreases as the step widen, attributed to the concurrent increase of opposite direction step edges on the nanometer length scale. Corresponding cluster expansion, density functional theory (DFT), and Monte Carlo simulations all point to the stability of the disordered (4x3) reconstruction at finite temperature as observed in experimental STM. The effects of incorporated Bi are determined through epitaxial GaSbBi growth on GaSb with various Ga:Sb:Bi flux ratios. Biphasic surface droplets are observed with sub-droplets, facets, and substrate etching. Despite the rough growth front, X-ray diffraction (XRD) and Rutherford backscatter (RBS) measurements show significant Bi incorporation of up to 12% into GaSb, along with a concurrent increase of background As concentration. This is attributed to a strain auto-compensation effect. Bi incorporation of up to 10% is observed for the highest Bi fluxes while maintaining low surface droplet density.
Establishing a Career: Developmental Tasks and Coping Responses.

Abstract The present study identified coping responses that effectively address the six developmental tasks in the career establishment stage. The critical incident technique was used to make explicit the tacit knowledge about task coping used by fifty workers who were successfully coping with the developmental tasks of the establishment stage. The workers were systematically selected to represent different phases in the establishment stage and diverse occupational fields and levels. The workers described the major coping behaviors that they used to deal with each of the six development tasks of the establishment stage. Personnel specialists identified and principal component analysis organized the pattern of coping responses pertinent to each of the developmental tasks. This information is useful in designing anticipatory guidance and psycho-educational programs for students about to face the school-to-work transition and for workers in different phases of establishing their careers.
Collaboration in Staff Development--Variations on the Concept.

Two forms of col laborative planning for inservice edu cation have been identified: egalitar ian and dialectical. The local setting may render one form more appro priate than the other. A project di rector who is knowledgeable of both forms is better equipped to guide staff development. efforts.
Circadian rhythm in susceptibility of house flies and Madeira cockroaches to pyrethrum.

Pyrethrum aerosol was disseminated each hour in the presence of separate groups of house flies, Musca domestica L., and Madeira cockroaches, Leucophaea maderae (F.), kept before and during tests under standardized conditions and on a schedule of 15 or 17 hours of artificial light alternating with 9 or 7 hours of darkness. Both species consistently demonstrated a circadian rhythm in susceptibility to the aerosol judged by the use of 2 endpoints-knockdown and death. The acrophase (crest) of susceptibility in both species occurred during the last quarter of the daily light span, about midafternoon.
Amorphous SiC film formation on Si(100) using electron beam excitation

Abstract The effect of electron impact on methylsilane (CH3SiH3) conversion to amorphous-Si0.5C0.5:H (a-Si0.5C0.5:H) films on Si(100) has been studied by Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption (TPD), and low energy electron diffraction (LEED). It is found that electron impact greatly enhances CH3SiH3 decomposition on Si(100) at both 90 K and 300 K, resulting in a-Si0.5C0.5:H thin film formation. Thermal annealing of the film causes hydrogen desorption and amorphous silicon carbide (a-SiC) formation. Upon annealing to temperatures above 1200 K, the a-SiC film became covered by a thin silicon layer as indicated by AES studies. Ordered structures are not produced by annealing the a-SiC up to 1300 K.
Brief announcement: serial-parallel reciprocity in dynamic multithreaded languages

In dynamically multithreaded platforms that employ work stealing, there appears to be a fundamental tradeoff between providing provably good time and space bounds and supporting SP-reciprocity, the property of allowing arbitrary calling between parallel and serial code, including legacy serial binaries. Many known dynamically multithreaded platforms either fail to support SP-reciprocity or sacrifice on the provable time and space bounds that an efficient work-stealing scheduler could otherwise guarantee.We describe PR-Cilk, a design of a runtime system that supports SP-reciprocity in PR-Cilk and provides provable bounds on time and space. In order to maintain the space bound, PR-Cilk uses subtree-restricted work stealing. We show that with subtree-restricted work stealing, PR-Cilk provides the same guarantee on stack space usage as ordinary Cilk. The completion time guaranteed by PR-Cilk is slightly worse than ordinary Cilk. Nevertheless, if the number of times a C function calls a Cilk function is small, or if each Cilk function called by a C function is sufficiently parallel, PR-Cilk still guarantees linear speedup.
Review of AAPM task group no. 43 recommendations on interstitial brachytherapy sources dosimetry

In 1995, the American Association of Physicists in Medicine (AAPM) Task Group No. 43 (TG-43) published its recommendations on the dosimetry of interstitial brachytherapy sources. The report recommended the use of a new dose calculation formalism based on measured quantities. The formalism in modular form permits the computation of doses in two dimensions for 103Pd, 125I, and 192Ir sources. The TG-43 dose calculation formalism introduced new and updated quantities such as air kerma strength, dose rate constant, radial dose function, anisotropy function and anisotropy factor. The dose rate obtained using the TG-43 dose calculation formalism and updated source dosimetry data can be expected to be different from some of the currently used systems by as much as 17%. For the same treatment and implementing the TG-43 dosimetry with point source approximation, the widely prescribed dose of 160 Gy for 125I permanent implants using model 6711 sources changes to 144 Gy. In addition to the dose calculation formalism, TG-43 report also stated that the air kerma strength provided by NIST is estimated to be approximately 7-10% higher than it should be, due to low energy photon contamination for 125I. This difference has not been accounted for in the TG-43 report.
Imperfection in the Capital Market and the Institutional Arrangement of Inheritance

In the theoretical literature of the life-cycle savings model originating from Irving Fisher's conception of optimal intertemporal consumption behaviour it has been customarily assumed that the capital market is perfect; that is, one can borrow or lend freely in the capital market. This assumption has also been made in the models of Yaari [9], Meade [5] and Atkinson [1] that include the bequest motive upon which our analysis is based.3 One of the important implications of these analyses, though unnoted, is that under the assumption of a perfect capital market the optimal programme is neutral with respect to the actual form in which inheritance is bequeathed. Namely, the same optimal programme can be followed no matter whether the bequest is given as a gift inter vivos or as a transfer at death if one adjusts the amount of borrowing and lending suitably in the capital market. When there is imperfection in the capital market, this neutrality property is no longer expected to be true. The purpose of this paper is to examine the impact of imperfection in the capital market on the welfare of individuals, to examine whether or not we can give any prediction with regard to the types of inheritance arrangements that may appear and, finally, to examine some of the welfare implications of inheritance taxation, under the assumption of a certain representative type of capital market imperfection. Our analysis proceeds as follows. The first two sections evaluate the effects of imperfection in the capital market on the optimum path of consumption and the optimum amount of bequests under alternative inheritance schemes. The third section uses the results of the preceding sections to discuss the patterns of choice of inheritance arrangement and also examines some qualitative effects of inheritance taxation. Finally, the fourth section presents some qualificatory remarks of the present analysis.
Phytochrome regulated gene expression.

Abstract Light is used by plants as a signal for many physiological and developmental processes. Phytochrome is the most extensively studies family of photoreceptors that plants use to perceive the presence and quality of light in their environment. While the initial action of the phytochrome molecule is not yet known, one important kind of response, changes in the expression of specific nuclear genes, has been intensively investigated. Although phytochrome-regulated promoters are complex and can also respond to other signals, specific DNA elements that are involved in conferring phytochrome responsiveness have been identified. Potential signal transduction pathway components include G proteins, cyclic GMP and Ca2+/calmodulin. In addition, the study of transcription factors involved in phytochrome-regulated gene expression has yielded insights into some of the final steps of transcriptional regulation by phytochrome.