3,447 research outputs found
Quantifying the Extent of North American Mammal Extinction Relative to the Pre-Anthropogenic Baseline
Earth has experienced five major extinction events in the past 450 million years. Many scientists suggest we are now witnessing a sixth, driven by human impacts. However, it has been difficult to quantify the real extent of the current extinction episode, either for a given taxonomic group at the continental scale or for the worldwide biota, largely because comparisons of pre-anthropogenic and anthropogenic biodiversity baselines have been unavailable. Here, we compute those baselines for mammals of temperate North America, using a sampling-standardized rich fossil record to reconstruct species-area relationships for a series of time slices ranging from 30 million to 500 years ago. We show that shortly after humans first arrived in North America, mammalian diversity dropped to become at least 15%–42% too low compared to the “normal” diversity baseline that had existed for millions of years. While the Holocene reduction in North American mammal diversity has long been recognized qualitatively, our results provide a quantitative measure that clarifies how significant the diversity reduction actually was. If mass extinctions are defined as loss of at least 75% of species on a global scale, our data suggest that North American mammals had already progressed one-fifth to more than halfway (depending on biogeographic province) towards that benchmark, even before industrialized society began to affect them. Data currently are not available to make similar quantitative estimates for other continents, but qualitative declines in Holocene mammal diversity are also widely recognized in South America, Eurasia, and Australia. Extending our methodology to mammals in these areas, as well as to other taxa where possible, would provide a reasonable way to assess the magnitude of global extinction, the biodiversity impact of extinctions of currently threatened species, and the efficacy of conservation efforts into the future
Exploring Communication Tendencies of Program Facilitators
Audience analysis is a critical skill to forge relationships and develop effective communications. Programs provided by the Cooperative Extension Service must be aware of external and internal audiences to provide relevant information and evoke impacts. Berlo’s (1960) Source-Message-Channel-Receiver Model of Communications guided this formative evaluation of Extension staff, and horse 4-H club volunteer leaders (program facilitators) to expose internal communication tendencies in Arkansas. Findings identified that program facilitators seek horse-related information from a variety of sources, most frequently relying on personal connections and least frequently seeking Extension sources. Program facilitators share a variety of messages and most frequently relay information about deadlines to club members. Messages about recruitment and fundraising were shared least often. Program facilitators described utilizing a variety of personal and electronic channels to share messages with the greatest frequency for in-person communications. Incoming channels were less diverse than outgoing channels and primarily featured email, which program facilitators preferred. Program facilitators are primarily female, aged in their thirties, described lifetime involvement with 4-H and the horse industry, and most frequently reported having less than five years’ experience in their current position. The ground-level perspective of facilitators’ demographics and communication tendencies was evident in results of this study. In application, practitioners must continue to actively seek relationships with audiences, remain cognizant of communication factors, and provide accurate messaging through preferred channels
The serum proteome of Atlantic salmon, Salmo salar, during pancreas disease (PD) following infection with salmonid alphavirus subtype 3 (SAV3)
Salmonid alphavirus is the aetological agent of pancreas disease (PD) in marine Atlantic salmon, Salmo salar, and rainbow trout, Oncorhynchus mykiss, with most outbreaks in Norway caused by SAV subtype 3 (SAV3). This atypical alphavirus is transmitted horizontally causing a significant economic impact on the aquaculture industry. This histopathological and proteomic study, using an established cohabitational experimental model, investigated the correlation between tissue damage during PD and a number of serum proteins associated with these pathologies in Atlantic salmon. The proteins were identified by two-dimensional electrophoresis, trypsin digest and peptide MS/MS fingerprinting. A number of humoral components of immunity which may act as biomarkers of the disease were also identified. For example, creatine kinase, enolase and malate dehydrogenase serum concentrations were shown to correlate with pathology during PD. In contrast, hemopexin, transferrin, and apolipoprotein, amongst others, altered during later stages of the disease and did not correlate with tissue pathologies. This approach has given new insight into not only PD but also fish disease as a whole, by characterisation of the protein response to infection, through pathological processes to tissue recovery.
