75 research outputs found

    ZrO2 Based materials as photocatalysts for 2-propanol oxidation by using UV and solar light irradiation and tests for CO2 reduction

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    Bare ZrO2, Ce doped ZrO2 and Er doped ZrO2 samples have been prepared by a hydrothermal process and have been used as photocatalysts for 2-propanol oxidation reaction in gas solid regime. Moreover, some preliminary tests have been carried out for CO2 reduction. The samples were physico-chemically characterized and both bare and doped ZrO2 based materials resulted active for oxidation and reduction reactions by using UV and solar irradiation. The reactivity results have been correlated with the compositional, structural and morphological features of the photocatalysts

    Mitochondrial DNA diversity and population structure of humpback whales from their wintering areas in the Indian and South Atlantic Oceans (Wintering Regions A,B, C and X). Scientific Committee document SC/56/SH3, International Whaling Commission, July 2004, Sorrento, Italy

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    Humpback whales in the Southern Hemisphere are separated by the International Whaling Commission (IWC) into seven wintering Regions (A-G) based on tropical distribution. To better evaluate the significance of these stock subdivisions, an analysis of mtDNA was conducted for the eastern and western South Atlantic (Regions A and B), the southwestern Indian Ocean (Region C) and the northern Indian Ocean (Region X). A total of 1,416 individual whales representing eleven sampling sites within the four wintering Regions were sequenced for a portion of the mtDNA control region. A hierarchical analysis of molecular variance (AMOVA) using FST and FST supported the division of wintering Regions based on IWC designated boundaries of A, B, C, and X. Pairwise comparisons further confirmed the A, B and C divisions, although varying degrees of heterogeneity (particularly molecular distances) were detected for proposed sub-divisions within Regions B and C. Overall, this large-scale mtDNA analysis for humpback whales in the Indian and South Atlantic Oceans supports wintering Region designations by the IWC. However, additional analyses and consideration of biological parameters such as gene flow are needed so that ‘within-region’ genetic analyses can help evaluate population structure and recovery in a management context

    The waters of São Tomé: a calving ground for West African humpback whales?

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    In the Southern Hemisphere, humpback whales Megaptera novaeangliae feed in Antarctic waters during the austral summer and migrate to their breeding grounds in subtropical and tropical waters during the winter. Historical whaling records suggest that the Archipelago of Sao Tome and Principe, located in the Gulf of Guinea, serves as a possible breeding ground. In order to investigate the temporal occurrence and group composition of humpback whales around Sao Tome Island, annual surveys were conducted during the breeding season between 2002 and 2006. A total of 186 boat-based surveys took place during this period. Data collected during each sighting included geographical positions, group size, group composition and behavioural classifications. Of the 66 groups encountered, mother/calf pairs made up a large proportion (65.15%), followed by solitary individuals (15.15%). Mother/calf pairs were seen in the region into November and resightings of identified animals indicate periods of occupancy that extended over three weeks. Few behaviours typically associated with mating activity were observed. Given the high percentage of mother/calf pairs, sometimes with very young calves, and the low frequency of mating activity, the waters of Sao Tome may primarily serve as a calving and nursing or resting area for humpback whales.Projecto Delfim; Rolas Island Resort; ECOFAC (Conservation et utilisation rationnelle des Ecosystemes Forestiers en Afrique Centrale); Wildlife Conservation Society

    Does temporal and spatial segregation explain the complex population structure of humpback whales on the coast of West Africa?

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    Humpback whales (Megaptera novaeangliae) in the Southeastern Atlantic Ocean (International Whaling Commission ‘Breeding Stock B’—BSB) are distributed from the Gulf of Guinea to Western South Africa. Genetic data suggest that this stock may be sub-structured, but it remains unknown if this is due to reproductive segregation. This paper evaluates the spatial and temporal population structure of BSB humpback whales using a combination of maternally and bi-parentally inherited markers. The genetic differentiation that we identify in this study could be due to a combination of (1) spatial and/or temporal segregation on breeding grounds in the greater Gulf of Guinea, (2) the possibility of maternally inherited site fidelity to specific feeding grounds and (3) the use of two generalized but exclusive migratory routes (coastal and offshore) between feeding and breeding areas. Further, photo-identification and genetic sampling efforts in other areas of the Sub-Saharan Western Africa winter range and targeted deployment of satellite tags would help to clarify some of the apparent complexity in the population structure of animals biopsied in this region.National Research Foundation (South Africa) under Grant Number 2053539. I. Carvalho was supported by a PhD scholarship (SFRH/BD/18049/2004), from the Portuguese Foundation for Science and Technology (Fundação para a Ciência e Tecnologia—FCT).http://link.springer.com/journal/227hb201

