EROSIÓN LITORAL ENTRE ARBOLETES Y PUNTA SAN BERNARDO, COSTA CARIBE COLOMBIANA

    The present morphology and the inventory of the historical shoreline changes (1938-2005) between Arboletes and Punta San Bernardo evidenced a strong erosional trend along 160 of its 180km total-length, resulting in the disparition/retreat of numerous beaches, followed by the consequent fooding/erosion of the adjacent littoral terraces and mangrove swamps. In general terms, the littoral Arboletes-Punta San Bernardo retreated 30 to 100m during the last seven decades, at rates between 0.5 and 1.5 m/year; maximum values were found at some critical sectors in the Arboletes-Punta Brava shore segment where magnitudes of coastline retreat were in the order of 900-1.500m at erosion rates up to 70 m/year during the period 1960-1975. Shore erosion in the study area results both from marine and subaerial processes and the combina-tion of geological factors (neotectonism and effects of mud diapirism, minor stocks of sands, relative sea level rise, poor geotechnical characteristics of cliff´s rocks) and human interventions (intensive sand mining from beaches and rivers, land uses with inadequate water management practices, adverse effects of groins and other rigid structures of defense). The precise defnition of each one of these factors is necessary for planning the development of the area considering the future sea level rise associated to the Global Climate Change.   Key words: Colombia, Caribbean Coast, beach erosion, cliff erosion, groins    Las morfología actual y el inventario de cambios de la línea de costa (1938-2005) del litoral Arboletes-Punta San Ber­nardo evidencian su carácter fuertemente erosional, caracterizado a lo largo de su mayor longitud (160 de 180km) por la desaparición/retroceso de numerosas playas y la erosión/inundación consecuente de las terrazas litorales y/o pantanos de manglar adyacentes. En términos generales, el litoral Arboletes-Punta San Bernardo retrocedió entre 30 y 100m durante las siete últimas décadas, a tasas entre 0.5 y 1.5 m/año, superadas en varios sectores críticos (Arboletes-Punta Brava) en los cuales las magnitudes de la erosión fueron del orden de los 900-1.500m a velocidades de 70 m/año durante 1960-1975. La erosión litoral en la zona resulta tanto de procesos marinos como subaéreos, y de la combinación de factores geológicos (neotectonismo/diapirismo de lodos, pocos aportes arenosos, ascenso relativo del nivel del mar, características geotécnicas pobres de las rocas) y antrópicos -minería intensiva de arenas de playas y ríos, usos diversos sin manejo de aguas lluvias y residuales, efectos de es polones y obras de defensa. La defnición precisa de estos factores es necesaria para planifcar el desarrollo litoral considerando aspectos como el ascenso futuro del nivel del mar asociado al Cambio Climático Global.   Palabras clave: Colombia, Costa Caribe, erosión de playas, erosión de acantilados, espolones.     &nbsp

Canine semen (Canis familiaris) cryopreservation on french straw in Medellín, Antioquia

