cssi/SciSciGPT-SciSciNet huggingface dataset:
Investigation of exchange couplings in [Fe3S4]+ clusters by electron spin-lattice relaxation

We have studied four proteins containing oxidized 3Fe clusters ([Fe3S4]+, S=1/2, composed of three, antiferromagnetically coupled high-spin ferric ions) by continuous wave (CW) and pulsed EPR techniques: Azotobacter vinelandii ferredoxin I, Desulfovibrio gigas ferredoxin II, and the 3Fe forms of Pyrococcus furiosus ferredoxin and aconitase. The 35 GHz (Q-band) CW EPR signals are simulated to yield experimental g tensors, which either had not been reported, or had been reported only at X-band microwave frequency. Pulsed X- and Q-band EPR techniques are used to determine electron spin-lattice (T 1, longitudinal) relaxation times at several positions on the samples’ EPR envelope over the temperature range 2–4.2 K. The T 1 values vary sharply across the EPR envelope, a reflection of the fact that the envelope results from a distribution in cluster properties, as seen earlier as a distribution in g 3 values and in 57 Fe hyperfine interactions, as detected by electron nuclear double resonance spectroscopy. The temperature dependence of 1/T 1 is analyzed in terms of the Orbach mechanism, with relaxation dominated by resonant two-phonon transitions to a doublet excited state at ∼20 cm−1 above the doublet ground state for all four of these 3Fe proteins. The experimental EPR data are combined with previously reported 57Fe hyperfine data to determine electronic spin exchange-coupling within the clusters, following the model of Kent et al. Their model defines the coupling parameters as follows: J 13 = J, J 12 = J(1+ɛ′), J 23 = J(1+ɛ), where J ij is the isotropic exchange coupling between ferric ions i and j, and ɛ and ɛ′9 are measures of coupling inequivalence. We have extended their theory to include the effects of ɛ′≠ 0 and thus derived an exact expression for the energy of the doublet excited state for any ɛ, ɛ′. This excited state energy corresponds roughly to ɛJ and is in the range 5–10 cm−1 for each of these four 3Fe proteins. This magnitude of the product ɛJ, determined by our time-domain relaxation studies in the temperature range 2–4 K, is the same as that obtained from three other distinct types of study: CW EPR studies of spin relaxation in the range 5.5–50 K, NMR studies in the range 293–303 K, and static susceptibility measurements in the range 1.8-200 K. We suggest that an apparent disagreement as to the individual values of J and ɛ be resolved in favor of the values obtained by susceptibility and NMR (JE ≳200 cm−1 and ɛ ≳200 cm−1), as opposed to a smaller J and larger ɛ as suggested in CW EPR studies. However, we note that this resolution casts doubt on the accepted theoretical model for describing the distribution in magnetic properties of 3Fe clusters.
Presidential greatness and performance: Can we predict leadership in the White House?1

Two related questions regarding presidential leadership are addressed. First, what are the principal determinants of the rated greatness of American presidents? Second, can presidential performance be predicted using preelection biographical variables? Reliable measures of greatness and performance were operationalized for the 38 presidents of the United States, along with numerous potential predictors suggested by past literature on leadership, achieved eminence, and presidential popularity and greatness. About 75% of the variance in presidential greatness can be predicted using administration duration, number of war years, unsuccessful assassination attempts, scandals, and prepresidential publication record. Family background, personal characteristics, education, occupation, and political experiences provided few if any viable predictors of presidential performance, although succession to office through the vice-presidency exerted a rather general negative impact.
Particle Acceleration by the Sun: Electrons, Hard X-rays/Gamma-rays

Observations of hard X-ray (HXR)/γ-ray continuum and γ-ray lines produced by energetic electrons and ions, respectively, colliding with the solar atmosphere, have shown that large solar flares can accelerate ions up to many GeV and electrons up to hundreds of MeV. Solar energetic particles (SEPs) are observed by spacecraft near 1 AU and by ground-based instrumentation to extend up to similar energies, but it appears that a different acceleration process, one associated with fast Coronal Mass Ejections (CMEs) is responsible. Much weaker SEP events are observed that are generally rich in electrons, 3He, and heavy elements. The energetic particles in these events appear to be similar to those accelerated in flares. The Ramaty High Energy Solar Spectroscopic Imager (RHESSI) mission provides high-resolution spectroscopy and imaging of flare HXRs and γ-rays. The observations of the location, energy spectra, and composition of the flare accelerated energetic particles at the Sun strongly imply that the acceleration is closely related to the magnetic reconnection that releases the energy in solar flares. Here preliminary comparisons of the RHESSI observations with observations of both energetic electrons and ions near 1 AU are reviewed, and the implications for the particle acceleration and escape processes are discussed.
Alkaline pH changes in the cerebellum of asymptomatic HIV-infected individuals.

