639 research outputs found

    Beyond and beneath the hierarchical market economy: global production and working-class conflict in Argentina's automobile industry

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    This paper argues that the hierarchical market economy (HME) category does not provide an adequate starting point for addressing capitalist diversity in Latin America. Building from a critical perspective on the global commodity chain (GCC) and global production network (GPN) approaches, it instead considers the impact of firms’ transnational relations and the often neglected role of working-class struggles. It will argue that capitalist diversity can only be understood at the nexus of these ostensibly global and local phenomena; and by specifying the strategic decisions taken by firms in Argentina’s automobile industry, it will account for the failure of that sector. Finally, it examines the role of working-class struggles in the industry in CΓ³rdoba, Argentina, arguing that these were vital in shaping the specific and unstable form of capitalist diversity in Argentina, as well as potential alternatives to it

    Water aerobics II: maternal body composition and perinatal outcomes after a program for low risk pregnant women

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    <p>Abstract</p> <p>Background</p> <p>To evaluate the effectiveness and safety of water aerobics during pregnancy.</p> <p>Methods</p> <p>A randomized controlled trial carried out in 71 low-risk sedentary pregnant women, randomly allocated to water aerobics or no physical exercise. Maternal body composition and perinatal outcomes were evaluated. For statistical analysis Chi-square, Fisher's or Student's t-tests were applied. Risk ratios and their 95% CI were estimated for main outcomes. Body composition was evaluated across time using MANOVA or Friedman multiple analysis.</p> <p>Results</p> <p>There were no significant differences between the groups regarding maternal weight gain, BMI or percentage of body fat during pregnancy. Incidence of preterm births (RR = 0.84; 95%CI:0.28–2.53), vaginal births (RR = 1.24; 95%CI:0.73–2.09), low birthweight (RR = 1.30; 95%CI:0.61–2.79) and adequate weight for gestational age (RR = 1.50; 95%CI:0.65–3.48) were also not significantly different between groups. There were no significant differences in systolic and diastolic blood pressure and heart rate between before and immediately after the water aerobics session.</p> <p>Conclusion</p> <p>Water aerobics for sedentary pregnant women proved to be safe and was not associated with any alteration in maternal body composition, type of delivery, preterm birth rate, neonatal well-being or weight.</p

    The effects of temperature and body mass on jump performance of the locust Locusta migratoria

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    Locusts jump by rapidly releasing energy from cuticular springs built into the hind femur that deform when the femur muscle contracts. This study is the first to examine the effect of temperature on jump energy at each life stage of any orthopteran. Ballistics and high-speed cinematography were used to quantify the energy, distance, and take-off angle of the jump at 15, 25, and 35Β°C in the locust Locusta migratoria. Allometric analysis across the five juvenile stages at 35Β°C reveals that jump distance (D; m) scales with body mass (M; g) according to the power equation D = 0.35M0.17Β±0.08 (95% CI), jump take-off angle (A; degrees) scales as A = 52.5M0.00Β±0.06, and jump energy (E; mJ per jump) scales as E = 1.91M1.14Β±0.09. Temperature has no significant effect on the exponent of these relationships, and only a modest effect on the elevation, with an overall Q10 of 1.08 for jump distance and 1.09 for jump energy. On average, adults jump 87% farther and with 74% more energy than predicted based on juvenile scaling data. The positive allometric scaling of jump distance and jump energy across the juvenile life stages is likely facilitated by the concomitant relative increase in the total length (Lf+t; mm) of the femur and tibia of the hind leg, Lf+t = 34.9M0.37Β±0.02. The weak temperature-dependence of jump performance can be traced to the maximum tension of the hind femur muscle and the energy storage capacity of the femur's cuticular springs. The disproportionately greater jump energy and jump distance of adults is associated with relatively longer (12%) legs and a relatively larger (11%) femur muscle cross-sectional area, which could allow more strain loading into the femur's cuticular springs. Augmented jump performance in volant adult locusts achieves the take-off velocity required to initiate flight.Edward P. Snelling, Christie L. Becker, Roger S. Seymou

