816 research outputs found
Origin of gamma-ray emission in the shell of Cassiopeia A
Non-thermal X-ray emission from the shell of Cassiopeia A (Cas A) has been an
interesting subject of study, as it provides information about relativistic
electrons and their acceleration mechanisms in the shocks. Chandra X-ray
observatory revealed the detailed spectral and spatial structure of this SNR in
X-rays. The spectral analysis of Chandra X-ray data of Cas A shows unequal flux
levels for different regions of the shell, which can be attributed to different
magnetic fields in those regions. Additionally, the GeV gamma-ray emission
observed by Large Area Telescope on board Fermi Gamma Ray Space Telescope
showed that the hadronic processes are dominating in Cas A, a clear signature
of acceleration of protons. In this paper we aim to explain the GeV-TeV
gamma-ray data in the context of both leptonic and hadronic scenario. We
modeled the multi-wavelength spectrum of Cas A. We use synchrotron emission
process to explain the observed non-thermal X-ray fluxes from different regions
of the shell. These result in estimation of the model parameters, which are
then used to explain TeV gamma-ray emission spectrum. We also use hadronic
scenario to explain both GeV and TeV fluxes simultaneously. We show that a
leptonic model alone cannot explain the GeV-TeV data. Therefore, we need to
invoke a hadronic model to explain the observed GeV-TeV fluxes. We found that
although pure hadronic model is able to explain the GeV-TeV data, a
lepto-hadronic model provides the best fit to the data.Comment: Accepted in A&
Beyond E11
We study the non-linear realisation of E11 originally proposed by West with
particular emphasis on the issue of linearised gauge invariance. Our analysis
shows even at low levels that the conjectured equations can only be invariant
under local gauge transformations if a certain section condition that has
appeared in a different context in the E11 literature is satisfied. This
section condition also generalises the one known from exceptional field theory.
Even with the section condition, the E11 duality equation for gravity is known
to miss the trace component of the spin connection. We propose an extended
scheme based on an infinite-dimensional Lie superalgebra, called the tensor
hierarchy algebra, that incorporates the section condition and resolves the
above issue. The tensor hierarchy algebra defines a generalised differential
complex, which provides a systematic description of gauge invariance and
Bianchi identities. It furthermore provides an E11 representation for the field
strengths, for which we define a twisted first order self-duality equation
underlying the dynamics.Comment: 97 pages. v2: Minor changes, references added. Published versio
Acute brucella melitensis M16 infection model in mice treated with tumor necrosis factor-alpha inhibitors
Introduction: There is limited data in the literature about brucellosis related to an intracellular pathogen and anti-tumor necrosis factor alpha (anti-TNFα) medication. The aim of this study was to evaluate acute Brucella infections in mice receiving anti-TNFα drug treatment. Methodology: Anti-TNFα drugs were injected in mice on the first and fifth days of the study, after which the mice were infected with B. melitensis M16 strain. Mice were sacrificed on the fourteenth day after infection. Bacterial loads in the liver and spleen were defined, and histopathological changes were evaluated. Results: Neither the liver nor the spleen showed an increased bacterial load in all anti-TNFα drug groups when compared to a non-treated, infected group. The most significant histopathological findings were neutrophil infiltrations in the red pulp of the spleen and apoptotic cells with hepatocellular pleomorphism in the liver. There was no significant difference among the groups in terms of previously reported histopathological findings, such as extramedullary hematopoiesis and granuloma formation. Conclusions: There were no differences in hepatic and splenic bacterial load and granuloma formation, which indicate worsening of the acute Brucella infection in mice; in other words, anti-TNFα treatment did not exacerbate the acute Brucella spp. infection in mice. © 2015 Kutlu et al
Experimental Investigation of Frost Formation in a Finned-Tube Evaporator under Simulated Real Operation Conditions
Finned tube evaporators are used in a wide range of application such as commercial and industrial cold/freezed storage rooms with high traffic loading under frosting conditions. During the literature survey it has been realized that there is not enough experimental and visual data regarding the unit cooler tested with casing and fan integrated as in real operating conditions. As it is known, the usage of fan and evaporator external case and non-optimum distributor design may affect air and refrigerant side distribution, capacity and frost formation along the fins with respect to degree of maldistribution. In this paper, an evaporator with an integrated fan was manufactured and tested at under frosting conditions by only changing air flow rate at ambient balanced type test laboratory in contrast with testing at wind tunnel and more uniform flow distribution. During the test, operation performed according to three different air flow rate separately. The parameters concerning test operation such as the changes of air temperature, air relative humidity, surface temperature, air-side pressure drop and refrigerant side capacity etc. were followed in detail for each air flow rate. At the same time, the digital and thermal images were captured in front of heat exchanger; thus, the frost temperature distributions, blockage ratios and frost thicknesses occurring throughout all surfaces were investigated. In this study the effect of air flow rate on frosting has been investigated. The test and visual results showed that the trendline of air side pressure drop has increased slowly at the first stage of test operations, then this phenomena has increased linearly up to a top point and then the linearity has disrupted instantly and this point has admitted beginning of defrost operation for each case. On the other hand, the refrigerant capacities were declined continuously during the test operations. When examining visual and thermal images captured at certain time intervals, it was shown an uneven frost layers and detected the temperature distributions in front of evaporator as different degree for each case via thermal and digital camera. Similarly, the frost thicknesses distribution with time occurring at the specific area of each circuit was identified via macro lens and Matlab Image Process Program. Moreover, the initial period of frost growth, which have significant impact on further frost growth, was followed and the stages of frost growth has been determined.
