2,000 research outputs found
Conductive structures around Las Cañadas caldera, Tenerife (Canary Islands, Spain) : a structural control
External eastern areas of the Las Cañadas caldera (LCC) of Tenerife (Canary Islands, Spain) have been investigated using the audiomagnetotelluric (AMT) method with the aim to characterize the physical rock properties at shallow depth and the thickness of a first resistive layer. Using the results of 50 AMT tensors carried out in the period range of 0.001 s to 0.3 s, this study provides six unpublished AMT profiles distributed in the upper Orotava valley and data from the Pedro Gil caldera (Dorsal Ridge). Showing obvious 1-D behaviour, soundings have been processed through 1-D modeling and gathered to form profiles. Underlying a resistive cover (150-2000 Om), a conductive layer at shallow depth (18-140 Om, 250-1100 m b.g.l.) which is characterized by a "wavy-like" structure, often parallel to the topography, appears in all profiles. This paper points out the ubiquitous existence in Tenerife of such a conductive layer, which is the consequence of two different processes: a) according to geological data, the enhanced conductivity of the flanks is interpreted as a plastic breccia within a clayish matrix generated during huge lateral collapse; and b) along main tectonic structures and inside calderas, this layer is formed by hidrotermal alteration processes. In both areas, the conductive layer is thought to be related to major structural volcanic events (flank or caldera collapse) and can be seen as a temporal marker of the island evolution. Moreover, its slope suggests possible headwall locations of the giant landslides that affected the flanks of Tenerife
Cytoadhesion of Plasmodium falciparum-infected erythrocytes and the infected placenta: a two-way pathway
Malaria is undoubtedly the world's most devastating parasitic disease, affecting 300 to 500 million people every year. Some cases of Plasmodium falciparum infection progress to the deadly forms of the disease responsible for 1 to 3 million deaths annually. P. falciparum-infected erythrocytes adhere to host receptors in the deep microvasculature of several organs. The cytoadhesion of infected erythrocytes to placental syncytiotrophoblast receptors leads to pregnancy-associated malaria (PAM). This specific maternal-fetal syndrome causes maternal anemia, low birth weight and the death of 62,000 to 363,000 infants per year in sub-Saharan Africa, and thus has a poor outcome for both mother and fetus. However, PAM and non-PAM parasites have been shown to differ antigenically and genetically. After multiple pregnancies, women from different geographical areas develop adhesion-blocking antibodies that protect against placental parasitemia and clinical symptoms of PAM. The recent description of a new parasite ligand encoded by the var2CSA gene as the only gene up-regulated in PAM parasites renders the development of an anti-PAM vaccine more feasible. The search for a vaccine to prevent P. falciparum sequestration in the placenta by eliciting adhesion-blocking antibodies and a cellular immune response, and the development of new methods for evaluating such antibodies should be key priorities in mother-child health programs in areas of endemic malaria. This review summarizes the main molecular, immunological and physiopathological aspects of PAM, including findings related to new targets in the P. falciparum var gene family. Finally, we focus on a new methodology for mimicking cytoadhesion under blood flow conditions in human placental tissue.1525153
Cytoadhesion of Plasmodium falciparum-infected erythrocytes and the infected placenta: a two-way pathway
This find is registered at Portable Antiquities of the Netherlands with number PAN-0005548
Cytoadhesion of Plasmodium falciparum-infected erythrocytes and the infected placenta: a two-way pathway
Reactions from family of origin to the disclosure of lesbian motherhood via donor insemination
Most studies of planned lesbian motherhood via donor insemination (DI) have sampled lesbian mothers in individualistic societies where adults have relatively distant connection to their family of origin. Our study examined the experiences of biological and non-biological lesbian mothers in five families who had children through DI after disclosing their motherhood status to their family networks in Portugal, a familistic society. The first theme identified by thematic analysis, âBut why do you want to have a child?â encapsulated the reactions of biological mothersâ family of origin to the announcement of motherhood. Disclosure was mostly met by a shocked response in the extended family, rooted in the belief that lesbian women should not have children. The second theme, âBut you werenât pregnant, how is this your child?â summarized the reactions of non-biological mothersâ family of origin to the disclosure of motherhood status as they considered refusing to recognize their grandchild in the absence of biological connection. Prejudice against lesbian-mother family formation was associated with the specific intersection of lesbianism and motherhood, but relationships between the mothers and their families were largely repaired because of familistic values
On the statistical significance of the conductance quantization
Recent experiments on atomic-scale metallic contacts have shown that the
quantization of the conductance appears clearly only after the average of the
experimental results. Motivated by these results we have analyzed a simplified
model system in which a narrow neck is randomly coupled to wide ideal leads,
both in absence and presence of time reversal invariance. Based on Random
Matrix Theory we study analytically the probability distribution for the
conductance of such system. As the width of the leads increases the
distribution for the conductance becomes sharply peaked close to an integer
multiple of the quantum of conductance. Our results suggest a possible
statistical origin of conductance quantization in atomic-scale metallic
contacts.Comment: 4 pages, Tex and 3 figures. To be published in PR
Intentional kinship through caring relationships, heritage, and identity: adoptive parentsâ inclusion of non-biological and non-affinal relationships on family maps
Structural open adoption has been beneficial to adoptees in integrating their birth heritage and identity. Adoptive parents also may sometimes seek out others who are neither related biologically nor through partnership to support their child in developing an integrated sense of identity. To what extent do these intentional kinship relationships become incorporated within the adoptive family network and how do adoptive parents view their role in their childâs life? Qualitative data on family inclusion of non-biological and non-affinal kin are reported from interviews with lesbian, gay, bisexual, and heterosexual adoptive parents (n = 25 families). Analyses of verbal and visual data from family map drawing interviews indicated that adoptive parents from the different types of families similarly included intentional kin in their conceptualization of their childâs family. Adopted childrenâs foster carers, family friends, other adoptive families, and other children and adults were specifically included on family maps to facilitate childrenâs knowledge of different aspects of their birth heritage and adoption story. The implications of open adoption policy therefore move beyond considerations of only birth family contact. In practice, open adoption procedures convey a broad message to families that appear to widen adoptive parentsâ conceptualization of kinship
A Comparative Study of the Formation of Aromatics in Rich Methane Flames Doped by Unsaturated Compounds
For a better modeling of the importance of the different channels leading to
the first aromatic ring, we have compared the structures of laminar rich
premixed methane flames doped with several unsaturated hydrocarbons: allene and
propyne, because they are precursors of propargyl radicals which are well known
as having an important role in forming benzene, 1,3-butadiene to put in
evidence a possible production of benzene due to reactions of C4 compounds,
and, finally, cyclopentene which is a source of cyclopentadienylmethylene
radicals which in turn are expected to easily isomerizes to give benzene. These
flames have been stabilized on a burner at a pressure of 6.7 kPa (50 Torr)
using argon as dilutant, for equivalence ratios (?) from 1.55 to 1.79. A unique
mechanism, including the formation and decomposition of benzene and toluene,
has been used to model the oxidation of allene, propyne, 1,3 butadiene and
cyclopentene. The main reaction pathways of aromatics formation have been
derived from reaction rate and sensitivity analyses and have been compared for
the three types of additives. These combined analyses and comparisons can only
been performed when a unique mechanism is available for all the studied
additives
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