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arXivDissipative Photosphere Models of Gammaray Bursts and Xray Flashes M. J. Rees, P. Meszaros 20041231 We consider dissipative effects occurring in the optically thick inner parts of the relativistic outflows producing gammaray bursts and Xray flashes, emphasizing specially the Comptonization of the thermal radiation flux that is advected from the base of the outflow. Such dissipative effects e.g. from magnetic reconnection, neutron decay or shocks  would boost the energy density of the thermal radiation. The dissipation can lead to pair production, in which case the pairs create an effective photosphere further out than the usual baryonic one. In a slow dissipation scenario, pair creation can be suppressed, and the effects are most important when dissipation occurs below the baryonic photosphere. In both cases an increased photospheric luminosity is obtained. We suggest that the spectral peak in gamma ray bursts is essentially due to the Comptonized thermal component from the photosphere, where the comoving optical depth in the outflow falls to unity. Typical peak photon energies range between those of classical bursts and Xray flashes. The relationship between the observed photon peak energy and the luminosity depends on the details of the dissipation, but under plausible assumptions can resemble the observed correlations.
Subject Source arXiv URL https://arxiv.org/abs/astroph/0412702view Article Title Dissipative Photosphere Models of Gammaray Bursts and Xray FlashesAuthors M. J. Rees; P. MeszarosAbstract We consider dissipative effects occurring in the optically thick inner parts of the relativistic outflows producing gammaray bursts and Xray flashes, emphasizing specially the Comptonization of the thermal radiation flux that is advected from the base of the outflow. Such dissipative effects e.g. from magnetic reconnection, neutron decay or shocks  would boost the energy density of the thermal radiation. The dissipation can lead to pair production, in which case the pairs create an effective photosphere further out than the usual baryonic one. In a slow dissipation scenario, pair creation can be suppressed, and the effects are most important when dissipation occurs below the baryonic photosphere. In both cases an increased photospheric luminosity is obtained. We suggest that the spectral peak in gamma ray bursts is essentially due to the Comptonized thermal component from the photosphere, where the comoving optical depth in the outflow falls to unity. Typical peak photon energies range between those of classical bursts and Xray flashes. The relationship between the observed photon peak energy and the luminosity depends on the details of the dissipation, but under plausible assumptions can resemble the observed correlations.Is Part Of Astrophys.J.628:847852,2005 20041231 Identifier ISSN: DOI 10.1086/430818Category astrophLicense 
arXivNonstandard Consequence Operators Generated By Mixed LogicSystems Robert A. Herrmann 20041231 Mixed logicsystems contain both standard and nonstandard coordinate values. In this paper, it is shown that each of the specifically defined mixed logicsystems generates an internal nonstandard consequence operator.
Subject 수학 Source arXiv URL https://arxiv.org/abs/math/0412562view Article Title Nonstandard Consequence Operators Generated By Mixed LogicSystemsAuthors Robert A. HerrmannAbstract Mixed logicsystems contain both standard and nonstandard coordinate values. In this paper, it is shown that each of the specifically defined mixed logicsystems generates an internal nonstandard consequence operator.Is Part Of 20041231 Identifier ISSN: Category math.LOLicense 
arXivCrack Path Prediction in Anisotropic Brittle Materials Vincent Hakim, Alain Karma 20041231 A force balance condition to predict quasistatic crack paths in anisotropic brittle materials is derived from an analysis of diffuse interface continuum models that describe both shortscale failure inside a microscopic process zone and macroscopic linear elasticity. The derivation exploits the gradient dynamics and translation symmetry properties of this class of models to define a generalized energymomentum tensor whose integral around an arbitrary closed path enclosing the crack tip yields all forces acting on this tip, including Eshelby's configurational forces, cohesive forces, and dissipative forces. This condition is validated quantitatively by numerical simulations.
