El adolescente en la familia

An address before the staff of the Agricultural Extension Service during the training program offered in August 1956. How to cite: Núñez de Bunker, C. (1956). El adolescente en la familia. Pedagogía, 4(2), 23-32. Retrieved from https://revistas.upr.edu/index.php/educacion/article/view/17252Trabajo leído ante el personal del Servicio de Extensión Agrícola durante el programa de adiestramiento ofrecido en agosto de 1956. Cómo citar: Núñez de Bunker, C. (1956). El adolescente en la familia. Pedagogía, 4(2), 23-32. Recuperado a partir de https://revistas.upr.edu/index.php/educacion/article/view/1725

Propagation of high-energy cosmic rays in extragalactic turbulent magnetic fields: resulting energy spectrum and composition

We extend previous studies of mixed-composition extragalactic cosmic-ray source models, by investigating the influence of a non-negligible extragalactic magnetic field on the propagated cosmic-ray spectrum and composition. We study the transport of charged particles in turbulent fields and the transition from a ballistic to a diffusive propagation regime. We introduce a method allowing a fast integration of the particle trajectories, which allows us to calculate extragalactic cosmic-ray spectra in the general case, without using either the diffusive or the rectilinear approximation. We find that the main features of the mixed-composition models -- regarding the interpretation of the ankle and the non-monotonous evolution of the average cosmic-ray mass -- remain essentially unchanged as long as the magnetic field intensity does not exceed a few nG.Comment: 15 pages, 20 figure

Material implication of Chile’s economic growth: combining material flow accounting (MFA) and structural decomposition analysis

Over the last three decades, the economic integration of the Chilean economy into global markets has been taking place at a rapid pace. For example, in 1986, exports represented 29% of GDP while in 1996 they had increased to 38% of GDP. This period of time was characterized by strong economic growth with an average annual growth rate of about 10%. From a physical perspective, material requirements more than doubled from 220 to 500 million tons of direct material inputs (DMI) during the same decade (the rate of material growth requirements was around 13% per year). The main objective of this study is to explain the changes in DMI by using a structural decomposition analysis (SDA). The changes in material flow accounting (MFA) were broken down into the effects caused by changes in resource use per unit of output (material intensity effect), changes between and within sectors (structural change effect), changes in the composition of final demand (mix effect), changes due to shifting shares of domestic final demand and export categories (category effect) and finally changes in the overall level of economic activities (level effects). The results, as a percentage of the total level of DMI used in 1986, indicate that economic growth was the major source of material changes (109%). The material intensity and category effects explained 31% and 14% of the increase, respectively. The increase in the material intensity is mainly due to a declining quality of ores in copper production. However, these components were partly compensated by the structure (− 14%) and mix (− 13%) effects. Therefore, for a Southern American country such as Chile, the main causes of these changes in material consumption have been a combination of the nature of economic growth along with an increase in export production and material intensity of production

Collisional Semiclassical Aproximations in Phase-Space Representation

The Gaussian Wave-Packet phase-space representation is used to show that the expansion in powers of $\hbar$ of the quantum Liouville propagator leads, in the zeroth order term, to results close to those obtained in the statistical quasiclassical method of Lee and Scully in the Weyl-Wigner picture. It is also verified that propagating the Wigner distribution along the classical trajectories the amount of error is less than that coming from propagating the Gaussian distribution along classical trajectories.Comment: 20 pages, REVTEX, no figures, 3 tables include

CIRPASS near-infrared integral-field spectroscopy of massive star clusters in the starburst galaxy NGC 1140

[ABRIDGED] We analyse near-infrared integral field spectroscopy of the central starburst region of NGC 1140, obtained at the Gemini-South telescope equipped with CIRPASS. Our ~1.45-1.67 um wavelength coverage includes the bright [Fe II] emission line, as well as high-order Brackett (hydrogen) lines. While strong [Fe II] emission, thought to originate in the thermal shocks associated with supernova remnants, is found throughout the galaxy, both Br 12-4 and Br 14-4 emission, and weak CO(6,3) absorption, is predominantly associated with the northern starburst region. The Brackett lines originate from recombination processes occurring on smaller scales in (young) HII regions. The time-scale associated with strong [Fe II] emission implies that most of the recent star-formation activity in NGC 1140 was induced in the past 35-55 Myr. Based on the spatial distributions of the [Fe II] versus Brackett line emission, we conclude that a galaxy-wide starburst was induced several tens of Myr ago, with more recent starburst activity concentrated around the northern starburst region. This scenario is (provisionally) confirmed by our analysis of the spectral energy distributions of the compact, young massive star clusters (YMCs) detected in new and archival broad-band HST images. The YMC ages in NGC 1140 are all <= 20 Myr, consistent with independently determined estimates of the galaxy's starburst age, while there appears to be an age difference between the northern and southern YMC complexes in the sense expected from our CIRPASS analysis. Our photometric mass estimates of the NGC 1140 YMCs, likely upper limits, are comparable to those of the highest-mass Galactic globular clusters and to spectroscopically confirmed masses of (compact) YMCs in other starburst galaxies.Comment: 16 pages LaTeX, incl. 6 postscript figures; accepted for publication in MNRA

