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  • 1
    Online Resource
    Online Resource
    Springer Science and Business Media LLC ; 2019
    In:  Scientific Reports Vol. 9, No. 1 ( 2019-10-28)
    In: Scientific Reports, Springer Science and Business Media LLC, Vol. 9, No. 1 ( 2019-10-28)
    Abstract: The obligate dependency of the common hippopotamus, Hippopotamus amphibius , on water makes them particularly vulnerable to hydrological disturbances. Despite the threats facing this at-risk species, there is a lack of information regarding H. amphibius spatial ecology. We used high-resolution tracking data of male H. amphibius to assess home range size, movement mode (e.g. residency and migratory movements), and resource selection patterns. We compared these results across seasons to understand how hydrological variability influences H. amphibius movement. Our study watershed has been severely impacted by anthropogenic water abstraction causing the river to stop flowing for prolonged periods. We observed H. amphibius movements to be highly constrained to the river course with grassy floodplains being their preferred habitat. Dominant and small sub-adult males displayed year-round residency in/near river pools and had smaller home ranges compared to large sub-adults. During the dry season, large sub-adult males made significant (~15 km) upstream movements. The larger home range size of large sub-adults can be attributed to the elevated levels of migratory and exploratory activities to limit conspecific aggression as the river dries. Our observations provide insight into how future changes in water flow may influence male H. amphibius movements and populations through density-dependent effects.
    Type of Medium: Online Resource
    ISSN: 2045-2322
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2019
    detail.hit.zdb_id: 2615211-3
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  • 2
    Online Resource
    Online Resource
    Proceedings of the National Academy of Sciences ; 2018
    In:  Proceedings of the National Academy of Sciences Vol. 115, No. 22 ( 2018-05-29)
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 115, No. 22 ( 2018-05-29)
    Abstract: Cross-boundary transfers of nutrients can profoundly shape the ecology of recipient systems. The common hippopotamus, Hippopotamus amphibius , is a significant vector of such subsidies from terrestrial to river ecosystems. We compared river pools with high and low densities of H. amphibius to determine how H. amphibius subsidies shape the chemistry and ecology of aquatic communities. Our study watershed, like many in sub-Saharan Africa, has been severely impacted by anthropogenic water abstraction reducing dry-season flow to zero. We conducted observations for multiple years over wet and dry seasons to identify how hydrological variability influences the impacts of H. amphibius . During the wet season, when the river was flowing, we detected no differences in water chemistry and nutrient parameters between pools with high and low densities of H. amphibius . Likewise, the diversity and abundance of fish and aquatic insect communities were indistinguishable. During the dry season, however, high-density H. amphibiu s pools differed drastically in almost all measured attributes of water chemistry and exhibited depressed fish and insect diversity and fish abundance compared with low-density H. amphibius pools. Scaled up to the entire watershed, we estimate that H. amphibius in this hydrologically altered watershed reduces dry-season fish abundance and indices of gamma-level diversity by 41% and 16%, respectively, but appears to promote aquatic invertebrate diversity. Widespread human-driven shifts in hydrology appear to redefine the role of H. amphibius , altering their influence on ecosystem diversity and functioning in a fashion that may be more severe than presently appreciated.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    RVK:
    RVK:
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2018
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    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
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  • 3
    In: Anatomy Journal of Africa, African Journals Online (AJOL), Vol. 11, No. 2 ( 2022-12-08), p. 2240-2251
    Abstract: Early cardiac development is governed by transcription factor genes. TBX5, a T-box transcription factor gene, plays an important role in the development  of the second heart field during cardiac septation by promoting cell cycle progression through the enhancement of Cdk6 and hedgehog signaling  pathways. TBX5 binds to the promoter region of genes, enhancing the expression of alpha cardiac myosin heavy chain 6 (MYH6), which is a predominant  isoform found in human cardiac tissue. TBX5 gene mutations are postulated to cause congenital heart diseases. A casecontrol TBX5 mutational analysis  was performed to provide insight into the etiology of sporadic congenital heart diseases in our setting. We used a magnetic induction cycler (mic-PCR),  which is a next-generation tool for polymerase chain reaction-high resolution melting assays, to detect mutations in children with sporadic isolated  congenital heart diseases. A retrospective casecontrol study was conducted at the Jakaya Kikwete Cardiac Institute. The peripheral blood samples were  collected, and DNA was extracted using the Quick-DNA Miniprep Kit. The primers were designed using Primer 3 software, validated using the program  BLAST, and checked for hairpin and homo-hetero-dimerization using the IDT oligo analyzer. Real-time polymerase chain reaction (PCR)-high-resolution  melting assays for screening TBX5 gene mutations were done using a magnetic induction cycler. We found two (2) TBX5 mutations in exon 5, among  patients with Atrial-Ventral Septal Defects (ASVD) and Atrial-Septal Defects (ASD) and none among controls. TBX5 exon 5 is a molecular hotspot for  isolated congenital heart diseases. 
