High Energy Emission from the Prompt Gamma-Ray Burst

We study the synchrotron and synchrotron self-Compton (SSC) emission from internal shocks that are responsible for the prompt gamma-ray emission in GRBs, and consider the relation between these two components, taking into account the high energy (HE) cutoff due to pair production and Thomson scattering. We find that in order for the peak energy of the synchrotron to be E_p\sim 300 keV with a variability time t_v>1 ms, a Lorentz factor \Gamma<350 is needed, implying no HE emission above \sim 30 MeV and the synchrotron component would dominate at all energies. If we want both E_p\sim 300 keV and prompt HE emission up to 2 GeV, as detected by EGRET for GRB 940217, we need \Gamma\sim 600 and t_v\sim 0.1 ms, which might be resolved by super AGILE. If such prompt HE emission is common in GRBs, as may be tested by GLAST, then for t_v\gtrsim 1 ms we need \Gamma\gtrsim 350, which implies E_p\lesssim 100 keV. Therefore if X-ray flashes are GRBs with high values of t_v and \Gamma, they should produce \gtrsim 1 GeV emission. For an electron power law index p>2, the SSC component dominates the emission above 100 MeV. Future observations by GLAST may help determine the value of p and whether the HE emission is consistent with a single power law (one component--the synchrotron, dominates) or has a break where the \nuF_\nu slope turns from negative to positive, implying that the SSC component becomes dominant above \sim 100 MeV. The HE emission is expected to show similar variability and time structure to that of the soft gamma-ray emission. Finally, we find that in order to see delayed HE emission from the prompt GRB due to pair production with the cosmic IR background, extremely small intergalactic magnetic fields (\lessim 10^{-22} G) are required.Comment: 11 pages, 1 figur

Educational Leadership in Haiti: A Case Study of Innovative and Exemplary Leadership in a Fragile State

In this study, we consider three school leaders in Haiti who provide examples of innovative and exemplary leadership practices in the midst of challenging circumstances. Using a framework of innovative (Moolenaar, Daly, & Sleeger, 2010; Rogers, 2003) and exemplary leadership practices (Kouzes & Posner, 2006), we examine three themes that emerged from interviews with the three participants, observations of their work in the field, and interviews with other educational stakeholders in their communities. We raise considerations for leadership practices that include: The importance of social and professional networks, barriers and opportunities to innovative practice, and collaborations involving community, regional, national, and international partners. The paper provides suggestions for further exploration in examining educational leadership in fragile states such as Haiti

Power Density Spectra of Gamma-Ray Bursts in the Internal Shock Model

We simulate Gamma-Ray Bursts arising from internal shocks in relativistic winds, calculate their power density spectrum (PDS), and identify the factors to which the PDS is most sensitive: the wind ejection features, which determine the wind dynamics and its optical thickness, and the energy release parameters, which give the pulse 50-300 keV radiative efficiency. For certain combinations of ejection features and wind parameters the resulting PDS exhibits the features observed in real bursts. We found that the upper limit on the efficiency of conversion of wind kinetic energy into 50-300 keV photons is $\sim$ 1%. Winds with a modulated Lorentz factor distribution of the ejecta yield PDSs in accord with current observations and have efficiencies closer to $10^{-3}$, while winds with a random, uniform Lorentz factor ejection must be optically thick to the short duration pulses to produce correct PDSs, and have an overall efficiency around $10^{-4}$.Comment: 6 pages, 4 figures, Latex, submitted to The Astrophysical Journal (05/04/99

On The Synchrotron Self-Compton Emission from Relativistic Shocks and Its Implications for Gamma-Ray Burst Afterglows

We consider the effects of inverse Compton scattering of synchrotron photons from relativistic electrons in GRB afterglows. We compute the spectrum of the inverse Compton emission and find that it can dominate the total cooling rate of the afterglow for several months or even years after the initial explosion. We demonstrate that the presence of strong inverse Compton cooling can be deduced from the effect it has on the time-evolution of the cooling break in the synchrotron spectral component, and therefore on the optical and X-ray afterglow lightcurves. We then show how the physical interpretation of the observed characteristics of the synchrotron spectrum must be modified to take into consideration this extra source of cooling, and give a revised prescription for computing physical parameters characterizing the expanding shock wave from the observed quantities. We find that for a given set of observables (synchrotron break frequencies and fluxes) there is either no consistent physical interpretation or two of them. Finally we discuss the prospects of directly detecting the inverse Compton emission with Chandra. We argue that such a detection is possible for GRBs exploding in a reasonably dense (n>1 cm^-3) medium.Comment: 21 pages, ApJ submitte

