cssi/SciSciGPT-SciSciNet huggingface dataset:
Utility of the Hospital Frailty Risk Score for Predicting Adverse Outcomes in Degenerative Spine Surgery Cohorts

Background As spine surgery becomes increasingly common in the elderly, frailty has been used to risk stratify these patients. The Hospital Frailty Risk Score (HFRS) is a novel method of assessing frailty using International Classification of Diseases, Tenth Revision (ICD-10) codes. However, HFRS utility has not been evaluated in spinal surgery. Objective To assess the accuracy of HFRS in predicting adverse outcomes of surgical spine patients. Methods Patients undergoing elective spine surgery at a single institution from 2008 to 2016 were reviewed, and those undergoing surgery for tumors, traumas, and infections were excluded. The HFRS was calculated for each patient, and rates of adverse events were calculated for low, medium, and high frailty cohorts. Predictive ability of the HFRS in a model containing other relevant variables for various outcomes was also calculated. Results Intensive care unit (ICU) stays were more prevalent in high HFRS patients (66%) than medium (31%) or low (7%) HFRS patients. Similar results were found for nonhome discharges and 30-d readmission rates. Logistic regressions showed HFRS improved the accuracy of predicting ICU stays (area under the curve [AUC] = 0.87), nonhome discharges (AUC = 0.84), and total complications (AUC = 0.84). HFRS was less effective at improving predictions of 30-d readmission rates (AUC = 0.65) and emergency department visits (AUC = 0.60). Conclusion HFRS is a better predictor of length of stay (LOS), ICU stays, and nonhome discharges than readmission and may improve on modified frailty index in predicting LOS. Since ICU stays and nonhome discharges are the main drivers of cost variability in spine surgery, HFRS may be a valuable tool for cost prediction in this specialty.
Phonon-isotope scattering and thermal conductivity in materials with a large isotope effect: A first-principles study

The interplay between phonon-isotope and phonon-phonon scattering in determining lattice thermal conductivities in semiconductors and insulators is examined using an ab initio Boltzmann transport equation approach. We identify materials with large enhancements to their thermal conductivities with isotopic purification, known as the isotope effect, and we focus in particular on results for beryllium-VI compounds and cubic germanium carbide. We find that germanium carbide and beryllium selenide have very large room temperature isotope effects of 450$%$, far larger than in any other material. Thus, isotopic purification in these materials gives surprisingly high intrinsic room temperature thermal conductivities, over 1500 Wm${}^{\ensuremath{-}1}$ K${}^{\ensuremath{-}1}$ for germanium carbide and over 600 Wm${}^{\ensuremath{-}1}$ K${}^{\ensuremath{-}1}$ for beryllium selenide, well above those of the best metals. In compound semiconductors, a large mass ratio of the constituent atoms and large isotope mixture for the heavier atom gives enhanced isotope scattering. A frequency gap between acoustic and optic phonons (also due to a large mass ratio) and bunching of the acoustic phonon branches give weak anharmonic scattering. Combined, weak anharmonic phonon scattering and strong isotope scattering give a large isotope effect in the materials examined here. The physical insights discussed in this work will help guide the efficient manipulation of thermal transport properties of compound semiconductors through isotopic modification.
Ethical Dilemmas in Global Clinical Electives

A recent Association of American Medical Colleges survey found that 30% of graduates of U.S. medical schools reported participating in global health experiences (Association of American Medical Colleges, 2010). Previous research has shown that international rotations foster cultural awareness, elicit a deeper understanding of poverty, and influence students to pursue careers caring for underserved populations (McKinley, Williams, Norcini, & Anderson, 2008; Ramsey, Haq, Gjerde, & Rothenberg, 2004; Shaywitz & Ausiello, 2002). Despite considerable interest in global health education from students and its reported benefits, however, most schools have not integrated formal global health programs into their curricula (Izadnegahdar et al., 2008; Panosian & Coates, 2006). Only recently have formal ethical guidelines for global health experiences been introduced (Crump, Sugarman, & Working Group on Ethics Guidelines for Global Health Training, 2010; Provenzano et al., 2010). The lack of an institutionalized framework for global health education has had important ethical and educational implications for medical students who pursue electives in resource-poor settings. International research programs are governed by well-developed clinical guidelines, but global clinical electives carry with them many ethical challenges that have received relatively little attention (Shah & Wu, 2008). While international research programs contribute to the larger academic discourse and are subject to institutional review board approval and other ethical standards, clinical programs that involve students also impact the local community and thus require similar attention. In particular, the perspectives and needs of institutions that host and support foreign students at the international clinical sites in low-resource settings (“host institutions”) have been neglected. Electives have been described as a “one-way opportunity” that favor students who visit from wealthier institutions (Mutchnick, Moyer, & Stern, 2003). Paradoxically, the disproportionate focus on the benefits for visiting students rather than for the host institution reinforces the same disparities in wealth and opportunity that global health programs seek to address. The case studies presented here, based on the experiences of the student authors, show the need for a more cohesive, informed approach to global health electives. Through building formal, long-term, global North-South partnerships, medical schools and host institutions may prevent many of the ethical dilemmas that arise as a result of global clinical experiences (Horton, 2000). We recommend specific guidelines to ensure that clinical electives in low-resource settings are ethical and mutually beneficial for both visiting students and host institutions.
A Queue-Stabilizing Framework for Networked Multi-Robot Exploration

