3,011 research outputs found
Managing external threats to national parks in Canada\u27s western mountains (Alberta)
External threats to protected areas exist because the area encompassed by the legal boundaries of many protected areas is less than what is needed to maintain a minimum viable population of various animal species and some types of plant associations. While external stresses to parks are the result of a wide range of human activities, they threaten ecological integrity in two general ways: by contributing to habitat fragmentation, alienation and loss (HFAL), and/or undermining the long-term viability of transboundary animal populations. However, in comparison to internal threats, addressing external threats is considerably more complex since park managers have no legal authority on adjacent private and public lands. In response, Parks Canada has adopted ecosystem management (EM) as a means of managing external threats to national parks. In order to implement EM at the landscape level, cooperative management strategies, also known as partnerships, are a means by which park managers can collaborate with adjacent actors to address various external threats. To date, relatively little work has been done to identify how such partnerships can be initiated and maintained. This paucity of information can be primarily attributed to the fact that relations between park managers and adjacent landowners and agencies have historically been confrontational in nature with conservation interests being seen as antithetical to development interests and vice versa. This thesis examines several EM partnership initiatives for Banff National Park (BNP) and Waterton Lakes National Park (WLNP) both in the Rocky Mountain region of Alberta. An analysis of the initiatives reveals that in addition to formal obstacles pertaining to planning legislation for adjacent public and private lands, numerous informal obstacles influence the ability of Parks Canada to implement EM at the landscape level: the ambiguity of ecological research and knowledge; the diversity of interests at the landscape level; the downsizing and reorganization of Parks Canada; the impact of past multi-stakeholder initiatives; and rapidly changing social, economic and political conditions. In addition to emphasizing the importance of tailoring partnerships to a specific biophysical and socioeconomic context, this research argues for Parks Canada to see its role as a facilitator rather than as an implementor for EM. Since this transfers the responsibility of implementing EM on adjacent lands into the hands of local people, organizations and institutions, this may lead to greater acceptance of the concept, thus reducing the severity of external threats facing national parks
The Polytetrafluoroethylene (PTFE) Graft for Portacaval Interposition: An Experimental Observation
In an attempt to determine the efficacy of the polytetrafluoroethylene (PTFE) graft as a portacaval interposition shunt, 26 mongrel dogs were randomly selected to receive a side-to-side shunt with a 6 mm, 8 mm, or 10 mm PTFE graft after portal hypertension had been created by hepatic vein ligation. The dogs were clinically observed, and if they showed signs of graft occlusion, they were reexplored surgically. The 6 mm graft had a 0% patency rate; the 8 mm graft had a 28.6% patency rate; and the 10 mm graft had an 87.5% patency rate. Histological examinations revealed adequate incorporation of the graft, formation of an endothelial layer, and absence of a thick intimal layer. In this experimental model, the PTFE graft served as a satisfactory portacaval interposition shunt when the 10 mm graft was used
Vesuvianite From Pajsberg, Sweden, and the Role of Be In the Vesuvianite Structure
Vesuvianite from Pajsberg, Sweden contains about one atom of Mn, based on 50 cations per formula unit, and small amounts of Be, B, and As. Optical absorption analysis suggests that the Mn is predominantly or entirely trivalent. Crystal-structure analysis indicates that Mn is housed at the general octahedral site Y3, which exhibits only minor distortion from ideal octahedral symmetry. Arsenic is housed at Y2 and Z2, and the formula derived from electron microprobe and LA-ICP-MS analyses suggests minor substitution of Al for Si, also at Z2. Beryllium and B are at T1, between the edge-sharing trimers Y3Y2Y3, as is the case for B in the boron-dominant vesuvianite species wiluite. The total content at T1 is interpreted as 0.82Be, 0.34B, and 0.037Fe^(3+)
Helminth Infections Induce Tissue Tolerance Mitigating Immunopathology but Enhancing Microbial Pathogen Susceptibility
