We extend the results of Yu et al. (2015b) of the novel sharpness angle measurement to a large number of spectra obtained from the Fermi gamma-ray burst monitor. The sharpness angle is compared to the values obtained from various representative emission models: blackbody, single-electron synchrotron, synchrotron emission from a Maxwellian or power-law electron distribution. It is found that more than 91% of the high temporally and spectrally resolved spectra are inconsistent with any kind of optically thin synchrotron emission model alone. It is also found that the limiting case, a single temperature Maxwellian synchrotron function, can only contribute up to 58+23 -18% of the peak flux. These results show that even the sharpest but non-realistic case, the single-electron synchrotron function, cannot explain a large fraction of the observed spectra. Since any combination of physically possible synchrotron spectra added together will always further broaden the spectrum, emission mechanisms other than optically thin synchrotron radiation are likely required in a full explanation of the spectral peaks or breaks of the GRB prompt emission phase.

A redback system is a binary system composed of a pulsar and a main sequence star. The inverse Compton (IC) scattering between the stellar soft photons and the relativistic pulsar wind will generate orbital-modulating GeV photons. We look for these IC emissions from redback systems. A multi-wavelength observation of an unassociated gamma-ray source, 3FGL J2039.6-5618, by Salvetti et al. (2015) detected an orbital modulation with a period of 0.2 days in both X-ray and optical cases. They suggested 3FGL J2039.6-5618 to be a new redback candidate. We analyzed the gamma-ray emission of 3FGL J2039.6-5618 using the data from the Fermi large area telescope (Fermi-LAT) and obtained the spectrum in different orbital phases. We propose that the spectrum has orbital dependency and estimate the characteristic energy of the IC emission from the stellar-pulsar wind interaction.

It is generally believed that the high energy emissions from isolated pulsars are emitted from relativistic electrons/positrons accelerated in outer magnetospheric accelerators (outergaps) via a curvature radiation mechanism, which has a simple exponential cut-off spectrum. However, many gamma-ray pulsars detected by the Fermi LAT (Large Area Telescope) cannot be fitted by simple exponential cut-off spectrum, and instead a sub-exponential is more appropriate. It is proposed that the realistic outergaps are non-stationary, and that the observed spectrum is a superposition of different stationary states that are controlled by the currents injected from the inner and outer boundaries. The Vela and Geminga pulsars have the largest fluxes among all targets observed, which allows us to carry out very detailed phase-resolved spectral analysis. We have divided the Vela and Geminga pulsars into 19 (the off pulse of Vela was not included) and 33 phase bins, respectively. We find that most phase resolved spectra still cannot be fitted by a simple exponential spectrum: in fact, a sub-exponential spectrum is necessary. We conclude that non-stationary states exist even down to the very fine phase bins.

We use the non-stationary three dimensional two-layer outer gap model to explain gamma-ray emissions from a pulsar magnetosphere. We found out that for some pulsars like the Geminga pulsar, it was hard to explain emissions above a level of around 1 GeV. We then developed the model into a non-stationary model. In this model we assigned a power-law distribution to one or more of the spectral parameters proposed in the previous model and calculated the weighted phaseaveraged spectrum. Though this model is suitable for some pulsars, it still cannot explain the high energy emission of the Geminga pulsar. An Inverse-Compton Scattering component between the primary particles and the radio photons in the outer magnetosphere was introduced into the model, and this component produced a sufficient number of GeV photons in the spectrum of the Geminga pulsar.

This study examined radiation damage and the optimal gamma-ray dose for mutation breeding in oat (Avena sativa L. cv. Samhan). The seed germination rate decreased as the dose increased over 500 Gy. The median lethal dose (LD50) was approximately 392 Gy. The median reduction dose (RD50) for plant height, tiller number, root length, and flash weight was 411, 403, 394, and 411 Gy, respectively. The optimal dose of gamma irradiation for inducing oat mutation appears to be in the range 300-400 Gy. We performed the comet assay to observe nuclear DNA damage induced by gamma-ray irradiation. This assay showed a clear difference with gamma-ray treatments. DNA damage increased temporarily 7 days after treatment depending on the dose, while no significant difference was identified in response to 300 Gy 30 days after the gamma-ray treatments. The growth characteristics of the M2 generation decreased as the dose increased over 400 Gy.

