cssi/SciSciGPT-SciSciNet huggingface dataset:
Vertical Mixing by Langmuir Circulations

Abstract Wind and surface wave frequently induce Langmuir circulations (LC) in the upper ocean, and the LC contribute to mixing materials down from the surface. In this paper we analyze large-eddy simulation (LES) cases based on surface-wave-averaged, dynamical equations and show that the effect of the LC is a great increase in the vertical mixing efficiency for both material properties and momentum. We provide new confirmation that the previously proposed K-profile parameterization (KPP) model accurately characterizes the turbulent transport in a weakly convective, wind-driven boundary layer with stable interior stratification. We also propose a modest generalization of KPP for the regime of weakly convective Langmuir turbulence. This makes the KPP turbulent flux profiles match those in the LES case with LC present fairly well, especially so for material properties being transported downwards from the ocean surface. However, some open issues remain about how well the present LES and KPP formulations represent Langmuir turbulence, in part because wave-breaking effects are not yet included.
An observational study of frequency of provider hand contacts in child care facilities in North Carolina and South Carolina.

Background Children enrolled in child care are 2.3-3.5 times more likely to experience acute gastrointestinal illness than children cared for in their own homes. The purpose of this study was to determine the frequency surfaces were touched by child care providers to identify surfaces that should be cleaned and sanitized. Methods Observation data from a convenience sample of 37 child care facilities in North Carolina and South Carolina were analyzed. Trained data collectors used iPods (Apple, Cupertino, CA) to record hand touch events of 1 child care provider for 45 minutes in up to 2 classrooms in each facility. Results Across the 37 facilities, 10,134 hand contacts were observed in 51 classrooms. Most (4,536) were contacts with porous surfaces, with an average of 88.9 events per classroom observation. The most frequently touched porous surface was children's clothing. The most frequently touched nonporous surface was food contact surfaces (18.6 contacts/observation). Surfaces commonly identified as high-touch surfaces (ie, light switches, handrails, doorknobs) were touched the least. Conclusion General cleaning and sanitizing guidelines should include detailed procedures for cleaning and sanitizing high-touch surfaces (ie, clothes, furniture, soft toys). Guidelines are available for nonporous surfaces but not for porous surfaces (eg, clothing, carpeting). Additional research is needed to inform the development of evidence-based practices to effectively treat porous surfaces.
Evaluation of the Clinical Application of the ACCF/ASE Appropriateness Criteria for Stress Echocardiography

Background The aim of this study was to evaluate the clinical application of the American College of Cardiology Foundation and American Society of Echocardiography appropriateness criteria for stress echocardiography (SE) in a single-center university hospital. Methods Indications were determined for consecutive studies by two reviewers and categorized as appropriate, uncertain, or inappropriate. Results Of 477 studies for which primary indications could be determined, 188 specifically related to university transplantation programs were excluded. Of the remaining 289 studies, 88% were addressed in the appropriateness criteria for SE. Of these, 71% were appropriate, 9% were uncertain, and 20% were inappropriate. Inappropriate studies were more likely to be ordered on younger patients and women and were less likely to be ordered by cardiologists. Abnormal results on SE were more frequent among appropriate than inappropriate studies. Conclusions The appropriateness criteria for SE encompass and effectively characterize the majority of studies ordered in a single-center university hospital and appear to reasonably stratify the likelihood of abnormal results on SE. However, revisions will be required to fully capture and stratify appropriate clinical practice of SE.
Polyunsaturated fatty acids of mosquitos reared with single dietary polyunsaturates

Abstract Stock adults of Culex pipiens and tarsalis reared in crude media had a third of their phospholipid fatty acids as polyunsaturates, mainly 18C but including prominent proportions of arachidonic (20:4n6) and eicosapentaenoic (20:5n3) acids. Adults reared with synthetic media devoid of polyunsaturated fatty acids and therefore unable to fly at emergence contained no more than trace amounts of any polyunsaturate. With synthetic media containing single polyunsaturates the following findings emerged. Of four polyunsaturates known to be highly effective essential fatty acids individually 20:4n6 or 20:5n3 appeared unchanged in tissue phospholipids in proportions reflecting dietary concentrations; dietary 22:4n6 or 22:6n3 (docosahexaenoic acid) appeared also as 20:4n6 or 20:5n3, respectively, retroconverted from the administered dietary fatty acids, which were detected only in traces. Two moderately effective dietary fatty acids, 18:3n6 (γ-linolenic) and 20:3n6 (homo-γ-linolenic), which support weak flight at emergence, appeared in tissue phospholipids respectively as 18:3n6 only, or as similar proportions of 18:3n6 and 20:3n6, this latter indicating shortening to the 18C analogue as well as accumulation of the dietary 20C acid. Six other polyunsaturates [18:2n6 (linoleic), 18:3n3 (linolenic) and their 20C and 22C analogues], all considered slightly effective as essential fatty acids although unable to support proper flight, appeared in tissue phospholipid in dose-related proportions as the 18C basal n6 or n3 family analogues, with only traces of the higher analogues when these were the dietary fatty acids provided, indicating sequential chain shortening within each series, n6 or n3, no interconversion of n6 and n3 members (also shown by all other data), and efficient accumulation of the resultant 18C polyunsaturates. These findings show no capability for de novo synthesis of polyunsaturated fatty acids, afford an insight into the metabolic interrelations of diet-derived polyunsaturates and indicate a primary importance for endogenous arachidonic and eicosapentaenoic acids in mosquito essential fatty acid physiology.
Is sexual maturity occurring earlier among U.S. children

