277 research outputs found
Improving Information and Performance in Grain Marketing: an Assessment of Current Market Information Systems, and Recommendations for Developing a Public Grain MIS
This paper focuses on one dimension which is at the core of all modern economies: how to provide private and public agents with timely and accurate information regarding current and expected future market conditions. Its objective is to show the need for a public market information system for agricultural markets in Ethiopia, and to present concrete proposals that can be reviewed, debated, and modified as necessary by the relevant Ethiopian authorities in collaboration with Food Security Research Project (FSRP) personnel.food security, food policy, Crop Production/Industries, Marketing, Q18,
Dos cents cinquanta anys d'ets i uts de l'Hospital de Pobres de la vila de Tossa: un vincle entre Tossa i Calonge
Analysis of different vibration patterns to guide blind people
[EN] The literature indicates the best vibration positions and frequencies on the human body where tactile information is transmitted. However, there is a lack of knowledge about how to combine tactile stimuli for navigation. The aim of this study is to compare different vibration patterns outputted to blind people and to determine the most intuitive vibration patterns to indicate direction for navigation purposes through a tactile belt. The vibration patterns that stimulate the front side of the waist are preferred for indicating direction. Vibration patterns applied on the back side of the waist could be suitable for sending messages such as stop.This research is supported by Seventh European Framework Programme (FP7/2007-2013) under grant agreement 605821 (BLINDTRACK). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.DurĂĄ-Gil, JV.; Bazuelo-Ruiz, B.; Moro PĂ©rez, D.; Molla Domenech, F. (2017). Analysis of different vibration patterns to guide blind people. PeerJ. 5:1-10. https://doi.org/10.7717/peerj.30821105Cholewiak, R. W. (1999). The Perception of Tactile Distance: Influences of Body Site, Space, and Time. Perception, 28(7), 851-875. doi:10.1068/p2873Cholewiak, R. W., Brill, J. C., & Schwab, A. (2004). Vibrotactile localization on the abdomen: Effects of place and space. Perception & Psychophysics, 66(6), 970-987. doi:10.3758/bf03194989Cholewiak, R. W., & Craig, J. C. (1984). Vibrotactile pattern recognition and discrimination at several body sites. Perception & Psychophysics, 35(6), 503-514. doi:10.3758/bf03205946Faugloire, E., & Lejeune, L. (2014). Evaluation of heading performance with vibrotactile guidance: The benefits of informationâmovement coupling compared with spatial language. Journal of Experimental Psychology: Applied, 20(4), 397-410. doi:10.1037/xap0000032Ghiani, G., Leporini, B., & PaternĂČ, F. (2009). Vibrotactile feedback to aid blind users of mobile guides. Journal of Visual Languages & Computing, 20(5), 305-317. doi:10.1016/j.jvlc.2009.07.004Johnson, L. A., & Higgins, C. M. (2006). A Navigation Aid for the Blind Using Tactile-Visual Sensory Substitution. 2006 International Conference of the IEEE Engineering in Medicine and Biology Society. doi:10.1109/iembs.2006.259473KĂ€rcher, S. M., Fenzlaff, S., Hartmann, D., Nagel, S. K., & König, P. (2012). Sensory Augmentation for the Blind. Frontiers in Human Neuroscience, 6. doi:10.3389/fnhum.2012.00037Marston, J. R., Loomis, J. M., Klatzky, R. L., Golledge, R. G., & Smith, E. L. (2006). Evaluation of spatial displays for navigation without sight. ACM Transactions on Applied Perception, 3(2), 110-124. doi:10.1145/1141897.1141900Ranjbar, P., & Stenström, I. (2013). Monitor, a Vibrotactile Aid for Environmental Perception: A Field Evaluation by Four People with Severe Hearing and Vision Impairment. The Scientific World Journal, 2013, 1-11. doi:10.1155/2013/206734Saaty, T. L. (1990). How to make a decision: The analytic hierarchy process. European Journal of Operational Research, 48(1), 9-26. doi:10.1016/0377-2217(90)90057-iSrikulwong, M., & OâNeill, E. (2010). A Comparison of Two Wearable Tactile Interfaces with a Complementary Display in Two Orientations. Lecture Notes in Computer Science, 139-148. doi:10.1007/978-3-642-15841-4_15Van Erp, J. B. F. (2008). Absolute localization of vibrotactile stimuli on the torso. Perception & Psychophysics, 70(6), 1016-1023. doi:10.3758/pp.70.6.101
A SLAM-based augmented reality app for the assessment of spatial short-term memory using visual and auditory stimuli
A SLAM-based Augmented Reality (AR) app has been designed, developed, and validated to assess spatial short-term memory. Our app can be used with visual and auditory stimuli and can run on mobile devices. It can be used in any indoor environment. The anchors and data of the app are persistently stored in the cloud. As an authoring tool, the type of stimulus, its number, and specific positions in the real environment can be customized for each session. A study involving 48 participants was carried out to analyze the performance outcomes comparing the location and remembering of stimuli in a real environment using visual versus auditory stimuli. The number of objects placed correctly was similar for the two different stimuli used. However, the group that used the auditory stimulus spent significantly more time completing the task and required significantly more attempts. The performance outcomes were independent of age and gender. For the auditory stimuli, correlations among all of the variables of the AR app and the variables of two other tasks (object-recall and map-pointing) were found. We also found that the greater the number of correctly placed auditory stimuli, the greater the perceived competence and the less mental effort required. The greater the number of errors, the less the perceived competence. Finally, the auditory stimuli are valid stimuli that may benefit the assessment of the memorization of spatial-auditory associations, but the memorization of spatial-visual associations is dominant, as our results suggest