Rose (Rosa Hybrida Hort.) are of a high symbolic value and a great cultural importance in different societies. They are widely used as garden ornamental plants and as cut flowers. For the induction of mutation, gamma-rays are widely used as a mutagen. This study was carried out to establish a system for mutation breeding by irradiation of gamma-ray in rose. The rooted cuttings of five cultivar roses (Lovelydia, Vital, Aqua, Yellowbabe and Haetsal) are grown by in a greenhouse. They were two difference treatment (Before rooting gamma-ray irradiation, After rooting gamma-ray irradiation) were exposed to dose of 70 Gy using a 60Co gamma-irradiator (150 TBq of capacity ; ACEL, Canada) at the Korea Atomic Energy Research Institute. The irradiated plants were planted in a greenhouse, and investigated survival rate, mutation rate, flower buds number, and shoot length were planted after 80days. The two treatments of and growth characters was significantly reduced to 20% to 40% compared with the control. In addition, survival rate and mutation rate were ‘after rooting γ-ray irradiation (37.4~67.3% and 0.5~5.6%)’ higher than ‘before rooting γ-ray irradiation (18.3~50.8% and 0.3~3.4%)’. Mutation types were solid type, chimeric and mosaic petal mutants with various colors were induced from five rose. These results indicate that efficiency of mutation induction in rose by gamma-ray irradiation on petal colors and petal shapes in two difference treatment with rooted cutting system.

양성자핵반응에 대한 연구는 현재 핵융합로의 재료 개발을 비롯하여 양성자치료 분야 등을 중심으로 활발하게 이루어지고 있다. 본 연구는 100 MeV 양성자 빔을 이용한 27Al(p,3p+n)24Na 반응을 통하여 발생되는 지발 감마선(2754, 1386 keV) 스펙트럼을 고순도 HPGe 검출기를 이용하여 측정하였다. 실험에 사용되어진 양성자 빔은 양성자가속기연구센터(KOMAC)에 설치되어 있는 100 MeV 양성자선형가속기를 사용하였다. 측정된 감마선은 기존에 알려진 결과들과 비교분석하였다. 측정된 감마선의 강도는 고에너지 감마선 검출효율을 결정하는데 매우 중요한 정도를 제공 할 것으로 생각되어 진다.

Odyssey, one of the NASA’s Mars exploration program and SELENE (Kaguya), a Japanese lunar orbiting spacecraft have a payload of Gamma-Ray Spectrometer (GRS) for analyzing radioactive chemical elements of the atmosphere and the surface. In these days, gamma-ray spectroscopy with a High-Purity Germanium (HPGe) detector has been widely used for the activity measurements of natural radionuclides contained in the soil of the Earth. The energy spectra obtained by the HPGe detectors have been generally analyzed by means of the Window Analysis (WA) method. In this method, activity concentrations are determined by using the net counts of energy window around individual peaks. Meanwhile, an alternative method, the so-called Full Spectrum Analysis (FSA) method uses count numbers not only from full-absorption peaks but from the contributions of Compton scattering due to gamma-rays. Consequently, while it takes a substantial time to obtain a statistically significant result in the WA method, the FSA method requires a much shorter time to reach the same level of the statistical significance. This study shows the validation results of FSA method. We have compared the concentration of radioactivity of 40K, 232Th and 238U in the soil measured by the WA method and the FSA method, respectively. The gamma-ray spectrum of reference materials (RGU and RGTh, KCl) and soil samples were measured by the 120% HPGe detector with cosmic muon veto detector. According to the comparison result of activity concentrations between the FSA and the WA, we could conclude that FSA method is validated against the WA method. This study implies that the FSA method can be used in a harsh measurement environment, such as the gamma-ray measurement in the Moon, in which the level of statistical significance is usually required in a much shorter data acquisition time than the WA method.