Abstract Purpose To compare the onset and completion of sexual maturation among U.S. children between 1966 and 1994. Methods Tanner stages were from 3042 non-Hispanic white boys, 478 black boys, 2625 white girls, and 505 black girls (NHES 1966–70), from 717 Mexican-American boys and 712 Mexican-American girls (HHANES 1982–84) and from 259 non-Hispanic white boys, 411 black boys, 291 white girls, 415 black girls, 576 Mexican-American boys and 512 Mexican-American girls (NHANES III 1988–1994). Proportions of entry into a stage, probit analysis estimated medians and selected percentiles for ages at entry were calculated using SUDAAN. Results NHANES III (1988–1994) non-Hispanic white boys entered stage 2, 3, and 4 genital development and stages 3 and 4 pubic hair earlier than NHES (1966–1970) white boys, but they entered stage 5 genital development significantly later. NHANES III (1988–1994) Mexican-American boys were in stage 2, 3 and 4 genital development earlier than HHANES (1982–1984) boys, but entry into stage 5 genital and pubic hair development was not significant. NHANES III (1988–1994) white girls entered stage 5 pubic hair later than NHES (1966–1970) white girls. NHANES III (1988–1994) Mexican-American girls entered stage 2 breast and pubic hair development earlier than HHANES (1982–1984) girls, entered stage 4 breast and pubic hair development earlier but entered stage 5 pubic hair later than the HHANES (1982–1984) girls. Conclusion Persuasive evidence of a secular trend toward early maturation is not found between 1966 and 1994 in non-Hispanic black boys and non-Hispanic black and white girls. Some evidence of this trend is found in non-Hispanic white boys between 1966 and 1994 and in Mexican-American boys and girls between 1982 and 1994.
Transplantation of ABO A2 kidneys into O recipients: do IgM anti‐A1 titers matter?

Background The ABO blood subgroup A2 expresses lower levels of A antigen on the cell surface and is less immunogenic toward anti-A immunoglobulin present in blood type O or B recipients. Previous studies have shown successful kidney transplantation from A2 donors into O or B recipients with low pre-transplant anti-A titers. Previous studies suggest good results with recipient IgG titers <1:8. Few studies have specifically evaluated the importance of anti-A1 IgM titers on early outcomes following A2 to O or B kidney transplantation. Methods We performed a single center, retrospective review of all A2 to O living donor kidney transplants. All recipients had pre-transplant anti-A IgG titers <1:8. IgM titers were measured in all recipients and were reported but not used to determine eligibility for transplant. Results From 2001 to 2013, we performed seven consecutive A2 to O living donor kidney transplants. Early allograft dysfunction, acute rejection or thrombotic microangiopathy, occurred in four patients and were associated with high IgM titers despite low IgG titers. Conclusions Our data show a high incidence of early acute rejection or thrombotic microangiopathy in A2 to O kidney transplants with high recipient anti-A IgM titers despite low IgG titers. Steps to lower anti-IgM pre-transplant may reduce the risk of early allograft dysfunction in A2 to O or B kidney transplants. Attention should be paid to IgM titers in establishing individual center selection criteria for A2 to B kidney transplants under the new UNOS kidney allocation system.
Compressibility effects in modeling complex turbulent flows

Abstract The effect of compressibility on the structure of turbulence is an important, but difficult, topic in turbulence modeling. Modeling issues in production, dissipation and transport of turbulent kinetic energy need to be addressed to account for Mach number effects. In the present review, the compressibility effect is investigated in the context of engineering models needed for complex flow computations, particularly the k−e model. Issues such as the dissipative nature of compressibility, the complexities arising due to the non-divergent nature of the velocity field, added time-scale effect due to a non-equilibrium between the rates of production and dissipation of turbulent kinetic energy, the enthalpic production term and the term representing the baroclinic effect, have been discussed to facilitate the inclusion of these terms in the solution of compressible turbulent flow fields. Flows characterized by strong streamline curvature and inhomogeneities arising due to strong shocks and rapid expansions, in the form of supersonic flow past an axi-symmetric afterbody and hypersonic flow past a projectile, have been adopted to facilitate computational assessment of these aspects.
Lower Bounds for the Resonant Frequencies of Nonuniform Frame Structures

The theory and practice of computing rigorous lower bounds to eigenvalues through the methodology of intermediate problems is extended to general frame structures with nonprismatic beam elements. Intermediate operator constructions for each substructure are used to ensure bounding of the actual resonances from below. The assembly of the elemental intermediate problems into a global dynamic stiffness matrix is discussed together with computational results that illustrate the method applied to a simple planar frame. Die Theorie und Praxis der Berechnung strenger unterer Schranken fur Eigenwerte durch die Methode der Zwischenprobleme wird auf allgemeine Stabwerke mit nichtprismatischen Balkenelementen ausgedehnt. Fur jede Unterstruktur werden Zwischenoperator-Konstruktionen verwendet, um eine Einschrankung der aktuellen Resonanzen von unten her zu sichern. Die Einordnung der Elementar-Zwischenprobleme in eine globale dynamische Steifigkeitsmatrix wird zusammen mit den rechnerischen Ergebnissen diskutiert, die die Methode, angewandt auf ein einfaches ebenes Stabwerk illustriert.
Effects of Ocular Carteolol and Timolol on Plasma High-density Lipoprotein Cholesterol Level

