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Electrogenetherapy of established B16 murine melanoma by using an expression plasmid for HIV-1 viral protein RMcCray, Andrea Nicole 01 June 2006 (has links)
Novel therapies and delivery methods directed against malignancies such as melanoma, and particularly metastatic melanoma, are needed. The HIV-1 accessory protein Vpr (viral protein R) has previously been demonstrated to induce G2 cell cycle arrest as well as in vitro growth inhibition/killing of numerous tumor cell lines. In vivo electroporation has been utilized as an effective delivery method for pharmacologic agents as well as DNA plasmids that express "therapeutic" proteins and has been targeted to various tissues including malignant tumors. In this study, we assessed the ability of electroporation-mediated delivery of Vpr plasmid (pVpr) to induce growth attenuation or complete tumor regression in C57BL/6 mice with subcutaneous B16.F10 melanoma lesions.
To assess the administration of intratumoral delivery of pVpr with in vivo electroporation, a range of Vpr plasmid dosages, electroporation parameters, and treatment days were evaluated in a subcutaneous B16 murine melanoma model. pVpr was injected directly into the tumors. Immediately following the injection, the subcutaneous tumors were electroporated. Treatment with 25 microgram or 100 microgram of pVpr plus electroporation on days 0 and 4 resulted in complete tumor regressions with long-term survival in 14.3% and 7.1% of the mice, respectively. In order to optimize the treatment regimen, B16 tumors were treated on days 0, 2, and 4 with 100 microgram pVpr plus electroporation which resulted in 50% of the mice with complete tumor regressions and long-term survival. Additional investigations revealed intratumoral Vpr expression and demonstrated that apoptosis was the mechanism by which Vpr caused tumor regression in vivo.
This study confirmed that treatment with 100 microgram of pVpr plus electroporation led to durable complete regressions in established murine melanoma lesions. The pVpr plus electroporation treatment regimen has induced complete regressions in mice as well as resistance to tumor challenge in some of the animals. This is the first comprehensive study demonstrating the ability of Vpr, when delivered as a DNA expression plasmid with in vivo electroporation, to induce complete tumor regressions coupled with long- term survival of mice in a highly aggressive and metastatic solid tumor model.
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Symptoms, prehospital delay and long-term survival in men vs. women with myocardial infarction : a combined register and qualitative studyIsaksson, Rose-Marie January 2011 (has links)
The general aim of this thesis was to study symptoms, prehospital delay and time trends in long-term survival in men and women with myocardial infarction (MI). The study was based on quantitative and qualitative data collections. Study I was based on The Northern Sweden MONICA Myocardial Infarction Registry, 1989-2003, including 5072 men and 1470 women with a confirmed MI. Symptoms and prehospital delay were described and trends over time according to sex and age were studied. Typical pain was present in 86% of the men and 81% of the women and typical symptoms were more common among younger persons than older persons. Up to the age of 65 no gender differences were seen in the prehospital delay. In the oldest age group (65–74 years) time to hospital was longer than among the younger group, especially among women. Study II was based on individual interviews with 20 men with a first confirmed MI, representing the age range 65-80 years, about their experiences during the prehospital phase. The interviews were analyzed using qualitative content analysis. The interviewed older men described how the symptoms developed from diffuse ill-being, to a cluster of severe symptoms. The men had difficulties to relate to the experienced symptoms, which did not correspond to their expectations about an MI, and about whether they should seek medical care. By using different strategies the participants initially tried to understand, reduce, or treat the symptoms by themselves, with a desire to maintain an ordinary life. As the symptoms evolved to a persistent and alarming chest pain, the men realized the seriousness in the perceived symptoms, that all strategies were inefficacious and they came to the decision to seek medical care. Study III was based on individual interviews with 20 women with a first confirmed MI, representing the age range 