1,007 research outputs found
Pfizer Animal Health Gift
Wetlands perform certain functions, including water filtration and the provision of wildlife habitats, from which humans benefit in the form of drinkable water and biodiversity. Trees produce oxygen, capture air and water pollutants, and provide shade, which help humans breathe, manage storm waters, and find a comfortable place to relax on a hot day. These are services that are provided by functioning ecosystems and are measured through the ecological economics of ecosystem services. The study of ecosystem services has provided an important insight: for the most part, those very services are ignored or undervalued. Although humans derive enormous benefits from ecosystem services, these services are neither bought or sold in the marketplace, and, therefore, have no market value.
This Article applies the idea of ecosystem services to the management of watersheds and, in particular, the manner in which decisions in floodplains often undermine ecosystem functionality in floodplains. For instance, road and home construction along water courses and riverbed dredging can disrupt (or trade-off) the ecosystemâs ability to provide flood control and habitat services. The dangers in making such trade-off decisions are illustrated by the flood damage suffered during Tropical Storm Irene and contextualized within the framework of ecosystems services
The URBIS Partnership Proposal for Global Designation
The URBIS Partnership is proposing a designation process to recognize urban regionsâ efforts to engage in participatory, inclusive, and comprehensive approaches in urban planning for sustainability. Through this process, sustainable management practices would be developed and then cataloged for sharing and dissemination as part of a site-based global knowledge network. The URBIS Partnership is inviting expertise in fields including urban ecology, environmental education, policy, and urban planning to develop this process. Currently, urban regions involved include Stockholm, Montreal, Shanghai, Cape Town, Chicago, Istanbul, New Orleans, and New York. This effort will culminate in the establishment of the URBIS Partnership with the CBD Global Partnership of Cities and Biodiversity and other collaborators at the City Biodiversity Summit at Nagoya, Japan, the 10th Conference of the Parties to the Convention on Biological Diversity
Receptor mechanisms in olfaction
This thesis is a study of receptor-mediated events occurring in olfaction. Potential enzymes involved in olfactory transduction were investigated using standard biochemical techniques, and an investigation of the fatty acid receptor/s was attempted using psychophysical methods.
1. Other investigators in olfaction have recently demonstrated an odorant modulated adenylate cyclase in the frog. We have shown that tissue preparations from the rat have high levels of the enzyme adenylate cyclase. This activity was stimulated in the presence of odorants by up to two times the basal value. The concentrations of odorants used were in the range expected to be physiologically relevant. Both basal and stimulated adenylate cyclase were inhibited by ÎŒM calcium ion. Tissue preparations from brain showed no odorant activation. Guanylate cyclase was present at a tenth the concentration of adenylate cyclase and showed no odorant simulation.
2. There are no studies in the literature characterising the cyclic nucleotide phosphodiesterases in olfactory tissue. The Sutherland criteria require the presence of a cyclic nucleotide phosphodiesterase (PDE) in olfactory tissue, if cyclic AMP is to be a second messenger in olfaction. It is possible that olfactory PDE is directly regulated by a receptor, as is found in vision. It is important, therefore, that the PDEâs in olfactory tissue are characterised.
Tissue preparations of the rat and sheep were shown to have high levels of cyclic nucleotide phosphodiesterase. The activities were not stimulated in the presence of physiologically relevant concentrations of odorants; inhibition of these activities by odorants was not significantly different from that of brain homogenates. Characterisation of the phosphodiesterase isoenzymes separated by DEAE chromatography established that they resembled the isoenzymes characterised from other tissues. The evidence presented indicates that olfactory tissue does not resemble visual tissue, which has a receptor-linked phosphodiesterase. All evidence suggests that PDEâs in olfactory tissue serve to return cyclic nucleotide concentrations to resting levels after stimulation. The observation that the Type 1 (calcium/calmodulin stimulated) phosphodiesterase is present in high concentrations in olfactory tissue suggests that calcium ion concentration in vivo may be an important regulator of phosphodiesterase activity.
