894 research outputs found
A Liquid Extraction Column With Reciprocated Wire Mesh Packing
In a new type of pulsating, liquid extractor, pulsating energy is added to the counter currently flowing liquid streams by a stainless-steel wire mesh packing which is reciprocated vertically in a 3-inch i.d. extraction column. The mass transfer performance and flooding characteristics are studied as a function of the frequency and amplitude of reciprocation, the total solvent and feed throughputs, and choice of phase dispersion. The benzene-HAc-H2O and MIBK-HAcH2O systems were used. Extraction data for the benzene system were correlated in terms of a dimensionless pulse velocity group. Operating throughputs are significantly higher than those achieved with other designs of mechanically aided extractors, while maintaining high rates of extraction. © 1969, American Chemical Society. All rights reserved
Dimension fitting of wheat spikes in dense 3D point clouds based on the adaptive k-means algorithm with dynamic perspectives
The use of dense 3D point clouds to obtain agricultural crop dimensions in the place of manual measurement is crucial for enabling high-throughput phenotyping. To achieve this goal, this paper proposes an adaptive k-means algorithm based on dynamic perspectives, which first performs segmentation in order to separate the wheat spikes. We also propose a method to fit the shape of each spike and measures the dimensions of each spike with the help of the Random Sample Consensus algorithm. The experimental results show that the proposed method can be applied in a complex environment where multiple wheat spikes are grown densely and that it can fit the size of most wheat spikes accurately
Structural changes to the brood pouch of male pregnant seahorses (Hippocampus abdominalis) facilitate exchange between father and embryos
Introduction Embryonic growth and development require efficient respiratory gas exchange. Internal incubation of developing young thus presents a significant physiological challenge, because respiratory gas diffusion to embryos is impeded by the additional barrier of parental tissue between the embryo and the environment. Therefore, live-bearing species exhibit a variety of adaptations facilitating respiratory gas exchange between the parent (usually the mother) and embryos. Syngnathid fishes are the only vertebrates to exhibit male pregnancy, allowing comparative studies of the biology and evolution of internal incubation of embryos, independent of the female reproductive tract. Here, we examine the fleshy, sealed, seahorse brood pouch, and provide the first quantification of structural changes to this gestational organ across pregnancy. Methods We used histological analysis and morphometrics to quantify the surface area for exchange across the brood pouch epithelium, and the structure of the vascular bed of the brood pouch. Results We show dramatic remodelling of gestational tissues as pregnancy progresses, including an increase in tortuosity of the gestational epithelium, an increase in capillary density, and a decrease in diffusion distance between capillaries and the pouch lumen. Discussion These changes produce an increased surface area and expansion of the vascular bed of the placenta that likely facilitates respiratory gas exchange. These changes mirror the remodelling of gestational tissue in viviparous amniotes and elasmobranchs, and provide further evidence of the convergence of adaptations to support pregnancy in live-bearing animals
Solar dynamo models with alpha-effect and turbulent pumping from local 3D convection calculations
(abridged) Results from kinematic solar dynamo models employing alpha-effect
and turbulent pumping from local convection calculations are presented. We
estimate the magnitude of these effects to be around 2-3 m/s. The rotation
profile of the Sun as obtained from helioseismology is applied. We obtain an
estimate of the ratio of the two induction effects, C_alpha/C_Omega \approx
10^-3, which we keep fixed in all models. We also include a one-cell meridional
circulation pattern having a magnitude of 10-20 m/s near the surface and 1-2
m/s at the bottom of the convection zone. The model essentially represents a
distributed turbulent dynamo, as the alpha-effect is nonzero throughout the
convection zone, although it concentrates near the bottom of the convection
zone obtaining a maximum around 30 degrees of latitude. Turbulent pumping of
the mean fields is predominantly down- and equatorward. We find that, when all
these effects are included in the model, it is possible to correctly reproduce
many features of the solar activity cycle, namely the correct equatorward
migration at low latitudes and the polar branch at high latitudes, and the
observed negative sign of B_r B_phi. Although the activity clearly shifts
towards the equator in comparison to previous models due to the combined action
of the alpha-effect peaking at midlatitudes, meridional circulation and
latitudinal pumping, most of the activity still occurs at too high latitudes
(between 5-60 degrees). Other problems include the relatively narrow parameter
space within which the preferred solution is dipolar (A0), and the somewhat too
short cycle lengths of the solar-type solutions. The role of the surface shear
layer is found to be important only in the case where the alpha-effect has an
appreciable magnitude near the surface.Comment: 11 pages, 12 figures, accepted for publication in Astronomische
Nachrichte
An exactly solved model for mutation, recombination and selection
It is well known that rather general mutation-recombination models can be
solved algorithmically (though not in closed form) by means of Haldane
linearization. The price to be paid is that one has to work with a multiple
tensor product of the state space one started from.
