FAKE STAR FORMATION BURSTS: BLUE HORIZONTAL BRANCH STARS MASQUERADE AS YOUNG MASSIVE STARS IN OPTICAL INTEGRATED LIGHT SPECTROSCOPY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ocvirk, P.

2010-01-20

Model color-magnitude diagrams of low-metallicity globular clusters (GCs) usually show a deficit of hot evolved stars with respect to observations. We investigate quantitatively the impact of such modeling inaccuracies on the significance of star formation history reconstructions obtained from optical integrated spectra. To do so, we analyze the sample of spectra of galactic globular clusters of Schiavon et al. with STECKMAP (Ocvirk et al.), and the stellar population models of Vazdekis et al. and Bruzual and Charlot, and focus on the reconstructed stellar age distributions. First, we show that background/foreground contamination correlates with E(B - V), which allows us tomore » define a clean subsample of uncontaminated GCs, on the basis of an E(B - V) filtering. We then identify a 'confusion zone' where fake young bursts of star formation pop up in the star formation history although the observed population is genuinely old. These artifacts appear for 70%-100% of cases depending on the population model used, and contribute up to 12% of the light in the optical. Their correlation with the horizontal branch (HB) ratio indicates that the confusion is driven by HB morphology: red HB clusters are well fitted by old stellar population models while those with a blue HB require an additional hot component. The confusion zone extends over [Fe/H] = [ - 2, - 1.2], although we lack the data to probe extreme high and low metallicity regimes. As a consequence, any young starburst superimposed on an old stellar population in this metallicity range could be regarded as a modeling artifact, if it weighs less than 12% of the optical light, and if no emission lines typical of an H II region are present. This work also provides a practical method for constraining HB morphology from high signal to noise integrated light spectroscopy in the optical. This will allow post-asymptotic giant branch evolution studies in a range of environments and at distances where resolving stellar

The subdwarf B star SB 290 - A fast rotator on the extreme horizontal branch

NASA Astrophysics Data System (ADS)

Geier, S.; Heber, U.; Heuser, C.; Classen, L.; O'Toole, S. J.; Edelmann, H.

2013-03-01

Hot subdwarf B stars (sdBs) are evolved core helium-burning stars with very thin hydrogen envelopes. To form an sdB, the progenitor has to lose almost all of its hydrogen envelope right at the tip of the red giant branch. In close binary systems, mass transfer to the companion provides the extraordinary mass loss required for their formation. However, apparently single sdBs exist as well, and their formation has been unclear for decades. The merger of helium white dwarfs leading to an ignition of core helium-burning or the merger of a helium core and a low-mass star during the common envelope phase have been proposed. Here we report the discovery of SB 290 as the first apparently single, fast-rotating sdB star located on the extreme horizontal branch, indicating that those stars may form from mergers. Appendix A is available in electronic form at http://www.aanda.org

1969 - 2010: Multicolor Photometric Observations of Population II Field Horizontal-Branch Stars

NASA Astrophysics Data System (ADS)

Philip, A. G. Davis

2010-05-01

From 1969 to 2010 I have been involved in a photometric study of Population II Field Horizontal-Branch stars. I started by making Stromgren four-color observations at Kitt Peak National Observatory and then Cerro Tololo Inter-American Observatory. I had taken spectral plates of all my selected areas on which I marked all the A-type stars. These stars were then observed photometrically. New FHB stars could be identified by their large c1 indices, caused by their greater (u-b) colors. Later four new filters were added ( U V B S ). With Richard Boyle of the Vatican Observatory we observed on Mt. Graham (Arizona) on the Vatican Advanced Technology Telescope.We plan follow-up observations of the new FHB stars found.

1969 to 2010: Multicolor Photometric Observations of Population II Field Horizontal-Branch Stars

NASA Astrophysics Data System (ADS)

Philip, A. G. D.

2011-04-01

From 1969 to 2010 I have been involved in a photometric study of Population II Field Horizontal-Branch Stars and published several papers on this topic in BOTT from 1967 thru 1972. I started by making Strömgren four-color observations at Kitt Peak National Observatory and then at Cerro Tololo Inter-American Observatory. I had taken spectral plates of all my selected areas on which I marked all the A-type stars. These stars were then observed photometrically. New FHB stars could be identified by their large c indices, caused by their greater (u-b) colors. Later four new filters were added (U, V, B, S). With Richard Boyle of the Vatican Observatory we observed on Mt. Graham (Arizona) on the Vatican Advanced Technology Telescope. We are making follow-up observations of the new FHB stars found.

Pahoehoe toe dimensions, morphology, and branching relationships at Mauna Ulu, Kilauea Volcano, Hawai'i

NASA Astrophysics Data System (ADS)

Crown, David A.; Baloga, Stephen M.

Pahoehoe toe dimensions, morphology, and branching relationships were analyzed in flows emplaced during 1972 at Mauna Ulu, a satellitic shield on the east rift zone of Kilauea Volcano, Hawai'i. In order to characterize regions within flow fields dominated by networks of pahoehoe toes, measurements of toe length, width, thickness, and orientation were completed for 445 toes at 13 sites. Variations in site characteristics, including slope, substrate, and position in the flow field allow an evaluation of the effects of such parameters on toe dimensions. Toe surface morphology (ropy or smooth), local flow lobe position (interior or margin), and connective relationships between toes were documented in the form of detailed toe maps. These maps show the number of branches connecting a given toe to other toes in its local pahoehoe network and illustrate branching patterns. Statistical analyses of toe dimensions and comparisons of pahoehoe toe study sites and sub-populations combined with field observations, evaluation of toe maps, and qualitative examination of toe dimension size distributions show the following: (a) Although there are significant variations at a given site, toes typically have mean lengths (101cm) greater than mean widths (74cm) and mean widths greater than mean thicknesses (19cm) sites that have mean widths greater than mean lengths are those with lower slopes. (b) Where significant site-to-site variations in mean values of a given toe dimension were apparent, these differences could not be directly related to site characteristics. (c) Ropy toes have significantly larger mean values of length, width, and number of branches than smooth toes, and toes with three or more branches have greater lengths, widths, and thicknesses than toes with two or fewer branches, suggesting concentration of flow in these toe types. (d) The skewness of all size distributions of toe length and width to larger values suggests that toes are transitional to larger sheets and

Spatial Arrangement of Branches in Relation to Slope and Neighbourhood Competition

PubMed Central

SUMIDA, AKIHIRO; TERAZAWA, IKUE; TOGASHI, ASAKO; KOMIYAMA, AKIRA

2002-01-01

To gain a better understanding of the effects of spatial structure on patterns of neighbourhood competition among hardwood trees, the three‐dimensional extension of primary branches was surveyed for ten community‐grown Castanea crenata (Fagaceae) trees with respect to the positioning of neighbouring branches and the slope of the forest floor. There were significantly more branches extending towards the lower side of the slope than towards the upper side, but structural properties such as branch length and vertical angle were not affected by slope. When horizontal extension of a branch towards its neighbour was compared for a C. crenata branch and a neighbouring heterospecific, the former was significantly narrower than the latter when the inter‐branch distance (horizontal distance between the base positions of two neighbouring branches) was short (< approx. 5 m). Castanea crenata branches tended to extend in a direction avoiding neighbouring branches of heterospecifics when the inter‐branch distance was short. Furthermore, for an inter‐branch distance <3 m, the horizontal extension of a C. crenata branch was less when it was neighbouring a heterospecific branch than when neighbouring a conspecific branch. These results suggest that horizontal extension of C. crenata branches is more prone to spatial invasion by nearby neighbouring branches of heterospecifics, and that the invasion can be lessened when C. crenata trees are spatially aggregated. The reason why such an arrangement occurs is discussed in relation to the later leaf‐flush of C. crenata compared with that of other species in the forest. PMID:12096742

Melatonin Inhibits Embryonic Salivary Gland Branching Morphogenesis by Regulating Both Epithelial Cell Adhesion and Morphology

PubMed Central

Miura, Jiro; Sakai, Manabu; Uchida, Hitoshi; Nakamura, Wataru; Nohara, Kanji; Maruyama, Yusuke; Hattori, Atsuhiko; Sakai, Takayoshi

2015-01-01

Many organs, including salivary glands, lung, and kidney, are formed by epithelial branching during embryonic development. Branching morphogenesis occurs via either local outgrowths or the formation of clefts that subdivide epithelia into buds. This process is promoted by various factors, but the mechanism of branching morphogenesis is not fully understood. Here we have defined melatonin as a potential negative regulator or “brake” of branching morphogenesis, shown that the levels of it and its receptors decline when branching morphogenesis begins, and identified the process that it regulates. Melatonin has various physiological functions, including circadian rhythm regulation, free-radical scavenging, and gonadal development. Furthermore, melatonin is present in saliva and may have an important physiological role in the oral cavity. In this study, we found that the melatonin receptor is highly expressed on the acinar epithelium of the embryonic submandibular gland. We also found that exogenous melatonin reduces salivary gland size and inhibits branching morphogenesis. We suggest that this inhibition does not depend on changes in either proliferation or apoptosis, but rather relates to changes in epithelial cell adhesion and morphology. In summary, we have demonstrated a novel function of melatonin in organ formation during embryonic development. PMID:25876057

Constraints on Helium Enhancement in the Globular Cluster M3 (NGC 5272): The Horizontal Branch Test

NASA Technical Reports Server (NTRS)

Catelan, M.; Grundahl, F.; Sweigart, A. V.; Valcarce, A. A. R.; Cortes, C.

2007-01-01

It has recently been suggested that the presence of multiple populations showing various amounts of helium enhancement is a common feature among globular star clusters. In this scenario, such a helium enhancement would be particularly apparent in the enhanced luminosity of thc blue horizontal branch (HB) stars compared to the red HB stars. In this Letter, wc test this scenario in the case of the Galactic globular cluster M3 (NGC 5272), using high-precision Stromgren photometry and spectroscopic gravities for blue HB stars. We find that any helium enhancement among the cluster's blue HB stars must be significantly less than I%, thus ruling out the much higher helium enhancements that have been proposed in the literature.

A New Formation Mechanism for the Hottest Horizontal-Branch Stars

NASA Technical Reports Server (NTRS)

Sweigart, Allen V.; Oegerle, William R. (Technical Monitor)

2002-01-01

Hot subluminous stars lying up to 0.7 mag below the extreme horizontal branch (EHB) are found in the ultraviolet color-magnitude diagrams (CMDs) of both omega Cen and NGC 2808. In order to investigate the origin of these subluminous stars, we have constructed a detailed set of evolutionary sequences that follow the evolution of low-mass stars continuously from the zero-age main sequence through the helium-core flash to the HB for a wide range in the mass loss along the red-giant branch (RGB). Stars with the largest mass loss evolve off the RGB to high effective temperatures before igniting helium in their cores. Our results indicate that the subluminous EHB stars, as well as the high temperature gap along the EHB of NGC 2808, can be explained if these stars undergo a late helium-core flash while descending the white-dwarf cooling curve. Under these conditions the convection zone produced by the main helium flash will penetrate into the stellar envelope, thereby mixing most, if not all, of the envelope hydrogen into the hot helium-burning interior, where it is rapidly consumed. This phenomenon is analogous to the 'born-again' scenario for producing hydrogen-deficient stars following a very late helium-shell flash. This 'flash mixing' of the envelope during a late helium-core flash greatly enhances the envelope helium and carbon abundances and, as a result, leads to a discontinuous increase in the HB effective temperature. We argue that the hot HB gap observed in NGC 2808 is associated with this theoretically predicted dichotomy in the RB properties. Using new helium- and carbon-rich stellar atmospheres, we show that the changes in the envelope abundances due to flash mixing will suppress the ultraviolet flux in the spectra of hot EHB stars. We suggest that such changes in the emergent spectral energy distribution are primarily responsible for explaining the hot subluminous EHB stars in omega Cen and NGC 2808. Moreover, we demonstrate that models without flash mixing

Effect of PR interval prolongation on long-term outcomes in patients with left bundle branch block vs non-left bundle branch block morphologies undergoing cardiac resynchronization therapy.

PubMed

Rickard, John; Karim, Mohammad; Baranowski, Bryan; Cantillon, Daniel; Spragg, David; Tang, W H Wilson; Niebauer, Mark; Grimm, Richard; Trulock, Kevin; Wilkoff, Bruce; Varma, Niraj

2017-10-01

Although the influence of QRS duration (QRSd) and/or bundle branch block morphology on outcomes of cardiac resynchronization therapy (CRT) have been well studied, the effect of PR interval remains uncertain. The purpose of this study was to evaluate the impact of PR prolongation (PRp) before CRT on long-term outcomes, specifically taking into account bundle branch block morphology and QRSd. We extracted clinical data on consecutive patients undergoing CRT. Multivariate models were constructed to analyze the effect of PRp (≥200 ms) on the combined endpoint of death, heart transplant, or left ventricular assist device. Kaplan-Meier curves were constructed stratifying patients based on bundle branch block and QRSd (dichotomized by 150 ms). Of the 472 patients who met inclusion criteria, 197 (41.7%) had PR interval ≥200 ms. During follow-up (mean 5.1 ± 2.6 years) there were 214 endpoints, of which 109 (23.1%) occurred in patients with PRp. In multivariate analysis, PRp was independently associated with worsened outcomes (hazard ratio 1.34, 95% confidence interval 1.01-1.77, P = .04). When stratified by bundle branch block morphology, PRp was significantly associated with worsened outcomes (log-rank P <.001) in patients with LBBB but not in those with non-LBBB (log-rank P = .55). Among patients with LBBB, stratified by QRSd, patients without PRp had improved outcomes compared to those with PRp independent of QRSd (log-rank P <.001). PRp is an independent predictor of impaired long-term outcome after CRT among patients with LBBB but not in non-LBBB patients. Notably, among LBBB patients, PRp is a more important predictor than QRSd in assessing long-term outcomes. Copyright © 2017. Published by Elsevier Inc.

The Hot Horizontal-Branch Stars in omega Centauri

NASA Technical Reports Server (NTRS)

Moehler, S.; Dreizler, S.; Lanz, T.; Bono, G.; Sweigart, A. V.; Calamida, A.; Nonino, M.

2010-01-01

Context. UV observations of some massive globular clusters have revealed a significant population of stars hotter and fainter than the hot end of the horizontal branch (HB), the so-called blue hook stars. This feature might be explained either by the late hot flasher scenario where stars experience the helium flash while on the white dwarf cooling curve or by the progeny of the helium-enriched sub-population recently postulated to exist in some clusters. Previous spectroscopic analyses of blue hook stars in co Cen and NGC 2808 support the late hot flasher scenario, but the stars contain much less helium than expected and the predicted C, N enrichment could not be verified. Aims. We compare observed effective temperatures, surface gravities, helium abundances, and carbon line strengths (where detectable) of our targets stars to the predictions of the two scenarios. Methods. Moderately high resolution spectra of hot HB stars in the globular cluster omega-Cen were analysed for radial velocity variations, atmospheric parameters and abundances using LTE and non-LTE model atmospheres. Results. We find no evidence for close binaries among our target stars. All stars below 30 000 K are helium-poor and very similar to HB stars observed in that temperature range in other globular clusters. In the temperature range 30000 K to 50000 K we find that 28% of our stars are helium-poor (log ((sup n)He/(sup n )H)< - 1.6), while 72% have roughly solar or super-solar helium abundance (log ((sup n)He/(sup n )H) >/= -1.5). We also find carbon enrichment strongly correlated with helium enrichment, with a maximum carbon enrichment of 3% by mass. Conclusions. The strong carbon enrichment in tandem with helium enrichment is predicted by the late hot flasher scenario, but not by the helium-enrichment scenario. We conclude that the helium-rich HB stars in omega-Cen cannot be explained solely by the helium-enrichment scenario invoked to explain the blue main sequence.

Morphology-controlled cactus-like branched anatase TiO2 arrays with high light-harvesting efficiency for dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Wu, Wu-Qiang; Rao, Hua-Shang; Feng, Hao-Lin; Guo, Xin-Dong; Su, Cheng-Yong; Kuang, Dai-Bin

2014-08-01

The present work establishes a facile process for one-step hydrothermal growth of vertically aligned anatase cactus-like branched TiO2 (CBT) arrays on a transparent conducting oxide (TCO) substrate. Various CBT morphologies are obtained by adjusting the potassium titanium oxide oxalate (PTO) reactant concentration (from 0.05 M to 0.15 M) and this yields a morphologically-controllable branched TiO2 arrays geometry. The CBT arrays consist of a vertically oriented nanowire (NW) or nanosheet (NS) stem and a host of short nanorod (NR) branches. The hierarchical CBT arrays demonstrate their excellent candidatures as photoanodes, which are capable of exhibiting high light-harvesting efficiency in dye-sensitized solar cells (DSSCs). Consequently, DSSCs based on 7 μm long optimized CBT arrays (0.05 M PTO), which are assembled with high density and high aspect-ratio NR branches, exhibit an impressive power conversion efficiency of 6.43% under AM 1.5G one sun illumination. The high performance can be attributed to the prominent light-harvesting efficiency, resulting from larger surface area and superior light-scattering capability.

Three-dimensional reconstruction of Haversian systems in human cortical bone using synchrotron radiation-based micro-CT: morphology and quantification of branching and transverse connections across age.

PubMed

Maggiano, Isabel S; Maggiano, Corey M; Clement, John G; Thomas, C David L; Carter, Yasmin; Cooper, David M L

2016-05-01

This study uses synchrotron radiation-based micro-computed tomography (CT) scans to reconstruct three-dimensional networks of Haversian systems in human cortical bone in order to observe and analyse interconnectivity of Haversian systems and the development of total Haversian networks across different ages. A better knowledge of how Haversian systems interact with each other is essential to improve understanding of remodeling mechanisms and bone maintenance; however, previous methodological approaches (e.g. serial sections) did not reveal enough detail to follow the specific morphology of Haversian branching, for example. Accordingly, the aim of the present study was to identify the morphological diversity of branching patterns and transverse connections, and to understand how they change with age. Two types of branching morphologies were identified: lateral branching, resulting in small osteon branches bifurcating off of larger Haversian canals; and dichotomous branching, the formation of two new osteonal branches from one. The reconstructions in this study also suggest that Haversian systems frequently target previously existing systems as a path for their course, resulting in a cross-sectional morphology frequently referred to as 'type II osteons'. Transverse connections were diverse in their course from linear to oblique to curvy. Quantitative assessment of age-related trends indicates that while in younger human individuals transverse connections were most common, in older individuals more evidence of connections resulting from Haversian systems growing inside previously existing systems was found. Despite these changes in morphological characteristics, a relatively constant degree of overall interconnectivity is maintained throughout life. Altogether, the present study reveals important details about Haversian systems and their relation to each other that can be used towards a better understanding of cortical bone remodeling as well as a more accurate

Tracing the Metal-poor M31 Stellar Halo with Blue Horizontal Branch Stars

NASA Astrophysics Data System (ADS)

Williams, Benjamin F.; Dalcanton, Julianne J.; Bell, Eric F.; Gilbert, Karoline M.; Guhathakurta, Puragra; Dorman, Claire; Lauer, Tod R.; Seth, Anil C.; Kalirai, Jason S.; Rosenfield, Philip; Girardi, Leo

2015-03-01

We have analyzed new Hubble Space Telescope (HST)/Advanced Camera for Surveys and HST/WFC3 imaging in F475W and F814W of two previously unobserved fields along the M31 minor axis to confirm our previous constraints on the shape of M31's inner stellar halo. Both of these new data sets reach a depth of at least F814W <27 and clearly detect the blue horizontal branch (BHB) of the field as a distinct feature of the color-magnitude diagram. We measure the density of BHB stars and the ratio of BHB to red giant branch (RGB) stars in each field using techniques identical to our previous work. We find excellent agreement with our previous measurement of a power law for the 2D projected surface density with an index of 2.6-0.2+0.3 outside of 3 kpc, which flattens to α < 1.2 inside of 3 kpc. Our findings confirm our previous suggestion that the field BHB stars in M31 are part of the halo population. However, the total halo profile is now known to differ from this BHB profile, which suggests that we have isolated the metal-poor component. This component appears to have an unbroken power-law profile from 3-150 kpc but accounts for only about half of the total halo stellar mass. Discrepancies between the BHB density profile and other measurements of the inner halo are therefore likely due to the different profile of the metal-rich halo component, which is not only steeper than the profile of the metal-poor component, but also has a larger core radius. These profile differences also help to explain the large ratio of BHB/RGB stars in our observations.

Cux1 and Cux2 regulate dendritic branching, spine morphology and synapses of the upper layer neurons of the cortex

PubMed Central

Cubelos, Beatriz; Sebastián-Serrano, Alvaro; Beccari, Leonardo; Calcagnotto, Maria Elisa; Cisneros, Elsa; Kim, Seonhee; Dopazo, Ana; Alvarez-Dolado, Manuel; Redondo, Juan Miguel; Bovolenta, Paola; Walsh, Christopher A.; Nieto, Marta

2010-01-01

Summary Dendrite branching and spine formation determines the function of morphologically distinct and specialized neuronal subclasses. However, little is known about the programs instructing specific branching patterns in vertebrate neurons and whether such programs influence dendritic spines and synapses. Using knockout and knockdown studies combined with morphological, molecular and electrophysiological analysis we show that the homeobox Cux1 and Cux2 are intrinsic and complementary regulators of dendrite branching, spine development and synapse formation in layer II–III neurons of the cerebral cortex. Cux genes control the number and maturation of dendritic spines partly through direct regulation of the expression of Xlr3b and Xlr4b, chromatin remodeling genes previously implicated in cognitive defects. Accordingly, abnormal dendrites and synapses in Cux2−/− mice correlate with reduced synaptic function and defects in working memory. These demonstrate critical roles of Cux in dendritogenesis and highlight novel subclass-specific mechanisms of synapse regulation that contribute to the establishment of cognitive circuits. PMID:20510857

The Hot Horizontal-Branch Stars in NGC288 - Effects of Diffusion and Stratification on Their Atmospheric Parameters*

NASA Technical Reports Server (NTRS)

Moehler, S.; Dreizler, S.; LeBlanc, F.; Khalack, V.; Michaud, G.; Richer, J.; Sweigart, Allen V.; Grundahl, F.

2014-01-01

Context. NGC288 is a globular cluster with a well developed blue horizontal branch covering the so-called u-jump which indicates the onset of diffusion. It is therefore well suited to study the effects of diffusion in blue horizontal branch (HB) stars. Aims. We compare observed abundances to predictions from stellar evolution models calculated with diffusion and from stratified atmospheric models. We verify the effect of using stratified model spectra to derive atmospheric parameters. In addition we investigate the nature of the overluminous blue HB stars around the u-jump. Methods. We define a new photometric index sz from uvby measurements that is gravity sensitive between 8 000K and 12 000 K. Using medium-resolution spectra and Stroemgren photometry we determine atmospheric parameters (Teff, logg) and abundances for the blue HB stars. We use both homogeneous and stratified model spectra for our spectroscopic analyses. Results. The atmospheric parameters and masses of the hot HB stars in NGC288 show a behaviour seen also in other clusters for temperatures between 9 000K and 14 000 K. Outside this temperature range, however, they follow rather the results found for such stars in (omega)Cen. The abundances derived from our observations are for most elements (except He and P) within the abundance range expected from evolutionary models that include the effects of atomic diffusion and assume a surface mixed mass of 10(exp -7) M. The abundances predicted by stratified model atmospheres are generally significantly more extreme than observed, except for Mg. The use of stratified model spectra to determine effective temperatures, surface gravities and masses moves the hotter stars to a closer agreement with canonical evolutionary predictions. Conclusions. Our results show definite promise towards solving the long-standing issue of surface gravity and mass discrepancies for hot HB stars, but there is still much work needed to arrive at a self-consistent solution.

THE HUBBLE SPACE TELESCOPE UV LEGACY SURVEY OF GALACTIC GLOBULAR CLUSTERS. VII. IMPLICATIONS FROM THE NEARLY UNIVERSAL NATURE OF HORIZONTAL BRANCH DISCONTINUITIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, T. M.; Bellini, A.; Anderson, J.

2016-05-01

The UV-initiative Hubble Space Telescope Treasury survey of Galactic globular clusters provides a new window into the phenomena that shape the morphological features of the horizontal branch (HB). Using this large and homogeneous catalog of UV and blue photometry, we demonstrate that the HB exhibits discontinuities that are remarkably consistent in color (effective temperature). This consistency is apparent even among some of the most massive clusters hosting multiple distinct sub-populations (such as NGC 2808, ω Cen, and NGC 6715), demonstrating that these phenomena are primarily driven by atmospheric physics that is independent of the underlying population properties. However, inconsistencies arisemore » in the metal-rich clusters NGC 6388 and NGC 6441, where the discontinuity within the blue HB (BHB) distribution shifts ∼1000–2000 K hotter. We demonstrate that this shift is likely due to a large helium enhancement in the BHB stars of these clusters, which in turn affects the surface convection and evolution of such stars. Our survey also increases the number of Galactic globular clusters known to host blue-hook stars (also known as late hot flashers) from 6 to 23 clusters. These clusters are biased toward the bright end of the globular cluster luminosity function, confirming that blue-hook stars tend to form in the most massive clusters with significant self-enrichment.« less

Pd@Pt Core–Shell Nanoparticles with Branched Dandelion-like Morphology as Highly Efficient Catalysts for Olefin Reduction

EPA Science Inventory

A facile synthesis based on the addition of ascorbic acid to a mixture of Na2PdCl4, K2PtCl6, and Pluronic P123 results in highly branched core–shell nanoparticles (NPs) with a micro–mesoporous dandelion-like morphology comprising Pd core and Pt shell. The slow reduction kinetics ...

Exploring the Chemical Composition and Double Horizontal Branch of the Bulge Globular Cluster NGC 6569

NASA Astrophysics Data System (ADS)

Johnson, Christian I.; Rich, R. Michael; Caldwell, Nelson; Mateo, Mario; Bailey, John I., III; Olszewski, Edward W.; Walker, Matthew G.

2018-02-01

Photometric and spectroscopic analyses have shown that the Galactic bulge cluster Terzan 5 hosts several populations with different metallicities and ages that manifest as a double red horizontal branch (HB). A recent investigation of the massive bulge cluster NGC 6569 revealed a similar, though less extended, HB luminosity split, but little is known about the cluster’s detailed chemical composition. Therefore, we have used high-resolution spectra from the Magellan–M2FS and VLT–FLAMES spectrographs to investigate the chemical compositions and radial velocity distributions of red giant branch and HB stars in NGC 6569. We found the cluster to have a mean heliocentric radial velocity of ‑48.8 km s‑1 (σ = 5.3 km s‑1 148 stars) and < [{Fe}/{{H}}]> =-0.87 dex (19 stars), but the cluster’s 0.05 dex [Fe/H] dispersion precludes a significant metallicity spread. NGC 6569 exhibits light- and heavy-element distributions that are common among old bulge/inner Galaxy globular clusters, including clear (anti)correlations between [O/Fe], [Na/Fe], and [Al/Fe]. The light-element data suggest that NGC 6569 may be composed of at least two distinct populations, and the cluster’s low < [{La}/{Eu}]> =-0.11 dex indicates significant pollution with r-process material. We confirm that both HBs contain cluster members, but metallicity and light-element variations are largely ruled out as sources for the luminosity difference. However, He mass fraction differences as small as ΔY ∼ 0.02 cannot be ruled out and may be sufficient to reproduce the double HB.

Chemical and Kinematical Properties of Blue Straggler Stars and Horizontal Branch Stars in NGC 6397

NASA Astrophysics Data System (ADS)

Lovisi, L.; Mucciarelli, A.; Lanzoni, B.; Ferraro, F. R.; Gratton, R.; Dalessandro, E.; Contreras Ramos, R.

2012-08-01

We used three sets of high-resolution spectra acquired with the multifiber facility FLAMES at the Very Large Telescope of the European Southern Observatory to investigate the chemical and kinematical properties of a sample of 42 horizontal branch (HB) stars, 18 blue straggler stars (BSSs), and 86 main-sequence (MS) turnoff (TO) and sub-giant branch stars in the nearby globular cluster NGC 6397. We measured rotational velocities and Fe, O, and Mg abundances. All of the unevolved stars in our sample have low rotational velocites (vsin i < 10 km s-1), while the HB stars and BSSs show a broad distribution, with values ranging from 0 to ~70 km s-1. For HB stars with T < 10,500 K there is a clear temperature-oxygen anticorrelation that can be understood if the star position along the HB is mainly determined by the He content. The hottest BSSs and HB stars (with temperatures T > 8200 K and T > 10,500 K, respectively) also show significant deviations in their iron abundance with respect to the cluster metallicity (as traced by the unevolved stars, [Fe/H] = -2.12). While similar chemical patterns have already been observed in other hot HB stars, this is the first evidence ever collected for BSSs. We interpret these abundance anomalies as due to the metal radiative levitation, occurring in stars with shallow or no convective envelopes. Based on FLAMES observations collected at the European Southern Observatory, proposal numbers 073.D-0058, 075.D-0125, and 081.D-0356.

Mapping Milky Way Halo Structure with Blue Horizontal Branch Stars

NASA Astrophysics Data System (ADS)

Martin, Charles; Newberg, Heidi Jo; Carlin, Jeffrey L.

2017-01-01

The use of blue horizontal brach (BHB) and red giant branch stars as tracers of stellar debris streams is a common practice and has been useful in the confirmation of kinematic properties of previously identified streams. This work explores less common ways of untangling the velocity signatures of streams traveling radially to our line of sight, and to peer toward the higher density region of the Galactic Center using data from the Sloan Digital Sky Survey (SDSS). Using spectra of BHB stars, we are able to kinematically distinguish moving groups in the Milky Way halo. The results of this thesis advance our knowledge of the following stellar halo substructures: the Pisces Stellar Stream, the Hercules-Aquila Cloud, the Hercules Halo Stream, and the Hermus Stream. A study of red giant stars led to the kinematic discovery of the Pisces Stellar Stream. Red giant stars were also examined to determine that the previously identified velocity signature that was suggested for the Hercules-Aquila Cloud was due to disk star contamination and errors in preliminary SDSS velocities. The Hercules Halo Stream is a previously unidentified structure that could be related to the Hercules-Aquila Cloud, and was discovered as a velocity excess of SDSS BHB stars. We identify a group of 10 stars with similar velocities that are spatially coincident with the Hermus Stream. An orbit is fit to the Hermus Stream that rules out a connection with the Phoenix Stream.This work was supported by NSF grants AST 09-37523, 14-09421, 16-15688, the NASA/NY Space Grant fellowship, and contributions made by The Marvin Clan, Babette Josephs, Manit Limlamai, and the 2015 Crowd Funding Campaign to Support Milky Way Research.

Rotational broadening and conservation of angular momentum in post-extreme horizontal branch stars

NASA Astrophysics Data System (ADS)

Fontaine, G.; Latour, M.

2018-06-01

We show that the recent realization that isolated post-extreme horizontal branch (post-EHB) stars are generally characterized by rotational broadening with values of V rot sini between 25 and 30 km s-1 can be explained as a natural consequence of the conservation of angular momentum from the previous He-core burning phase on the EHB. The progenitors of these evolved objects, the EHB stars, are known to be slow rotators with an average value of V rot sini of 7.7 km s-1. This implies significant spin-up between the EHB and post-EHB phases. Using representative evolutionary models of hot subdwarf stars, we demonstrate that angular momentum conservation in uniformly rotating structures (rigid-body rotation) boosts that value of the projected equatorial rotation speed by a factor 3.6 by the time the model has reached the region of the surface gravity-effective temperature plane where the newly-studied post-EHB objects are found. This is exactly what is needed to account for their observed atmospheric broadening. We note that the decrease of the moment of inertia causing the spin-up is mostly due to the redistribution of matter that produces more centrally-condensed structures in the post-EHB phase of evolution, not to the decrease of the radius per se.

Arrhythmogenic Right Ventricular Cardiomyopathy with Multiple Thrombi and Ventricular Tachycardia of Atypical Left Branch Bundle Block Morphology.

PubMed

Gong, Shenzhen; Wei, Xin; Liu, Guyue; Wu, Feng; Chen, Xiaoping

2018-04-06

A 61-year-old male patient was admitted to our hospital with recurrent palpitations and syncope. Electrocardiography, echocardiography, and contrast-enhanced computed tomography were performed. The patient was diagnosed with arrhythmogenic right ventricular cardiomyopathy (ARVC) complicated by multiple thrombi, and ventricular tachycardia (VT) without typical left bundle branch block (LBBB) morphology. This case suggests that VT is not always the sole contributor to syncope and death in patients with ARVC, and pulmonary embolism should be considered. Furthermore, VT with typical LBBB morphology is not an absolute necessity as a major criterion for the diagnosis of ARVC when the right heart is extremely enlarged.

Shear-induced enhancements of crystallization kinetics and morphological transformation for long chain branched polylactides with different branching degrees

PubMed Central

Wang, Junyang; Bai, Jing; Zhang, Yaqiong; Fang, Huagao; Wang, Zhigang

2016-01-01

The effects of long chain branching (LCB) degree on the shear-induced isothermal crystallization kinetics of a series of LCB polylactides (LCB PLAs) have been investigated by using rotational rheometer, polarized optical microscopy (POM) and scanning electron microscopy (SEM). Dynamic viscoelastic properties obtained by small-amplitude oscillatory shear (SAOS) tests indicate that LCB PLAs show more broadened relaxation time spectra with increasing LCB degree. Upon a pre-shear at the shear rate of 1 s−1 LCB PLAs show much faster crystallization kinetics than linear PLA and the crystallization kinetics is enhanced with increasing LCB degree. By modeling the system as a suspension the quantitative evaluation of nucleation density can be derived from rheological experiments. The nucleation density is greatly enhanced with increasing LCB degree and a saturation in shear time is observed. Crystalline morphologies for LCB PLAs observed by POM and SEM demonstrate the enhancement of nucleation density with increasing LCB degree and a transformation from spherulitic to orientated crystalline morphologies. The observation can be ascribed to longer relaxation time of the longest macromolecular chains and broadened, complex relaxation behaviors due to the introduction of LCB into PLA, which is essential in stabilizing the orientated crystal nuclei after pre-shear. PMID:27246803

Revisiting the variable star population in NGC 6229 and the structure of the horizontal branch

NASA Astrophysics Data System (ADS)

Arellano Ferro, A.; Mancera Piña, P. E.; Bramich, D. M.; Giridhar, Sunetra; Ahumada, J. A.; Kains, N.; Kuppuswamy, K.

2015-09-01

We report an analysis of new V and I CCD time series photometry of the distant globular cluster NGC 6229. The principal aims were to explore the field of the cluster in search of new variables, and to Fourier decompose the RR Lyrae light curves in pursuit of physical parameters. We found 25 new variables: 10 RRab, 5 RRc, 6 SR, 1 CW, 1 SX Phe, and 2 that we were unable to classify. Secular period changes were detected and measured in some favourable cases. The classifications of some of the known variables were rectified. The Fourier decomposition of RRab and RRc light curves was used to independently estimate the mean cluster value of [Fe/H] and distance. From the RRab stars we found [Fe/H]UVES = -1.31 ± 0.01(statistical) ± 0.12(systematic) ([Fe/H]ZW = -1.42) and a distance of 30.0 ± 1.5 kpc, and from the RRc stars we found [Fe/H]UVES = -1.29 ± 0.12 and a distance of 30.7 ± 1.1 kpc, respectively. Absolute magnitudes, radii and masses are also reported for individual RR Lyrae stars. Also discussed are the independent estimates of the cluster distance from the tip of the red giant branch, 34.9 ± 2.4 kpc and from the period-luminosity relation of SX Phe stars, 28.9 ± 2.2 kpc. The distribution of RR Lyrae stars in the horizontal branch shows a clear empirical border between stable fundamental and first overtone pulsators which has been noted in several other clusters; we interpret it as the red edge of the first overtone instability strip.

The evolution of high-metallicity horizontal-branch stars and the origin of the ultraviolet light in elliptical galaxies

NASA Technical Reports Server (NTRS)

Horch, E.; Demarque, P.; Pinsonneault, M.

1992-01-01

Evolutionary calculations of high-metallicity horizontal-branch stars show that for the relevant masses and helium abundances, post-HB evolution in the HR diagram does not proceed toward and along the AGB, but rather toward a 'slow blue phase' in the vicinity of the helium-burning main sequence, following the extinction of the hydrogen shell energy source. For solar and twice solar metallicity, the blue phase begins during the helium shell-burning phase (in agreement with the work of Brocato and Castellani and Tornambe); for 3 times solar metallicity, it begins earlier, during the helium core-burning phase. This behavior differs from what takes place at lower metallicities. The implications for high-metallicity old stellar populations in the Galactic bulge and for the integrated colors of elliptical galaxies are discussed.

The morphology of blends of linear and branched polyethylenes in solid state by small-angle scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wignall, G.D.; Londono, J.D.; Alamo, R.G.

1995-12-01

We have used small-angle neutron and x-ray scattering (SANS And SAXS) to investigate the solid state morphology of blends of high-density and low-density polyethylenes (HDPE and LDPE). The blends are homogenous in the melt as demonstrated by SANS using the contrast obtained by deuterating the linear polymer, though they phase segregate on slow cooling (0.75{degree}C/min). For high concentrations ({theta} {ge} 0.5) of linear polymer, there are separate stacks of HDPE and LDPE lamellae, as indicated by 2-peak SAXS curves. For predominantly branched blends, the phase separation is less complete, and the components are separated within the same lamellar stack, withmore » alternating HDPE and LDPE lamellae. Moreover, the phases no longer consist of the pure components and the HDPE lamellae contain up to 15% LDPE. Rapid quenching into dry-ice/acetone (-78{degree}C) produces only one lamellar stack over the whole concentration range. The blends show extensive cocrystallization with a tendency for the branched material to be preferentially located in the amorphous regions. For high concentrations ({theta} {ge} 0.5) of HDPE-D the overall scattering length density is high and the excess concentration of LDPE between the lamellae enhances the contrast between the crystalline and amorphous phases. Thus, the interlamellar spacing (long period) is clearly visible in the SANS pattern. The blend morphology is a strong function of the quench rate and samples quenched less rapidly (e.g., into water at 23{degree}C) show a similar morphology to slowly cooled samples.« less

Observations of the Hot Horizontal Branch Stars in the Metal-Rich Bulge Globular Cluster NGC 6388

NASA Technical Reports Server (NTRS)

Moehler, S.; Sweigart, A. V.

2006-01-01

The metal-rich bulge globular cluster NGC 6388 shows a distinct blue horizontal-branch tail in its colour-magnitude diagram (Rich et al. 1997) and is thus a strong case of the well-known 2nd Parameter Problem. In addition, its horizontal branch (HB) shows an upward tilt toward bluer colours, which cannot be explained by canonical evolutionary models. Several non-canonical scenarios have been proposed to explain these puzzling observations. In order to test the predictions of these scenarios, we have obtained medium resolution spectra to determine the atmospheric parameters of a sample of the blue HB stars in NGC 6388.Using the medium resolution spectra, we determine effective temperatures, surface gravities and helium abundances by fitting the observed Balmer and helium lines with appropriate theoretical stellar spectra. As we know the distance to the cluster, we can verify our results by determining masses for the stars. During the data reduction we took special care to correctly subtract the background, which is dominated by the overlapping spectra of cool stars. The cool blue tail stars in our sample with T(sub eff) approximately 10000 K have lower than canonical surface gravities, suggesting that these stars are, on average, approximately equal to 0.4 mag brighter than canonical HB stars in agreement with the observed upward slope of the HB in NGC 6388. Moreover, the mean mass of these stars agrees well with theoretical predictions. In contrast, the hot blue tail stars in our sample with T(sub eff) greater than or equal to 12000 K show significantly lower surface gravities than predicted by any scenario, which can reproduce the photometric observations. Their masses are also too low by about a factor of 2 compared to theoretical predictions. The physical parameters of the blue HB stars at about 10,000 K support the helium pollution scenario. The low gravities and masses of the hot blue tail stars, however, are probably caused by problems with the data reduction

Rotations and Abundances of Blue Horizontal-Branch Stars in Globular Cluster M15.

PubMed

Behr; Cohen; McCarthy

2000-03-01

High-resolution optical spectra of 18 blue horizontal-branch stars in the globular cluster M15 indicate that their stellar rotation rates and photospheric compositions vary strongly as a function of effective temperature. Among the cooler stars in the sample, at Teff approximately 8500 K, metal abundances are in rough agreement with the canonical cluster metallicity, and the vsini rotations appear to have a bimodal distribution, with eight stars at vsini<15 km s-1 and two stars at vsini approximately 35 km s-1. Most of the stars at Teff>/=10,000 K, however, are slowly rotating, vsini<7 km s-1, and their iron and titanium are enhanced by a factor of 300 to solar abundance levels. Magnesium maintains a nearly constant abundance over the entire range of Teff, and helium is depleted by factors of 10-30 in three of the hotter stars. Diffusion effects in the stellar atmospheres are the most likely explanation for these large differences in composition. Our results are qualitatively very similar to those previously reported for M13 and NGC 6752, but with even larger enhancement amplitudes, presumably due to the increased efficiency of radiative levitation at lower intrinsic [Fe/H]. We also see evidence for faster stellar rotation explicitly preventing the onset of the diffusion mechanisms among a subset of the hotter stars.

Just how hot are the ω Centauri extreme horizontal branch pulsators?

NASA Astrophysics Data System (ADS)

Latour, M.; Randall, S. K.; Chayer, P.; Fontaine, G.; Calamida, A.; Ely, J.; Brown, T. M.; Landsman, W.

2017-04-01

Context. Past studies based on optical spectroscopy suggest that the five ω Cen pulsators form a rather homogeneous group of hydrogen-rich subdwarf O stars with effective temperatures of around 50 000 K. This places the stars below the red edge of the theoretical instability strip in the log g-Teff diagram, where no pulsation modes are predicted to be excited. Aims: Our goal is to determine whether this temperature discrepancy is real, or whether the stars' effective temperatures were simply underestimated. Methods: We present a spectral analysis of two rapidly pulsating extreme horizontal branch (EHB) stars found in ω Cen. We obtained Hubble Space Telescope/COS UV spectra of two ω Cen pulsators, V1 and V5, and used the ionisation equilibrium of UV metallic lines to better constrain their effective temperatures. As a by-product we also obtained FUV lightcurves of the two pulsators. Results: Using the relative strength of the N iv and N v lines as a temperature indicator yields Teff values close to 60 000 K, significantly hotter than the temperatures previously derived. From the FUV light curves we were able to confirm the main pulsation periods known from optical data. Conclusions: With the UV spectra indicating higher effective temperatures than previously assumed, the sdO stars would now be found within the predicted instability strip. Such higher temperatures also provide consistent spectroscopic masses for both the cool and hot EHB stars of our previously studied sample. Based on observations (proposal GO-13707) with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26666.

The Transcriptomes of Xiphinema index and Longidorus elongatus Suggest Independent Acquisition of Some Plant Parasitism Genes by Horizontal Gene Transfer in Early-Branching Nematodes

PubMed Central

Danchin, Etienne G.J.; Perfus-Barbeoch, Laetitia; Rancurel, Corinne; Thorpe, Peter; Da Rocha, Martine; Bajew, Simon; Neilson, Roy; Sokolova (Guzeeva), Elena; Da Silva, Corinne; Guy, Julie; Labadie, Karine; Esmenjaud, Daniel; Helder, Johannes; Jones, John T.

2017-01-01

Nematodes have evolved the ability to parasitize plants on at least four independent occasions, with plant parasites present in Clades 1, 2, 10 and 12 of the phylum. In the case of Clades 10 and 12, horizontal gene transfer of plant cell wall degrading enzymes from bacteria and fungi has been implicated in the evolution of plant parasitism. We have used ribonucleic acid sequencing (RNAseq) to generate reference transcriptomes for two economically important nematode species, Xiphinema index and Longidorus elongatus, representative of two genera within the early-branching Clade 2 of the phylum Nematoda. We used a transcriptome-wide analysis to identify putative horizontal gene transfer events. This represents the first in-depth transcriptome analysis from any plant-parasitic nematode of this clade. For each species, we assembled ~30 million Illumina reads into a reference transcriptome. We identified 62 and 104 transcripts, from X. index and L. elongatus, respectively, that were putatively acquired via horizontal gene transfer. By cross-referencing horizontal gene transfer prediction with a phylum-wide analysis of Pfam domains, we identified Clade 2-specific events. Of these, a GH12 cellulase from X. index was analysed phylogenetically and biochemically, revealing a likely bacterial origin and canonical enzymatic function. Horizontal gene transfer was previously shown to be a phenomenon that has contributed to the evolution of plant parasitism among nematodes. Our findings underline the importance and the extensiveness of this phenomenon in the evolution of plant-parasitic life styles in this speciose and widespread animal phylum. PMID:29065523

The Transcriptomes of Xiphinema index and Longidorus elongatus Suggest Independent Acquisition of Some Plant Parasitism Genes by Horizontal Gene Transfer in Early-Branching Nematodes.

PubMed

Danchin, Etienne G J; Perfus-Barbeoch, Laetitia; Rancurel, Corinne; Thorpe, Peter; Da Rocha, Martine; Bajew, Simon; Neilson, Roy; Guzeeva, Elena Sokolova; Da Silva, Corinne; Guy, Julie; Labadie, Karine; Esmenjaud, Daniel; Helder, Johannes; Jones, John T; den Akker, Sebastian Eves-van

2017-10-23

Nematodes have evolved the ability to parasitize plants on at least four independent occasions, with plant parasites present in Clades 1, 2, 10 and 12 of the phylum. In the case of Clades 10 and 12, horizontal gene transfer of plant cell wall degrading enzymes from bacteria and fungi has been implicated in the evolution of plant parasitism. We have used ribonucleic acid sequencing (RNAseq) to generate reference transcriptomes for two economically important nematode species, Xiphinema index and Longidorus elongatus , representative of two genera within the early-branching Clade 2 of the phylum Nematoda. We used a transcriptome-wide analysis to identify putative horizontal gene transfer events. This represents the first in-depth transcriptome analysis from any plant-parasitic nematode of this clade. For each species, we assembled ~30 million Illumina reads into a reference transcriptome. We identified 62 and 104 transcripts, from X. index and L. elongatus , respectively, that were putatively acquired via horizontal gene transfer. By cross-referencing horizontal gene transfer prediction with a phylum-wide analysis of Pfam domains, we identified Clade 2-specific events. Of these, a GH12 cellulase from X. index was analysed phylogenetically and biochemically, revealing a likely bacterial origin and canonical enzymatic function. Horizontal gene transfer was previously shown to be a phenomenon that has contributed to the evolution of plant parasitism among nematodes. Our findings underline the importance and the extensiveness of this phenomenon in the evolution of plant-parasitic life styles in this speciose and widespread animal phylum.

Developmental Programming of Branching Morphogenesis in the Kidney

PubMed Central

Schneider, Laura; Al-Awqati, Qais

2015-01-01

The kidney developmental program encodes the intricate branching and organization of approximately 1 million functional units (nephrons). Branching regulation is poorly understood, as is the source of a 10-fold variation in nephron number. Notably, low nephron count increases the risk for developing hypertension and renal failure. To better understand the source of this variation, we analyzed the complete gestational trajectory of mouse kidney development. We constructed a computerized architectural map of the branching process throughout fetal life and found that organogenesis is composed of two distinct developmental phases, each with stage-specific rate and morphologic parameters. The early phase is characterized by a rapid acceleration in branching rate and by branching divisions that repeat with relatively reproducible morphology. The latter phase, however, is notable for a significantly decreased yet constant branching rate and the presence of nonstereotyped branching events that generate progressive variability in tree morphology until birth. Our map identifies and quantitates the contribution of four developmental mechanisms that guide organogenesis: growth, patterning, branching rate, and nephron induction. When applied to organs that developed under conditions of malnutrition or in the setting of growth factor mutation, our normative map provided an essential link between kidney architecture and the fundamental morphogenetic mechanisms that guide development. This morphogenetic map is expected to find widespread applications and help identify modifiable targets to prevent developmental programming of common diseases. PMID:25644110

Developmental Programming of Branching Morphogenesis in the Kidney.

PubMed

Sampogna, Rosemary V; Schneider, Laura; Al-Awqati, Qais

2015-10-01

The kidney developmental program encodes the intricate branching and organization of approximately 1 million functional units (nephrons). Branching regulation is poorly understood, as is the source of a 10-fold variation in nephron number. Notably, low nephron count increases the risk for developing hypertension and renal failure. To better understand the source of this variation, we analyzed the complete gestational trajectory of mouse kidney development. We constructed a computerized architectural map of the branching process throughout fetal life and found that organogenesis is composed of two distinct developmental phases, each with stage-specific rate and morphologic parameters. The early phase is characterized by a rapid acceleration in branching rate and by branching divisions that repeat with relatively reproducible morphology. The latter phase, however, is notable for a significantly decreased yet constant branching rate and the presence of nonstereotyped branching events that generate progressive variability in tree morphology until birth. Our map identifies and quantitates the contribution of four developmental mechanisms that guide organogenesis: growth, patterning, branching rate, and nephron induction. When applied to organs that developed under conditions of malnutrition or in the setting of growth factor mutation, our normative map provided an essential link between kidney architecture and the fundamental morphogenetic mechanisms that guide development. This morphogenetic map is expected to find widespread applications and help identify modifiable targets to prevent developmental programming of common diseases. Copyright © 2015 by the American Society of Nephrology.

Different Characteristics of the Bright Branches of the Globular Clusters M15 and M92

NASA Astrophysics Data System (ADS)

Cho, Dong-Hwan; Lee, Sang-Gak

2007-05-01

We carried out relatively wide-field BVI CCD photometric observations of the globular clusters M15 (NGC 7078) and M92 (NGC 6341) using the 1.8 m telescope of the Bohyun Optical Astronomy Observatory. We present color-magnitude diagrams (V vs. B-V, V vs. V-I, and V vs. B-I) of M15 and M92. We found asymptotic giant branch (AGB) bumps at VbumpAGB=15.20+/-0.05 mag and VbumpAGB=14.50+/-0.05 mag for M15 and M92, respectively. We identified the red giant branch (RGB) bumps of the two clusters. We have estimated the population ratios R and R2 for M15 and M92 in two cases: when only normal horizontal-branch (HB) stars are used and when all the HB stars are used. We have compared the observed RGB luminosity functions of M15 and M92 with the theoretical RGB luminosity functions of Bergbusch & VandenBerg and found no significant ``extra stars'' in the comparisons. This implies that the HB morphology difference between M15 and M92 is not certain due to the results of deep mixing in the RGB sequence.

Field Red Horizontal Branch Star Chemical Compositions from High Resolution Infrared Spectra

NASA Astrophysics Data System (ADS)

Sneden, Chris; Afsar, Melike; Bozkurt, Zeynep; Bocek-Topcu, Gamze; Mace, Gregory N.; Kim, Hwihyun; Kaplan, Kyle; Kidder, Benjamin; McLane, Jacob

2017-06-01

We have observed three field red horizontal branch stars with the Immersion Grating Infrared Spectrograph (IGRINS). The high resolution (R~45000) high signal-to-noise (S/N > 200) spectra obtained with IGRINS cover the complete H-band (1.50-1.80 micron) and K-band (1.90-2.45 micron). We analyzed hundreds of lines of the ubiquitous OH, CN, and CO molecular bands, and found more than 80 lines of atomic species that were useful for abundance work. A combination of good laboratory transition probabilities (when available) and ones derived from reverse solar analyses were employed. Our transition data were checked through studies of the Arcturus Atlas spectrum. We derived abundances from synthetic spectra instead of from equivalent widths. With IGRINS data we were able to extract metallicities and abundance ratios for more than 20 elements, including several not detectable or poorly represented in optical wavelength regions. Our abundances from IGRINS spectra are in excellent accord with those derived from optical spectrum studies. These results are directly applicable to calibrations of results from lower-resolution and/or S/N infrared spectral surveys. IGRINS observations will give high reolution spectroscopic access to heavily obscured normal red giants and other cool stars with unusual element mixes.This work used the Immersion Grating Infrared Spectrograph (IGRINS) that was developed under a collaboration between the University of Texas at Austin and the Korea Astronomy and Space Science Institute (KASI) with the financial support of the US National Science Foundation (NSF; grant AST-1229522), of the University of Texas at Austin, and of the Korean GMT Project of KASI. Our project also has been supported by NSF grants AST~1211585 and AST~1616040, by the University of Texas Rex G. Baker, Jr. Centennial Research Endowment, and by The Scientific and Technological Research Council of Turkey (TUBITAK, project No. 112T929).

What Happens in the Atmospheres of Hot Horizontal Branch Stars Near 20, 000K?

NASA Astrophysics Data System (ADS)

Brown, Thomas

2016-10-01

In the color-magnitude diagrams (CMDs) of many globular clusters, the horizontal branch (HB) exhibits a long blue tail extending to high effective temperatures. In such clusters, two discontinuities appear within the HB locus. The first discontinuity occurs at 12,000K, and was discovered by Grundahl et al. (1998). It is associated with the radiative levitation of metals and the gravitational settling of helium in the atmospheres of HB stars hotter than 12,000K. The hot subdwarf stars of the Galactic field population exhibit the same phenomenon. The second discontinuity occurs at 20,000K, and was discovered by Momany et al. (2002). Its origin is unknown, but it appears at the same effective temperature in all globular clusters hosting HB stars near 20,000K, regardless of cluster properties (age, chemical composition, mass, etc.). We propose STIS long-slit spectroscopy of 6 HB stars that straddle this feature in the HB distribution of omega Cen, the nearest globular cluster where the feature is well populated. With this approach, we can efficiently obtain high-quality UV and blue spectra that span the full wavelength range of the photometric bands where this CMD feature is most prominent - a range this is only accessible by HST. The resulting spectra will unambiguously reveal the nature of this phenomenon - one that is universal in the atmospheres of hot evolved stars - and will yield new insight into the role of diffusion and radiative levitation in these stars.

THE PANCHROMATIC HUBBLE ANDROMEDA TREASURY. II. TRACING THE INNER M31 HALO WITH BLUE HORIZONTAL BRANCH STARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Benjamin F.; Dalcanton, Julianne J.; Gilbert, Karoline M.

We attempt to constrain the shape of M31's inner stellar halo by tracing the surface density of blue horizontal branch (BHB) stars at galactocentric distances ranging from 2 kpc to 35 kpc. Our measurements make use of resolved stellar photometry from a section of the Panchromatic Hubble Andromeda Treasury survey, supplemented by several archival Hubble Space Telescope observations. We find that the ratio of BHB to red giant stars is relatively constant outside of 10 kpc, suggesting that the BHB is as reliable a tracer of the halo population as the red giant branch. In the inner halo, we domore » not expect BHB stars to be produced by the high-metallicity bulge and disk, making BHB stars a good candidate to be a reliable tracer of the stellar halo to much smaller galactocentric distances. If we assume a power-law profile r {sup -{alpha}} for the two-dimensional (2D) projected surface density BHB distribution, we obtain a high-quality fit with a 2D power-law index of {alpha} = 2.6{sup +0.3} {sub -0.2} outside of 3 kpc, which flattens to {alpha} < 1.2 inside of 3 kpc. This slope is consistent with previous measurements but is anchored to a radial baseline that extends much farther inward. Finally, assuming azimuthal symmetry and a constant mass-to-light ratio, the best-fitting profile yields a total halo stellar mass of 2.1{sup +1.7} {sub -0.4} Multiplication-Sign 10{sup 9} M {sub Sun }. These properties are comparable with both simulations of stellar halo formation by satellite disruption alone and simulations that include some in situ formation of halo stars.« less

PpeTAC1 promotes the horizontal growth of branches in peach trees and is a member of a functionally conserved gene family found in diverse plants species.

PubMed

Dardick, Chris; Callahan, Ann; Horn, Renate; Ruiz, Karina B; Zhebentyayeva, Tetyana; Hollender, Courtney; Whitaker, Michael; Abbott, Albert; Scorza, Ralph

2013-08-01

Trees are capable of tremendous architectural plasticity, allowing them to maximize their light exposure under highly competitive environments. One key component of tree architecture is the branch angle, yet little is known about the molecular basis for the spatial patterning of branches in trees. Here, we report the identification of a candidate gene for the br mutation in Prunus persica (peach) associated with vertically oriented growth of branches, referred to as 'pillar' or 'broomy'. Ppa010082, annotated as hypothetical protein in the peach genome sequence, was identified as a candidate gene for br using a next generation sequence-based mapping approach. Sequence similarity searches identified rice TAC1 (tiller angle control 1) as a putative ortholog, and we thus named it PpeTAC1. In monocots, TAC1 is known to lead to less compact growth by increasing the tiller angle. In Arabidopsis, an attac1 mutant showed more vertical branch growth angles, suggesting that the gene functions universally to promote the horizontal growth of branches. TAC1 genes belong to a gene family (here named IGT for a shared conserved motif) found in all plant genomes, consisting of two clades: one containing TAC1-like genes; the other containing LAZY1, which contains an EAR motif, and promotes vertical shoot growth in Oryza sativa (rice) and Arabidopsis through influencing polar auxin transport. The data suggest that IGT genes are ancient, and play conserved roles in determining shoot growth angles in plants. Understanding how IGT genes modulate branch angles will provide insights into how different architectural growth habits evolved in terrestrial plants. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

["Habitual" left branch block alternating with 2 "disguised" bracnch block].

PubMed

Lévy, S; Jullien, G; Mathieu, P; Mostefa, S; Gérard, R

1976-10-01

Two cases of alternating left bundle branch block and "masquerading block" (with left bundle branch morphology in the stnadard leads and right bundle branch block morphology in the precordial leads) were studied by serial tracings and his bundle electrocardiography. In case 1 "the masquerading" block was associated with a first degree AV block related to a prolongation of HV interval. This case is to our knowledge the first cas of alternating bundle branch block in which his bundle activity was recorded in man. In case 2, the patient had atrial fibrilation and His bundle recordings were performed while differents degrees of left bundle branch block were present: The mechanism of the alternation and the concept of "masquerading" block are discussed. It is suggested that this type of block represents a right bundle branch block associated with severe lesions of the "left system".

Universal features of dendrites through centripetal branch ordering

PubMed Central

Effenberger, Felix; Muellerleile, Julia

2017-01-01

Dendrites form predominantly binary trees that are exquisitely embedded in the networks of the brain. While neuronal computation is known to depend on the morphology of dendrites, their underlying topological blueprint remains unknown. Here, we used a centripetal branch ordering scheme originally developed to describe river networks—the Horton-Strahler order (SO)–to examine hierarchical relationships of branching statistics in reconstructed and model dendritic trees. We report on a number of universal topological relationships with SO that are true for all binary trees and distinguish those from SO-sorted metric measures that appear to be cell type-specific. The latter are therefore potential new candidates for categorising dendritic tree structures. Interestingly, we find a faithful correlation of branch diameters with centripetal branch orders, indicating a possible functional importance of SO for dendritic morphology and growth. Also, simulated local voltage responses to synaptic inputs are strongly correlated with SO. In summary, our study identifies important SO-dependent measures in dendritic morphology that are relevant for neural function while at the same time it describes other relationships that are universal for all dendrites. PMID:28671947

A Search for Extreme Horizontal Branch Stars in the General Field Population (Abstract)

NASA Astrophysics Data System (ADS)

Walker, D.; Albrow, M.

