Histological validation of the brain cell body imaging with diffusion MRI at ultrahigh field

Biophysical modelling of diffusion-weighted MRI (DW-MRI) data can help to gain more insight into brain microstructure. However, models need to be validated. This work validates a recently-developed technique for non-invasive mapping of brain cell-body (soma) size/ density with DW-MRI, by using ultrahigh-field DW-MRI experiments and histology of mouse brain. Predictions from numerical simulations are experimentally confirmed and brain’s maps of MR-measured soma size/density are shown to correspond very well with histology. We provide differential contrasts between cell layers that are less expressed in tensor analyses, leading to novel complementary contrasts of the brain tissue. Limitations and future research directions are discussed

Cluster approximations for infection dynamics on random networks

In this paper, we consider a simple stochastic epidemic model on large regular random graphs and the stochastic process that corresponds to this dynamics in the standard pair approximation. Using the fact that the nodes of a pair are unlikely to share neighbors, we derive the master equation for this process and obtain from the system size expansion the power spectrum of the fluctuations in the quasi-stationary state. We show that whenever the pair approximation deterministic equations give an accurate description of the behavior of the system in the thermodynamic limit, the power spectrum of the fluctuations measured in long simulations is well approximated by the analytical power spectrum. If this assumption breaks down, then the cluster approximation must be carried out beyond the level of pairs. We construct an uncorrelated triplet approximation that captures the behavior of the system in a region of parameter space where the pair approximation fails to give a good quantitative or even qualitative agreement. For these parameter values, the power spectrum of the fluctuations in finite systems can be computed analytically from the master equation of the corresponding stochastic process.Comment: the notation has been changed; Ref. [26] and a new paragraph in Section IV have been adde

Are spectroscopic factors from transfer reactions consistent with asymptotic normalisation coefficients?

It is extremely important to devise a reliable method to extract spectroscopic factors from transfer cross sections. We analyse the standard DWBA procedure and combine it with the asymptotic normalisation coefficient, extracted from an independent data set. We find that the single particle parameters used in the past generate inconsistent asymptotic normalization coefficients. In order to obtain a consistent spectroscopic factor, non-standard parameters for the single particle overlap functions can be used but, as a consequence, often reduced spectroscopic strengths emerge. Different choices of optical potentials and higher order effects in the reaction model are also studied. Our test cases consist of: $^{14}$C(d,p)$^{15}$C(g.s.) at $E_d^{lab}=14$ MeV, $^{16}$O(d,p)$^{17}$O(g.s.) at $E_d^{lab}=15$ MeV and $^{40}$Ca(d,p)$^{41}$Ca(g.s.) at $E_d^{lab}=11$ MeV. We underline the importance of performing experiments specifically designed to extract ANCs for these systems.Comment: 15 pages, 12 figures, Phys. Rev. C (in press

Calculations of three-body observables in ^8B breakup

We discuss calculations of three-body observables for the breakup of ^8B on a ^{58}Ni target at low energy using the coupled discretised continuum channels approach. Calculations of both the angular distribution of the ^7Be fragments and their energy distributions are compared with those measured at several laboratory angles. In these observables there is interference between the breakup amplitudes from different spin-parity excitations of the projectile. The resulting angle and the energy distributions reveal the importance of the higher-order continuum state couplings for an understanding of the measurements.Comment: 22 pages (postscript), accepted in Phys. Rev.

Evaluation of the toxicity of the mixture of diflubenzuron and p-chloroaniline in tilapia fish in the presence and absence of soil.

aBSTRACT: Several chemicals occur together in the environment as a result of different sources. However, in the great majority of risk assessments only a single chemical is considered. Diflubenzuron (DFB), the most used compound to combat parasites in aquaculture, can be toxic for non-target species. When degraded, it generates p-chloroaniline (PCA), a potentially carcinogenic and mutagenic compound. This study analyzed the activity of the enzymes: Catalase (CAT), acid and alkaline Phosphatase (ACP/ALP) of the gills of the Tilapia fish (Oreochromis niloticus) exposed to different concentrations of the mixture of DFB and PCA in the presence and absence of soil