Role of Cellular Lipids in Positive-Sense RNA Virus Replication Complex Assembly and Function
Positive-sense RNA viruses are responsible for frequent and often devastating diseases in humans, animals, and plants. However, the development of effective vaccines and anti-viral therapies targeted towards these pathogens has been hindered by an incomplete understanding of the molecular mechanisms involved in viral replication. One common feature of all positive-sense RNA viruses is the manipulation of host intracellular membranes for the assembly of functional viral RNA replication complexes. This review will discuss the interplay between cellular membranes and positive-sense RNA virus replication, and will focus specifically on the potential structural and functional roles for cellular lipids in this process
New bio-polymeric membranes composed of alginate-carrageenan to be applied as polymer electrolyte membranes for DMFC
Novel polyelectrolyte membranes were prepared from pure solutions of alginate (Alg), carrageenan (Car) and their mixtures. The films were crosslinked and sulfonated and then, characterized by several techniques: ionic exchange capacity (IEC), water uptake, mechanical thermal properties, and also functional properties such as methanol permeability and proton conductivity. The results show that Alg/Car membranes have a ductile behavior. Low carrageenan concentrations have a weak thermoprotective effect, which slightly delays both Tg and Tm of prepared membranes. The methanol permeability of Alg/Car membranes increase with the carrageenan content varying from 0.55 Ă 10â6 cm2 sâ1 for Alg/Car 100/00 to 4.89 Ă 10â6 cm2 sâ1 for Alg/Car 80/20. The Proton conductivities of the membranes increase with the carrageenan content from 9.79 Ă 10â3 S cmâ1 for Alg/Car 100/00 until 3.16 Ă 10â2 S cmâ1 for Alg/Car 80/20 at 90 °C. Finally the proton transfer mechanism is discussed in terms of the conductivity activation energy and the dependence of the proton diffusion coefficient with the temperature has been studied.Fil: Pasini Cabello, Sergio David. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico San Luis. Instituto de FĂsica Aplicada; ArgentinaFil: Molla, S.. Universidad Politecnica de Valencia; EspañaFil: Ochoa, Nelio Ariel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico San Luis. Instituto de FĂsica Aplicada; ArgentinaFil: Marchese, Jose. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico San Luis. Instituto de FĂsica Aplicada; ArgentinaFil: Gimenez, E.. Universidad Politecnica de Valencia; EspañaFil: Compan, V.. Universidad Politecnica de Valencia; Españ
An unbiased assessment of the role of imprinted genes in an intergenerational model of developmental programming.
Environmental factors during early life are critical for the later metabolic health of the individual and of future progeny. In our obesogenic environment, it is of great socioeconomic importance to investigate the mechanisms that contribute to the risk of metabolic ill health. Imprinted genes, a class of functionally mono-allelic genes critical for early growth and metabolic axis development, have been proposed to be uniquely susceptible to environmental change. Furthermore, it has also been suggested that perturbation of the epigenetic reprogramming of imprinting control regions (ICRs) may play a role in phenotypic heritability following early life insults. Alternatively, the presence of multiple layers of epigenetic regulation may in fact protect imprinted genes from such perturbation. Unbiased investigation of these alternative hypotheses requires assessment of imprinted gene expression in the context of the response of the whole transcriptome to environmental assault. We therefore analyse the role of imprinted genes in multiple tissues in two affected generations of an established murine model of the developmental origins of health and disease using microarrays and quantitative RT-PCR. We demonstrate that, despite the functional mono-allelicism of imprinted genes and their unique mechanisms of epigenetic dosage control, imprinted genes as a class are neither more susceptible nor protected from expression perturbation induced by maternal undernutrition in either the F1 or the F2 generation compared to other genes. Nor do we find any evidence that the epigenetic reprogramming of ICRs in the germline is susceptible to nutritional restriction. However, we propose that those imprinted genes that are affected may play important roles in the foetal response to undernutrition and potentially its long-term sequelae. We suggest that recently described instances of dosage regulation by relaxation of imprinting are rare and likely to be highly regulated
Complete genome sequence of Treponema pallidum ssp. pallidum strain SS14 determined with oligonucleotide arrays
