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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.
51

Pigmentação testicular e ciclo reprodutivo anual de Physalaemus cuvieri Fitzinger, 1826 em populações de biomas distintos

Moresco, Rafaela Maria [UNESP] 26 April 2013 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:30:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-04-26Bitstream added on 2014-06-13T19:01:02Z : No. of bitstreams: 1 moresco_rm_dr_sjrp_parcial.pdf: 106475 bytes, checksum: d09b090350ada960f17c7c2d58ad3eb2 (MD5) / A reprodução pode ser descrita como o conjunto de atributos fisiológ icos, morfológicos e comportamentais que permitem o sucesso de uma espécie através da máxima descendência sob condições ambientais específicas. Em anfíbios, além de sujeito a um controle hormonal, e considerando o aporte genético, o ciclo reprodutivo é também influenciado por fatores ambientais que determinam o ciclo ga metogênico ao longo de um ano. O presente trabalho teve como objetivo estimar a di versidade genética em duas populações de P. cuvieri pertencentes aos biomas de Mata Atlânti ca e do Cerrado com o marcador molecular ISSR ( Inter Simple Sequence Repeats ). Além disso, foi caracte rizado o ciclo reprodutivo destas populações, relacionando as variações morfológicas gonadais com os fatores climáticos precipitação, temperatura, umidade relativa do ar e velocidade do vento, através de uma Análise de Correspondência Canônica, bem como relacionar a quantidade de pigmentos presente nos testículos com os períodos pré-reprodutivo, reprodutivo e regenerativo através de ANOVA. Ta mbém se analisou em indivíduos de Eupemphix nattereri a relação entre a espermiogênese e a qua ntidade de pigmentação testicular. As populações de P. cuvieri pertencentes aos dois biomas re velaram índice de diferenciação genética (FST ) > 0.288, o que mostra que es tas duas populações são altamente diferenciadas geneticamente. Foram caracter izados 7 tipos celu lares representando o epitélio germinativo. A variância total ao longo do ciclo reprodutivo foi de 23 %, com os dois primeiros eixos responsáveis, respectivamente, por 68,7% e 10,2% da variância total acumulada na média ponderada dos tipos celula res com relação às 4 variáveis ambientais analisadas. O teste de permutação de Monte Carlo indicou que os tipos celulares e a... / Reproduction can be described as the set of physiological, mo rphological, and behavioural attributes that allow for the success of a species through maximum offspring under specific environmental conditions. In amphibians, as well as being under hormonal control, and in view of their genetic constitution, the reproductive cycle is also influenced by environmental factors that determine the ga metogenetic cycle throughout the year. The aim of this study was to characterize the reproductive cycle of Physalaemus cuvieri in populations from the Mata Atlântica region and the Ce rrado region, comparing the morphological gonad variations to the climatic factors of precipita tion, temperature, relative humidity and wind speed, through a Ca nonical Correspondence Analysis, as well as comparing the quantity of pigments presen t in the testis with the pre-reproductive, reproductive and regenerative periods usi ng the ANOVA, and estimating the genetic diversity between the populations of the two biomes with genetic markers ISSR ( Inter Simple Sequence Repeats). The relationship between spermatogenesis and the quantity of testicular pigmentation in individuals of Eupemphix nattereri has also been analyzed... (Complete abstract click electronic access below)
52

Degradação do herbicida diuron por bactérias isoladas de solos de cultura de cana-de-açúcar e avaliação da toxidade dos metabolitos gerados sobre peixes /