Fifty-eight healthy, normolipidemic adult men participated in a prospective, masked, randomized crossover study designed to compare the effects of two topical nonselective β-adrenergic antagonists, Carteolol and timolol, on plasma high-density lipoprotein cholesterol levels. Two eight-week treatment periods were separated by an eight-week drug-free period. Carteolol 1.0% or timolol 0.5% was used, one drop twice daily, in both eyes without nasolacrimal occlusion. Fresh plasma was assayed for levels of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, and apolipoproteins A-I and B-100. With indistinguishable effects on intraocular pressure, Carteolol and timolol induced different (P = .013) decrements in high-density lipoprotein cholesterol levels. Carteolol treatment decreased high-density lipoprotein cholesterol levels by 3.3% (-0.04 mmol/l) and raised the ratio of total to high-density lipoprotein cholesterol levels by 4.0% (0.15 unit); timolol treatment decreased high-density lipoprotein cholesterol levels by 8.0% (-0.10 mmol/l) and raised the ratio of total to high-density lipoprotein cholesterol levels by 10.0% (0.37 unit). There was no differential drug effect on the other lipid variables measured. Ocular nonselective β-adrenergic antagonist therapy can produce clinically relevant decrements in high-density lipoprotein cholesterol levels in healthy men.
The synthesis of cadmium doped mesoporous TiO2

Abstract Cd doped mesoporous titanium oxide was prepared using non-ionic surfactants and easily handled titanium precursors. The Cd doping was found to be able to significantly inhibit the growth of anatase crystal size, stabilize the mesoporous structure, and retard the densification of nanoporous TiO2 at elevated temperatures.
Has the Native Population of New England Been Dying Out

Introduction, 2. — Previous discussions, 2. — Fertility rates, 7. — Lack of adequate data makes it impossible to reach precise conclusions of New England dying out, 9. — But such data as are available support the contention that the natives of New England are not maintaining their numbers, 14. — Conclusions, 18.
Cell design to separate nonferrous metals in incinerator residue with magnetic fluids

Abstract A magnetogravimetric separation method has been devised to fractionate a mixture of nonferrous metals recovered from municipal incinerator residues. By properly placing a colloidal solution of magnetite in kerosene between the poles of a magnet, it was possible to separate particles according to their density spectrum in a continuous fashion. A simple experiment was devised to determine the horizontal displacement exerted on an object by a nonvertical magnetic levitation force and to assist in the design of larger separators. Angular deflection and horizontal displacement of objects having specific gravity ranging from 1.15 to 11.34 in a magnetic fluid with a saturation magnetization of 170 gauss were determined. A multicomponent separator with three channels served to fractionate nonferrous metals into three splits according to density. The bulk of magnetic fluid adhering to the separated particles was recovered by floating on water and skimming off with the aid of moving magnets.
The cocktail party effect in infants

Most speech research with infants occurs in quiet laboratory rooms with no outside distractions. However, in the real world, speech directed to infants often occurs in the presence of other competing acoustic signals. To learn language, infants need to attend to their caregiver’s speech even under less than ideal listening conditions. We examined 7.5-month-old infants’ abilities to selectively attend to a female talker’s voice when a male voice was talking simultaneously. In three experiments, infants heard a target voice repeating isolated words while a distractor voice spoke fluently at one of three different intensities. Subsequently, infants heard passages produced by the target voice containing either the familiar words or novel words. Infants listened longer to the familiar words when the target voice was 10 dB or 5 dB more intense than the distractor, but not when the two voices were equally intense. In a fourth experiment, the assignment of words and passages to the familiarization and testing phases was reversed so that the passages and distractors were presented simultaneously during familiarization, and the infants were tested on the familiar and unfamiliar isolated words. During familiarization, the passages were 10 dB more intense than the distractors. The results suggest that this may be at the limits of what infants at this age can do in separating two different streams of speech. In conclusion, infants have some capacity to extract information from speech even in the face of a competing acoustic voice.
Peroxisomal and Mitochondrial Oxidation of Fatty Acids in the Heart, Assessed from the 13C Labeling of Malonyl-CoA and the Acetyl Moiety of Citrate

We previously showed that a fraction of the acetyls used to synthesize malonyl-CoA in rat heart derives from partial peroxisomal oxidation of very long and long-chain fatty acids. The 13C labeling ratio (malonyl-CoA)/(acetyl moiety of citrate) was >1.0 with 13C-fatty acids, which yields [13C]acetyl-CoA in both mitochondria and peroxisomes and 1 indicates the partial peroxisomal oxidation of oleate and octanoate. In contrast, with [3-13C]octanoate, [1-13C]hexanoate, [1-13C]butyrate, or [1,2-13C2]acetate, the labeling ratio was
Reactions of Lanthanides and Actinides in Molten Alkali Metal/Polychalcogenide Fluxes at Intermediate Temperatures (250-600 °C)