Subject Source arXiv URL https://arxiv.org/abs/condmat/0412775view Article Title Crack Path Prediction in Anisotropic Brittle MaterialsAuthors Vincent Hakim; Alain KarmaAbstract A force balance condition to predict quasistatic crack paths in anisotropic brittle materials is derived from an analysis of diffuse interface continuum models that describe both shortscale failure inside a microscopic process zone and macroscopic linear elasticity. The derivation exploits the gradient dynamics and translation symmetry properties of this class of models to define a generalized energymomentum tensor whose integral around an arbitrary closed path enclosing the crack tip yields all forces acting on this tip, including Eshelby's configurational forces, cohesive forces, and dissipative forces. This condition is validated quantitatively by numerical simulations.Is Part Of 20041231 Identifier ISSN: DOI 10.1103/PhysRevLett.95.235501Category condmat.mtrlsci condmat.softLicense 
PMC OpenAccessThe September epidemic of asthma exacerbations in children: A search for etiology Neil W. Johnston, Sebastian L. Johnston, Joanne M. Duncan, ... more(9) American Academy of Allergy, Asthma and Immunology. Published by Mosby, Inc. 20041231 Background Predictable peaks of asthma exacerbation requiring hospital treatment, of greatest magnitude in children and of uncertain etiology, occur globally after school returns. Objective We wished to determine whether asthmatic children requiring emergency department treatment for exacerbations after school return in September were more likely to have respiratory viruses present and less likely to have prescriptions for control medications than children with equally severe asthma not requiring emergent treatment. Methods Rates of viral detection and characteristics of asthma management in 57 (of 60) children age 5 to 15 years presenting to emergency departments with asthma in 2 communities in Canada between September 10 and 30, 2001, (cases) were compared with those in 157 agematched volunteer children with asthma of comparable severity studied simultaneously (controls). Results Human picornaviruses were detected in 52% of cases and 29% of controls (P = .002) and viruses of any type in 62% of cases and 41% of controls (P = .011). Cases were less likely to have been prescribed controller medication (inhaled corticosteroid, 49% vs 85%; P < .0001; leukotriene receptor antagonist, 9% vs 21%; P = .04). Conclusion Respiratory viruses were detected in the majority of children presenting to emergency departments with asthma during the September epidemic of the disease and in a significant minority of children with asthma in the community. The latter were more likely to have antiinflammatory medication prescriptions than children requiring emergent treatment. Such medication may reduce the risk of emergency department treatment for asthma during the September epidemic.
Subject 생명과학, 의과학, 인문사회과학 Source PMC OpenAccess URL https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7202457/view Article Title The September epidemic of asthma exacerbations in children: A search for etiologyAuthors Neil W. Johnston; Sebastian L. Johnston; Joanne M. Duncan; Justina M. Greene; Tatiana Kebadze; Paul K. Keith; Madan Roy; Susan Waserman; Malcolm R. SearsAbstract Background Predictable peaks of asthma exacerbation requiring hospital treatment, of greatest magnitude in children and of uncertain etiology, occur globally after school returns. Objective We wished to determine whether asthmatic children requiring emergency department treatment for exacerbations after school return in September were more likely to have respiratory viruses present and less likely to have prescriptions for control medications than children with equally severe asthma not requiring emergent treatment. Methods Rates of viral detection and characteristics of asthma management in 57 (of 60) children age 5 to 15 years presenting to emergency departments with asthma in 2 communities in Canada between September 10 and 30, 2001, (cases) were compared with those in 157 agematched volunteer children with asthma of comparable severity studied simultaneously (controls). Results Human picornaviruses were detected in 52% of cases and 29% of controls (P = .002) and viruses of any type in 62% of cases and 41% of controls (P = .011). Cases were less likely to have been prescribed controller medication (inhaled corticosteroid, 49% vs 85%; P < .0001; leukotriene receptor antagonist, 9% vs 21%; P = .04). Conclusion Respiratory viruses were detected in the majority of children presenting to emergency departments with asthma during the September epidemic of the disease and in a significant minority of children with asthma in the community. The latter were more likely to have antiinflammatory medication prescriptions than children requiring emergent treatment. Such medication may reduce the risk of emergency department treatment for asthma during the September epidemic.Is Part Of The Journal of Allergy and Clinical Immunology 20041231 , Vol.115 (1) , 132138 Identifier ISSN: 10976825, 00916749 DOI 10.1016/j.jaci.2004.09.025Publisher American Academy of Allergy, Asthma and Immunology. Published by Mosby, Inc.Category Asthma; children; viral infections; rhinovirus; school return; inhaled corticosteroid; leukotriene receptor antagonistLicense Since January 2020 Elsevier has created a COVID19 resource centre with free information in English and Mandarin on the novel coronavirus COVID19. The COVID19 resource centre is hosted on Elsevier Connect, the company's public news and information website. Elsevier hereby grants permission to make all its COVID19related research that is available on the COVID19 resource centre  including this research content  immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research reuse and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID19 resource centre remains active. 
