cssi/SciSciGPT-SciSciNet huggingface dataset:
Update in endocrinology: evidence published in 2014.

This Update summarizes studies published in 2014 that the authors consider highly relevant to the practice of endocrinology. Topics include diabetes and obesity, lipid management, bone metabolism, ...
Time Delay Aeroelastic Feedback Control of 2-D Lifting Surfaces

Two basic issues related to the open/closed loop aeroelasticity of 2-D lifting surfaces in an incompressible flow field are considered in this paper. These concern the subcritical aeroelastic response to external time-dependent excitations, and the flutter instability of actively controlled airfoils involving a delayed feedback control. Results and comparisons regarding the flutter instability obtained via the first Volterra kernel in conjunction with a frequency eigenvalue analysis are presented. In the same context, the implications of the presence of time delays in the feedback control on the instability boundary and aeroelastic response are investigated and pertinent conclusions are supplied.Copyright © 2002 by ASME
Human Origins: It began in Africa

A mountain of evidence has accumulated showing that our ancestors emerged in Africa. What is less clear-cut is what spurred their evolution
Reaction-based small-molecule fluorescent probes for chemoselective bioimaging

The dynamic chemical diversity of elements, ions and molecules that form the basis of life offers both a challenge and an opportunity for study. Small-molecule fluorescent probes can make use of selective, bioorthogonal chemistries to report on specific analytes in cells and in more complex biological specimens. These probes offer powerful reagents to interrogate the physiology and pathology of reactive chemical species in their native environments with minimal perturbation to living systems. This Review presents a survey of tools and tactics for using such probes to detect biologically important chemical analytes. We highlight design criteria for effective chemical tools for use in biological applications as well as gaps for future exploration.
Characterization of aluminium-matrix composites made by compocasting and its variations

Compocasting (semisolid-semisolid, SS) and its two variations: SL (semisolid-liquid) and LL (liquid-liquid) process routes are used to make 2024Al reinforced with 3 mm and 12 mm long FP-alumina fibres. Squeeze-casting is used as a complementary casting technique. The effect of processing route on microstructure and the mechanical properties of these composites is studied. The SS route produces composites with uniform fibre distribution, but casting is difficult due to the high viscosity of the slurry. The SL route gives good fibre distribution and the casting is easy. The LL route allows addition of a large amount of fibres but gives castings with a non-uniform fibre distribution, which lowers the failure strains and reduces the strength of the composites drastically. The addition of alumina fibres to 2024Al increases its modulus of elasticity considerably. The observed modulus values show good agreement with the theoretical predictions. The strength values are somewhat lower than the theoretical predictions. This is because the composites failed at strains slightly lower than the fibre failure strain. Absence of fibre pull-out indicates that a good fibre matrix bond has been produced in each case.
Tropical atmospheric circulation and precipitation changing

[1] As Earth's climate has warmed over the past several decades, atmospheric and hydrological cycle changes are being observed globally and regionally. For instance, Zhou et al. analyzed trends in the hydrological cycle in the tropics over the past 20–30 years using precipitation, cloud, and radiation data. In particular, the researchers looked at Hadley and Walker cell atmospheric circulation patterns. Hadley circulation is a major circulation pattern in the tropical atmosphere in which air masses, warmed by the Sun, rise near the equator, then travel poleward, sink back toward Earth's surface in the subtropics, and return to the equator. Similarly, in the Walker circulation, air rises over the warmer parts of the oceans near the equator, travels zonally toward the colder parts, then sinks back to the surface. There are indications that both of these circulation patterns are changing with global warming and could be altering precipitation and cloud radiation distributions in the tropical regions. (Journal of Geophysical Research-Atmospheres, doi:10.1029/2010JD015197, 2011)
Unsharp degrees of freedom and the generating of symmetries

In quantum theory, real degrees of freedom are usually described by operators which are self-adjoint. There are, however, exceptions to the rule. This is because, in infinite dimensional Hilbert spaces, an operator is not necessarily self-adjoint even if its expectation values are real. Instead, the operator may be merely symmetric. Such operators are not diagonalizable - and as a consequence they describe real degrees of freedom which display a form of "unsharpness" or "fuzzyness". For example, there are indications that this type of operators could arise with the description of space-time at the string or at the Planck scale, where some form of unsharpness or fuzzyness has long been conjectured. A priori, however, a potential problem with merely symmetric operators is the fact that, unlike self-adjoint operators, they do not generate unitaries - at least not straightforwardly. Here, we show for a large class of these operators that they do generate unitaries in a well defined way, and that these operators even generate the entire unitary group of the Hilbert space. This shows that merely symmetric operators, in addition to describing unsharp physical entities, may indeed also play a r{o}le in the generation of symmetries, e.g. within a fundamental theory of quantum gravity.
Genetic analyses of wild populations of Hawaiian geese using DNA fingerprinting

DNA fingerprinting was used to compare levels of genetic variation among 75 wild Hawaiian Geese, or Nene (Branta sandvicensis), from six populations on the islands of Hawaii, Maui, and Kauai and between the six wild populations and a captive colony of 29 Nene. Mantel tests were used to determine differences in similarity coefficient distributions (amount of genetic similarity among individuals within each population) among wild Nene and between wild and captive Nene. Nene from Hawaii Volcanoes National Park on the island of Hawaii bad the lowest similarity coefficient distribution, whereas Nene on Kauai had the highest. Captive birds had an intermediate similarity coefficient distribution when compared to wild populations. No unique DNA fingerprint fragments were found in wild birds when compared to captive birds. Successful recruitment of migrants might have decreased similarity at Hawaii Volcanoes National Park, whereas inbreeding and captiverelease techniques might have increased similarity on Kauai. Varying levels of inbreeding or fixation by drift might explain differences in similarity coefficient distributions between wild and captive populations
Phosphate supplements in experimental fractures.