65-80 years, about their experiences during the prehospital phase. The interviews were analyzed using qualitative content analysis. The interviewed older women described how the symptoms were perceived as a stepwise evolvement from intangible and bodily sensations to a more distinct, persistent and finally overwhelming chest pain. The women struggled against the symptoms and used different strategies, by downplaying and neglecting the symptoms in order to maintain control over their ordinary lives and maintain the social responsibilities. As the symptoms evolved to a persistent and overwhelming chest pain the women realized the seriousness in the perceived symptoms, they were not able to struggle against them anymore and they came to the decision to seek medical care. Study IV was based on The Northern Sweden MONICA Myocardial Infarction Registry which was linked to The Swedish National Cause of Death Registry for 6762 men and 1868 women, 25 to 64 years of age, with a first MI during 1985-2006. Also deaths before admission to hospital were included. Follow-up ended on August 30, 2008. Between 1985 and 2006 long-term survival after a first MI increased in both men and women. Over the whole 23-year period women showed a 9 percent higher survival then men. This slight difference was due to lower risk for women to die before reaching hospital, and during the last period similar rates of long time survival were noted in men and women. In conclusion there were no major differences between men and women in symptoms, prehospital delay or long-term survival. However, older patients had fewer typical symptoms and longer prehospital delay, especially among women. The prehospital phase was found to be multifaceted with experiences difficult to interpret in both men and women, with a dynamic development of symptoms, conceptions and expectations while the participants strove to maintain the ordinary and familiar life. The symptoms experienced presented a more heterogeneous and complex picture in both men and women than is usually described in the literature. Women under the age of 65 have a slightly higher age-adjusted long-term survival than men. Over a 23-year period long-term survival has improved similarly in both men and women. / Det övergripande syftet med avhandlingen var att beskriva symtom, prehospital fördröjning och långtidsöverlevnad hos män och kvinnor med hjärtinfarkt. Studien baserades på kvantitativa och kvalitativa datainsamlingar. Delstudie I baserades på data från hjärtinfarktregistret vid The Northern Sweden MONICA Study under åren 1989-2003, inkluderande 5072 män och 1470 kvinnor, med fastställd hjärtinfarkt. Symtom och tid från symtomstart till medicinsk vård beskrevs och tidstrender relaterades till kön och ålder. Resultatet visade att typisk smärta förelåg hos 86% av männen och 81% av kvinnorna och att typiska symtom var mer förekommande hos de yngre. Upp till 65 års ålder fanns inga könsskillnader mellan symtomstart och tid till medicinsk vård. I den äldsta åldersgruppen (65-74 år) var tiden till sjukvård längre, främst hos kvinnor. Delstudie II baserades på individuella intervjuer med 20 män, mellan 65 och 80 år som drabbats av sin första hjärtinfarkt, om hur de upplevde den prehospitala fasen. Intervjuerna analyserades med hjälp av kvalitativ innehållsanalys. Männen beskrev hur symtomen utvecklades från ett diffust illabefinnande, till ett kluster av svåra symtom. De hade svårt att relatera till de upplevda symtomen som inte motsvarade deras föreställningar om hur symtom på hjärtinfarkt tar sig uttryck, och hade svårt att veta om de skulle söka vård. Deltagarna vidtog olika strategier för att försöka förstå, minska eller behandla symtomen på egen hand, i en strävan att få livet att fortgå som vanligt. När symtomen utvecklats till en alarmerande och ihållande bröstsmärta insåg männen allvarlighetsgraden i symtombilden och att strategierna för att hantera symtomen var verkningslösa och beslutade att söka vård. Delstudie III baserades på individuella intervjuer med 20 kvinnor, med sin första hjärtinfarkt i åldern 65-80 år, för att få en djupare förståelse för hur de upplevde den prehospitala fasen. Intervjuerna analyserades med hjälp av kvalitativ innehållsanalys. De äldre kvinnorna beskrev hur symtomen stegvis utvecklades från ogripbara och kroppsliga förnimmelser, mot en mer distinkt, ihållande och slutligen överväldigande bröstsmärta. Kvinnorna kämpade mot symtomen och använde olika strategier, som att tona ner och negligera symtomen för att behålla kontrollen över livssituationen och upprätthålla det