Spatial proteomic and phospho-proteomic organization in three prototypical cell migration modes

BACKGROUND Tight spatio-temporal signaling of cytoskeletal and adhesion dynamics is required for localized membrane protrusion that drives directed cell migration. Different ensembles of proteins are therefore likely to get recruited and phosphorylated in membrane protrusions in response to specific cues. RESULTS HERE, WE USE AN ASSAY THAT ALLOWS TO BIOCHEMICALLY PURIFY EXTENDING PROTRUSIONS OF CELLS MIGRATING IN RESPONSE TO THREE PROTOTYPICAL RECEPTORS: integrins, recepor tyrosine kinases and G-coupled protein receptors. Using quantitative proteomics and phospho-proteomics approaches, we provide evidence for the existence of cue-specific, spatially distinct protein networks in the different cell migration modes. CONCLUSIONS The integrated analysis of the large-scale experimental data with protein information from databases allows us to understand some emergent properties of spatial regulation of signaling during cell migration. This provides the cell migration community with a large-scale view of the distribution of proteins and phospho-proteins regulating directed cell migration.

Cognitive Comparative Advantage and the Organization of Work: Lessons from Herbert Simon's Vision of the Future

In a marvelous but somewhat neglected paper, 'The Corporation: Will It Be Managed by Machines?' Herbert Simon articulated from the perspective of 1960 his vision of what we now call the New Economy the machine-aided system of production and management of the late twentieth century. Simon's analysis sprang from what I term the principle of cognitive comparative advantage: one has to understand the quite different cognitive structures of humans and machines (including computers) in order to explain and predict the tasks to which each will be most suited. Perhaps unlike Simon's better-known predictions about progress in artificial intelligence research, the predictions of this 1960 article hold up remarkably well and continue to offer important insights. In what follows I attempt to tell a coherent story about the evolution of machines and the division of labor between humans and machines. Although inspired by Simon's 1960 paper, I weave many other strands into the tapestry, from classical discussions of the division of labor to present-day evolutionary psychology. The basic conclusion is that, with growth in the extent of the market, we should see humans 'crowded into' tasks that call for the kinds of cognition for which humans have been equipped by biological evolution. These human cognitive abilities range from the exercise of judgment in situations of ambiguity and surprise to more mundane abilities in spatio-temporal perception and locomotion. Conversely, we should see machines 'crowded into' tasks with a well-defined structure. This conclusion is not based (merely) on a claim that machines, including computers, are specialized idiots-savants today because of the limits (whether temporary or permanent) of artificial intelligence; rather, it rests on a claim that, for what are broadly 'economic' reasons, it will continue to make economic sense to create machines that are idiots-savants.

Lake Son Kol geochemistry, µXRF, biogeochemistry and pollen record

In general, a moderate drying trend is observed in mid-latitude arid Central Asia since the Mid-Holocene, attributed to the progressively weakening influence of the mid-latitude Westerlies on regional climate. However, as the spatio-temporal pattern of this development and the underlying climatic mechanisms are yet not fully understood, new high-resolution paleoclimate records from this region are needed. Within this study, a sediment core from Lake Son Kol (Central Kyrgyzstan) was investigated using sedimentological, (bio)geochemical, isotopic, and palynological analyses, aiming at reconstructing regional climate development during the last 6000 years. Biogeochemical data, mainly reflecting summer moisture conditions, indicate predominantly wet conditions until 4950 cal. yr BP, succeeded by a pronounced dry interval between 4950 and 3900 cal. yr BP. In the following, a return to wet conditions and a subsequent moderate drying trend until present times are observed. This is consistent with other regional paleoclimate records and likely reflects the gradual Late Holocene diminishment of the amount of summer moisture provided by the mid-latitude Westerlies. However, climate impact of the Westerlies was apparently not only restricted to the summer season but also significant during winter as indicated by recurrent episodes of enhanced allochthonous input through snowmelt, occurring before 6000 cal. yr BP and at 5100-4350, 3450-2850, and 1900-1500 cal. yr BP. The distinct ~1500-year periodicity of these episodes of increased winter precipitation in Central Kyrgyzstan resembles similar cyclicities observed in paleoclimate records around the North Atlantic, likely indicating a hemispheric-scale climatic teleconnection and an impact of North Atlantic Oscillation (NAO) variability in Central Asia.

