7,400 research outputs found
Synthesis of 1 alpha,25-Dihydroxyvitamin D Analogues Featuring a S-2-symmetric CD-ring Core
Three analogues of 1 alpha,25-dihydroxyvitamin D-3 (calcitriol), featuring a transfused decalin C, D-core with local S-2-symmetry, and possessing identical side-chain and seco-B,A-ring structures, have been synthesized starting from readily available (4aR, 8aS)octahydronaphthalene-1,5-dione(7). The very short sequences involve the simultaneous introduction of the side-chain and seco-B, A-ring fragments via Suzuki and Sonogashira coupling reactions. The analogues are devoid of relevant biological activity
Nutrition-sensitive value chains from a smallholder perspective: A framework for project design
"The Alliance of Bioversity International and the International Center for Tropical Agriculture (CIAT) gratefully acknowledges permission from IFAD to re-publish that work as an Alliance Working Paper, with updated acknowledgements, author information and information on additional resources.
A Deep WSRT 1.4 GHz Radio Survey of the Spitzer Space Telescope FLSv Region
The First Look Survey (FLS) is the first scientific product to emerge from
the Spitzer Space Telescope. A small region of this field (the verification
strip) has been imaged very deeply, permitting the detection of cosmologically
distant sources. We present Westerbork Synthesis Radio Telescope (WSRT)
observations of this region, encompassing a ~1 sq. deg field, centred on the
verification strip (J2000 RA=17:17:00.00, DEC=59:45:00.000). The radio images
reach a noise level of ~ 8.5 microJy/beam - the deepest WSRT image made to
date. We summarise here the first results from the project, and present the
final mosaic image, together with a list of detected sources. The effect of
source confusion on the position, size and flux density of the faintest sources
in the source catalogue are also addressed. The results of a serendipitous
search for HI emission in the field are also presented. Using a subset of the
data, we clearly detect HI emission associated with four galaxies in the
central region of the FLSv. These are identified with nearby, massive galaxies.Comment: 9 pages, 6 figures (fig.3 in a separate gif file). Accepted for
publication in A&A. The full paper and the related material can be downloaded
from http://www.astron.nl/wsrt/WSRTsurveys/WFLS
WSRT 1.4 GHz Observations of the Hubble Deep Field
We present WSRT 1.38 GHz observations of the Hubble Deep Field (and flanking
fields). 72 hours of data were combined to produce the WSRT's deepest image
yet, achieving an r.m.s. noise level of 8 microJy per beam. We detect radio
emission from galaxies both in the HDF and HFF which have not been previously
detected by recent MERLIN or VLA studies of the field.Comment: 2 pages, 1 figure, to appear in "The Universe at Low Radio
Frequencies", IAU Symposium 199. For colour figures, see
http://www.nfra.nl/~mag/hdf_wsrt.htm
Fatigue behaviour of metallic components obtained by topology optimization for additive manufacturing
Gay community periodic survey: Melbourne 2015
This study finds that HIV testing by gay and bisexual men in Melbourne continues to increase.
Executive summary
The Melbourne Gay Community Periodic Survey is a cross-sectional survey of gay and homosexually active men recruited at a range of gay community sites in Melbourne. The major aim of the survey is to provide data on sexual, drug use, and testing practices related to the transmission of HIV and other sexually transmissible infections (STIs) among gay men. The most recent survey, the seventeenth in Melbourne, recruited a total of 3,006 men in January 2015. The majority of these men (n=2,429, 81%) were recruited using face-to-face recruitment by trained staff at gay social venues (e.g. bars and community organisations), sex-on-premises venues, sexual health clinics, and the Midsumma Carnival. The remaining 577 men (19%) participated through an online version of the survey.
Online recruitment was conducted for the first time in 2015 through the social networking site Facebook. Men were directed to a website with an online version of the GCPS questionnaire (http://gcpsonline.net). The advertisements were targeted to all men aged 16 and above who were located in Victoria and indicated in their Facebook profile that they were ‘interested’ in men.
From its start in 1998, the project has been funded by the Victorian Department of Health and supported by the Victorian AIDS Council and Living Positive Victoria. The Centre for Social Research in Health coordinates the survey, with support from the Kirby Institute.
The overall response rate for the 2015 survey was 77%. The data presented in this report are from the period 2011 to 2015.
Since 2011, there have been significant decreases in the proportions of men recruited at sexual health clinics, social venues, and the Midsumma Carnival. The proportion of men recruited from sex-on-premises venues has remained stable over time.
The online sample was analysed before we incorporated it into the survey database. There were a number of differences between men recruited online and men recruited through venues and events. Men in the online sample were younger and were more likely to be born in Australia. Men in the online sample were also less likely to report testing for HIV in the 12 months prior to the survey and were more likely to report that they were HIV-negative. Compared to men recruited through physical venues, men recruited through online survey were more likely to be in a monogamous relationship and have condomless anal intercourse with their regular partner. They were also more likely to report condomless anal intercourse with casual partners and were less likely to know that PEP was available. The online and offline samples reported similar rates of STI testing and drug use.
