Sigmodontinos fósiles (rodentia, muroidea, sigmodontinae) de América del Sur : estado actual de su conocimiento y prospectiva

Fil: Pardiñas, Ulyses Francisco José. Departamento Científico Paleontología Vertebrados; Museo de La PlataFil: D`Elía, Guillermo. University of Michigan Museum of Zoology; Ann Arbor; USAFil: Ortiz, Pablo E.. Cátedra de Paleozoología II; Facultad de Ciencias Naturales e Instituto Miguel Lillo; Miguel Lillo 205; 4000 San Miguel de Tucumán; Argentin

Adaptation to osmotic stress provides protection against ammonium nitrate in Pelophylax perezi embryos

The negative effects of pollution on amphibians are especially high when animals are additionally stressed by other environmental factors such as water salinity. However, the stress provoked by salinity may vary among populations because of adaptation processes. We tested the combined effect of a common fertilizer, ammonium nitrate (0–90.3 mg N–NO3NH4/L), and water salinity (0–2‰) on embryos of two Pelophylax perezi populations from ponds with different salinity concentrations. Embryos exposed to the fertilizer were up to 17% smaller than controls. Survival rates of embryos exposed to a single stressor were always below 10%. The exposure to both stressors concurrently increased mortality rate (>95%) of embryos from freshwater. Since the fertilizer was lethal only when individuals were stressed by the salinity, it did not cause lethal effects on embryos naturally adapted to saline environments. Our results underscore the importance of testing multiple stressors when analyzing amphibian sensitivity to environmental pollution.Funding was provided by the Regional Government of Castilla y León (SA071A06) and the Ministry of Science and Innovation of Spain (CGL2005-0372).Peer reviewe

Organic matter accumulation during the Holocene in the Guadalquivir marshlands (SW Spain)

The distribution of biomarker compounds and magnetic susceptibility observed in the sediment from a 20 m core drilled in the marshlands of the estuarine region of the Guadalquivir River (southwest coast of Spain) has allowed us to reconstruct the palaeoenvironmental evolution of this area during the Holocene. Several organic compounds (n-alkanes, ra-ketones, n-alkanols, n-alkanoic acids and organic sulphur), as well as different biomarker ratios, have been used to show changing environmental conditions through time. These geochemical proxies suggest good preservation of the organic matter, although some diagenesis has occurred to particular organic compounds, especially the n-alkanoic acids. Our data indicate a major allochthonous supply of terrestrial plants, with less influence from aquatic plants or algae through the core. There are markedly different palaeoenvironmental conditions between the uppermost 5 m (last 6ka cal. B.P.) and the rest of the core. From 5 m (ca 6ka cal. B.P.) to 19 m (ca 8ka cal. B.P.) depth the palaeoenvironmental conditions were almost constant. Based on organic sulphur content and n-alkane content logs, anoxic conditions prevailed from 8 to 6ka cal. B.P., while oxic conditions with enhanced convection of water (prevalence of fluvial input), and consequently a greater organic matter supply, predominated in the upper 5 m of the core. Similarly, little variation in the magnetic susceptibility profile below 5 m indicates stable environmental conditions, while in the upper 5 m conditions shifted to one with elevated water input and clastic sediment supply. This is linked to palaeofloral alterations in the Guadiamar/Guadalquivir drainage basins and/or anthropogenic effects. We propose that from ca 8 to 6 ka cal. B.P. a stable landscape physiognomy in the surroundings of the estuarine area of the Guadalquivir River, with a predominance of pines and grassland. However, over the last 6ka cal. B.P. a variation in the terrestrial plant biomarker compounds suggests an alternation of relatively dry and humid phases and/or the impact of human populations on altering the vegetation community have occurred

Influence of a combination of agricultural chemicals on embryos of the endangered gold-striped salamander (Chioglossa lusitanica)

