In the past years, mass univariate statistical analyses of neuroimaging data have been complemented by the use of multivariate pattern analyses, especially based on machine learning models. While ...these allow an increased sensitivity for the detection of spatially distributed effects compared to univariate techniques, they lack an established and accessible software framework. The goal of this work was to build a toolbox comprising all the necessary functionalities for multivariate analyses of neuroimaging data, based on machine learning models. The “Pattern Recognition for Neuroimaging Toolbox” (PRoNTo) is open-source, cross-platform, MATLAB-based and SPM compatible, therefore being suitable for both cognitive and clinical neuroscience research. In addition, it is designed to facilitate novel contributions from developers, aiming to improve the interaction between the neuroimaging and machine learning communities. Here, we introduce PRoNTo by presenting examples of possible research questions that can be addressed with the machine learning framework implemented in PRoNTo, and cannot be easily investigated with mass univariate statistical analysis.
Ultrafast processes in matter, such as the electron emission after light absorption, can now be studied using ultrashort light pulses of attosecond duration (10−18 seconds) in the extreme ultraviolet ...spectral range. The lack of spectral resolution due to the use of short light pulses has raised issues in the interpretation of the experimental results and the comparison with theoretical calculations. We determine photoionization time delays in neon atoms over a 40–electron volt energy range with an interferometric technique combining high temporal and spectral resolution. We spectrally disentangle direct ionization from ionization with shake-up, in which a second electron is left in an excited state, and obtain excellent agreement with theoretical calculations, thereby solving a puzzle raised by 7-year-old measurements.
The limit of application of the Scherrer equation Miranda, M. A. R.; Sasaki, J. M.
Acta crystallographica. Section A, Foundations and advances,
January 2018, 2018-Jan-01, 2018-01-01, 20180101, Letnik:
74, Številka:
1
Journal Article
Recenzirano
The Scherrer equation is a widely used tool to obtain crystallite size from polycrystalline samples. Its limit of applicability has been determined recently, using computer simulations, for a few ...structures and it was proposed that it is directly dependent on the linear absorption coefficient (μ0) and Bragg angle (gθB). In this work, a systematic study of the Scherrer limit is presented, where it is shown that it is equal to approximately 11.9% of the extinction length. It is also shown that absorption imposes a maximum value on it and that this maximum is directly proportional to sin gθB/μ0.
Study of the limit of applicability of the Scherrer equation has found it is approximately 11.9% of the extinction length and has a maximum value because of absorption.
Objective
To assess the association and magnitude of the effect of early exposure to different types of interpersonal violence (IPV) with suicide attempt and suicide death in youths and young adults.
...Method
We searched six databases until June 2015. Inclusion criteria were as follows: (1) assessment of any type of IPV as risk factor of suicide attempt or suicide: (i) child maltreatment childhood physical, sexual, emotional abuse, neglect, (ii) bullying, (iii) dating violence, and (iv) community violence; (2) population‐based case–control or cohort studies; and (3) subjects aged 12–26 years. Random models were used for meta‐analyses (Reg: CRD42013005775).
Results
From 23 682 articles, 29 articles with 143 730 subjects for meta‐analyses were included. For victims of any IPV, OR of subsequent suicide attempt was 1.99 (95% CI: 1.73–2.28); for child maltreatment, 2.25 (95% CI: 1.85–2.73); for bullying, 2.39 (95% CI: 1.89–3.01); for dating violence, 1.65 (95% CI: 1.40–1.94); and for community violence, 1.48 (95% CI: 1.16–1.87). Young victims of IPV had an OR of suicide death of 10.57 (95% CI: 4.46–25.07).
Conclusion
Early exposure to IPV confers a risk of suicide attempts and particularly suicide death in youths and young adults. Future research should address the effectiveness of preventing and detecting early any type of IPV exposure in early ages.