Silva, Pedro Lucas Bueno da January 2015 (has links)
Orientador: Eleni Gomes / Banca: Thiago Scremin Pereira / Banca: Marcio Luis Busi da Silva / Banca: Marcelo de Freitas Lima / Resumo: A intensificação da agricultura tem levado um aumento da utilização de pesticidas, o que pode carrear esses compostos e seus derivados do solo para ambientes aquáticos. Para minimizar a presença desses compostos xenobióticos no meio, tem se sugerido técnicas de biorremediação que utiliza a atividade de micro-organismos para eliminação ou redução desses poluentes. O ataque de compostos aromáticos e clorados por micro-organismos ou por suas enzimas livres no meio podem levar ao desejável processo de biodegradação, originando derivados quimicamente mais simples e menos tóxicos até a mineralização total do composto. O objetivo do trabalho foi estudar a degradação do diuron por cepas bacterianas previamente isoladas de solos de cultivo de cana-de-açúcar com histórico de aplicação desse herbicida, em fermentação submersa e em microcosmos e avaliar a toxicidade dos compostos derivados do diuron gerados pelo metabolismo microbiano. Todas as bactérias testadas foram capazes de degradá-lo quando cultivadas em meio líquido. Quando se utilizou sistemas de cultivo em solo acrescido de diuron (microcosmos) obteve-se até 50% do composto. Nos testes de toxicidade dos metabólitos do diuron sobre peixes foi utilizada a atividade enzimática da 7-etoxiresorufina-O-deetilase (EROD) e teste do cometa como referência. Foi observada uma inibição da atividade da EROD, possivelmente relacionada a uma inibição das isoenzimas... / Abstract: The intensification of agriculture has led an increase in the use of pesticides, which may carry these compounds and their derivatives from soil to aquatic environments. To minimize the presence of xenobiotics in the environment, it has been suggestes bioremediation techniques that use the activity of microorganisms to eliminate or reduce these pollutants. The attack of aromatic and chlorinated compounds by microorganisms or their enzymes free in the medium can lead to desirable biodegradation process, yielding chemically simpler and less toxic derivatives until the total mineralization of the compound. The aim of this work was to study the degradation of diurom by bacterial strains previously isolated from cane sugar cultivation of soils with application history of this herbicide in submerged fermentation and in microcosms and evaluate the toxicity of diuron derived from compounds generated by metabolism microbial. All bacteria tested were able to grow in the presence of diuron, but not all were able to degrade it when cultured in liquid medium. When used in a soil cultivation systems plus diuron (microcosms) afforded 50% compound. In the tests of toxicity of the metabolites of diuron was used fish the enzymatic activity of 7-O-etoxiresorufina deetilase (EROD) and comet assay as a reference. Was observed inhibition of EROD activity, possibly related to... / Mestre
53

Bayou To Bench And Back

January 2016 (has links)
During and following the Deepwater Horizon (DWH) accident in 2010, concerns about air and seafood quality were paramount. Though individual perceptions varied, many people in coastal communities in southeast Louisiana felt they had been exposed to oil- and dispersant-related compounds. We hypothesized that implementation of a Community-based Participatory Research (CBPR) project would promote a more transparent and mutually beneficial relationship between researchers and the community. We conducted both in-home and community-based assessments (n=198) in culturally diverse populations most impacted by the DWH event, including the Vietnamese in New Orleans East and the residents of the Bayou communities. Levels of volatile organic compounds (VOCs) in paired indoor/outdoor air samples and polycyclic aromatic hydrocarbons (PAHs) in seafood samples were determined with chemical analysis. Data were collected from multiple self-administered surveys regarding environmental awareness and impact of the DWH event, access to, and trusted sources of, information, perceptions about safety, and selected behavioral and socio-demographic variables. In an effort to enhance public understanding of the interconnectedness of their health with the Gulf ecosystem, we disseminated the information directly to the participants as well as the larger communities at risk. Through post-dissemination follow-up surveys, we explored the effectiveness of our environmental CBPR research strategy with our primary goals being to improve risk communication and promote informed decision-making among our coastal populations. / Jessi Howard
54