sociala ansvarstagandet. När symtomen utvecklades till en ihållande och överväldigande bröstsmärta insåg kvinnorna allvarlighetsgraden i symtombilden, att de inte kunde kämpa mot symtomen längre och beslutade att söka vård. Delstudie IV inkluderade patienter med en första hjärtinfarkt mellan åren 1985 och 2006 validerade i hjärtinfarktregistret vid The Northern Sweden MONICA Study i Norr- och Västerbotten som följdes upp i dödsorsaksregistret tom 30 augusti, 2008. Totalt 6762 män och 1868 kvinnor i åldern 25-64 studerades. Även patienter som avled före sjukhusvård inkluderades. Resultatet visade att mellan 1985 och 2006 förbättrades långtidsöverlevnaden efter en första hjärtinfarkt hos både män och kvinnor. Över hela 23-års perioden hade kvinnor 9 procents högre åldersjusterad överlevnad jämfört med män. Denna skillnad berodde på lägre risk för kvinnor att avlida innan de nådde sjukhuset. Under den sista tidsperioden var långtidsöverlevnad lika hos både män och kvinnor. Sammanfattningsvis visar denna studie inga stora skillnader mellan män och kvinnors symtom, prehospitala fördröjning eller långtidsöverlevnad. Dock hade äldre patienter färre typiska symtom och längre prehospital fördröjning, särskilt hos kvinnor. Den prehospitala fasen var en mångfasetterad och svårtolkad upplevelse hos både män och kvinnor, med en dynamisk utveckling av symtom, föreställningar och förväntningar, samtidigt som deltagarna strävade efter att upprätthålla det vardagliga och välbekanta livet. Symtomen vid hjärtinfarkten var en mer heterogen och komplex upplevelse hos både män och kvinnor än vad som vanligtvis beskrivs i litteraturen. Över en 23-års period har långtidsöverlevnaden efter en första hjärtinfarkt förbättrats hos både män och kvinnor. Kvinnor under 65 år har en något högre långtidsöverlevnad jämfört med män.
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Modelos de análise de sobrevivência aplicados ao estudo do comportamento de retorno do doador de sangue / Survival Analysis Models applied to the Study of Blood Donor Return Behavior.Lourençon, Adriana de Fatima 20 September 2007 (has links)
Notícias de escassez no mundo inteiro, dada a crescente demanda e o rigor na triagem clínica, levaram a necessidade de investigar métodos que mensurem o comportamento de retorno do doador de sangue, sobretudo o indivíduo que manifesta a intenção voluntária em doar. Curvas de Sobrevivência entre outros métodos estatísticos são amplamente estudados na literatura com o intuito de obter uma estimativa da chance de um doador vir a realizar uma subseqüente doação, associado ao seu perfil. O objetivo do presente estudo é identificar modelos estatísticos capazes de descrever esse comportamento utilizan do os registros do Centro Regional de Hemoterapia de Ribeirão Preto. A cons trução de modelos de longa-duração, por exemplo, pode ser um meio de evidenciar possíveis subgrupos mais propensos a retornar, além de estimar a proporção de doadores que jamais retornarão. Entre os resultados, obser vamos que apenas 40% dos doadores voluntários retornaram após um ano decorrido da primeira doação, e 20% destes jamais retornarão. O ajuste do modelo longaduração possibilitou ainda indicar alguns subgrupos de doadores prováveis e improváveis de retornar, porém tais resultados reforçam as evidências de que a motivação intrínseca é o que leva o individuo a retornar. / Reports of worldwide shortages due the increased demand and rigor of clinical screening have led to the necessity to investigate methods that measure blood donor return behavior, mainly regarding individuals who manifest the voluntary intention to donate. Survival curves, among others statistical methods, have been extensively studied in the literature in order to estimate the likelihood of a donor to make another donation, associated with his profile. The aim of the present study was to identify statistical models describing this behavior using information from the Regional Hemotherapy Center of Ribeirão Preto. The construction of long-term survival model can be a useful instrument for determining the groups more likely to donate, as well as the proportion of donors who will never return. The results obtained revealed that only 40% of the volunteer primary donors return for a new donation one year after the first, with the estimate that 20% will never return. The construction of long-term survival model still facilitated to indicate some groups likely and unlike ly donors to donate, even so such re sults reinforce the evidences that the intrinsic motivation is what prompts a donor to return.