    Distinct genetic architectures and environmental factors associate with host response to the γ2-herpesvirus infections

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    Kaposi’s sarcoma-associated herpesvirus (KSHV) and Epstein-Barr Virus (EBV) establish life-long infections and are associated with malignancies. Striking geographic variation in incidence and the fact that virus alone is insufficient to cause disease, suggests other co-factors are involved. Here we present epidemiological analysis and genome-wide association study (GWAS) in 4365 individuals from an African population cohort, to assess the influence of host genetic and non-genetic factors on virus antibody responses. EBV/KSHV co-infection (OR = 5.71(1.58–7.12)), HIV positivity (OR = 2.22(1.32–3.73)) and living in a more rural area (OR = 1.38(1.01–1.89)) are strongly associated with immunogenicity. GWAS reveals associations with KSHV antibody response in the HLA-B/C region (p = 6.64 × 10−09). For EBV, associations are identified for VCA (rs71542439, p = 1.15 × 10−12). Human leucocyte antigen (HLA) and trans-ancestry fine-mapping substantiate that distinct variants in HLA-DQA1 (p = 5.24 × 10−44) are driving associations for EBNA-1 in Africa. This study highlights complex interactions between KSHV and EBV, in addition to distinct genetic architectures resulting in important differences in pathogenesis and transmission

    First circumglobal assessment of Southern Hemisphere humpback whale mitochondrial genetic variation and implications for management

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    The description of genetic population structure over a species\u27 geographic range can provide insights into its evolutionary history and also support effective management efforts. Assessments for globally distributed species are rare, however, requiring significant international coordination and collaboration. The global distribution of demographically discrete populations for the humpback whale Megaptera novaeangliae is not fully known, hampering the definition of appropriate management units. Here, we present the first circumglobal assessment of mito - chondrial genetic population structure across the species\u27 range in the Southern Hemisphere and Arabian Sea. We combine new and existing data from the mitochondrial (mt)DNA control region that resulted in a 311 bp consensus sequence of the mtDNA control region for 3009 individuals sampled across 14 breeding stocks and subpopulations currently recognized by the International Whaling Commission. We assess genetic diversity and test for genetic differentiation and also estimate the magnitude and directionality of historic matrilineal gene flow between putative populations. Our results indicate that maternally directed site fidelity drives significant genetic population structure between breeding stocks within ocean basins. However, patterns of connectivity differ across the circumpolar range, possibly as a result of differences in the extent of longitudinal movements on feeding areas. The number of population comparisons observed to be significantly differentiated were found to diminish at the subpopulation scale when nucleotide differences were examined, indicating that more complex processes underlie genetic structure at this scale. It is crucial that these complexities and uncertainties are afforded greater consideration in management and regulatory efforts

    Transit station or destination? Attendance patterns, movements, and abundance estimate of humpback whales off west South Africa from photographic and genotypic matching

