622 research outputs found
Machine Learning Classification of Traumatic Brain Injury Patients Versus Healthy Controls Using Arterial Spin Labeled Perfusion MRI
Traumatic brain injury (TBI) is one of the most common causes of death and disability worldwide, yet accurate in vivo detection of TBI neuropathology remains challenging due to complexities in the structural and functional changes observed post-injury as well as limitations in conventional neuroimaging modalities. Although advanced neuroimaging techniques such as arterial spin labeling (ASL) can noninvasively assess cerebral blood flow (CBF) changes observed post-injury, this technique is underutilized in TBI research partly due to the low signal-to-noise-ratio (SNR) inherent in ASL imaging. The aim of the current study is to examine the use of machine learning, specifically a Support Vector Machine (SVM) classifier, in discriminating between healthy controls (n=35) and TBI patients (n=42) using ASL-generated CBF data 3 months post-injury. Identification of the regions of interest (ROIs) most predictive of TBI is also explored as part of this aim. Furthermore, several ASL outlier cleaning methods, such as the Structural Correlation- Based Outlier REjection (SCORE) and prior-guided, slice-wise adaptive outlier cleaning (PAOCSL) algorithms, are examined in relation to improving the SNR and SVM performance. While the classification models tested did not reach statistically significant performance levels, the results were in the direction suggesting that more sophisticated outlier cleaning methods can improve classification accuracy. Potential explanations of the observed low classification accuracy and the implications of our findings on future research are discussed
Feminisms outraged at justice: the online conversation on La Manada case
Este artículo examina la conversación en Twitter surgida a raíz de la sentencia de “La
Manada”, poniendo en relación un poder público, el judicial, con uno de los movimientos
sociales más activos, el feminismo. Con este fin, se aplica una metodología de estudio
de caso sustentada en una aproximación empírica de Análisis de Redes Sociales útiles
para distinguir entre una indignación espontánea y otra estratégica, infiriendo que los
feminismos tienen aún muchas alianzas que explorar.This paper examines the online conversation on Twitter resulting from the court ruling in the
‘La Manada’ case, linking the judiciary to feminism, currently one of the most active social
movements. To this end, a case study methodological based on an empirical approach to
social network analysis was employed. Both of them are useful for distinguishing between
spontaneous and strategic indignation and, therefore, for inferring that feminisms still have
many alliances to explore
Noninvasive identification of carbon-based black pigments with pump-probe microscopy
Carbon-based black pigments, a widely used class of pigments, are difficult
to differentiate with the noninvasive techniques currently used in cultural
heritage science. We utilize pump-probe microscopy to distinguish four common
carbon-based black pigments as pure pigments, as two-component black pigment
mixtures, and as a mixture of a black and a colorful pigment. This work also
demonstrates that even nominally homogeneous pigments present remarkable, and
useful, heterogeneity in pump-probe microscopy
The impact of inter‐flood duration on non‐cohesive sediment bed stability
© 2019 John Wiley & Sons, Ltd. Limited field and flume data suggests that both uniform and graded beds appear to progressively stabilize when subjected to inter-flood flows as characterized by the absence of active bedload transport. Previous work has shown that the degree of bed stabilization scales with duration of inter-flood flow, however, the sensitivity of this response to bed surface grain size distribution has not been explored. This article presents the first detailed comparison of the dependence of graded bed stability on inter-flood flow duration. Sixty discrete experiments, including repetitions, were undertaken using three grain size distributions of identical D50 (4.8 mm); near-uniform (σg = 1.13), unimodal (σg = 1.63) and bimodal (σg = 2.08). Each bed was conditioned for between 0 (benchmark) and 960 minutes by an antecedent shear stress below the entrainment threshold of the bed (τ*c50). The degree of bed stabilization was determined by measuring changes to critical entrainment thresholds and bedload flux characteristics. Results show that (i) increasing inter-flood duration from 0 to 960 minutes increases the average threshold shear stress of the D50 by up to 18%; (ii) bedload transport rates were reduced by up to 90% as inter-flood duration increased from 0 to 960 minutes; (iii) the rate of response to changes in inter-flood duration in both critical shear stress and bedload transport rate is non-linear and is inversely proportional to antecedent duration; (iv) there is a grade dependent response to changes in critical shear stress where the magnitude of response in uniform beds is up to twice that of the graded beds; and (v) there is a grade dependent response to changes in bedload transport rate where the bimodal bed is most responsive in terms of the magnitude of change. These advances underpin the development of more accurate predictions of both entrainment thresholds and bedload flux timing and magnitude, as well as having implications for the management of environmental flow design. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd
Inflammatory Response and Toxicity After Pressurized IntraPeritoneal Aerosol Chemotherapy.
