6,244 research outputs found

    Matter Lagrangians Coupled with Connections

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    We shall here consider extended theories of gravitation in the metric-affine formalism with matter coupled directly to the connection. A sufficiently general procedure will be exhibited to solve the resulting field equation associated to the connection. As special cases one has the no-coupling case (which is standard in f(R) literature) as well as the cases already analyzed in ref.[1].Comment: Refs adde

    First Order Extended Gravity and the Dark Side of the Universe: the General Theory

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    General Relativity is not the definitive theory of Gravitation due to several shortcomings which are coming out both from theoretical and experimental viewpoints. At large scales (astrophysical and cosmological scales) the attempts to match it with the today observational data lead to invoke Dark Energy and Dark Matter as the bulk components of the cosmic fluid. Since no final evidence, at fundamental level, exists for such ingredients, it is clear that General Relativity presents shortcomings at infrared scales. On the other hand, the attempts to formulate theories more general than the Einstein one give rise to mathematical difficulties that need workarounds which, in turn, generate problems from the interpretative viewpoint. We present here a completely new approach to the mathematical objects in terms of which a theory of Gravitation may be written in a first-order `a la Palatini formalism, and introduce the concept of Dark Metric which could completely bypass the introduction of disturbing concepts as Dark Energy and Dark Matter.Comment: Proceedings of the Conference "The Invisible Universe" Paris, June 29-July 3, 2009 10 page

    Covariant Lagrangian Formulation of Chern-Simons and BF Theories

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    We investigate the covariant formulation of Chern-Simons theories in a general odd dimension which can be obtained by introducing a vacuum connection field as a reference. Field equations, Noether currents and superpotentials are computed so that results are easily compared with the well-known results in dimension 3. Finally we use this covariant formulation of Chern-Simons theories to investigate their relation with topological BF theories.Comment: 23 pages, refs. adde

    The anesthesiologist and end-of-life care

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    Purpose of review Anesthesiologists may face problematic situations when patients are close to death, in which clinical problems, decision-making processes, and ethical issues are often interconnected and dependent on each of them. The aim of this review is to assess the recent literature regarding the anesthesiological role for advanced cancer patients. Recent findings Palliative sedation in the dying patients, end-of-life problems in the ICU, and pain control in advanced cancer patients have been the subject of recent research. All these issues have shown that anesthesiologist would be expert in the field of pain and symptom control at the end of life. End-of-life care problems are common in ICU, and a decision-making process requires knowledge and management of patients’ wishes, past and projected future quality of life, severity and prognosis of illness, patients’ age, regarding withholding and withdrawing of futile treatments in anticipation of death, or relieving symptoms close to death. Summary Anesthesiologists should be competent in all aspects of terminal care, including the practical and ethical aspects of withdrawing different modalities of life-sustaining treatment and the use of sedatives, analgesics, and nonpharmacologic approaches to easing the suffering of the dying process. More research is needed to provide models which should be spread in the scientific community to afford this difficult task

    Combined oral prolonged-release oxycodone and naloxone in chronic pain management

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    Introduction: The use of opioids is associated with unwanted adverse effects, particularly opioid-induced constipation (OIC). The adverse effects of opioids on gastrointestinal function are mediated by the interaction with opioid receptors in the gastrointestinal tract. The most common drugs used for relieving OIC are laxatives, which do not address the opioid receptor-mediated bowel dysfunction and do not provide sufficient relief. Areas covered: This paper discusses the role of a combination of prolongedrelease formulation of oxycodone (OX) and naloxone (N) in the prevention and management of OIC, reporting efficacy and safety outcome of controlled studies. In a therapeutic area of great unmet need, the combination tablet of prolonged release of OX and N (PR OXN) could offer patients effective analgesia, while improving opioid-induced bowel dysfunction. Expert opinion: PR OXN offers a unique and specific mechanism to control OIC in patients receiving chronic opioid therapy. This combination has the potential advantage of preventing OIC, particularly in subgroups of population, like elderly or advanced cancer patients. This approach can decrease the use of laxatives and additional medications, which represent a burden for patients presenting comorbidities requiring multiple medication

