1000 resultados para ddc: N3983


Relevância:

10.00% 10.00%

Publicador:

Resumo:

A pesquisa procura identificar e analisar as circunstâncias e motivações teóricas que levaram ao surgimento, no final do século XIX, da área de estudo denominada Documentação. Apresenta informações biográficas sobre os principais artífices deste projeto, os advogados e bibliógrafos belgas, Paul Otlet e Henri La Fontaine, que visaram ampliar a compreensão sobre o meio social e cultural em que atuaram. Procura ampliar a discussão sobre os fatores que motivaram em 1895 a proposta de organização racional de toda a produção intelectual do homem. Apresenta em linhas gerais a visão abrangente e integradora da Documentação que eliminando barreiras físicas, acessava acervos arquivísticos, bibliográficos e museológicos para o registro integral dos assuntos pesquisados. Discute a utilização da Classificação Decimal de Dewey (CDD) na criação do Repertório Bibliográfico Universal e analisa o processo que levou ao surgimento da Classificação Decimal Universal (CDU). Conclui sugerindo a inclusão desta visão extensiva e integradora da documentação ao referencial teórico da Ciência da Informação. Sugere que o resgate deste aporte teórico poderá contribuir para um melhor enfrentamento dos problemas da gestão do conhecimento registrado, produzido e acumulado até os dias atuais, nos mais diversos formatos, suportes e repositórios.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The epidemic of HIV/AIDS in the United States is constantly changing and evolving, starting from patient zero to now an estimated 650,000 to 900,000 Americans infected. The nature and course of HIV changed dramatically with the introduction of antiretrovirals. This discourse examines many different facets of HIV from the beginning where there wasn't any treatment for HIV until the present era of highly active antiretroviral therapy (HAART). By utilizing statistical analysis of clinical data, this paper examines where we were, where we are and projections as to where treatment of HIV/AIDS is headed.

Chapter Two describes the datasets that were used for the analyses. The primary database utilized was collected by myself from an outpatient HIV clinic. The data included dates from 1984 until the present. The second database was from the Multicenter AIDS Cohort Study (MACS) public dataset. The data from the MACS cover the time between 1984 and October 1992. Comparisons are made between both datasets.

Chapter Three discusses where we were. Before the first anti-HIV drugs (called antiretrovirals) were approved, there was no treatment to slow the progression of HIV. The first generation of antiretrovirals, reverse transcriptase inhibitors such as AZT (zidovudine), DDI (didanosine), DDC (zalcitabine), and D4T (stavudine) provided the first treatment for HIV. The first clinical trials showed that these antiretrovirals had a significant impact on increasing patient survival. The trials also showed that patients on these drugs had increased CD4+ T cell counts. Chapter Three examines the distributions of CD4 T cell counts. The results show that the estimated distributions of CD4 T cell counts are distinctly non-Gaussian. Thus distributional assumptions regarding CD4 T cell counts must be taken, into account when performing analyses with this marker. The results also show the estimated CD4 T cell distributions for each disease stage: asymptomatic, symptomatic and AIDS are non-Gaussian. Interestingly, the distribution of CD4 T cell counts for the asymptomatic period is significantly below that of the CD4 T cell distribution for the uninfected population suggesting that even in patients with no outward symptoms of HIV infection, there exists high levels of immunosuppression.

Chapter Four discusses where we are at present. HIV quickly grew resistant to reverse transcriptase inhibitors which were given sequentially as mono or dual therapy. As resistance grew, the positive effects of the reverse transcriptase inhibitors on CD4 T cell counts and survival dissipated. As the old era faded a new era characterized by a new class of drugs and new technology changed the way that we treat HIV-infected patients. Viral load assays were able to quantify the levels of HIV RNA in the blood. By quantifying the viral load, one now had a faster, more direct way to test antiretroviral regimen efficacy. Protease inhibitors, which attacked a different region of HIV than reverse transcriptase inhibitors, when used in combination with other antiretroviral agents were found to dramatically and significantly reduce the HIV RNA levels in the blood. Patients also experienced significant increases in CD4 T cell counts. For the first time in the epidemic, there was hope. It was hypothesized that with HAART, viral levels could be kept so low that the immune system as measured by CD4 T cell counts would be able to recover. If these viral levels could be kept low enough, it would be possible for the immune system to eradicate the virus. The hypothesis of immune reconstitution, that is bringing CD4 T cell counts up to levels seen in uninfected patients, is tested in Chapter Four. It was found that for these patients, there was not enough of a CD4 T cell increase to be consistent with the hypothesis of immune reconstitution.