Pollution from agrochemicals may be contributing to the global decline of amphibian populations. Environmentally relevant concentrations of a fertiliser, ammonium nitrate, and a commercial formulation of the herbicide glyphosate Roundup Plus were tested on the embryonic development of Chioglossa lusitanica. This study introduces new data at three different levels. First, we provide previously unknown information about hatchling traits of C. lusitanica. Second, we present the first ecotoxicological study of this endangered species, to which environmental pollution is considered a major threat. Third, we conduct the first experiment with an amphibian species exposed to a mixture of a glyphosate-based herbicide and a nitrogenous fertiliser. Control individuals hatched with an average (±SD) total length of 18.77 (±2.02) mm and at an average Harrison’s developmental stage of 44.58 (±1.24). Mean hatching time among controls was 11.52 (±1.29) weeks. None of the chemicals or their interaction produced lethal effects; however, a significant interaction was found when analysing total length at hatching. Individuals exposed to the herbicide hatched at a larger size than controls, and this effect was especially clear when the fertiliser was added to the water. The absence of pollutant-related mortality or severe sublethal effects is in agreement with most studies indicating a high tolerance of amphibian embryos to agrochemicals. However, further research considering other life stages and additional natural factors (i.e., predators, food availability) is needed to estimate the ecological impact of chemical mixtures on C. lusitanica.Peer reviewe

Mathematical modeling, linear programming and videos in the training of engineers

Este estudio se llevó a cabo, utilizando el paradigma de investigación basado en diseño, abordando desde las etapas de desarrollo e implementación, un experimento de enseñanza con actividades de modelización matemática, utilizando Programación Lineal. Los participantes fueron estudiantes del sexto semestre de la carrera de Ingeniería de Procesos Industriales de la Universidad Central de Venezuela. El experimento de enseñanza se realizó utilizando la modalidad a distancia y aprovechando las bondades del aprendizaje móvil, entre otros, durante un período de seis semanas, con el apoyo de videos de contenido teórico-práctico a fin de fomentar el aprendizaje cooperativo y significativo. Los resultados del estudio demostraron que, en condiciones de no presencialidad, los estudiantes desarrollaron competencias de modelización matemática en la resolución de problemas contextuales con sentido crítico en el manejo y gestión de recursos limitados y uso de tecnología.This study was made under the research paradigm based on design, approaching from the development and implementation stages, a teaching experiment with mathematical modeling activities, using Linear Programming. The participants were students of the sixth semester of the Industrial Process Engineering career at the Central University of Venezuela. The teaching experiment was carried out using the distance modality and taking advantage of the benefits of mobile learning, among others, during a period of six weeks, with the support of videos with theoretical-practical content in order to promote cooperative and meaningful learning. The results of the study showed that in non-attendance conditions, students developed mathematical modeling skills in solving contextual problems with a critical sense in the handling and management of limited resources and use of technology

Conformationally-Locked C-Glycosides: Tuning Aglycone Interactions for Optimal Cheperone Behaviour in Gaucher Fibroblasts

A series of conformationally locked C-glycosides based on the 3-aminopyrano[3,2-b]pyrrol-2(1H)-one (APP) scaffold has been synthesized. The key step involved a totally stereocontrolled C-Michael addition of a serine-equivalent C-nucleophile to tri-O-benzyl-2-nitro-D-galactal, previously published by the authors. Stereoselective transformations of the Michael adduct allowed us the synthesis of compounds with mono- or diantennated aglycone moieties and different topologies. In vitro screening showed highly selective inhibition of bovine liver β-glucosidase/β-galactosidase and specific inhibition of human β-glucocerebrosidase among lysosomal glycosidases for compounds bearing palmitoyl chains in the aglycone, with a marked dependence of the inhibition potency upon their number and location. Molecular dynamics simulations highlighted the paramount importance of an optimal orientation of the hydrophobic substituent to warrant efficient non-glycone interactions, which are critical for the binding affinity. The results provide a rationale for the strong decrease of the inhibition potency of APP compounds on going from neutral to acidic pH. The best candidate was found to behave as pharmacological chaperone in Gaucher fibroblasts with homozygous N370S and F213I mutations, with enzyme activity enhancements similar to those encountered for the reference compound AmbroxolMinisterio de Economía y Competitividad CTQ2012-36365, SAF2013-44021-RJunta de Andalucía FQM-1467European Union Seventh Framework Programme FP7-People-2012-CI

A Functional Movement Screening on 6th Grade Students of a Caribbean Elementary Laboratory School

