7,964 research outputs found
Microplastic incorporation into soil in agroecosystems
Background: We live in a plastic age (Thompson et al., 2009), with
microplastic (typically defined as plastic particles < 5 mm) becoming an
increasingly appreciated aspect of environmental pollution. Research has been
overwhelmingly focused on aquatic systems, especially the oceans, but there is
a current shift to more strongly consider terrestrial ecosystems (Rillig,
2012; Horton et al., 2017). In particular agroecosystems are coming into focus
as a major entry point for microplastics in continental systems (Nizzetto et
al., 2016b), where contamination might occur via different sources as sludge
amendment or plastic mulching (Steinmetz et al., 2016). Given the central role
of agroecosystems, including their soil biodiversity (Rillig et al., 2016), in
food production, such numbers are potential cause for concern. Field data on
measured microplastic presence in agricultural soils are still not widely
available, but nevertheless this material is certain to arrive at the soil
surface. The fate of material deposited at the soil surface is not clear:
particles may be removed by wind or water erosion, becoming airborne, or may
be lost by surface runoff (Nizzetto et al., 2016a). Nevertheless, a
substantial part of the microplastic (or nanoplastic following further
disintegration) is expected to enter the soil. The degree of hazard
represented by microplastic to various soil biota is not clear. Direct
evidence comes from experimental work on earthworms, on which microbeads had
negative effects (Huerta Lwanga et al., 2016; also reviewed in Horton et al.,
2017). Data on impacts on other soil biota groups are not available. However,
Kiyama et al. (2012) have shown that polystyrene beads can be taken up by the
nematode Caenorhabditis elegans; this means the material could also accumulate
in the soil food web (Rillig, 2012). Movement into soil is an important aspect
of assessing risk: will soil biota be exposed to microplastics? Here, we
sketch what is known about movement of such particles in soil, which players
and factors could influence this, and we chart avenues for research aimed at
the movement and distribution of microplastic in agricultural soils
Estimating Self-Sustainability in Peer-to-Peer Swarming Systems
Peer-to-peer swarming is one of the \emph{de facto} solutions for distributed
content dissemination in today's Internet. By leveraging resources provided by
clients, swarming systems reduce the load on and costs to publishers. However,
there is a limit to how much cost savings can be gained from swarming; for
example, for unpopular content peers will always depend on the publisher in
order to complete their downloads. In this paper, we investigate this
dependence. For this purpose, we propose a new metric, namely \emph{swarm
self-sustainability}. A swarm is referred to as self-sustaining if all its
blocks are collectively held by peers; the self-sustainability of a swarm is
the fraction of time in which the swarm is self-sustaining. We pose the
following question: how does the self-sustainability of a swarm vary as a
function of content popularity, the service capacity of the users, and the size
of the file? We present a model to answer the posed question. We then propose
efficient solution methods to compute self-sustainability. The accuracy of our
estimates is validated against simulation. Finally, we also provide closed-form
expressions for the fraction of time that a given number of blocks is
collectively held by peers.Comment: 27 pages, 5 figure
In Vivo Comparison of 23-and 25-Gauge Sutureless Vitrectomy Incision Architecture Using Spectral Domain Optical Coherence Tomography
Purpose. To investigate the in vivo incision architecture using spectral domain optical coherence tomography (SD-OCT) in 23-gauge and 25-gauge transconjunctival sutureless pars plana vitrectomy (TSPPV). Methods. A prospective observational study of 22 eyes of 22 patients that underwent three-port 25-gauge (10 eyes) or 23-gauge (12 eyes) TSPPV was performed. the three sclerotomies sites in each eye were analyzed by Corneal Adapter Model (CAM) RTVue SD-OCT (Optovue Inc., Fremont, CA, USA) with wound cross-section images (longitudinal and transversal) on days 1, 7, and 30 postoperatively. Transversal and longitudinal length, location, angle between the conjunctival surface tangent and the incision plane, and architecture deformations were evaluated. Results. All patients (22 eyes) completed the study and surgeries lasted less than 60 minutes. All wounds were obliquely performed, 23-gauge mean angle was 23 +/- 5 degrees, and 25-gauge angule was 21 +/- 4 degrees. Twenty-three-gauge sclerotomy transversal mean length was 1122 +/- 242 mu m and 25-gauge transversal