Human immunodeficiency virus (HIV) infection of the brain causes a complex cascade of cellular events involving several different cell types that eventually leads to neuronal cell death and the manifestation of the AIDS-associated dementia complex (ADC). Upon autopsy HIV-infected individuals show lesions within subcortical regions of the brain, including the cerebellum. Previously we have demonstrated, in primary and cell culture models of rat and human astrocytes, a change in intracellular pH (pH(i)) due to increased Na(+)/H(+) exchange following exposure to inactivated virus or gp120, the major HIV envelope glycoprotein. To further investigate whether any such in vivo pH(i) changes occur in human brains subsequent to HIV infection, we measured the pH(i) of the cerebellum in eight HIV-positive individuals and nine healthy volunteers using (31)P magnetic resonance spectroscopy imaging (MRSI) at high field strength (4.1 T). The results showed a significant difference between the age-adjusted mean pH(i) in the cerebellum in control group and patient groups (7.11 +/- 0.03 vs 7.16 +/- 0.04), and further HIV-infected individuals displayed a significant increase in the number of cerebellar volume elements that were alkaline. We hypothesize that this propensity towards alterations in cerebellar pH(i) may portend later neurological involvement resulting from HIV infection.
Egg-laying of the golden silk spider, Nephila clavipes L. (Araneae, Araneidae): Functional analysis of the egg sac

Abstract The egg-laying sequence of the orb-weaving spider Nephila clavipes was observed in the field setting. The functions of certain modal characteristics of the egg sac were assessed through the collection of normative field data on overwintering egg sacs and through the effects of egg sac manipulations on spiderling production. Components of the egg sac were manipulated before and after egg hatching to determine if they promoted offspring survival at different times in development. Naturally occurring and induced changes in the position and structure of the egg sac resulted in similar decreases in productivity. Certain components of the egg sac were important primarily before hatching, and others throughout the entire overwintering period. These results and the limitations of functional analyses of behaviours are discussed.
Inhibition of growth of human small cell and non-small cell lung carcinomas by antagonists of growth hormone-releasing hormone (GH-RH).

Insulin-like growth factors-I and-II (IGF-I and IGF-II) may be involved in the proliferation of human lung carcinomas. The purpose of this study was to investigate the effects of two potent antagonists of growth hormone-releasing hormone (GH-RH), MZ-4-71 and MZ-5-156 on the growth of the H69 human small cell lung cancer (SCLC) and H157 non-SCLC (NSCLC) lines transplanted into nude mice or cultured in vitro. Nude mice bearing H69 and H157 tumors were treated for 3-5 weeks with MZ-4-71 or MZ-5-156 injected s.c. twice a day at a dose of 20 mu g/animal. Growth of H69 and H157 tumors in nude mice was significantly inhibited by MZ-4-71 and MZ-5-156 as shown by a reduction in tumor volume and weight. In animals bearing H157 NSCLC, treatment with MZ-4-71 decreased IGF-I and IGF-II levels in tumor tissue. Levels of IGF-I, but not of IGF-II in serum and liver tissue of H157 tumor-bearing nude mice treated with MZ-4-71 were decreased. High affinity binding sites for ICF-I were demonstrated on membranes of H69 and H157 tumors. In cell cultures, the proliferation rate of H69 SCLC cells was suppressed by 10(-7)-10(-5) M MZ-4-71, but H157 NSCLC line was only inhibited by 10(-5) M antagonist. Our findings demonstrate that the GHRH antagonists MZ-4-71 and MZ-5-156 can inhibit the growth of SCLC and NSCLC. This new approach to the management of lung cancer merits further investigation.
Viscoelastic analysis of processing-induced residual stresses in thick composite laminates

Residual stresses induced during the processing of thick composite laminates are analyzed. A two-dimensional thermochemical analysis is used to obtain temperature and degree of cure distributions during cure. A two-dimensional finite-element model is developed to predict the residual stress history in rectangular laminated plates. A cure-dependent visco-elastic material model is used in the analysis. Both unidirectional and cross-ply laminates are investigated. Unidirectional laminates are studied because residual stresses in this class of laminates is driven purely by thickness effects. Regardless of the layup,for moderately thick (2.54-cm) laminates the nonuniformities in temperature and degree of cure are mild. As a result, the development of residual stress is very similar to the analysis of thin laminates. For laminates of large thickness (7.5 cm), stronger variations in temperature and degree of cure develop during the cure cycle. The development of residual stress in this case is more complex. The ...
Controlled Growth of Single-Walled Carbon Nanotubes from an Ordered Mesoporous Silica Template

We have grown carbon nanotubes (CNTs) with controlled orientation and diameter (1−4 nm) from thermally stable, highly ordered mesoporous SiO2 thin films by methane chemical vapor deposition (CVD). Controlled incorporation of an Fe precursor into one-dimensional (1D) and three-dimensional (3D) pore channels of mesoporous SiO2 results in a nanostructure catalytically active for CNT growth and stable to typical CVD temperatures. Growth of CNTs starts within the mesoporous SiO2, whose pore direction and pore dimension play an important role in controlling the orientation and diameter of the CNTs at the early stage of the growth. Lateral growth across micropatterned trenches results in oriented CNT assemblies with controlled tube dimension. The flexibility of constructing parallel nanotube assemblies and nanotube junctions by this simple method suggests its high potential for fabricating future integrated molecular electronic nanodevices.
On decision making in tomography

The author argues that although decision-making operations are not viewed as part of computerized tomography proper, it is possible to incorporate decision-making operations into reconstruction algorithms. Moreover, doing that will result in solutions more precise than the solutions obtained with the traditional two-step approach. The discussion attempts to demonstrate that it is possible to develop algorithms producing various attributes of reconstructed images or other images related to them directly from the projection data. These ideas are illustrated through examples. >
Two port characterization of DC to DC resonant converters