From the reaction of the elemental lanthanides and actinides in molten alkali metal/polychalcogenide salts, several new ternary compounds have been discovered. Specifically, these phases are K4USe8...
Beyond deference and demystification in the sociology of science and technology: A reply to Otero

A response to Otero's criticism of the thesis of the nonrevolutionary character of biotechnology is developed within a larger consideration of the relatively small amount of attention high technologies have received within the sociology of science. It is argued that the “new sociology of science” of the past decade has been a major advance on midcentury functionalist perspectives that took an essentialist, deferential view toward science. The new sociology of science, based on the demystification of science through a relativist view of scientific knowledge production, is nonetheless limited in several respects in its applicability to contemporary issues relating to high technologies. Otero's criticisms are considered in the light of the continuing need for uniting the sociology of science and sociology of technology, and for developing a perspective on science and technology that avoids both uncritical deference and excessive relativization of these forces for social change.
Ras is a mediator of TGFβ1 signaling in developing chick ciliary ganglion neurons

Abstract Large-conductance Ca2+-activated K+ channels (KCa) in chick ciliary ganglion neurons are regulated by target-derived TGFβ1. Here we show that TGFβ1 stimulation of KCa expression was blocked by the structurally dissimilar Ras protein farnesyl transferase inhibitors manumycin-A and FTI-277. A similar effect was produced in ciliary neurons overexpressing RasN17, a widely used dominant-negative form of Ras. Moreover, TGFβ1-evoked increases in phosphorylation of SMAD2 were reduced by manumycin-A, suggesting that Ras-dependent transduction cascades activated by TGFβ1 feed back onto SMAD signaling. Thus, Ras is a mediator of pleiotropic TGFβ1 signaling in developing neurons.
Device for the control and measurement of brush forces to an accuracy of a few grams-force while monitoring brush resistance and brush wear at currents up to 500 A or more

Abstract A brush holder is described which permits the electrical performance of a brush to be tested under currents of up to at least 500 A and speeds of up to at least 70 m s −1 and under brush forces that can be applied and maintained within close limits. Simultaneously, the brush wear can be monitored continuously.
Few channel models of nuclear reactions: Proton and deuteron elastic scattering expansions.

In this paper, an asymmetric, antisymmetrized optical potential formalism is used to derive the low-order terms in multiple-scattering-type expansions for nonrelativistic proton-nucleus and deuteron-nucleus elastic scattering. In particular, the extended Faddeev theory of N-particle collisions is used to obtain the properly symmetrized, two-particle and three-particle contributions in these two cases, where it has been assumed that all potentials are pair interactions. The main purpose underlying the research reported herein has been to prove that standard results can be obtained from an asymmetric formalism. For the two-particle contributions, the usual ${t}^{A}$\ensuremath{\rho}-type expression is obtained, where ${t}^{A}$ is an antisymmetrized, two-particle transition operator. At this level of approximation, the results for the (d,d) case are the same as for the usual folding model. The three-particle contributions in the nucleon-nucleus case are identical to those of Picklesimer and Thaler, thus further demonstrating that standard results are contained in the asymmetric approach. The antisymmetrized, three-particle contributions to the (d,d) optical potential do not seem to have been previously derived; they are the obvious analog of the nucleon-nucleus results, and are physically reasonable in form. However, at this level of approximation, the (d,d) description is no longer found to be that of a folding model.
Human Rights Reference Sources: A Critical Annotated Bibliography

The area of human rights has had significant attention both nationally and internationally in the press and in the political arena. While there is a renewed commitment to human rights advocacy, there is also an upward trend in popular culture of depictions of torture. This article provides critical annotations of English-language reference sources published since 1990 and available both in print and online, in an effort to aid librarians collecting and weeding materials for human rights research.
Aerosol Dynamics in Atmospheric Aromatic Photooxidation

Aerosol formation and growth in aromatic hydrocarbon / NO_x systems was studied in a series of outdoor smog chamber experiments. Analysis of the aerosol size distributions in those experiments that exhibited steady condensational growth provides estimates for the gas-phase partial pressures of the condensing species. Saturation ratios during these growth periods are estimated by comparing these partial pressures with vapor pressures obtained from an analysis of nucleation (Stern et al., 1987), and are found to be in the range of 5 to 20. Modeling of the size–distribution dynamics during the experiments is carried out using the sectional model ESMAP (Warren and Seinfeld, 1985). The full size-distribution model predicts more nucleation than an integral model (Stern et al., 1987), because the polydisperse aerosol representation leads to a lower condensation rate than that predicted for a monodisperse aerosol.
Image patterned molecular delivery into live cells using gold particle coated substrates

An image-patterned molecular delivery system for mammalian cells is demonstrated by pulsed laser irradiation of gold particles immobilized on a substrate below a cell monolayer. Patterned cavitation bubble nucleation was captured using a time-resolved imaging system and molecular delivery verified by observing the uptake of a membrane-impermeable fluorescent dye, calcein. Delivery efficiency as high as 90% was observed and multiplexed, patterned dye delivery was demonstrated.
Complex partial status epilepticus: A depth‐electrode study