sclerotomy mean length was 977 +/- 174 mu m; 23-gauge longitudinal mean length was 363 +/- 42 mu m and 25-gauge longitudinal sclerotomy mean length was 234 +/- 19 mu m; 23-gauge open wound thickness mean was 61 +/- 28 mu m and 25-gauge open wound thickness mean was 22 +/- 6 mu m. All results were statistically significant (P < 0.05). No vitreous incarceration or silicone oil residue was observed in incision sites with both gauges. Conclusions. the 23-gauge and 25-gauge architectural wound constructions were well visualized using CAM SD-OCT. Statistical differences between the two gauges were observed throughout the study period.Teixeira Oftalmol, BR-70392901 Brasilia, DF, BrazilUniversidade Federal de São Paulo, Dept Ophthalmol, São Paulo, BrazilUniv Catolica Brasilia, Dept Ophthalmol, Brasilia, DF, BrazilUniv Montreal, Dept Ophthalmol, Hop Maisonneuve Rosemont, Montreal, PQ, CanadaPontificia Univ Catolica Rio de Janeiro, Dept Ophthalmol, Rio de Janeiro, RJ, BrazilUniv Illinois, Dept Ophthalmol, Chicago, IL 60680 USAUniversidade Federal de São Paulo, Dept Ophthalmol, São Paulo, BrazilWeb of Scienc
Hyponatremia and Psychiatric Diseases
Eating disorders, psychotic illnesses, and substance use disorders are some of the more common psychiatric conditions encountered in clinical practice that are associated with hyponatremia. The mechanisms that lead to hyponatremia vary, and at times hyponatremia may be a result of a drug side effect or drug-drug interaction. Additionally, hyponatremia from a non-psychiatric condition may lead to psychiatric symptomatology. Given the potential for hyponatremia to cause significant morbidity and potential mortality, clinicians are urged to consider screening for plasma sodium in patients at risk of hyponatremia, such as patients in the three categories of psychiatric conditions described above. Treatment of hyponatremia consists of various acute interventions, with consideration that treatment of the underlying psychiatric condition may help to diminish or eliminate the frequency of hyponatremic episodes in the long run
Intermittent applied mechanical loading induces subchondral bone thickening that may be intensified locally by contiguous articular cartilage lesions
Objectives: Changes in subchondral bone (SCB) and cross-talk with articular cartilage (AC) have been linked to osteoarthritis (OA). Using micro-computed tomography (micro-CT) this study: (1) examines changes in SCB architecture in a non-invasive loading mouse model in which focal AC lesions are induced selectively in the lateral femur, and (2) determines any modifications in the contralateral knee, linked to changes in gait, which might complicate use of this limb as an internal control. Methods: Right knee joints of CBA mice were loaded: once with 2weeks of habitual use (n=7), for 2weeks (n=8) or for 5weeks (n=5). Both left (contralateral) and right (loaded) knees were micro-CT scanned and the SCB and trabecular bone analysed. Gait analysis was also performed. Results: These analyses showed a significant increase in SCB thickness in the lateral compartments in joints loaded for 5weeks, which was most marked in the lateral femur; the contralateral non-loaded knee also showed transient SCB thickening (loaded once and repetitively). Epiphyseal trabecular bone BV/TV and trabecular thickness were also increased in the lateral compartments after 5 weeks of loading, and in all joint compartments in the contralateral knee. Gait analysis showed that applied loading only affected gait in the contralateral himd-limb in all groups of mice from the second week after the first loading episode. Conclusions: These data indicate a spatial link between SCB thickening and AC lesions following mechanical trauma, and the clear limitations associated with the use of contralateral joints as controls in such OA models, and perhaps in OA diagnosis
Acid decomposition of yerba mate (ilex paraguariensis) using a reflux system for the evaluation of Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Pb and Zn contents by atomic spectrometric techniques
In the first part of this paper, two acid decomposition procedures for the determination of Al, Ca, Fe, Mg, Mn and Zn contents in yerba mate samples by inductively coupled plasma optical emission spectrometry (ICP OES) were compared. Using a reflux system, the samples were treated with a mixture of HNO3 and H2O2 for 3 hours at 220 °C in the digester block. The results from five commercial yerba mate samples were compared with the results obtained from microwave digestion. Good agreement between the procedures at a 95% confidence level was obtained with relative standard deviation (RSD) values lower than 10.0%. The accuracy was evaluated using addition and recovery experiments (80.5 to 112.8%). In the second part, Ca, Cd, Cr, Cu, Fe, K, Mg, Na, Pb and Zn concentrations were evaluated in the yerba mate infusion. The results showed that elements such as Na, K, Mg and Zn are easily transferred to the hot water used for the infusion. For Pb and Cd, the concentrations found in the analyzed samples were lower than the values established by Brazilian legislation274685693CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGSSem informação552197/2011-4Sem informaçã