An analytical method based on two-port network theory is developed for DC-to-DC resonant converters. Based on steady-state frequency-domain analysis, a simple two-port model described by g-parameters is presented for these converters. The results obtained are useful for simulation and design of the converters. Simulation results are presented to support the method developed. >
Foreign aid, growth and poverty: A policy framework for Niger

Abstract This paper extends the dynamic macroeconomic framework developed by Agenor et al. [Agenor, P. -R., Bayraktar, N., & Aynaoui, K. E. (2006, July). Roads out of Poverty? Assessing the Links between Aid, Public Capital, Growth, and Poverty Reduction. World Bank, Revised.]. As in the original model, linkages between foreign aid, public investment (education, infrastructure, and health) and growth are explicitly captured, but this time in a fixed nominal exchange rate regime. Although the nominal exchange rate is fixed, the relative price of domestic goods is endogenous, thereby allowing for potential Dutch disease effects associated with increases in aid. The impact of policy shocks on poverty is assessed by using partial growth elasticities. A policy experiment of increasing foreign aid illustrates the dynamic trade-offs between growth and poverty reduction in Niger.
Effect of electron-ion collisions on generation of ionospheric irregularities by thermal source

On montre que les collisions electron-ion amortissent les sources thermiques et on determine les seuils d'instabilite dans la generation des irregularites ionospheriques d'echelle depassant la vingtaine de metres
Sexually Transmitted Disease Partner Notification among African-American, Adolescent Women

Objective. To better understand preferences and practices regarding partner notification of sexually transmitted infection (STI) among female, African-American adolescents. Methods. Participants completed a questionnaire and STI testing at baseline. Those diagnosed with Chlamydia or gonorrhea were recruited for a follow-up study, involving another questionnaire and repeat STI testing after three months. Results. At baseline, most participants (85.1%) preferred to tell their partner about an STI diagnosis themselves instead of having a health care provider inform him, and 71.0% preferred to bring their partner for clinic treatment instead of giving him pills or a prescription. Two-thirds of participants were classified as having high self-efficacy for partner notification of a positive STI diagnosis. In the multivariable analysis, older participants and those with fewer lifetime sexual partners were more likely to have high self-efficacy. Ninety-three participants (26.6%) had Chlamydia or gonorrhea and, of this subset, 55 participated in the follow-up study. Most adolescents in the follow-up study (76.4%) notified their partner about their infection. Conclusion. Although participants were willing to use most methods of partner notification, most preferred to tell partners themselves and few preferred expedited partner therapy. Traditional methods for partner notification and treatment may not be adequate for all adolescents in this population.
Contribution of biomass burning to atmospheric polycyclic aromatic hydrocarbons at three European background sites.

Radiocarbon analysis of atmospheric polycyclic aromatic hydrocarbons (PAHs) from three background areas in Sweden, Croatia, and Greece was performed to apportion their origin between fossil and biomass combustion. Diagnostic ratios of PAHs implied that wood and coal combustion was relatively more important in the northern European site, while combustion of fossil fuels was the dominant source of PAHs to the two central−southern European background sites. The radiocarbon content (Δ14C) of atmospheric PAHs in Sweden ranged between −388‰ and −381‰, while more depleted values were observed for Greece (−914‰) and Croatia (−888‰). Using a 14C isotopic mass balance model it was calculated that biomass burning contributes nearly 10% of the total PAH burden in the studied southern European atmosphere with fossil fuel combustion making up the 90% balance. In contrast, biomass burning contributes about 50% of total PAHs in the atmosphere at the Swedish site. Our results suggest that the relative contributions of bio...
Spanish slurs and stereotypes for Mexican-Americans in the USA: A context-sensitive account of derogation and appropriation

Slurs such as spic, slut, wetback, and whore are linguistic expressions that are primarily understood to derogate certain group members on the basis of their descriptive attributes (such as their race or sex) and expressions of this kind have been considered to pack some of the nastiest punches natural lan- guage affords. Although prior scholarship on slurs has uncovered several im- portant facts concerning their meaning and use -including that slurs are poten- tially offensive, are felicitously applied towards some targets yet not others, and are often flexibly used not only derogatorily to convey offense towards out-group members but also non-derogatorily to convey affiliation with in- group members- the literature remains largely focused on slurs that typically target African Americans (nigger), male homosexuals (faggot), and sexually ac- tive females (slut). Since no account of slurs that typically target Hispanics or Mexican-Americans has so far been proposed, here I offer the first systematic and empirically informed analysis of these that accounts for both their deroga- tory and appropriative use. Importantly, this article reviews over a dozen Span- ish stereotypes and slurs and explains how the descriptive attributes involved in a stereotype associated with a slur can contribute to the predication of cer- tain content in the application of that slur toward its target in context. This article further explains how the psychological effects of stereotype threat and stereotype lift can be initiated through the application of a relevant slur towards its target in context as well.
Inner-City Single Black Mothers’ Gender-Related Childrearing Expectations and Goals

Semi-structured interviews with nine U.S. Midwestern inner-city single Black mothers of young children were analyzed using inductive qualitative methods to determine similarities and differences in their expectations and goals for sons versus daughters. Drawing on critical race feminism, we developed links between these ideas, mothers’ personal experiences with men, and prevailing Black gender ideologies. Mothers valued independence and strength in daughters and hoped to prevent early sexual activity. Mothers with sons couched their aspirations in terms of counter-examples but were fatalistic. Childrearing goals reflected fears based on personal experiences.
Use of combined biological and chemical purification procedures in the separation of follicle-stimulating hormone from rat pituitary tissue.

