3,637 research outputs found
Random Matrix Models, Double-Time Painlev\'e Equations, and Wireless Relaying
This paper gives an in-depth study of a multiple-antenna wireless
communication scenario in which a weak signal received at an intermediate relay
station is amplified and then forwarded to the final destination. The key
quantity determining system performance is the statistical properties of the
signal-to-noise ratio (SNR) \gamma\ at the destination. Under certain
assumptions on the encoding structure, recent work has characterized the SNR
distribution through its moment generating function, in terms of a certain
Hankel determinant generated via a deformed Laguerre weight. Here, we employ
two different methods to describe the Hankel determinant. First, we make use of
ladder operators satisfied by orthogonal polynomials to give an exact
characterization in terms of a "double-time" Painlev\'e differential equation,
which reduces to Painlev\'e V under certain limits. Second, we employ Dyson's
Coulomb Fluid method to derive a closed form approximation for the Hankel
determinant. The two characterizations are used to derive closed-form
expressions for the cumulants of \gamma, and to compute performance quantities
of engineering interest.Comment: 72 pages, 6 figures; Minor typos corrected; Two additional lemmas
added in Appendix
CASPR: Judiciously Using the Cloud for Wide-Area Packet Recovery
We revisit a classic networking problem -- how to recover from lost packets
in the best-effort Internet. We propose CASPR, a system that judiciously
leverages the cloud to recover from lost or delayed packets. CASPR supplements
and protects best-effort connections by sending a small number of coded packets
along the highly reliable but expensive cloud paths. When receivers detect
packet loss, they recover packets with the help of the nearby data center, not
the sender, thus providing quick and reliable packet recovery for
latency-sensitive applications. Using a prototype implementation and its
deployment on the public cloud and the PlanetLab testbed, we quantify the
benefits of CASPR in providing fast, cost effective packet recovery. Using
controlled experiments, we also explore how these benefits translate into
improvements up and down the network stack
Crop diversification strategies for minor irrigation schemes: Proceedings of the workshop organized by the Irrigation Research Management Unit, Irrigation Department and the Sri Lanka National Program, International Irrigation Management Institute, held at the Irrigation Department, Colombo, Sri Lanka on 20 February 1996
Irrigation programs / Irrigation management / Small scale systems / Crops / Diversification / Rice / Cropping systems / Constraints / Social aspects / Economic aspects / Field crops / Crop production / Labor / Farmers' attitudes / Water management / Groundwater / Sri Lanka
Pioneering the human development revolution: Analysing the trajectory of Mahbub ul Haq
Mahbub ul Haq's work to coordinate, establish and propagate the human development approach offers an example of effective leadership in promoting more ethical socio-economic development. This article reviews Pioneering the Human Development Revolution-An Intellectual Biography of Mahbub ul Haq (edited by Haq and Ponzio), and extends themes from the United Nations Intellectual History Project to examine Haq's contributions in terms of four aspects of leadership: articulating and applying values that combine depth with broad appeal; providing a fruitful and vivid way of seeing, a 'vision', that reflects the values; embodying the values and vision in workable practical proposals; and supporting and communicating the previous aspects through wide and relevant networks. It suggests that the human development approach may need to update its values and vision, including through better integration of human security thinking, if it is to retain the leadership role it acquired thanks to Haq
Drug-induced stress granule formation protects sensory hair cells in mouse cochlear explants during ototoxicity
Stress granules regulate RNA translation during cellular stress, a mechanism that is generally presumed to be protective, since stress granule dysregulation caused by mutation or ageing is associated with neurodegenerative disease. Here, we investigate whether pharmacological manipulation of the stress granule pathway in the auditory organ, the cochlea, affects the survival of sensory hair cells during aminoglycoside ototoxicity, a common cause of acquired hearing loss. We show that hydroxamate (-)-9, a silvestrol analogue that inhibits eIF4A, induces stress granule formation in both an auditory cell line and ex-vivo cochlear cultures and that it prevents ototoxin-induced hair-cell death. In contrast, preventing stress granule formation using the small molecule inhibitor ISRIB increases hair-cell death. Furthermore, we provide the first evidence of stress granule formation in mammalian hair cells in-vivo triggered by aminoglycoside treatment. Our results demonstrate that pharmacological induction of stress granules enhances cell survival in native-tissue, in a clinically-relevant context. This establishes stress granules as a viable therapeutic target not only for hearing loss but also other neurodegenerative diseases.EI:595 - Action on Hearing Loss; 091092/Z/09/Z - Wellcome Trust (Wellcome); MR/N004329/1 - RCUK | Medical Research Council (MRC)Published versio