Cytochrome P450 activity and pollutant exposure in New Zealand native birds

Numata, Mihoko, n/a January 2006 (has links)
Birds are potentially vulnerable to the toxicity of certain environmental pollutants due to limited detoxification capabilities of their liver microsomal cytochrome P450 (CYP) enzymes. In wild birds, ethoxyresorufin O-deethylation (EROD) activity, a marker of CYP1A activity in mammals and domestic chickens, has been used as a biomarker of exposure to polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). The aim of the present study was to investigate hepatic CYP activity as an indication of detoxification capacity in New Zealand birds. In addition to the use of conventional in vitro CYP activity assays, the applicability of a noninvasive CYP activity assay was tested using caffeine as the in vivo substrate. The ontogeny of liver microsomal 3-hydroxylation of quinine, a marker of human CYP3A activity, was investigated in Adelie penguins (Pygoscelis adeliae) from Ross Island, Antarctica. The results indicate that chicks (2-4 weeks old) possess a CYP3A-like isoform(s) as active as but not identical to the CYP3A-like isoform(s) in adults. Total CYP content was low at 2 weeks of age and increased rapidly and linearly approaching adult levels by 4 weeks of age implying a rapid development of CYPs other than the CYP3A-like isoform(s). The main study was conducted on adult (and some post-fledging immature) birds of two native species, the herbivorous paradise shelduck (Tadorna variegata) and the omnivorous southern black-backed gull (Larus dominicanus). Birds were shot for liver collection at three sites in the South Island of New Zealand; West Coast, Lake Waipori and Dunedin landfill, in 2001-2002. The results indicate that shelducks posssess multiple CYP isoforms that independently catalyse EROD, p-nitrophenol hydroxylation (p-NP) and erythromycin demethylation (EMD), markers of mammalian CYP1A, CYP2E and CYP3A activity, respectively. In contrast, gulls appear to possess a single isoform catalysing both EROD and p-NP but possess no isoform capable of catalysing EMD. EROD activity was high in shelducks and gulls from the landfill site, although it was not significantly associated with liver concentrations of PCBs (0.079-6.2 and 8.2-310 ng/g in shelducks and gulls, respectively), PCDD/PCDFs, toxic equivalents (TEQs) and dichlorodiphenyldichloroethylene (DDE) (0.85-317 and 44-4800 ng/g in shelducks and gulls, respectively) in either species. In shelduck livers from the landfill site, EROD was positively associated with Pb concentration but negatively associated with Hg concentration. Assessment of PCB congener patterns based on concentration ratios of individual congeners to the reference congener, 2,2�,4,4�,5,5�-hexachlorobiphenyl (IUPAC #153), indicate that the metabolism of 2,4,4�-trichlorobiphenyl (PCB#28) and 2,4,4�,5-tetrachlorobiphenyl (PCB#74) is inducible in shelducks but not in gulls. Hepatic reduced glutathione (GSH) content was higher in gulls than in shelducks suggesting greater resistance to oxidative stress in gulls. The in vivo caffeine metabolism test as a noninvasive method to determine CYP1A activity in shelducks and gulls gave a positive outcome. The test was performed by administration of a single intraperitoneal dose of caffeine (1 mg/kg body weight) followed by blood collection at 2 and 4 h after caffeine administration for determination of the serum concentration ratio of the metabolite, paraxanthine, to caffeine (PX/CA) by HPLC. In both species, the PX/CA ratio was markedly increased by pretreatment with the model CYP1A inducer, β-naphthoflavone (BNF). BNF treatment also increased EROD activity determined after death (80-fold and 20-fold compared to controls in shelducks and gulls, respectively). However, sensitivity of the PX/CA ratio approach was lower in gulls than in shelducks due presumably to the formation of unidentified caffeine metabolites in gulls. Immunoblot analysis failed to reveal increased CYP protein levels caused by BNF treatment in shelducks and gulls due to poor cross-reactivity of avian proteins with polyclonal antibodies raised against mammalian CYPs. EROD activity was also determined in livers of the piscivorous yellow-eyed penguin (Megadyptes antipodes) (1 chick, 3 post-fledging immature, 1 adult) from Otago, South Island of New Zealand, and found to be below the limit of quantitation. The adult liver contained 18.5 ng/g of total PCBs suggesting that EROD in this species is insensitive to induction. Comparison of the PCB congener pattern based on [PCBx]/[PCB#153] between the penguin and its putative source of PCB exposure, New Zealand marine fish, indicates that CYPs in yellow-eyed penguins metabolise 2,2�,5,5�-tetrachlorobiphenyl (PCB#52) and 2,2�,4,5,5�-pentachlorobiphenyl (PCB#101) as in many other avian species. The findings of this study highlight substantial species differences in CYP activity in wild birds. Whether CYP expression in New Zealand birds is genetically distinct from birds in other parts of the world may warrant further investigation.
55

