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131.
Louise Bedsworth 《Climatic change》2012,111(1):119-133
A changing climate will exacerbate many of the problems currently faced by California’s public health institutions. The public
health impacts of climate change include: an increase in extreme heat events and associated increases in heat-related morbidity
and mortality, increases in the frequency and severity of air pollution episodes, shifts in the range and incidence of vector-borne
diseases, increases in the severity of wildfire, increased risks of drought and flooding, and other extreme events. This article
assesses the readiness of California’s public health institutions to cope with the changes that will accompany a changing
climate and how they relate to strategies laid out in the state’s Climate Adaptation Strategy. County-level health offices
are the front line actors to preserve public health in the face of numerous threats, including climate change. Survey results
show that local health officers in California believe that climate change is a serious threat to public health, but feel that
they lack the funding and resources to reduce this risk. Local health agencies also have a number of tools in place that will
be helpful for preparing for a changing climate. 相似文献
132.
Neil Cory Ishi Buffam Hjalmar Laudon Louise Bjrkvald Carl-Magnus Mrth Stephan Khler Kevin Bishop 《Applied Geochemistry》2009,24(9):1677-1685
The adverse impacts of the inorganic labile monomeric Al (Ali) fraction on aquatic organisms have meant that Al (Altot) determination and even speciation has become a routine part of environmental monitoring and assessment. However, if samples are not filtered prior to analysis then particulate Al (Altot(p)) could influence the determination of Altot, and therefore the determination of the more toxicologically important (Ali), both when it is measured analytically or modelled from Altot. This paper shows that the Al/DOC ratio in unfiltered samples can identify the Altot(p) fraction, and thus improve the speciation of Ali. These findings are based on data from a study in a 67 km2 catchment in northern Sweden during the snowmelt-driven spring flood of two consecutive years. Filtered and unfiltered samples were studied to determine the spatial and temporal patterns in Altot(p). The concentrations of Altot(p) were greatest in larger downstream sites where significant silt deposits are located. The sites with no silt in their drainage area showed a mean difference between filtered (Altot(f)) and unfiltered (Altot(uf)) samples of 6%, while sites with silt deposits had a mean difference of 65%. The difference between filtered and unfiltered samples was greatest at peak flow. Spikes in Altot(p) did not behave consistently during fractionation with a cation exchange column, resulting in increases in either measured Ali(f) or non-labile monomeric Al (Alo(f)). Altot(p) spikes were associated with sharp increases in the Al:DOC ratio. The baseflow Al:DOC ratio could be used to model filtered Altot from DOC with a Spearman rho of 0.75. 相似文献
133.
134.
The inclusion of new groups of workers has been an important component of union renewal efforts. Several unions in Canada have begun to dedicate significant resources to better organize and represent Aboriginal workers. Drawing on interviews with union activists, organizers and representatives from two national public sector unions in Canada, we present an overview of union strategies to engage with Aboriginal peoples. Results suggest that understanding the distinct territorial context of Aboriginal peoples’ relationships to work and unions has been necessary to the success of these union strategies. This approach begins by drawing connections between Aboriginal peoples’ present-day relationships to work and their prior occupancy of, and dispossession from, lands and resources. Because of the geographical specificity of how the colonial experience affected Aboriginal peoples’ relationships to work and unions, unions have had to adopt non-normative approaches to their engagements with Aboriginal peoples. In workplaces where settlers were dominant, addressing racism in the workplace and gaining support for initiatives to hire and train Aboriginal workers were important. Alternatively, in Aboriginal workplaces, organizing was a priority. Here questions of union legitimacy have taken precedence and the focus of unions has been on partnership building. Most importantly, however, engagement with Aboriginal peoples has brought attention to the colonial practices within unions and helped to foster growing Aboriginal voice within the labour movement. 相似文献
135.
Sediment connectivity: a framework for understanding sediment transfer at multiple scales 总被引:2,自引:0,他引:2
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A major challenge for geomorphologists is to scale up small‐magnitude processes to produce landscape form, yet existing approaches have been found to be severely limited. New ways to scale erosion and transfer of sediment are thus needed. This paper evaluates the concept of sediment connectivity as a framework for understanding processes involved in sediment transfer across multiple scales. We propose that the concept of sediment connectivity can be used to explain the connected transfer of sediment from a source to a sink in a catchment, and movement of sediment between different zones within a catchment: over hillslopes, between hillslopes and channels, and within channels. Using fluvial systems as an example we explore four scenarios of sediment connectivity which represent end‐members of behaviour from fully linked to fully unlinked hydrological and sediment connectivity. Sediment‐travel distance – when combined with an entrainment parameter reflecting the frequency–magnitude response of the system – maps onto these end‐members, providing a coherent conceptual model for the upscaling of erosion predictions. This conceptual model could be readily expanded to other process domains to provide a more comprehensive underpinning of landscape‐evolution models. Thus, further research on the controls and dynamics of travel distances under different modes of transport is fundamental. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
136.
