Over the past decade, long-duration γ-ray bursts (GRBs)-including the subclass of X-ray flashes (XRFs)-have been revealed to be a rare variety of type Ibc supernova. Although all these events result ...from the death of massive stars, the electromagnetic luminosities of GRBs and XRFs exceed those of ordinary type Ibc supernovae by many orders of magnitude. The essential physical process that causes a dying star to produce a GRB or XRF, and not just a supernova, is still unknown. Here we report radio and X-ray observations of XRF 060218 (associated with supernova SN 2006aj), the second-nearest GRB identified until now. We show that this event is a hundred times less energetic but ten times more common than cosmological GRBs. Moreover, it is distinguished from ordinary type Ibc supernovae by the presence of 1048 erg coupled to mildly relativistic ejecta, along with a central engine (an accretion-fed, rapidly rotating compact source) that produces X-rays for weeks after the explosion. This suggests that the production of relativistic ejecta is the key physical distinction between GRBs or XRFs and ordinary supernovae, while the nature of the central engine (black hole or magnetar) may distinguish typical bursts from low-luminosity, spherical events like XRF 060218.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
Catfish is currently the flagship commodity to increase economic value in Indonesia. Catfish farming is very profitable because good broodstock maintenance will produce quality tillers. A ...good catfish broodstock should have a feed management system, thereby improving the quality of mains. The purpose is to learn about feed management technology (life and pellet feed) on the maintenance of Mutiara catfish (
Clarias
sp.). The method is with a descriptive method with immediate data retrieval and secondary data. Life feed is observed by taking water samples and then observed using a microscope. Life feed that is found using a microscope is
Spirulina
sp. and
Chlorella
sp. Feed management on the maintenance of the broodstock of the Mutiara catfish (
Clarias
sp.) is by feeding one time a day at a dose of 1.5 kg, the feed used is pellets PL 1 size 2 mm which has 33% protein and 5% fat, FCR which can be 2.43, absolute growth 15.42 kg, SGR 0.147 %, GR 2.4 gram/day, and SR 100%. Fish enlargement is a business activity maintenance fish up to the size of consumption. The feed is the largest component on the business of catfish enlargement.
Surface chlorophyll-a (chl-a) variation in the Southeastern Tropical Indian Ocean (SETIO) shows different patterns in response to the various types of the Indian Ocean Dipole (IOD) events. Thirteen ...years of remotely sensed surface chl-a data from the Moderate-resolution Imaging Spectroradiometer (MODIS) were used to evaluate interannual surface chl-a variation in the SETIO. During the period of analysis (January 2003-December 2015), there were three canonical positive IOD (pIOD) and four pIOD Modoki events. It is found that the spatial patterns of surface chl-a variation were coherent with the pattern of surface wind anomaly, and the sea surface temperature anomaly (SSTA). During canonical pIOD events, high chl-a concentrations were observed in the vicinity of the Sunda Strait and along the coast of western tip of the Java Island around the Cilacap region. Meanwhile, during pIOD Modoki event, surface chl-a concentration was relatively higher and distributed wider than those observed during canonical pIOD event. The analysis shows that relatively weak upwelling event indicated by a deep isothermal layer depth (ILD) during pIOD Modoki events combined with thin barrier layer thickness (BLT) and deep mixed layer provides a favourable condition for an increase in surface chl-a in the SETIO region. Meanwhile, strong upwelling as indicated by shallow ILD combined with thick BLT and shallow mixed layer prevents surface chl-a to increase during canonical pIOD events.
Over the past decade, our physical understanding of gamma-ray bursts (GRBs) has progressed rapidly, thanks to the discovery and observation of their long-lived afterglow emission. Long-duration (> 2 ...s) GRBs are associated with the explosive deaths of massive stars ('collapsars', ref. 1), which produce accompanying supernovae; the short-duration (< or = 2 s) GRBs have a different origin, which has been argued to be the merger of two compact objects. Here we report optical observations of GRB 060614 (duration approximately 100 s, ref. 10) that rule out the presence of an associated supernova. This would seem to require a new explosive process: either a massive collapsar that powers a GRB without any associated supernova, or a new type of 'engine', as long-lived as the collapsar but without a massive star. We also show that the properties of the host galaxy (redshift z = 0.125) distinguish it from other long-duration GRB hosts and suggest that an entirely new type of GRB progenitor may be required.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Although forest edges have been studied extensively as an important consequence of fragmentation, a unifying theory of edge influence has yet to be developed. Our objective was to take steps toward ...the development of such a theory by (1) synthesizing the current knowledge of patterns of forest structure and composition at anthropogenically created forest edges, (2) developing hypotheses about the magnitude and distance of edge influence that consider the ecological processes influencing these patterns, and (3) identifying needs for future research. We compiled data from 44 published studies on edge influence on forest structure and composition in boreal, temperate, and tropical forests. Abiotic and biotic gradients near created forest edges generate a set of primary responses to edge creation. Indirect effects from these primary responses and the original edge gradient perpetuate edge influence, leading to secondary responses. Further changes in vegetation affect the edge environment, resulting in ongoing edge dynamics. We suggest that the magnitude and distance of edge influence are a direct function of the contrast in structure and composition between adjacent communities on either side of the edge. Local factors such as climate, edge characteristics, stand attributes, and biotic factors affect patch contrast. Regional factors define the context within which to assess the ecological significance of edge influence (the degree to which the edge habitat differs from interior forest habitat). Our hypotheses will help predict edge influence on structure and composition in forested ecosystems, an important consideration for conservation. For future research on forest edges in fragmented landscapes, we encourage the testing of our hypotheses, the use of standardized methodology, complete descriptions of study sites, studies on other types of edges, synthesis of edge influence on different components of the ecosystem, and investigations of edges in a landscape context.
