1,881 research outputs found

    Surgery corrects asynchrony of ribcage secondary to extra-thoracic tumor but leads to expiratory dysfunction during exercise

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    BACKGROUND: The effect of chest wall tumours on chest wall mechanics is uncertain even less is known about the effects of resection and reconstruction. Our aim is to study how chest wall mechanics are altered in chest wall sarcoma and to determine the effect of chest wall reconstruction on chest wall kinetics. CASE PRESENTATION: Using Optoelectronic Plethysmography (OEP), total and regional chest wall volumes were measured in a patient with unilateral extra-thoracic chest wall sarcoma, before and 5 months after resection and reconstruction, during quiet breathing and exercise using cycle ergometry. During quiet breathing the unilateral tumour was associated with reduced in motion of the lower rib cage and abdominal compartments on both sides of the chest as well as asynchronous motion of the contralateral lower rib cage. Surgery corrected these abnormalities in quiet breathing. But during exercise there was a reduction in the upper rib cage motion compared to pre-operative measures from 0.43+/−0.06 to 0.36 +/− 0.02 L postoperatively (p <0.05). This impairment was characterised by a significant increase in the end expiratory volume on the operated side of the chest 5 months after surgery by 6.5 +/− 0.6 and 5.7 +/− 0.7 % during 50 and 100 % exercise respectively (p <0.0001) a finding that was not replicated in the non-operated side. CONCLUSION: This physiological study demonstrates the negative effect of chest wall tumours on global chest wall mechanics during quiet breathing and exercise and shows that surgery reverses this abnormality, but only at rest

    Effect of maturity and harvest season on antioxidant activity, phenolic compounds and ascorbic acid of Morinda citrifolia L. (noni) grown in Mexico (with track change)

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    Antioxidant activity diphenylpicrylhydrazyl (DPPH), the ferric-reducing antioxidant power assay (FRAP), nitric oxide (NO)], total polyphenols, phenolic compounds and ascorbic acid of Morinda citrifolia L. fruits were investigated as a function of maturity and three seasons patterns in Mexico. Maturity was evaluated in early, middle, sub-mature and mature stages (1 to 4) according to color and firmness. Significant differences were observed in the antioxidant activities and chemical composition of the fruits at different maturity and seasons. During February-March and May- June, fruits from middle and mature stages exhibited the highest antioxidant activities and total polyphenol content compared to other stages, while in November, ripe fruits reached the greatest antioxidant efficacy, total phenolic and ascorbic acid contents. Total polyphenols and ascorbic acid reached the highest amounts during May-June, although antioxidant activities were moderate compared to greater values in February-March or November depending upon maturity. The ability of M. citrifolia fruits to inhibit NO production by LPSactivated RAW 264.7 cells was quite comparable to or higher than N-nitro-L-arginine methyl ester (LNAME). This work shows that season and maturity stages have a profound effect on the antioxidant capacity, phenols and ascorbic acid of M. Citrifolia fruits.Keywords: Morinda citrifolia, diphenylpicrylhydrazyl (DPPH) radical scavenging, maturity, seasons, total polyphenol and phenolics compounds, reducing power, ascorbic acid, scavenging nitric oxide.African Journal of Biotechnology Vol. 12(29), pp. 4630-463

    Leprosy Associated with Atypical Cutaneous Leishmaniasis in Nicaragua and Honduras

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    In Central America, few cases of leprosy have been reported, but the disease may be unrecognized. Diagnosis is based on clinical criteria and histology. Preliminary field work in Nicaragua and Honduras found patients, including many children, with skin lesions clinically suggestive of atypical cutaneous leishmaniasis or indeterminate leprosy. Histology could not distinguish these diseases although acid-fast organisms were visible in a few biopsies. Lesions healed after standard antimicrobial therapy for leprosy. In the present study, patients, family members, and other community members were skin-tested and provided nasal swabs and blood samples. Biopsies were taken from a subgroup of patients with clinical signs of infection. Two laboratories analyzed samples, using local in-house techniques. Mycobacterium leprae, Leishmania spp. and Leishmania infantum were detected using polymerase chain reactions. Mycobacterium leprae DNA was detected in blood samples and nasal swabs, including some cases where leprosy was not clinically suspected. Leishmania spp. were also detected in blood and nasal swabs. Most biopsies contained Leishmania DNA and coinfection of Leishmania spp. with M. leprae occurred in 33% of cases. Mycobacterium leprae DNA was also detected and sequenced from Nicaraguan and Honduran environmental samples. In conclusion, leprosy and leishmaniasis are present in both regions, and leprosy appears to be widespread. The nature of any relationship between these two pathogens and the epidemiology of these infections need to be elucidated

    Higgs decay with monophoton + MET signature from low scale supersymmetry breaking

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    We study the decay of a standard model-like Higgs boson into a gravitino and a neutralino, which subsequently decays promptly into another gravitino and a photon. Such a decay can be important in scenarios where the supersymmetry breaking scale is of the order of a few TeV, and in the region of low transverse momenta of the photon, it may provide the dominant contribution to the final state with a photon and two gravitinos. We estimate the relevant standard model backgrounds and the prospects for discovering this Higgs decay through a photon and missing transverse energy signal at the LHC in terms of a simplified model. We also give an explicit model with manifest, but spontaneously broken, supersymmetry in which the usual MSSM soft terms are promoted to supersymmetric operators involving a dynamical goldstino supermultiplet. This model can give rise to a SM-like CP-even neutral Higgs particle with a mass of 125 GeV, without requiring substantial radiative corrections, and with couplings sufficiently large for a signal discovery through the above mentioned Higgs decay channel with the upcoming data from the LHC.Comment: 28 pages, 5 figures, 4 tables; v2: updated to JHEP version, references adde