2014-12-01

(Abstract only) The study of pulsating Extreme Horizontal Branch (EHB) stars in globular clusters is a new field of stellar research. The initial discovery of three rapidly pulsating EHB stars in w Centauri was announced at the Fourth Meeting on Hot Subdwarfs and Related Objects held in Shanghai in July 2009. A fourth sdB pulsator was discovered in the remaining photometry data soon afterwards; all were discovered in data obtained by the New Techology Telescope. In March 2013, the Space Telescope Imaging Spectrograph (STIS) was utilized on five consecutive orbits to obtain far-UV imagery of NGC 2808’s core, revealing six sdB pulsators with periods 85 to 149 seconds and UV amplitudes from 2.0 to 6.8%. To date (April 2014), these ten EHB pulsators in w Centauri and NGC 2808 form a unique class of EHB variable closely clustered around Teff ~ 50,000 K. This talk describes an initial candidate search for EHB rapidly pulsating sdB stars in the general galactic field population. The search was conducted with the 1-m McLellan telescope at the Mt. John University Observatory (MJUO) at Lake Tekapo, New Zealand. Observations were conducted utilizing a special high speed f/8 frame-transfer camera called the Puoko-nui. The candidate set of stars was taken from the Edinburgh-Cape Blue Object Survey based on the selection criteria of a (B-V) value of -0.32 to -0.36, corresponding to the desired temperature range Teff ranging from 40,000 to 64,000 K. The objective of this search was to determine whether smaller size telescopes could identify promising sets of candidate sdB pulsators which could be followed up with larger professional systems.

Tree Branching: Leonardo da Vinci's Rule versus Biomechanical Models

PubMed Central

Minamino, Ryoko; Tateno, Masaki

2014-01-01

This study examined Leonardo da Vinci's rule (i.e., the sum of the cross-sectional area of all tree branches above a branching point at any height is equal to the cross-sectional area of the trunk or the branch immediately below the branching point) using simulations based on two biomechanical models: the uniform stress and elastic similarity models. Model calculations of the daughter/mother ratio (i.e., the ratio of the total cross-sectional area of the daughter branches to the cross-sectional area of the mother branch at the branching point) showed that both biomechanical models agreed with da Vinci's rule when the branching angles of daughter branches and the weights of lateral daughter branches were small; however, the models deviated from da Vinci's rule as the weights and/or the branching angles of lateral daughter branches increased. The calculated values of the two models were largely similar but differed in some ways. Field measurements of Fagus crenata and Abies homolepis also fit this trend, wherein models deviated from da Vinci's rule with increasing relative weights of lateral daughter branches. However, this deviation was small for a branching pattern in nature, where empirical measurements were taken under realistic measurement conditions; thus, da Vinci's rule did not critically contradict the biomechanical models in the case of real branching patterns, though the model calculations described the contradiction between da Vinci's rule and the biomechanical models. The field data for Fagus crenata fit the uniform stress model best, indicating that stress uniformity is the key constraint of branch morphology in Fagus crenata rather than elastic similarity or da Vinci's rule. On the other hand, mechanical constraints are not necessarily significant in the morphology of Abies homolepis branches, depending on the number of daughter branches. Rather, these branches were often in agreement with da Vinci's rule. PMID:24714065

Tree branching: Leonardo da Vinci's rule versus biomechanical models.

PubMed

Minamino, Ryoko; Tateno, Masaki

2014-01-01

This study examined Leonardo da Vinci's rule (i.e., the sum of the cross-sectional area of all tree branches above a branching point at any height is equal to the cross-sectional area of the trunk or the branch immediately below the branching point) using simulations based on two biomechanical models: the uniform stress and elastic similarity models. Model calculations of the daughter/mother ratio (i.e., the ratio of the total cross-sectional area of the daughter branches to the cross-sectional area of the mother branch at the branching point) showed that both biomechanical models agreed with da Vinci's rule when the branching angles of daughter branches and the weights of lateral daughter branches were small; however, the models deviated from da Vinci's rule as the weights and/or the branching angles of lateral daughter branches increased. The calculated values of the two models were largely similar but differed in some ways. Field measurements of Fagus crenata and Abies homolepis also fit this trend, wherein models deviated from da Vinci's rule with increasing relative weights of lateral daughter branches. However, this deviation was small for a branching pattern in nature, where empirical measurements were taken under realistic measurement conditions; thus, da Vinci's rule did not critically contradict the biomechanical models in the case of real branching patterns, though the model calculations described the contradiction between da Vinci's rule and the biomechanical models. The field data for Fagus crenata fit the uniform stress model best, indicating that stress uniformity is the key constraint of branch morphology in Fagus crenata rather than elastic similarity or da Vinci's rule. On the other hand, mechanical constraints are not necessarily significant in the morphology of Abies homolepis branches, depending on the number of daughter branches. Rather, these branches were often in agreement with da Vinci's rule.

A tree canopy height delineation method based on Morphological Reconstruction—Open Crown Decomposition

NASA Astrophysics Data System (ADS)

Liu, Q.; Jing, L.; Li, Y.; Tang, Y.; Li, H.; Lin, Q.

2016-04-01

For the purpose of forest management, high resolution LIDAR and optical remote sensing imageries are used for treetop detection, tree crown delineation, and classification. The purpose of this study is to develop a self-adjusted dominant scales calculation method and a new crown horizontal cutting method of tree canopy height model (CHM) to detect and delineate tree crowns from LIDAR, under the hypothesis that a treetop is radiometric or altitudinal maximum and tree crowns consist of multi-scale branches. The major concept of the method is to develop an automatic selecting strategy of feature scale on CHM, and a multi-scale morphological reconstruction-open crown decomposition (MRCD) to get morphological multi-scale features of CHM by: cutting CHM from treetop to the ground; analysing and refining the dominant multiple scales with differential horizontal profiles to get treetops; segmenting LiDAR CHM using watershed a segmentation approach marked with MRCD treetops. This method has solved the problems of false detection of CHM side-surface extracted by the traditional morphological opening canopy segment (MOCS) method. The novel MRCD delineates more accurate and quantitative multi-scale features of CHM, and enables more accurate detection and segmentation of treetops and crown. Besides, the MRCD method can also be extended to high optical remote sensing tree crown extraction. In an experiment on aerial LiDAR CHM of a forest of multi-scale tree crowns, the proposed method yielded high-quality tree crown maps.

Phototropic growth in a reef flat acroporid branching coral species.

PubMed

Kaniewska, Paulina; Campbell, Paul R; Fine, Maoz; Hoegh-Guldberg, Ove

2009-03-01

Many terrestrial plants form complex morphological structures and will alter these growth patterns in response to light direction. Similarly reef building corals have high morphological variation across coral families, with many species also displaying phenotypic plasticity across environmental gradients. In particular, the colony geometry in branching corals is altered by the frequency, location and direction of branch initiation and growth. This study demonstrates that for the branching species Acropora pulchra, light plays a key role in axial polyp differentiation and therefore axial corallite development--the basis for new branch formation. A. pulchra branches exhibited a directional growth response, with axial corallites only developing when light was available, and towards the incident light. Field experimentation revealed that there was a light intensity threshold of 45 micromol m(-2) s(-1), below which axial corallites would not develop and this response was blue light (408-508 nm) dependent. There was a twofold increase in axial corallite growth above this light intensity threshold and a fourfold increase in axial corallite growth under the blue light treatment. These features of coral branch growth are highly reminiscent of the initiation of phototropic branch growth in terrestrial plants, which is directed by the blue light component of sunlight.

Single-crystalline self-branched anatase titania nanowires for dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Li, Zhenquan; Yang, Huang; Wu, Fei; Fu, Jianxun; Wang, Linjun; Yang, Weiguang

2017-03-01

The morphology of the anatase titania plays an important role in improving the photovoltaic performance in dye-sensitized solar cells. In this work, single-crystalline self-branched anatase TiO2 nanowires have been synthesized by hydrothermal method using TBAH and CTAB as morphology controlling agents. The obtained self-branched TiO2 nanowires dominated by a large percentage of (010) facets. The photovoltaic conversion efficiency (6.37%) of dye-sensitized solar cell (DSSC) based on the self-branched TiO2 nanowires shows a significant improvement (26.6%) compared to that of P25 TiO2 (5.03%). The enhanced performance of the self-branched TiO2 nanowires-based DSSC is due to heir large percent of exposed (010) facets which have strong dye adsorption capacity and effective charge transport of the self-branched 1D nanostructures.

Morphology of blends of linear and long-chain-branched polyethylenes in the solid state: A study by SANS, SAXS, and DSC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wignall, G.D.; Londono, J.D.; Lin, J.S.

1995-04-24

Differential scanning calorimetry (DSC), small-angle neutron scattering (SANS), and X-ray scattering (SAXS) have been used to investigate the solid-state morphology of blends of linear (high density) and long-chain-branched (low-density) polyethylenes (HDPE/LDPE). The blends are homogeneous in the melt, as previously demonstrated by SANS using the contrast obtained by deuterating the linear polymer. However, due to the structural and melting point differences ({approximately} 20 C) between HDPE and LDPE, the components may phase segregate on slow cooling (0.75 C/min). For high concentrations ({phi} {ge} 0.5) of HDPE, relatively high rates of crystallization of the linear component lead to the formation ofmore » separate stacks of HDPE and LDPE lamellae, as indicated by two-peak SAXS curves. For predominantly branched blends, the difference in crystallization rate of the components becomes smaller and only one SAXS peak is observed, indicating that the two species are in the same lamellar stack. Moreover, the phases no longer consist of the pure component and the HDPE lamellae contain up to 15--20% LDPE (and vice versa). Rapid quenching into dry ice/2-propanol ({minus}78 C) produces only one SAXS peak (and hence one lamellar stack) over the whole concentration range. The blends show extensive cocrystallization, along with a tendency for the branched material to be preferentially located in the amorphous interlamellar regions. For high concentrations ({phi} > 0.5) of HDPE-D, the overall scattering length density (SLD) is high and the excess concentration of LDPE between the lamellae enhances the SLD contrast between the crystalline and amorphous phases. Thus, the interlamellar spacing (long period) is clearly visible in the SANS pattern. The blend morphology is a strong function of the quenching rate, and samples quenched less rapidly (e.g., into water at 23 C) are similar to slowly cooled blends.« less

Duration of the Early Galactic Formation Epoch: HST Photometry for Red-Horizontal Branch Clusters in the Outer Halo

NASA Astrophysics Data System (ADS)

Hesser, J. E.; Stetson, P. B.; McClure, R. D.; van den Bergh, S.; Bolte, M.; Harris, W. E.; van den Berg, D. A.; Bell, R. A.; Fahlman, G. G.; Richer, H. B.; Bond, H. E.

1997-12-01

Last year we presented evidence from HST photometry of the low-metallicity cluster NGC 2419 (M_V = -9.5, R_⊙ ~ 90 kpc, [Fe/H] = -2.2) that globular cluster formation began at essentially the same time throughout a region of the Galactic halo now almost 200 kpc in diameter (Harris et al. 1997 AJ 114, 1030). We now turn to the time spread of halo formation, with the ultimate aim of addressing the relative roles of mergers over the first 4 or more Gyrs (Searle & Zinn 1978, ApJ, 225, 357; Lee, Demarque & Zinn 1994 ApJ, 423, 248) versus models favoring a rapid collapse (Eggen, Lynden-Bell & Sandage 1962, ApJ, 236, 748; Stetson, VandenBerg & Bolte 1996, PASP, 108, 560), or some combination of those and other processes. We provide the first reliable measurements from the giant branch through the main-sequence turnoffs of red-horizontal-branch clusters in the outer halo, which are frequently postulated to be younger than most other globular clusters. From WFPC2 F555W (`V') and F814W (`I') photometry for Pal 3 (M_V = -5.2, R_⊙ ~ 87 kpc), Pal 4 (M_V = -5.8, R_⊙ ~ 98 kpc), and Eridanus (M_V = -4.8, R_⊙ ~ 78 kpc), all with [Fe/H] ~ -1.5, we estimate their relative ages by making differential comparisons among them and with respect to inner-halo objects of, presumably, comparable chemical compositions. It seems likely at this stage of our analysis that (a) the three clusters are the same age to our measurement precision of ~ 1 Gyr, and, (b) the CMDs of all three outer halo clusters differ from those of M 3 and M 5 (our template clusters of similar metallicity), in the sense that the outer halo clusters are younger by ~ 3 Gyr, or they are ~ 0.5 dex more metal-rich than currently thought. Large uncertainties in chemical compositions (He, [alpha /Fe], [CNO/Fe]) for outer halo and template clusters alike mask the true interpretation.

Quantifying Morphological Parameters of the Terminal Branching Units in a Mouse Lung by Phase Contrast Synchrotron Radiation Computed Tomography

PubMed Central

Hwang, Jeongeun; Kim, Miju; Kim, Seunghwan; Lee, Jinwon

2013-01-01

An effective technique of phase contrast synchrotron radiation computed tomography was established for the quantitative analysis of the microstructures in the respiratory zone of a mouse lung. Heitzman’s method was adopted for the whole-lung sample preparation, and Canny’s edge detector was used for locating the air-tissue boundaries. This technique revealed detailed morphology of the respiratory zone components, including terminal bronchioles and alveolar sacs, with sufficiently high resolution of 1.74 µm isotropic voxel size. The technique enabled visual inspection of the respiratory zone components and comprehension of their relative positions in three dimensions. To check the method’s feasibility for quantitative imaging, morphological parameters such as diameter, surface area and volume were measured and analyzed for sixteen randomly selected terminal branching units, each consisting of a terminal bronchiole and a pair of succeeding alveolar sacs. The four types of asymmetry ratios concerning alveolar sac mouth diameter, alveolar sac surface area, and alveolar sac volume are measured. This is the first ever finding of the asymmetry ratio for the terminal bronchioles and alveolar sacs, and it is noteworthy that an appreciable degree of branching asymmetry was observed among the alveolar sacs at the terminal end of the airway tree, despite the number of samples was small yet. The series of efficient techniques developed and confirmed in this study, from sample preparation to quantification, is expected to contribute to a wider and exacter application of phase contrast synchrotron radiation computed tomography to a variety of studies. PMID:23704918

Chemical composition of stars in globular clusters: M5, M13, and M3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pilachowski, C.A.; Wallerstein, G.; Myckky Leep, E.

The composition of giant stars in the globular clusters M3, M5, and M13 have been determined by detailed model atmosphere analysis; the average iron deficiencies relative to the Sun are -1.55, -1.33, and -1.42, respectively. Oxygen is overabundant relative to iron in M3 and M5 but not in M13. Differences in the oxygen abundance can account for variation in horizontal-branch morphology; clusters of intermediate metallicity with high oxygen have red horizontal-branch stars, and those with low oxygen have only blue horizontal-branch stars Z/sub cno/ is the second abundance parameter.

Thermoelectric effects in disordered branched nanowires

NASA Astrophysics Data System (ADS)

Roslyak, Oleksiy; Piriatinskiy, Andrei

2013-03-01

We shall develop formalism of thermal and electrical transport in Si1 - x Gex and BiTe nanowires. The key feature of those nanowires is the possibility of dendrimer type branching. The branching tree can be of size comparable to the short wavelength of phonons and by far smaller than the long wavelength of conducting electrons. Hence it is expected that the branching may suppress thermal and let alone electrical conductance. We demonstrate that the morphology of branches strongly affects the electronic conductance. The effect is important to the class of materials known as thermoelectrics. The small size of the branching region makes large temperature and electrical gradients. On the other hand the smallness of the region would allow the electrical transport being ballistic. As usual for the mesoscopic systems we have to solve macroscopic (temperature) and microscopic ((electric potential, current)) equations self-consistently. Electronic conductance is studied via NEGF formalism on the irreducible electron transfer graph. We also investigate the figure of merit ZT as a measure of the suppressed electron conductance.

Gravity-dependent regulation of red light induced moss protonemata branching and gametophore bud formation

NASA Astrophysics Data System (ADS)

Ripetskyj, R. T.; Kit, N. A.

Isolated leafy shoots of the moss Pottia intermedia positioned horizontally on the agar surface in vertically oriented petri dishes regenerate unbranching negatively gravitropic protonemata on upper side of the regenerant. Gravity determines the site of regeneration not the process itself. White light of low intensity unsufficient to induce positive phototropism of dark-grown protonemata can, however, provoke their branching and gametophore bud formation (Ripetskyj et al., 1998; 1999). The presented experiments have been carried out with red light in Biological Research in Canisters/Light Emitting Diode (BRIC/LED) hardware developed at Kennedy Space Center, USA. Seven-day-old dark-grown negatively gravitropic secondary P. intermedia protonemata were positioned differently with respect to gravity vector and to the source of red light of low, 1 or 2 μ mol\\cdot m-2\\cdot s-1, intensities. The light induced intensive branching of the protonemata and gametophore bud formation initiation site of both processes as well as the direction of growth of branches and buds being depent on the position of protonemata with respect to gravity and light vectors. Vertically positioned, i.e. ungravistimulated, dark grown protonemata illuminated from one side with red light of 2 μ mol\\cdot m-2\\cdot s-1 intensity produced 96,9 ± 2,2% of side branches and buds growing directly towards the light source from the lit protonema side. Horizontally disposed protonemata irradiated from below with red light of the same intensity regenerate 31,7 ± 3,9% of branches and buds on the upper, i.e. shaded protonemata side, the upward growth of which should undoubtedly be determined by gravity. In vertically disposed protonemata illuminated with red light of 1 μ mol\\cdot m-2\\cdot s-1 intensity from aside 31,9 ± 5,5% of side branches and buds arised on shaded protonema side and grew away from the light. Illumination of the protonemata in horizontal position from below increased the number of

Flash Mixing on the White-Dwarf Cooling Curve: Understanding Hot Horizontal Branch Anomalies in NGC 2808

NASA Technical Reports Server (NTRS)

Brown, Thomas M.; Sweigart, Allen V.; Lanz, Thierry; Landsman, Wayne B.; Hubeny, Ivan; Fisher, Richard R. (Technical Monitor)

2001-01-01

We present an ultraviolet color-magnitude diagram (CMD) spanning the hot horizontal branch (HB), blue straggler, and white dwarf populations of the globular cluster NGC 2808. These data, obtained with the Space Telescope Imaging Spectrograph (STIS), demonstrate that NGC 2808 harbors a significant population of hot subluminous HB stars, an anomaly only previously reported for the globular cluster omega Cen. Our theoretical modeling indicates that the location of these subluminous stars in the CMD, as well as the high temperature gap along the HB of NGC 2808, can be explained if these stars underwent a late helium-core flash while descending the white dwarf cooling curve. We show that the convective zone produced by such a late helium flash will penetrate into the hydrogen envelope, thereby mixing hydrogen into the hot helium-burning interior, where it is rapidly consumed. This phenomenon is analogous to the "born again" scenario for producing hydrogen-deficient stars following a late helium-shell flash. The flash mixing of the envelope greatly enhances the envelope helium and carbon abundances that, in turn, leads to a discontinuous increase in the HB effective temperatures. We argue that the hot HB gap is associated with this theoretically predicted dichotomy in the HB properties. Moreover, the changes in the emergent spectral energy distribution caused by these abundance changes are primarily responsible for explaining the hot subluminous HB stars. Although further evidence is needed to confirm that a late helium-core flash can account for the subluminous HB stars and the hot HB gap, we demonstrate that an understanding of these stars requires the use of appropriate theoretical models for their evolution, atmospheres, and spectra.

Allometry of root branching and its relationship to root morphological and functional traits in three range grasses.

PubMed

Arredondo, J Tulio; Johnson, Douglas A

2011-11-01

The study of proportional relationships between size, shape, and function of part of or the whole organism is traditionally known as allometry. Examination of correlative changes in the size of interbranch distances (IBDs) at different root orders may help to identify root branching rules. Root morphological and functional characteristics in three range grasses {bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) Löve], crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult.×A. cristatum (L.) Gaert.], and cheatgrass (Bromus tectorum L.)} were examined in response to a soil nutrient gradient. Interbranch distances along the main root axis and the first-order laterals as well as other morphological and allocation root traits were determined. A model of nutrient diffusivity parameterized with root length and root diameter for the three grasses was used to estimate root functional properties (exploitation efficiency and exploitation potential). The results showed a significant negative allometric relationship between the main root axis and first-order lateral IBD (P ≤ 0.05), but only for bluebunch wheatgrass. The main root axis IBD was positively related to the number and length of roots, estimated exploitation efficiency of second-order roots, and specific root length, and was negatively related to estimated exploitation potential of first-order roots. Conversely, crested wheatgrass and cheatgrass, which rely mainly on root proliferation responses, exhibited fewer allometric relationships. Thus, the results suggested that species such as bluebunch wheatgrass, which display slow root growth and architectural root plasticity rather than opportunistic root proliferation and rapid growth, exhibit correlative allometry between the main axis IBD and morphological, allocation, and functional traits of roots.

Bicarbonate refractory QRS prolongation and left bundle-branch block following escitalopram and lamotrigine overdose: A case report and literature review of toxic left bundle-branch block.

PubMed

Farkas, A N; Marcott, M; Yanta, J H; Pizon, A F

2018-05-02

Toxic prolongation of the QRS interval most often results from blockade of cardiac voltage-gated sodium channels and manifests on electrocardiogram with a right bundle-branch block-like morphology. Rarely, a left bundle-branch block (LBBB) morphology has been reported. We report a case of transient LBBB resultant from ingestion of lamotrigine and citalopram which was refractory to sodium bicarbonate therapy and eventually resolved spontaneously. Cases of toxic LBBB are less likely to respond to bicarbonate therapy, suggesting that this finding is due to a mechanism other than sodium channel blockade. © 2018 John Wiley & Sons Ltd.

Clear Evidence for the Presence of Second-generation Asymptotic Giant Branch Stars in Metal-poor Galactic Globular Clusters

NASA Astrophysics Data System (ADS)

García-Hernández, D. A.; Mészáros, Sz.; Monelli, M.; Cassisi, S.; Stetson, P. B.; Zamora, O.; Shetrone, M.; Lucatello, S.

2015-12-01

Galactic globular clusters (GCs) are known to host multiple stellar populations: a first generation (FG) with a chemical pattern typical of halo field stars and a second generation (SG) enriched in Na and Al and depleted in O and Mg. Both stellar generations are found at different evolutionary stages (e.g., the main-sequence turnoff, the subgiant branch, and the red giant branch (RGB)). The non detection of SG asymptotic giant branch (AGB) stars in several metal-poor ([Fe/H] < -1) GCs suggests that not all SG stars ascend the AGB phase, and that failed AGB stars may be very common in metal-poor GCs. This observation represents a serious problem for stellar evolution and GC formation/evolution theories. We report fourteen SG-AGB stars in four metal-poor GCs (M13, M5, M3, and M2) with different observational properties: horizontal branch (HB) morphology, metallicity, and age. By combining the H-band Al abundances obtained by the Apache Point Observatory Galactic Evolution Experiment survey with ground-based optical photometry, we identify SG Al-rich AGB stars in these four GCs and show that Al-rich RGB/AGB GC stars should be Na-rich. Our observations provide strong support for present, standard stellar models, i.e., without including a strong mass-loss efficiency, for low-mass HB stars. In fact, current empirical evidence is in agreement with the predicted distribution of FG and SG stars during the He-burning stages based on these standard stellar models.

Fractal branching organizations of Ediacaran rangeomorph fronds reveal a lost Proterozoic body plan.

PubMed

Hoyal Cuthill, Jennifer F; Conway Morris, Simon

2014-09-09

The branching morphology of Ediacaran rangeomorph fronds has no exact counterpart in other complex macroorganisms. As such, these fossils pose major questions as to growth patterns, functional morphology, modes of feeding, and adaptive optimality. Here, using parametric Lindenmayer systems, a formal model of rangeomorph morphologies reveals a fractal body plan characterized by self-similar, axial, apical, alternate branching. Consequent morphological reconstruction for 11 taxa demonstrates an adaptive radiation based on 3D space-filling strategies. The fractal body plan of rangeomorphs is shown to maximize surface area, consistent with diffusive nutrient uptake from the water column (osmotrophy). The enigmas of rangeomorph morphology, evolution, and extinction are resolved by the realization that they were adaptively optimized for unique ecological and geochemical conditions in the late Proterozoic. Changes in ocean conditions associated with the Cambrian explosion sealed their fate.

The surgical anatomy of the infrapatellar branch of the saphenous nerve in relation to incisions for anteromedial knee surgery.

PubMed

Kerver, A L A; Leliveld, M S; den Hartog, D; Verhofstad, M H J; Kleinrensink, G J

2013-12-04

Iatrogenic injury to the infrapatellar branch of the saphenous nerve is a common complication of surgical approaches to the anteromedial side of the knee. A detailed description of the relative anatomic course of the nerve is important to define clinical guidelines and minimize iatrogenic damage during anterior knee surgery. In twenty embalmed knees, the infrapatellar branch of the saphenous nerve was dissected. With use of a computer-assisted surgical anatomy mapping tool, safe and risk zones, as well as the location-dependent direction of the nerve, were calculated. The location of the infrapatellar branch of the saphenous nerve is highly variable, and no definite safe zone could be identified. The infrapatellar branch runs in neither a purely horizontal nor a vertical course. The course of the branch is location-dependent. Medially, it runs a nearly vertical course; medial to the patellar tendon, it has a -45° distal-lateral course; and on the patella and patellar tendon, it runs a close to horizontal-lateral course. Three low risk zones for iatrogenic nerve injury were identified: one is on the medial side of the knee, at the level of the tibial tuberosity, where a -45° oblique incision is least prone to damage the nerves, and two zones are located medial to the patellar apex (cranial and caudal), where close to horizontal incisions are least prone to damage the nerves. The infrapatellar branch of the saphenous nerve is at risk for iatrogenic damage in anteromedial knee surgery, especially when longitudinal incisions are made. There are three low risk zones for a safer anterior approach to the knee. The direction of the infrapatellar branch of the saphenous nerve is location-dependent. To minimize iatrogenic damage to the nerve, the direction of incisions should be parallel to the direction of the nerve when technically possible. These findings suggest that iatrogenic damage of the infrapatellar branch of the saphenous nerve can be minimized in anteromedial

The morphology of blends of linear and branched polyethylenes by small-angle neutron and x-ray scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Londono, J.D.; Wignall, G.D.; Lin, J.S.

1995-12-31

The solid-state morphology and liquid-state homogeneity of blends of high-density polyethylene (HDPE) and low-density polyethylene (LDPE) were investigated by small-angle neutron and x-ray scattering (SANS and SAXS). The solid state morphology was investigated as a function of composition and cooling rate from the melt. After slow cooling, the evidence indicated that the mixtures were either completely (HDPE-rich blends) or almost completely (LDPE-rich blends) phase separated into separate HDPE and LDPE lamellae over the whole compositional range. In contrast, for rapidly quenched blends the components are extensively co-crystallized for all concentrations, though the SANS data indicated that the branched component hadmore » a tendency to be preferentially located in the inter-lamellar regions. In the liquid state, the blends were homogeneous at all compositions, showing that the solid state morphology is not determined by the melt structure, but is a function of the crystallization kinetics. Further evidence for blend homogeneity in the liquid is presented. In particular the authors examine the hypothesis that a phase separated mixture might give a scattering pattern similar to a homogeneous blend if the domain sizes were larger than the maximum spatial resolution of the SANS experiment (D > 2{pi}/Q{sub min} {approximately} 2,000 {angstrom}). In this scenario, the differential scattering cross section d{Sigma}/d{Omega}(Q) {approximately} Q{sup {minus}2}, though phase separation decreases the cross section in this Q-range with respect to the homogeneous blend. For HDPE/LDPE blends in the melt, this decrease in intensity was not observed, thus ruling out the possibility of phase separation.« less

The Branching Pattern of the Brachiocephalic Trunk in the Donkey (Equus asinus).

PubMed

Akbari, G; Asadiahranjani, B; Goodarzi, N; Shokrollahi, S

2017-08-01

Donkeys are a member of the horse family (Equidae) and share a common ancestor. However, in morphological terms, donkeys and horses are regarded as two separate subgenus. Given variations in the branching pattern of the brachiocephalic trunk (BCT) in different species of animals and the use of donkeys in anatomy courses at colleges of veterinary medicine, we conducted this study in order to investigate the branching patterns of BCT and to describe detailed morphological information regarding donkeys. Seventeen mature donkeys were examined following euthanasia by exsanguination from the common carotid artery under general anaesthesia. Thirteen donkeys were embalmed and injected with coloured latex from BCT origin for better visualization of vessels. Four other donkeys were freshly studied without the embalming procedure. In all cases, the BCT was the only branch of the aortic arch and branched into the left subclavian (LSb) artery, the right costocervical trunk, the right subclavian (RSb) artery and the bicarotid trunk. The main branching pattern of the RSb was the costocervical trunk, the vertebral artery, the internal thoracic artery and the superficial cervical artery. The deep cervical artery branched from the costocervical trunk. The major branching pattern of the LSb was the vertebral artery, the internal thoracic artery and the superficial cervical artery. In donkeys, the external thoracic artery branches from the internal thoracic artery. Results obtained from this study indicate that BCT branching in donkeys has some similarities and differences as compared to that in horses and in the Caspian miniature horse. © 2017 Blackwell Verlag GmbH.

A tree branch instead of a ligature: an unusual accidental hanging.

PubMed

Vadysinghe, Amal Nishantha; Sivasubramanium, Murugupillai; Jayasooriya, Rankothge Pemasiri

2017-12-01

A unique case of accidental hanging due to compression of the neck of an adult by the branches of a coffee tree is reported. The decedent was a 42-year-old male who was found dead in a semi prone position on a slope. His neck was lodged in a wedge formed by two branches of a coffee tree, with his legs angled downwards on the slope. Autopsy revealed two friction abrasions located horizontally on either side of the front of the neck, just above the larynx. The findings were compatible with compression of the neck by the branches of the tree, with the body weight of the decedent contributing to compression. Subsequent complete autopsy examination confirmed the cause of death as hanging. Following an inquest the death was ruled to be accidental.

Anatomical study of the superficial temporal branches of the auriculotemporal nerve: Application to surgery and other invasive treatments to the temporal region.

PubMed

Iwanaga, Joe; Watanabe, Koichi; Saga, Tsuyoshi; Fisahn, Christian; Oskouian, Rod J; Tubbs, R Shane

2017-03-01

The auriculotemporal nerve (ATN) is one of the branches of the mandibular division of the trigeminal nerve, which gives rise to many branches to the retromandibular and temporal regions. Of these, the superficial temporal branch can occasionally be the cause of migraine headaches and auriculotemporal neuralgia. The purpose of this study was to elucidate the anatomy of the superficial temporal branch, which has never been described in detail. A total of 14 sides of cadaveric heads were used for this study. The number of superficial temporal branch was counted, and the horizontal and vertical distances from the middle of the tragus to the branching point were measured. Three of 14 sides had two main trunks, and 11 sides had one main trunk. Each of the duplicated ATN had already branches into two main trunks as they left the retromandibular space. The number of superficial temporal branches ranged from two to seven. The vertical and horizontal distances from the middle of the tragus to the branching point of the superficial temporal branch ranged from 6.19 to 25.65 mm and from 3.45 to 11.88 mm, respectively. The communicating branches occasionally formed a loop or so-called "ansa," and a double ansa was identified in one case. These data can provide surgeons a better view of the course of these distant branches, so that skin incisions can be better planned. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Level of helium enhancement among M3's horizontal branch stars

NASA Astrophysics Data System (ADS)

Valcarce, A. A. R.; Catelan, M.; Alonso-García, J.; Contreras Ramos, R.; Alves, S.

2016-05-01

Context. The color and luminosity distribution of horizontal branch (HB) stars in globular clusters (GCs) are sensitive probes of the original helium abundances of those clusters. In this sense, recently the distributions of HB stars in GC color-magnitude diagrams (CMDs) have been extensively used as indicators of possible variations in the helium content Y among the different generations of stars within individual GCs. However, recent analyses based on visual and near-ultraviolet (UV) CMDs have provided conflicting results. Aims: To clarify the situation, we address the optimum ranges of applicability (in terms of the Teff range covered by the HB stars) for visual and near-UV CMDs, as far as application of this "HB Y test" goes. Methods: We considered both Strömgren and Hubble Space Telescope (HST) bandpasses. In particular, we focus on the F336W filter of the HST, but also discuss several bluer UV bandpasses, such as F160BW, F255W, and F300W. Using the Princeton-Goddard-PUC (PGPUC) code, we computed a large set of zero-age HB (ZAHB) loci and HB evolutionary models for masses ranging from MHB = 0.582 to 0.800 M⊙, assuming an initial helium abundance Y = 0.246, 0.256, and 0.266, with a global metallicity Z = 0.001. The results of these calculations were compared against the observations of M3 (NGC 5272), with special attention on the y vs. (b - y) and F336W vs. (F336W-F555W) CMDs. Results: Our results indicate that, from an evolutionary perspective, the distributions of HB stars in the y vs. (b - y) plane can be a reliable indicator of the He content in cool blue HB (BHB) stars, particularly when a differential comparison between blue and red HB stars is carried out in the range Teff ≲ 8300 K. Conversely, we demonstrate that CMDs using the F336W filter have a much less straightforward interpretation at the cool end of the BHB because the distributions of HB stars in the F336W vs. (F336W-F555W) plane, for instance, are affected by a triple degeneracy effect. In

The effect of Pb addition on the morphology of CdSe quantum dot

NASA Astrophysics Data System (ADS)

Kim, Young-Kuk; Cho, Young-Sang; Chung, Kookchae; Choi, Chul-Jin

2010-08-01

CdSe quantum dots had been synthesized with a hot injection method. It was shown that the addition of Pb ions in the initial precursor solution changed the morphology of CdSe nanocrystals from slightly prolate ellipsoid to branched rod. Photoluminescence (PL) of the branched nanocrystals showed rapid depression of emission intensity due to the morphological development to the branched nanocrystal induced by Pb addition. Low temperature PL spectrum indicated that the surface recombination of charge carrier resulted in the large depression of emission from the branched nanocrystal.

Dielectric response of branched copper phthalocyanine

NASA Astrophysics Data System (ADS)

Hamam, Khalil J.; Al-Amar, Mohammad M.; Mezei, Gellert; Guda, Ramakrishna; Burns, Clement A.

2017-09-01

The dielectric constant of pressed pellets and thin films of branched copper phthalocyanine (CuPc) was investigated as a function of frequency from 0.1 kHz to 1 MHz and temperature from 20 °C to 100 °C. Surface morphology was studied using a scanning electron microscope. The high-frequency values of the dielectric constant of pellets and thin films are ~3.5 and ~5.8, respectively. The response was only weakly dependent on frequency and temperature. The branched structure of the CuPc molecules helped to cancel out the effects of low-frequency polarization mechanisms. A planar delocalized charge system with two-dimensional localization was found using time-resolved photoluminescence measurements.

CORRELATIONS IN HORIZONTAL BRANCH OSCILLATIONS AND BREAK COMPONENTS IN XTE J1701-462 AND GX 17+2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bu, Qing-cui; Chen, Li; Zhang, Liang

2015-01-20

We studied the horizontal branch oscillations (HBO) and the band-limited components observed in the power spectra of the transient neutron star low-mass X-ray binary XTE J1701-462 and the persistent ''Sco-like'' Z source GX 17+2. These two components were studied based on the state-resolved spectra. We found that the frequencies of XTE J1701-462 lie on the known correlations (WK and PBK), showing consistency with other types of X-ray binaries (black holes, atoll sources, and millisecond X-ray pulsars). However, GX 17+2 is shifted from the WK correlation like other typical Z sources. We suggest that the WK/PBK main track forms a boundarymore » that separates persistent sources from transient sources. The characteristic frequencies of break and HBO are independent of accretion rate in both sources, though it depends on spectral models. We also report the energy dependence of the HBO and break frequencies in XTE J1701-462 and how the temporal properties change with spectral state in XTE J1701-462 and GX 17+2. We studied the correlation between rms at the break and the HBO frequency. We suggest that HBO and break components for both sources probably arise from a similar physical mechanism: Comptonization emission from the corona. These two components could be caused by the same kind of oscillation in a corona with uneven density, and they could be generated from different areas of the corona. We further suggest that different proportions of the Comptonization component in the total flux cause the different distribution between GX 17+2 and XTE J1701-462 in the rms{sub break}-rms{sub HBO} diagram.« less

Structure of the Milky Way stellar halo out to its outer boundary with blue horizontal-branch stars

NASA Astrophysics Data System (ADS)

Fukushima, Tetsuya; Chiba, Masashi; Homma, Daisuke; Okamoto, Sakurako; Komiyama, Yutaka; Tanaka, Masayuki; Tanaka, Mikito; Arimoto, Nobuo; Matsuno, Tadafumi

2018-06-01

We present the structure of the Milky Way stellar halo beyond Galactocentric distances of r = 50 kpc traced by blue horizontal-branch (BHB) stars, which are extracted from the survey data in the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). We select BHB candidates based on (g, r, i, z) photometry, where the z-band is on the Paschen series and the colors that involve the z-band are sensitive to surface gravity. About 450 BHB candidates are identified between r = 50 kpc and 300 kpc, most of which are beyond the reach of previous large surveys, including the Sloan Digital Sky Survey. We find that the global structure of the stellar halo in this range has substructures, which are especially remarkable in the GAMA15H and XMM-LSS fields in the HSC-SSP. We find that the stellar halo can be fitted to a single power-law density profile with an index of α ≃ 3.3 (3.5) with (without) these fields and its global axial ratio is q ≃ 2.2 (1.3). Thus, the stellar halo may be significantly disturbed and be made in a prolate form by halo substructures, perhaps associated with the Sagittarius stream in its extension beyond r ˜ 100 kpc. For a broken power-law model allowing different power-law indices inside/outside a break radius, we obtain a steep power-law slope of α ≃ 5 outside a break radius of ˜100 kpc (200 kpc) for the case with (without) GAMA15H and XMM-LSS. This radius of 200 kpc might be as close as a halo boundary if there is any, although a larger BHB sample is required from further HSC-SSP surveys to increase its statistical significance.

Hot Horizontal-Branch Stars: The Ubiquitous Nature of the ``Jump'' in Strömgren u, Low Gravities, and the Role of Radiative Levitation of Metals

NASA Astrophysics Data System (ADS)

Grundahl, F.; Catelan, M.; Landsman, W. B.; Stetson, P. B.; Andersen, M. I.

1999-10-01

A ``jump'' in the blue horizontal-branch (HB) distribution in the (V, u-y) color-magnitude diagram has recently been detected in the globular cluster (GC) M13 (NGC 6205) by Grundahl and coworkers. Such an effect is morphologically best characterized as a discontinuity in the (u, u-y) locus, with stars in the range 11,500 K<~Teff<~20,000 K deviating systematically from (in the sense of appearing brighter and/or hotter than) canonical zero-age HB models. In this article, we present Strömgren u, y photometry of 14 GCs obtained with three different telescopes (ESO Danish, Nordic Optical Telescope, and the Hubble Space Telescope) and demonstrate that the jump in Strömgren u is present in every GC whose HB extends beyond Teff>~11,500 K, irrespective of metallicity, mixing history on the red giant branch (RGB), or any known parameter characterizing our sample of GCs. We thus suggest that the u jump is a ubiquitous feature, intrinsic to all HB stars hotter than Teff~=11,500 K. We draw a parallel between the ubiquitous nature of the u jump and the well-known problem of low measured gravities among blue HB stars in GCs and in the field. We note that the ``gravity jump'' occurs over the same temperature range as the u jump and also that it occurs in every metal-poor cluster for which gravities have been determined--again irrespective of metallicity, mixing history on the RGB, or any known parameter characterizing the surveyed GCs. Furthermore, we demonstrate that the u jump and the gravity jump are connected on a star-by-star basis. We thus suggest that the two most likely are different manifestations of one and the same physical phenomenon. We present an interpretative framework which may be capable of simultaneously accounting for both the u jump and the gravity jump. Reviewing spectroscopic data for several field blue HB stars, as well as two blue HB stars in NGC 6752, we find evidence that radiative levitation of elements heavier than carbon and nitrogen takes place at

Parotid Branches of the Auriculotemporal Nerve: An Anatomical Study With Implications for Frey Syndrome.

PubMed

Iwanaga, Joe; Fisahn, Christian; Watanabe, Koichi; Bobek, Samuel L; Ogata, Kinuko; Tanoue, Ryuichiro; Kusukawa, Jingo; Oskouian, Rod J; Tubbs, R Shane

2017-01-01

The auriculotemporal nerve is one of the many branches of the mandibular division of the trigeminal nerve. Of these, its superficial temporal branch has been most described. Although the parotid branches, secretomotor fibers to the parotid gland, are well known as the cause of Frey syndrome, there have been almost no descriptions of their anatomy. In this study, the authors dissected the parotid branches of the auriculotemporal nerve to elucidate their anatomy. A total of 10 sides from 7 adult and embalmed cadaver heads were used in this study. The specimens were derived from 3 males and 4 females, the age of cadavers at death ranged from 65 to 92 years old. Measurements included their diameter and the distance of their branching point from the main trunk of the auriculotemporal nerve from the middle of the tragus. Three of 10 sides had 2 parotid branches and 7 sides were found to have 1 parotid branch. The vertical distance between middle of the tragus to branching point of the parotid branch ranged from 1.79 to 16.17 mm. The horizontal distance between middle of the tragus to branching point of the parotid branch ranged from 3.03 to 12.62 mm. The diameter of the parotid branch ranged from 0.31 to 0.49 mm. An improved knowledge of the parotid branch of the auriculotemporal nerve might decrease injury to these structures with the potential for postoperative.

Spontaneous Age-Related Neurite Branching in C. elegans

PubMed Central

Tank, Elizabeth M. H.; Rodgers, Kasey E.; Kenyon, Cynthia

2011-01-01

The analysis of morphological changes that occur in the nervous system during normal aging could provide insight into cognitive decline and neurodegenerative disease. Previous studies have suggested that the nervous system of C. elegans maintains its structural integrity with age despite the deterioration of surrounding tissues. Unexpectedly, we observed that neurons in aging animals frequently displayed ectopic branches, and that the prevalence of these branches increased with time. Within age-matched populations, the branching of mechnosensory neurons correlated with decreased response to light touch and decreased mobility. The incidence of branching was influenced by two pathways that can affect the rate of aging, the Jun kinase pathway and the insulin/IGF-1 pathway. Loss of Jun kinase signaling, which slightly shortens lifespan, dramatically increased and accelerated the frequency of neurite branching. Conversely, inhibition of the daf-2 insulin/IGF-1-like signaling pathway, which extends lifespan, delayed and suppressed branching, and this delay required DAF-16/FOXO activity. Both JNK-1 and DAF-16 appeared to act within neurons in a cell-autonomous manner to influence branching, and, through their tissue-specific expression, it was possible to disconnect the rate at which branching occurred from the overall rate of aging of the animal. Old age has generally been associated with the decline and deterioration of different tissues, except in the case of tumor cell growth. To our knowledge, this is the first indication that aging can potentiate another form of growth, the growth of neurite branches, in normal animals. PMID:21697377

Anatomical medial surfaces with efficient resolution of branches singularities.

PubMed

Gil, Debora; Vera, Sergio; Borràs, Agnés; Andaluz, Albert; González Ballester, Miguel A

2017-01-01

Medial surfaces are powerful tools for shape description, but their use has been limited due to the sensibility of existing methods to branching artifacts. Medial branching artifacts are associated to perturbations of the object boundary rather than to geometric features. Such instability is a main obstacle for a confident application in shape recognition and description. Medial branches correspond to singularities of the medial surface and, thus, they are problematic for existing morphological and energy-based algorithms. In this paper, we use algebraic geometry concepts in an energy-based approach to compute a medial surface presenting a stable branching topology. We also present an efficient GPU-CPU implementation using standard image processing tools. We show the method computational efficiency and quality on a custom made synthetic database. Finally, we present some results on a medical imaging application for localization of abdominal pathologies. Copyright © 2016 Elsevier B.V. All rights reserved.

Branching habit and the allocation of reproductive resources in conifers.

PubMed

Leslie, Andrew B

2012-09-01

Correlated relationships between branch thickness, branch density, and twig and leaf size have been used extensively to study the evolution of plant canopy architecture, but fewer studies have explored the impact of these relationships on the allocation of reproductive resources. This study quantifies pollen cone production in conifers, which have similar basic reproductive biology but vary dramatically in branching habit, in order to test how differences in branch diameter influence pollen cone size and the density with which they are deployed in the canopy. Measurements of canopy branch density, the number of cones per branch and cone size were used to estimate the amount of pollen cone tissues produced by 16 species in three major conifer clades. The number of pollen grains produced was also estimated using direct counts from individual pollen cones. The total amount of pollen cone tissues in the conifer canopy varied little among species and clades, although vegetative traits such as branch thickness, branch density and pollen cone size varied over several orders of magnitude. However, branching habit controls the way these tissues are deployed: taxa with small branches produce small pollen cones at a high density, while taxa with large branches produce large cones relatively sparsely. Conifers appear to invest similar amounts of energy in pollen production independent of branching habit. However, similar associations between branch thickness, branch density and pollen cone size are seen across conifers, including members of living and extinct groups not directly studied here. This suggests that reproductive features relating to pollen cone size are in large part a function of the evolution of vegetative morphology and branching habit.

Branching habit and the allocation of reproductive resources in conifers

PubMed Central

Leslie, Andrew B.

2012-01-01

Background and Aims Correlated relationships between branch thickness, branch density, and twig and leaf size have been used extensively to study the evolution of plant canopy architecture, but fewer studies have explored the impact of these relationships on the allocation of reproductive resources. This study quantifies pollen cone production in conifers, which have similar basic reproductive biology but vary dramatically in branching habit, in order to test how differences in branch diameter influence pollen cone size and the density with which they are deployed in the canopy. Methods Measurements of canopy branch density, the number of cones per branch and cone size were used to estimate the amount of pollen cone tissues produced by 16 species in three major conifer clades. The number of pollen grains produced was also estimated using direct counts from individual pollen cones. Key Results The total amount of pollen cone tissues in the conifer canopy varied little among species and clades, although vegetative traits such as branch thickness, branch density and pollen cone size varied over several orders of magnitude. However, branching habit controls the way these tissues are deployed: taxa with small branches produce small pollen cones at a high density, while taxa with large branches produce large cones relatively sparsely. Conclusions Conifers appear to invest similar amounts of energy in pollen production independent of branching habit. However, similar associations between branch thickness, branch density and pollen cone size are seen across conifers, including members of living and extinct groups not directly studied here. This suggests that reproductive features relating to pollen cone size are in large part a function of the evolution of vegetative morphology and branching habit. PMID:22782240

Disruptive selection as a driver of evolutionary branching and caste evolution in social insects.

PubMed

Planqué, R; Powell, S; Franks, N R; van den Berg, J B

2016-11-01

Theory suggests that evolutionary branching via disruptive selection may be a relatively common and powerful force driving phenotypic divergence. Here, we extend this theory to social insects, which have novel social axes of phenotypic diversification. Our model, built around turtle ant (Cephalotes) biology, is used to explore whether disruptive selection can drive the evolutionary branching of divergent colony phenotypes that include a novel soldier caste. Soldier evolution is a recurrent theme in social insect diversification that is exemplified in the turtle ants. We show that phenotypic mutants can gain competitive advantages that induce disruptive selection and subsequent branching. A soldier caste does not generally appear before branching, but can evolve from subsequent competition. The soldier caste then evolves in association with specialized resource preferences that maximize defensive performance. Overall, our model indicates that resource specialization may occur in the absence of morphological specialization, but that when morphological specialization evolves, it is always in association with resource specialization. This evolutionary coupling of ecological and morphological specialization is consistent with recent empirical evidence, but contrary to predictions of classical caste theory. Our model provides a new theoretical understanding of the ecology of caste evolution that explicitly considers the process of adaptive phenotypic divergence and diversification. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Resonant energy transfer and trace-level sensing using branched Ag-rod-supported carbon dots

NASA Astrophysics Data System (ADS)

Nair, Radhika V.; Arya, M.; Vijayan, C.

2018-05-01

We report on the resonant energy transfer in branched Ag rod-supported carbon dots (C-dots) and its applications for the trace-level sensing of highly reactive oxygen species and organic pollutants based on surface plasmon enhanced energy transfer (SPEET) and surface enhanced Raman spectroscopy (SERS). The branched morphology of Ag is found to significantly enhance visible light absorption and thus increases the spectral overlap with C-dot emission. In addition, branched morphology results in the formation of a large number of plasmonic hotspots and efficient propagation of plasmons through the interconnections, as also supported by finite-difference time-domain simulations. Branched Ag-rod—C-dot composite is found to be able to detect 0.02 µM of hydrogen peroxide based on SPEET. The efficient transfer of electrons from C-dots to the Ag rod enhances the SERS efficiency of Ag resulting in an enhancement factor of the order of 108 and enables the composite to detect 10‑10 M of the organic pollutant Rhodamine 6G.

The pivotal role of aristaless in development and evolution of diverse antennal morphologies in moths and butterflies.

PubMed

Ando, Toshiya; Fujiwara, Haruhiko; Kojima, Tetsuya

2018-01-25

Antennae are multi-segmented appendages and main odor-sensing organs in insects. In Lepidoptera (moths and butterflies), antennal morphologies have diversified according to their ecological requirements. While diurnal butterflies have simple, rod-shaped antennae, nocturnal moths have antennae with protrusions or lateral branches on each antennal segment for high-sensitive pheromone detection. A previous study on the Bombyx mori (silk moth) antenna, forming two lateral branches per segment, during metamorphosis has revealed the dramatic change in expression of antennal patterning genes to segmentally reiterated, branch-associated pattern and abundant proliferation of cells contributing almost all the dorsal half of the lateral branch. Thus, localized cell proliferation possibly controlled by the branch-associated expression of antennal patterning genes is implicated in lateral branch formation. Yet, actual gene function in lateral branch formation in Bombyx mori and evolutionary mechanism of various antennal morphologies in Lepidoptera remain elusive. We investigated the function of several genes and signaling specifically in lateral branch formation in Bombyx mori by the electroporation-mediated incorporation of siRNAs or morpholino oligomers. Knock down of aristaless, a homeobox gene expressed specifically in the region of abundant cell proliferation within each antennal segment, during metamorphosis resulted in missing or substantial shortening of lateral branches, indicating its importance for lateral branch formation. aristaless expression during metamorphosis was lost by knock down of Distal-less and WNT signaling but derepressed by knock down of Notch signaling, suggesting the strict determination of the aristaless expression domain within each antennal segment by the combinatorial action of them. In addition, analyses of pupal aristaless expression in antennae with various morphologies of several lepidopteran species revealed that the aristaless expression

The influence of natural head position on the assessment of facial morphology.

PubMed

Woźniak, Krzysztof; Piątkowska, Dagmara; Lipski, Mariusz

2012-01-01

Skeletal relationships play a major part in determining occlusal relationships, and that is why they also affect orthodontic treatment. Facial morphology can be assessed by clinical or radiological methods. Soft tissue analysis of the face is accepted as an integral part of orthodontic diagnosis and treatment planning. The aim of the study was to determine the impact of the inclination between the Frankfort horizontal(FH) and the extracranial horizontal (HOR) lines with the head in the natural position (NHP) on the assessment of facial morphology. Lateral facial photographs of 200 young adult males and females were taken with the head in the natural head position and then analyzed. Each image was rotated in order to position the Frankfort line parallel to the extracranial horizontal line. Twelve landmarks on each of the 400 profile photographs (200 originals,200 processed) were identified, and nine linear measurements and three angular measurements were assessed. The inclination angle between the extracranial horizontal line and the Frankfort horizontal line in the NHP varied from -7.1° to 5.6° (mean -1.20°). Significant correlations were found between the inclination angle FH/HOR and both sagittal and vertical morphology predictors such as the sections N-Sn (r = 0.3737, p = 0.0001), Sn-Gn(r = 0.3231, p = 0.0000), and both facial angles (r = 0.9774, p = 0.0000) and proflle angles (r = 0.9654, p = 0.0000). A comparison of soft tissue measurements determined with reference to the Frankfort horizontal and extracranial horizontal lines with the head in the natural position reveals significant differences

URBAN MORPHOLOGY FOR HOUSTON TO DRIVE MODELS-3/CMAQ AT NEIGHBORHOOD SCALES

EPA Science Inventory

Air quality simulation models applied at various horizontal scales require different degrees of treatment in the specifications of the underlying surfaces. As we model neighborhood scales ( 1 km horizontal grid spacing), the representation of urban morphological structures (e....

HE 0430-2457: a post-merger extremely low-mass pre-white dwarf in a wide binary posing as an extreme horizontal branch star

NASA Astrophysics Data System (ADS)

Vos, Joris; Zorotovic, Monica; Vučković, Maja; Schreiber, Matthias R.; Østensen, Roy

2018-06-01

We report the discovery of HE 0430-2457, the first extremely low-mass pre-white dwarf (ELM pre-WD) in a long period binary (P = 771 ± 3 d). The spectroscopic parameters of the primary are determined to be Teff = 26 200 ± 1500 K and log g = 5.40 ± 0.35, placing it in the region occupied by core He-burning hot subdwarf B stars. By comparing the spectroscopic parameters of the K-type companion to stellar models, and using the mass ratio, the mass of the hot primary is determined to be 0.23 M⊙. Given that this is too low for core He-burning, the primary in HE 0430-2457 is not an extreme horizontal branch (EHB) star but a pre-WD of the ELM type. As the lifetime of ELM pre-WDs in this region of the Hertzsprung Russel diagram populated by EHBs is thought to be very short, they are not considered to be part of the observed EHBs. However, the discovery of this system indicates that the percentage of ELM pre-WDs in the observed EHB population might be higher than previously thought. Binary evolution models indicate that HE 0430-2457 is likely formed by a merger of the inner binary in a hierarchical triple system.

Functional morphology of the hallucal metatarsal with implications for inferring grasping ability in extinct primates.

PubMed

Goodenberger, Katherine E; Boyer, Doug M; Orr, Caley M; Jacobs, Rachel L; Femiani, John C; Patel, Biren A

2015-03-01

Primate evolutionary morphologists have argued that selection for life in a fine branch niche resulted in grasping specializations that are reflected in the hallucal metatarsal (Mt1) morphology of extant "prosimians", while a transition to use of relatively larger, horizontal substrates explains the apparent loss of such characters in anthropoids. Accordingly, these morphological characters-Mt1 torsion, peroneal process length and thickness, and physiological abduction angle-have been used to reconstruct grasping ability and locomotor mode in the earliest fossil primates. Although these characters are prominently featured in debates on the origin and subsequent radiation of Primates, questions remain about their functional significance. This study examines the relationship between these morphological characters of the Mt1 and a novel metric of pedal grasping ability for a large number of extant taxa in a phylogenetic framework. Results indicate greater Mt1 torsion in taxa that engage in hallucal grasping and in those that utilize relatively small substrates more frequently. This study provides evidence that Carpolestes simpsoni has a torsion value more similar to grasping primates than to any scandentian. The results also show that taxa that habitually grasp vertical substrates are distinguished from other taxa in having relatively longer peroneal processes. Furthermore, a longer peroneal process is also correlated with calcaneal elongation, a metric previously found to reflect leaping proclivity. A more refined understanding of the functional associations between Mt1 morphology and behavior in extant primates enhances the potential for using these morphological characters to comprehend primate (locomotor) evolution. © 2014 Wiley Periodicals, Inc.

Does body type really matter? Relating climate change, coral morphology and resiliency

NASA Astrophysics Data System (ADS)

Camp, M.; Shein, K. A.; Foster, K.; Hendee, J. C.

2016-02-01

Average sea temperatures in many tropical regions are rising approximately 1-2˚C per century, and are thought to be a major driver of increased frequency of coral bleaching. However, certain coral morphologies appear to be more resilient to changes in the environment, particularly to sea temperature variations resulting from global climate change. Although branching corals (e.g., Acropora cervicornis, A. palmata) are highly susceptible to coral bleaching, this morphology is commonly used in coral restoration efforts because of its fast growth rate. Massive corals show higher resistance and resilience to elevated temperature events than branching species, but are less common in coral nurseries. The objective of this study was to compare coral resilience among morphology types in Little Cayman, a remote tropical island with <200 inhabitants where it is possible to decouple environmental and anthropogenic stressors. Three morphological groups (branching, intermediary and massive) were surveyed at 17 sites to estimate the percent cover of each group. Temperature profiles were observed at six moorings around the island, allowing for direct comparison between sea surface temperature, sea temperature at the reef depths, and coral cover, per morphology. The relationship between coral morphological coverage and temperature variation at depth was assessed in the context of geographic variation around the island. Understanding the relationship between coral morphology and resilience to temperature variability will enhance current coral restoration practices by identifying which morphologies have the highest chance of long-term survivorship following outplanting, concurrently optimizing cumulative reef survivorship.

Self-generated morphology in lagoon reefs

PubMed Central

Hamblin, Michael G.

2015-01-01

The three-dimensional form of a coral reef develops through interactions and feedbacks between its constituent organisms and their environment. Reef morphology therefore contains a potential wealth of ecological information, accessible if the relationships between morphology and ecology can be decoded. Traditionally, reef morphology has been attributed to external controls such as substrate topography or hydrodynamic influences. Little is known about inherent reef morphology in the absence of external control. Here we use reef growth simulations, based on observations in the cellular reefs of Western Australia’s Houtman Abrolhos Islands, to show that reef morphology is fundamentally determined by the mechanical behaviour of the reef-building organisms themselves—specifically their tendency to either remain in place or to collapse. Reef-building organisms that tend to remain in place, such as massive and encrusting corals or coralline algae, produce nodular reefs, whereas those that tend to collapse, such as branching Acropora, produce cellular reefs. The purest reef growth forms arise in sheltered lagoons dominated by a single type of reef builder, as in the branching Acropora-dominated lagoons of the Abrolhos. In these situations reef morphology can be considered a phenotype of the predominant reef building organism. The capacity to infer coral type from reef morphology can potentially be used to identify and map specific coral habitat in remotely sensed images. More generally, identifying ecological mechanisms underlying other examples of self-generated reef morphology can potentially improve our understanding of present-day reef ecology, because any ecological process capable of shaping a reef will almost invariably be an important process in real time on the living reef. PMID:26175962

Branched tellurium hollow nanofibers by galvanic displacement reaction and their sensing performance toward nitrogen dioxide.

PubMed

Park, Hosik; Jung, Hyunsung; Zhang, Miluo; Chang, Chong Hyun; Ndifor-Angwafor, N George; Choa, Yongho; Myung, Nosang V

2013-04-07

Electrospinning and galvanic displacement reaction were combined to synthesize ultra-long hollow tellurium (Te) nanofibers with controlled dimensions, morphology and crystallinity by simply tailoring the electrolyte concentration applied. Within different morphologies of nanofibers, the branched Te nanostructure shows the greatest sensing performance towards NO2 at room temperature.

Sensory Neuron Fates Are Distinguished by a Transcriptional Switch that Regulates Dendrite Branch Stabilization

PubMed Central

Smith, Cody J.; O’Brien, Timothy; Chatzigeorgiou, Marios; Spencer, W. Clay; Feingold-Link, Elana; Husson, Steven J.; Hori, Sayaka; Mitani, Shohei; Gottschalk, Alexander; Schafer, William R.; Miller, David M.

