A NEW SPECIES OF CHILOMYCTERUS FROM NEW GUINEA.

abstract not availabl

ON A COLLECYTION OF FRESHWATER FISHES OF THE ISLAND OF BILLITON

Abstract not availabl

Mobility of daughter elements of U-238 decay chain during leaching by In Situ Recovery (ISR) : New insights from digital autoradiography

In highly permeable sedimentary rock formations, U extraction by in-situ leaching techniques (ISR - In-Situ Recovery) is generally considered to have a limited environmental impact at ground level. Significantly, this method of extraction produces neither mill tailings nor waste rocks. Underground, however, the outcome for U-238 daughter elements in aquifers is not well known because of their trace concentrations in the host rocks. Thus, understanding the in-situ mobility of these elements remains a challenge. Two samples collected before and after six months of ISR experiments (Dulaan Uul, Mongolia) were studied with the help of a digital autoradiography technique (DA) of alpha particles, bulk alpha spectrometry, and complementary petrographic observation methods. These techniques demonstrate that before and after leaching, the radioactivity is concentrated in altered and microporous Fe-Ti oxides. Most of the daughter elements of U remain trapped in the rock after the leaching process. DA confirms that the alpha activity of the Fe-Ti oxides remains high after uranium leaching, and the initial secular equilibrium of the U-238 series for Th-230 to Po-210 daughter elements (including Ra-226) of the fresh rocks is maintained after leaching. While these findings should be confirmed by more systematic studies, they already identify potential mechanisms explaining why the U-daughter concentrations in leaching water are low.Peer reviewe

Influence of stoichiometry and structure on the optical properties of AlNxOy films

The AlNxOy system offers the possibility to obtain a wide range of responses, by tailoring the properties between Al, AlN and Al2O3, opening a significant number of possible applications. The aim of this work is to correlate the optical properties of AlNxOy thin films with their composition and structural features, taking as reference the binary systems AlNx and AlOy. In the AlNx system, the increase of the nitrogen content induced a wide variation in the optical properties, ranging from the typical profile of a polycrystalline Al-type film towards nearly constant reflectance values as low as 5%, as well as a smooth increase in samples transparency as the ratio N/Al approached unit. In the case of the AlOy system, the reflectance also decreased as the oxygen content increased, however the transition to transparent films (Al2O3-like) was more abrupt. The ternary system AlNxOy, revealed optical responses that ranged from a typical profile of a polycrystalline Al-type film, towards low and constant reflectance values in a wide range of x and y coefficients, ending up as semi-transparent when Al2O3-like films were formed. The unusual low optical reflectance of some films reveals some potential applications in solar power systems and sensors.This research is sponsored by FEDER funds through the program COMPETE-Programa Operacional Factores de Competitividade, by national funds through FCT,, under the projects PTDC/CTMNAN/ 112574/2009 and PEST-C-FIS/UI607/2011–2012, and Programa Pessoa 2010/2011—Cooperação Portugal/França, Proc. no 441.00, Project ‘COLOURCLUSTER’. J Borges also acknowledges FCT financial support under PhD grant no SFRH/BD/47118/200

Directional detection of meV dark photons with Dandelion

This paper presents Dandelion, a new dish antenna experiment searching for dark photons (DPs) with masses around the meV that will start acquiring data by the end of 2023. A spherical mirror acts as a conversion surface between DPs and standard photons that converge to a matrix of 418 Kinetic Inductance Detectors cooled down to 150 mK. A tilt of the mirror at 1 Hz moves the expected signal over the pixels thus enabling a continuous background measurement. The expected signal has two modulations: a spatial modulation providing a directional signature for the unambiguous discovery of a DP, and an intensity modulation allowing the determination of the polarization of the DP. For masses near the meV, the inflationary production of longitudinal and transverse DPs are mutually excluded, thus the polarization determination by Dandelion could shed a new light on the inflation phase of the early universe. A first Dandelion prototype operating for 30 days would improve by more than one order of magnitude the current exclusion limits on DPs at the meV mass scale and would probe this region with an unprecedented discovery potential based on directional detection.Comment: 17 pages, 7 figure

Dark Matter Directionality Detection performance of the Micromegas-based μ\muTPC-MIMAC detector