La minería transnacional y territorios posnacionales : un nuevo sentido histórico para Santa María, Catamarca

Este artículo versa sobre la relación entre la minería transnacional y la cuestión de la territorialidad vinculada a esta actividad. A medida que se abren fronteras, las relaciones sociales se vuelven más desterritorializadas, crece la búsqueda de las raíces culturales y nuevas experiencias locales se generan en respuesta a la emergencia de territorios posnacionales (Appadurai, 1999). Estas experiencias definen un nuevo sentido histórico para el oeste catamarqueño y Santa María – provincia de Catamarca, Argentina-, donde los sujetos sociales locales - situados históricamente en contextos de periferia del capitalismo global y nacional- mediatizan, interpelan y desnaturalizan algunas de las transformaciones espacio-temporales producidas a partir de la mega- minería en las últimas décadas, bajo un paradigma extractivista. Por su parte, los sujetos locales examinan su propia historia y analiza las conflictividades en torno a los recursos naturales, y en respuesta, constituyen territorios en red no articulados a los flujos globales del capital sino a espacios de resistencia.

Contaminación por fosfatos en el oasis bajo riego del río Mendoza

El oasis bajo riego del río Mendoza, en la provincia argentina del mismo nombre -al igual que casi todas las ciudades en la actualidadpresenta problemas de avance de la urbanización sobre las tierras agrícolas, multiplicidad de usuarios y disminución de la disponibilidad del recurso hídrico, tanto en cantidad como en calidad. Si bien se destinan esfuerzos e inversiones tendientes a asegurar la disponibilidad de agua (mejora de eficiencias, ahorro de agua) no pasa lo mismo en relación con la preservación de su calidad. La agricultura mendocina resulta víctima de la contaminación producida por la urbanización y la industria a través del vuelco (puntual y/o difuso) de sus efluentes a la red de riego. Estudios realizados en el Oasis Norte de Mendoza pusieron de manifiesto la existencia de altos niveles de contaminación fosfatada en las aguas del río Mendoza. El presente trabajo tuvo como objetivo evaluar la evolución espacio-temporal y detectar las fuentes de esta contaminación. Los resultados del diagnóstico basado en una serie de muestreos realizados en 2003 - 2009 ponen de relieve la existencia de una moderada contaminación por fosfatos en las aguas del río Mendoza que riegan el Oasis Norte provincial. Asimismo, se detectaron niveles considerablemente altos de fosfatos en tres sitios específicos del oasis: 1. la superficie regadía servida por los canales Cacique Guaymallén y Jocolí -se observa un incremento de seis veces el contenido de fosfatos del agua: de 0,2 mg L-1 (R I) a 1,2 mg L-1 (C II)-; en este último sitio sólo se riega un pequeño sector que se aproxima a las 7.300 ha; 2. la superficie regada por el Colector Pescara aguas abajo del punto D VIII (1.250 ha), en la que los valores medios arrojaron un contenido diecisiete veces mayor (8,5 mg L-1 ) que los del sitio D I (0,49 mg L-1 ) que recibe desagües agrícolas y urbano pluviales; 3. la zona del Bajo río Mendoza (en esta zona se registró un aumento de dieciséis veces más fosfatos entre la parte media y la cola del sistema, con valores medios de 0,2 mg L-1 en el sitio R II y de 3,25 mg L-1 en R III).