Abstract 1. 1. Rats fed a high-phosphorus diet showed no statistically significant differences in tensile strength of standardized fibula fractures when compared to controls at similar time intervals after fracture. 2. 2. Preliminary histochemical studies showed more rapid maturation of fracture callus to compact bone in the group fed a high-phosphorus diet.
On the applicability of the Aristotelian principles to the definition of life

Despite numerous attempts, we still do not have a satisfactory definition of life. It is generally accepted that one of the essential features of life is the ability of an organism to reproduce. This implies that mules, workers ants, and other sterile individuals are not alive. To correct this apparent problem, we suggest that life should be defined in two ways. First, we define life as a phenomenon, for which the reproduction of some, but not all, individuals is essential. Second, we define life as a set of characteristics of an individual organism, among which reproduction is not essential. We explore Aristotle's classifications of things that exist, in which he placed individual living beings as primary substances, above their species and genera, which are considered secondary substances. The definition of life as a phenomenon needs to link life to its origins. Life presumably emerged from abiotic matter via chemical evolution. We have examined Aristotle's concept of change in which potentiality goes to actuality, and its variant, Kauffman's concept of ‘adjacent possible’, for their possible application in prebiotic chemical evolution. We have found that these principles are somewhat useful in the back-engineering process, but that they have very little predictive value. We have also considered whether viruses should be considered alive, and have pointed to the need for astrobiology to include viruses in its studies.
Effect of planting depth and hilling practices on total, U.S. No. 1, and field greening tuber yields

Previous research suggests that field greening of potato tubers can be minimized by planting seedpieces at an appropriate depth along with sufficient hilling to minimize exposure to sunlight. The appropriate planting depth and hilling practices to minimize field tuber greening have not been determined for newer cultivars. Two separate studies, each conducted for three years, are reported here. The first measured the effect of seedpiece planting depth on the yield, quality, and field greening tuber yield of ‘Russet Burbank’, ‘Frontier Russet’, and ‘Shepody’ potatoes. Seedpieces were handplanted in pre-formed hills at 8, 15, or 23 cm measured from the top of the seedpiece to the top of the hill. Planting at 23 cm resulted in significantly lower total yield compared with the 8- and 15-cm depths for Russet Burbank and Frontier Russet, but planting depth did not affect total yield of Shepody. U.S. No. 1 yield of Russet Burbank was not affected by planting depth, but U.S. No. 1 yield of Frontier Russet was significantly less at the 23-cm depth. For Shepody, the 8-cm depth caused a significant reduction in U.S. No. 1 yield compared with the 15-cm depth. Field greening tuber yield of Russet Burbank was significantly less at the 23-cm planting depth compared to 8 cm. For Frontier Russet and Shepody, planting at 15 or 23 cm resulted in significantly less field tuber greening compared to the 8-cm depth.
Mechanism of Self-Tolerance and Events Leading to Autoimmune Disease and Autoantibody Response

This review summarizes recent studies on the mechanisms of self-tolerance and autoimmune disease pathogenesis based primarily on the murine ovarian autoimmune disease models. The ovarian autoimmune disease was induced experimentally by three approaches: (1) transfer of normal T cells into syngeneic athymic nu/nu mice, (2) neonatal thymectomy, or (3) immunization with a well-defined peptide from the ovarian antigen, ZP3. Self-reactive T cells with capacity to elicit autoimmune oophoritis and autoimmune gastritis are not deleted in the neonatal or adult thymus. In the adult spleen, T cells are not pathogenic until regulatory T cells have been depleted. Thus the balance of activity between pathogenic T cells and regulatory T cells appears to determine the tolerance status of the host to self-antigens responsible for these autoimmune diseases. Murine autoimmune disease of the ovaries was found to occur through two independent pathways. The first is by depletion of regulatory T cells, as created by thymectomy within 4 days after birth. Alternatively, pathogenic T cells can be activated through molecular mimicry at the level of T cell peptide. This appears to depend on the sharing between non-ovarian and ovarian peptides of critical amino acid residues required for activation of pathogenic T cells. Finally, when T cells that recognize the ZP3 peptide are activated, endogenous ovarian antigens can spontaneously stimulate B cells to produce antibodies that react with ZP3 domains outside the immunizing T cell peptide.
Recent Stratospheric Climate Trends as Evidenced in Radiosonde Data: Global Structure and Tropospheric Linkages