Motivated by planetary exploration, we consider the problem of deploying a network of mobile robots to explore an unknown environment and share information with a stationary data sink. The configuration of robots affects both network connectivity and the accuracy of relative localization. Robots explore autonomously and can store data locally in their queues. When a communication path exists to the data sink, robots transfer their data. Because robots may fail in a non-deterministic manner, causing loss of the data in their queues, enabling communication is important. However, strict constraints on connectivity and relative positions limit exploration. To take a more flexible approach to managing these multiple objectives, we use Lyapunov-based stochastic optimization to maximize new information while using virtual queues to constrain time-average expectations of metrics of interest. These include queueing delay, network connectivity, and localization uncertainty. The result is a distributed online controller which autonomously and strategically breaks and restores connectivity as needed. We explicitly account for obstacle avoidance, limited sensing ranges, and noisy communication/ranging links with line-of-sight occlusions. We use queuing theory to analyze the average delay experienced by data in our system and guarantee connectivity will be recovered when feasible. We demonstrate in simulation that our queue-stabilizing controller can reduce localization uncertainty and achieve better coverage than two state of the art approaches.
New River Apparel: Trot or Gallop?

Marjorie Burnett, who runs a clothing outlet with lagging revenues in Tennessee, is considering taking a gamble on starting a new business. She has to decide whether expansion—offering even more products—is the answer to increasing her revenue, and whether would that decision be more profitable than her present business, given that the storefront she's considering is in a relatively unpopulated rural area. Would a new business be worth the investment, or should she stick with the business—and the risks—she already knows? Excerpt UVA-ENT-0194 Rev. Aug. 8, 2019 New River Apparel: Trot or Gallop? Introduction Marjorie Burnett sat in her office in Chattanooga, Tennessee, deeply in thought. In a few months, she would no longer be here—she had decided to move her business to Monteagle, a relatively unpopulated location in rural Tennessee. The big question was how to do so: she could either keep the same store format with some product adjustments to fit the new location, or take the gamble to massively expand and change the business model. Was expansion—offering even more products—the answer to increasing revenue, and would that decision be more profitable than her present business? The biggest risk was whether a new store, in a relatively unpopulated location in rural Tennessee, could sell merchandise steadily enough to sustain itself while Burnett figured out how to manage a business related to—yet very different from—her current one. The move would mean a transition from high-end clothing outlet to outdoor outfitter. Burnett even had a potential name change in mind: New River Apparel would become Mountain Outfitters. . . .
Hépatites virales aiguës à Herpesviridae et grossesse : mise au point

Points essentiels Les hepatites virales pendant la grossesse sont assez bien definies, notamment les hepatites A, B, C, D et E. En revanche, les hepatites virales dites non alphabetiques, comme les hepatites a Herpesviridae [cytomegalovirus (CMV), varicelle-zona virus (VZV), Epstein-Barr virus (EBV) ou herpes simplex virus (HSV)] sont peu decrites. L’hepatite herpetique est plus frequente pendant la grossesse, avec un risque neonatal en peripartum. Une infection a VZV est a risque pour le fœtus notamment, avec une possible transmission verticale a type de varicelle congenitale ou neonatale. Alors que l’infection a EBV semble benigne pendant la grossesse, celle a CMV est a fort risque de malformations congenitales. La prise en charge de ces patientes depend donc du terme de la grossesse, mais surtout du type de virus en cause. Le diagnostic etiologique est donc indispensable pour adapter les traitements et le suivi obstetrical.
Living in an Ambient Intelligent World

The contents of this book reflect the coverage given to the ethics of ambient intelligence at the Safeguards in a World of Ambient Intelligence (SWAMI) conference (2006). The focus is on the ethical issues of embedding low visibility, networked sensors into ever more environments (called ambient intelligence or AmI in Europe and ubiquitous computing or networked computing in America and Japan). While AmI conjurors up a vision with an emphasis on greater user-friendliness, more efficient services support and user empowerment, there is also an inherent dark side when intelligence is embedded in the environment and accessible anywhere and at any time including by those on the move. This is because the ever-expanding scope of human activity within this electronic ecosystem raises a range of technical challenges associated with privacy, identity and security of vast quantities of recorded behavioural, personal and biological data. Additionally the increasing intelligence of devices and applications have implications for security, product liability and the demarcation of ownership and control of the available information. Perhaps the biggest challenge is related to defending the world of ambient intelligence against attacks from viruses, fraud, masquerade and general cyber terrorism. So it is timely that this book sets out to considers how and to what extent it will be possible to overcome the problematic implications of the dark side of ambient intelligence.
Vaporization of strontium, barium, lanthanum, and uranium from mixtures of urania, zirconia, steel, and concretes at 2150 and 2400 K