Interpreting high [O III]/H β ratios with maturing starbursts

Star-forming galaxies at high redshift show ubiquitously high-ionization parameters, as measured by the ratio of optical emission lines. We demonstrate that local (z < 0.2) sources selected as Lyman break analogues also manifest high line ratios with a typical [O III]/Hβ=3.36+0.14−0.04 – comparable to all but the highest ratios seen in star-forming galaxies at z ∼ 2–4. We argue that the stellar population synthesis code BPASS can explain the high-ionization parameters required through the ageing of rapidly formed star populations, without invoking any AGN contribution. Binary stellar evolution pathways prolong the age interval over which a starburst is likely to show elevated line ratios, relative to those predicted by single stellar evolution codes. As a result, model galaxies at near-solar metallicities and with ages of up to ∼100 Myr after a starburst typically have a line ratio [O III]/Hβ ∼ 3, consistent with those seen in Lyman break galaxies and local sources with similar star formation densities. This emphasises the importance of including binary evolution pathways when simulating the nebular line emission of young or bursty stellar populations

Dynamics of Lyman Break Galaxies and Their Host Halos

We present deep two-dimensional spectra of 22 candidate and confirmed Lyman break galaxies (LBGs) at redshifts 2<z<4 in the Hubble Deep Field (HDF) obtained at the Keck II telescope. The targets were preferentially selected with spatial extent and/or multiple knot morphologies, and we used slitmasks and individual slits tilted to optimize measurement of any spatially resolved kinematics. The median target magnitude was I_814=25.3, and total exposure times ranged from 10 to 50 ks. We measure redshifts, some new, ranging from z=0.2072 to z=4.056, including two interlopers at z<1, and resulting in a sample of 14 LBGs with a median redshift z=2.424. The morphologies and kinematics of the close pairs and multiple knot sources in our sample are generally inconsistent with galaxy formation scenarios postulating that LBGs occur only at the bottom of the potential wells of massive host halos; rather, they support ``collisional starburst'' models with significant major merger rates and a broad halo occupation distribution. For 13 LBGs with possible kinematic signatures, we estimate simple dynamical masses ranging from 4e9 h^-1 M_sun to 1.1e11 h^-1 M_sun for individual galaxies and from <10e10 h^-1 to ~10^14 h^-1 M_sun with a median value 1e13 h^-1 M_sun for host dark matter halos. Comparison with a recent numerical galaxy formation model implies that the pairwise velocities might not reflect true dynamical masses. We compare our dynamical mass estimates directly to stellar masses and find no evidence for a strong correlation. The diversity of morphologies and dynamics implies that LBGs represent a broad range of galaxy or proto-galaxy types in a variety of evolutionary or merger stages rather than a uniform class with a narrow range of mass.Comment: 64 pages, 8 figures; accepted for publication in ApJ. Full-res figures available at http://www.ast.smith.edu/james