    Fetal cardiotocography before and after water aerobics during pregnancy

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    <p>Abstract</p> <p>Objective</p> <p>To evaluate the effect of moderate aerobic physical activity in water on fetal cardiotocography patterns in sedentary pregnant women.</p> <p>Method</p> <p>In a non-randomized controlled trial, 133 previously sedentary pregnant women participated in multiple regular sessions of water aerobics in a heated swimming pool. Cardiotocography was performed for 20 minutes before and just after the oriented exercise. Cardiotocography patterns were analyzed pre- and post-exercise according to gestational age groups (24-27, 28-31, 32-35 and 36-40 weeks). Student's t and Wilcoxon, and McNemar tests were used, respectively, to analyze numerical and categorical variables.</p> <p>Results</p> <p>No significant variations were found between pre- and post-exercise values of fetal heart rate (FHR), number of fetal body movements (FM) or accelerations (A), FM/A ratio or the presence of decelerations. Variability in FHR was significantly higher following exercise only in pregnancies of 24-27 weeks.</p> <p>Conclusions</p> <p>Moderate physical activity in water was not associated with any significant alterations in fetal cardiotocography patterns, which suggests no adverse effect on the fetus.</p

    Long-term impacts of prenatal synthetic glucocorticoids exposure on functional brain correlates of cognitive monitoring in adolescence

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    The fetus is highly responsive to the level of glucocorticoids in the gestational environment. Perturbing glucocorticoids during fetal development could yield long-term consequences. Extending prior research about effects of prenatally exposed synthetic glucocorticoids (sGC) on brain structural development during childhood, we investigated functional brain correlates of cognitive conflict monitoring in term-born adolescents, who were prenatally exposed to sGC. Relative to the comparison group, behavioral response consistency (indexed by lower reaction time variability) and a brain correlate of conflict monitoring (the N2 event-related potential) were reduced in the sGC exposed group. Relatedly, source localization analyses showed that activations in the fronto-parietal network, most notably in the cingulate cortex and precuneus, were also attenuated in these adolescents. These regions are known to subserve conflict detection and response inhibition as well as top-down regulation of stress responses. Moreover, source activation in the anterior cingulate cortex correlated negatively with reaction time variability, whereas activation in the precuneus correlated positively with salivary cortisol reactivity to social stress in the sGC exposed group. Taken together, findings of this study indicate that prenatal exposure to sGC yields lasting impacts on the development of fronto-parietal brain functions during adolescence, affecting multiple facets of adaptive cognitive and behavioral control

    Stressor- and Corticotropin releasing Factor-induced Reinstatement and Active Stress-related Behavioral Responses are Augmented Following Long-access Cocaine Self-administration by Rats

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    Rationale Stressful events during periods of drug abstinence likely contribute to relapse in cocaine-dependent individuals. Excessive cocaine use may increase susceptibility to stressor-induced relapse through alterations in brain corticotropin-releasing factor (CRF) responsiveness. Objectives This study examined stressor- and CRF-induced cocaine seeking and other stress-related behaviors in rats with different histories of cocaine self-administration (SA). Materials and methods Rats self-administered cocaine under short-access (ShA; 2 h daily) or long-access (LgA; 6 h daily) conditions for 14 days or were provided access to saline and were tested for reinstatement by a stressor (electric footshock), cocaine or an icv injection of CRF and for behavioral responsiveness on the elevated plus maze, in a novel environment and in the light–dark box after a 14- to 17-day extinction/withdrawal period. Results LgA rats showed escalating patterns of cocaine SA and were more susceptible to reinstatement by cocaine, EFS, or icv CRF than ShA rats. Overall, cocaine SA increased activity in the center field of a novel environment, on the open arms of the elevated plus maze, and in the light compartment of a light–dark box. In most cases, the effects of cocaine SA were dependent on the pattern/amount of cocaine intake with statistically significant differences from saline self-administering controls only observed in LgA rats. Conclusions When examined after several weeks of extinction/ withdrawal, cocaine SA promotes a more active pattern of behavior during times of stress that is associated with a heightened susceptibility to stressor-induced cocaine-seeking behavior and may be the consequence of augmented CRF regulation of addiction-related neurocircuitry

    Conformal Quivers and Melting Molecules

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    Quiver quantum mechanics describes the low energy dynamics of a system of wrapped D-branes. It captures several aspects of single and multicentered BPS black hole geometries in four-dimensional N=2\mathcal{N} = 2 supergravity such as the presence of bound states and an exponential growth of microstates. The Coulomb branch of an Abelian three node quiver is obtained by integrating out the massive strings connecting the D-particles. It allows for a scaling regime corresponding to a deep AdS2_2 throat on the gravity side. In this scaling regime, the Coulomb branch is shown to be an SL(2,R)SL(2,\mathbb{R}) invariant multi-particle superconformal quantum mechanics. Finally, we integrate out the strings at finite temperature---rather than in their ground state---and show how the Coulomb branch `melts' into the Higgs branch at high enough temperatures. For scaling solutions the melting occurs for arbitrarily small temperatures, whereas bound states can be metastable and thus long lived. Throughout the paper, we discuss how far the analogy between the quiver model and the gravity picture, particularly within the AdS2_2 throat, can be taken.Comment: 49 pages, 16 figure