Chert intervals in DSDP and ODP sites (Table 1)

Radiolarian cherts in the Tethyan realm of Jurassic age were recently interpreted as resulting from high biosiliceous productivity along upwelling zones in subequatorial paleolatitudes the locations of which were confirmed by revised paleomagnetic estimates. However, the widespread occurrence of cherts in the Eocene suggests that cherts may not always be reliable proxies of latitude and upwelling zones. In a new survey of the global spatio-temporal distribution of Cenozoic cherts in Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) sediment cores, we found that cherts occur most frequently in the Paleocene and early Eocene, with a peak in occurrences at ~50 Ma that is coincident with the time of highest bottom water temperatures of the early Eocene climatic optimum (EECO) when the global ocean was presumably characterized by reduced upwelling efficiency and biosiliceous productivity. Cherts occur less commonly during the subsequent Eocene global cooling trend. Primary paleoclimatic factors rather than secondary diagenetic processes seem therefore to control chert formation. This timing of peak Eocene chert occurrence, which is supported by detailed stratigraphic correlations, contradicts currently accepted models that involve an initial loading of large amounts of dissolved silica from enhanced weathering and/or volcanism in a supposedly sluggish ocean of the EECO, followed during the subsequent middle Eocene global cooling by more vigorous oceanic circulation and consequent upwelling that made this silica reservoir available for enhanced biosilicification, with the formation of chert as a result of biosilica transformation during diagenesis. Instead, we suggest that basin-basin fractionation by deep-sea circulation could have raised the concentration of EECO dissolved silica especially in the North Atlantic, where an alternative mode of silica burial involving widespread direct precipitation and/or absorption of silica by clay minerals could have been operative in order to maintain balance between silica input and output during the upwelling-deficient conditions of the EECO. Cherts may therefore not always be proxies of biosiliceous productivity associated with latitudinally focused upwelling zones.

La concepción del tiempo de Henri Bergson : El alcance de sus críticas a la tradición y los límites de su originalidad

Bergson critica a la tradición filosófica el hecho de haber pensado el tiempo espacialmente, el hecho de atribuirle las notas del espacio: la homogeneidad, la divisibilidad y la simultaneidad. A través de un análisis de las concepciones de la temporalidad de Kant y Husserl, intentaremos limitar las críticas de Bergson para sugerir que la originalidad de la noción de durée no consiste en sus notas intrínsecas (la heterogeneidad, la continuidad y la sucesión), ni en la paradójica alianza que se pueda dar entre ellas (como lo revela la crítica de Bachelard), sino en la posición extrínseca de la noción en relación a las otras nociones del sistema.

La concepción del tiempo de Henri Bergson : El alcance de sus críticas a la tradición y los límites de su originalidad

Bergson critica a la tradición filosófica el hecho de haber pensado el tiempo espacialmente, el hecho de atribuirle las notas del espacio: la homogeneidad, la divisibilidad y la simultaneidad. A través de un análisis de las concepciones de la temporalidad de Kant y Husserl, intentaremos limitar las críticas de Bergson para sugerir que la originalidad de la noción de durée no consiste en sus notas intrínsecas (la heterogeneidad, la continuidad y la sucesión), ni en la paradójica alianza que se pueda dar entre ellas (como lo revela la crítica de Bachelard), sino en la posición extrínseca de la noción en relación a las otras nociones del sistema.

La concepción del tiempo de Henri Bergson : El alcance de sus críticas a la tradición y los límites de su originalidad

Bergson critica a la tradición filosófica el hecho de haber pensado el tiempo espacialmente, el hecho de atribuirle las notas del espacio: la homogeneidad, la divisibilidad y la simultaneidad. A través de un análisis de las concepciones de la temporalidad de Kant y Husserl, intentaremos limitar las críticas de Bergson para sugerir que la originalidad de la noción de durée no consiste en sus notas intrínsecas (la heterogeneidad, la continuidad y la sucesión), ni en la paradójica alianza que se pueda dar entre ellas (como lo revela la crítica de Bachelard), sino en la posición extrínseca de la noción en relación a las otras nociones del sistema.