This study was conducted to determine the optimal dose of gamma-ray for mutation breeding in sorghum (Sorghum bicolor M.). Gamma-rays irradiated to dry seeds with various doses (0 to 1000 Gy) at Korea Atomic Energy Research Institute. Lethal dosage (LD50) was approximately 256 Gy. Significant decreases in growth characteristics (plant height, tiller number and fresh weight) were observed by dose of increased over 300 Gy. Reduction doses (RD50) was approximately 363 Gy in plant height. We also conducted comet assay to observe nucleus DNA damage due to gamma irradiation. In comet assay, a clear difference was identified over 100 Gy treatments. With increasing doses of gamma-ray in the range of 100 to 400 Gy, the rate of head DNA was decreased significantly from 93.52% to 67.57%. The most of the Sorghum cells were severely damaged in the integrity of DNA by gamma-ray. These data provide valuable information when the optimal dose should be chosen for purpose of mutation breeding program of Sorghum.

we analyzed the survival rate through the measurement of germinability of the gamma-ray irradiated buds of 4 Citrus species, C. hybrid ‘Kiomi’, C. hybrid ‘Setoka’, C. hybrid ‘Kanpei’, and C. junos, in greenhouse. To induce mutation, spring buds of Citrus with 0, 10, 20, 40, 60, 80 and 100 Gy of gamma radiation were irradiated and then were vgrafted onto trifoliate orange rootstock. The rootstock number per gamma ray dosage was two hundreds. After after 6 months growth, the shoot germination rate from gamma ray-irradiated buds presented lower viability than those of non-irradiated buds. Higher dossage of irradiation more inhibited bud germination at all experimental groups of citrus. The viability of unirradiated citrus plants was C. junos > ‘Setoka’ > ‘Kiomi’ > ‘Kanpei’. We have determined LD50 of gamma ray-irradiation. This research was supported by the Basic Science Research Program of the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2010-0007627 and 2009-0094059), and by Golden Seed Project, Ministry of Agriculture, Food and Rural Affairs (MAFRA), Ministry of Oceans and Fisheries (MOF), Rural Development Administration (RDA) and Korea Forest Service (KFS), Republic of Korea

본 연구에서는 후춧가루의 위생화를 위해 감마선, 전자선 및 X-선을 조사한 후 이에 따른 미생물학적 및 관능적 품질변화를 평가하였다. 후춧가루에 감마선, 전자선 및 X-선을 2, 4, 6, 8 및 10 kGy로 각각 조사한 후 미생물 변화와 관능품질 변화를 평가한 결과, 미생물의 경우 선종에 관계없이 흡수선량이 증가할수록 미생물 제어 효과가 증가하는 것으로 나타났으며, 선종별 D10값의 경우 2.24-2.75 kGy범위를 보였으며 방사선 선종에 따른 유의차가 없는 것으로 나타났다. 색도의 경우 명도, 적색도 및 황색도 모두 방사선 선종에 따른 변화가 없는 것으로 판단하였다. 관능적 품질 역시 방사선 선종에 관계없이 흡수선량에 따라 품질저하가 발생되는 것으로 나타났다. 이상의 결과를 종합하여 볼 때 방사선 선종에 따른 후춧가루의 품질변화 차이가 없는 것으로 판단하였으며, 이상의 결과는 X-선의 상업적 이용을 위한 기초 연구 자료로 활용될 수 있을 것으로 사료되었다.