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Modelos de análise de sobrevivência aplicados ao estudo do comportamento de retorno do doador de sangue / Survival Analysis Models applied to the Study of Blood Donor Return Behavior.Adriana de Fatima Lourençon 20 September 2007 (has links)
Notícias de escassez no mundo inteiro, dada a crescente demanda e o rigor na triagem clínica, levaram a necessidade de investigar métodos que mensurem o comportamento de retorno do doador de sangue, sobretudo o indivíduo que manifesta a intenção voluntária em doar. Curvas de Sobrevivência entre outros métodos estatísticos são amplamente estudados na literatura com o intuito de obter uma estimativa da chance de um doador vir a realizar uma subseqüente doação, associado ao seu perfil. O objetivo do presente estudo é identificar modelos estatísticos capazes de descrever esse comportamento utilizan do os registros do Centro Regional de Hemoterapia de Ribeirão Preto. A cons trução de modelos de longa-duração, por exemplo, pode ser um meio de evidenciar possíveis subgrupos mais propensos a retornar, além de estimar a proporção de doadores que jamais retornarão. Entre os resultados, obser vamos que apenas 40% dos doadores voluntários retornaram após um ano decorrido da primeira doação, e 20% destes jamais retornarão. O ajuste do modelo longaduração possibilitou ainda indicar alguns subgrupos de doadores prováveis e improváveis de retornar, porém tais resultados reforçam as evidências de que a motivação intrínseca é o que leva o individuo a retornar. / Reports of worldwide shortages due the increased demand and rigor of clinical screening have led to the necessity to investigate methods that measure blood donor return behavior, mainly regarding individuals who manifest the voluntary intention to donate. Survival curves, among others statistical methods, have been extensively studied in the literature in order to estimate the likelihood of a donor to make another donation, associated with his profile. The aim of the present study was to identify statistical models describing this behavior using information from the Regional Hemotherapy Center of Ribeirão Preto. The construction of long-term survival model can be a useful instrument for determining the groups more likely to donate, as well as the proportion of donors who will never return. The results obtained revealed that only 40% of the volunteer primary donors return for a new donation one year after the first, with the estimate that 20% will never return. The construction of long-term survival model still facilitated to indicate some groups likely and unlike ly donors to donate, even so such re sults reinforce the evidences that the intrinsic motivation is what prompts a donor to return.
