99 research outputs found

    STUDIO ETNOARCHEOMETRICO DI MALTE AEREE A LEGANTE GESSOSO NELL’AREA DELLE MADONIE (SICILIA SETTENTRIONALE)

    Get PDF
    The Madonie Regional Park, which covers an area of about 400 square kilometres, is an ideal context where environment and man activities are still mixed harmoniously. In the last years a variety of ethno-archaeometric investigations have been carried out in order to study various aspects of the "material culture" of this territory. In particular, the research was focused on the production of majolica which have had a great importance since the early decades of the 16th century thanks to the geolithological features of the Madonie area, particularly rich in clayey raw material. The traditional building techniques of the Madonie which involve several typologies of building materials (used for ordinary masonry, decorative elements, in the manufacture of artificial aggregates) were also influenced by the geological characteristics of the territory. In this direction, several studies have been recently organized in order to identify the ancient sources of raw materials and the reconstruction of the so-called "productive chain". The present contribution is aimed to the characterization of gypsum-based mortars locally made and widely employed on building tradition of the Madonie area. These were made using gypsum as raw material extracted in the same area and fired in special furnaces that today are testified only by few ruins. The examined samples are representative of gypsum mortars used on local stone-built structure. The study, enriched by documentary/ethnographic research on traditional kilns, locally called "carcare", was conducted by means of mineralogical and petrographic methods (XRD, optical microscopy and SEM-EDS) with the aim to characterize historic mortars in terms of composition and texture and recover the ancient recipes and also localize the source area of raw materials. The data obtained will be useful for planning the restoration (integration or replacement) of historic buildings in the area

    Archaeometric evidence attesting production of indigenous archaic pottery at Monte Polizzo (Western Sicily)

    Get PDF
    Excavations at the proto-urban indigenous settlement of Monte Polizzo (western Sicily) have not yielded so far any evidence of in-situ ceramic production (i.e. kiln structures). However several archaeological concerns put forward to consider it as a likely production centre of pottery during the Archaic age. In this paper a first attempt to check the compositional correspondence between ceramic fabrics and local clay sources has been made. A comprehensive archaeometric investigation of native pottery, mainly composed of matte-painted table ware dated from the 7th to the 4th century BC, recovered from the Acropolis of Monte Polizzo has allowed the identification of five distinct ‘Paste Compositional Reference Units’ (PCRUs). The five PCRUs were independently identified and confirmed through textural and mineralogical characteristics (petrographic observations) and chemical characterization (XRF analysis). A parallel investigation of clayey raw material of Monte Polizzo’s natural resources revealed two geologic formations the Terravecchia and Marnoso-Arenacea del Belice (MAB). Experimental ceramic briquettes were created and mineralogically and petrographically characterized. A comparison between the native and experimental ceramics revealed that the native ceramists preferred clays from the Terravecchia Formation. The mineralogical, textural and chemical composition of the raw clays of the Terravecchia Formation resulted to be well correlated with the 92% of the native ceramic artefacts recovered from Monte Polizzo. The remaining 8% are interpreted to be imported from the Sicani Mounts area

    Population-Level Benefits from Providing Effective HIV Prevention Means to Pregnant Women in High Prevalence Settings