The global structure of recent stratospheric climate trends is examined in radiosonde data. In contrast to conclusions published in previous assessments of stratospheric temperature trends, it is demonstrated that in the annual mean the tropical stratosphere has cooled substantially over the past few decades. The cooling of the tropical stratosphere is apparent in both nighttime and adjusted radiosonde data, and seems to be robust to changes in radiosonde instrumentation. The meridional structure of the annual-mean stratospheric trends is not consistent with our current understanding of radiative transfer and constituent trends but is consistent with increased upwelling in the tropical stratosphere. The annual-mean cooling of the tropical stratosphere is juxtaposed against seasonally varying trends in the extratropical stratosphere dominated by the well-known springtime cooling at polar latitudes. The polar stratospheric trends are accompanied by similarly signed trends at tropospheric levels in the Southern Hemisphere but not in the Northern Hemisphere.
Characteristics of an MM 22 medical microtron 21 MV photon beam.

Abstract Beam quality, surface doses, depths of maximum dose, peak dose rates, beam profiles, and central axis percentage depth doses of a medical microtron's 21 MV photon beam were measured. The half-value layer of lead was 1.35 cm, the half-value layer of water was 23 cm, and the nominal acceleration potential was 17.7 MV. For a 10 × 10 cm 2 field at 100 cm SSD, the maximum dose occurred at a depth of 3 g · cm −2 and the surface dose was 18% of the maximum. The highest dose rate at isocenter was approximately 800 cGy·min −1 . The worst horns on beam profiles occurred at a depth of 5 cm for the 35 × 35 cm 2 field where the dose rate 4 cm from the edge of the beam was 3% higher than that on the central ray. No horns were apparent for fields 25 × 25 cm 2 or smaller.
Broadband circular polarizer formed by stacked plasmonic metasurfaces

Recent ideas involving plasmonic metamaterials have been put forward to enhance the overall bandwidth of operation of quarter-wave plates for circular polarization detection. The proposed metamaterial geometries are inherently complex to realize and difficult to scale beyond the near-infrared frequencies. Here, we show how proper stacks of lithographically printed plasmonic metasurfaces with simple patterns may provide large extinction ratios for the detection of circular polarization, combined with broadband operation and simplicity of design and realization. In this paper, we will discuss some physical insights into the modeling of these structures, fundamental advantages and some limitations of this approach.
Suprachiasmatic nucleus grafts restore circadian function in aged hamsters

Abstract The regulation of circadian rhythms changes with age. In humans, changes in the timing of sleep and wakefulness are especially common. In Syrian hamstersMesocricetus auratus the freerunning period of the activity/rest rhythm shortens with age. The present study tested the hypothesis that critical age-related changes occur within the hypothalamic suprachiasmatic nucleus (SCN), known to contain a circadian pacemaker. Fetal SCN were transplanted into the brains of younger (20 weeks) and older (81 weeks) hamsters which had had their own SCNs ablated. The restoration of rhythmicity and the freerunning period of the rhythmicity were determined from continuous records of wheel-running activity. Transplantation restored rhythmicity in hosts of both ages. In older hamsters, the mean freerunning period after transplantation was longer than that measured before SCN ablation, but a similar lengthening of period was not observed after transplantation to younger hamsters. In addition, the mean period after transplantation was the same for both younger and older hosts even when there was a difference between the groups before SCN ablation. When the grafts were allowed to age, the mean freerunning period of the restored rhythms became shorter, indicating that the grafts can also undergo age-related changes. The results indicate that age-related changes specifically in the SCN are responsible for an age-related change in freerunning period.
A new quality check for absolute palaeointensities of the Earth magnetic field

Absolute palaeointensity determinations of recent lavas from Mt. Etna have been carried out using the Koenigsberger-Thellier-Thellier (KTT) method but with two different data presentations. The first, which is the standard method, compares the natural remanent magnetization (NRM) demagnetized and the thermoremanent magnetization (TRM) acquired in successive temperature intervals cumulatively. The second compares the NRM and TRM in the successive intervals in an incremental manner. The latter method appears to distinguish aberrant behaviour better than the classical method. Such aberrant behaviour can be related to changes in hysteresis ratio parameters, saturation remanent magnetization to saturation magnetization and remanent coercive force to coercive force, which are reflected by displacements in the Day et al. (1977) plot. These changes in hysteresis parameters are caused by irreversible changes in domain state or transformations of magnetic phases brought about by the thermal cycling. The changes in hysteresis parameters serve as a useful quality factor for absolute palaeointensity determinations.
Efficient proper 2-coloring of almost disjoint hypergraphs

Let A be an n-uniform hypergraph. Assume that the maximum degree of A is D = D(A) (local condition), and |A| = N = N(A) (global condition). By the Lovasz Local Lemma (L.L.L.), if D
“Touched” by Light: Event-Related Potentials (ERPs) to Visuo-Haptic Stimuli in Peri-Personal Space