2013-01-01

SUMMARY Sensory neurons adopt distinct morphologies and functional modalities to mediate responses to specific stimuli. Transcription factors and their downstream effectors orchestrate this outcome but are incompletely defined. Here, we show that different classes of mechanosensory neurons in C. elegans are distinguished by the combined action of the transcription factors MEC-3, AHR-1, and ZAG-1. Low levels of MEC-3 specify the elaborate branching pattern of PVD nociceptors, whereas high MEC-3 is correlated with the simple morphology of AVM and PVM touch neurons. AHR-1 specifies AVM touch neuron fate by elevating MEC-3 while simultaneously blocking expression of nociceptive genes such as the MEC-3 target, the claudin-like membrane protein HPO-30, that promotes the complex dendritic branching pattern of PVD. ZAG-1 exercises a parallel role to prevent PVM from adopting the PVD fate. The conserved dendritic branching function of the Drosophila AHR-1 homolog, Spineless, argues for similar pathways in mammals. PMID:23889932

Anatomy of the lamprey ear: morphological evidence for occurrence of horizontal semicircular ducts in the labyrinth of Petromyzon marinus

USGS Publications Warehouse

Maklad, Adel; Reed, Caitlyn; Johnson, Nicholas S.; Fritzsch, Bernd

2014-01-01

In jawed (gnathostome) vertebrates, the inner ears have three semicircular canals arranged orthogonally in the three Cartesian planes: one horizontal (lateral) and two vertical canals. They function as detectors for angular acceleration in their respective planes. Living jawless craniates, cyclostomes (hagfish and lamprey) and their fossil records seemingly lack a lateral horizontal canal. The jawless vertebrate hagfish inner ear is described as a torus or doughnut, having one vertical canal, and the jawless vertebrate lamprey having two. These observations on the anatomy of the cyclostome (jawless vertebrate) inner ear have been unchallenged for over a century, and the question of how these jawless vertebrates perceive angular acceleration in the yaw (horizontal) planes has remained open. To provide an answer to this open question we reevaluated the anatomy of the inner ear in the lamprey, using stereoscopic dissection and scanning electron microscopy. The present study reveals a novel observation: the lamprey has two horizontal semicircular ducts in each labyrinth. Furthermore, the horizontal ducts in the lamprey, in contrast to those of jawed vertebrates, are located on the medial surface in the labyrinth rather than on the lateral surface. Our data on the lamprey horizontal duct suggest that the appearance of the horizontal canal characteristic of gnathostomes (lateral) and lampreys (medial) are mutually exclusive and indicate a parallel evolution of both systems, one in cyclostomes and one in gnathostome ancestors.

Branching instability in expanding bacterial colonies.

PubMed

Giverso, Chiara; Verani, Marco; Ciarletta, Pasquale

2015-03-06

Self-organization in developing living organisms relies on the capability of cells to duplicate and perform a collective motion inside the surrounding environment. Chemical and mechanical interactions coordinate such a cooperative behaviour, driving the dynamical evolution of the macroscopic system. In this work, we perform an analytical and computational analysis to study pattern formation during the spreading of an initially circular bacterial colony on a Petri dish. The continuous mathematical model addresses the growth and the chemotactic migration of the living monolayer, together with the diffusion and consumption of nutrients in the agar. The governing equations contain four dimensionless parameters, accounting for the interplay among the chemotactic response, the bacteria-substrate interaction and the experimental geometry. The spreading colony is found to be always linearly unstable to perturbations of the interface, whereas branching instability arises in finite-element numerical simulations. The typical length scales of such fingers, which align in the radial direction and later undergo further branching, are controlled by the size parameters of the problem, whereas the emergence of branching is favoured if the diffusion is dominant on the chemotaxis. The model is able to predict the experimental morphologies, confirming that compact (resp. branched) patterns arise for fast (resp. slow) expanding colonies. Such results, while providing new insights into pattern selection in bacterial colonies, may finally have important applications for designing controlled patterns. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Rational growth of branched nanowire heterostructures with synthetically encoded properties and function

PubMed Central

Jiang, Xiaocheng; Tian, Bozhi; Xiang, Jie; Qian, Fang; Zheng, Gengfeng; Wang, Hongtao; Mai, Liqiang; Lieber, Charles M.

2011-01-01

Branched nanostructures represent unique, 3D building blocks for the “bottom-up” paradigm of nanoscale science and technology. Here, we report a rational, multistep approach toward the general synthesis of 3D branched nanowire (NW) heterostructures. Single-crystalline semiconductor, including groups IV, III–V, and II–VI, and metal branches have been selectively grown on core or core/shell NW backbones, with the composition, morphology, and doping of core (core/shell) NWs and branch NWs well controlled during synthesis. Measurements made on the different composition branched NW structures demonstrate encoding of functional p-type/n-type diodes and light-emitting diodes (LEDs) as well as field effect transistors with device function localized at the branch/backbone NW junctions. In addition, multibranch/backbone NW structures were synthesized and used to demonstrate capability to create addressable nanoscale LED arrays, logic circuits, and biological sensors. Our work demonstrates a previously undescribed level of structural and functional complexity in NW materials, and more generally, highlights the potential of bottom-up synthesis to yield increasingly complex functional systems in the future. PMID:21730174

Branch classification: A new mechanism for improving branch predictor performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, P.Y.; Hao, E.; Patt, Y.

There is wide agreement that one of the most significant impediments to the performance of current and future pipelined superscalar processors is the presence of conditional branches in the instruction stream. Speculative execution is one solution to the branch problem, but speculative work is discarded if a branch is mispredicted. For it to be effective, speculative work is discarded if a branch is mispredicted. For it to be effective, speculative execution requires a very accurate branch predictor; 95% accuracy is not good enough. This paper proposes branch classification, a methodology for building more accurate branch predictors. Branch classification allows anmore » individual branch instruction to be associated with the branch predictor best suited to predict its direction. Using this approach, a hybrid branch predictor can be constructed such that each component branch predictor predicts those branches for which it is best suited. To demonstrate the usefulness of branch classification, an example classification scheme is given and a new hybrid predictor is built based on this scheme which achieves a higher prediction accuracy than any branch predictor previously reported in the literature.« less

FoxO regulates microtubule dynamics and polarity to promote dendrite branching in Drosophila sensory neurons

PubMed Central

Sears, James C.; Broihier, Heather T.

2016-01-01

The size and shape of dendrite arbors are defining features of neurons and critical determinants of neuronal function. The molecular mechanisms establishing arborization patterns during development are not well understood, though properly regulated microtubule (MT) dynamics and polarity are essential. We previously found that FoxO regulates axonal MTs, raising the question of whether it also regulates dendritic MTs and morphology. Here we demonstrate that FoxO promotes dendrite branching in all classes of Drosophila dendritic arborization (da) neurons. FoxO is required both for initiating growth of new branches and for maintaining existing branches. To elucidate FoxO function, we characterized MT organization in both foxO null and overexpressing neurons. We find that FoxO directs MT organization and dynamics in dendrites. Moreover, it is both necessary and sufficient for anterograde MT polymerization, which is known to promote dendrite branching. Lastly, FoxO promotes proper larval nociception, indicating a functional consequence of impaired da neuron morphology in foxO mutants. Together, our results indicate that FoxO regulates dendrite structure and function and suggest that FoxO-mediated pathways control MT dynamics and polarity. PMID:27546375

Application of morphologic burrow interpretations to discern continental burrow architects: Lungfish or crayfish?

USGS Publications Warehouse

Hasiotis, Stephen T.; Mitchell, Charles E.; Dubiel, Russell R.

1993-01-01

A methodology for trace fossil identification using burrowing signatures is tested by evaluating ancient and modern lungfish and crayfish burrows and comparing them to previously undescribed burrows in a stratigraphic interval thought to contain both lungfish and crayfish burrows. Permian burrows that bear skeletal remains of the lungfish Gnathorhiza, from museum collections, were evaluated to identify unique burrow morphologies that could be used to distinguish lungfish from crayfish burrows when fossil remains are absent. The lungfish burrows were evaluated for details of the burrowing mechanism preserved in the burrow morphologies together forming burrowing signatures and were compared to new burrows in the Chinle Formation of western Colorado to test the methodology of using burrow signatures to identify unknown burrows.Permian lungfish aestivation burrows show simple, nearly vertical, unbranched architectures and relatively smooth surficial morphologies with characteristic quasi‐horizontal striae on the burrow walls and vertical striae on the bulbous terminus. Burrow lengths do not exceed 0.5 m. In contrast, modern and ancient crayfish burrows exhibit simple to highly complex architectures with highly textured surficial morphologies. Burrow lengths may reach 4 to 5 m.Burrow morphologies unlike those identified in Gnathorhiza aestivation burrows were found in four burrow groups from museum collections. Two of these groups exhibit simple architectures and horizontal striae that were greater in sinuosity and magnitude, respectively. One of these burrows contains the remains of Lysoro‐phus, but the burrow surface reveals no reliable surficial characteristics. It is not clear whether Lysorophustruly burrowed or merely occupied a pre‐existing structure. The other two groups exhibit surficial morphologies similar to those found on modern and ancient crayfish burrows and may provide evidence of freshwater crayfish in the Permian.Burrows from the Upper

Two Algorithms for High-throughput and Multi-parametric Quantification of Drosophila Neuromuscular Junction Morphology.

PubMed

Castells-Nobau, Anna; Nijhof, Bonnie; Eidhof, Ilse; Wolf, Louis; Scheffer-de Gooyert, Jolanda M; Monedero, Ignacio; Torroja, Laura; van der Laak, Jeroen A W M; Schenck, Annette

2017-05-03

Synaptic morphology is tightly related to synaptic efficacy, and in many cases morphological synapse defects ultimately lead to synaptic malfunction. The Drosophila larval neuromuscular junction (NMJ), a well-established model for glutamatergic synapses, has been extensively studied for decades. Identification of mutations causing NMJ morphological defects revealed a repertoire of genes that regulate synapse development and function. Many of these were identified in large-scale studies that focused on qualitative approaches to detect morphological abnormalities of the Drosophila NMJ. A drawback of qualitative analyses is that many subtle players contributing to NMJ morphology likely remain unnoticed. Whereas quantitative analyses are required to detect the subtler morphological differences, such analyses are not yet commonly performed because they are laborious. This protocol describes in detail two image analysis algorithms "Drosophila NMJ Morphometrics" and "Drosophila NMJ Bouton Morphometrics", available as Fiji-compatible macros, for quantitative, accurate and objective morphometric analysis of the Drosophila NMJ. This methodology is developed to analyze NMJ terminals immunolabeled with the commonly used markers Dlg-1 and Brp. Additionally, its wider application to other markers such as Hrp, Csp and Syt is presented in this protocol. The macros are able to assess nine morphological NMJ features: NMJ area, NMJ perimeter, number of boutons, NMJ length, NMJ longest branch length, number of islands, number of branches, number of branching points and number of active zones in the NMJ terminal.

On the missing second generation AGB stars in NGC 6752

NASA Astrophysics Data System (ADS)

Cassisi, Santi; Salaris, Maurizio; Pietrinferni, Adriano; Vink, Jorick S.; Monelli, Matteo

2014-11-01

In recent years the view of Galactic globular clusters as simple stellar populations has changed dramatically, it is now thought that basically all globular clusters host multiple stellar populations, each with its own chemical abundance pattern and colour-magnitude diagram sequence. Recent spectroscopic observations of asymptotic giant branch stars in the globular cluster NGC 6752 have disclosed a low [Na/Fe] abundance for the whole sample, suggesting that they are all first generation stars, and that all second generation stars fail to reach the AGB in this cluster. A scenario proposed to explain these observations invokes strong mass loss in second generation horizontal branch stars - all located at the hot side of the blue and extended horizontal branch of this cluster - possibly induced by the metal enhancement associated to radiative levitation. This enhanced mass loss would prevent second generation stars from reaching the asymptotic giant branch phase, thus explaining at the same time the low value of the ratio between horizontal branch and asymptotic giant branch stars (the R2 parameter) observed in NGC 6752. We have critically discussed this mass-loss scenario, finding that the required mass-loss rates are of the order of 10-9 M⊙ yr-1, significantly higher than current theoretical and empirical constraints. By making use of synthetic horizontal branch simulations, we demonstrate that our modelling correctly predicts the R2 parameter for NGC 6752, without the need to invoke very efficient mass loss during the core He-burning stage. As a test of our stellar models we show that we can reproduce the observed value of R2 for both M 3, a cluster of approximately the same metallicity and with a redder horizontal branch morphology, and M 13, a cluster with a horizontal branch very similar to NGC 6752. However, our simulations for the NGC 6752 horizontal branch predict however the presence of a significant fraction of second generation stars (about 50%) along

Functional morphology and comparative anatomy of appendicular musculature in Cuban Anolis lizards with different locomotor habits.

PubMed

Anzai, Wataru; Omura, Ayano; Diaz, Antonio Cadiz; Kawata, Masakado; Endo, Hideki

2014-07-01

We examined the diversity of the musculoskeletal morphology in the limbs of Anolis lizards with different habitats and identified variations in functional and morphological adaptations to different ecologies or behaviors. Dissection and isolation of 40 muscles from the fore- and hindlimbs of five species of Anolis were performed, and the muscle mass and length of the moment arm were compared after body size effects were removed. Ecologically and behaviorally characteristic morphological differences were observed in several muscles. Well-developed hindlimb extensors were observed in ground-dwelling species, A. sagrei and A. bremeri, and were considered advantageous for running, whereas adept climber species possessed expanded femoral retractors for weight-bearing during climbing. Moreover, morphological variations were observed among arboreal species. Wider excursions of the forelimb joint characterized A. porcatus, presumably enabling branch-to-branch locomotion, while A. equestris and A. angusticeps possessed highly developed adductor muscles for grasping thick branches or twigs. These findings suggest divergent evolution of musculoskeletal characteristic in the limbs within the genus Anolis, with correlations observed among morphological traits, locomotor performance, and habitat uses.

Morphologic features of basal cell carcinoma using the en-face mode in frequency domain optical coherence tomography.

PubMed

von Braunmühl, T; Hartmann, D; Tietze, J K; Cekovic, D; Kunte, C; Ruzicka, T; Berking, C; Sattler, E C

2016-11-01

Optical coherence tomography (OCT) has become a valuable non-invasive tool in the in vivo diagnosis of non-melanoma skin cancer, especially of basal cell carcinoma (BCC). Due to an updated software-supported algorithm, a new en-face mode - similar to the horizontal en-face mode in high-definition OCT and reflectance confocal microscopy - surface-parallel imaging is possible which, in combination with the established slice mode of frequency domain (FD-)OCT, may offer additional information in the diagnosis of BCC. To define characteristic morphologic features of BCC using the new en-face mode in addition to the conventional cross-sectional imaging mode for three-dimensional imaging of BCC in FD-OCT. A total of 33 BCC were examined preoperatively by imaging in en-face mode as well as cross-sectional mode in FD-OCT. Characteristic features were evaluated and correlated with histopathology findings. Features established in the cross-sectional imaging mode as well as additional features were present in the en-face mode of FD-OCT: lobulated structures (100%), dark peritumoral rim (75%), bright peritumoral stroma (96%), branching vessels (90%), compressed fibrous bundles between lobulated nests ('star shaped') (78%), and intranodular small bright dots (51%). These features were also evaluated according to the histopathological subtype. In the en-face mode, the lobulated structures with compressed fibrous bundles of the BCC were more distinct than in the slice mode. FD-OCT with a new depiction for horizontal and vertical imaging modes offers additional information in the diagnosis of BCC, especially in nodular BCC, and enhances the possibility of the evaluation of morphologic tumour features. © 2016 European Academy of Dermatology and Venereology.

hamlet, a binary genetic switch between single- and multiple- dendrite neuron morphology.

PubMed

Moore, Adrian W; Jan, Lily Yeh; Jan, Yuh Nung

2002-08-23

The dendritic morphology of neurons determines the number and type of inputs they receive. In the Drosophila peripheral nervous system (PNS), the external sensory (ES) neurons have a single nonbranched dendrite, whereas the lineally related multidendritic (MD) neurons have extensively branched dendritic arbors. We report that hamlet is a binary genetic switch between these contrasting morphological types. In hamlet mutants, ES neurons are converted to an MD fate, whereas ectopic hamlet expression in MD precursors results in transformation of MD neurons into ES neurons. Moreover, hamlet expression induced in MD neurons undergoing dendrite outgrowth drastically reduces arbor branching.

Morphological Examination and Phylogenetic Analyses of Phycopeltis spp. (Trentepohliales, Ulvophyceae) from Tropical China

PubMed Central

Zhu, Huan; Zhao, Zhijuan; Xia, Shuang; Hu, Zhengyu; Liu, Guoxiang

2015-01-01

During an investigation of Trentepohliales (Ulvophyceae) from tropical areas in China, four species of the genus Phycopeltis were identified: Phycopeltis aurea, P. epiphyton, P. flabellata and P. prostrata. The morphological characteristics of both young and adult thalli were observed and compared. Three species (P. flabellata, P. aurea and P. epiphyton) shared a symmetrical development with dichotomously branching vegetative cells during early stages; conversely, P. prostrata had dishevelled filaments with no dichotomously branching filaments and no symmetrical development. The adult thalli of the former three species shared common morphological characteristics, such as equally dichotomous filaments, absence of erect hair and gametangia formed in prostate vegetative filaments. Phylogenetic analyses based on SSU and ITS rDNA sequences showed that the three morphologically similar species were in a clade that was sister to a clade containing T. umbrina and T. abietina, thus confirming morphological monophyly. Conversely, Phycopeltis prostrata, a species with erect filaments, sessile gametangia on the basal erect hair, larger length/width ratio of vegetative cells and very loosely coalescent prostrate filaments, branched separately from the core Phycopeltis group and the T. umbrina and T. abietina clade. Based on morphological and molecular evidence, the genus Phycopeltis was paraphyletic. Furthermore, the traditional taxonomic criteria for Phycopeltis must be reassessed based on phylogeny using more species. A new circumscription of the Phycopeltis and the erection of new genera are recommended. PMID:25643363

Dimensions of subcortical infarcts associated with first- to third-order branches of the basal ganglia arteries.

PubMed

Phan, Thanh G; van der Voort, Sanne; Beare, Richard; Ma, Henry; Clissold, Benjamin; Holt, Michael; Ly, John; Foster, Emma; Thong, Eleanor; Stuckey, Stephen; Cassell, Martin D; Srikanth, Velandai

2013-01-01

It has been described that lacunar infarct is characterized by its smallish size (15-20 mm) in the axial plane. However, the size of the basal ganglia artery responsible for this type of infarct is uncertain. Detection of small arterial occlusion is not possible with current angiography, hindering correlation of arterial occlusion with subcortical infarct size. Recently, investigators have published microangiographic templates of arteries supplying the basal ganglia. These templates display first-order (proximal) to third-order (distal) branching of these arteries and can help with estimating the likely site of arterial disease in subcortical infarcts. We correlated the dimensions of subcortical infarcts with the order of arterial branching described in a microangiographic template. Such data may provide further clues about the type of arteries associated with subcortical infarcts and assist in refining the concept of lacunar infarction. Patients with subcortical infarcts on MR imaging (MRI) admitted to our institution between 2009 and 2011 were included in the study. Infarcts were manually segmented and registered to a standard brain template. These segmented infarcts were scaled and overlapped with published microangiographic templates, and used by 6 raters who independently estimated the branching order of arterial disease that might result in these infarcts. We used regression analysis to relate these ratings to infarct dimensions. Among 777 patients, there were 33 (58% male) patients with subcortical infarcts. The mean age was 63.1 ± 15.1 years. Infarct dimensions for the groups were as follows: group 1 (first-order branch): height 37.6 ± 7.4 mm, horizontal width 21.2 ± 11.6 mm, anterior-posterior length 36.8 ± 20.1 mm; group 2 (second-order branch): height 25.2 ± 7.9 mm, horizontal width 16.6 ± 22.8 mm, anterior-posterior length 16.1 ± 8.0 mm; group 3 (third-order branch): height 11.6 ± 5.7 mm, axial width 5.3 ± 3.1 mm, anterior-posterior length 5

Intramuscular communicating branches in the flexor digitorum profundus: dissection and Sihler's staining.

PubMed

Won, Sung-Yoon; Choi, Da-Yae; Lee, Jae-Gi; Yoon, Kwan-Hyun; Kwak, Hyun-Ho; Hu, Kyung-Seok; Kim, Hee-Jin

2010-03-01

This study was designed to clarify the anatomy of the intramuscular communicating branch (ICb) between the median and ulnar nerves in the flexor digitorum profundus (FDP), and morphologically demonstrate the location of connection. Twenty Korean cadavers were dissected and a further 8 were subjected to modified Sihler's staining to investigate the pattern of innervation of the ICb and the location of its communicating points in muscle. The median and ulnar nerves divided into small branches before entering FDP muscle. Of these small branches, one or two met inside the muscle. This communicating pattern could be classified into three types: type I, communicating branches in both the proximal and distal regions; type II, at least one communicating branch in the proximal region; type III, at least one communicating branch in the distal region. Of 20 dissected specimens, no case of type I was observed, but 3 cases of type II and 15 cases of type III were found. No ICbs at all were found in two of the dissected specimens. In eight stained specimens, one was classified as type I, two as type II, and five as type III. The proximal communicating branches were located at 34.1% from the interepicondylar line, inside the third muscle bundle. The distal communicating branches were located at 66.0% from the interepicondylar line, between third and fourth muscle bundles. These findings could provide critical anatomical information regarding the nerve distribution of FDP focused on the ICbs.

Existing branches correlatively inhibit further branching in Trifolium repens: possible mechanisms

PubMed Central

Thomas, R. G.; Hay, M. J. M.

2011-01-01

In Trifolium repens removal of any number of existing branches distal to a nodal root stimulates development of axillary buds further along the stem such that the complement of branches distal to a nodal root remains constant. This study aimed to assess possible mechanisms by which existing branches correlatively inhibit the outgrowth of axillary buds distal to them. Treatments were applied to basal branches to evaluate the roles of three postulated inhibitory mechanisms: (I) the transport of a phloem-mobile inhibitory feedback signal from branches into the main stem; (II) the polar flow of auxin from branches into the main stem acting to limit further branch development; or (III) the basal branches functioning as sinks for a net root-derived stimulatory signal (NRS). Results showed that transport of auxin, or of a non-auxin phloem-mobile signal, from basal branches did not influence regulation of correlative inhibition and were consistent with the possibility that the intra-plant distribution of NRS could be involved in the correlative inhibition of distal buds by basal branches. This study supports existing evidence that regulation of branching in T. repens is dominated by a root-derived stimulatory signal, initially distributed via the xylem, the characterization of which will progress the generic understanding of branching regulation. PMID:21071681

A new morphology algorithm for shoreline extraction from DEM data

NASA Astrophysics Data System (ADS)

Yousef, Amr H.; Iftekharuddin, Khan; Karim, Mohammad

2013-03-01

Digital elevation models (DEMs) are a digital representation of elevations at regularly spaced points. They provide an accurate tool to extract the shoreline profiles. One of the emerging sources of creating them is light detection and ranging (LiDAR) that can capture a highly dense cloud points with high resolution that can reach 15 cm and 100 cm in the vertical and horizontal directions respectively in short periods of time. In this paper we present a multi-step morphological algorithm to extract shorelines locations from the DEM data and a predefined tidal datum. Unlike similar approaches, it utilizes Lowess nonparametric regression to estimate the missing values within the DEM file. Also, it will detect and eliminate the outliers and errors that result from waves, ships, etc by means of anomality test with neighborhood constrains. Because, there might be some significant broken regions such as branches and islands, it utilizes a constrained morphological open and close to reduce these artifacts that can affect the extracted shorelines. In addition, it eliminates docks, bridges and fishing piers along the extracted shorelines by means of Hough transform. Based on a specific tidal datum, the algorithm will segment the DEM data into water and land objects. Without sacrificing the accuracy and the spatial details of the extracted boundaries, the algorithm should smooth and extract the shoreline profiles by tracing the boundary pixels between the land and the water segments. For given tidal values, we qualitatively assess the visual quality of the extracted shorelines by superimposing them on the available aerial photographs.

Neocortical neuronal morphology in the Siberian Tiger (Panthera tigris altaica) and the clouded leopard (Neofelis nebulosa).

PubMed

Johnson, Cameron B; Schall, Matthew; Tennison, Mackenzie E; Garcia, Madeleine E; Shea-Shumsky, Noah B; Raghanti, Mary Ann; Lewandowski, Albert H; Bertelsen, Mads F; Waller, Leona C; Walsh, Timothy; Roberts, John F; Hof, Patrick R; Sherwood, Chet C; Manger, Paul R; Jacobs, Bob

2016-12-01

Despite extensive investigations of the neocortex in the domestic cat, little is known about neuronal morphology in larger felids. To this end, the present study characterized and quantified the somatodendritic morphology of neocortical neurons in prefrontal, motor, and visual cortices of the Siberian tiger (Panthera tigris altaica) and clouded leopard (Neofelis nebulosa). After neurons were stained with a modified Golgi technique (N = 194), dendritic branching and spine distributions were analyzed using computer-assisted morphometry. Qualitatively, aspiny and spiny neurons in both species appeared morphologically similar to those observed in the domestic cat. Although the morphology of spiny neurons was diverse, with the presence of extraverted, inverted, horizontal, and multiapical pyramidal neurons, the most common variant was the typical pyramidal neuron. Gigantopyramidal neurons in the motor cortex were extremely large, confirming the observation of Brodmann ([1909] Vergleichende Lokalisationlehre der Grosshirnrinde in ihren Prinzipien dargestellt auf Grund des Zellenbaues. Leipzig, Germany: J.A. Barth), who found large somata for these neurons in carnivores in general, and felids in particular. Quantitatively, a MARSplines analysis of dendritic measures differentiated typical pyramidal neurons between the Siberian tiger and the clouded leopard with 93% accuracy. In general, the dendrites of typical pyramidal neurons were more complex in the tiger than in the leopards. Moreover, dendritic measures in tiger pyramidal neurons were disproportionally large relative to body/brain size insofar as they were nearly as extensive as those observed in much larger mammals (e.g., African elephant). Comparison of neuronal morphology in a more diverse collection of larger felids may elucidate the comparative context for the relatively large size of the pyramidal neurons observed in the present study. J. Comp. Neurol. 524:3641-3665, 2016. © 2016 Wiley Periodicals, Inc. �

When Can Clades Be Potentially Resolved with Morphology?

PubMed Central

Bapst, David W.

2013-01-01

Morphology-based phylogenetic analyses are the only option for reconstructing relationships among extinct lineages, but often find support for conflicting hypotheses of relationships. The resulting lack of phylogenetic resolution is generally explained in terms of data quality and methodological issues, such as character selection. A previous suggestion is that sampling ancestral morphotaxa or sampling multiple taxa descended from a long-lived, unchanging lineage can also yield clades which have no opportunity to share synapomorphies. This lack of character information leads to a lack of ‘intrinsic’ resolution, an issue that cannot be solved with additional morphological data. It is unclear how often we should expect clades to be intrinsically resolvable in realistic circumstances, as intrinsic resolution must increase as taxonomic sampling decreases. Using branching simulations, I quantify intrinsic resolution across several models of morphological differentiation and taxonomic sampling. Intrinsically unresolvable clades are found to be relatively frequent in simulations of both extinct and living taxa under realistic sampling scenarios, implying that intrinsic resolution is an issue for morphology-based analyses of phylogeny. Simulations which vary the rates of sampling and differentiation were tested for their agreement to observed distributions of durations from well-sampled fossil records and also having high intrinsic resolution. This combination only occurs in those datasets when differentiation and sampling rates are both unrealistically high relative to branching and extinction rates. Thus, the poor phylogenetic resolution occasionally observed in morphological phylogenetics may result from a lack of intrinsic resolvability within groups. PMID:23638034

GLABROUS INFLORESCENCE STEMS (GIS) is required for trichome branching through gibberellic acid signaling in Arabidopsis.

PubMed

An, Lijun; Zhou, Zhongjing; Su, Sha; Yan, An; Gan, Yinbo

2012-02-01

Cell differentiation generally corresponds to the cell cycle, typically forming a non-dividing cell with a unique differentiated morphology, and Arabidopsis trichome is an excellent model system to study all aspects of cell differentiation. Although gibberellic acid is reported to be involved in trichome branching in Arabidopsis, the mechanism for such signaling is unclear. Here, we demonstrated that GLABROUS INFLORESCENCE STEMS (GIS) is required for the control of trichome branching through gibberellic acid signaling. The phenotypes of a loss-of-function gis mutant and an overexpressor showed that GIS acted as a repressor to control trichome branching. Our results also show that GIS is not required for cell endoreduplication, and our molecular and genetic study results have shown that GIS functions downstream of the key regulator of trichome branching, STICHEL (STI), to control trichome branching through the endoreduplication-independent pathway. Furthermore, our results also suggest that GIS controls trichome branching in Arabidopsis through two different pathways and acts either upstream or downstream of the negative regulator of gibbellic acid signaling SPINDLY (SPY).

Evidences of early aqueous Mars: Implications on the origin of branched valleys in the Ius Chasma, Mars

NASA Astrophysics Data System (ADS)

Martha, Tapas R.; Jain, Nirmala; Vamshi, Gasiganti T.; Vinod Kumar, K.

2017-11-01

This study shows results of morphological and spectroscopic analyses of Ius Chasma and its southern branched valleys using Orbiter datasets such as Mars Reconnaissance Orbiter (MRO)-Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), High Resolution Imaging Science Experiment (MRO-HiRISE) and digital terrain model (HRSC-DTM). Result of the spectral analysis reveals presence of hydrated minerals such as opal, nontronite and vermiculite in the floor and wall rock areas Ius Chasma indicating alteration of parent rock in an water rich environment of early Mars. Topographic gradient and morphological evidences such as V-shaped valleys with theatre shaped stubby channels, dendritic drainage and river piracy indicate that these valleys were initially developed by surface runoff due to episodic floods and further expanded due to groundwater sapping controlled by faults and fractures. Minerals formed by aqueous alteration during valley formation and their intricate association with different morphological domains suggest that surface runoff played a key role in the development of branched valleys south of Ius Chasma on Mars.

Directional reflectance and milli-scale feather morphology of the African Emerald Cuckoo, Chrysococcyx cupreus.

PubMed

Harvey, Todd Alan; Bostwick, Kimberly S; Marschner, Steve

2013-09-06

Diverse plumages have evolved among birds through complex morphological modifications. We investigate how the interplay of light with surface and subsurface feather morphology determines the direction of light propagation, an understudied aspect of avian visual signalling. We hypothesize that milli-scale modifications of feathers produce anisotropic reflectance, the direction of which may be predicted by the orientation of the milli-scale structure. The subject of this study is the African Emerald Cuckoo, Chrysococcyx cupreus, noted for its shimmering green iridescent appearance. Using a spherical gantry, we measured the change in the directional reflectance across the feather surface and over a hemisphere of incident lighting directions. Using a microCT scanner, we also studied the morphology of the structural branches of the barb. We tracked the changes in the directional reflectance to the orientation of the structural branches as observed in the CT data. We conclude that (i) the far-field signal of the feather consists of multiple specular components, each associated with a different structural branch and (ii) the direction of each specular component is correlated to the orientation of the corresponding structure.

Horizontal Cross Bracing Detail, Vertical Cross Bracing Detail, Horizontal Cross ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Horizontal Cross Bracing Detail, Vertical Cross Bracing Detail, Horizontal Cross Bracing Detail, Vertical Cross Bracing-End Detail - Cumberland Covered Bridge, Spanning Mississinewa River, Matthews, Grant County, IN

DIVERGENT HORIZONTAL SUB-SURFACE FLOWS WITHIN ACTIVE REGION 11158

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jain, Kiran; Tripathy, S. C.; Hill, F., E-mail: kjain@nso.edu, E-mail: stripathy@nso.edu, E-mail: fhill@nso.edu

We measure the horizontal subsurface flow in a fast emerging active region (AR; NOAA 11158) using the ring-diagram technique and the Helioseismic and Magnetic Imager high spatial resolution Dopplergrams. This AR had a complex magnetic structure and displayed significant changes in morphology during its disk passage. Over a period of six days from 2011 February 11 to 16, the temporal variation in the magnitude of the total velocity is found to follow the trend of magnetic field strength. We further analyze regions of individual magnetic polarity within AR 11158 and find that the horizontal velocity components in these sub-regions havemore » significant variation with time and depth. The leading and trailing polarity regions move faster than the mixed-polarity region. Furthermore, both zonal and meridional components have opposite signs for trailing and leading polarity regions at all depths showing divergent flows within the AR. We also find a sharp decrease in the magnitude of total horizontal velocity in deeper layers around major flares. It is suggested that the re-organization of magnetic fields during flares, combined with the sunspot rotation, decreases the magnitude of horizontal flows or that the flow kinetic energy has been converted into the energy released by flares. After the decline in flare activity and sunspot rotation, the flows tend to follow the pattern of magnetic activity. We also observe less variation in the velocity components near the surface but these tend to increase with depth, further demonstrating that the deeper layers are more affected by the topology of ARs.« less

Towards engineered branch placement: Unreal™ match between vapour-liquid-solid glancing angle deposition nanowire growth and simulation

NASA Astrophysics Data System (ADS)

Taschuk, M. T.; Tucker, R. T.; LaForge, J. M.; Beaudry, A. L.; Kupsta, M. R.; Brett, M. J.

2013-12-01

The vapour-liquid-solid glancing angle deposition (VLS-GLAD) process is capable of producing complex nanotree structures with control over azimuthal branch orientation and height. We have developed a thin film growth simulation including ballistic deposition, simplified surface diffusion, and droplet-mediated cubic crystal growth for the VLS-GLAD process using the UnrealTM Development Kit. The use of a commercial game engine has provided an interactive environment while allowing a custom physics implementation. Our simulation's output is verified against experimental data, including a volumetric film reconstruction produced using focused ion beam and scanning-electron microscopy (SEM), crystallographic texture, and morphological characteristics such as branch orientation. We achieve excellent morphological and texture agreement with experimental data, as well as qualitative agreement with SEM imagery. The simplified physics in our model reproduces the experimental films, indicating that the dominant role flux geometry plays in the VLS-GLAD competitive growth process responsible for azimuthally oriented branches and biaxial crystal texture evolution. The simulation's successful reproduction of experimental data indicates that it should have predictive power in designing novel VLS-GLAD structures.

Effect aquadest-extracted Gloriosa superba seed as mutagen on morphology of Artemisia annua

NASA Astrophysics Data System (ADS)

Rahmawati, S. I.; Susilowati, A.; Yunus, A.; Widyastuti, Y.

2018-03-01

Gloriosa superba is a plant that contains colchicine in all parts of organs, especially in the seeds. Its extract is as a mutagen to produce plants with polyploid cells. Artemisia annua is a plant that produces active ingredients artemisinin as malarial drugs, hemorrhoids therapy, aromatherapy, antiviral, anticancer, and anti-bacterial. The aims of this research was to determine the effect aquadest-extracted Gloriosa superba seed as a mutagen to Artemisia annua morphology. Extraction of Gloriosa superba seeds obtained from Sukoharjo using maceration method with aquadest solvent (1: 1). The extracts were diluted (0, 25, 50, 75 and 100%) for Artemisia annua sprinkling with different times (0, 30, 60 and 90 minutes). Observations of morphology Artemisia annua included height, stem circumference, number of branches, number of leaves, leaf width and leaf length. The treatments did not affect plant morphology observation included height, stem circumference, number of branches, number of leaves, leaf width, and leaf length. The EB treatment (100%, 30 minutes) was higher (120 cm) than other. In all treatments stem circumference about 2.5 cm, number of branches ranged between 40-50, leaves width ranged 9-16c m, and leaf length ranged 8-15 cm.

Branching Search

NASA Astrophysics Data System (ADS)

Eliazar, Iddo

2017-12-01

Search processes play key roles in various scientific fields. A widespread and effective search-process scheme, which we term Restart Search, is based on the following restart algorithm: i) set a timer and initiate a search task; ii) if the task was completed before the timer expired, then stop; iii) if the timer expired before the task was completed, then go back to the first step and restart the search process anew. In this paper a branching feature is added to the restart algorithm: at every transition from the algorithm's third step to its first step branching takes place, thus multiplying the search effort. This branching feature yields a search-process scheme which we term Branching Search. The running time of Branching Search is analyzed, closed-form results are established, and these results are compared to the coresponding running-time results of Restart Search.

Microbiota Influences Morphology and Reproduction of the Brown Alga Ectocarpus sp.

PubMed Central

Tapia, Javier E.; González, Bernardo; Goulitquer, Sophie; Potin, Philippe; Correa, Juan A.

2016-01-01

Associated microbiota play crucial roles in health and disease of higher organisms. For macroalgae, some associated bacteria exert beneficial effects on nutrition, morphogenesis and growth. However, current knowledge on macroalgae–microbiota interactions is mostly based on studies on green and red seaweeds. In this study, we report that when cultured under axenic conditions, the filamentous brown algal model Ectocarpus sp. loses its branched morphology and grows with a small ball-like appearance. Nine strains of periphytic bacteria isolated from Ectocarpus sp. unialgal cultures were identified by 16S rRNA sequencing, and assessed for their effect on morphology, reproduction and the metabolites secreted by axenic Ectocarpus sp. Six of these isolates restored morphology and reproduction features of axenic Ectocarpus sp. Bacteria-algae co-culture supernatants, but not the supernatant of the corresponding bacterium growing alone, also recovered morphology and reproduction of the alga. Furthermore, colonization of axenic Ectocarpus sp. with a single bacterial isolate impacted significantly the metabolites released by the alga. These results show that the branched typical morphology and the individuals produced by Ectocarpus sp. are strongly dependent on the presence of bacteria, while the bacterial effect on the algal exometabolome profile reflects the impact of bacteria on the whole physiology of this alga. PMID:26941722

Microbiota Influences Morphology and Reproduction of the Brown Alga Ectocarpus sp.

PubMed

Tapia, Javier E; González, Bernardo; Goulitquer, Sophie; Potin, Philippe; Correa, Juan A

2016-01-01

Associated microbiota play crucial roles in health and disease of higher organisms. For macroalgae, some associated bacteria exert beneficial effects on nutrition, morphogenesis and growth. However, current knowledge on macroalgae-microbiota interactions is mostly based on studies on green and red seaweeds. In this study, we report that when cultured under axenic conditions, the filamentous brown algal model Ectocarpus sp. loses its branched morphology and grows with a small ball-like appearance. Nine strains of periphytic bacteria isolated from Ectocarpus sp. unialgal cultures were identified by 16S rRNA sequencing, and assessed for their effect on morphology, reproduction and the metabolites secreted by axenic Ectocarpus sp. Six of these isolates restored morphology and reproduction features of axenic Ectocarpus sp. Bacteria-algae co-culture supernatants, but not the supernatant of the corresponding bacterium growing alone, also recovered morphology and reproduction of the alga. Furthermore, colonization of axenic Ectocarpus sp. with a single bacterial isolate impacted significantly the metabolites released by the alga. These results show that the branched typical morphology and the individuals produced by Ectocarpus sp. are strongly dependent on the presence of bacteria, while the bacterial effect on the algal exometabolome profile reflects the impact of bacteria on the whole physiology of this alga.

Horizontal Cross Bracing Detail, Vertical Cross Bracing Detail, Horizontal Cross ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Horizontal Cross Bracing Detail, Vertical Cross Bracing Detail, Horizontal Cross Bracing Joint, Vertical Cross Bracing End Detail - Ceylon Covered Bridge, Limberlost Park, spanning Wabash River at County Road 900 South, Geneva, Adams County, IN

Anatomic suitability of aortoiliac aneurysms for next generation branched systems.

PubMed

Pearce, Benjamin J; Varu, Vinit N; Glocker, Roan; Novak, Zdenek; Jordan, William D; Lee, Jason T

2015-01-01

Preservation of internal iliac flow is an important consideration to prevent ischemic complications during endovascular aneurysm repair. We sought to determine the suitability of aortoiliac aneurysms for off-the-shelf iliac branched systems currently in clinical trial. Patients undergoing abdominal aortic aneurysm repair from 2004 to 2013 at 2 institutions were reviewed. Centerline diameters and lengths of aortoiliac morphology were measured using three-dimensional workstations and compared with inclusion/exclusion criteria for both Cook and Gore iliac branch devices. Of the nearly 2,400 aneurysm repairs performed during the study period, 99 patients had common iliac aneurysms suitable for imaging review. Eighteen of the 99 (18.2%) patients and 25/99 (25.3%) patients fit the inclusion criteria and would have been able to be treated using the Cook and Gore iliac branch devices, respectively. The most common reason for exclusion from Cook was internal iliac diameter of <6 or >9 mm (68/99, 68.7%). The most common reason for exclusion from Gore was proximal common iliac diameter of <17 mm (39/99, 39.4%) and inadequate internal iliac artery diameter of <6.5 or >13.5 mm (37/99, 37.3%). Comparing the included patients across both devices, a total of 35/99 (35.4%) of patients would be eligible for the treatment of aortoiliac aneurysms based on anatomic criteria. Only 35% of the aneurysm repairs involving common iliac arteries would have been candidates for the 2 iliac branch devices currently in trial based on anatomic criteria. The major common reason for exclusion is the internal iliac landing zone for both devices. Design modifications for future generation iliac branch technology should focus on diameter accommodations for the hypogastric branch stent and proximal and distal sizes of the iliac branch components. Familiarity with alternate branch preserving techniques is still needed in the majority of cases. Copyright © 2015 Elsevier Inc. All rights reserved.

The antagonistic modulation of Arp2/3 activity by N-WASP, WAVE2 and PICK1 defines dynamic changes in astrocyte morphology.

PubMed

Murk, Kai; Blanco Suarez, Elena M; Cockbill, Louisa M R; Banks, Paul; Hanley, Jonathan G

2013-09-01

Astrocytes exhibit a complex, branched morphology, allowing them to functionally interact with numerous blood vessels, neighboring glial processes and neuronal elements, including synapses. They also respond to central nervous system (CNS) injury by a process known as astrogliosis, which involves morphological changes, including cell body hypertrophy and thickening of major processes. Following severe injury, astrocytes exhibit drastically reduced morphological complexity and collectively form a glial scar. The mechanistic details behind these morphological changes are unknown. Here, we investigate the regulation of the actin-nucleating Arp2/3 complex in controlling dynamic changes in astrocyte morphology. In contrast to other cell types, Arp2/3 inhibition drives the rapid expansion of astrocyte cell bodies and major processes. This intervention results in a reduced morphological complexity of astrocytes in both dissociated culture and in brain slices. We show that this expansion requires functional myosin II downstream of ROCK and RhoA. Knockdown of the Arp2/3 subunit Arp3 or the Arp2/3 activator N-WASP by siRNA also results in cell body expansion and reduced morphological complexity, whereas depleting WAVE2 specifically reduces the branching complexity of astrocyte processes. By contrast, knockdown of the Arp2/3 inhibitor PICK1 increases astrocyte branching complexity. Furthermore, astrocyte expansion induced by ischemic conditions is delayed by PICK1 knockdown or N-WASP overexpression. Our findings identify a new morphological outcome for Arp2/3 activation in restricting rather than promoting outwards movement of the plasma membrane in astrocytes. The Arp2/3 regulators PICK1, and N-WASP and WAVE2 function antagonistically to control the complexity of astrocyte branched morphology, and this mechanism underlies the morphological changes seen in astrocytes during their response to pathological insult.

The antagonistic modulation of Arp2/3 activity by N-WASP, WAVE2 and PICK1 defines dynamic changes in astrocyte morphology

PubMed Central

Murk, Kai; Blanco Suarez, Elena M.; Cockbill, Louisa M. R.; Banks, Paul; Hanley, Jonathan G.

2013-01-01

Summary Astrocytes exhibit a complex, branched morphology, allowing them to functionally interact with numerous blood vessels, neighboring glial processes and neuronal elements, including synapses. They also respond to central nervous system (CNS) injury by a process known as astrogliosis, which involves morphological changes, including cell body hypertrophy and thickening of major processes. Following severe injury, astrocytes exhibit drastically reduced morphological complexity and collectively form a glial scar. The mechanistic details behind these morphological changes are unknown. Here, we investigate the regulation of the actin-nucleating Arp2/3 complex in controlling dynamic changes in astrocyte morphology. In contrast to other cell types, Arp2/3 inhibition drives the rapid expansion of astrocyte cell bodies and major processes. This intervention results in a reduced morphological complexity of astrocytes in both dissociated culture and in brain slices. We show that this expansion requires functional myosin II downstream of ROCK and RhoA. Knockdown of the Arp2/3 subunit Arp3 or the Arp2/3 activator N-WASP by siRNA also results in cell body expansion and reduced morphological complexity, whereas depleting WAVE2 specifically reduces the branching complexity of astrocyte processes. By contrast, knockdown of the Arp2/3 inhibitor PICK1 increases astrocyte branching complexity. Furthermore, astrocyte expansion induced by ischemic conditions is delayed by PICK1 knockdown or N-WASP overexpression. Our findings identify a new morphological outcome for Arp2/3 activation in restricting rather than promoting outwards movement of the plasma membrane in astrocytes. The Arp2/3 regulators PICK1, and N-WASP and WAVE2 function antagonistically to control the complexity of astrocyte branched morphology, and this mechanism underlies the morphological changes seen in astrocytes during their response to pathological insult. PMID:23843614

Branches of the Facial Artery.

PubMed

Hwang, Kun; Lee, Geun In; Park, Hye Jin

2015-06-01

The aim of this study is to review the name of the branches, to review the classification of the branching pattern, and to clarify a presence percentage of each branch of the facial artery, systematically. In a PubMed search, the search terms "facial," AND "artery," AND "classification OR variant OR pattern" were used. The IBM SPSS Statistics 20 system was used for statistical analysis. Among the 500 titles, 18 articles were selected and reviewed systematically. Most of the articles focused on "classification" according to the "terminal branch." Several authors classified the facial artery according to their terminal branches. Most of them, however, did not describe the definition of "terminal branch." There were confusions within the classifications. When the inferior labial artery was absent, 3 different types were used. The "alar branch" or "nasal branch" was used instead of the "lateral nasal branch." The angular branch was used to refer to several different branches. The presence as a percentage of each branch according to the branches in Gray's Anatomy (premasseteric, inferior labial, superior labial, lateral nasal, and angular) varied. No branch was used with 100% consistency. The superior labial branch was most frequently cited (95.7%, 382 arteries in 399 hemifaces). The angular branch (53.9%, 219 arteries in 406 hemifaces) and the premasseteric branch were least frequently cited (53.8%, 43 arteries in 80 hemifaces). There were significant differences among each of the 5 branches (P < 0.05) except between the angular branch and the premasseteric branch and between the superior labial branch and the inferior labial branch. The authors believe identifying the presence percentage of each branch will be helpful for surgical procedures.

Northern Hemisphere Nitrous Oxide Morphology during the 1989 AASE and the 1991-1992 AASE 2 Campaigns

NASA Technical Reports Server (NTRS)

Podolske, James R.; Loewenstein, Max; Weaver, Alex; Strahan, Susan; Chan, K. Roland

1993-01-01

Nitrous oxide vertical profiles and latitudinal distributions for the 1989 AASE and 1992 AASE II northern polar winters are developed from the ATLAS N2O dataset, using both potential temperature and pressure as vertical coordinates. Morphologies show strong descent occurring poleward of the polar jet. The AASE II morphology shows a mid latitude 'surf zone,' characterized by strong horizontal mixing, and a horizontal gradient south of 30 deg N due to the sub-tropical jet. These features are similar to those produced by two-dimensional photochemical models which include coupling between transport, radiation, and chemistry.

Northern hemisphere nitrous oxide morphology during the 1989 AASE and the 1991-1992 AASE 2 campaigns

NASA Technical Reports Server (NTRS)

Podolske, James R.; Loewenstein, Max; Weaver, Alex; Strahan, Susan E.; Chan, K. Roland

1993-01-01

Nitrous oxide vertical profiles and latitudinal distributions for the 1989 Airborne Antarctic Ozone Experiment (AASE) and 1992 AASE 2 northern polar winters are developed from the ATLAS N2O dataset, using both potential temperature and pressure as vertical coordinates. Morphologies show strong descent occuring poleward of the polar jet. The AASE 2 morphology shows a mid latitude 'surf zone', characterized by strong horizontal mixing, and a horizontal gradient south of 30 deg N due to the sub-tropical jet. These features are similar to those produced by two-dimensional photochemical models which include coupling between transport, radiation, and chemistry.

Directional reflectance and milli-scale feather morphology of the African Emerald Cuckoo, Chrysococcyx cupreus

PubMed Central

Harvey, Todd Alan; Bostwick, Kimberly S.; Marschner, Steve

2013-01-01

Diverse plumages have evolved among birds through complex morphological modifications. We investigate how the interplay of light with surface and subsurface feather morphology determines the direction of light propagation, an understudied aspect of avian visual signalling. We hypothesize that milli-scale modifications of feathers produce anisotropic reflectance, the direction of which may be predicted by the orientation of the milli-scale structure. The subject of this study is the African Emerald Cuckoo, Chrysococcyx cupreus, noted for its shimmering green iridescent appearance. Using a spherical gantry, we measured the change in the directional reflectance across the feather surface and over a hemisphere of incident lighting directions. Using a microCT scanner, we also studied the morphology of the structural branches of the barb. We tracked the changes in the directional reflectance to the orientation of the structural branches as observed in the CT data. We conclude that (i) the far-field signal of the feather consists of multiple specular components, each associated with a different structural branch and (ii) the direction of each specular component is correlated to the orientation of the corresponding structure. PMID:23825113

Sprouty / FGF signaling regulates the proximal-distal feather morphology and the size of dermal papillae

PubMed Central

Yue, Zhicao; Jiang, Ting Xin; Wu, Ping; Widelitz, Randall B; Chuong, Cheng Ming

2013-01-01

In a feather, there are distinct morphologies along the proximal-distal axis. The proximal part is a cylindrical stalk (calamus), whereas the distal part has barb and barbule branches. Here we focus on what molecular signaling activity can modulate feather stem cells to generate these distinct morphologies. We demonstrate the drastic tissue remodeling during feather cycling which includes initiation, growth and resting phases. In the growth phase, epithelial components undergo progressive changes from the collar growth zone to the ramogenic zone, to maturing barb branches along the proximal- distal axis. Mesenchymal components also undergo progressive changes from the dermal papilla, to the collar mesenchyme, to the pulp along the proximal- distal axis. Over-expression of Spry4, a negative regulator of receptor tyrosine kinases, promotes barb branch formation at the expense of the epidermal collar. It even induces barb branches from the follicle sheath (equivalent to the outer root sheath in hair follicles). The results are feathers with expanded feather vane regions and small or missing proximal feather shafts (the calamus). Spry4 also expands the pulp region while reducing the size of dermal papillae, leading to a failure to regenerate. In contrast, over-expressing Fgf10 increases the size of the dermal papillae, expands collar epithelia and mesenchyme, but also prevents feather branch formation and feather keratin differentiation. These results suggest that coordinated Sprouty/FGF pathway activity at different stages is important to modulate feather epidermal stem cells to form distinct feather morphologies along the proximal-distal feather axis. PMID:23000358

Effects of nanoparticle shape on the morphology and properties of porous CdSe assemblies (aerogels).

PubMed

Yu, Hongtao; Brock, Stephanie L

2008-08-01

We demonstrate the effect of differently shaped CdSe nanoscale building blocks (dots, rods, branched nanoparticles, and hyperbranched nanoparticles) on the morphologies, surface characteristics, and optical properties of resultant porous CdSe nanostructured aerogels. Monolithic CdSe aerogels were produced by controlled oxidative removal of surface thiolate ligands from differently shaped CdSe nanoparticles to yield a wet gel, followed by CO(2) supercritical drying. The X-ray diffraction data show that the resultant CdSe aerogels maintain the crystalline phase of the building blocks without significant grain growth. However, the transmission electron microscopy images indicate that the morphology of CdSe aerogels changes from a colloid-type morphology to a polymer-type morphology when the building block changes from dot to rod or the branched nanoparticle. The morphology of the CdSe aerogel assembled from hyperbranched nanoparticles appears to be intermediate between the colloid-type and the polymer-type. Nitrogen physisorption measurements suggest that the surface areas and porosity are a direct function of the shape of the primary building blocks, with aerogels formed from rods or branched particles exhibiting the greatest surface areas (>200 m(2)/g) and those prepared from hyperbranched nanoparticles exhibiting the least (<100 m(2)/g). Band gap measurements and photoluminescence studies show that the as-prepared CdSe aerogels retain to a large extent the intrinsic quantum confinement of the differently shaped building blocks, despite being connected into a 3D network.

Phylogenetics of Anthyllis (Leguminosae: Papilionoideae: Loteae): Partial incongruence between nuclear and plastid markers, a long branch problem and implications for morphological evolution.

PubMed

Degtjareva, Galina V; Valiejo-Roman, Carmen M; Samigullin, Tahir H; Guara-Requena, Miguel; Sokoloff, Dmitry D

2012-02-01

Phylogenetic relationships in the genus Anthyllis (Leguminosae: Papilionoideae: Loteae) were investigated using data from the nuclear ribosomal internal transcribed spacer regions (ITS) and three plastid regions (psbA-trnH intergenic spacer, petB-petD region and rps16 intron). Bayesian and maximum parsimony (MP) analysis of a concatenated plastid dataset recovered well-resolved trees that are topologically similar, with many clades supported by unique indels. MP and Bayesian analyses of the ITS sequence data recovered trees that have several well-supported topological differences, both among analyses, and to trees inferred from the plastid data. The most substantial of these concerns A. vulneraria and A. lemanniana, whose placement in the parsimony analysis of the ITS data appears to be due to a strong long-branch effect. Analysis of the secondary structure of the ITS1 spacer showed a strong bias towards transitions in A. vulneraria and A. lemanniana, many of which were also characteristic of certain outgroup taxa. This may contribute to the conflicting placement of this clade in the MP tree for the ITS data. Additional conflicts between the plastid and ITS trees were more taxonomically focused. These differences may reflect the occurrence of reticulate evolution between closely related species, including a possible hybrid origin for A. hystrix. The patterns of incongruence between the plastid and the ITS data seem to correlate with taxon ranks. All of our phylogenetic analyses supported the monophyly of Anthyllis (incl. Hymenocarpos). Although they are often taxonomically associated with Anthyllis, the genera Dorycnopsis and Tripodion are shown here to be more closely related to other genera of Loteae. We infer up to six major clades in Anthyllis that are morphologically well-characterized, and which could be recognized as sections. Four of these agree with various morphology-based classifications, while the other two are novel. We reconstruct the evolution of

Morphology and isozyme band-profile as sexual determinant of nutmeg plant (Myristica fragrants Houttj).

NASA Astrophysics Data System (ADS)

Karmanah; Maslahat, M.; Nurhayati, dan L.

2016-01-01

Sex information in nutmeg plant is important to distinguish between male and female species. The recommendation of optimum sex-ratio for a nutmeg plantation is 1:10. This research is aimed to discover the morphological characteristic of nutmeg plant and the difference of leaf pattern as sexual determinant between male and female plant with the comparison of isozyme analysis. The result of morphological identification provided from 3 research farm location indicated that female nutmeg was higher, with longer and wider leaf, more vein, bigger diameter of stem and branching angle as compared to male nutmeg. Two parameters which were widht of leaf and branching angle showed significant differences, where female nutmeg plants have wider leaves and branching angle. Isozyme analysis suggested that the analysis of peroxidase enzyme (PER) was better and able to provide more information than aspartarte amino transferase (AAT) and acid phospatase (ACP) Enzymes.

Short branches lead to systematic artifacts when BLAST searches are used as surrogate for phylogenetic reconstruction.

PubMed

Dick, Amanda A; Harlow, Timothy J; Gogarten, J Peter

2017-02-01

Long Branch Attraction (LBA) is a well-known artifact in phylogenetic reconstruction when dealing with branch length heterogeneity. Here we show another phenomenon, Short Branch Attraction (SBA), which occurs when BLAST searches, a phenetic analysis, are used as a surrogate method for phylogenetic analysis. This error also results from branch length heterogeneity, but this time it is the short branches that are attracting. The SBA artifact is reciprocal and can be returned 100% of the time when multiple branches differ in length by a factor of more than two. SBA is an intended feature of BLAST searches, but becomes an issue, when top scoring BLAST hit analyses are used to infer Horizontal Gene Transfers (HGTs), assign taxonomic category with environmental sequence data in phylotyping, or gather homologous sequences for building gene families. SBA can lead researchers to believe that there has been a HGT event when only vertical descent has occurred, cause slowly evolving taxa to be over-represented and quickly evolving taxa to be under-represented in phylotyping, or systematically exclude quickly evolving taxa from analyses. SBA also contributes to the changing results of top scoring BLAST hit analyses as the database grows, because more slowly evolving taxa, or short branches, are added over time, introducing more potential for SBA. SBA can be detected by examining reciprocal best BLAST hits among a larger group of taxa, including the known closest phylogenetic neighbors. Therefore, one should look for this phenomenon when conducting best BLAST hit analyses as a surrogate method to identify HGTs, in phylotyping, or when using BLAST to gather homologous sequences. Copyright © 2016 Elsevier Inc. All rights reserved.

Growth of modern branched columnar stromatolites in Lake Joyce, Antarctica.

PubMed

Mackey, T J; Sumner, D Y; Hawes, I; Jungblut, A D; Andersen, D T

2015-07-01

Modern decimeter-scale columnar stromatolites from Lake Joyce, Antarctica, show a change in branching pattern during a period of lake level rise. Branching patterns correspond to a change in cyanobacterial community composition as preserved in authigenic calcite crystals. The transition in stromatolite morphology is preserved by mineralized layers that contain microfossils and cylindrical molds of cyanobacterial filaments. The molds are composed of two populations with different diameters. Large diameter molds (>2.8 μm) are abundant in calcite forming the oldest stromatolite layers, but are absent from younger layers. In contrast, <2.3 μm diameter molds are common in all stromatolites layers. Loss of large diameter molds corresponds to the transition from smooth-sided stromatolitic columns to branched and irregular columns. Mold diameters are similar to trichome diameters of the four most abundant living cyanobacteria morphotypes in Lake Joyce: Phormidium autumnale morphotypes have trichome diameters >3.5 μm, whereas Leptolyngbya antarctica, L. fragilis, and Pseudanabaena frigida morphotypes have diameters <2.3 μm. P. autumnale morphotypes were only common in mats at <12 m depth. Mats containing abundant P. autumnale morphotypes were smooth, whereas mats with few P. autumnale morphotypes contained small peaks and protruding bundles of filaments, suggesting that the absence of P. autumnale morphotypes allowed small-scale topography to develop on mats. Comparisons of living filaments and mold diameters suggest that P. autumnale morphotypes were present early in stromatolite growth, but disappeared from the community through time. We hypothesize that the mat-smoothing behavior of P. autumnale morphotypes inhibited nucleation of stromatolite branches. When P. autumnale morphotypes were excluded from the community, potentially reflecting a rise in lake level, short-wavelength roughness provided nuclei for stromatolite branches. This growth history provides a

Do Branch Lengths Help to Locate a Tree in a Phylogenetic Network?

PubMed

Gambette, Philippe; van Iersel, Leo; Kelk, Steven; Pardi, Fabio; Scornavacca, Celine

2016-09-01

Phylogenetic networks are increasingly used in evolutionary biology to represent the history of species that have undergone reticulate events such as horizontal gene transfer, hybrid speciation and recombination. One of the most fundamental questions that arise in this context is whether the evolution of a gene with one copy in all species can be explained by a given network. In mathematical terms, this is often translated in the following way: is a given phylogenetic tree contained in a given phylogenetic network? Recently this tree containment problem has been widely investigated from a computational perspective, but most studies have only focused on the topology of the phylogenies, ignoring a piece of information that, in the case of phylogenetic trees, is routinely inferred by evolutionary analyses: branch lengths. These measure the amount of change (e.g., nucleotide substitutions) that has occurred along each branch of the phylogeny. Here, we study a number of versions of the tree containment problem that explicitly account for branch lengths. We show that, although length information has the potential to locate more precisely a tree within a network, the problem is computationally hard in its most general form. On a positive note, for a number of special cases of biological relevance, we provide algorithms that solve this problem efficiently. This includes the case of networks of limited complexity, for which it is possible to recover, among the trees contained by the network with the same topology as the input tree, the closest one in terms of branch lengths.

