495 research outputs found
Does persistent snowpack inhibit degradation of fecal stress indicators?
Physiological stress in wildlife can be a useful indicator of a population’s response to environmental factors. By using non-invasive endocrinological techniques, such as fecal sampling, potential confounding factors associated with the stress of capture can be avoided. A potential drawback of fecal sampling, however, is degradation of samples which may produce aberrant measurements of fecal glucocorticoid metabolites. In vertebrates, glucocorticoids, such as corticosterone, become elevated in response to stress. We sought to gauge the reliability of measurement of fecal glucocorticoid metabolites from white-tailed deer (Odocoileus virginianus) fecal samples exposed to a temperate winter with substantial snow cover and cold temperatures for up to 90 days, by repeatedly subsampling fecal samples every 10 days and performing a corticosterone enzyme-linked immunosorbent assay (ELISA). Measurements of fecal glucocorticoid metabolites at 10 days were consistent with initial measurements, after which (20 days) they became aberrant following a period of thawing. Consequently, glucocorticoid metabolite levels in feces appear to remain stable under ambient conditions if temperatures remain below freezing at least for 10 days. While it’s possible that samples may remain useful beyond this time frame based on previous laboratory studies of samples stored in a freezer, further work is needed to determine how samples weather in situ under extreme cold (e.g. Arctic) or periods of partial thawing
Urban built environment configuration and psychological distress in older men: Results from the Caerphilly study
Background
Few studies have examined the impact of the built environment configuration upon mental health. The study examines the impact of objectively assessed land use and street network configuration upon psychological distress and whether this association is moderated by the natural environment and area-level deprivation.
Methods
In a community sample of 687 older men from the Caerphilly Prospective Study, built environment morphological metrics (morphometrics) were related to differences in psychological distress as measured by the General Health Questionnaire. Cross-sectional data were taken from the most recent (5th) phase. A multi-level analysis with individuals nested within census-defined neighbourhoods was conducted. Environmental measures comprised GIS-constructed land use and street network metrics, slope variability and a satellite derived measure of greenness.
Results
Reduced psychological distress was associated with residing in a terraced dwelling (OR = 0.48, p = 0.03), higher degrees of land-use mix (OR = 0.42, p = 0.03 for the high tertile) and having higher local-level street-network accessibility (‘movement potential’) (OR = 0.54, p = 0.03). Hillier topography with higher slope variability was associated with increased risks of psychological distress (OR = 1.38, p = 0.05).
Conclusions
The findings support our hypothesis that built environment configuration is independently associated with psychological distress. The study underscores the need for effective intervention in the planning and design of residential built environment to achieve the goal of health-sustaining communities
Power in the Land
In 1542 William Ramsden bought his wife’s family home at Longley and so began a long association between the Ramsdens and Huddersfield which lasted until Sir John Frecheville Ramsden sold his greatly increased Huddersfield estate to the Corporation in 1920. This collection of essays is published to commemorate the centenary of that event. Seven local historians examine different aspects of the Ramsden family’s relationship with the town and its inhabitants, especially in the nineteenth century. The book incorporates new research and gives fresh insights into the events which led to Huddersfield becoming ‘the town that bought itself’ a century ago
Analysis of DGGE profiles to explore the relationship between prokaryotic community composition and biogeochemical processes in deep subseafloor sediments from the Peru Margin
The aim of this work was to relate depth profiles of prokaryotic community composition with geochemical processes in the deep subseafloor biosphere at two shallow-water sites on the Peru Margin in the Pacific Ocean (ODP Leg 201, sites 1228 and 1229). Principal component analysis of denaturing gradient gel electrophoresis banding patterns of deep-sediment Bacteria, Archaea, Euryarchaeota and the novel candidate division JS1, followed by multiple regression, showed strong relationships with prokaryotic activity and geochemistry (R2=55–100%). Further correlation analysis, at one site, between the principal components from the community composition profiles for Bacteria and 12 other variables quantitatively confirmed their relationship with activity and geochemistry, which had previously only been implied. Comparison with previously published cell counts enumerated by fluorescent in situ hybridization with rRNA-targeted probes confirmed that these denaturing gradient gel electrophoresis profiles described an active prokaryotic communit