Parietal neuronal populations have been found which respond bimodally to visual and somatosensory input regarding one’s own limbs or even perceived haptic input of a false limb (Graziano et al., Science 290:1782–1785, 2000). Further, neuronal populations have been observed which respond preferentially to visual stimuli presented in spatial congruence with our hands (Graziano, Proc Natl Acad Sci USA 96:10418–10421, 1999). In this study, we examined event-related potentials (ERPs) elicited by laser dots projected onto or above participants’ index and middle fingers during a sustained-attention task. We hypothesized that visual stimuli projected onto the hand would elicit differences in ERP deflections related to sensory gating and categorization in comparison to when projected close to the hand. Participants responded via a footswitch to rare target flashes of light occurring on or directly above the middle finger of the attended hand. We found enhanced amplitudes of the N1 and P3 deflections when the stimuli fell onto the finger tips as opposed to above them. Furthermore, the N1 for unattended stimuli was less suppressed when the lasers were projected onto the fingers. Behaviorally, participants were less accurate to targets when the lasers fell onto the fingers. We conclude that when the lasers appear to “touch” the participants, they act to automatically draw participants’ attention. Thus visual stimuli projected onto the fingers of the ‘unattended’ hand are harder to filter out, leading to decreases in accuracy during task performance.
Atomistic mechanisms of dopant-induced multiple quantum well mixing and related phenomena

We discuss mechanisms of Ga self-diffusion and impurity diffusion in GaAs, and of layer mixing enhancement in GaAs/AlGaAs multiple quantum wells (MQWs). Ga self-diffusion and Ga-Al interdiffusion are governed by the triply negatively charged Ga vacancies, V Ga 3− , under intrinsic and n-doping conditions, and by doubly positively charged Ga self-interstitials, I Ga 2+ , under heavy p-doping conditions. The mechanisms responsible for enhancing MQW mixing are the Fermi-level effect for the n-dopants Si and Te, and the combined effects of the Fermi-level and the dopant diffusion-induced nonequilibrium point defects for the p-dopants Zn and Be. For n-type GaAs the donor Si atoms diffuse primarily also via V Ga 3− . For p-type GaAs the interstitial-substitutional impurities Zn and Be diffuse via the kickout mechanism and induce a supersaturation and an undersaturation in the concentrations of I Ga 2+ , respectively, under indiffusion and outdiffusion conditions.
Raman spectroscopic determination of hydration number of methane hydrates

Hydration numbers of methane hydrates with various water/gas ratios of the sample were measured by Raman spectroscopy. Artificial methane hydrates were formed at temperatures ranging from 273.2 to 278.4 K, and pressures from 3.0 to 7.0 MPa, with a stirring rate of approximately 500 rpm. Under such nonequilibrium conditions, the obtained hydrate samples had a water/gas ratio ranging from 6.4 to 17.4, which was determined by mass measurements. The spectroscopic analysis revealed, however, that the crystallographic hydration number was almost constant at 6.2±0.2, which corresponds to the hydration number estimated from the thermodynamic model. The same measurements were carried out on natural gas hydrate samples obtained from the deep-sea floor of Blake Ridge. The coincidence of the hydration numbers between natural and artificial samples indicated that the crystallographic hydration number is independent of the formation conditions and the large variation in the water/gas ratio of samples is described by the ratio between pure hydrate and free water.
Far infrared transmission through metal light pipes

The fractional transmission of far infrared radiation through metal light pipes is calculated and compared with experimental data. Transmission factors greater than fifty percent are obtained over distances of several feet with typical parameters. Condensing cones allow the output radiation to be concentrated onto a small detector area for spectroscopic applications.
Nucleocytoplasmic Cdk5 is involved in neuronal cell cycle and death in post-mitotic neurons

In a variety of neurodegenerative disease, despite the frequent correlation of neuronal cell cycle and cell death in the same neuronal populations, the mechanistic pathway linking the two remains undefined. One possible link is the atypical cyclin dependent kinase, Cdk5. Cdk5 exerts a double protective function in neurons, first by suppressing the cell cycle in the nucleus and second by suppressing cell death in the cytoplasm. Cdk5 transport between nucleus and cytoplasm serves to regulate the balance between these two events. Cdk5 nuclear localization relies on its interaction with p27, and its cell cycle suppression activity is achieved by direct binding to E2F1, disrupting the DP1-E2F1 dimer and its DNA binding ability. To bind to E2F1, Cdk5 does not need to be catalytically active but it does require a physical association with both p27 and its cyclin-like activator, p35. Because of this requirement, the proper levels and locations of p27 and p35 are characteristics that endow a neuron a unique form o...
Domain mu-calculus

The basic framework of domain μ-calculus was formulated in [39] more than ten years ago. This paper provides an improved formulation of a fragment of the μ-calculus without function space or powerdomain constructions, and studies some open problems related to this μ-calculus such as decidability and expressive power. A class of language equations is introduced for encoding μ-formulas in order to derive results related to decidability and expressive power of non-trivial fragments of the domain μ-calculus. The existence and uniqueness of solutions to this class of language equations constitute an important component of this approach. Our formulation is based on the recent work of Leiss [23], who established a sophisticated framework for solving language equations using Boolean automata (a.k.a. alternating automata [12, 35]) and a generalized notion of language derivatives. Additionally, the early notion of even-linear grammars is adopted here to treat another fragment of the domain μ-calculus.
Consequences of gauge invariance for the interacting vertices in non-abelian gauge theories

Abstract The most general form of the triple-gluon vertex consistent with the requirements of gauge invariance is determined in both axial and covariant gauges.
Voice training and therapy with a semi-occluded vocal tract: rationale and scientific underpinnings.