Definition of the Ethical Values and Ethics Codes for Turkish Midwifery: A Focused Group Study in Kocaeli
Background: The independent roles of midwives have not been properly defined, and midwifery ethical values and moral codes proper to Turkish culture have not been developed. The absence of legal regulations concerning midwifery has negatively affected midwifery in the process of professionalization.
Objectives: The purpose of this study was to identify the professional values of midwifery in Turkey.
Materials and Methods: A focus group was created with the participation of nine midwives working at two state hospitals and a university hospital that provide birth service for women in Kocaeli, which is the most important industrial city in Turkey. The opinions of the midwives on the characteristics that a good midwife should possess and the professional values that a good midwife should observe were collected via in-depth interviews. The interviews were recorded. A total of three meetings were held with the participants. Finally, the notes taken by the reporter during these interviews were rearranged, and the recordings were transcribed by the researchers.
Results: The characteristics suggested by the participants were classified into three categories: professional, personal, and interpersonal. Professional competence, capacity to properly inform interested parties, trustworthiness, respect for individuals and human dignity, and empathy were the most commonly named characteristics. As for the professional values of midwifery, professional competence, trustworthiness, responsibility, maximum benefit, and protection of privacy were the most often identified. Midwives also reported that most of the difficulties they faced in the exercise of daily tasks concerned protecting the privacy of their patients as well as the integrity and prestige of the profession, achieving the maximum benefit and least harm for patients, and providing a just and equal service.
Conclusions: The professional values were mentioned by participant midwives were similar to the values proposed by international professional organizations. But there were some differences perhaps due to cultural differences
Assessing and managing scenery of the Caribbean Coast of Colombia
This study provides the coastal scenery assessment of 135 sites along the Colombian Caribbean littoral by
analysing 26 physical and human factors. Sites were categorised into five classes from Class 1, top grade
scenery, to Class 5, poor scenery. Fifty five percent of the investigated coastal areas were included in
Classes 1 and 2, 18% belonged to Class 3 and 47% of the sites fall into Classes 4 and 5. Classification of
analysed sites depends on the geological setting and the degree of human occupation. Classes 1 and 2
sites are located in natural protected areas in La Guajira and Magdalena departments. Low classification
recorded at Classes 3, 4 and 5 corresponds to a progressive decrease of both natural and (especially)
human parameters. Concerning coastal management issues, emphasis should be given to the upgrading
of human parameters eliminating litter and sewage evidences, vegetation debris and enhancing beach
nourishment work
Frequency of skeletal chest injuries associated with cardiopulmonary resuscitation: forensic autopsy
BACKGROUND: Fractured ribs and sternum are frequent complications of thoracic compression during CPR (cardiopulmonary resuscitation) in adults. This study was conducted to determine the incidence of rib and sternal fractures after conventional closed-chest compression in the treatment of cardiac arrest. METHODS: We reviewed the forensic autopsy findings of 231 deaths referred to the Pamukkale University Department of Forensic Medicine over a 12-month period, 2004-2005. CPR-related chest injuries comprising rib and sternum fractures, ecchymosis and subcostal hemorrhage were compared retrospectively in 104 patients. RESULTS: Ninety-one (87.5%) of the 104 patients were adults, and 13 patients (12.5%) were children. The mean (SD) age in the pediatric group (5F/8M) was 5.48 (±5.96) and in the adult group (18F/73M) was 44.88 (±18.31). Forty-four (42.3%) of the 104 patients died of traumatic cause and 60 (57.7%) of non-traumatic cause. Ecchymosis was present in 26 (28.8%) patients, subcostal hemorrhage in 16 (17.6%) patients and fractures (sternal and costal) in 12 (13.2%) patients in adults. There were no significant differences between groups according to age, sex and traumatic-nontraumatic cause in terms of skeletal chest injuries associated with CPR in adult patients (p>0.05). CONCLUSION: This study shows a low incidence of rib and sternal fracture after closed-chest compression in the treatment of cardiac arrest in forensic autopsy cases
Assessment of cardiac ultrasonography in predicting outcome in adult cardiac arrest
Objective: A prospective follow-up study to evaluate the ability of cardiac ultrasonography performed by emergency physicians to predict resuscitation outcome in adult cardiac arrest patients. METHODS: Ultrasonographic examination of the subxiphoid cardiac area was made immediately on presentation to the emergency department with pulseless cardiac arrest. Sonographic cardiac activity was defined as any detected motion within the heart including the atria, ventricles or valves. Successful resuscitation was defined as any of: return of spontaneous circulation for ≥ 20 min; return of breathing; palpable pulse; measurable blood pressure. RESULTS: The study enrolled 149 patients over an 18-month period. The presence of sonographic cardiac activity at the beginning of resuscitation was significantly associated with a successful outcome (19/27 [70.4%] versus 55/122 [45.1%] patients without cardiac activity at the beginning of resuscitation). CONCLUSIONS: Ultrasono -graphic detection of cardiac activity may be useful in determining prognosis during cardiac arrest. Further studies are needed to elucidate the predictive value of ultrasonography in cardiac arrest patients. © 2012 Field House Publishing LLP
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