134 research outputs found
Ubiquitous lower-mantle anisotropy beneath subduction zones
Seismic anisotropy provides key information to map the trajectories of mantle flow and understand the evolution of our planet. While the presence of anisotropy in the uppermost mantle is well established, the existence and nature of anisotropy in the transition zone and uppermost lower mantle are still debated. Here we use three-dimensional global seismic tomography images based on a large dataset that is sensitive to this region to show the ubiquitous presence of anisotropy in the lower mantle beneath subduction zones. Whereas above the 660 km seismic discontinuity slabs are associated with fast SV anomalies up to about 3%, in the lower mantle fast SH anomalies of about 2% persist near slabs down to about 1,000–1,200 km. These observations are consistent with 3D numerical models of deformation from subducting slabs and the associated lattice-preferred orientation of bridgmanite produced in the dislocation creep regime in areas subjected to high stresses. This study provides evidence that dislocation creep may be active in the Earth’s lower mantle, providing new constraints on the debated nature of deformation in this key, but inaccessible, component of the deep Earth
Development of a Socially Believable Multi-Robot Solution from Town to Home
Technological advances in the robotic and ICT fields represent an effective solution to address specific societal problems to support ageing and independent life. One of the key factors for these technologies is that they have to be socially acceptable and believable to the end-users. This paper aimed to present some technological aspects that have been faced to develop the Robot-Era system, a multi-robotic system that is able to act in a socially believable way in the environments daily inhabited by humans, such as urban areas, buildings and homes. In particular, this paper focuses on two services—shopping delivery and garbage collection—showing preliminary results on experiments conducted with 35 elderly people. The analysis adopts an end-user-oriented perspective, considering some of the main attributes of acceptability: usability, attitude, anxiety, trust and quality of life
hepatocellular carcinoma is the most frequent final diagnosis of focal liver lesions identified in a cross sectional evaluation of patients with chronic liver disease in saudi arabia
Background.Hepatocellular carcinoma (HCC) is a frequent diagnosis in patients with chronic liver disease (CLD) and a newly identified liver lesion, although benign diseases may also be responsible for this finding.Objective.To evaluate the characteristics of focal liver lesions in a population of patients with CLD not under surveillance for HCC in the Middle East.Methods.We performed a cross-sectional study evaluating 77 patients with CLD and a focal liver lesion identified during ultrasonography. Patients' characteristics were analyzed on the basis of the final diagnosis (HCC versus benign lesions).Results.The most frequent diagnosis was HCC (64.9%). These patients were older (median age 64 versus 55 years,P=0.003) and cirrhotics (80.0% versus 51.9%,P=0.018), with multinodular lesions (58.0% versus 29.6%,P=0.031) and portal vein thrombosis (24.0% versus 0%,P=0.001) compared to patients with benign lesions. Prevalence of elevated alpha-fetoprotein (>10 ng/mL) was similar in both groups (80.0% versus 88.9%,P=0.198). Cirrhosis (odds ratio: 3.283) and multinodularity (odds ratio: 2.898) were independently associated with HCC.Conclusions.HCC is the most common diagnosis in Middle-Eastern patients with CLD and a liver lesion identified outside HCC surveillance programs, especially in cirrhotic patients. In these patients, elevated alpha-fetoprotein does not differentiate HCC from benign lesions
Seven-body central configurations: a family of central configurations in the spatial seven-body problem
The main result of this paper is the existence of a new family of central
configurations in the Newtonian spatial seven-body problem. This family is
unusual in that it is a simplex stacked central configuration, i.e the bodies
are arranged as concentric three and two dimensional simplexes.Comment: 15 pages 5 figure
A Planner for Ambient Assisted Living: From High-Level Reasoning to Low-Level Robot Execution and Back
Robot ecologies are a growing paradigm in which one or several robotic systems are integrated into a smart environment. Robotic ecologies hold great promises for elderly assistance. Planning the activities of these systems, however, is not trivial, and requires consideration of issues like temporal and information dependencies among different parts of the ecology, exogenous actions, and multiple, dynamic goals. We describe a planner able to cope with the above challenges. We show in particular how this planner has been incorporated in closed-loop into a full robotic system that performs daily tasks in support of elderly people. The full robot ecology is deployed in a test apartment inside a real residential building, and it is currently undergoing an extensive user evaluation
Pest Management in Grain Legumes: Potential and Limitations
Grain legumes such as chickpea, pigeonpea, cowpea, field pea , lentil, ,
and Phaseolus beans are the principal source of dietary protein among vegetarians,
and are an integral part of daily diet in several forms worldwide. They are an
important component of cropping systems to maintain soil fertility because of
their ability to fix atmospheric nitrogen, extract water and nutrients from the
deeper layers of the soil as compared to cereals, and add organic matter into the
soil through leaf drop. However, grain legumes are mainly grown under rainfed
conditions and the productivity levels are quite low mainly because of severe
losses due to insect pests and diseases. Average grain yield of pulses (0.86 t/
ha) is only about onefourth
the average yields of cereals (3.54 t/ha). Production
and productivity of grain legumes is constrained by several biotic and abiotic
factors, and suffer an average of 31.9 to 69.6% loss in crop productivity due to
insects, diseases, drought, weeds, and soil fertility. Pod borers (Helicoverpa
and Maruca), Fusarium wilts, viral diseases, Ascochyta blight and Botrytis gray
mold (Chen et al., 2011)..