    Get PDF
    Background:HIV prevalence among pregnant women in Southern Africa is extremely high. Epidemiological studies suggest that pregnancy increases the risk of HIV sexual acquisition and that HIV infections acquired during pregnancy carry higher risk of mother-to-child transmission (MTCT). We analyze the potential benefits from extending the availability of effective microbicide to pregnant women (in addition to non-pregnant women) in a wide-scale intervention.Methods and Findings:A transmission dynamic model was designed to assess the impact of microbicide use in high HIV prevalence settings and to estimate proportions of new HIV infections, infections acquired during pregnancy, and MTCT prevented over 10 years. Our analysis suggests that consistent use of microbicide with 70% efficacy by 60% of non-pregnant women may prevent approximately 40% and 15% of new infections in women and men respectively over 10 years, assuming no additional increase in HIV risk to either partner during pregnancy (RRHIV/preg = 1). It may also prevent 8-15% MTCT depending on the increase in MTCT risk when HIV is acquired during pregnancy compared to before pregnancy (RRMTCT/preg). Extending the microbicides use during pregnancy may improve the effectiveness of the intervention by 10% (RRHIV/preg = 1) to 25% (RRHIV/preg = 2) and reduce the number of HIV infections acquired during pregnancy by 40% to 70% in different scenarios. It may add between 6% (RRHIV/preg = 1, RRMTCT/preg = 1) and 25% (RRHIV/preg = 2, RRMTCT/preg = 4) to the reduction in the residual MTCT.Conclusion:Providing safe and effective microbicide to pregnant women in the context of wide-scale interventions would be desirable as it would increase the effectiveness of the intervention and significantly reduce the number of HIV infections acquired during pregnancy. The projected benefits from covering pregnant women by the HIV prevention programs is more substantial in communities in which the sexual risk during pregnancy is elevated. © 2013 Dimitrov et al

    The rolling problem: overview and challenges

    Full text link
    In the present paper we give a historical account -ranging from classical to modern results- of the problem of rolling two Riemannian manifolds one on the other, with the restrictions that they cannot instantaneously slip or spin one with respect to the other. On the way we show how this problem has profited from the development of intrinsic Riemannian geometry, from geometric control theory and sub-Riemannian geometry. We also mention how other areas -such as robotics and interpolation theory- have employed the rolling model.Comment: 20 page

    A Mathematical model for Astrocytes mediated LTP at Single Hippocampal Synapses

    Full text link
    Many contemporary studies have shown that astrocytes play a significant role in modulating both short and long form of synaptic plasticity. There are very few experimental models which elucidate the role of astrocyte over Long-term Potentiation (LTP). Recently, Perea & Araque (2007) demonstrated a role of astrocytes in induction of LTP at single hippocampal synapses. They suggested a purely pre-synaptic basis for induction of this N-methyl-D- Aspartate (NMDA) Receptor-independent LTP. Also, the mechanisms underlying this pre-synaptic induction were not investigated. Here, in this article, we propose a mathematical model for astrocyte modulated LTP which successfully emulates the experimental findings of Perea & Araque (2007). Our study suggests the role of retrograde messengers, possibly Nitric Oxide (NO), for this pre-synaptically modulated LTP.Comment: 51 pages, 15 figures, Journal of Computational Neuroscience (to appear

    Inhibition of Autoimmune Diabetes in NOD Mice by miRNA Therapy.

    Get PDF
    Autoimmune destruction of the pancreatic islets in Type 1 diabetes is mediated by both increased proinflammatory (Teff) and decreased regulatory (Treg) T lymphocytes resulting in a significant decrease in the Treg:Teff ratio. The non-obese diabetic (NOD) mouse is an excellent in vivo model for testing potential therapeutics for attenuating the decrease in the Treg:Teff ratio and inhibiting disease pathogenesis. Here we show for the first time that a bioreactor manufactured therapeutic consisting of a complex of miRNA species (denoted as TA1) can effectively reset the NOD immune system from a proinflammatory to a tolerogenic state thus preventing or delaying autoimmune diabetes. Treatment of NOD mice with TA1 resulted in a systemic broad-spectrum upregulation of tolerogenic T cell subsets with a parallel downregulation of Teff subsets yielding a dramatic increase in the Treg:Teff ratio. Moreover, the murine-derived TA1 was highly effective in the inhibition of allorecognition of HLA-disparate human PBMC. TA1 demonstrated dose-responsiveness and exhibited equivalent or better inhibition of allorecognition driven proliferation than etanercept (a soluble TNF receptor). These findings demonstrate that miRNA-based therapeutics can effectively attenuate or arrest autoimmune disease processes and may be of significant utility in a broad range of autoimmune diseases including Type 1 diabetes

