Implications of the Visible and X-Ray Counterparts to GRB970228

The gamma-ray burst source GRB970228 has been observed after a delay of 8--12 hours in X-rays and after one day in visible and near infrared light. This marks the first detection of emission at lower frequencies following the gamma-ray observation of a GRB and the first detection of any visible counterpart to a GRB. We consider possible delayed visible and X-ray emission mechanisms, and conclude that the intrinsic gamma-ray activity continued at a much reduced intensity for at least a day. There are hints of such continued activity in other GRB, and future observations can decide if this is true of GRB in general. The observed multi-band spectrum of GRB970228 agrees with the predictions of relativistic shock theory when the flux is integrated over a time longer than that required for a radiating electron to lose its energy.Comment: 5 pp., tex, 1 figur

Membangun Server Multicast Berbasis Streaming Menggunakan Centos

The development of IP-based technology contribute to the development of telecomunication and information technology.  One of  IP-based technology application is streaming multicast, as part of broadcasting. The streaming  process is made by accessing  Telkom-2 broadcast  through AKATEL LAN network, then  server forward it to clients using multicast IP system. Multicast IP is D-class IP, which is able to send data package in realtime. In multicast system, server only send one data package to  some clients with same speed transmition. The Telkom-2 broadcast is already accessed before   sent as data package. Server will access Telkom-2 broadcast using parabola antenna and Hughes modem, then forward it to clients through AKATEL LAN network. Clients must conect to server via AKATEL LAN network and already  instaled VLC player, in order to be able to access the Telkom-2 broadcas

Sintesis 3-(4-bromofenil)-1-(naftalen-1-il)prop-2-en-1-on dari 1-asetilnaftalen dengan 4-bromobenzaldehid

Chalcone of 3-(4-Bromo-phenyl)-1-naphthalen-1-yl-propenone was synthesizedby the stirring method in Claisen-Schmidt Condensation with NaOH as the catalyst. Thestructure of the compound was confirmed by 1 H-NMR, 13 C-NMR, IR, MS, and UVspectroscopy method. The compound produced was in 81.9% yields. Datacharacterization showed that the compound obtained was the targetted compound

Possible Evidence for Relativistic Shocks in Gamma-Ray Bursts

Relativistic shock models of gamma-ray bursts may be tested by comparison of their predicted low energy asymptotic spectral indices s to observations. Synchrotron radiation theory predicts that the instantaneous spectrum has s = - 1/3 and the spectrum integrated over the radiative decay of the electrons' energies has s = 1/2, with other cases lying between these limits. We examine the spectra of 11 bursts obtained by the Large Area Detectors on BATSE. One agrees with the predicted instantaneous spectrum, as does the initial portion of a second, and three are close to the predicted integrated spectrum. All the observed asymptotic spectral slopes lie in the predicted range. This evidence for relativistic shocks is independent of detailed models of bursts and of assumptions about their distances. Radiation observed with the predicted instantaneous spectrum has a comparatively smooth time dependence, consistent with the necessarily long radiation time, while that with the predicted integrated spectrum has a spiky time dependence, consistent with the necessarily short radiation time.Comment: 12 pp., latex, 16 figure

Analisis Efisiensi Pemasaran Jagung di Provinsi Nusa Tenggara Barat

Maize is one of important agricultural commodity which can be used for food and feed. However, the marketing of this commodity still inefisient. The purpose of this research is to analyze marketing efficiency of maize of West Nusa Tenggara Province via marketing channel, market structure, market behavior, market performance and marketing strategy. Sampling was conducted by simple random sampling and the number of sample used is 30 people. The method used is SCP analysis that consists of margin, price-share, market integration and marketing mix. The result shows marketing inefficiency presence, where 48.66 percent of farmers use second channel, to sell directly to wholesalers. Market structure tendency is oligopsony, where the wholesalers influence price. The margin distribution among the three channels are differs. Vertical market integration is strong in the short and long run, but only on wholesaler level. Marketing strategy on wholesaler level could not increase marketing efficiency due to the homogenous nature of product sold, dry shelled corn. The price is determined by quality and production cost. Promotion done via words of mouth and most sellers choose to sell along the main road although fifty percent of them live in the countryside

