488 research outputs found
Review of Orbiter Flight Boundary Layer Transition Data
In support of the Shuttle Return to Flight program, a tool was developed to predict when boundary layer transition would occur on the lower surface of the orbiter during reentry due to the presence of protuberances and cavities in the thermal protection system. This predictive tool was developed based on extensive wind tunnel tests conducted after the loss of the Space Shuttle Columbia. Recognizing that wind tunnels cannot simulate the exact conditions an orbiter encounters as it re-enters the atmosphere, a preliminary attempt was made to use the documented flight related damage and the orbiter transition times, as deduced from flight instrumentation, to calibrate the predictive tool. After flight STS-114, the Boundary Layer Transition Team decided that a more in-depth analysis of the historical flight data was needed to better determine the root causes of the occasional early transition times of some of the past shuttle flights. In this paper we discuss our methodology for the analysis, the various sources of shuttle damage information, the analysis of the flight thermocouple data, and how the results compare to the Boundary Layer Transition prediction tool designed for Return to Flight
Global governance approaches to addressing illegal logging: Uptake and lessons learned
One of the most challenging tasks facing development agencies, trade ministries, environmental groups, social activists and forest-focused business interests seeking to ameliorate illegal logging and related timber trade is to identify and nurture promising global governance interventions capable of helping improve compliance to governmental policies and laws at national, subnational and local levels. This question is especially acute for developing countries constrained by capacity challenges and “weak states” (Risse, 2011). This chapter seeks to shed light on this task by asking four related questions: How do we understand the emergence of illegal logging as a matter of global interest? What are the types of global interventions designed to improve domestic legal compliance? How have individual states responded to these global efforts? What are the prospects for future impacts and evolution?
We proceed in the following steps. Following this introduction, step two reviews how the problem of “illegal logging” emerged on the international agenda. Step three reviews leading policy interventions that resulted from this policy framing. Step four reviews developments in selected countries/regions around the world according to their place on the global forest products supply chain: consumers (United States, Europe and Australia); middle of supply chain manufacturers (China and South Korea) and producers (Russia; Indonesia; Brazil and Peru; Ghana, Cameroon and the Republic of Congo). We conclude by reflecting on key trends that emerge from this review relevant for understanding the conditions through which legality might make a difference in addressing critical challenges
Spatial Localization and Quantitation of Androgens in Mouse Testis by Mass Spectrometry Imaging
Androgens
are essential for male development and reproductive function.
They are transported to their site of action as blood-borne endocrine
hormones but can also be produced within tissues to act in intracrine
and paracrine fashions. Because of this, circulating concentrations
may not accurately reflect the androgenic influence within specific
tissue microenvironments. Mass spectrometry imaging permits regional
analysis of small molecular species directly from tissue surfaces.
However, due to poor ionization and localized ion suppression, steroid
hormones are difficult to detect. Here, derivatization with Girard
T reagent was used to charge-tag testosterone and 5α-dihydrotestosterone
allowing direct detection of these steroids in mouse testes, in both
basal and maximally stimulated states, and in rat prostate. Limits
of detection were ∼0.1 pg for testosterone. Exemplary detection
of endogenous steroids was achieved by matrix-assisted laser desorption
ionization and either Fourier transform ion cyclotron resonance detection
(at 150 μm spatial resolution) or quadrupole-time-of-flight
detection (at 50 μm spatial resolution). Structural confirmation
was achieved by collision induced fragmentation following liquid extraction
surface analysis and electrospray ionization. This application broadens
the scope for derivatization strategies on tissue surfaces to elucidate
local endocrine signaling in health and disease
BBC Audience Council Northern Ireland Advice to the BBC Trust Service Review of Nations’ Radio and News and Current Affairs
BBC Charter Review, BBC Audience Council Northern Ireland Submission to the BBC Trust, December 2015
BBC Trust Provisional Conclusions on BBC proposals for BBC Three, Audience Council Northern Ireland Advice to the Trust, September 2015
Ecological Interactions of the Sexually Deceptive Orchid Orchis Galilaea
Plant species dependent on highly specific interactions with pollinators are vulnerable to environmental change. Conservation strategies therefore require a detailed understanding of pollination ecology. This two-year study examined the interactions between the sexually deceptive
orchid, Orchis galilaea, and its pollinator Lasioglossum marginatum. Relationships were investigated across three different habitats known to support O. galilaea (garrigue, oak woodland, and mixed oak/pine woodland) in Lebanon. Visitation rates to flowers were extremely low and restricted to male bees. The reproductive success of O. galilaea under ambient conditions was 29.3% (±2.4), compared to 89.0% (±2.1) in plants receiving cross-pollination by hand. No difference in reproductive success was found between habitat types, but values of reproductive success were positively correlated to the abundance of male bees. Pollination limitation can have negative impacts on the population growth of orchids, and this study provides clear evidence for more holistic approaches to habitat conservation to support specific interactions
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