Diversity of prokaryotes and methanogenesis in deep subsurface sediments from the Nankai Trough, Ocean Drilling Program Leg 190
Diversity of Bacteria and Archaea was studied in deep marine sediments by PCR amplification and sequence analysis of 16S rRNA and methyl co-enzyme M reductase (mcrA) genes. Samples analysed were from Ocean Drilling Program (ODP) Leg 190 deep subsurface sediments at three sites spanning the Nankai Trough in the Pacific Ocean off Shikoku Island, Japan. DNA was amplified, from three depths at site 1173 (4.15, 98.29 and 193.29 mbsf; metres below the sea floor), and phylogenetic analysis of clone libraries showed a wide variety of uncultured Bacteria and Archaea. Sequences of Bacteria were dominated by an uncultured and deeply branching ‘deep sediment group’ (53% of sequences). Archaeal 16S rRNA gene sequences were mainly within the uncultured clades of the Crenarchaeota. There was good agreement between sequences obtained independently by cloning and by denaturing gradient gel electrophoresis. These sequences were similar to others retrieved from marine sediment and other anoxic habitats, and so probably represent important indigenous bacteria. The mcrA gene analysis suggested limited methanogen diversity with only three gene clusters identified within the Methanosarcinales and Methanobacteriales. The cultivated members of the Methanobacteriales and some of the Methanosarcinales can use CO2 and H2 for methanogenesis. These substrates also gave the highest rates in 14C-radiotracer estimates of methanogenic activity, with rates comparable to those from other deep marine sediments. Thus, this research demonstrates the importance of the ‘deep sediment group’ of uncultured Bacteria and links limited diversity of methanogens to the dominance of CO2/H2 based methanogenesis in deep sub-seafloor sediment
From Broken Windows to Perceived Routine Activities: Examining Impacts of Environmental Interventions on Perceived Safety of Urban Alleys
In high-density cities around the world, alleys are common but neglected spaces that are perceived as unsafe. While cities have invested resources in environmental interventions to improve safety in urban allies, it is not clear how these interventions impact perceived safety. We review two important criminology theories that discuss the environmental and social factors that lead to crime: the Broken Windows Theory and the Routine Activity Theory. We argue that these theories can also be used to explain safety perceptions of urban environments, and then develop urban alley interventions based on these theories. We test people's perceived safety of these interventions through a photograph survey. Results show that all interventions yielded higher perceived safety than existing alley scenes. Interventions based on the Broken Windows Theory (cleaning or vegetation interventions) yielded only modest improvements in perceived safety, while interventions based on the Routine Activity Theory (urban function interventions) yielded higher ratings. Our findings question the dominant use of the Broken Windows Theory in environmental interventions to promote perceived safety and argue for a more effective approach: urban function interventions inspired by the Routine Activity Theory
Challenges facing gap-based silviculture and possible solutions for mesic northern forests in North America
Gap-based silvicultural systems were developed under the assumption that richness, and diversity of tree species and other biota positively respond to variation in size of harvest-created canopy gaps. However, varying gap size alone often does not meet diversity objectives and broader goals to address contemporary forest conditions. Recent research highlights the need to consider site factors and history, natural disturbance models, within-gap structure and recruitment requirements in addition to light resources for desired tree diversity. This synthesis brings together silvicultural developments and ecological literature on gap-based management, highlighting interactions with other factors such as microsite conditions, non-tree vegetation and more. We pose a revised concept for managers and researchers to use in prescriptions and studies focused on integrated overstory and understory manipulations that increase structural complexity within and around canopy openings
Deep sub-seafloor prokaryotes stimulated at interfaces over geological time
The sub-seafloor biosphere is the largest prokaryotic habitat
on Earth1 but also a habitat with the lowest metabolic rates2.
Modelled activity rates are very low, indicating that most prokaryotes
may be inactive or have extraordinarily slow metabolism2.
