The Cognitive Thalamus as a gateway to mental representations

Historically, the thalamus has been viewed as little more than a relay, simply transferring information to key players of the cast, the cortex and hippocampus, without providing any unique functional contribution. In recent years, evidence from multiple laboratories researching different thalamic nuclei has contradicted this idea of the thalamus as a passive structure. Dated models of thalamic functions are being pushed aside, revealing a greater and far more complex contribution of the thalamus for cognition. In this Viewpoint, we show how recent data support novel views of thalamic functions that emphasize integrative roles in cognition, ranging from learning and memory to flexible adaption. We propose that these apparently separate cognitive functions may, in fact, be supported by a more general role in shaping mental representations. Several features of thalamocortical circuits are consistent with this suggested role and we highlight how divergent and convergent thalamocortical and corticothalamic pathways may complement each other to support these functions. Furthermore, the role of the thalamus for subcortical integration is highlighted as a key mechanism for maintaining and updating representations. Finally, we discuss future areas of research and stress the importance of incorporating new experimental findings into existing knowledge to continue developing thalamic models. The presence of thalamic pathology in a number of neurological conditions reinforces the need to better understand the role of this region in cognition

Cartographie de la croissance urbaine de Kinshasa (R.D. Congo) entre 1995 et 2005 par télédétection satellitaire à haute résolution

La croissance spatiale de Kinshasa (RDC) est cartographiée par classification des espaces bâtis au départ d’images satellitaires SPOT datant de 1995 et 2005. D’après les résultats, la croissance de la ville est moins rapide que l’évolution démographique ; elle s’effectue désormais dans les espaces interstitiels en dépit de leurs fortes pentes et d’un certain éloignement des principales voies de communication (au delà d’1 km).The urban growth of Kinshasa (DRC) is mapped by classification of built-up areas using SPOT images dating from 1995 and 2005. From the results, the city growth is slower than the population growth; it is taking place within interstitial areas despite their steep slopes and their distance (1 km) from the main communication axes

The role of diatom resting spores for pelagic-benthic coupling in the Southern Ocean

Abstract. Natural iron fertilization downstream of Southern Ocean island plateaus support large phytoplankton blooms and promote carbon export from the mixed layer. In addition to sequestering atmospheric CO2, the biological carbon pump also supplies organic matter (OM) to deep-ocean ecosystems. Although the total flux of OM arriving at the seafloor sets the energy input to the system, the chemical nature of OM is also of significance. However, a quantitative framework linking ecological flux vectors to OM composition is currently lacking. In the present study we report the lipid composition of export fluxes collected by five-moored sediment traps deployed in contrasting productivity regimes of Southern Ocean island systems (Kerguelen, Crozet and South Georgia) and compile them with quantitative data on diatom and fecal pellet fluxes. At the three naturally iron fertilized sites, the relative contribution of labile lipids (mono- and polyunsaturated fatty acids, unsaturated fatty alcohols) is 2–4 times higher than at low productivity sites. There is a strong attenuation of labile components as a function of depth, irrespective of productivity. The three island systems also display regional characteristics in lipid export. The diversity of sterols is greater in the relatively warm waters of the Polar Frontal Zone when compared to the Antarctic zone, reflecting the transition from mixed phytoplankton communities to principally diatom-derived OM. An enrichment of zooplankton dietary sterols, such as C27Δ5, at South Georgia is consistent with high zooplankton and krill biomass in the region and the importance of fecal pellets to POC flux. There is a strong association of diatom resting spore fluxes that dominate productive flux regimes with energy rich unsaturated fatty acids. At the Kerguelen Plateau we provide a statistical framework to link seasonal variation in ecological flux vectors and lipid composition over a complete annual cycle. Our analyses demonstrate that ecological processes in the upper ocean, e.g. resting spore formation and grazing, not only impact the magnitude and stoichiometry of the Southern Ocean biological pump, but also regulate the composition of exported OM and the nature of pelagic-benthic coupling. </jats:p

Determination of the emission rates of CO2 point sources with airborne lidar

We report on CO2 emissions of a coal-fired power plant derived from flight measurements performed with the IPDA lidar CHARM-F during the CoMet campaign in spring 2018. Despite the results being in broad agreement with reported emissions, we observe strong variations between successive flyovers. Using a high-resolution large eddy simulation, we identify strong atmospheric turbulence as the cause for the variations and recommend more favorable measurement conditions for future campaign planning

HAGE (DDX43) is a biomarker for poor prognosis and a predictor of chemotherapy response in breast cancer