Of 87 patients with complex partial epilepsy who were evaluated with depth electrodes, 8 developed complex partial status epilepticus (CPSE). Seizures originated extratemporally in all 8 patients. Frontal lobe onset was established in 4 patients and was probable in 1 more. Medial parietal onset was documented in 1 patient. Medial occipitoparietal onset occurred in another, and 1 patient had multifocal onsets. Even when seizures did not begin frontrally, the frontal lobes were prominently involved during CPSE. CPSE did not occur in 60 patients with seizures originating in the temporal lobe. Both recurrent clinical seizures and continuous altered behavior were observed. Some patients exhibited both clinical patterns at different times during the same episode. Depth recording consistently demonstrated recurrent isolated seizure discharges throughout episodes. The clinical patterns were related, in part, to electroencephalographic seizure frequency, duration, and intensity. Episodes of CPSE were not associated with intellectual deterioration.
Stomach and Duodenum

The stomach is a J-shaped dilation of the alimentary tract derived from the embryonic foregut. It lies in the left upper quadrant of the abdomen where the gastroesophageal junction is located to the left of the 10th thoracic vertebrae and crosses the midline at the pylorus, which is to the right of the LI vertebral body. It is contiguous proximally with the esophagus and distally with the duodenum (Fig. 45.1). The stomach is fixed in two locations, the gastroesophageal junction and the retroperitoneal attachments at the duodenum. It can be divided into four anatomic regions (Fig. 45.2). The cardia is the most proximal region and is located just distal and to the left of the gastroesophageal junction. The fundus projects upward and is in contact with the left hemidiaphragm to the right of the spleen. The corpus, or body, is the largest portion of the stomach and is located below the fundus. The most distal portion of the stomach is the antrum. Its proximal boundary is an arbitrary line connecting the incisura angularis, which is located approximately two-thirds of the distance down the lesser curvature, to the greater curvature where the gastroepiploic arteries enter the stomach.
Closed-form, localized wave solutions in optical-fiber waveguides : comment

The new bidirectional decomposition of the solution to the scalar wave equation introduced by Vengsarkar et al. [ J. Opt. Soc. Am. A9, 937 ( 1992)] characterizing highly directional pulses is shown to have another solution. If the modulation spectra of the pulses considered satisfy a certain conjugation property, this solution turns out to be the complex conjugate of the solution presented in the above reference.
A Comparison of Standard Coherence Models for Inflow Turbulence With Estimates from Field Measurements

The Long-term Inflow and Structural Test (LIST) program, managed by Sandia National Laboratories, Albuquerque, NM, is gathering inflow and structural response data on a modified version of the Micon 65/13 wind turbine at a site near Bushland, Texas. With the objective of establishing correlations between structural response and inflow, previous studies have employed regression and other dependency analyses to attempt to relate loads to various inflow parameters. With these inflow parameters that may be thought of as single-point-in-space statistics that ignore the spatial nature of the inflow, no significant correlation was identified between load levels and any single inflow parameter or even any set of such parameters, beyond the mean and standard deviation of the hubheight horizontal wind speed. Accordingly, hence, we examine spatial statistics in the measured inflow of the LIST turbine by estimating the coherence for the three turbulence components (along-wind, across-wind, and vertical). We examine coherence spectra for both lateral and vertical separations and use the available ten-minute time series of the three components at several locations. The data obtained from spatial arrays on three main rowers located upwind from the test turbine as well as on two additional towers on either side of the main towers consist of 291 ten-minute records. Details regarding estimation of the coherence functions from limited data are discussed. Comparisons with standard coherence models available in the literature and provided in the International Electrotechnical Commission (IEC) guidelines are also discussed. It is found that the Davenport exponential coherence model may not be appropriate especially for modeling the coherence of the vertical turbulence component since it fails to account for reductions in coherence at low frequencies and over large separations. Results also show that the Mann uniform shear turbulence model predicts coherence spectra for all turbulence components and for different lateral separations better than the isotropic von Karman model. Finally, on studying the cross-coherence among pairs of turbulence components based on field data, it is found that the coherence observed between along-wind and vertical turbulence components is not predicted by the isotropic von Karman model while the Mann model appears to overestimate this cross-coherence.
Climate variability on the Yucatan Peninsula (Mexico) during the past 3500 years, and implications for Maya cultural evolution