Here, we present a relevant subclass of such models, in continuous time, with
independent mutation events at the sites, and crossover events between them. It
admits a closed solution of the corresponding differential equation on the
basis of the original state space, and also closed expressions for the linkage
disequilibria, derived by means of M\"obius inversion. As an extra benefit, the
approach can be extended to a model with selection of additive type across
sites. We also derive a necessary and sufficient criterion for the mean fitness
to be a Lyapunov function and determine the asymptotic behaviour of the
solutions.Comment: 48 page
Subaru and Gemini High Spatial Resolution Infrared 18 Micron Imaging Observations of Nearby Luminous Infrared Galaxies
We present the results of a ground-based, high spatial resolution infrared 18
micron imaging study of nearby luminous infrared galaxies (LIRGs), using the
Subaru 8.2-m and Gemini South 8.1-m telescopes. The diffraction-limited images
routinely achieved with these telescopes in the Q-band (17-23 micron) allow us
to investigate the detailed spatial distribution of infrared emission in these
LIRGs. We then investigate whether the emission surface brightnesses are
modest, as observed in starbursts, or are so high that luminous active galactic
nuclei (AGNs; high emission surface brightness energy sources) are indicated.
The sample consists of 18 luminous buried AGN candidates and
starburst-classified LIRGs identified in earlier infrared spectroscopy. We find
that the infrared 18 micron emission from the buried AGN candidates is
generally compact, and the estimated emission surface brightnesses are high,
sometimes exceeding the maximum value observed in and theoretically predicted
for a starburst phenomenon. The starburst-classified LIRGs usually display
spatially extended 18 micron emission and the estimated emission surface
brightnesses are modest, within the range sustained by a starburst phenomenon.
The general agreement between infrared spectroscopic and imaging energy
diagnostic methods suggests that both are useful tools for understanding the
hidden energy sources of the dusty LIRG population.Comment: 17 pages, 3 figures, accepted for publication in AJ (No. 141, 2011
May issue). Higher resolution version is available at
http://optik2.mtk.nao.ac.jp/~imanishi/Paper/20um/20um.pd
Seahorse brood pouch morphology and control of male parturition in Hippocampus abdominalis
Introduction Syngnathids (seahorses, pipefishes and seadragons) are among the few vertebrates that display male pregnancy. During seahorse pregnancy, males incubate developing embryos embedded in a placenta within a fleshy brood pouch, before expelling fully developed neonates at parturition. The mechanisms underpinning seahorse parturition are poorly understood. Methods We examined the morphology of the brood pouch using microcomputed tomography and histological techniques, in combination with physiological assays, to examine how male pot-bellied seahorses (Hippocampus abdominalis) control labour. In female-pregnant vertebrates, nonapeptide hormones (such as vasopressin- and oxytocin-like hormones) produce contractions of gestational smooth muscle to produce labour. Results Histological analysis of the seahorse brood pouch reveals only scattered small smooth muscle bundles in the brood pouch, and in-vitro application of isotocin (a teleost nonapeptide hormone) to the brood pouch do not produce measurable muscle contractions. Micro-computed tomography shows differences in size and orientation of the anal fin assembly between male and female pot-bellied seahorses, and histological analysis reveals large skeletal muscle bundles attached to the anal fin bones at the male brood pouch opening. Discussion We conclude that seahorse parturition may be facilitated by contraction of these muscles, which, in combination with body movements, serves to gape open the pouch and expel the neonates. Future biomechanical studies are needed to test this hypothesis
Patient-reported outcomes of pain and physical functioning in neurofibromatosis clinical trials.