However, despite these differences, when we merged the online and offline samples, the majority of key indicators did not appear to be affected by the change in sampling methods. We have therefore incorporated the online sample into the combined database and the reporting of trends. We will, however, continue to monitor the impact of online recruitment on the sample over time
Frontal plane stabilization and hopping with a 2DOF tail
The Jerboa, a tailed bipedal robot with two hip-actuated, passive-compliant legs and a doubly actuated tail, has been shown both formally and empirically to exhibit a variety of stable hopping and running gaits in the sagittal plane. In this paper we take the first steps toward operating Jerboa as a fully spatial machine by addressing the predominant mode of destabilization away from the sagittal plane: body roll. We develop a provably stable controller for underactuated aerial stabilization of the coupled body roll and tail angles, that uses just the tail torques. We show that this controller is successful at reliably reorienting the Jerboa body in roughly 150 ms of freefall from a large set of initial conditions. This controller also enables (and appears intuitively to be crucial for) sustained empirically stable hopping in the frontal plane by virtue of its substantial robustness against destabilizing perturbations and calibration errors. The controller as well as the analysis methods developed here are applicable to any robotic platform with a similar doubly-actuated spherical tail joint
Assessment of climate change statistical downscaling methods: Application and comparison of two statistical methods to a single site in Lisbon
Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Engenharia do AmbienteClimate change impacts are very dependent on regional geographical features, local climate
variability, and socio-economic conditions. Impact assessment studies on climate change
should therefore be performed at the local or at most at the regional level for the evaluation of possible consequences. However, climate scenarios are produced by Global Circulation Models for the entire Globe with spatial resolutions of several hundred kilometres. For this reason, downscaling methods are needed to bridge the gap between the large scale climate
scenarios and the fine scale where local impacts happen.
An overview on downscaling techniques is presented, referring the main limitation and
advantages on dynamical, statistical and statistical-dynamic approaches. For teams with limited computing power and non-climate experts, statistical downscaling is currently the most feasible approach at obtaining climate data for future impact studies.
To assess the capability of statistical downscaling methods to represent local climate variability it is shown an inter-comparison and uncertainties analysis study between a stochastic weather generator, using LARS-WG tool, and a hybrid of stochastic weather generator and transfer function methods, using the SDSM tool. Models errors and uncertainties were estimated using non-parametric statistical methods at the 95% confidence interval for precipitation, maximum temperature and minimum temperature for the mean and variance for a single site in Lisbon.
The comparison between the observed dataset and the simulations showed that both
models performance are acceptable. However, the SDSM tool was able to better represent
the minimum and maximum temperature while LARS-WG simulations on precipitation are
better. The analysis of both models uncertainties for the mean are very close to the observed data in all months, but the uncertainties for the variances showed that the LARWG simulation performance is slightly better for precipitation and that both model
simulations for minimum and maximum temperature are very close from the observed.
It is also presented the simulations for the A2a SRES scenario for the 2041-2070 periods
showing that both methods can produce similar general tendencies, but an uncertainties analysis on the scenarios is also advised
Defining Your Double Bottom Line: Philanthropy and the Investment Landscape
Grantmaking traditionally has been at the heart of philanthropy, whereas impact was the exclusive expectation of any desired result. While there is still a place for this kind of pure push for change, many investors today expect more, leveraging the power of the markets to invest in a way that is both impactful and able to maximize their financial rewards. This is particularly true of foundations with an eye toward supporting the perpetuity of their missions and organizations.
This approach also offers a range of innovative mission-based benefits, including extending the utility of philanthropic capital and generating more capital to reinvest into impact initiatives, potentially in partnership or in tandem with grantmaking. However, the focus of impact has also shifted in radical new ways, especially over the last few years, in response to social developments and generational shifts in value. These shifts call for greater intentionality in defining the nuance and complexities involved in any use of the term “impact.”
This article argues the key importance of defining and crystalizing specific thresholds, metrics, and language around foundations’ missions to ensure demonstrable qualitative and quantitative measures of progress toward success (financially and impact-based); discusses how the long-term pursuit of values-based goals and financial performance are mutually inclusive and self-reinforcing, and can be combined to great effect with more traditional forms of philanthropy (i.e., grantmaking); and demonstrates how impact investing provides the opportunity for the engagement of additional stakeholders and members of the community.
This article also addresses several key questions: How has the use of philanthropic capital evolved from an investment perspective? What does an effective impact definition include? In which ways do impact and financial priorities buoy each other? How does one find credible sources of ESG/impact data and what determines high-quality data? And, finally, how can organizations best articulate their missions in their investment policy statements to better define their double bottom line
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