1,921 research outputs found
Pubertad normal y variantes de la normalidad
La pubertad es un periodo de transición entre la infancia y la vida adulta, regulada por complejos mecanismos biológicos que, a su vez, están controlados por la interacción entre redes nodales de genes y el ambiente. Aunque ha existido una notable tendencia
secular en el inicio de la pubertad, desde el siglo XIX hasta mediados del siglo XX, esta se ha estabilizado en las Ăşltimas dĂ©cadas. De esta forma, se define como pubertad normal aquella que acontece entre los ocho y los trece años en las niñas y entre los nueve y catorce en los niños. El principal signo fĂsico a tener en cuenta para la valoraciĂłn del desarrollo puberal, es la apariciĂłn de telarquia progresiva en las niñas y el incremento
del tamaño testicular en los niños. Seguidamente, se desarrollarán otros caracteres sexuales secundarios y se objetivará un incremento de la velocidad del crecimiento. En el diagnĂłstico diferencial de trastornos de la pubertad, aparte de conocer los lĂmites normales de la pubertad, deberemos tener en cuenta una serie de variantes de la normalidad, como son: la adrenarquia prematura idiopática, la telarquia prematura aislada,
la pubertad adelantada y el retraso constitucional del crecimiento y pubertadPuberty is a transition period between childhood and adulthood regulated by complex biological mechanisms, which in turn are controlled by the interaction between gene networks
and environment. Although there has been a significant secular trend in onset of puberty from
the XIX century to the mid XX century, it has been stabilized in recent decades. Thus, it is defined normal puberty as that occurs between eight and thirteen years old in girls and between nine and fourteen years old in boys. The main physical sign to be considered for assessment of pubertal development is the emergence of progressive thelarche in girls and increased testicular size in boys. Then, other secondary sexual characteristics will develop and increased growth velocity will be observed. In the differential diagnosis of
puberty disorders, apart from knowing the normal limits of puberty, we must consider a number of variants of normality such as idiopathic premature adrenarche, premature thelarche, early puberty and constitutional delay of growth and pubert
A Conceptual Model of Referee Efficacy
This paper presents a conceptual model of referee efficacy, defines the concept, proposes sources of referee specific efficacy information, and suggests consequences of having high or low referee efficacy. Referee efficacy is defined as the extent to which referees believe they have the capacity to perform successfully in their job. Referee efficacy beliefs are hypothesized to be influenced by mastery experiences, referee knowledge/education, support from significant others, physical/mental preparedness, environmental comfort, and perceived anxiety. In turn, referee efficacy beliefs are hypothesized to influence referee performance, referee stress, athlete rule violations, athlete satisfaction, and co-referee satisfaction
Millimeter polarisation of the protoplanetary nebula OH 231.8+4.2: A follow-up study with CARMA
In order to investigate the characteristics and influence of the magnetic
field in evolved stars, we performed a follow-up investigation of our previous
submillimeter analysis of the proto-planetary nebula (PPN) OH 231.8+4.2 (Sabin
et al. 2014), this time at 1.3mm with the CARMA facility in polarisation mode
for the purpose of a multi-scale analysis. OH 231.8+4.2 was observed at ~2.5"
resolution and we detected polarised emission above the 3-sigma threshold (with
a mean polarisation fraction of 3.5 %). The polarisation map indicates an
overall organised magnetic field within the nebula. The main finding in this
paper is the presence of a structure mostly compatible with an ordered toroidal
component that is aligned with the PPN's dark lane. We also present some
alternative magnetic field configuration to explain the structure observed.
These data complete our previous SMA submillimeter data for a better
investigation and understanding of the magnetic field structure in OH
231.8+4.2.Comment: 7 pages, 5 figures, 2 tables. Accepted for publication in MNRA
Ring-shaped exact Hopf solitons
The existence of ring-like structures in exact hopfion solutions is shown.Comment: version accepted for publication in JMP, includes symmetry
transformation for finite paramete
The Global Crisis of 2007–2009: Markets, Politics, and Organizations
In this article, we examine the different causal chains leading to the crisis in the United States and around the world, emphasizing the market developments, political decisions, and organizational factors that led to the financial and economic meltdown. We argue that a series of political, regulatory, and organizational decisions and events prepared the ground for a major breakdown of financial and economic institutions, a “normal accident” that produced systemic reverberations across markets around the world. In the United States, political, regulatory, and organizational decisions made during the 1990s led to a situation of simultaneously high complexity and tight coupling in the financial system. The global economy also became more complex and tightly coupled during the 1990s, contributing to the rapid spread of the crisis across countries. We propose that solutions to the crisis will need to be tailored to the specific ways in which countries experienced the meltdown and the political preferences of interest groups and citizens. For the United States, the best approach would be to allow for a complex and innovative financial system but with a much reduced degree of coupling so as to avoid another financial normal accident
Investigation of the Nicole model
We study soliton solutions of the Nicole model - a non-linear
four-dimensional field theory consisting of the CP^1 Lagrangian density to the
non-integer power 3/2 - using an ansatz within toroidal coordinates, which is
indicated by the conformal symmetry of the static equations of motion. We
calculate the soliton energies numerically and find that they grow linearly
with the topological charge (Hopf index). Further we prove this behaviour to
hold exactly for the ansatz. On the other hand, for the full three-dimensional
system without symmetry reduction we prove a sub-linear upper bound,
analogously to the case of the Faddeev-Niemi model. It follows that symmetric
solitons cannot be true minimizers of the energy for sufficiently large Hopf
index, again in analogy to the Faddeev-Niemi model.Comment: Latex, 35 pages, 1 figur
Detection of a multi-shell planetary nebula around the hot subdwarf O-type star 2MASS J19310888+4324577
(Abridged) The origin of hot subdwarf O-type stars (sdOs) remains unclear
since their discovery in 1947. Among others, a post-Asymptotic Giant Branch
(post-AGB) origin is possible for a fraction of sdOs. We are involved in a
comprehensive ongoing study to search for and to analyze planetary nebulae
(PNe) around sdOs with the aim of establishing the fraction and properties of
sdOs with a post-AGB origin. We use deep Halpha and [OIII] images of sdOs to
detect nebular emission and intermediate resolution, long-slit optical
spectroscopy of the detected nebulae and their sdO central stars. These data
are complemented with other observations for further analysis of the detected
nebulae. We report the detection of an extremely faint, complex PN around 2MASS
J19310888+4324577 (2M1931+4324), a star classified as sdO in a binary system.
The PN shows a bipolar and an elliptical shell, whose major axes are oriented
perpendicular to each other, and high-excitation structures outside the two
shells. WISE archive images show faint, extended emission at 12 and 22 microns
in the inner nebular regions. The internal nebular kinematics is consistent
with a bipolar and a cylindrical/ellipsoidal shell, in both cases with the main
axis mainly perpendicular to the line of sight. The nebular spectrum only
exhibits Halpha, Hbeta and [OIII]4959,5007 emission lines, but suggests a very
low-excitation ([OIII]/Hbeta = 1.5), in strong contrast with the absence of
low-excitation emission lines. The spectrum of 2M1931+4324 presents narrow,
ionized helium absorptions that confirm the previous sdO classification and
suggest an effective temperature >= 60000 K. The binary nature of 2M1931+4324,
its association with a complex PN, and several properties of the system provide
strong support for the idea that binary central stars are a crucial ingredient
in the formation of complex PNe.Comment: 8 pages, 7 figures, accepted in Astronomy and Astrophysic
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