92 research outputs found

    The Electrostatic Interaction of Charged, Dust-Particle Pairs in Plasmas

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    We report the results of a study of the electrostatic interaction between negatively charged particles in a plasma. The goal of the study was to investigate the possibility of an attractive interaction which would make possible the formation of “molecules” of particles. For all approximations relating the positive ion density to the local electrostatic potential that we examined, we find that the interaction is repulsive for all particle separations

    Treatment Options in Cushing’s Disease

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    Endogenous Cushing’s syndrome is a grave disease that requires a multidisciplinary and individualized treatment approach for each patient. Approximately 80% of all patients harbour a corticotroph pituitary adenoma (Cushing’s disease) with excessive secretion of adrenocorticotropin-hormone (ACTH) and, consecutively, cortisol. The goals of treatment include normalization of hormone excess, long-term disease control and the reversal of comorbidities caused by the underlying pathology. The treatment of choice is neurosurgical tumour removal of the pituitary adenoma. Second-line treatments include medical therapy, bilateral adrenalectomy and radiation therapy. Drug treatment modalities target at the hypothalamic/pituitary level, the adrenal gland and at the glucocorticoid receptor level and are commonly used in patients in whom surgery has failed. Bilateral adrenalectomy is the second-line treatment for persistent hypercortisolism that offers immediate control of hypercortisolism. However, this treatment option requires a careful individualized evaluation, since it has the disadvantage of permanent hypoadrenalism which requires lifelong glucocorticoid and mineralocorticoid replacement therapy and bears the risk of developing Nelson’s syndrome. Although there are some very promising medical therapy options it clearly remains a second-line treatment option. However, there are numerous circumstances where medical management of CD is indicated. Medical therapy is frequently used in cases with severe hypercortisolism before surgery in order to control the metabolic effects and help reduce the anestesiological risk. Additionally, it can help to bridge the time gap until radiotherapy takes effect. The aim of this review is to analyze and present current treatment options in Cushing’s disease

    On the rise and fall of oceanic islands:Towards a global theory following the pioneering studies of Charles Darwin and James Dwight Dana

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    The careers of Charles Darwin (1809–1882) and James Dwight Dana (1813–1895) are intimately linked to circumnavigations of the globe with the British mapping expedition on the H.M.S. Beagle (1831–1836) under Captain Robert FitzRoy and the United States Exploring Expedition (1838–1842) under Lieutenant Charles Wilkes. The former expedition mainly surveyed coastal South America, but also visited many volcanic islands in the Atlantic, Pacific, and Indian oceans. The latter expedition followed a similar path through the Atlantic, but devoted more time to Pacific Ocean islands. Remembered more today for his visit to the Galapagos Islands and its subsequent impact on understanding the mechanisms of biological evolution, Darwin was motivated early on during his stopover in the Cape Verde Islands to compile studies on the geology of volcanic islands. Better known for his theory of atoll development from the subsidence of volcanic islands stimulated by his visit to the Keeling Islands and published in 1842, Darwin also wrote a related volume published in 1844 with an equally strong emphasis on island uplift. Dana was influenced by Darwin's theory of atoll development, and published his own independent observations on coral reefs and island subsidence in 1843, 1849, and 1853. The work of both geologists matured from primary observations using inductive logic during fieldwork (i.g. unconformable position of limestone on and between basalt flows as an indicator of paleo-sea level) to the advancement of broader theories regarding the behavior of the Earth's oceanic crust. Notably, Dana recognized age differences among islands in Pacific archipelagos and was strongly influenced by the orientations of those island groups. The classic Hawaiian model that features a linear string of progressively older and subsiding islands does not apply easily to many other island groups such as the Galapagos, Azores, Canary, and Cape Verde islands. Geologists and coastal geomorphologists increasingly find that the original observations on island uplift covered in Darwin's, 1844 treatment provide an alternative pathway to understanding the complexities of island histories in oceanic settings. Original work by Darwin and Dana also led to ongoing studies on the trans-oceanic migrations of marine organisms, such as barnacles, corals and non-attached coralline red algae represented by rhodoliths. This work gives added importance to oceanic islands as way stations in the dispersal of biotas over time.</p

    What Darwin did not see : Pleistocene fossil assemblages on a highenergy coast at Ponta das Bicudas, Santiago, Cape Verde Islands

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    Two distinct Pleistocene assemblages from SE Santiago Island are comparable to modern analogues elsewhere in the Cape Verde Islands. A low-diversity Siderastrea radians assemblage lived atop basalt knobs surrounded by sand on a slope below a cliff. A Millepora alcicornis–Megabalanus azoricus assemblage occupied the cliff. The latter was a typical rocky-shore assemblage from a high-energy setting belowthe tidal zone.Bioerosion structures in basalt produced by Circolites kotoncensis and Gastrochaenolites isp. also occur there. Despite extensive studies on local limestone deposits in 1832 and 1836, lack of exposure prevented Darwin from seeing these fossils.Funding for fieldwork on Santiago Island in June 2011 was provided under grant CGL2010-15372-BTE from the Spanish Ministry of Science and Innovation to project leader Eduardo Mayoral (University of Huelva). Financial support to A. Santos came from the Spanish Ministry of Science and Technology (Juan de la Cierva subprogram, Ref: JCI-2008-2431). Additional support by the Junta de Andalucia (Spanish government) to the Research Group RNM276 is also acknowledged. Partial funding to J. Ledesma-Vazquez on this project came from the Programma Integral de Fortalecimiento Institucional 2010. We thank Christopher K. Pham, Department of Oceanography and Fisheries, University of the Azores, Portugal, for help with identification of the fossil barnacles and Ricardo Ramalho, Institut fur Geophysik, Westphalishe-Wilhelms Universitat, Germany, for discussions about bioerosion by sea urchins on basalt surfaces