    Sperm design and variation in the New World blackbirds (Icteridae)

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    Post-copulatory sexual selection (PCSS) is thought to be one of the evolutionary forces responsible for the rapid and divergent evolution of sperm design. However, whereas in some taxa particular sperm traits are positively associated with PCSS, in other taxa, these relationships are negative, and the causes of these different patterns across taxa are poorly understood. In a comparative study using New World blackbirds (Icteridae), we tested whether sperm design was influenced by the level of PCSS and found significant positive associations with the level of PCSS for all sperm components but head length. Additionally, whereas the absolute length of sperm components increased, their variation declined with the intensity of PCSS, indicating stabilizing selection around an optimal sperm design. Given the diversity of, and strong selection on, sperm design, it seems likely that sperm phenotype may influence sperm velocity within species. However, in contrast to other recent studies of passerine birds, but consistent with several other studies, we found no significant link between sperm design and velocity, using four different species that vary both in sperm design and PCSS. Potential reasons for this discrepancy between studies are discussed

    Definitive and adjuvant radiotherapy for sinonasal squamous cell carcinomas: a single institutional experience

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    Background: The aim of this study was to evaluate the disease outcomes of patients treated with definitive and adjuvant radiotherapy for squamous cell carcinomas of the nasal cavity and paranasal sinuses in a single institution. Methods: Between 2007–2012 patients were retrospectively identified from electronic databases who had undergone surgery and adjuvant radiotherapy or definitive radiotherapy for sinonasal squamous cell carcinomas with curative intent. Results: Fourty three patients with sinonasal squamous cell carcinoma were identified (22 nasal cavity, 21 paranasal sinuses). 31/43 (72 %) had T3 or T4 disease; nodal stage was N0 in 38, N1 in 4, Na/b in 0 and N2c in 1 patient. Median age was 67 years (range 41–86). 18 (42 %) received definitive and 25 (58 %) adjuvant radiotherapy. Radiotherapy was delivered using either conventional radiotherapy (n = 39) or intensity modulated radiotherapy (n = 4). Elective neck radiotherapy was delivered to two patients. Chemotherapy was delivered to 6/43 (14 %) of patients. Two-year local control, regional control, distant metastases free survival, progression free survival, cause specific survival and overall survival were 81 %, 90 %, 95 %, 71 %, 84 % and 80 % respectively. There was no significant difference in outcome comparing patients who underwent surgery and adjuvant radiotherapy with patients receiving definitive radiotherapy (2 year locoregional disease free survival 75 % and 70 % respectively, p = 0.98). Pooly differentiated tumours were significantly associated with inferior disease outcomes. Local, regional, combined local and regional, and distant failure occurred in 7 (16 %), 3 (7 %), 1 (2 %) and 2 (5 %) of patients; all 3 regional recurrences were in patients with nasal cavity squamous cell carcinomas who had not undergone elective neck treatment. Conclusions: Definitive or adjuvant radiotherapy provides an effective treatment for sinonasal malignancies. The main pattern of failure remains local, suggesting the need for investigation of intensified local therapy. Whilst remaining uncommon, the cases of regional failure mean that the merits of elective lymph node treatment should be considered on an individual basis

    Determining the neurotransmitter concentration profile at active synapses

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    Establishing the temporal and concentration profiles of neurotransmitters during synaptic release is an essential step towards understanding the basic properties of inter-neuronal communication in the central nervous system. A variety of ingenious attempts has been made to gain insights into this process, but the general inaccessibility of central synapses, intrinsic limitations of the techniques used, and natural variety of different synaptic environments have hindered a comprehensive description of this fundamental phenomenon. Here, we describe a number of experimental and theoretical findings that has been instrumental for advancing our knowledge of various features of neurotransmitter release, as well as newly developed tools that could overcome some limits of traditional pharmacological approaches and bring new impetus to the description of the complex mechanisms of synaptic transmission
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