    NLSP Gluino Search at the Tevatron and early LHC

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    We investigate the collider phenomenology of gluino-bino co-annihilation scenario both at the Tevatron and 7 TeV LHC. This scenario can be realized, for example, in a class of realistic supersymmetric models with non-universal gaugino masses and t-b-\tau Yukawa unification. The NLSP gluino and LSP bino should be nearly degenerate in mass, so that the typical gluino search channels involving leptons or hard jets are not available. Consequently, the gluino can be lighter than various bounds on its mass from direct searches. We propose a new search for NLSP gluino involving multi-b final states, arising from the three-body decay \tilde{g}-> b\bar{b}\tilde{\chi}_1^0. We identify two realistic models with gluino mass of around 300 GeV for which the three-body decay is dominant, and show that a 4.5 \sigma observation sensitivity can be achieved at the Tevatron with an integrated luminosity of 10 fb^{-1}. For the 7 TeV LHC with 50 pb^{-1} of integrated luminosity, the number of signal events for the two models is O(10), to be compared with negligible SM background event.Comment: 14 pages, 4 figures and 3 tables, minor modifications made and accepted for publication in JHE

    Engaging with community researchers for exposure science: lessons learned from a pesticide biomonitoring study

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    A major challenge in biomonitoring studies with members of the general public is ensuring their continued involvement throughout the necessary length of the research. The paper presents evidence on the use of community researchers, recruited from local study areas, as a mechanism for ensuring effective recruitment and retention of farmer and resident participants for a pesticides biomonitoring study. The evidence presented suggests that community researchers' abilities to build and sustain trusting relationships with participants enhanced the rigour of the study as a result of their on-the-ground responsiveness and flexibility resulting in data collection beyond targets expected

    Collider signatures of goldstini in gauge mediation

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    We investigate the collider signatures of the multiple goldstini scenario in the framework of gauge mediation. This class of models is characterized by a visible sector (e.g. the MSSM or any extension) coupled by gauge interactions to more than one SUSY breaking sector. The spectrum consists of a light gravitino LSP, behaving as a goldstino, and a number of neutral fermions (the pseudo-goldstini) with a mass between that of the LSP and that of the lightest particle of the observable sector (LOSP). We consider the two situations where the LOSP is either a gaugino-like neutralino or a stau and we assume only one pseudo-goldstino of a mass of O(100) GeV. The coupling of the LOSP to the pseudo-goldstino can be enhanced with respect to those of the gravitino giving rise to characteristic signatures. We show that the decay modes of the LOSP into a SM particle and a pseudo-goldstino can be significant. For both LOSP scenarios we analyze (pseudo)-goldstini production at colliders. Compared to standard gauge mediation the final state spectrum is softer and more structured.Comment: v2: analysis of the stau LOSP scenario added, sections rearranged, and Introduction and Conclusions rewritten to include the added scenario. Version to appear in JHE

    Individual rules for trail pattern formation in Argentine ants (Linepithema humile)

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    We studied the formation of trail patterns by Argentine ants exploring an empty arena. Using a novel imaging and analysis technique we estimated pheromone concentrations at all spatial positions in the experimental arena and at different times. Then we derived the response function of individual ants to pheromone concentrations by looking at correlations between concentrations and changes in speed or direction of the ants. Ants were found to turn in response to local pheromone concentrations, while their speed was largely unaffected by these concentrations. Ants did not integrate pheromone concentrations over time, with the concentration of pheromone in a 1 cm radius in front of the ant determining the turning angle. The response to pheromone was found to follow a Weber's Law, such that the difference between quantities of pheromone on the two sides of the ant divided by their sum determines the magnitude of the turning angle. This proportional response is in apparent contradiction with the well-established non-linear choice function used in the literature to model the results of binary bridge experiments in ant colonies (Deneubourg et al. 1990). However, agent based simulations implementing the Weber's Law response function led to the formation of trails and reproduced results reported in the literature. We show analytically that a sigmoidal response, analogous to that in the classical Deneubourg model for collective decision making, can be derived from the individual Weber-type response to pheromone concentrations that we have established in our experiments when directional noise around the preferred direction of movement of the ants is assumed.Comment: final version, 9 figures, submitted to Plos Computational Biology (accepted

    LHC Predictions from a Tevatron Anomaly in the Top Quark Forward-Backward Asymmetry

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    We examine the implications of the recent CDF measurement of the top-quark forward-backward asymmetry, focusing on a scenario with a new color octet vector boson at 1-3 TeV. We study several models, as well as a general effective field theory, and determine the parameter space which provides the best simultaneous fit to the CDF asymmetry, the Tevatron top pair production cross section, and the exclusion regions from LHC dijet resonance and contact interaction searches. Flavor constraints on these models are more subtle and less severe than the literature indicates. We find a large region of allowed parameter space at high axigluon mass and a smaller region at low mass; we match the latter to an SU(3)xSU(3)/SU(3) coset model with a heavy vector-like fermion. Our scenario produces discoverable effects at the LHC with only 1-2 inverse femtobarns of luminosity at 7-8 TeV. Lastly, we point out that a Tevatron measurement of the b-quark forward-backward asymmetry would be very helpful in characterizing the physics underlying the top-quark asymmetry.Comment: 35 pages, 10 figures, 4 table
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