15,556 research outputs found
Recommended from our members
The relationship between quality and economic value of fresh sweet potato and dried cassava products in Mwanza, Tanzania
This report outlines the relationship between quality and economic value for fresh sweet potato and dried cassava in the urban markets of Mwanza in north west Tanzania. These two crops form an increasingly important part of food security and, through the marketing of surpluses, of income generation for poor householders. The work reported in this report used a combination of participatory and more formal statistical methodologies in order to gauge relationships between quality and value of the marketed produce
Detection of charge motion in a non-metallic silicon isolated double quantum dot
As semiconductor device dimensions are reduced to the nanometer scale,
effects of high defect density surfaces on the transport properties become
important to the extent that the metallic character that prevails in large and
highly doped structures is lost and the use of quantum dots for charge sensing
becomes complex. Here we have investigated the mechanism behind the detection
of electron motion inside an electrically isolated double quantum dot that is
capacitively coupled to a single electron transistor, both fabricated from
highly phosphorous doped silicon wafers. Despite, the absence of a direct
charge transfer between the detector and the double dot structure, an efficient
detection is obtained. In particular, unusually large Coulomb peak shifts in
gate voltage are observed. Results are explained in terms of charge
rearrangement and the presence of inelastic cotunneling via states at the
periphery of the single electron transistor dot
High-contrast 40 Gb/s operation of a 500 um long silicon carrier-depletion slow wave modulator
This paper was published in OPTICS LETTERS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.37.003504. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law[EN] In this Letter, we demonstrate a highly efficient, compact, high-contrast and low-loss silicon slow wave modulator
based on a traveling-wave Mach¿Zehnder interferometer with two 500 μm long slow wave phase shifters. 40 Gb ∕ s
operation with 6.6 dB extinction ratio at quadrature and with an on-chip insertion loss of only 6 dB is shown. These
results confirm the benefits of slow light as a means to enhance the performance of silicon modulators based on the
plasma dispersion effect.Funding by the European Commission (EC) under project Photonics Electronics Functional Integration on CMOS (HELIOS) (FP7224312) and PROMETEO-2010- 087 R&D Excellency Program are acknowledged. F.Y.G, D.J.T. and G.T.R. acknowledge funding support
from the United Kingdom Engineering and Physical Sciences Research Council (EPSRC) under the grant “UK Silicon Photonics”.Brimont, ACJ.; Thomson, DJ.; Gardes, FY.; Fedeli, JM.; Reed, GT.; Martí Sendra, J.; Sanchis Kilders, P. (2012). High-contrast 40 Gb/s operation of a 500 um long silicon carrier-depletion slow wave modulator. Optics Letters. 37(17):3504-3506. https://doi.org/10.1364/OL.37.003504S350435063717Liao, L., Liu, A., Rubin, D., Basak, J., Chetrit, Y., Nguyen, H., … Paniccia, M. (2007). 40 Gbit/s silicon optical modulator for high-speed applications. Electronics Letters, 43(22), 1196. doi:10.1049/el:20072253Gardes, F. Y., Thomson, D. J., Emerson, N. G., & Reed, G. T. (2011). 40 Gb/s silicon photonics modulator for TE and TM polarisations. Optics Express, 19(12), 11804. doi:10.1364/oe.19.011804Thomson, D. J., Gardes, F. Y., Hu, Y., Mashanovich, G., Fournier, M., Grosse, P., … Reed, G. T. (2011). High contrast 40Gbit/s optical modulation in silicon. Optics Express, 19(12), 11507. doi:10.1364/oe.19.011507Brimont, A., Thomson, D. J., Sanchis, P., Herrera, J., Gardes, F. Y., Fedeli, J. M., … Martí, J. (2011). High speed silicon electro-optical modulators enhanced via slow light propagation. Optics Express, 19(21), 20876. doi:10.1364/oe.19.020876Ziebell, M., Marris-Morini, D., Rasigade, G., Fédéli, J.-M., Crozat, P., Cassan, E., … Vivien, L. (2012). 