Purpose Voice therapy with a semi-occluded vocal tract has a long history. The use of lip trills, tongue trills, bilabial fricatives, humming, and phonation into tubes or straws has been hailed by ...
Elevated Fear Conditioning to Socially Relevant Unconditioned Stimuli in Social Anxiety Disorder

Objective: Though conditioned fear has long been acknowledged as an important etiologic mechanism in social anxiety disorder, past psychophysiological experiments have found no differences in general conditionability among social anxiety patients using generally aversive but socially nonspecific unconditioned stimuli (e.g., unpleasant odors and painful pressure). The authors applied a novel fear conditioning paradigm consisting of socially relevant unconditioned stimuli of critical facial expressions and verbal feedback. This study represents the first effort to assess the conditioning correlates of social anxiety disorder within an ecologically enhanced paradigm. Method: Subjects with social anxiety disorder and age- and gender-matched healthy comparison subjects underwent differential classical conditioning. Conditioned stimuli included images of three neutral facial expressions, each of which was paired with one of three audiovisual unconditioned stimuli: negative insults with critical faces (USneg), positive compliments with happy faces (USpos), or neutral comments with neutral faces (USneu). The conditioned response was measured as the fear-potentiation of the startle-blink reflex elicited during presentation of the conditioned stimuli. Results: Only social anxiety subjects demonstrated fear conditioning in response to facial expressions, as the startleblink reflex was potentiated by the CSneg versus both CSneu and CSpos among those with the disorder, while healthy comparison subjects displayed no evidence of conditioned startle-potentiation. Such group differences in conditioning were independent of levels of anxiety to the unconditioned stimulus, implicating associative processes rather than increased unconditioned stimulus reactivity as the active mechanism underlying enhanced conditioned startle-potentiation among social anxiety subjects. Conclusions: Results support a conditioning contribution to social anxiety disorder and underscore the importance of disorder-relevant unconditioned stimuli when studying the conditioning correlates of pathologic anxiety.
Dextran and Polymer Polyethylene Glycol (PEG) Coating Reduce Both 5 and 30 nm Iron Oxide Nanoparticle Cytotoxicity in 2D and 3D Cell Culture

Superparamagnetic iron oxide nanoparticles are widely used in biomedical applications, yet questions remain regarding the effect of nanoparticle size and coating on nanoparticle cytotoxicity. In this study, porcine aortic endothelial cells were exposed to 5 and 30 nm diameter iron oxide nanoparticles coated with either the polysaccharide, dextran, or the polymer polyethylene glycol (PEG). Nanoparticle uptake, cytotoxicity, reactive oxygen species (ROS) formation, and cell morphology changes were measured. Endothelial cells took up nanoparticles of all sizes and coatings in a dose dependent manner, and intracellular nanoparticles remained clustered in cytoplasmic vacuoles. Bare nanoparticles in both sizes induced a more than 6 fold increase in cell death at the highest concentration (0.5 mg/mL) and led to significant cell elongation, whereas cell viability and morphology remained constant with coated nanoparticles. While bare 30 nm nanoparticles induced significant ROS formation, neither 5 nm nanoparticles (bare or coated) nor 30 nm coated nanoparticles changed ROS levels. Furthermore, nanoparticles were more toxic at lower concentrations when cells were cultured within 3D gels. These results indicate that both dextran and PEG coatings reduce nanoparticle cytotoxicity, however different mechanisms may be important for different size nanoparticles.
Mitsunobu mischief: neighbor-directed histidine N(τ)-alkylation provides access to peptides containing selectively functionalized imidazolium heterocycles

There are few methodologies that yield peptides containing His residues with selective N(τ), N(π)-bis-alkylated imidazole rings. We have found that, under certain conditions, on-resin Mitsunobu coupling of alcohols with peptides having a N(π)-alkylated His residue results in selective and high-yield alkylation of the imidazole N(τ) nitrogen. The reaction requires the presence of a proximal phosphoric, carboxylic or sulfonic acid, and proceeds through an apparent intramolecular mechanism involving Mitsunobu intermediates. These transformations have particular application to phosphopeptides, where “charge masking” of one phosphoryl anionic charge by the cationic histidine imidazolium ion is now possible. This chemistry opens selective access to peptides containing differentially functionalized imidazolium heterocycles, which provide access to new classes of peptides and peptide mimetics.
Quantification of biogenic volatile organic compounds with a flame ionization detector using the effective carbon number concept