Constraints on Off-Axis X-Ray Emission from Beamed GRBs

We calculate the prompt x-ray emission as a function of viewing angle for beamed Gamma-Ray Burst (GRB) sources. Prompt x-rays are inevitable due to the less highly blueshifted photons emitted at angles greater than 1/gamma relative to the beam symmetry axis, where gamma is the expansion Lorentz factor. The observed flux depends on the combinations (gamma Delta theta) and (gamma theta_v), where (Delta theta) is the beaming angle and theta_v is the viewing angle. We use the observed source counts of gamma-ray-selected GRBs to predict the minimum detection rate of prompt x-ray bursts as a function of limiting sensitivity. We compare our predictions with the results from the Ariel V catalog of fast x-ray transients, and find that Ariel's sensitivity is not great enough to place significant constraints on gamma and (Delta theta). We estimate that a detector with fluence limit ~10^{-7} erg/cm^2 in the 2-10 keV channel will be necessary to distinguish between geometries. Because the x-ray emission is simultaneous with the GRB emission, our predicted constraints do not involve any model assumptions about the emission physics but simply follow from special-relativistic considerations.Comment: Submitted to Ap

Sum rules for correlation functions of ionic mixtures in arbitrary dimension d≥2d\geq 2

The correlations in classical multi-component ionic mixtures with spatial dimension $d\geq 2$ are studied by using a restricted grand-canonical ensemble and the associated hierarchy equations for the correlation functions. Sum rules for the first few moments of the two-particle correlation function are derived and their dependence on $d$ is established. By varying $d$ continuously near $d=2$ it is shown how the sum rules for the two-dimensional mixture are related to those for mixtures at higher $d$.Comment: 19 page

Konflik Batinparagasajronenovelmendhunganggitane Yes Ismie Suryaatmadjatintingan Psikologi Sastra

Novel Mendhung anggitane Yes Ismie Suryaatmadja yaiku karya sastra kang nyritakake ngenani kahanan bale somah para paragane kang padha - padha tumindak slingkuh. Saka tumindake paraga kang slenca iki njalari tuwuhe konflik batin lan pa ngaribawa psikologis kang dialami dening paragane. Bale wisma kang ora harmonis iki disebabake karana para paragane padha nggugu nafsune lan kekarepane dhewe - dhewe. Iki merga anane tingkatan kapribaden kang diandharke dening Sigmund Freud sing mangaribawan i wilayah pamikire manungsa. Tingkatan kapribaden kasebut kaperang dadi telu ing antarane (1) Id yaiku naluri utawa pepenginan kang tuwuh saka jroning ati, (2) ego yaiku perwujudan saka id, banjur sing nomer (3) sup erego yaiku prinsip kapribaden kang ngan dhut aspek - aspek moral saka kapribaden saengga bisa ngendhalekake samubarang ala lan becik. Lelandhesan panliten kasebut dadi dhasar anane underaning panliten iki yaiku Kpriye struktur kapribadene paraga, kepriye konflik batin paraga sajrone tumindak slin gkuh, kepriye gegambaran wewatekane paraga, lan apa wae pangaribawa kajiwan saka tumindak slingkuh marang sakupenge sajrone novel Mendhung anggitane Yes Ismie Suryaatmadja Adhedhasar underan panliten kasebut, mula ancas saka panliten iki, yaiku : (1) Ngan dharake struktur kapribadene paraga sajrone novel Mendhung anggitane yes Ismie Suryaatmadja. (2) Ngandharake konflik batin paraga sajrone tumindak slingkuh ing novel Mendhung anggitane yes Ismie Suryaatmadja. (3) Ngandharake gegambaran wewatekane paraga s ajrone tumindak slingkuh ing novel Mendhung anggitane yes Ismie Suryaatmadja. (4) Ngandharake pangaribawa kajiwan saka tumindak slingkuh tumrap kahanan ing sakupenge. Panliten iki nggunakake metodhe dheskriptif kuwalitatif, amarga dhata kang ditliti sajron e panliten iki wujude tetembungan lan ukara, banjur ditliti kanthi cara faktual. Panliten iki uga nggunakake teori psikologi kapribaden Sigmund Freud amarga tumindak kang dialami dening paraga nuwuhake konflik - konflik kang gegayutan karo kajiwan sarta masa lah psikis . Dhata kang digunakake sajrone panliten iki yaiku karya sastra awujud novel anggitane Yes Ismie Suryaatmadja kang cacahe ana 104 kaca. Tata cara kang dicakake kanggo ngumpulake dhata ing panliten iki yaiku kanthi metodhe dhokumentasi. Panglumpu ke dhata kanthi cara nulis kedadeyan apa wae kang bisa didadekake bukti wujud konflik batin saka telung paraga kang onjo lan padha sesambungan yaiku Carik Jasmin, Warsinah, lan Rani sajrone novel Mendhung iki. Sarta maneka dhata - dhata ngenani teori kang d adi lelandhesan panliten iki kang kalumpuk saka maneka sumber kang ana. Asil saka panliten mujudake yen crita saka novel Mendhung bisa dadi patuladhan tur kaca benggala tumraping pamaca. Tumindak slenca yaiku slingkuh kang dumadi ing sawijining kulawarga bisa nyebabake tuwuhe maneka konflik kang disandhang mligine konflik batin, sarta saka tumindake kasebut uga nyebabake pangaribawa kajiwan tumrap anak - anake. Tumindak kang ora becik kaya kasebut bisa njalari paraga kang nindakake ngalami owah - owahan proble m kajiwan merga konflik batin kang dialami mangaribawani tumindake ing bebrayan. Novel Mendhung migunani tumrap pamaca minangka sarana panglipur, minangka piwulang, sarta bisa kanggo patuladhan supaya bisa tumindak becik ing bebrayan kasunyatan