Biochemical characterisation of landfill leachate toxicity in fish

Linderoth, Maria January 2006 (has links)
<p>Deposition remains the most common form of waste disposal in many parts of the world. As a terminus of the products consumed in our society a landfill may contain virtually all sorts of man-made chemicals. Despite this, the harmfulness of landfill leachate has not been extensively evaluated in feral organisms in the environment. In a leachate-contaminated lake, Molnbyggen, in Sweden, our studies reported a low percent of sexually mature (SM) female perch (<i>Perca fluviatilis</i>) that had decreased plasma androgen levels, decreased brain aromatase activity, distinctive sores and fin erosion. The impairments were attributed to unidentified compound(s) present in the leachate. In one out of four other investigated leachate-contaminated lakes, the low percent of SM female perch had reduced plasma sex steroid levels and similar sores as perch in Molnbyggen. The biochemical mechanism causing the disorders was investigated in order to establish a connection between the impairments and possible causative compound(s). Plasma levels of progesterone and 17α-hydroxyprogesterone were unaffected. Ovarian 17,20-lyase activity was decreased while levels of biliary steroid conjugates and hepatic testosterone UDP-glucuronosyltransferase activity did not differ between exposed and reference SM fish. Furthermore, the decreased brain aromatase activity seems to be a secondary effect; possibly a result of low substrate availability. Altogether, this suggests a possible disruption in the synthesis of androgens, knowledge that could be used as a tool in biomarker-directed fractionation studies to pinpoint compound(s). Molnbyggen sediment extracts decreased the testosterone and estradiol concentrations in whole-body homogenates of zebrafish (<i>Danio rerio</i>) after a three week exposure period. This suggests that compound(s) with the potency to alter endocrine function are present in the sediment. Although the first steps have been taken towards identifying compound(s) responsible for this kind of reproductive impairments, they still remain unidentified. Measures have to be taken to identify harmful chemicals in our society, to reduce their number, and to minimise their uncontrolled dispersal.</p>
56

Social acceptance of antimalarial strategies in Uganda

Helldorff, Hedvig January 2008 (has links)
<p>According to the World Health Organization(WHO) the most efficient and cost-effective strategies in the global fight of malaria are the Indoor Residual Spraying (IRS) and the Insecticide Treated Nets ITNs). However, since the strategies include the use of synthetic insecticides, WHO reports that they sometimes meet opposition in the society. In a Global Malaria Programme report from 20061, WHO describes that concerns in the community regarding the safety of the IRS hinder its effective implementation. WHO states that the social acceptability of ITNs2 has to increase. This study aims at investigating if and where in the Ugandan society the antimalarial strategies meet opposition. The study analyzes whether authorities, non-governmental organizations and caretakers in one region in Uganda reject the antimalarial strategies recommended by WHO. The aim is further to investigate where focus should be put in order to meet the</p><p>opposition (if any) to current strategies and thus facilitate the implementation of the strategies. The methodology used is an empirical approach based on interviews with officials at authorities, representatives of non-governmental organizations (NGOs) and caretakers in the slum areas in Kawempe Division, which is an area highly exposed to malaria, in Uganda. The results show that the authorities and the NGOs in this study accept the current strategies but believe that they are not fully accepted by caretakers. Further, the authorities and the NGOs point out that current strategies, mainly IRS, meet great resistance among politicians and within the agricultural and environmental sector. Nevertheless, the majority of the caretakers in the interviews does accept the strategies and give other reasons for not having them implemented in their houses. Many of the households do not have the money neither to buy the ITNs nor to have the IRS implemented in their houses. Thus, this study implies that the opposition to the current strategies is not among authorities, NGOs or caretakers but in the political, environmental and agricultural</p><p>sphere. In order to fight malaria in the study area, WHO and stakeholders have to work with the change of attitudes among politicians and stakeholders within the environmental and agricultural sector in Uganda. They also have to provide poor households with ITNs or IRS for free, since lack of money is the reason for the studied group of caretakers not having the recommended strategies implemented in their houses.</p>
57