Networks of highly branched stigmarian rootlets developed on the first giant trees

PubMed Central

Hetherington, Alexander J.; Berry, Christopher M.; Dolan, Liam

2016-01-01

Lycophyte trees, up to 50 m in height, were the tallest in the Carboniferous coal swamp forests. The similarity in their shoot and root morphology led to the hypothesis that their rooting (stigmarian) systems were modified leafy shoot systems, distinct from the roots of all other plants. Each consists of a branching main axis covered on all sides by lateral structures in a phyllotactic arrangement; unbranched microphylls developed from shoot axes, and largely unbranched stigmarian rootlets developed from rhizomorphs axes. Here, we reexamined the morphology of extinct stigmarian systems preserved as compression fossils and in coal balls from the Carboniferous period. Contrary to the long-standing view of stigmarian systems, where shoot-like rhizomorph axes developed largely unbranched, root-hairless rootlets, here we report that stigmarian rootlets were highly branched, developed at a density of ∼25,600 terminal rootlets per meter of rhizomorph, and were covered in root hairs. Furthermore, we show that this architecture is conserved among their only extant relatives, herbaceous plants in the Isoetes genus. Therefore, despite the difference in stature and the time that has elapsed, we conclude that both extant and extinct rhizomorphic lycopsids have the same rootlet system architecture. PMID:27226309

Pipeline corridors through wetlands - impacts on plant communities: Deep Creek and Brandy Branch crossings, Nassau County, Florida

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shem, L.M.; Van Dyke, G.D.; Zimmerman, R.E.

The goal of the Gas Research Institute Wetland Corridors Program is to document impacts of existing pipelines on the wetlands they traverse. To accomplish this goal, 12 existing wetland crossings were surveyed. These sites varied in elapsed time since pipeline construction, wetland type, pipeline installation techniques, and right-of-way (ROW) management practices. This report presents the results of surveys conducted July 14-18, 1992, at the Deep Creek and the Brandy Branch crossings of a pipeline installed during May 1991 in Nassau County, Florida. Both floodplains supported bottomland hardwood forests. The pipeline at the Deep Creek crossing was installed by means ofmore » horizontal directional drilling after the ROW had been clear-cut, while the pipeline at the Brandy Branch crossing was installed by means of conventional open trenching. Neither site was seeded or fertilized. At the time of sampling, a dense vegetative community, made up primarily of native perennial herbaceous species, occupied the ROW within the Deep Creek floodplain. The Brandy Branch ROW was vegetated by a less dense stand of primarily native perennial herbaceous plants. Plant diversity was also lower at the Brandy Branch crossing than at the Deep Creek crossing. The results suggest that some of the differences in plant communities are related to the more hydric conditions at the Brandy Branch floodplain.« less

BRANCHED FIBERS FROM OLD FAST-TWITCH DYSTROPHIC MUSCLES ARE THE SITES OF TERMINAL DAMAGE IN MUSCULAR DYSTROPHY.

PubMed

Kiriaev, Leonit; Kueh, Sindy; Morley, John W; North, Kathryn N; Houweling, Peter J; Head, Stewart I

2018-02-07

A striking pathological feature of dystrophinopathies is the presence of morphologically abnormal branched skeletal muscle fibers. The deterioration of muscle contractile function in Duchenne muscular dystrophy is accompanied by both an increase in number and complexity of these branched fibers. We propose that when number and complexity of branched fibers reaches a critical threshold, "tipping point" the branches in and of themselves are the site of contraction-induced rupture. In the present study, we use the dystrophic mdx mouse and littermate controls to study the pre-diseased dystrophic fast-twitch EDL muscle at 2-3-weeks, the peak myonecrotic phase at 6-9 weeks and finally "old" at 58-112 weeks. Using a combination of isolated muscle function contractile measurements coupled with single fiber imaging and confocal microscope imaging of cleared whole muscles we identified a distinct pathophysiology; acute fiber rupture at branch nodes, which occurs in "old" fast-twitch EDL muscle approaching the end stage of the dystrophinopathy muscle disease, where the EDL muscles are entirely composed of complexed branched fibers. This evidence supports our concept of "tipping point" where the number and extent of fiber branching reaches a level where the branching itself terminally compromises muscle function, irrespective of the absence of dystrophin.

The Multiple Stellar Populations in the Ancient LMC Globular Clusters Hodge 11 and NGC 2210

NASA Astrophysics Data System (ADS)

Chaboyer, Brian; Gilligan, Christina; Wagner-Kaiser, Rachel; Mackey, Dougal; Sarajedini, Ata; Cummings, Jeffrey; Grocholski, Aaron; Geisler, Doug; Cohen, Roger; Villanova, Sandro; Yang, Soung-Chul; Parisi, Celeste

2018-01-01

Hubble Space telescope images of the ancient LMC globular clusters Hodge 11 and NGC 2210 in the F336W, F606W and F814W filters were obtained between June 2016 and April 2017. These deep images has been analyzed with the Dolphot software package. High quality photometry has been obtained from three magnitudes brighter than the horizontal branch, to about four magnitudes fainter than the main sequence turn-off. Both clusters show an excess of red main sequence stars in the F336W filter, indicating that multiple stellar populations exist in both clusters. Hodge 11 shows irregularities in its horizontal branch morphology, which is indicative of the presence of an approximately 0.1 dex internal helium abundance spread.

Horizontal baffle for nuclear reactors

DOEpatents

Rylatt, John A.

1978-01-01

A horizontal baffle disposed in the annulus defined between the core barrel and the thermal liner of a nuclear reactor thereby physically separating the outlet region of the core from the annular area below the horizontal baffle. The horizontal baffle prevents hot coolant that has passed through the reactor core from thermally damaging apparatus located in the annulus below the horizontal baffle by utilizing the thermally induced bowing of the horizontal baffle to enhance sealing while accommodating lateral motion of the baffle base plate.

Comparison of morphological and genetic analyses reveals cryptic divergence and morphological plasticity in Stylophora (Cnidaria, Scleractinia)

NASA Astrophysics Data System (ADS)

Stefani, Fabrizio; Benzoni, F.; Yang, S.-Y.; Pichon, M.; Galli, P.; Chen, C. A.

2011-12-01

A combined morphological and genetic study of the coral genus Stylophora investigated species boundaries in the Gulf of Aden, Yemen. Two mitochondrial regions, including the hypervariable IGS9 spacer and the control region, and a fragment of rDNA were used for phylogenetic analysis. Results were compared by multivariate analysis on the basis of branch morphology and corallite morphometry. Two species were clearly discriminated by both approaches. The first species was characterised by small corallites and a low morphological variability and was ascribed to a new geographical record of Stylophora madagascarensis on the basis of its phylogenetic distinction and its morphological similarity to the type material. The second species was characterised by larger corallite size and greater morphological variability and was ascribed to Stylophora pistillata. The analysis was extended to the intrageneric level for other S. pistillata populations from the Red Sea and the Pacific Ocean. Strong internal divergence was evident in the genus Sty lophora. S. pistillata populations were split into two highly divergent Red Sea/Gulf of Aden and western Pacific lineages with significant morphological overlap, which suggests they represent two distinct cryptic species. The combined use of morphological and molecular approaches, so far proved to be a powerful tool for the re-delineation of species boundaries in corals, provided novel evidence of cryptic divergence in this group of marine metazoans.

Double-bromo and extraterminal (BET) domain proteins regulate dendrite morphology and mechanosensory function

PubMed Central

Bagley, Joshua A.; Yan, Zhiqiang; Zhang, Wei; Wildonger, Jill

2014-01-01

A complex array of genetic factors regulates neuronal dendrite morphology. Epigenetic regulation of gene expression represents a plausible mechanism to control pathways responsible for specific dendritic arbor shapes. By studying the Drosophila dendritic arborization (da) neurons, we discovered a role of the double-bromodomain and extraterminal (BET) family proteins in regulating dendrite arbor complexity. A loss-of-function mutation in the single Drosophila BET protein encoded by female sterile 1 homeotic [fs(1)h] causes loss of fine, terminal dendritic branches. Moreover, fs(1)h is necessary for the induction of branching caused by a previously identified transcription factor, Cut (Ct), which regulates subtype-specific dendrite morphology. Finally, disrupting fs(1)h function impairs the mechanosensory response of class III da sensory neurons without compromising the expression of the ion channel NompC, which mediates the mechanosensitive response. Thus, our results identify a novel role for BET family proteins in regulating dendrite morphology and a possible separation of developmental pathways specifying neural cell morphology and ion channel expression. Since the BET proteins are known to bind acetylated histone tails, these results also suggest a role of epigenetic histone modifications and the “histone code,” in regulating dendrite morphology. PMID:25184680

Double-bromo and extraterminal (BET) domain proteins regulate dendrite morphology and mechanosensory function.

PubMed

Bagley, Joshua A; Yan, Zhiqiang; Zhang, Wei; Wildonger, Jill; Jan, Lily Yeh; Jan, Yuh Nung

2014-09-01

A complex array of genetic factors regulates neuronal dendrite morphology. Epigenetic regulation of gene expression represents a plausible mechanism to control pathways responsible for specific dendritic arbor shapes. By studying the Drosophila dendritic arborization (da) neurons, we discovered a role of the double-bromodomain and extraterminal (BET) family proteins in regulating dendrite arbor complexity. A loss-of-function mutation in the single Drosophila BET protein encoded by female sterile 1 homeotic [fs(1)h] causes loss of fine, terminal dendritic branches. Moreover, fs(1)h is necessary for the induction of branching caused by a previously identified transcription factor, Cut (Ct), which regulates subtype-specific dendrite morphology. Finally, disrupting fs(1)h function impairs the mechanosensory response of class III da sensory neurons without compromising the expression of the ion channel NompC, which mediates the mechanosensitive response. Thus, our results identify a novel role for BET family proteins in regulating dendrite morphology and a possible separation of developmental pathways specifying neural cell morphology and ion channel expression. Since the BET proteins are known to bind acetylated histone tails, these results also suggest a role of epigenetic histone modifications and the "histone code," in regulating dendrite morphology. © 2014 Bagley et al.; Published by Cold Spring Harbor Laboratory Press.

Asymmetric Branching in Biological Resource Distribution Networks

NASA Astrophysics Data System (ADS)

Brummer, Alexander Byers

There is a remarkable relationship between an organism's metabolic rate (resting power consumption) and the organism's mass. It may be a universal law of nature that an organism's resting metabolic rate is proportional to its mass to the power of 3/4. This relationship, known as Kleiber's Law, appears to be valid for both plants and animals. This law is important because it implies that larger organisms are more efficient than smaller organisms, and knowledge regarding metabolic rates are essential to a multitude of other fields in ecology and biology. This includes modeling the interactions of many species across multiple trophic levels, distributions of species abundances across large spatial landscapes, and even medical diagnostics for respiratory and cardiovascular pathologies. Previous models of vascular networks that seek to identify the origin of metabolic scaling have all been based on the unrealistic assumption of perfectly symmetric branching. In this dissertation I will present a theory of asymmetric branching in self-similar vascular networks (published by Brummer et al. in [9]). The theory shows that there can exist a suite of vascular forms that result in the often observed 3/4 metabolic scaling exponent of Kleiber's Law. Furthermore, the theory makes predictions regarding major morphological features related to vascular branching patterns and their relationships to metabolic scaling. These predictions are suggestive of evolutionary convergence in vascular branching. To test these predictions, I will present an analysis of real mammalian and plant vascular data that shows: (i) broad patterns in vascular networks across entire animal kingdoms and (ii) within these patterns, plant and mammalian vascular networks can be uniquely distinguished from one another (publication in preparation by Brummer et al.). I will also present results from a computational study in support of point (i). Namely, that asymmetric branching may be the optimal strategy to

Effects of hemin, CO2, and pH on the branching of Candida albicans filamentous forms.

PubMed

Jakab, Ágnes; Antal, Károly; Emri, Tamás; Boczonádi, Imre; Imre, Alexandra; Gebri, Enikő; Majoros, László; Pfliegler, Walter Péter; Szarka, Máté; Balla, György; Balla, József; Pócsi, István

2016-12-01

Morphological transitions of wild-type and oxidative stress-tolerant Candida albicans strains were followed in the RPMI-FBS culture medium at pH values and CO 2 levels characteristic for the anatomical niches inhabited by this opportunistic human pathogen fungus, including the oral cavity as well as the intestinal and vaginal lumens. Selected cultures were also supplemented with hemin modeling bleedings. Germination as well as elongation and branching of hyphae were monitored in the cultures using time-lapse video microscopy. Unexpectedly, branching time, which is defined as the time taken until the first branch of hypha emerges for the first time after germination, correlated well with alterations in the environmental conditions meanwhile no such correlations were found for germination time (time lasted until the appearance of the germination tube). Based on these observations, hypotheses were set up to estimate the significance of branching time in the pathogenesis of both superficial and systemic candidiases.

Myosin-II controls cellular branching morphogenesis and migration in 3D by minimizing cell surface curvature

PubMed Central

Elliott, Hunter; Fischer, Robert A.; Myers, Kenneth A.; Desai, Ravi A.; Gao, Lin; Chen, Christopher S.; Adelstein, Robert; Waterman, Clare M.; Danuser, Gaudenz

2014-01-01

In many cases cell function is intimately linked to cell shape control. We utilized endothelial cell branching morphogenesis as a model to understand the role of myosin-II in shape control of invasive cells migrating in 3D collagen gels. We applied principles of differential geometry and mathematical morphology to 3D image sets to parameterize cell branch structure and local cell surface curvature. We find that Rho/ROCK-stimulated myosin-II contractility minimizes cell-scale branching by recognizing and minimizing local cell surface curvature. Utilizing micro-fabrication to constrain cell shape identifies a positive feedback mechanism in which low curvature stabilizes myosin-II cortical association, where it acts to maintain minimal curvature. The feedback between myosin-II regulation by and control of curvature drives cycles of localized cortical myosin-II assembly and disassembly. These cycles in turn mediate alternating phases of directionally biased branch initiation and retraction to guide 3D cell migration. PMID:25621949

Effects of branch height on leaf gas exchange, branch hydraulic conductance and branch sap flux in open-grown ponderosa pine.

PubMed

Hubbard, Robert M; Bond, Barbara J; Senock, Randy S; Ryan, Michael G

2002-06-01

Recent studies have shown that stomata respond to changes in hydraulic conductance of the flow path from soil to leaf. In open-grown tall trees, branches of different heights may have different hydraulic conductances because of differences in path length and growth. We determined if leaf gas exchange, branch sap flux, leaf specific hydraulic conductance, foliar carbon isotope composition (delta13C) and ratios of leaf area to sapwood area within branches were dependent on branch height (10 and 25 m) within the crowns of four open-grown ponderosa pine (Pinus ponderosa Laws.) trees. We found no difference in leaf gas exchange or leaf specific hydraulic conductance from soil to leaf between the upper and lower canopy of our study trees. Branch sap flux per unit leaf area and per unit sapwood area did not differ between the 10- and 25-m canopy positions; however, branch sap flux per unit sapwood area at the 25-m position had consistently lower values. Branches at the 25-m canopy position had lower leaf to sapwood area ratios (0.17 m2 cm-2) compared with branches at the 10-m position (0.27 m2 cm-2) (P = 0.03). Leaf specific conductance of branches in the upper crown did not differ from that in the lower crown. Other studies at our site indicate lower hydraulic conductance, sap flux, whole-tree canopy conductance and photosynthesis in old trees compared with young trees. This study suggests that height alone may not explain these differences.

Morphology of Arabidopsis Grown under Chronic Centrifugation and on the Clinostat 123

PubMed Central

Brown, Allan H.; Dahl, A. Orville; Chapman, David K.

1976-01-01

Morphological measurements were made on populations of Arabidopsis thaliana grown from seed for 21 days under essentially constant environmental conditions except for the influence of gravitational or centrifugal accelerations. Growth conditions were what had been proposed for experiments in an artificial satellite. Observations are reported for plants grown at normal 1-g upright or on horizontal clinostats and for plants grown on a centrifuge. Increased g-force, up to 15 times normal, was found to have significant but small effects on some morphological end points. The plants' sensitivity to the magnitude of the g-force was much less than to its vector direction. Data from centrifuge experiments (which determined the g-functions for particular characters) were extrapolated to zero-g to predict a set of morphological characteristics of a plant developing in the satellite environment. As an alternative means of predicting properties of a zero-g plant, characteristics of plants grown on horizontal clinostats were measured. The results of these two predictive methods were not in agreement. Clinostat grown plants were morphologically distinct from upright stationary controls. When plants were grown while rotating in the upright position on vertical clinostats they were similar to stationary plants also grown upright, but there were small differences some of which were statistically significant. PMID:16659483

Horizontal Collision Avoidance Systems Study

DOT National Transportation Integrated Search

1973-12-01

This report presents the results of an analytical study of the merits and mechanization requirements of horizontal collision avoidance systems (CAS). The horizontal and combined horizontal/vertical maneuvers which provide adequate miss distance with ...

Entanglement branching operator

NASA Astrophysics Data System (ADS)

Harada, Kenji

2018-01-01

We introduce an entanglement branching operator to split a composite entanglement flow in a tensor network which is a promising theoretical tool for many-body systems. We can optimize an entanglement branching operator by solving a minimization problem based on squeezing operators. The entanglement branching is a new useful operation to manipulate a tensor network. For example, finding a particular entanglement structure by an entanglement branching operator, we can improve a higher-order tensor renormalization group method to catch a proper renormalization flow in a tensor network space. This new method yields a new type of tensor network states. The second example is a many-body decomposition of a tensor by using an entanglement branching operator. We can use it for a perfect disentangling among tensors. Applying a many-body decomposition recursively, we conceptually derive projected entangled pair states from quantum states that satisfy the area law of entanglement entropy.

Micro-CT evaluation of apical delta morphologies in human teeth.

PubMed

Gao, Xianhua; Tay, Franklin R; Gutmann, James L; Fan, Wei; Xu, Ting; Fan, Bing

2016-11-07

The apical delta is an intricate system within the root canal and incompletely debridement may affect the long-term prognosis of root canal therapy. The aim of the present study is to investigate the morphologic features of apical deltas in human teeth with micro-computed tomography (micro-CT) using a centreline-fitting algorithm. One hundred and thirty-six apical deltas were detected in 1400 teeth. Molars had more apical deltas (15.8%) than anterior teeth (6.3%). In maxillary molars, the mesiobuccal root had a significantly higher prevalence of apical delta than the palatal root or the distobuccal root. The median vertical distance of the apical delta was 1.87 mm with 13% more than 3 mm. The median diameter and length of the apical delta branches were 132.3 and 934.5 μm. Apical delta branches were not straight with cross-sectional shapes being non-circular. These morphological features of apical delta may complicate debridement of the infected root canal system.

Plasticity first: molecular signatures of a complex morphological trait in filamentous cyanobacteria.

PubMed

Koch, Robin; Kupczok, Anne; Stucken, Karina; Ilhan, Judith; Hammerschmidt, Katrin; Dagan, Tal

2017-08-31

Filamentous cyanobacteria that differentiate multiple cell types are considered the peak of prokaryotic complexity and their evolution has been studied in the context of multicellularity origins. Species that form true-branching filaments exemplify the most complex cyanobacteria. However, the mechanisms underlying the true-branching morphology remain poorly understood despite of several investigations that focused on the identification of novel genes or pathways. An alternative route for the evolution of novel traits is based on existing phenotypic plasticity. According to that scenario - termed genetic assimilation - the fixation of a novel phenotype precedes the fixation of the genotype. Here we show that the evolution of transcriptional regulatory elements constitutes a major mechanism for the evolution of new traits. We found that supplementation with sucrose reconstitutes the ancestral branchless phenotype of two true-branching Fischerella species and compared the transcription start sites (TSSs) between the two phenotypic states. Our analysis uncovers several orthologous TSSs whose transcription level is correlated with the true-branching phenotype. These TSSs are found in genes that encode components of the septosome and elongasome (e.g., fraC and mreB). The concept of genetic assimilation supplies a tenable explanation for the evolution of novel traits but testing its feasibility is hindered by the inability to recreate and study the evolution of present-day traits. We present a novel approach to examine transcription data for the plasticity first route and provide evidence for its occurrence during the evolution of complex colony morphology in true-branching cyanobacteria. Our results reveal a route for evolution of the true-branching phenotype in cyanobacteria via modification of the transcription level of pre-existing genes. Our study supplies evidence for the 'plasticity-first' hypothesis and highlights the importance of transcriptional regulation in

Horizontal EDNA miner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Justice, J.C.; Delli-Gatti, F.A.

1985-12-03

A mining machine is utilized for making original generally horizontal bores in coal seams, and for enlarging preexisting bores. A single cutting head is mounted for rotation about a first horizontal axis generally perpendicular to the dimension of elongation of the horizontal bore, and is pivotal about a second horizontal axis, parallel to the first axis, to change its cutting, vertical position within the bore. A non-rotatable body member, with side wall supports, is mounted posteriorly of the cutting head, and includes a conveyor mechanism and a power mechanism operatively connected to it. The machine can be sumped into amore » bore and then the cutting head rotated about the second axis to change the vertical position thereof, and then moved rearwardly, any cut material being continuously conveyed to the bore mouth by the conveyor mechanism. The amount of vertical movement during the pivoting action about the second axis is controlled in response to the automatic sensing of the thickness of the coal seam in which the machine operates.« less

Anatomical risk evaluation of iatrogenic injury to the infrapatellar branch of the saphenous nerve during medial meniscus arthroscopic surgery.

PubMed

Koch, Guillaume; Kling, Agathe; Ramamurthy, Nitin; Edalat, Faramarz; Cazzato, Roberto Luigi; Kahn, Jean-Luc; Garnon, Julien; Clavert, Philippe

2017-06-01

To determine the relationship of the medial meniscus with the infrapatellar branches of the saphenous nerve, the primary goal is to define and characterize different risk areas for these nerves during medial meniscus surgery. After dissecting 20 embalmed cadaver knees, we defined 7 readily identifiable anatomical landmarks. For each knee, we recorded 2 morphological criteria and 16 measurements. The most common anatomical course is a main trunk that is 8 mm anterior to the tuberculum adductorium and 60 mm posterior to the midpoint of the medial patellar margin. It has two main infrapatellar branches. The nerve division is 23 mm above the joint line. The path is oblique with an angle of 55.5°. The anterior meniscal landmark is 24 mm from the upper branch and 42.5 mm from the lower branch. The posterior meniscal landmark is 55 mm from the upper branch and 38 mm from the lower branch. We defined a common anatomical course for the saphenous nerve and its infrapatellar branches. Then, three different areas were defined at risk for iatrogenic nerve injuries during medial meniscus.

Coherent array of branched filamentary scales along the wing margin of a small moth

NASA Astrophysics Data System (ADS)

Yoshida, Akihiro; Tejima, Shin; Sakuma, Masayuki; Sakamaki, Yositaka; Kodama, Ryuji

2017-04-01

In butterflies and moths, the wing margins are fringed with specialized scales that are typically longer than common scales. In the hindwings of some small moths, the posterior margins are fringed with particularly long filamentary scales. Despite the small size of these moth wings, these scales are much longer than those of large moths and butterflies. In the current study, photography of the tethered flight of a small moth, Phthorimaea operculella, revealed a wide array composed of a large number of long filamentary scales. This array did not become disheveled in flight, maintaining a coherent sheet-like structure during wingbeat. Examination of the morphology of individual scales revealed that each filamentary scale consists of a proximal stalk and distal branches. Moreover, not only long scales but also shorter scales of various lengths were found to coexist in each small section of the wing margin. Scale branches were ubiquitously and densely distributed within the scale array to form a mesh-like architecture similar to a nonwoven fabric. We propose that possible mechanical interactions among branched filamentary scales, mediated by these branches, may contribute to maintaining a coherent sheet-like structure of the scale array during wingbeat.

Comparative morphology of stingray lateral line canal and electrosensory systems.

PubMed

Jordan, Laura K

2008-11-01

Elasmobranchs (sharks, skates, and rays) possess a variety of sensory systems including the mechanosensory lateral line and electrosensory systems, which are particularly complex with high levels of interspecific variation in batoids (skates and rays). Rays have dorsoventrally compressed, laterally expanded bodies that prevent them from seeing their mouths and more often than not, their prey. This study uses quantitative image analysis techniques to identify, quantify, and compare structural differences that may have functional consequences in the detection capabilities of three Eastern Pacific stingray species. The benthic round stingray, Urobatis halleri, pelagic stingray, Pteroplatytrygon (Dasyatis) violacea, and benthopelagic bat ray, Myliobatis californica, show significant differences in sensory morphology. Ventral lateral line canals correlate with feeding ecology and differ primarily in the proportion of pored and nonpored canals and the degree of branching complexity. Urobatis halleri shows a high proportion of nonpored canals, while P. violacea has an intermediate proportion of pored and nonpored canals with almost no secondary branching of pored canals. In contrast, M. californica has extensive and highly branched pored ventral lateral line canals that extended laterally toward the wing tips on the anterior edge of the pectoral fins. Electrosensory morphology correlates with feeding habitat and prey mobility; benthic feeders U. halleri and M. californica, have greater electrosensory pore numbers and densities than P. violacea. The percentage of the wing surface covered by these sensory systems appears to be inversely related to swimming style. These methods can be applied to a broader range of species to enable further discussion of the relationship of phylogeny, ecology, and morphology, while the results provide testable predictions of detection capabilities.

Identifying heterogeneity in rates of morphological evolution: discrete character change in the evolution of lungfish (Sarcopterygii; Dipnoi).

PubMed

Lloyd, Graeme T; Wang, Steve C; Brusatte, Stephen L

2012-02-01

Quantifying rates of morphological evolution is important in many macroevolutionary studies, and critical when assessing possible adaptive radiations and episodes of punctuated equilibrium in the fossil record. However, studies of morphological rates of change have lagged behind those on taxonomic diversification, and most authors have focused on continuous characters and quantifying patterns of morphological rates over time. Here, we provide a phylogenetic approach, using discrete characters and three statistical tests to determine points on a cladogram (branches or entire clades) that are characterized by significantly high or low rates of change. These methods include a randomization approach that identifies branches with significantly high rates and likelihood ratio tests that pinpoint either branches or clades that have significantly higher or lower rates than the pooled rate of the remainder of the tree. As a test case for these methods, we analyze a discrete character dataset of lungfish, which have long been regarded as "living fossils" due to an apparent slowdown in rates since the Devonian. We find that morphological rates are highly heterogeneous across the phylogeny and recover a general pattern of decreasing rates along the phylogenetic backbone toward living taxa, from the Devonian until the present. Compared with previous work, we are able to report a more nuanced picture of lungfish evolution using these new methods. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

Electrophysiological evidence of doubly innervated branched muscle fibers in the human brachioradialis muscle.

PubMed

Lateva, Zoia C; McGill, Kevin C

2007-12-01

Motor-unit action potentials (MUAPs) with unstable satellite (late-latency) components are found in EMG signals from the brachioradialis muscles of normal subjects. We analyzed the morphology and blocking behavior of these MUAPs to determine their anatomical origin. EMG signals were recorded from the brachioradialis muscles of 5 normal subjects during moderate-level isometric contractions. MUAP waveforms, discharge patterns, and blocking were determined using computer-aided EMG decomposition. Twelve MUAPs with unstable satellite potentials were detected, always two together in the same signal. Each MUAP also had a second unstable component associated with its main spike. The blocking behavior of the unstable components depended on how close together the two MUAPs were when they discharged. The latencies and blocking behavior indicate that the unstable components came from branched muscle fibers innervated by two different motoneurons. The satellite potentials were due to action potentials that traveled to the branching point along one branch and back along the other. The blockings were due to action-potential collisions when both motoneurons discharged close together in time. Animal studies suggest that branched muscle fibers may be a normal characteristic of series-fibered muscles. This study adds to our understanding of these muscles in humans.

Role of TCP Gene BRANCHED1 in the Control of Shoot Branching in Arabidopsis.

PubMed

Poza-Carrión, César; Aguilar-Martínez, José Antonio; Cubas, Pilar

2007-11-01

Branching patterns are major determinants of plant architecture. They depend both on leaf phillotaxy (branch primordia are formed in the axils of leaves) and on the decision of buds to grow out to give a branch or to remain dormant. In Arabidopsis, several genes involved in the long-distance signalling of the control of branch outgrowth have been identified. However, the genes acting inside the buds to cause growth arrest remained unknown until now. In the February issue of Plant Cell we have described the function of BRANCHED1 (BRC1), an Arabidopsis gene coding for a plant-specific transcription factor of the TCP family that is expressed in the buds and prevents their development. Loss of BRC1 function leads to accelerated AM initiation, precocious progression of bud development and excess of shoot branching. BRC1 transcription is affected by endogenous and environmental signals controlling branching and we have shown that BRC1 function mediates the response to these stimuli. Therefore we have proposed that BRC1 function represents the point at which signals controlling branching are integrated within axillary buds.

Bundle Branch Block

MedlinePlus

... known cause. Causes can include: Left bundle branch block Heart attacks (myocardial infarction) Thickened, stiffened or weakened ... myocarditis) High blood pressure (hypertension) Right bundle branch block A heart abnormality that's present at birth (congenital) — ...

Origin of collapsed pits and branched valleys surrounding the Ius chasma on Mars

NASA Astrophysics Data System (ADS)

Vamshi, G. T.; Martha, T. R.; Vinod Kumar, K.

2014-11-01

Chasma is a deep, elongated and steep sided depression on planetary surfaces. Several hypothesis have been proposed regarding the origin of chasma. In this study, we analysed morphological features in north and south of Ius chasma. Collapsed pits and branched valleys alongwith craters are prominent morphological features surrounding Ius Chasma, which forms the western part of the well known Valles Marineris chasma system on Martian surface. Analysis of images from the High Resolution Stereo Camera (HRSC) in ESA's Mars Express (MEX) with a spatial resolution of 10 m shows linear arrangement of pits north of the Ius chasma. These pits were initially developed along existing narrow linear valleys parallel to Valles Merineris and are conical in shape unlike flat floored impact craters found adjacent to them. The width of conical pits ranges 1-10 km and depth ranges 1-2 km. With more subsidence, size of individual pits increased gradually and finally coalesced together to create a large depression forming a prominent linear valley. Arrangement of pits in this particular fashion can be attributed to collapse of the surface due to l arge hollows created in the subsurface because of the withdrawal of either magma or dry ice. Branched valleys which are prominent morphologic features south of the Ius chasma could have been formed due to groundwater sapping mechanism as proposed by previous researchers. Episodic release of groundwater in large quantity to the surface could have resulted in surface runoff creating V-shaped valleys, which were later modified into U-shaped valleys due to mass wasting and lack of continued surface runoff.

Epidemiological modeling in a branching population. Particular case of a general SIS model with two age classes.

PubMed

Jacob, C; Viet, A F

2003-03-01

This paper covers the elaboration of a general class of multitype branching processes for modeling in a branching population, the evolution of a disease with horizontal and vertical transmissions. When the size of the population may tend to infinity, normalization must be carried out. As the initial size tends to infinity, the normalized model converges a.s. to a dynamical system the solution of which is the probability law of the state of health for an individual ancestors line. The focal point of this study concerns the transient and asymptotical behaviors of a SIS model with two age classes in a branching population. We will compare the asymptotical probability of extinction on the scale of a finite population and on the scale of an individual in an infinite population: when the rates of transmission are small compared to the rate of renewing the population of susceptibles, the two models lead to a.s. extinction, giving consistent results, which no longer applies to the opposite situation of important transmissions. In that case the size of the population plays a crucial role in the spreading of the disease.

Branched Crystalline Patterns of Poly(ε-caprolactone) and Poly(4-hydroxystyrene) Blends Thin Films.

PubMed

Hou, Chunyue; Yang, Tianbo; Sun, Xiaoli; Ren, Zhongjie; Li, Huihui; Yan, Shouke

2016-01-14

The chain organization of poly(ε-caprolactone) (PCL) in its blend with poly(4-hydroxystyrene) (PVPh) in thin films (130 ± 10 nm) has been revealed by grazing incident infrared (GIIR) spectroscopy. It can be found that PCL chains orient preferentially in the surface-normal direction and crystallization occurs simultaneously. The morphology of the PCL/PVPh blends films can be identified by optical microscopy (OM). When crystallized at 35 °C, the blends film shows a seaweed-like structure and becomes more open with increasing PVPh content. In contrast, when crystallized at higher temperatures, i.e., 40 and 45 °C, dendrites with apparent crystallographically favored branches can be observed. This characteristic morphology indicates that the diffusion-limited aggregation (DLA) process controls the crystal growth in the blends films. The detailed lamellar structure can be revealed by the height images of atomic force microscopy (AFM), i.e., the crystalline branches are composed of overlayered flat-on lamellae. The branch width has been found to be dependent on the supercooling and PVPh content. This result differs greatly from pure PCL, in which case the crystal patterns controlled by DLA process developed in ultrathin film or monolayers of several nanometers. In the PCL/PVPh blends case, the strong intermolecular interactions and the dilution effect of PVPh should contribute to these results. That is to say, the mobility of PCL chains can be retarded and diffusion of them to the crystal growth front slows down greatly, even though the film thickness is far more than the lamellar thickness of PCL.

A systematic account of the genus Plagiostoma (Gnomoniaceae, Diaporthales) based on morphology, host-associations, and a four gene phylogeny

USDA-ARS?s Scientific Manuscript database

The genus Plagiostoma inhabits leaves and branches of a range of woody and herbaceous plant families in the temperate northern hemisphere. Based on analyses of morphological, cultural, and molecular data, Plagiostoma is reviewed and monographed. The morphological data include shape and size of perit...

Pinus ponderosa: geographic races and subspecies based on morphological variation

Treesearch

Robert Z. Callaham

2013-01-01

Morphological variation of ponderosa pine (Pinus ponderosa Dougl. ex Laws.), growing north of Mexico, is described. A map shows distributions of five putative races that are analyzed and discussed. Characteristics of branches, shoots, and needles were measured for 10 or fewer trees growing on 147 plots located at 1,500-ft elevational intervals...

Materials Test Branch

NASA Technical Reports Server (NTRS)

Gordon, Gail

2012-01-01

The Materials Test Branch resides at Marshall Space Flight Center's Materials and Processing laboratory and has a long history of supporting NASA programs from Mercury to the recently retired Space Shuttle. The Materials Test Branch supports its customers by supplying materials testing expertise in a wide range of applications. The Materials Test Branch is divided into three Teams, The Chemistry Team, The Tribology Team and the Mechanical Test Team. Our mission and goal is to provide world-class engineering excellence in materials testing with a special emphasis on customer service.

NCO Production Management Branch

Science.gov Websites

Climate Climate Prediction Climate Archives Weather Safety Storm Ready NOAA Central Library Photo Library Management Branch Production Management Branch About the Production Management Branch NCO REQUEST FOR CHANGE (RFC) DATABASE ACCESS NCO Request For Change (RFC) Archive [For INTERNAL Use Only] NCO Request For

Overexpression of Robo2 causes defects in the recruitment of metanephric mesenchymal cells and ureteric bud branching morphogenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ji, Jiayao; Medical College of NanKai University, Tianjin; Li, Qinggang

2012-05-11

Highlights: Black-Right-Pointing-Pointer Overexpression of Robo2 caused reduced UB branching and glomerular number. Black-Right-Pointing-Pointer Fewer MM cells surrounding the UB after overexpression of Robo2 in vitro. Black-Right-Pointing-Pointer No abnormal Epithelial Morphology of UB or apoptosis of mm cells in the kidney. Black-Right-Pointing-Pointer Overexpression of Robo2 affected MM cells migration and caused UB deficit. Black-Right-Pointing-Pointer The reduced glomerular number can also be caused by fewer MM cells. -- Abstract: Roundabout 2 (Robo2) is a member of the membrane protein receptor family. The chemorepulsive effect of Slit2-Robo2 signaling plays vital roles in nervous system development and neuron migration. Slit2-Robo2 signaling is also importantmore » for maintaining the normal morphogenesis of the kidney and urinary collecting system, especially for the branching of the ureteric bud (UB) at the proper site. Slit2 or Robo2 mouse mutants exhibit multilobular kidneys, multiple ureters, and dilatation of the ureter, renal pelvis, and collecting duct system, which lead to vesicoureteral reflux. To understand the effect of Robo2 on kidney development, we used microinjection and electroporation to overexpress GFP-Robo2 in an in vitro embryonic kidney model. Our results show reduced UB branching and decreased glomerular number after in vitro Robo2 overexpression in the embryonic kidneys. We found fewer metanephric mesenchymal (MM) cells surrounding the UB but no abnormal morphology in the branching epithelial UB. Meanwhile, no significant change in MM proliferation or apoptosis was observed. These findings indicate that Robo2 is involved in the development of embryonic kidneys and that the normal expression of Robo2 can help maintain proper UB branching and glomerular morphogenesis. Overexpression of Robo2 leads to reduced UB branching caused by fewer surrounding MM cells, but MM cell apoptosis is not involved in this effect. Our study demonstrates

Limitation on the use of the horizontal clinostat as a gravity compensator

NASA Technical Reports Server (NTRS)

Brown, A. H.; Dahl, A. O.; Chapman, D. K.

1975-01-01

If the horizontal clinostat effectively compensates for the influence of the gravity vector on the rotating plant, it makes the plant unresponsive to whatever chronic acceleration may be applied transverse to the axis of clinostat rotation. This was tested by centrifuging plants while they were growing on clinostats. For a number of morphological endpoints of development, the results depended on the magnitude of the applied g-force. Gravity compensation by the clinostat was incomplete, and this conclusion is in agreement with results of satellite experiments which are reviewed.

Standard Giant Branches in the Washington Photometric System

NASA Technical Reports Server (NTRS)

Geisler, Doug; Sarajedini, Ata

1998-01-01

We have obtained CCD photometry in the Washington system C, T(sub 1) filters for some 850,000 objects associated with 10 Galactic globular clusters and 2 old open clusters. These clusters have well-known metal abundances, spanning a metallicity range of 2.5 dex from [Fe/H] approx -2.25 to +0.25 at a spacing of approx. 0.2 dex. Two independent observations were obtained for each cluster and internal checks, as well as external comparisons with existing photoelectric photometry, indicate that the final colors and magnitudes have overall uncertainties of 0.03 mag. Analogous to the method employed by Da Costa and Armandroff for V, I photometry , we then proceed to construct standard ((M(sub T),(C - T(sub 1))(sub 0)) giant branches for these clusters adopting the Lee et distance scale, using some 350 stars per globular cluster to define the giant branch. We then determine the metallicity sensitivity of the ((C - T(sub 1))(sub 0) color at a given M((sub T)(sub 1)) value. The Washington system technique is found to have three times the metallicity sensitivity of the V, I technique. At M((sub T)(sub 1)) = -2 (about a magnitude below the tip of the giant branch, roughly equivalent to M(sub I) = -3), the giant branches of 47 Tuc and M15 are separated by 1.16 magnitudes in (V - l)(sub 0) and only 0.38 magnitudes in (V - I)(sub 0). Thus, for a given photometric accuracy, metallicities can be determined three times more precisely with the Washington technique. We find a linear relationship between (C - T(sub l)(sub 0) (at M(sub T)(sub 1) = -2) and metallicity exists over the full metallicity range, with an rms of only 0.04 dex. We also derive metallicity calibrations for M(sub T)(sub 1) = -2.5 and -1.5, as well as for two other metallicity scales. The Washington technique retains almost the same metallicity sensitivity at faint magnitudes , and indeed the standard giant branches are still well separated even below the horizontal branch. The photometry is used to set upper

Overexpression of STARCH BRANCHING ENZYME II increases short-chain branching of amylopectin and alters the physicochemical properties of starch from potato tuber.

PubMed

Brummell, David A; Watson, Lyn M; Zhou, Jun; McKenzie, Marian J; Hallett, Ian C; Simmons, Lyall; Carpenter, Margaret; Timmerman-Vaughan, Gail M

2015-04-29

Starch is biosynthesised by a complex of enzymes including various starch synthases and starch branching and debranching enzymes, amongst others. The role of all these enzymes has been investigated using gene silencing or genetic knockouts, but there are few examples of overexpression due to the problems of either cloning large genomic fragments or the toxicity of functional cDNAs to bacteria during cloning. The aim of this study was to investigate the function of potato STARCH BRANCHING ENZYME II (SBEII) using overexpression in potato tubers. A hybrid SBEII intragene consisting of potato cDNA containing a fragment of potato genomic DNA that included a single intron was used in order to prevent bacterial translation during cloning. A population of 20 transgenic potato plants exhibiting SBEII overexpression was generated. Compared with wild-type, starch from these tubers possessed an increased degree of amylopectin branching, with more short chains of degree of polymerisation (DP) 6-12 and particularly of DP6. Transgenic lines expressing a GRANULE-BOUND STARCH SYNTHASE (GBSS) RNAi construct were also generated for comparison and exhibited post-transcriptional gene silencing of GBSS and reduced amylose content in the starch. Both transgenic modifications did not affect granule morphology but reduced starch peak viscosity. In starch from SBEII-overexpressing lines, the increased ratio of short to long amylopectin branches facilitated gelatinisation, which occurred at a reduced temperature (by up to 3°C) or lower urea concentration. In contrast, silencing of GBSS increased the gelatinisation temperature by 4°C, and starch required a higher urea concentration for gelatinisation. In lines with a range of SBEII overexpression, the magnitude of the increase in SBEII activity, reduction in onset of gelatinisation temperature and increase in starch swollen pellet volume were highly correlated, consistent with reports that starch swelling is greatly dependent upon the

Combining living anionic polymerization with branching reactions in an iterative fashion to design branched polymers.

PubMed

Higashihara, Tomoya; Sugiyama, Kenji; Yoo, Hee-Soo; Hayashi, Mayumi; Hirao, Akira

2010-06-16

This paper reviews the precise synthesis of many-armed and multi-compositional star-branched polymers, exact graft (co)polymers, and structurally well-defined dendrimer-like star-branched polymers, which are synthetically difficult, by a commonly-featured iterative methodology combining living anionic polymerization with branched reactions to design branched polymers. The methodology basically involves only two synthetic steps; (a) preparation of a polymeric building block corresponding to each branched polymer and (b) connection of the resulting building unit to another unit. The synthetic steps were repeated in a stepwise fashion several times to successively synthesize a series of well-defined target branched polymers. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrologic and hydraulic analyses at Akin Branch and Cayce Valley Branch, Columbia, Tennessee

USGS Publications Warehouse

Outlaw, George S.

1993-01-01

The U.S. Geological Survey, in cooperation with the City of Columbia, Tennessee, conducted hydrologic and hydraulic analyses at Akin Branch and Cayce Valley Branch in the Little Bigby Creek watershed, Columbia, Tennessee, from 1990 through 1991. Results of the analyses can be used by city planners in the development of plans to replace several deteriorating and inadequate drainage structures. Akin Branch and Cayce Valley Branch drain small watersheds of 1.69 and 1.04 square miles, respectively. Flood discharges for 5-, lo-, and 25-year recurrence-interval storm events were calculated at the stream mouths using flood-frequency relations developed for use at small urban streams in Tennessee. For each stream, flood discharges at locations upstream from the mouth were calculated by subdividing the watershed and assigning a percentage of the discharge at the mouth, based on drainage area, to each subarea. Flood profiles for the selected recurrence-interval flood discharges were simulated for Akin Branch and Cayce Valley Branch for existing conditions and conditions that might exist if drainage improvements such as larger culverts and bridges and channel improvements are constructed. The results of the simulations were used to predict changes in flood elevations that might result from such drainage improvements. Analyses indicate that reductions in existing flood elevations of as much as 2.1 feet for the 5-year flood at some sites on Akin Branch and as much as 3.8 feet for the 5-year flood at some sites on Cayce Valley Branch might be expected with the drainage improvements.

Fine-Branched Ridges

NASA Image and Video Library

2015-10-14

This image from NASA Mars Reconnaissance Orbiter spacecraft shows numerous branching ridges with various degrees of sinuosity. These branching forms resemble tributaries funneling and draining into larger channel trunks towards the upper portion of the scene. The raised relief of these branching ridges suggests that these are ancient channels are inverted due to lithification and cementation of the riverbed sediment, which made it more resistant to erosion than the surrounding material. Wind-blown bedforms are abundant and resemble small ridges that are aligned in an approximately north-south direction. http://photojournal.jpl.nasa.gov/catalog/PIA20006

Horizontal traumatic laceration of the pancreas head: A rare case report.

PubMed

Nanashima, Atsushi; Imamura, Naoya; Tsuchimochi, Yuki; Hamada, Takeomi; Yano, Kouichi; Hiyoshi, Masahide; Fujii, Yoshiro; Kawano, Fumiaki; MitsuruTamura

2017-01-01

This case report is intended to inform acute care surgeons about treating rare horizontal laceration of the pancreas head caused by blunt trauma. A 57-year-old woman who sustained blunt abdominal trauma during a car crash was transported to the emergency center of our hospital with unstable vital signs due to hemorrhagic shock. Computed tomography showed transection of the pancreas head and massive intra-abdominal hemorrhage. She was referred for emergency surgery because of a transient response. Laparotomy at five hours after the accident initially revealed consistent massive bleeding from branches of the superior mesenteric artery and vein, which we resolved by suturing the vessels without damaging the main trunks. A horizontal laceration and complete transection of the pancreatic head were then confirmed but the main pancreatic duct remained intact. The lower part of the pancreatic head including the uncus with the attached part of the duodenum was resected, and the pancreatic stump remaining after transection was fixed by suturing. The jejunal limb was attached to the remnant duodenum by side-to-side functional anastomosis. Although gastric emptying was delayed for one month after surgery, the postoperative course was good and the patient recovered at three months thereafter. The embryonic border of pancreas head accompanied with pancreatic divisum was considered for this laceration without disruption of the main pancreatic duct. Blunt pancreatic trauma usually causes vertical transection and thus, horizontal transection is considered rare. The embryological anatomical border between the ventral and dorsal pancreas due to pancreatic divisum was supposed to be transected and therefore the main pancreatic duct was not damaged. Hemorrhagic shock and rare pancreatic head trauma were treated by appropriate intraoperative management. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

An Anatomical Assessment of Branch Abscission and Branch-base Hydraulic Architecture in the Endangered Wollemia nobilis

PubMed Central

Burrows, G. E.; Meagher, P. F.; Heady, R. D.

2007-01-01

Background and Aims The branch-base xylem structure of the endangered Wollemia nobilis was anatomically investigated. Wollemia nobilis is probably the only extant tree species that produces only first-order branches and where all branches are cleanly abscised. An investigation was carried out to see if these unusual features might influence branch-base xylem structure and water supply to the foliage. Methods The xylem was sectioned at various distances along the branch bases of 6-year-old saplings. Huber values and relative theoretical hydraulic conductivities were calculated for various regions of the branch base. Key Results The most proximal branch base featured a pronounced xylem constriction. The constriction had only 14–31 % (average 21 %) of the cross-sectional area and 20–42 % (average 28 %) of the theoretical hydraulic conductivity of the more distal branch xylem. Wollemia nobilis had extremely low Huber values for a conifer. Conclusions The branch-base xylem constriction would appear to facilitate branch abscission, while the associated Huber values show that W. nobilis supplies a relatively large leaf area through a relatively small diameter ‘pipe’. It is tempting to suggest that the pronounced decline of W. nobilis in the Tertiary is related to its unusual branch-base structure but physiological studies of whole plant conductance are still needed. PMID:17272303

Convergence among cave catfishes: long-branch attraction and a Bayesian relative rates test.

PubMed

Wilcox, T P; García de León, F J; Hendrickson, D A; Hillis, D M

2004-06-01

Convergence has long been of interest to evolutionary biologists. Cave organisms appear to be ideal candidates for studying convergence in morphological, physiological, and developmental traits. Here we report apparent convergence in two cave-catfishes that were described on morphological grounds as congeners: Prietella phreatophila and Prietella lundbergi. We collected mitochondrial DNA sequence data from 10 species of catfishes, representing five of the seven genera in Ictaluridae, as well as seven species from a broad range of siluriform outgroups. Analysis of the sequence data under parsimony supports a monophyletic Prietella. However, both maximum-likelihood and Bayesian analyses support polyphyly of the genus, with P. lundbergi sister to Ictalurus and P. phreatophila sister to Ameiurus. The topological difference between parsimony and the other methods appears to result from long-branch attraction between the Prietella species. Similarly, the sequence data do not support several other relationships within Ictaluridae supported by morphology. We develop a new Bayesian method for examining variation in molecular rates of evolution across a phylogeny.

Pulsating hot O subdwarfs in ω Centauri: mapping a unique instability strip on the extreme horizontal branch

NASA Astrophysics Data System (ADS)

Randall, S. K.; Calamida, A.; Fontaine, G.; Monelli, M.; Bono, G.; Alonso, M. L.; Van Grootel, V.; Brassard, P.; Chayer, P.; Catelan, M.; Littlefair, S.; Dhillon, V. S.; Marsh, T. R.

2016-05-01

We present the results of an extensive survey for rapid pulsators among Extreme Horizontal Branch (EHB) stars in ω Cen. The observations performed consist of nearly 100 h of time-series photometry for several off-centre fields of the cluster, as well as low-resolution spectroscopy for a partially overlapping sample. We obtained photometry for some 300 EHB stars, for around half of which we are able to recover light curves of sufficient quality to either detect or place meaningful non-detection limits for rapid pulsations. Based on the spectroscopy, we derive reliable values of log g, Teff and log N(He) /N(H) for 38 targets, as well as good estimates of the effective temperature for another nine targets, whose spectra are slightly polluted by a close neighbour in the image. The survey uncovered a total of five rapid variables with multi-periodic oscillations between 85 and 125 s. Spectroscopically, they form a homogeneous group of hydrogen-rich subdwarf O stars clustered between 48 000 and 54 000 K. For each of the variables we are able to measure between two and three significant pulsations believed to constitute independent harmonic oscillations. However, the interpretation of the Fourier spectra is not straightforward due to significant fine structure attributed to strong amplitude variations. In addition to the rapid variables, we found an EHB star with an apparently periodic luminosity variation of ~2700 s, which we tentatively suggest may be caused by ellipsoidal variations in a close binary. Using the overlapping photometry and spectroscopy sample we are able to map an empirical ω Cen instability strip in log g - Teff space. This can be directly compared to the pulsation driving predicted from the Montréal "second-generation" models regularly used to interpret the pulsations in hot B subdwarfs. Extending the parameter range of these models to higher temperatures, we find that the region where p-mode excitation occurs is in fact bifurcated, and the well

Morphology and dynamics of explosive vents

NASA Astrophysics Data System (ADS)

Gisler, Galen R.; Galland, Olivier; Haug, Øystein T.

2014-05-01

Eruptive processes in nature produce a wide variety of morphologies, including cone sheets, dykes, sills, and pipes. The choice of a particular eruptive style is determined partly by local inhomogeneities, and partly by the gross overall properties of the country rock and the physical properties of the eruptive fluid. In this study we report on experimental and numerical designed to capture a range of morphologies in an eruptive system. Using dimensional analysis we link the experimental and numerical work together and draw implications for field studies. Our experimental work uses silica flour in a Hele-Shaw cell, with air as the eruptive fluid. A phase diagram demonstrates a separation between two distinct morphologies, with vertical structures occurring at high pressure or low depth of fill and diagonal ones at low pressure or high depth of fill. In the numerical work the eruptive fluid is a mixture of basaltic magma, supercritical water, and carbon dioxide, and the ambient material is a fill of basalt with varying material properties. In the numerical work we see three distinct morphologies: vertical pipes are produced at high pressures and softer backgrounds, diagonal pipes at lower pressures and stiffer backgrounds, while horizontal sills are produced in intermediate regimes.

The CCD photometry of the globular cluster Palomar 1.

NASA Astrophysics Data System (ADS)

Borissova, J.; Spassova, N.

1995-04-01

A CCD photometry of the halo cluster Palomar 1 is presented in the Thuan-Gunn photometric system. The principal sequences of the color-magnitude diagrams are delineated in different spectral bands. The color-magnitude diagrams of the cluster show a well defined red horizontal branch, a subgiant branch and a main-sequence down to about two magnitudes below the main sequence turnoff. The giant branch is absent and the brightest stars are the horizontal branch stars. The age of the cluster determined by comparison with the isochrones of Bell & Vanden Berg (1987) is consistent with an age in the interval 12-14Gyr. A distance modulus of (m-M)_g0_=15.38+/-0.15 magnitude and E(g-r)=0.16 has been derived. An estimate of the cluster structural parameters such as core radius and concentration parameter gives r_c_=1.5pc and c=1.46. A mass estimate of 1.1 10^3^Msun_ and a mass-to-light ratio of 1.79 have been obtained using King's (1966) method. The morphology of color-magnitude diagrams allows Pal 1 to be interpreted as probably a globular cluster rather than an old open one.

Horizontal electric fields from lightning return strokes

NASA Technical Reports Server (NTRS)

Thomson, E. M.; Medelius, P. J.; Rubinstein, M.; Uman, M. A.; Johnson, J.

1988-01-01

An experiment to measure simultaneously the wideband horizontal and vertical electric fields from lightning return strokes is described. Typical wave shapes of the measured horizontal and vertical fields are presented, and the horizontal fields are characterized. The measured horizontal fields are compared with calculated horizontal fields obtained by applying the wavetilt formula to the vertical fields. The limitations and sources of error in the measurement technique are discussed.

Constraints on the Distance Moduli, Helium, and Metal Abundances, and Ages of Globular Clusters from Their RR Lyrae and Non-variable Horizontal Branch Stars. II. Multiple Stellar Populations in 47 Tuc, M3, and M13

NASA Astrophysics Data System (ADS)

Denissenkov, Pavel A.; VandenBerg, Don A.; Kopacki, Grzegorz; Ferguson, Jason W.

2017-11-01

We present a new set of horizontal branch (HB) models computed with the MESA stellar evolution code. The models adopt α-enhanced Asplund et al. metal mixtures and include the gravitational settling of He. They are used in our HB population synthesis tool to generate theoretical distributions of HB stars in order to describe the multiple stellar populations in the globular clusters 47 Tuc, M3, and M13. The observed HB in 47 Tuc is reproduced very well by our simulations for [{Fe}/{{H}}]=-0.70 and [α /{Fe}]=+0.4 if the initial helium mass fraction varies by {{Δ }}{Y}0˜ 0.03, and approximately 21%, 37%, and 42% of the stars have {Y}0=0.257, 0.270, and 0.287, respectively. These simulations yield {(m-M)}V=13.27, implying an age near 13.0 Gyr. In the case of M3 and M13, our synthetic HBs for [{Fe}/{{H}}]=-1.55 and [α /{Fe}]=0.4 match the observed ones quite well if M3 has {{Δ }}{Y}0˜ 0.01 and {(m-M)}V=15.02, resulting in an age of 12.6 Gyr, whereas M13 has {{Δ }}{Y}0˜ 0.08 and {(m-M)}V=14.42, implying an age of 12.9 Gyr. Mass loss during giant branch evolution and {{Δ }}{Y}0 appear to be the primary second parameters for M3 and M13. New observations for seven of the nine known RR Lyrae in M13 are also reported. Surprisingly, periods predicted for the c-type variables tend to be too high (by up to ˜0.1 days).

Chalk play tops Gulf Coast horizontal scene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-11-18

This paper reports on horizontal drilling in the Cretaceous Austin chalk of Texas which dominates news of U.S. Gulf Coast horizontal action. In spite of a significant decline in horizontal drilling in Texas-the Texas Railroad Commission reported a 15 unit decline in the number of permits to drill horizontal wells during the third quarter-operators in East and South Texas continue to expand plays and develop new ones. The Cretaceous Bruda may be gaining some respect as a horizontal target in Texas. Elsewhere on the Gulf Coast, Mississippi soon will see more action on the horizontal drilling front.

A morphological and functional basis for maximum prey size in piscivorous fishes

PubMed Central

Bellwood, David R.

2017-01-01

Fish predation is important in shaping populations and community structure in aquatic systems. These predator-prey interactions can be influenced by environmental, behavioural and morphological factors. Morphological constraints influence the feeding performance of species, and interspecific differences can thus affect patterns of resource use. For piscivorous fishes that swallow prey whole, feeding performance has traditionally been linked to three key morphological constraints: oral gape, pharyngeal gape, and the cleithral gape. However, other constraints may be important. We therefore examine 18 potential morphological constraints related to prey capture and processing, on four predatory species (Cephalopholis urodeta, Paracirrhites forsteri, Pterois volitans, Lates calcarifer). Aquarium-based experiments were then carried out to determine capture and processing behaviour and maximum prey size in two focal species, C. urodeta and P. forsteri. All four species showed a progressive decrease in gape measurements from anterior to posterior with oral gape ≥ buccal ≥ pharyngeal ≥ pectoral girdle ≥ esophagus ≥ stomach. C. urodeta was able to process prey with a maximum depth of 27% of the predators’ standard length; for P. forsteri it was 20%. C. urodeta captured prey head-first in 79% of successful strikes. In P. forsteri head-first was 16.6%, mid-body 44.4%, and tail-first 38.8%. Regardless of capture mode, prey were almost always swallowed head first and horizontally in both focal species. Most internal measurements appeared too small for prey to pass through. This may reflect the compressibility of prey, i.e. their ability to be dorsoventrally compressed during swallowing movements. Despite examining all known potential morphological constraints on prey size, horizontal maxillary oral gape in a mechanically stretched position appears to be the main morphological variable that is likely to affect maximum prey size and resource use by these predatory

Analysis of interface crack branching

NASA Technical Reports Server (NTRS)

Ballarini, R.; Mukai, D. J.; Miller, G. R.

1989-01-01

A solution is presented for the problem of a finite length crack branching off the interface between two bonded dissimilar isotropic materials. Results are presented in terms of the ratio of the energy release rate of a branched interface crack to the energy release rate of a straight interface crack with the same total length. It is found that this ratio reaches a maximum when the interface crack branches into the softer material. Longer branches tend to have smaller maximum energy release rate ratio angles indicating that all else being equal, a branch crack will tend to turn back parallel to the interface as it grows.

Portable Horizontal-Drilling And Positioning Device

NASA Technical Reports Server (NTRS)

Smigocki, Edmund; Johnson, Clarence

1988-01-01

Portable horizontal-drilling and positioning device, constructed mainly of off-the-shelf components, accurately drills horizontal small holes in irregularly shaped objects. Holes precisely placed and drilled in objects that cannot be moved to shop area. New device provides three axes of movement while maintaining horizontal drilling.

GLABROUS INFLORESCENCE STEMS regulates trichome branching by genetically interacting with SIM in Arabidopsis.

PubMed

Sun, Li-Li; Zhou, Zhong-Jing; An, Li-Jun; An, Yan; Zhao, Yong-Qin; Meng, Xiao-Fang; Steele-King, Clare; Gan, Yin-Bo

2013-07-01

Arabidopsis trichomes are large branched single cells that protrude from the epidermis. The first morphological indication of trichome development is an increase in nuclear content resulting from an initial cycle of endoreduplication. Our previous study has shown that the C2H2 zinc finger protein GLABROUS INFLORESCENCE STEMS (GIS) is required for trichome initiation in the inflorescence organ and for trichome branching in response to gibberellic acid signaling, although GIS gene does not play a direct role in regulating trichome cell division. Here, we describe a novel role of GIS, controlling trichome cell division indirectly by interacting genetically with a key endoreduplication regulator SIAMESE (SIM). Our molecular and genetic studies have shown that GIS might indireclty control cell division and trichome branching by acting downstream of SIM. A loss of function mutation of SIM signficantly reduced the expression of GIS. Futhermore, the overexpression of GIS rescued the trichome cluster cell phenotypes of sim mutant. The gain or loss of function of GIS had no significant effect on the expression of SIM. These results suggest that GIS may play an indirect role in regulating trichome cell division by genetically interacting with SIM.

[Croatian Medical Association--Branch Zagreb].