In the rat, orchidectomy, followed by androgen and thyroglobulin treatment, increased the FSH content of the adenohypophysis, while decreasing its LH and TSH contents. Use of glands prepared in this way, for the biochemical purification of FSH, yielded a final product with a higher FSH⁄LH ratio (> 160,000: 1) than any other FSH preparation yet reported, regardless of the species of origin. (Endocrinology 87: 201, 1970) BECAUSE of the small size of the rat adenohypophysis, discouragingly large numbers of rat pituitary glands are needed for the extraction and purification procedures (1) used to separate follicle-stimulating hormone (FSH) from the other pituitary glycoprotein hormones: LH (luteinizing hormone) and TSH (thyroid-stimulating hormone). The study we are reporting had 2 objectives: first, to see whether a combination of treatments could be developed which would increase the FSH content of rat adenohypophysis in vivo, while decreasing its LH and TSH contents; second, to see whether highly purified ...
Predicting intrinsic clearance for drugs and drug candidates metabolized by aldehyde oxidase

Metabolism by aldehyde oxidase (AO) has been responsible for a number of drug failures in clinical trials. The main reason is the clearance values for drugs metabolized by AO are underestimated by allometric scaling from preclinical species. Furthermore, in vitro human data also underestimates clearance. We have developed the first in silico models to predict both in vitro and in vivo human intrinsic clearance for 8 drugs with just two chemical descriptors. These models explain a large amount of the variance in the data using two computational estimates of the electronic and steric features of the reaction. The in vivo computational models for human metabolism are better than in vitro preclinical animal testing at predicting human intrinsic clearance. Thus, it appears that AO is amenable to computational prediction of rates, which may be used to guide drug discovery, and predict pharmacokinetics for clinical trials.
“I will walk away on my own, phantom-footed”: Judith Ortiz Cofer’s Invocation of the Constant Move

Cultural production in the diaspora foregrounds themes of movement, border crossing, and the struggle over what and where home should be. To venture onto the road (or onto the airplane) and to grapple with the concept of home are key experiences for Puerto Rican Americans. For Jorge Duany, Puerto Rican realities are constructed to a large degree by the experience of el vaiven, or the back-and-forth movement “of people [that] creates a porous border zone” (“Nation on the Move” 19). Traveling over the western Atlantic in a pattern of pendular migrations is a striking example of the “spreading of seed,” as the Greek roots of the word diaspora suggest (Otero 276). Among the artistic responses to this experience is a nostalgic and ultimately conservative placing of a past home in a present space. Texts by some writers of the early Nuyorican movement, such as Piri Thomas or the poets published in Miguel Algarin and Miguel Pinero’s Nuyorican Poetry: An Anthology of Puerto Rican Words and Feelings (1975), relocate the island home to New York City as a means of self-defense and self-affirmation. Other authors, rejecting the idea of a newfound physical home, contend that the notion of a home for the exiled is only possible in literature. In recent texts, a new interpretation of the idea of home in diaspora has emerged: instead of, on the one hand, a transferred, idealized, or suspended home between the present and the past, or on the other hand, a home bound to a written text, authors propose the model of home as movement. The notion of dwelling, they suggest, does not necessarily have to be associated with the concepts of stasis and origin; instead, it may also be constituted through travel. A case in point is the writing of Puerto Rican American author Judith Ortiz Cofer. This essay charts the presentation and signification of movement in several of her works; it focuses on Ortiz Cofer’s elaboration of the act of walking in order to argue that it is through such physical and individual exercise that her characters create mobile spaces of residence. Although the notion of home is present in diverse ways in Ortiz Cofer’s texts, the description of a home in motion has become a key motif in her more recent work, especially in her poetry. Such an account of dwelling in travel is different from what has become one of the central critical concepts in this field, Gilles Deleuze’s and Felix Guattari’s notion of nomadology. According to the two philosophers, nomadology entails a radical deterritorialization (Qu’est-ce 186). The nomadic subject travels through spaces of no horizon, without “any . . . generic axis or deep structure” (“Rhizome” 101). Language, in their view, does not connect spaces; it is a decentering force itself. In contrast, the notion of home is not abandoned in Ortiz Cofer’s writing but remains a central point of reference—although in a decidedly new fashion, echoing
Relationships between Heart Rates and Behavior of Goats in Encounters with People

Heart rates, vocal repetition rates and avoidance behavior were simultaneously monitored in human-reared (HR) and dam-reared (DR) goats during 5-min encounters with other goats or with a stationary person. No consistent relationships between heart rates and changes in behavior were found. A significant difference between HR and DR goats in vocal rates during encounters with other goats was not accompanied by group differences in heart rates. Within the HR group, mean vocal rates in encounters with goats and with a person decreased from 21.3 to 0.6 vocalizations min−1, respectively, with no concommitant changes in heart rates. Correlations between heart rates and behavior were not significant in either type of test encounter. Based on observed behavior, DR goats could be considered to be fearful of people, yet their heart rates were not significantly different from HR goats which were not fearful. Complex relationships between emotional behavior and emotional state make it difficult to objectively assess fear and distress from data on heart rates and vocal behavior.
Macrophages within the granulomas of murine Schistosoma mansoni are a source of a somatostatin 1–14-like molecule

