Sites for Gamma-ray Astronomy in Argentina

We have searched for possible sites in Argentina for the installation of large air Cherenkov telescope arrays and water Cherenkov systems. At present seven candidates are identified at altitudes from 2500 to 4500 m. The highest sites are located at the Northwest of the country, in La Puna. Sites at 2500 and 3100 m are located in the West at El Leoncito Observatory, with excellent infrastructure. A description of these candidate sites is presented with emphasis on infrastructure and climatology.Comment: Submitted to Proceedings of "4th Heidelberg International Symposium on High Energy Gamma-Ray Astronomy 2008

Changes in Bone Mineral Density and Body Composition during lactation in adolescents

Se ha estudiado la Densidad Mineral Osea (DMO) de mujeres adultas durante la lactancia observándose pérdida con recuperación al año post parto. La Composición Corporal (CC) en este período ha evidenciado disminución de la Masa Grasa (MG) con preservación de la Masa Magra (MM). Estos datos son en mujeres adultas, no existiendo estudios de este tipo en adolescentes, que no han alcanzado el pico de masa ósea ni finalizado su crecimiento. Se estudiaron con Densitómetro LUNAR IQ y software pediátrico a 24 jóvenes de 16 años o menos que amamantaron a sus hijos por 1 año, con DMO de Columna (CL), Cuello femoral (CF), Cadera Total (CT), Contenido Mineral Oseo del esqueleto (CMO), y CC con MG y MM por Densitometría (DEXA) y por suma de pliegues. Resultados: Peso: 54.7 Kg (+/-5.1), Talla: 155 cm (+/-5.1), IMC: 23.0 (+/-2.0).Ingesta de calcio: 662,73 (+/-248) mg/d. Cambios (basal-3m-6m-12m): DMO CL %: 100- 98.1- 100.9- 106.5 # DMO CF %: 100- 94.1#- 94.6#- 97.7 DMO CT %: 100- 95.4#- 94.8#- 97.9 CMO esq %: 100- 97.2#- 96.9#- 98.3 % MG (DEXA): 35.4- 32.4- 29.4#- 27.5# % MG (pliegues): 30.1- 29.1- 27.9- 26.4# MM (Kg): 32.5- 32.5- 33.3 - 34.0 Peso: 54.6- 52.5- 51.4 – 50.9º #: p<0.001 vs basal º: p<0.01 La MG disminuyó (p<0.001) en brazos (2,75 Kg basal vs 1,60 Kg a los 12 meses), piernas (6,18 vs 4,92) y tronco (9,25 vs 6,57) todos p<0.001). Conclusiones: En adolescentes durante la lactancia la DMO CL no presenta pérdida y es mayor a los 12 meses. En CF, CT y CMO existe pérdida a los 3 y 6 meses con recuperación al año. La MM no cambia y la MG disminuye en todas las regiones y esto no afecta la recuperación de la masa ósea. Este aumento de DMO es auspicioso, más aún cuando ellas no tuvieron el aporte de calcio que se les indicó. Si volvieran a embarazarse inmediatamente (como ocurrió en tres casos) es posible que pierdan la oportunidad de continuar ganando calcio y alcanzar el pico de masa ósea.Bone Mineral Density (BMD) decreases in Lumbar Spine (LS) during lactation with recovery at six months of weaning. Studies about body composition showed that Fat Mass (FM) decreases during lactation and Lean Mass (LM) is preserved. These data is about adults. The objective of the work is study these changes during lactation in adolescents of 16 years or less. Patients and methods: we study prospectivly 24 adolescents during lactation at 15 days, 3,6 and 12 months after delivery. We measure weight, height, BMI, Body Composition by skinfold and DEXA with Fat Mass (FM) and Lean Mass (LM) in arms, legs and trunk, and BMD of Lumbar Spine (LS), Femoral Neck(FN) and Total Hip(TH), and Total Body Bone Mineral Content (BMC) with Lunar IQ with pediatric software. Results: Weight: 54.7 Kg(+/-5.1),Height: 155 cm (+/-5.1),BMI: 23.0 (+/-2.0).Calcium intake: 662,73 (+/-248) mg/d. Changes (basal-3m-6m-12m): BMD LS %: 100- 98.1- 100.9- 106.5 # BMD FN %: 100- 94.1#- 94.6#- 97.7 BMD TH %: 100- 95.4#- 94.8#- 97.9 BMC TB %: 100- 97.2#- 96.9#- 98.3 %FM(DEXA):35.4- 32.4- 29.4#- 27.5# %FM(SKIN):30.1- 29.1- 27.9 – 26.4# LM (KG): 32.5- 32.5- 33.3 - 34.0 WEIGHT: 54.6- 52.5- 51.4 – 50.9º # : p<0.001 vs basal º: p<0.01 Fat Mass diminish (p<0.001) en arms (2,75 Kg basal vs 1,60 Kg at 12 months),legs (6,18 vs 4,92) and trunk (9,25 vs 6,57) all p<0.001). Conclusions: In adolescents during lactation LS-BMD has no loss and is better at 12 months. In FN, TH and BMC there is bone loss with recovery. Lean Mass doesn't change. FM diminish in all regions but these change doesn't affect the bone recovery. These data is important because these women hasn't reached the peak of bone mass and many of them will have new pregancies before these moment.Facultad de Ciencias Médica

