7,537 research outputs found

    General recursive solution for one dimensional quantum potentials: a simple tool for applied physics

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    A revision of the recursive method proposed by S.A. Shakir [Am. J.Phys. \textbf{52}, 845 (1984)] to solve bound eigenvalues of the Schr\"odinger equation is presented. Equations are further simplified and generalized for computing wave functions of any given one-dimensional potential, providing accurate solutions not only for bound states but also for scattering and resonant states, as demonstrated here for a few examples.Comment: Final version to appear in the Brazilian Magazine of Physics Teaching (http://www.sbfisica.org.br/noticias/publicacoes.shtml

    Assessment, technology and democratic education in the age of data

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    This paper contends that powerful techniques to manipulate data, enabled by technological and economic developments, can be easily co-opted to serve the restrictive frameworks of hyper-controlling, managerial accountability that characterise current cultures of summative assessment in education. In response to these challenges, research is urgently needed to increase our understanding of the impact that assessments have on individuals and society. The paper concludes that social research ought to contribute to the identification of responses – educational, technological and political – that can minimise inequalities and potential abuses through the encouragement of data literacy across society

    The concept of informal care: Ambiguities and controversies on its scientific and political uses

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    Starting from an analysis of the scientific and political uses of the concept of informal care, this paper raises questions and launches the debate on the causes and effects of its uses. Recognizing the diversity and the contradictions found across the use of the term, it explains how its predominant use in Europe can be problematic. First, although it is widely recognized that care is provided primarily by women, this gender dimension is not emphasized in a concept that obscures the sexual division. Second, it does not render explicit that informal care is work, despite being unpaid. Third, the allusion to informality is likely to generate confusion with informal employment of care workers. Finally, studies often focus exclusively on care provided by family members, without distinguishing the spaces in which the work takes place and the social relationships it involves, namely the family or community. In Europe, where documents from (non)governmental organizations focus mainly on long-term care related to demographic aging, it is the care crisis of formal care provision systems, faced with financial fragility, reduction in funds and insufficient supply to meet the demand, that brings informal care to the political and scientific agendas. This paper argues that it is necessary to define conceptual boundaries that allow international studies on the dimension and value of this care work to be compared. It also advocates the importance of making visible that this is work, unpaid and female-dominated, since this view supports action guidelines more focused on social transformation and empowerment.info:eu-repo/semantics/publishedVersio

    Modelling the live-electronics in electroacoustic music using particle systems

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    Developing the live-electronics for a contemporary electroacoustic piece is a complex process that normally involves the transfer of artistic and aesthetic concepts between the composer and the musical assistant. Translating in technical terms the musical, artistic and aesthetic concepts by means of algorithms and mathematical parameters is seldom an easy and straightforward task. The use of a particle system to describe the dynamics and characteristics of compositional parameters can reveal an effective way for achieving a significant relationship between compositional aspects and their technical implementation. This paper describes a method for creating and modelling a particle system based on compositional parameters and how to map those parameters into digital audio processes. An implementation of this method is described, as well as the use of such a method for the development of the work O Farfalhar das Folhas (The rustling of leaves) (2010), for one flutist, one clarinetist, violin, violoncello, piano and live-electronics, by Flo Menezes.info:eu-repo/semantics/publishedVersio

    Biomechanically tunable nano-silica/p-hema structural hydrogels for bone scaffolding

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    Innovative tissue engineering biomimetic hydrogels based on hydrophilic polymers have been investigated for their physical and mechanical properties. 5% to 25% by volume loading PHEMA-nanosilica glassy hybrid samples were equilibrated at 37◦C in aqueous physiological isotonic and hypotonic saline solutions (0.15 and 0.05 M NaCl) simulating two limiting possible compositions of physiological extracellular fluids. The glassy and hydrated hybrid materials were characterized by both dynamo-mechanical properties and equilibrium absorptions in the two physiological-like aqueous solutions. The mechanical and morphological modifications occurring in the samples have been described. The 5% volume nanosilica loading hybrid nanocomposite composition showed mechanical characteristics in the dry and hydrated states that were comparable to those of cortical bone and articular cartilage, respectively, and then chosen for further sorption kinetics characterization. Sorption and swelling kinetics were monitored up to equilibrium. Changes in water activities and osmotic pressures in the water-hybrid systems equilibrated at the two limiting solute molarities of the physiological solutions have been related to the observed anomalous sorption modes using the Flory-Huggins interaction parameter approach. The bulk modulus of the dry and glassy PHEMA-5% nanosilica hybrid at 37◦C has been observed to be comparable with the values of the osmotic pressures generated from the sorption of isotonic and hypotonic solutions. The anomalous sorption modes and swelling rates are coherent with the difference between osmotic swelling pressures and hybrid glassy nano-composite bulk modulus: the lower the differences the higher the swelling rate and equilibrium solution uptakes. Bone tissue engineering benefits of the use of tuneable biomimetic scaffold biomaterials that can be “designed” to act as biocompatible and biomechanically active hybrid interfaces are discussed

    Sentinel node biopsy and radical lymph node dissection for advanced melanoma in the elderly

