Storage and discharge of a granular fluid

Experiments and computational simulations are carried out to study the behavior of a granular column in a silo whose walls are able to vibrate horizontally. The column is brought to a steady fluidized state and it behaves similar to a hydrostatic system. We study the dynamics of the granular discharge through openings at the bottom of the silo in order to search for a Torricelli-like behavior. We show that the flow rate scales with the wall induced shear rate, and at high rates, the granular bed indeed discharges similar to a viscous fluid

First bird footprints from the lower Miocene Lerín Formation, Ebro Basin, Spain

A new tracksite with bird footprints, found in the Bardenas Reales de Navarra Natural Park (Navarre, Spain), is presented in this study. The footprints are preserved in four sandstone blocks of the Lerín Formation from the northwest sector of the Ebro Basin. According to the magnetostratigraphic data, the age of these blocks is 20.4 Ma (Agenian, lower Miocene). The footprints are more than 100 mm in length, mesaxonic, and tridactyl, and have a prominent central pad impression with the digit impressions not jointed proximally. These features allow classifying them as Uvaichnites riojana. Some of the studied footprints are better preserved than the type series of Uvaichnites, which were found also in the northwest sector of the Ebro Basin. Therefore, the original diagnosis has been emended. Available chronostratigraphic data for these localities as well as for other footprints from China indicate a latest Oligocene-earliest Miocene age (from about 23 to 20 Ma) for Uvaichnites-like footprints. Sedimentological data also indicate similar continental environments, namely perilacustrine deltaic systems and distal alluvial systems. The information about early Miocene avian remains (bones, eggs and footprints) in the Iberian Peninsula is scarce. The skeletal and oological record of this age has been included within the families Phoenicopteridae, Phaisanidae and Cathartidae (or incertae sedis), while the ichnological record was related with trackmakers belonging to Charadriiformes, Ardeidae and Gruidae taxa. For this scenario, in which there are few avian remains, the ichnological diversity shown in this paper complements and improves the knowledge about the Iberian avian diversity in the early Miocene

Descolonizando Tiempo, Espacio y Conocimiento: El pueblo Kamëntšá en la encrucijada del patrimonio cultural

The dissertation is focused on three interrelated aspects: 1) the development of a decolonial theoretical framework and collaborative research methodology with the Kamëntšá people centred on the respect for Kamëntšá ethics, principles and social norms, and the consequent reconstruction, revitalization and dignification of Kamëntšá knowledge, arts, spirituality and notions of time and space; 2) the history and colonization processes of the Kamëntšá people and Uaman Tabanok, its ancestral lands, with a specific emphasis on the work of the Capuchin missionaries, particularly their concept of enculturation and how it transformed and resignified Kamëntšá culture and religion using its own arts, narratives and rituals which were in harmony with Christianity; and 3) the concept of “cultural heritage” and the role of academic disciplines, research practices, government institutions and cultural policies in the perpetuation of colonialism through the appropriation, interpretation, control and resignification of the objects, monuments and cultures of Indigenous peoples, and their consequent contribution to maintaining inequality, racism and historical social injustices.Gerda Henkel Foundation Portuguese Foundation for Science and Technology (FCT) German Academic Exchange Service (DAAD) COLING Project - EU Horizon 2020 program under the Marie Skłodowska-Curie Grant Agreement No 778384Heritage of Indigenous People

Phenotypic Characteristics and Copy Number Variants in a Cohort of Colombian Patients with VACTERL Association

VACTERL association (OMIM 192350) is a heterogeneous clinical condition characterized by congenital structural defects that include at least 3 of the following features: vertebral abnormalities, anal atresia, heart defects, tracheoesophageal fistula, renal malformations, and limb defects. The nonrandom occurrence of these malformations and some familial cases suggest a possible association with genetic factors such as chromosomal alterations, gene mutations, and inherited syndromes such as Fanconi anemia (FA). In this study, the clinical phenotype and its relationship with the presence of chromosomal abnormalities and FA were evaluated in 18 patients with VACTERL association. For this, a G-banded karyotype, array-comparative genomic hybridization, and chromosomal fragility test for FA were performed. All patients (10 female and 8 male) showed a broad clinical spectrum: 13 (72.2%) had vertebral abnormalities, 8 (44.4%) had anal atresia, 14 (77.8%) had heart defects, 8 (44.4%) had esophageal atresia, 10 (55.6%) had renal abnormalities, and 10 (55.6%) had limb defects. Chromosomal abnormalities and FA were ruled out. In 2 cases, the finding of microalterations, namely del(15)(q11.2) and dup(17)(q12), explained the phenotype; in 8 cases, copy number variations were classified as variants of unknown significance and as not yet described in VACTERL. These variants comprise genes related to important cellular functions and embryonic development

Variations in water use by a mature mangrove of Avicennia germinans, French Guiana

