Catching Conical Intersections in the Act; Monitoring Transient Electronic Coherences by Attosecond Stimulated X-Ray Raman Signals

Conical intersections (CoIn) dominate the pathways and outcomes of virtually all photophysical and photochemical molecular processes. Despite extensive experimental and theoretical effort, CoIns have not been directly observed yet and the experimental evidence is being inferred from fast reaction rates and some vibrational signatures. We show that short X-ray (rather than optical) pulses can directly detect the passage through a CoIn with the adequate temporal and spectral sensitivity. The technique is based on a coherent Raman process that employs a composite femtosecond/attosecond X-ray pulse to detect the electronic coherences (rather than populations) that are generated as the system passes through the CoIn

The regional-scale surface mass balance of Pine Island Glacier, West Antarctica, over the period 2005--2014, derived from airborne radar soundings and neutron probe measurements

We derive recent surface mass balance (SMB) estimates from airborne radar observations along the iSTAR traverse (2013, 2014) at Pine Island Glacier (PIG), West Antarctica. Ground-based neutron probe measurements provide information of snow and firn density with depth at 22 locations and were used to date internal annual reflection layers. The 2005 layer was traced for a total distance of 2367 km to determine annual mean SMB for the period 2005–2014. Using complementary SMB estimates from two regional climate models, RACMO2.3p2 and MAR, and a geostatistical kriging scheme, we determine a regional-scale SMB distribution with similar main characteristics to that determined for the period 1985–2009 in previous studies. Local departures exist for the northern PIG slopes, where the orographic precipitation shadow effect appears to be more pronounced in our observations, and the southward interior, where the SMB gradient is more pronounced in previous studies. We derive total mass inputs of 79.9 +/- 19.2 and 82.1 +/- 19.2 Gt yr-1 to the PIG basin based on complementary ASIRAS–RACMO and ASIRAS–MAR SMB estimates, respectively. These are not significantly different to the value of 78.3 +/- 6.8 Gt yr-1 for the period 1985–2009. Thus, there is no evidence of a secular trend at decadal scales in total mass input to the PIG basin. We note, however, that our estimated uncertainty is more than twice the uncertainty for the 1985–2009 estimate on total mass input. Our error analysis indicates that uncertainty estimates on total mass input are highly sensitive to the selected krige methodology and assumptions made on the interpolation error, which we identify as the main cause for the increased uncertainty range compared to the 1985–2009 estimates

Freshwater Mussel Shells as Environmental Chronicles: Geochemical and Taphonomic Signatures of Mercury-Related Extirpations in the North Fork Holston River, Virginia

This study utilized freshwater mussel shells to assess mercury (Hg) contamination in the North Fork Holston River that extirpated (caused local extinctions of) a diverse mussel fauna. Shells (n = 366) were collected from five sites situated upstream (two sites), just below (one site), and downstream (two sites) of the town of Saltville, Virginia, where Hg was used to produce chlorine and caustic soda from 1950 to 1972. Shell samples were used to test the (1) utility of geochemical signatures of shells for assessing the spatial variation in Hg levels in the river relative to the contamination source and (2) value of taphonomy (post-mortem shell alteration) for distinguishing sites that differ in extirpation histories. Geochemical signatures of 40 shells, analyzed using atomic absorption spectroscopy, indicated a strong longitudinal pattern. All shells from the two upstream sites had low Hg concentrations (<5−31 μg/kg), shells directly below Saltville had variable, but dramatically higher concentrations (23−4637 μg/kg), and shells from the two downstream sites displayed intermediate Hg levels (<5−115 μg/kg) that declined with distance from Saltville. Two pre-industrial shells, collected at Saltville in 1917, yielded very low Hg estimates (5−6 μg/kg). Hg signatures were consistent among mussel species, suggesting that Hg concentrations were invariant to species type; most likely, highly variable Hg levels, both across sites and through time, overwhelmed any interspecific differences in Hg acquisition. Also, a notable post-mortem incorporation of Hg in mussel shells seemed unlikely, as the Hg content was not correlated with shell taphonomy (r = 0.18; p = 0.28). The taphonomic analysis (n = 366) showed that the degree of shell alteration reliably distinguished sites with different extirpation histories. At Saltville, where live mussels have been absent for at least 30 years, shells were most heavily altered and fragmented. Conversely, fresh-looking shells abounded upstream, where reproducing mussel populations are still present. In summary, relic shells offered valuable spatio-temporal data on Hg concentrations in a polluted ecosystem, and shell taphonomic signatures discriminated sites with different extirpation histories. The shell-based strategies exemplified here do not require sampling live specimens and may augment more standard strategies applied to environmental monitoring. The approach should prove especially useful in areas with unknown extirpation and pollution histories