Abstract Inflammatory cells secrete some neuropeptides that function as immunomodulators. Somatostatin has immunoregulatory properties. It is unknown whether immune cells make somatostatin. Intricate intercellular communications govern the granulomas of murine Schistosoma mansoni. These granulomas synthesize several neuropeptides. Thus, it was determined whether somatostatin is in these inflammatory lesions. Granulomas, which were isolated from the livers of infected mice, contained somatostatin 1–14 as shown by radioimmunoassay and chromatography. Immunostaining localized immunoreactive somatostatin and pre-prosomatostatin to granuloma macrophages. Granuloma macrophages cultured in vitro released immunoreactive somatostatin. Calcium ionophore A23187, which promotes macrophage secretion, increased somatostatin in the culture supernatants. Thus, the granulomas have a molecule with somatostatin 1–14-like properties that is possibly a secretory product of the granuloma macrophage.
Cultural Imperialism and Heritage Politics in the Event of Armed Conflict: Prospects for an ‘Activist Archaeology’

The production of archaeological knowledge is embedded in a long-standing tradition of colonial encounters. This paper asks how political-economic interests impinge on archaeological work, specifically in the event of armed conflict. To answer this question I discuss commodification of cultural heritage and analyze it as a form of structural violence. I argue that the attitude that allows treatment of archaeological artifacts as saleable items with international owners is part of a strategy of global cultural imperialism. Exemplified by the case of the US-led invasion of Iraq in 2003, this paper shows how the clash of global ‘heritage’ politics with local practices of memorializing the past results in a tension: because capitalist governments consider the locales whose glorious pasts are studied by archaeologists to be culturally inferior, the nexus between (trans-)national actors and local communities is an asymmetrical one. In order to overcome the hegemonic role of archaeology within these dynamics, I propose an ‘activist archaeology’ that enables a political activism grounded in recursivity.
Aquatic life at high altitude: Respiratory adaptations in the lake titicaca frog, Telmatobius culeus

Telmatobius culeus has a combination of behavioral, morphological and physiological adaptations which allows an aquatic life in cool (10 degrees C) O2-saturated (at 100 mm Hg) waters at high altitude (3812 m). The skin surgace area is increased by pronounced folds and the cutaneous capillaries penetrate to the outer layers of the skin. The erythrocyte volume (394 mu3) is the smallest reported for amphibians. The P50 (15.6 at ph 7.65 and 10 degrees C) is the lowest, and the erythrocyte count (729 - 103/mm3) the highest for an anuran. The O2 capacity (11.7 vol%), hemoglobin (8.1 g/100 ml), hemoglobin concentration (0.281 pg/mu3) and hematocrit (27.9%) measured at 18 degrees C and 3800 m are all elevated in comparison with most amphibians. The O2 dissociation curve is sigmoid (n = 2), the Bohr factor is small (deltalog P50/deltapH = -0.30) and the buffering capacity (-8.9 m M HCO3 - 1-1) is typical for an aquatic amphibian. The metabolic rate (14.1 mul -g-1-h-u) is the lowest reported for a frog and among amphibians only the giant salamanders (Amphiuma, Necturus and Siren) have lower values. If prevent from surfacing in hypoxic waters, the frogs ventilate the skin by "bobbing" behavior; if allowed to surface, they will ventilate the small lungs and the metabolic rate increases to 23 mul-g-1-h-1.
Coating the inside of a capillary of square cross section

Abstract Coating the walls of a capillary is usually done in two steps: (1) wetting or filling the capillary with a viscous fluid, and (2) clearing the capillary by forcing air through it. Clearing amounts to driving the wetting viscous fluid out of the capillary by another immiscible fluid. When air is blown into one end of a tube containing the viscous fluid, a “bubble” forms with the back end open. The bubble travels down the tube forcing some of the liquid out and leaving behind a fraction, in the form of a uniform film covering the walls. This paper reports flow visualization in capillaries of square cross secton. Visualization of the bubble was done by viewing both side and diagonal planes of the capillary in order to analyze the effect of the square cross section. Measurements from the captured images were used to characterize the shape of the fluid—fluid interface. The coating thickness of liquid deposited on the capillary walls was measured as the fraction of the capillary volume occupied by the liquid. The results for a wide range of capillary numbers show that this fraction increased monotonically with increasing capillary number, approaching an asymptotic limit of 0.64. Sequential particle tracking techniques were used to determine the flow field in different regions surrounding the bubble. A semi-quantitative comparison of the flow behavior, in capillaries of square and circular cross section, has been carried out.
Nicotine Blocks the Suckling-Induced Rise in Circulating Prolactin in Lactating Rats

In lactating rats the rapid suckling-induced release of pituitary prolactin into circulating blood is inhibited by a subcutaneous injection of nicotine. This treatment does not block the lesser "stress-induced" rise in prolactin in response to either. Although nicotine may impair milk production by its effect on prolactin release, it does not appear to block milk ejection from the lactating mammary gland.
Topological theory of hadrons. I. Mesons