Heaviness, health and happiness: a cross-sectional study of 163 066 UK Biobank participants
<b>Background</b><p></p> Obesity is known to increase the risk of many diseases and reduce overall quality of life. This study examines the relationship with self-reported health (SRH) and happiness.<p></p>
<b>Methods</b> <p></p>We conducted a cross-sectional study of the 163 066 UK Biobank participants who completed the happiness rating. The association between adiposity and SRH and happiness was examined using logistic regression. SRH was defined as good (excellent, good), or poor (fair, poor). Self-reported happiness was defined as happy (extremely, very, moderately) or unhappy (moderately, very, extremely). <p></p>
<b>Results</b> <p></p>Poor health was reported by 44 457 (27.3%) participants. The adjusted ORs for poor health were 3.86, 2.92, 2.60 and 6.41 for the highest, compared with lowest, deciles of Body Mass Index, waist circumference, waist to hip ratio and body fat percent, respectively. The associations were stronger in men (p<0.001). Overall, 7511 (4.6%) participants felt unhappy, and only class III obese participants were more likely to feel unhappy (adjusted OR 1.33, 95% CI 1.15 to 1.53, p<0.001) but the associations differed by sex (p<0.001). Among women, there was a significant association between unhappiness and all levels of obesity. By contrast, only class III obese men had significantly increased risk and overweight and class I obese men were less likely to be unhappy. <p></p>
<b>Conclusions</b><p></p>Obesity impacts adversely on happiness as well as health, but the association with unhappiness disappeared after adjustment for self-reported health, indicating this may be mediated by health. Compared with obese men, obese women are less likely to report poor health, but more likely to feel unhappy. <p></p>
E-Commerce For Village Information System Using Agile Methodology
With the entry into the era of Industrial Revolution 4.0, the development of digitization of various aspects at the village level began. The level of use of mobile devices in the commercial transactions of society is now a massive number of users. It happens not only in large transactions but also in small transactions. With the community's high interest in the use of smartphone devices, this is a different opportunity to explore the potential of each village by helping the community, tiny and medium enterprises in conducting transactions, sales, and marketing online through the village government website. The village information system itself requires an e-commerce feature on its page to help small and medium enterprises in the area to sell products online through a simple page display. This research aims to design and develop new features of the village system that plays a role in the field of e-commerce with the Direct Message transaction method. The system development methodology used is Agile with Scrum as a framework. The Agile Model is a short-term development model that requires rapid adaptation and development to changes in any form. This e-commerce feature is for local communities, especially Micro, Small, and Medium Enterprises, so their products' marketing reach is even more outstanding while being recorded in the village system
Influence of Wettability and Reactivity on Refractory Degradation – Interactions of Molten Iron and Slags with Steelmaking Refractories at 1550°C
Refractories, materials that can withstand high temperatures, play an important role in the iron and steel sector which alone accounts for ~70% of total refractories produced. In this chapter, detailed wettability and interfacial phenomena investigations on alumina-carbon and zirconia-carbon refractories at steelmaking temperatures. The wettability between refractory substrates and molten iron/slags was investigated at 1550°C using the sessile drop approach in a horizontal tube furnace equipped with a CCD camera. Detailed experimental results were obtained on alumina-carbon/molten iron system at high temperatures. Alumina is known to be non-wetting to molten iron while carbon can be easily wetted. Observed contact angles were found to depend strongly on the substrate composition and contact time. While the refractory substrates containing 50 and 60% carbon were found to be non-wetting to molten iron, the substrates containing higher amounts of C (≥ 70%) were found to become increasingly wetting. Molten iron droplets were seen to spread on these substrates
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