arXivSearch for radiative pumping lines of OH masers: I. The 34.6um absorption line towards 1612 MHz OH maser sources J. H. He, R. Szczerba, P. S. Chen, ... more(4) 20041231 The 1612 MHz hydroxyl maser in circumstellar envelopes has long been thought to be pumped by 34.6um photons. Only recently, the Infrared Space Observatory has made possible spectroscopic observations which enable the direct confirmation of this pumping mechanism in a few cases. To look for the presence of this pumping line, we have searched the Infrared Space Observatory Data Archive and found 178 spectra with data around 34.6um for 87 galactic 1612MHz masers. The analysis performed showed that the noise level and the spectral resolution of the spectra are the most important factors affecting the detection of the 34.6um absorption line. Only 5 objects from the sample (3 red supergiants and 2 galactic center sources) are found to show clear 34.6um absorption (all of them already known) while two additional objects only tentatively show this line. The 3 supergiants show similar pump rates and their masers might be purely radiatively pumped. The pump rates of OH masers in late type stars are found to be about 0.05, only 1/5 of the theoretical value of 0.25 derived by Elitzur (1992). We have also found 16 maser sources which, according to the analysis assuming Elitzur's pump rate, should show the 34.6 $\mu$m absorption line but do not. These nondetections can be tentatively explained by farinfrared photon pumping, clumpy nature of the OH masing region or a limbfilling emission effect in the OH shell.
Subject Source arXiv URL https://arxiv.org/abs/astroph/0412707view Article Title Search for radiative pumping lines of OH masers: I. The 34.6um absorption line towards 1612 MHz OH maser sourcesAuthors J. H. He; R. Szczerba; P. S. Chen; A. M. SobolevAbstract The 1612 MHz hydroxyl maser in circumstellar envelopes has long been thought to be pumped by 34.6um photons. Only recently, the Infrared Space Observatory has made possible spectroscopic observations which enable the direct confirmation of this pumping mechanism in a few cases. To look for the presence of this pumping line, we have searched the Infrared Space Observatory Data Archive and found 178 spectra with data around 34.6um for 87 galactic 1612MHz masers. The analysis performed showed that the noise level and the spectral resolution of the spectra are the most important factors affecting the detection of the 34.6um absorption line. Only 5 objects from the sample (3 red supergiants and 2 galactic center sources) are found to show clear 34.6um absorption (all of them already known) while two additional objects only tentatively show this line. The 3 supergiants show similar pump rates and their masers might be purely radiatively pumped. The pump rates of OH masers in late type stars are found to be about 0.05, only 1/5 of the theoretical value of 0.25 derived by Elitzur (1992). We have also found 16 maser sources which, according to the analysis assuming Elitzur's pump rate, should show the 34.6 $\mu$m absorption line but do not. These nondetections can be tentatively explained by farinfrared photon pumping, clumpy nature of the OH masing region or a limbfilling emission effect in the OH shell.Is Part Of Astron.Astrophys. 434 (2005) 201211 20041231 Identifier ISSN: DOI 10.1051/00046361:20040569Category astrophLicense 
arXivThree topological problems about integral functionals on Sobolev spaces Biagio Ricceri 20041231 In this paper, I propose some problems, of topological nature, on the energy functional associated to the Dirichlet problem \Delta u = f(x,u) in Omega, u restricted to the boundary of Omega is 0. Positive answers to these problems would produce innovative multiplicity results on this Dirichlet problem.
Subject 수학 Source arXiv URL https://arxiv.org/abs/math/0412560view Article Title Three topological problems about integral functionals on Sobolev spacesAuthors Biagio RicceriAbstract In this paper, I propose some problems, of topological nature, on the energy functional associated to the Dirichlet problem \Delta u = f(x,u) in Omega, u restricted to the boundary of Omega is 0. Positive answers to these problems would produce innovative multiplicity results on this Dirichlet problem.Is Part Of J. Global Optim. 28 (2004), no. 34, 401404 20041231 Identifier ISSN: DOI 10.1023/B:JOGO.0000026457.77153.5eCategory math.APLicense 
arXivIsospin and symmetry energy effects on nuclear fragment production in liquidgas type phase transition region N. Buyukcizmeci, R. Ogul, A. S. Botvina... more(3) 20041231 We have demonstrated that the isospin of nuclei influences the fragment production during the nuclear liquidgas phase transition. Calculations for Au197, Sn124, La124 and Kr78 at various excitation energies were carried out on the basis of the statistical multifragmentation model (SMM). We analyzed the behavior of the critical exponent tau with the excitation energy and its dependence on the critical temperature. Relative yields of fragments were classified with respect to the mass number of the fragments in the transition region. In this way, we have demonstrated that nuclear multifragmentation exhibits a 'bimodality' behavior. We have also shown that the symmetry energy has a small influence on fragment mass distribution, however, its effect is more pronounced in the isotope distributions of produced fragments.
