1,376 research outputs found
Influence of particle density on flow behavior and deposit architecture of concentrated pyroclastic density currents over a break in slope: Insights from laboratory experiments
Geological granular flows are highly complex, gravity-driven phenomena whose different behaviors depend on the mechanical properties, density and granulometric distributions of the constituent materials. Years of research have produced significant advances in understanding transport and deposition processes in granular flows. However, the role and effects of clast densities and density contrast in a granular flow are still not fully understood. In this paper we show the effect that pumice has on dry granular flows; specifically on flow velocity and longitudinal segregation of the deposits. Our work confirms, by experimental results, field observations on pumice/lithic segregation and longer pumice runout. We report results of velocity decay and deposit architecture for a granular flow passing over a break in slope (from 38° to 4° inclination). The 30 experimental runs were carried out in a five-meter long laboratory flume equipped with a series of sensors that include laser gates and high-speed cameras (400 fps). We used two polydisperse mixtures of dacitic lithics and rhyolitic pumice in varying amounts, with Weibull and Gaussian particle size distributions. The pumice/lithic ratio changes the flow response passing over a break in slope. This effect is particularly evident starting from 10% of pumice volume into the flow mixture, independently of its granulometric distribution. Runout relates to mass following a power law, with an exponent close 0.2. The experiments confirm that pumice segregation affects polydispersed mixtures, similarly to what has been observed in real field deposits, where density decoupling produces lithic-enriched proximal areas and pumice-enriched distal areas. The results obtained prove that the presence of low-density materials in a dense granular flow has a strong influence on its behavior
Spatial effects on species persistence and implications for biodiversity
Natural ecosystems are characterized by striking diversity of form and
functions and yet exhibit deep symmetries emerging across scales of space, time
and organizational complexity. Species-area relationships and species-abundance
distributions are examples of emerging patterns irrespective of the details of
the underlying ecosystem functions. Here we present empirical and theoretical
evidence for a new macroecological pattern related to the distributions of
local species persistence times, defined as the timespans between local
colonizations and extinctions in a given geographic region. Empirical
distributions pertaining to two different taxa, breeding birds and herbaceous
plants, analyzed in a new framework that accounts for the finiteness of the
observational period, exhibit power-law scaling limited by a cut-off determined
by the rate of emergence of new species. In spite of the differences between
taxa and spatial scales of analysis, the scaling exponents are statistically
indistinguishable from each other and significantly different from those
predicted by existing models. We theoretically investigate how the scaling
features depend on the structure of the spatial interaction network and show
that the empirical scaling exponents are reproduced once a two-dimensional
isotropic texture is used, regardless of the details of the ecological
interactions. The framework developed here also allows to link the cut-off
timescale with the spatial scale of analysis, and the persistence-time
distribution to the species-area relationship. We conclude that the inherent
coherence obtained between spatial and temporal macroecological patterns points
at a seemingly general feature of the dynamical evolution of ecosystems.Comment: 5 pages, 5 figures. Supplementary materials avaliable on
http://www.pnas.org/content/108/11/434
Machine-assisted Cyber Threat Analysis using Conceptual Knowledge Discovery
Over the last years, computer networks have evolved into highly dynamic and interconnected environments, involving multiple heterogeneous devices and providing a myriad of services on top of them. This complex landscape has made it extremely difficult for security administrators to keep accurate and be effective in protecting their systems against cyber threats. In this paper, we describe our vision and scientific posture on how artificial intelligence techniques and a smart use of security knowledge may assist system administrators in better defending their networks. To that end, we put forward a research roadmap involving three complimentary axes, namely, (I) the use of FCA-based mechanisms for managing configuration vulnerabilities, (II) the exploitation of knowledge representation techniques for automated security reasoning, and (III) the design of a cyber threat intelligence mechanism as a CKDD process. Then, we describe a machine-assisted process for cyber threat analysis which provides a holistic perspective of how these three research axes are integrated together