Influence of surgical resection no plasma Endoglin (CD105) level in non-small cell lung cancer patients

Background and Aim: Endoglin is a proliferation-associated antigen on endothelial cells and essential for angiogenesis. Soluble endoglin (s‑endoglin), formed by proteolytic cleavage of ectodomain of membrane receptor could be an indicator of tumor‑activated endothelium. The aim of present study was to analyze changes of s‑endoglin level in plasma of lung cancer patients following surgical resection and to estimate the correlation of s‑endoglin with other soluble receptors, sTie2 and sVEGF R1. Patients and Methods: The study group consisted of 37 patients with stage I of non-small cell lung cancer. Plasma concentrations of s‑endoglin, sTie2 and sVEGF R1 were evaluated by ELISA, three times: before surgical resection and on postoperative day 7 and 30. Results: The median of s‑endoglin concentration decreased significantly on postoperative day 7 when compared with preoperative level and next increased on 30th day and it was comparable with that before surgery. s-Endoglin correlated with another soluble receptors, with sTie2 both before surgery (r=0.44) and on postoperative day 7 (r=0.52) and on 30th day (r=0.58), with sVEGF R1 — only on postoperative day 7 (r=0.75). Conclusion: The increased level of serum endoglin in lung cancer patients compared to controls and its changes after surgical treatment suggest potential application of soluble form of endoglin as potential tumor marker

Relaciones entre el hábitat, demografía y organización social en monos aulladores negros

Los estudios de primates del Nuevo Mundo han sido escasamente abordados dentro de la antropología biológica, ya que no ocupan lugares importantes en estudios de evolución humana. Sin embargo, los estudios evolutivos, deberían incluir comparaciones entre primates para dilucidar principios generales aplicables a todo el Orden. Tras varios años de investigación sobre Alouatta caraya, en Argentina, se encontró que la organización social, la densidad y los patrones de nacimientos varían en ambientes con diferentes ofertas alimenticias. Por un lado, la comparación en cinco sitios diferentes mostró diferencias significativas en tamaño de grupo y densidad de primates que correlacionaron con la disponibilidad de especies con frutos carnosos (p<0.05). Por otro, la comparación de los patrones de nacimientos en dos sitios muestra que donde la oferta de alimentos es estacional, los nacimientos se concentran en la época seca mientras que, donde la oferta de alimentos es continua, los nacimientos ocurren durante todo el año (p<0.01). La variación observada en los patrones de nacimientos y organización social, representaría una respuesta facultativa a cambios en disponibilidad de alimentos, que se traduce en una amplia plasticidad fenotípica para la especie. Esta plasticidad le conferiría ventajas para colonizar un nicho ecológico diverso. Estudios comparativos de este tipo, nos permiten develar patrones y principios validos que no pueden ser identificados solamente con el estudio de la especie humana.Asociación de Antropología Biológica de la República Argentina (AABRA

Relaciones entre el hábitat, demografía y organización social en monos aulladores negros

