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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
251

Vztah mezi dlouhověkostí a známkami nespecifického stresu na kostře v raně středověké populaci Velké Moravy / Relationship between longevity and non-specific stress in the Early Medieval Moravian population

Zazvonilová, Eliška January 2017 (has links)
Opinions on the relationship between non-specific stress and age at death on adults are not uniform. The inspiration for our diploma thesis was a study by Croatian authors Becic et al. (2014) who reported that individuals with non-specific stress indicators (cribra orbitalia) lived longer. Our aims were following: to estimate the longevity and compared influence of used methods on the relationship between non-specific stress and age at death, to test the relationship between age at death and non-specific stress indicators, particularly cribra orbitalia and linear enamel hypoplasia, and also to test the relationship between non-specific stress indicators and stature. Methods for age estimation are divided into two parts, methods used in the study Becic et al. (2014) and our method selection chosen from the literature appropriate for the oldest individuals. In this study, the presence of cribra orbitalia and enamel hypoplasia was observed in 294 adult individuals (111 women, 135 men and 48 undetermined individuals) from the Early Mediaeval (9th - 10th century) Slavic skeletal series at Mikulčice (Great Moravia), IIIrd church. When comparing age at death estimated by two different technics we found reduced age at death for the individuals with cribra orbitalia and also with enamel hypoplasia. There...
252

The Effects of Probiotics on High Sugar-Induced Type 2 Diabetes Mellitus Symptoms in Drosophila melanogaster

Al-Ghamdi, Yasser January 2019 (has links)
Background: Type 2 diabetes mellitus is a metabolic disorder characterized by the rise of fasting plasma glucose from its normal range (≥125mg/dl). It is marked by insufficient production of insulin from pancreatic β-cells as a result of failed compensation due to insulin resistance. Several treatments are available for the disorder, which mainly focus on improving the sensitivity of insulin in different body tissues. Recently, probiotics were suggested as candidate treatments for type 2 diabetes and for extending lifespan as well. This experiment aims to investigate such claims using Drosophila melanogaster as a disease model.   Results: Other than the observed low average weights in treated larva samples, probiotics did not show any other significant results in affecting the length, glucose, glycogen, and trehalose levels (One-Way ANOVA and Kruskal-Wallis, p>0.05). Real-time PCR was only carried out once. Thus, no statistical tests were reliable enough to analyse the data obtained. The longevity study, on the other hand, did show significance (Log-rank (Mantel-Cox) test and Gehan-Breslow-Wilcoxon test, p<0.0001), as the probiotic Bifidobacterium lactis extended the lifespan of adult flies feeding on a high sugar diet significantly when compared to the control ones feeding on only high sugar diet without probiotics.   Conclusion: Except for weight measurements, none of the other results was reliable enough to make a concrete conclusion on whether the treatments indeed worked in reversing type 2 diabetes symptoms or not. Real-time PCR results did show some effects of some of the treatments at different developmental stages. However, unless Real-time PCR is repeated at least once using the same protocol, no deduction can be made. Additionally, the data obtained hint that the dosage used (0.025 g) was too high for larvae and adult flies and might have caused malnutrition by blocking their midgut and decreasing food absorption. Hence, false significant or non-significant results were acquired instead.   Further studies are required using a much lower probiotic dosage if Drosophila is used as a disease model. Although, other models such as mice or rats are recommended in this case, in order to reach a solid conclusion about the effectiveness of probiotics in treating type 2 diabetes mellitus. Baring these thoughts in mind and based on the results of this experiment, the null hypothesis indicating that there is no significant relationship between the use of probiotics and reversing type 2 diabetes mellitus symptoms is therefore accepted.
253

Are mixed-breed dogs healthier than purebred dogs? A review of the current data on diseases and longevity in dogs.