Changes in Bone Mineral Density and Body Composition during lactation in adolescents

Se ha estudiado la Densidad Mineral Osea (DMO) de mujeres adultas durante la lactancia observándose pérdida con recuperación al año post parto. La Composición Corporal (CC) en este período ha evidenciado disminución de la Masa Grasa (MG) con preservación de la Masa Magra (MM). Estos datos son en mujeres adultas, no existiendo estudios de este tipo en adolescentes, que no han alcanzado el pico de masa ósea ni finalizado su crecimiento. Se estudiaron con Densitómetro LUNAR IQ y software pediátrico a 24 jóvenes de 16 años o menos que amamantaron a sus hijos por 1 año, con DMO de Columna (CL), Cuello femoral (CF), Cadera Total (CT), Contenido Mineral Oseo del esqueleto (CMO), y CC con MG y MM por Densitometría (DEXA) y por suma de pliegues. Resultados: Peso: 54.7 Kg (+/-5.1), Talla: 155 cm (+/-5.1), IMC: 23.0 (+/-2.0).Ingesta de calcio: 662,73 (+/-248) mg/d. Cambios (basal-3m-6m-12m): DMO CL %: 100- 98.1- 100.9- 106.5 # DMO CF %: 100- 94.1#- 94.6#- 97.7 DMO CT %: 100- 95.4#- 94.8#- 97.9 CMO esq %: 100- 97.2#- 96.9#- 98.3 % MG (DEXA): 35.4- 32.4- 29.4#- 27.5# % MG (pliegues): 30.1- 29.1- 27.9- 26.4# MM (Kg): 32.5- 32.5- 33.3 - 34.0 Peso: 54.6- 52.5- 51.4 – 50.9º #: p<0.001 vs basal º: p<0.01 La MG disminuyó (p<0.001) en brazos (2,75 Kg basal vs 1,60 Kg a los 12 meses), piernas (6,18 vs 4,92) y tronco (9,25 vs 6,57) todos p<0.001). Conclusiones: En adolescentes durante la lactancia la DMO CL no presenta pérdida y es mayor a los 12 meses. En CF, CT y CMO existe pérdida a los 3 y 6 meses con recuperación al año. La MM no cambia y la MG disminuye en todas las regiones y esto no afecta la recuperación de la masa ósea. Este aumento de DMO es auspicioso, más aún cuando ellas no tuvieron el aporte de calcio que se les indicó. Si volvieran a embarazarse inmediatamente (como ocurrió en tres casos) es posible que pierdan la oportunidad de continuar ganando calcio y alcanzar el pico de masa ósea.Bone Mineral Density (BMD) decreases in Lumbar Spine (LS) during lactation with recovery at six months of weaning. Studies about body composition showed that Fat Mass (FM) decreases during lactation and Lean Mass (LM) is preserved. These data is about adults. The objective of the work is study these changes during lactation in adolescents of 16 years or less. Patients and methods: we study prospectivly 24 adolescents during lactation at 15 days, 3,6 and 12 months after delivery. We measure weight, height, BMI, Body Composition by skinfold and DEXA with Fat Mass (FM) and Lean Mass (LM) in arms, legs and trunk, and BMD of Lumbar Spine (LS), Femoral Neck(FN) and Total Hip(TH), and Total Body Bone Mineral Content (BMC) with Lunar IQ with pediatric software. Results: Weight: 54.7 Kg(+/-5.1),Height: 155 cm (+/-5.1),BMI: 23.0 (+/-2.0).Calcium intake: 662,73 (+/-248) mg/d. Changes (basal-3m-6m-12m): BMD LS %: 100- 98.1- 100.9- 106.5 # BMD FN %: 100- 94.1#- 94.6#- 97.7 BMD TH %: 100- 95.4#- 94.8#- 97.9 BMC TB %: 100- 97.2#- 96.9#- 98.3 %FM(DEXA):35.4- 32.4- 29.4#- 27.5# %FM(SKIN):30.1- 29.1- 27.9 – 26.4# LM (KG): 32.5- 32.5- 33.3 - 34.0 WEIGHT: 54.6- 52.5- 51.4 – 50.9º # : p<0.001 vs basal º: p<0.01 Fat Mass diminish (p<0.001) en arms (2,75 Kg basal vs 1,60 Kg at 12 months),legs (6,18 vs 4,92) and trunk (9,25 vs 6,57) all p<0.001). Conclusions: In adolescents during lactation LS-BMD has no loss and is better at 12 months. In FN, TH and BMC there is bone loss with recovery. Lean Mass doesn't change. FM diminish in all regions but these change doesn't affect the bone recovery. These data is important because these women hasn't reached the peak of bone mass and many of them will have new pregancies before these moment.Facultad de Ciencias Médica