Past studies have suggested that long-duration γ-ray bursts have a 'standard' energy of Eγ 1051 erg in the ultra-relativistic ejecta, after correcting for asymmetries in the explosion ('jets'). But a ...group of sub-energetic bursts, including the peculiar GRB980425 associated with the supernova SN1998bw (Eγ 1048 erg), has recently been identified. Here we report radio observations of GRB030329 that allow us to undertake calorimetry of the explosion. Our data require a two-component explosion: a narrow (5° opening angle) ultra-relativistic component responsible for the γ-rays and early afterglow, and a wide, mildly relativistic component that produces the radio and optical afterglow more than 1.5 days after the explosion. The total energy release, which is dominated by the wide component, is similar to that of other γ-ray bursts, but the contribution of the γ-rays is energetically minor. Given the firm link of GRB030329 with SN2003dh, our result indicates a common origin for cosmic explosions in which, for reasons not yet understood, the energy in the highest-velocity ejecta is extremely variable.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
On 2006 May 5, a 4 s duration, low-energy, similar to 10 super(49) erg, gamma-ray burst (GRB) was observed, spatially associated with a z = 0.0804 galaxy. Here we report the discovery of the GRB ...optical afterglow and observations of its environment using Gemini South, the Hubble Space Telescope (HST), Chandra, Swift, and the Very Large Array. The optical afterglow of this GRB is spatially associated with a prominent star-forming region in the Sc-type galaxy 2dFGRS S173Z112. Its proximity to a star-forming region suggests that the progenitor delay time, from birth to explosion, is smaller than similar to 10 Myr. Our HST deep imaging rules out the presence of a supernova brighter than an absolute magnitude of about -11 (or -12.6 in the case of maximal extinction) at about 2 weeks after the burst and limits the ejected mass of radioactive super(56)Ni to be less than about 2 x 10 super(-4) M unk (assuming no extinction). Although it was suggested that GRB 060505 may belong to a new class of long-duration GRBs with no supernova, we argue that the simplest interpretation is that the physical mechanism responsible for this burst is the same as that for short-duration GRBs.
SUMMARYTukong is the rumpless indigenous chicken breed of Indonesia. Its features must be described as the basis for their preservation and improvement. The current understanding of the Tukong, ...including its origin, exterior traits, and production indicators, is presented in this review. As a result, the chicken feather colour varies from greenish-black, reddish-black, bluish-black, brown, and white, with a red pea-shaped comb. The Tukong is a dual-purpose breed categorised as a small-sized bird with a body weight of 1.65 ± 0.82 kg (rooster) and 1.42 ± 0.55 kg (a hen). This breed has the potential to be developed as a meat-producing chicken, which is supported by its high dressing percentage (79.50%). However, the Tukong has low reproduction properties (egg production = 8–14 eggs/6 month period, fertility = 73.51%, hatchability = 81.42–84.26%). The development of the Tukong chicken needs to be increased in order to maintain its sustainability and take advantage of its superiority to other pilot candidates for the formation of new breeds.
The area of peatland in Indonesia reaches 13 million hectares, around 12.37%, 1.67 million hectares, used for plantations. Around 700 to 800 thousand ha are used for oil palm plantations, with a ...productivity of 20-25 tons / ha / year, this value is no less than that of other types of land. The purpose of this study was to analyze the social and economic impacts of oil palm plantation development, analyze the financial feasibility of cultivation on peat and non-peat lands and analyze the sustainable management model of oil palm plantations. The results of this study, the development of oil palm plantations has a positive impact on economic and social conditions. Social problems arose between the company and the community in the management of oil palm plantations when the government issued a moratorium on permits for the opening of oil palm plantations on peatland due to fire. The exploitation of oil palm on peatlands has lower benefits compared to mineral land. Management of oil palm plantations can be carried out on peatlands, but it is necessary to consider water regulation so that oil palm plantations are sustainable on peatland because peatlands are easily damaged land.
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