The vaporization of strontium, barium, and lanthanum from mixtures of their oxides with urania, zir-conia, and concrete is determined with the objective of understanding the release of these refrac...
Urban biodiversity and climate change

Climate change has the potential to affect urban vegetation diversity. The effects of climate change will vary across the globe. Global climate change along with increasing urbanization and its associated heat islands could lead to significantly warmer temperatures in developing regions. The local climate and soils, urban processes, vectors of plant and seed transmission, and vegetation management decisions combine to produce the current biodiversity exhibited in cities. The diversity of urban vegetation composition has changed through time with many cities currently having species richness and Shannon-Wiener diversity index values greater than native forest stands. Vegetation managers can affect future biodiversity and help offset potential environmental changes by understanding these changes and designing vegetation plans to sustain future plant health and diversity, and ensure ecosystem services that help mitigate climate changes.
Software upgrade for the DIII-D neutral beam control systems

The Neural Beam Software Upgrade project was launched in early 1990. The major goals were to upgrade the MAX IV operating system to the latest version (K.1), use standard MODCOMP software (as much as possible), and to develop a very user-friendly, versatile system. Accomplishing these goals required new software to be developed and modifications to existing applications software to make it compatible with the latest operating system. The custom operating system modules to handle the message service and interrupt handling were replaced by the standard MODCOMP intertask communication (ITC) and interrupt routines that are part of the MAX IV operating system. The message service provides the mechanism for doing shot task sequencing. The interrupt routines are used to connect external interrupts to the system. The new software developed consists of a task dispatcher, a screen manager, and interrupt tasks. The existing applications software had to be modified to be compatible with the MODCOMP ITC services and consists of the Modcomp Infinity Data Base Manager, a multiuser system, and menu-driven operator system interface routines using the Infinity Data Base Manager. >
The Effect of Alpha-Mannose-Terminal Oligosaccharides on the Survival of Glycoproteins in the Circulation: Rapid Uptake and Catabolism of Bovine Pancreatic Ribonuclease B by Nonparenchymal Cells of Rat Liver

125I-Labeled ribonuclease B (RNase B), injected intravenously, is rapidly cleared from the rat circulation (t12 ∼ 15 min). Clearance of this glycoprotein depends on specific recognition of the α-mannosyl residues of the attached oligosaccharide and is inhibited by the coinjection of an excess of unlabeled RNase B or yeast mannan, but not by RNase A, dextrans, galactan, or asialofetuin. Following 125I-labeled RNase B injection into nephrectomized rats, radioactivity accumulated primarily in the lysosomal subcellular fraction in the liver and was rapidly degraded to low molecular weight iodinated products. Free iodide began to accumulate in the stomach and intestines after 30 min. Liver, spleen, and bone marrow were most active, on a weight basis, in the clearance of RNase B. At 15 min after the injection of 125I-labeled RNase B, parenchymal and nonparenchymal cells were isolated from liver following perfusion with dilute formalin and collagenase. More than 90% of the radioactivity was localized in the nonparenchymal cell fraction. The evidence indicates that mannose-dependent glycoprotein clearance from the circulation occurs primarily in tissues characteristic of the reticuloendothelial system.
Preventive Health Behavior: Conceptual Approaches

A variety of conceptual approaches to understanding health behavior exist. While an individual's health behavior is likely the product of numerous levels of influence, including interpersonal, group, community, and institutional/policy levels, much theory and research have focused on understanding health behavior at the individual level. In this realm, there are a variety of behavioral theories that advance our understanding of what motivates people to engage in healthy and unhealthy behaviors. These theories vary, and can be grouped according to value-expectancy approaches, risk-oriented theories, social cognitive theory, and stage theories. Keywords: health behavior; health communication; health lifestyles; health psychology; health risks
Defects in mismatch repair promote telomerase-independent proliferation

Mismatch repair has a central role in maintaining genomic stability by repairing DNA replication errors and inhibiting recombination between non-identical (homeologous) sequences. Defects in mismatch repair have been linked to certain human cancers, including hereditary non-polyposis colorectal cancer (HNPCC) and sporadic tumours. A crucial requirement for tumour cell proliferation is the maintenance of telomere length, and most tumours achieve this by reactivating telomerase. In both yeast and human cells, however, telomerase-independent telomere maintenance can occur as a result of recombination-dependent exchanges between often imperfectly matched telomeric sequences. Here we show that loss of mismatch-repair function promotes cellular proliferation in the absence of telomerase. Defects in mismatch repair, including mutations that correspond to the same amino-acid changes recovered from HNPCC tumours, enhance telomerase-independent survival in both Saccharomyces cerevisiae and a related budding yeast with a degree of telomere sequence homology that is similar to human telomeres. These results indicate that enhanced telomeric recombination in human cells with mismatch-repair defects may contribute to cell immortalization and hence tumorigenesis.
Reexamining the consumption smoothing benefits of Unemployment Insurance