Simulating nearly edge-on sloshing in the galaxy cluster Abell 2199
Off-axis collisions between galaxy clusters may induce the phenomenon of
sloshing, causing dense gas to be dragged from the cool core of a cluster,
resulting in a spiral of enhanced X-ray emission. Abell 2199 displays
signatures of sloshing in its core and it is possible that the orbital plane of
the collision is seen nearly edge-on. We aim to evaluate whether the features
of Abell 2199 can be explained by a sloshing spiral seen under a large
inclination angle. To address this, we perform tailored hydrodynamical -body
simulations of a non-frontal collision with a galaxy group of
. We obtain a suitable scenario in
which the group passed by the main cluster core 0.8 Gyr ago, with a pericentric
separation of 292 kpc. Good agreement is obtained from the temperature maps as
well as the residuals from a -model fit to the simulated X-ray emission.
We find that under an inclination of the simulation results
remain consistent with the observations.Comment: 13 pages, 14 figures, accepted for publication in MNRAS; replaced
Fig.
Facial onset sensory and motor neuronopathy: new cases, cognitive changes and pathophysiology
Purpose of review To improve our clinical understanding of facial onset sensory and motor neuronopathy (FOSMN).
Recent findings We identified 29 new cases and 71 literature cases, resulting in a cohort of 100 patients with FOSMN. During follow-up, cognitive and behavioral changes became apparent in 8 patients, suggesting that changes within the spectrum of frontotemporal dementia (FTD) are a part of the natural history of FOSMN. Another new finding was chorea, seen in 6 cases. Despite reports of autoantibodies, there is no consistent evidence to suggest an autoimmune pathogenesis. Four of 6 autopsies had TAR DNA-binding protein (TDP) 43 pathology. Seven cases had genetic mutations associated with neurodegenerative diseases.
Summary FOSMN is a rare disease with a highly characteristic onset and pattern of disease progression involving initial sensory disturbances, followed by bulbar weakness with a cranial to caudal spread of pathology. Although not conclusive, the balance of evidence suggests that FOSMN is most likely to be a TDP-43 proteinopathy within the amyotrophic lateral sclerosis–FTD spectrum
Studies on variation of carotenoid-proteins content in Cassava (Manihot esculenta Crantz) storage root reveal implications for breeding and the use of induced mutations.
Carotenoid-Protein content in cassava storage root (CSR) is low but variable, and characterization of this variability is lacking. Accumulation of carotenoids occurs in chromoplast and depends on a broad class of proteins named carotenoid associated proteins (CAP), lipids and the biosynthesis of carotenoids. Twenty-nine landraces and progeny of 200 individuals were accessed for CAP and carotenoid content varied in two ways. First, related to landrace diversity, total buffer extractable proteins (TBEP), buffer insoluble proteins (BIP) and total carotenoid and ?-carotene content were assessed. Significant differences were observed in the tested genotypes. Secondly, analyses related to storage root tissue age were assessed by TBEP. This showed protein content decreased and total carotenoid content increased as secondary growth proceeds. Further carotenoid-proteins complex (CPC) identified in carotenoid contrasting landraces showed different proteins profile in SDS-PAGE with proteins size of 18 and 33 kDa in low carotenoid (IAC12.829) and 18-20-30-33 kDa in a high total carotenoid landrace (Cas74.1). Progeny analysis for TBEP and total carotenoid content confirmed the interdependence of carotenoid-proteins association by correlation analysis, estimated heritability of individual traits and grouping clones for carotenoid-proteins content. Results allow us to conclude that: natural carotenoid-protein content varies due to differential genetic background and storage root tissue age; carotenoid-protein complex showed variation in protein and carotenoid types; estimated heritability of proteins and carotenoids traits showed different values. The establishment of a genetic component allows future strategies including traditional breeding and the use of induced mutations to create novel variation for the nutritional improvement of cassava tubers
- …