Intimal and medial contributions to the hydraulic resistance of the arterial wall at different pressures: a combined computational and experimental study

The hydraulic resistances of the intima and media determine water flux and the advection of macromolecules into and across the arterial wall. Despite several experimental and computational studies, these transport processes and their dependence on transmural pressure remain incompletely understood. Here, we use a combination of experimental and computational methods to ascertain how the hydraulic permeability of the rat abdominal aorta depends on these two layers and how it is affected by structural rearrangement of the media under pressure. Ex vivo experiments determined the conductance of the whole wall, the thickness of the media and the geometry of medial smooth muscle cells (SMCs) and extracellular matrix (ECM). Numerical methods were used to compute water flux through the media. Intimal values were obtained by subtraction. A mechanism was identified that modulates pressure-induced changes in medial transport properties: compaction of the ECM leading to spatial reorganization of SMCs. This is summarized in an empirical constitutive law for permeability and volumetric strain. It led to the physiologically interesting observation that, as a consequence of the changes in medial microstructure, the relative contributions of the intima and media to the hydraulic resistance of the wall depend on the applied pressure; medial resistance dominated at pressures above approximately 93 mmHg in this vessel

Cosmological Constraints from Moments of the Thermal Sunyaev-Zel'dovich Effect

In this paper, we explain how moments of the thermal Sunyaev-Zel'dovich (tSZ) effect can constrain both cosmological parameters and the astrophysics of the intracluster medium (ICM). As the tSZ signal is strongly non-Gaussian, higher moments of tSZ maps contain useful information. We first calculate the dependence of the tSZ moments on cosmological parameters, finding that higher moments scale more steeply with sigma_8 and are sourced by more massive galaxy clusters. Taking advantage of the different dependence of the variance and skewness on cosmological and astrophysical parameters, we construct a statistic, ||/^1.4, which cancels much of the dependence on cosmology (i.e., sigma_8) yet remains sensitive to the astrophysics of intracluster gas (in particular, to the gas fraction in low-mass clusters). Constraining the ICM astrophysics using this statistic could break the well-known degeneracy between cosmology and gas physics in tSZ measurements, allowing for tight constraints on cosmological parameters. Although detailed simulations will be needed to fully characterize the accuracy of this technique, we provide a first application to data from the Atacama Cosmology Telescope and the South Pole Telescope. We estimate that a Planck-like full-sky tSZ map could achieve a <1% constraint on sigma_8 and a 1-sigma error on the sum of the neutrino masses that is comparable to the existing lower bound from oscillation measurements.Comment: 11 pages, 12 figures, to be submitted to Phys. Rev. D; v2: 14 pages, 16 figures, matches PRD accepted version (changes from v1 include additional calculations with primordial non-Gaussianity and a new appendix discussing the tSZ kurtosis

Categorizing Natural Language-Based Customer Satisfaction: An Implementation Method Using Support Vector Machine and Long Short-Term Memory Neural Network

Analyzing natural language-based Customer Satisfaction (CS) is a tedious process. This issue is practically true if one is to manually categorize large datasets. Fortunately, the advent of supervised machine learning techniques has paved the way toward the design of efficient categorization systems used for CS. This paper presents the feasibility of designing a text categorization model using two popular and robust algorithms – the Support Vector Machine (SVM) and Long Short-Term Memory (LSTM) Neural Network, in order to automatically categorize complaints, suggestions, feedbacks, and commendations. The study found that, in terms of training accuracy, SVM has best rating of 98.63% while LSTM has best rating of 99.32%. Such results mean that both SVM and LSTM algorithms are at par with each other in terms of training accuracy, but SVM is significantly faster than LSTM by approximately 35.47s. The training performance results of both algorithms are attributed on the limitations of the dataset size, high-dimensionality of both English and Tagalog languages, and applicability of the feature engineering techniques used. Interestingly, based on the results of actual implementation, both algorithms are found to be 100% effective in accurately predicting the correct CS categories. Hence, the extent of preference between the two algorithms boils down on the available dataset and the skill in optimizing these algorithms through feature engineering techniques and in implementing them toward actual text categorization applications