ObjectiveTumors and other disease complications of neurofibromatosis (NF) can cause pain and negatively affect physical functioning. To document the clinical benefit of treatment in NF trials targeting these manifestations, patient-reported outcomes (PROs) assessing pain and physical functioning should be included as study endpoints. Currently, there is no consensus on the selection and use of such measures in the NF population. This article presents the recommendations of the PRO group of the Response Evaluation in Neurofibromatosis and Schwannomatosis (REiNS) International Collaboration for assessing the domains of pain and physical functioning for NF clinical trials.MethodsThe REiNS PRO group reviewed and rated existing PRO measures assessing pain intensity, pain interference, and physical functioning using their systematic method. Final recommendations are based primarily on 4 main criteria: patient characteristics, item content, psychometric properties, and feasibility for clinical trials.ResultsThe REiNS PRO group chose the Numeric Rating Scale-11 (≥8 years) to assess pain intensity, the Pain Interference Index (6-24 years) and the Patient-Reported Outcome Measurement Information System (PROMIS) Pain Interference Scale (≥18 years) to evaluate pain interference, and the PROMIS Physical Functioning Scale to measure upper extremity function and mobility (≥5 years) for NF clinical trials.ConclusionsThe REiNS Collaboration currently recommends these PRO measures to assess the domains of pain and physical functioning for NF clinical trials; however, further research is needed to evaluate their use in individuals with NF. A final consensus recommendation for the pain interference measure will be disseminated in a future publication based on findings from additional published research
Spitzer/IRS 5-35 um Low-Resolution Spectroscopy of the 12 um Seyfert Sample
We present low-resolution 5.5-35 um spectra for 103 galaxies from the 12 um
Seyfert sample, a complete unbiased 12 um flux limited sample of local Seyfert
galaxies selected from the IRAS Faint Source Catalog, obtained with the
Infrared Spectrograph (IRS) on-board Spitzer Space Telescope. For 70 of the
sources observed in the IRS mapping mode, uniformly extracted nuclear spectra
are presented for the first time. We performed an analysis of the continuum
emission, the strength of the Polycyclic Aromatic Hydrocarbon (PAH) and
astronomical silicate features of the sources. We find that on average, the
15-30 um slope of the continuum is alpha_{15-30}=-0.85+-0.61 for Seyfert 1s and
-1.53+-0.84 for Seyfert 2s, and there is substantial scatter in each type.
Moreover, nearly 32% of Seyfert 1s, and 9% of Seyfert 2s, display a peak in the
mid-infrared spectrum at 20 um, which is attributed to an additional hot dust
component. The PAH equivalent width decreases with increasing dust temperature,
asindicated by the global infrared color of the host galaxies. However, no
statistical difference in PAH equivalent width is detected between the two
Seyfert types, 1 and 2, of the same bolometric luminosity. The silicate
features at 9.7 and 18um in Seyfert 1 galaxies are rather weak, while Seyfert
2s are more likely to display strong silicate absorption. Those Seyfert 2s with
the highest silicate absorption also have high infrared luminosity and high
absorption (hydrogen column density N_H>10^23 cm^-2 as measured from the
X-rays. Finally, we propose a new method to estimate the AGN contribution to
the integrated 12 um galaxy emission, by subtracting the "star formation"
component in the Seyfert galaxies, making use of the tight correlation between
PAH 11.2 um luminosity and 12 um luminosity for star forming galaxies.Comment: accepted for publication in Ap
Reinventing ‘Towel City USA’: Textiles, Tourism and the Future of the Southeastern Mill Town
Throughout the southeastern region of the United States it is common to find towns that were built by textile companies in the late 19th century with the express purpose of manufacturing textile products. Textile companies sought rural areas within this region to build factories and then surrounded the factories with homes, schools, and stores designed to attract and keep workers (Suggs, 2002)
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