Here we present results from two Pacific Ocean sites,
margin and open ocean, both of which have deep, subsurface
stimulation of prokaryotic processes associated with geochemical
and/or sedimentary interfaces. At 90m depth in the margin site,
stimulation was such that prokaryote numbers were higher (about
13-fold) and activity rates higher than or similar to near-surface
values. Analysis of high-molecular-mass DNA confirmed the
presence of viable prokaryotes and showed changes in biodiversity
with depth that were coupled to geochemistry, including a marked
community change at the 90-m interface. At the open ocean
site, increases in numbers of prokaryotes at depth were more
restricted but also corresponded to increased activity; however, this
time they were associated with repeating layers of diatomrich
sediments (about 9Myr old). These results show that deep
sedimentary prokaryotes can have high activity, have changing
diversity associated with interfaces and are active over geological
timescales
The Methane Diurnal Variation and Microseepage Flux at Gale Crater, Mars as Constrained by the ExoMars Trace Gas Orbiter and Curiosity Observations
The upper bound of 50 parts per trillion by volume for Mars methane above 5 km established by the ExoMars Trace Gas Orbiter, substantially lower than the 410 parts per trillion by volume average measured overnight by the Curiosity Rover, places a strong constraint on the daytime methane flux at the Gale crater. We propose that these measurements may be largely reconciled by the inhibition of mixing near the surface overnight, whereby methane emitted from the subsurface accumulates within meters of the surface before being mixed below detection limits at dawn. A model of this scenario allows the first precise calculation of microseepage fluxes at Gale to be derived, consistent with a constant 1.5 à 10â 10 kg·mâ 2·solâ 1 (5.4 à 10â 5 tonnes·kmâ 2·yearâ 1) source at depth. Under this scenario, only 2.7 à 104 km2 of Mars’s surface may be emitting methane, unless a fast destruction mechanism exists.Plain Language SummaryThe ExoMars Trace Gas Orbiter and the Curiosity Rover have recorded different amounts of methane in the atmosphere on Mars. The Trace Gas Orbiter measured very little methane (<50 parts per trillion by volume) above 5 km in the sunlit atmosphere, while Curiosity measured substantially more (410 parts per trillion by volume) near the surface at night. In this paper we describe a framework which explains both measurements by suggesting that a small amount of methane seeps out of the ground constantly. During the day, this small amount of methane is rapidly mixed and diluted by vigorous convection, leading to low overall levels within the atmosphere. During the night, convection lessens, allowing methane to build up near the surface. At dawn, convection intensifies and the nearâ surface methane is mixed and diluted with much more atmosphere. Using this model and methane concentrations from both approaches, we are ableâ for the first timeâ to place a single number on the rate of seepage of methane at Gale crater which we find equivalent to 2.8 kg per Martian day. Future spacecraft measuring methane near the surface of Mars could determine how much methane seeps out of the ground in different locations, providing insight into what processes create that methane in the subsurface.Key PointsNighttime SAMâ TLS seasonal cycle enrichment measurements and TGO sunset/sunrise measurements are not in oppositionMicroseepage fluxes must be local to Gale, range from 0.82 to 4.6 kg/sol, and are consistent with a constant source at depthLittle of Mars experiences microseepage unless a fast destruction mechanism exists or Gale is very unusualPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151840/1/grl59471-sup-0001-2019GL083800-SI.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151840/2/grl59471_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151840/3/grl59471.pd
Subsurface microbiology and biogeochemistry of a deep, cold-water carbonate mound from the Porcupine Seabight (IODP Expedition 307)
The Porcupine Seabight Challenger Mound is the first carbonate mound to be drilled (∼270 m) and analyzed in detail microbiologically and biogeochemically. Two mound sites and a non-mound Reference site were analyzed with a range of molecular techniques [catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH), quantitative PCR (16S rRNA and functional genes, dsrA and mcrA), and 16S rRNA gene PCR-DGGE] to assess prokaryotic diversity, and this was compared with the distribution of total and culturable cell counts, radiotracer activity measurements and geochemistry. There was a significant and active prokaryotic community both within and beneath the carbonate mound. Although total cell numbers at certain depths were lower than the global average for other subseafloor sediments and prokaryotic activities were relatively low (iron and sulfate reduction, acetate oxidation, methanogenesis) they were significantly enhanced compared with the Reference site. In addition, there was some stimulation of prokaryotic activity in the deepest sediments (Miocene, > 10 Ma) including potential for anaerobic oxidation of methane activity below the mound base. Both Bacteria and Archaea were present, with neither dominant, and these were related to sequences commonly found in other subseafloor sediments. With an estimate of some 1600 mounds in the Porcupine Basin alone, carbonate mounds may represent a significant prokaryotic subseafloor habitat
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