Los estudios de primates del Nuevo Mundo han sido escasamente abordados dentro de la antropología biológica, ya que no ocupan lugares importantes en estudios de evolución humana. Sin embargo, los estudios evolutivos, deberían incluir comparaciones entre primates para dilucidar principios generales aplicables a todo el Orden. Tras varios años de investigación sobre Alouatta caraya, en Argentina, se encontró que la organización social, la densidad y los patrones de nacimientos varían en ambientes con diferentes ofertas alimenticias. Por un lado, la comparación en cinco sitios diferentes mostró diferencias significativas en tamaño de grupo y densidad de primates que correlacionaron con la disponibilidad de especies con frutos carnosos (p<0.05). Por otro, la comparación de los patrones de nacimientos en dos sitios muestra que donde la oferta de alimentos es estacional, los nacimientos se concentran en la época seca mientras que, donde la oferta de alimentos es continua, los nacimientos ocurren durante todo el año (p<0.01). La variación observada en los patrones de nacimientos y organización social, representaría una respuesta facultativa a cambios en disponibilidad de alimentos, que se traduce en una amplia plasticidad fenotípica para la especie. Esta plasticidad le conferiría ventajas para colonizar un nicho ecológico diverso. Estudios comparativos de este tipo, nos permiten develar patrones y principios validos que no pueden ser identificados solamente con el estudio de la especie humana.Asociación de Antropología Biológica de la República Argentina (AABRA

CO\u3csub\u3e2\u3c/sub\u3e and tectonic controls on Antarctic climate and ice-sheet evolution in the mid-Miocene

Antarctic ice sheet and climate evolution during the mid-Miocene has direct relevance for understanding ice sheet (in)stability and the long-term response to elevated atmospheric CO2 in the future. Geologic records reconstruct major fluctuations in the volume and extent of marine and terrestrial ice during the mid-Miocene, revealing a dynamic Antarctic ice-sheet response to past climatic variations. We use an ensemble of climate – ice sheet – vegetation model simulations spanning a range of CO2 concentrations, Transantarctic Mountain uplift scenarios, and glacial/interglacial climatic conditions to identify climate and ice-sheet conditions consistent with Antarctic mid-Miocene terrestrial and marine geological records. We explore climatic variability at both continental and regional scales, focusing specifically on Victoria Land and Wilkes Land Basin regions using a high-resolution nested climate model over these domains. We find that peak warmth during the Miocene Climate Optimum is characterized by a thick terrestrial ice sheet receded from the coastline under high CO2 concentrations. During the Middle Miocene Climate Transition, CO2 episodically dropped below a threshold value for marine-based ice expansion. Comparison of model results with geologic data support ongoing Transantarctic Mountain uplift throughout the mid-Miocene. Modeled ice sheet dynamics over the Wilkes Land Basin were highly sensitive to CO2 concentrations. This work provides a continental-wide context for localized geologic paleoclimate and vegetation records, integrating multiple datasets to reconstruct snapshots of ice sheet and climatic conditions during a pivotal period in Earth\u27s history

Higher analogues of the discrete-time Toda equation and the quotient-difference algorithm

The discrete-time Toda equation arises as a universal equation for the relevant Hankel determinants associated with one-variable orthogonal polynomials through the mechanism of adjacency, which amounts to the inclusion of shifted weight functions in the orthogonality condition. In this paper we extend this mechanism to a new class of two-variable orthogonal polynomials where the variables are related via an elliptic curve. This leads to a `Higher order Analogue of the Discrete-time Toda' (HADT) equation for the associated Hankel determinants, together with its Lax pair, which is derived from the relevant recurrence relations for the orthogonal polynomials. In a similar way as the quotient-difference (QD) algorithm is related to the discrete-time Toda equation, a novel quotient-quotient-difference (QQD) scheme is presented for the HADT equation. We show that for both the HADT equation and the QQD scheme, there exists well-posed $s$-periodic initial value problems, for almost all \s\in\Z^2. From the Lax-pairs we furthermore derive invariants for corresponding reductions to dynamical mappings for some explicit examples.Comment: 38 page

¿Cuáles son los determinantes de los desplazamientos en monos aulladores negros y dorados?