On virialization with dark energy

We review the inclusion of dark energy into the formalism of spherical collapse, and the virialization of a two-component system, made of matter and dark energy. We compare two approaches in previous studies. The first assumes that only the matter component virializes, e.g. as in the case of a classic cosmological constant. The second approach allows the full system to virialize as a whole. We show that the two approaches give fundamentally different results for the final state of the system. This might be a signature discriminating between the classic cosmological constant which cannot virialize and a dynamical dark energy mimicking a cosmological constant. This signature is independent of the measured value of the equation of state. An additional issue which we address is energy non-conservation of the system, which originates from the homogeneity assumption for the dark energy. We propose a way to take this energy loss into account.Comment: 15 pages, 5 figures. Accepted for publication in JCA

Implementation of digital health in rural populations with chronic musculoskeletal conditions: A scoping review protocol

Musculoskeletal conditions are a major source of disability worldwide, and its burden have been rising in the last decades. Rural areas, in particular, are associated with higher prevalence of these conditions as well as higher levels of disability, which is likely related to other determinants that affect these communities. Although digital health has been identified as a potential solution to mitigate the impact of these determinants, it is also known that these populations may face barriers that limit the implementation of these interventions. Therefore, the aim of this scoping review is to comprehensively map the evidence regarding the implementation of digital health interventions in rural populations with chronic musculoskeletal conditions. We will include studies published from the year 2000; that report the use of digital interventions that promote prevention, treatment or monitoring of any chronic musculoskeletal condition or chronic pain from musculoskeletal origin, in patients that live in rural areas. This protocol follows the methodological framework for scoping reviews proposed by Arksey and O'Malley, as well as the Joana Briggs Institute (JBI) approach. We will conduct the search on Medline (PubMed), EMBASE, Web of Science and Scopus, as well as grey literature databases. Two independent reviewers will screen titles and abstracts followed by a full-text review to assess the eligibility of the articles. Data extracted will include the identification of the digital interventions used, barriers and enablers identified by the patients or healthcare providers, the patient-level outcomes measured, and the implementation strategies and outcomes reported. By mapping the evidence on the implementation of digital health interventions in rural communities with musculoskeletal conditions, this scoping review will enhance our understanding of their applicability in real-world settings.info:eu-repo/semantics/publishedVersio

Earthworm diversity in four land use systems in the region of Jaguapitã, Paraná State, Brazil.

Little infonnation is available on earthwonn distribution and diversity in the State of Paraná, southern Brazil, Earthwonn abundanee and species diversity was evaluated in four land use systems near [aguapítã, (Paraná); where pastures are being eonverted to soybean and sugarcane. Samples were taken during the rainy and dry seasons of 2004 and 2005 in eight sites: two old degraded pastures, an old pasture being eonverted to row eropping, two grain erop fields, two sugareane fields and a native forest fragmento Twentyfive 25 x 25 em soil bloeks were taken at eaeh síte, 20 of them to 10 em and five to 30 em depth. Earthwonns were manually sorted from the soil and preserved in fonnaldehyde. Earthwonn species found were: the exotics Pontoscolex corethrurus (Glossoscolecidae), Dichogaster affinis, D. bolaui and D. saliens (Acanthodrí- Iidae), Eukerria saltensis, E. eiseniana and Ocnerodrilus occidentalis (Ocnerodrilídae), and Amynthas sp. (Megascolecidae): the native species Glossoscolex n. sp. and Fimoscolex n. sp. (Glossoscolecidae), Belladrilus n. sp.l and an unidentifiable Oenerodrilidae n, sp.l (probably Belladrílus); and two unidentified Eukerria spp. (of unknown origin) (Oenerodrilidae). Pasture eonversion to row erops had a negative effect on earthwonn abundanee and diversity: fewer individuais and species were found in the eropping systems than the pastures. The forest was not a suitable referenee site, having low earthworm populations and diversity. Exotie species tended to predominate in the land use systems near [aguapítã, but native earthworm species still survived, even in degraded pastures and row erops, many years after deforestation