Abstract The Great Recession spurred renewed interest in the moral hazard effects of the Unemployment Insurance (UI) program, however little research has focused on determining its benefits. This paper examines the consumption smoothing benefit of the UI program over the last 40 years, finding strong evidence of heterogeneity in this effect over time. In particular, the effects of UI are smaller in the 1990s compared with the 1970s. The 1990s were unique because of the long period of low unemployment rates as well as relatively low UI program generosity, thus we test whether the consumption smoothing effects vary by the state unemployment rate and average program generosity. We find suggestive evidence that the effects are larger when the state unemployment rate and average generosity are high. Together, these two dimensions can explain around 30–46% of the differential effect that we find in the 1990s.
Synthetic ultra-wideband antenna for high-resolution millimeter-wave imaging

A synthetic ultra-wideband millimeter-wave antenna with application in high-resolution millimeter-wave imaging systems is presented. The antenna provides a synthetic ultra-wide bandwidth of approximately 100 GHz in the millimeter-wave regime. Our approach consists of dividing the assumed ultra-wide bandwidth (20–120 GHz) into four channels or sub-bands, and designing an antenna array including four antennas (equal to the number of sub-bands). The antennas are substrate integrated waveguide (SIW)-based antipodal Vivaldi antennas covering 20–40 GHz, 40–60 GHz, 60–90 GHz, and 90–120 GHz frequency ranges respectively. The achieved ultra-wide bandwidth (100 GHz) results in a significant improvement in the axial resolution of current millimeter-wave imaging systems.
Heavy Quark Masses and Duality

Duality is formulated using flavor-separatede+e− annihilation moments sum rules. We determine the quark production cross section dual to the hadronic annihilation data for thec−c sector and find the charm quark mass to bemc=1.47±0.05 GeV.
Effects of Brewers’ condensed solubles (bcs) on the production of ethanol from low-grade starch materials

Yeast fermentation was performed on grain and bakery byproducts with and without adding the same volume of brewers’ condensed solubles (BCS). Starch material in the grain and bakery byproducts effectively was converted to fermentable sugars with conversion ratios of 93–97% by successive treatments of samples with bacterial αamylase and fungal glucoamylase. The yeast fermentation of these enzyme-digested byproducts alone showed that ethanol concentrations of 16.4–42.7 mL/100 g dry solid in the broth were achieved with fermentation efficiencies of 87–96%. Addition of BCS to the grain byproducts increased ethanol concentration by 10–86% by increasing the potential glucose content of the broth. The rates of fermentation measured by CO2 gas production demonstrated that BCS addition to bakery byproducts reduced the fermentation time from 62–72 h to 34–35 h. In bakery byproducts that were low in amino nitrogen, exhaustion of nitrogenous compounds in substrates was found to be a limiting factor for yeast growth. Because BCS is a rich source of nitrogen, adding BCS to these substrates markedly increased the fermentation rate.
Infectious disease challenges in immigrants from tropical countries.

Background. In today9s mobile society, international travel and immigration are becoming increasingly more common. This poses an additional challenge to the clinician to expand the differential diagnosis to include diseases endemic to the area of travel. Observation. We present a case of malaria and tuberculosis in a 16-year-old African male immigrant. He had several encounters with the health care system for complaints of nonspecific symptoms for which he was treated with antibiotics without follow-up. Conclusion. Clinicians should take a complete history and expand their differential diagnosis to include diseases endemic to the country of origin and/or travel when treating an international patient. This not only will allow prompt treatment of the patient9s condition but also will address public health concerns.
The influence of prior strain rate on stress relaxation in solder alloys

Abstract The prior deformation history-dependence of the stress relaxation behavior of 60Sn–40Pb, 96Sn–4Ag, and 96.2Sn–2.5Ag–0.8Cu–0.5Sb (Castin™) is investigated. In new experiments, stress relaxation was measured immediately after three different applied strain rates: 10 −3 , 10 −4 , and 10 −5 s −1 . These tests revealed the unexpected result that the different prior deformation histories imposed affect the observed relaxation behavior such that higher strain rates during prior deformation result in greater total stress relaxation as well as lower relaxed stress. The McDowell model with a rate-dependent limiting value for short-range kinematic hardening predicts the stress relaxation behavior. Though the model predicts flow stress well during strain rate jump test simulations, it tends to over-predict the material response during the transient response just after each jump in strain rate. In another exercise, the inclusion of a rate-dependent isotropic hardening relation in the model does not improve the transient response of the model during strain rate jump simulations and simulates other material behavior that is not observed in the experimental data.
Narrowing the linewidth to a desired value with a reflecting volume-Bragg-grating (RVBG) for high-powered LDs

