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To achieve their conservation goals individuals, communities and organizations need to acquire a diversity of skills, knowledge and information (i.e. capacity). Despite current efforts to build and maintain appropriate levels of conservation capacity, it has been recognized that there will need to be a significant scaling-up of these activities in sub-Saharan Africa. This is because of the rapid increase in the number and extent of environmental problems in the region. We present a range of socio-economic contexts relevant to four key areas of African conservation capacity building: protected area management, community engagement, effective leadership, and professional e-learning. Under these core themes, 39 specific recommendations are presented. These were derived from multi-stakeholder workshop discussions at an international conference held in Nairobi, Kenya, in 2015. At the meeting 185 delegates (practitioners, scientists, community groups and government agencies) represented 105 organizations from 24 African nations and eight non-African nations. The 39 recommendations constituted six broad types of suggested action: (1) the development of new methods, (2) the provision of capacity building resources (e.g. information or data), (3) the communication of ideas or examples of successful initiatives, (4) the implementation of new research or gap analyses, (5) the establishment of new structures within and between organizations, and (6) the development of new partnerships. A number of cross-cutting issues also emerged from the discussions: the need for a greater sense of urgency in developing capacity building activities; the need to develop novel capacity building methodologies; and the need to move away from one-size-fits-all approaches.
A comparison has been mager between ice velocities that were measured by the radio-echo technique and by a survey method on the Devon Island ice cap, Arctic Canada (lat. 75° 23' N., long. 82° 23'W.). Results were 2.58±0.11 ma1 by radar and 2.17±0.20 m a–1 by survey. The discrepancy between the two measurements is within the limits of statistical significance, and the methods are consigerred to give comparable results.
The aim of this paper is to use a model office to examine the potential impact of AIDS on non-linked life assurance business in the UK.
The subject of AIDS continues to stimulate a large amount of research. The UK actuarial profession has been kept informed by the regular Bulletins [1-5] from the Institute of Actuaries AIDS Working Party (the “IAWP”). Using a model developed by A. D. Wilkie , the IAWP examined the possible spread of the infection amongst male homosexuals and produced tables of additional mortality. The most recent Bulletin (No. 4), published in March 1989, updated these projections in the light of new data, and we have based our investigations principally upon these more recent projections.
The term “superplasticity” is taken as meaning high-strain-rate-sensitivity flow when it is used in geological contexts involving predominantly compressive stress states. Such flow has been observed in calcite and olivine polycrystalline aggregates in laboratory tests and the mechanism deduced to be diffusion-controlled granular flow. From microstructural observations, similar deformation processes are inferred to have occurred in a number of geological situations. On the basis of extrapolation from experiment to geology, superplastic flow might be expected under some geological conditions in calcite and olivine rocks at grain sizes approaching the order of one millimetre, while there are indications that the grain size limit for quartzites may be rather smaller. However, the knowledge of superplasticity in most rocks is still very fragmentary, especially in regard to mechanisms where a fluid phase may be involved, as in porous rocks.
In 1965 Griggs and Blacic [1,2] proposed that there is a “hydrolytic weakening” process in quartz and silicates whereby the breaking of Si-O bonds, involved in the movement of dislocations, is facilitated by the presence of water. This proposal aimed to explain the observed dramatic weakening of quartz crystals when they are exposed to water in tests at high temperature, as well as the observed strong contrast in creep strength between dry natural quartz crystals and rapidly-grown synthetic quartz crystals containing traces of water. Such a “hydrolytic” process may also underlie the observed effects of water in accelerating other phenomena such as self-diffusion of oxygen in quartz, aluminium-silicon ordering in feldspars, slow crack propagation in silicates, and recrystallization in quartz. A review of this field is given in Reference 3.
An estimate of the benefits which would result from a ban on the sale of non-pasteurized milk in Scotland has been assessed by costing a recent outbreak of milk-borne salmonellosis in the Grampian Region.