Climate variability on the Yucatan Peninsula during the past 3500 yrs is reconstructed from the measurement of δ18O in monospecific ostracods and gastropods in a 6.3-m sediment core from Lake Punta Laguna, Mexico. This late Holocene record is divided into three periods based on changes in mean δ18O values. From ∼3310 to ∼178514C yr B.P. (Period I), low mean δ18O values indicate relatively wet conditions (i.e., low evaporation to precipitation ratio,E/P). Mean oxygen isotopic values increased ∼178514C yr B.P., and the interval between ∼1785 and ∼93014C yr B.P. (Period II) was distinctly drier than the periods before or after. The climate during the latter part of Period II was persistently dry, with exceptionally arid events centered at ∼1171, 1019, and 94314C yr B.P. (equivalent to 862, 986, and 1051 A.D.). This interval of frequent drought was recorded at several other localities in Mexico and Central America, and coincided with the collapse of Classic Maya civilization. Following the last arid event, δ18O values decreased abruptly at ∼93014C yr B.P. (beginning of Period III), signaling a return to wetter conditions that have generally prevailed to the present, with the exception of a dry episode centered at 55914C yr B.P. (1391 A.D.). The paleoclimatic record from Punta Laguna provides evidence that multi-decadal and millennial-scale changes inE/Poccurred on the Yucatan Peninsula during the late Holocene. These wet/dry episodes may have influenced cultural evolution in Mesoamerica.
Radiometric Measurements of Temperature Profiles in the Planetary Boundary Layer

Abstract A ground-based 5-mm wavelength radiometer, named the Radiometric Thermasonde, has been developed. Typical vertical temperature profiles, derived from a recently developed radiometric data processing technique, are compared with profiles measured simultaneously by conventional techniques. Two years of performance testing of the operational prototype Thermasonde have demonstrated the feasibility of using radiometric remote probing techniques to describe thermal stability conditions within the first 1.5–2.0 km above the surface, during fair weather conditions. Preliminary tests indicate that temperature profiles derived from the Thermasonde can provide useful information, particularly for air pollution meteorology, for describing dispersion characteristics within the planetary boundary layer. The evaluation of a preliminary data reduction technique is described.
Importance of wind conditions, fetch, and water levels on wave-generated shear stresses in shallow intertidal basins

[1] Wave-generated shear stresses are the main mechanism responsible for sediment erosion on tidal flats and regulate both sediment concentrations in the water column and, together with tidal currents, sediment export to salt marshes and to the ocean. We present herein a simple method to estimate sediment erosion potential in shallow tidal basins caused by wind wave events. The method determines the aggregate response of the entire basin, combining in a simple framework the contribution from different landscape units. The method is applied to a system of shallow tidal basins along the Eastern Shore of Virginia, USA. Our analysis unravels the interplay of basin morphology, tidal elevation, and wind direction on water depth, fetch, and the resulting wave-generated shear stresses. We identify four bottom shear stress regimes as a function of water elevation produced by wind waves in shallow micromesotidal systems. For water elevations below mean lower low water (MLLW), an increase in fetch is counteracted by an increase in depth, so that the average bottom shear stress and erosion potential is maintained constant. For elevations between MLLW and mean sea level (MSL), the increase in water depth dominates the increase in wave height, thus reducing the bottom shear stresses. For elevations between MSL and mean higher high water (MHHW), the range associated with stable salt marsh platforms, flooding of salt marshes increases fetch, wave height, and bottom shear stresses, producing the largest resuspension events in the bay. For elevations above MHHW, the increase in depth once again dominates increases in wave height, thereby reducing average bottom shear stresses and potential erosion.
Determination of Interaction Sites on the Small G Protein RhoA for Phospholipase D

Phospholipase D (PLD) has been identified as a target of small G proteins of the Rho family. The present study was directed at defining the interaction sites of RhoA with rat brain PLD in vitro using chimeric proteins between RhoA and Ha-Ras or Cdc42Hs and point mutations. The switch I region of RhoA, which is the common effector domain of Ras-like G proteins, was a crucial interaction site for PLD. Mutations in conserved amino acids (Tyr34, Thr37, Phe39) totally abolished PLD activation, while mutations in Val38 or Tyr42 caused partial loss. Two additional sites were responsible for the differential PLD activation ability between RhoA and Cdc42Hs. Changing Asp76 in the switch II region of RhoA to the corresponding amino acid in Cdc42Hs led to partial loss of PLD activation. A chimeric protein with the N-terminal third of Cdc42Hs changed to RhoA showed enhanced PLD activation. Analysis of other Rho/Ha-Ras chimeric proteins and mutations indicated that Gln52 adjacent to the switch II region is responsible for this gain of function. In conclusion, the present study shows that conserved amino acids in the switch I region of RhoA are major PLD interaction sites and that residues in the switch II and internal regions are responsible for the differential activation of PLD by RhoA and Cdc42Hs.
Wave attenuation by flexible, idealized salt marsh vegetation

Abstract Wave attenuation by vegetation is a highly dynamic process and its quantification is important for understanding shore protection potential and modeling coastal hydrodynamics. Data documenting the interactions of Spartina alterniflora , represented by polyolefin tubing, and single- and double-peaked irregular waves were collected in a large-scale laboratory flume. The laboratory provided a controlled environment to evaluate wave attenuation, including the parameters of stem density, submergence, wave height, and peak period. Wave attenuation appeared to be most dependent on stem density and the ratio of stem length to water depth. Wave attention increased slightly with wave height while no clear trend with respect to wave period was seen. Treating double-peaked spectra as superimposed wave systems revealed a preferential dissipation of the higher-frequency wave system relative to the lower-frequency wave system under emergent conditions. Wave energy loss occurred at all frequencies of both spectral types, with dissipation increasing with frequency above the spectral peak. Parameterizing the spectral equilibrium range as a function of frequency showed a steepening of the spectral tail compared to the − 4 power law under emergent conditions. An empirical relationship defining the bulk drag coefficient for S. alterniflora as a function of the stem Reynolds number is found to serve as a first estimate for engineering applications.
An Evaluation of Visual Interfaces for Teleoperated Control of Kinematically Redundant Manipulators