40 Gbit/s low-loss silicon optical modulator based on a pipin diode. Optics Express, 20(10), 10591. doi:10.1364/oe.20.010591Dong, P., Chen, L., & Chen, Y. (2012). High-speed low-voltage single-drive push-pull silicon Mach-Zehnder modulators. Optics Express, 20(6), 6163. doi:10.1364/oe.20.006163Taylor, H. F. (1999). Enhanced electrooptic modulation efficiency utilizing slow-wave optical propagation. Journal of Lightwave Technology, 17(10), 1875-1883. doi:10.1109/50.793770O’Faolain, L., Beggs, D. M., White, T. P., Kampfrath, T., Kuipers, K., & Krauss, T. F. (2010). Compact Optical Switches and Modulators Based on Dispersion Engineered Photonic Crystals. IEEE Photonics Journal, 2(3), 404-414. doi:10.1109/jphot.2010.2047918Brimont, A., Vicente Galán, J., Maria Escalante, J., Martí, J., & Sanchis, P. (2010). Group-index engineering in silicon corrugated waveguides. Optics Letters, 35(16), 2708. doi:10.1364/ol.35.002708Soref, R., & Bennett, B. (1987). Electrooptical effects in silicon. IEEE Journal of Quantum Electronics, 23(1), 123-129. doi:10.1109/jqe.1987.1073206Nguyen, H. C., Sakai, Y., Shinkawa, M., Ishikura, N., & Baba, T. (2011). 10 Gb/s operation of photonic crystal silicon optical modulators. Optics Express, 19(14), 13000. doi:10.1364/oe.19.013000Dong, P., Liao, S., Liang, H., Qian, W., Wang, X., Shafiiha, R., … Asghari, M. (2010). High-speed and compact silicon modulator based on a racetrack resonator with a 1 V drive voltage. Optics Letters, 35(19), 3246. doi:10.1364/ol.35.00324
Sampling properties of directed networks
For many real-world networks only a small "sampled" version of the original
network may be investigated; those results are then used to draw conclusions
about the actual system. Variants of breadth-first search (BFS) sampling, which
are based on epidemic processes, are widely used. Although it is well
established that BFS sampling fails, in most cases, to capture the
IN-component(s) of directed networks, a description of the effects of BFS
sampling on other topological properties are all but absent from the
literature. To systematically study the effects of sampling biases on directed
networks, we compare BFS sampling to random sampling on complete large-scale
directed networks. We present new results and a thorough analysis of the
topological properties of seven different complete directed networks (prior to
sampling), including three versions of Wikipedia, three different sources of
sampled World Wide Web data, and an Internet-based social network. We detail
the differences that sampling method and coverage can make to the structural
properties of sampled versions of these seven networks. Most notably, we find
that sampling method and coverage affect both the bow-tie structure, as well as
the number and structure of strongly connected components in sampled networks.
In addition, at low sampling coverage (i.e. less than 40%), the values of
average degree, variance of out-degree, degree auto-correlation, and link
reciprocity are overestimated by 30% or more in BFS-sampled networks, and only
attain values within 10% of the corresponding values in the complete networks
when sampling coverage is in excess of 65%. These results may cause us to
rethink what we know about the structure, function, and evolution of real-world
directed networks.Comment: 21 pages, 11 figure
Liver Abscess Severity at Slaughter Does Not Affect Meat Tenderness and Sensory Attributes in Commercially Finished Beef Cattle Fed Without Tylosin Phosphate
Liver abscesses are a significant problem in the United States’ cattle feeding industry, costing the industry an estimated $15.9 million annually in liver condemnation, trim losses, and reduced carcass weights and quality grades. Recent reported incidence rates of liver abscesses at slaughter range from 10 to 20%. Liver abscess incidence may be influenced by a number of factors including: breed, gender, diet, days on feed, cattle type, season, and geographical location. Liver abscesses typically occur secondary to rumen insults caused by acidosis or rumenitis. It has been proposed that pathogens associated with liver abscess formation enter the blood stream through damaged rumen epithelium and are transported to the liver through the portal vein where they cause infection, manifested as liver abscesses. Severe liver abscesses have been linked to reduction in hot carcass weight, dressing percentage, yield grade, longissimus muscle area, and marbling scores of carcasses when compared to those with normal livers. However, the effect of liver abscesses on meat tenderness and sensory attributes has not been previously investigated
Community pharmacist clinical portal enabled access to aspects of patients' primary and secondary care EHR: exploring the general public's views in NHS Tayside.