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Mécanismes moléculaires de la survie à long terme chez Propionibacterium freudenreichii / Molecular mechanisms of long-term survival in Propionibacterium freudenreichiiFigueira Aburjaile, Flavia 09 December 2015 (has links)
Propionibacterium freudenreichii est une bactérie très utilisée par l’industrie laitière. Elle appartient aux Actinomycètes connus pour leur survie pendant de longues périodes, dans des conditions environnementales défavorables. Pour mieux comprendre ce phénomène, la caractérisation phénotypique de 8 souches de P. freudenreichii a été réalisée sur 11 jours dans un milieu en carence nutritionnelle. Le taux de survie bactérienne a été mesuré par densité optique, par énumération et évaluation de la viabilité cellulaire. En outre, l’absence de lyse cellulaire a été évaluée par PCR quantitative. La croissance de P. freudenreichii a été décrite en phases exponentielle, stationnaire, stationnaire tardive et survie à long terme.Dans nos conditions expérimentales pendant la période de survie à long terme, les bactéries sont restées viables. La caractérisation phénotypique a montré que P. freudenreichii CIRM-BIA138 était la plus résistante à la carence nutritionnelle et entrait dans un état viable mais non-cultivable. Cette souche a été utilisée pour une étude fonctionnelle par RNA-Seq ainsi que pour des analyses biochimiques sur les surnageants de culture, en phases exponentielle et stationnaire. L’association de ces données transcriptomiques et métabolomiques a permis de déduire les stratégies impliquées dans la survie de cette bactérie. La préparation à l’état de dormance, la diminution du métabolisme et l’utilisation de sources alternatives d’énergie semblent impliquées dans l’adaptation et la persistence de P. freudenreichii CIRM-BIA138 en carence nutritionnelle durant de long / Propionibacterium freudenreichii is a dairy bacterium belonging to the Actinobacteria group, which is known to survive for long periods in harsh environmental conditions. In order to investigate the long-term survival phenomenon in P. freudenreichii, 8 strains were phenotypically characterized for a period of 11 days in nutrient shortage condition. Bacterial survival rate was assessed by optical density, CFU counting and live-dead cellular viability. In addition, the absence of cell lysis was evaluated by quantitative PCR. P. freudenreichii growth phases were classified as exponential, stationary, late stationary and long-term survival. Moreover, it was observed that bacterial viability was maintained during long-term survival.Phenotypical characterization indicated that P. freudenreichii CIRM-BIA138 was more resistant to nutrient shortage being able to enter into a viable but nonculturable dormant state. In addition, functional studies of this strain were conducted by RNA-Seq on cultures sampled in exponential and stationary growth phases. Concomitantly, several biochemical analyses were carried out on the culture supernatant. An integrative approach of metabolomic and transcriptomic data allowed us to infer strategies associated with the survival of this bacterium, such as preparation for the dormant state, slow down of metabolic activity and utilization of alternative sources of energy, which altogether might allow P. freudenreichii CIRM-BIA 138 to adapt and persist through nutrient shortage for long periods.
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Funkce proteinu Pmp3p / The function of Pmp3p proteinBelovičová, Martina January 2011 (has links)
During development of Saccharomyces cerevisiae colonies on solid substrate, metabolic transitions occur, which are reflected by pH changes around the colony and also by changes in cell membrane potential. Analyses of transmemebrane potential oscillations revealed a function for Plasma Membrane Proteolipid 3 (Pmp3p) in this process. The thesis discusses possible function of Pmp3p protein mainly on the basis of direct observation of Pmp3p localization in vivo under variety of cultivation conditions. Yeast strains with different variants of Pmp3p protein fused with different protein tags that allow monitoring of Pmp3p localization and concentration in cells were prepared by homologous recombination. Localization of Pmp3p in the plasma membrane and in lipid particles was found. The Pmp3p level in cells was stable during development of colonies growing on either respirative or fermentative carbon source medium. High concentration of extracellular sodium chloride did not evoke increase in Pmp3p-GFP concentration. Key words: Pmp3p, proteolipids, UPF0057 (PMP3) family, Saccharomyces cerevisiae, long term survival, lipid particles