Quantification of impacts in artistic gymnastics with accelerometry: an approximation
Intensity and volume of training in Artisti Gymnastics are increasing as the sooner athlete's age of incorporation creating some disturbance in them
Protective effects of eicosapentaenoic acid plus hydroxytyrosol supplementation against white adipose tissue abnormalities in mice fed a high-fat diet
Objective: Obesity induced by high-fat diet (HFD) elicits white adipose tissue dysfunction. In this study, we have hypothesized that the metabolic modulator eicosapentaenoic acid (EPA) combined with the antioxidant hydroxytyrosol (HT) attenuates HFD-induced white adipose tissue (WAT) alterations. Methods: C57BL/6J mice were administered with a HFD (60% fat, 20% protein, 20% carbohydrates) or control diet (CD; 10% fat, 20% protein, 70% carbohydrates), with or without EPA (50 mg/kg/day), HT (5 mg/kg/day), or both for 12 weeks. Determinations in WAT include morphological parameters, EPA and docosahexaenoic acid content in phospholipids (gas chromatography), lipogenesis, oxidative stress (OS) and inflammation markers, and gene expression and activities of transcription factors, such as sterol regulatory element-binding protein-1c (SREBP-1c), peroxisome proliferator-activated receptor-gamma (PPAR-Îł), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ÎşB) (p65 subunit) and nuclear factor erythroid 2-related factor 2 (Nrf2) (quantitative polymerase chain reaction and enzyme linked immunosorbent assay). Results: HFD led to WAT hypertrophy in relation to PPAR-Îł downregulation. WAT metabolic dysfunction was characterized by upregulation of lipogenic SREBP-1c system, mitochondrial energy metabolism depression, loss of the antioxidant Nrf2 signaling with OS enhancement, n-3 long-chain polyunsaturated fatty acids depletion and activation of the pro-inflammatory NF-ÎşB system. EPA and HT co-supplementation diminished HFD-dependent effects additively, reaching values close or similar to controls. Conclusion: Data presented strengthen the importance of combined protocols such as EPA plus HT to attenuate metabolic-inflammatory states triggered by obesity
Potencial forrageiro de seis hĂbridos de sorgo com capim sudĂŁo.
Avaliaram-se quatro hĂbridos experimentais e duas cultivares comerciais de Sorghum bicolor cv bicolor x Sorghum bicolor cv sudanense quanto Ă s caracterĂsticas agronĂ´micas: produções de matĂ©ria verde por hectare (MV/ha), matĂ©ria seca (MS/ha), altura das plantas, nĂşmero de plantas/ha, taxa de rebrota e relação folha/haste. Os plantios ocorreram na transição do perĂodo seco para o perĂodo chuvoso. Os hĂbridos foram submetidos a trĂŞs cortes sucessivos, realizados em duas Ă©pocas de plantio. Foi empregado um delineamento experimental de blocos ao acaso e a comparação de mĂ©dias foi efetuada pelo teste de SNK, a 5% de probabilidade. Os hĂbridos estudados nĂŁo diferiram para a maioria das caracterĂsticas avaliadas, com exceção da população de plantas, em que o hĂbrido experimental ATF 54 x CMSXS 912, com 848 mil plantas/há, foi semelhante (P>0,05) aos hĂbridos testemunhas (comerciais) AG2501C, com 780 mil plantas/ha, e ao BRS800, com 749 mil plantas/ha, sendo superior (P<0,05) aos demais hĂbridos. Os resultados de produtividade indicam o potencial dos hĂbridos de sorgo com capim SudĂŁo estudados para serem utilizados como alternativa para a produção de forragem em regime de corte, na transição do perĂodo seco para o perĂodo chuvoso
Avaliação da silagem do hĂbrido de sorgo BR 601 com aditivos: alterações nos teores de matĂ©ria seca, frações fibrosas e digestibilidade "in vitro" da matĂ©ria seca.
Avaliou-se o padrĂŁo de fermentação de silagens do hĂbrido de sorgo forrageiro BR 601 com ou sem aditivos. Foram adotados os tratamentos: silagem sem aditivo (testemunha) e silagens adicionadas com 0,5% de urĂ©ia, 0,5% de carbonato de cálcio, 0,5% de urĂ©ia mais 0,5% de carbonato de cálcio e com inoculante bacteriano. Os materiais foram ensilados em silos de “PVC” e abertos com um, trĂŞs, cinco, sete, 14, 28 e 56 dias de ensilagem. Determinaram-se as variações nos teores de matĂ©ria seca (MS), os teores de fibra em detergente neutro (FDN), hemicelulose, celulose, fibra em detergente ácido (FDA), lignina e a digestibilidade “in vitro” da MS (DIVMS). Adotou-se o delineamento inteiramente casualizado, em um esquema fatorial 5 x 7, sendo as mĂ©dias comparadas pelo teste SNK a 5%. As silagens tratadas com a associação entre urĂ©ia e carbonato de cálcio apresentaram as maiores perdas de MS. Os aditivos nĂŁo promoveram alterações nos teores de FDN, hemicelulose e celulose e na DIVMS. Ocorreu diferença entre a silagem testemunha e as silagens com aditivo, com a evolução do processo fermentativo, quanto aos teores de FDA e lignina
Qualidade nutricional de seis hĂbridos de sorgo com capim sudĂŁo submetidos a Ă©pocas de plantio e cortes distintas.