Background and Objective: Community pharmacist access to aspects of patients' primary and secondary care electronic healthcare records (EHR) was piloted in NHS Tayside, Scotland. While policy makers and pharmacists are largely in favour of community pharmacist access, and there is an unmet service need based on GP workforce-workload evidence, the general public's perspectives of pharmacist EHR access had yet to be explored in Scotland. Objective: to determine the general public's perspectives of community pharmacist EHR access in NHS Tayside. Design: A survey methodology using paper-based questionnaires posted to a random sample of the general public in NHS Tayside (March-May 2017). Quantitative data were analysed using descriptive statistics (IBM SPSS version_21_). The study was approved by university Ethical Review Committee. Results: Of 1000 surveys distributed, 205 returned, (27 undeliverable), providing a response rate of 21%. Although some were unsure (23%; n = 47/203), most indicated their community pharmacist would be better able to recognise problems with medicines/healthcare given access to patients' EHR (63%; n = 127/203), knew why each medicine was prescribed (74%; n = 150/203), and thought that a long-term condition would make access to patient records essential (73%; n = 148/203). Few respondents were against/were non-committal on community pharmacists having read or read-and-write access to EHR. For example, the Emergency Care Summary (ECS) (13%; n = 27/201) where, if access were permitted, respondents preferred that consent should not be required on each and every occasion: ECS (73%; n = 148/203). Many felt access to patients' EHR would mean the pharmacist was better informed so could provide better care (68%; n = 136/200) and that mistakes were less likely to happen (71%; n = 142/200). Conclusion: Findings from this survey recognised community pharmacists could contribute more to improving patient care and safety, as part of the wider healthcare team, if they were better informed through access to patients' EHR. Enabling treatment of common clinical conditions in community pharmacy brings benefits to patients while reducing pressure on GP appointments. While there remain areas of uncertainty, and this is a small albeit representative sample from one area in Scotland, this study demonstrates support for community pharmacist access to patients' EHR with a preference for a simplified consent process
Tidal dissipation in rotating giant planets
[Abridged] Tides may play an important role in determining the observed
distributions of mass, orbital period, and eccentricity of the extrasolar
planets. In addition, tidal interactions between giant planets in the solar
system and their moons are thought to be responsible for the orbital migration
of the satellites, leading to their capture into resonant configurations. We
treat the underlying fluid dynamical problem with the aim of determining the
efficiency of tidal dissipation in gaseous giant planets. In cases of interest,
the tidal forcing frequencies are comparable to the spin frequency of the
planet but small compared to its dynamical frequency. We therefore study the
linearized response of a slowly and possibly differentially rotating planet to
low-frequency tidal forcing. Convective regions of the planet support inertial
waves, while any radiative regions support generalized Hough waves. We present
illustrative numerical calculations of the tidal dissipation rate and argue
that inertial waves provide a natural avenue for efficient tidal dissipation in
most cases of interest. The resulting value of Q depends in a highly erratic
way on the forcing frequency, but we provide evidence that the relevant
frequency-averaged dissipation rate may be asymptotically independent of the
viscosity in the limit of small Ekman number. In short-period extrasolar
planets, if the stellar irradiation of the planet leads to the formation of a
radiative outer layer that supports generalized Hough modes, the tidal
dissipation rate can be enhanced through the excitation and damping of these
waves. These dissipative mechanisms offer a promising explanation of the
historical evolution and current state of the Galilean satellites as well as
the observed circularization of the orbits of short-period extrasolar planets.Comment: 74 pages, 12 figures, submitted to The Astrophysical Journa
- …