    Effects of supervised exercise on cancer-related fatigue in breast cancer survivors: a systematic review and meta-analysis

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    Background: Cancer-related fatigue (CRF) is the most common and distressing symptom in breast cancer survivors. Approximately 40% to 80% of cancer patients undergoing active treatment suffer from CRF. Exercise improves overall quality of life and CRF; however, the specific effects of the training modalities are not well understood.Methods: This study aimed to determine the pooled effects of supervised exercise interventions on CRF in breast cancer survivors. We searched PubMed/MEDLINE, EMBASE, Scopus, CENTRAL and CINAHL databases between December 2013 and January 2014 without language restrictions. Risk of bias and methodological quality were evaluated using the PEDro score. Pooled effects were calculated with a random-effects model according to the DerSimonian and Laird method. Heterogeneity was evaluated with the I2 test.Results: Nine high-quality studies (n = 1156) were finally included. Supervised aerobic exercise was statistically more effective than conventional care in improving CRF among breast cancer survivors (SMD = −0.51, 95%CI −0.81 to −0.21), with high statistical heterogeneity (P = 0.001; I2 = 75%). Similar effects were found for resistance training on CRF (SMD = −0.41, 95%CI −0.76 to −0.05; P = 0.02; I2 = 64%). Meta-regression analysis revealed that exercise volume parameters are closely related with the effect estimates on CRF. Egger’s test suggested moderate evidence of publication bias (P = 0.04).Conclusions: Supervised exercise reduces CRF and must be implemented in breast cancer rehabilitation settings. High-volume exercises are safe and effective in improving CRF and overall quality of life in women with breast cancer. Further research is encouraged.The authors would like to acknowledge Universidad Santo Tomás, Bogotá for the financial support to the GICAEDS Group (Project: Práctica del autoexamen de seno y los conocimientos, factores de riesgo y estilos de vida relacionados al cáncer de mama en mujeres jóvenes de la USTA – Number: 4110060001-008)

    Defining the industrial and engineering management professional profile: a longitudinal study based on job advertisements

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    The engineering professional profiles have been discussed by several branches of the engineering field. On the one hand, this discussion helps to understand the professional practice and contributes to the specification of the competences that are suitable for each function and company culture. On the other hand, it is an essential starting point for the definition of curricula in engineering schools. Thus, this study aims to characterize, in an innovative way based on job advertisements, the demand for competences and areas of practice for Industrial Engineering and Management contributing for the definition of a professional profile. This characterization is based on the analysis of 1391 job advertisements, collected during seven years from a Portuguese newspaper. The data analysis takes into account the job description in which two categories were considered: areas of professional practice (e.g. project management) and transversal competences (e.g. teamwork). Considering the total number of job advertisements, it was possible to identify 1,962 cumulative references for 11 professional practice areas and 5,261 cumulative references for transversal competences. The contribution of this study lies on the identification of the main areas of practice and the main transversal competences demanded by employers.This work was partially funded by COMPETE-POCI-01-0145-FEDER-007043 and FCT-UID-CEC-00319-2013

    Design of the Physical exercise during Adjuvant Chemotherapy Effectiveness Study (PACES):A randomized controlled trial to evaluate effectiveness and cost-effectiveness of physical exercise in improving physical fitness and reducing fatigue

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    <p>Abstract</p> <p>Background</p> <p>Cancer chemotherapy is frequently associated with a decline in general physical condition, exercise tolerance, and muscle strength and with an increase in fatigue. While accumulating evidence suggests that physical activity and exercise interventions during chemotherapy treatment may contribute to maintaining cardiorespiratory fitness and strength, the results of studies conducted to date have not been consistent. Additional research is needed to determine the optimal intensity of exercise training programs in general and in particular the relative effectiveness of supervised, outpatient (hospital- or physical therapy practice-based) versus home-based programs.</p> <p>Methods</p> <p>This multicenter, prospective, randomized trial will evaluate the effectiveness of a low to moderate intensity, home-based, self-management physical activity program, and a high intensity, structured, supervised exercise program, in maintaining or enhancing physical fitness (cardiorespiratory fitness and muscle strength), in minimizing fatigue and in enhancing the health-related quality of life (HRQoL). Patients receiving adjuvant chemotherapy for breast or colon cancer (n = 360) are being recruited from twelve hospitals in the Netherlands, and randomly allocated to one of the two treatment groups or to a 'usual care' control group. Performance-based and self-reported outcomes are assessed at baseline, at the end of chemotherapy and at six month follow-up.</p> <p>Discussion</p> <p>This large, multicenter, randomized clinical trial will provide additional empirical evidence regarding the effectiveness of physical exercise during adjuvant chemotherapy in enhancing physical fitness, minimizing fatigue, and maintaining or enhancing patients' quality of life. If demonstrated to be effective, exercise intervention programs will be a welcome addition to the standard program of care offered to patients with cancer receiving chemotherapy.</p> <p>Trial registration</p> <p>This study is registered at the Netherlands Trial Register (NTR 2159)</p
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