In recent years, reflecting volume-Bragg-gratings (RVBGs) have been considered as the perfect elements to narrow the spectrum with highly adjustable parameters. In fact, the effects of narrowing the linewidth of high-powered LDs are determined by the parameters such as the grating thickness, refractive index modulation, and grating spatial frequency. By use of the theoretical regime, the relationships between the effective diffraction efficiency and these parameters of a RVBG have been systematically investigated to narrow the linewidth to a desired value. Although the results reveal that a higher effective diffraction efficiency may be achieved by adopting three parameters mentioned above with higher values, by considering the difficulties and confinement in production process of a RVBG, the characteristic parameters should be carefully selected as some appropriate values. From the evaluation, one also understands that the narrow linewidth of a RVBG-coupled LD and the high effective diffraction efficiency cannot be arbitrarily realized at the same time for a real case. The conclusions are thought to be valuable in construction of a practical narrow linewidth LD system.
Formaldehyde ferredoxin oxidoreductase from Pyrococcus furiosus: the 1.85 A resolution crystal structure and its mechanistic implications.

Crystal structures of formaldehyde ferredoxin oxidoreductase (FOR), a tungstopterin-containing protein from the hyperthermophilic archaeon Pyrococcus furiosus, have been determined in the native state and as a complex with the inhibitor glutarate at 1.85 A and 2.4 A resolution, respectively. The native structure was solved by molecular replacement using the structure of the homologous P. furiosus aldehyde ferredoxin oxidoreductase (AOR) as the initial model. Residues are identified in FOR that may be involved in either the catalytic mechanism or in determining substrate specificity. The binding site on FOR for the physiological electron acceptor, P. furiosus ferredoxin (Fd), has been established from an FOR-Fd cocrystal structure. Based on the arrangement of redox centers in this structure, an electron transfer pathway is proposed that begins at the tungsten center, leads to the (4Fe:4S) cluster of FOR via one of the two pterins that coordinate the tungsten, and ends at the (4Fe:4S) cluster of ferredoxin. This pathway includes two residues that coordinate the (4Fe:4S) clusters, Cys287 of FOR and Asp14 of ferredoxin. Similarities in the active site structures between FOR and the unrelated molybdoenzyme aldehyde oxidoreductase from Desulfovibrio gigas suggest that both enzymes utilize a common mechanism for aldehyde oxidation.
LEVELS OF SUBNORMALITY

Abstract Three progressively more stringent constraints are added to the requirement that a matrix be subnormal for the case that A is normal. This results in the definition of four classes of subnormal matrices. Two of these classes are categorized, and it is shown by way of examples and counterexamples that these four classes are nontrivial and distinct.
Spraying potatoes to prevent leaf roll spread by the green peach aphid

Studies were made at Presque Isle, Maine, 1962–1966, to determine the suppressive effects of several materials against spread of the potato leaf roll cirus,Corium solani Holmes, transmitted by the green peach aphid,Myzus persicae (Sulzer), when applied as foliar sprays to Kennebec, Green Mountain, or Chippewa potatoes in field cages or in field plots. The early cage tests showed that spray mixtures containing 1% of the systemic plant growth regulant chlorocholine chloride (2-chloroethyltri-methylammonium chloride) or 1% of mineral oil were more effective than the insect antifeeding compound AC-24,055® (=ENT-25,651), the aphid-repellent compounds ENT 20,430 or ENT 21,178, or the surfactants Sarkosyl-O® (bis (2-ethylhexyl) sodium sulfosuccinate) or Aerosol-OT® (CH3 (CH2)n CON (CH3) CH2 COOH). Field tests disclosed that chlorocholine chloride at 5.2 lb or 2.6 lb/a/a was more effective when healthy green peach aphids were placed on infector plants in the plots soon after the plants were sprayed, 1 week later, or soon after the 2nd of 2 weekly applications than when the aphids were introduced before spraying. The difference in leaf roll suppression at these two dosages was not significant at the 5% level; as high as 90% control of leaf-roll spread was obtained. When only natural infestations of aphids were involved and field spread of the virus was light, the 86% control of leaf roll spread that was obtained from 4 weekly applications made in late June and in July was not significantly different (P=0.05) from the 79% control obtained from 2 biweekly applications made during the same period of time. The potato plants soon recovered from the slight chlorosis resulting from the spray treatment and there was no reduction in weight of US 1 tubers at harvest. Aphid population trends in treated plots were not affected.
Caffeine exposure alters cardiac gene expression in embryonic cardiomyocytes.