The purpose of this study was to examine the functional body movement of sixth grade students of a Caribbean Elementary Laboratory School. A total sample of 39 students, including special education, participated in the study. The Functional Movement Screening Test was used to identify the functional movement body profile of the students and the strength and areas to be improved in their body movement after completing a Physical Education Program K6. The participants completed a series of movement exercises (Deep Squat, Hurdle Step, Inline Lunge, Shoulder Mobility, Active Straight-Leg Raise, Trunk Stability Pushup, and Rotary Stability) of seven different skills of the Functional Movement Screening (FMS). An independent t-test analysis and descriptive data was used to analyses the collect data. The findings of the study show that 87.3% students from the Elementary Laboratory School of the University of Puerto Rico scores 14 points or more on the Functional Movement Test. The results of the study reflect that students of laboratory school that experiences different learning practices in Physical Education Program benefits their body functional movement

Improvement in PWV estimation from GPS due to the absolute calibration of antenna phase center variations

Climatology of column-integrated atmospheric water vapor over Spain has been carried out by means of three techniques: soundings, sun photometers and GPS receivers. Comparing data from stations equipped with more than one of these instruments, we found that a large discontinuity occurred on November 6, 2006, in the differences between the data series from GPS receivers and those from the other two techniques. Prior to that date, the GPS data indicate a wet bias of 2–3 mm for all stations when compared with sounding or photometer data, whereas after that date this bias practically reduces to zero. The root mean square error also decreases about half of its value. On November 6, 2006, the International GNSS Service adopted an absolute calibration model for the antennas of the GPS satellites and receivers instead of the relative one. This change is expected to be an improvement, increasing the accuracy of station position determination and consequently benefiting post-processing products such as zenith total delay from which the atmospheric water vapor content is calculated

Columnar aerosol characterization over Scandinavia and Svalbard

An overview of sun photometer measurements of aerosol properties in Scandinavia and Svalbard was provided by Toledano et al. (2012) thanks to the collaborative effort of various research groups from different countries that maintain a number of observation sites in the European Arctic and sub-Arctic regions. The spatial coverage of this kind of data has remarkably improved in the last years, thanks, among other things, to projects carried out within the framework of the International Polar Year 2007-08. The data from a set of operational sun photometer sites belonging either to national or international measurement networks (AERONET, GAW-PFR) were evaluated. The direct sun observations provided spectral aerosol optical depth (AOD) and Ångström exponent (AE), that are parameters with sufficient long-term records for a first characterization at all sites. At the AERONET sites, microphysical properties derived from inversion of sun-sky radiance data were also examined. AOD (500nm) ranged from 0.08 to 0.10 in Arctic and sub-Arctic sites whereas the aerosol load was higher in more populated areas in Southern Scandinavia (average AOD about 0.10–0.12 at 500 nm).Financial support was provided by: the Spanish CICYT (CGL2008-05939-CO3-01/CLI, CGL2009-09740 and CGL2011-13085-E); the Norwegian Research Council for POLARCAT-Norway; and the Swedish National Space Board and ESA for Norrköping and Palgrunden sites. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement Nr. 262254 [ACTRIS]

Pleistocene terracing phases in the metropolitan area of Bari - AAR dating and deduced uplift rates of the Apulian Foreland

We performed detailed geological and geomorphological analyses on a series of marine terraces located around the city of Bari (southern Italy). Absolute dating was obtained by applying amino acid racemisation (AAR) to ostracod valves taken from deposits lying on marine terraces. The combination of literature data, feld geological surveys, digital terrain model analysis, and absolute dating allowed us to recognise and map: i) four terrace surfaces bordered by four inner edges which date to MIS 7.5, 7.3, 7.1, and 5.5; and ii) three terraced deposits, which date to MIS 7.5, 7.1, and 5.5. These new data represent the frst dated terraced deposits (older than MIS 5) of the coastal stretch of the Apulian foreland between Trani and Taranto. Using inner edges of the terraces as palaeo sea level markers, we calculate the mean uplift rates that characterised this portion of the Apulian foreland from MIS 7.5, 7.3, 7.1, 5.5 to the present day; these rates are 0.28, 0.255, 0.15 and 0.01 mm/y, respectively. These new dated Pleistocene terraced deposits allow to refne the knowledge on the chronology, the spatial extension and rate of the uplift and, in general, on the Pleistocene geodynamics of the Apulian foreland