518 research outputs found
Sustainable development of smallholder crop-livestock farming in developing countries
Meeting the growing demand for animal-sourced food, prompted by population growth and increases in average per-capita income in low-income countries, is a major challenge. Yet, it also presents significant potential for agricultural growth, economic development, and reduction of poverty in rural areas. The main constraints to livestock producers taking advantage of growing markets include; lack of forage and feed gaps, communal land tenure, limited access to land and water resources, weak institutions, poor infrastructure and environmental degradation. To improve rural livelihood and food security in smallholder crop-livestock farming systems, concurrent work is required to address issues regarding efficiency of production, risk within systems and development of whole value chain systems. This paper provides a review of several forage basedstudies in tropical and non-tropical dry areas of the developing countries. A central tenet of this paper is that forages have an essential role in agricultural productivity, environmental sustainability and livestock nutrition in smallholder mixed farming systems
Mitigating Off-Policy Bias in Actor-Critic Methods with One-Step Q-learning: A Novel Correction Approach
Compared to on-policy counterparts, off-policy model-free deep reinforcement
learning can improve data efficiency by repeatedly using the previously
gathered data. However, off-policy learning becomes challenging when the
discrepancy between the underlying distributions of the agent's policy and
collected data increases. Although the well-studied importance sampling and
off-policy policy gradient techniques were proposed to compensate for this
discrepancy, they usually require a collection of long trajectories and induce
additional problems such as vanishing/exploding gradients or discarding many
useful experiences, which eventually increases the computational complexity.
Moreover, their generalization to either continuous action domains or policies
approximated by deterministic deep neural networks is strictly limited. To
overcome these limitations, we introduce a novel policy similarity measure to
mitigate the effects of such discrepancy in continuous control. Our method
offers an adequate single-step off-policy correction that is applicable to
deterministic policy networks. Theoretical and empirical studies demonstrate
that it can achieve a "safe" off-policy learning and substantially improve the
state-of-the-art by attaining higher returns in fewer steps than the competing
methods through an effective schedule of the learning rate in Q-learning and
policy optimization
Pulsed Beam Tests at the SANAEM RFQ Beamline
A proton beamline consisting of an inductively coupled plasma (ICP) source,
two solenoid magnets, two steerer magnets and a radio frequency quadrupole
(RFQ) is developed at the Turkish Atomic Energy Authority's (TAEA) Saraykoy
Nuclear Research and Training Center (SNRTC-SANAEM) in Ankara. In Q4 of 2016,
the RFQ was installed in the beamline. The high power tests of the RF power
supply and the RF transmission line were done successfully. The high power RF
conditioning of the RFQ was performed recently. The 13.56 MHz ICP source was
tested in two different conditions, CW and pulsed. The characterization of the
proton beam was done with ACCTs, Faraday cups and a pepper-pot emittance meter.
Beam transverse emittance was measured in between the two solenoids of the
LEBT. The measured beam is then reconstructed at the entrance of the RFQ by
using computer simulations to determine the optimum solenoid currents for
acceptance matching of the beam. This paper will introduce the pulsed beam test
results at the SANAEM RFQ beamline. In addition, the high power RF conditioning
of the RFQ will be discussed.Comment: 6 pages, 6 figures. Proceedings of the International Particle
Accelerator Conference 2017 (IPAC'17), May 14-19, 2017, TUPAB015, p. 134
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Examining the Mediating Role of Organisational Support on the Relationship between Organisational Cynicism and Turnover Intention in Technology Firms in Istanbul
Cynicism and turnover intentions are highlighted as being detrimental to organisations' sustainability. Drawing on the social exchange theory, this paper aims to examine the effect of organisational cynicism on turnover intention and the mediating role of organisational support on this relationship. A survey was conducted with 289 employees and managers. Data were gathered from 54 technology firms from Istanbul, Turkey, and analysed through structural equation modelling using AMOS. The findings suggest that the cognitive and affective dimensions of cynicism are significant predictors of turnover intention, and further that organisational support mediates the relationship between the cognitive and affective dimensions of cynicism and turnover intention. This research is novel in that it deepens our understanding of how detrimental workplace perceptions might affect employees' intentions to leave their organisations and to what extent organisational support mediates this relationship in technology firms in Istanbul, Turkey. To our knowledge, no study has investigated these three variables together, as in the proposed model
The effects of community interventions on unplanned healthcare use in patients with multimorbidity: a systematic review
OBJECTIVES: To summarise the impact of community-based interventions for multimorbid patients on unplanned healthcare use. The prevalence of multimorbidity (co-existence of multiple chronic conditions) is rapidly increasing and affects one-third of the global population. Patients with multimorbidity have complex healthcare needs and greater unplanned healthcare usage. Community-based interventions allow for continued care of patients outside hospitals, but few studies have explored the effects of these interventions on unplanned healthcare usage. DESIGN: A systematic review was conducted. MEDLINE, EMBASE, PsychINFO and Cochrane Library online databases were searched. Studies were screened and underwent risk of bias assessment. Data were synthesised using narrative synthesis. SETTING: Community-based interventions. PARTICIPANTS: Patients with multimorbidity. MAIN OUTCOME MEASURES: Unplanned healthcare usage. RESULTS: Thirteen studies, including a total of 6148 participants, were included. All included studies came from high-income settings and had elderly populations. All studies measured emergency department attendances as their primary outcome. Risk of bias was generally low. Most community interventions were multifaceted with emphasis on education, self-monitoring of symptoms and regular follow-ups. Four studies looked at improved care coordination, advance care planning and palliative care. All 13 studies found a decrease in emergency department visits post-intervention with risk reduction ranging from 0 (95% confidencec interval [CI]: -0.37 to 0.37) to 0.735 (95% CI: 0.688-0.785). CONCLUSIONS: Community-based interventions have potential to reduce emergency department visits in patients with multimorbidity. Identification of specific successful components of interventions was challenging given the overlaps between interventions. Policymakers should recognise the importance of community interventions and aim to integrate aspects of these into existing healthcare structures. Future research should investigate the impact of such interventions with broader participant characteristics
Global changes in the proteome of Cupriavidus necator H16 during poly-(3-hydroxybutyrate) synthesis from various biodiesel by-product substrates
Additional file 1: Table S1. P-scores of proteomic runs of C. necator H16 grown with different substrates
Prevalence of Coccidian Species in the Water Buffalo (Bubalus Bubalis) in the Province of Afyon, Turkey
Realistic modelling of quantum point contacts subject to high magnetic fields and with current bias at out of linear response regime
The electron and current density distributions in the close proximity of
quantum point contacts (QPCs) are investigated. A three dimensional Poisson
equation is solved self-consistently to obtain the electron density and
potential profile in the absence of an external magnetic field for gate and
etching defined devices. We observe the surface charges and their apparent
effect on the confinement potential, when considering the (deeply) etched QPCs.
In the presence of an external magnetic field, we investigate the formation of
the incompressible strips and their influence on the current distribution both
in the linear response and out of linear response regime. A spatial asymmetry
of the current carrying incompressible strips, induced by the large source
drain voltages, is reported for such devices in the non-linear regime.Comment: 16 Pages, 9 Figures, submitted to PR
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