Helminths are ubiquitous and have chronically infected vertebrates throughout their evolution. As such helminths have likely exerted considerable selection pressure on our immune systems. The large size of multicellular helminths and their limited replicative capacity in the host necessarily elicits different host protective mechanisms than the immune response evoked by microbial pathogens such as bacteria, viruses and intracellular parasites. The cellular damage resulting from helminth migration through tissues is a major trigger of the type 2 and regulatory immune responses, which activates wound repair mechanisms that increases tissue tolerance to injury and resistance mechanisms that enhance resistance to further colonization with larval stages. While these wound healing and anti-inflammatory responses may be beneficial to the helminth infected host, they may also compromise the host's ability to mount protective immune responses to microbial pathogens. In this review we will first describe helminth-induced tolerance mechanisms that develop in specific organs including the lung and the intestine, and how adaptive immunity may contribute to these responses through differential activation of T cells in the secondary lymphoid organs. We will then integrate studies that have examined how the immune response is modulated in these specific tissues during coinfection of helminths with viruses, protozoa, and bacteria
Avirulent Strains of Toxoplasma Gondii Infect Macrophages by Active Invasion from the Phagosome
Unlike most intracellular pathogens that gain access into host cells through endocytic pathways, Toxoplasma gondii initiates infection at the cell surface by active penetration through a moving junction and subsequent formation of a parasitophorous vacuole. Here, we describe a noncanonical pathway for T. gondii infection of macrophages, in which parasites are initially internalized through phagocytosis, and then actively invade from within a phagosomal compartment to form a parasitophorous vacuole. This phagosome to vacuole invasion (PTVI) pathway may represent an intermediary link between the endocytic and the penetrative routes for host cell entry by intracellular pathogens. The PTVI pathway is preferentially used by avirulent strains of T. gondii and confers an infectious advantage over virulent strains for macrophage tropism
Addressing the water and sanitation needs of primary schools: experiences from East Africa
In East Africa, many national governments have adopted a policy of free universal primary education in
recognition of the importance of an educated population to support local poverty reduction efforts. Unfortunately,
not enough consideration has been paid to the important contribution of clean and healthy school
conditions towards better educational achievements. Water and sanitation in schools also have important
gender aspects; the absence or inadequacy of these basic services is a major disincentive for many girls to
attend school. WaterCan’s Clean Water for Schools Program, launched in 2005, has to date assisted more
than 10,000 students and teachers at primary schools in East Africa. Using a combination of posters and
PowerPoint presentations, WaterCan’s Program Director and representatives from local partner organizations
working in East Africa, will share their practical experience gained from programming in over 25
primary schools located in various rural and urban contexts in Ethiopia, Kenya and Uganda
Vacuolar and plasma membrane stripping and autophagic elimination of Toxoplasma gondii in primed effector macrophages
Apicomplexan protozoan pathogens avoid destruction and establish a replicative niche within host cells by forming a nonfusogenic parasitophorous vacuole (PV). Here we present evidence for lysosome-mediated degradation of Toxoplasma gondii after invasion of macrophages activated in vivo. Pathogen elimination was dependent on the interferon γ inducible-p47 GTPase, IGTP, required PI3K activity, and was preceded by PV membrane indentation, vesiculation, disruption, and, surprisingly, stripping of the parasite plasma membrane. Denuded parasites were enveloped in autophagosome-like vacuoles, which ultimately fused with lysosomes. These observations outline a series of mechanisms used by effector cells to redirect the fate of a classically nonfusogenic intracellular pathogen toward a path of immune elimination
Incremental cost-effectiveness analysis of gestational diabetes mellitus screening strategies in Singapore
10.1177/1010539515612908Asia-Pacific Journal of Public Health28115-25GUSTO (Growing up towards Healthy Outcomes
Ethnic differences in effects of maternal prepregnancy and pregnancy adiposity on offspring size and adiposity
10.1210/jc.2015-1728The Journal of Clinical Endocrinology & Metabolism100103641–3650GUSTO (Growing up towards Healthy Outcomes
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