Marie Weisfeiler Donald L. Turcotte Louise H. Kellogg 《Meteoritics & planetary science》2017,52(5):859-868
The early evolution of the asteroid Vesta has been extensively studied because of the availability of relevant data, especially important new studies of HED meteorites which originated from Vesta and the Dawn mission to Vesta in 2011–2012. These studies have concluded that an early melting episode led to the differentiation of Vesta into crust, mantle, and core. This melting episode is attributed to the decay of 26Al, which has a half‐life of 7.17 × 105 yr. This heating produced a global magma ocean. Surface cooling of this magma ocean will produce a solid crust. In this paper, we propose a convective heat‐transfer mechanism that effectively cools the asteroid when the degree of melting reaches about 50%. We propose that a cool solid surface crust, which is gravitationally unstable, will founder into the solid–liquid mix beneath and will very effectively transfer heat that prevents further melting of the interior. In this paper, we quantify this process. If Vesta had a very early formation, melting would commence at an age of about 1,30,000 yr, and solidification would occur at an age of about 10 Myr. If Vesta formed with a time delay greater than about 2 Myr, no melting would have occurred. An important result of our model is that the early melting episode is restricted to the first 10 Myr. This result is in good agreement with the radiometric ages of the HED meteorites. 相似文献
137.
R. Louise 《Astrophysics and Space Science》1982,86(2):505-508
The model is based on the assumption that logarithmic spiral arms of most spiral galaxies are due to the totating density wave
obeying the steady wave equation
. It is shown that this equation accounts also for the so-called Titius-Bode's law in the solar system. 相似文献
138.
Three southern planetary nebulae (NGC 2818, He 2-130, and NGC 3132) have been observed with the IDS (Image Dessector Scanner) combined with the Boller and Chivens spectrograph mounted at the Cassegrain focus of the 1.52 m telescope of the ESO in Chile. The spectrograph dispersion was 60 Å mm–1 in the spectral range 6170–7298 Å. The slit aperture was 4×4. Spectra were obtained from an array of positions across each nebula along the E-W direction and/or N-S direction. The data reduction followed the standard IHAP routines for IDS observations. In order to derive electron density, only the [Sii] lines (6617 Å–6731 Å) are given in this paper. The results are in agreement with a shell structure for the observed nebulae.
Toutes les observations ont été faites à l'Observatoire européen Austral (ESO) au Chili. 相似文献
Toutes les observations ont été faites à l'Observatoire européen Austral (ESO) au Chili. 相似文献
139.
The study of rotation curves is the most powerful tool for determining mass distributions inside spiral galaxies. Since the first trial by Burbidgeet al. (1959), followed by Brandt (1960), few methods have been proposed for the determination of the masses of galaxies (Faber and Gallagher, 1979). Monnet and Simien (1977) recently proposed a method based on a two component model (bulge and disk) which permits to compute the total mass providing that the photometry is well-known. We suggest here a method based on a new simple parametrization of the optical rotation curve. This method indicates disk masses substantially higher than the provious estimates and suggests an exponential increase of theM/L ratio in the disk toward the outer parts of the Galaxies. 相似文献
140.
Harry?L.?BrydenEmail author Lisa?M.?Beal Louise?M.?Duncan 《Journal of Oceanography》2005,61(3):479-492
Using a year-long moored array of current meters and well-sampled synoptic sections, we define the variability and mean structure and transport of the Agulhas current. Nineteen current meter records indicate that time scales for the temporal variability in the alongshore and offshore velocities are 10.2 and 5.4 days, respectively. Good vertical correlation exists between the alongshore or onshore velocity fluctuations, excluding the Agulhas Undercurrent. The lateral scale for the thermocline Agulhas current is about 60 km and the onshore velocity correlations are positive throughout the Agulhas Current system. Mean velocities from the array determine that the offshore edge of the Agulhas Current lies at 203 km and the penetration depth is 2200 m offshore of the Undercurrent. Hence, daily averaged velocity sections, determined by interpolation and extrapolation of current meter locations, for a 267-day period, from the surface to 2400 m depth and from the coast out to 203 km offshore encompass the main features of the Agulhas Current system. The Agulhas current is generally found close to the continental slope, within 31 km of the coast for 211 of 267 days. There are only five days when the core of the current is found offshore at 150 km. Total transport is always poleward, varying from −121 to −9 Sv, with maximum transport occurring when the core is 62 km from the coast. Average total transport for the 267 day period is −69.7 Sv; the standard deviation in daily transport values is 21.5 Sv; and the mean transport has an estimated standard error of 4.3 Sv. The Agulhas Undercurrent, which hugs the continental slope below the zero velocity isotach, has an average equatorward transport of 4.2 Sv, standard deviation of 2.9 Sv and an estimated standard error of 0.4 Sv. Transports from the moored array are in reasonable agreement with transport results from synoptic sections. Based on time series measurements at about 30° latitude in each ocean basin, the Agulhas Current is the largest western boundary current in the world ocean. 相似文献