Miracle-dz/UniFAR-FTUs huggingface dataset:
Quantitative cerebral blood flow measurement with dynamic perfusion CT using the vascular-pixel elimination method: comparison with H2(15)O positron emission tomography.

BACKGROUND AND PURPOSE Blood vessels are usually conspicuous on dynamic CT perfusion images. The presence of large vessels may lead to overestimation of the quantitative value of cerebral blood flow (CBF). We evaluated the efficacy of the vascular-pixel elimination (VPE) method in quantitative CT perfusion imaging, in comparison with positron emission tomography (PET). METHODS Five healthy volunteers underwent CT perfusion and PET studies. A four-channel multi-detector row CT scanner was used. Dynamic cine scanning was performed after bolus injection of an intravenous contrast agent. CT-CBF was calculated by the central volume principle and deconvolution method. PET was performed after infusion of (15)O-labeled water. PET-CBF was calculated by using a nonlinear least squares method. Average CBF values of the whole section, gray matter, and white matter with both CT and PET were compared after image registration. The comparison was performed with and without VPE. In the VPE method, the vascular pixels were defined by the cerebral blood volume value of the pixel. The threshold of VPE was changed from 5 to 20 mL/100 g. Pixel-by-pixel correlation between CT-CBF and PET-CBF and linear regression analysis were also performed. RESULTS Without VPE, CT-CBF was overestimated in all subjects. As the VPE threshold decreased, CT-CBF decreased and the correlation coefficient increased. The best correlation was observed at a VPE threshold of 8 mL/100 g in four of the five subjects. Average CT-CBF values, without VPE, of the whole section, gray matter, and white matter were 59.01, 66.73, and 42.53 mL/100 g/min, respectively. With VPE (threshold, 8 mL/100 g), average CT-CBF values of the whole section, gray matter, and white matter were 45.56, 52.75, and 30.38, respectively. The corresponding PET-CBF values were 46.86, 50.89, and 38.20 mL/100 g/min, respectively. CONCLUSION Vascular pixels should be excluded from the calculation of CT-CBF to avoid overestimation of the CBF values. If vascular pixels are excluded, CBF calculation with CT perfusion imaging is considerably accurate.
Chemical Equilibrium in Hydrothermal Systems: The Case of Los Azufres Geothermal Field, Mexico

This work presents a review of the geological, hydrogeochemical, and mineralogical information related to the Los Azufres geothermal field, along with new isotopic data from hydrothermal calcite and quartz. The equilibrium state between present-day geothermal fluids and hydrothermal mineral phases in this field was examined using mineralogical, thermochemical, as well as isotopic data. Hydrothermal minerals in Los Azufres are typical for neutral to alkaline, high-temperature thermal fluids, forming an incipient to complete propylitic alteration of the primary rocks. The comparison of activity diagrams of common hydrothermal phases to mineralogical observations at Los Azufres shows that the reservoir rocks tend to approach a state of chemical equilibrium with hydrothermal fluids percolating through them. This tendency to equilibrium has been corroborated by analysis of the oxygen isotopic composition of hydrothermal calcite, whose σ18O values are in equilibrium with present geothermal or meteoric waters. Although 18O/16O ratios from some hydrothermal quartz samples show equilibrium with present-day fluids, others indicate the presence of fluids with higher 18O/16O ratios than modern geothermal water. The oxygen isotopic composition of hydrothermal quartz can thus be used as an indicator of isotopic compositions of fluids at the time of quartz precipitation.
Modelling gravity-driven flow over uneven surfaces