The objective of this work was to apply the canine semen cryopreservation methodology in French straw in Medellín-Antioquia. A seminal collection was carried out to eight adult canines, by gloved hand method, each ejaculate was assessed macroscopically and microscopically and subsequently diluted with Triladyl® with a final concentration of 80x106 sperm/ml. Semen samples were packed in 0.5 ml straws and a quick-freezing process was performed (nitrogen vapors for 25 minutes and then transferred directly to liquid nitrogen, french straw method). In fresh semen, a milky whitish appearance, a volume of 2.27 ml (± 1.40), a concentration of 388.5x106 sperm/mL (± 228.069), individual motility of 79% (± 4%) and vigor of 3.96 (± 0.327) were observed. 123 straws were obtained, of which 27 were taken randomly and individual motility (51 ± 19%) and vigor (2.89 ± 1.02) were evaluated. In conclusion, the application of the methodology of quick-freezing by french straw, using Triladyl® as a cryoprotectant, is suggested as an efficient protocol for cryopreservation of canine semen in Medellín-Antioquia.  El objetivo de este trabajo fue aplicar la metodología de criopreservación de semen canino en pajilla francesa en el municipio de Medellín- Antioquia. Se realizó una colecta seminal a ocho caninos adultos, por método de mano enguantada, cada eyaculado fue evaluado macroscópica y microscópicamente y posteriormente diluido con Triladyl® a una concentración final de 80 x 106 espermatozoides/ml. Se empacaron en pajillas de 0,5 ml y fueron sometidas a criopreservación con un descenso de temperatura rápido, sometiendo las pajillas a vapores de nitrógeno durante 25 minutos y luego transferidas directamente a nitrógeno líquido (método de pajilla francesa). En el semen fresco, se observó una apariencia blanquecina lechosa, un volumen de 2.27 ml (±1.40) una concentración de 388.5 x106 espermatozoides/ mL (±228.069), una motilidad individual de 79% (± 4%) y un vigor de 3.96 (±0.327). Se obtuvieron 123 pajillas, de las cuales se tomaron 27 aleatoriamente y se les evaluó la motilidad individual (51 ± 19%) y vigor (2.89 ± 1.02). En conclusión, la aplicación de la metodología de criopreservación rápida por pajilla francesa, usando Triladyl® como crioprotector, se sugiere como protocolo eficiente para la criopreservación de semen canino en el municipio de Medellín.  The objective of this work was to apply the canine semen cryopreservation methodology in French straw in Medellín-Antioquia. A seminal collection was carried out to eight adult canines, by gloved hand method, each ejaculate was assessed macroscopically and microscopically and subsequently diluted with Triladyl® with a final concentration of 80x106 sperm/ml. Semen samples were packed in 0.5 ml straws and a quick-freezing process was performed (nitrogen vapors for 25 minutes and then transferred directly to liquid nitrogen, french straw method). In fresh semen, a milky whitish appearance, a volume of 2.27 ml (± 1.40), a concentration of 388.5x106 sperm/mL (± 228.069), individual motility of 79% (± 4%) and vigor of 3.96 (± 0.327) were observed. 123 straws were obtained, of which 27 were taken randomly and individual motility (51 ± 19%) and vigor (2.89 ± 1.02) were evaluated. In conclusion, the application of the methodology of quick-freezing by french straw, using Triladyl® as a cryoprotectant, is suggested as an efficient protocol for cryopreservation of canine semen in Medellín-Antioquia

The Prognostic Significance of Whole Blood Global and Specific DNA Methylation Levels in Gastric Adenocarcinoma

Epigenetics, particularly DNA methylation, has recently been elucidated as important in gastric cancer (GC) initiation and progression. We investigated the clinical and prognostic importance of whole blood global and site-specific DNA methylation in GC. tests. Survival analyses were carried out using the Kaplan-Meier method and log rank test. A backward conditional Cox proportional hazards regression model was used to identify independent predictors of survival. = 0.02) respectively.Analysis of global and site-specific DNA methylation in peripheral blood by pyrosequencing provides quantitative DNA methylation values that may serve as important prognostic indicators

Asymptotically Lifshitz wormholes and black holes for Lovelock gravity in vacuum

Static asymptotically Lifshitz wormholes and black holes in vacuum are shown to exist for a class of Lovelock theories in d=2n+1>7 dimensions, selected by requiring that all but one of their n maximally symmetric vacua are AdS of radius l and degenerate. The wormhole geometry is regular everywhere and connects two Lifshitz spacetimes with a nontrivial geometry at the boundary. The dynamical exponent z is determined by the quotient of the curvature radii of the maximally symmetric vacua according to n(z^2-1)+1=(l/L)^2, where L corresponds to the curvature radius of the nondegenerate vacuum. Light signals are able to connect both asymptotic regions in finite time, and the gravitational field pulls towards a fixed surface located at some arbitrary proper distance to the neck. The asymptotically Lifshitz black hole possesses the same dynamical exponent and a fixed Hawking temperature given by T=z/(2^z pi l). Further analytic solutions, including pure Lifshitz spacetimes with a nontrivial geometry at the spacelike boundary, and wormholes that interpolate between asymptotically Lifshitz spacetimes with different dynamical exponents are also found.Comment: 19 pages, 1 figur

Subtyping of Clostridium difficile PCR ribotypes 591, 106 and 002, the dominant strain types circulating in Medellin, Colombia

