Multifactor Productivity and its Determinants: Al Empirical Analysis for Mexican Manufacturing.

We use data from the Annual Industrial Survey for 1996-2003. First, we estimate production functions by means of growth accounting exercises and panel data econometrics for the whole sector and for 14 comprehensive groups. Various measures of Multifactor Productivity (MFP) are constructed, as we consider diverse combinations of inputs with capital, labour, electricity and transport. This allows us to compare MFP growth rates between groups. Second, we analyse econometrically some of the determinants of MFP and Labour Productivity (LP) growth. We find that, on the one hand, there is some evidence of a positive relationship between market concentration and technology adoption; on the other hand, both technology adoption and human capital seem to be promoting productivity, whilst market concentration is exerting a negative influence on it. In sum, our results suggest that, once controlling for the effect on technology adoption, more concentration (conversely, less competition) has a negative impact on productivity.Panel data, Productivity, Manufacturing, Competition

Translog Cost Functions: An Application for Mexican Manufacturing.

We use translog cost functions to estimate own-price and substitution elasticities of input demands, economies of scale and average costs in Mexican manufacturing. Data from the Mexican Annual Industrial Survey is used for 1996, 2000 and 2003. We show that a model that allows for nonhomotheticity and nonunitary elasticities of substitution is appropriate to represent the production structure. Allen-Uzawa elasticities indicate the existence of substitution possibilities amongst inputs. The demand for electricity is essentially unitary elastic. All cross-price elasticities are less than one. Both scale economies and average costs diminish as the size of activity class increases. Economies of scale increased for any level of output. The differences in average costs between small and large activity classes were reduced and some disparities prevail in a number of manufacturing groups.Simultaneous equation models, Translog cost function, Manufacturing

Diversity across Seasons of Culturable Pseudomonas from a Desiccation Lagoon in Cuatro Cienegas, Mexico.

Cuatro Cienegas basin (CCB) is a biodiversity reservoir within the Chihuahuan desert that includes several water systems subject to marked seasonality. While several studies have focused on biodiversity inventories, this is the first study that describes seasonal changes in diversity within the basin. We sampled Pseudomonas populations from a seasonally variable water system at four different sampling dates (August 2003, January 2004, January 2005, and August 2005). A total of 70 Pseudomonas isolates across seasons were obtained, genotyped by fingerprinting (BOX-PCR), and taxonomically characterized by 16S rDNA sequencing. We found 35 unique genotypes, and two numerically dominant lineages (16S rDNA sequences) that made up 64% of the sample: P. cuatrocienegasensis and P. otitidis. We did not recover genotypes across seasons, but lineages reoccurred across seasons; P. cuatrocienegasensis was isolated exclusively in winter, while P. otitidis was only recovered in summer. We statistically show that taxonomic identity of isolates is not independent of the sampling season, and that winter and summer populations are different. In addition to the genetic description of populations, we show exploratory measures of growth rates at different temperatures, suggesting physiological differences between populations. Altogether, the results indicate seasonal changes in diversity of free-living aquatic Pseudomonas populations from CCB

High dispersion spectroscopy of two A supergiant systems in the Small Magellanic Cloud with novel properties

We present the results of a spectroscopic investigation of two novel variable bright blue stars in the SMC, OGLE004336.91-732637.7 (SMC-SC3) and the periodically occulted star OGLE004633.76-731204.3 (SMC-SC4), whose photometric properties were reported by Mennickent et al. (2010). High-resolution spectra in the optical and far-UV show that both objects are actually A + B type binaries. Three spectra of SMC-SC4 show radial velocity variations, consistent with the photometric period of 184.26 days found in Mennickent et al. 2010. The optical spectra of the metallic lines in both systems show combined absorption and emission components that imply that they are formed in a flattened envelope. A comparison of the radial velocity variations in SMC-SC4 and the separation of the V and R emission components in the Halpha emission profile indicate that this envelope, and probably also the envelope around SMC-SC3, is a circumbinary disk with a characteristic orbital radius some three times the radius of the binary system. The optical spectra of SMC-SC3 and SMC-SC4 show, respectively, HeI emission lines and discrete Blue Absorption Components (BACs) in metallic lines. The high excitations of the HeI lines in the SMC-SC3 spectrum and the complicated variations of FeII emission and absorption components with orbital phase in the spectrum of SMC-SC4 suggests that shocks occur between the winds and various static regions of the stars' co-rotating binary-disk complexes. We suggest that BACs arise from wind shocks from the A star impacting the circumbinary disk and a stream of former wind-efflux from the B star accreting onto the A star. We dub these objects prototype of a small group of Magellanic Cloud wind-interacting A + B binaries.Comment: To be published in MNRA