Biochemical characterisation of landfill leachate toxicity in fish

Linderoth, Maria January 2006 (has links)
Deposition remains the most common form of waste disposal in many parts of the world. As a terminus of the products consumed in our society a landfill may contain virtually all sorts of man-made chemicals. Despite this, the harmfulness of landfill leachate has not been extensively evaluated in feral organisms in the environment. In a leachate-contaminated lake, Molnbyggen, in Sweden, our studies reported a low percent of sexually mature (SM) female perch (Perca fluviatilis) that had decreased plasma androgen levels, decreased brain aromatase activity, distinctive sores and fin erosion. The impairments were attributed to unidentified compound(s) present in the leachate. In one out of four other investigated leachate-contaminated lakes, the low percent of SM female perch had reduced plasma sex steroid levels and similar sores as perch in Molnbyggen. The biochemical mechanism causing the disorders was investigated in order to establish a connection between the impairments and possible causative compound(s). Plasma levels of progesterone and 17α-hydroxyprogesterone were unaffected. Ovarian 17,20-lyase activity was decreased while levels of biliary steroid conjugates and hepatic testosterone UDP-glucuronosyltransferase activity did not differ between exposed and reference SM fish. Furthermore, the decreased brain aromatase activity seems to be a secondary effect; possibly a result of low substrate availability. Altogether, this suggests a possible disruption in the synthesis of androgens, knowledge that could be used as a tool in biomarker-directed fractionation studies to pinpoint compound(s). Molnbyggen sediment extracts decreased the testosterone and estradiol concentrations in whole-body homogenates of zebrafish (Danio rerio) after a three week exposure period. This suggests that compound(s) with the potency to alter endocrine function are present in the sediment. Although the first steps have been taken towards identifying compound(s) responsible for this kind of reproductive impairments, they still remain unidentified. Measures have to be taken to identify harmful chemicals in our society, to reduce their number, and to minimise their uncontrolled dispersal.
58

Social acceptance of antimalarial strategies in Uganda

Helldorff, Hedvig January 2008 (has links)
According to the World Health Organization(WHO) the most efficient and cost-effective strategies in the global fight of malaria are the Indoor Residual Spraying (IRS) and the Insecticide Treated Nets ITNs). However, since the strategies include the use of synthetic insecticides, WHO reports that they sometimes meet opposition in the society. In a Global Malaria Programme report from 20061, WHO describes that concerns in the community regarding the safety of the IRS hinder its effective implementation. WHO states that the social acceptability of ITNs2 has to increase. This study aims at investigating if and where in the Ugandan society the antimalarial strategies meet opposition. The study analyzes whether authorities, non-governmental organizations and caretakers in one region in Uganda reject the antimalarial strategies recommended by WHO. The aim is further to investigate where focus should be put in order to meet the opposition (if any) to current strategies and thus facilitate the implementation of the strategies. The methodology used is an empirical approach based on interviews with officials at authorities, representatives of non-governmental organizations (NGOs) and caretakers in the slum areas in Kawempe Division, which is an area highly exposed to malaria, in Uganda. The results show that the authorities and the NGOs in this study accept the current strategies but believe that they are not fully accepted by caretakers. Further, the authorities and the NGOs point out that current strategies, mainly IRS, meet great resistance among politicians and within the agricultural and environmental sector. Nevertheless, the majority of the caretakers in the interviews does accept the strategies and give other reasons for not having them implemented in their houses. Many of the households do not have the money neither to buy the ITNs nor to have the IRS implemented in their houses. Thus, this study implies that the opposition to the current strategies is not among authorities, NGOs or caretakers but in the political, environmental and agricultural sphere. In order to fight malaria in the study area, WHO and stakeholders have to work with the change of attitudes among politicians and stakeholders within the environmental and agricultural sector in Uganda. They also have to provide poor households with ITNs or IRS for free, since lack of money is the reason for the studied group of caretakers not having the recommended strategies implemented in their houses.
59