Biological significance:
Salmonid alphavirus causes pancreas disease (PD) in Atlantic salmon, Salmo salar, and has a major economic impact on the aquaculture industry. A proteomic investigation of the change to the serum proteome during PD has been made with an established experimental model of the disease. Serum proteins were identified by two-dimensional electrophoresis, trypsin digest and peptide MS/MS fingerprinting with 72 protein spots being shown to alter significantly over the 12 week period of the infection. The concentrations of certain proteins in serum such as creatine kinase, enolase and malate dehydrogenase were shown to correlate with tissue pathology while other proteins such as hemopexin, transferrin, and apolipoprotein, altered in concentration during later stages of the disease and did not correlate with tissue pathologies. The protein response to infection may be used to monitor disease progression and enhance understanding of the pathology of PD
Development and evaluation of a new diffusive gradients in thin-films technique for measuring organotin compounds in coastal sediment pore water
Multimodal, Multidimensional Models of Mouse Brain
Naturally occurring mutants and genetically manipulated strains of mice are widely used to model a variety of human diseases. Atlases are an invaluable aid in understanding the impact of such manipulations by providing a standard for comparison and to facilitate the integration of anatomic, genetic, and physiologic observations from multiple subjects and experiments. We have developed digital atlases of the C57BL/6J mouse brain (adult and neonate) as comprehensive frameworks for storing and accessing the myriad types of information about the mouse brain. Along with raw and annotated images, these contain database management systems and a set of tools for comparing information from different techniques and different animals. Each atlas establishes a canonical representation of the mouse brain and provides the tools for the manipulation and analysis of new data. We describe both these atlases and discuss how they may be put to use in organizing and analyzing data from mouse models of epilepsy
Physical science research needed to evaluate the viability and risks of marine cloud brightening
Marine cloud brightening (MCB) is the deliberate injection of aerosol particles into shallow marine clouds to increase their reflection of solar radiation and reduce the amount of energy absorbed by the climate system. From the physical science perspective, the consensus of a broad international group of scientists is that the viability of MCB will ultimately depend on whether observations and models can robustly assess the scale-up of local-to-global brightening in today\u27s climate and identify strategies that will ensure an equitable geographical distribution of the benefits and risks associated with projected regional changes in temperature and precipitation. To address the physical science knowledge gaps required to assess the societal implications of MCB, we propose a substantial and targeted program of research-field and laboratory experiments, monitoring, and numerical modeling across a range of scales
Improvement in Chronic Hepatocerebral Degeneration Following Liver Transplantation
Chronic progressive hepatocerebral degeneration with spastic paraparesis, dementia, dysarthria, ataxia, tremor, and neuropsychiatric symptoms follows long-standing portal-systemic shunting, is associated with structural changes in the central nervous system, and does not respond to conventional therapy for hepatic encephalopathy. A case of advanced chronic liver disease with severe, progressive hepatocerebral degeneration after 23 yr of portal-systemic shunting is reported in whom there was significant objective improvement in intellectual function and in the chronic neurological signs 3 mo after orthotopic liver transplantation and further improvement 12 mo after transplantation
Heterologous Expression and Biochemical Characterisation of Fourteen Esterases from Helicoverpa armigera
Esterases have recurrently been implicated in insecticide resistance in Helicoverpa armigera but little is known about the underlying molecular mechanisms. We used a baculovirus system to express 14 of 30 full-length esterase genes so far identified from midgut cDNA libraries of this species. All 14 produced esterase isozymes after native PAGE and the isozymes for seven of them migrated to two regions of the gel previously associated with both organophosphate and pyrethroid resistance in various strains. Thirteen of the enzymes obtained in sufficient yield for further analysis all showed tight binding to organophosphates and low but measurable organophosphate hydrolase activity. However there was no clear difference in activity between the isozymes from regions associated with resistance and those from elsewhere in the zymogram, or between eight of the isozymes from a phylogenetic clade previously associated with resistance in proteomic and quantitative rtPCR experiments and five others not so associated. By contrast, the enzymes differed markedly in their activities against nine pyrethroid isomers and the enzymes with highest activity for the most insecticidal isomers were from regions of the gel and, in some cases, the phylogeny that had previously been associated with pyrethroid resistance. Phospholipase treatment confirmed predictions from sequence analysis that three of the isozymes were GPI anchored. This unusual feature among carboxylesterases has previously been suggested to underpin an association that some authors have noted between esterases and resistance to the Cry1Ac toxin from Bacillus thuringiensis. However these three isozymes did not migrate to the zymogram region previously associated with Cry1Ac resistance.This study was supported by an Australian Postgraduate Award and Top-up Scholarship from the Cotton Catchment Cummunities CRC to Claire
Farnsworth and the China Scholarship Council to Yongqiang Li. The funders had no role in study design, data collection and analysis, decision to publish, or
preparation of the manuscript
Consumption of a recommended serving of wheat bran cereals significantly increases human faecal butyrate levels in healthy volunteers and reduces markers of inflammation ex vivo.