The cost of such a ban would not exceed the benefits under any but the most severe assumptions about the values attached to intangible benefits
Between 1980–5, 224 outbreaks of salmonellosis associated with poultry-meat were reported in Scotland. In total 2245 persons were affected, 12 of whom died. Twenty-one salmonella serotypes were identified from those affected, while 33 serotypes were isolated from poultry during routine monitoring and disease investigation. Existing measures to prevent the spread of salmonellae within poultry flocks and processing plants are failing. It is suggested that irradiation of poultry-meat may be the only effective method of reducing the public health problem of poultry-borne salmonellosis.
Hosts in nature will often acquire infections by different helminth species over their lifetime. This presents the potential for new infections to be affected (particularly via the host immune response) by a host's history of previous con- or hetero-specific infection. Here we have used an experimental rat model to investigate the consequences of a history of primary infection with either Nippostrongylus brasiliensis, Strongyloides venezuelensis or S. ratti on the fitness of, and immunological response to, secondary infections of S. ratti. We found that a history of con-specific, but not hetero-specific, infection reduced the survivorship of S. ratti; the fecundity of S. ratti was not affected by a history of either con- or hetero-specific infections. We also found that a history of con-specific infection promoted Th2-type responses, as shown by increased concentrations of total IgE, S. ratti-specific IgG1, rat mast cell protease II (RMCPII), IL4 (but decreased concentrations of IFNγ) produced by mesenteric lymph node cells in response to S. ratti antigen. Additionally, S. ratti-specific IgG1 was positively related to the intensity of both primary and secondary infections of S. ratti. Hetero-specific primary infections were only observed to affect the concentration of total IgE and RMCPII. The overall conclusion of these experiments is that the major immunological effect acting against an infection is induced by the infection itself and that there is little effect of prior infections of the host.
Evidence is provided from a sediment core from saline Abraxas Lake, Vestfold Hills, that indicates that the lake existed through the Last Glacial Maximum. It can therefore be concluded that at least part of the Vestfold Hills also remained ice-free through the Last Glacial Maximum, or at most was covered by a thin, non-erosive cold-based ice sheet. The evidence for the continued existence of Abraxas Lake includes a 14C date that significantly predates the Last Glacial Maximum (though this cannot be considered direct proof of the existence of the lake prior to the Last Glacial Maximum); the presence of saline porewater throughout the core, including in compacted sediments deposited during the glacial period, which implies that the lake obtained its salt prior to any Holocene marine highstand; and the occurrence of marine-derived fauna from the onset of significant biological activity late in the Pleistocene. The occurrence of ice-free land in the Vestfold Hills and similar oases suggests that the margin of the polar ice cap did not reach far beyond its current position at the Last Glacial Maximum, at least in regions now occupied by these oases.
The physiological and immunological state of an animal can be influenced by current infections and infection history. Consequently, both ongoing and previous infections can affect host susceptibility to another parasite, the biology of the subsequent infection (e.g. infection length) and the impact of infection on host morbidity (pathology). In natural populations, most animals will be infected by a succession of different parasites throughout the course of their lives, with probably frequent concomitant infections. The relative timing of different infections experienced by a host (i.e. the sequence of infection events), and the effects on factors such as host susceptibility and host survival, can only be derived from longitudinal data on individual hosts. Here we review some of the evidence for the impact of co-infection on host susceptibility, infection biology and pathology focusing on insights obtained from both longitudinal studies in humans and experiments that explicitly consider the sequence of infection. We then consider the challenges posed by longitudinal infection data collected from natural populations of animals. We illustrate their usefulness using our data of microparasite infections associated with field vole (Microtus agrestis) populations to examine impacts on susceptibility and infection length. Our primary aim is to describe an analytical approach that can be used on such data to identify interactions among the parasites. The preliminary analyses presented here indicate both synergistic and antagonistic interactions between microparasites within this community and emphasise that such interactions could have significant impacts on host-parasite fitness and dynamics.