The utilization of robots in hazardous environments for tasks that require high safety and/or precision is significantly increasing. In this work, we consider scenarios where kinematically redundant manipulators are teleoperated to complete tasks specified by point-to-point motion. Teleoperator performance is evaluated based on several different criteria. We build upon previous work on the performance of human/robotic systems by studying the effects of two different visual interfaces. Namely, we compare a world view with an eye-in-hand view and evaluate how these two different visual interfaces affect human performance and task completion.
Headwater streams and forest management: does ecoregional context influence logging effects on benthic communities?

Effects of forest management on stream communities have been widely documented, but the role that climate plays in the disturbance outcomes is not understood. In order to determine whether the effect of disturbance from forest management on headwater stream communities varies by climate, we evaluated benthic macroinvertebrate communities in 24 headwater streams that differed in forest management (logged-roaded vs. unlogged-unroaded, hereafter logged and unlogged) within two ecological sub-regions (wet versus dry) within the eastern Cascade Range, Washington, USA. In both ecoregions, total macroinvertebrate density was highest at logged sites (P = 0.001) with gathering-collectors and shredders dominating. Total taxonomic richness and diversity did not differ between ecoregions or forest management types. Shredder densities were positively correlated with total deciduous and Sitka alder (Alnus sinuata) riparian cover. Further, differences in shredder density between logged and unlogged sites were greater in the wet ecoregion (logging × ecoregion interaction; P = 0.006) suggesting that differences in post-logging forest succession between ecoregions were responsible for differences in shredder abundance. Headwater stream benthic community structure was influenced by logging and regional differences in climate. Future development of ecoregional classification models at the subbasin scale, and use of functional metrics in addition to structural metrics, may allow for more accurate assessments of anthropogenic disturbances in mountainous regions where mosaics of localized differences in climate are common.
Drawing of ultrahigh molecular weight polyethylene fibers in the presence of supercritical carbon dioxide

The drawing behavior of ultrahigh molecular weight polyethylene fibers in supercritical carbon dioxide (scCO 2) is compared to that in air at different tempera- tures. The temperature substantially influences the drawing properties in air, whereas in scCO 2, a constant draw stress and tensile strength are observed. Differential scan- ning calorimetry shows an apparent development of a hexagonal phase along with a significant increase in the crystallinity of air-drawn samples with increasing temper- ature. The existence of this phase is not confirmed by wide-angle X-ray scattering, which instead shows that air-drawn samples crystallize in an internally constrained manner. In contrast, scCO 2 allows crystals to grow without constraints through a possible crystal- crystal transformation, increasing the processing temperature to 110
Direct conversion/superheterodyne W-CDMA baseband down-link channel

A configurable W-CDMA baseband down-link (BDL) channel suitable to be used with both direct conversion (DIR) and superheterodyne (SHT) architectures has been integrated in a double-poly 0.6/spl mu/m CMOS technology. The BDL is an analog signal processor consisting of calibrated active-RC filters and oversampled 6-bit analog-to-digital pipeline converters, which sufficiently suppresses the adjacent channel and other interferers before digital-signal processing on an external DSP. The designed BDL channel achieves 38.4dB-SNDR, 43dB-SFDR in DIR mode and 38.3dB-SNDR, 42.8dB-SFDR in SHT mode with an overall power consumption of only 49mW/58mW (DIR/SHT) from a single 2.8V power supply. A low power consumption mode allows to further reduce these values down to 41mW/50mW (DIR/SHT) without significant detrimental effects to BDL linearity performance.
Changing Roles: Coaching Models For Restructuring Schools

How do roles and relationships in schools change in restructuring schools? What problems are encountered by schools as a result of changing roles as schools attempt to implement restructuring? And how can the process be improved?
Realistic Reflections and Refractions on Graphics Hardware with Hybrid Rendering and Layered Environment Maps

We introduce hybrid rendering, a scheme that dynamically ray traces the local geometry of reflective and refractive objects, but approximates more distant geometry by hardwaresupported environment maps (EMs). To limit computation, we use a greedy ray path shading model that prunes the binary ray tree generated by refractive objects to form just two ray paths. We also restrict ray queries to triangle vertices, but perform adaptive tessellation to shoot additional rays where neighboring ray paths differ sufficiently. By using layered, parameterized EMs that are inferred over a set of viewpoint samples to match ray traced imagery, we accurately handle parallax and view-dependent shading in the environment. We increase robustness of EMs by inferring them simultaneously across multiple viewpoints and including environmental geometry that is occluded from the viewpoint sample but is revealed in nearby viewpoints. We demonstrate realistic shiny and glass objects with a user-controlled viewpoint.
Geminin Functions Downstream of p53 in K-ras-Induced Gene Amplification of Dihydrofolate Reductase

