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Search Results: 1 - 10 of 401280 matches for " M. Nadalini "
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Comment on "On the tunneling through the black hole horizon" [arXiv:0910.3934]
S. A. Hayward,R. Di Criscienzo,M. Nadalini,L. Vanzo,S. Zerbini
Physics , 2009,
Abstract: The arguments of the above article [arXiv:0910.3934] do not apply to the papers which it criticizes, and contain several key errors, including a fundamental misunderstanding about the equivalence principle.
Local Hawking temperature for dynamical black holes
S. A. Hayward,R. Di Criscienzo,M. Nadalini,L. Vanzo,S. Zerbini
Physics , 2008,
Abstract: A local Hawking temperature is derived for any future outer trapping horizon in spherical symmetry, using a Hamilton-Jacobi variant of the Parikh-Wilczek tunneling method. It is given by a dynamical surface gravity as defined geometrically. The operational meaning of the temperature is that Kodama observers just outside the horizon measure an invariantly redshifted temperature, diverging at the horizon itself. In static, asymptotically flat cases, the Hawking temperature as usually defined by the Killing vector agrees in standard cases, but generally differs by a relative redshift factor between the horizon and infinity, being the temperature measured by static observers at infinity. Likewise, the geometrical surface gravity reduces to the Newtonian surface gravity in the Newtonian limit, while the Killing definition instead reflects measurements at infinity. This may resolve a longstanding puzzle concerning the Hawking temperature for the extremal limit of the charged stringy black hole, namely that it is the local temperature which vanishes. In general, this confirms the quasi-stationary picture of black-hole evaporation in early stages. However, the geometrical surface gravity is generally not the surface gravity of a static black hole with the same parameters.
Local temperature for dynamical black holes
Sean A. Hayward,R. Di Criscienzo,M. Nadalini,L. Vanzo,S. Zerbini
Physics , 2008, DOI: 10.1063/1.3141237
Abstract: A local Hawking temperature was recently derived for any future outer trapping horizon in spherical symmetry, using a Hamilton-Jacobi tunneling method, and is given by a dynamical surface gravity as defined geometrically. Descriptions are given of the operational meaning of the temperature, in terms of what observers measure, and its relation to the usual Hawking temperature for static black holes. Implications for the final fate of an evaporating black hole are discussed.
Reply to Comments on "Invariance of the tunneling method for dynamical black holes" arXiv:0907.2020
S. A. Hayward,R. Di Criscienzo,M. Nadalini,L. Vanzo,S. Zerbini
Physics , 2009,
Abstract: We point out basic misunderstandings about quantum field theory, general relativity and partial derivatives in the above Comments. In reply to a second comment on our first reply by the same author, we also identify precisely where the author's original calculation goes wrong and correct it, yielding the same local Hawking temperature as obtained by the Hamilton-Jacobi method.
Explaining agro-industrial contract breaches: the case of Brazilian tomatoes processing industry
Zylbersztajn, Decio;Nadalini, Lygia B.;
Revista de Economia e Sociologia Rural , 2007, DOI: 10.1590/S0103-20032007000400005
Abstract: three hundred small tomato growers located in brazilian northeast states, supplied a processing industry. in view of the large number of contract hazards and weak enforcement of clauses, managers have decided to move to the midwest, where a reduced number of larger farmers have been contracted. the industry blamed high transaction costs due to the weak mechanism of public enforcement of property rights. the industry blamed some farmers of selling the product at the market for fresh consumption. also, farmers blamed the industry for taking advantage of asymmetric information related to quality. this study presents an analysis of contract architecture and an evaluation of effects of transaction costs related variables on the likelihood of contract breaches. a panel data study with 1,523 observations and limited dependent variable models has been formulated to test hypothesis based on transaction cost theory. results show that opportunism and the absence of courts guarantees of property rights precluded the possibility of achieving a stable contract relationship in the region.
Criminal career-related factors among female robbers in the state of S?o Paulo, Brazil, and a presumed 'revolving-door' situation
Mauá, Fernando Henrique Nadalini;Baltieri, Danilo Antonio;
Revista Brasileira de Psiquiatria , 2012, DOI: 10.1590/S1516-44462012000200010
Abstract: introduction: risk-taking behaviors, family criminality, poverty, and poor parenting have been frequently associated with an earlier onset of criminal activities and a longer criminal career among male convicts. objective: this study aims to identify factors related to the onset and recurrence of criminal behavior among female robbers in the state of s?o paulo - brazil. method: it was a cross-sectional study carried out inside a feminine penitentiary in s?o paulo. from june 2006 to june 2010, 175 inmates convicted only for robbery were recruited to be evaluated about family antecedents of criminal conviction, alcohol and drug misuse, impulsiveness, depressive symptoms, and psychosocial features. results having family antecedents of criminal conviction consistently predicted an earlier onset of criminal activities and a longer criminal career among female robbers. drug use in youth and the severity of drug misuse were significantly related to the initiation and recurrence of criminal behavior, respectively. discussion: prisons must systematically screen detainees and provide treatments for those with health problems in general. children of inmates should obtain help to modify the negative consequences of their parents' incarceration in order to mitigate the negative consequences of pursuing this 'static' factor.