We aimed to achieve a higher typing resolution within the three dominant Clostridium difficile ribotypes (591,106 and 002) circulating in Colombia. A total of 50 C. difficile isolates we had previously typed by PCR-ribotyping, representing the major three ribotypes circulating in Colombia, were analyzed. Twenty-seven isolates of ribotype 591, 12 of ribotype 106 and 11 of ribotype 002 were subtyped by multiple locus variable-number tandem-repeat analysis (MLVA). The presence of the PaLoc genes (tcdA/tcdB), toxin production in culture and antimicrobial susceptibility were also determined. From the total C. difficile ribotypes analyzed, 20 isolates (74%) of ribotype 591, nine (75%) of ribotype 106 and five (45.5%) of ribotype 002 were recovered from patients with Clostridium difficile infection (CDI). MLVA allowed us to recognize four and two different clonal complexes for ribotypes 591 and 002, respectively, having a summed tandem-repeat difference (STRD) 10. Six ribotype 591 and three ribotype 002 isolates belonging to a defined clonal complex were isolated on the same week in two different hospitals. All ribotypes harbored either tcdA+/tcdB+ or tcdA-/tcdB+ PaLoc genes. Moreover, 94% of the isolates were positive for toxin in culture. All isolates were susceptible to vancomycin and metronidazole, while 75% to 100% of the isolates were resistant to clindamycin, and less than 14.8% of ribotype 591 isolates were resistant to moxifloxacina. No significant differences were found among ribotypes with respect to demographic and clinical patients’ data; however, our results demonstrated a high molecular heterogeneity of C. difficile strains circulating in Colombia

Neutrinos below 100 TeV from the southern sky employing refined veto techniques to IceCube data

Many Galactic sources of gamma rays, such as supernova remnants, are expected to produce neutrinos with a typical energy cutoff well below 100 TeV. For the IceCube Neutrino Observatory located at the South Pole, the southern sky, containing the inner part of the Galactic plane and the Galactic Center, is a particularly challenging region at these energies, because of the large background of atmospheric muons. In this paper, we present recent advancements in data selection strategies for track-like muon neutrino events with energies below 100 TeV from the southern sky. The strategies utilize the outer detector regions as veto and features of the signal pattern to reduce the background of atmospheric muons to a level which, for the first time, allows IceCube searching for point-like sources of neutrinos in the southern sky at energies between 100 GeV and several TeV in the muon neutrino charged current channel. No significant clustering of neutrinos above background expectation was observed in four years of data recorded with the completed IceCube detector. Upper limits on the neutrino flux for a number of spectral hypotheses are reported for a list of astrophysical objects in the southern hemisphere

Search for transient optical counterparts to high-energy IceCube neutrinos with Pan-STARRS1

In order to identify the sources of the observed diffuse high-energy neutrino flux, it is crucial to discover their electromagnetic counterparts. IceCube began releasing alerts for single high-energy ($E > 60$ TeV) neutrino detections with sky localisation regions of order 1 deg radius in 2016. We used Pan-STARRS1 to follow-up five of these alerts during 2016-2017 to search for any optical transients that may be related to the neutrinos. Typically 10-20 faint ($m < 22.5$ mag) extragalactic transients are found within the Pan-STARRS1 footprints and are generally consistent with being unrelated field supernovae (SNe) and AGN. We looked for unusual properties of the detected transients, such as temporal coincidence of explosion epoch with the IceCube timestamp. We found only one transient that had properties worthy of a specific follow-up. In the Pan-STARRS1 imaging for IceCube-160427A (probability to be of astrophysical origin of $\sim$50 %), we found a SN PS16cgx, located at 10.0' from the nominal IceCube direction. Spectroscopic observations of PS16cgx showed that it was an H-poor SN at z = 0.2895. The spectra and light curve resemble some high-energy Type Ic SNe, raising the possibility of a jet driven SN with an explosion epoch temporally coincident with the neutrino detection. However, distinguishing Type Ia and Type Ic SNe at this redshift is notoriously difficult. Based on all available data we conclude that the transient is more likely to be a Type Ia with relatively weak SiII absorption and a fairly normal rest-frame r-band light curve. If, as predicted, there is no high-energy neutrino emission from Type Ia SNe, then PS16cgx must be a random coincidence, and unrelated to the IceCube-160427A. We find no other plausible optical transient for any of the five IceCube events observed down to a 5$\sigma$ limiting magnitude of $m \sim 22$ mag, between 1 day and 25 days after detection.Comment: 20 pages, 6 figures, accepted to A&

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With the observation of high-energy astrophysical neutrinos by the IceCube Neutrino Observatory, interest has risen in models of PeV-mass decaying dark matter particles to explain the observed flux. We present two dedicated experimental analyses to test this hypothesis. One analysis uses 6 years of IceCube data focusing on muon neutrino ‘track’ events from the Northern Hemisphere, while the second analysis uses 2 years of ‘cascade’ events from the full sky. Known background components and the hypothetical flux from unstable dark matter are fitted to the experimental data. Since no significant excess is observed in either analysis, lower limits on the lifetime of dark matter particles are derived: we obtain the strongest constraint to date, excluding lifetimes shorter than $10^{28}$ s at 90% CL for dark matter masses above 10 TeV