Aim: Mediterranean terrestrial ecosystems serve as reference laboratories for the investigation of global change because of their transitional climate, the high spatiotemporal variability of their ...environmental conditions, a rich and unique biodiversity and a wide range of socio-economic conditions. As scientific development and environmental pressures increase, it is increasingly necessary to evaluate recent progress and to challenge research priorities in the face of global change. Location: Mediterranean terrestrial ecosystems. Methods: This article revisits the research priorities proposed in a 1998 assessment. Results: A new set of research priorities is proposed: (1) to establish the role of the landscape mosaic on fire-spread; (2) to further research the combined effect of different drivers on pest expansion; (3) to address the interaction between drivers of global change and recent forest management practices; (4) to obtain more realistic information on the impacts of global change and ecosystem services; (5) to assess forest mortality events associated with climatic extremes; (6) to focus global change research on identifying and managing vulnerable areas; (7) to use the functional traits concept to study resilience after disturbance; (8) to study the relationship between genotypic and phenotypic diversity as a source of forest resilience; (9) to understand the balance between storage and water resources; (10) to analyse the interplay between landscape-scale processes and biodiversity conservation; (11) to refine models by including interactions between drivers and socio-economic contexts; (12) to understand forest-atmosphere feedbacks; (13) to represent key mechanisms linking plant hydraulics with landscape hydrology. Main conclusions: (1) The interactive nature of different global change drivers remains poorly understood. (2) There is a critical need for the rapid development of regional-and global-scale models that are more tightly connected with largescale experiments, data networks and management practice. (3) More attention should be directed to drought-related forest decline and the current relevance of historical land use.
Electron dynamics induced by resonant absorption of light is of fundamental importance in nature and has been the subject of countless studies in many scientific areas. Above the ionization threshold ...of atomic or molecular systems, the presence of discrete states leads to autoionization, which is an interference between two quantum paths: direct ionization and excitation of the discrete state coupled to the continuum. Traditionally studied with synchrotron radiation, the probability for autoionization exhibits a universal Fano intensity profile as a function of excitation energy. However, without additional phase information, the full temporal dynamics cannot be recovered. Here we use tunable attosecond pulses combined with weak infrared radiation in an interferometric setup to measure not only the intensity but also the phase variation of the photoionization amplitude across an autoionization resonance in argon. The phase variation can be used as a fingerprint of the interactions between the discrete state and the ionization continua, indicating a new route towards monitoring electron correlations in time.
IMPORTANCE: The etiologic factors of late-life depression are still poorly understood. Recent evidence suggests that microvascular dysfunction is associated with depression, which may have ...implications for prevention and treatment. However, this association has not been systematically reviewed. OBJECTIVE: To examine the associations of peripheral and cerebral microvascular dysfunction with late-life depression. DATA SOURCES: A systematic literature search was conducted in MEDLINE and EMBASE for and longitudinal studies published since inception to October 16, 2016, that assessed the associations between microvascular dysfunction and depression. STUDY SELECTION: Three independent researchers performed the study selection based on consensus. Inclusion criteria were a study population 40 years of age or older, a validated method of detecting depression, and validated measures of microvascular function. DATA EXTRACTION AND SYNTHESIS: This systematic review and meta-analysis has been registered at PROSPERO (CRD42016049158) and is reported in accordance with the PRISMA and MOOSE guidelines. Data extraction was performed by an independent researcher. MAIN OUTCOMES AND MEASURES: The following 5 estimates of microvascular dysfunction were considered in participants with or without depression: plasma markers of endothelial function, albuminuria, measurements of skin and muscle microcirculation, retinal arteriolar and venular diameter, and markers for cerebral small vessel disease. Data are reported as pooled odds ratios (ORs) by use of the generic inverse variance method with the use of random-effects models. RESULTS: A total of 712 studies were identified; 48 were included in the meta-analysis, of which 8 described longitudinal data. Data from 43 600 participants, 9203 individuals with depression, and 72 441 person-years (mean follow-up, 3.7 years) were available. Higher levels of plasma endothelial biomarkers (soluble intercellular adhesion molecule–1: OR, 1.58; 95% CI, 1.28-1.96), white matter hyperintensities (OR, 1.29; 95% CI, 1.19-1.39), cerebral microbleeds (OR, 1.18; 95% CI, 1.03-1.34), and cerebral (micro)infarctions (OR, 1.30; 95% CI, 1.21-1.39) were associated with depression. Among the studies available, no significant associations of albuminuria and retinal vessel diameters with depression were reported. Longitudinal data showed a significant association of white matter hyperintensities with incident depression (OR, 1.19; 95% CI, 1.09-1.30). CONCLUSIONS AND RELEVANCE: This meta-analysis shows that both the peripheral and cerebral forms of microvascular dysfunction are associated with higher odds of (incident) late-life depression. This finding may have clinical implications because microvascular dysfunction might provide a potential target for the prevention and treatment of depression.