Foram avaliados quatro hĂbridos experimentais (ATF 54 x CMSXS 912, CMSXS 156 x CMSXS 912, CMSXS 157 x CMSXS 912 e CMSXS 210 x CMSXS 912) e duas cultivares comerciais de Sorghum bicolor cv bicolor X Sorghum bicolor cv sudanense (AG2501C e BRS800) quanto ao valor nutritivo: produções de MS digestĂvel (MSD t/ha), digestibilidade in vitro da MS (DIVMS%), proteĂna bruta (PB%), fibra em detergente neutro (FDN%), fibra em detergente ácido (FDA%), fĂłsforo (P%) e cálcio (Ca%). Os hĂbridos foram submetidos a trĂŞs cortes sucessivos e o plantio foi realizado em duas Ă©pocas diferentes. O delineamento experimental foi o de blocos ao acaso e a comparação de mĂ©dias foi efetuada pelo teste de SNK, a 5% de probabilidade. Os hĂbridos ATF 54 x CMSXS 912 e AG 2501-C apresentaram valores mĂ©dios de produção 1,28 t de MSD/ha superiores nas duas Ă©pocas de plantio. Ocorreram diferenças entre os hĂbridos quanto aos teores de PB, com valor mĂ©dio de 16,33%, Ca com valores entre 0,42% e 0,49% e teores de P com valor mĂ©dio de 0,26%. O hĂbrido BRS 800 foi superior (p<0,05) quanto ao teor mĂ©dio de P (0,28%), teor mĂ©dio de PB (17,32%), sendo semelhante ao hĂbrido CMSXS 210 x CMSXS 912, que obteve o valor de 16,75%
Prognostic stratification improvement by integrating ID1/ID3/IGJ gene expression signature and immunophenotypic profile in adult patients with B-ALL
Characteristics of pronostic groups according to EuroFlow immunophenotype. (TIFF 1364 kb
Skin Bioimpedance Analysis to Determine Cellular Integrity by Phase Angle in Women with Fibromyalgia: A Cross-Sectional Study.
Oxidative stress has been proposed as a significant part of the pathogenesis of fibromyalgia,
and the phase angle in bioelectrical impedance analysis has been explored as a potential technique to
screen oxidative abnormalities. This study recruited 35 women with fibromyalgia and 35 healthy
women, who underwent bioelectrical impedance analysis and maximum isometric handgrip strength
tests. Women with fibromyalgia showed lower bilateral handgrip strength (right hand: 16.39 ± 5.87
vs. 27.53 ± 4.09, p < 0.001; left hand: 16.31 ± 5.51 vs. 27.61 ± 4.14, p < 0.001), as well as higher body
fat mass (27.14 ± 10.21 vs. 19.94 ± 7.25, p = 0.002), body fat percentage (37.80 ± 8.32 vs. 30.63 ± 7.77,
p < 0.001), and visceral fat area (136.76 ± 55.31 vs. 91.65 ± 42.04, p < 0.01) compared with healthy
women. There was no statistically significant difference in muscle mass between groups, but women
with fibromyalgia showed lower phase angles in all body regions when compared with healthy
control women (right arm: 4.42 ± 0.51 vs. 4.97 ± 0.48, p < 0.01; left arm: 4.23 ± 0.48 vs. 4.78 ± 0.50,
p < 0.001; trunk: 5.62 ± 0.77 vs. 6.78 ± 0.84, p < 0.001; right leg: 5.28 ± 0.56 vs. 5.81 ± 0.60, p < 0.001;
left leg: 5.07 ± 0.51 vs. 5.69 ± 0.58, p < 0.001; whole body: 4.81 ± 0.47 vs. 5.39 ± 0.49, p < 0.001).
Moreover, whole-body phase-angle reduction was only predicted by the presence of fibromyalgia
(R 2 = 0.264; β = 0.639; F(1,68) = 24.411; p < 0.001). Our study revealed significantly lower phase angle
values, lower handgrip strength, and higher fat levels in women with fibromyalgia compared to
healthy controls, which are data of clinical relevance when dealing with such patients.post-print1,25 M
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