This study concerns the gravity-driven two-dimensional laminar flow of a thin layer of fluid down a wavy inclined surface. Three mathematical models describing the unsteady two-dimensional flow evolution are presented and contrasted. The first is a shallow-water model, while the other two are integral-boundarylayer models representing non-hydrostatic approximations to the two-dimensional Navier-Stokes equations, which are valid for thin fluid layers. Various tests and simulations were conducted in order to assess the performance of the models. First, the instability threshold for the flat bottom case associated with each model was analytically determined and compared with the theoretical prediction based on the Navier-Stokes equations. Also for the flat bottom case, comparisons in neutral stability curves were made with existing experimental data. In addition, comparisons between two-dimensional numerical solutions of the full Navier-Stokes equations, obtained using the CFX software package, with simulations from the models were also investigated for a wavy bottom case. The wavy surface considered in this study corresponds to that of a sinusoidal profile. The emerging interfacial wave structure along with the combined effect of bottom topography and surface tension are discussed. Finally, critical Reynolds number predictions for cases including bottom topography are compared to existing experimental data.
Treatment of multidrug-resistant Gram-negative infections in children.

Antibiotic resistance in conjunction with the erosion of the drug development pipeline may lead us into a bleak future, a "post-antibiotic era. " Because of a shortage of studies addressing treatment options for multidrug-resistant Gram-negative (MDRGN) infections in children, data must be extrapolated from the adult literature. However, even adult studies are limited by significant methodological flaws. We are in urgent need of pediatric specific pharmacokinetic/pharmacodynamic data for agents with activity against MDRGN infections as well as improved clinical outcomes studies. For the time being, we must rely on in vitro studies, observational data, and clinical experience to guide our therapeutic decisions. In this review, we discuss treatment considerations for infections caused by extended-spectrum β-lactamase-producing organisms, AmpC β-lactamase-producing organisms, carbapenem-resistant Enterobacteriaceae, carbapenem-resistant Pseudomonas aeruginosa, and carbapenem-resistant Acinetobacter baumannii in the pediatric population.
Multivariate analysis of the blood pressure variability in Bedouin tribes of South Sinai

Objective: to study intertribal and age-related variability of blood pressure values relative to the body mass index (hereinafter – BMI) in Bedouin tribes of the South Sinai using variance analysis and canonical discriminant analysis. Materials and methods. The samples based on physiological parameters (systolic and diastolic pressure, pulse pressure, and grip strength of the right and left hands) included 304 male and 68 female adults of Gebeliya, Muzeina, and Hamada tribes, and a combined group of representatives of various small tribes referred to as “Others”. Body length, body weight, grip strength of the right and the left hands of 482 adult males and 96 adult females were studied. Results. The studied Bedouin group, with its reduced weight and height values, stands out against the homogenous Middle East background. The performed variance analysis for the male sample revealed significant (p<0.05) intertribal differences in such parameters as grip strength of the right and the left hands, diastolic pressure, pulse pressure, and BMI. The increased hypertension rate was found in the age cohort of 19–29, probably due to their increased exposure to the stress associated with the ongoing social changes. According to the canonical discriminant analysis of the male sample, the Wilks’ lambda value was 0.72, and the intergroup variability was comparable to the intragroup variability. Conclusions. The problem of obesity is non-existent in the Bedouins residing in the South of Sinai. In the South Sinai Bedouin group, no significant correlation was revealed between the blood pressure and body mass index values. This fact is accounted for by the emaciation of the population. The authors tend to explain the low pulse pressure value in men (39.2 mm Hg) by the increased peripheral vascular resistance. With the significant degree of transgression in the tribal population, the canonical discriminant analysis showed a minor incongruity in the first canonical variable. The result of the multivariate study of physiological parameters is consistent with our primary hypothesis on the ambiguity of intertribal differences in the groups living under similar environmental conditions. While not denying the existence of some individual mosaic distinctions in the Bedouin tribes, the results of the performed multivariate analysis prove the intertribal differences in the current set of physiological parameters to be insignificant.
Higgsino Dark Matter Confronts 14 years of Fermi Gamma Ray Data