Abstract. Biogenic volatile organic compounds (BVOCs) are emitted into the atmosphere by plants and include isoprene, monoterpenes, sesquiterpenes, and their oxygenated derivatives. These BVOCs are among the principal factors influencing the oxidative capacity of the atmosphere in forested regions. BVOC emission rates are often measured by collecting samples onto adsorptive cartridges in the field and then transporting these samples to the laboratory for chromatographic analysis. One of the most commonly used detectors in chromatographic analysis is the flame ionization detector (FID). For quantitative analysis with an FID, relative response factors may be estimated using the effective carbon number (ECN) concept. The purpose of this study was to determine the ECN for a variety of terpenoid compounds to enable improved quantification of BVOC measurements. A dynamic dilution system was developed to make quantitative gas standards of VOCs with mixing ratios from 20–55 ppb. For each experiment using this system, one terpene standard was co-injected with an internal reference, n-octane, and analyzed via an automated cryofocusing system interfaced to a gas chromatograph flame ionization detector and mass spectrometer (GC/MS/FID). The ECNs of 16 compounds (14 BVOCs) were evaluated with this approach, with each test compound analyzed at least three times. The difference between the actual carbon number and measured ECN ranged from −24% to −2%. The difference between theoretical ECN and measured ECN ranged from −22% to 9%. Measured ECN values were within 10% of theoretical ECN values for most terpenoid compounds.
Worldwide distribution of group velocity of mantle Rayleigh waves as determined by spherical harmonic inversion

We have determined the worldwide distribution of group velocity of mantle Rayleigh waves for periods between 100 and 300 sec without assuming any regionalization. Group slowness 1/u(θ, φ) is expressed by spherical harmonics, and the coefficients, up to angular order 7, have been determined from travel times of Rayleigh waves by a least-squares method. From these, u(θ, φ) has been synthesized. Since we cannot obtain information about the odd terms of the expansion from one circuit measurements around the world, we have used group velocities of mainly R_2 and R_3. The overall pattern of u(θ, φ) for periods between 100 and 200 sec is consistent with results of previous pure-path and regional studies. Group velocities for tectonically active regions are low, and those of the shields and the northwestern Pacific are high.
Capacitor voltage balancing using minimum loss SVPWM for a five-level diode-clamped converter

DC capacitor voltage imbalance is an inevitable technical concern for the multilevel diode-clamped converters with number of levels higher than two. This paper addresses the balancing of the capacitor voltages based on the capacitor current equalization considering a minimum loss space vector pulse width modulation (MLSVPWM) algorithm for five-level diode-clamped converters. In diode-clamped converter topology, individual capacitors are connected in series on the DC side of the converter. By choosing appropriate switching pattern and their duration in a combined manner, the current passing through each capacitor can be controlled very competently. Using the redundant switching patterns for the proposed control strategy, number of switching that is required for the operation can also be minimized in addition to capacitor voltage balancing, without the requirement of complex calculations. The proposed MLSVPWM modulation technique for voltage balancing is verified using circuit simulations.
A two-dimensional equity proposal for self-sufficiency in municipal safety-net hospitals.

This article advances a two-dimensional equity approach for self-sufficiency in municipal safety-net hospitals that will strengthen provider self-sufficiency and protect the safety-net mission of providing a dignified floor of health services to the most disadvantaged members of the society. The model responds to the failure of current delivery strategies to effectively cope with the changing market configurations in safety-net systems that have eliminated the possibility of cross-subsidization which has long been the mainstay of safety-net systems. The identified pathway to self sufficiency is made up of (1) a differential service delivery framework which includes a two-tier patient system, uniform standards of care and service levels, and the creation of a community health campus; (2) independent sector ownership; and (3) intergovernmental policy actions restricting ownership of safety-net hospitals to nonprofit entities. Although this model is explained by demonstrating potential application in safety-...
THE AUTISTIC CHILD LEARNS TO READ

*The author is indebted to Irene Kassorla and Roslyn Stewart, who served as teachers and research assistants in the programmes for Kate and Patrick
Modeling the relationship among brownfields, property values, and community revitalization

The main focus in redeveloping brownfields is on the most marketable properties, typically found in the healthiest urban neighborhoods. As evidenced by the rapid redevelopment that many communities are experiencing, this approach is helping to return brownfields to productive use. Yet not all brownfields are being cleaned up, nor are there enough resources to do so soon. Thus, from the perspective of community revitalization and of economic justice, we need to ask whether it matters which properties in which neighborhoods are receiving these scarce funds. That is, does the existence of brownfields in a neighborhood affect residential property values and capacity for revitalization? To answer these questions, we use hedonic modeling to determine the impact of brownfields on property values in Atlanta and Cleveland. Our results suggest that short-term economic efficiency is neither the most appropriate nor the only criterion on which to base public investment decisions for remediation.
Rod-like bacterial shape is maintained by feedback between cell curvature and cytoskeletal localization

Cells typically maintain characteristic shapes, but the mechanisms of self-organization for robust morphological maintenance remain unclear in most systems. Precise regulation of rod-like shape in Escherichia coli cells requires the MreB actin-like cytoskeleton, but the mechanism by which MreB maintains rod-like shape is unknown. Here, we use time-lapse and 3D imaging coupled with computational analysis to map the growth, geometry, and cytoskeletal organization of single bacterial cells at subcellular resolution. Our results demonstrate that feedback between cell geometry and MreB localization maintains rod-like cell shape by targeting cell wall growth to regions of negative cell wall curvature. Pulse-chase labeling indicates that growth is heterogeneous and correlates spatially and temporally with MreB localization, whereas MreB inhibition results in more homogeneous growth, including growth in polar regions previously thought to be inert. Biophysical simulations establish that curvature feedback on the localization of cell wall growth is an effective mechanism for cell straightening and suggest that surface deformations caused by cell wall insertion could direct circumferential motion of MreB. Our work shows that MreB orchestrates persistent, heterogeneous growth at the subcellular scale, enabling robust, uniform growth at the cellular scale without requiring global organization.
LAPAROSCOPIC ORCHIOPEXY: PROCEDURE OF CHOICE FOR THE NONPALPABLE TESTIS?