In the tropical intertidal zones, little is known on water uptake by mangroves. Transpiration rates are generally measured at leaf level, but few studies exist on water use at tree or stand levels. The objective of this study was to measure sap flow in trees of different sizes to appreciate the range of variation in water use that may exist in a site dominated by 80% mature Avicennia germinans. The results showed that from the dry to the wet season the mean water use increased from 3.2 to 5.3 dm3 d−1 in small trees (DBH ∼ 13 cm), from 11.5 to 30.8 dm3 d−1 in medium trees (∼24 cm) and from 40.8 to 64.1 dm3 d−1 in large ones (∼45 cm). Sapwood remained active up to a depth of 8 cm with radial variations within the stem. Weak correlations were obtained with VPD and net radiation. This study confirmed that transpiration was larger under low levels of salinity. Water use at stand level (∼1900 living stems ha−1) was estimated to be in the range of 5.8 to 11.8 m3 ha−1 d−1 according to the season

Functional characterization of a melon alcohol acyl-transferase gene family involved in the biosynthesis of ester volatiles. Identification of the crucial role of a threonine residue for enzyme activity

Volatile esters, a major class of compounds contributing to the aroma of many fruit, are synthesized by alcohol acyl-transferases (AAT). We demonstrate here that, in Charentais melon (Cucumis melo var. cantalupensis), AAT are encoded by a gene family of at least four members with amino acid identity ranging from 84% (Cm-AAT1/Cm-AAT2) and 58% (Cm-AAT1/Cm-AAT3) to only 22% (Cm-AAT1/Cm-AAT4). All encoded proteins, except Cm-AAT2, were enzymatically active upon expression in yeast and show differential substrate preferences. Cm-AAT1 protein produces a wide range of short and long-chain acyl esters but has strong preference for the formation of E-2-hexenyl acetate and hexyl hexanoate. Cm-AAT3 also accepts a wide range of substrates but with very strong preference for producing benzyl acetate. Cm-AAT4 is almost exclusively devoted to the formation of acetates, with strong preference for cinnamoyl acetate. Site directed mutagenesis demonstrated that the failure of Cm-AAT2 to produce volatile esters is related to the presence of a 268-alanine residue instead of threonine as in all active AAT proteins. Mutating 268-A into 268-T of Cm-AAT2 restored enzyme activity, while mutating 268-T into 268-A abolished activity of Cm-AAT1. Activities of all three proteins measured with the prefered substrates sharply increase during fruit ripening. The expression of all Cm-AAT genes is up-regulated during ripening and inhibited in antisense ACC oxidase melons and in fruit treated with the ethylene antagonist 1-methylcyclopropene (1-MCP), indicating a positive regulation by ethylene. The data presented in this work suggest that the multiplicity of AAT genes accounts for the great diversity of esters formed in melon

Measurements of 12C(→γ,pp) photon asymmetries for Eγ= 200–450 MeV

The 12C (→γ ,pp) reaction has been studied in the photon energy range 200-450 MeV at the Mainz microtron MAMI-C, where linearly polarised photons were energy-tagged using the Glasgow-Mainz Tagged Photon Spectrometer and protons were detected in the Crystal Ball detector. The photon asymmetry Σ has been measured over a wider Eγ range than previous measurements. The strongest asymmetries were found at low missing energies where direct emission of nucleon pairs is expected. Cuts on the difference in azimuthal angles of the two ejected protons increased the magnitude of the observed asymmetries. At low missing energies the Σ data exhibit a strong angular dependence, similar to deuteron photodisintegration

Loans, logins and lasting the course: Academic library use and student retention

Activities and services that improve student engagement and retention in the higher education sector are important not only to individual student’s success but also to university planning and funding. This paper reports on a quantitative study that was carried out to explore whether use of the library by new university students is associated with continued enrolment. Students’ socioeconomic background and age were also examined in relation to library use. Limited to commencing students in March 2010 at Curtin University, the study drew on demographic data from the University’s enrolment system and instances of library use from the Library’s management system. Results of the statistical analyses indicate that library use is associated with retention, and importantly, library use in the early weeks of a student’s first semester is associated with retention. ‘Mature aged’ (21 years and over) students displayed different library use patterns than their younger colleagues and there was some variation in library use between students from different socioeconomic backgrounds. Findings from this study suggest that academic libraries can contribute to the retention of students and that carefully targeted programs and services may improve library use by some groups of students

Molecular Dynamics for Fermions

The time-dependent variational principle for many-body trial states is used to discuss the relation between the approaches of different molecular dynamics models to describe indistinguishable fermions. Early attempts to include effects of the Pauli principle by means of nonlocal potentials as well as more recent models which work with antisymmetrized many-body states are reviewed under these premises. Keywords: Many-body theory; Fermion system; Molecular dynamics; Wave-packet dynamics; Time-dependent variational principle; Statistical properties; Canonical ensemble; Ergodicity; Time averagingComment: 97 pages, 13 postscript figures. To be published in July 2000 issue of Reviews of Modern Physics. More information at http://www-aix.gsi.de/~fmd

Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory

Data from the Pierre Auger Observatory are analyzed to search for anisotropies near the direction of the Galactic Centre at EeV energies. The exposure of the surface array in this part of the sky is already significantly larger than that of the fore-runner experiments. Our results do not support previous findings of localized excesses in the AGASA and SUGAR data. We set an upper bound on a point-like flux of cosmic rays arriving from the Galactic Centre which excludes several scenarios predicting sources of EeV neutrons from Sagittarius $A$. Also the events detected simultaneously by the surface and fluorescence detectors (the `hybrid' data set), which have better pointing accuracy but are less numerous than those of the surface array alone, do not show any significant localized excess from this direction.Comment: Matches published versio