Los patrones de uso del espacio en primates no-humanos son descriptos por el desplazamiento diario (DD) o la distancia media recorrida por día y por el área de acción. Existen factores sociales, así como también, factores ecológicos que influyen sobre los patrones de uso del espacio. Los sociales incluyen el tamaño de grupo, el número de grupos vecinos, la distancia entre individuos, y los ecológicos incluyen la distribución de los alimentos, la calidad del hábitat, el tiempo invertido en diferentes actividades y factores ambientales como temperatura media y precipitaciones, entre otros. Estos factores pueden explicar posibles diferencias en el DD entre grupos de primates. Se estudió la variación del DD en dos grupos vecinos (X y G) de Alouatta caraya de composición similar durante 12 meses en la Isla Brasilera, Chaco (27º 20' - 58º 40' W) y la asociación del mismo a diferentes variables. Para determinar qué factores pueden explicar la variación del DD, realizamos una regresión múltiple por pasos. Se utilizaron las siguientes variables independientes como predictores: el tiempo invertido en alimentación en hojas nuevas, hojas maduras, brotes, flores, frutos, la temperatura máxima diaria, la precipitación diaria, y el número diario de enfrentamientos con otros grupos, controlados por la variación estacional de la luz diaria. Para ambos grupos el mejor predictor fue la temperatura máxima diaria y para el Grupo X, el tiempo de alimentación sobre brotes y frutos también fue un predictor significativo del DD (Grupo X: F2,57=9.5, R2= 0.56, p<0.0005; Grupo G: F1,58=4.46, R2= 0.41, p<0.0005). El modelo explicó 56% de la varianza en el Grupo X y 45% en el Grupo G. En todos los casos, un incremento en el predictor resultó en un incremento del 30-50% del DD de los grupos. Posiblemente en los días más largos y de mayores temperaturas en el verano permitieron a los aulladores desplazarse más ya que incorporaban al menos una sesión más de alimentación durante el día. Por el contrario, el DD estuvo negativamente asociado con el descanso y con el desplazamiento en el Grupo X (Descanso: test de Spearman N=12, r=-0.61, p<0.05, desplazamiento: test de Spearman N=12, r=-0.85, p<0.001), lo cual indica que durante los meses de invierno los aulladores se desplazaban menos e invertían más tiempo en descanso. Generalmente, se espera que el tiempo invertido en desplazamiento sea menor a altas temperaturas. Los costos exactos o las restricciones debido a las variaciones de temperatura quedan todavía pendientes para explorar. Los primates no-humanos nos permiten no solo develar patrones comportamentales que no pueden ser identificados únicamente con el estudio de la especie humana, sino también enfoques comparativos útiles para elucidar principios generales aplicables a la interpretación de los comportamientos en nuestros ancestros.Asociación de Antropología Biológica de la República Argentin

Upwelling events, coastal offshore exchange, links to biogeochemical processes - Highlights from the Baltic Sea Sciences Congress at Rostock University, Germany, 19-22 March 2007

The Baltic Sea Science Congress was held at Rostock University, Germany, from 19 to 22 March 2007. In the session entitled"Upwelling events, coastal offshore exchange, links to biogeochemical processes" 20 presentations were given,including 7 talks and 13 posters related to the theme of the session.This paper summarises new findings of the upwelling-related studies reported in the session. It deals with investigationsbased on the use of in situ and remote sensing measurements as well as numerical modelling tools. The biogeochemicalimplications of upwelling are also discussed.Our knowledge of the fine structure and dynamic considerations of upwelling has increased in recent decades with the advent ofhigh-resolution modern measurement techniques and modelling studies. The forcing and the overall structure, duration and intensity ofupwelling events are understood quite well. However, the quantification of related transports and the contribution to the overall mixingof upwelling requires further research. Furthermore, our knowledge of the links between upwelling and biogeochemical processes is stillincomplete. Numerical modelling has advanced to the extent that horizontal resolutions of c. 0.5 nautical miles can now be applied,which allows the complete spectrum of meso-scale features to be described. Even the development of filaments can be describedrealistically in comparison with high-resolution satellite data.But the effect of upwelling at a basin scale and possible changes under changing climatic conditions remain open questions