The abundance of Bullet-groups in LCDM

We estimate the expected distribution of displacements between the two dominant dark matter (DM) peaks (DM-DM displacements) and between DM and gaseous baryon peak (DM-gas displacements) in dark matter halos with masses larger than $10^{13}$ Msun/h. We use as a benchmark the observation of SL2S J08544-0121, which is the lowest mass system ($1.0\times 10^{14}$ Msun/h) observed so far featuring a bi-modal dark matter distribution with a dislocated gas component. We find that $(50 \pm 10)$% of the dark matter halos with circular velocities in the range 300 km/s to 700 km/s (groups) show DM-DM displacements equal or larger than $186 \pm 30$ kpc/h as observed in SL2S J08544-0121. For dark matter halos with circular velocities larger than 700 km/s (clusters) this fraction rises to 70 $\pm$ 10%. Using the same simulation we estimate the DM-gas displacements and find that 0.1 to 1.0% of the groups should present separations equal or larger than $87\pm 14$kpc/h corresponding to our observational benchmark; for clusters this fraction rises to (7 $\pm$ 3)%, consistent with previous studies of dark matter to baryon separations. Considering both constraints on the DM-DM and DM-gas displacements we find that the number density of groups similar to SL2S J08544-0121 is $\sim 6.0\times 10^{-7}$ Mpc$^{-3}$, three times larger than the estimated value for clusters. These results open up the possibility for a new statistical test of LCDM by looking for DM-gas displacements in low mass clusters and groups.Comment: 6 pages, 3 figures, accepted for publication in ApJ Letter

Bibliotecarios/as: sus aportes a la enseñanza de la lectura y la escritura en la educación primaria

Este artículo muestra parte de un trabajo de investigación en curso que ha tenido un recorrido en algunos encuentros y jornadas de didáctica de la lengua y la literatura como así también en el ámbito bibliotecológico. El hilo conductor de estas páginas es el trabajo de los bibliotecarios escolares o MB, sigla con la cual la Dirección de Escuelas de la provincia de Buenos Aires designa al cargo de maestro o maestra bibliotecaria/o de las escuelas primarias(en adelante, MB). En primer lugar, para hablar del trabajo de los y las MB se hace imprescindible abordar el tema de la biblioteca escolar (BE), como lugar físico y simbólico en el cual acontecen sus prácticas e intervenciones pedagógicas, por lo cual se presentan algunas ideas que circulan sobre cómo deberían ser las bibliotecas escolares, según las normativas y según algunos expertos o estudiosos del tema. En segundo lugar, se presenta una breve revisión de las normativas para el funcionamiento de la BE en consonancia con las capacitaciones para las y los MB de la provincia de Buenos Aires, para contrastarlo con lo que ocurre en las escuelas.Facultad de Humanidades y Ciencias de la Educació

The relationship among the Auletobius species of the subgenus Canarauletes and the description of a new species (Attelabidae: Rhynchitinae)

