1,192 research outputs found
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Country Debt Default Probabilities in Emerging Markets: Were Credit Rating Agencies Wrong?
This chapter contains sections titled: Debt Rescheduling Probability Model; Empirical Versus CRAs' Probabilities of Emerging Markets Sovereign Debt Rescheduling; Implications
Cross Pixel Optical Flow Similarity for Self-Supervised Learning
We propose a novel method for learning convolutional neural image
representations without manual supervision. We use motion cues in the form of
optical flow, to supervise representations of static images. The obvious
approach of training a network to predict flow from a single image can be
needlessly difficult due to intrinsic ambiguities in this prediction task. We
instead propose a much simpler learning goal: embed pixels such that the
similarity between their embeddings matches that between their optical flow
vectors. At test time, the learned deep network can be used without access to
video or flow information and transferred to tasks such as image
classification, detection, and segmentation. Our method, which significantly
simplifies previous attempts at using motion for self-supervision, achieves
state-of-the-art results in self-supervision using motion cues, competitive
results for self-supervision in general, and is overall state of the art in
self-supervised pretraining for semantic image segmentation, as demonstrated on
standard benchmarks
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What impact does a change of fund manager have on mutual fund performance?
Using a unique database of UK fund manager changes over the period from 1997 to 2011, we examine the impact of such changes on fund performance. We find clear evidence to suggest that a manager change does affect the benchmark-adjusted performance of UK mutual funds. In particular we find a significant deterioration in the benchmark-adjusted returns of funds that were top performers before the manager exit and, conversely, a significant improvement in the average benchmark-adjusted returns of funds that were poor performers before the manager exit. Our use of the Carhart's (1997) four-factor model reveals that the improvement in average post manager exit performance is accompanied by a reduction in market risk, a slight reduction in exposure to small cap stocks, and an increase in exposure to value and momentum stocks. Overall, our results suggest that UK fund management companies have been relatively successful in replacing bad managers with better managers, but relatively unsuccessful at finding equivalent replacements for their top performing managers. We believe that regulators should therefore try to ensure that all efforts are made by fund management companies to inform all of their investors about a change in management
Irrigation scheduling based on Crop Water Stress Index (CWSI) for cool and warm-season turf grass under subsurface-drip irrigation method
Aims: This study was conducted to determine irrigation scheduling basedon the Crop Water Stress Index (CWSI) of cool (CS) and warm-season (WS)turfgrass species under subsurface-drip irrigation method.Methods and Results: The field experiment was carried out during thesummer period of 2018 in the Agricultural Production and Research Centre(TURAM) of Silivri municipality, Istanbul-Turkey. Specific objectives wereto measure actual evapotranspiration (ETc) values for both turfgrass types,to compare their responses to different water levels, to determine CWSIvalues for both turfgrass species under different irrigation scheduling andopportunity of using CWSI in irrigation timing, to compare ETc withreference to evapotranspiration (ETo) calculated with five differentmethods and to determine crop coefficient curve (kc) for experimentalconditions, and to focus on the crop growing and irrigation managementparameters under subsurface-drip irrigation method. Three irrigationstrategies [I1:30%, I2:50%, and I3:70%) were tested in a split-plotrandomized complete block design with three replications. Thesestrategies corresponded, respectively, to 30%, 50% and 70% of totalavailable soil moisture depletion at 0-30 cm of the effective root zone andreturning soil moisture back to field capacity. The results indicated thatcolour, quality, fresh yield, dry matter yield, irrigation water use efficiency,water use efficiency, vegetation height and mowing were significantlydifferent in terms of irrigation strategies for both species. The mostappropriate irrigation strategies were I2:50% for CS and I3:70% for WSturfgrass which corresponded to a CWSI of 0.47 and 0.45, respectively.Conclusions: The amount of applied irrigation water in WS turfgrass was53% less than in CS turfgrass. Actual evapotranspiration was 26% lower forWS than for CS turfgrass.Significance and Impact of the Study: These results obtained from theexperiments will help choosing of turf type and irrigation scheduling tosave water in urban areas
Prior expectation mediates neural adaptation to repeated sounds in the auditory cortex: An MEG study
Contains fulltext :
99626.pdf (publisher's version ) (Open Access)Repetition suppression, the phenomenon that the second presentation of a stimulus attenuates neural activity, is typically viewed as an automatic consequence of repeated stimulus presentation. However, a recent neuroimaging study has suggested that repetition suppression may be driven by top-down expectations. Here we examined whether and when repetition suppression can be modulated by top-down expectation. Participants listened to auditory stimuli in blocks where tone repetitions were either expected or unexpected, while we recorded ongoing neural activity using magnetoencephalography. We found robust repetition suppression in the auditory cortex for repeated tones. Interestingly, this reduction was significantly larger for expected than unexpected repetitions, both in terms of evoked activity and gamma-band synchrony. These findings indicate a role of top-down expectation in generating repetition suppression and are in line with predictive coding models of perception, in which the difference between expected and actual input is propagated from lower to higher cortical areas.6 p
Level of physical activity in patients with osteoporosis
Objectives: The aim of this research was to examine the degree and types of physical activity (heavy physical activity, medium heavy and light physical activity) in female patients with lower bone mineral density compared to healthy women.