The Pierre Auger Observatory III: Other Astrophysical Observations

Astrophysical observations of ultra-high-energy cosmic rays with the Pierre Auger ObservatoryComment: Contributions to the 32nd International Cosmic Ray Conference, Beijing, China, August 201

Highlights from the Pierre Auger Observatory

The Pierre Auger Observatory is the world's largest cosmic ray observatory. Our current exposure reaches nearly 40,000 km$^2$ str and provides us with an unprecedented quality data set. The performance and stability of the detectors and their enhancements are described. Data analyses have led to a number of major breakthroughs. Among these we discuss the energy spectrum and the searches for large-scale anisotropies. We present analyses of our X$_{max}$ data and show how it can be interpreted in terms of mass composition. We also describe some new analyses that extract mass sensitive parameters from the 100% duty cycle SD data. A coherent interpretation of all these recent results opens new directions. The consequences regarding the cosmic ray composition and the properties of UHECR sources are briefly discussed.Comment: 9 pages, 12 figures, talk given at the 33rd International Cosmic Ray Conference, Rio de Janeiro 201

Anisotropy and chemical composition of ultra-high energy cosmic rays using arrival directions measured by the Pierre Auger Observatory

The Pierre Auger Collaboration has reported evidence for anisotropy in the distribution of arrival directions of the cosmic rays with energies $E>E_{th}=5.5\times 10^{19}$ eV. These show a correlation with the distribution of nearby extragalactic objects, including an apparent excess around the direction of Centaurus A. If the particles responsible for these excesses at $E>E_{th}$ are heavy nuclei with charge $Z$, the proton component of the sources should lead to excesses in the same regions at energies $E/Z$. We here report the lack of anisotropies in these directions at energies above $E_{th}/Z$ (for illustrative values of $Z=6,\ 13,\ 26$). If the anisotropies above $E_{th}$ are due to nuclei with charge $Z$, and under reasonable assumptions about the acceleration process, these observations imply stringent constraints on the allowed proton fraction at the lower energies

Operations of and Future Plans for the Pierre Auger Observatory

Technical reports on operations and features of the Pierre Auger Observatory, including ongoing and planned enhancements and the status of the future northern hemisphere portion of the Observatory. Contributions to the 31st International Cosmic Ray Conference, Lodz, Poland, July 2009.Comment: Contributions to the 31st ICRC, Lodz, Poland, July 200

Measurement of the Depth of Maximum of Extensive Air Showers above 10^18 eV

We describe the measurement of the depth of maximum, Xmax, of the longitudinal development of air showers induced by cosmic rays. Almost four thousand events above 10^18 eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106 +35/-21) g/cm^2/decade below 10^(18.24 +/- 0.05) eV and (24 +/- 3) g/cm^2/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm^2. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.Comment: Accepted for publication by PR

Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter

Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuz'min energy threshold, \nobreak{$6\times 10^{19}$eV}. The anisotropy was measured by the fraction of arrival directions that are less than $3.1^\circ$ from the position of an active galactic nucleus within 75 Mpc (using the V\'eron-Cetty and V\'eron $12^{\rm th}$ catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is $(38^{+7}_{-6})$, compared with $21$ expected for isotropic cosmic rays. This is down from the early estimate of $(69^{+11}_{-13})$. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation.Comment: Accepted for publication in Astroparticle Physics on 31 August 201