Nonglandular Trichomes of Californian and Hawaiian Tarweeds

The purpose of this paper was to demonstrate the diversity in nonglandular trichome morphology of tarweeds at the ultrastructural level, and to propose categories for the morphologies reported for such trichomes. Using light and scanning electron microscopy (SEM), the authors surveyed 31 species of II genera of tarweeds from California and three genera of tarweeds from Hawaii. Trichome cell wall thickness in the Californian species ranged from 1 to 6 ~μm, whereas in the Hawaiian species trichome cell wall thickness ranged from 1 to 14 ~μm. Based on their surface appearance using SEM, trichomes were grouped into four categories: grooved; smooth + grooved; smooth; and verrucose. The verrucose surface of trichomes is an innate feature of the cell wall and is not due to resinlike deposits. The ecology and growth form of the plants in each group were compared to the trichome surface structure. Ecologically, members of the grooved group were alike in experiencing prolonged exposure to solar irradiation; eight of the nine plants in this group are perennial. The smooth + grooved group of trichomes was found on tarweeds that inhabit various types of habitats. This is likely a transitional group. The smooth trichome group is composed of mostly low-elevation Californian annuals. No Hawaiian tarweed surveyed had completely smooth trichomes. Tarweeds having verrucose-surfaced trichomes were mostly found in regions of moderate moisture. The trichomes observed in Dubautia platyphylla were unique and could not be placed into any of the four groups; the surface of these trichomes was a combination of verrucose and smooth

Wood Anatomy of Myoporaceae: Ecological and Systematic Considerations

Quantitative and qualitative features are presented for 28 collections of three genera (Bontia, Eremophila, Myoporum); data on Oftia are also included since it is sometimes referred to Myoporaceae. Wood of all Myoporaceae represents variation on a basic plan: woods diffuse porous or semi-ringporous; vessels with simple perforation plates; lateral wall pits of vessels alternate and circular, with grooves interconnecting some pit apertures; vessels grouped to various degrees into radial multiples; imperforate tracheary elements all fiber-tracheids with pit cavities 1-5 μm in diameter (wider on contacts with ray cells), nonseptate; axial parenchyma vasicentric scanty plus, in some species, tangential para tracheal bands (sometimes terminal); rays multi seriate plus uniseriate (uniseriate almost exclusively in two species of Eremophila); ray cells procumbent exclusively, upright and square in uniseriate rays and in tips of multiseriate rays; rays storied in some species of Eremophila, axial parenchyma variously storied; crystals present in ray cells of some species of Eremophila and in fibers of E. polyclada; amorphous deposits and starch often present in parenchyma. Ofiia differs from Myoporaceae by having: septate libriform fibers rather than fiber-tracheids; large pits on vessel walls; axial parenchyma nearly absent; and erect cells predominant in rays. Oftia may be placed in Scrophulariaceae. Leucophyllum differs from Myoporaceae by having: helical thickenings in vessels; vasicentric tracheids transitional from vascular tracheids; scarce axial parenchyma; and erect cells predominant in rays. Leucophyllum may be excluded from Myoporaceae. Wood anatomy ofMyoporaceae shows relationship between Myoporaceae, Scrophulariaceae, and Gesneriaceae, and is also indicative of derivation from woody ancestors. Wood of Myoporaceae reflects xeromorphy, especially in Eremophila, but the foliar apparatus may partially preempt the role of wood in promoting safety, which is connoted by growth rings, narrow and numerous vessels, and grouped vessels

Wood and Stem Anatomy of Convolvulaceae

Quantitative and qualitative features of wood and stem anatomy are presented for 44 collections of 16 genera and 35 species ofConvolvulaceae. Markedly furrowed xylem characterizes the genera of tribe Cresseae. Successive cambia occur in 11 of the genera studied. Large patches of axial parenchyma occur in many of these; only in one species was interxylary phloem (formed internally by the cambium) observed in the parenchyma patches. Intraxylary phloem at the periphery of the pith is universal in Convolvulaceae, but newly reported is the fact that in many species, cambial activity adds secondary phloem to the intraxylary phloem strands. These cambia were also observed to add limited amounts of secondary xylem externally in Ericybe and Operculina. Fragmentation of the vascular cylinder by growth from the inner cambia leads to initiation of radially oriented cambia (ray cambia) along the ray zone where fracture occurs. Three new types of vessel restriction patterns (nonrandom distribution of vessels in wood or absence of vessels within some parts of the secondary xylem) are reported for the family (and dicotyledons). Rays are predominantly uniseriate; ray histology and quantitative vessel features show little change ontogenetically in species with successive cambia, suggesting that this cambial mode deters the kinds of progressive changes that occur in dicotyledons with a single cambium. Vessels are much wider in lianoid Convolvulaceae than in shrubby species; the lianoid species of Ipomoea have vessels twice the diameter of those in arborescent species of Ipomoea. Conjunctive parenchyma may serve for water storage in I. arborescens and other species, but this tissue and abundance of axial parenchyma in lianas might also aid flexibility and damage resistance. Septate fiber-tracheids and septate libriform fibers occur in a few species and represent tracheid dimorphism. Occurrence of tracheids together with fibriform vessel elements in woods of many Convolvulaceae suggests relationship of Convolvulaceae to Polemoniaceae and Hydrophyllaceae; intraxylary phloem and other wood features suggest relationship between Convolvulaceae and Solanaceae