Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

GIBBERELLIC-ACID AND THE INHIBITION OF AERIAL TUBERIZATION IN SOLANUM-TUBEROSUM-L

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Adaptation strategies to counter climate change impact on sheep

Climate change has proved to impose potential negative effects on species survival, ecosystems stability and sustainable livestock production around the globe. Among the various environmental factors, heat stress is well known for its harmful effects on livestock and related production losses. Sheep exposed to heat stress show lower body growth and hide quality and compromised reproductive functions in both males and females. Adapting to the changing climate requires appropriate manipulations in the production system by taking into account the positive effects and attempting to diminish the negative effects of climate change. The highly adapted indigenous breeds identified by marker-assisted selection can be used as an efficient tool for developing thermotolerant breeds through improved breeding programmes. Promotion of such breeds can improve production efficiency and may lead to fewer greenhouse gas emissions. Further, the local people, especially women, are good managers of natural resources and possess excellent skills to utilize the natural resources efficiently. Hence, occasional training and a participatory research approach into the roles of women assist the tackling of climate change in the rural areas. In addition, well-organized early warning systems avoid severe damage due to unexpected disasters by providing sufficient time to prepare effective responses. Development of skilled disease surveillance supported with effective health services may effectively control the spread of climate change-related diseases in sheep. Furthermore, the production system requires improved water resource management to provide sufficient water for sheep production in the arid and semi-arid regions. Cultivation of drought-tolerant fodder varieties in extremely hot areas is an efficient adaptive strategy to ensure sufficient supply of feed during scarcity periods. Finally, strengthening extension services and building awareness through capacity-building programmes helps the livestock keepers to improve their adaptive capacities against climate change. Adaptation strategies related to cold stress include advanced cold-tolerant breeding programmes, migration in extreme winter and adoption of proper cold management practices. According to the predictions by various international bodies, the consequences of climate change will be on the rise in the future. Hence, adequate cost-effective management strategies appear to be the immediate need of the hour for adapting sheep production systems to the changing climate