국화 6 품종을 대상으로 감마선(35 Gy) 조사에 의해 유기 된 화색변이체를 선발하고, 식물체 재생을 위한 배지내 식물생 장조절제 적정농도를 구명하여 신품종 육성 가능성을 검토하고 자 수행하였다. 고유품종과 다른 꽃잎의 화색변이율은 ‘SP-410’ 이 15.7%로 가장 높았으며, ‘예스스타’가 10.6%, ‘무지개’가 10.3%순 이었다. ‘무지개’는 이중색(황색/적색, Y7D/R40A) 에서 적색(R42B)으로, ‘예스라인’은 자주색(RP74C)에서 진자 주색(RP63B)으로, ‘예스스타’는 황색/적색(Y4A/RP59A) 이 중색에서 적자주색(RP64A)으로, ‘SP-410’은 백색(W155C)에서 황색(Y2C)으로, ‘예스투게더’의 화심색은 백색(W155C)에서 연보라색(P76B)로, ‘예스우리’의 화심색은 연녹색(YG149A)에 서 짙은 녹색(GY1C)으로 화색이 변한 변이체를 선발하였다. 화색변이체 꽃잎의 신초형성을 위한 배지내 식물생장조정제 의 최적조합은 BA 1.0 mg/L와 NAA 0.5 mg/L, BA 2.0 mg/L 와 NAA 0.5 mg/L의 2조합이였으며, 신초형성율은 품종간에 차이가 있어 ‘예스라인’이 91.6%로 가장 높았다. 감마선 조 사에 의한 화색 변이체의 꽃잎배양 유래 재생식물체는 영양 번식으로 유지되었으며, 3년동안 재배한 결과 화색과 꽃잎의 형태적 특성 차이가 없었다.

We report the detection of a quasi-sinusoidally modulated optical flux with a period of 4.6343 hour in the optical and infrared band of the Fermi source 2FGL J2339.7-0531. Comparing the multi-wavelength observations, we suggest that 2FGL J2339.7-0531 is a γ-ray emitting millisecond pulsar (MSP) in a binary system with an optically visible late-type companion accreted by the pulsar, where the MSP is responsible for the γ-ray emission while the optical and infrared emission originate from the heated side of the companion. Based on the optical properties, the companion star is believed to be heated by the pulsar and reaches peak magnitude when the heated side faces the observer. We conclude that 2FGL J2339.7-0531 is a member of a subclass of γ-ray emitting pulsars -the ‘black widows’- recently revealed to be evaporating their companions in the late-stage of recycling as a prominent group of these newly revealed Fermi sources.

In this review paper we explain the following gamma-ray emission features from the millisecond pulsars. (1) Why is the dipolar field of millisecond pulsars so weak but the magnetic pair creation process may still be able to control the size of the outergap? (2) A sub-GeV pulse component could occur in the vicinity of the radio pulse of millisecond pulsars. (3) Orbital modulated gamma-rays should exist in the black widow systems for large viewing angle.

Rice is one of the most important food crops in the world, and has been used as model monocots for genetic studies, because of its relatively small genome size. We have previously reported the different functions of several RING (Really Interesting New Gene) proteins to respond the various abiotic stresses. In order to study a regulation of RING proteins in rice under ionizing irradiation such as gamma ray (GA), we have identified the expression patterns of these genes by RT-PCR. We found Gamma-ray induced RING finger protein (OsGRP) gene, which were associated with cytosol by subcellular localization analysis. in vitro ubiquitination assay revealed that OsGRP possess E3 ligase activity. Also, we demonstrate that C196A point mutation in the RING finger domain of OsGRP can have a critical effect to the breakdown of structural integrity in RING constructs. To identify the interaction partners for OsGRP in protein-protein interactions, we found the seven genes interacted with OsGRP by Yeast Two Hybrid method. To examine the GA-influence of interaction partners by RT-PCR, two genes were specifically down-regulated in rice during GA treatment. These interaction partners were identified the reliable interactions and subcellular localizations via BiFC method. Interestingly, five genes associated with plastid, while two down-regulated genes associated with cytosol and plastid. These results of OsGRP based on genetic approach might provide a clue to understanding the GA responsive mechanism in rice.

