Clustering of gamma-ray burst types in the Fermi-GBM catalogue: indications of photosphere and synchrotron emissions during the prompt phase

Many different physical processes have been suggested to explain the prompt gamma-ray emission in gamma-ray bursts (GRBs). Although there are examples of both bursts with photospheric and synchrotron emission origins, these distinct spectral appearances have not been generalized to large samples of GRBs. Here, we search for signatures of the different emission mechanisms in the full Fermi Gamma-ray Space Telescope GBM catalogue. We use Gaussian Mixture Models to cluster bursts according to their parameters from the Band function ($\alpha$, $\beta$, and $E_{pk}$) as well as their fluence and $T_{90}$. We find five distinct clusters. We further argue that these clusters can be divided into bursts of photospheric origin (2/3 of all bursts, divided into 3 clusters) and bursts of synchrotron origin (1/3 of all bursts, divided into 2 clusters). For instance, the cluster that contains predominantly short bursts is consistent of photospheric emission origin. We discuss several reasons that can determine which cluster a burst belongs to: jet dissipation pattern and/or the jet content, or viewing angle.Comment: Accepted for publication in MNRA

Emission from accelerating jets in gamma-ray bursts: Radiation dominated flows with increasing mass outflow rates

We study the narrowest spectra expected from gamma-ray bursts. We present an analytical function for the spectrum that is emitted from the photosphere of a radiation-dominated flow that is under acceleration. This is the narrowest possible spectrum and it differs from a Planck function. We also present numerical spectra from photospheres occurring during the transition into the coasting phase of the flow. Using these spectral models, we reanalyse Fermi observations of GRB100507 and GRB101219, which both have been reported to have very narrow spectra. The bursts can be fitted by the spectral models: For GRB101219 the spectrum is consistent with the photosphere occurring below or close to the saturation radius, while for GRB100507 the photosphere position relative to the saturation radius can be determined as a function of time. In the latter case, we find that the photosphere initially occurs in the acceleration phase and thereafter transitions into the coasting phase. We also find that this transition occurs at the same time as the change in observed cooling behaviour: the temperature is close to constant before the break and decays after. We argue that such a transition can be explained by an increasing mass outflow rate. Both analysed bursts thus give strong evidence that the jets are (initially) radiation dominated.Comment: Accepted by MNRA

AN EFFECTIVE RISK-PREVENTIVE MODEL PROPOSAL FOR OCCUPATIONAL ACCIDENTS AT SHIPYARDS

According to the statistics of occupational accidents, it is observed that the number of accidents occurred in shipbuilding industry is high and the rate of deaths and serious injuries among these accidents is higher than in other industries. However, the number of the studies to prevent these accidents in both industrial and scientific practices is considerably low. Therefore, the objective of this study is to develop an efficient risk preventive model in accordance with occupational health and safety regulations for industrial organizations. The approach proposed in this study differs from those described in the literature, because it is based on fuzzy set theory in order to cope with uncertainties on probability and severity definitions in terms of occupational health and safety. Furthermore, in this paper, risk severity is considered in terms of harm to worker, harm to environment, and harm to hardware, whereas in the literature, risk severity is generally considered solely in terms of only harm to worker. Then, risk magnitude is obtained by utilizing fuzzy inference system. The proposed approach is applied to a shipyard located in the Marmara Region in order to illustrate the applicability of the model