Directional Dark Matter Detection (DDMD) can open a new signature for Weakly Massive Interacting Particles (WIMPs) Dark Matter. The directional signature provides in addition, an unique way to overcome the neutron and neutrino backgrounds. In order to get the directional signature, the DDM detectors should be sensitive to low nuclear energy recoils in the keV range and have an angular resolution better than $20^{\circ}$. We have performed experiments with low energy ($<30\,\mathrm{keV}$) ion beam facilities to measure the angular distribution of nuclear recoil tracks in a MIMAC detector prototype. In this paper, we study angular spreads with respect to the electron drift direction ($0^{\circ}$ incident angle) of Fluorine nuclear tracks in this low energy range, and show nuclear recoil angle reconstruction produced by a monoenergetic neutron field experiment. We find that a high-gain systematic effect leads to a high angular resolution along the electron drift direction. The measured angular distribution is impacted by diffusion, and space charge or ion feedback effects, which can be corrected for by an asymmetry factor observed in the flash-ADC profile. The estimated angular resolution of the $0^{\circ}$ incident ion is better than $15^{\circ}$ at $10$ keV kinetic energy and agrees with the simulations within $20$%. The distributions from the nuclear recoils have been compared with simulated results based on a modified Garfield++ code. Our study shows that protons would be a more adapted target than heavier nuclei for DDMD of light WIMPs. We demonstrate that directional signature from the Galactic halo origin of a Dark Matter WIMP signal is experimentally achievable, with a deep understanding of the operating conditions of a low pressure detector with its diffusion mechanism.Comment: 19 pages, 12 figure

Electrical properties of AlNxOy thin films prepared by reactive magnetron sputtering

Direct current magnetron sputtering was used to produce AlNxOy thin films, using an aluminum target, argon and a mixture of N2+O2 (17:3) as reactive gases. The partial pressure of the reactive gas mixture was increased, maintaining the discharge current constant. Within the two identified regimes of the target (metallic and compound), four different tendencies for the deposition rate were found and a morphological evolution from columnar towards cauliflower-type, ending up as dense and featureless-type films. The structure was found to be Al-type (face centered cubic) and the structural characterization carried out by X-ray 2 diffraction and transmission electron microscopy suggested the formation of an aluminumbased polycrystalline phase dispersed in an amorphous aluminum oxide/nitride (or oxynitride) matrix. This type of structure, composition, morphology and grain size, were found to be strongly correlated with the electrical response of the films, which showed a gradual transition between metallic-like responses towards semiconducting and even insulating-type behaviors. A group of films with high aluminum content revealed a sharp decrease of the temperature coefficient of resistance (TCR) as the concentration ratio of non-metallic/aluminum atomic ratio increased. Another group of samples, where the non-metallic content became more important, revealed a smooth transition between positive and negative values of TCR. In order to test whether the oxynitride films have a unique behavior or simply a transition between the typical responses of aluminum and of those of the correspondent nitride and oxide, the electrical properties of the ternary oxynitride system were compared with AlNx and AlOy systems, prepared in similar conditions.This research is sponsored by FEDER funds through the program COMPETE-Programa Operacional Factores de Competitividade, by the national funds through FCT-Fundação para a Ciência e a Tecnologia, under the project PTDC/CTM-NAN/112574/2009 and Programa Pessoa 2010/2011 Cooperação Portugal/França, Proc.º 441.00, Project“COLOURCLUSTER”. J. Borges also acknowledges FCT financial support under PhD grant no. SFRH/BD/47118/2008

Proteomic profiling in cerebral amyloid angiopathy reveals an overlap with CADASIL highlighting accumulation of HTRA1 and its substrates

Cerebral amyloid angiopathy (CAA) is an age-related condition and a major cause of intracerebral hemorrhage and cognitive decline that shows close links with Alzheimer's disease (AD). CAA is characterized by the aggregation of amyloid-β (Aβ) peptides and formation of Aβ deposits in the brain vasculature resulting in a disruption of the angioarchitecture. Capillaries are a critical site of Aβ pathology in CAA type 1 and become dysfunctional during disease progression. Here, applying an advanced protocol for the isolation of parenchymal microvessels from post-mortem brain tissue combined with liquid chromatography tandem mass spectrometry (LC-MS/MS), we determined the proteomes of CAA type 1 cases (n = 12) including a patient with hereditary cerebral hemorrhage with amyloidosis-Dutch type (HCHWA-D), and of AD cases without microvascular amyloid pathology (n = 13) in comparison to neurologically healthy controls (n = 12). ELISA measurements revealed microvascular Aβ1-40 levels to be exclusively enriched in CAA samples (mean: > 3000-fold compared to controls). The proteomic profile of CAA type 1 was characterized by massive enrichment of multiple predominantly secreted proteins and showed significant overlap with the recently reported brain microvascular proteome of patients with cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a hereditary cerebral small vessel disease (SVD) characterized by the aggregation of the Notch3 extracellular domain. We found this overlap to be largely attributable to the accumulation of high-temperature requirement protein A1 (HTRA1), a serine protease with an established role in the brain vasculature, and several of its substrates. Notably, this signature was not present in AD cases. We further show that HTRA1 co-localizes with Aβ deposits in brain capillaries from CAA type 1 patients indicating a pathologic recruitment process. Together, these findings suggest a central role of HTRA1-dependent protein homeostasis in the CAA microvasculature and a molecular connection between multiple types of brain microvascular disease