AbstractPurpose: Multiple approaches exist for the management of the nonpalpable testis. With the use of diagnostic laparoscopy widely accepted in the setting of the nonpalpable testis we have found laparoscopic orchiopexy to be an efficient and logical extension. To evaluate its use we report our experience with laparoscopic orchiopexy to treat 44 nonpalpable testes in 36 patients.Materials and Methods: We retrospectively reviewed the medical records of all patients who underwent laparoscopic orchiopexy for a 2 1/2-year period. Modifications of the surgical technique are described.Results: The left testis was affected in 18 boys, the right in 9 and both in 9. At laparoscopy 8 testes were at the internal ring or were peeping and the remainder were intra-abdominal. One patient underwent a unilateral 1-stage Fowler-Stephens orchiopexy, and 3 unilateral and 1 bilateral 2-stage Fowler-Stephens orchiopexy. Two patients underwent laparoscopically assisted orchiectomy. The remaining 31 patients underwent laparos...
Transmission electron microscopy studies of the nanoscale structure and chemistry of Pt50Ru50 electrocatalysts.

The structural and chemical heterogeneity of 2.5-nm Pt50Ru50 electrocatalysts was studied by transmission electron microscopy using selected area diffraction, lattice imaging, electron-energy loss spectroscopy, and energy-dispersive X-ray spectroscopy. The catalysts with the highest methanol oxidation activities exhibit oxidation-induced phase separation on the nanoscale to form Pt-rich metal embedded in Ru-rich hydrous and anhydrous oxide. Reduction of the oxide-on-metal samples produces a true bimetallic face-centered cubic Pt50Ru50 alloy, with 275 times lower oxidation activity.
An Objective Assessment Tool for Basic Surgical Knot-Tying Skills

Objective To determine if a knot-tying checklist can provide a valid score and if the checklist can be used by novice surgeons in a reliable manner. Methods This study was conducted at the Surgical Skills Center at the University of California, San Francisco. A knot-tying checklist was developed from a kinesthetic knot-tying curriculum. Novice (67 first-year medical students) and experienced surgeons (8 residents postgraduate year 3 and higher and 2 attending physicians) were videotaped performing 4 knot-tying tasks, and the videotapes were rated with a global score and a checklist by interns ( n = 3) and experienced ( n = 3) surgeons. Results Both interns and experienced surgeons can use the knot-tying checklist with acceptable reliabilities (>0.8 with 3 raters). The checklist is able to differentiate between novice and experienced surgeons, when used by both interns and experienced raters. The expert knot-tying score correlated with the global score overall ( r = 0.88) and for each task ( r was 0.82 for task 1, 0.85 for task 2, 0.80 for task 3, and 0.81 for task 4). Conclusions The knot-tying checklist provides a valid score for basic surgical knot-tying and can be used by novice and experienced raters. Its use supports peer assessment of performance in a surgical skills laboratory setting.
The Bowen ratio-energy balance method for estimating latent heat flux of irrigated alfalfa evaluated in a semi-arid, advective environment

The Bowen ratio-energy balance (BREB) is a micrometeorological method often used to estimate latent heat flux because of its simplicity, robustness, and cost. Estimates of latent heat flux have compared favorably with other methods in several studies, but other studies have been less certain, especially when there was sensible heat advection. We compared the latent heat flux of irrigated alfalfa (Medicago sativa, L.) estimated by the BREB method with that measured by lysimeters over a growing season in the semi-arid, advective environment of the southern High Plains. Difference statistics from the comparison and indicators of sensible heat advection were used to analyze the performance of the BREB method relative to lysimeters. Latent heat flux was calculated from mass change measured by two precision weighing lysimeters and from two BREB systems that used interchanging temperature and humidity sensors. Net radiation (Rn), soil heat flux ( G), and other meteorological variables were also measured. Difference statistics included the root mean square difference (RMSD) and relative RMSD (normalized by mean lysimeter latent heat flux). Differences between lysimeters averaged 5‐15% during the day, and 25‐45% at night. Estimates of latent heat flux by the two BREB systems agreed closely (relative RMSD D8%) when they were at the same location with sensors at the same height. Differences increased when the location was the same but sensors were at different heights, or when the sensor height was the same but location in the field different, and probably was related to limited fetch and the influence of different source areas beyond the field. Relative RMSD between lysimeter and BREB latent heat fluxes averaged by cutting was 25‐29% during the first two cuttings and decreased to 16‐19% during the last three cuttings. Relative RMSD between the methods varied from 17 to 28% during morning hours with no pattern based on cutting. Afternoon relative RMSD was 25% during the first two cuttings and decreased to 15% during subsequent cuttings. Greatest differences between the two methods were measured when the Bowen ratios were less than 0, on days that were hot, dry and windy, or when the latent heat flux exceeded the available energy ( Rn G). These conditions were likely to be encountered throughout the growing season, but were more common earlier in the season. © 2000 Elsevier Science B.V. All rights reserved.
Framework stabilization of Si-rich LTA zeolite prepared in organic-free media