Kristensen, Signe Frost January 2020 (has links)
In today’s world, more than 400 different dog breeds have been registered and the number continues to increase, as people come up with new ways of breeding dogs. Purebred dogs are prone to many inherited disorders, inbreeding depression and a decreasing gene pool. Mixed-breed dogs, on the other hand, are said to be less prone to these problems, as they have a higher genetic variation. This review combined knowledge from the last 25 years of research in the field of mixed-breed dogs and purebred dogs to see what we know and what we still need to examine further. The literature all in all agrees that mixed-breed dogs have an increased longevity, although other factors determine longevity other than breed. They also have a decreased risk of some of the major diseases such as organ disorders and cancer but are instead prone to other problems such as ruptured cranial cruciate ligament, behavioural problems such as aggression, accidents and diabetes. Future research needs to take the inverse relationship of body mass and longevity into account when measuring longevity between breeds and more studies should be made in the field of canine cancer, as this accounts for most deaths overall in dogs. / I dagens värld har mer än 400 olika hundraser registrerats och antalet fortsätter att öka gradvis, eftersom människor kommer med nya sätt att avla hundar. Renrasiga hundar kan ha stora problem med ett flertal ärftliga störningar, inavelsdepression och en minskande gen pool. Å andra sidan sägs hundar med blandad ras vara mindre benägna för dessa problem, eftersom de har en högre genetisk variation. Denna översyn sammanfattar kunskap från de senaste 25 årens forskning inom området blandade hundar och renrasiga hundar för att se vad vi vet och vad vi fortfarande behöver undersöka ytterligare. Litteraturen är överens om att hundar med blandad ras har en ökad livslängd, även om andra faktorer avgör livslängder än rasen. De har också en minskad risk för några av de huvudsakliga sjukdomarna som organ defekter och cancer, dock kan de ha andra problem såsom brustet kranialkorsband, beteendeproblem som aggression, olyckor och diabetes, vilket påverkar livslängden. Framtida forskning måste ta hänsyn till det omvända förhållandet mellan kroppsmassa och livslängd vid mätning av livslängd mellan raser. Fler studier bör göras inom området cancer hos hundar, eftersom detta står för de flesta dödsfall totalt sett hos hundar.
254

Effect of the acidic buffer 2-(N-Morpholino) ethanesulfonic acid on frozen-thawed bull semen

Botha, Alma Ester 25 February 2010 (has links)
The aim of the current study was to determine if frozen-thawed bull semen can be treated with the acidic buffer MES (2-[N- morpholino] ethanesulfonic acid) without any detrimental effect on the motility, plasma membrane, acrosomal membrane and longevity of sperm. Frozen bull semen was obtained from a local co-operative. The semen was frozen in 0.25 mL French straws at a concentration of 80 x 106 sperm cells per millilitre. Semen of two different batches from ten bulls of four different breeds was used in this study. Three frozen semen straws of each batch were thawed at 38° C for 25 seconds. The thawed semen was pooled and then split into two aliquots. The one aliquot was used as control, whilst the other was exposed to MES treatment. The motility, plasma membrane integrity, acrosomal membrane integrity and longevity of sperm were evaluated. The effect of MES on motility was minimal as only the percentage of aberrantly motile sperm increased two hours after treatment. Although no effect on the plasma membranes were observed, it can be assumed that some damage did occur due to the fact that the acrosomal membranes were affected significantly. No significant effect was found for longevity of sperm between the control and treated samples, but a significant effect was found for both the control and treated samples over time. Although the detrimental effects caused by MES treatment would render some sperm unable to fertilise an oocyte, it is likely that a sufficient portion of sperm would survive the treatment. It is probable that this treatment would also be effective in frozen-thawed buffalo semen. The following step would be to treat semen of footand-mouth disease positive bulls with MES to establish if treatment with MES will be effective in inactivating foot-and-mouth disease virus in semen of infected bulls. Copyright / Dissertation (MSc (Veterinary Science))--University of Pretoria, 2008. / Production Animal Studies / unrestricted
255

Membrane and Device Strategies for Improving the Detection limit and Longevity of Electrochemical Aptamer-based Sensors in Real Biofluids

Yuan, Yuchan 24 May 2022 (has links)
No description available.
256

Modeling the Longevity of Infiltration System for Phosphorus Removal.