Subject Source arXiv URL https://arxiv.org/abs/nuclth/0412111view Article Title Isospin and symmetry energy effects on nuclear fragment production in liquidgas type phase transition regionAuthors N. Buyukcizmeci; R. Ogul; A. S. BotvinaAbstract We have demonstrated that the isospin of nuclei influences the fragment production during the nuclear liquidgas phase transition. Calculations for Au197, Sn124, La124 and Kr78 at various excitation energies were carried out on the basis of the statistical multifragmentation model (SMM). We analyzed the behavior of the critical exponent tau with the excitation energy and its dependence on the critical temperature. Relative yields of fragments were classified with respect to the mass number of the fragments in the transition region. In this way, we have demonstrated that nuclear multifragmentation exhibits a 'bimodality' behavior. We have also shown that the symmetry energy has a small influence on fragment mass distribution, however, its effect is more pronounced in the isotope distributions of produced fragments.Is Part Of 20041231 Identifier ISSN: Category nuclth nuclexLicense 
arXivA Survey of Distributed Intrusion Detection Approaches Michael Treaster 20041231 Distributed intrustion detection systems detect attacks on computer systems by analyzing data aggregated from distributed sources. The distributed nature of the data sources allows patterns in the data to be seen that might not be detectable if each of the sources were examined individually. This paper describes the various approaches that have been developed to share and analyze data in such systems, and discusses some issues that must be addressed before fully decentralized distributed intrusion detection systems can be made viable.
Subject Source arXiv URL https://arxiv.org/abs/cs/0501001view Article Title A Survey of Distributed Intrusion Detection ApproachesAuthors Michael TreasterAbstract Distributed intrustion detection systems detect attacks on computer systems by analyzing data aggregated from distributed sources. The distributed nature of the data sources allows patterns in the data to be seen that might not be detectable if each of the sources were examined individually. This paper describes the various approaches that have been developed to share and analyze data in such systems, and discusses some issues that must be addressed before fully decentralized distributed intrusion detection systems can be made viable.Is Part Of 20041231 Identifier ISSN: Category cs.CRLicense 
arXivCovering dimension and nonlinear equations Biagio Ricceri 20041231 Theorem: Let X and Y be two Banach spaces, Phi: X to Y a continuous, linear, surjective operator, and Psi: X to Y a completely continuous operator with bounded range. Then, one has dim{x in X : Phi(x)=Psi(x)} >= dim(Phi^{1}(0)). Here dim denotes the covering dimension.
Subject 수학 Source arXiv URL https://arxiv.org/abs/math/0412563view Article Title Covering dimension and nonlinear equationsAuthors Biagio RicceriAbstract Theorem: Let X and Y be two Banach spaces, Phi: X to Y a continuous, linear, surjective operator, and Psi: X to Y a completely continuous operator with bounded range. Then, one has dim{x in X : Phi(x)=Psi(x)} >= dim(Phi^{1}(0)). Here dim denotes the covering dimension.Is Part Of RIMS Kokyuroku 1031, 97100 (1998) 20041231 Identifier ISSN: Category math.FALicense 
arXivThe KrepsYan theorem for $L^\infty$ Dmitry B. Rokhlin 20041231 We prove the following version of the KrepsYan theorem. For any norm closed convex cone $C\subset L^\infty$ such that $C\cap L_+^\infty=\{0\}$ and $C\supset L_+^\infty$, there exists a strictly positive continuous linear functional, whose restriction on $C$ is nonpositive. The proof uses some tools from convex analysis in contrast to the case of a weakly Lindel\"of Banach space, where such approach is not needed.
Subject 수학 Source arXiv URL https://arxiv.org/abs/math/0412551view Article Title The KrepsYan theorem for $L^\infty$Authors Dmitry B. RokhlinAbstract We prove the following version of the KrepsYan theorem. For any norm closed convex cone $C\subset L^\infty$ such that $C\cap L_+^\infty=\{0\}$ and $C\supset L_+^\infty$, there exists a strictly positive continuous linear functional, whose restriction on $C$ is nonpositive. The proof uses some tools from convex analysis in contrast to the case of a weakly Lindel\"of Banach space, where such approach is not needed.Is Part Of 20041231 Identifier ISSN: Category math.FALicense