65 research outputs found
Entropy bound for a charged object from the Kerr-Newman black hole
We derive again the upper entropy bound for a charged object by employing
thermodynamics of the Kerr-Newman black hole linearised with respect to its
electric chargeComment: latex, 4 pages, no figures. In this version, the desired bound is
well obtained by varying correctly the entropy of the black hol
Black holes in which the electrostatic or scalar equation is solvable in closed form
We show that the method used in the Schwarzschild black hole for finding the
elementary solution of the electrostatic equation in closed form cannot extend
in higher dimensions. By contrast, we prove the existence of static,
spherically symmetric geometries with a non-degenerated horizon in which the
static scalar equation can be solved in closed form. We give the explicit
results in 6 dimensions. We determine moreover the expressions of the
electrostatic potential and of the static scalar field for a point source in
the extremal Reissner-Nordstrom black holes in higher dimensions.Comment: 20 pages, no figur
Electrostatics in a Schwarzschild black hole pierced by a cosmic string
We explicitly determine the expression of the electrostatic potential
generated by a point charge at rest in the Schwarzschild black hole pierced by
a cosmic string. We can then calculate the electrostatic self-energy. From
this, we find again the upper entropy bound for a charged object by employing
thermodynamics of the black hole.Comment: Latex, 8 pages, 1 figure in late
Cosmic Censorship, Area Theorem, and Self-Energy of Particles
The (zeroth-order) energy of a particle in the background of a black hole is
given by Carter's integrals. However, exact calculations of a particle's {\it
self-energy} (first-order corrections) are still beyond our present reach in
many situations. In this paper we use Hawking's area theorem in order to derive
bounds on the self-energy of a particle in the vicinity of a black hole.
Furthermore, we show that self-energy corrections {\it must} be taken into
account in order to guarantee the validity of Penrose cosmic censorship
conjecture.Comment: 11 page
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Healthy Eating Promotion for the Workplace: the European FOOD (Fighting Obesity through Offer and Demand) Programme Promozione di un'alimentazione sana sul posto di lavoro: il programma europeo FOOD (Combattere l'obesità attraverso l'offerta e la domanda)
Diet related chronic diseases are a key public health challenge. As employees spend a significant amount of their waking hours at work, it is an important place to convey health promotion messages and improve the workers’ eating behaviour. The Fighting Obesity through Offer and Demand (FOOD) programme contributes to this objective by promoting healthy eating habits during the working day. There are two complementary target groups: workers and restaurant owners. The FOOD programme is a public private consortium in nine European countries involving representatives of public health authorities, nutritionists and universities around the lead partner and coordinator the private company Edenred. Here we present the results from a 2018 survey with 25,428 employees and 1,411 restaurants supported by 910 semi-structured interviews (260 face to face and 650 telephone interviews).
Key findings include an increase in demand for healthy foods since 2012. There is a tension with the demands for healthy food being accompanied by expectations of a ‘cheap’ and convenient service. The proportion of people taking a mid-day break is approximately 50% across the sample. Lunchtime at work remains an important point for promoting healthy eating among employees. While nutrition is important the promotion of social eating is also important as it introduces other benefits including increased productivity and promotes mental health.
For the future restaurant owners and their employees need more support to deliver healthy eating options and to provide more nudges toward healthy eating
Extended Fermi coordinates
We extend the notion of Fermi coordinates to a generalized definition in
which the highest orders are described by arbitrary functions. From this
definition rises a formalism that naturally gives coordinate transformation
formulae. Some examples are developped in which the extended Fermi coordinates
simplify the metric components.Comment: 16 pages, 1 figur
Cutaneous lesions of the nose
Skin diseases on the nose are seen in a variety of medical disciplines. Dermatologists, otorhinolaryngologists, general practitioners and general plastic and dermatologic surgeons are regularly consulted regarding cutaneous lesions on the nose. This article is the second part of a review series dealing with cutaneous lesions on the head and face, which are frequently seen in daily practice by a dermatologic surgeon. In this review, we focus on those skin diseases on the nose where surgery or laser therapy is considered a possible treatment option or that can be surgically evaluated
Champ vectoriel et configurations d\u27équilibre de grosses masses en relativité générale
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