Relative Equilibria in the Four-Vortex Problem with Two Pairs of Equal Vorticities
We examine in detail the relative equilibria in the four-vortex problem where
two pairs of vortices have equal strength, that is, \Gamma_1 = \Gamma_2 = 1 and
\Gamma_3 = \Gamma_4 = m where m is a nonzero real parameter. One main result is
that for m > 0, the convex configurations all contain a line of symmetry,
forming a rhombus or an isosceles trapezoid. The rhombus solutions exist for
all m but the isosceles trapezoid case exists only when m is positive. In fact,
there exist asymmetric convex configurations when m < 0. In contrast to the
Newtonian four-body problem with two equal pairs of masses, where the symmetry
of all convex central configurations is unproven, the equations in the vortex
case are easier to handle, allowing for a complete classification of all
solutions. Precise counts on the number and type of solutions (equivalence
classes) for different values of m, as well as a description of some of the
bifurcations that occur, are provided. Our techniques involve a combination of
analysis and modern and computational algebraic geometry
Identification of a novel zinc metalloprotease through a global analysis of clostridium difficile extracellular proteins
Clostridium difficile is a major cause of infectious diarrhea worldwide. Although the cell surface proteins are recognized to be important in clostridial pathogenesis, biological functions of only a few are known. Also, apart from the toxins, proteins exported by C. difficile into the extracellular milieu have been poorly studied. In order to identify novel extracellular factors of C. difficile, we analyzed bacterial culture supernatants prepared from clinical isolates, 630 and R20291, using liquid chromatography-tandem mass spectrometry. The majority of the proteins identified were non-canonical extracellular proteins. These could be largely classified into proteins associated to the cell wall (including CWPs and extracellular hydrolases), transporters and flagellar proteins. Seven unknown hypothetical proteins were also identified. One of these proteins, CD630_28300, shared sequence similarity with the anthrax lethal factor, a known zinc metallopeptidase. We demonstrated that CD630_28300 (named Zmp1) binds zinc and is able to cleave fibronectin and fibrinogen in vitro in a zinc-dependent manner. Using site-directed mutagenesis, we identified residues important in zinc binding and enzymatic activity. Furthermore, we demonstrated that Zmp1 destabilizes the fibronectin network produced by human fibroblasts. Thus, by analyzing the exoproteome of C. difficile, we identified a novel extracellular metalloprotease that may be important in key steps of clostridial pathogenesis
One year after on Tyrrhenian coasts: The ban of cotton buds does not reduce their dominance in beach litter composition
In January 2019, Italy banned the sale of plastic cotton buds, which is one of the most abundant litter items entering the sea and then washing ashore. However, since the ban came into force, no studies have been carried out to assess whether the measure has actually led to the reduction of plastic cotton buds accumulating on Italian coasts. Here we aim at evaluating the effectiveness of the ban in reducing the amount of cotton buds reaching sandy beaches of the Tyrrhenian coast. Specifically, we monitored the accumulation of beach litter for one year since the ban came into force. By surveying eight coastal sites from winter 2019 to winter 2020, we collected a total of 52,824 items mostly constituted by plastic debris (97.6%). We found that cotton buds were the most abundant item (42.3% of total litter), followed by plastic (28.5%) and polystyrene (5.43%) fragments. Our preliminary assessment suggests that the ban has so far not led to a sensible reduction in the amount of cotton buds entering the marine ecosystem. This was to be expected since implementation strategies are still lacking (i.e. no economic sanctions can be imposed in case of non-compliance) and bans are differently implemented among countries facing the Mediterranean Sea, calling for law enforcement and implementation at the national and international levels
Lopinavir/ritonavir and darunavir/cobicistat in hospitalized covid-19 patients: Findings from the multicenter italian corist study
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