5,411 research outputs found

    Interaction ramps in a trapped Bose condensate

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    Non-adiabatic interaction ramps are considered for trapped Bose-Einstein condensates. The deviation from adiabaticity is characterized through the heating or residual energy produced during the ramp. We find that the dependence of the heat on the ramp time is very sensitive to the ramp protocol. We explain features of this dependence through a single-parameter effective description based on the dynamics of the condensate size.Comment: 4 pages, 3 figure

    Dipolar Bose-Einstein condensate of Stationary-Light Dark-state Polaritons

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    We put forward and discuss in detail a scheme to achieve Bose-Einstein condensation of stationary-light dark-state polaritons with dipolar interaction. To this end we have introduced a diamond-like coupling scheme in a vapor of Rydberg atoms under the frozen gas approximation. To determine the system's dynamics we employ normal modes and identify the dark-state polariton corresponding to one of the modes. We show that in contrast to atomic dipolar ultra-cold vapors dark-state polariton Bose-Einstein condensates proposed here can be stable for a negative dipolar interaction constant.Comment: 5 pages, 1 figur

    A History of the Oldham, South Dakota Socialist Hall from 1913 to 1970

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    There may be many reasons for the appearance of the Socialist Hall in Oldham, South Dakota. Certainly a primary factor for its construction was the controversial Socialist party that formed a local branch in the Oldham area in 1912. It may be of interest to note that the town of Oldham had an opera house operating prior to the Socialist Hal1 and after the new hal1 was constructed, both continued to provide the community with a wide variety of entertainment and community activities. Unfortunately, the lack of information and the limited time and space does not allow the first opera house to be included in this study. It should also be pointed out that the size of the community, its geographic location, and its accessibility to a major railway were also important factors relating to the need to maintain the Socialist Hall in Oldham, South Dakota. The hall is currently located on the grounds of Prairie Village, South Dakota and provides South Dakota State University\u27s Summer Repertory Theatre a place to perform summer plays. As a previous member of this company with a personal interest in local history, the writer felt motivated to undertake a detailed investigation of the history of the Oldham, South Dakota Socialist Hall. To develop this history, answers to the following questions were sought: (1) What factors were responsible for the construction of the Socialist Hall in Oldham, South Dakota? (a) What role did the local Socialist party play? (b) What other factors may have been influential to the construction of the Hall? (2) How was the physical design of the building related to the Hall\u27s adaptability to various activities? (a) How was the exterior constructed? (b) What were the physical properties of the interior that helped it to be utilized as a multipurpose Hal)? (c) How was the Socialist Hall managed? (3) What professional dramatic touring companies performed .in the Hall? (4) What professional variety touring companies performed at the Hall? (5) How was the Socialist Hall used to support amateur drama in the community? (6) What major rhetorical activities took place in the Hall? (a) What professional lecture agencies were active in the Hall? (b) How did the community utilize the Socialist Hall for political and community meeting? (7) What other community functions were held in the Socialist Hal)? (8) How well received were the aforementioned activities? (9) What led to the demise of the Socialist Hall? It is hoped that this study will inspire others to research similar areas so that a more complete understanding of the functional importance of the local opera houses and community halls can be provided. A study of this nature may also provide a better understanding of theatre and rhetorical activities in rural America

    The US current account deficit : how did it come about and what are the policy implications

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    One of the most remarkable characteristics of the world economy today is the enormous, ever worsening US balance of payments current account deficit, which reached a record level of 5.7 p.c. of GDP in 2004. This has given rise to concerns in academic and political circles regarding the sustainability of the current situation and the potential dangers for the global economy of a sudden, disorderly adjustment. The size of the US current account deficit is not only unprecedented in American post-war history, but it also seems to be exceptional from an international perspective. Moreover, the US deficit contrasts with a surplus in virtually every other region and the problem has consequently taken on a global dimension. The increase in the US current account deficit recorded in the nineties reflects an internal American shortfall in savings. Whereas the private savings-investment equilibrium was restored in 2002 and 2003, the same period saw a huge deficit in the public sector budget. The start of the new millennium brought notable changes in the way the US current account deficit was financed since investments by Asian public authorities in American government debt instruments largely took over the position previously occupied by European private foreign direct investments and investments in equities. It is sometimes put forward that the US, unlike other countries facing similar circumstances, is safeguarded from an attack on its currency because of its prominent role in the international financial system. According to an influential school of thought in economic literature, the current international system can even be seen as a “revived” Bretton Woods system. Indeed, a number of East-Asian countries, including China, use a fixed or quasi-fixed exchange rate against the dollar, which brings to mind an informal dollar standard. Although this set of circumstances has undoubtedly offered various regions in the world a number of mutual benefits during recent years, these exchange rate relations may nevertheless have caused some distortions in US spending, whereas Asian countries have to deal with a growing exchange rate risk on their official reserves. Different scenarios are conceivable to deal with the global imbalances. The results of model simulations show the huge effort required to significantly reduce the US current account deficit which highlights the scale of the problem, emphasising the need for simultaneous economic policy measures in the different economies involved. The concern over global imbalances and the development of exchange rates also feature prominently on the agenda of international forums such as the G7 or G20 meetings. In the statements issued at those meetings, the need for a common approach to tackle the global imbalances is given priority and the belief that excessive exchange rate volatility is not desirable is underlined.current account imbalances, United States current account, financial flows into the United States, international monetary system