Kartlegging og evaluering av miljøstatus i vannforekomster nær Statoils sandoljeprosjekt i Leismer (Alberta, Canada). Videreutvikling og utesting av en ny type passiv prøvetaker for metaller i naturlig vann. / Mapping and evaluation of the environmetal status of surface waters near Statoils Oilsands Area in Leismer(Alberta, Canada). Further developing and testing of a new type of passive sample for metals

Isaksen, Marte Eik January 2012 (has links)
I denne oppgaven har det blitt utført en kartlegging og evaluering av miljøstatus i overflatevann rundt Statoils oljesandområde i Alberta, Canada. Det har blitt prøvetatt vann for oppløst og syreoppløst konsentrasjon av grunnstoff for analyse på ICP-MS. Det har blitt målt for viktige parametere som pH, SUVA254 og oppløst organisk karbon. Hensikten med denne undersøkelsen er å følge opp miljøundersøkelsen utført av masterstudent i 2010 som ble gjort for å etablere bakgrunnsinformasjon fra området før produksjonen ble igangsatt, for å se om produksjonen har ført til høyere konsentrasjoner av grunnstoff i området. Resultatene viser at det ikke er store endringer fra undersøkelsen i 2010 og at vannkvaliteten i Christina River generelt sett er god. De fleste konsentrasjonene av grunnstoff er under grenseverdiene som er oppgitt. Det har også blitt utført forsøk på en ny type passiv prøvetaker kalt Metrox. Denne er en fortsettelse av en oppgave fra 2009/2010 der det ble gjort innledende forsøk, med forskjellige typer elektroder. Hensikten i denne oppgave var å videre teste den ut på lab. Det ble store forsinkelser fra bedriften som laget Metrox og forsøkene ble derfor ikke startet før i februar. Testene viste at Metrox var for ustabil til å testes i felt på grunn av at det ble brukt toelektrodesystem.
60

The Effects of Macronutrient Enrichments (ammonium) on the Distribution of Four Bioactive Trace Metals (Cd, Mo, Ni, Cu) in Seawater and Planktonic Biomass.

Hunnestad, Annie Vera January 2012 (has links)
Environmental impacts of aquaculture can be widespread and serious, and one of the problems connected to this activity is the release of waste in the form of macronutrients. One important aspect is the potential of a shift in the available nitrogen form from nitrate to ammonium. This has the potential of causing harmful algal blooms, and changing the composition of pelagic microbial communities. Because trace metals are linked to enzymatic transformations of nitrogen it can be expected that a shift in the available nitrogen form to also change the cycling of trace metals in the water column and the microbial uptake. This work presented in this thesis has been part of the large collaborative WAFOW project, and was carried out at the Huinay Scientific Field Station in the Comau Fjord (Northern Patagonian region of Chile). The experiment was designed to follow changes in different variables as a gradient of ammonium was added to different bodies of water (mesocosms). Two types of water were studied (surface and ~10 m depth), and five treatments with increasing ammonium flux were carried out for each water type. In this thesis the variations in the distribution of four different trace metals (Cd, Mo, Ni and Cu) with an increasing ammonium flux has been studied. Samples were analyzed for chelex labile and DGT labile forms of the metals, as well for metal concentration in different size fractions of particles. The enrichment by ammonium caused a bloom in biomass, and caused changes in the distribution of all four metals studied. Most of the metals showed decreasing chelex labile and DGT labile concentration with rising ammonium concentration. For cadmium there was a marked increased uptake per g carbon up to a certain point of ammonium enrichment, and a marked decreased uptake per g carbon when very high amounts of ammonium were added. This suggests that the very high ammonium enrichment scenario somehow has had an inhibiting effect on phytoplankton cadmium uptake. For molybdenum there was a decreasing uptake per g carbon with increasing ammonium flux. This is probably caused by a decreased need for molybdenum in enzymatic transformations of nitrogen when ammonium is supplied in place of nitrate.

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