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Biomarkers for Non-Invasive Stratification of Coronary Artery Disease and Prognostic Impact on Long-Term Survival in Patients with Stable Coronary Heart DiseaseNetto, Jeffrey, Teren, Andrej, Burkhardt, Ralph, Willenberg, Anja, Beutner, Frank, Henger, Sylvia, Schuler, Gerhard, Thiele, Holger, Isermann, Berend, Thiery, Joachim, Scholz, Markus, Kaiser, Thorsten 15 January 2024 (has links)
Knowledge about cardiac and inflammatory biomarkers in patients with stable coronary
artery disease (CAD) is limited. To address this, we analyzed 3072 patients (36% female) with a
median follow-up of 10 years in the Leipzig LIFE Heart Study with suspected CAD with coronary
angiography. Selected biomarkers included troponin T (hsTNT), N-terminal pro B-type natriuretic
peptide (NT-proBNP), copeptin, C-reactive protein (hsCRP), and interleukin-6 (IL-6). Patients were
stratified by CAD severity: CAD0 (no sclerosis), CAD1 (non-obstructive, i.e., stenosis < 50%), and
CAD2 (one stenosis 50%). Group comparison (GC) included GC1: CAD0 + 1 vs. CAD2; GC2:
CAD0 vs. CAD1 + 2. CAD0, CAD1, and CAD2 were apparent in 1271, 631, and 1170 patients,
respectively. Adjusted for classical risk factors, hs-cTnT, NT-proBNP, and IL-6 differed significantly
in both GC and hsCRP only in GC2. After multivariate analysis, hs-cTnT, NT-proBNP, and IL-6
remained significant in GC1. In GC2, hs-cTnT (p < 0.001) and copeptin (p = 0.014) reached significance.
Ten-year survival in groups CAD0, CAD1, and CAD2 was 88.3%, 77.3%, and 72.4%. Incorporation of
hs-cTnT, NT-proBNP, copeptin, and IL-6 improved risk prediction (p < 0.001). The studied cardiac
and inflammatory biomarkers enable fast and precise non-invasive identification of mortality risk in
CAD patients, allowing the tailoring of primary and secondary CAD prevention.
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Kirtavietėse paliekamų pušies biologinės įvairovės medžių ilgalaikio išlikimo neigiamiems aplinkos veiksniams tyrimas Nemenčinės miškų urėdijoje / Leave on harvest sites of pine of trees of long-term biodiversity of survival and adverse environmental factors inverstigation nemenčinės in forestGedminas, Džiugas 17 June 2014 (has links)
Baigiamajame darbe aptariami kirtavietėse paliekamų pušies biologinės įvairovės medžių ilgalaikio išlikimo neigiamiems aplinkos veiksniams tyrimo rezultatai.
Darbo tikslas – surinkti ir įvertinti Nemenčinės miškų urėdijos kirtavietėse paliekamų biologinės įvairovės medžių būklę, kiekį ir išlikimą kirtavietėje.
Darbo objektas – plyno kirtimo biržės ir jose palikti biologinės įvairovės medžiai.
Darbo metodika. Mokslinės literatūros analizės pagrindu teoriniu aspektu buvo gilinamasi į biologinės įvairovės svarbą ir jos apsaugos priemonių kūrimą bei taikymą. Šiam tikslui pasiekti studijuojamos lietuvių bei užsienio autorių knygos, moksliniai straipsniai, internetinė medžiaga, susijusi su nagrinėjama tema. Tyrimo metu buvo analizuojami keli parametrai: medžių atsparumas aplinkos poveikiams, medžių ilgalaikis išlikimas priklausantis nuo kirtavietės ploto, reljefo, paklotės storio.
Darbo rezultatai.
Tyrimo metu buvo susisteminta medžių paliekamų bioįvairovei tendencija. Buvo tirtos trijų skirtingų kirtimų metų šešios kirtavietės. Tyrimo metu nustatyta, kad į medžių paliekamų bioįvairovei būklę vis daugiau atsižvelgiama. Kirtimų metu paliekama vis didesnės įvairovės medžių, kurie atrenkami pagal normatyvus, kad būtų kuo ilgaamžiškesnis jų išlikimas. Nemenčinės miškų urėdijoje kirtavietėse po kirtimo praėjus daugiau nei 5 metams daugiausia išliko gyvybingų – žalių – medžių 77 proc. ir tik 23 proc. kitokių nudžiuvusių, nulaužtų ir išverstų medžių. Dauguma žalių medžių dažniausiai... [toliau žr. visą tekstą] / The master thesis presents the pine tree biodiversity and it‘s condition in the clear-felled area had been evaluated in forest areas.