Thermal higgsino dark matter (DM), with mass around 1 TeV, is a well-motivated, minimal DM scenario that arises in supersymmetric extensions of the Standard Model. Higgsinos may naturally be the lightest superpartners in Split-supersymmetry models that decouple the scalar superpartners while keeping higgsinos and gauginos close to the TeV scale. Higgsino DM may annihilate today to give continuum gamma-ray emission at energies less than a TeV in addition to a line-like signature at energies equal to the mass. Previous searches for higgsino DM, for example with the H.E. S.S. gamma-ray telescope, have not reached the necessary sensitivity to probe the higgsino annihilation cross-section. In this work we make use of 14 years of Fermi gamma-ray data at energies above ∼ 10 GeV to search for the continuum emission near the Galactic Center from higgsino annihilation. We interpret our results using DM proﬁles from Milky Way analogue galaxies in the FIRE-2 hydrodynamic cosmological simulations. We set the strongest constraints to-date on higgsino-like DM. Our results show a mild, ∼ 2 σ preference for higgsino DM with a mass near the thermal higgsino mass and, depending on the DM density proﬁle, the expected cross-section.
The soils of the lower eastern slopes of the Cameroon mountain and their suitability for various perennial crops

On the eastern slopes of the Cameroon Mountains soils occurring below the 100- metre contour were surveyed on a scale 1:25,000. Most soils are young marine clay soils used for growing bananas, oilpalms, cocoa, rubber and tea. At some places there are lava streams from the mountains. A more general soil survey was made of the younger and older volcanic soils above the 100-metre contour line and a map, scale 1 : 100,000, was produced. The relative age of the various volcanic deposits could be estimated after completing the study of the origin, genesis and distribution of marine soils, that cover volcanic deposits in the lower part of the plain. The discovery of beach walls at different levels formed as a result of differences in sea-levels and gradual rise of the land, helped to solve various soil problems. Most soils are K-deficient, especially young volcanic soils.
Cassini/CAPS observations of duskside tail dynamics at Saturn

Plasma properties of Saturn's premidnight tail region are surveyed using Cassini/Cassini Plasma Spectrometer (CAPS) ion observations from 2010. Only low‐latitude (|lat| < 6°) intervals in which the CAPS viewing was roughly symmetric inward and outward around the corotation direction are used. Our numerical moments algorithm returns nonzero ion density for 70% (999) of the intervals selected. Of these, 642 had detectable water‐group ion densities, and the remainder were dominantly, if not entirely, light ions. The derived plasma parameters are similar to those found in an earlier study for the postmidnight tail region, except that we find little evidence for the systematic outflows identified in that study, and we do find numerous significant inflow events. One such inflow is identified as a dipolarization event, the first reported plasma properties of such a structure at Saturn. A second, long‐lasting event may be evidence for the existence at times of a quasi‐steady reconnection region in the premidnight tail. The large majority of the plasma flows are found to be within 20° of the corotation direction, though with flow speeds significantly lower than full corotation. While the inflow events represent plausible evidence for internally driven mass loss in the premidnight region, the absence of significant outflow events suggests that in the region surveyed here, tail reconnection has not yet proceeded to involve lobe field lines, so the disconnected plasma continues its general motion in the corotation direction.
General Principles of Rhythmogenesis in Central Pattern Networks Nih Public Access Author Manuscript