Spin is incorporated into the hadronic topological expansion scheme. Spin analogs of Chan-Paton factors are introduced in a way that avoids the troubles encountered in earlier attempts. Those troubles, at the meson level, were, first, the occurrence of twice the wanted number of pseudoscalar and vector mesons; second, the occurrence of parity-doublet partners of the pseudoscalar and vector mesons; and third, the occurrence of these parity-doublet partners as particles of negative metric, called ghosts. These troubles are all avoided by introducing a new topological level, called zero entropy, that lies below the ordered level. At the zero-entropy level quarks of opposite chirality are treated as distinct particles. The theory has been extended to all hadrons, and the basic particles are exactly those of the constituent-quark model, which for baryons start with the (56/sup +/) and (70/sup -/). The theory is formulated in the M-function framework, where the ''quarks'' are represented by two-component spinors, and it entails SU(6)/sub W/ symmetry of the hadronic vertices at a low level of the topological expansion.
Predicting ambulatory blood pressure during school: effectiveness of social and nonsocial reactivity tasks in black and white adolescents.

We evaluated a newly developed stress task, the Social Competence Interview, and three nonsocial tasks (video game, mirror drawing, mental arithmetic) for ability to predict ambulatory blood pressure in 237 black and white adolescents. Blood pressure was measured in laboratory, classroom, and transition (between-class) settings. A resting laboratory baseline explained 10–49% of the variance in ambulatory blood pressure levels; the ability of the stress tasks to explain additional variance was assessed in multiple regression analyses. Only the blood pressure response to the interview enhanced prediction of classroom and transition systolic and diastolic pressures in the total sample and in blacks, whites, females, and males – even when the interview data were entered into a hierarchical regression model after those for the other three tasks were entered. Mirror drawing improved prediction of transition systolic blood pressure in the total sample, and mental arithmetic plus the interview improved prediction of classroom diastolic pressure in black males; however, video game failed to enter any predictive equation. Racial subgroup analyses disclosed that the interview data predicted systolic pressure in whites but predicted diastolic pressure in blacks, indicating biological differences in blood pressure regulation. An interview that elicits characteristic thoughts and social behaviors appears to represent a promising approach to examining environmental influences on blood pressure.
A sensitive, enzymatic assay for the detection of closely opposed cyclobutyl pyrimidine dimers induced in human diploid fibroblasts.

Abstract A sensitive, enzymatic assay has been developed for the detection of closely opposed cyclobutyl pyrimidine dimers induced in UV-irradiated human diploid fibroblasts. In this assay closely opposed dimers are detected as bifilar enzyme-sensitive sites. Single-strand incisions are made at the positions of individual pyrimidine dimers through the action of M. luteus pyrimidine dimer-DNA glycosylase. Incisions at closely opposed dimers, effectively expressed as double-strand breaks, are quantified from the resulting reduction in DNA double-strand molecular weight as determined by velocity sedimentation through neutral sucrose density gradients. The stability of the bacteriophage λ cos site under our reaction conditions indicates that opposed incisions must be relatively close to be expressed as a double-strand break. The dose response for the induction of bifilar enzyme-sensitive sites in mammalian cells was found to be complex but can be approximated by a function that increases as the 1.2–1.4 power of UV dose. The frequency of bifilar enzyme-sensitive sites observed decreased during postirradiation incubation of excision-repair-proficient human diploid fibriblasts with less than 20% still detectable at 24 h after irradiation with 5 J/m2 (254 nm). By comparison, over 80% of the bifilar enzyme-sensitive sites induced in fibroblasts assigned to xeroderma pigmentosum complementation group A remained detectable 24 h after irradiation. The implications of these results for models addressing the induction and repair of closely opposed pyrimidine dimers are discussed.
Beyond pheromones: evolving error-tolerant, flexible, and scalable ant-inspired robot swarms

For robot swarms to operate outside of the laboratory in complex real-world environments, they require the kind of error tolerance, flexibility, and scalability seen in living systems. While robot swarms are often designed to mimic some aspect of the behavior of social insects or other organisms, no systems have yet addressed all of these capabilities in a single framework. We describe a swarm robotics system that emulates ant behaviors, which govern memory, communication, and movement, as well as an evolutionary process that tailors those behaviors into foraging strategies that maximize performance under varied and complex conditions. The system evolves appropriate solutions to different environmental challenges. Solutions include the following: (1) increased communication when sensed information is reliable and resources to be collected are highly clustered, (2) less communication and more individual memory when cluster sizes are variable, and (3) greater dispersal with increasing swarm size. Analysis of the evolved behaviors reveals the importance of interactions among behaviors, and of the interdependencies between behaviors and environments. The effectiveness of interacting behaviors depends on the uncertainty of sensed information, the resource distribution, and the swarm size. Such interactions could not be manually specified, but are effectively evolved in simulation and transferred to physical robots. This work is the first to demonstrate high-level robot swarm behaviors that can be automatically tuned to produce efficient collective foraging strategies in varied and complex environments.
Thermal-gradient-induced non-mass-dependent isotope fractionation