Aim of the work – assemble and evaluate the condition, quantity and survival of the trees, left for biological diversity in clear cutting areas in Nemenčinės forestry enterprise.
Object of the work – The trees left for the biological diversity in clear cutting areas.
Methods of the work – the theoretical aspect of the importance of biodiversity and its conservation and development of the application were analyzed in literature. To achieve this, the Lithuanian and foreign authors, books, scientific articles, online material related to the topic were studied. The study included the analysis of several parameters: tree resistance to environmental factors, long-term survival of the trees from harvesting area, terrain.
Result of work - during the studies the biodiversity trend of the pine trees left in the wood clearcuts was structured. Six clearings in three different harvest years have been tested. It have been stated that more and more attention for the biodiversity is considered. During the clear cuttings bigger variety of the trees are left. These trees are selected according to the guidelines in order to make the more durable. After more than 5 years in the Nemenčinės forestry enterprise - the majority of trees in the clearcut forest - 77 % of them - are well growing, lush green trees. However, 23 % of the trees are dead, twisted or dumped... [to full text]
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Modelos de sobrevivência de longa-duração : uma abordagem unificadaIritani, Mateus Rodrigues 13 June 2008 (has links)
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Previous issue date: 2008-06-13 / Financiadora de Estudos e Projetos / In survival analysis some studies show a meaningful cure rate after treatment followup, so considering standard survival models can not be appropriate. In this work is extended the long-term survival model proposed by Chen, Ibrahim and Sinha (1999) via generating function of a real sequence introduced by Feller (1967). This new formulation is the uni_cation of the long-term survival models proposed by Rodrigues el al. (2008). Also, as in Rodrigues el al. (2008) it is shown that the long-term survival generating function satis_es the proportional hazard property if only if the number of competing causes related to the occurence of a event of interest follows a Poisson distribution. A real data set is considered to illustrate this approach. / Em análise de sobrevivência, determinados estudos caracterizam-se por apresentar uma fração significativa de sobreviventes, ou seja, pacientes em tratamento que não apresentaram o evento de interesse, mesmo após um longo período de acompanhamento. Assim considerar modelos de sobrevivência usuais, que assumem que a função de sobrevivência converge para zero quando a variável tempo tende a infinito, pode não ser adequado. Nesse trabalho é apresentado uma extensão do modelo proposto por Chen, Ibrahim e Sinha (1999), usando a função geradora de uma sequência de números reais introduzida por Feller (1967). Essa extensão possibilitou o desenvolvimento de uma teoria unificada para os modelos de sobrevivência de longa-duração, Rodrigues et al. (2008). Mostra-se que modelos já existentes na literatura são considerados casos particulares da teoria unificada, por exemplo, o modelo de Berkson & Gage (1952). Também tem-se em Rodrigues et al. (2008), que a função geradora de longa-duração satisfaz a propriedade de risco proporcional se, e somente se, o número de causas competitivas relacionadas a ocorrência do evento de interesse segue uma distribuição de Poisson. Como ilutração utiliza-se um conjunto de dados reais.