Human Sperm Cryopreservation: Update on Techniques, Effect on DNA Integrity, and Implications for ART
Marlea Di Santo,Nicoletta Tarozzi,Marco Nadalini,Andrea Borini
Advances in Urology , 2012, DOI: 10.1155/2012/854837
Abstract: Cryopreservation of human spermatozoa—introduced in the 1960's—has been recognized as an efficient procedure for management of male fertility before therapy for malignant diseases, vasectomy or surgical infertility treatments, to store donor and partner spermatozoa before assisted reproduction treatments and to ensure the recovery of a small number of spermatozoa in severe male factor infertility. Despite the usefulness of it, cryopreservation may lead to deleterious changes of sperm structure and function: while the effects of cryopreservation on cells are well documented, to date there is no agreement in the literature on whether or not cryopreservation affects sperm chromatin integrity or on the use of a unique and functional protocol for the freezing-thawing procedure. Therefore, sperm cryopreservation is an important component of fertility management and much of its successful application seems to affect the reproductive outcome of assisted reproduction technologies (ART): appropriate use of cryoprotectants before and sperm selection technologies after cryopreservation seem to have the greatest impact on preventing DNA fragmentation, thus improving sperm cryosurvival rates. 1. Introduction The procedure that makes it possible to stabilize the cells at cryogenic temperatures is called cryopreservation, also known as an applied aspect of cryobiology or the study of life at low temperatures. Many advances in the cryopreservation technology have led to the development of methods that allow for low-temperature maintenance of a variety of cell types including male and female gametes, small multicellular organisms, and even more complex organisms such as embryos. Cryopreservation of human spermatozoa—introduced in the 1960’s [1]—has overcome many space and time limitations and now forms integral part of assisted reproduction technologies (ARTs). This technique becomes particularly important in cases of preservation of male fertility before radiotherapy or chemotherapy [2] which may lead to testicular failure or ejaculatory dysfunction. In fact, semen cryostorage seems to be the only proven method that may offer these couples a chance of having children in the future: cancer therapy could in fact lead to damage, resulting in subfertility or sterility due to gonad removal or permanent damage to germ cells caused by adjuvant therapy. In particular, the risk associated to therapy depends on several factors: the age of the patient at the time of treatment, the dose, site, and type of treatment [3]. Also some nonmalignant diseases, such as diabetes and
INTRAOCULAR TRANSMISSIBLE VENEREAL TUMOR IN A DOG
Rodrigues, Geórgia Nadalini;Alessi, Antonio Carlos;Laus, José Luiz;
Ciência Rural , 2001, DOI: 10.1590/S0103-84782001000100023
Abstract: canine transmissible venereal tumor (tvt) is a round cell neoplasm occurring on the external genital mucosa of male and female dogs. transmission is by cell implantation during coitus, licking, or other interaction between an affected dog and a susceptible host. metastasis of the tumor rarely occurs. this report describes an unusual presentation of tvt with intraocular involvement and inguinal lymph nodes metastasis. the subject was a six-year-old, intact, male, brazilian terrier dog with a history of abnormal masses in the right eye, penis and several subcutaneous nodules in the inguinal area. histopathological examination of the eye specimens as well as cytologic examination of penile mass and subcutaneous nodules revealed similar findings. the examination revealed round cells containing a large nuclei with prominent, central located nucleoli and a pale cytoplasm containing few small, clear round vacuoles. histologically, the subcutaneous nodules in the inguinal area were lymph nodes. the diagnosis of tvt with intraocular involvement and lymph nodes metastasis was based on clinical, cytologic and histopathologic findings.
Hamilton-Jacobi Tunneling Method for Dynamical Horizons in Different Coordinate Gauges
Roberto Di Criscienzo,Sean A. Hayward,Mario Nadalini,Luciano Vanzo,Sergio Zerbini
Physics , 2009, DOI: 10.1088/0264-9381/27/1/015006
Abstract: Previous work on dynamical black hole instability is further elucidated within the Hamilton-Jacobi method for horizon tunneling and the reconstruction of the classical action by means of the null-expansion method. Everything is based on two natural requirements, namely that the tunneling rate is an observable and therefore it must be based on invariantly defined quantities, and that coordinate systems which do not cover the horizon should not be admitted. These simple observations can help to clarify some ambiguities, like the doubling of the temperature occurring in the static case when using singular coordinates, and the role, if any, of the temporal contribution of the action to the emission rate. The formalism is also applied to FRW cosmological models, where it is observed that it predicts the positivity of the temperature naturally, without further assumptions on the sign of the energy.
Study of Duct Characteristics Deduced from Low Latitude Ground Observations of Day-Time Whistler at Jammu  [PDF]
M. Altaf, M. M. Ahmad
International Journal of Astronomy and Astrophysics (IJAA) , 2013, DOI: 10.4236/ijaa.2013.33032
Abstract:

Propagation characteristics of low latitude whistler duct characteristics have been investigated based on day-time measurements at Jammu. The morphogical characteristics of low latitude whistlers are discussed and compared with characteristics of middle and high latitude whistlers. The Max. electron density (Nm) at the height of the ionosphere obtained from whistler dispersion comes out to be higher than that of the background which is in accordance with the characteristics of whistler duct. The equivalent width is found to be close to the satellite observations and the characteristics of whistler duct in low latitude ionosphere are similar to those in middle and high latitude ionosphere. The width of ducts estimated from the diffuseness of the whistler track observed during magnetic storm is found to lie in the range of 50 - 200 Km.

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