PubMed

Kaić, Zvonimir; Sain, Snjezana; Gulić, Mirjana; Mahovlić, Vjekoslav; Krznarić, Zeljko

2014-01-01

The available literature shows us that "Druztvo ljeciteljah u Zagrebus (the Society of Healers in Zagreb) was founded as far back as the year 1845 by a total of thirteen members. This data allows us to follow the role of doctors and health workers in Zagreb through their everyday profession, research, organizational and social work as well as management through a period of over one hundred to seventy years. The Branch Zagreb was active before the official establishment of subsidiaries of CMA which is evident from the minutes of the regular annual assembly of the Croatian Medical Association on 21 March 1948. Until the end of 1956, there was no clear division of labor, functions and competencies between the Branch and the Main Board. Their actions were instead consolidated and the Branch operated within and under the name of Croatian Medical Association. In that year the Branch became independent. The Branch Zagreb is the largest and one of the most active branches of the Croatian Medical Association. At the moment, the Branch brings together 3621 members, regular members--doctors of medicine (2497), doctors of dental medicine (384), retired physicians (710), and associate members (30 specialists with higher education who are not doctors). The Branch is especially accomplished in its activities in the area of professional development of its members and therefore organizes a series of scientific conferences in the framework of continuous education of physicians, allowing its members to acquire necessary points for the extension of their operating license. The choir "Zagrebacki lijecnici pjevaci" (Zagreb Physicians' Choir) of the Croatian Medical Music Society of the CMA and its activities are inseparable from the Branch Zagreb. The Branch is firmly linked to the parent body, the CMA, and thus has a visible impact on the strategy and the activities of the Association as a whole. Most professional societies of the CMA have their headquarters in Zagreb and this is

Age, environment, object recognition and morphological diversity of GFAP-immunolabeled astrocytes.

PubMed

Diniz, Daniel Guerreiro; de Oliveira, Marcus Augusto; de Lima, Camila Mendes; Fôro, César Augusto Raiol; Sosthenes, Marcia Consentino Kronka; Bento-Torres, João; da Costa Vasconcelos, Pedro Fernando; Anthony, Daniel Clive; Diniz, Cristovam Wanderley Picanço

2016-10-10

Few studies have explored the glial response to a standard environment and how the response may be associated with age-related cognitive decline in learning and memory. Here we investigated aging and environmental influences on hippocampal-dependent tasks and on the morphology of an unbiased selected population of astrocytes from the molecular layer of dentate gyrus, which is the main target of perforant pathway. Six and twenty-month-old female, albino Swiss mice were housed, from weaning, in a standard or enriched environment, including running wheels for exercise and tested for object recognition and contextual memories. Young adult and aged subjects, independent of environment, were able to distinguish familiar from novel objects. All experimental groups, except aged mice from standard environment, distinguish stationary from displaced objects. Young adult but not aged mice, independent of environment, were able to distinguish older from recent objects. Only young mice from an enriched environment were able to distinguish novel from familiar contexts. Unbiased selected astrocytes from the molecular layer of the dentate gyrus were reconstructed in three-dimensions and classified using hierarchical cluster analysis of bimodal or multimodal morphological features. We found two morphological phenotypes of astrocytes and we designated type I the astrocytes that exhibited significantly higher values of morphological complexity as compared with type II. Complexity = [Sum of the terminal orders + Number of terminals] × [Total branch length/Number of primary branches]. On average, type I morphological complexity seems to be much more sensitive to age and environmental influences than that of type II. Indeed, aging and environmental impoverishment interact and reduce the morphological complexity of type I astrocytes at a point that they could not be distinguished anymore from type II. We suggest these two types of astrocytes may have different physiological roles

Limitation on the Use of the Horizontal Clinostat as a Gravity Compensator 123

PubMed Central

Brown, Allan H.; Dahl, A. O.; Chapman, D. K.

1976-01-01

If the horizontal clinostat effectively compensates for the influence of the gravity vector on the rotating plant, it should make the plant unresponsive to whatever chronic acceleration may be applied transverse to the axis of clinostat rotation. This was tested by centrifuging plants while they were growing on clinostats. For a number of morphological end-points of development the results depended on the magnitude of the applied g-force. Therefore, gravity compensation by the clinostat was incomplete. This conclusion is in agreement with results of satellite experiments which are reviewed. PMID:16659631

Near-term Horizontal Launch for Flexible Operations: Results of the DARPA/NASA Horizontal Launch Study

NASA Technical Reports Server (NTRS)

Bartolotta, Paul A.; Wilhite, Alan W.; Schaffer, Mark G.; Huebner, Lawrence D.; Voland, Randall T.; Voracek, David F.

2012-01-01

Horizontal launch has been investigated for 60 years by over 130 different studies. During this time only one concept, Pegasus, has ever been in operation. The attractiveness of horizontal launch is the capability to provide a "mobile launch pad" that can use existing aircraft runways, cruise above weather, loiter for mission instructions, and provide precise placement for orbital intercept, rendezvous, or reconnaissance. A jointly sponsored study by DARPA and NASA, completed in 2011, explored the trade space of horizontal launch system concepts which included an exhaustive literature review of the past 70 years. The Horizontal Launch Study identified potential near- and mid-term concepts capable of delivering 15,000 lb payloads to a 28.5 due East inclination, 100 nautical-mile low-Earth orbit. Results are presented for a range of near-term system concepts selected for their availability and relatively low design, development, test, and evaluation (DDT&E) costs. This study identified a viable low-cost development path forward to make a robust and resilient horizontal launch capability a reality.

Randomized branch sampling

Treesearch

Harry T. Valentine

2002-01-01

Randomized branch sampling (RBS) is a special application of multistage probability sampling (see Sampling, environmental), which was developed originally by Jessen [3] to estimate fruit counts on individual orchard trees. In general, the method can be used to obtain estimates of many different attributes of trees or other branched plants. The usual objective of RBS is...

EVOLUTION OF THE CROSS-CORRELATION AND TIME LAG OF 4U 1735-44 ALONG THE BRANCHES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lei Yajuan; Zhang Haotong; Zhang Chengmin

We analyze the cross-correlation function between the soft and hard X-rays of atoll source 4U 1735-44 with RXTE data, and find anti-correlated soft and hard time lags of about a hecto-second. In the island state, the observations do not show any obvious correlations, and most observations of the banana branch show a positive correlation. However, anti-correlations are detected in the upper banana branch. These results are different from those of Z-sources (Cyg X-2, GX 5-1), where anti-correlations are detected in the horizontal branch and upper normal branch. In this case, the lag timescales of both this atoll and Z-sources aremore » found to be similar, at a magnitude of several tens to hundreds of seconds. As a comparison, it is noted that anti-correlated lags lasting thousands of seconds have been reported from several black hole candidates in their intermediate states. In addition, for an observation containing four segments that show positive or anti-correlation, we analyze the spectral evolution with the hybrid model. In the observation, the anti-correlation is detected at the highest flux. The fitting results show that the Comptonized component is not the lowest at the highest flux, which suggests that the anti-correlation corresponds to the transition between the soft and hard states. Finally, we compare the corresponding results of atoll source 4U 1735-44 with those observed in Z-sources and black hole candidates, and the possible origins of the anti-correlated time lags are discussed.« less

The Na-O anticorrelation in horizontal branch stars. IV. M 22

NASA Astrophysics Data System (ADS)

Gratton, R. G.; Lucatello, S.; Sollima, A.; Carretta, E.; Bragaglia, A.; Momany, Y.; D'Orazi, V.; Cassisi, S.; Salaris, M.

2014-03-01

We obtained high-resolution spectra for 94 candidate stars belonging to the HB of M 22 with FLAMES. Previous works have indicated that this cluster has split subgiant (SGB) and red giant branches (RGB) and hosts two different stellar populations, differing in overall metal abundance and both exhibiting a Na-O anti-correlation. The HB stars we observed span a restricted temperature range (7800 < Teff < 11 000 K), where about 60% of the HB stars of M 22 are. Within our sample, we can distinguish three groups of stars segregated (though contiguous) in colours: Group 1 (49 stars) is metal-poor, N-normal, Na-poor, and O-rich: our abundances for this (cooler) group match those determined for the primordial group of RGB stars (a third of the total) from previous studies very well. Group 2 (23 stars) is still metal-poor, but it is N- and Na-rich, though only very mildly depleted in O. We can identify this intermediate group as the progeny of the metal-poor RGB stars that occupy an intermediate location along the Na-O anti-correlation and include about 10% of the RGB stars. The third group (20 stars) is metal-rich, Na-rich, and O-rich. This hotter group most likely corresponds to the most O-rich component of the previously found metal-rich RGB population (a quarter of the total). We did not observe any severely O-depleted stars and we think that the progeny of these stars falls on the hotter part of the HB. Furthermore, we found that the metal-rich population is also over-abundant in Sr, in agreement with results for corresponding RGB and SGB stars. However, we do not find any significant variation in the ratio between the sum of N and O abundances to Fe. We do not have C abundances for our stars. There is some evidence of an enhancement of He content for Groups 2 and 3 stars (Y = 0.338 ± 0.014 ± 0.05); the error bar due to systematics is large, but a consistent analysis of data for several GCs confirms that stars in these groups within M 22 are probably overabundant in

Evaluation of popliteal artery branching patterns and a new subclassification of the 'usual' branching pattern.

PubMed

Celtikci, Pinar; Ergun, Onur; Durmaz, Hasan Ali; Conkbayir, Isik; Hekimoglu, Baki

2017-09-01

To determine the frequency of popliteal artery branching variations in a wide study cohort and to investigate the relationship between these variations and infrapopliteal peripheral arterial disease (PAD). A subclassification was proposed for the most encountered type I-A, utilizing tibio-fibular trunk (TFT) length. A total number of 1184 lower extremity digital subtraction angiography (DSA) studies of 669 patients were evaluated. Following exclusion, 863 lower extremity DSA studies (431 right, 432 left) of 545 patients were enrolled. Popliteal artery branching type, patency of anterior tibial artery (ATA), fibular artery (FA) and posterior tibial artery (PTA) in each extremity and TFT length for type I-A extremities were recorded. Percentages of branching patterns, mean length and cut-off value of TFT and incidence of PAD in different types of branching were calculated. Type I-A was the most common type of branching (81.3%). Frequency of branching pattern variation was 18.7%, the most common variation category was category III (12.2%) and the most common variation type was type III-A (5.6%). ATA and PTA had higher percentages of PAD in extremities with variant branching types. Cut-off value of 3 cm for TFT length was proposed in order to subclassify type I-A. Our study cohort presents a higher incidence of popliteal artery branching variations. Some branching variations might have effect on the involvement pattern of the infrapopliteal arteries by PAD. We propose a subclassification for type I-A; type I-A-S (TFT < 3 cm) and type I-A-L (TFT ≥ 3 cm) which might have impact on interventional procedures.

Morphological cladistic study of coregonine fishes

USGS Publications Warehouse

Smith, G.R.; Todd, T.N.

1992-01-01

A cladistic analysis of 50 characters from 26 taxa of coregonine fishes and two outgroup taxa yields a phylogenetic tree with two major branches, best summarized as two genera - Prosopium and Coregonus. Presence of teeth on the palatine, long maxillae, and long supra-maxillae are primitive, whereas loss of teeth, short or notched maxillae, and short supermaxillae are derived traits. P. coulteri and C. huntsmani are morphologically and phylogenetically primitive members of their groups. The widespread species, P. cylindraceum and P. williamsoni are morphologically advanced in parallel with the subgenus Coregonus (whitefishes): they share subterminal mouths, short jaws, and reduced teeth. Prosopium gemmifer parallels the ciscoes, subgenus Leucichthys. The whitefishes, C. ussuriensis, C. lavaretus, C. clupeaformis, and C. nasus are a monophyletic group, the subgenus Coregonus. The subgenus Leucichthys is a diverse, relatively plesiomorphic assemblage, widespread in the Holarctic region. This assemblage includes the inconnu, Stenodus.

Regulation of C. elegans presynaptic differentiation and neurite branching via a novel signaling pathway initiated by SAM-10

PubMed Central

Zheng, Qun; Schaefer, Anneliese M.; Nonet, Michael L.

2011-01-01

Little is known about transcriptional control of neurite branching or presynaptic differentiation, events that occur relatively late in neuronal development. Using the Caenorhabditis elegans mechanosensory circuit as an in vivo model, we show that SAM-10, an ortholog of mammalian single-stranded DNA-binding protein (SSDP), functions cell-autonomously in the nucleus to regulate synaptic differentiation, as well as positioning of, a single neurite branch. PLM mechanosensory neurons in sam-10 mutants exhibit abnormal placement of the neurite branch point, and defective synaptogenesis, characterized by an overextended synaptic varicosity, underdeveloped synaptic morphology and disrupted colocalization of active zone and synaptic vesicles. SAM-10 functions coordinately with Lim domain-binding protein 1 (LDB-1), demonstrated by our observations that: (1) mutations in either gene show similar defects in PLM neurons; and (2) LDB-1 is required for SAM-10 nuclear localization. SAM-10 regulates PLM synaptic differentiation by suppressing transcription of prk-2, which encodes an ortholog of the mammalian Pim kinase family. PRK-2-mediated activities of SAM-10 are specifically involved in PLM synaptic differentiation, but not other sam-10 phenotypes such as neurite branching. Thus, these data reveal a novel transcriptional signaling pathway that regulates neuronal specification of neurite branching and presynaptic differentiation. PMID:21115607

Regulation of C. elegans presynaptic differentiation and neurite branching via a novel signaling pathway initiated by SAM-10.

PubMed

Zheng, Qun; Schaefer, Anneliese M; Nonet, Michael L

2011-01-01

Little is known about transcriptional control of neurite branching or presynaptic differentiation, events that occur relatively late in neuronal development. Using the Caenorhabditis elegans mechanosensory circuit as an in vivo model, we show that SAM-10, an ortholog of mammalian single-stranded DNA-binding protein (SSDP), functions cell-autonomously in the nucleus to regulate synaptic differentiation, as well as positioning of, a single neurite branch. PLM mechanosensory neurons in sam-10 mutants exhibit abnormal placement of the neurite branch point, and defective synaptogenesis, characterized by an overextended synaptic varicosity, underdeveloped synaptic morphology and disrupted colocalization of active zone and synaptic vesicles. SAM-10 functions coordinately with Lim domain-binding protein 1 (LDB-1), demonstrated by our observations that: (1) mutations in either gene show similar defects in PLM neurons; and (2) LDB-1 is required for SAM-10 nuclear localization. SAM-10 regulates PLM synaptic differentiation by suppressing transcription of prk-2, which encodes an ortholog of the mammalian Pim kinase family. PRK-2-mediated activities of SAM-10 are specifically involved in PLM synaptic differentiation, but not other sam-10 phenotypes such as neurite branching. Thus, these data reveal a novel transcriptional signaling pathway that regulates neuronal specification of neurite branching and presynaptic differentiation.

A geological and morphological description of Lakshmi planum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pronin, A.A.; Kadnichanskii, S.A.; Kotel'nikov, V.A.

A morphological description is presented of Lakshmi Planum and its setting, which are a single structure. It is assumed that a mechanism for lifting matter from the planet's interior and spreading it horizontally, which was accompanied by deformation of folding and/or by the formation of tectonic slivers, is the basis for the formation of structure. This allows one to speak of Lakshmi as a local center of radial spreading. The structural scales indicate the participation of asthenospheric flows in its formation.

Horizontal Advanced Tensiometer

DOEpatents

Hubbell, Joel M.; Sisson, James B.

2004-06-22

An horizontal advanced tensiometer is described that allows the monitoring of the water pressure of soil positions, particularly beneath objects or materials that inhibit the use of previous monitoring wells. The tensiometer includes a porous cup, a pressure transducer (with an attached gasket device), an adaptive chamber, at least one outer guide tube which allows access to the desired horizontal position, a transducer wire, a data logger and preferably an inner guide tube and a specialized joint which provides pressure on the inner guide tube to maintain the seal between the gasket of the transducer and the adaptive chamber.

The control of branching morphogenesis

PubMed Central

Iber, Dagmar; Menshykau, Denis

2013-01-01

Many organs of higher organisms are heavily branched structures and arise by an apparently similar process of branching morphogenesis. Yet the regulatory components and local interactions that have been identified differ greatly in these organs. It is an open question whether the regulatory processes work according to a common principle and how far physical and geometrical constraints determine the branching process. Here, we review the known regulatory factors and physical constraints in lung, kidney, pancreas, prostate, mammary gland and salivary gland branching morphogenesis, and describe the models that have been formulated to analyse their impacts. PMID:24004663

Stellar Evolution in NGC 6791: Mass Loss on the Red Giant Branch and the Formation of Low-Mass White Dwarfs

NASA Astrophysics Data System (ADS)

Kalirai, Jasonjot S.; Bergeron, P.; Hansen, Brad M. S.; Kelson, Daniel D.; Reitzel, David B.; Rich, R. Michael; Richer, Harvey B.

2007-12-01

We present the first detailed study of the properties (temperatures, gravities, and masses) of the NGC 6791 white dwarf population. This unique stellar system is both one of the oldest (8 Gyr) and most metal-rich ([Fe/H]~+0.4) open clusters in our Galaxy and has a color-magnitude diagram (CMD) that exhibits both a red giant clump and a much hotter extreme horizontal branch. Fitting the Balmer lines of the white dwarfs in the cluster using Keck/LRIS spectra suggests that most of these stars are undermassive, =0.43+/-0.06 Msolar, and therefore could not have formed from canonical stellar evolution involving the helium flash at the tip of the red giant branch. We show that at least 40% of NGC 6791's evolved stars must have lost enough mass on the red giant branch to avoid the flash and therefore did not convert helium into carbon-oxygen in their core. Such increased mass loss in the evolution of the progenitors of these stars is consistent with the presence of the extreme horizontal branch in the CMD. This unique stellar evolutionary channel also naturally explains the recent finding of a very young age (2.4 Gyr) for NGC 6791 from white dwarf cooling theory; helium-core white dwarfs in this cluster will cool ~3 times slower than carbon-oxygen-core stars, and therefore the corrected white dwarf cooling age is in fact >~7 Gyr, consistent with the well-measured main-sequence turnoff age. These results provide direct empirical evidence that mass loss is much more efficient in high-metallicity environments and therefore may be critical in interpreting the ultraviolet upturn in elliptical galaxies. Data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. Based on observations obtained at the

Self-referential forces are sufficient to explain different dendritic morphologies

PubMed Central

Memelli, Heraldo; Torben-Nielsen, Benjamin; Kozloski, James

2013-01-01

Dendritic morphology constrains brain activity, as it determines first which neuronal circuits are possible and second which dendritic computations can be performed over a neuron's inputs. It is known that a range of chemical cues can influence the final shape of dendrites during development. Here, we investigate the extent to which self-referential influences, cues generated by the neuron itself, might influence morphology. To this end, we developed a phenomenological model and algorithm to generate virtual morphologies, which are then compared to experimentally reconstructed morphologies. In the model, branching probability follows a Galton–Watson process, while the geometry is determined by “homotypic forces” exerting influence on the direction of random growth in a constrained space. We model three such homotypic forces, namely an inertial force based on membrane stiffness, a soma-oriented tropism, and a force of self-avoidance, as directional biases in the growth algorithm. With computer simulations we explored how each bias shapes neuronal morphologies. We show that based on these principles, we can generate realistic morphologies of several distinct neuronal types. We discuss the extent to which homotypic forces might influence real dendritic morphologies, and speculate about the influence of other environmental cues on neuronal shape and circuitry. PMID:23386828

Model-based branching point detection in single-cell data by K-branches clustering

PubMed Central

Chlis, Nikolaos K.; Wolf, F. Alexander; Theis, Fabian J.

2017-01-01

Abstract Motivation The identification of heterogeneities in cell populations by utilizing single-cell technologies such as single-cell RNA-Seq, enables inference of cellular development and lineage trees. Several methods have been proposed for such inference from high-dimensional single-cell data. They typically assign each cell to a branch in a differentiation trajectory. However, they commonly assume specific geometries such as tree-like developmental hierarchies and lack statistically sound methods to decide on the number of branching events. Results We present K-Branches, a solution to the above problem by locally fitting half-lines to single-cell data, introducing a clustering algorithm similar to K-Means. These halflines are proxies for branches in the differentiation trajectory of cells. We propose a modified version of the GAP statistic for model selection, in order to decide on the number of lines that best describe the data locally. In this manner, we identify the location and number of subgroups of cells that are associated with branching events and full differentiation, respectively. We evaluate the performance of our method on single-cell RNA-Seq data describing the differentiation of myeloid progenitors during hematopoiesis, single-cell qPCR data of mouse blastocyst development, single-cell qPCR data of human myeloid monocytic leukemia and artificial data. Availability and implementation An R implementation of K-Branches is freely available at https://github.com/theislab/kbranches. Contact fabian.theis@helmholtz-muenchen.de Supplementary information Supplementary data are available at Bioinformatics online. PMID:28582478

Synthesis of porous carbon nanofiber with bamboo-like carbon nanofiber branches by one-step carbonization process

NASA Astrophysics Data System (ADS)

Yoo, Seung Hwa; Joh, Han-Ik; Lee, Sungho

2017-04-01

Porous carbon nanofibers (PCNFs) with CNF branches (PCNF/bCNF) were synthesized by a simple heat treatment method. Conventional methods to synthesize this unique structure usually follow a typical route, which consists of CNF preparation, catalyst deposition, and secondary CNF growth. In contrast, our method utilized a one-step carbonization process of polymer nanofibers, which were electrospun from a one-pot solution consisted of polyacrylonitrile, polystyrene (PS), and iron acetylacetonate. Various structures of PCNF/CNF were synthesized by changing the solution composition and molecular weight of PS. It was verified that the content and molecular weight of PS were critical for the growth of catalyst particles and subsequent growth of CNF branches. The morphology, phase of catalyst, and carbon structure of PCNF/bCNF were analyzed at different temperature steps during carbonization. It was found that pores were generated by the evaporation of PS and the catalyst particles were formed on the surface of PCNF at 700 °C. The gases originated from the evaporation of PS acted as a carbon source for the growth of CNF branches that started at 900 °C. Finally, when the carbonization process was finished at 1200 °C, uniform and abundant CNF branches were formed on the surface of PCNF.

Horizontal steam generator thermal-hydraulics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ubra, O.; Doubek, M.

1995-09-01

Horizontal steam generators are typical components of nuclear power plants with pressure water reactor type VVER. Thermal-hydraulic behavior of horizontal steam generators is very different from the vertical U-tube steam generator, which has been extensively studied for several years. To contribute to the understanding of the horizontal steam generator thermal-hydraulics a computer program for 3-D steady state analysis of the PGV-1000 steam generator has been developed. By means of this computer program, a detailed thermal-hydraulic and thermodynamic study of the horizontal steam generator PGV-1000 has been carried out and a set of important steam generator characteristics has been obtained. Themore » 3-D distribution of the void fraction and 3-D level profile as functions of load and secondary side pressure have been investigated and secondary side volumes and masses as functions of load and pressure have been evaluated. Some of the interesting results of calculations are presented in the paper.« less

Vegetation survey of PEN Branch wetlands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

A survey was conducted of vegetation along Pen Branch Creek at Savannah River Site (SRS) in support of K-Reactor restart. Plants were identified to species by overstory, understory, shrub, and groundcover strata. Abundance was also characterized and richness and diversity calculated. Based on woody species basal area, the Pen Branch delta was the most impacted, followed by the sections between the reactor and the delta. Species richness for shrub and groundcover strata were also lowest in the delta. No endangered plant species were found. Three upland pine areas were also sampled. In support of K Reactor restart, this report summarizesmore » a study of the wetland vegetation along Pen Branch. Reactor effluent enters Indian Grove Branch and then flows into Pen Branch and the Pen Branch Delta.« less

Vegetation survey of PEN Branch wetlands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-01-01

A survey was conducted of vegetation along Pen Branch Creek at Savannah River Site (SRS) in support of K-Reactor restart. Plants were identified to species by overstory, understory, shrub, and groundcover strata. Abundance was also characterized and richness and diversity calculated. Based on woody species basal area, the Pen Branch delta was the most impacted, followed by the sections between the reactor and the delta. Species richness for shrub and groundcover strata were also lowest in the delta. No endangered plant species were found. Three upland pine areas were also sampled. In support of K Reactor restart, this report summarizesmore » a study of the wetland vegetation along Pen Branch. Reactor effluent enters Indian Grove Branch and then flows into Pen Branch and the Pen Branch Delta.« less

Study of the Local Horizon. (Spanish Title: Estudio del Horizonte Local.) Estudo do Horizonte Local

NASA Astrophysics Data System (ADS)

Ros, Rosa M.

2009-12-01

The study of the horizon is fundamental to easy the first observations of the students at any education center. A simple model, to be developed in each center, allows to easy the study and comprehension of the rudiments of astronomy. The constructed model is presented in turn as a simple equatorial clock, other models (horizontal and vertical) may be constructed starting from it. El estudio del horizonte es fundamental para poder facilitar las primeras observaciones de los alumnos en un centro educativo. Un simple modelo, que debe realizarse para cada centro, nos permite facilitar el estudio y la comprensión de los primeros rudimentos astronómicos. El modelo construido se presenta a su vez como un sencillo modelo de reloj ecuatorial y a partir de él se pueden construir otros modelos (horizontal y vertical). O estudo do horizonte é fundamental para facilitar as primeiras observações dos alunos num centro educativo. Um modelo simples, que deve ser feito para cada centro, permite facilitar o estudo e a compreensão dos primeiros rudimentos astronômicos. O modelo construído apresenta-se, por sua vez, como um modelo simples de relógio equatorial e a partir dele pode-se construir outros modelos (horizontal e vertical)

Applied anatomy of small branches of the portal vein in transverse groove of hepatic hilum.

PubMed

Yan, Pei-ning; Tan, Wei-feng; Yang, Xin-wei; Zhang, Chuan-sen; Jiang, Xiao-qing

2014-12-01

The objective of this study was to provide the morphological details on small branches of the portal vein in transverse groove of hepatic hilum. According to the surgery significance, the small branches of portal vein in transverse groove of hepatic hilum were named as "Short hepatic portal veins (SHPVs)". SHPVs were minutely dissected in 30 adult cadaveric livers. The number, diameter, length, origin points, and entering liver sites of SHPVs were explored and measured. There were 181 SHPVs in 30 liver specimens, including 46% (83/181) from the left portal vein, 31% (56/181) from the bifurcation, and 23% (42/181) from the right portal vein. At the entering liver sites of SHPVs, 22% (40/181) supplied for segment IV, 9% (17/181) for segment V, 4% (7/181) for segment VI, 23% (41/181) for segment VII, and 42% (76/181) for segment I (caudate lobe). There were 6.0 ± 2.4 branches per liver specimen with range 3-12. The mean diameter of SHPVs was 2.25 ± 0.89 mm. The average length of SHPVs was 4.86 ± 2.12 mm. SHPVs widely existed in each liver specimen. The detailed anatomical study of SHPVs could be useful to avoid damaging the short portal branches during hepatic operations, such as isolated or combined caudate lobectomy.

System for Estimating Horizontal Velocity During Descent

NASA Technical Reports Server (NTRS)

Johnson, Andrew; Cheng, Yang; Wilson, Reg; Goguen, Jay; Martin, Alejandro San; Leger, Chris; Matthies, Larry

2007-01-01

The descent image motion estimation system (DIMES) is a system of hardware and software, designed for original use in estimating the horizontal velocity of a spacecraft descending toward a landing on Mars. The estimated horizontal velocity is used in generating rocket-firing commands to reduce the horizontal velocity as part of an overall control scheme to minimize the landing impact. DIMES can also be used for estimating the horizontal velocity of a remotely controlled or autonomous aircraft for purposes of navigation and control.

Understanding Horizontal Governance. Research Brief

ERIC Educational Resources Information Center

Ferguson, Daniel

2009-01-01

Horizontal governance is an umbrella term that covers a range of approaches to policy development, service delivery issues, and management practices. A horizontal initiative may take place across levels of government, across boundaries between units of a single department or agency or among multiple departments or agencies, or across public,…

Morphological characterization of selected balloon films and its effects on balloon performances

NASA Technical Reports Server (NTRS)

Said, Magdi A.

1994-01-01

Morphological characterization of several polyethylene balloon films have been studied using various techniques. The objective is to determine, if any, differentiating structural or morphological features that can be related to the performance of these balloon film materials. The results of the study indicate that the films are composed of either linear low denstiy polyethylene (LLDPE) or low density polyethylene (LDPE). A selective examination of these data imply that films limited degree of branching and larger crystallites size (same % crystallinity) showed good mechanical properties that appear to correlate with their high level of success in balloon flights.

Relation of morphology of electrodeposited zinc to ion concentration profile

NASA Technical Reports Server (NTRS)

May, C. E.; Kautz, H. E.; Sabo, B. B.

1977-01-01

The morphology of electrodeposited zinc was studied with special attention to the ion concentration profile. The initial concentrations were 9M hydroxide ion and 1.21M zincate. Current densities were 6.4 to 64 mA/sq cm. Experiments were run with a horizontal cathode which was observed in situ using a microscope. The morphology of the zinc deposit was found to be a function of time as well as current density; roughly, the log of the transition time from mossy to large crystalline type deposit is inversely proportional to current density. Probe electrodes indicated that the electrolyte in the cathode chamber was mixed by self inducted convection. However, relatively large concentration gradients of the involved species existed across the boundary layer of the cathode. Analysis of the data suggests that the morphology converts from mossy to large crystalline when the hydroxide activity on the cathode surface exceeds about 12 M. Other experiments show that the pulse discharge technique had no effect on the morphology in the system where the bulk concentration of the electrolyte was kept homogeneous via self induced convection.

An Organotypic 3D Assay for Primary Human Mammary Epithelial Cells that Recapitulates Branching Morphogenesis.

PubMed

Linnemann, Jelena R; Meixner, Lisa K; Miura, Haruko; Scheel, Christina H

2017-01-01

We have developed a three-dimensional organotypic culture system for primary human mammary epithelial cells (HMECs) in which the cells are cultured in free floating collagen type I gels. In this assay, luminal cells predominantly form multicellular spheres, while basal/myoepithelial cells form complex branched structures resembling terminal ductal lobular units (TDLUs), the functional units of the human mammary gland in situ. The TDLU-like organoids can be cultured for at least 3 weeks and can then be passaged multiple times. Subsequently, collagen gels can be stained with carmine or by immunofluorescence to allow for the analysis of morphology, protein expression and polarization, and to facilitate quantification of structures. In addition, structures can be isolated for gene expression analysis. In summary, this technique is suitable for studying branching morphogenesis, regeneration, and differentiation of HMECs as well as their dependence on the physical environment.

Prenatal metanephrogenesis of the camel: morphological evidence of epithelial-mesenchymal interaction.

PubMed

Osman, A-H K; Farouk, S M; Eidaroos, H; Abbott, L C; Ahmed, A A

2014-04-01

The present investigation examined histogenesis of epithelial, stromal and angiogenic elements of the prenatal camel permanent or metanephric kidney. The primitive metanephros was first observed at the 13-mm crown vertebral rump length (CVRL) stage as an ovoid structure composed of a centrally located epithelial ureteric bud and peripheral circumscribed masses of undifferentiated mesenchymal cells. The first morphological evidence of glomerulogenesis was observed at the 28-mm CVRL stage. Developing renal corpuscles became obvious at the 35-mm CVRL stage. At the 60-mm CVRL stage, the epithelial renal pelvis gave rise to tubular branches that extended towards the cortical zone. These branches represented the presumptive collecting ducts. Differentiation of renal tubules into the proximal and distal convoluted tubules was observed at the 95-mm CVRL stage. At the 130-mm CVRL stage, the renal medulla was clearly delineated into medullary pyramids, which in association with the corresponding cortical caps formed the morphological basis of the renal lobar formation. A gradual nephrogenic decline was noticed from the 940-mm CVRL on; however, the process of nephrogenesis persisted throughout all the studied foetal stages. © 2013 Blackwell Verlag GmbH.

Structural Mechanics and Dynamics Branch

NASA Technical Reports Server (NTRS)

Stefko, George

2003-01-01

The 2002 annual report of the Structural Mechanics and Dynamics Branch reflects the majority of the work performed by the branch staff during the 2002 calendar year. Its purpose is to give a brief review of the branch s technical accomplishments. The Structural Mechanics and Dynamics Branch develops innovative computational tools, benchmark experimental data, and solutions to long-term barrier problems in the areas of propulsion aeroelasticity, active and passive damping, engine vibration control, rotor dynamics, magnetic suspension, structural mechanics, probabilistics, smart structures, engine system dynamics, and engine containment. Furthermore, the branch is developing a compact, nonpolluting, bearingless electric machine with electric power supplied by fuel cells for future "more electric" aircraft. An ultra-high-power-density machine that can generate projected power densities of 50 hp/lb or more, in comparison to conventional electric machines, which generate usually 0.2 hp/lb, is under development for application to electric drives for propulsive fans or propellers. In the future, propulsion and power systems will need to be lighter, to operate at higher temperatures, and to be more reliable in order to achieve higher performance and economic viability. The Structural Mechanics and Dynamics Branch is working to achieve these complex, challenging goals.

Intimal cushions and endothelial nuclear elongation around mouse aortic branches and their spatial correspondence with patterns of lipid deposition

PubMed Central

Bond, Andrew R.; Ni, Chih-Wen; Jo, Hanjoong

2010-01-01

Spatial variation in hemodynamic stresses acting on the arterial wall may explain the nonuniform distribution of atherosclerosis. In thoracic aortas of LDL receptor/apolipoprotein E double knockout mice, lesions develop preferentially around the entire circumference of intercostal branch ostia, regardless of age, with the highest prevalence occurring upstream. Additional chevron-shaped lesions occur further upstream of the ostia. This pattern differs from the age-related ones occurring in people and rabbits. In the present study, patterns of near-wall blood flow around intercostal ostia in wild-type mice were estimated from the morphology of endothelial nuclei, which were shown in vitro to elongate in response to elevated shear stress and to align with the flow, and wall structure was assessed from confocal and scanning electron microscopy. A triangular intimal cushion surrounded the upstream part of most ostia. Nuclear length-to-width ratios were lowest over this cushion and highest at the sides of branches, regardless of age. Nuclear orientations were consistent with flow diverging around the branch. The pattern of nuclear morphology differed from the age-related ones observed in rabbits. The intimal cushion and the distribution of shear stress inferred from these observations can partly account for the pattern of lesions observed in knockout mice. Nuclear elongation in nonbranch regions was approximately constant across animals of different size, demonstrating the existence of a mechanism by which endothelial cells compensate for the dependence of mean aortic wall shear stress on body mass. PMID:19933414

Dragging a floating horizontal cylinder

NASA Astrophysics Data System (ADS)

Lee, Duck-Gyu; Kim, Ho-Young

2010-11-01

A cylinder immersed in a fluid stream experiences a drag, and it is well known that the drag coefficient is a function of the Reynolds number only. Here we study the force exerted on a long horizontal cylinder that is dragged perpendicular to its axis while floating on an air-water interface with a high Reynolds number. In addition to the flow-induced drag, the floating body is subjected to capillary forces along the contact line where the three phases of liquid/solid/gas meet. We first theoretically predict the meniscus profile around the horizontally moving cylinder assuming the potential flow, and show that the profile is in good agreement with that obtained experimentally. Then we compare our theoretical predictions and experimental measurement results for the drag coefficient of a floating horizontal cylinder that is given by a function of the Weber number and the Bond number. This study can help us to understand the horizontal motion of partially submerged objects at air-liquid interface, such as semi-aquatic insects and marine plants.

Changes in scleractinian coral Seriatopora hystrix morphology and its endocellular Symbiodinium characteristics along a bathymetric gradient from shallow to mesophotic reef

NASA Astrophysics Data System (ADS)

Nir, O.; Gruber, D. F.; Einbinder, S.; Kark, S.; Tchernov, D.

2011-12-01

The algae living endosymbiotically within coral are thought to increase algal pigmentation with increasing depth to capture the diminishing light. Here, we follow distribution of the hermatypic coral Seriatopora hystrix along a 60-m bathymetric gradient in the Gulf of Eilat, Red Sea, to study coral ecophysiology and response to light regimes. Combining work on coral morphology, pigment content and genotyping of the photosymbiont, we found that total chlorophyll concentration per zooxanthellae cell and the dark- and light-acclimated quantum yield of photosystem II did not vary significantly along the 60-m gradient. However, the chlorophyll a/c ratio increased with depth. This suggests that the symbiotic algae in S. hystrix possess a mechanism for acclimatization or adaptation that differs from previously described pathways. The accepted photoacclimatory process involves an increase in chlorophyll content per alga as light intensity decreases. Based on corallite and branch morphology, this research suggests that S. hystrix has two depth-dependent ecophenotypes. Above 10 m depth, S. hystrix exhibits sturdier colony configurations with thick branches, while below 30 m depth, colonies are characterized by thin branches and the presence of a larger polyp area. Between 10 and 30 m depth, both ecophenotypes are present, suggesting that corallite morphology may act as another axis of photoacclimation with depth.

Structural dynamics branch research and accomplishments

NASA Technical Reports Server (NTRS)

1990-01-01

Summaries are presented of fiscal year 1989 research highlights from the Structural Dynamics Branch at NASA Lewis Research Center. Highlights from the branch's major work areas include aeroelasticity, vibration control, dynamic systems, and computation structural methods. A listing of the fiscal year 1989 branch publications is given.

Research program of the Geodynamics Branch

NASA Technical Reports Server (NTRS)

Kahn, W. D. (Editor); Cohen, S. C. (Editor); Boccucci, B. S. (Editor)

1986-01-01

This report is the Fourth Annual Summary of the Research Program of the Geodynamics Branch. The branch is located within the Laboratory for Terrestrial Physics of the Space and Earth Sciences Directorate of the Goddard Space Flight Center. The research activities of the branch staff cover a broad spectrum of geoscience disciplines including: tectonophysics, space geodesy, geopotential field modeling, and dynamic oceanography. The NASA programs which are supported by the work described in this document include the Geodynamics and Ocean Programs, the Crustal Dynamics Project and the proposed Ocean Topography Experiment (TOPEX). The reports highlight the investigations conducted by the Geodynamics Branch staff during calendar year 1985. The individual papers are grouped into chapters on Crustal Movements and Solid Earth Dynamics, Gravity Field Modeling and Sensing Techniques, and Sea Surface Topography. Further information on the activities of the branch or the particular research efforts described herein can be obtained through the branch office or from individual staff members.

[Branches of the National Institute of Hygiene].

PubMed

Gromulska, Marta

2008-01-01

National Epidemiological Institute (National Institute of Hygiene, from 7th September 1923) was established in 1918 in Warsaw and acted at national level. Its actions in the field of diseases combat were supported by bacteriological stations and vaccine production in voivodeship cities, which were taken charge of by the state, and names "National Epidemiological Institutes". According to the ministers resolution from 6th July 1921,Epidemiological Institutes were merged to National Central Epidemiological Institutes (PZH), the epidemiological institutes outside Warsaw were named branches, which were to be located in every voivodeship city, according to the initial organizational resolutions. There were country branches of NCEI in: Cracow, Lwów, Lódź, Toruń, Lublin, and Wilno in the period 1919-1923. New branches in Poznań (1925), Gdynia(1934), Katowice (Voivodeship Institute of Hygiene (1936), Luck (1937), Stanisławów (1937), Kielce(1938), and Brześć/Bug (Municipal Station acting as branch of National Central Epidemiological Institute. Branches were subordinated to NCEI-PZH) in Warsaw where action plans and unified research and diagnostic method were established and annual meeting of the country branches managers took place. All branches cooperated with hospitals, national health services, district general practitioners and administration structure in control of infectious diseases. In 1938, the post of branch inspector was established, the first of whom was Feliks Przesmycki PhD. Branches cooperated also with University of Cracow, University of Lwów and University of Wilno. In 1935, National Institutes of Food Research was incorporated in PZH, Water Department was established, and these areas of activity began to develop in the branches accordingly. In 1938 there were 13 branches of PZH, and each had three divisions: bacteriological, food research and water research. Three branches in Cracow, Kielce and Lublin worked during World War II under German

Full-scale testing and early production results from horizontal air sparging and soil vapor extraction wells remediating jet fuel in soil and groundwater at JFK International Airport, New York

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roth, R.J.; Bianco, P.; Kirshner, M.

1996-12-31

Jet fuel contaminated soil and groundwater contaminated at the International Arrivals Building (IAB) of the JFK International Airport in Jamaica, New York, are being remediated using soil vapor extraction (SVE) and air sparging (AS). The areal extent of the contaminated soil is estimated to be 70 acres and the volume of contaminated groundwater is estimated to be 2.3 million gallons. The remediation uses approximately 13,000 feet of horizontal SVE (HSVE) wells and 7,000 feet of horizontal AS (HAS) wells. The design of the HSVE and HAS wells was based on a pilot study followed by a full-scale test. In additionmore » to the horizontal wells, 28 vertical AS wells and 15 vertical SVE wells are used. Three areas are being remediated, thus, three separate treatment systems have been installed. The SVE and AS wells are operated continuously while groundwater will be intermittently extracted at each HAS well, treated by liquid phase activated carbon and discharged into stormwater collection sewerage. Vapors extracted by the SVE wells are treated by vapor phase activated carbon and discharged into ambient air. The duration of the remediation is anticipated to be between two and three years before soil and groundwater are remediated to New York State cleanup criteria for the site. Based on the monitoring data for the first two months of operation, approximately 14,600 lbs. of vapor phase VOCs have been extracted. Analyses show that the majority of the VOCs are branched alkanes, branched alkenes, cyclohexane and methylated cyclohexanes.« less

30 CFR 56.6403 - Branch circuits.

Code of Federal Regulations, 2010 CFR

2010-07-01

... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Electric Blasting § 56.6403 Branch circuits. (a) If electric blasting includes the use of branch circuits, each... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Branch circuits. 56.6403 Section 56.6403...

17 CFR 166.4 - Branch offices.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Branch offices. 166.4 Section 166.4 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION CUSTOMER PROTECTION RULES § 166.4 Branch offices. Each branch office of each Commission registrant must use the name of the...

Branch Input Resistance and Steady Attenuation for Input to One Branch of a Dendritic Neuron Model

PubMed Central

Rall, Wilfrid; Rinzel, John

1973-01-01

Mathematical solutions and numerical illustrations are presented for the steady-state distribution of membrane potential in an extensively branched neuron model, when steady electric current is injected into only one dendritic branch. Explicit expressions are obtained for input resistance at the branch input site and for voltage attenuation from the input site to the soma; expressions for AC steady-state input impedance and attenuation are also presented. The theoretical model assumes passive membrane properties and the equivalent cylinder constraint on branch diameters. Numerical examples illustrate how branch input resistance and steady attenuation depend upon the following: the number of dendritic trees, the orders of dendritic branching, the electrotonic length of the dendritic trees, the location of the dendritic input site, and the input resistance at the soma. The application to cat spinal motoneurons, and to other neuron types, is discussed. The effect of a large dendritic input resistance upon the amount of local membrane depolarization at the synaptic site, and upon the amount of depolarization reaching the soma, is illustrated and discussed; simple proportionality with input resistance does not hold, in general. Also, branch input resistance is shown to exceed the input resistance at the soma by an amount that is always less than the sum of core resistances along the path from the input site to the soma. PMID:4715583

Damage Tolerance Assessment Branch

NASA Technical Reports Server (NTRS)

Walker, James L.

2013-01-01

The Damage Tolerance Assessment Branch evaluates the ability of a structure to perform reliably throughout its service life in the presence of a defect, crack, or other form of damage. Such assessment is fundamental to the use of structural materials and requires an integral blend of materials engineering, fracture testing and analysis, and nondestructive evaluation. The vision of the Branch is to increase the safety of manned space flight by improving the fracture control and the associated nondestructive evaluation processes through development and application of standards, guidelines, advanced test and analytical methods. The Branch also strives to assist and solve non-aerospace related NDE and damage tolerance problems, providing consultation, prototyping and inspection services.

[Vestibular compensation studies]. [Vestibular Compensation and Morphological Studies

NASA Technical Reports Server (NTRS)

Perachio, Adrian A. (Principal Investigator)

1996-01-01

The following topics are reported: neurophysiological studies on MVN neurons during vestibular compensation; effects of spinal cord lesions on VNC neurons during compensation; a closed-loop vestibular compensation model for horizontally canal-related MVN neurons; spatiotemporal convergence in VNC neurons; contributions of irregularly firing vestibular afferents to linear and angular VOR's; application to flight studies; metabolic measures in vestibular neurons; immediate early gene expression following vestibular stimulation; morphological studies on primary afferents, central vestibular pathways, vestibular efferent projection to the vestibular end organs, and three-dimensional morphometry and imaging.

High-yield aqueous synthesis of multi-branched iron oxide core-gold shell nanoparticles: SERS substrate for immobilization and magnetic separation of bacteria

NASA Astrophysics Data System (ADS)

Tamer, Ugur; Onay, Aykut; Ciftci, Hakan; Bozkurt, Akif Göktuğ; Cetin, Demet; Suludere, Zekiye; Hakkı Boyacı, İsmail; Daniel, Philippe; Lagarde, Fabienne; Yaacoub, Nader; Greneche, Jean-Marc

2014-10-01

The high product yield of multi-branched core-shell Fe3- x O4@Au magnetic nanoparticles was synthesized used as magnetic separation platform and surface-enhanced Raman scattering (SERS) substrates. The multi-branched magnetic nanoparticles were prepared by a seed-mediated growth approach using magnetic gold nanospheres as the seeds and subsequent reduction of metal salt with ascorbic acid in the presence of a stabilizing agent chitosan biopolymer and silver ions. The anisotropic growth of nanoparticles was observed in the presence of chitosan polymer matrix resulting in multi-branched nanoparticles with a diameter over 100 nm, and silver ions also play a crucial role on the growth of multi-branched nanoparticles. We propose the mechanism of the formation of multi-branched nanoparticles while the properties of nanoparticles embedded in chitosan matrix are discussed. The surface morphology of nanoparticles was characterized with transmission electron microscopy, scanning electron microscopy, ultraviolet visible spectroscopy (UV-Vis), X-ray diffraction, and fourier transform infrared spectroscopy and 57Fe Mössbauer spectrometry. Additionally, the magnetic properties of the nanoparticles were also examined. We also demonstrated that the synthesized Fe3- x O4@Au multi-branched nanoparticle is capable of targeted separation of pathogens from matrix and sensing as SERS substrates.

39 CFR 241.2 - Stations and branches.

Code of Federal Regulations, 2012 CFR

2012-07-01

... number, letter or name. As a general rule, branches are named. (2) Stations and branches transact... 39 Postal Service 1 2012-07-01 2012-07-01 false Stations and branches. 241.2 Section 241.2 Postal... DISCONTINUANCE § 241.2 Stations and branches. (a) Description. (1) Stations are established within the corporate...

39 CFR 241.2 - Stations and branches.

Code of Federal Regulations, 2013 CFR

2013-07-01

... number, letter or name. As a general rule, branches are named. (2) Stations and branches transact... 39 Postal Service 1 2013-07-01 2013-07-01 false Stations and branches. 241.2 Section 241.2 Postal... DISCONTINUANCE § 241.2 Stations and branches. (a) Description. (1) Stations are established within the corporate...

39 CFR 241.2 - Stations and branches.

Code of Federal Regulations, 2014 CFR

2014-07-01

... number, letter or name. As a general rule, branches are named. (2) Stations and branches transact... 39 Postal Service 1 2014-07-01 2014-07-01 false Stations and branches. 241.2 Section 241.2 Postal... DISCONTINUANCE § 241.2 Stations and branches. (a) Description. (1) Stations are established within the corporate...

39 CFR 241.2 - Stations and branches.

Code of Federal Regulations, 2011 CFR

2011-07-01

... number, letter or name. As a general rule, branches are named. (2) Stations and branches transact... 39 Postal Service 1 2011-07-01 2011-07-01 false Stations and branches. 241.2 Section 241.2 Postal... DISCONTINUANCE § 241.2 Stations and branches. (a) Description. (1) Stations are established within the corporate...

39 CFR 241.2 - Stations and branches.

Code of Federal Regulations, 2010 CFR

2010-07-01

... number, letter or name. As a general rule, branches are named. (2) Stations and branches transact... 39 Postal Service 1 2010-07-01 2010-07-01 false Stations and branches. 241.2 Section 241.2 Postal... DISCONTINUANCE § 241.2 Stations and branches. (a) Description. (1) Stations are established within the corporate...

Starch Granule Re-Structuring by Starch Branching Enzyme and Glucan Water Dikinase Modulation Affects Caryopsis Physiology and Metabolism

PubMed Central

Shaik, Shahnoor S.; Obata, Toshihiro; Hebelstrup, Kim H.; Schwahn, Kevin; Fernie, Alisdair R.; Mateiu, Ramona V.; Blennow, Andreas

2016-01-01

Starch is of fundamental importance for plant development and reproduction and its optimized molecular assembly is potentially necessary for correct starch metabolism. Re-structuring of starch granules in-planta can therefore potentially affect plant metabolism. Modulation of granule micro-structure was achieved by decreasing starch branching and increasing starch-bound phosphate content in the barley caryopsis starch by RNAi suppression of all three Starch Branching Enzyme (SBE) isoforms or overexpression of potato Glucan Water Dikinase (GWD). The resulting lines displayed Amylose-Only (AO) and Hyper-Phosphorylated (HP) starch chemotypes, respectively. We studied the influence of these alterations on primary metabolism, grain composition, starch structural features and starch granule morphology over caryopsis development at 10, 20 and 30 days after pollination (DAP) and at grain maturity. While HP showed relatively little effect, AO showed significant reduction in starch accumulation with re-direction to protein and β-glucan (BG) accumulation. Metabolite profiling indicated significantly higher sugar accumulation in AO, with re-partitioning of carbon to accumulate amino acids, and interestingly it also had high levels of some important stress-related metabolites and potentially protective metabolites, possibly to elude deleterious effects. Investigations on starch molecular structure revealed significant increase in starch phosphate and amylose content in HP and AO respectively with obvious differences in starch granule morphology at maturity. The results demonstrate that decreasing the storage starch branching resulted in metabolic adjustments and re-directions, tuning to evade deleterious effects on caryopsis physiology and plant performance while only little effect was evident by increasing starch-bound phosphate as a result of overexpressing GWD. PMID:26891365

Crossing safety barriers: influence of children's morphological and functional variables.

PubMed

Cordovil, Rita; Vieira, Filomena; Barreiros, João

2012-05-01

Thirty-three children between 3 and 6 years of age were asked to climb four different types of safety barriers. Morphological and functional variables of the children, which were expected to influence climbing or passing through skills, were collected. The influence of those variables on children's success rate and time to cross was tested. No barrier offered a total restraining efficacy. The horizontal bars barrier was crossed by 97% of the children. In the group of children that succeeded in crossing the four barriers, mean time to cross the most difficult barrier was 15 s. Age was the best predictor for success in crossing most barriers but morphology and strength were important predictors of time to cross. The influence of anthropometric variables in time to cross was dependent upon the characteristics of the barrier. A good design of safety barriers should consider children's age, morphology and strength. Copyright © 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved.

7 CFR 51.578 - Branch.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., CERTIFICATION, AND STANDARDS) United States Standards for Celery Definitions § 51.578 Branch. Branch means the leaf of a stalk and consists of the edible stem-like portion and the tops or leaf blades. ...

7 CFR 51.578 - Branch.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., CERTIFICATION, AND STANDARDS) United States Standards for Celery Definitions § 51.578 Branch. Branch means the leaf of a stalk and consists of the edible stem-like portion and the tops or leaf blades. ...

Controllable morphology of flux avalanches in microstructured superconductors

NASA Astrophysics Data System (ADS)

Motta, M.; Colauto, F.; Vestgârden, J. I.; Fritzsche, J.; Timmermans, M.; Cuppens, J.; Attanasio, C.; Cirillo, C.; Moshchalkov, V. V.; Van de Vondel, J.; Johansen, T. H.; Ortiz, W. A.; Silhanek, A. V.

2014-04-01

The morphology of abrupt bursts of magnetic flux into superconducting films with engineered periodic pinning centers (antidots) has been investigated. Guided flux avalanches of thermomagnetic origin develop a treelike structure, with the main trunk perpendicular to the borders of the sample, while secondary branches follow well-defined directions determined by the geometrical details of the underlying periodic pinning landscape. Strikingly, we demonstrate that in a superconductor with relatively weak random pinning the morphology of such flux avalanches can be fully controlled by proper combinations of lattice symmetry and antidot geometry. Moreover, the resulting flux patterns can be reproduced, to the finest details, by simulations based on a phenomenological thermomagnetic model. In turn, this model can be used to predict such complex structures and to estimate physical variables of more difficult experimental access, such as the local values of temperature and electric field.

12 CFR 545.92 - Branch offices.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Branch offices. 545.92 Section 545.92 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY FEDERAL SAVINGS ASSOCIATIONS-OPERATIONS § 545.92 Branch offices. (a) Definition. A branch office of a Federal savings association (“you”) is any...

Dendritic branching angles of pyramidal cells across layers of the juvenile rat somatosensory cortex.

PubMed

Leguey, Ignacio; Bielza, Concha; Larrañaga, Pedro; Kastanauskaite, Asta; Rojo, Concepción; Benavides-Piccione, Ruth; DeFelipe, Javier

2016-09-01

The characterization of the structural design of cortical microcircuits is essential for understanding how they contribute to function in both health and disease. Since pyramidal neurons represent the most abundant neuronal type and their dendritic spines constitute the major postsynaptic elements of cortical excitatory synapses, our understanding of the synaptic organization of the neocortex largely depends on the available knowledge regarding the structure of pyramidal cells. Previous studies have identified several apparently common rules in dendritic geometry. We study the dendritic branching angles of pyramidal cells across layers to further shed light on the principles that determine the geometric shapes of these cells. We find that the dendritic branching angles of pyramidal cells from layers II-VI of the juvenile rat somatosensory cortex suggest common design principles, despite the particular morphological and functional features that are characteristic of pyramidal cells in each cortical layer. J. Comp. Neurol. 524:2567-2576, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Horizontal fields generated by return strokes

NASA Technical Reports Server (NTRS)

Cooray, Vernon

1991-01-01

Horizontal fields generated by return strokes play an important role in the interaction of lightning generated electric fields with power lines. In many of the recent investigations on the interaction of lightning electromagnetic fields with power lines, the horizontal field was calculated by employing the expression for the tilt of the electric field of a plane wave propagating over finitely conducting earth. The method is suitable for calculating horizontal fields generated by return strokes at distances as close as 200m. At these close ranges, the use of the wavetilt expression can cause large errors.

ComM is a hexameric helicase that promotes branch migration during natural transformation in diverse Gram-negative species.

PubMed

Nero, Thomas M; Dalia, Triana N; Wang, Joseph Che-Yen; Kysela, David T; Bochman, Matthew L; Dalia, Ankur B

2018-05-02

Acquisition of foreign DNA by natural transformation is an important mechanism of adaptation and evolution in diverse microbial species. Here, we characterize the mechanism of ComM, a broadly conserved AAA+ protein previously implicated in homologous recombination of transforming DNA (tDNA) in naturally competent Gram-negative bacterial species. In vivo, we found that ComM was required for efficient comigration of linked genetic markers in Vibrio cholerae and Acinetobacter baylyi, which is consistent with a role in branch migration. Also, ComM was particularly important for integration of tDNA with increased sequence heterology, suggesting that its activity promotes the acquisition of novel DNA sequences. In vitro, we showed that purified ComM binds ssDNA, oligomerizes into a hexameric ring, and has bidirectional helicase and branch migration activity. Based on these data, we propose a model for tDNA integration during natural transformation. This study provides mechanistic insight into the enigmatic steps involved in tDNA integration and uncovers the function of a protein required for this conserved mechanism of horizontal gene transfer.

Directed branch growth in aligned nanowire arrays.

PubMed

Beaudry, Allan L; LaForge, Joshua M; Tucker, Ryan T; Sorge, Jason B; Adamski, Nicholas L; Li, Peng; Taschuk, Michael T; Brett, Michael J

2014-01-01

Branch growth is directed along two, three, or four in-plane directions in vertically aligned nanowire arrays using vapor-liquid-solid glancing angle deposition (VLS-GLAD) flux engineering. In this work, a dynamically controlled collimated vapor flux guides branch placement during the self-catalyzed epitaxial growth of branched indium tin oxide nanowire arrays. The flux is positioned to grow branches on select nanowire facets, enabling fabrication of aligned nanotree arrays with L-, T-, or X-branching. In addition, a flux motion algorithm is designed to selectively elongate branches along one in-plane axis. Nanotrees are found to be aligned across large areas by X-ray diffraction pole figure analysis and through branch length and orientation measurements collected over 140 μm(2) from scanning electron microscopy images for each array. The pathway to guided assembly of nanowire architectures with controlled interconnectivity in three-dimensions using VLS-GLAD is discussed.

Turing mechanism underlying a branching model for lung morphogenesis.

PubMed

Xu, Hui; Sun, Mingzhu; Zhao, Xin

2017-01-01

The mammalian lung develops through branching morphogenesis. Two primary forms of branching, which occur in order, in the lung have been identified: tip bifurcation and side branching. However, the mechanisms of lung branching morphogenesis remain to be explored. In our previous study, a biological mechanism was presented for lung branching pattern formation through a branching model. Here, we provide a mathematical mechanism underlying the branching patterns. By decoupling the branching model, we demonstrated the existence of Turing instability. We performed Turing instability analysis to reveal the mathematical mechanism of the branching patterns. Our simulation results show that the Turing patterns underlying the branching patterns are spot patterns that exhibit high local morphogen concentration. The high local morphogen concentration induces the growth of branching. Furthermore, we found that the sparse spot patterns underlie the tip bifurcation patterns, while the dense spot patterns underlies the side branching patterns. The dispersion relation analysis shows that the Turing wavelength affects the branching structure. As the wavelength decreases, the spot patterns change from sparse to dense, the rate of tip bifurcation decreases and side branching eventually occurs instead. In the process of transformation, there may exists hybrid branching that mixes tip bifurcation and side branching. Since experimental studies have reported that branching mode switching from side branching to tip bifurcation in the lung is under genetic control, our simulation results suggest that genes control the switch of the branching mode by regulating the Turing wavelength. Our results provide a novel insight into and understanding of the formation of branching patterns in the lung and other biological systems.

Advanced endografting techniques: snorkels, chimneys, periscopes, fenestrations, and branched endografts.

PubMed

Kansagra, Kartik; Kang, Joseph; Taon, Matthew-Czar; Ganguli, Suvranu; Gandhi, Ripal; Vatakencherry, George; Lam, Cuong

2018-04-01

The anatomy of aortic aneurysms from the proximal neck to the access vessels may create technical challenges for endovascular repair. Upwards of 30% of patients with abdominal aortic aneurysms (AAA) have unsuitable proximal neck morphology for endovascular repair. Anatomies considered unsuitable for conventional infrarenal stent grafting include short or absent necks, angulated necks, conical necks, or large necks exceeding size availability for current stent grafts. A number of advanced endovascular techniques and devices have been developed to circumvent these challenges, each with unique advantages and disadvantages. These include snorkeling procedures such as chimneys, periscopes, and sandwich techniques; "homemade" or "back-table" fenestrated endografts as well as manufactured, customized fenestrated endografts; and more recently, physician modified branched devices. Furthermore, new devices in the pipeline under investigation, such as "off-the-shelf" fenestrated stent grafts, branched stent grafts, lower profile devices, and novel sealing designs, have the potential of solving many of the aforementioned problems. The treatment of aortic aneurysms continues to evolve, further expanding the population of patients that can be treated with an endovascular approach. As the technology grows so do the number of challenging aortic anatomies that endovascular specialists take on, further pushing the envelope in the arena of aortic repair.

High accuracy diffuse horizontal irradiance measurements without a shadowband

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schlemmer, J.A; Michalsky, J.J.

1995-12-31

The standard method for measuring diffuse horizontal irradiance uses a fixed shadowband to block direct solar radiation. This method requires a correction for the excess skylight blocked by the band, and this correction varies with sky conditions. Alternately, diffuse horizontal irradiance may be calculated from total horizontal and direct normal irradiance. This method is in error because of angular (cosine) response of the total horizontal pyranometer to direct beam irradiance. This paper describes an improved calculation of diffuse horizontal irradiance from total horizontal and direct normal irradiance using a predetermination of the angular response of the total horizontal pyranometer. Wemore » compare these diffuse horizontal irradiance calculations with measurements made with a shading-disk pyranometer that shields direct irradiance using a tracking disk. Results indicate significant improvement in most cases. Remaining disagreement most likely arises from undetected tracking errors and instrument leveling.« less

Expansion of the 'Reticulosphere': Diversity of Novel Branching and Network-forming Amoebae Helps to Define Variosea (Amoebozoa).