    Evolving Synaptic Plasticity with an Evolutionary Cellular Development Model

    Get PDF
    Since synaptic plasticity is regarded as a potential mechanism for memory formation and learning, there is growing interest in the study of its underlying mechanisms. Recently several evolutionary models of cellular development have been presented, but none have been shown to be able to evolve a range of biological synaptic plasticity regimes. In this paper we present a biologically plausible evolutionary cellular development model and test its ability to evolve different biological synaptic plasticity regimes. The core of the model is a genomic and proteomic regulation network which controls cells and their neurites in a 2D environment. The model has previously been shown to successfully evolve behaving organisms, enable gene related phenomena, and produce biological neural mechanisms such as temporal representations. Several experiments are described in which the model evolves different synaptic plasticity regimes using a direct fitness function. Other experiments examine the ability of the model to evolve simple plasticity regimes in a task -based fitness function environment. These results suggest that such evolutionary cellular development models have the potential to be used as a research tool for investigating the evolutionary aspects of synaptic plasticity and at the same time can serve as the basis for novel artificial computational systems

    Childhood tuberculosis is associated with decreased abundance of T cell gene transcripts and impaired T cell function

    Get PDF
    The WHO estimates around a million children contract tuberculosis (TB) annually with over 80 000 deaths from dissemination of infection outside of the lungs. The insidious onset and association with skin test anergy suggests failure of the immune system to both recognise and respond to infection. To understand the immune mechanisms, we studied genome-wide whole blood RNA expression in children with TB meningitis (TBM). Findings were validated in a second cohort of children with TBM and pulmonary TB (PTB), and functional T-cell responses studied in a third cohort of children with TBM, other extrapulmonary TB (EPTB) and PTB. The predominant RNA transcriptional response in children with TBM was decreased abundance of multiple genes, with 140/204 (68%) of all differentially regulated genes showing reduced abundance compared to healthy controls. Findings were validated in a second cohort with concordance of the direction of differential expression in both TBM (r2 = 0.78 p = 2x10-16) and PTB patients (r2 = 0.71 p = 2x10-16) when compared to a second group of healthy controls. Although the direction of expression of these significant genes was similar in the PTB patients, the magnitude of differential transcript abundance was less in PTB than in TBM. The majority of genes were involved in activation of leucocytes (p = 2.67E-11) and T-cell receptor signalling (p = 6.56E-07). Less abundant gene expression in immune cells was associated with a functional defect in T-cell proliferation that recovered after full TB treatment (p<0.0003). Multiple genes involved in T-cell activation show decreased abundance in children with acute TB, who also have impaired functional T-cell responses. Our data suggest that childhood TB is associated with an acquired immune defect, potentially resulting in failure to contain the pathogen. Elucidation of the mechanism causing the immune paresis may identify new treatment and prevention strategies

    The Toll-Like Receptor Signaling Molecule Myd88 Contributes to Pancreatic Beta-Cell Homeostasis in Response to Injury

    Get PDF
    Commensal flora and pathogenic microbes influence the incidence of diabetes in animal models yet little is known about the mechanistic basis of these interactions. We hypothesized that Myd88, an adaptor molecule in the Toll-like-receptor (TLR) pathway, regulates pancreatic β-cell function and homeostasis. We first examined β-cells histologically and found that Myd88−/− mice have smaller islets in comparison to C57Bl/6 controls. Myd88−/− mice were nonetheless normoglycemic both at rest and after an intra-peritoneal glucose tolerance test (IPGTT). In contrast, after low-dose streptozotocin (STZ) challenge, Myd88−/−mice had an abnormal IPGTT relative to WT controls. Furthermore, Myd88−/− mice suffer enhanced β-cell apoptosis and have enhanced hepatic damage with delayed recovery upon low-dose STZ treatment. Finally, we treated WT mice with broad-spectrum oral antibiotics to deplete their commensal flora. In WT mice, low dose oral lipopolysaccharide, but not lipotichoic acid or antibiotics alone, strongly promoted enhanced glycemic control. These data suggest that Myd88 signaling and certain TLR ligands mediate a homeostatic effect on β-cells primarily in the setting of injury
    • …
    corecore