Isotope fractionation resulting from gas diffusion along a thermal gradient has always been considered entirely mass-dependent. A previous report, however, showed that non-mass-dependent 17O anomalies can be generated simply by subjecting O2 gas in an enclosure to a thermal gradient. To explore the underlying mechanism for the anomalies, we tested the effect of gas pressure, duration of experiment, and geometry of the apparatus on the 17O anomalies for O2 as well as on the 33S or 36S anomalies for SF6 gas. The results are consistent with our proposal that a previously ignored nuclear spin effect on gas diffusion coefficient may be largely responsible for generating the observed anomalies. This discovery provides clues to some of the puzzling non-mass-dependent isotope signatures encountered in experiments and in nature, including the triple oxygen or quadruple sulfur isotope heterogeneity in the solar system. Copyright © 2011 John Wiley & Sons, Ltd.
CO formation in early stage high temperature benzene oxidation under fuel lean conditions: Kinetics of the initiation reaction, C6H6→C6H5→H

The oxidation of benzene under fuel-lean conditions has been studied from 1600 to 2300 K in a shock tube using a stabilized CW CO laser to monitor CO production. The result of the kinetic modeling of the CO formation according to the global mechanism of Fujii and Asaba indicates that the rate of CO formation in the early stage of oxidatin depends very sensitively on the rate-limiting unimolecular decomposition of benzene: C 6 H 6 → 1 C 6 H 5 + H The rate constant obtained for the initiation reaction using a scheme consisting of a set of 25 reactions is given by the following expression: k1=1015.70±0.52 exp (−54, 300±2200/T) sec−1. for the pressure range of 1.9–2.7 atm. The result of an RRKM calculation for the reaction indicated that at temperatures above 2000 K, k1 becomes slightly pressure-dependent. The extrapolation of the individual data with the RRKM theory led to k1∞≌1016.76±0.50exp (−58,400 ± 2200/T) sec−1.
Taylor factors in materials with many deformation modes

A Taylor factor (M) is frequently used to express a flow stress {sigma} measured in a polycrystal in terms of the critical resolved shear stress (CRSS) {tau} in the constituent single crystals. It is an average orientation factor which depends on the texture of the material and on the crystallographic nature of the assumed slip systems. When stress strain curves are analyzed, this Taylor factor is also commonly used to express the macroscopic strain in terms of the algebraic sum of crystallographic shears. As a result, the polycrystals strain hardening slope is proportional to M{sup 2}, and therefore rather sensitive to the assumed value of M. The strain hardening rate in single crystals, obtained by dividing the polycrystal value by M{sup 2}, provides useful information on the deformation mechanism and on constitutive relations to be used in polycrystal simulations.
Breaking bud dormancy in apple with a plant bioregulator, thidiazuron.

Abstract The effects of N-phenyl-N′-1,2,3,-thidiazol-5-ylurea (thidiazuron; Dropp; SN49537; TDZ) on metabolic changes in apple buds during dormancy break were determined. The data showed that thidiazuron has the capacity to release lateral buds from dormancy. Decreasing degree of bud break and bud growth with thidiazuron treatment occurred in a basipetal direction, suggesting a gradient of increasingly deep rest from shoot apex to base. The breaking of dormancy by thidiazuron is correlated with increase in DNA, RNA, protein, 1-aminocyclopropane-1-carboxylic acid (ACC), 1-(malonylamino) cyclopropane-1-carboxylic acid (MACC), S-adenosylmethionine (SAM) as well as with greater polyamine formation. Polyamine and ethylene biosynthesis did not seem to be competing for SAM, their common substrate, during bud break and bud development. The release of dormancy in apple bud by thidiazuron was inhibited by cordycepine, 5-fluorouracil, 6-methylpurine and cycloheximide. Inhibition of bud break and bud growth also resulted from treatment with α-difluoromethylarginine (DFMA) and α-difluoromethylornithine (DFMO). DFMO was more inhibitory than DFMA.
Removal of pesticide residue from Brussels sprouts by hydrostatic pressure

Abstract Food safety concerning polluted products has been of considerable interest in recent years. In our previous study, a pressurization technique was applied to cherry tomatoes laced with pesticides, and found that hydrostatic pressure treatment (HPT) reduces the amount of pesticides in samples. The objective of this study is to investigate whether HPT will affect Brussels sprouts, which have a rougher surface than cherry tomatoes. Samples were treated at several pressures (0.1–400 MPa) and at two temperatures (5 or 25 °C) for 30 min. Pesticide removed from samples accumulated in the surrounding water. Moreover, HPT was performed with ethanol solution as the surrounding medium, resulting in complete pesticide removal at comparatively low pressure. Under these conditions, visual changes did not occur, toxic intermediates from the pesticide were not detected, and nutrients from the samples were not found in the surrounding medium. Industrial relevance This article demonstrates that HPT with 10% ethanol solution is a potentially safe and harmless washing technology. It can remove pollutants from Brussels sprouts, which can then be collected from the surrounding medium, without breaking down the pollutant into more toxic materials. We believe that this washing process will be of interest to those involved with food safety, and may eventually be used for food safety during food production.
Pastures research in the Peruvian Amazon

There are few places on earth hotter than an Amazonian pasture at midday. With the canopy of the rainforest trees removed, the sun beats down relentlessly on unbroken fields of grass and weedy shrubs, baking plants, animals, and anthropologist alike. The forest is cool by comparison. Yet in pastures is where I found myself repeatedly while studying the role of cattle in the agricultural production systems of colonist farmers in the Peruvian Amazon.
Hydrotalcite-like structures as molecular containers for preparation of microporous carbons

