982 research outputs found
Pygomelia or supernumerary limbs in a crossbred calf
A crossbred (Sindhi Ă— local indigenous) calf that was 12 days old was admitted to the Teaching Veterinary Hospital, Chittagong Government Veterinary College, Bangladesh, with two accessory hind limbs attached to the pelvic region in between the hind legs. This was clinically identified as a congenital anomaly popularly called pygomelia. The pygomelia was successfully corrected by surgical excisions
A novel interplanetary communications relay
A case study of a potential Earth-Mars interplanetary communications relay, designed to ensure continuous communications, is detailed. The relay makes use of orbits based on artificial equilibrium points via the application of continuous low thrust, which allows a spacecraft to hover above the orbital plane of Mars and thus ensure communications when the planet is occulted with respect to the Earth. The artificial equilibria of two different low-thrust propulsion technologies are considered: solar electric propulsion, and a solar sail/solar electric propulsion hybrid. In the latter case it is shown that the combination of sail and solar electric propulsion may prove advantageous, but only under specific circumstances of the relay architecture suggested. The study takes into account factors such as the spacecraft's power requirements and communications band utilized to determine the mission and system architecture. A detailed contingency analysis is considered for recovering the relay after increasing periods of spacecraft motor failure, and combined with a consideration for how best to deploy the relay spacecraft to maximise propellant reserves and mission duration
Improved Collective Thomson Scattering measurements of fast ions at ASDEX Upgrade
Understanding the behaviour of the confined fast ions is important in both
current and future fusion experiments. These ions play a key role in heating
the plasma and will be crucial for achieving conditions for burning plasma in
next-step fusion devices. Microwave-based Collective Thomson Scattering (CTS)
is well suited for reactor conditions and offers such an opportunity by
providing measurements of the confined fast-ion distribution function resolved
in space, time and 1D velocity space. We currently operate a CTS system at
ASDEX Upgrade using a gyrotron which generates probing radiation at 105 GHz. A
new setup using two independent receiver systems has enabled improved
subtraction of the background signal, and hence the first accurate
characterization of fast-ion properties. Here we review this new dual-receiver
CTS setup and present results on fast-ion measurements based on the improved
background characterization. These results have been obtained both with and
without NBI heating, and with the measurement volume located close to the
centre of the plasma. The measurements agree quantitatively with predictions of
numerical simulations. Hence, CTS studies of fast-ion dynamics at ASDEX Upgrade
are now feasible. The new background subtraction technique could be important
for the design of CTS systems in other fusion experiments.Comment: 4 pages, 4 figures, to appear in Proc. of "Fusion Reactor
Diagnostics", eds. F. P. Orsitto et al., AIP Conf. Pro
Benchmark and combined velocity-space tomography of fast-ion D-alpha spectroscopy and collective Thomson scattering measurements
EFDA Task TW6-TPDS-DIADEV deliverable 2: ITER Fast Ion Collective Scattering Development of diagnostic components and techniques
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
Progress on the Fast Ion Millimetre Wave CTS Diagnostics on TEXTOR and ASDEX Upgrade and status of the CTS design for ITER
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