In Chapter Five, the effectiveness of long-term HAART is analyzed. Survival analysis was conducted on 213 patients on long-term HAART. The primary endpoint was presence of an AIDS defining illness. A high level of clinical failure, or progression to an endpoint, was found.

Chapter Six yields insights into where we are going. New technology such as viral genotypic testing, that looks at the genetic structure of HIV and determines where mutations have occurred, has shown that HIV is capable of producing resistance mutations that confer multiple drug resistance. This section looks at resistance issues and speculates, ceterus parabis, where the state of HIV is going. This section first addresses viral genotype and the correlates of viral load and disease progression. A second analysis looks at patients who have failed their primary attempts at HAART and subsequent salvage therapy. It was found that salvage regimens, efforts to control viral replication through the administration of different combinations of antiretrovirals, were not effective in 90 percent of the population in controlling viral replication. Thus, primary attempts at therapy offer the best change of viral suppression and delay of disease progression. Documentation of transmission of drug-resistant virus suggests that the public health crisis of HIV is far from over. Drug resistant HIV can sustain the epidemic and hamper our efforts to treat HIV infection. The data presented suggest that the decrease in the morbidity and mortality due to HIV/AIDS is transient. Deaths due to HIV will increase and public health officials must prepare for this eventuality unless new treatments become available. These results also underscore the importance of the vaccine effort.

The final chapter looks at the economic issues related to HIV. The direct and indirect costs of treating HIV/AIDS are very high. For the first time in the epidemic, there exists treatment that can actually slow disease progression. The direct costs for HAART are estimated. It is estimated that the direct lifetime costs for treating each HIV infected patient with HAART is between $353,000 to $598,000 depending on how long HAART prolongs life. If one looks at the incremental cost per year of life saved it is only $101,000. This is comparable with the incremental costs per year of life saved from coronary artery bypass surgery.

Policy makers need to be aware that although HAART can delay disease progression, it is not a cure and HIV is not over. The results presented here suggest that the decreases in the morbidity and mortality due to HIV are transient. Policymakers need to be prepared for the eventual increase in AIDS incidence and mortality. Costs associated with HIV/AIDS are also projected to increase. The cost savings seen recently have been from the dramatic decreases in the incidence of AIDS defining opportunistic infections. As patients who have been on HAART the longest start to progress to AIDS, policymakers and insurance companies will find that the cost of treating HIV/AIDS will increase.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

By means of the second derivative of the ground-state and first-excited energy, the quantum phase transitions (QPTs) for the distorted diamond chain (DDC) with ferromagnetic and antiferromagnetic frustrated interactions and the trimerized case are investigated, respectively. Our results show the plentiful quantum phases owing to the spin interaction competitions in the model. Meanwhile, by using the transfer-matrix renormalization-group technique, we study the two-site thermal entanglement of the DDC model in the thermodynamic limit for a further understanding of the QPTs.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

为了探讨远紫外辐射对植物的损伤机理和紫杉的濒杉机制,本文就远紫外辐射对紫杉幼苗针叶膜脂过氧化及内源保护物质的影响进行了模拟研究,初步得到如下结果:UV-C 辐射紫杉针叶离体叶绿体可使膜脂过氧化产物丙二醛(MDA)含量增加,类胡萝卜素含量和光系统II(PS II)电子传递少性下降。UV-BC 辐射紫杉幼苗针叶可使叶绿体超氧离子自由基(O~-_2),单线态氧(~O_2),针叶有机自由基产额和H_2O_2含量有不同程度增加。针叶MDA,组织自动氧化速率及质膜相对透性也随辐射时间进程面增加。UV-BC处理初期超氧化物歧化酶(SOD),过氧化氢酶(CAT)活性及谷胱甘肽(GSH)含量均被诱导增高,21d后SOD活性开始下降,而GSH 含量和CAT活性始终高于对照。维生素C(ASA),类胡萝卜素(Car),叶绿素(chl),PS II 电子传递活性在处理期间始终呈下降趋势,其中ASA下降最明显。可溶性蛋白21d前变化不大,之后开始下降。外源活性氧清除剂苯甲酸钠和抗坏血酸对针叶膜脂过氧化有抑制作用;甲基紫精和DDC 对针叶膜脂过氧化有促进效果。根据上述结果推测,紫杉的UV-BC伤害可能是由于活性氧产生过剩和清除系统水平下降,而引起的膜脂过氧化损伤。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

