In this paper, we give examples that improve the lower bound on the maximum number of halving lines for sets in the plane with 35, 59, 95, and 97 points and, as a consequence, we improve the current best upper bound of the rectilinear crossing number for sets in the plane with 35, 59, 95, and 97 points, provided that a conjecture included in the literature is true. As another consequence, we also improve the lower bound on the maximum number of halving pseudolines for sets in the plane with 35 points. These examples, and the recursive bounds for the maximum number of halving lines for sets with an odd number of points achieved, give a new insight in the study of the rectilinear crossing number problem, one of the most challenging tasks in Discrete Geometry. With respect to this problem, it is conjectured that, for all n multiples of 3, there are 3-symmetric sets of n points for which the rectilinear crossing number is attained.

We report on the orbit of the binary system powering the most extreme ultraluminous X-ray pulsar known to date: NGC 5907 ULX-1 (hereafter ULX1). ULX1 has been the target of a substantial multi-instrument campaign, mainly in the X-ray band, but no clear counterparts are known in other bands. Although ULX1 is highly variable and pulsations can be transient (regardless of the source flux), the timing data collected so far allow us to investigate the orbit of this system. We find an orbital period P-orb = 5.7(-0.6)(+0.1) days and a projected semi-axis A(1) = 3.1(-0.9)(+0.8) lt-s . The most likely ephemeris is P-orb = 5.6585(6) days, A(1) = 3.1(4) lt-s, and the epoch of ascending nodes passage is T-asc = 57751.37(5) MJD. However, there are six similar solutions acceptable within 3 sigma. We find further indications that ULX1 is a high-mass X-ray binary. This implies that we are observing its orbit face on, with an inclination <5(degrees).

In this paper, we improve the lower bound on the minimum number of  ≤k-edges in sets of n points in general position in the plane when k is close to n2. As a consequence, we improve the current best lower bound of the rectilinear crossing number of the complete graph Kn for some values of n.

espanolEn este articulo se esboza un perfil de Newton como hombre y como cientifico. En particular se describen algunas de sus principales contribuciones al ambito de las matematicas. EnglishThis article outlines a profile of Newton as a man and as a scientist. In particular, some of his main contributions to the field of mathematics are described.

Ultraluminous X-ray sources (ULXs) are extragalactic X-ray emitters located off-centre of their host galaxy and with a luminosity in excess of a few 1039 erg s−1, if emitted isotropically1,2. The discovery of periodic modulation revealed that in some ULXs the accreting compact object is a neutron star3–7, indicating luminosities substantially above their Eddington limit. The most extreme object in this respect is NGC 5907 ULX-1 (ULX1), with a peak luminosity that is 500 times its Eddington limit. During a Chandra observation to probe a low state of ULX1, we detected diffuse X-ray emission at the position of ULX1. Its diameter is 2.7 ± 1.0 arcsec and contains 25 photons, none below 0.8 keV. We interpret this extended structure as an expanding nebula powered by the wind of ULX1. Its diameter of about 200 pc, characteristic energy of ~1.9 keV and luminosity of ~2 × 1038 erg s−1 imply a mechanical power of 1.3 × 1041 erg s−1 and an age of ~7 × 104 yr. This interpretation suggests that a genuinely super-Eddington regime can be sustained for timescales much longer than the spin-up time of the neutron star powering the system. As the mechanical power from a single ULX nebula can rival the injection rate of cosmic rays of an entire galaxy8, ULX nebulae could be important cosmic ray accelerators9. Diffuse X-ray emission is detected around an ultraluminous X-ray source, interpreted as a wind-powered expanding nebula. Its energetics suggests that a super-Eddington regime can be longer than the spin-up time of the central neutron star.

científico y profesional exclusivamente y puede contener información clínica sensible.Los editores no se responsabilizan de los contenidos de los autores.Dirigir las consultas sobre derechos y autorizaciones a ceir@psicoterapiarelacional.esGanimedes en el diván.Una perspectiva histórica de la etiología de la homosexualidad masculina desde el psicoanálisis. Danilo Magistrali 1 MadridLa relación entre el psicoanálisis y la homosexualidad ha sido problemática y ambigua.El pensamiento psicoanalítico sobre la homosexualidad masculina probablemente estuvo más influido por las inclinaciones personales y culturales de los autores analíticos que otros temas.Este artículo pretende describir brevemente los principales aspectos de la historia de este conflicto y aclarar las razones de esta ambigüedad, en una revisión no

espanolLa relacion entre el arte y las matematicas no parece evidente al principio, pero el entrelazamiento y la convergencia entre estas dos esferas de la cultura humana han sido numerosos, profundos y fructiferos a lo largo de la historia. Las matematicas han sido descritas como un arte motivado por la belleza, y pueden ser reconocidas en artes como la musica, la danza, la pintura, la arquitectura, la escultura y la moda. Este articulo se centra, sin embargo, en la presencia de las matematicas en las artes visuales. EnglishThe relationship between art and mathematics does not appear evident at first, but the convergence between these two spheres of human culture has been numerous, profound and fruitful throughout history. Mathematics has been described as an art motivated by beauty, and it can be recognized in arts such as music, dance, painting, architecture, sculpture, and fashion. This article focuses, however, on the presence of mathematics in the visual arts.

The relationship between psychoanalysis and homosexuality has been troublesome and ambiguous. Psychoanalytic thinking about male homosexuality was probably more culturally biased and in uenced by the personal inclinations of analytical authors than other subjects. This thesis rstly aims to be a history of this con ict and secondly to clarify the reasons of this ambiguity. Freud was ambiguous when, on the one hand, he declared that homosexuals were not sick and even defended their right to become psychoanalysts and, on the other hand, developed the conceptual basis of an etiopathological theory that considered homosexuality a block in the psychosexual development of an individual. A preliminary and fundamental question in writing a history of psychoanalytic theories of homosexuality is the following one: what is the meaning of the word homosexuality in psychoanalysis? Or rather, what are the characteristics of the anthropological type that psychoanalysis calls homosexual? Since the publication of the History of Sexuality by Michel Foucault, there have been numerous studies that help to answer this question. For Freud, the homosexual is the anthropological type described by the medical science in the late nineteenth century. He is the homosexual described by Kra t-Ebing, Schrenck-Notzing and Binet. Foucault explained how the medical imperialism of the late nineteenth century shaped the conception of sexuality and created new anthropological types, including the homosexual. The homosexual is now a species. Studies on the relationships between homosexuality and psychoanalysis are not numerous. Furthermore, very important authors such as Bion, Winnicott and Lacan have touched only tangentially the issue of homosexuality. Even fewer are the critical studies about the history of the psychoanalytic theories of homosexuality. The rst systematic study of the relationship between psychoanalysis and homosexuality is the book written by Kenneth Lewes The Psychoanalytic Theory of Male Homosexuality published in 1988. It may be the best book written on this theme. The author chooses not to analyze the positions of Jung, Fromm, Stekel and generally favors American authors. He does not include, in his discussion, the criticisms that Foucault addressed to the medical psychiatric discourse right in those years, so Lewes does not re ect on the meaning of homosexual as a clinical subject in psychoanalytic thought. Moreover, the history he presents ends with the beginning of what we have called the third phase of the psychoanalytic approach to homosexuality...

espanolEn este articulo se pretende hacer un recorrido de las pruebas logicas de la existencia de Dios con particular atencion al argumento ontologico. EnglishThis article aims to do a historical tour of the logical proofs of the existence of God with particular attention to the ontological argument.