Yu, Lin January 2011 (has links)
A new modeling method for estimation of the longevity of infiltration system was suggested in this study. The model was one-dimensional, based on results from long-term infiltration sites in Sweden, taking some physical and chemical parameters as controlling factors. It defines the longevity of infiltration systems as the time during which the P solution in effulent is under national criteria (1 mg/L in this study), and it aims at providing the longevity for any given point of the infiltration system. The soil in the model was assumed to be totally homogenous and isotropic and water flow was assumed to be unsaturated flow and constant continuous inflow. The flow rate was calculated from the Swedish criteria for infiltration systems. The dominant process in the model would be the solute transport process; however, retardation controlled by sorption would play a more important role than advection and dispersion in determining the longevity in the model. By using the definition of longevity in this study, the longevity of the three soil columns at 1 m depth (Knivingaryd, Ringamåla and Luvehult) were 1703 days, 1674 days and 2575 days. The exhaustion time of the three soil columns under inflow of 5 mg/L were 2531 days, 2709 days and 3673 days. The calculated sorbed phosphorus quantity for soil from sites Kn, Lu and Ri when they reach estimated longevity were 0.177, 0.288 and 0.168 mg/g, while the maximum sorption of Kn, Lu and Ri were 0.182, 0.293 and 0.176 mg/g separately. From the result of sensitivity study of the model, the sorption capacity and flow velocity were most important to the longevity of the infiltration system. Lower flow velocity and higher P sorption capacity extend the longevity of an infiltration bed. Due to the sorption isotherm selected in this study and the assumption of instant equilibrium, the sorption rate of the soil column was quite linear, although the estimated longevity was much shorter than the real exhaustion time of the soil column. In fact the soil has almost reached its sorption maximum when the system reaches its longevity.
257

How FIFA Scores from an Offside Position: Understanding the longevity of a Disliked Brand.

Bertholet, Joris, Juistenga, Daan January 2021 (has links)
Background: Organizations desire to create and maintain a strong and long-lasting relationship with their consumers. Firms enjoy many benefits through the loyalty of customers, such as lower marketing costs, increased revenue, and much more. Our study pinpoints two specific elements within brand loyalty that are in need of research: brand longevity, which describes the duration of a brand’s activeness, and customer loyalty to disliked brands. Furthermore, our study tries to identify how consumers add value during their relationship with the video game franchise FIFA. We identified the video game franchise FIFA as a perfect fit for this study; a criticized franchise that has been successful since 1993. Research Purpose: The purpose of this research is to understand why a disliked brand stays successful despite increasing criticisms from critics and consumers. Research Problem: Our study identified a need for further investigation into the concept of brand longevity, brands with a rich heritage would benefit from understanding their assemblage. Furthermore, qualitative research is needed to address the lack of knowledge of loyalty for disliked brands in other cultural and demographical contexts. Finally, more insights about customer value are needed to better understand how firms can evaluate their customers. Research Question: How is FIFA able to attain such longevity, despite receiving strong critics on their annual products? Method: Ontology through a relativistic scope - Epistemology with a social constructionism view - 20 Semi-structured Interviews - Snowball Sampling for gathering participants - Content Analysis for analyzing and coding the data. Conclusion: Our study managed to identify several drivers that keep consumers loyal to FIFA. We also identified how the community of FIFA perceives the environment of the franchise. Finally, the intensity of the value contribution has been outlined to illustrate how consumer differs from each other. Practical Implications: Emerging from our findings, implications are formulated for franchises, brands, and firms in general, both inside and outside of the gaming industry.
258

Factors Affecting the Longevity of the Department of Industrial Technology and Education at Utah State University 1985-2005: A Case Study