Previous studies demonstrated that in utero caffeine treatment at embryonic day (E) 8.5 alters DNA methylation patterns, gene expression, and cardiac function in adult mice. To provide insight into...
Damage Detection in Satellite Bolted Joints

To overcome current limitations of satellite operation timelines, Operationally Responsive Space (ORS) satellites are being developed for rapid configuration and assembly. Time spent on flight qualification tests aimed at assembly verification and launch vehicle integration must be reduced to less than a week. Structural health monitoring (SHM) is seen as a possible avenue for real-time assessment of satellite integrity and qualification before launch. Embedded ultrasonics and magneto-mechanical impedance (MMI) were considered as potential candidates for diagnostics of critical system elements. Piezoelectric wafer active sensors in conjunction with an acousto-elastic SHM were used for assessment of aerospace structures with bolted joints. In the presented analysis, the acousto-elastic behavior of the joint was used as an indicator of structural integrity. Experimental results show changes in the nonlinear response of joints as a result of differing bolt torque. Localization potential of the acousto-elastic technique was demonstrated in a complex structure analogous to a typical satellite panel. The MMI method has shown utility in assessing condition of bolted joints in thin plates and a satellite structure. Experimental data reveal changes in magnitude and position of impedance peaks induced by the difference in structural loads applied to the joint. It is suggested that both the acousto-elastic and MMI methods have indicated possibilities for detecting and characterizing damage in satellite bolted joints.Copyright © 2008 by ASME and US Government
On First Cycle Slip Time of Phase-Locked Loops in Cascade

Precise measurement and spacecraft tracking are obtained by using phase-locked loops in cascade in two-way communications links. Statistics on cycle slip time are of vital importance in system planning and design. This paper presents: 1) results of a computer simulation study of the mean time to first cycle slip of cascade phase-locked loops preceded by bandpass limiters, and 2) the determination of probability distributions of cycle slip. Numerical results are obtained for a typical coherent communication system.
The secreted metalloprotease ADAMTS20 is required for melanoblast survival.

ADAMTS20 (A disintegrin-like and metalloprotease domain with thrombospondin type-1 motifs) is a member of a family of secreted metalloproteases that can process a variety of extracellular matrix (ECM) components and secreted molecules. Adamts20 mutations in belted (bt) mice cause white spotting of the dorsal and ventral torso, indicative of defective neural crest (NC)-derived melanoblast development. The expression pattern of Adamts20 in dermal mesenchymal cells adjacent to migrating melanoblasts led us to initially propose that Adamts20 regulated melanoblast migration. However, using a Dct-LacZ transgene to track melanoblast development, we determined that melanoblasts were distributed normally in whole mount E12.5 bt/bt embryos, but were specifically reduced in the trunk of E13.5 bt/bt embryos due to a seven-fold higher rate of apoptosis. The melanoblast defect was exacerbated in newborn skin and embryos from bt/bt animals that were also haploinsufficient for Adamts9, a close homolog of Adamts20, indicating that these metalloproteases functionally overlap in melanoblast development. We identified two potential mechanisms by which Adamts20 may regulate melanoblast survival. First, skin explant cultures demonstrated that Adamts20 was required for melanoblasts to respond to soluble Kit ligand (sKitl). In support of this requirement, bt/bt;Kittm1Alf/+ and bt/bt;KitlSl/+ mice exhibited synergistically increased spotting. Second, ADAMTS20 cleaved the aggregating proteoglycan versican in vitro and was necessary for versican processing in vivo, raising the possibility that versican can participate in melanoblast development. These findings reveal previously unrecognized roles for Adamts proteases in cell survival and in mediating Kit signaling during melanoblast colonization of the skin. Our results have implications not only for understanding mechanisms of NC-derived melanoblast development but also provide insights on novel biological functions of secreted metalloproteases.
Age-related changes in climbing behavior and neural circuit physiology in Drosophila

Identifying the cellular and molecular basis for functional decline remains key to understanding aging. To this end, we have characterized age-dependent changes in climbing and the electrophysiology of the giant fiber circuitry in wild type (Wt) and mutant flies with altered lifespan (methuselah and fragile-X). Our data demonstrate a gradual decline in climbing in Wt and methuselah flies aged 5-45 days. In contrast, fragile-X flies climbed poorly even at 5 days and failed completely at 45 days. We then examined whether synaptic transmission to indirect flight muscles along the giant fiber circuit was altered with aging. At 5 days, the dorsal longitudinal muscle (DLM) in Wt flies followed high frequency stimulation well (at 130 Hz or above). At 35 and 45 days, these flies only followed 60-80 Hz. Methuselah flies did not follow stimuli as well as the Wt flies did at 5 and 25 days, but they were similar to Wt flies at older ages. Fragile-X flies responded poorly even at 5 days (40 Hz) and worsened at 35 days (30 Hz). Unlike DLMs, the tergotrochanteral muscle followed high frequency stimuli relatively well in all genotypes, suggesting that the peripheral interneuron along the DLM pathway or the DLM muscular synapse is prone to age-dependent functional decline. These studies reveal subcellular structures as potential targets of aging, indicating that the giant fiber pathway can be used as a model circuit for quantitative studies of aging in flies as well as fly models of age-related human neurological disorders.
CHUNK: An Agile Approach to the Software Development Life Cycle