The cellular and ionic mechanisms that generate the rhythm in central pattern generator (CPG) networks for simple movements are not well understood. Using vertebrate locomotion, respiration and mastication as exemplars, I describe four main principles of rhythmogenesis: (1) rhythmogenic ionic currents underlie all CPG networks, regardless of whether they are driven by a network pacemaker or an endogenous pacemaker neuron kernel; (2) fast synaptic transmission often evokes slow currents that can affect cycle frequency; (3) there are likely to be multiple and redundant mechanisms for rhythmogenesis in any essential CPG network; and (4) glial cells may participate in CPG network function. The neural basis for rhythmogenesis in simple behaviors has been studied for almost 100 years, yet we cannot identify with certainty the detailed mechanisms by which rhythmic behaviors are generated in any vertebrate system. Early studies focused on whether locomotor rhythms were generated by a chain of coupled reflexes that require sensory feedback, or by a central neural network. By now there is general agreement that for the major rhythmic behaviors (including locomotion, respiration, and mastication, the subjects of this book), there exist CPG networks within the central nervous system that are able to drive the basic rhythmic behavior in the complete absence of sensory feedback. This of course does not eliminate an important role for sensory feedback, which certainly affects cycle frequency and for some behaviors determines the timing of one phase of the behavior. Given the existence of CPGs, the question of rhythmogenesis can be rephrased to ask how these networks determine the timing of the rhythmic behavior. In this chapter, I focus on cellular and molecular mechanisms that could underlie rhythmogenesis in CPG networks, especially those that drive locomotion, respiration, and mastication. Neuronal or network oscillators? Two competing mechanisms have been proposed to underlie rhythmogenesis in central pattern generator (CPG) networks, often presented in an either/or manner: either rhythms are driven by endogenously oscillatory neurons which serve as " pacemaker neurons, " or rhythms are generated by the pattern of synaptic connections within the network, forming a " network pacemaker " mechanism. The central point of the " pacemaker neuron " hypothesis is that the CPG network contains neurons that, even when completely isolated from all
Upscaling Hydraulic Properties and Soil Water Flow Processes in Heterogeneous Soils: A Review

This review covers, in a comprehensive manner, the approaches available in the literature to upscale soil water processes and hydraulic parameters in the vadose zone. We distinguish two categories of upscaling methods: forward approaches requiring information about the spatial distribution of hydraulic parameters at a small scale, and inverse modeling approaches requiring information about the spatial and temporal variation of state variables at various scales, including so‐called “soft data”. Geostatistical and scaling approaches are crucial to upscale soil water processes and to derive large‐scale effective fluxes and parameters from small‐scale information. Upscaling approaches include stochastic perturbation methods, the scaleway approach, the stream‐tube approach, the aggregation concept, inverse modeling approaches, and data fusion. With all upscaling methods, the estimated effective parameters depend not only on the properties of the heterogeneous flow field but also on boundary conditions. The use of the Richards equation at the field and watershed scale is based more on pragmatism than on a sound physical basis. There are practically no data sets presently available that provide sufficient information to extensively validate existing upscaling approaches. Use of numerical case studies has therefore been most common. More recently and still under development, hydrogeophysical methods combined with ground‐based remote sensing techniques promise significant contributions toward providing high‐quality data sets. Finally, most of the upscaling literature in vadose zone research has dealt with bare soils or deep vadose zones. There is a need to develop upscaling methods for real world soils, considering root water uptake mechanisms and other soil–plant–atmosphere interactions.
Drilling constraints on lithospheric accretion and evolution at Atlantis Massif, Mid‐Atlantic Ridge 30°N

Expeditions 304 and 305 of the Integrated Ocean Drilling Program cored and logged a 1.4 km section of the domal core of Atlantis Massif. Postdrilling research results summarized here constrain the structure and lithology of the Central Dome of this oceanic core complex. The dominantly gabbroic sequence recovered contrasts with predrilling predictions; application of the ground truth in subsequent geophysical processing has produced self-consistent models for the Central Dome. The presence of many thin interfingered petrologic units indicates that the intrusions forming the domal core were emplaced over a minimum of 100-220 kyr, and not as a single magma pulse. Isotopic and mineralogical alteration is intense in the upper 100 m but decreases in intensity with depth. Below 800 m, alteration is restricted to narrow zones surrounding faults, veins, igneous contacts, and to an interval of locally intense serpentinization in olivine-rich troctolite. Hydration of the lithosphere occurred over the complete range of temperature conditions from granulite to zeolite facies, but was predominantly in the amphibolite and greenschist range. Deformation of the sequence was remarkably localized, despite paleomagnetic indications that the dome has undergone at least 45 degrees rotation, presumably during unroofing via detachment faulting. Both the deformation pattern and the lithology contrast with what is known from seafloor studies on the adjacent Southern Ridge of the massif. There, the detachment capping the domal core deformed a 100 m thick zone and serpentinized peridotite comprises similar to 70% of recovered samples. We develop a working model of the evolution of Atlantis Massif over the past 2 Myr, outlining several stages that could explain the observed similarities and differences between the Central Dome and the Southern Ridge.
The role of synoptic‐scale circulation in the linkage between large‐scale ocean–atmosphere indices and winter surface climate in British Columbia, Canada