<p>Abstract</p> <p>Background</p> <p>Syphilis spirochete <it>Treponema pallidum </it>ssp. <it>pallidum </it>remains the enigmatic pathogen, since no virulence factors have been identified and the pathogenesis of the disease is poorly understood. Increasing rates of new syphilis cases per year have been observed recently.</p> <p>Results</p> <p>The genome of the SS14 strain was sequenced to high accuracy by an oligonucleotide array strategy requiring hybridization to only three arrays (Comparative Genome Sequencing, CGS). Gaps in the resulting sequence were filled with targeted dideoxy-terminators (DDT) sequencing and the sequence was confirmed by whole genome fingerprinting (WGF). When compared to the Nichols strain, 327 single nucleotide substitutions (224 transitions, 103 transversions), 14 deletions, and 18 insertions were found. On the proteome level, the highest frequency of amino acid-altering substitution polymorphisms was in novel genes, while the lowest was in housekeeping genes, as expected by their evolutionary conservation. Evidence was also found for hypervariable regions and multiple regions showing intrastrain heterogeneity in the <it>T. pallidum </it>chromosome.</p> <p>Conclusion</p> <p>The observed genetic changes do not have influence on the ability of <it>Treponema pallidum </it>to cause syphilitic infection, since both SS14 and Nichols are virulent in rabbit. However, this is the first assessment of the degree of variation between the two syphilis pathogens and paves the way for phylogenetic studies of this fascinating organism.</p
An Oxygen Abundance Gradient into the Outer Disk of M81
The extended HI disk and tidal tails of M81 present an interesting
environment to study the effects of galaxy interaction on star formation and
chemical evolution of the outer disk of a large spiral galaxy. We present
H{\alpha} imaging of the outer disk of M81 and luminosities for 40 HII regions
out to about 3 times the optical radius. We have also obtained MMT spectra for
21 HII regions out to more than twice the optical radius. We derive strong line
oxygen abundances for all HII regions using R_{23} based and [NII]/[OII] based
calibrations and electron temperature abundances for seven regions spanning a
galactocentric distance between 5.7 and 32 kpc. We also comment on the
abundances of HII regions near KDG 61 and the "tidal dwarf" candidate HoIX. Our
results constitute the most radially extended metallicity study for M81 to
date. With this extended data set, we find an overall oxygen abundance gradient
of -0.013 dex/kpc over the entire radial range. This is significantly flatter
than what has been found in previous studies which were limited to the optical
disk. From our temperature based abundances, we find a gradient of -0.020
dex/kpc and present the possibility of a broken gradient from these data, but
note the need to obtain more temperature based abundances at intermediate
galactocentric distances (~10-20 kpc) to verify whether or not this may be the
case. We discuss our main result of a rather flat gradient for M81 in the
context of simulations and observations of abundance gradients in other
galaxies. We find that the shallow abundance gradient of M81 is likely a result
of the interaction history of this galaxy.Comment: 41 pages, 11 figures, accepted for publication in MNRA
Study of lymphoedema of non-filarial origin in the north west region of Cameroon: spatial distribution, profiling of cases and socio-economic aspects of podoconiosis
Background:
Although podoconiosis is endemic in Cameroon, little is known about its epidemiology and spatial distribution.
Methods:
In this cross-sectional, population-based study, we enrolled all adults (â„15 years) residing in the districts of North-West Region of Cameroon for more than 10 or more years. Participants were interviewed, had physical examination. The study outcomes were prevalence estimates lymphoedema and podoconiosis. House-to-house screening was conducted by Community Health Implementers (CHIs). CHIs registered all individuals with lymphoedema and collected additional individual and household-related information. A panel of experts re-examined and validated all lymphoedema cases registered by CHIs.
Results:
Of the 439,781 individuals registered, 214,195 were adults (â„15 years old) and had lived in the districts of the Region for more than 10 years. A total of 2,143 lymphoedema cases, were identified by CHIs, giving a prevalence of lymphoedema 1.0% (95% confidence interval [CI]; 0.96-1.04) (2,143/214,195). After review by experts, podoconiosis prevalence in the study area was 0.48% (1,049/214,195) (95% CI; 0.46-0.52). The prevalence of podoconiosis varied by health district, from 0.16% in Oku to 1.92% in Bafut (p < 0.05). A total of 374 patients were recruited by stratified random sampling from the validated CHIsâ register to assess the clinical features and socio-economic aspects of the disease. Patients reportedly said to have first noticed swelling at an average age of 41.9 ± 19.1 (range: 6-90 years). Most patients (86.1%) complained of their legs suddenly becoming hot, red and painful. The majority (309, 96.5%) of the interviewees said they had worn shoes occasionally at some point in their life. The reportedly mean age at first shoe wearing was 14.2 ± 10.1 (± Standard Deviation), range (1-77 years). A high proportion (82.8%) of the participants wore shoes at the time of interview. Of those wearing shoes, only 67 (21.7%) were wearing protective shoes.
Conclusion:
This study provides insight into the geographical distribution and epidemiology of podoconiosis in the North West region of Cameroon, yet management is limited. Evidence-informed targeted interventions are needed to manage people with lymphoedem
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