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    Articolo presente su PubMed Central. Sourcerecord Id Scopus: 28558 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3194399/ Background.The majority of indications for surgery in melanoma are for the treatment of primary tumor and lymph node metastases. During the last decade, the Sentinel Node Biopsy (SNB), from a research procedure, has become standard of care in most institutions. SNB is normally considered for patients with melanoma > 1 mm and generally about 20% are positive; however, the risk of a positive SNB in a melanoma < 1 mm is still 5%. Usually when SNB is positive a complete lymphadenectomy is performed. Materials and methods.In the period 2004-2009, 18 elderly patients (median age 68 years) affected by cutaneous melanoma (mean Breslow’s thickness = 3.77 mm), after SNB histologically confirmed regional lymph node involvement, underwent complete lymph node dissection (CLND). We treated 11 of them with groin dissection, in 3 cases bilateral; 4 patients underwent axillar dissection, in one case bilateral; 2 patients underwent neck dissection and another patient underwent groin-axillar dissection. We treated bilateral groin involvement with laparoscopic access for dissection of lumbar-aortic, iliac and obturator lymph nodes. Results.Disagreeing with literature, 12/18 (67%) of these patients had positive lymph nodes, a high percentage if compared with younger patients’ data. Currently the average follow-up is 25 months. In our sample CLND has a crucial prognostic role (16% vs 41% of deceased in CLND – and CLND + patients respectively). Conclusions.Elderly melanoma patients are characterized by a higher tumor stage and, in patients with nodal metastases, the prognosis is independently affected by older age. In case of positive SNB the CLND plays a notable prognostic role and a presumable therapeutic role

    TEM in the treatment of recurrent rectal cancer in the elderly

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    Articolo presente su PubMed Central. Surcerecord id Scopus 28558 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3194378/ Introduction.Transanal endoscopic microsurgery is a useful technique of minimally invasive surgery that allows the realization of complex interventions, from transanal excisions to full thickness resections with anastomotic reconstructions. TEM can have a diagnostic and therapeutic value in the elderly for the treatment of primary rectal cancer as well as for recurrences. Materials and methods.During the period between January 2002 and December 2009 six patients, average age of 66 years, four men and two women, with early diagnosed rectal cancer recurrence were selected to undergo this palliative surgical procedure. 3 men and 1 woman underwent "ultra-low anterior resection”, followed by chemo / radio therapy (T3N1M0); in one woman a TEM (T1NxM0) and in one old man the local escission was performed after neoadiuvant chemo/radio therapy (T2NxM0). The selection of the patients was made by: rigid sigmoidoscope, transrectal us, colonoscopy, abdominal us to rule out liver metastases, CT and MRI abdomen and pelvis with and without contrast agents, PET CT. In all patients the lesions were superficial, smaller than 2 cm and located at the posterior wall of the rectum. Results.Follow-up was approximately 12-28 months; the pathologic staging confirmed the complete excision of recurrences. Patients were then referred for more complementary therapies. Only one patient presented a retro rectal abscess treated with conservative techniques, too. Conclusions.The alternative to conservative surgery is an abdomino-perineal resection sec. Miles, but also this really invasive procedure can be considered palliative in the most part of recurrences. So, based on equal oncological results, the reduction of surgical trauma and preservation of anatomical integrity are really important goals

    Laparoscopy in bilio-pancreatic surgery in elderly

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    Articolo presente su PubMed Central. Sourcerecord id Scopus 28558 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3194374/ Background.More minimally invasive techniques are currently available for the surgical oncologist in the optimal staging of biliopancreatic cancer. With the increased age of population we can see an increase of age-related diseases, such a cardiovascular disease, hypertension, arthritis and other malignancies. With the development of endoscopy, laparoscopy, ultrasonography and biopsy equipment, more minimally invasive techniques are currently available for the surgical oncologist to provide a better optimal diagnosis and strategy, followed by an appropriate surgical treatment of biliopancreatic cancer. Improvement in the diagnostic and surgical care of elderly cancer patients will have a final impact on disease and overall survival rates of the different types of cancer treatment. Materials and methods.We retrospectively reviewed the records of patients between January 2001 and December 2008 who had either a mass in the biliopancreatic area classified as clinically resectable. Tumours were considered to be resectable when there was no evidence of distant extra pancreatic disease or involvement of lymphnodes outside the classic margins of resections. Occlusion or encasement of the superior mesenteric artery or vein, celiac artery or portal vein were used as a criteria for unresectability. Twenty-eight patients over 65 and under 75 years (middle age 69) with primary biliopancreatic cancer were submitted to operations for potentially operative resection. In all cases staging laparoscopy was performed just prior to planned open exploration and resection. Results.Twenty seven patients underwent laparoscopy exploration for potential resection. Two of five patients (40%) with distal cholangiocarcinoma survived at 5 years after DCP. Eighteen patients (66.6%) had unresectable disease identified at laparoscopy and fourteen were able to convert to laparotomy palliative surgery while for the others laparoscopy spared an unnecessary laparotomy. In four patients it was possible to perform a laparoscopy palliative surgery. Conclusions.Laparoscopy may have a role in the staging of patients with biliopancreatic malignancies, in particular, for reduction of unnecessary exploratory laparotomy. Moreover, even in old age, duodenocephalopancreasectomy, properly planned and executed, resulted in reduction of operative mortality and morbility and a clear long-term survival
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