PubMed

Berney, Cédric; Geisen, Stefan; Van Wichelen, Jeroen; Nitsche, Frank; Vanormelingen, Pieter; Bonkowski, Michael; Bass, David

2015-05-01

Amoebae able to form cytoplasmic networks or displaying a multiply branching morphology remain very poorly studied. We sequenced the small-subunit ribosomal RNA gene of 15 new amoeboid isolates, 14 of which are branching or network-forming amoebae (BNFA). Phylogenetic analyses showed that these isolates all group within the poorly-known and weakly-defined class Variosea (Amoebozoa). They are resolved into six lineages corresponding to distinct new morphotypes; we describe them as new genera Angulamoeba (type species Angulamoeba microcystivorans n. gen., n. sp.; and A. fungorum n. sp.), Arboramoeba (type species Arboramoeba reticulata n. gen., n. sp.), Darbyshirella (type species Darbyshirella terrestris n. gen., n. sp.), Dictyamoeba (type species Dictyamoeba vorax n. gen., n. sp.), Heliamoeba (type species Heliamoeba mirabilis n. gen., n. sp.), and Ischnamoeba (type species Ischnamoeba montana n. gen., n. sp.). We also isolated and sequenced four additional variosean strains, one belonging to Flamella, one related to Telaepolella tubasferens, and two members of the cavosteliid protosteloid lineage. We identified a further 104 putative variosean environmental clone sequences in GenBank, comprising up to 14 lineages that may prove to represent additional novel morphotypes. We show that BNFA are phylogenetically widespread in Variosea and morphologically very variable, both within and between lineages. Copyright © 2015 Elsevier GmbH. All rights reserved.

The morphology and classification of α ganglion cells in the rat retinae: a fractal analysis study.

PubMed

Jelinek, Herbert F; Ristanović, Dušan; Milošević, Nebojša T

2011-09-30

Rat retinal ganglion cells have been proposed to consist of a varying number of subtypes. Dendritic morphology is an essential aspect of classification and a necessary step toward understanding structure-function relationships of retinal ganglion cells. This study aimed at using a heuristic classification procedure in combination with the box-counting analysis to classify the alpha ganglion cells in the rat retinae based on the dendritic branching pattern and to investigate morphological changes with retinal eccentricity. The cells could be divided into two groups: cells with simple dendritic pattern (box dimension lower than 1.390) and cells with complex dendritic pattern (box dimension higher than 1.390) according to their dendritic branching pattern complexity. Both were further divided into two subtypes due to the stratification within the inner plexiform layer. In the present study we have shown that the alpha rat RCGs can be classified further by their dendritic branching complexity and thus extend those of previous reports that fractal analysis can be successfully used in neuronal classification, particularly that the fractal dimension represents a robust and sensitive tool for the classification of retinal ganglion cells. A hypothesis of possible functional significance of our classification scheme is also discussed. Copyright © 2011 Elsevier B.V. All rights reserved.

Guide to the Seattle Archives Branch.

ERIC Educational Resources Information Center

Hobbs, Richard, Comp.

The guide presents an overview of the textual and microfilmed records located at the Seattle Branch of the National Archives of the United States. Established in 1969, the Seattle Archives Branch is one of 11 branches which preserve and make available for research those U.S. Government records of permanent value created and maintained by Federal…

The Effects of a Branch Campus

ERIC Educational Resources Information Center

Lien, Donald; Wang, Yaqin

2012-01-01

We examine the effects of a branch campus on the social welfare of the host country and the foreign university. Overall, we find that a branch campus increases both the domestic social welfare (measured by the aggregate student utility) and the tuition revenue of the foreign university. The effect of a branch campus on the brain drain is…

Dynamic Crack Branching - A Photoelastic Evaluation,

DTIC Science & Technology

1982-05-01

0.41 mPai and a 0.18 MPa, and predicted a theoretical kinking angle of 84°whichagreed well with experimentally measured angle. After crack kinking...Consistent crack branching’at KIb = 2.04 MPaI -i- and r = 1.3 mm verified this crack branching criterion. The crack branching angle predicted by--.’ DD

Anatomical study of the internal nasal branch of the infraorbital nerve: Application to Minimizing Nerve Damage With Surgery In and Around the Nose.

PubMed

Iwanaga, Joe; Watanabe, Koichi; Henry, Brandon; Tomaszewski, Krzysztof A; Walocha, Jerzy A; Oskouian, Rod J; Tubbs, R Shane

2017-09-01

The internal nasal branch of the infraorbital nerve (ION) runs down the nose and around the ala to be distributed to the nasal septum and vestibule. The aim of this study was to measure the internal nasal branch around the ala of the nose and discuss its possible relevance in clinical/surgical practice. Twelve sides from seven specimens derived from fresh frozen and embalmed Caucasian cadaveric heads were dissected. The specimens included three males and four females. The ages of the cadavers at death ranged from 65 to 84 years. The diameter of the internal nasal branch, horizontal distance from the lateral contour of the ala (Point A) to the branch (distance H) and vertical distance from the bottom part of the ala (Point B) to the branch (distance V) were recorded. Distance H ranged from -1.6 to 1.5 mm on right sides and -1.0 to 1.5 mm on left sides. The diameter of the nerves at Point A ranged from 1.3 to 1.8 mm on right sides and 1.3 to 1.6 mm on left sides. Distance V ranged from -1.5 to 1.0 mm on right sides and -2.3 to 1.1 mm on left sides. The diameter of the nerves at Point B ranged from 0.7 to 1.3 mm on right sides and 0.8 to 1.2 mm on left sides. The results of this study are the first to detail the topography of the internal nasal branch of the ION. Clin. Anat. 30:817-820, 2017. © 2017Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Modified parton branching model for multi-particle production in hadronic collisions: Application to SUSY particle branching

NASA Astrophysics Data System (ADS)

Yuanyuan, Zhang

The stochastic branching model of multi-particle productions in high energy collision has theoretical basis in perturbative QCD, and also successfully describes the experimental data for a wide energy range. However, over the years, little attention has been put on the branching model for supersymmetric (SUSY) particles. In this thesis, a stochastic branching model has been built to describe the pure supersymmetric particle jets evolution. This model is a modified two-phase stochastic branching process, or more precisely a two phase Simple Birth Process plus Poisson Process. The general case that the jets contain both ordinary particle jets and supersymmetric particle jets has also been investigated. We get the multiplicity distribution of the general case, which contains a Hypergeometric function in its expression. We apply this new multiplicity distribution to the current experimental data of pp collision at center of mass energy √s = 0.9, 2.36, 7 TeV. The fitting shows the supersymmetric particles haven't participate branching at current collision energy.

Branching out in locomotion: the mechanics of perch use in birds and primates.

PubMed

Bonser, R H

1999-06-01

Many animals use thin perches, such as the branches of trees, as locomotory substrates. In this paper, I have reviewed the literature concerned with measurements of locomotory forces made by birds and primates on thin and flexible substrates. Through a knowledge of the locomotory forces exerted by animals when using different substrates, the mechanical cost of their use can be established. We are just beginning to learn about the magnitude and patterns of force production in various branch-using vertebrates, primarily as a result of the development of instrumented perches. Instrumented perches have been designed to measure the forces produced by birds and primates when leaping from rigid and flexible horizontal and flexible vertical perches, and also from instrumented handgrips during brachiation. The development of these techniques for birds and primates allows us to compare the way in which they use perches as locomotory substrates. In both birds and primates, the magnitudes of landing forces are smaller than those during take-off. Two explanations have been proposed; the difference is either a consequence of perch compliance or it is a strategic decision to be cautious of 'new' perches. Leaps from flexible perches may be somewhat inefficient because considerable energy is dissipated in bending the perch, and this energy may remain unrecovered when the animal leaves contact with the perch.

New branched DNA constructs.

PubMed

Chandra, Madhavaiah; Keller, Sascha; Gloeckner, Christian; Bornemann, Benjamin; Marx, Andreas

2007-01-01

The Watson-Crick base pairing of DNA is an advantageous phenomenon that can be exploited when using DNA as a scaffold for directed self-organization of nanometer-sized objects. Several reports have appeared in the literature that describe the generation of branched DNA (bDNA) with variable numbers of arms that self-assembles into predesigned architectures. These bDNA units are generated by using cleverly designed rigid crossover DNA molecules. Alternatively, bDNA can be generated by using synthetic branch points derived from either nucleoside or non-nucleoside building blocks. Branched DNA has scarcely been explored for use in nanotechnology or from self-assembling perspectives. Herein, we wish to report our results for the synthesis, characterization, and assembling properties of asymmetrical bDNA molecules that are able to generate linear and circular bDNA constructs. Our strategy for the generation of bDNA is based on a branching point that makes use of a novel protecting-group strategy. The bDNA units were generated by means of automated DNA synthesis methods and were used to generate novel objects by employing chemical and biological techniques. The entities generated might be useful building blocks for DNA-based nanobiotechnology.

High accuracy diffuse horizontal irradiance measurements without a shadowband

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schlemmer, J.A.; Michalsky, J.J.

1995-10-01

The standard method for measuring diffuse horizontal irradiance uses a fixed shadowband to block direct solar radiation. This method requires a correction for the excess skylight blocked by the band, and this correction varies with sky conditions. Alternately, diffuse horizontal irradiance may be calculated from the total horizontal and direct normal irradiance. This method is in error because of the angular (often referred to as cosine) response of the total horizontal pyranometer to direct beam irradiance. This paper describes an improved calculation of diffuse horizontal irradiance from total horizontal and direct normal irradiance using a predetermination of the angular responsemore » of the total horizontal pyranometer. The authors compare these diffuse horizontal irradiance calculations with measurements made with a shading-disk pyranometer that shields direct irradiance using a tracking disk. The results indicate significant improvement in most cases. The remaining disagreement most likely arises from undetected tracking errors and instrument leveling.« less

Reshaping Plant Biology: Qualitative and Quantitative Descriptors for Plant Morphology

PubMed Central

Balduzzi, Mathilde; Binder, Brad M.; Bucksch, Alexander; Chang, Cynthia; Hong, Lilan; Iyer-Pascuzzi, Anjali S.; Pradal, Christophe; Sparks, Erin E.

2017-01-01

An emerging challenge in plant biology is to develop qualitative and quantitative measures to describe the appearance of plants through the integration of mathematics and biology. A major hurdle in developing these metrics is finding common terminology across fields. In this review, we define approaches for analyzing plant geometry, topology, and shape, and provide examples for how these terms have been and can be applied to plants. In leaf morphological quantifications both geometry and shape have been used to gain insight into leaf function and evolution. For the analysis of cell growth and expansion, we highlight the utility of geometric descriptors for understanding sepal and hypocotyl development. For branched structures, we describe how topology has been applied to quantify root system architecture to lend insight into root function. Lastly, we discuss the importance of using morphological descriptors in ecology to assess how communities interact, function, and respond within different environments. This review aims to provide a basic description of the mathematical principles underlying morphological quantifications. PMID:28217137

Form matters: morphological aspects of lateral root development

PubMed Central

Szymanowska-Pułka, Joanna

2013-01-01

Background The crucial role of roots in plant nutrition, and consequently in plant productivity, is a strong motivation to study the growth and functioning of various aspects of the root system. Numerous studies on lateral roots, as a major determinant of the root system architecture, mostly focus on the physiological and molecular bases of developmental processes. Unfortunately, little attention is paid either to the morphological changes accompanying the formation of a lateral root or to morphological defects occurring in lateral root primordia. The latter are observed in some mutants and occasionally in wild-type plants, but may also result from application of external factors. Scope and Conclusions In this review various morphological aspects of lateral branching in roots are analysed. Morphological events occurring during the formation of a typical lateral root are described. This process involves dramatic changes in the geometry of the developing organ that at early stages are associated with oblique cell divisions, leading to breaking of the symmetry of the cell pattern. Several types of defects in the morphology of primordia are indicated and described. Computer simulations show that some of these defects may result from an unstable field of growth rates. Significant changes in both primary and lateral root morphology may also be a consequence of various mutations, some of which are auxin-related. Examples reported in the literature are considered. Finally, lateral root formation is discussed in terms of mechanics. In this approach the primordium is considered as a physical object undergoing deformation and is characterized by specific mechanical properties. PMID:24190952

Sodium Channel β2 Subunits Prevent Action Potential Propagation Failures at Axonal Branch Points.

PubMed

Cho, In Ha; Panzera, Lauren C; Chin, Morven; Hoppa, Michael B

2017-09-27

Neurotransmitter release depends on voltage-gated Na + channels (Na v s) to propagate an action potential (AP) successfully from the axon hillock to a synaptic terminal. Unmyelinated sections of axon are very diverse structures encompassing branch points and numerous presynaptic terminals with undefined molecular partners of Na + channels. Using optical recordings of Ca 2+ and membrane voltage, we demonstrate here that Na + channel β2 subunits (Na v β2s) are required to prevent AP propagation failures across the axonal arborization of cultured rat hippocampal neurons (mixed male and female). When Na v β2 expression was reduced, we identified two specific phenotypes: (1) membrane excitability and AP-evoked Ca 2+ entry were impaired at synapses and (2) AP propagation was severely compromised with >40% of axonal branches no longer responding to AP-stimulation. We went on to show that a great deal of electrical signaling heterogeneity exists in AP waveforms across the axonal arborization independent of axon morphology. Therefore, Na v β2 is a critical regulator of axonal excitability and synaptic function in unmyelinated axons. SIGNIFICANCE STATEMENT Voltage-gated Ca 2+ channels are fulcrums of neurotransmission that convert electrical inputs into chemical outputs in the form of vesicle fusion at synaptic terminals. However, the role of the electrical signal, the presynaptic action potential (AP), in modulating synaptic transmission is less clear. What is the fidelity of a propagating AP waveform in the axon and what molecules shape it throughout the axonal arborization? Our work identifies several new features of AP propagation in unmyelinated axons: (1) branches of a single axonal arborization have variable AP waveforms independent of morphology, (2) Na + channel β2 subunits modulate AP-evoked Ca 2+ -influx, and (3) β2 subunits maintain successful AP propagation across the axonal arbor. These findings are relevant to understanding the flow of excitation in the

[Transverse radioulnar branch of the dorsal ulnar nerve: anatomic description and arthroscopic implications from 45 cadaveric dissections].

PubMed

Ehlinger, M; Rapp, E; Cognet, J-M; Clavert, P; Bonnomet, F; Kahn, J-L; Kempf, J-F

2005-05-01

We conducted an anatomic study of the transverse branch of the dorsal ulnar nerve to describe its morphology and position in relation to arthroscopic exploration portals. Forty-five non-side-matched anatomic specimens of unknown age and gender were preserved in formol. The dorsal branch of the ulnar nerve was identified and dissected proximally to distally in order to reveal the different terminal branches. The morphometric analysis included measurement of the length and diameter of the transverse branch and measurement of wrist width. We also measured the smallest distance between the transverse branch and the ulnar styloid process, and between the branch and usual arthroscopic portals (4-5, 6R, 6U) in the axis of the forearm. The transverse branch was inconstant. It was found in 12 of the 45 dissection specimens (27%). In two-thirds of the specimens, the branch ran over less than 50% of the wrist width, tangentially to the radiocarpal joint. Mean nerve diameter was 1 mm. It was found 5-6 mm from the ulnar styloid process and was distal to it in 83% of the specimens. The dissections demonstrated two anatomic variants. Type A corresponded to a branch running distally to the ulnar styloid process, parallel to the joint line (10/12 specimens). Type B exhibited a trajectory proximal to the ulnar styloid process, crossing the ulnar head (2/12 specimens). The relations with the arthroscopic portals (4-5, 6R, 6U) showed that the mean distance from the branch to the portal was 3.75 mm for the 4-5 portal (distally in 11/12 specimens), 3.68 mm for the 6R portal (distally in 10/12 specimens), and 4.83 mm for the 6U portal (distally in 7 specimens and proximally in 5). To our knowledge, there has been only one report specifically devoted to this transverse branch. Two other reports simply mention its existence. According to the literature, the transverse branch of the dorsal ulnar nerve occurs in 60-80% of the cases. We found two anatomic variations different than those

Cravity modulation of the moss Tortula modica branching

NASA Astrophysics Data System (ADS)

Khorkavtsiv, Yaroslava; Kit, Nadja

Among various abiotic factors the sensor system of plants constantly perceives light and gravitation impulses and reacts on their action by photo- and gravitropisms. Tropisms play fundamental part in ontogenesis and determination of plant forms. Essentially important question is how light initiating phototropic bending modulates gravitropism. In contrast to flower plants, red light is phototropically active for mosses, and phytochromic system controls initiation of apical growth, branching and photomorphogenesis of mosses. The aim of this investigation was to analyse cell branching of protonemata Tortula modica Zander depending on the direction of light and gravitation vector. The influence of light and gravitation on the form of protonemal turf T. modica, branching and the angle of lateral branches relative to axis of mother cell growth has been investigated. As moss protonemata is not branched in the darkness, light is necessary for branching activation. Minimally low intensity of the red light (0.2 mmol (.) m (-2) ({) .}sec (-1) ) induced branching without visual display of phototropic growth. It has been established that unidirectional action of light and gravitation intensifies branching, and, on the contrary, perpendicularly oriented vectors of factors weaken branches formation. Besides, parallel oriented vectors initiated branching from both cell sides, but oppositely directed vectors initiated branching only from one side. Clinostate rotation the change of the vector gravity and causes uniform cell branching, hence, light and gravitation mutually influence the branching system form of the protonemata cell. It has been shown that the angle of lateral branches in darkness does not depend on the direction of light and gravitation action. After lighting the local growth of the cell wall took place mainly under the angle 90 (o) to the axes of mother cell growth. Then the angle gradually decreased and in 3-4 cell divisions the lateral branch grew under the angle

Additional chain-branching pathways in the low-temperature oxidation of branched alkanes

DOE PAGES

Wang, Zhandong; Zhang, Lidong; Moshammer, Kai; ...

2015-12-31

Chain-branching reactions represent a general motif in chemistry, encountered in atmospheric chemistry, combustion, polymerization, and photochemistry; the nature and amount of radicals generated by chain-branching are decisive for the reaction progress, its energy signature, and the time towards its completion. In this study, experimental evidence for two new types of chain-branching reactions is presented, based upon detection of highly oxidized multifunctional molecules (HOM) formed during the gas-phase low-temperature oxidation of a branched alkane under conditions relevant to combustion. The oxidation of 2,5-dimethylhexane (DMH) in a jet-stirred reactor (JSR) was studied using synchrotron vacuum ultra-violet photoionization molecular beam mass spectrometry (SVUV-PI-MBMS).more » Specifically, species with four and five oxygen atoms were probed, having molecular formulas of C 8H 14O 4 (e.g., diketo-hydroperoxide/keto-hydroperoxy cyclic ether) and C 8H 16O 5 (e.g., keto-dihydroperoxide/dihydroperoxy cyclic ether), respectively. The formation of C 8H 16O 5 species involves alternative isomerization of OOQOOH radicals via intramolecular H-atom migration, followed by third O 2 addition, intramolecular isomerization, and OH release; C 8H 14O 4 species are proposed to result from subsequent reactions of C 8H 16O 5 species. The mechanistic pathways involving these species are related to those proposed as a source of low-volatility highly oxygenated species in Earth's troposphere. At the higher temperatures relevant to auto-ignition, they can result in a net increase of hydroxyl radical production, so these are additional radical chain-branching pathways for ignition. Furthermore, the results presented herein extend the conceptual basis of reaction mechanisms used to predict the reaction behavior of ignition, and have implications on atmospheric gas-phase chemistry and the oxidative stability of organic substances.« less

A comparison of pectoral fin ray morphology and its impact on fin ray flexural stiffness in labriform swimmers.

PubMed

Aiello, Brett R; Hardy, Adam R; Cherian, Chery; Olsen, Aaron M; Orsbon, Courtney P; Hale, Melina E; Westneat, Mark W

2018-04-25

The organization of tissues in appendages often affects their mechanical properties and function. In the fish family Labridae, swimming behavior is associated with pectoral fin flexural stiffness and morphology, where fins range on a continuum from stiff to relatively flexible fins. Across this diversity, pectoral fin flexural stiffness decreases exponentially along the length of any given fin ray, and ray stiffness decreases along the chord of the fin from the leading to trailing edge. In this study, we examine the morphological properties of fin rays, including the effective modulus in bending (E), second moment of area (I), segmentation, and branching patterns, and their impact on fin ray stiffness. We quantify intrinsic pectoral fin ray stiffness in similarly sized fins of two closely related species that employ fins of divergent mechanics, the flapping Gomphosus varius and the rowing Halichoeres bivittatus. While segmentation patterns and E were similar between species, measurements of I and the number of fin ray branch nodes were greater in G. varius than in H. bivittatus. A multiple regression model found that of these variables, I was always significantly correlated with fin ray flexural stiffness and that variation in I always explained the majority of the variation in flexural stiffness. Thus, while most of the morphological variables quantified in this study correlate with fin ray flexural stiffness, second moment of area is the greatest factor contributing to variation in flexural stiffness. Further, interspecific variation in fin ray branching pattern could be used as a means of tuning the effective stiffness of the fin webbing to differences in swimming behavior and hydrodynamics. The comparison of these results to other systems begins to unveil fundamental morphological features of biological beams and yields insight into the role of mechanical properties in fin deformation for aquatic locomotion. © 2018 Wiley Periodicals, Inc.

[Three-dimensional morphological modeling and visualization of wheat root system].

PubMed

Tan, Feng; Tang, Liang; Hu, Jun-Cheng; Jiang, Hai-Yan; Cao, Wei-Xing; Zhu, Yan

2011-01-01

Crop three-dimensional (3D) morphological modeling and visualization is an important part of digital plant study. This paper aimed to develop a 3D morphological model of wheat root system based on the parameters of wheat root morphological features, and to realize the visualization of wheat root growth. According to the framework of visualization technology for wheat root growth, a 3D visualization model of wheat root axis, including root axis growth model, branch geometric model, and root axis curve model, was developed firstly. Then, by integrating root topology, the corresponding pixel was determined, and the whole wheat root system was three-dimensionally re-constructed by using the morphological feature parameters in the root morphological model. Finally, based on the platform of OpenGL, and by integrating the technologies of texture mapping, lighting rendering, and collision detection, the 3D visualization of wheat root growth was realized. The 3D output of wheat root system from the model was vivid, which could realize the 3D root system visualization of different wheat cultivars under different water regimes and nitrogen application rates. This study could lay a technical foundation for further development of an integral visualization system of wheat plant.

nNOS-positive minor-branches of the dorsal penile nerves is associated with erectile function in the bilateral cavernous injury model of rats.

PubMed

Chen, Yen-Lin; Chao, Ting-Ting; Wu, Yi-No; Chen, Meng-Chuan; Lin, Ying-Hung; Liao, Chun-Hou; Wu, Chien-Chih; Chen, Kuo-Chiang; Chou, Shang-Shing P; Chiang, Han-Sun

2018-01-17

The changes in neuronal nitric oxide synthases (nNOS) in the dorsal penile nerves (DPNs) are consistent with cavernous nerve (CN) injury in rat models. However, the anatomical relationship and morphological changes between the minor branches of the DPNs and the CNs after injury have never been clearly explored. There were forty 12 week old male Sprague-Dawley rats receiving bilateral cavernous nerve injury (BCNI). Erectile function of intracavernous pressure and mean arterial pressure were measured. The histology and ultrastructure with H&E stain, Masson's trichrome stain and immunohistochemical stains were applied on the examination of CNs and DPNs. We demonstrated communicating nerve branches between the DPNs and the CNs in rats. The greatest damage and lowest erectile function were seen in the 14 th day and partially recovered in the 28 th day after BCNI. The nNOS positive DPN minor branches' number was significantly correlated with erectile function. The sub-analysis of the number of nNOS positive DPN minor branches also matched with the time course of the erectile function after BCNI. We suggest the regeneration of the DPNs minor branches would ameliorate the erectile function in BCNI rats.

Color and Morphology of Lava Flows on Io

NASA Astrophysics Data System (ADS)

Piatek, Jennifer L.; McElfresh, Sarah B. Z.; Byrnes, Jeffrey M.; Hale, Amy Snyder; Crown, David A.

2000-12-01

Analyses of color and morphologic changes in Voyager images of lava flows on Io were conducted to extend previous flow studies to additional volcanoes in preparation for comparison to Galileo data. Blue and orange filter images of Atar, Daedalus, and Ra Paterae were examined to identify systematic downflow decreases in blue/orange reflectivity suggested in earlier studies as diagnostic of color changes in cooled sulfur flows. Analyses of the color and morphology of 21 lava flows were conducted at these volcanoes, with additional morphologic analysis of lava flows at Agni, Masaaw, Mbali, Shoshu, and Talos Paterae. A total of 66 lava flows of up to 245 km in length were mapped to identify morphologic changes consistent with the rheologic changes expected to occur in sulfur flows. Although downflow color changes are observed, the trends are not consistent, even at the same edifice. Individual flows exhibit a statistically significant increase in blue/orange ratio, decrease in blue/orange ratio, or a lack of progressive downflow color variation. Color changes have similar magnitudes downflow and across flow, and the color ranges observed are similar from volcano to volcano, suggesting that similar processes are controlling color ratios at these edifices. In addition, using flow widening and branching as an indicator of the low viscosity exhibited by sulfur cooling from high temperatures, these flows do not exhibit morphologic changes consistent with the systematic behavior expected from the simple progressive cooling of sulfur.

Branch Width and Height Influence the Incorporation of Branches into Foraging Trails and Travel Speed in Leafcutter Ants Atta cephalotes (L.) (Hymenoptera: Formicidae).

PubMed

Freeman, B M; Chaves-Campos, J

2016-06-01

Fallen branches are often incorporated into Atta cephalotes (L.) foraging trails to optimize leaf tissue transport rates and economize trail maintenance. Recent studies in lowlands show laden A. cephalotes travel faster across fallen branches than on ground, but more slowly ascending or descending a branch. The latter is likely because (1) it is difficult to travel up or downhill and (2) bottlenecks occur when branches are narrower than preceding trail. Hence, both branch height and width should determine whether branches decrease net travel times, but no study has evaluated it yet. Laden A. cephalotes were timed in relation to branch width and height across segments preceding, accessing, across, and departing a fallen branch in the highlands of Costa Rica. Ants traveled faster on branches than on cleared segments of trunk-trail, but accelerated when ascending or descending the branch-likely because of the absence of bottlenecks during the day in the highlands. Branch size did not affect ant speed in observed branches; the majority of which (22/24) varied from 11 to 120 mm in both height and width (average 66 mm in both cases). To determine whether ants exclude branches outside this range, ants were offered the choice between branches within this range and branches that were taller/wider than 120 mm. Ants strongly preferred the former. Our results indicate that A. cephalotes can adjust their speed to compensate for the difficulty of traveling on branch slopes. More generally, branch size should be considered when studying ant foraging efficiency.

Characterizing local variability in long‐period horizontal tilt noise

USGS Publications Warehouse

Rohde, M.D.; Ringler, Adam; Hutt, Charles R.; Wilson, David; Holland, Austin; Sandoval, L.D; Storm, Tyler

2017-01-01

Horizontal seismic data are dominated by atmospherically induced tilt noise at long periods (i.e., 30 s and greater). Tilt noise limits our ability to use horizontal data for sensitive seismological studies such as observing free earth modes. To better understand the local spatial variability of long‐period horizontal noise, we observe horizontal noise during quiet time periods in the Albuquerque Seismological Laboratory (ASL) underground vault using four small‐aperture array configurations. Each array comprises eight Streckeisen STS‐2 broadband seismometers. We analyze the spectral content of the data using power spectral density and magnitude‐squared coherence (γ2‐coherence). Our results show a high degree of spatial variability and frequency dependence in the long‐period horizontal wavefield. The variable nature of long‐period horizontal noise in the ASL vault suggests that it might be highly local in nature and not easily characterized by simple physical models when overall noise levels are low, making it difficult to identify locations in the vault with lower horizontal noise. This variability could be limiting our ability to apply coherence analysis for estimating horizontal sensor self‐noise and could also complicate various indirect methods for removing long‐period horizontal noise (e.g., collocated rotational sensor or microbarograph).

Nervous branch passing through an accessory canal in the sphenozygomatic suture: the temporal branch of the zygomatic nerve.

PubMed

Akita, K; Shimokawa, T; Tsunoda, A; Sato, T

2002-05-01

A nervous branch which passes through a small canal in the sphenozygomatic suture is sometimes observed during dissection. To examine the origin, course and distribution of this nervous branch, 42 head halves of 21 Japanese cadavers (11 males, 10 females) and 142 head halves of 71 human dry skulls were used. The branch was observed in seven sides (16.7%); it originated from the communication between the lacrimal nerve and the zygomaticotemporal branch of the zygomatic nerve or from the trunk of the zygomatic nerve. In two head halves (4.8%), the branch pierced the anterior part of the temporalis muscle during its course to the skin of the anterior part of the temple. The small canal in the suture was observed in 31 head halves (21.8%) of the dry skulls. Although this nervous branch is inconstantly observed, it should be called the temporal branch of the zygomatic nerve according to the constant positional relationship to the sphenoid and zygomatic bones. According to its origin, course and distribution, this nervous branch may be considered to be influential in zygomatic and retro-orbital pain due to entrapment and tension from the temporalis muscle and/or the narrow bony canal. The French version of this article is available in the form of electronic supplementary material and can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00276-002-0027-4.

Adaptive Horizontal Gene Transfers between Multiple Cheese-Associated Fungi.

PubMed

Ropars, Jeanne; Rodríguez de la Vega, Ricardo C; López-Villavicencio, Manuela; Gouzy, Jérôme; Sallet, Erika; Dumas, Émilie; Lacoste, Sandrine; Debuchy, Robert; Dupont, Joëlle; Branca, Antoine; Giraud, Tatiana

2015-10-05

Domestication is an excellent model for studies of adaptation because it involves recent and strong selection on a few, identified traits [1-5]. Few studies have focused on the domestication of fungi, with notable exceptions [6-11], despite their importance to bioindustry [12] and to a general understanding of adaptation in eukaryotes [5]. Penicillium fungi are ubiquitous molds among which two distantly related species have been independently selected for cheese making-P. roqueforti for blue cheeses like Roquefort and P. camemberti for soft cheeses like Camembert. The selected traits include morphology, aromatic profile, lipolytic and proteolytic activities, and ability to grow at low temperatures, in a matrix containing bacterial and fungal competitors [13-15]. By comparing the genomes of ten Penicillium species, we show that adaptation to cheese was associated with multiple recent horizontal transfers of large genomic regions carrying crucial metabolic genes. We identified seven horizontally transferred regions (HTRs) spanning more than 10 kb each, flanked by specific transposable elements, and displaying nearly 100% identity between distant Penicillium species. Two HTRs carried genes with functions involved in the utilization of cheese nutrients or competition and were found nearly identical in multiple strains and species of cheese-associated Penicillium fungi, indicating recent selective sweeps; they were experimentally associated with faster growth and greater competitiveness on cheese and contained genes highly expressed in the early stage of cheese maturation. These findings have industrial and food safety implications and improve our understanding of the processes of adaptation to rapid environmental changes. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Adaptive Horizontal Gene Transfers between Multiple Cheese-Associated Fungi

PubMed Central

Ropars, Jeanne; Rodríguez de la Vega, Ricardo C.; López-Villavicencio, Manuela; Gouzy, Jérôme; Sallet, Erika; Dumas, Émilie; Lacoste, Sandrine; Debuchy, Robert; Dupont, Joëlle; Branca, Antoine; Giraud, Tatiana

2015-01-01

Summary Domestication is an excellent model for studies of adaptation because it involves recent and strong selection on a few, identified traits [1–5]. Few studies have focused on the domestication of fungi, with notable exceptions [6–11], despite their importance to bioindustry [12] and to a general understanding of adaptation in eukaryotes [5]. Penicillium fungi are ubiquitous molds among which two distantly related species have been independently selected for cheese making—P. roqueforti for blue cheeses like Roquefort and P. camemberti for soft cheeses like Camembert. The selected traits include morphology, aromatic profile, lipolytic and proteolytic activities, and ability to grow at low temperatures, in a matrix containing bacterial and fungal competitors [13–15]. By comparing the genomes of ten Penicillium species, we show that adaptation to cheese was associated with multiple recent horizontal transfers of large genomic regions carrying crucial metabolic genes. We identified seven horizontally transferred regions (HTRs) spanning more than 10 kb each, flanked by specific transposable elements, and displaying nearly 100% identity between distant Penicillium species. Two HTRs carried genes with functions involved in the utilization of cheese nutrients or competition and were found nearly identical in multiple strains and species of cheese-associated Penicillium fungi, indicating recent selective sweeps; they were experimentally associated with faster growth and greater competitiveness on cheese and contained genes highly expressed in the early stage of cheese maturation. These findings have industrial and food safety implications and improve our understanding of the processes of adaptation to rapid environmental changes. PMID:26412136

Horizontal alveolar bone loss: A periodontal orphan

PubMed Central

Jayakumar, A.; Rohini, S.; Naveen, A.; Haritha, A.; Reddy, Krishnanjeneya

2010-01-01

Background: Attempts to successfully regenerate lost alveolar bone have always been a clinician’s dream. Angular defects, at least, have a fairer chance, but the same cannot be said about horizontal bone loss. The purpose of the present study was to evaluate the prevalence of horizontal alveolar bone loss and vertical bone defects in periodontal patients; and later, to correlate it with the treatment modalities available in the literature for horizontal and vertical bone defects. Materials and Methods: The study was conducted in two parts. Part I was the radiographic evaluation of 150 orthopantomographs (OPGs) (of patients diagnosed with chronic periodontitis and seeking periodontal care), which were digitized and read using the AutoCAD 2006 software. All the periodontitis-affected teeth were categorized as teeth with vertical defects (if the defect angle was ≤45° and defect depth was ≥3 mm) or as having horizontal bone loss. Part II of the study comprised search of the literature on treatment modalities for horizontal and vertical bone loss in four selected periodontal journals. Results: Out of the 150 OPGs studied, 54 (36%) OPGs showed one or more vertical defects. Totally, 3,371 teeth were studied, out of which horizontal bone loss was found in 3,107 (92.2%) teeth, and vertical defects were found only in 264 (7.8%) of the teeth, which was statistically significant (P<.001). Search of the selected journals revealed 477 papers have addressed the treatment modalities for vertical and horizontal types of bone loss specifically. Out of the 477 papers, 461 (96.3%) have addressed vertical bone loss, and 18 (3.7%) have addressed treatment options for horizontal bone loss. Two papers have addressed both types of bone loss and are included in both categories. Conclusion: Horizontal bone loss is more prevalent than vertical bone loss but has been sidelined by researchers as very few papers have been published on the subject of regenerative treatment modalities for

Morphology-flow interactions lead to stage-selective vertical transport of larval sand dollars in shear flow.

PubMed

Clay, T W; Grünbaum, D

2010-04-01

Many larvae and other plankton have complex and variable morphologies of unknown functional significance. We experimentally and theoretically investigated the functional consequences of the complex morphologies of larval sand dollars, Dendraster excentricus (Eschscholtz), for hydrodynamic interactions between swimming and turbulent water motion. Vertical shearing flows (horizontal gradients of vertical flow) tilt organisms with simple geometries (e.g. spheres, ellipsoids), causing these organisms to move horizontally towards downwelling water and compromising their abilities to swim upwards. A biomechanical model of corresponding hydrodynamic interactions between turbulence-induced shear and the morphologically complex four-, six- and eight-armed stages of sand dollar larvae suggests that the movements of larval morphologies differ quantitatively and qualitatively across stages and shear intensities: at shear levels typical of calm conditions in estuarine and coastal environments, all modeled larval stages moved upward. However, at higher shears, modeled four- and eight-armed larvae moved towards downwelling, whereas six-armed larvae moved towards upwelling. We also experimentally quantified larval movement by tracking larvae swimming in low-intensity shear while simultaneously mapping the surrounding flow fields. Four- and eight-armed larvae moved into downwelling water, but six-armed larvae did not. Both the model and experiments suggest that stage-dependent changes to larval morphology lead to differences in larval movement: four- and eight-armed stages are more prone than the six-armed stage to moving into downwelling water. Our results suggest a mechanism by which differences can arise in the vertical distribution among larval stages. The ability to mitigate or exploit hydrodynamic interactions with shear is a functional consequence that potentially shapes larval evolution and development.

Enhancement in photo-electrochemical efficiency by reducing recombination rate in branched TiO2 nanotube array on functionalizing with ZnO micro crystals

NASA Astrophysics Data System (ADS)

Boda, Muzaffar Ahmad; Ashraf Shah, Mohammad

2018-06-01

In this study, branched TiO2 nanotube array were fabricated through electrochemical anodization process at constant voltage using third generation electrolyte. On account of morphological advantage, these nanotubes shows significant enhancement in photo-electrochemical property than compact or conventional titania nanotube array. However, their photo-electrochemical efficiency intensifies on coating with ZnO micro-crystals. ZnO coated branched TiO2 nanotube array shows a photocurrent density of 27.8 mA cm‑2 which is 1.55 times the photocurrent density (17.2 mA cm‑2) shown by bare branched titania nanotubes. The significant enhancement in photocurrent density shown by the resulting ZnO/TiO2 hybrid structure is attributed to suppression in electron–hole recombination phenomenon by offering smooth pathway to photo generated excitons on account of staggered band edge positions in individual semiconductors.

A Branch Meeting in Avon

ERIC Educational Resources Information Center

Vaughan, Kathryn; Coles, Alf

2011-01-01

The Association of Teachers of Mathematics (ATM) exists for, and is run by, its members. Branch meetings are so much more than the "grass roots" of the association--it can be a powerhouse of inspiration and creativity. In this article, the authors provide commentaries on a recent branch meeting.

Synthesis and macrophage activation of lentinan-mimic branched amino polysaccharides: curdlans having N-Acetyl-d-glucosamine branches.

PubMed

Kurita, Keisuke; Matsumura, Yuriko; Takahara, Hiroki; Hatta, Kiyoshige; Shimojoh, Manabu

2011-06-13

N-Acetyl-d-glucosamine branches were incorporated at the C-6 position of curdlan, a linear β-1,3-d-glucan, and the resulting nonnatural branched polysaccharides were evaluated in terms of the immunomodulation activities in comparison with lentinan, a β-1,3-d-glucan having d-glucose branches at C-6. To incorporate the amino sugar branches, we conducted a series of regioselective protection-deprotections of curdlan involving triphenylmethylation at C-6, phenylcarbamoylation at C-2 and C-4, and detriphenylmethylation. Subsequent glycosylation with a d-glucosamine-derived oxazoline, followed by deprotection gave rise to the branched curdlans with various substitution degrees. The products exhibited remarkable solubility in both organic solvents and water. Their immunomodulation activities were determined using mouse macrophagelike cells, and the secretions of both the tumor necrosis factor and nitric oxide proved to be significantly higher than those with lentinan. These results conclude that the amino sugar/curdlan hybrid materials are promising as a new type of polysaccharide immunoadjuvants useful for cancer chemotherapy.

Wind-Induced Reconfigurations in Flexible Branched Trees

NASA Astrophysics Data System (ADS)

Ojo, Oluwafemi; Shoele, Kourosh

2017-11-01

Wind induced stresses are the major mechanical cause of failure in trees. We know that the branching mechanism has an important effect on the stress distribution and stability of a tree in the wind. Eloy in PRL 2011, showed that Leonardo da Vinci's original observation which states the total cross section of branches is conserved across branching nodes is the best configuration for resisting wind-induced fracture in rigid trees. However, prediction of the fracture risk and pattern of a tree is also a function of their reconfiguration capabilities and how they mitigate large wind-induced stresses. In this studies through developing an efficient numerical simulation of flexible branched trees, we explore the role of the tree flexibility on the optimal branching. Our results show that the probability of a tree breaking at any point depends on both the cross-section changes in the branching nodes and the level of tree flexibility. It is found that the branching mechanism based on Leonardo da Vinci's original observation leads to a uniform stress distribution over a wide range of flexibilities but the pattern changes for more flexible systems.

Models of knot and stem development in black spruce trees indicate a shift in allocation priority to branches when growth is limited

PubMed Central

Duchateau, Emmanuel; Auty, David; Mothe, Frédéric; Longuetaud, Fleur; Ung, Chhun Huor

2015-01-01

The branch autonomy principle, which states that the growth of individual branches can be predicted from their morphology and position in the forest canopy irrespective of the characteristics of the tree, has been used to simplify models of branch growth in trees. However, observed changes in allocation priority within trees towards branches growing in light-favoured conditions, referred to as ‘Milton’s Law of resource availability and allocation,’ have raised questions about the applicability of the branch autonomy principle. We present models linking knot ontogeny to the secondary growth of the main stem in black spruce (Picea mariana (Mill.) B.S.P.), which were used to assess the patterns of assimilate allocation over time, both within and between trees. Data describing the annual radial growth of 445 stem rings and the three-dimensional shape of 5,377 knots were extracted from optical scans and X-ray computed tomography images taken along the stems of 10 trees. Total knot to stem area increment ratios (KSR) were calculated for each year of growth, and statistical models were developed to describe the annual development of knot diameter and curvature as a function of stem radial increment, total tree height, stem diameter, and the position of knots along an annual growth unit. KSR varied as a function of tree age and of the height to diameter ratio of the stem, a variable indicative of the competitive status of the tree. Simulations of the development of an individual knot showed that an increase in the stem radial growth rate was associated with an increase in the initial growth of the knot, but also with a shorter lifespan. Our results provide support for ‘Milton’s Law,’ since they indicate that allocation priority is given to locations where the potential return is the highest. The developed models provided realistic simulations of knot morphology within trees, which could be integrated into a functional-structural model of tree growth and above

Models of knot and stem development in black spruce trees indicate a shift in allocation priority to branches when growth is limited.

PubMed

Duchateau, Emmanuel; Auty, David; Mothe, Frédéric; Longuetaud, Fleur; Ung, Chhun Huor; Achim, Alexis

2015-01-01

The branch autonomy principle, which states that the growth of individual branches can be predicted from their morphology and position in the forest canopy irrespective of the characteristics of the tree, has been used to simplify models of branch growth in trees. However, observed changes in allocation priority within trees towards branches growing in light-favoured conditions, referred to as 'Milton's Law of resource availability and allocation,' have raised questions about the applicability of the branch autonomy principle. We present models linking knot ontogeny to the secondary growth of the main stem in black spruce (Picea mariana (Mill.) B.S.P.), which were used to assess the patterns of assimilate allocation over time, both within and between trees. Data describing the annual radial growth of 445 stem rings and the three-dimensional shape of 5,377 knots were extracted from optical scans and X-ray computed tomography images taken along the stems of 10 trees. Total knot to stem area increment ratios (KSR) were calculated for each year of growth, and statistical models were developed to describe the annual development of knot diameter and curvature as a function of stem radial increment, total tree height, stem diameter, and the position of knots along an annual growth unit. KSR varied as a function of tree age and of the height to diameter ratio of the stem, a variable indicative of the competitive status of the tree. Simulations of the development of an individual knot showed that an increase in the stem radial growth rate was associated with an increase in the initial growth of the knot, but also with a shorter lifespan. Our results provide support for 'Milton's Law,' since they indicate that allocation priority is given to locations where the potential return is the highest. The developed models provided realistic simulations of knot morphology within trees, which could be integrated into a functional-structural model of tree growth and above

VizieR Online Data Catalog: CCD photometry of Pal 1 (Borissova+ 1995)

NASA Astrophysics Data System (ADS)

Borissova, J.; Spassova, N.

1997-06-01

A CCD photometry of the halo cluster Palomar 1 is presented in the Thuan-Gunn photometric system. The principal sequences of the color-magnitude diagrams are delineated in different spectral bands. The color- magnitude diagrams of the cluster show a well defined red horizontal branch, a subgiant branch and a main-sequence down to about two magnitudes below the main sequence turnoff. The giant branch is absent and the brightest stars are the horizontal branch stars. The age of the cluster determined by comparison with the isochrones of Bell & VandenBerg (1987ApJS...63..335B) is consistent with an age in the interval 12-14Gyr. A distance modulus of (m-M)g0=15.38+/-0.15 magnitude and E(g-r)=0.16 has been derived. An estimate of the cluster structural parameters such as core radius and concentration parameter gives rc=1.5pc and c=1.46. A mass estimate of 1.1x103M⊙ and a mass-to-light ratio of 1.79 have been obtained using King's (1966AJ.....71...64K) method. The morphology of color-magnitude diagrams allows Pal 1 to be interpreted as probably a globular cluster rather than an old open one. For a description of the uvgr photometric system, see e.g. (1 data file).

Horizontal technology helps spark Louisiana`s Austin chalk trend

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koen, A.D.

1996-04-29

A handful of companies paced by some of the most active operators in the US are pressing the limits of horizontal technology to ramp up Cretaceous Austin chalk exploration and development (E and D) across Louisiana. Companies find applications in Louisiana for lessons learned drilling horizontal wells to produce chalk intervals in Texas in Giddings, Pearsall, and Brookeland fields. Continuing advances in horizontal well technology are helping operators deal with deeper, hotter reservoirs in more complex geological settings that typify the chalk in Louisiana. Better horizontal drilling, completion, formation evaluation, and stimulation techniques have enabled operators to produce oil andmore » gas from formations previously thought to be uneconomical. Most of the improved capabilities stem from better horizontal tools. Horizontal drilling breakthroughs include dual powered mud motors and retrievable whipstocks, key links in the ability to drill wells with more than one horizontal lateral. Better geosteering tools have enabled operators to maintain horizontal wellbores in desired intervals by signaling bit positions downhole while drilling. This paper reviews the technology and provides a historical perspective on the various drilling programs which have been completed in this trend. It also makes predictions on future drilling successes.« less

Why mushrooms form gills: efficiency of the lamellate morphology

PubMed Central

FISCHER, Mark W. F.; MONEY, Nicholas P.

2009-01-01

Gilled mushrooms are produced by multiple orders within the Agaricomycetes. Some species form a single array of unbranched radial gills beneath their caps, many others produce multiple files of lamellulae between the primary gills, and branched gills are also common. In this largely theoretical study we modeled the effects of different gill arrangements on the total surface area for spore production. Relative to spore production over a flat surface, gills achieve a maximum 20-fold increase in surface area. The branching of gills produces the same increase in surface area as the formation of freestanding lamellulae (short gills). The addition of lamellulae between every second gill would offer a slightly greater increase in surface area in comparison to the addition of lamellulae between every pair of opposing gills, but this morphology does not appear in nature. Analysis of photographs of mushrooms demonstrates an excellent match between natural gill arrangements and configurations predicted by our model. PMID:20965062

The effects of hydroxy fatty acids on the hyphal branching of germinated spores of AM fungi.

PubMed

Nagahashi, Gerald; Douds, David D

2011-01-01

Two hydroxy fatty acids, tentatively identified previously in carrot root exudates, were tested for their effects on hyphal growth of the arbuscular mycorrhizal (AM) fungus, Gigaspora gigantea (Nicol. and Gerd.) Gerdemann and Trappe. Best results were achieved with a long-term bioassay (7-8d) with nanomolar concentrations throughout the Petri dish in contrast to the rapid microinjection bioassay (16-24h) in which nanogram quantities were injected near growing hyphal tips. When 5nM 2-hydroxy fatty acids of various chain length were tested, the length of the hydroxyl fatty acid was significant since only 2-hydroxytetradecanoic acid (2OH-TDA) and to a slightly lesser degree, 2-hydroxydodecanoic acid (2OH-DDA) induced a hyphal growth response while 2-hydroxydecanoic acid (2OH-DA) and 2-hydroxyhexadecanoic (2OH-HDA) acid did not. The position of the hydroxyl group was critical since 5nM 3-hydroxytetradecanoic acid (3OH-TDA) had no effect on hyphal growth. The length of the non-hydroxy containing straight chain fatty acid, per se, did not appear significant since none of these fatty acids had an effect on hyphal growth. The morphological growth response promoted by 2OH-TDA consisted of multiple lateral branches, spaced fairly regularly apart, along the primary germ tubes as well as some lateral branch formation off the major secondary hyphae. This growth response was identical to that observed when germinated spores were allowed to grow towards cultured carrot roots in vitro. This response to 2OH-TDA also was observed with an unidentified Gigaspora species but no morphological response was observed with Glomus intraradices Schenck and Smith. The results indicate that 2-hydroxy fatty acids are another putative category of root exudate signals perceived by Gigaspora species, stimulating an increase in elongated lateral branches. Published by Elsevier Ltd.

Stand age and fine root biomass, distribution and morphology in a Norway spruce chronosequence in southeast Norway.

PubMed

Børja, Isabella; De Wit, Heleen A; Steffenrem, Arne; Majdi, Hooshang

2008-05-01

We assessed the influence of stand age on fine root biomass and morphology of trees and understory vegetation in 10-, 30-, 60- and 120-year-old Norway spruce stands growing in sandy soil in southeast Norway. Fine root (< 1, 1-2 and 2-5 mm in diameter) biomass of trees and understory vegetation (< 2 mm in diameter) was sampled by soil coring to a depth of 60 cm. Fine root morphological characteristics, such as specific root length (SRL), root length density (RLD), root surface area (RSA), root tip number and branching frequency (per unit root length or mass), were determined based on digitized root data. Fine root biomass and morphological characteristics related to biomass (RLD and RSA) followed the same tendency with chronosequence and were significantly higher in the 30-year-old stand and lower in the 10-year-old stand than in the other stands. Among stands, mean fine root (< 2 mm) biomass ranged from 49 to 398 g m(-2), SLR from 13.4 to 19.8 m g(-1), RLD from 980 to 11,650 m m(-3) and RSA from 2.4 to 35.4 m(2) m(-3). Most fine root biomass of trees was concentrated in the upper 20 cm of the mineral soil and in the humus layer (0-5 cm) in all stands. Understory fine roots accounted for 67 and 25% of total fine root biomass in the 10- and 120-year-old stands, respectively. Stand age had no affect on root tip number or branching frequency, but both parameters changed with soil depth, with increasing number of root tips and decreasing branching frequency with increasing soil depth for root fractions < 2 mm in diameter. Specific (mass based) root tip number and branching density were highest for the finest roots (< 1 mm) in the humus layer. Season (spring or fall) had no effect on tree fine root biomass, but there was a small and significant increase in understory fine root biomass in fall relative to spring. All morphological characteristics showed strong seasonal variation, especially the finest root fraction, with consistently and significantly higher values in

Implementing vertical and horizontal engineering students' integration and assessment of consequence academic achievement

NASA Astrophysics Data System (ADS)

Al-Zubaidy, Sarim; Abdulaziz, Nidhal; Dashtpour, Reza

2012-08-01

Recent scholarship references indicate that integration of the student body can result in an enhanced learning experience for students and also greater satisfaction. This paper reports the results of a case study whereby mechanical engineering students studying at a newly established branch campus in Dubai of a British university were exposed to vertical and horizontal integration. Different activities have been embedded to ensure that students integrated and worked together with their peers and colleagues at different levels. The implemented processes and practices led to improved academic achievements, which were better than those of a similar cohort of students where no effort had been made to integrate. The analysis revealed that cooperative learning and the degree of academic support provided by teachers are positively and directly correlated with academic as well as the students' own sense of personal achievement. The results are discussed in light of previous research and with reference to the cultural context of the study.

Sloppy morphological tuning in identified neurons of the crustacean stomatogastric ganglion

PubMed Central

Otopalik, Adriane G; Goeritz, Marie L; Sutton, Alexander C; Brookings, Ted; Guerini, Cosmo; Marder, Eve

2017-01-01

Neuronal physiology depends on a neuron’s ion channel composition and unique morphology. Variable ion channel compositions can produce similar neuronal physiologies across animals. Less is known regarding the morphological precision required to produce reliable neuronal physiology. Theoretical studies suggest that moraphology is tightly tuned to minimize wiring and conduction delay of synaptic events. We utilize high-resolution confocal microscopy and custom computational tools to characterize the morphologies of four neuron types in the stomatogastric ganglion (STG) of the crab Cancer borealis. Macroscopic branching patterns and fine cable properties are variable within and across neuron types. We compare these neuronal structures to synthetic minimal spanning neurite trees constrained by a wiring cost equation and find that STG neurons do not adhere to prevailing hypotheses regarding wiring optimization principles. In this highly modulated and oscillating circuit, neuronal structures appear to be governed by a space-filling mechanism that outweighs the cost of inefficient wiring. DOI: http://dx.doi.org/10.7554/eLife.22352.001 PMID:28177286

Solving vertical and horizontal well hydraulics problems analytically in Cartesian coordinates with vertical and horizontal anisotropies

NASA Astrophysics Data System (ADS)

Batu, Vedat

2012-01-01

SummaryA new generalized three-dimensional analytical solution is developed for a partially-penetrating vertical rectangular parallelepiped well screen in a confined aquifer by solving the three-dimensional transient ground water flow differential equation in x- y- z Cartesian coordinates system for drawdown by taking into account the three principal hydraulic conductivities ( Kx, Ky, and Kz) along the x- y- z coordinate directions. The fully penetrating screen case becomes equivalent to the single vertical fracture case of Gringarten and Ramey (1973). It is shown that the new solution and Gringarten and Ramey solution (1973) match very well. Similarly, it is shown that this new solution for a horizontally tiny fully penetrating parallelepiped rectangular parallelepiped screen case match very well with Theis (1935) solution. Moreover, it is also shown that the horizontally tiny partially-penetrating parallelepiped rectangular well screen case of this new solution match very well with Hantush (1964) solution. This new analytical solution can also cover a partially-penetrating horizontal well by representing its screen interval with vertically tiny rectangular parallelepiped. Also the solution takes into account both the vertical anisotropy ( azx = Kz/ Kx) as well as the horizontal anisotropy ( ayx = Ky/ Kx) and has potential application areas to analyze pumping test drawdown data from partially-penetrating vertical and horizontal wells by representing them as tiny rectangular parallelepiped as well as line sources. The solution has also potential application areas for a partially-penetrating parallelepiped rectangular vertical fracture. With this new solution, the horizontal anisotropy ( ayx = Ky/ Kx) in addition to the vertical anisotropy ( azx = Kz/ Kx) can also be determined using observed drawdown data. Most importantly, with this solution, to the knowledge of the author, it has been shown the first time in the literature that some well-known well hydraulics

Nuclear component horizontal seismic restraint

DOEpatents

Snyder, Glenn J.

1988-01-01

A nuclear component horizontal seismic restraint. Small gaps limit horizontal displacement of components during a seismic occurrence and therefore reduce dynamic loadings on the free lower end. The reactor vessel and reactor guard vessel use thicker section roll-forged rings welded between the vessel straight shell sections and the bottom hemispherical head sections. The inside of the reactor guard vessel ring forging contains local vertical dovetail slots and upper ledge pockets to mount and retain field fitted and installed blocks. As an option, the horizontal displacement of the reactor vessel core support cone can be limited by including shop fitted/installed local blocks in opposing alignment with the reactor vessel forged ring. Beams embedded in the wall of the reactor building protrude into apertures in the thermal insulation shell adjacent the reactor guard vessel ring and have motion limit blocks attached thereto to provide to a predetermined clearance between the blocks and reactor guard vessel ring.

46 CFR 169.690 - Lighting branch circuits.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Lighting branch circuits. 169.690 Section 169.690... Machinery and Electrical Electrical Installations on Vessels of 100 Gross Tons and Over § 169.690 Lighting branch circuits. Each lighting branch circuit must meet the requirements of § 111.75-5 of this chapter...

Enhanced total neurite outgrowth and secondary branching in dorsal root ganglion neurons elicited by low intensity pulsed ultrasound.

PubMed

Ventre, Daniel; Puzan, Marissa; Ashbolt, Emily; Koppes, Abigail

2018-04-17

Despite the prevalence of peripheral nerve injuries (PNI), challenges remain in restoring full functionality to those afflicted. For recovery to occur, axons must extend across the injury site to connect with distal targets, where injury gap size is a critical factor in the probability of restoration of function. Current clinical therapies often achieve limited neural regeneration, motivating the development of new therapeutic interventions such as biophysical stimulation. To investigate the potential for low intensity, pulsed ultrasonic simulation (LIPUS) to impact peripheral nerve regeneration, primary neonatal rat dorsal root ganglion neurons were examined in vitro in response to ultrasound (US). Dissociated neurons were stimulated with varied acoustic power (low, medium, high) and their morphometrics, including total outgrowth, branching, and length, were analyzed acutely after 18 h of growth. Results show US increases total neurite outgrowth by 2.83-fold compared to unstimulated controls at the highest power. Neurite branching at medium and high-power US increased approximately 2-fold compared to controls, while low stimulation exhibited more muted trends. Neurite branching is also impacted by US, with medium and high power eliciting the highest branching, of approximately 2-fold compared to low power and unstimulated controls. These results demonstrate that US stimulation of DRG neurons in vitro impacts neurite morphology and enhances total extension, indicating the potential for advancing and understanding driving mechanisms of ultrasonic therapies for peripheral nerve regeneration.

The development of the red giant branch. I - Theoretical evolutionary sequences

NASA Technical Reports Server (NTRS)

Sweigart, Allen V.; Greggio, Laura; Renzini, Alvio

1989-01-01

A grid of 100 evolutionary sequences extending from the zero-age main sequence to the onset of helium burning has been computed for stellar masses between 1.4 and 3.4 solar masses, helium abundances of 0.20 and 0.30, and heavy-element abundances of 0.004, 0.01, and 0.04. Using these computations the transition in the morphology of the red giant branch (RGB) between low-mass stars, which have an extended and luminous first RGB phase prior to helium ignition, and intermediate-mass stars, which do not, is investigated. Extensive tabulations of the numerical results are provided to aid in applying these sequences. The effects of the first dredge-up on the surface helium and CNO abundances of the sequences is discussed.

Horizontal atmospheric turbulence, beam propagation, and modeling

NASA Astrophysics Data System (ADS)

Wilcox, Christopher C.; Santiago, Freddie; Martinez, Ty; Judd, K. Peter; Restaino, Sergio R.

2017-05-01

The turbulent effect from the Earth's atmosphere degrades the performance of an optical imaging system. Many studies have been conducted in the study of beam propagation in a turbulent medium. Horizontal beam propagation and correction presents many challenges when compared to vertical due to the far harsher turbulent conditions and increased complexity it induces. We investigate the collection of beam propagation data, analysis, and use for building a mathematical model of the horizontal turbulent path and the plans for an adaptive optical system to use this information to correct for horizontal path atmospheric turbulence.

Branched Hamiltonians and supersymmetry

DOE PAGES

Curtright, Thomas L.; Zachos, Cosmas K.

2014-03-21

Some examples of branched Hamiltonians are explored both classically and in the context of quantum mechanics, as recently advocated by Shapere and Wilczek. These are in fact cases of switchback potentials, albeit in momentum space, as previously analyzed for quasi-Hamiltonian chaotic dynamical systems in a classical setting, and as encountered in analogous renormalization group flows for quantum theories which exhibit RG cycles. In conclusion, a basic two-worlds model, with a pair of Hamiltonian branches related by supersymmetry, is considered in detail.

A method for evaluating horizontal well pumping tests.