Fragrant grapes on the trail of flavour as part of gastronomy tourism

Anadolu, binlerce yıllık geçmişiyle üzümün anavatanı ve gen merkezi konumundadır. Bu coğrafyada yaşayan her medeniyet üzümü ve üzümden elde ettikleri ürünleri mutfak kültürlerinin içine almışlar ve mutfak kültürlerini farklılaştırmışlardır. Bu farklılık ise her geçen gün turizm açısından daha fazla çekicilik unsuru olarak değerlendirilmektedir. Bu doğrultuda değişen turizm dinamikleri ile gastronomi turistleri lezzetlerin takibini yaparak seyahatlerini planlamaktadırlar. Bu çalışma ile kokulu üzümün, Karadeniz Bölgesi’nin Orta ve Doğu sahil şeridinde yer alan illerdeki yeri ve önemi ayrıca gastronomi turizmine yönelik bir ürün olarak potansiyeli ele alınmıştır. Gastronomi turizmine yönelik ilginin arttığı sonucuna bağlı olarak, alternatif bir gastronomik ürün rotası önermesi açısından çalışma önem arz etmektedir. Çalışmanın teorik alt yapısı planlı davranış teorisine dayandırılmıştır. Çalışmanın evrenini Karadeniz Bölgesi’nin Orta ve Doğu sahil şeridinde yer alan; Samsun, Ordu, Giresun, Trabzon, Rize ve Artvin illeri oluşturmaktadır. Çalışmanın verileri nitel araştırma yöntemlerinden doküman inceleme, gözlem ve görüşme tekniğiyle toplanmıştır. Çalışmanın deseni örnek olaydır. Çalışmada veri analizi planı oluşturulmuş, betimsel analiz yöntemi ile veriler analiz edilmiştir. Çalışma ile elde edilen veriler; kokulu üzümün bölge için değerlendirilmesi gereken bir potansiyele sahip olduğu sonucunu ortaya koymaktadır. Dolayısıyla kokulu üzüme yönelik gastronomi rotalarının oluşturulması ile destinasyon çekiciliği arttırılarak destinasyon imajının gelişmesine böylece yerel halkın yaşam kalitesinin yükseltilmesine önemli katkılar sağlanabilecektirAnatolia, with its thousands of years of history, is the homeland and gene center of grapes. Every civilization living in this geography has included grapes and products produced from them into their culinary cultures and differentiated their culinary cultures. This difference is considered more and more attractive in terms of tourism day by day. With the changing tourism dynamics, gastronomy tourists plan their travels by following flavors. In this study, the place and importance of fox grape in the provinces located on the Middle and Eastern coastline of the Black Sea region, and its potential as a product for gastronomy tourism were discussed. Depending on the result that the interest in gastronomic tourism has increased, the study is important in terms of proposing an alternative route of gastronomic product. The theoretical background of the study is based on the theory of planned behavior. The population of the study consists of Samsun, Ordu, Giresun, Trabzon, Rize and Artvin provinces located in the Middle and Eastern coastline of the Black Sea region. Data of the study were collected by document analysis, observation and interview techniques, which are among the qualitative research methods. The research was designed as a case study. In the study, a data analysis plan was created and the data were analyzed using the descriptive analysis method. The data obtained from the study reveal that fox grape has a potential that should be evaluated for the region. Therefore, the creation of gastronomic routes to fox grape can contribute to increasing the attractiveness of the destination and improving the image of the destination, and thus to increasing the local people’s quality of life

The Fraction of Gamma-ray Bursts with an Observed Photospheric Emission Episode

There is no complete description of the emission physics during the prompt phase in gamma-ray bursts. Spectral analyses, however, indicate that many spectra are narrower than what is expected for non-thermal emission models. Here, we reanalyse the sample of 37 bursts in \citet{Yu2019}, by fitting the narrowest time-resolved spectrum in each burst. We perform model comparison between a photospheric and a synchrotron emission model based on Bayesian evidence. We choose to compare the shape of the narrowest expected spectra: emission from the photosphere in a non-dissipative flow and slow-cooled synchrotron emission from a narrow electron distribution. We find that the photospheric spectral shape is preferred by $54 \pm 8 \%$ of the spectra (20/37), while $38 \pm 8 \%$ of the spectra (14/37) prefer the synchrotron spectral shape; three spectra are inconclusive. We hence conclude that GRB spectra are indeed very narrow and that more than half of the bursts have a photospheric emission episode. We also find that a third of all analysed spectra, not only prefer, but are also compatible with a non-dissipative photosphere, confirming previous similar findings. Furthermore, we notice that the spectra, that prefer the photospheric model, all have a low-energy power-law indices $\alpha > -0.5$. This means that $\alpha$ is a good estimator of which model is preferred by the data. Finally, we argue that the spectra which statistically prefer the synchrotron model, could equally well be caused by subphotospheric dissipation. If that is the case, photospheric emission during the early, prompt phase would be even more dominant.Comment: Accepted: Ap

Regulatory role of optimism ın the relationship between crisis management applications and business performance of tourism enterprises during the Covid-19 pandemic: an example of TR90 region

Bu çalışmada COVID-19 küresel salgını ile turizm endüstrisi ilişkilendirilmiştir. Bunun önemli nedenleri arasında; salgının sebep olduğu seyahat kısıtlamaları ve turizm sektöründe bazı işletmelerin faaliyetlerine ara vermeleri hatta işletmelerin salgın şartlarında uymak zorunda oldukları düzenlemelerdir. Dolayısıyla çalışma kapsamında bu nedenlerle ortaya çıkacak muhtemel krizler ve bu krizlerin yönetimi ele alınmıştır. Çalışmanın amacı, COVID-19 küresel salgınla mücadelede turizm sektöründeki yöneticilerin benimsediği kriz yönetim uygulamaları ve işletmelerin performansı arasındaki ilişkide iyimserliğin düzenleyici rolünün olup olmadığının tespit edilmesidir. Çalışmanın modeli, olumlu yönelim teorisi ve kaynakların korunması teorisine dayandırılmıştır. Çalışmada nicel araştırma yaklaşımı benimsenmiştir. Çalışmada, genel tarama araştırmasının bir türü olan ilişkisel tarama yöntemi kullanılmıştır. Çalışmanın evrenini, TR90 Bölgesinde faaliyet gösteren konaklama işletmeleri, seyahat işletmeleri ve yiyecek-içecek işletmelerindeki çalışan personeli kapsamaktadır. Çalışmanın verileri anket tekniği ile toplanmıştır. Çalışmadan elde edilen veriler doğrultusunda, konaklama işletmeleri, seyahat işletmeleri ve yiyecek-içecek işletmelerinde; kriz yönetim uygulamaları ile işletme performansları arasındaki ilişkide iyimserliğin düzenleyici rolünün olduğu sonucuna ulaşılmıştır.the pandemic and the suspension of activities of some businesses in the tourism sector and even the regulations that businesses have to comply with in the pandemic conditions are among the important reasons for this. Therefore, within the scope of the study, possible crises that may arise due to these reasons and the management of these crises are discussed. The aim of the study is to determine whether optimism has a regulatory role in the relationship between the crisis management practices adopted by the managers in the tourism sector and the performance of the enterprises in the fight against the COVID-19 pandemic. The model of the study was based on the theory of positive orientation and conservation of resources theory. Quantitative research approach was adopted in the study. Relational survey method, which is a type of general survey research, was used in the study. The population of the study consisted of accommodation businesses, travel businesses and food and beverage businesses operating in the TR90 Region. The data of the study were collected by questionnaire technique. In line with the data obtained from the study, it was concluded that optimism has a moderating role in the relationship between crisis management practices and business performances in accommodation businesses, travel businesses and food and beverage businesses

