545 research outputs found
Fundamental Forces and Scalar Field Dynamics in the Early Universe
Scalar weak gravity conjectures (SWGCs) attempt to pinpoint the ranges of
couplings consistent with a fundamental theory of all interactions. We identify
a generic dynamical consequence of these conjectures for cosmology and show
that SWGCs imply a particular behavior of the scalar fields in the early
universe. A scalar field that develops a large expectation value during
inflation must relax to the minimum of effective potential at a later time.
SWGCs imply that a homogeneous distribution of the field is unstable with
respect to fragmentation into localized lumps, which could potentially lead to
significant consequences for cosmology.Comment: 6 pages, 1 figure; v2: publication versio
Foreshadowing of Performance Accuracy by Event-Related Potentials: Evidence from a Minimal-Conflict Task
Recent studies employing stimulus-response compatibility tasks suggest that an increase in the amplitude of the positive deflection of the response-locked event-related potential (ERP) foreshadows errors on forthcoming trials. However, no studies have tested the generalizability of error-foreshadowing positivity to tasks without stimulus-response interference.The present study adopted an alternating-response task, in which the participants responded to the pointing direction of an arrowhead (up or down). Although the arrowhead direction alternated for the majority of trials (95%), occasionally this pattern was broken by a repeated stimulus, termed a lure trial. We compared the matched-reaction-time correct-preceding ERP with the error-preceding ERP on lure-preceding trials. There was no evidence that errors are foreshadowed by the increase of a positive electroencephalogram (EEG) deflection. To the contrary, analyses of ERPs time-locked to electromyogram (EMG) onset on the five consecutive lure-preceding trials showed larger positive deflections on correct-preceding than error-preceding trials. The post-response negativity did not differ between correct-preceding and error-preceding trials.These results suggest that in minimal conflict tasks a decreased positivity may foreshadow incorrect performance several trials prior to the error, possibly reflecting the waning of task-related efforts. Therefore, error-foreshadowing brain signals may be task-specific
バングラデシュ ノ ジョウケン フリチイキ ニ オケル ノウギョウ ケンキュウ カイハツ : ノウギョウ セイサン タヨウカ ト ギジュツ イテン
The main focus of this study is on research and developmental approaches with regard to agricultural diversification and transfer of technology to small scale farmers in the less favored areas in Bangladesh. Agriculture is an important part of the Bangladesh economy, with about 80% of people living in rural areas, which accounts for 65% of the labor force engaged in agriculture. Under the existing land tenure system, the majority of economic participants in the agricultural sector are small scale farmers. They produce many forms of crop.livestock integration which vary according to different socio .economic needs. Family farming is characterized by relatively low production rates because of factors such as climate, soil condition, crop varieties, irrigation, breeding, feeding, diseases and management. Thus, the research and development of agricultural diversification can play a significant role in meeting people\u27s nutritional needs, alleviating severe nutrient deficiencies. After the independence of Bangladesh, a non.governmental organization from North America, MCC (Mennonite Central Committee) has been working since 1972 to conduct research in generating agricultural technologies and to make them available to the marginal and below marginal farm families in the less favored area in south Bangladesh. Afterwards, from 1988, as a sub.program of MCC Agriculture Program, Partnership in Agriculture Research and Extension (PARE) was started to work with local NGOs in the less favored areas in central and north Bangladesh, with the objective to build their capacity in establishing agricultural components for their beneficiaries. Probably in recognition of the importance of that goal, international NGOs have provided funding to MCC for the implementation of the PARE Program in order to : 1) Provide skill training to partner NGO staff, 2) Assist NGO staff in conducting training for their beneficiaries, 3) Conduct demonstrations, 4) Conduct on.farm trials, 5) Organize field days, 6) Involve beneficiaries in undertaking agricultural projects, 7) Develop networking and linkages with government institutions through organizing workshops and seminars. It will be good model for the agricultural transfer of technology to small scale farmers in other developing countries
Zonal wavenumber diagnosis of Rossby-wave-like oscillations using paired ground-based radars
Free traveling Rossby wave normal modes (RNMs) are often investigated through large‐scale space‐time spectral analyses, which therefore is subject to observational availability, especially in the mesosphere. Ground‐based mesospheric observations were broadly used to identify RNMs mostly according to the periods of RNMs without resolving their horizontal scales. The current study diagnoses zonal wave numbers of RNM‐like oscillations occurring in mesospheric winds observed by two meteor radars at about 79°N. We explore four winters comprising the major stratospheric sudden warming events (SSWs) 2009, 2010, and 2013. Diagnosed are predominant oscillations at the periods of 10 and 16 days lasting mostly for three to five whole cycles. All dominant oscillations are associated with westward zonal wave number m=1, excepting one 16‐day oscillation associated with m=2. We discuss the m=1 oscillations as transient RNMs and the m=2 oscillation as a secondary wave of nonlinear interaction between an RNM and a stationary Rossby wave. All the oscillations occur around onsets of the three SSWs, suggesting associations between RNMs and SSWs. For comparison, we also explore the wind collected by a similar network at 54°N during 2012–2016. Explored is a manifestation of 5‐day wave, namely, an oscillation at 5–7 days with m=1), around the onset of SSW 2013, supporting the associations between RNMs and SSWs
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ZonalWave Number Diagnosis of RossbyWave-Like Oscillations Using Paired Ground-Based Radars
Free traveling Rossby wave normal modes (RNMs) are often investigated through large-scale space-time spectral analyses, which therefore is subject to observational availability, especially in the mesosphere. Ground-based mesospheric observations were broadly used to identify RNMs mostly according to the periods of RNMs without resolving their horizontal scales. The current study diagnoses zonal wave numbers of RNM-like oscillations occurring in mesospheric winds observed by two meteor radars at about 79°N. We explore four winters comprising the major stratospheric sudden warming events (SSWs) 2009, 2010, and 2013. Diagnosed are predominant oscillations at the periods of 10 and 16 days lasting mostly for three to five whole cycles. All dominant oscillations are associated with westward zonal wave number m=1, excepting one 16-day oscillation associated with m=2. We discuss the m=1 oscillations as transient RNMs and the m=2 oscillation as a secondary wave of nonlinear interaction between an RNM and a stationary Rossby wave. All the oscillations occur around onsets of the three SSWs, suggesting associations between RNMs and SSWs. For comparison, we also explore the wind collected by a similar network at 54°N during 2012–2016. Explored is a manifestation of 5-day wave, namely, an oscillation at 5–7 days with m=1), around the onset of SSW 2013, supporting the associations between RNMs and SSWs. ©2020. The Authors
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