Eine neue Auletobius-Art des Subgenus Canarauletes, Auletobius gaditanus spec. nov., wird aus dem Süden Spaniens beschrieben. Die Meldung, dass die Schwesterart Auletobius maroccanus Hoffmann, 1953 (Locus typicus: Marokko, Reggou, Moyen Moulouya) ebenfalls in Spanien (Almeria: Punta del Sabinar) vorkommt, wird korrigiert. Auch bei diesem Nachweis handelt es sich zweifelsfrei um die neue, hier beschriebene Art, die in einer morphologischen und molekularen Differentialdiagnose (CO1) von den verwandten Arten aus Marokko, den Kanarischen Inseln und Madeira abgegrenzt wird. Für fast alle Canarauletes-Arten wird hier erstmalig ein molekulares Dendrogramm im Diskussionsteil vorgestellt.   Nomenklatorische Handlungen Auletobius gaditanus spec. nov. – urn:lsid:zoobank.org:act:17F6BFE9-974E-46B2-BA6E-05624044EAD7A new Auletobius species of the subgenus Canarauletes, Auletobius gaditanus spec. nov., is described from southern Spain. The report that the sister taxon Auletobius maroccanus Hoffmann, 1953 (Locus typicus: Morocco, Reggou, Moyen Moulouya) also occurs in Spain (Almeria: Punta del Sabinar) is corrected, because this specimen also belongs to the new species without doubt. In a morphological and molecular differential diagnosis, the new species is distinguished from the closest related species, and for the first time, a molecular relationship analysis (CO1) is presented for almost all species of the subgenus Canarauletes, whose main distribution area is in the Canary Islands and Madeira.   Taxonomic acts Auletobius gaditanus spec. nov. – urn:lsid:zoobank.org:act:17F6BFE9-974E-46B2-BA6E-05624044EAD

A Five-year Spectroscopic and Photometric Campaign on the Prototypical alpha Cygni Variable and A-type Supergiant Star Deneb

Deneb is often considered the prototypical A-type supergiant, and is one of the visually most luminous stars in the Galaxy. A-type supergiants are potential extragalactic distance indicators, but the variability of these stars needs to be better characterized before this technique can be considered reliable. We analyzed 339 high resolution echelle spectra of Deneb obtained over the five-year span of 1997 through 2001 as well as 370 Stromgren photometric measurements obtained during the same time frame. Our spectroscopic analysis included dynamical spectra of the H-alpha profile, H-alpha equivalent widths, and radial velocities measured from Si II 6347, 6371. Time-series analysis reveals no obvious cyclic behavior that proceeds through multiple observing seasons, although we found a suspected 40 day period in two, non-consecutive observing seasons. Some correlations are found between photometric and radial velocity data sets, and suggest radial pulsations at two epochs. No correlation is found between the variability of the H-alpha profiles and that of the radial velocities or the photometry. Lucy (1976) found evidence that Deneb was a long period single-lined spectroscopic binary star, but our data set shows no evidence for radial velocity variations caused by a binary companion.Comment: 49 pages, 9 figures, 5 tables, accepted for publication in the Astronomical Journa

Internal kinematics of spiral galaxies in distant clusters III. Velocity fields from FORS2/MXU spectroscopy

(Abridged) We study the impact of cluster environment on the evolution of spiral galaxies by examining their structure and kinematics. Rather than two-dimensional rotation curves, we observe complete velocity fields by placing three adjacent and parallel FORS2 MXU slits on each object, yielding several emission and absorption lines. The gas velocity fields are reconstructed and decomposed into circular rotation and irregular motions using kinemetry. To quantify irregularities in the gas kinematics, we define three parameters: sigma_{PA} (standard deviation of the kinematic position angle), Delta phi (the average misalignment between kinematic and photometric position angles) and k_{3,5} (squared sum of the higher order Fourier terms). Using local, undistorted galaxies from SINGS, these can be used to establish the regularity of the gas velocity fields. Here we present the analysis of 22 distant galaxies in the MS0451.6-0305 field with 11 members at z=0.54. In this sample we find both field (4 out of 8) and cluster (3 out of 4) galaxies with velocity fields that are both irregular and asymmetric. We show that these fractions are underestimates of the actual number of galaxies with irregular velocity fields. The values of the (ir)regularity parameters for cluster galaxies are not very different from those of the field galaxies, implying that there are isolated field galaxies that are as distorted as the cluster members. None of the deviations in our small sample correlate with photometric/structural properties like luminosity or disk scale length in a significant way. Our 3D-spectroscopic method successfully maps the velocity field of distant galaxies, enabling the importance and efficiency of cluster specific interactions to be assessed quantitatively.Comment: accepted for publication in A&A, high resolution version available at http://www.astro.rug.nl/~kutdemir/papers

Resultados generales

Aspecto externo Morfometría esquelética y masa Morfometría alar y caudal Tamaño Estructuras sexuales externas Determinación del sexo Neumatización craneal Muda Datación mediante variables semicuantitativas Ciclos vitale