Wheat bran cereals are an important source of dietary fibre. The aim of the study was to investigate if a high intake (120 g) of fibre rich breakfast cereal (which delivers the UK Government guidelines for fibre intake in one serving but is three-fold higher than the manufacturers recommended serving) has additional potential health benefits compared to the recommended serving (40 g, containing 11 g of dietary fibre). To assess this, the study determined the short chain fatty acid (SCFA) profiles in human faecal, urine and plasma samples after consumption of two different servings of fibre-rich cereal. Inhibition of prostanoid production was measured (ex vivo) in human colonic fibroblast cells after cytokine (IL-1β) inflammation stimulation. Eight healthy volunteers, 18-55 years old; BMI (18-30 kg/m2) consumed the wheat bran-rich "ready to eat cereal", at both the high (120 g) serving and recommended (40 g) serving. Faecal, urine and plasma samples were collected at baseline, throughout the five-hour intervention period and approximately 24 hours following consumption. Faecal butyrate showed the largest increase (p < 0.05) of more than a two-fold change following the consumption of the recommended serving of wheat bran cereal (from 13.95 ± 9.17 to 31.63 ± 20.53 mM) and no significant change following the higher serving (from 21.96 ± 11.03 to 22.9 ± 12.69 mM). ANOVA analysis also found a weak serving effect (p = 0.046) of the portion size (high vs. recommended) only for butyrate in urine 24 hours after consumption of the bran cereal. The physiological nutritionally relevant concentrations of faecal SCFAs, as determined in the volunteers' faecal samples showed significant anti-inflammatory activity or the individual faecal SCFAs; acetate (p < 0.001), propionate (p < 0.001) and butyrate (p < 0.01), as well as in combination. Plasma folate was also increased after consumption of both wheat bran servings and was significant (p = 0.037) at the three-hour time point following consumption of the high wheat bran serving. The consumption of the recommended serving (40 g) of wheat bran cereal increased the total microbial SCFAs levels (from 96.88 to 136.96 mM) compared to the higher serving (120 g) (from 110.5 to 117.64 mM) suggesting that the intake of the higher portion size is likely to promote a faecal bulking effect and thereby decrease colonic SCFA levels. These data indicate that consumption of the recommended serving of wheat bran cereal serving would therefore be sufficient to promote microbial butyrate formation, reduce colonic inflammation and increase plasma folate levels in humans
Advanced solid-state array spectroradiometer data collection during HAPEX-2 Sahel
Data collection using the Advanced Solid-state Array Spectroradiometer (ASAS) during the Hydrologic Atmospheric Pilot Experiment in the Sahel (HAPEX-II Sahel) field campaign in the Republic of Niger, West Central Africa from 22 Aug. to 19 Sep. 1992 is documented. Details on the ASAS system such as the hardware, data collection methods, information on system calibration, and data processing procedures are included. The ASAS configuration deployed for HAPEX-II Sahel contains several new components, including a new sensor array and pointing system. Because of this, new calibration procedures are being developed at the same time that the first ASAS images from HAPEX-II Sahel are being processed. These new calibration procedures will be documented in a future publication
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