    The long and winding road of non steroidal antinflammatory drugs and paracetamol in cancer pain management: A critical review

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    The aim of this review was to assess the value of NSAIDs and paracetamol in patients with cancer pain to update a previous review performed ten years ago on this topic. The approach was analytic and based on clinical considerations, rather than on raw evidence, which often does not provide useful information in clinical practice. Both published reports from an extensive search of electronic data bases were collected from January 2001 to December 2011. A free-text search method was used including the following words and their combination: “Anti-inflammatory drugs OR paracetamol OR acetaminophen” AND/OR “cancer pain”. Any randomized-controlled trial was considered. Thirteen reports fulfitted inclusion criteria in this systematic review. Randomized trials have been performed by using different modalities of intervention. Single drugs added on opioid therapy or during opioid substitution with opioids as rescue drugs through a patient controlled analgesia, were compared with placebo or between them. Five studies regarded paracetamol. Other four studies assessed the efficacy dipyrone, ketorolac, dexketoprofen, and subcutaneous ketoprofen in cancer pain management, mainly on top of an opioid regimen. The role of paracetamol and NSAIDs in the management of cancer pain still remains controversial. The papers published in this last decade were unable to answer the main questions. There is no proof that they should be used to start the treatment and how long they should be administered when opioid treatment is added on top. While paracetamol seems to be devoid of any benefit, particularly if given at usual clinical doses which should be less than 4 g/day, ketorolac seems to provide an additive analgesic effect even in patients receiving different doses of opioids. The main indication from the analysis of these data is that NSAIDs could be given in patients receiving opioids, evaluating their benefit and weight on opioid therapy in individual patients who have a favorable response to justify a prolonged use

    Medical treatment for inoperable malignant bowel obstruction: a qualitative systematic review

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    The use of symptomatic agents has greatly improved the medical treatment of advanced cancer patients with inoperable bowel obstruction. A systematic review of studies of the most popular drugs used in the medical management of inoperable malignant bowel obstruction was performed to assess the effectiveness of these treatments and provide some lines of evidence. Randomized trials that involved patients with a clinical diagnosis of intestinal obstruction due to advanced cancer treated with these drugs were reviewed. Five reports fulfilled inclusion criteria. Three studies compared octreotide (OC) and hyoscine butylbromide (HB), and two studies compared corticosteroids (CSs) and placebo. Globally, 52 patients received OC, 51 patients received HB, 37 patients received CSs, 15 patients received placebo, and 37 patients received both placebo and CSs. On the basis of these few data, the superiority of OC over HB in relieving gastrointestinal symptoms was evidenced in a total of 103 patients. The latter studies had samples more defined in terms of stage and inoperability, and had a shorter survival in comparison with studies of CSs (less than 61 days, most of them less than 20 days). Data on CSs are less convincing, due to the methodological weakness of existing studies. This review confirms the difficulties in conducting randomized controlled trials in this population

    US Food and Drug Administration's Risk Evaluation and Mitigation Strategy for Extended-Release and Long-Acting Opioids Pros and Cons, and a European Perspective

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    Prescriptions for opioid analgesics to manage moderate-to-severe chronic non-cancer pain have increased markedly over the last decade. An unintentional consequence of greater prescription opioid utilization has been the parallel increase in misuse, abuse and overdose, which are serious risks associated with all opioid analgesics. In response to disturbing rises in prescription opioid abuse, the US Food and Drug Administration (FDA) has proposed the implementation of aggressive Risk Evaluation and Mitigation Strategies (REMS). While REMS could dramatically change the development, release, marketing and prescription of extended-release opioids, questions remain on how these programmes may influence prescribing practices, patient safety and ultimately patient access to these agents. The extent of the availability and misuse of prescription opioids in Europe is difficult to assess from the data currently available, due in large part to the considerable differences in prescribing patterns and regulations between countries. Balancing the availability of prescription opioids for those patients who have pain, while discouraging illicit use, is a complex challenge and requires effective efforts on many levels, particularly in Europe where policies are quite different between countries
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