Genetic Parameters of Common Wheat in Nepal

Knowledge on variation within traits and their genetics are prerequisites in crop improvement program. Thus, in present paper we aimed to estimate genetic and environmental indices of common wheat genotypes. For the purpose, eight quantitative traits were measured from 30 wheat genotypes, which were in randomized complete block design with 3 replicates. Components of variance and covariance were estimated along with heritability, genetic gain, realized heritability, coheritability and correlated response. Differences between phenotypic and genotypic variances in heading days, maturity days and plant height were not large. Grain yield and plant height showed the highest phenotypic (18.189%) and genotypic (12.06%) coefficient of variances, respectively. Phenotypic covariance was higher than genotypic and environmental covariance in most of the traits. The highest heritability and realized heritability were of heading days followed by maturity days. Genetic gain for plant height was the highest. Co-heritability of 1000-grain weight with tillers number was the highest. The highest correlated response was expressed by grain yield with tillers number. This study indicates the possibility of improving wheat genotypes through selection utilizing existing variation in these traits.Journal of Nepal Agricultural Research Council Vol.1 2015 pp.9-1

Emotional arousal impairs association-memory: roles of amygdala and hippocampus

Emotional arousal is well-known to enhance memory for individual items or events, whereas it can impair association memory. The neural mechanism of this association memory impairment by emotion is not known: In response to emotionally arousing information, amygdala activity may interfere with hippocampal associative encoding (e.g., via prefrontal cortex). Alternatively, emotional information may be harder to unitize, resulting in reduced availability of extra-hippocampal medial temporal lobe support for emotional than neutral associations. To test these opposing hypotheses, we compared neural processes underlying successful and unsuccessful encoding of emotional and neutral associations. Participants intentionally studied pairs of neutral and negative pictures (Experiments 1–3). We found reduced association-memory for negative pictures in all experiments, accompanied by item-memory increases in Experiment 2. High-resolution fMRI (Experiment 3) indicated that reductions in associative encoding of emotional information are localizable to an area in ventral-lateral amygdala, driven by attentional/salience effects in the central amygdala. Hippocampal activity was similar during both pair types, but a left hippocampal cluster related to successful encoding was observed only for negative pairs. Extra-hippocampal associative memory processes (e.g., unitization) were more effective for neutral than emotional materials. Our findings suggest that reduced emotional association memory is accompanied by increases in activity and functional coupling within the amygdala. This did not disrupt hippocampal association-memory processes, which indeed were critical for successful emotional association memory formation

Reduced associative memory for negative information: impact of confidence and interactive imagery during study

Although item-memory for emotional information is enhanced, memory for associations between items is often impaired for negative, emotionally arousing compared to neutral information. We tested two possible mechanisms underlying this impairment, using picture pairs: 1) higher confidence in one’s own ability to memorise negative information may cause participants to under-study negative pairs; 2) better interactive imagery for neutral pairs could facilitate associative memory for neutral pairs more than for negative pairs. Tested with associative recognition, we replicated the impairment of associative memory for negative pairs. We also replicated the result that confidence in future memory (judgments of learning) was higher for negative than neutral pairs. Inflated confidence could not explain the impairment of associative recognition memory: Judgements of learning were positively correlated with associative memory success for both negative and neutral pairs. However, neutral pairs were rated higher in their conduciveness to interactive imagery than negative pairs, and this difference in interactive imagery showed a robust relationship to the associative memory difference. Thus, associative memory reductions for negative information are not due to differences in encoding effort. Instead, interactive imagery may be less effective for encoding of negative than neutral pairs

High reward makes items easier to remember, but harder to bind to a new temporal context