PubMed

Langseth, David E; Smyth, Andrew H; May, James

2004-01-01

Predicting the future performance of horizontal wells under varying pumping conditions requires estimates of basic aquifer parameters, notably transmissivity and storativity. For vertical wells, there are well-established methods for estimating these parameters, typically based on either the recovery from induced head changes in a well or from the head response in observation wells to pumping in a test well. Comparable aquifer parameter estimation methods for horizontal wells have not been presented in the ground water literature. Formation parameter estimation methods based on measurements of pressure in horizontal wells have been presented in the petroleum industry literature, but these methods have limited applicability for ground water evaluation and are based on pressure measurements in only the horizontal well borehole, rather than in observation wells. This paper presents a simple and versatile method by which pumping test procedures developed for vertical wells can be applied to horizontal well pumping tests. The method presented here uses the principle of superposition to represent the horizontal well as a series of partially penetrating vertical wells. This concept is used to estimate a distance from an observation well at which a vertical well that has the same total pumping rate as the horizontal well will produce the same drawdown as the horizontal well. This equivalent distance may then be associated with an observation well for use in pumping test algorithms and type curves developed for vertical wells. The method is shown to produce good results for confined aquifers and unconfined aquifers in the absence of delayed yield response. For unconfined aquifers, the presence of delayed yield response increases the method error.

Changes in morphology of retinal ganglion cells with eccentricity in retinal degeneration.

PubMed

Anderson, E E; Greferath, U; Fletcher, E L

2016-05-01

Ganglion cells are the output neurons of the retina and are known to remodel during the subtle plasticity changes that occur following the death of photoreceptors in inherited retinal degeneration. We examine the influence of retinal eccentricity on anatomical remodelling and ganglion cell morphology well after photoreceptor loss. Rd1 mice that have a mutation in the β subunit of phosphodiesterase 6 were used as a model of retinal degeneration and gross remodelling events were examined by processing serial sections for immunocytochemistry. Retinal wholemounts from rd1-Thy1 and control Thy1 mice that contained a fluorescent protein labelling a subset of ganglion cells were processed for immunohistochemistry at 11 months of age. Ganglion cells were classified based on their soma size, dendritic field size and dendritic branching pattern and their dendritic fields were analysed for their length, area and quantity of branching points. Overall, more remodelling was found in the central compared with the peripheral retina. In addition, the size and complexity of A2, B1, C1 and D type ganglion cells located in the central region of the retina decreased. We propose that the changes in ganglion cell morphology are correlated with remodelling events in these regions and impact the function of retinal circuitry in the degenerated retina.

Morphological evidences in circumvallate papilla and von Ebners' gland development in mice

PubMed Central

Sohn, Wern-Joo; Gwon, Gi-Jeong; An, Chang-Hyeon; Moon, Cheil; Bae, Yong-Chul; Yamamoto, Hitoshi; Lee, Sanggyu

2011-01-01

In rodents, the circumvallate papilla (CVP), with its underlying minor salivary gland, the von Ebners' gland (VEG), is located on the dorsal surface of the posterior tongue. Detailed morphological processes to form the proper structure of CVP and VEG have not been properly elucidated. In particular, the specific localization patterns of taste buds in CVP and the branching formation of VEG have not yet been elucidated. To understand the developmental mechanisms underlying CVP and VEG formation, detailed histological observations of CVP and VEG were examined using a three-dimensional computer-aided reconstruction method with serial histological sections and pan-Cytokeratins immunostainings. In addition, to define the developmental processes in CVP and VEG formation, we examined nerve innervations and cell proliferation using microinjections of AM1-43 and immunostainings with various markers, including phosphoinositide 3-kinase, Ki-67, PGP9.5, and Ulex europaeus agglutinin 1 (UEA1). Results revealed specific morphogenesis of CVP and VEG with nerve innervations patterns, evaluated by the coincided localization patterns of AM1-43 and UEA1. Based on these morphological and immunohistochemical results, we suggest that nerve innervations and cell proliferations play important roles in the positioning of taste buds in CVP and branching morphogenesis of VEG in tongue development. PMID:22254156

Branching, Superdiffusion and Stress Relaxation in Surfactant Micelles

NASA Astrophysics Data System (ADS)

Sureshkumar, R.; Dhakal, S.; Syracuse University Team

2016-11-01

We investigate the mechanism of branch formation and its effects on the dynamics and rheology of a model cationic micellar fluid using molecular dynamics (MD) simulations. Branched structures are formed upon increasing counter ion density. A sharp decrease in the solution viscosity with increasing salinity has long been attributed to the sliding motion of micellar branches along the main chain. Simulations not only provide firm evidence of branch sliding in real time, but also show enhanced diffusion of surfactants by virtue of such motion. Insights into the mechanism of stress relaxation associated with branch sliding will be discussed. Specifically, an externally imposed stress damps out more quickly in a branched system compared to that in an unbranched one. NSF Grants 1049489, 1049454.

Geology of the Cane Branch and Helton Branch watershed areas, McCreary County, Kentucky

USGS Publications Warehouse

Lyons, Erwin J.

1957-01-01

Cane Branch and Helton Branch in McCreary County, Kentucky, are about 1.4 miles apart (fig. 1). Can Branch, which is about 2.1 miles long, emptied into Hughes Fork of Beaver Creek. Its watershed area of about 1.5 square miles lies largely in the Wiborf 7 1/2-minute quadrangle (SW/4 Cumberland Falls 15-minute quadrangle), but the downstream part of the area extends northward into the Hail 7 1/2-minute quadrangle (NW/4 Cumberland Falls 15-minute quadrangle). Helton Branch, which is about 1.1 miles long, has two tributaries and empties into Little Hurricane Fork of Beaver Creek. It drains an area of about 0.8 square mile of while about 0.5 square mile is in the Hail quadrangle and the remainder in the Wilborg quadrangle. The total relief in the Can Branch area is about 500 feet and in the Helton Branch area about 400 feet. Narrow, steep-sided to canyon-like valley and winding ridges, typical of the Pottsville escarpment region, are characteristic of both areas. Thick woods and dense undergrowth cover much of the two areas. Field mapping was done on U.S. Geological Survey 7 1/2-minute maps having a scale of 1:24,000 and a contour interval of 20 feet. Elevations of lithologic contacts were determined with a barometer and a hand level. Aerial photographs were used principally to trace the cliffs formed by sandstone and conglomerate ledges. Exposures, except for those of the cliff- and ledge-forming sandstone and conglomerates, are not abundant. The most complete stratigraphic sections (secs. 3 and 4, fig. 2) in the two areas are exposed in cuts of newly completed Forest Service roads, but the rick in the upper parts of the exposures is weathered. To supplement these sections, additional sections were measured in cuts along the railroad and main highways in nor near the watersheds.

The horizontal computerized rotational impulse test.

PubMed

Furman, Joseph M; Shirey, Ian; Roxberg, Jillyn; Kiderman, Alexander

2016-01-01

Whole-body impulsive rotations were used to overcome several limitations associated with manual head impulse testing. A computer-controlled rotational chair delivered brief, whole-body, earth-vertical axis yaw impulsive rotations while eye movements were measured using video-oculography. Results from an unselected group of 20 patients with dizziness and a group of 22 control subjects indicated that the horizontal computerized rotational head impulse test (crHIT) is well-tolerated and provides an estimate of unidirectional vestibulo-ocular reflex gain comparable to results from caloric testing. This study demonstrates that the horizontal crHIT is a new assessment tool that overcomes many of the limitations of manual head impulse testing and provides a reliable laboratory-based measure of unilateral horizontal semicircular canal function.

The Process of Horizontal Differentiation: Two Models.

ERIC Educational Resources Information Center

Daft, Richard L.; Bradshaw, Patricia J.

1980-01-01

Explores the process of horizontal differentiation by examining events leading to the establishment of 30 new departments in five universities. Two types of horizontal differentiation processes--administrative and academic--were observed and each was associated with different organizational conditions. (Author/IRT)

Fuzzy branching temporal logic.

PubMed

Moon, Seong-ick; Lee, Kwang H; Lee, Doheon

2004-04-01

Intelligent systems require a systematic way to represent and handle temporal information containing uncertainty. In particular, a logical framework is needed that can represent uncertain temporal information and its relationships with logical formulae. Fuzzy linear temporal logic (FLTL), a generalization of propositional linear temporal logic (PLTL) with fuzzy temporal events and fuzzy temporal states defined on a linear time model, was previously proposed for this purpose. However, many systems are best represented by branching time models in which each state can have more than one possible future path. In this paper, fuzzy branching temporal logic (FBTL) is proposed to address this problem. FBTL adopts and generalizes concurrent tree logic (CTL*), which is a classical branching temporal logic. The temporal model of FBTL is capable of representing fuzzy temporal events and fuzzy temporal states, and the order relation among them is represented as a directed graph. The utility of FBTL is demonstrated using a fuzzy job shop scheduling problem as an example.

Robust syntaxin-4 immunoreactivity in mammalian horizontal cell processes

PubMed Central

HIRANO, ARLENE A.; BRANDSTÄTTER, JOHANN HELMUT; VILA, ALEJANDRO; BRECHA, NICHOLAS C.

2009-01-01

Horizontal cells mediate inhibitory feed-forward and feedback communication in the outer retina; however, mechanisms that underlie transmitter release from mammalian horizontal cells are poorly understood. Toward determining whether the molecular machinery for exocytosis is present in horizontal cells, we investigated the localization of syntaxin-4, a SNARE protein involved in targeting vesicles to the plasma membrane, in mouse, rat, and rabbit retinae using immunocytochemistry. We report robust expression of syntaxin-4 in the outer plexiform layer of all three species. Syntaxin-4 occurred in processes and tips of horizontal cells, with regularly spaced, thicker sandwich-like structures along the processes. Double labeling with syntaxin-4 and calbindin antibodies, a horizontal cell marker, demonstrated syntaxin-4 localization to horizontal cell processes; whereas, double labeling with PKC antibodies, a rod bipolar cell (RBC) marker, showed a lack of co-localization, with syntaxin-4 immunolabeling occurring just distal to RBC dendritic tips. Syntaxin-4 immunolabeling occurred within VGLUT-1-immunoreactive photoreceptor terminals and underneath synaptic ribbons, labeled by CtBP2/RIBEYE antibodies, consistent with localization in invaginating horizontal cell tips at photoreceptor triad synapses. Vertical sections of retina immunostained for syntaxin-4 and peanut agglutinin (PNA) established that the prominent patches of syntaxin-4 immunoreactivity were adjacent to the base of cone pedicles. Horizontal sections through the OPL indicate a one-to-one co-localization of syntaxin-4 densities at likely all cone pedicles, with syntaxin-4 immunoreactivity interdigitating with PNA labeling. Pre-embedding immuno-electron microscopy confirmed the subcellular localization of syntaxin-4 labeling to lateral elements at both rod and cone triad synapses. Finally, co-localization with SNAP-25, a possible binding partner of syntaxin-4, indicated co-expression of these SNARE proteins in

Mathematical Relationships between Neuron Morphology and Neurite Growth Dynamics in Drosophila melanogaster Larva Class IV Sensory Neurons

NASA Astrophysics Data System (ADS)

Ganguly, Sujoy; Liang, Xin; Grace, Michael; Lee, Daniel; Howard, Jonathon

The morphology of neurons is diverse and reflects the diversity of neuronal functions, yet the principles that govern neuronal morphogenesis are unclear. In an effort to better understand neuronal morphogenesis we will be focusing on the development of the dendrites of class IV sensory neuron in Drosophila melanogaster. In particular we attempt to determine how the the total length, and the number of branches of dendrites are mathematically related to the dynamics of neurite growth and branching. By imaging class IV neurons during early embryogenesis we are able to measure the change in neurite length l (t) as a function of time v (t) = dl / dt . We found that the distribution of v (t) is well characterized by a hyperbolic secant distribution, and that the addition of new branches per unit time is well described by a Poisson process. Combining these measurements with the assumption that branching occurs with equal probability anywhere along the dendrite we were able to construct a mathematical model that provides reasonable agreement with the observed number of branches, and total length of the dendrites of the class IV sensory neuron.

Differential influence of clonal integration on morphological and growth responses to light in two invasive herbs.

PubMed

Xu, Cheng-Yuan; Schooler, Shon S; Van Klinken, Rieks D

2012-01-01

In contrast to seeds, high sensitivity of vegetative fragments to unfavourable environments may limit the expansion of clonal invasive plants. However, clonal integration promotes the establishment of propagules in less suitable habitats and may facilitate the expansion of clonal invaders into intact native communities. Here, we examine the influence of clonal integration on the morphology and growth of ramets in two invasive plants, Alternanthera philoxeroides and Phyla canescens, under varying light conditions. In a greenhouse experiment, branches, connected ramets and severed ramets of the same mother plant were exposed under full sun and 85% shade and their morphological and growth responses were assessed. The influence of clonal integration on the light reaction norm (connection×light interaction) of daughter ramets was species-specific. For A. philoxeroides, clonal integration evened out the light response (total biomass, leaf mass per area, and stem number, diameter and length) displayed in severed ramets, but these connection×light interactions were largely absent for P. canescens. Nevertheless, for both species, clonal integration overwhelmed light effect in promoting the growth of juvenile ramets during early development. Also, vertical growth, as an apparent shade acclimation response, was more prevalent in severed ramets than in connected ramets. Finally, unrooted branches displayed smaller organ size and slower growth than connected ramets, but the pattern of light reaction was similar, suggesting mother plants invest in daughter ramets prior to their own branches. Clonal integration modifies light reaction norms of morphological and growth traits in a species-specific manner for A. philoxeroides and P. canescens, but it improves the establishment of juvenile ramets of both species in light-limiting environments by promoting their growth during early development. This factor may be partially responsible for their ability to successfully colonize

A case of recurrence of congenital ocular toxoplasmosis with frosted branch angiitis (ocular toxoplasmosis with frosted branch angiitis).

PubMed

Suzuki, Takahiro; Onouchi, Hiromi; Nakagawa, Yoshihiro; Oohashi, Hideki; Kaiken, Han; Kawai, Kenji

2010-12-20

To describe a case of recurrence of congenital ocular toxoplasmosis with frosted branch angiitis. A 24-year-old woman presented with hyperemia in her right eye. Medical history included epilepsy at age 14 and mild mental retardation. Iridocyclitis and vitreous opacity were observed in the right eye, and furthermore widespread retinal vessel sheathing due to frosted branch angiitis was seen. Acyclovir was initiated for acute retinal necrosis with frosted branch angiitis. One week later, serologic tests showed elevated toxoplasma antibody level and toxoplasma antibody IgG level, and a white retinal exudative lesion with unclear margins was noted. Therefore, acetylspiramycin and prednisolone were initiated for a recurrence of congenital ocular toxoplasmosis. After treatment, inflammation subsided, the exudative lesion shrank, and the frosted branch angiitis improved. We encountered a case of ocular toxoplasmosis due to recurrence of congenital toxoplasmosis with frosted branch angiitis. The clinical symptoms of ocular toxoplasmosis can be varied and the diagnosis should be kept in mind.

Coulomb branches with complex singularities

NASA Astrophysics Data System (ADS)

Argyres, Philip C.; Martone, Mario

2018-06-01

We construct 4d superconformal field theories (SCFTs) whose Coulomb branches have singular complex structures. This implies, in particular, that their Coulomb branch coordinate rings are not freely generated. Our construction also gives examples of distinct SCFTs which have identical moduli space (Coulomb, Higgs, and mixed branch) geometries. These SCFTs thus provide an interesting arena in which to test the relationship between moduli space geometries and conformal field theory data. We construct these SCFTs by gauging certain discrete global symmetries of N = 4 superYang-Mills (sYM) theories. In the simplest cases, these discrete symmetries are outer automorphisms of the sYM gauge group, and so these theories have lagrangian descriptions as N = 4 sYM theories with disconnected gauge groups.

Variability of the inclination of anatomic horizontal reference planes of the craniofacial complex in relation to the true horizontal line in orthognathic patients.

PubMed

Zebeib, Ameen M; Naini, Farhad B

2014-12-01

The purpose of this study was to assess the reliability of the Frankfort horizontal (FH), sella-nasion horizontal, and optic planes in terms of their variabilities in relation to a true horizontal line in orthognathic surgery patients. Thirty-six consecutive presurgical orthognathic patients (13 male, 23 female; age range, 16-35 years; 30 white, 6 African Caribbean) had lateral cephalometric radiographs taken in natural head position, with a plumb line orientating the true vertical line, and the true horizontal line perpendicular to the true vertical. The inclinations of the anatomic reference planes were compared with the true horizontal. The FH plane was found to be on average closest to the true horizontal, with a mean of -1.6° (SD, 3.4°), whereas the sella-nasion horizontal and the optic plane had means of 2.1° (SD, 5.1°) and 3.2° (SD, 4.7°), respectively. The FH showed the least variability of the 3 anatomic planes. The ranges of variability were high for all anatomic planes: -8° to 8° for the FH, -8° to 15° for the sella-nasion horizontal, and -6° to 13° for the optic plane. No significant differences were found in relation to patients' sex, skeletal patterns, or ethnic backgrounds. The clinically significant variability in the inclinations of anatomic reference planes in relation to the true horizontal plane makes their use unreliable in orthognathic patients. Copyright © 2014 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Disassortativity of random critical branching trees

NASA Astrophysics Data System (ADS)

Kim, J. S.; Kahng, B.; Kim, D.

2009-06-01

Random critical branching trees (CBTs) are generated by the multiplicative branching process, where the branching number is determined stochastically, independent of the degree of their ancestor. Here we show analytically that despite this stochastic independence, there exists the degree-degree correlation (DDC) in the CBT and it is disassortative. Moreover, the skeletons of fractal networks, the maximum spanning trees formed by the edge betweenness centrality, behave similarly to the CBT in the DDC. This analytic solution and observation support the argument that the fractal scaling in complex networks originates from the disassortativity in the DDC.

Horizontal Launch: A Versatile Concept for Assured Space Access

NASA Technical Reports Server (NTRS)

Bartolotta, Paul; Wilhite, Alan W.; Schaffer, Mark; Voland, Randall T.; Huebner, Larry

2011-01-01

The vision of horizontal launch is the capability to provide a mobile launch pad that can use existing aircraft runways, cruise above weather, loiter for mission instructions, and achieve precise placement for orbital intercept, rendezvous, or reconnaissance. Another compelling benefit of horizontal launch is that today s ground-based vertical launch pads are a single earthquake, hurricane, or terrorist attack away from disruption of critical U.S. launch capabilities. The study did not attempt to design a new system concept for horizontal launch, but rather focused on the refinement of many previously-studied horizontal launch concepts. Because of the large number of past horizontal launch studies, a process was developed to narrow the number of concepts through prescreening, screening, and evaluation of point designs. The refinement process was not intended to select the "best" concept, but rather to establish the feasibility of horizontal launch from a balanced assessment of figures of merit and to identify potential concepts that warrant further exploration.

Inter-generational micro-class mobility during and after socialism: The power, education, autonomy, capital, and horizontal (PEACH) model in Hungary.

PubMed

Lippényi, Zoltán; Gerber, Theodore P

2016-07-01

We propose a theoretical model of how occupational mobility operates differently under socialism than under market regimes. Our model specifies four vertical dimensions of occupational resources-power, education, autonomy, and capital-plus a horizontal dimension consisting of linkages among occupations in the same economic branch. Given the nature of state socialist political-economic institutions, we expect power to exhibit much stronger effects in the socialist mobility regime, while autonomy and capital should play greater stratifying roles after the market transition. Education should have stable effects, and horizontal linkages should diminish in strength with market reforms. We estimate our model's parameters using data from surveys conducted in Hungary during and after the socialist period. We adopt a micro-class approach, though we test it against approaches that use more aggregated class categories. Our model provides a superior fit to other mobility models, and our results confirm our hypotheses about the distinctive features of the state socialist mobility regime. Mobility researchers often look for common patterns characterizing mobility in all industrialized societies. Our findings suggest that national institutions can produce fundamentally distinct patterns of mobility. Copyright © 2016 Elsevier Inc. All rights reserved.

Acoustic, genetic and morphological variations within the katydid Gampsocleis sedakovii (Orthoptera, Tettigonioidea)

PubMed Central

Zhang, Xue; Wen, Ming; Li, Junjian; Zhu, Hui; Wang, Yinliang; Ren, Bingzhong

2015-01-01

Abstract In an attempt to explain the variation within this species and clarify the subspecies classification, an analysis of the genetic, calling songs, and morphological variations within the species Gampsocleis sedakovii is presented from Inner Mongolia, China. Recordings were compared of the male calling songs and analysis performed of selected acoustic variables. This analysis is combined with sequencing of mtDNA - COI and examination of morphological traits to perform cluster analyses. The trees constructed from different datasets were structurally similar, bisecting the six geographical populations studied. Based on two large branches in the analysis, the species Gampsocleis sedakovii was partitioned into two subspecies, Gampsocleis sedakovii sedakovii (Fischer von Waldheim, 1846) and Gampsocleis sedakovii obscura (Walker, 1869). Comparing all the traits, the individual of Elunchun (ELC) was the intermediate type in this species according to the acoustic, genetic, and morphological characteristics. This study provides evidence for insect acoustic signal divergence and the process of subspeciation. PMID:26692795

Pacific Coastal Ecology Branch: Research Overview

EPA Science Inventory

The Pacific Coastal Ecology Branch, Newport, Oregon is part of the Western Ecology Division of the National Health and Environmental Effects Research Laboratory of the U.S. EPA. The Branch conducts research and provides scientific technical support to Headquarters and Regional O...

Preparation of Horizontal Slices of Adult Mouse Retina for Electrophysiological Studies.

PubMed

Feigenspan, Andreas; Babai, Norbert Zsolt

2017-01-27

Vertical slice preparations are well established to study circuitry and signal transmission in the adult mammalian retina. The plane of sectioning in these preparations is perpendicular to the retinal surface, making it ideal for the study of radially oriented neurons like photoreceptors and bipolar cells. However, the large dendritic arbors of horizontal cells, wide-field amacrine cells, and ganglion cells are mostly truncated, leaving markedly reduced synaptic activity in these cells. Whereas ganglion cells and displaced amacrine cells can be studied in a whole-mounted preparation of the retina, horizontal cells and amacrine cells located in the inner nuclear layer are only poorly accessible for electrodes in whole retina tissue. To achieve maximum accessibility and synaptic integrity, we developed a horizontal slice preparation of the mouse retina, and studied signal transmission at the synapse between photoreceptors and horizontal cells. Horizontal sectioning allows (1) easy and unambiguous visual identification of horizontal cell bodies for electrode targeting, and (2) preservation of the extended horizontal cell dendritic fields, as a prerequisite for intact and functional cone synaptic input to horizontal cell dendrites. Horizontal cells from horizontal slices exhibited tonic synaptic activity in the dark, and they responded to brief flashes of light with a reduction of inward current and diminished synaptic activity. Immunocytochemical evidence indicates that almost all cones within the dendritic field of a horizontal cell establish synapses with its peripheral dendrites. The horizontal slice preparation is therefore well suited to study the physiological properties of horizontally extended retinal neurons as well as sensory signal transmission and integration across selected synapses.

Concentration gradient induced morphology evolution of silica nanostructure growth on photoresist-derived carbon micropatterns

NASA Astrophysics Data System (ADS)

Liu, Dan; Shi, Tielin; Xi, Shuang; Lai, Wuxing; Liu, Shiyuan; Li, Xiaoping; Tang, Zirong

2012-09-01

The evolution of silica nanostructure morphology induced by local Si vapor source concentration gradient has been investigated by a smart design of experiments. Silica nanostructure or their assemblies with different morphologies are obtained on photoresist-derived three-dimensional carbon microelectrode array. At a temperature of 1,000°C, rope-, feather-, and octopus-like nanowire assemblies can be obtained along with the Si vapor source concentration gradient flow. While at 950°C, stringlike assemblies, bamboo-like nanostructures with large joints, and hollow structures with smaller sizes can be obtained along with the Si vapor source concentration gradient flow. Both vapor-liquid-solid and vapor-quasiliquid-solid growth mechanisms have been applied to explain the diverse morphologies involving branching, connecting, and batch growth behaviors. The present approach offers a potential method for precise design and controlled synthesis of nanostructures with different features.

Reticulamoeba Is a Long-Branched Granofilosean (Cercozoa) That Is Missing from Sequence Databases

PubMed Central

Bass, David; Yabuki, Akinori; Santini, Sébastien; Romac, Sarah; Berney, Cédric

2012-01-01

We sequenced the 18S ribosomal RNA gene of seven isolates of the enigmatic marine amoeboflagellate Reticulamoeba Grell, which resolved into four genetically distinct Reticulamoeba lineages, two of which correspond to R. gemmipara Grell and R. minor Grell, another with a relatively large cell body forming lacunae, and another that has similarities to both R. minor and R. gemmipara but with a greater propensity to form cell clusters. These lineages together form a long-branched clade that branches within the cercozoan class Granofilosea (phylum Cercozoa), showing phylogenetic affinities with the genus Mesofila. The basic morphology of Reticulamoeba is a roundish or ovoid cell with a more or less irregular outline. Long and branched reticulopodia radiate from the cell. The reticulopodia bear granules that are bidirectionally motile. There is also a biflagellate dispersal stage. Reticulamoeba is frequently observed in coastal marine environmental samples. PCR primers specific to the Reticulamoeba clade confirm that it is a frequent member of benthic marine microbial communities, and is also found in brackish water sediments and freshwater biofilm. However, so far it has not been found in large molecular datasets such as the nucleotide database in NCBI GenBank, metagenomic datasets in Camera, and the marine microbial eukaryote sampling and sequencing consortium BioMarKs, although closely related lineages can be found in some of these datasets using a highly targeted approach. Therefore, although such datasets are very powerful tools in microbial ecology, they may, for several methodological reasons, fail to detect ecologically and evolutionary key lineages. PMID:23226495

Crack branching in cross-ply composites

NASA Astrophysics Data System (ADS)

La Saponara, Valeria

2001-10-01

The purpose of this research work is to examine the behavior of an interface crack in a cross-ply laminate which is subject to static and fatigue loading. The failure mechanism analyzed here is crack branching (or crack kinking or intra-layer crack): the delamination located between two different plies starts growing as an interface crack and then may branch into the less tough ply. The specimens were manufactured from different types of Glass/Epoxy and Graphite/Epoxy, by hand lay-up, vacuum bagging and cure in autoclave. Each specimen had a delamination starter. Static mixed mode tests and compressive fatigue tests were performed. Experiments showed the scale of the problem, one ply thickness, and some significant features, like contact in the branched crack. The amount of scatter in the experiments required use of statistics. Exploratory Data Analysis and a factorial design of experiments based on a 8 x 8 Hadamard matrix were used. Experiments and statistics show that there is a critical branching angle above which crack growth is greatly accelerated. This angle seems: (1) not to be affected by the specimens' life; (2) not to depend on the specimen geometry and loading conditions; (3) to strongly depend on the amount of contact in the branched crack. Numerical analysis was conducted to predict crack propagation based on the actual displacement/load curves for static tests. This method allows us to predict the total crack propagation in 2D conditions, while neglecting branching. Finally, the existence of a solution based on analytic continuation is discussed.

Mechanical Components Branch Test Facilities and Capabilities

NASA Technical Reports Server (NTRS)

Oswald, Fred B.

2004-01-01

The Mechanical Components Branch at NASA Glenn Research Center formulates, conducts, and manages research focused on propulsion systems for both present and advanced aeronautical and space vehicles. The branch is comprised of research teams that perform basic research in three areas: mechanical drives, aerospace seals, and space mechanisms. Each team has unique facilities for testing aerospace hardware and concepts. This report presents an overview of the Mechanical Components Branch test facilities.

BlastNeuron for Automated Comparison, Retrieval and Clustering of 3D Neuron Morphologies.

PubMed

Wan, Yinan; Long, Fuhui; Qu, Lei; Xiao, Hang; Hawrylycz, Michael; Myers, Eugene W; Peng, Hanchuan

2015-10-01

Characterizing the identity and types of neurons in the brain, as well as their associated function, requires a means of quantifying and comparing 3D neuron morphology. Presently, neuron comparison methods are based on statistics from neuronal morphology such as size and number of branches, which are not fully suitable for detecting local similarities and differences in the detailed structure. We developed BlastNeuron to compare neurons in terms of their global appearance, detailed arborization patterns, and topological similarity. BlastNeuron first compares and clusters 3D neuron reconstructions based on global morphology features and moment invariants, independent of their orientations, sizes, level of reconstruction and other variations. Subsequently, BlastNeuron performs local alignment between any pair of retrieved neurons via a tree-topology driven dynamic programming method. A 3D correspondence map can thus be generated at the resolution of single reconstruction nodes. We applied BlastNeuron to three datasets: (1) 10,000+ neuron reconstructions from a public morphology database, (2) 681 newly and manually reconstructed neurons, and (3) neurons reconstructions produced using several independent reconstruction methods. Our approach was able to accurately and efficiently retrieve morphologically and functionally similar neuron structures from large morphology database, identify the local common structures, and find clusters of neurons that share similarities in both morphology and molecular profiles.

Reperfusion of occluded branch retinal arteries by transluminal Nd:YAG laser embolysis combined with intravenous thrombolysis of urokinase

PubMed Central

Chai, Fang; Du, Shanshuang; Zhao, Xiquan

2017-01-01

Purpose: To report successful treatment with transluminal Nd:YAG laser embolysis (TYE) combined with urokinase thrombolysis for reperfusion of occluded branch retinal arteries with visible emboli. Methods: A total of 34 eyes from 34 patients with acute, severe vision loss secondary to a branch retinal artery occlusion with visible emboli and retinal whitening were examined. Each patient was administered TYE therapy, which focused on the embolus, using an ocular contact lens; a 0.3–0.9 mJ laser pulse was delivered directly and gradually according to the reaction. Fundus photographs and fundus fluorescein angiography (FFA) were obtained before and immediately after the laser treatment. All patients received urokinase thrombolysis therapy drops intravenously for 5 days at 10–20 u/d. The follow-up period ranged from 6 to 14 months after therapy. The morphological characteristics of FFA associated with obstruction recovery of arterial fluorescence filling and visual function were analyzed. Results: After TYE therapy, FFA examinations showed that the retinal artery and its branches exhibited completely restored blood flow without obstruction in 13 eyes, accounting for 38.2% of the cases. The blood flow was mostly recovered in 11 eyes (32.4% of patients). FFA examinations following the combined intravenous urokinase thrombolysis therapy showed that the retinal artery and its branches exhibited completely restored blood flow after obstruction in 16 eyes (47.1% of patients). The blood flow was mostly recovered in 15 eyes (44.1% of patients). Conclusion: TYE combined with urokinase thrombolysis is effective for reperfusion of occluded branch retinal arteries and improving visual recovery in patients with visible emboli. PMID:29162667

Widespread of horizontal gene transfer in the human genome.

PubMed

Huang, Wenze; Tsai, Lillian; Li, Yulong; Hua, Nan; Sun, Chen; Wei, Chaochun

2017-04-04

A fundamental concept in biology is that heritable material is passed from parents to offspring, a process called vertical gene transfer. An alternative mechanism of gene acquisition is through horizontal gene transfer (HGT), which involves movement of genetic materials between different species. Horizontal gene transfer has been found prevalent in prokaryotes but very rare in eukaryote. In this paper, we investigate horizontal gene transfer in the human genome. From the pair-wise alignments between human genome and 53 vertebrate genomes, 1,467 human genome regions (2.6 M bases) from all chromosomes were found to be more conserved with non-mammals than with most mammals. These human genome regions involve 642 known genes, which are enriched with ion binding. Compared to known horizontal gene transfer regions in the human genome, there were few overlapping regions, which indicated horizontal gene transfer is more common than we expected in the human genome. Horizontal gene transfer impacts hundreds of human genes and this study provided insight into potential mechanisms of HGT in the human genome.

Report of the Horizontal Launch Study

NASA Technical Reports Server (NTRS)

Wilhite, Alan W.; Bartolotta, Paul A.

2011-01-01

A study of horizontal launch concepts has been conducted. This study, jointly sponsored by the Defense Advanced Research Projects Agency (DARPA) and the National Aeronautics and Space Administration (NASA) was tasked to estimate the economic and technical viability of horizontal launch approaches. The study team identified the key parameters and critical technologies which determine mission viability and reported on the state of the art of critical technologies, along with objectives for technology development.

40 CFR 721.3627 - Branched synthetic fatty acid.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Branched synthetic fatty acid. 721... Substances § 721.3627 Branched synthetic fatty acid. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a branched synthetic fatty acid...

40 CFR 721.3627 - Branched synthetic fatty acid.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Branched synthetic fatty acid. 721... Substances § 721.3627 Branched synthetic fatty acid. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a branched synthetic fatty acid...

The influence of branch order on optimal leaf vein geometries: Murray's law and area preserving branching.

PubMed

Price, Charles A; Knox, Sarah-Jane C; Brodribb, Tim J

2013-01-01

Models that predict the form of hierarchical branching networks typically invoke optimization based on biomechanical similitude, the minimization of impedance to fluid flow, or construction costs. Unfortunately, due to the small size and high number of vein segments found in real biological networks, complete descriptions of networks needed to evaluate such models are rare. To help address this we report results from the analysis of the branching geometry of 349 leaf vein networks comprising over 1.5 million individual vein segments. In addition to measuring the diameters of individual veins before and after vein bifurcations, we also assign vein orders using the Horton-Strahler ordering algorithm adopted from the study of river networks. Our results demonstrate that across all leaves, both radius tapering and the ratio of daughter to parent branch areas for leaf veins are in strong agreement with the expectation from Murray's law. However, as veins become larger, area ratios shift systematically toward values expected under area-preserving branching. Our work supports the idea that leaf vein networks differentiate roles of leaf support and hydraulic supply between hierarchical orders.

Growth habit of the late Paleozoic rhizomorphic tree-lycopsid family Diaphorodendraceae: phylogenetic, evolutionary, and paleoecological significance.

PubMed

Dimichele, William A; Elrick, Scott D; Bateman, Richard M

2013-08-01

Rhizomorphic lycopsids evolved the tree habit independently of all other land plants. Newly discovered specimens allow radical revision of our understanding of the growth architectures of the extinct Paleozoic sister-genera Synchysidendron and Diaphorodendron. Detailed descriptions of six remarkable adpression specimens from the Pennsylvanian of the USA and three casts from the late Mississippian of Scotland are used to revise and reanalyze a previously published morphological cladistic matrix and to reinterpret their remarkable growth forms. Contrary to previous assertions, Synchysidendron resembled Diaphorodendron in having a distinct and relatively complex growth habit that emphasized serially homologous, closely spaced, deciduous lateral branches at the expense of reduced monocarpic crown branches. Lateral branches originated through several strongly anisotomous dichotomies before producing during extended periods large numbers of Achlamydocarpon strobili. The comparatively large diameter of abscission scars remaining on the main trunk and the emergence of branches above the horizontal plane suggest that the lateral branch systems were robust. Lateral branches were borne in two opposite rows on the main trunk and continued upward into an isotomously branched, determinate crown; their striking distichous arrangement caused preferred orientation of fallen trunks on bedding planes. This discovery identifies the plagiotropic growth habit, dominated by serial lateral branches, as ubiquitous in the Diaphorodendraceae and also as unequivocally primitive within Isoetales s.l., a conclusion supported by both the revised morphological cladistic analysis and relative first appearances of taxa in the fossil record. Previously assumed complete homology between crown branching in Lepidodendraceae and that of all earlier-divergent genera requires reassessment. Saltational phenotypic transitions via modification of key developmental switches remains the most credible

The effect of local hydrodynamics on the spatial extent and morphology of cold-water coral habitats at Tisler Reef, Norway

NASA Astrophysics Data System (ADS)

De Clippele, L. H.; Huvenne, V. A. I.; Orejas, C.; Lundälv, T.; Fox, A.; Hennige, S. J.; Roberts, J. M.

2018-03-01

This study demonstrates how cold-water coral morphology and habitat distribution are shaped by local hydrodynamics, using high-definition video from Tisler Reef, an inshore reef in Norway. A total of 334 video frames collected on the north-west (NW) and south-east (SE) side of the reef were investigated for Lophelia pertusa coral cover and morphology and for the cover of the associated sponges Mycale lingua and Geodia sp. Our results showed that the SE side was a better habitat for L. pertusa (including live and dead colonies). Low cover of Geodia sp. was found on both sides of Tisler Reef. In contrast, Mycale lingua had higher percentage cover, especially on the NW side of the reef. Bush-shaped colonies of L. pertusa with elongated branches were the most abundant coral morphology on Tisler Reef. The highest abundance and density of this morphology were found on the SE side of the reef, while a higher proportion of cauliflower-shaped corals with short branches were found on the NW side. The proportion of very small L. pertusa colonies was also significantly higher on the SE side of the reef. The patterns in coral spatial distribution and morphology were related to local hydrodynamics—there were more frequent periods of downwelling currents on the SE side—and to the availability of suitable settling substrates. These factors make the SE region of Tisler Reef more suitable for coral growth. Understanding the impact of local hydrodynamics on the spatial extent and morphology of coral, and their relation to associated organisms such as sponges, is key to understanding the past and future development of the reef.

Why mushrooms form gills: efficiency of the lamellate morphology.

PubMed

Fischer, Mark W F; Money, Nicholas P

2010-01-01

Gilled mushrooms are produced by multiple orders within the Agaricomycetes. Some species form a single array of unbranched radial gills beneath their caps, many others produce multiple files of lamellulae between the primary gills, and branched gills are also common. In this largely theoretical study we modeled the effects of different gill arrangements on the total surface area for spore production. Relative to spore production over a flat surface, gills achieve a maximum 20-fold increase in surface area. The branching of gills produces the same increase in surface area as the formation of free-standing lamellulae (short gills). The addition of lamellulae between every second gill would offer a slightly greater increase in surface area in comparison to the addition of lamellulae between every pair of opposing gills, but this morphology does not appear in nature. Analysis of photographs of mushrooms demonstrates an excellent match between natural gill arrangements and configurations predicted by our model. Copyright © 2009 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Cash efficiency for bank branches.

PubMed

Cabello, Julia García

2013-01-01

Bank liquidity management has become a major issue during the financial crisis as liquidity shortages have intensified and have put pressure on banks to diversity and improve their liquidity sources. While a significant strand of the literature concentrates on wholesale liquidity generation and on the alternative to deposit funding, the management of an inventory of cash holdings within the banks' branches is also a relevant issue as any significant improvement in cash management at the bank distribution channels may have a positive effect in reducing liquidity tensions. In this paper, we propose a simple programme of cash efficiency for the banks' branches, very easy to implement, which conform to a set of instructions to be imposed from the bank to their branches. This model proves to significantly reduce cash holdings at branches thereby providing efficiency improvements in liquidity management. The methodology we propose is based on the definition of some stochastic processes combined with renewal processes, which capture the random elements of the cash flow, before applying suitable optimization programmes to all the costs involved in cash movements. The classical issue of the Transaction Demand for the Cash and some aspects of Inventory Theory are also present. Mathematics Subject Classification (2000) C02, C60, E50.

30 CFR 57.6403 - Branch circuits.

Code of Federal Regulations, 2010 CFR

2010-07-01

... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Electric Blasting-Surface and Underground § 57.6403 Branch circuits. (a) If electric blasting includes the use of... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Branch circuits. 57.6403 Section 57.6403...

Space plasma branch at NRL

NASA Astrophysics Data System (ADS)

The Naval Research Laboratory (Washington, D.C.) formed the Space Plasma Branch within its Plasma Physics Division on July 1. Vithal Patel, former Program Director of Magnetospheric Physics, National Science Foundation, also joined NRL on the same date as Associate Superintendent of the Plasma Physics Division. Barret Ripin is head of the newly organized branch. The Space Plasma branch will do basic and applied space plasma research using a multidisciplinary approach. It consolidates traditional rocket and satellite space experiments, space plasma theory and computation, with laboratory space-related experiments. About 40 research scientists, postdoctoral fellows, engineers, and technicians are divided among its five sections. The Theory and Computation sections are led by Joseph Huba and Joel Fedder, the Space Experiments section is led by Paul Rodriguez, and the Pharos Laser Facility and Laser Experiments sections are headed by Charles Manka and Jacob Grun.

Building Virtual Spaces for Children in the Digital Branch

ERIC Educational Resources Information Center

DuBroy, Michelle

2010-01-01

Purpose: A digital branch is just like a physical branch except that content is delivered digitally via the web. A digital branch has staff, a collection, a community, and a building. The purpose of this paper is to explore the concept of building individual spaces for different user groups, specifically children, within a digital branch.…

12 CFR 208.6 - Establishment and maintenance of branches.

Code of Federal Regulations, 2011 CFR

2011-01-01

... the Board's Regulation K (12 CFR part 211). (3) Public notice of branch applications. (i) Location of... 12 Banks and Banking 2 2011-01-01 2011-01-01 false Establishment and maintenance of branches. 208... maintenance of national bank branches (12 U.S.C. 36 and 1831u), except that approval of such branches shall be...

Topological properties of the limited penetrable horizontal visibility graph family

NASA Astrophysics Data System (ADS)

Wang, Minggang; Vilela, André L. M.; Du, Ruijin; Zhao, Longfeng; Dong, Gaogao; Tian, Lixin; Stanley, H. Eugene

2018-05-01

The limited penetrable horizontal visibility graph algorithm was recently introduced to map time series in complex networks. In this work, we extend this algorithm to create a directed-limited penetrable horizontal visibility graph and an image-limited penetrable horizontal visibility graph. We define two algorithms and provide theoretical results on the topological properties of these graphs associated with different types of real-value series. We perform several numerical simulations to check the accuracy of our theoretical results. Finally, we present an application of the directed-limited penetrable horizontal visibility graph to measure real-value time series irreversibility and an application of the image-limited penetrable horizontal visibility graph that discriminates noise from chaos. We also propose a method to measure the systematic risk using the image-limited penetrable horizontal visibility graph, and the empirical results show the effectiveness of our proposed algorithms.

Evolution of Antifreeze Protein Genes in the Diatom Genus Fragilariopsis: Evidence for Horizontal Gene Transfer, Gene Duplication and Episodic Diversifying Selection

PubMed Central

Sorhannus, Ulf

2011-01-01

Hypotheses about horizontal transfer of antifreeze protein genes to ice-living diatoms were addressed using two different statistical methods available in the program Prunier. The role of diversifying selection in driving the differentiation of a set of antifreeze protein genes in the diatom genus Fragilariopsis was also investigated. Four horizontal gene transfer events were identified. Two of these took place between two major eukaryote lineages, that is from the diatom Chaetoceros neogracile to the copepod Stephos longipes and from a basidiomycete clade to a monophyletic group, consisting of the diatom species Fragilariopsis curta and Fragilariopsis cylindrus. The remaining two events included transfers from an ascomycete lineage to the proteobacterium Stigmatella aurantiaca and from the proteobacterium Polaribacter irgensii to a group composed of 4 proteobacterium species. After the Fragilariopsis lineage acquired the antifreeze protein gene from the basidiomycetes, it duplicated and went through episodic evolution, characterized by strong positive selection acting on short segments of the branches in the tree. This selection pattern suggests that the paralogs differentiated functionally over relatively short time periods. Taken together, the results obtained here indicate that the group of antifreeze protein genes considered here have a complex evolutionary history. PMID:22253534

Vere-Jones' self-similar branching model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saichev, A.; Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095; Sornette, D.

2005-11-01

Motivated by its potential application to earthquake statistics as well as for its intrinsic interest in the theory of branching processes, we study the exactly self-similar branching process introduced recently by Vere-Jones. This model extends the ETAS class of conditional self-excited branching point-processes of triggered seismicity by removing the problematic need for a minimum (as well as maximum) earthquake size. To make the theory convergent without the need for the usual ultraviolet and infrared cutoffs, the distribution of magnitudes m{sup '} of daughters of first-generation of a mother of magnitude m has two branches m{sup '}m with exponent {beta}+d, where {beta} and d are two positive parameters. We investigate the condition and nature of the subcritical, critical, and supercritical regime in this and in an extended version interpolating smoothly between several models. We predict that the distribution of magnitudes of events triggered by a mother of magnitude m over all generations has also two branches m{sup '}m with exponent {beta}+h, with h=d{radical}(1-s), where s is the fraction of triggered events. This corresponds to a renormalization of the exponent d into h by the hierarchy of successive generations of triggered events. For a significant part of the parameter space, the distribution of magnitudes over a full catalog summed over an average steady flow of spontaneous sources (immigrants) reproduces the distribution of the spontaneous sources with a single branch and is blind to the exponents {beta},d of the distribution of triggered events. Since the distribution of earthquake magnitudes is usually obtained with catalogs including many sequences, we conclude that the two branches of the distribution of aftershocks are not directly observable and the model is compatible with real seismic catalogs. In summary, the exactly self-similar Vere-Jones model provides an

Accommodation measurements of horizontally scanning holographic display.

PubMed

Takaki, Yasuhiro; Yokouchi, Masahito

2012-02-13

Eye accommodation is considered to function properly for three-dimensional (3D) images generated by holography. We developed a horizontally scanning holographic display technique that enlarges both the screen size and viewing zone angle. A 3D image generated by this technique can be easily seen by both eyes. In this study, we measured the accommodation responses to a 3D image generated by the horizontally scanning holographic display technique that has a horizontal viewing zone angle of 14.6° and screen size of 4.3 in. We found that the accommodation responses to a 3D image displayed within 400 mm from the display screen were similar to those of a real object.

[Vascular lesions of vocal folds--part 1: horizontal vascular lesions].

PubMed

Voigt-Zimmermann, S; Arens, C

2014-12-01

In recent decades, the endoscopic methods and technologies for laryngeal examination have improved so much that not only epithelial changes, but also vascular changes are recognizable at earlier stages. When comparing newer and older literature, the associated increasingly differentiated descriptions of such visible vascular changes of the vocal folds lead to terminological blurring and shifts of meaning. This complicates the technical-scientific discourse. The aim of the present work is a theoretical and conceptual clarification of early vascular changes of vocal folds. Horizontal changes of benigne vascular diseases, e. g. vessel ectasia, meander, increasing number and branching of vessels, change of direction may develop in to manifest vascular lesions, like varicosis, polyps and in case of ruptures to haemorrhages of vocal folds. These beginning and reversible vascular changes, when early detected and discussed basing on etiological knowledge, may lead to more differentiated prognostic statements and adequate therapeutic decisions, e. g. phonosurgery, functional voice therapy, voice hygiene and voice rest. Vertical vascular changes, like vessel loops, occur primarily in laryngeal papilloma, pre-cancerous and cancerous changes of the vocal folds. Already in small cancerous lesions of the vocal folds the vascular architecture is completely destroyed. © Georg Thieme Verlag KG Stuttgart · New York.

Functional traits and root morphology of alpine plants

PubMed Central

Pohl, Mandy; Stroude, Raphaël; Buttler, Alexandre; Rixen, Christian

2011-01-01

Background and Aims Vegetation has long been recognized to protect the soil from erosion. Understanding species differences in root morphology and functional traits is an important step to assess which species and species mixtures may provide erosion control. Furthermore, extending classification of plant functional types towards root traits may be a useful procedure in understanding important root functions. Methods In this study, pioneer data on traits of alpine plant species, i.e. plant height and shoot biomass, root depth, horizontal root spreading, root length, diameter, tensile strength, plant age and root biomass, from a disturbed site in the Swiss Alps are presented. The applicability of three classifications of plant functional types (PFTs), i.e. life form, growth form and root type, was examined for above- and below-ground plant traits. Key Results Plant traits differed considerably among species even of the same life form, e.g. in the case of total root length by more than two orders of magnitude. Within the same root diameter, species differed significantly in tensile strength: some species (Geum reptans and Luzula spicata) had roots more than twice as strong as those of other species. Species of different life forms provided different root functions (e.g. root depth and horizontal root spreading) that may be important for soil physical processes. All classifications of PFTs were helpful to categorize plant traits; however, the PFTs according to root type explained total root length far better than the other PFTs. Conclusions The results of the study illustrate the remarkable differences between root traits of alpine plants, some of which cannot be assessed from simple morphological inspection, e.g. tensile strength. PFT classification based on root traits seems useful to categorize plant traits, even though some patterns are better explained at the individual species level. PMID:21795278

Investigation of Retinal Morphology Alterations Using Spectral Domain Optical Coherence Tomography in a Mouse Model of Retinal Branch and Central Retinal Vein Occlusion

PubMed Central

Ebneter, Andreas; Agca, Cavit; Dysli, Chantal; Zinkernagel, Martin S.

2015-01-01

Retinal vein occlusion is a leading cause of visual impairment. Experimental models of this condition based on laser photocoagulation of retinal veins have been described and extensively exploited in mammals and larger rodents such as the rat. However, few reports exist on the use of this paradigm in the mouse. The objective of this study was to investigate a model of branch and central retinal vein occlusion in the mouse and characterize in vivo longitudinal retinal morphology alterations using spectral domain optical coherence tomography. Retinal veins were experimentally occluded using laser photocoagulation after intravenous application of Rose Bengal, a photo-activator dye enhancing thrombus formation. Depending on the number of veins occluded, variable amounts of capillary dropout were seen on fluorescein angiography. Vascular endothelial growth factor levels were markedly elevated early and peaked at day one. Retinal thickness measurements with spectral domain optical coherence tomography showed significant swelling (p<0.001) compared to baseline, followed by gradual thinning plateauing two weeks after the experimental intervention (p<0.001). Histological findings at day seven correlated with spectral domain optical coherence tomography imaging. The inner layers were predominantly affected by degeneration with the outer nuclear layer and the photoreceptor outer segments largely preserved. The application of this retinal vein occlusion model in the mouse carries several advantages over its use in other larger species, such as access to a vast range of genetically modified animals. Retinal changes after experimental retinal vein occlusion in this mouse model can be non-invasively quantified by spectral domain optical coherence tomography, and may be used to monitor effects of potential therapeutic interventions. PMID:25775456

The sensory-motor bridge neurorraphy: an anatomic study of feasibility between sensory branch of the musculocutaneous nerve and deep branch of the radial nerve.

PubMed

Goubier, Jean-Noel; Teboul, Frédéric

2011-05-01

Restoring elbow flexion remains the first step in the management of total palsy of the brachial plexus. Non avulsed upper roots may be grafted on the musculocutaneous nerve. When this nerve is entirely grafted, some motor fibres regenerate within the sensory fibres quota. Aiming potential utilization of these lost motor fibres, we attempted suturing the sensory branch of the musculocutaneous nerve onto the deep branch of the radial nerve. The objective of our study was to assess the anatomic feasibility of such direct suturing of the terminal sensory branch of the musculocutaneous nerve onto the deep branch of the radial nerve. The study was carried out with 10 upper limbs from fresh cadavers. The sensory branch of the musculocutaneous muscle was dissected right to its division. The motor branch of the radial nerve was identified and dissected as proximally as possible into the radial nerve. Then, the distance separating the two nerves was measured so as to assess whether direct neurorraphy of the two branches was feasible. The excessive distance between the two branches averaged 6 mm (1-13 mm). Thus, direct neurorraphy of the sensory branch of the musculocutaneous nerve and the deep branch of the radial nerve was possible. When the whole musculocutaneous nerve is grafted, some of its motor fibres are lost amongst the sensory fibres (cutaneous lateral antebrachial nerve). By suturing this sensory branch onto the deep branch of the radial nerve, "lost" fibres may be retrieved, resulting in restoration of digital extension. Copyright © 2011 Wiley-Liss, Inc.

Branch breakage under snow and ice loads.

PubMed

Cannell, M G; Morgan, J

1989-09-01

Measurements were made on branches and trunks of Picea sitchensis (Bong.) Carr. to determine the relationship between (i) the bending moment at the bases of branches that cause breakage, and (ii) midpoint diameter cubed. The theory for cantilever beams was then used to calculate the basal bending moments and midpoint diameters of branches with different numbers of laterals and endpoint deflections, given previously measured values of Young's modulus, taper and weights of foliage and wood. Snow and ice loads (equal to 2 and 4 g cm(-1) of shoot, respectively) were then included in the calculation to determine whether the basal bending moments exceeded the breakage values. The likelihood of breakage increased with an increase in (i) number of laterals, and (ii) endpoint deflection under self weight (without snow or ice)-features that had previously been shown to lessen the amount of branch wood required to support a unit of foliage. However, branches which deflected moderately (> 10% of their length) under their own weight deflected greatly under snow or ice loads and might shed powdery snow before breakage occurs.

Cleanup/stimulation of a horizontal wellbore using propellants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rougeot, J.E.; Lauterbach, K.A.

1993-01-01

This report documents the stimulation/cleanup of a horizontal well bore (Wilson 25) using propellants. The Wilson 25 is a Bartlesville Sand well located in the Flatrock Field, Osage County, Oklahoma. The Wilson 25 was drilled to determine if horizontal drilling could be used as a means to economically recover primary oil that had been left in place in a mostly abandoned oil field because of the adverse effects of water coning. Pump testing of the Wilson 25 horizontal well bore before cleanup or stimulation produced 6 barrels of oil and .84 barrels of water per day. The high percentage ofmore » daily oil production to total daily fluid production indicated that the horizontal well bore had accessed potentially economical oil reserves if the fluid production rate could be increased by performing a cleanup/stimulation treatment. Propellants were selected as an inexpensive means to stimulate and cleanup the near well bore area in a uniform manner. The ignition of a propellant creates a large volume of gas which penetrates the formation, creating numerous short cracks through which hydrocarbons can travel into the well bore. More conventional stimulation/cleanup techniques were either significantly more expensive, less likely to treat uniformly, or could not be confined to the near well bore area. Three different propellant torpedo designs were tested with a total of 304' of horizontal well bore being shot and producible. The initial test shot caused 400' of the horizontal well bore to become plugged off, and subsequently it could not be production tested. The second and third test shots were production tested, with the oil production being increased 458% and 349%, respectively, on a per foot basis. The Wilson 25 results indicate that a propellant shot treatment is an economically viable means to cleanup/stimulate a horizontal well bore.« less

International transferability of accident modification functions for horizontal curves.

PubMed

Elvik, Rune

2013-10-01

Studies of the relationship between characteristics of horizontal curves and accident rate have been reported in several countries. The characteristic most often studied is the radius of a horizontal curve. Functions describing the relationship between the radius of horizontal curves and accident rate have been developed in Australia, Canada, Denmark, Germany, Great Britain, New Zealand, Norway, Portugal, Sweden, and the United States. Other characteristics of horizontal curves that have been studied include deflection angle, curve length, the presence of transition curves, super-elevation in curves and distance to adjacent curves. This paper assesses the international transferability of mathematical functions (accident modification functions) that have been developed to relate the radius of horizontal curves to their accident rate. The main research problem is whether these functions are similar, which enhances international transferability, or dissimilar, which reduces international transferability. Accident modification functions for horizontal curve radius developed in the countries listed above are synthesised. The sensitivity of the functions to other characteristics of curves than radius is examined. Accident modification functions developed in different countries have important similarities. The functions diverge with respect to accident rate in the sharpest curves. Copyright © 2013 Elsevier Ltd. All rights reserved.

Carlactone-type strigolactones and their synthetic analogues as inducers of hyphal branching in arbuscular mycorrhizal fungi.

PubMed

Mori, Narumi; Nishiuma, Kenta; Sugiyama, Takuya; Hayashi, Hideo; Akiyama, Kohki

2016-10-01

Hyphal branching in the vicinity of host roots is a host recognition response of arbuscular mycorrhizal fungi. This morphological event is elicited by strigolactones. Strigolactones are carotenoid-derived terpenoids that are synthesized from carlactone and its oxidized derivatives. To test the possibility that carlactone and its oxidized derivatives might act as host-derived precolonization signals in arbuscular mycorrhizal symbiosis, carlactone, carlactonoic acid, and methyl carlactonoate as well as monohydroxycarlactones, 4-, 18-, and 19-hydroxycarlactones, were synthesized chemically and evaluated for hyphal branching-inducing activity in germinating spores of the arbuscular mycorrhizal fungus Gigaspora margarita. Hyphal branching activity was found to correlate with the degree of oxidation at C-19 methyl. Carlactone was only weakly active (100 ng/disc), whereas carlactonoic acid showed comparable activity to the natural canonical strigolactones such as strigol and sorgomol (100 pg/disc). Hydroxylation at either C-4 or C-18 did not significantly affect the activity. A series of carlactone analogues, named AD ester and AA'D diester, was synthesized by reacting formyl Meldrum's acid with benzyl, cyclohexylmethyl, and cyclogeranyl alcohols (the A-ring part), followed by coupling of the potassium enolates of the resulting formylacetic esters with the D-ring butenolide. AD ester analogues exhibited moderate activity (1 ng-100 pg/disc), while AA'D diester analogues having cyclohexylmethyl and cyclogeranyl groups were highly active on the AM fungus (10 pg/disc). These results indicate that the oxidation of methyl to carboxyl at C-19 in carlactone is a prerequisite but BC-ring formation is not essential to show hyphal branching activity comparable to that of canonical strigolactones. Copyright © 2016 Elsevier Ltd. All rights reserved.

Root Type-Specific Reprogramming of Maize Pericycle Transcriptomes by Local High Nitrate Results in Disparate Lateral Root Branching Patterns1[OPEN

PubMed Central

Lithio, Andrew

2016-01-01

The adaptability of root system architecture to unevenly distributed mineral nutrients in soil is a key determinant of plant performance. The molecular mechanisms underlying nitrate dependent plasticity of lateral root branching across the different root types of maize are only poorly understood. In this study, detailed morphological and anatomical analyses together with cell type-specific transcriptome profiling experiments combining laser capture microdissection with RNA-seq were performed to unravel the molecular signatures of lateral root formation in primary, seminal, crown, and brace roots of maize (Zea mays) upon local high nitrate stimulation. The four maize root types displayed divergent branching patterns of lateral roots upon local high nitrate stimulation. In particular, brace roots displayed an exceptional architectural plasticity compared to other root types. Transcriptome profiling revealed root type-specific transcriptomic reprogramming of pericycle cells upon local high nitrate stimulation. The alteration of the transcriptomic landscape of brace root pericycle cells in response to local high nitrate stimulation was most significant. Root type-specific transcriptome diversity in response to local high nitrate highlighted differences in the functional adaptability and systemic shoot nitrogen starvation response during development. Integration of morphological, anatomical, and transcriptomic data resulted in a framework underscoring similarity and diversity among root types grown in heterogeneous nitrate environments. PMID:26811190

Branching processes in disease epidemics

NASA Astrophysics Data System (ADS)

Singh, Sarabjeet

Branching processes have served as a model for chemical reactions, biological growth processes and contagion (of disease, information or fads). Through this connection, these seemingly different physical processes share some common universalities that can be elucidated by analyzing the underlying branching process. In this thesis, we focus on branching processes as a model for infectious diseases spreading between individuals belonging to different populations. The distinction between populations can arise from species separation (as in the case of diseases which jump across species) or spatial separation (as in the case of disease spreading between farms, cities, urban centers, etc). A prominent example of the former is zoonoses -- infectious diseases that spill from animals to humans -- whose specific examples include Nipah virus, monkeypox, HIV and avian influenza. A prominent example of the latter is infectious diseases of animals such as foot and mouth disease and bovine tuberculosis that spread between farms or cattle herds. Another example of the latter is infectious diseases of humans such as H1N1 that spread from one city to another through migration of infectious hosts. This thesis consists of three main chapters, an introduction and an appendix. The introduction gives a brief history of mathematics in modeling the spread of infectious diseases along with a detailed description of the most commonly used disease model -- the Susceptible-Infectious-Recovered (SIR) model. The introduction also describes how the stochastic formulation of the model reduces to a branching process in the limit of large population which is analyzed in detail. The second chapter describes a two species model of zoonoses with coupled SIR processes and proceeds into the calculation of statistics pertinent to cross species infection using multitype branching processes. The third chapter describes an SIR process driven by a Poisson process of infection spillovers. This is posed as a

Perceptions of horizontal violence in staff nurses and intent to leave.