Active predators obtain energy and nutrients from prey through complex processes in which the energy gained must exceed the energy invested in finding and ingesting the prey. In addition, the amount ...of energy available will vary with the prey that are selected for consumption. The muricid gastropod Acanthina monodon inhabits rocky shores, where it routinely feeds on the mytilids Semimytilus algosus and Perumytilus purpuratus. In this study, S. algosus was highly preferred by the predator (over 90% were eaten) versus P. purpuratus (only 9% were eaten) when offered a mixed diet. The energetic cost of attacking one S. algosus individual was 91 J bivalve-1 while for P. purpuratus it was slightly higher: 95 J bivalve-1. Also, whereas A. monodon required on average 19 h to consume S. algosus, successful attacks on P. purpuratus required about 32% more time (25 h). In addition, a longer resting time was needed by the predator after preying on P. purpuratus before it initiated another attack. Moreover, the active metabolic costs associated with successfully attacking the prey increased 3.2 times over the basal metabolic costs when attacking S. algosus, but only by 2.5 times when attacking P. purpuratus. The calculations associated with preying on each species showed that the energetic gain per unit time likely accounts for the predator's preference for attacking S. algosus, even though predation on both species provided net energy gains for the predator. However, as S. algosus occurs seasonally at our study site, P. purpuratus would probably also be consumed due to its constant availability throughout the whole year.
Women with type 2 diabetes are disproportionally affected by macrovascular complications; we here investigated whether this is also the case for microvascular complications and retinal microvascular ...measures.
In a population-based cohort study of individuals aged 40-75 years (n = 3410; 49% women, 29% type 2 diabetes (oversampled by design)), we estimated sex-specific associations, and differences therein, of (pre)diabetes (reference: normal glucose metabolism), and of continuous measures of glycemia with microvascular complications and retinal measures (nephropathy, sensory neuropathy, and retinal arteriolar and venular diameters and dilatation). Sex differences were analyzed using regression models with interaction terms (i.e. sex-by- (pre)diabetes and sex-by-glycemia) and were adjusted for potential confounders.
Men with type 2 diabetes (but not those with prediabetes) compared to men with normal glucose metabolism, (and men with higher levels of glycemia), had significantly higher prevalences of nephropathy (odds ratio: 1.58 95% CI (1.01;2.46)) and sensory neuropathy (odds ratio: 2.46 (1.67;3.63)), larger retinal arteriolar diameters (difference: 4.29 µm (1.22;7.36)) and less retinal arteriolar dilatation (difference: - 0.74% (- 1.22; - 0.25)). In women, these associations were numerically in the same direction, but generally not statistically significant (odds ratios: 1.71 (0.90;3.25) and 1.22 (0.75;1.98); differences: 0.29 µm (- 3.50;4.07) and: - 0.52% (- 1.11;0.08), respectively). Interaction analyses revealed no consistent pattern of sex differences in the associations of either prediabetes or type 2 diabetes or glycemia with microvascular complications or retinal measures. The prevalence of advanced-stage complications was too low for evaluation.
Our findings show that women with type 2 diabetes are not disproportionately affected by early microvascular complications.
A combined study for understanding the molecular interactions of asphaltenes with molecular species such as ionic liquids (ILs) comprised experimental measurements and computational numerical ...simulation calculations, using density-functional theory (DFT) with dispersion corrections, molecular dynamics (MD) calculations, and experimental rheological characterization of the heavy crude oils (HCOs), before and after doping with ILs, respectively. The main results show that ILs influence the asphaltenic dimer association by forming supramolecular complexes that modify the properties of crude oils such as viscosity and interfacial tension. The IL–cation and asphaltene−π ligand molecular interactions seem to dominate the interactions between ionic liquids and asphaltenes, where ILs’ high aromaticity index induces a strong interaction with the aromatic hard core of asphaltenes.
PDF