Zeolite HOU-2 (LTA type) is prepared with the highest silica content (Si/Al = 2.1) reported for Na-LTA zeolites without the use of an organic structure-directing agent. The rational design of Si-rich zeolites has the potential to improve their thermal stability for applications in catalysis, gas storage, and selective separations.
A New Indexing Method for Approximate Search in Text Databases

We present an index structure to support the approximate keyword search in text databases. In an approximate keyword search query, the user presents a query word Q and a tolerance value k (kges0), and wishes to find all documents in the database that contain the query word Q or any other word in the vocabulary that matches Q approximately (We say that two words match each other approximately if the edit distance between them does not exceed the tolerance value k. In a typical text database application, a user chooses k=1, 2, 3, or 4). Our index structure is built on the underlying vocabulary of the text database. The new technique has two principal components - a new data structure called the V-tree and its partition methods for clustering words in the vocabulary into subgroups. We have implemented our index structure and conducted experiments on real-world data. Our experiments show that even for very large text database, the construction of our index and a search for keywords that match the query word approximately can be done quickly. Our implementation makes it clear that the V-tree data structure can be easily integrated into existing access structures built on the database such as the inverted index file
Determination of optimal sizes for a first and second level SRAM-DRAM on-chip cache combination

In this paper, an SRAM-DRAM combination memory is used as an on-chip cache memory. The SRAM portion is considered to be the first level cache and the DRAM portion is considered to be the second level cache. Curves are derived for the optimal SRAM and DRAM sizes with memory access time optimized. These curves do vary with the amount of fixed on-chip area available, with different cell size ratios of DRAM to SRAM and with varying DRAM access times. The optimal amount of SRAM, or first level cache, is consistently seen to be much smaller then the general trend toward a large first level cache. For instance, if the on-chip area available for cache could contain 256 K of SRAM then only about 16 K of SRAM should exist along with 2.5 M of DRAM as second level cache for optimal usage of that area. >
Metal-Catalyzed Oxidation of Brain-Derived Neurotrophic Factor (BDNF): Analytical Challenges for the Identification of Modified Sites

Purpose. We examined the metal-catalyzed oxidation of brain-derivedneurotrophic factor (BDNF) using the Cu(II)/ascorbate/O2 modeloxidative system.
Homeostatic potassium excretion in fed and fasted sheep

In unanesthetized adult sheep, following intake of a daily meal, there was a peak in K excretion. The maximum and minimum rates of K excretion following meals were directly related to meal K content. On days without meals, no peak in K excretion occurred. Changes in K excretion on fed and fast days occurred without changes in the low levels of plasma aldosterone and were poorly correlated with urine or blood pH, urine flow rate, Na excretion, or the filtered load of K, but they correlated well with fractional K excretion. Plasma K did not change on fast days. Plasma K increased on some, but not all, fed days. Increases in plasma K that occurred on fed days were insufficient to account for the concurrent kaliuresis. Infusion of aldosterone or isotonic NaCl failed to alter K excretion in fed or fasted sheep. Infusion of isotonic NaCl + aldosterone hypertonic Na2SO4 + aldosterone increased K excretion in fasted but not fed sheep. Infusion of K in the rumen of fed and fasted sheep elevated rumen K concentration and led to increases in K excretion that could not be explained by increases in plasma K. The mechanisms responsible for the homeostatic changes in K excretion on fed and fast days were not ascertained but may importantly depend on sensors of enteric K content.
School Start Times, Sleep, Behavioral, Health, and Academic Outcomes: A Review of the Literature.

BACKGROUND Insufficient sleep in adolescents has been shown to be associated with a wide variety of adverse outcomes, from poor mental and physical health to behavioral problems and lower academic grades. However, most high school students do not get sufficient sleep. Delaying school start times for adolescents has been proposed as a policy change to address insufficient sleep in this population and potentially to improve students' academic performance, reduce engagement in risk behaviors, and improve health. METHODS This article reviews 38 reports examining the association between school start times, sleep, and other outcomes among adolescent students. RESULTS Most studies reviewed provide evidence that delaying school start time increases weeknight sleep duration among adolescents, primarily by delaying rise times. Most of the studies saw a significant increase in sleep duration even with relatively small delays in start times of half an hour or so. Later start times also generally correspond to improved attendance, less tardiness, less falling asleep in class, better grades, and fewer motor vehicle crashes. CONCLUSIONS Although additional research is necessary, research results that are already available should be disseminated to stakeholders to enable the development of evidence-based school policies.