3. The threshold values of various short chain fatty acids, of high purity, were determined using human subjects. The results were one order of magnitude greater than found by Amoore (1970) but showed a similar group trend. Descriptive analysis was also performed on these acids by generating a series of descriptors sufficient to discriminate between the acids. Analysis of the results by principal component analysis yielded a three dimensional map that showed the acids clustering into four groups. These four groups could indicate the presence of four receptors. Attempts to demonstrate structure-activity relationships between the thresholds, and descriptive analysis results with various physical and chemical parameters, failed. This was probably due to the interaction of the acids with more than one receptor.
So far, the lack of success in identifying olfactory receptors by researchers has meant that investigations of olfactory receptors have had to be done using psychophysical techniques such as those used in this report. It will probably not be known if these methods are useful for identifying receptors, until the receptors can be purified and characterised biochemically
Endothelial cell vasodilator dysfunction mediates progressive pregnancy-induced hypertension in endothelial cell tetrahydrobiopterin deficient mice.
Background and purpose: Pregnancy-associated vascular remodelling is essential for both maternal and fetal health. We have previously shown that maternal endothelial cell tetrahydrobiopterin (BH4) deficiency causes poor pregnancy outcomes. Here, we investigated the role and mechanisms of endothelial cell-mediated vasorelaxation function in these outcomes.
Experimental approach: The vascular reactivity of mouse aortas and uterine arteries from non-pregnant and pregnant endothelial cell-specific BH4 deficient mice (Gch1fl/flTie2cre mice) was assessed by wire myography. Systolic blood pressure was assessed by tail cuff plethysmography.
Key results: In late pregnancy, systolic blood pressure was significantly higher (âŒ24 mmHg) in Gch1fl/flTie2cre mice compared with wild-type littermates. This was accompanied by enhanced vasoconstriction and reduced endothelial-dependent vasodilation in both aorta and uterine arteries from pregnant Gch1fl/flTie2cre mice. In uterine arteries loss of eNOS-derived vasodilators was partially compensated by upregulation of intermediate and large-conductance Ca2+-activated K+ channels. In rescue experiments, oral BH4 supplementation alone did not rescue vascular dysfunction and pregnancy-induced hypertension in Gch1fl/flTie2cre mice. However, combination with the fully reduced folate, 5-methyltetrahydrofolate (5-MTHF), restored endothelial cell vasodilator function and blood pressure.
Conclusions and implications: We identify a critical requirement for maternal endothelial cell Gch1/BH4 biosynthesis in endothelial cell vasodilator function in pregnancy. Targeting vascular Gch1 and BH4 biosynthesis with reduced folates may provide a novel therapeutic target for the prevention and treatment of pregnancy-related hypertension
Radio source calibration for the VSA and other CMB instruments at around 30 GHz
Accurate calibration of data is essential for the current generation of CMB
experiments. Using data from the Very Small Array (VSA), we describe procedures
which will lead to an accuracy of 1 percent or better for experiments such as
the VSA and CBI. Particular attention is paid to the stability of the receiver
systems, the quality of the site and frequent observations of reference
sources. At 30 GHz the careful correction for atmospheric emission and
absorption is shown to be essential for achieving 1 percent precision. The
sources for which a 1 percent relative flux density calibration was achieved
included Cas A, Cyg A, Tau A and NGC7027 and the planets Venus, Jupiter and
Saturn. A flux density, or brightness temperature in the case of the planets,
was derived at 33 GHz relative to Jupiter which was adopted as the fundamental
calibrator. A spectral index at ~30 GHz is given for each. Cas A,Tau A, NGC7027
and Venus were examined for variability. Cas A was found to be decreasing at
percent per year over the period March 2001 to August 2004.
In the same period Tau A was decreasing at percent per year. A
survey of the published data showed that the planetary nebula NGC7027 decreased
at percent per year over the period 1967 to 2003. Venus showed
an insignificant ( percent) variation with Venusian illumination.