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Ekologisk aspekt som mervärde : En studie om långsiktig överlevnad för ekologiskt nischade livsmedelsföretagNilsson, Mikaela, Herrala, Carolin January 2009 (has links)
<p><strong>Background: </strong>With the increased globalization food prices went down for a while, only to skyrocket to new levels. Prices of organic food, which already were more expensive than conventional, are now even more expensive. The current financial crisis results in reduced consumption which creates a threat to the smaller grocery stores. Globalization and the increased competition have had a negative impact on the environment but at the same time the desire to solve these issues has increased appreciably. The environmental aspect has been given higher priority by the individual, which led to a wider range of organic products and dramatically increased the number of stores selling organic products, leading to a greater competition among the stores selling organic food. <strong> </strong></p><p><strong></strong><strong>Problem definition: </strong>What factors are important for organic retail business long term survival?</p><p><strong>Purpose:</strong> Trough case studies analyze and evaluate the organic niche retail companies’ strategies of marketing.</p><p><strong>Methods:</strong> This study is based on both qualitative and quantitative research methods. The qualitative data has been gathered through interviews with each company, on the management and employee level, at five different companies. The quantitative data has been gathered through a customer survey with the customers of each company.</p><p><strong>Results:</strong> All of the studied companies used development as their marketing strategy, offering surplus values to the customers by integrating the organic aspect into all levels within the company. Four out of five cases had high involved customers and a high level of interaction between the customers and the personnel. High involved customers with development as comprehensive strategy creates a combination leading to long term survival.</p><p><strong>Conclusion:</strong> On the very competitive retail market following factors are important for the long term survival of the companies with organic niches; that the organic aspect is integrated with all involved parties, that the company has a well working internal marketing, that the staff generates a high level of service for customers and that they can provide customers with high level of knowledge about the organic products.</p><p> </p><p> </p> / <p><strong>Bakgrund: </strong>I takt med den ökade globaliseringen har livsmedelpriserna pressats för att sedan ha vänt och istället nått rekordhöga höjder. Ekologiska matvaror som redan varit dyrare, blir ännu dyrare. Den rådande finanskrisen leder till en minskad konsumtion vilket hotar de små livsmedelsbutikerna. Globaliseringen och den medförda konkurrensen har haft en negativ påverkan på miljön i form av miljö- och klimatproblem, däremot har viljan att lösa dem ökat markant, vilket avspeglas genom ett globalt engagemang för miljöfrågor. Den enskilde individen prioriterar miljöaspekten allt högre, vilket har lett till att fler aktörer, både stora kedjor och små affärer, gått in på den ekologiska livsmedelsmarknaden, vilket medför en starkt ökad konkurrens för de små ekologiskt nischade livsmedelsföretagen.<strong> </strong></p><p><strong>Problemformulering: </strong>Vilka faktorer är viktiga för miljönischade livsmedelsbutikers långsiktiga överlevnad?</p><p><strong>Syfte: </strong>Genom en fallstudie analysera och utvärdera de ekologiskt nischade livsmedelsbutikernas marknadsföringsstrategier.</p><p><strong>Metod: </strong>Studien är baserad på både kvalitativ och kvantitativ data. Kvalitativ data har hämtats genom intervjuer på två nivåer, ledning och anställda, hos fem olika livsmedelsföretag. Intervjusvaren jämförs sedan i en GAP-analys för att upptäcka eventuella gap. Kvantitativ data har insamlats genom enkätundersökning med kunder till respektive livsmedelsföretag.</p><p><strong>Resultat: </strong>Samtliga livsmedelsföretag i undersökningen använde utveckling som marknadsföringsstrategi, genom att den ekologiska aspekten integrerades i alla nivåer i företaget. I fyra av fem fall var kunderna höginvolverade och en hög interaktion förekom mellan kund och personal. Den ovanstående kombinationen med höginvolverade kunder och utveckling som övergripande strategi för företagen, ger resultatet långsiktig överlevnad.</p><p><strong>Slutsats: </strong>För att de ekologiska livsmedelföretagen skall kunna överleva på den konkurrensutsatta marknaden, är följande faktorer viktiga; att den ekologiska aspekten integreras hos alla inblandade parter, att företaget har en fungerande intern marknadsföring, att personalen har en hög servicenivå gentemot kund och att personalen har en hög specialkunskap om de ekologiska produkterna att tillhandahålla kunderna med.</p><p> </p><p> </p>
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