ABSTRACT This article introduces a methodology for developing applications incorporating components of Agile development methods with the traditional software development life cycle (SDLC), a.k.a. the “waterfall” model of software development. We look at the causes for failure of software development projects and propose steps in the development process to address many of the root causes of these failures (it would be implausible to state that any development methodology could eliminate the risk of failure). We also provide a critical review of Agile principles and the traditional SDLC. The steps of the new methodology are then described with rationalization for their necessity.
Gender and suicide risk among artists: a multivariate analysis

Research on mental disorders among male artists has suggested that artists are at risk of suicide. However, given that men are higher in suicide risk than women, the presumed suicide risk of artists may be an artifact of sampling bias. A logistic regression analysis of data from 21 states finds that artists have 270% higher risk of suicide than nonartists. However, after controlling for gender and sociodemographic variables, this risk level is reduced to 125%. The findings are related to both psychiatric and work-related stress factors that may place artists at risk of suicide as an occupational group.
Digitizing the Sedimentary Record: Efficient Data Structures for Dynamic Stratigraphy

As the surface of the Earth evolves over geologic time sediment is transported from high mountains to low lying sedimentary basins, accumulating stratigraphy which stores a sedimentary record of past environments. Understanding the structure of this stratigraphy is essential for exploiting sub-surface resources such as oil and water, and for deciphering the sedimentary record. Sophisticated computational models of Earth-surface dynamics can be used to predict formation of stratigraphy, but require stratigraphy in a discrete form. Here I present a discrete stratigraphic data structure which enables simulation of dynamic stratigraphic evolution. The data structure is robust and efficient, but can be easily coupled to existing Earth-surface dynamics models with minimal effort due to a simple interface. This represents a significant advance which will allow widespread use of dynamic models to predict and invert stratigraphy for application in a variety of fields.
Studies on the disulfide bonds in human pituitary follicle-stimulating hormone.

Abstract Human follicle-stimulating hormone (FSH) was digested with subtilisin, thermolysin, cyanogen bromide, pronase and trypsin to isolate the cystine-containing peptides. These peptides were purified by gel filtration through Sephadex G-50 column and by high-voltage paper electrophoresis at pH 6, 3.5 and/or 2. The location of the cystine-containing peptides in human FSH α- and β-subunits was established by amino acid composition, end-group analysis and determination of the amino acid sequence by Edman degradation. The results indicate that the disulfide bonds are present between half-cystine residues located between positions 7 and 10, 28 and 87 and 82 and 84 in the α-subunit, and between positions 3 and 28, 17 and 51 and 32 and 104 in the β-subunit of human FSH.
3′ End structure and rearrangements of EGFR in glioblastomas

Rearrangements of EGFR are known to occur in a significant fraction of glioblastomas, the most common and malignant form of central nervous system tumor. Although the consequences of these alterations have been described at the mRNA and protein level, little is known about human EGFR genomic sequence or organization at the rearrangement sites. To investigate one group of alterations in glioblastoma, we used long-range PCR to synthesize a segment of the gene near its 3' end, which is frequently rearranged in tumors with EGFR amplification. The sequence of this PCR product provided a precise map for the five 3'-terminal exons of EGFR, designated as exons 22-26. Ten tumors were identified with rearrangements in this part of the gene, most of which resulted in the loss of 325 coding bases that constitute exons 23-25. No two tumors shared identical donor or acceptor rearrangement sites, and the examination of sequences at these sites failed to support homologous recombination as a mechanism responsible for any of the rearrangements. However, examination of the entire exon 22-26 region for sequence motifs associated with genomic instability identified two large, CA-rich tracts in intron 25.
Infection of the western treehole mosquito, Aedes sierrensis (Diptera: Culicidae), with Lambornella clarki (Ciliophora: Tetrahymenidae)

Abstract Lambornella clarki was a common parasite of Aedes sierrensis immatures collected from treeholes in Mendocino County, California, in 1982–1983. The ciliate was not found in mosquitoes from treeholes with water having the most extreme values of electrical conductivity ( 1.74 mmhos/cm) and pH ( 7.7). Infection rates for individual monthly samples from L. clarki-positive treeholes ranged from 1 to 75%; 67% of all infections were observed in 4th-instar larvae. Infection with pathogens and parasites such as L. clarki, Ascogregarina clarki, Octomyomermis troglodytis, and unidentified bacteria and fungi, appeared responsible for high mortality rates (21–76%). Parasitism with L. clarki did not always result in death of the mosquito host; 7% of adults emerging from samples held in the laboratory were found to be infected. Ciliates were restricted to the host hemocoel except in older females where they invaded the ovaries, resulting in parasitic castration. This phenomenon may be associated with parasite dispersal.
Undersurface Tear of the Ulnar Collateral Ligament in Baseball Players A Newly Recognized Lesion