    Pathways to Disability Income among Persons with Severe, Persistent Psychiatric Disorders

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    [Excerpt] Harsh skepticism pervades current public debate about who deserves public support and on what basis, particularly regarding the claims of individuals with disabling illness and injury. Heretofore, these claims were accepted, even reservedly, and the needs of such individuals were considered to be legitimate even when they were monitored closely. The Supplemental Security Income (SSI) and Social Security Disability Insurance (SSDI) programs and their recipients have been among the most visible and vulnerable targets of increased scrutiny and shrinking public beneficence. In 1997, congressional legislation redefined SSI eligibility for children, sparked largely by concerns that children have been deployed to engage in a type of public begging by acting crazy in order to secure benefits for their families. Maladaptive behaviors was removed from the mental disorder listings, and the Social Security Administration (SSA) estimates that 135,000 children will lose their benefits after review. In March 1996, Congress eliminated SSI, SSDI, Medicare, and Medicaid benefits for persons whose drug addiction or alcoholism is a prominent cause of disability, and as a result 141,000 recipients have been terminated. The SSA also was ordered to begin another sweeping review of all recipients of disability income. SSA officials reportedly expect this process to produce a termination rate of 14 percent, resulting in an estimated 196,000 additional individuals who would cease to receive SSI and SSDI

    Sagnac interferometry based on ultra-slow polaritons in cold atomic vapors

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    The advantages of light and matter-wave Sagnac interferometers -- large area on one hand and high rotational sensitivity per unit area on the other -- can be combined utilizing ultra-slow light in cold atomic gases. While a group-velocity reduction alone does not affect the Sagnac phase shift, the associated momentum transfer from light to atoms generates a coherent matter-wave component which gives rise to a substantially enhanced rotational signal. It is shown that matter-wave sensitivity in a large-area interferometer can be achieved if an optically dense vapor at sub-recoil temperatures is used. Already a noticeable enhancement of the Sagnac phase shift is possible however with much less cooling requirements.Comment: 4 pages, 3 figure

    Experimental infection of the pig with Mycobacterium ulcerans : a novel model for studying the pathogenesis of Buruli ulcer disease

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    Buruli ulcer (BU) is a slowly progressing, necrotising disease of the skin caused by infection with Mycobacterium ulcerans. Non-ulcerative manifestations are nodules, plaques and oedema, which may progress to ulceration of large parts of the skin. Histopathologically, BU is characterized by coagulative necrosis, fat cell ghosts, epidermal hyperplasia, clusters of extracellular acid fast bacilli (AFB) in the subcutaneous tissue and lack of major inflammatory infiltration. The mode of transmission of BU is not clear and there is only limited information on the early pathogenesis of the disease available.; For evaluating the potential of the pig as experimental infection model for BU, we infected pigs subcutaneously with different doses of M. ulcerans. The infected skin sites were excised 2.5 or 6.5 weeks after infection and processed for histopathological analysis. With doses of 2×107 and 2×106 colony forming units (CFU) we observed the development of nodular lesions that subsequently progressed to ulcerative or plaque-like lesions. At lower inoculation doses signs of infection found after 2.5 weeks had spontaneously resolved at 6.5 weeks. The observed macroscopic and histopathological changes closely resembled those found in M. ulcerans disease in humans.; Our results demonstrate that the pig can be infected with M. ulcerans. Productive infection leads to the development of lesions that closely resemble human BU lesions. The pig infection model therefore has great potential for studying the early pathogenesis of BU and for the development of new therapeutic and prophylactic interventions

    Manual da qualidade Embrapa Suínos e Aves.

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    bitstream/item/58239/1/doc126.pdfProjeto/Plano de Ação: 05.05.50.500-06
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