    Type of Medium: Online Resource
    ISSN: 2305-9478 , 2226-6054
    Language: Unknown
    Publisher: African Journals Online (AJOL)
    Publication Date: 2022
    detail.hit.zdb_id: 2868036-4
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  • 4
    Online Resource
    Online Resource
    Wiley ; 2011
    In:  Diversity and Distributions Vol. 17, No. 4 ( 2011-07), p. 603-612
    In: Diversity and Distributions, Wiley, Vol. 17, No. 4 ( 2011-07), p. 603-612
    Abstract: Aim  Large, charismatic and wide‐ranging animals are often employed as focal species for prioritizing landscape linkages in threatened ecosystems (i.e. ‘connectivity conservation’), but there have been few efforts to assess empirically whether focal species co‐occur with other species of conservation interest within potential linkages. We evaluated whether the African elephant ( Loxodonta africana ), a world‐recognized flagship species, would serve as an appropriate focal species for other large mammals in a potential linkage between two major protected area complexes. Location  A 15,400 km 2 area between the Ruaha and Selous ecosystems in central Tanzania, East Africa. Methods  We used walking transects to assess habitat, human activity and co‐occurrence of elephants and 48 other large mammal species ( 〉  1 kg) at 63 sites using animal sign and direct sightings. We repeated a subset of transects to estimate species detectability using occupancy modelling. We used logistic regression and AIC model selection to characterize patterns of elephant occurrence and assessed correlation of elephant presence with richness of large mammals and subgroups. We considered other possible focal species, compared habitat‐based linear regression models of large mammal richness and used circuit theory to examine potential connectivity spatially. Results  Elephants were detected in many locations across the potential linkage. Elephant presence was highly positively correlated with the richness of large mammals, as well as ungulates, carnivores, large carnivores and species 〉  45 kg in body mass (‘megafauna’). Outside of protected areas, both mammal richness and elephant presence were negatively correlated with human population density and distance from water. Only one other potential focal species was more strongly correlated with species richness than elephants, but detectability was highest for elephants. Main conclusions  Although African elephants have dispersal abilities that exceed most other terrestrial mammals, conserving elephant movement corridors may effectively preserve habitat and potential landscape linkages for other large mammal species among Tanzanian reserves.