An approach for assessing human health vulnerability and public health interventions to adapt to climate change.

Assessments of the potential human health impacts of climate change are needed to inform the development of adaptation strategies, policies, and measures to lessen projected adverse impacts. We developed methods for country-level assessments to help policy makers make evidence-based decisions to increase resilience to current and future climates, and to provide information for national communications to the United Nations Framework Convention on Climate Change. The steps in an assessment should include the following: a) determine the scope of the assessment; b) describe the current distribution and burden of climate-sensitive health determinants and outcomes; c) identify and describe current strategies, policies, and measures designed to reduce the burden of climate-sensitive health determinants and outcomes; d) review the health implications of the potential impacts of climate variability and change in other sectors; e) estimate the future potential health impacts using scenarios of future changes in climate, socioeconomic, and other factors; f) synthesize the results; and g) identify additional adaptation policies and measures to reduce potential negative health impacts. Key issues for ensuring that an assessment is informative, timely, and useful include stakeholder involvement, an adequate management structure, and a communication strategy

Estimates of Genetic and Phenotypic Trends of Growth Traits in Bali Cattle

The aim of this study was to estimate genetic and phenotypic trends for growth traits including birth (BW), weaning (WW) and yearling weight (YW) in Bali cattle. The number of cattle used to determine growth traits of BW, WW, and YW were 235, 215, and 178 heads, respectively. Estimation of breeding value, phenotypic and genetic correlation were calculated by Restricted Maximum Likelihood and General Linier Model (GLM) procedures, respectively. Genetic trends analysis was performed using the regression mean breeding values on birth year. Phenotypic and genetic correlation among BW and WW were 0.10 and 0.08 respectively and 0.90 and 0.70 for WW and YW respectively. The phenotypic trends for traits of birth and weaning weight were constant, whereas yearling weight was fluctuating from 2000 to 2008. Likewise, in the case of genetic trends, the birth and weaning weight were constant from 2000 to 2008 except for WW in 2005, whereas the genetic trends for yearling weight showed a fluctuation of wide range. According to the breeding value estimated for all traits, the best was the sire No. 0565, whose breeding value for BW, WW and YW were +0.07, +2.79, and +10.25 kg, respectively higher than the mean value of the population. The genetic trends showed that there have been a significant and positive genetic improvement in all growth traits and indicate that selection would be effective. Genetic correlation between WW and YW was high (0.70) which indicates that the selection on weaning weight might also increase yearling weight in Bali cattle