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    Humpback whales found off west South Africa (WSA) are known to display an atypical migration that may include temporary residency and feeding during spring and summer. At a regional scale there is uncertainty about how these whales relate to the greater West African Breeding Stock B as a whole, with evidence both for and against its division into two sub-stocks. A database containing sighting information of humpback whales intercepted by boat in the WSA region from 1983 to 2008 was compiled. It included a total of 1,820 identification images of ventral tail flukes and lateral views of dorsal fins. After systematic within- and between-year matching of images of usable quality, it yielded 154 different individuals identified by tail flukes (TF), 230 by left dorsal fins (LDF), and 237 by right dorsal fins (RDF). Microsatellite (MS) matching of 216 skin biopsies yielded 156 individuals. By linking all possible sightings of the same individuals using all available identification features, the periodicity and seasonality of 281 individual whales were examined. Sixty whales were resighted on different days of which 44 were between different calendar years. The most resightings for one individual was 11 times, seen in six different years, while the longest interval between first and last sightings was about 18 years. A resighting rate of 15.6% of whales at intervals of a year or more indicates long-term fidelity to the region. Shorter intervals of 1 – 6 months between sequential sightings in the same year may suggest temporary residency. The TF image collection from WSA was compared to TF collections from four other regions, namely Gabon, Cabinda (Angola), Namibia and the Antarctic Humpback Whale Catalogue (AHWC). Three matches were detected were between WSA (in late spring or summer) and Gabon (in winter), confirming direct movement between these regions. The capture-recapture data of four different identification features (TF, RDF, LDF and MS) from six successive subsets of data from periods with the highest collection effort (2001 – 2007), were used to calculate the number of whales that utilise the region, using both closed and open-population models. Since dorsal fins have never been used to estimate abundance for humpback whales, the different identification features were evaluated for potential biases. This revealed 9 – 14% incidence of missed matches (false negatives) when using dorsal fins that will result in an overestimate, while variation in individual fluke-up behaviour may lower estimates due to heterogeneity of individual capture probability, by as much as 57-69%. Taking into consideration the small dataset and low number of recaptures, the most consistent and precise results were obtained from a fully time-dependent version of the Jolly-Seber open-population model, with annual survival fixed at 0.96, using the MS dataset. This suggests that the WSA feeding assemblage during the months of spring and summer of the study period numbered about 500. The relationship of these whales to those (perhaps strictly migratory) that may occur here in other seasons of the year, and their links to possible migratory routes and other feeding or breeding areas remain uncertain.National Research Foundation (NRF), South Africa, under Grant Number 2047517. Earthwatch Institute (funding), The Mazda Wildlife Fund (through the provision of a field vehicle), SASOL (through the donation of two four-stroke engines), PADI Project AWARE (UK) (funding), the South African Navy (access to the shore-based look-out), the Military Academy, University of Stellenbosch (accommodation) and Iziko South African Museum (office space and support). JB gratefully received financial support in the form of bursaries from the NRF, the Society for Marine Mammalogy, University of Pretoria, and the Wildlife Society of South Africa (Charles Astley Maberley Memorial bursary). The Namibian Dolphin Project is supported by NACOMA (Namibian Coastal Conservation and Management Project), the Nedbank Go Green Fund, Mohammed bin Zayed Species Conservation Fund, the British Ecological Society, the Rufford Small Grants Foundation and the Namibia Nature Foundation. JB and TJQC received funding from the International Whaling Commission (IWC) to conduct between-region matching.http://www.tandfonline.com/loi/tams20nf201

    Population Structure of Humpback Whales from Their Breeding Grounds in the South Atlantic and Indian Oceans

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    Although humpback whales are among the best-studied of the large whales, population boundaries in the Southern Hemisphere (SH) have remained largely untested. We assess population structure of SH humpback whales using 1,527 samples collected from whales at fourteen sampling sites within the Southwestern and Southeastern Atlantic, the Southwestern Indian Ocean, and Northern Indian Ocean (Breeding Stocks A, B, C and X, respectively). Evaluation of mtDNA population structure and migration rates was carried out under different statistical frameworks. Using all genetic evidence, the results suggest significant degrees of population structure between all ocean basins, with the Southwestern and Northern Indian Ocean most differentiated from each other. Effective migration rates were highest between the Southeastern Atlantic and the Southwestern Indian Ocean, followed by rates within the Southeastern Atlantic, and the lowest between the Southwestern and Northern Indian Ocean. At finer scales, very low gene flow was detected between the two neighbouring sub-regions in the Southeastern Atlantic, compared to high gene flow for whales within the Southwestern Indian Ocean. Our genetic results support the current management designations proposed by the International Whaling Commission of Breeding Stocks A, B, C, and X as four strongly structured populations. The population structure patterns found in this study are likely to have been influenced by a combination of long-term maternally directed fidelity of migratory destinations, along with other ecological and oceanographic features in the region

    A white humpback whale (Megaptera novaeangliae) in the Atlantic Ocean, Svalbard, Norway, August 2012

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    A white humpback whale (Megaptera novaeangliae) was observed on several occasions off Svalbard, Norway, during August 2012. The animal was completely white, except for a few small dark patches on the ventral side of its fluke. The baleen plates were light-coloured, but the animal's eyes had normal (dark) colouration. This latter characteristic indicates that the animal was not an albino; it was a leucistic individual. The animal was a full-sized adult and was engaged in “bubble-feeding”, together with 15–20 other humpback whales, each time it was seen. Subsequent to these sightings, polling of the marine mammal science community has resulted in the discovery of two other observations of white humpback whales in the Barents Sea area, one in 2004 and another in 2006; in both cases the observed individuals were adult animals. It is likely that all of these sightings are of the same individual, but there is no genetic or photographic evidence to confirm this suggestion. The rarity of observations of such white individuals suggests that they are born at very low frequencies or that the ontogenetic survival rates of the colour morph are low
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