DNA strand breakage and perturbation of cell cycle progression contribute to gene amplification events that can drive cancer. In cells lacking p53, DNA damage does not trigger an effective cell cycle arrest and in this setting promotes gene amplification. This is also increased in cells harboring oncogenic Ras, where cell cycle arrest is perturbed and ROS levels that cause DNA single strand breaks are elevated. This study focused on the effects of v-K-ras and p53 on MTX-mediated DHFR amplification. Rat lung epithelial cells expressing v-K-ras or murine lung cancer LKR cells harboring active K-ras continued cell cycle progression when treated with MTX. However, upon loss of p53, amplification of DHFR and formation of MTX-resistant colonies occurred. Expression levels of cyclin A, Geminin, and Cdt1 were increased in v-K-ras transfectants. Geminin was sufficient to prevent the occurrence of multiple replications via interaction with Cdt1 after MTX treatment, and DHFR amplification proceeded in v-K-ras transfectants that possess a functional p53 in the absence of geminin. Taken together, our findings indicate that p53 not only regulates cell cycle progression, but also functions through geminin to prevent DHFR amplification and protect genomic integrity.
A multimedia MAC protocol for distributed DS mobile radio networks

This paper presents a distributed multimedia media-access control protocol that is specifically designed for half-duplex radios and direct-sequence signaling. Each radio can transmit and receive random-access data and simultaneously support several virtual-circuit connections. A reservation-based approach with active acknowledgments is used for the transmission of random-access data. Virtual-circuit data is transmitted periodically, and associated with each virtual circuit connection are periodically broadcast control packets containing channel-access information. The content of the control packets is used by other radios to avoid contention. Numerical results show that the protocol outperforms a number of related alternatives.
An extended simplified reference tissue model for the quantification of dynamic PET with amphetamine challenge.

Abstract Background: Equilibrium analysis to quantify dynamic positron emission tomography (PET) with bolus followed by continuous tracer infusion and acute amphetamine challenge assumes that all tissue kinetics attain steady states during pre- and post-challenge phases. Violations of this assumption may result in unreliable estimation of the amphetamine-induced percent change in the binding potential (ΔBP%). Method: We derived an extended simplified reference tissue model (ESRTM) for modeling tracer kinetics in the pre- and post-challenge phases. Ninety-minute [11C]raclopride PET studies with bolus injection followed by continuous tracer infusion were performed on 18 monkeys and 2 baboons. Forty minutes after the bolus injection, a single acute intravenous amphetamine administration was given of 2.0 mg/kg to monkeys and of 0.05, 0.1, 0.5, and 1.5 mg/kg to baboons. Computer simulations further evaluated and characterized the ESRTM. Results: In monkey studies, the ΔBP% estimated by the ESRTM was 32 ± 11, whereas, the ΔBP% obtained using the equilibrium methods was 32% to 81% lower. In baboon studies, the ΔBP% values estimated with the ESRTM showed a linear relationship between the ΔBP% and the natural logarithm of amphetamine dose (R2 = 0.96), where the ΔBP% = 10.67Ln(dose) + 33.79 (0.05 ≤ dose in mg/kg ≤ 1.5). At 1.5 mg/kg amphetamine, the ΔBP% estimates from equilibrium methods were 18% to 40% lower than those estimated by the ESRTM. Results showed that the nonsteady state of tracer kinetics produced an underestimation of the ΔBP% from the equilibrium analysis. The accuracy of the ΔBP% estimates from the equilibrium analysis was significantly improved by the ESRTM. The ΔBP% estimated by the ESRTM in the study was consistent with that from previous [11C]raclopride PET with amphetamine challenge. Conclusion: In conclusion, the ESRTM is a robust kinetic modeling approach and is proposed for the quantification of dynamic PET with acute amphetamine stimulation.
CMOS magnetic actuators for bio-material manipulation

Magnetic manipulation for molecular-level interrogation and diagnosis are emerging as lab-on-chip platforms. These platforms necessitate low-cost, low-power, portable, and high efficiency integrated implementations. We Implement an all-integrated programmable 16×16 magnetic coil array chip with a die-size of 1.5×1.5mm2 designed in bulk CMOS 0.5μm 3M2P technology. The integrated design does not require any external magnetic source. It relies on the Hall effect generated by the smallest permissible vertical coil inductors (in this reported technology, the inductor's planar area is 6μm×6μm). The coil array is selectively and dynamically controlled. Each cell, composed of the coil and its logical control circuitry, can emit eight programmable magnetic field levels. All array components are tuned to work at 900MHz and incorporate highspeed serial row/column switching. The array can be used to manipulate a small, in the order of 6μm×6μm, single molecule or in collaborative manipulation of larger bio-material objects.
Neutron Diffraction Studies of High TC Superconductors

We have investigated the structure and composition of La2CuO4 (both pure and Sr-doped) and Nd(Ba2−xNdx)Cu3O7 using powder neutron diffraction. In La2−xSrxCuO4, Tc reacnes its maximum at x=0.15, after which vacancies are introduced in the 2D planes and superconductivity is destroyed. Superconductivity in La2CuO4 is not bulk. No evidence for nonstoichlometry in this material can be observed. In the Nd(Ba2−xNdx)Cu3O7 system, Tc is a complex function of oxygen ordering and electronic effects.