In much of North America, variables such as temperature, precipitation, snowpack and streamflow are modulated by modes of large‐scale ocean‐atmosphere variability such as the Pacific Decadal Oscillation (PDO), El Niño‐Southern Oscillation (ENSO) and the Pacific North American Pattern (PNA). In this study, we test the hypothesis that the influence of these modes on air temperature and precipitation in British Columbia (BC), Canada, can be explained in relation to changes in frequencies of synoptic‐scale circulation types. A catalogue of 13 circulation types was derived by classifying daily mean sea‐level pressure (MSLP) grids from 1948 to 2003. The grids cover BC and the North Pacific and were subjected to a standard pattern recognition algorithm employing principal component analysis followed by cluster analysis on the component scores. The circulation types are generally associated with distinctive patterns of precipitation and air temperature anomalies across BC. Multiple linear regressions for selected stations in BC using the type frequencies as predictors explain up to 75% of the variance of mean winter temperature and 65% of winter precipitation. The frequencies of most circulation types vary significantly between the different phases of ENSO, PDO and PNA in a manner consistent with the temperature anomalies associated with those modes and, to a lesser extent, with the more complex precipitation anomalies. In addition, however, average temperatures and precipitation amounts for some circulation types differ systematically between phases of ENSO and PDO. Subsequent analysis revealed distinct differences among ENSO and PDO phases in the upper‐level circulation patterns associated with some surface types. A major part of the teleconnections can be explained through variations in the frequencies of synoptic‐scale circulation types, but systematic within‐type variability, particularly with PDO and PNA, can additionally influence the surface climate. Copyright © 2005 Royal Meteorological Society.
Climate evolution in the Pliocene and Pleistocene from marine‐sediment records and simulations: Internal variability versus orbital forcing

Three deep sea δ18O records are compared in the temporal and spectral domain with each other, a simple ice sheet and bedrock climate model simulation and insolation anomalies at 65°N. The model is one-dimensional; it represents the accumulation and ablation processes of ice, its viscoplastic flow, and the isostatic adjustment of bedrock under it, being forced solely by orbital insolation anomalies. The objective of the comparison is to determine the importance of internal variability arising from feedback between the ice sheets and bedrock through the late Pliocene and Pleistocene in the simulations and in the climate record. It is found that a considerable part of the spectral variability at suborbital frequencies, i.e., below the precessional and obliquity frequencies, as seen in the sediment cores, is simulated by the model. Simulated variability near 100 kyr has its period determined by the difference between two precessional frequencies. The model's internal variability mechanism has a period near 30–50 kyr but is highly damped. Still, it enhances suborbital variability near 100 kyr and 300 kyr and appears to induce nonstationarity of the orbital and suborbital peaks on even longer time scales. Since the insolation forcing exhibits no noticeable peaks at suborbital or lower frequencies, it appears that the nonstationarity in the model simulations as well as the suborbital peaks themselves are due to coupling between model nonlinearities and the orbital forcing. Since the variability at 100 kyr in the deep sea records is correlated with the simulated variability, such a control by the orbital forcing may be also operating in the climate system. The absence from the simulation of a trend toward larger ice sheets and colder climate seen throughout the Pleistocene in the sediment record is possibly due to slow tectonics and CO2 forcing changes not included in the model.
Good Intentions: Providing Students with Skills to Avoid Accidental Plagiarism

This article explores one librarian's experience with creating and implementing a plagiarism seminar as part of the library liaison program to the School of Public Health and Health Professions at the University at Buffalo. The changes and evolution of the seminar over several iterations are described. This article also examines student perceptions, misperceptions, and reactions to the plagiarism workshop.