The Waipounamu Erosion Surface is a time-transgressive, nearly planar, wave-cut surface. It is not a peneplain. Formation of the Waipounamu Erosion Surface began in Late Cretaceous time following break-up of Gondwanaland, and continued until earliest Miocene time, during a 60 million year period of widespread tectonic quiescence, thermal subsidence and marine transgression. Sedimentary facies and geomorphological evidence suggest that the erosion surface may have eventually covered the New Zealand subcontinent (Zealandia). We can find no geological evidence to indicate that land areas were continuously present throughout the middle Cenozoic. Important implications of this conclusion are: (1) the New Zealand subcontinent was largely, or entirely, submerged and (2) New Zealand's present terrestrial fauna and flora evolved largely from fortuitous arrivals during the past 22 million years. Thus the modern terrestrial biota may not be descended from archaic ancestors residing on Zealandia when it broke away from Gondwanaland in the Cretaceous, since the terrestrial biota would have been extinguished if this landmass was submerged in Oligocene–Early Miocene time. We conclude that there is insufficient geological basis for assuming that land was continuously present in the New Zealand region through Oligocene to Early Miocene time, and we therefore contemplate the alternative possibility, complete submergence of Zealandia.
The relationship between plutonic and volcanic rocks is central to understanding the geochemical evolution of silicic magma systems, but it is clouded by ambiguities associated with unravelling the plutonic record. Here we report an integrated U–Pb, O and Lu–Hf isotope study of zircons from three putative granitic–volcanic rock pairs from the Lachlan Fold Belt, southeastern Australia, to explore the connection between the intrusive and extrusive realms. The data reveal contrasting petrogenetic scenarios for the S- and I-type pairs. The zircon Hf–O isotope systematics in an I-type dacite are very similar to those of their plutonic counterpart, supporting an essentially co-magmatic relationship between these units. The elevated δ18O of zircons in these I-type rocks confirm a significant supracrustal source component. The S-type volcanic rocks are not the simple erupted equivalents of the granites, although the extrusive and plutonic units can be related by open-system magmatic evolution. Zircons in the S-type rocks define covariant εHf–δ18O arrays that attest to mixing or assimilation processes between two components, one being the Ordovician metasedimentary country rocks, the other either an I-type magma or a mantle-derived magma. The data are consistent with models involving incremental melt extraction from relatively juvenile magmas undergoing open-system differentiation at depth, followed by crystal-liquid mixing upon emplacement in shallow magma reservoirs, or upon eruption. The latter juxtaposes crystals with markedly different petrogenetic histories and determines whole-rock geochemical and textural properties. This scenario can explain the puzzling decoupling between the bulk rock isotope and geochemical compositions commonly observed for granite suites.
The host immune response has profound effects on parasitic nematode infections. Here we have investigated how a range of infection parameters are affected by host immune responses and by their suppression and enhancement. The infection parameters considered were the number of parasitic females, their size, per capita fecundity and intestinal position. We found that in immunosuppressive treatments worms persist in the gut, sometimes with a greater per capita fecundity, maintain their size and have a more anterior gut position, compared with worms from control animals. In immunization treatments there are fewer worms in the gut, sometimes with a lower per capita fecundity and they are shorter and have a more posterior gut position, compared with worms from control animals. Worms from animals immunosuppressed by corticosteroid treatment reverse their changes in size and gut position. This description of these phenomena pave the way for a molecular biological analysis of how these changes in infection parameters are brought about by the host immune response.
The application of molecular techniques to population biology can be traced back to the origins of allozyme gel electrophoresis (Smithies 1955) and the invention of histochemical stains targeting specific enzymes (Hunter and Markert 1957). Initial surprise at the high level of variation revealed was rationalised by the understanding that much molecular variation must be selectively neutral (Kimura 1968; King and Jukes 1969), and making this assumption, molecular markers were applied to samples of anonymous individuals to quantify population-level processes such as inbreeding, differentiation and phylogeography (Avise 1994).
Alongside these population genetics studies, there was a series of detailed studies in which phenotypic and spatial data about the individuals sampled was also collected, and the enzyme kinetic properties of alleles were quantified, allowing tests of selective neutrality at specific allozyme loci. Examples of allozyme polymorphisms that appear to be under selection include phosphoglucomutase in Colias butterflies (Watt et al. 1983), leucine aminopeptidase in the mussel Mytilus edulis (Koehn and Hillbish 1987) and lactate dehydrogenase-B in the marine killifish Fundulus heteroclitus (Powers et al. 1983). Similarly, several studies demonstrated correlations between average allozyme heterozygosity and phenotypic measures, which might be due to overdominance (heterozygote advantage) at specific loci or inbreeding depression (Allendorf and Leary 1986; Ledig 1986; Mitton 1997).