The dynamics of quality: a national panel study of evidence-based standards

This is the final version of the article. Available from NIHR Health Technology Assessment Programme via the DOI in this record.Background Shortfalls in the receipt of recommended health care have been previously reported in England, leading to preventable poor health. Objectives To assess changes over 6 years in the receipt of effective health-care interventions for people aged 50 years or over in England with cardiovascular disease, depression, diabetes or osteoarthritis; to identify how quality varied with participant characteristics; and to compare the distribution of illness burden in the population with the distributions of diagnosis and treatment. Setting and participants Information on health-care quality indicators and participant characteristics was collected using face-to-face structured interviews and nurse visits in participants’ homes by the English Longitudinal Study of Ageing in 2004–5, 2006–7, 2008–9 and 2010–11. A total of 16,773 participants aged 50 years or older were interviewed at least once and 5114 were interviewed in all four waves; 5404 reported diagnosis of one or more of four conditions in 2010–11. Main outcome measures Percentage of indicated health care received by eligible participants for 19 quality indicators: seven for cardiovascular disease, three for depression, five for diabetes and four for osteoarthritis, and condition-level quality indicator achievement, including achievement of a bundle of three diabetes indicators. Analysis Changes in quality indicator achievement over time and variations in quality with participant characteristics were tested with Pearson’s chi-squared test and logistic regression models. The size of inequality between the hypothetically wealthiest and poorest participants, for illness burden, diagnosis and treatment, was estimated using slope indices of wealth inequality. Results Achievement of indicators for cardiovascular disease was 82.7% [95% confidence interval (CI) 79.9% to 85.5%] in 2004–5 and 84.2% (95% CI 82.1% to 86.2%) in 2010–11, for depression 63.3% (95% CI 57.6% to 69.0%) and 59.8% (95% CI 52.4% to 64.3%), for diabetes 76.0% (95% CI 74.1% to 77.8%) and 76.5% (95% CI 74.8% to 78.1%), and for osteoarthritis 31.2% (95% CI 28.5% to 33.8%) and 35.6% (95% CI 34.2% to 37.1%). Achievement of the diabetes care bundle was 67.8% (95% CI 64.5% to 70.9%) in 2010–11. Variations in quality by participant characteristics were generally small. Diabetes indicator achievement was worse in participants with cognitive impairment [odds ratio (OR) 0.5, 95% CI 0.4 to 0.7] and better in those living alone (OR 1.7, 95% CI 1.3 to 2.0). Hypertension care was better for those aged over 74 years (vs. 50–64 years) (OR 3.2, 95% CI 2.0 to 5.3). Osteoarthritis care was better for those with severe (vs. mild) pain (OR 1.8, 95% CI 1.4 to 2.2), limiting illness (OR 1.8, 95% CI 1.5 to 2.1), and obesity (OR 1.6, 95% CI 1.2 to 2.0). Previous non-achievement of the diabetes care bundle was the biggest predictor of non-achievement 2 years later (OR 3.3, 95% CI 2.2 to 4.7). Poorer participants were always more likely than wealthier participants to have illness burden (statistically significant OR 3.9 to 16.0), but not always more likely to be diagnosed or receive treatment (0.2 to 5.3). Conclusions Shortfalls in quality of care for these four conditions have persisted over 6 years, with only half of the level of indicated health care achieved for osteoarthritis, compared with the other three conditions. Quality for osteoarthritis improved slightly over time but remains poor. The relatively high prevalence of specific illness burden in poorer participants was not matched by an equally high prevalence of diagnosis or treatment, suggesting that barriers to equity may exist at the stage at diagnosis. Further research is needed into the association between quality and health system characteristics at the level of clinicians, general practices or hospitals, and regions. Linkage to routinely collected data could provide information on health service characteristics at the individual patient level.Funding for this study was provided by the Health Services and Delivery Research programme of the National Institute for Health Research

A search for clusters at high redshift - III. Candidate H-alpha emitters and EROs in the PKS 1138-262 proto-cluster at z=2.16

In this paper we present deep VLT multi wavelength imaging observations of the field around the radio galaxy PKS 1138-262 aimed at detecting and studying a (potential) proto-cluster centered at this radio source. PKS 1138-262 is a massive galaxy at z=2.16, located in a dense environment as indicated by optical, X-ray and radio observations. We had already found an over-density of Ly-alpha emitting galaxies in this field, consistent with a proto-cluster structure associated with the radio galaxy. In addition, we find 40 candidate H-alpha emitters that have nominal rest frame equivalent width > 25 Angstrom within 1.8 Mpc and 2000 km/s of the radio galaxy. Furthermore, we find 44 objects with I - K > 4.3. This number of extremely red objects (EROs) is about twice the number found in blank field ERO surveys, suggesting that some EROs in this field are part of the proto-cluster. The density of H-alpha emitters and extremely red objects increases towards the radio galaxy, indicating a physical association. From comparisons with other K band, ERO, H-alpha and Ly-alpha surveys, we conclude that PKS 1138-262 is located in a density peak which will evolve into a cluster of galaxies.Comment: Accepted by A&A (19/02/2004), 25 pages, 19 figure

Dynamical tunneling in molecules: Quantum routes to energy flow

Dynamical tunneling, introduced in the molecular context, is more than two decades old and refers to phenomena that are classically forbidden but allowed by quantum mechanics. On the other hand the phenomenon of intramolecular vibrational energy redistribution (IVR) has occupied a central place in the field of chemical physics for a much longer period of time. Although the two phenomena seem to be unrelated several studies indicate that dynamical tunneling, in terms of its mechanism and timescales, can have important implications for IVR. Examples include the observation of local mode doublets, clustering of rotational energy levels, and extremely narrow vibrational features in high resolution molecular spectra. Both the phenomena are strongly influenced by the nature of the underlying classical phase space. This work reviews the current state of understanding of dynamical tunneling from the phase space perspective and the consequences for intramolecular vibrational energy flow in polyatomic molecules.Comment: 37 pages and 23 figures (low resolution); Int. Rev. Phys. Chem. (Review to appear in Oct. 2007