Mutant analysis is one of most optimized genome-wide approach towards acquiring utile phenotypes and defining related genes. Gamma-irradiation, an acknowledged way of mutant-generating method, was applied to gain sets of mutant line in Brachypodium distachyon. B. distachyon is a model plant, commonly used in genus of Gramineae for the research of structure genomics and functional genomics. B. distachyon contribute to rapid and easy analysis because of its small size and quick growth. Mutant population was generated by different doses of gamma-irradiation (0, 50, 100, 150, 200, 250 Gy) in the gamma field phytotron. Distance from the source gives same irradiation duration for each plant. Plant growth parameters such as plant height, tiller number, leaf length & width, internode number & diameter, maturity and yield components (ear number biomass) were scored on M0 plants. Plant responses to different doses of radiation are evaluated and the effective radiation dosages to generate mutant using gamma-phytotron are suggested. Chronic irradiation using gamma-phytotron is useful tool to generate mutants for genomic variations such as SNP or INDEL as well as suitable for functional study of genes in Gramineae.

We use the outer gap model to explain the spectrum and the energy dependent light curves of the X-ray and soft γ-rayradiations of the spin-down powered pulsar PSR B1509-58. In the outer gap model, most pairs inside the gap are createdaround the null charge surface and the gap’s electric field separates the opposite charges to move in opposite directions.Consequently, the region from the null charge surface to the light cylinder is dominated by the outflow current and that fromthe null charge surface to the star is dominated by the inflow current. We suggest that the viewing angle of PSR B1509-58 onlyreceives the inflow radiation. The incoming curvature photons are converted to pairs by the strong magnetic field of the star.The X-rays and soft γ-rays of PSR B1509-58 result from the synchrotron radiation of these pairs. The magnetic pair creationrequires a large pitch angle, which makes the pulse profile of the synchrotron radiation distinct from that of the curvatureradiation. We carefully trace the pulse profiles of the synchrotron radiation with different pitch angles. We find that thedifferences between the light curves of different energy bands are due to the different pitch angles of the secondary pairs, andthe second peak appearing at E > 10 MeV comes from the region near the star, where the stronger magnetic field allows thepair creation to happen with a smaller pitch angle.

We revisit the relation between the peak luminosity Liso and the spectral time lag in the source frame. Since gamma-ray bursts (GRBs) are generally thought to be beamed, it is natural to expect that the collimation-corrected peak luminosity may well correlate with the spectral time lag in the source frame if the lag-luminosity relation in the GRB source frame exists. With 12 long GRBs detected by the Swift satellite, whose redshift and spectral lags in the source frame are known, we computed L0,H and L0,W using bulk Lorentz factors Γ0,H and Γ0,W archived in the published literature, where the subscripts H and W represent homogeneous and wind-like circumburst environments, respectively. We have confirmed that the isotropic peak luminosity correlates with the spectral time lag in the source frame. We have also confirmed that there is an anti-correlation between the source-frame spectral lag and the peak energy, Epeak (1 + z) in the source frame. We have found that the collimation-corrected luminosity correlates in a similar way with the spectral lag, except that the correlations are somewhat less tight. The correlation in the wind density profile seems to agree with the isotropic peak luminosity case better than in the homogeneous case. Finally we conclude by briefly discussing its implications.

Kenaf (Hibiscus cannabinus) is an annual herbaceous plant of the family Malvaceae that has been planted in Africa for more than 4000 years and used as source of fiber, energy and feed stock. Also, kenaf seeds are good source for edible oil used for first class cooking oil and margarine production. The seeds can be used for lubrication, soap, paint and varnishes. This study was carried out to evaluate fatty acids variation among sixteen kenaf germplasm and gamma-ray induced mutants derived from Jinju and Auxu. Linoleic, oleic, and palmitic acid were the predominant fatty acids in all kenaf seed oils. The sixteen accessions showed a wide range of fatty acid compositions, spanning from 28.94 to 43.36% saturated, 56.64 to 71.05% total unsaturated, 15.52 to 46.85% monounsaturated, and 13.56 to 48.97% polyunsaturated fatty acids. The mutant lines derived from Jinju, significantly surpassed parental mean for all the palmitic and oleic acid. Also, the mutant lines derived from Auxu showed broad ranges of variation in oleic and linoleic acid and narrow ranges of variation in stearic and palmitic acid. The relative amount of monounsaturated fatty acids (MUFA) were increased at all the gamma-ray induced mutants. These results will provide a valuable information to assist parental selection of kenaf breeding.