The effect of the X, Y, Z generations’ women perspectives on travel intention of female tourists traveling alone: An example of TR90 region

Turizm kaynaklarına erişimde ve turistik seyahatlerde kadınlar ve erkekler eşit hak ve özgürlüklere sahip olmasına rağmen Türkiye‟de ve dünya genelinde hâkim olan bir eşitsizlik anlayışının söz konusu olduğu söylenebilir. Bu çalışmada, tek başına seyahat eden kadın turistler ile ilgili algının, tek başına seyahat etme niyeti üzerinde etkisinin olup olmadığı ve tek başına seyahat etme algısı ve tek başına seyahat etme niyetinin kuşaklara göre bir farklılık gösterip göstermediği incelenmiştir. Ulusal literatür incelendiğinde, kadınların tek başına seyahat algıları ile tek başına seyahat etme niyeti arasındaki ilişkiye yönelik sınırlı sayıda çalışmaya ulaşılmıştır. Bu nedenle bu çalışmanın literatüre katkı sağlayacağı düşünülmektedir. Çalışmanın teorik alt yapısı planlı davranış teorisi, liberal feminizm teorisi ve sosyal etki teorisine dayanmaktadır. Çalışmanın evrenini, TR90 Doğu Karadeniz Bölgesindeki (Artvin, Giresun, Gümüşhane, Ordu, Rize, Trabzon) kadın nüfusu oluşturmaktadır. Veriler anket yolu ile toplanmıştır. Çalışmanın yöntemi, tarama modelleri içerisinde yer alan ilişkisel tarama modelidir. Çalışma bulgularını analiz edebilmek için ANOVA Testi, korelasyon analizi, basit doğrusal regresyon analizi ve hiyerarşik (sıralı) regresyon analizi kullanılmıştır. Çalışmadan elde edilen veriler doğrultusunda, kadınların tek başına seyahate çıkma algısının tek başına seyahat etme niyeti üzerinde etkili olduğu ve tek başına seyahat algısı ile tek başına seyahat etme niyetinin kuşaklara göre farklılık göstermediği sonuçlarına ulaşılmıştır.Although women and men have equal rights and freedoms in accessing tourism resources and in touristic travels, it can be said that there is an understanding of inequality prevailing in Turkey and throughout the world. In this study, it was examined whether the perception of female tourists traveling alone has an effect on the intention to travel alone, and whether the perception of female tourists traveling alone and intention to travel alone differ by generation. When the national literature is examined, a limited number of studies have been found on the relationship between the perception of female tourists traveling alone and their intention to travel alone. Therefore, it is thought that this study will contribute to the literature. The theoretical background of the study is based on planned behavior theory, liberal feminism theory and social impact theory. The population of the study consists of the female population in the TR90 Eastern Black Sea region (Artvin, Giresun, Gümüşhane, Ordu, Rize, Trabzon). The data were collected by using a questionnaire. The method of the study is the relational screening model, which is included in the screening models. ANOVA Test, correlation analysis, simple linear regression analysis and hierarchical (ordinal) regression analysis were used to analyze the study findings. In line with the data obtained from the study, it was concluded that women's perception of traveling alone has an effect on travel intention and that travel perception and travel intention do not differ according to generations

A review on household energy consumption behavior: how about migrated consumers?

This paper reviews the literature on energy consumption behavior for both domestic and migrated/displaced population and aims to recommend crucial policy measures for creating awareness on the energy efficiency. Consumers’ adoption to the efficient usage of energy varies depending on demographic, behavioral and situational dynamics in their households and societies. The regional or national strategies to implement efficient technologies for the consumer engagement are crucial to change their behaviors. Migrants affect the energy usage patterns in the host country due to their different usage behaviors. Any type of measures for migrated population should include available, acceptable, accessible and affordable energy efficiency applications to engage them with the domestic population