The integrated polarization of Tau A at 33 GHz was found to be
percent at pa .}Comment: 13 pages, 15 figures, submitted to MNRA
Use of ubiquitous real-time bus passenger information
Ubiquitous real-time passenger information (URTPI) enhances the perceived quality of service of public transport and enables travellers to make better pre-trip and en-route travel choices. The paper presents an exploratory study of the use of URTPI. We analyse the popularity of this kind of information, of the sources through which it is disseminated, and of the contents that it conveys. In particular, we are interested in the effects of trip characteristics and socio-demographic features of passengers. Our findings are based on 1645 responses collected through a bus passenger survey in the city of Edinburgh, UK. We find that access to URTPI is particularly related to the perceived length of the trips and age of the traveller. The most popular source of URTPI is bespoke apps providing information on bus arrival times, although non-residents require more detailed information. The study paves the way for further investigations into the impact of information on passengers' choices
Meeting the ISTE Challenge in the Field: An Overview of the First Six Distinguished Achievement Award Winning Programs
The 2002 National Educational Technology Standards (NETS) Distinguished Achievement Awards, sponsored by the International Society for Technology in Education (ISTE), were awarded to six teacher education programs across the United States. The awards recognize institutions that exemplify successful integration of the National Educational Technology Standards for Teachers (NETS[solid dot]T) into teacher education programs. Institutions across the country completed an extensive application process to be selected one of the first six recipients of the ISTE Distinguished Achievement award. This process included online documentation that demonstrated the program\u27s implementation of the NETS[solid dot]T models and practices. This article provides a means of uniting various programs and program developers (teacher educators and instructional technologists) by looking at the most common obstacles they face in the pursuit of appropriate infusion of technology into teacher education programs and workable solutions for overcoming those obstacles
A VSA search for the extended Sunyaev-Zel'dovich Effect in the Corona Borealis Supercluster
We present interferometric imaging at 33 GHz of the Corona Borealis
supercluster, using the extended configuration of the Very Small Array. A total
area of 24 deg^2 has been imaged, with an angular resolution of 11 arcmin and a
sensitivity of 12 mJy/beam. The aim of these observations is to search for
Sunyaev-Zel'dovich (SZ) detections from known clusters of galaxies in this
supercluster and for a possible extended SZ decrement due to diffuse warm/hot
gas in the intercluster medium. We measure negative flux values in the
positions of the ten richest clusters in the region. Collectively, this implies
a 3.0-sigma detection of the SZ effect. In the clusters A2061 and A2065 we find
decrements of approximately 2-sigma. Our main result is the detection of two
strong and resolved negative features at -70+-12 mJy/beam (-157+-27 microK) and
-103+-10 mJy/beam (-230+-23 microK), respectively, located in a region with no
known clusters, near the centre of the supercluster. We discuss their possible
origins in terms of primordial CMB anisotropies and/or SZ signals related to
either unknown clusters or to a diffuse extended warm/hot gas distribution. Our
analyses have revealed that a primordial CMB fluctuation is a plausible
explanation for the weaker feature (probability of 37.82%). For the stronger
one, neither primordial CMB (probability of 0.33%) nor SZ can account alone for
its size and total intensity. The most reasonable explanation, then, is a
combination of both primordial CMB and SZ signal. Finally, we explore what
characteristics would be required for a filamentary structure consisting of
warm/hot diffuse gas in order to produce a significant contribution to such a
spot taking into account the constraints set by X-ray data.Comment: 16 pages, 10 figures. Accepted in MNRA
Analytical approaches for transplant research
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73605/1/j.1600-6135.2004.00402.x.pd
Three-dimensional microCT imaging of mouse development from early post-implantation to early postnatal stages
AbstractIn this work, we report the use of iodine-contrast microCT to perform high-throughput 3D morphological analysis of mouse embryos and neonates between embryonic day 8.5 to postnatal day 3, with high spatial resolution up to 3”m/voxel. We show that mouse embryos at early stages can be imaged either within extra embryonic tissues such as the yolk sac or the decidua without physically disturbing the embryos. This method enables a full, undisturbed analysis of embryo turning, allantois development, vitelline vessels remodeling, yolk sac and early placenta development, which provides increased insights into early embryonic lethality in mutant lines. Moreover, these methods are inexpensive, simple to learn and do not require substantial processing time, making them ideal for high throughput analysis of mouse mutants with embryonic and early postnatal lethality
- âŠ