    Type of Medium: Online Resource
    ISSN: 1366-9516 , 1472-4642
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2011
    detail.hit.zdb_id: 2020139-4
    detail.hit.zdb_id: 1443181-6
    SSG: 12
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  • 5
    Online Resource
    Online Resource
    Springer Science and Business Media LLC ; 2013
    In:  Conservation Genetics Resources Vol. 5, No. 1 ( 2013-3), p. 85-87
    In: Conservation Genetics Resources, Springer Science and Business Media LLC, Vol. 5, No. 1 ( 2013-3), p. 85-87
    Type of Medium: Online Resource
    ISSN: 1877-7252 , 1877-7260
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2013
    detail.hit.zdb_id: 2508018-0
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  • 6
    In: Molecular Ecology, Wiley, Vol. 22, No. 6 ( 2013-03), p. 1574-1588
    Type of Medium: Online Resource
    ISSN: 0962-1083
    RVK:
    Language: English
    Publisher: Wiley
    Publication Date: 2013
    detail.hit.zdb_id: 2020749-9
    detail.hit.zdb_id: 1126687-9
    SSG: 12
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  • 7
    In: Malaria Journal, Springer Science and Business Media LLC, Vol. 5, No. 1 ( 2006-12)
    Type of Medium: Online Resource
    ISSN: 1475-2875
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2006
    detail.hit.zdb_id: 2091229-8
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  • 8
    In: The Nucleus, Springer Science and Business Media LLC, Vol. 66, No. 1 ( 2023-04), p. 11-30
    Type of Medium: Online Resource
    ISSN: 0029-568X , 0976-7975
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
    detail.hit.zdb_id: 2589081-5
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  • 9
    In: Ecosphere, Wiley, Vol. 12, No. 6 ( 2021-06)
    Abstract: Globally, anthrax outbreaks pose a serious threat to people, livestock, and wildlife. Furthermore, environmental change can exacerbate these outbreak dynamics by altering the host–pathogen relationship. However, little is known about how the quantitative spatial dynamics of host movement and environmental change may affect the spread of Bacillus anthracis , the causative agent of anthrax. Here, we use real‐time observations and high‐resolution tracking data from a population of common hippopotamus ( Hippopotamus amphibius ) in Tanzania to explore the relationship between river hydrology, H. amphibius movement, and the spatiotemporal dynamics of an active anthrax outbreak. We found that extreme river drying, a consequence of anthropogenic disturbances to our study river, indirectly facilitated the spread of B. anthracis by modulating H. amphibius movements. Our findings reveal that anthrax spread upstream in the Great Ruaha River (~3.5 km over a 9‐day period), which followed the movement patterns of infected H. amphibius , who moved upstream as the river dried in search of remaining aquatic refugia. These upstream movements can result in large aggregations of H. amphibius . However, despite these aggregations, the density of H. amphibius in river pools did not influence the number of B. anthracis ‐induced mortalities. Moreover, infection by B. anthracis did not appear to influence H. amphibius movement behaviors, which suggests that infected individuals can vector B. anthracis over large distances right up until their death. Finally, we show that contact rates between H. amphibius‐ and B. anthracis‐ infected river pools are highly variable and the frequency and duration of contacts could potentially increase the probability of mortality. While difficult to obtain, the quantitative insights that we gathered during a real‐time anthrax outbreak are critical to better understand, predict, and manage future outbreaks.
    Type of Medium: Online Resource
    ISSN: 2150-8925 , 2150-8925
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 2572257-8
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  • 10
    Online Resource
    Online Resource
    Proceedings of the National Academy of Sciences ; 2004
    In:  Proceedings of the National Academy of Sciences Vol. 101, No. 41 ( 2004-10-12), p. 14847-14852
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 101, No. 41 ( 2004-10-12), p. 14847-14852
    Abstract: Resurgence of illicit trade in African elephant ivory is placing the elephant at renewed risk. Regulation of this trade could be vastly improved by the ability to verify the geographic origin of tusks. We address this need by developing a combined genetic and statistical method to determine the origin of poached ivory. Our statistical approach exploits a smoothing method to estimate geographic-specific allele frequencies over the entire African elephants' range for 16 microsatellite loci, using 315 tissue and 84 scat samples from forest ( Loxodonta africana cyclotis ) and savannah ( Loxodonta africana africana ) elephants at 28 locations. These geographic-specific allele frequency estimates are used to infer the geographic origin of DNA samples, such as could be obtained from tusks of unknown origin. We demonstrate that our method alleviates several problems associated with standard assignment methods in this context, and the absolute accuracy of our method is high. Continent-wide, 50% of samples were located within 500 km, and 80% within 932 km of their actual place of origin. Accuracy varied by region (median accuracies: West Africa, 135 km; Central Savannah, 286 km; Central Forest, 411 km; South, 535 km; and East, 697 km). In some cases, allele frequencies vary considerably over small geographic regions, making much finer discriminations possible and suggesting that resolution could be further improved by collection of samples from locations not represented in our study.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
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    RVK:
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2004
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
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