Background: HAGE protein is a known immunogenic cancer-specific antigen. Methods: The biological, prognostic and predictive values of HAGE expression was studied using immunohistochemistry in three cohorts of patients with BC (n=2147): early primary (EP-BC; n=1676); primary oestrogen receptor-negative (PER-BC; n=275) treated with adjuvant anthracycline-combination therapies (Adjuvant-ACT); and primary locally advanced disease (PLA-BC) who received neo-adjuvant anthracycline-combination therapies (Neo-adjuvant-ACT; n=196). The relationship between HAGE expression and the tumour-infiltrating lymphocytes (TILs) in matched prechemotherapy and postchemotherapy samples were investigated. Results: Eight percent of patients with EP-BC exhibited high HAGE expression (HAGEþ) and was associated with aggressive clinico-pathological features (Ps<0.01). Furthermore, HAGEþexpression was associated with poor prognosis in both univariate and multivariate analysis (Ps<0.001). Patients with HAGE+ did not benefit from hormonal therapy in high-risk ER-positive disease. HAGE+ and TILs were found to be independent predictors for pathological complete response to neoadjuvant-ACT; P<0.001. A statistically significant loss of HAGE expression following neoadjuvant-ACT was found (P=0.000001), and progression-free survival was worse in those patients who had HAGE+ residual disease (P=0.0003). Conclusions: This is the first report to show HAGE to be a potential prognostic marker and a predictor of response to ACT in patients with BC

Rotational velocities of nearby young stars

Stellar rotation is a crucial parameter driving stellar magnetism, activity and mixing of chemical elements. Furthermore, the evolution of stellar rotation is coupled to the evolution of circumstellar disks. Disk-braking mechanisms are believed to be responsible for rotational deceleration during the accretion phase, and rotational spin-up during the contraction phase after decoupling from the disk for fast rotators arriving at the ZAMS. We investigate the projected rotational velocities vsini of a sample of young stars with respect to the stellar mass and disk evolutionary state to search for possible indications of disk-braking mechanisms. We analyse the stellar spectra of 220 nearby (mostly <100pc) young (2-600 Myr) stars for their vsini, stellar age, Halpha emission, and accretion rates. The stars have been observed with FEROS and HARPS in La Silla, Chile. The spectra have been cross-correlated with appropriate theoretical templates. We build a new calibration to be able to derive vsini values from the cross-correlated spectra. Stellar ages are estimated from the LiI equivalent width at 6708 Ang. The equivalent width and width at 10% height of the Halpha emission are measured to identify accretors and used to estimate accretion rates. The vsini is then analysed with respect to the evolutionary state of the circumstellar disks to search for indications of disk-braking mechanisms in accretors. We find that the broad vsini distribution of our targets extends to rotation velocities of up to more than 100 km/s and peaks at a value of 7.8+-1.2 km/s, and that ~70% of our stars show vsini<30 km/s. Furthermore, we can find indications for disk-braking in accretors and rotational spin-up of stars which are decoupled from their disks. In addition, we show that a number of young stars are suitable for precise radial-velocity measurements for planet-search surveys.Comment: 16 pages, 6 figures, accepted for publication in A&

Amphiphilic block copolymers enhance the cellular uptake of DNA molecules through a facilitated plasma membrane transport

Amphiphilic block copolymers have been developed recently for their efficient, in vivo transfection activities in various tissues. Surprisingly, we observed that amphiphilic block copolymers such as Lutrol® do not allow the transfection of cultured cells in vitro, suggesting that the cell environment is strongly involved in their mechanism of action. In an in vitro model mimicking the in vivo situation we showed that pre-treatment of cells with Lutrol®, prior to their incubation with DNA molecules in the presence of cationic lipid, resulted in higher levels of reporter gene expression. We also showed that this improvement in transfection efficiency associated with the presence of Lutrol® was observed irrespective of the plasmid promoter. Considering the various steps that could be improved by Lutrol®, we concluded that the nucleic acids molecule internalization step is the most important barrier affected by Lutrol®. Microscopic examination of transfected cells pre-treated with Lutrol® confirmed that more plasmid DNA copies were internalized. Absence of cationic lipid did not impair Lutrol®-mediated DNA internalization, but critically impaired endosomal escape. Our results strongly suggest that in vivo, Lutrol® improves transfection by a physicochemical mechanism, leading to cellular uptake enhancement through a direct delivery into the cytoplasm, and not via endosomal pathways

Yearly and seasonal variations of low albedo surfaces on Mars in the OMEGA/MEx dataset: Constraints on aerosols properties and dust deposits

The time variations of spectral properties of dark martian surface features are investigated using the OMEGA near-IR dataset. The analyzed period covers two Mars years, spanning from early 2004 to early 2008 (includes the 2007 global dust event). Radiative transfer modeling indicates that the apparent albedo variations of low to mid-latitude dark regions are consistent with those produced by the varying optical depth of atmospheric dust as measured simultaneously from the ground by the Mars Exploration Rovers. We observe only a few significant albedo changes that can be attributed to surface phenomena. They are small-scaled and located at the boundaries between bright and dark regions. We then investigate the variations of the mean particle size of aerosols using the evolution of the observed dark region spectra between 1 and 2.5 {\mu}m. Overall, we find that the observed changes in the spectral slope are consistent with a mean particle size of aerosols varying with time between 1 and 2 {\mu}m. Observations with different solar zenith angles make it possible to characterize the aerosol layer at different altitudes, revealing a decrease of the particle size of aerosols as altitude increases

Chirality scenario of the spin-glass ordering

Detailed account is given of the chirality scenario of experimental spin-glass transitions. In this scenario, the spin glass order of weakly anisotropic Heisenberg-like spin-glass magnets including canonical spin glasses are essentially chirality driven. Recent numerical and experimental results are discussed in conjunction with this scenario.Comment: Submitted to J. Phys. Soc. Japan "Special Issue on Frustration