Spectra and Light Curves of GRB Afterglows

We performed accurate numerical calculations of angle-, time-, and frequency-dependent radiative transfer for the relativistic motion of matter in gamma-ray burst (GRB) models. Our technique for solving the transfer equation, which is based on the method of characteristics, can be applied to the motion of matter with a Lorentz factor up to 1000. The effect of synchrotron self-absorption is taken into account. We computed the spectra and light curves from electrons with a power-law energy distribution in an expanding relativistic shock and compare them with available analytic estimates. The behavior of the optical afterglows from GRB 990510 and GRB 000301c is discussed qualitatively.Comment: 8 pages, 7 figure

Yet Another Model of Gamma-Ray Bursts

Sari and Piran have demonstrated that the time structure of gamma-ray bursts must reflect the time structure of their energy release. A model which satisfies this condition uses the electrodynamic emission of energy by the magnetized rotating ring of dense matter left by neutron star coalescence; GRB are essentially fast, high field, differentially rotating pulsars. The energy densities are large enough that the power appears as an outflowing equilibrium pair plasma, which produces the burst by baryon entrainment and subsequent internal shocks. I estimate the magnetic field and characteristic time scale for its rearrangement, which determines the observed time structure of the burst. There may be quasi-periodic oscillations at the rotational frequencies, which are predicted to range up to 5770 Hz (in a local frame). This model is one of a general class of electrodynamic accretion models which includes the Blandford and Lovelace model of AGN, and which can also be applied to black hole X-ray sources of stellar mass. The apparent efficiency of nonthermal particle acceleration is predicted to be 10--50%, but higher values are possible if the underlying accretion flow is super-Eddington. Applications to high energy gamma-ray observations of AGN are briefly discussed.Comment: 21pp, latex, uses aaspp4.st

Gonadal Development of Domesticated Coral Trout (Plectropomus Leopardus) Reared in Floating Net Cage

Research on Coral trout breeding has been started since 2002 at the Institute of Mariculture Research and Development and currently some hatcheries are being developed around the institute using natural broodstock. To promote the success on this breeding program, it is necessary to study the reproduction development of domesticated coral trout. The fishes were reared in floating net cage. Observation were conducted on 163 fishes in June 2013 with body weight range from 710 -2020 g (average of 1.393 g) and total length with range of 34-49.5 cm. Fishes were dissected and taken out their gonad for histology preparedness. Histology analyses found that there were 156 female, 2 hermaprodite, 2 male, and 3 unidentified fishes. All female fishes were on early gonadal development (stage I and II with gonadal maturation index of observed coral trout ranged from 0.1 to 1.83). Further analyses showed that several different stages of gonad were found in the same gonad and concluded that coral trout was multiple spawnning order (asynchrounous). Based on the data above, it was concluded that gonad maturation of Coral trout is able to develop in domestication system in floating net cage

Membangun Remaja Sehat Untuk Mewujudkan Pribadi Yang Berakhlak Mulia

Parents have a vital role for growth and development of a teenager. Parents as the first actor to be an example for a teenager, so it must equip children with knowledge of the personality and the science of religion that later children can socialize in the community. Juvenile delinquency is happening is not the fault of the parents themselves, but also lies in the surrounding environment that can affect the behavior of adolescent youth. The role of parents and the environment is important for teens to form personal the better. In dealing with teenagers there are some things you should always keep in mind, namely that the soul is a soul-filled adolescent turmoil. Internal and external conditions are equally turbulent adolescence that causes more prone than other stages of mental development of adolescents. To reduce collisions between turbulence and to provide opportunities for youth to develop themselves in a more optimal, need to be created nearby environmental conditions as stable as possible, especially the family environment