Abstract Microporous carbons have been prepared by thermal treatment of poly (4-styrenesulfonate) derivative of MgAl hydrotalcites and subsequently the carbons extracted from the matrix. The interlayer carbonization process and the characteristics of the carbonaceous materials were studied by X-ray diffraction, inverse gas chromatography at infinite dilution (IGC), diffuse reflectance infrared spectroscopy (DRIFT), differential thermal analysis (DTA) and nitrogen and methane adsorption measurements. The structural and surface properties of the template carbons were compared to carbon prepared from the same organic precursor using a conventional carbonization method. It was found that carbonization between the layers of hydrotalcite leads to a formation of highly microporous carbons without additional activation processes.
Austauschmessungen mit 36Cl am [PCl4]+‐ und [PCl6]−‐lon

In Acetonitril wurde der Isotopenaustausch zwischen den Verbindungen [PCl4][PF6], [PCl4]F, [PCl4][PCl6] und radioaktiv am Chlor indiziertem [(C2H5)4N]Cl verfolgt. Es wird gezeigt, das die Stabilitat des [PCl4]+-Komplexes groser ist als die des [PCl6]−-Komplexes. Das Ergebnis steht im Einklang mit dem Verhalten dieser Komplexe bei der Fluorierung durch (AsF31). Die Austauschreaktion am [PCl4]+-Ion verlauft nach dem Gesetz 2. Ordnung mit gut mesbarer Geschwindigkeit (Halbwertszeiten 1–19 Minuten bei Konzentrationen von 0,3 bis 0,01 normal). Die Austauschhalbwertszeiten fur das [PCl6]−-Ion sind bei entsprechenden Konzentrationen kleiner als 0,6 sec. Die Bindungsverhaltnisse im [PCl4]+- und [PCl6]−-Ion werden diskutiert. Die Verbindung [(C2H5)4N][PCl6] ist in Acetonitrillosung nicht bestandig und zerfallt in Tetraathylammoniumchlorid und Phosphor(V)-chlorid.
Chemical and ultrastructural relationships between alfalfa leaf chloroplasts and bloat

Abstract Total and soluble leaf chloroplast protein levels were directly related to severity of bloat in cattle and sheep. The highest correlation was found between Fraction I chloroplast protein and bloat. Chlorophyll to protein ratios demonstrated a preferential synthesis of protein in chloroplasts during high-bloat stages. Progressing from non- to high-bloat-provoking forage, the percentage of soluble protein localized in chloroplasts increased from 45 to 77 per cent. Chloroplast lipids were inversely related to bloat. The percentages of total lipids in the chloroplasts suggest that preferential synthesis of chloroplast lipids occurs in non-bloat forage. Progressing from non- to high-bloat forage, the percentage of total leaf lipids localized in chloroplasts decreased from 71 to 27 per cent. Electron micrographs showed numerous large osmiophilic lipid granules in non-bloat chloroplasts. The number and size of the granules were highly correlated with changes in chloroplast lipids and bloat. Chloroplast fragments containing osmiophilic granules, starch grains and grana lamellae were observed in bolus juice and rumen fluid. Lamellae and osmiophilic granules were the only identifiable plant components found in rumen foam, while the chloroplast stroma was dispersed. These results strongly suggest that a stable foam is produced by an imbalance of protein and lipid chloroplast components which are specifically located within the stroma.
Hepatocellular Dysfunction after Severe Hypotension in the Absence of Blood Loss Is Associated with the Increased IL-6 and PGE2

Abstract Although hepatocellular dysfunction occurs following trauma and hemorrhagic shock, whether severe hypotension even in the absence of blood loss depresses hepatocellular function remains unknown. The aim of this study, therefore, was to determine whether chemically induced severe hypotension causes hepatocellular dysfunction and, if so, whether IL-6 and PGE 2 are associated with this dysfunction. To study this, hypotension was induced in adult male rats by intravenous infusion of a high dosage of ATP–MgCl 2 solution (3.2 ± 0.45 μmol/min/kg body wt) for 60 min. Blood pressure decreased from 108 ± 6 mm Hg to an average of 43 mm Hg during the infusion period and returned to normal levels immediately after the completion of ATP–MgCl 2 infusion. At 0 and 4 h after hypotension, hepatocellular function [i.e., maximum velocity of indocyanine green clearance ( V max ) and its efficiency ( K m )] was measured using a fiberoptic catheter and in vivo hemoreflectometer. Cardiac output was determined by dye dilution. Microvascular blood flow was assessed by laser Doppler flowmetry. Plasma levels of PGE 2 and IL-6 were measured by radioimmunoassay and bioassay, respectively. The results indicate that severe hypotension in the absence of any blood loss depresses hepatocellular function (i.e., decreased V max and K m ) despite stable cardiac output and hepatic perfusion at 0 and 4 h after the completion of hypotension. Moreover, severe hypotension resulted in significantly increased plasma levels of PGE 2 (only at 0 h) and IL-6. Thus, chemically induced severe hypotension in the absence of any blood loss, which does not significantly reduce cardiac output and hepatic perfusion, depresses hepatocellular function and upregulates IL-6 and PGE 2 production.