Nematode infections are subject to density-dependent effects on their establishment, survivorship and fecundity within a host. These effects act to regulate and stabilize the size of nematode populations. Understanding how these density-dependent effects occur is important to guide the development of control strategies against parasitic nematodes and the diseases that they cause. These density-dependent effects have been hypothesized to result from intraspecific competition between parasites for limited resources or from the action of host immune responses. However, no specific evidence exists to distinguish between these two hypotheses. We find that in nematode (Strongyloides ratti) infections, density-dependent effects on parasite establishment, survivorship and fecundity are mediated by the host immune response. These density-dependent effects are only observed late in primary infections and no density-dependent effects are observed in infections in immuno-compromised animals. We find no evidence for intraspecific competition between parasites in experimental infections over a range of doses that encompasses all that is observed in natural infections. We conclude that density-dependent effects due to the immune response will act to regulate S. ratti infections before competition for space or nutrients within the host gut ever occurs.
The aim of the work was to explore the impact on general and psychological health of those with a proven bacterial gastrointestinal infection and to compare this with controls from whom no bacterial pathogen was identified. A case control study was conducted using an interviewer-administered questionnaire. Thirty-nine cases from whose faeces salmonella or campylobacter had been cultured were compared with matched controls. Reported gastrointestinal symptoms, general health and self-reported hygiene practices were compared. At the time of acute illness the General Household Questionnaire suggested similar levels of morbidity, though by follow up the controls were substantially more likely to be distressed. Cases were more likely to have changed their food preparation practices, to avoid certain eating places and to have been given advice about food preparation. In this small study a positive diagnosis of salmonella or campylobacter seems to have had a reassuring effect when compared with those for whom no diagnosis was made.
Neural mediation of the human cardiac response to isocapnic (IC)
steady-state hypoxaemia was investigated using coarse-graining spectral
analysis of heart rate variability (HRV). Six young adults were exposed
in random order to a hypoxia or control protocol, in supine and sitting
postures, while end-tidal PCO2 (PET,CO2) was clamped at resting
eucapnic levels. An initial 11 min period of euoxia (PET,O2 100 mmHg;
13.3 kPa) was followed by a 22 min exposure to hypoxia (PET,O2 55
mmHg; 7.3 kPa), or continued euoxia (control). Harmonic and fractal
powers of HRV were determined for the terminal 400 heart beats in
each time period. Ventilation was stimulated (P < 0.05) and cardiac
dynamics altered only by exposure to hypoxia. The cardiac interpulse
interval was shortened (P < 0.001) similarly during hypoxia in both
body positions. Vagally mediated high-frequency harmonic power (Ph)
of HRV was decreased by hypoxia only in the supine position, while the
fractal dimension, also linked to cardiac vagal control, was decreased in
the sitting position (P < 0.05). However, low-frequency harmonic power
(Pl) and the HRV indicator of sympathetic activity (Pl/Ph) were not
altered by hypoxia in either position. These results suggest that, in
humans, tachycardia induced by moderate IC hypoxaemia (arterial O2
saturation Sa,O2 85 %) was mediated by vagal withdrawal,
irrespective of body position and resting autonomic balance, while
associated changes in HRV were positionally dependent.
The distribution of genetic differentiation in a population of the parasitic nematode Strongyloides ratti divided between
rat hosts was determined. We applied population genetic theory to these data to determine the source of new infections.
We estimate the rate at which a rat acquires a new infection from (a) the existing subpopulation of parasites within that
rat (‘self-reinfection’) versus (b) the wider environment (‘immigration’). We find that the observed levels of genetic
diversity and differentiation in the study population are consistent with low to moderate rates of self-reinfection and
inconsistent with high rates of self-reinfection.