Model independent evaluation of the Wilson coefficient of the Weinberg operator in QCD

We derive a Wilson coefficient of a CP-violating purely gluonic dimension-6 operator called the Weinberg operator ($GG\tilde{G}$) generated by a scalar and two fermions at the two-loop level. We do not specify the representation of SU(3)$_c$ for the scalar and the fermions, and thus our result can be applied to a variety of models beyond the standard model. We estimate the nucleon EDMs induced by the Weinberg operator in some examples and discuss the importance of measuring EDMs. It is found that future measurements of the EDMs can probe physics at higher energy scale beyond the reach of collider experiments.Comment: 22 pages, 7 figures; v2: version accepted by JHEP; v3: Eq. (4.2) is added, Table 1 is extende

Horizontally Transferred Genetic Elements in the Tsetse Fly Genome: An Alignment-Free Clustering Approach Using Batch Learning Self-Organising Map (BLSOM)

Tsetse flies (Glossina spp.) are the primary vectors of trypanosomes, which can cause human and animal African trypanosomiasis in Sub-Saharan African countries. The objective of this study was to explore the genome of Glossina morsitans morsitans for evidence of horizontal gene transfer (HGT) from microorganisms. We employed an alignment-free clustering method, that is, batch learning self-organising map (BLSOM), in which sequence fragments are clustered based on the similarity of oligonucleotide frequencies independently of sequence homology. After an initial scan of HGT events using BLSOM, we identified 3.8% of the tsetse fly genome as HGT candidates. The predicted donors of these HGT candidates included known symbionts, such as Wolbachia, as well as bacteria that have not previously been associated with the tsetse fly. We detected HGT candidates from diverse bacteria such as Bacillus and Flavobacteria, suggesting a past association between these taxa. Functional annotation revealed that the HGT candidates encoded loci in various functional pathways, such as metabolic and antibiotic biosynthesis pathways. These findings provide a basis for understanding the coevolutionary history of the tsetse fly and its microbes and establish the effectiveness of BLSOM for the detection of HGT events

Farming strategy of African smallholder farmers in transition from traditional to alternative agriculture : the case of the Nupe in central Nigeria

It is worthwhile to understand farming strategies of smallholder farmers in sub-Saharan Africa, especially those of farmers who are in transition from traditional to alternative agriculture in terms of adoption of innovative technologies. In a case study of inland valleys in central Nigeria, we investigated the farming strategy of Nupe farmers who have a long-term tradition of wet rice cultivation and indigenous methods of land preparation for soil, water and weed management. In this region, a new method of land preparation has recently been introduced along with a recommendation to use improved seeds and chemical fertilizers. Our findings reveal that Nupe farmers directly sow traditional seeds and apply a marginal amount of fertilizer to paddy plots prepared by labor-saving methods on drought-prone hydromorphic valley fringes and flood-susceptible valley bottoms, whereas they preferentially transplanted improved seedlings and applied a relatively large quantity of fertilizer to paddy fields prepared by a labor-intensive and mechanized method on a valley position where they can access to optimum water condition (less risky against the drought and flood)

Prior Emission Model for X-ray Plateau Phase of Gamma-Ray Burst Afterglows

The two-component emission model to explain the plateau phase of the X-ray afterglows of gamma-ray bursts (GRBs) is proposed. One component, which is responsible for the plateau and subsequent normal decay phase of the X-ray afterglow, is the prior emission via outflow ejected from the central engine before the main burst. The other is the main outflow, which causes the prompt GRB emission and the initial steep decay phase of the X-ray afterglow. In this model, the transition from the plateau to the subsequent normal decay phase is an artifact of the choice of the zero of time. For events with distinct plateau phase, the central engine is active 10^3-10^4 sec before the launch of the main outflow. According to this model, a prior emission in the X-ray and/or optical bands 10^3-10^4 sec before the prompt GRB emission is possibly seen, which will be tested by near-future instruments such as Monitor of All-sky X-ray Image (MAXI), WIDe-field telescope for GRB Early Timing (WIDGET), and so on.Comment: 12 pages, 2 figures, ApJL in pres

T cell receptor (TCR)-induced death of immature CD4<SUP>+</SUP>CD8<SUP>+</SUP> thymocytes by two distinct mechanisms differing in their requirement for CD28 costimulation: implications for negative selection in the thymus

Negative selection is the process by which the developing lymphocyte receptor repertoire rids itself of autoreactive specificities. One mechanism of negative selection in developing T cells is the induction of apoptosis in immature CD4+CD8+ (DP) thymocytes, referred to as clonal deletion. Clonal deletion is necessarily T cell receptor (TCR) specific, but TCR signals alone are not lethal to purified DP thymocytes. Here, we identify two distinct mechanisms by which TCR-specific death of DP thymocytes can be induced. One mechanism requires simultaneous TCR and costimulatory signals initiated by CD28. The other mechanism is initiated by TCR signals in the absence of simultaneous costimulatory signals and is mediated by subsequent interaction with antigen-presenting cells. We propose that these mechanisms represent two distinct clonal deletion strategies that are differentially implemented during development depending on whether immature thymocytes encounter antigen in the thymic cortex or thymic medulla