Snow-pit measurements on Atka Bay landfast sea ice during ANT-Land 2012/2013 season

Up to now, snow cover on Antarctic sea ice and its impact on radar backscatter, particularly after the onset of freeze/thaw processes, are not well understood. Here we present a combined analysis of in situ observations of snow properties from the landfast sea ice in Atka Bay, Antarctica, and high-resolution TerraSAR-X backscatter data, for the transition from austral spring (November 2012) to summer (January 2013). The physical changes in the seasonal snow cover during that time are reflected in the evolution of TerraSAR-X backscatter. We are able to explain 76-93% of the spatio-temporal variability of the TerraSAR-X backscatter signal with up to four snowpack parameters with a root-mean-squared error of 0.87-1.62 dB, using a simple multiple linear model. Over the complete study, and especially after the onset of early-melt processes and freeze/thaw cycles, the majority of variability in the backscatter is influenced by changes in snow/ice interface temperature, snow depth and top-layer grain size. This suggests it may be possible to retrieve snow physical properties over Antarctic sea ice from X-band SAR backscatter.

The distributions, C- and O-isotopic compositions, and frequency of giant-ooids

Early Triassic oceans were characterized by deposition of a number of "anachronistic facies", including microbialites, seafloor carbonate cement fans, and giant ooids. Giant ooids were particularly prevalent in Lower Triassic sections across South China and exhibit unusual features that may provide insights into marine environmental conditions following the end-Permian mass extinction. The section at Moyang (Guizhou Province) contains abundant giant ooids ranging in size between 2 and 6 mm (maximum 12 mm) and exhibiting various cortical structures, including regular, deformed, compound, regenerated and "domed". Preservation of ooid cortical structure is generally good as indicated by petrographic observations, and trace element and carbon isotope analyses suggest that diagenesis occurred in a closed diagenetic system. All ooids exhibit fine concentric laminae, frequently alternating between light-colored coarsely crystalline and dark-colored finely crystalline layers probably reflecting variation in organic content or original mineralogy. Under scanning electron microscope, biomineralized filaments or biofilms and tiny carbonate fluorapatite (CFA) crystals are commonly found in the finely crystalline layers. We infer that the precipitation of CFA was related to adsorption of P via microbial activity on the surfaces of ooids following episodic incursions of deep waters rich in carbon dioxide, hydrogen sulfide and phosphate into shallow-marine environments. Giant ooid precipitation may have been promoted in shallow ramp settings during these events by increased watermass agitation and supersaturation with respect to calcium carbonate, as well as reduced carbonate removal rates through biotic skeletal formation. Spatio-temporal distribution data reveal that giant ooids were widespread in the Tethyan region during the Early Triassic, and that they were most abundant immediately after the end-Permian crisis and disappeared gradually as metazoans repopulated marine environments.

Snow depths of volcanic events and accumulation rates of firn cores from the IPY traverse, Antarctica

Volcanic signatures in ice-core records provide an excellent means to date the cores and obtain information about accumulation rates. From several ice cores it is thus possible to extract a spatio-temporal accumulation pattern. We show records of electrical conductivity and sulfur from 13 firn cores from the Norwegian-USA scientific traverse during the International Polar Year 2007-2009 (IPY) through East Antarctica. Major volcanic eruptions are identified and used to assess century-scale accumulation changes. The largest changes seem to occur in the most recent decades with accumulation over the period 1963-2007/08 being up to 25% different from the long-term record. There is no clear overall trend, some sites show an increase in accumulation over the period 1963 to present while others show a decrease. Almost all of the sites above 3200 m above sea level (asl) suggest a decrease. These sites also show a significantly lower accumulation value than large-scale assessments both for the period 1963 to present and for the long-term mean at the respective drill sites. The spatial accumulation distribution is influenced mainly by elevation and distance to the ocean (continentality), as expected. Ground-penetrating radar data around the drill sites show a spatial variability within 10-20% over several tens of kilometers, indicating that our drill sites are well representative for the area around them. Our results are important for large-scale assessments of Antarctic mass balance and model validation.