Cloward, Jerry 01 May 2009 (has links)
A qualitative case study method was used to discover the factors involved with the longevity of the Technology Education program at Utah State University. The problem was that while there were studies reporting the many Technology Education programs that have been closed there had been no studies on individual programs that have remained open. This study also contains a consolidation of relative information on the program. The primary data was obtained from interviews with the professors involved with the program during the timeframe of the study. The data obtained from the interviews was evaluated and set into themes. The factors were derived from the themes. The many factors presented in this study are evidence of the need to do this holistic study of the problem. The findings from this study provide a basis for study of other successful Technology Education programs.
259

The Lived Experiences of Couples in Long-Term Marriages in which One Partner was a Vietnam Veteran and is Diagnosed with PTSD

Richardson, Rozetia 01 January 2018 (has links)
Many couples get married hoping and believing their new relational commitment will last a lifetime. Unfortunately, however, this expectation sometimes goes unrealized. In our society, divorce rates are high and continue to climb due to a myriad of contributing factors. In regard to marriages directly connected to military culture and traditions, they not only grapple with managing the everyday stress and strain encapsulated in daily living, they also contend with military-related stressors that can also disrupt personal connections and derail marriages. In this study, the researcher will focus on the lived experience of Vietnam Combat Veteran Couples in long-term marriages diagnosed with PTSD. The goal of this study is to pinpoint some of the most-enduring yet integral aspects of intimacy having contributed to the long-term marriages of this population. The most-enduring and integral aspects within these relationships, in this population, has not been thoroughly studied. Moreover, this study will help to fill this gap in research by exploring the positive aspects found within the long-term marital relationships of Vietnam Combat Veteran Couples diagnosed with PTSD. The researcher will utilize a theoretical approach designed to work in concert with the multifaceted variances found within the premise of marriage itself; while also focusing on both the academic and practical sides of this phenomenon. The researcher will employ theme based interview questions in an attempt to examine the lived experience, as well as, the enduring and integral aspects associated with the longevity of these long-term marriages. Couple participants will be studied using the phenomenological method Interpretative Phenomenological Analysis (IPA). The results of which will guide the researcher in formulating discussions, conclusions, and recommendations for the future.
260

Comparisons of Five DNA Repair Pathways Between Elasmobranch Fishes and Humans

Llorente, Lucia 04 January 2019 (has links)
Although DNA repair capacity has been correlated with lifespan in terrestrial vertebrate species, it remains unknown how evolutionarily conserved the process is across all vertebrate taxa. In particular, chondrichthyan fishes have lifespans that range from 3-350 years and they are evolutionarily separated from modern humans Homo sapiens by approximately 400 million years. We hypothesized that chondrichthyan fishes would show significant homology in nuclear excision repair (NER) genes with humans, and that the expression of NER genes will correlate with the lifespan of the respective assessed species. For this study, DNA repair gene homology and expression was performed on the nurse shark Ginglymostoma cirratum (n=3) and yellow stingray Urobatis jamaicensis (n=3). The five main NER pathways were analyzed and compared to see the differences in both elasmobranch species, then compared with human foreskin fibroblast samples (n=3). RNA sequencing was used to determine the extent of gene expression in each species, comparing the read counts in each gene and comparing between the two species. The elephant shark Callorhinchus milii reference genome was used to align the nurse shark and yellow stingray samples. Homology of each gene of the NER pathways was assessed by the NCBI BLAST software. Results show that the MMR pathway has all the significant genes in higher frequencies in the nurse shark than in human. Within elasmobranchs in the five DNA repair pathways, the longer-lived species (nurse shark) has a significant higher gene expression than shorter-lived species (yellow stingray). Genes involved in the NER and BER pathways showed significantly lower expression in elasmobranch than in humans. However, there were significantly higher expression of more genes for the HR and MMR pathways in elasmobranchs than in humans.

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