Background: Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) is a novel mode of intraperitoneal (IP) drug delivery claiming high IP tissue concentrations with low systemic uptake. The aim was to study inflammatory response and systemic toxicity after PIPAC. Methods: Retrospective monocentric analysis of a consecutive cohort of PIPAC patients between January 2015 and April 2016. Detailed hematological and biochemical analysis was performed the day before surgery and once daily until discharge. Comparative statistics were performed using Mann-Whitney U test and Wilcoxon signed ranked test. Results: Fourty-two consecutive patients underwent a total of 91 PIPAC procedures. Twenty patients received oxaliplatin and 22 cisplatin+doxorubicin (37 vs. 54 procedures). Creatinine, AST and ALT were not significantly altered after PIPAC (p=0.095, p= p=0.153 and p=0.351) and not different between oxaliplatin and cisplatin+doxorubicin regimens (p=0.371, p=0.251 and p=0.288). C-reactive protein (CRP) and procalcitonin (PCT) increased on post-operative day (POD) 2: ∆max 29±5 mg/L (p<0.001) and ∆max 0.05±0.01 μg/L (p=0.005), respectively. Leucocytes increased at POD 1: ∆max 2.2±0.3 G/L (p<0.001). Albumin decreased at POD 2: ∆max -6.0±0.5 g/L (p<0.001). CRP increase correlated positively with Peritoneal Cancer Index (tumor load) (ρ =0.521, p<0.001). Conclusion: PIPAC was followed by a modest and transitory inflammatory response that was commensurate to the disease extent. No hematological, renal or hepatic toxicity was observed even after repetitive administration
Direct Military Intervention and Stability in the United States' Backyard, 1965-1995
The United States foreign policy of stabilization through direct military intervention has stirred considerable controversy with regards to both its ethics and effectiveness, not least following the recent failures to stabilize the political systems of Afghanistan and Iraq in the aftermath of intervention. Putting normative questions aside, the focus of this work is to analyze the effectiveness of modern United States stabilization operations from a historical perspective by examining Central America and the Caribbean, the geopolitical region in which the United States has maintained its longest and most direct sphere of influence.La política exterior d'estabilització dels Estats Units mitjançant intervencions militars directes ha provocat una important controvèrsia en relació tant a la seva ètica com a la seva efectivitat, i més després dels recents fracassos, conseqüència de la intervenció, per estabilitzar els sistemes polítics d'Afganistan i Iraq. Deixant de banda qüestions normatives, el focus d'aquest treball és analitzar l'efectivitat de les operacions modernes d'estabilització dels Estats Units des d'una perspectiva històrica a través de l'estudi d'Amèrica Central i el Carib, regió geopolítica on els Estats Units ha mantingut la més llarga i més directa esfera d'influència
Self-similarity of Mean Flow in Pipe Turbulence
Based on our previous modified log-wake law in turbulent pipe ‡flows, we invent two compound similarity numbers (Y;U), where Y is a combination of the inner variable y+ and outer variable , and U is the pure exect of the wall. The two similarity numbers can well collapse mean velocity profile data with different moderate and large Reynolds numbers into a single universal profile. We then propose an arctangent law for the buffer layer and a general log law for the outer region in terms of (Y;U). From Milikan’s maximum velocity law and the Princeton superpipe data, we derive the von Kármán constant = 0:43 and the additive constant B=6. Using an asymptotic matching method, we obtain a self-similarity law that describes the mean velocity profile from the wall to axis; and embeds the linear law in the viscous sublayer, the quartic law in the bursting sublayer, the classic log law in the overlap, the sine-square wake law in the wake layer, and the parabolic law near the pipe axis. The proposed arctangent law, the general log law and the self-similarity law have been compared with the high-quality data sets, with diffrent Reynolds numbers, including those from the Princeton superpipe, Loulou et al., Durst et al., Perry et al., and den Toonder and Nieuwstadt. Finally, as an application of the proposed laws, we improve the McKeon et al. method for Pitot probe displacement correction, which can be used to correct the widely used Zagarola and Smits data set
An embedding scheme for the Dirac equation
An embedding scheme is developed for the Dirac Hamiltonian H. Dividing space
into regions I and II separated by surface S, an expression is derived for the
expectation value of H which makes explicit reference to a trial function
defined in I alone, with all details of region II replaced by an effective
potential acting on S and which is related to the Green function of region II.
Stationary solutions provide approximations to the eigenstates of H within I.
The Green function for the embedded Hamiltonian is equal to the Green function
for the entire system in region I. Application of the method is illustrated for
the problem of a hydrogen atom in a spherical cavity and an Au(001)/Ag/Au(001)
sandwich structure using basis sets that satisfy kinetic balance.Comment: 16 pages, 5 figure
Synergistic Antibacterial Effects of Metallic Nanoparticle Combinations
© The Author(s) 2019.Metallic nanoparticles have unique antimicrobial properties that make them suitable for use within medical and pharmaceutical devices to prevent the spread of infection in healthcare. The use of nanoparticles in healthcare is on the increase with silver being used in many devices. However, not all metallic nanoparticles can target and kill all disease-causing bacteria. To overcome this, a combination of several different metallic nanoparticles were used in this study to compare effects of multiple metallic nanoparticles when in combination than when used singly, as single elemental nanoparticles (SENPs), against two common hospital acquired pathogens (Staphylococcus aureus and Pseudomonas. aeruginosa). Flow cytometry LIVE/DEAD assay was used to determine rates of cell death within a bacterial population when exposed to the nanoparticles. Results were analysed using linear models to compare effectiveness of three different metallic nanoparticles, tungsten carbide (WC), silver (Ag) and copper (Cu), in combination and separately. Results show that when the nanoparticles are placed in combination (NPCs), antimicrobial effects significantly increase than when compared with SENPs (P < 0.01). This study demonstrates that certain metallic nanoparticles can be used in combination to improve the antimicrobial efficiency in destroying morphologically distinct pathogens within the healthcare and pharmaceutical industry.Peer reviewe
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