Seven patients were diagnosed with an undersurface tear of the deep capsular layer of the anterior bundle of the ulnar collateral ligament. Preoperatively, all of the patients had tenderness over the anterior bundle of the ulnar collateral ligament and pain with valgus stressing of the elbow. Six of the seven patients had a normal magnetic resonance imaging scan, with one magnetic resonance imaging scan showing degeneration within the ligament. All of the patients had a negative computed tomography arthrogram for extracapsular contrast extravasation. A consistent finding in five of the seven patients was a leak of contrast around the edge of the humerus or ulna, although the contrast was contained within the joint. At arthroscopic evaluation, all of the patients demonstrated medial elbow instability as valgus stress was applied across the elbow joint in 70 degrees of flexion. All of the patients underwent open medial elbow surgery, where the ulnar collateral ligament was visualized and found to be intact externally. But when the anterior bundle was incised, there was a detachment of the undersurface of the ligament at the ulna or the humerus. Cadaveric dissections were performed to define the anatomy of the insertion sites and to confirm that this lesion was not an anatomic variant. A tear of the deep layer of the ulnar collateral ligament can result in symptomatic instability that is difficult to diagnose with conventional preoperative testing. This lesion of the anterior bundle of the ulnar collateral ligament has not been previously reported, and in our series it was associated with persistent medial elbow pain in throwing athletes.
Evaluation of spindle cell tumors

The most important aspect of any evaluation of spindle cell tumors in the skin or superficial soft tissues is the clinical examination, as a great deal can be learned from the location, appearance, and size of the tumor in question. As recounted in this chapter, the histologic features of these tumors may also be distinctive; however, in some instances, histologic examination alone is insufficient for diagnosis. In such cases, electron microscopy holds considerable promise, but the technique is too dependent upon both the availability of adequately preserved tissues and access to the technique itself. As a result, immunohistochemistry remains the favored approach to most problematic lesions. In our experience, at least 90% of histologically enigmatic tumors will exhibit a characteristic immunophenotype, the remainder usually being indeterminant for a specific pattern of differentiation. The latter outcome is often the result of improper tissue preservation, but may also reflect the primitive nature of some neoplasms. Fortunately, the least common outcome is an ambiguous or "mixed-lineage" phenotype, in which neither one of two or more patterns of differentiation is resolved with certainty. The most common settings in which these problems arise are the separation of MPNST from LMS, and the recognition of melanocytic lesions as distinct from tumors of peripheral nerve sheath. The latter is clearly of greatest clinical concern, and should be the focus of additional study.
A TASK PLANNER FOR INTELLIGENT MOBILE ROBOTS USING SUBGOAL PRIORITY INFORMATION

We have developed a fast task planner for intelligent mobile robots. The speed gain of this task planner over traditional task planners is achieved by avoiding goal-interaction and by utilizing a parallel comparison network. Goal-interaction during task planning is avoided by executing subgoals in a depth first fashion according to the priority numbers attached to subtasks and preconditions of the robot operations in the rule base. The assignment of these priority numbers is based on spatial relationship between objects in the robot environment and time sequence of the subtasks. A combination of hardware circuits and software program is used to search proper robot operations in parallel. Special problems encountered in the design of this task planner are discussed and examples are given to demonstrate the advantages of this task planner. This study provides a new approach which significantly increases the speed of robot task planning.
Aerodynamically and Structurally Coupled Vibration of Multiple Co-Rotating Disks

This paper studies vibration of multiple, co-rotating, identical disks coupled by air flow and structural flexibility. In particular, the study focuses on coupled vibration of disk modes with two or more nodal diameters. First, frequency response functions of multiple co-rotating disks are measured in air and in vacuum to study the effects of aerodynamic coupling. In vacuum, vibration modes from each rotating disk are aerodynamically uncoupled; therefore, corresponding travelling waves from each disk have the same natural frequency. When the air is present, the air couples the corresponding travelling waves and rearranges them into a group of N traveling waves with distinct frequencies, where N is the number of the disks. A perturbation analysis is developed to prove the phenomenon of frequency splitting. Aside from the air coupling, finite element analyses and experimental measurements indicate that the flexibility of the clamp and spacers between the disks can also couple the disk vibration in the same manner Moreover, the aerodynamic coupling is more significant for disk modes with high number of nodal diameters (e.g., 4-nodal-diameter modes). In contrast, structural coupling through spacer flexibility is more pronounced for disk modes with low number of nodal diameters (e.g., 2-nodal-diameter modes). Also, parametric studies using FEA indicate that frequency splitting from structural coupling will remain significant over a wide parameter range.
A review of experimental studies of knock chemistry in engines

Abstract Early engine research related to the chemistry of knock produced results which complement and support modern work and, in many cases, provide intriguing data against which modern concepts and models of knock can be compared. This article presents a chronological summary of research in motored and fired engines conducted to understand the chemical processes associated with knock. Further, it attempts to highlight the superior and intriguing aspects of these works. Four basic research areas are covered: fuel effects, including fuel structure, additives and pre-oxidation, pre-combustion heat release, spectroscopic investigations and rapid sampling valve research.