实验室条件下用远紫外线 (UV BC)光源照射紫杉幼苗 ,随照射时间延长 ,针叶的离子渗出率、膜脂过氧化水平、组织自动氧化速率及H2 O2 含量显著增加 ,可溶性蛋白、抗坏血酸、类胡萝卜素和叶绿素含量下降 ,叶绿体光系统II电子传递活性显著下降 ,外源活性氧清除剂苯甲酸钠和抗坏血酸对针叶膜脂过氧化有抑制作用 ;甲基紫精和DDC对针叶膜脂过氧化有促进效果 ,远紫外线引起的紫杉伤害可能和针叶树的越冬光氧化伤害有类似之处 .紫杉苗对紫外辐射的抗性远高于一般农作物 .

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In diesem Beitrag weisen wir auf die Bedeutung hin, die selbstorganisierte Projektgruppen von Studierenden für das (Aus-)Bildungsziel der überfachlichen Kompetenzentwicklung haben können. Nach einem kurzen Überblick über den aktuellen Stand der Förderung überfachlicher Kompetenzen an Hochschulen stellen wir am Beispiel des Augsburger „Begleitstudiums Problemlösekompetenz“ einen Ansatz zur Kompetenzentwicklung vor, der auf der Partizipation in studentischen Praxisgemeinschaften beruht. Wir erläutern vor diesem Hintergrund, wie sich selbstorganisierte Projektgruppen von Studierenden von anderen Gruppenformen im Rahmen von Lehrveranstaltungen unterscheiden, und machen anhand eines Beispiels deutlich, welchen Mehrwert diese Praxisgemeinschaften gegenüber anderen Ansätzen zur überfachlichen Kompetenzförderung an Hochschulen haben. (DIPF/ Orig.)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Bisher stehen sich in der deutschen Jugendforschung mit dem Transitions- und Moratoriumsgedanken zwei Konzepte zur Beschreibung der Jugendphase gegenüber, deren ergänzender Charakter bisher kaum Beachtung gefunden hat. Um eine Verknüpfung leisten zu können, sollen beide Auffassungen von Jugend kurz skizziert und in die Beschreibung einer Typologie jugendlicher Entwicklungswege überführt werden. Im zweiten Teil werden auf der Basis von Sekundäranalysen empirische Evidenzen aufgezeigt, die eine Vertiefung der theoretischen Herangehensweise aussichtsreich erscheinen lassen. (DIPF/Orig.)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Der Artikel befasst sich mit der europäischen Forschungsförderpolitik im Hinblick auf die Sozialwissenschaften. Derzeit laufen die Vorbereitungen für das nächste EU-Forschungsrahmenprogramm, das ab 2014 bis 2020 gültig sein wird. Es wird den Namen Horizon 2020 erhalten. Die Analyse skizziert die verschiedenen Aktivitäten, die nationale und europäische Erziehungswissenschaftsverbände entfaltet haben, um eine Repräsentation der Sozialwissenschaften im nächsten Rahmenprogramm zu gewährleisten. (DIPF/Orig.)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Anhand eines schulischen Dokumentes zur Methode des Trainingsraums werden Anspruch und Umsetzung der Methode analysiert. Der Trainingsraum verspricht Lehrerinnen und Lehrern eine Methode an die Hand zu geben, um Unterrichtsstörungen erzieherisch in den Griff zu bekommen und vor allem: fortlaufenden Unterricht zu ermöglichen. Das Beispiel zeigt, inwieweit eine Verlagerung des Disziplinierungsproblems in den Trainingsraum doch wieder an den Ort des Geschehens - den Klassenraum - zurückführt. (DIPF/Autor)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Vor- und Nachteile im Vergleich von herkömmlichem zu elektronischem Publizieren werden erläutert. Mit Bezug auf eine DFG-Studie zum "Publikations- und Rezeptionsverhalten unter besonderer Berücksichtigung von Open Access" wird die Situation speziell in der Erziehungswissenschaft reflektiert und dabei besonders auf das Projekt "Fachportal Pädagogik" eingegangen, das u.a. Qualitätssicherung und Langzeitverfügbarkeit von elektronisch vorliegender erziehungswissenschaftlicher Fachinformation zum Ziel hat. (DIPF/pr)