Learning through reward is central to adaptive behavior. Indeed, items are remembered better if they are experienced while participants expect a reward, and people can deliberately prioritize memory for high- over low-valued items. Do memory advantages for high-valued items only emerge after deliberate prioritization in encoding? Or, do reward-based memory enhancements also apply to unrewarded memory tests and to implicit memory? First, we tested for a high-value memory advantage in unrewarded implicit- and explicit-tests (Experiment 1). Participants first learned high or low-reward values of 36 words, followed by unrewarded lexical decision and free-recall tests. High-value words were judged faster in lexical decision, and more often recalled in free recall. These two memory advantages for high-value words were negatively correlated suggesting at least two mechanisms by which reward value can influence later item-memorability. The ease with which the values were originally acquired explained the negative correlation: people who learned values earlier showed reward effects in implicit memory whereas people who learned values later showed reward effects in explicit memory. We then asked whether a high-value advantage would persist if trained items were linked to a new context (Experiments 2a and 2b). Following the same value training as in Experiment 1, participants learned lists composed of previously trained words mixed with new words, each followed by free recall. Thus, participants had to retrieve words only from the most recent list, irrespective of their values. High- and low-value words were recalled equally, but low-value words were recalled earlier than high-value words and high-value words were more often intruded (proactive interference). Thus, the high-value advantage holds for implicit- and explicit-memory, but comes with a side effect: High-value items are more difficult to relearn in a new context. Similar to emotional arousal, reward value can both enhance and impair memory

Efficient pricing of ratchet equity-indexed annuities in a variance-gamma economy

In this paper we propose a new method for approximating the price of arithmetic Asian options in a Variance-Gamma (VG) economy, which is then applied to the problem of pricing equityindexed annuity contracts. The proposed procedure is an extension to the case of a VG-based model of the moment-matching method developed by Turnbull and Wakeman and Levy for the pricing of this class of path-dependent options in the traditional Black-Scholes setting. The accuracy of the approximation is analyzed against RQMC estimates for the case of ratchet equityindexed annuities with index averaging

From attosecond to zeptosecond coherent control of free-electron wave functions using semi-infinite light fields

Light-electron interaction in empty space is the seminal ingredient for free-electron lasers and also for controlling electron beams to dynamically investigate materials and molecules. Pushing the coherent control of free electrons by light to unexplored timescales, below the attosecond, would enable unprecedented applications in light-assisted electron quantum circuits and diagnostics at extremely small timescales, such as those governing intramolecular electronic motion and nuclear phenomena. We experimentally demonstrate attosecond coherent manipulation of the electron wave function in a transmission electron microscope, and show that it can be pushed down to the zeptosecond regime with existing technology. We make a relativistic pulsed electron beam interact in free space with an appropriately synthesized semi-infinite light field generated by two femtosecond laser pulses reflected at the surface of a mirror and delayed by fractions of the optical cycle. The amplitude and phase of the resulting coherent oscillations of the electron states in energymomentum space are mapped via momentum-resolved ultrafast electron energy-loss spectroscopy. The experimental results are in full agreement with our theoretical framework for light-electron interaction, which predicts access to the zeptosecond timescale by combining semi-infinite X-ray fields with free electrons.Comment: 22 pages, 6 figure

Comparing multidrug-resistant tuberculosis patient costs under molecular diagnostic algorithms in South Africa

SETTING: Ten primary health care facilities in Cape Town, South Africa, 2010–2013. OBJECTIVE: A comparison of costs incurred by patients in GenoType® MDRTBplus line-probe assay (LPA) and Xpert® MTB/RIF-based diagnostic algorithms from symptom onset until treatment initiation for multidrug-resistant tuberculosis (MDR-TB). METHODS: Eligible patients identified from laboratory and facility records were interviewed 3–6 months after treatment initiation and a cost questionnaire completed. Direct and indirect costs, individual and household income, loss of individual income and change in household income were recorded in local currency, adjusted to 2013 costs and converted to $US. RESULTS: Median number of visits to initiation of MDR-TB treatment was reduced from 20 to 7 (P < 0.001) and median costs fell from US$68.1 to US$38.3 (P = 0.004) in the Xpert group. From symptom onset to being interviewed, the proportion of unemployed increased from 39% to 73% in the LPA group (P < 0.001) and from 53% to 89% in the Xpert group (P < 0.001). Median household income decreased by 16% in the LPA group and by 13% in the Xpert group. CONCLUSION: The introduction of an Xpert-based algorithm brought relief by reducing the costs incurred by patients, but loss of employment and income persist. Patients require support to mitigate this impact

Rheology of Active-Particle Suspensions

We study the interplay of activity, order and flow through a set of coarse-grained equations governing the hydrodynamic velocity, concentration and stress fields in a suspension of active, energy-dissipating particles. We make several predictions for the rheology of such systems, which can be tested on bacterial suspensions, cell extracts with motors and filaments, or artificial machines in a fluid. The phenomena of cytoplasmic streaming, elastotaxis and active mechanosensing find natural explanations within our model.Comment: 3 eps figures, submitted to Phys Rev Let