Materials and Methods: The cross-sectional study included 40 female patients (65,85±11,46 yrs) with lower bone mineral density (BMD) and 20 patients (56,25±6,6 yrs) with no existing abnormality of BMD levels. The research was conducted at the Medical Rehabilitation Clinic, Clinical Center of Vojvodina. Data were collected using the internationally endorsed questionnaire IPAQ. BMD was measured at lumbar spine (L1-4) and at proximal femur by Dual X-ray Absorptiometry technique (DXA). Osteoporosis was defined as BMD > -2.5 T score.
Results: We found that subjects with a normal bone mineral density had the highest level of physical activity (MET = 3154.58), followed by subjects with osteopenia (MET = 2311.25). Patients suffering from osteoporosis who were physically active had the lowest value of MET (1972.95) (p˂0.01). Sub-analysis based on BMI categories showed 10% (2 patients) of those with osteopenia were underweight, compared to 40% (8 patients) in the group with osteoporosis. Conclusions: Patients with osteoporosis were more obese and less physically active, as compared to healthier females. Our findings support the fact that adapted physical activity seems to be important for the prevention and treatment of patients with osteoporosis
Managing transition to electrical and autonomous vehicles
Constant innovation within automotive industry created more safe, ecological and affordable vehicles. This industry is now facing significant changes created by the introduction of electrical powertrains and autonomous vehicle technologies, as well. These technologies reached a level of development which makes feasible their widespread deployment. This may provide significant social benefits by improving safety and saving lives, reducing fuel consumption, congestion and pollution, improving mobility and land use. The transition from traditional vehicles to autonomous and electrical vehicles is driven by convergence of connectivity, electrification and changing customer needs. The main objective of the investigation, presented in this paper, was to explore various aspects of this paradigm shift, highlight potential benefits, technological changes and policy recommendations
Inmunización contra babesiosis bovina con vacunas a base de parásitos vivos.
Con el objetivo de evaluar varios sistemas de inmunización contra babesiosis bovina con vacunas a base de organismos vivos, se utilizaron 40 terneros Holstein. Con 2 métodos se produjo la inmunidad: sangre de terneros portadores de B. bigemina y B. argentina, y sangre de animales esplenectomizados inoculado con B. bigemina y B. argentina, recolectada en el momento de sufrir la enfermedad. El grado de resistencia se midió por exposición natural a garrapatas infectadas en una zona endémica de Colombia. El ganado premunizado demostró un alto grado de resistencia contra babesiosis comparado con el grupo control no premunizado, el cual fue necesario tratar para prevenir mortalidad. La respuesta a la vacunación fue mucho mejor en ganado inmunizado con organismos obtenidos de un ternero esplenectomizado infectado que contenía sangre de animales portadores. Se comparó la ganancia de peso de animales vacunados con no vacunados: hubo una ligera disminución de peso en el grupo vacunado 2 meses después de la vacunación, pero una vez los animales se expusieron al campo, el grupo control disminuyó notoriamiente de peso, siendo la diferencia promedio a los 6 meses de 53 kg a favor del grupo vacunado. En la práctica, los programas orientados a conocer el comportamiento de animales vacunados, debe dirigirse a lograr el control de babesiosis y anaplasmosis conjuntamente, ya que estas enfermedades se presentan en Colombia en forma concurrenteGanado de leche-Ganadería lech
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