PubMed

Armmer, Francesca; Ball, Charlotte

2015-01-01

The impact of horizontal violence is multifaceted. From the impact upon the individual, the unit, and the institution, horizontal violence affects professional nursing activities in a variety of aspects of health care. To examine registered nurses' experiences with horizontal violence and explore the relationship between horizontal violence and intent to leave. A random sample of 300 registered nurses from a Midwestern hospital received the Briles' Sabotage Savvy Questionnaire (BSSQ), the Michigan Organizational Assessment Questionnaire (MOAQ) Intent to Turnover measure, and a Demographic questionnaire. Descriptive correlational study was implemented. Questionnaires were distributed to the selected registered nurses. Descriptive and correlational statistics were calculated. Horizontal violence had been experienced by nurses of all ages and experience. Based upon measurement tools, examples of horizontal violence were: Being held responsible for coworkers' duties; Reprimanded or confronted in front of others; Failure to be acknowledged or confronted in front of others; and Untrue information about you being passed or exchanged. Correlations indicated a significant, positive relationship between perceptions of horizontal violence and intent to leave. Results also indicated the longer nurses were employed the more likely to perceive themselves as victims of horizontal violence. Additionally, results associated with the MOAQ, age and years employed indicated that older nurses and those with increasing years of employment were less likely to leave. Younger nurses indicated more willingness to leave a position due to perceived horizontal violence than older nurses. Activities to address the impact of perceived horizontal violence are needed. Workplace strategies may include mentoring, ongoing assessment of organizational climate, and zero tolerance for horizontal violence.

7 CFR 51.573 - Damage.

Code of Federal Regulations, 2014 CFR

2014-01-01

... the maximum allowed for any one defect, shall be considered as damage: (a) Growth cracks when more than 2 branches are affected by growth cracks which are over one-half inch in length, or when more than 6 branches have growth cracks; (b) Horizontal cracks when more than 3 branches have horizontal...

7 CFR 51.573 - Damage.

Code of Federal Regulations, 2013 CFR

2013-01-01

... the maximum allowed for any one defect, shall be considered as damage: (a) Growth cracks when more than 2 branches are affected by growth cracks which are over one-half inch in length, or when more than 6 branches have growth cracks; (b) Horizontal cracks when more than 3 branches have horizontal...

26 CFR 1.884-1 - Branch profits tax.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 26 Internal Revenue 9 2013-04-01 2013-04-01 false Branch profits tax. 1.884-1 Section 1.884-1...) INCOME TAXES (CONTINUED) Foreign Corporations § 1.884-1 Branch profits tax. (a) General rule. A foreign corporation shall be liable for a branch profits tax in an amount equal to 30 percent of the foreign...

26 CFR 1.884-1 - Branch profits tax.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 26 Internal Revenue 9 2014-04-01 2014-04-01 false Branch profits tax. 1.884-1 Section 1.884-1...) INCOME TAXES (CONTINUED) Foreign Corporations § 1.884-1 Branch profits tax. (a) General rule. A foreign corporation shall be liable for a branch profits tax in an amount equal to 30 percent of the foreign...

26 CFR 1.884-1 - Branch profits tax.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 26 Internal Revenue 9 2012-04-01 2012-04-01 false Branch profits tax. 1.884-1 Section 1.884-1...) INCOME TAXES (CONTINUED) Foreign Corporations § 1.884-1 Branch profits tax. (a) General rule. A foreign corporation shall be liable for a branch profits tax in an amount equal to 30 percent of the foreign...

Epicormic Branches and Lumber Grade of Bottomland Oak

Treesearch

James S. Meadows

1995-01-01

Epicormic branches can be a serious problem in management of hardwood forests for high-quality sawtimber production. In one study in central Alabama, defects caused by epicormic branches that developed following a partial cutting resulted in a 13 percent reduction in the value of willow oak lumber. Production of epicormic branches along the boles of hardwood trees is...

Statistical analysis and data mining of digital reconstructions of dendritic morphologies.

PubMed

Polavaram, Sridevi; Gillette, Todd A; Parekh, Ruchi; Ascoli, Giorgio A

2014-01-01

Neuronal morphology is diverse among animal species, developmental stages, brain regions, and cell types. The geometry of individual neurons also varies substantially even within the same cell class. Moreover, specific histological, imaging, and reconstruction methodologies can differentially affect morphometric measures. The quantitative characterization of neuronal arbors is necessary for in-depth understanding of the structure-function relationship in nervous systems. The large collection of community-contributed digitally reconstructed neurons available at NeuroMorpho.Org constitutes a "big data" research opportunity for neuroscience discovery beyond the approaches typically pursued in single laboratories. To illustrate these potential and related challenges, we present a database-wide statistical analysis of dendritic arbors enabling the quantification of major morphological similarities and differences across broadly adopted metadata categories. Furthermore, we adopt a complementary unsupervised approach based on clustering and dimensionality reduction to identify the main morphological parameters leading to the most statistically informative structural classification. We find that specific combinations of measures related to branching density, overall size, tortuosity, bifurcation angles, arbor flatness, and topological asymmetry can capture anatomically and functionally relevant features of dendritic trees. The reported results only represent a small fraction of the relationships available for data exploration and hypothesis testing enabled by sharing of digital morphological reconstructions.

Horizontal violence in nursing: the continuing silence.

PubMed

McCall, E

1996-04-01

Horizontal violence continues to affect the lives of many nurses today. This paper will present the findings of research which utilised a feminist methodology to document the stories of nurses illustrating their experiences of horizontal violence in their workplaces, and their perceptions of the reasons for the continued oppression of nurses, despite almost fifteen years of academic writing on the subject.

Horizontal electric fields from lightning return strokes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomson, E.M.; Uman, M.A.; Johnson, J.

1985-01-01

Measurements are presented of simultaneous horizontal and vertical electric fields from both close and distant lightning return strokes. The data were obtained during summer 1984 at the Kennedy Space Center, Florida, using an electrically isolated spherical antenna having a system bandwidth of 3 Hz to 5 MHz. Lightning signals were obtained from flashes at distances from a few to 100 kilometers. Since the horizontal electric field is in part determined by the local ground conductivity, that parameter was measured as a function of depth. The horizontal fields from lightning return strokes had typically 1/50 the peak amplitude of the verticalmore » fields and waveshapes which were consistant with available theory, as expressed by the ''wavetilt'' formula.« less

Steerable vertical to horizontal energy transducer for mobile robots

DOEpatents

Spletzer, Barry L.; Fischer, Gary J.; Feddema, John T.

2001-01-01

The present invention provides a steerable vertical to horizontal energy transducer for mobile robots that less complex and requires less power than two degree of freedom tilt mechanisms. The present invention comprises an end effector that, when mounted with a hopping actuator, translates along axis (typically vertical) actuation into combined vertical and horizontal motion. The end effector, or foot, mounts with an end of the actuator that moves toward the support surface (typically a floor or the earth). The foot is shaped so that the first contact with the support surface is off the axis of the actuator. Off-axis contact with the support surface generates an on-axis force (typically resulting in vertical motion) and a moment orthogonal to the axis. The moment initiates a horizontal tumbling motion, and tilts the actuator so that its axis is oriented with a horizontal component and continued actuation generates both vertical and horizontal force.

Segmentation of the Aortic Valve Apparatus in 3D Echocardiographic Images: Deformable Modeling of a Branching Medial Structure

PubMed Central

Pouch, Alison M.; Tian, Sijie; Takabe, Manabu; Wang, Hongzhi; Yuan, Jiefu; Cheung, Albert T.; Jackson, Benjamin M.; Gorman, Joseph H.; Gorman, Robert C.; Yushkevich, Paul A.

2015-01-01

3D echocardiographic (3DE) imaging is a useful tool for assessing the complex geometry of the aortic valve apparatus. Segmentation of this structure in 3DE images is a challenging task that benefits from shape-guided deformable modeling methods, which enable inter-subject statistical shape comparison. Prior work demonstrates the efficacy of using continuous medial representation (cm-rep) as a shape descriptor for valve leaflets. However, its application to the entire aortic valve apparatus is limited since the structure has a branching medial geometry that cannot be explicitly parameterized in the original cm-rep framework. In this work, we show that the aortic valve apparatus can be accurately segmented using a new branching medial modeling paradigm. The segmentation method achieves a mean boundary displacement of 0.6 ± 0.1 mm (approximately one voxel) relative to manual segmentation on 11 3DE images of normal open aortic valves. This study demonstrates a promising approach for quantitative 3DE analysis of aortic valve morphology. PMID:26247062

Effects of an Isolated Complete Right Bundle Branch Block on Mechanical Ventricular Function.

PubMed

Zhang, Qin; Xue, Minghua; Li, Zhan; Wang, Haiyan; Zhu, Lei; Liu, Xinling; Meng, Haiyan; Hou, Yinglong

2015-12-01

The purpose of this study was to investigate the effects of an isolated complete right bundle branch block on mechanical ventricular function. Two groups of participants were enrolled in this study: a block group, consisting of 98 patients with isolated complete right bundle branch blocks without structural heart disease, and a control group, consisting of 92 healthy adults. The diameter, end-diastolic area, end-systolic area, and right ventricular (RV) fractional area change were obtained to evaluate morphologic and systolic function by 2-dimensional sonographic technology. Systolic and diastolic velocities and time interval parameters were measured to assess mechanical ventricular performance using pulsed wave tissue Doppler imaging. Although there was no significant difference in the RV fractional area change between the patients with blocks and controls, the diameter, end-diastolic area, and end-systolic area of the RV were significantly larger in the patients with blocks (P < .05). In the patients with blocks, the peak velocities during systole and early diastole and the ratio of the peak velocities during early and late diastole decreased. The block group had a prolonged pre-ejection period, electromechanical delay time, and isovolumic relaxation time, a decreased ejection time, and an increased pre-ejection period/ejection time ratio, and the myocardial performance index (Tei index) at the basal RV lateral wall was significantly increased. There were no significant differences in any echocardiographic parameters at different sites of the left ventricle. In patients with isolated complete right bundle branch blocks, systolic and diastolic functions are impaired in the RV, and follow-up is needed. © 2015 by the American Institute of Ultrasound in Medicine.

Orienting numbers in mental space: horizontal organization trumps vertical.

PubMed

Holmes, Kevin J; Lourenco, Stella F

2012-01-01

While research on the spatial representation of number has provided substantial evidence for a horizontally oriented mental number line, recent studies suggest vertical organization as well. Directly comparing the relative strength of horizontal and vertical organization, however, we found no evidence of spontaneous vertical orientation (upward or downward), and horizontal trumped vertical when pitted against each other (Experiment 1). Only when numbers were conceptualized as magnitudes (as opposed to nonmagnitude ordinal sequences) did reliable vertical organization emerge, with upward orientation preferred (Experiment 2). Altogether, these findings suggest that horizontal representations predominate, and that vertical representations, when elicited, may be relatively inflexible. Implications for spatial organization beyond number, and its ontogenetic basis, are discussed.

Different evolutionary pathways underlie the morphology of wrist bones in hominoids

PubMed Central

2013-01-01

Background The hominoid wrist has been a focus of numerous morphological analyses that aim to better understand long-standing questions about the evolution of human and hominoid hand use. However, these same analyses also suggest various scenarios of complex and mosaic patterns of morphological evolution within the wrist and potentially multiple instances of homoplasy that would benefit from require formal analysis within a phylogenetic context. We identify morphological features that principally characterize primate – and, in particular, hominoid (apes, including humans) - wrist evolution and reveal the rate, process and evolutionary timing of patterns of morphological change on individual branches of the primate tree of life. Linear morphological variables of five wrist bones – the scaphoid, lunate, triquetrum, capitate and hamate – are analyzed in a diverse sample of extant hominoids (12 species, 332 specimens), Old World (8 species, 43 specimens) and New World (4 species, 26 specimens) monkeys, fossil Miocene apes (8 species, 20 specimens) and Plio-Pleistocene hominins (8 species, 18 specimens). Result Results reveal a combination of parallel and synapomorphic morphology within haplorrhines, and especially within hominoids, across individual wrist bones. Similar morphology of some wrist bones reflects locomotor behaviour shared between clades (scaphoid, triquetrum and capitate) while others (lunate and hamate) indicate clade-specific synapomorphic morphology. Overall, hominoids show increased variation in wrist bone morphology compared with other primate clades, supporting previous analyses, and demonstrate several occurrences of parallel evolution, particularly between orangutans and hylobatids, and among hominines (extant African apes, humans and fossil hominins). Conclusions Our analyses indicate that different evolutionary processes can underlie the evolution of a single anatomical unit (the wrist) to produce diversity in functional and morphological

Cadaveric Study of the Articular Branches of the Shoulder Joint.

PubMed

Eckmann, Maxim S; Bickelhaupt, Brittany; Fehl, Jacob; Benfield, Jonathan A; Curley, Jonathan; Rahimi, Ohmid; Nagpal, Ameet S

This cadaveric study investigated the anatomic relationships of the articular branches of the suprascapular (SN), axillary (AN), and lateral pectoral nerves (LPN), which are potential targets for shoulder analgesia. Sixteen embalmed cadavers and 1 unembalmed cadaver, including 33 shoulders total, were dissected. Following dissections, fluoroscopic images were taken to propose an anatomical landmark to be used in shoulder articular branch blockade. Thirty-three shoulders from 17 total cadavers were studied. In a series of 16 shoulders, 16 (100%) of 16 had an intact SN branch innervating the posterior head of the humerus and shoulder capsule. Suprascapular sensory branches coursed laterally from the spinoglenoid notch then toward the glenohumeral joint capsule posteriorly. Axillary nerve articular branches innervated the posterolateral head of the humerus and shoulder capsule in the same 16 (100%) of 16 shoulders. The AN gave branches ascending circumferentially from the quadrangular space to the posterolateral humerus, deep to the deltoid, and inserting at the inferior portion of the posterior joint capsule. In 4 previously dissected and 17 distinct shoulders, intact LPNs could be identified in 14 (67%) of 21 specimens. Of these, 12 (86%) of 14 had articular branches innervating the anterior shoulder joint, and 14 (100%) of 14 LPN articular branches were adjacent to acromial branches of the thoracoacromial blood vessels over the superior aspect of the coracoid process. Articular branches from the SN, AN, and LPN were identified. Articular branches of the SN and AN insert into the capsule overlying the glenohumeral joint posteriorly. Articular branches of the LPN exist and innervate a portion of the anterior shoulder joint.

Finding the optimal lengths for three branches at a junction.

PubMed

Woldenberg, M J; Horsfield, K

1983-09-21

This paper presents an exact analytical solution to the problem of locating the junction point between three branches so that the sum of the total costs of the branches is minimized. When the cost per unit length of each branch is known the angles between each pair of branches can be deduced following reasoning first introduced to biology by Murray. Assuming the outer ends of each branch are fixed, the location of the junction and the length of each branch are then deduced using plane geometry and trigonometry. The model has applications in determining the optimal cost of a branch or branches at a junction. Comparing the optimal to the actual cost of a junction is a new way to compare cost models for goodness of fit to actual junction geometry. It is an unambiguous measure and is superior to comparing observed and optimal angles between each daughter and the parent branch. We present data for 199 junctions in the pulmonary arteries of two human lungs. For the branches at each junction we calculated the best fitting value of x from the relationship that flow alpha (radius)x. We found that the value of x determined whether a junction was best fitted by a surface, volume, drag or power minimization model. While economy of explanation casts doubt that four models operate simultaneously, we found that optimality may still operate, since the angle to the major daughter is less than the angle to the minor daughter. Perhaps optimality combined with a space filling branching pattern governs the branching geometry of the pulmonary artery.

Phylogenetic studies favour the unification of Pennisetum, Cenchrus and Odontelytrum (Poaceae): a combined nuclear, plastid and morphological analysis, and nomenclatural combinations in Cenchrus.

PubMed

Chemisquy, M Amelia; Giussani, Liliana M; Scataglini, María A; Kellogg, Elizabeth A; Morrone, Osvaldo

2010-07-01

Twenty-five genera having sterile inflorescence branches were recognized as the bristle clade within the x = 9 Paniceae (Panicoideae). Within the bristle clade, taxonomic circumscription of Cenchrus (20-25 species), Pennisetum (80-140) and the monotypic Odontelytrum is still unclear. Several criteria have been applied to characterize Cenchrus and Pennisetum, but none of these has proved satisfactory as the diagnostic characters, such as fusion of bristles in the inflorescences, show continuous variation. A phylogenetic analysis based on morphological, plastid (trnL-F, ndhF) and nuclear (knotted) data is presented for a representative species sampling of the genera. All analyses were conducted under parsimony, using heuristic searches with TBR branch swapping. Branch support was assessed with parsimony jackknifing. Based on plastid and morphological data, Pennisetum, Cenchrus and Odontelytrum were supported as a monophyletic group: the PCO clade. Only one section of Pennisetum (Brevivalvula) was supported as monophyletic. The position of P. lanatum differed among data partitions, although the combined plastid and morphology and nuclear analyses showed this species to be a member of the PCO clade. The basic chromosome number x = 9 was found to be plesiomorphic, and x = 5, 7, 8, 10 and 17 were derived states. The nuclear phylogenetic analysis revealed a reticulate pattern of relationships among Pennisetum and Cenchrus, suggesting that there are at least three different genomes. Because apomixis can be transferred among species through hybridization, its history most likely reflects crossing relationships, rather than multiple independent appearances. Due to the consistency between the present results and different phylogenetic hypotheses (including morphological, developmental and multilocus approaches), and the high support found for the PCO clade, also including the type species of the three genera, we propose unification of Pennisetum, Cenchrus and Odontelytrum

Variations in cell morphology in the canine cruciate ligament complex.

PubMed

Smith, K D; Vaughan-Thomas, A; Spiller, D G; Clegg, P D; Innes, J F; Comerford, E J

2012-08-01

Cell morphology may reflect the mechanical environment of tissues and influence tissue physiology and response to injury. Normal cruciate ligaments (CLs) from disease-free stifle joints were harvested from dog breeds with a high (Labrador retriever) and low (Greyhound) risk of cranial cruciate ligament (CCL) rupture. Antibodies against the cytoskeletal components vimentin and alpha tubulin were used to analyse cell morphology; nuclei were stained with 4',6-diamidino-2-phenylindole, and images were collected using conventional and confocal microscopy. Both cranial and caudal CLs contained cells of heterogenous morphologies. Cells were arranged between collagen bundles and frequently had cytoplasmic processes. Some of these processes were long (type A cells), others were shorter, thicker and more branched (type B cells), and some had no processes (type C cells). Processes were frequently shown to contact other cells, extending longitudinally and transversely through the CLs. Cells with longer processes had fusiform nuclei, and those with no processes had rounded nuclei and were more frequent in the mid-substance of both CLs. Cells with long processes were more commonly noted in the CLs of the Greyhound. As contact between cells may facilitate direct communication, variances in cell morphology between breeds at a differing risk of CCL rupture may reflect differences in CL physiology. Copyright © 2012 Elsevier Ltd. All rights reserved.

7 CFR 51.586 - Serious damage.

Code of Federal Regulations, 2010 CFR

2010-01-01

... allowed for any one defect, shall be considered as serious damage: (a) Growth cracks when more than 4 branches are affected by growth cracks which are over one-half inch in length, or when more than 8 branches have growth cracks; (b) Horizontal cracks when more than 5 branches have horizontal cracks which are...

7 CFR 51.586 - Serious damage.

Code of Federal Regulations, 2011 CFR

2011-01-01

... allowed for any one defect, shall be considered as serious damage: (a) Growth cracks when more than 4 branches are affected by growth cracks which are over one-half inch in length, or when more than 8 branches have growth cracks; (b) Horizontal cracks when more than 5 branches have horizontal cracks which are...

7 CFR 51.586 - Serious damage.

Code of Federal Regulations, 2012 CFR

2012-01-01

... allowed for any one defect, shall be considered as serious damage: (a) Growth cracks when more than 4 branches are affected by growth cracks which are over one-half inch in length, or when more than 8 branches have growth cracks; (b) Horizontal cracks when more than 5 branches have horizontal cracks which are...

Bird exclosures for branches and whole trees.

Treesearch

Robert W. Campbell; Torolf R. Torgersen; Steven C. Forrest; Lorna C. Youngs

1981-01-01

Two types of lightweight, portable bird exclosures are described. One is for individual branches or branch tips; the other is for whole trees up to 9 m tall. Several alternative configurations and uses of these exclosures are discussed.

Technical activities of the configuration aeroelasticity branch

NASA Technical Reports Server (NTRS)

Cole, Stanley R. (Editor)

1991-01-01

A number of recent technical activities of the Configuration Aeroelasticity Branch of the NASA Langley Research Center are discussed in detail. The information on the research branch is compiled in twelve separate papers. The first of these topics is a summary of the purpose of the branch, including a full description of the branch and its associated projects and program efforts. The next ten papers cover specific projects and are as follows: Experimental transonic flutter characteristics of supersonic cruise configurations; Aeroelastic effects of spoiler surfaces mounted on a low aspect ratio rectangular wing; Planform curvature effects on flutter of 56 degree swept wing determined in Transonic Dynamics Tunnel (TDT); An introduction to rotorcraft testing in TDT; Rotorcraft vibration reduction research at the TDT; A preliminary study to determine the effects of tip geometry on the flutter of aft swept wings; Aeroelastic models program; NACA 0012 pressure model and test plan; Investigation of the use of extension twist coupling in composite rotor blades; and Improved finite element methods for rotorcraft structures. The final paper describes the primary facility operation by the branch, the Langley TDT.

Horizontal Gene Transfer and the History of Life

PubMed Central

Daubin, Vincent; Szöllősi, Gergely J.

2016-01-01

Microbes acquire DNA from a variety of sources. The last decades, which have seen the development of genome sequencing, have revealed that horizontal gene transfer has been a major evolutionary force that has constantly reshaped genomes throughout evolution. However, because the history of life must ultimately be deduced from gene phylogenies, the lack of methods to account for horizontal gene transfer has thrown into confusion the very concept of the tree of life. As a result, many questions remain open, but emerging methodological developments promise to use information conveyed by horizontal gene transfer that remains unexploited today. PMID:26801681

Morphology of arolia in Auchenorrhyncha (Insecta, Hemiptera).

PubMed

Friedemann, Katrin; Beutel, Rolf G

2014-11-01

The pretarsal arolium serves as an attachment device in many groups of insects, enabling them to walk efficiently on smooth surfaces, where claws alone do not provide sufficient foothold. The arolia of representatives of all major lineages of Auchenorrhyncha are described and illustrated, mainly using scanning electron microscopy and histology. Glands inside the lumen of the arolia are described for the first time in this group. It is shown that the morphology of arolia within Auchenorrhyncha differs considerably. Some of them are even distinctly bilobed. The cuticle of the contact zone is thickened and formed of branching chitinous rods. In some cases, two layers of rods oriented in different directions were found. An extended definition of "arolium" is proposed. © 2014 Wiley Periodicals, Inc.

Reframing and addressing horizontal violence as a workplace quality improvement concern.

PubMed

Taylor, Rosemary A; Taylor, Steven S

2018-06-27

To reframe horizontal violence as a quality improvement concern. Although the number of studies exploring horizontal violence has increased, evidence supporting the effectiveness of current interventions is weak and the problem persists. Often framed as an individual or interpersonal issue, horizontal violence has been recognized as a complex phenomenon that can only be understood through an examination of social, individual and organizational factors. As such, interventions to address horizontal violence must be applied systemically and address contributions from all sources. This is a discussion paper. This discussion is based on results of a study of nurses' perceptions of horizontal violence and review of the literature. Context is recognized as a contributing factor in human behavior, yet often overlooked in interventions to address horizontal violence. Moving the focus away from the individual and investigating systems contributions to horizontal violence using existing quality improvement frameworks is suggested. To date, efforts to address horizontal violence have not been proven effective. There is a call for a wider application and investigation of interventions. This reframing provides the system level application suggested and would address a broader range of factors contributing to the perpetuation of the phenomenon. © 2018 Wiley Periodicals, Inc.

Synthesis of branched metal nanostructures with controlled architecture and composition

NASA Astrophysics Data System (ADS)

Ortiz, Nancy

On account of their small size, metal nanoparticles are proven to be outstanding catalysts for numerous chemical transformations and represent promising platforms for applications in the fields of electronics, chemical sensing, medicine, and beyond. Many properties of metal nanoparticles are size-dependent and can be further manipulated through their shape and architecture (e.g., spherical vs. branched). Achieving morphology control of nanoparticles through solution-based techniques has proven challenging due to limited knowledge of morphology development in nanosyntheses. To overcome these complications, a systematic examination of the local ligand environment of metal precursors on nanostructure formation was undertaken to evaluate its contribution to nanoparticle nucleation rate and subsequent growth processes. Specifically, this thesis will provide evidence from ex situ studies---Transmission Electron Microscopy (TEM) and UV-visible spectroscopy (UV-Vis)---that support the hypothesis that strongly coordinated ligands delay burst-like nucleation to generate spherical metal nanoparticles and ligands with intermediate binding affinity regulate the gradual reduction of metal precursors to promote aggregated assembly of nanodendrites. These ex situ studies were coupled with a new in situ perspective, providing detailed understanding of metal precursor transformation, its direct relation to nanoparticle morphology development, and the ligand influence towards the formation of structurally complex metal nanostructures, using in situ synchrotron X-ray Diffraction (XRD) and Ultra Small-Angle X-ray Scattering (USAXS). The principles extracted from the study of monometallic nanostructure formation were also found to be generally applicable to the synthesis of bimetallic nanostructures, e.g., Pd-Pt architectures, with either core-shell or alloyed structures that were readily achieved by ligand selection. These outcomes provide a direct connection between fundamental

Computational models of airway branching morphogenesis.

PubMed

Varner, Victor D; Nelson, Celeste M

2017-07-01

The bronchial network of the mammalian lung consists of millions of dichotomous branches arranged in a highly complex, space-filling tree. Recent computational models of branching morphogenesis in the lung have helped uncover the biological mechanisms that construct this ramified architecture. In this review, we focus on three different theoretical approaches - geometric modeling, reaction-diffusion modeling, and continuum mechanical modeling - and discuss how, taken together, these models have identified the geometric principles necessary to build an efficient bronchial network, as well as the patterning mechanisms that specify airway geometry in the developing embryo. We emphasize models that are integrated with biological experiments and suggest how recent progress in computational modeling has advanced our understanding of airway branching morphogenesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

TCP transcription factor, BRANCH ANGLE DEFECTIVE 1 (BAD1), is required for normal tassel branch angle formation in maize.

PubMed

Bai, Fang; Reinheimer, Renata; Durantini, Diego; Kellogg, Elizabeth A; Schmidt, Robert J

2012-07-24

In grass inflorescences, a structure called the "pulvinus" is found between the inflorescence main stem and lateral branches. The size of the pulvinus affects the angle of the lateral branches that emerge from the main axis and therefore has a large impact on inflorescence architecture. Through EMS mutagenesis we have identified three complementation groups of recessive mutants in maize having defects in pulvinus formation. All mutants showed extremely acute tassel branch angles accompanied by a significant reduction in the size of the pulvinus compared with normal plants. Two of the complementation groups correspond to mutations in the previously identified genes, RAMOSA2 (RA2) and LIGULELESS1 (LG1). Mutants corresponding to a third group were cloned using mapped-based approaches and found to encode a new member of the plant-specific TCP (TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL NUCLEAR ANTIGEN FACTOR) family of DNA-binding proteins, BRANCH ANGLE DEFECTIVE 1 (BAD1). BAD1 is expressed in the developing pulvinus as well as in other developing tissues, including the tassels and juvenile leaves. Both molecular and genetics studies show that RA2 is upstream of BAD1, whereas LG1 may function in a separate pathway. Our findings demonstrate that BAD1 is a TCP class II gene that functions to promote cell proliferation in a lateral organ, the pulvinus, and influences inflorescence architecture by impacting the angle of lateral branch emergence.

Sidewall containment of liquid metal with horizontal alternating magnetic fields

DOEpatents

Pareg, Walter F.

1990-01-01

An apparatus for confining molten metal with a horizontal alternating magnetic field. In particular, this invention employs a magnet that can produce a horizontal alternating magnetic field to confine a molten metal at the edges of parallel horizontal rollers as a solid metal sheet is cast by counter-rotation of the rollers.

Sidewall containment of liquid metal with horizontal alternating magnetic fields

DOEpatents

Praeg, Walter F.

1995-01-01

An apparatus for confining molten metal with a horizontal alternating magnetic field. In particular, this invention employs a magnet that can produce a horizontal alternating magnetic field to confine a molten metal at the edges of parallel horizontal rollers as a solid metal sheet is cast by counter-rotation of the rollers.

Enzymes involved in branched-chain amino acid metabolism in humans.

PubMed

Adeva-Andany, María M; López-Maside, Laura; Donapetry-García, Cristóbal; Fernández-Fernández, Carlos; Sixto-Leal, Cristina

2017-06-01

Branched-chain amino acids (leucine, isoleucine and valine) are structurally related to branched-chain fatty acids. Leucine is 2-amino-4-methyl-pentanoic acid, isoleucine is 2-amino-3-methyl-pentanoic acid, and valine is 2-amino-3-methyl-butanoic acid. Similar to fatty acid oxidation, leucine and isoleucine produce acetyl-coA. Additionally, leucine generates acetoacetate and isoleucine yields propionyl-coA. Valine oxidation produces propionyl-coA, which is converted into methylmalonyl-coA and succinyl-coA. Branched-chain aminotransferase catalyzes the first reaction in the catabolic pathway of branched-chain amino acids, a reversible transamination that converts branched-chain amino acids into branched-chain ketoacids. Simultaneously, glutamate is converted in 2-ketoglutarate. The branched-chain ketoacid dehydrogenase complex catalyzes the irreversible oxidative decarboxylation of branched-chain ketoacids to produce branched-chain acyl-coA intermediates, which then follow separate catabolic pathways. Human tissue distribution and function of most of the enzymes involved in branched-chain amino acid catabolism is unknown. Congenital deficiencies of the enzymes involved in branched-chain amino acid metabolism are generally rare disorders. Some of them are associated with reduced pyruvate dehydrogenase complex activity and respiratory chain dysfunction that may contribute to their clinical phenotype. The biochemical phenotype is characterized by accumulation of the substrate to the deficient enzyme and its carnitine and/or glycine derivatives. It was established at the beginning of the twentieth century that the plasma level of the branched-chain amino acids is increased in conditions associated with insulin resistance such as obesity and diabetes mellitus. However, the potential clinical relevance of this elevation is uncertain.

Three ancient hormonal cues co-ordinate shoot branching in a moss.

PubMed

Coudert, Yoan; Palubicki, Wojtek; Ljung, Karin; Novak, Ondrej; Leyser, Ottoline; Harrison, C Jill

2015-03-25

Shoot branching is a primary contributor to plant architecture, evolving independently in flowering plant sporophytes and moss gametophytes. Mechanistic understanding of branching is largely limited to flowering plants such as Arabidopsis, which have a recent evolutionary origin. We show that in gametophytic shoots of Physcomitrella, lateral branches arise by re-specification of epidermal cells into branch initials. A simple model co-ordinating the activity of leafy shoot tips can account for branching patterns, and three known and ancient hormonal regulators of sporophytic branching interact to generate the branching pattern- auxin, cytokinin and strigolactone. The mode of auxin transport required in branch patterning is a key divergence point from known sporophytic pathways. Although PIN-mediated basipetal auxin transport regulates branching patterns in flowering plants, this is not so in Physcomitrella, where bi-directional transport is required to generate realistic branching patterns. Experiments with callose synthesis inhibitors suggest plasmodesmal connectivity as a potential mechanism for transport.

Three ancient hormonal cues co-ordinate shoot branching in a moss

PubMed Central

Coudert, Yoan; Palubicki, Wojtek; Ljung, Karin; Novak, Ondrej; Leyser, Ottoline; Harrison, C Jill

2015-01-01

Shoot branching is a primary contributor to plant architecture, evolving independently in flowering plant sporophytes and moss gametophytes. Mechanistic understanding of branching is largely limited to flowering plants such as Arabidopsis, which have a recent evolutionary origin. We show that in gametophytic shoots of Physcomitrella, lateral branches arise by re-specification of epidermal cells into branch initials. A simple model co-ordinating the activity of leafy shoot tips can account for branching patterns, and three known and ancient hormonal regulators of sporophytic branching interact to generate the branching pattern- auxin, cytokinin and strigolactone. The mode of auxin transport required in branch patterning is a key divergence point from known sporophytic pathways. Although PIN-mediated basipetal auxin transport regulates branching patterns in flowering plants, this is not so in Physcomitrella, where bi-directional transport is required to generate realistic branching patterns. Experiments with callose synthesis inhibitors suggest plasmodesmal connectivity as a potential mechanism for transport. DOI: http://dx.doi.org/10.7554/eLife.06808.001 PMID:25806686

Taxonomic revision of Gelidium tsengii and Gelidium honghaiwanense sp. nov. (Gelidiales, Rhodophyta) from China based upon molecular and morphological data analyses

NASA Astrophysics Data System (ADS)

Wang, Xulei; Xia, Bangmei; Bottalico, Antonella; Wang, Guangce

2017-11-01

The taxonomic relationship of Chinese Gelidium tsengii and Gelidium johnstonii was ambiguous. For almost 20 years they have been regarded as distinct taxa and until 2002 G. johnstonii was considered as a misapplied name of G. tsengii. In this study, herbarium specimens that initially attributed to G. tsengii and fresh G. tsengii specimens were used to address the taxonomic issues. In phylogenetic studies, G. tsengii from Dayawan, China, near the type locality of G. tsengii and G. johnstonii from Sonora, Mexico, the type locality of G. johnstonii, formed a monophyletic group with maximum support in rbcL and COI genes analyses, indicating that they were genetically identical. In morphological studies, G. tsengii was similar to G. johnstonii in branching pattern, inner structures and fructiferous organs. Consequently, we considered that semi-circular outline of G. tsengii could no longer be treated as a discrimating feature. G. johnstonii had priority of publication and according to the International Code of Botanical Nomenclature, G. tsengii was proposed as a synonym of G. johnstonii. Gelidium honghaiwanense sp. nov. was described from Guangdong, China on the basis of morphological and molecular data. For vegetative structures, it was characterized by flattened upright frond, regular two-three times branches pinnate or alternate and clavate ultimate branchlets. For reproductive structures, the tetrasporangial sori were in the apical part of branches and the tetrasporangial branchlets were distichously distributed along second order branches. The present study clarified the relationship between G. tsengii and G. johnstonii from Guangdong and added a new Gelidium species to the Chinese algal flora.

System Finds Horizontal Location of Center of Gravity

NASA Technical Reports Server (NTRS)

Johnston, Albert S.; Howard, Richard T.; Brewster, Linda L.

2006-01-01

An instrumentation system rapidly and repeatedly determines the horizontal location of the center of gravity of a laboratory vehicle that slides horizontally on three air bearings (see Figure 1). Typically, knowledge of the horizontal center-of-mass location of such a vehicle is needed in order to balance the vehicle properly for an experiment and/or to assess the dynamic behavior of the vehicle. The system includes a load cell above each air bearing, electronic circuits that generate digital readings of the weight on each load cell, and a computer equipped with software that processes the readings. The total weight and, hence, the mass of the vehicle are computed from the sum of the load-cell weight readings. Then the horizontal position of the center of gravity is calculated straightforwardly as the weighted sum of the known position vectors of the air bearings, the contribution of each bearing being proportional to the weight on that bearing. In the initial application for which this system was devised, the center- of-mass calculation is particularly simple because the air bearings are located at corners of an equilateral triangle. However, the system is not restricted to this simple geometry. The system acquires and processes weight readings at a rate of 800 Hz for each load cell. The total weight and the horizontal location of the center of gravity are updated at a rate of 800/3 approx. equals 267 Hz. In a typical application, a technician would use the center-of-mass output of this instrumentation system as a guide to the manual placement of small weights on the vehicle to shift the center of gravity to a desired horizontal position. Usually, the desired horizontal position is that of the geometric center. Alternatively, this instrumentation system could be used to provide position feedback for a control system that would cause weights to be shifted automatically (see Figure 2) in an effort to keep the center of gravity at the geometric center.

Morphological Evolution of Nanocluster Aggregates and Single Crystals in Alkaline Zinc Electrodeposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Desai, D; Turney, DE; Anantharaman, B

2014-04-24

The morphology of Zn electrodeposits is studied on carbon-coated transmission electron microscopy grids. At low over-potentials (eta = -50 mV), the morphology develops by aggregation at two distinct length scales: similar to 5 nm diameter monocrystalline nanoclusters form similar to 50 nm diameter polycrystalline aggregates, and the aggregates form a branched network. Epitaxial (00 (0) over bar2) growth above an overpotential of vertical bar eta(c)vertical bar > 125 mV leads to the formation of hexagonal single crystals up to 2 mu m in diameter. Potentiostatic current transients were used to calculate the nucleation rate from Scharifker et al.'s model. Themore » exp(eta) dependence of the nucleation rates indicates that atomistic nucleation theory explains the nucleation process better than Volmer-Weber theory. A kinetic model is provided using the rate equations of vapor solidification to simulate the evolution of the different morphologies. On solving these equations, we show that aggregation is attributed to cluster impingement and cluster diffusion while single-crystal formation is attributed to direct attachment.« less

Automated branching pattern report generation for laparoscopic surgery assistance

NASA Astrophysics Data System (ADS)

Oda, Masahiro; Matsuzaki, Tetsuro; Hayashi, Yuichiro; Kitasaka, Takayuki; Misawa, Kazunari; Mori, Kensaku

2015-05-01

This paper presents a method for generating branching pattern reports of abdominal blood vessels for laparoscopic gastrectomy. In gastrectomy, it is very important to understand branching structure of abdominal arteries and veins, which feed and drain specific abdominal organs including the stomach, the liver and the pancreas. In the real clinical stage, a surgeon creates a diagnostic report of the patient anatomy. This report summarizes the branching patterns of the blood vessels related to the stomach. The surgeon decides actual operative procedure. This paper shows an automated method to generate a branching pattern report for abdominal blood vessels based on automated anatomical labeling. The report contains 3D rendering showing important blood vessels and descriptions of branching patterns of each vessel. We have applied this method for fifty cases of 3D abdominal CT scans and confirmed the proposed method can automatically generate branching pattern reports of abdominal arteries.

[Analysis of horizontal transfer gene of Bombyx mori NPV].

PubMed

Duan, Hai-Rong; Qiu, De-Bin; Gong, Cheng-Liang; Huang, Mo-Li

2011-06-01

For research on genetic characters and evolutionary origin of the genome of baculoviruses, a comprehensive homology search and phylogenetic analysis of the complete genomes of Bombyx mori NPV and Bombyx mori were used. Three horizontally transferred genes (inhibitor of apoptosis, chitinase, and UDP-glucosyltransferase) were identified, and there was evidence that all of these genes were derived from the insect host. The results of analysis showed lots of differences between the features of horizontal transferred genes and the ones of whole genomic genes, such as nucleotide composition, codon usagebias and selection pressure. These results reconfirmed that the horizontally transferred genes are exogenous. The analysis of gene function suggested that horizontally transferred genes acquired from an ancestral host insect can increase the efficiency of baculoviruses transmission.

Spectrum syntheses of high-resolution integrated light spectra of Galactic globular clusters

NASA Astrophysics Data System (ADS)

Sakari, Charli M.; Shetrone, Matthew; Venn, Kim; McWilliam, Andrew; Dotter, Aaron

2013-09-01

Spectrum syntheses for three elements (Mg, Na and Eu) in high-resolution integrated light spectra of the Galactic globular clusters 47 Tuc, M3, M13, NGC 7006 and M15 are presented, along with calibration syntheses of the solar and Arcturus spectra. Iron abundances in the target clusters are also derived from integrated light equivalent width analyses. Line profiles in the spectra of these five globular clusters are well fitted after careful consideration of the atomic and molecular spectral features, providing levels of precision that are better than equivalent width analyses of the same integrated light spectra, and that are comparable to the precision in individual stellar analyses. The integrated light abundances from the 5528 and 5711 Å Mg I lines, the 6154 and 6160 Å Na I lines, and the 6645 Å Eu II line fall within the observed ranges from individual stars; however, these integrated light abundances do not always agree with the average literature abundances. Tests with the second parameter clusters M3, M13 and NGC 7006 show that assuming an incorrect horizontal branch morphology is likely to have only a small ( ≲ 0.06 dex) effect on these Mg, Na and Eu abundances. These tests therefore show that integrated light spectrum syntheses can be applied to unresolved globular clusters over a wide range of metallicities and horizontal branch morphologies. Such high precision in integrated light spectrum syntheses is valuable for interpreting the chemical abundances of globular cluster systems around other galaxies.

Molecular basis of branched peptides resistance to enzyme proteolysis.

PubMed

Falciani, Chiara; Lozzi, Luisa; Pini, Alessandro; Corti, Federico; Fabbrini, Monica; Bernini, Andrea; Lelli, Barbara; Niccolai, Neri; Bracci, Luisa

2007-03-01

We found that synthetic peptides in the form of dendrimers become resistant to proteolysis. To determine the molecular basis of this resistance, different bioactive peptides were synthesized in monomeric, two-branched and tetra-branched form and incubated with human plasma and serum. Proteolytic resistance of branched multimeric sequences was compared to that of the same peptides synthesized as multimeric linear molecules. Unmodified peptides and cleaved sequences were detected by high pressure liquid chromatography and mass spectrometry. An increase in peptide copies did not increase peptide resistance in linear multimeric sequences, whereas multimericity progressively enhanced proteolytic stability of branched multimeric peptides. A structure-based hypothesis of branched peptide resistance to proteolysis by metallopeptidases is presented.

Martian impact crater ejecta morphologies and their potential as indicators of subsurface volatile distribution

NASA Technical Reports Server (NTRS)

Barlow, Nadine G.

1991-01-01

Many martian impact craters ejecta morphologies suggestive of fluidization during ejecta emplacement. Impact into subsurface volatile reserviors (i.e., water, ice, CO2, etc.) is the mechanism favored by many scientists, although acceptance of this mechanism is not unanimous. In recent years, a number of studies were undertaken to better understand possible relationships between ejecta morphology and latitude, longitude, crater diameter, and terrain. These results suggest that subsurface volatiles do influence the formation of specific ejecta morphologies and may provide clues to the vertical and horizontal distribution of volatiles in more localized regions of Mars. The location of these volatile reservoirs will be important to humans exploring and settling Mars in the future. Qualitative descriptions of ejecta morphology and quantitative analyses of ejecta sinuosity and ejecta lobe areal extent from the basis of the studies. Ejecta morphology studies indicate that morphology is correlated with crater diameter and latitude, and, using depth-diameter relationships, these correlations strongly suggest that changes in morphology are related to transition among subsurface layers with varying amounts of volatiles. Ejecta sinuosity studies reveal correlations between degree of sinuosity (lobateness) and crater morphology, diameter, latitude, and terrain. Lobateness, together with variations in areal extent of the lobate ejecta blanket with morphology and latitude, probably depends most directly on the ejecta emplacement process. The physical parameters measured here can be compared with those predicted by existing ejecta emplacement models. Some of these parameters are best reproduced by models requiring incorporation of volatiles within the ejecta. However, inconsistencies between other parameters and the models indicate that more detailed modeling is necessary before the location of volatile reservoirs can be confidently predicted based on ejecta morphology studies

47 CFR 32.6341 - Large private branch exchange expense.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Large private branch exchange expense. 32.6341... Large private branch exchange expense. This account shall include expenses associated with large private branch exchanges. Expenses associated with company internal use communication equipment shall be recorded...

Stasis and convergence characterize morphological evolution in eupolypod II ferns.

PubMed

Sundue, Michael A; Rothfels, Carl J

2014-01-01

Patterns of morphological evolution at levels above family rank remain underexplored in the ferns. The present study seeks to address this gap through analysis of 79 morphological characters for 81 taxa, including representatives of all ten families of eupolypod II ferns. Recent molecular phylogenetic studies demonstrate that the evolution of the large eupolypod II clade (which includes nearly one-third of extant fern species) features unexpected patterns. The traditional 'athyrioid' ferns are scattered across the phylogeny despite their apparent morphological cohesiveness, and mixed among these seemingly conservative taxa are morphologically dissimilar groups that lack any obvious features uniting them with their relatives. Maximum-likelihood and maximum-parsimony character optimizations are used to determine characters that unite the seemingly disparate groups, and to test whether the polyphyly of the traditional athyrioid ferns is due to evolutionary stasis (symplesiomorphy) or convergent evolution. The major events in eupolypod II character evolution are reviewed, and character and character state concepts are reappraised, as a basis for further inquiries into fern morphology. Characters were scored from the literature, live plants and herbarium specimens, and optimized using maximum-parsimony and maximum-likelihood, onto a highly supported topology derived from maximum-likelihood and Bayesian analysis of molecular data. Phylogenetic signal of characters were tested for using randomization methods and fitdiscrete. The majority of character state changes within the eupolypod II phylogeny occur at the family level or above. Relative branch lengths for the morphological data resemble those from molecular data and fit an ancient rapid radiation model (long branches subtended by very short backbone internodes), with few characters uniting the morphologically disparate clades. The traditional athyrioid ferns were circumscribed based upon a combination of

Stasis and convergence characterize morphological evolution in eupolypod II ferns

PubMed Central

Sundue, Michael A.; Rothfels, Carl J.

2014-01-01

Background and Aims Patterns of morphological evolution at levels above family rank remain underexplored in the ferns. The present study seeks to address this gap through analysis of 79 morphological characters for 81 taxa, including representatives of all ten families of eupolypod II ferns. Recent molecular phylogenetic studies demonstrate that the evolution of the large eupolypod II clade (which includes nearly one-third of extant fern species) features unexpected patterns. The traditional ‘athyrioid’ ferns are scattered across the phylogeny despite their apparent morphological cohesiveness, and mixed among these seemingly conservative taxa are morphologically dissimilar groups that lack any obvious features uniting them with their relatives. Maximum-likelihood and maximum-parsimony character optimizations are used to determine characters that unite the seemingly disparate groups, and to test whether the polyphyly of the traditional athyrioid ferns is due to evolutionary stasis (symplesiomorphy) or convergent evolution. The major events in eupolypod II character evolution are reviewed, and character and character state concepts are reappraised, as a basis for further inquiries into fern morphology. Methods Characters were scored from the literature, live plants and herbarium specimens, and optimized using maximum-parsimony and maximum-likelihood, onto a highly supported topology derived from maximum-likelihood and Bayesian analysis of molecular data. Phylogenetic signal of characters were tested for using randomization methods and fitdiscrete. Key Results The majority of character state changes within the eupolypod II phylogeny occur at the family level or above. Relative branch lengths for the morphological data resemble those from molecular data and fit an ancient rapid radiation model (long branches subtended by very short backbone internodes), with few characters uniting the morphologically disparate clades. The traditional athyrioid ferns were

Sidewall containment of liquid metal with horizontal alternating magnetic fields

DOEpatents

Praeg, W.F.

1995-01-31

An apparatus is disclosed for confining molten metal with a horizontal alternating magnetic field. In particular, this invention employs a magnet that can produce a horizontal alternating magnetic field to confine a molten metal at the edges of parallel horizontal rollers as a solid metal sheet is cast by counter-rotation of the rollers. 19 figs.

Improving proton conduction pathways in di- and triblock copolymer membranes: Branched versus linear side chains

NASA Astrophysics Data System (ADS)

Dorenbos, G.

2017-06-01

Phase separation within a series of polymer membranes in the presence of water is studied by dissipative particle dynamics. Each polymer contains hydrophobic A beads and hydrophilic C beads. Three parent architectures are constructed from a backbone composed of connected hydrophobic A beads to which short ([C]), long ([A3C]), or symmetrically branched A5[AC][AC] side chains spring off. Three di-block copolymer derivatives are constructed by covalently bonding an A30 block to each parent architecture. Also three tri-blocks with A15 blocks attached to both ends of each parent architecture are modeled. Monte Carlo tracer diffusion calculations through the water containing pores for 1226 morphologies reveal that water diffusion for parent architectures is slowest and diffusion through the di-blocks is fastest. Furthermore, diffusion increases with side chain length and is highest for branched side chains. This is explained by the increase of water pore size with , which is the average number of bonds that A beads are separated from a nearest C bead. Optimization of within the amphiphilic parent architecture is expected to be essential in improving proton conduction in polymer electrolyte membranes.

Structural Dynamics Branch research and accomplishments for FY 1990

NASA Technical Reports Server (NTRS)

1991-01-01

Presented here is a collection of FY 1990 research highlights from the Structural Dynamics Branch at the NASA Lewis Research Center. Highlights are from the branch's major work areas: aeroelasticity, vibration control, dynamic systems, and computational structural methods. A listing is given of FY 1990 branch publications.

Comparative transcriptome analysis reveals conserved branching morphogenesis related genes involved in chamber formation of catfish swimbladder.

PubMed

Yang, Yujia; Fu, Qiang; Liu, Yang; Wang, Xiaozhu; Dunham, Rex; Liu, Shikai; Bao, Lisui; Zeng, Qifan; Zhou, Tao; Li, Ning; Qin, Zhenkui; Jiang, Chen; Gao, Dongya; Liu, Zhanjiang

2018-01-01

The swimbladder is an internal gas-filled organ in teleosts. Its major function is to regulate buoyancy. The swimbladder exhibits great variation in size, shape, and number of compartments or chambers among teleosts. However, genomic control of swimbladder variation is unknown. Channel catfish ( Ictalurus punctatus), blue catfish ( Ictalurus furcatus), and their F1 hybrids of female channel catfish × male blue catfish (C × B hybrid catfish) provide a good model in which to investigate the swimbladder morphology, because channel catfish possess a single-chambered swimbladder, whereas blue catfish possess a bichambered swimbladder; C × B hybrid catfish possess a bichambered swimbladder but with a significantly reduced posterior chamber. Here we determined the transcriptional profiles of swimbladder from channel catfish, blue catfish, and C × B hybrid catfish. We examined their transcriptomes at both the fingerling and adult stages. Through comparative transcriptome analysis, ~4,000 differentially expressed genes (DEGs) were identified. Among these DEGs, members of the Wnt signaling pathway ( wnt1, wnt2, nfatc1, rac2), Hedgehog signaling pathway ( shh), and growth factors ( fgf10, igf-1) were identified. As these genes were known to be important for branching morphogenesis of mammalian lung and of mammary glands, their association with budding of the posterior chamber primordium and progressive development of bichambered swimbladder in fish suggest that these branching morphogenesis-related genes and their functions in branching are evolutionarily conserved across a broad spectrum of species.

Electroluminescence from completely horizontally oriented dye molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Komino, Takeshi; Center for Organic Photonics and Electronics Research, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395; Japan Science and Technology Agency, ERATO, Adachi Molecular Exciton Engineering Project, 744 Motooka, Nishi, Fukuoka 819-0395

2016-06-13

A complete horizontal molecular orientation of a linear-shaped thermally activated delayed fluorescent guest emitter 2,6-bis(4-(10Hphenoxazin-10-yl)phenyl)benzo[1,2-d:5,4-d′] bis(oxazole) (cis-BOX2) was obtained in a glassy host matrix by vapor deposition. The orientational order of cis-BOX2 depended on the combination of deposition temperature and the type of host matrix. Complete horizontal orientation was obtained when a thin film with cis-BOX2 doped in a 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) host matrix was fabricated at 200 K. The ultimate orientation of guest molecules originates from not only the kinetic relaxation but also the kinetic stability of the deposited guest molecules on the film surface during film growth. Utilizing the ultimatemore » orientation, a highly efficient organic light-emitting diode with the external quantum efficiency of 33.4 ± 2.0% was realized. The thermal stability of the horizontal orientation of cis-BOX2 was governed by the glass transition temperature (T{sub g}) of the CBP host matrix; the horizontal orientation was stable unless the film was annealed above T{sub g}.« less

Plantmediated horizontal transmission of Wolbachia between whiteflies

PubMed Central

Li, Shao-Jian; Ahmed, Muhammad Z; Lv, Ning; Shi, Pei-Qiong; Wang, Xing-Min; Huang, Ji-Lei; Qiu, Bao-Li

2017-01-01

Maternal transmission is the main transmission pathway of facultative bacterial endosymbionts, but phylogenetically distant insect hosts harbor closely related endosymbionts, suggesting that horizontal transmission occurs in nature. Here we report the first case of plant-mediated horizontal transmission of Wolbachia between infected and uninfected Bemisia tabaci AsiaII7 whiteflies. After infected whiteflies fed on cotton leaves, Wolbachia was visualized, both in the phloem vessels and in some novel ‘reservoir' spherules along the phloem by fluorescence in situ hybridization using Wolbachia-specific 16S rRNA probes and transmission electron microscopy. Wolbachia persisted in the plant leaves for at least 50 days. When the Wolbachia-free whiteflies fed on the infected plant leaves, the majority of them became infected with the symbiont and vertically transmitted it to their progeny. Multilocus sequence typing and sequencing of the wsp (Wolbachia surface protein) gene confirmed that the sequence type of Wolbachia in the donor whiteflies, cotton phloem and the recipient whiteflies are all identical (sequence type 388). These results were replicated using cowpea and cucumber plants, suggesting that horizontal transmission is also possible through other plant species. Our findings may help explain why Wolbachia bacteria are so abundant in arthropods, and suggest that in some species, Wolbachia may be maintained in populations by horizontal transmission. PMID:27935594

Influence of pavement condition on horizontal curve safety.

PubMed

Buddhavarapu, Prasad; Banerjee, Ambarish; Prozzi, Jorge A

2013-03-01

Crash statistics suggest that horizontal curves are the most vulnerable sites for crash occurrence. These crashes are often severe and many involve at least some level of injury due to the nature of the collisions. Ensuring the desired pavement surface condition is one potentially effective strategy to reduce the occurrence of severe accidents on horizontal curves. This study sought to develop crash injury severity models by integrating crash and pavement surface condition databases. It focuses on developing a causal relationship between pavement condition indices and severity level of crashes occurring on two-lane horizontal curves in Texas. In addition, it examines the suitability of the existing Skid Index for safety maintenance of two-lane curves. Significant correlation is evident between pavement condition and crash injury severity on two-lane undivided horizontal curves in Texas. Probability of a crash becoming fatal is appreciably sensitive to certain pavement indices. Data suggested that road facilities providing a smoother and more comfortable ride are vulnerable to severe crashes on horizontal curves. In addition, the study found that longitudinal skid measurement barely correlates with injury severity of crashes occurring on curved portions. The study recommends exploring the option of incorporating lateral friction measurement into Pavement Management System (PMS) databases specifically at curved road segments. Copyright © 2012 Elsevier Ltd. All rights reserved.

Spatial mapping and quantification of developmental branching morphogenesis.

PubMed

Short, Kieran; Hodson, Mark; Smyth, Ian

2013-01-15

Branching morphogenesis is a fundamental developmental mechanism that shapes the formation of many organs. The complex three-dimensional shapes derived by this process reflect equally complex genetic interactions between branching epithelia and their surrounding mesenchyme. Despite the importance of this process to normal adult organ function, analysis of branching has been stymied by the absence of a bespoke method to quantify accurately the complex spatial datasets that describe it. As a consequence, although many developmentally important genes are proposed to influence branching morphogenesis, we have no way of objectively assessing their individual contributions to this process. We report the development of a method for accurately quantifying many aspects of branching morphogenesis and we demonstrate its application to the study of organ development. As proof of principle we have employed this approach to analyse the developing mouse lung and kidney, describing the spatial characteristics of the branching ureteric bud and pulmonary epithelia. To demonstrate further its capacity to profile unrecognised genetic contributions to organ development, we examine Tgfb2 mutant kidneys, identifying elements of both developmental delay and specific spatial dysmorphology caused by haplo-insufficiency for this gene. This technical advance provides a crucial resource that will enable rigorous characterisation of the genetic and environmental factors that regulate this essential and evolutionarily conserved developmental mechanism.

A case of modular phenotypic plasticity in the depth gradient for the gorgonian coral Antillogorgia bipinnata (Cnidaria: Octocorallia).

PubMed

Calixto-Botía, Iván; Sánchez, Juan A

2017-02-17

Phenotypic plasticity, as a phenotypic response induced by the environment, has been proposed as a key factor in the evolutionary history of corals. A significant number of octocoral species show high phenotypic variation, exhibiting a strong overlap in intra- and inter-specific morphologic variation. This is the case of the gorgonian octocoral Antillogorgia bipinnata (Verrill 1864), which shows three polyphyletic morphotypes along a bathymetric gradient. This research tested the phenotypic plasticity of modular traits in A. bipinnata with a reciprocal transplant experiment involving 256 explants from two morphotypes in two locations and at two depths. Vertical and horizontal length and number of new branches were compared 13 weeks following transplant. The data were analysed with a linear mixed-effects model and a graphic approach by reaction norms. At the end of the experiment, 91.8% of explants survived. Lower vertical and horizontal growth rates and lower branch promotion were found for deep environments compared to shallow environments. The overall variation behaved similarly to the performance of native transplants. In particular, promotion of new branches showed variance mainly due to a phenotypic plastic effect. Globally, environmental and genotypic effects explain the variation of the assessed traits. Survival rates besides plastic responses suggest an intermediate scenario between adaptive plasticity and local adaptation that may drive a potential process of adaptive divergence along depth cline in A. bipinnata.

Fluoropolymer Dynamics: Effects of Perfluoromethyl Branches

NASA Astrophysics Data System (ADS)

Eby, R. K.; Holt, D. B.; Farmer, B. L.; Adams, D. D.

1997-03-01

Previous simulations of polytetrafluoroethylene (PTFE) in the solid state showed that the interaction and movement of helix reversals plays an important role in the dynamic behavior of this important polymer. Copolymers of TFE and hexafluoropropylene (HFP), which can be viewed as PTFE with perfluoromethyl (PFM) group branch defects, is also widely used. Molecular mechanics and dynamics calculations have been performed with PTFE chain clusters containing PFM branches to investigate the effect of these defects on the local crystalline environment (and vice versa) and on the motions and interactions of helix reversals. Initial results indicate that helix reversals are attracted to sites of PFM branches in a chain. Such an interaction will impede the motions of helix reversals and have an impact on macroscopic mechanical properties such as resistance to plastic deformation under shear.

Reducing economic risk in areally anisotropic formations with multiple-lateral horizontal wells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, J.; Economides, M.J.; Frick, T.P.

1995-12-31

Well orientation is critical to horizontal well performance in areally anisotropic reservoirs. A horizontal well, drilled normal to the direction of maximum permeability, will have higher productivity than one drilled in any other arbitrary direction. Currently, horizontal permeability magnitudes and even indications of direction are rarely measured in the field. Based on well performance modeling and economic evaluation, this study attempts to determine the relative attractiveness of horizontal wells with multiple-laterals. The work exposes the economic risk in ignoring horizontal permeability magnitudes and directions and demonstrates the importance of adequate reservoir testing. A new rationalization for multiple-lateral horizontal wells ismore » the reduction of the economic risk associated with poor reservoir characterization in areally anisotropic formations while increasing the incremental net present value (NPV) over single-horizontal wells.« less

AmeriFlux US-WBW Walker Branch Watershed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyers, Tilden

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site US-WBW Walker Branch Watershed. Site Description - The stand is over 50 years old, having regenerated from agricultural land.This site is located near Oak Ridge, Tennessee near the Walker Branch Watershed.

Radioiodinated branched carbohydrates

DOEpatents

Goodman, Mark M.; Knapp, Jr., Furn F.

1989-01-01

A radioiodinated branched carbohydrate for tissue imaging. Iodine-123 is stabilized in the compound by attaching it to a vinyl functional group that is on the carbohydrate. The compound exhibits good uptake and retention and is promising in the development of radiopharmaceuticals for brain, heart and tumor imaging.

20 CFR 422.5 - District offices and branch offices.

Code of Federal Regulations, 2012 CFR

2012-04-01

... office is the manager. The principal officer in each branch office is the officer-in-charge. Each... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false District offices and branch offices. 422.5... and Functions of the Social Security Administration § 422.5 District offices and branch offices. There...

20 CFR 422.5 - District offices and branch offices.

Code of Federal Regulations, 2014 CFR

2014-04-01

... office is the manager. The principal officer in each branch office is the officer-in-charge. Each... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false District offices and branch offices. 422.5... and Functions of the Social Security Administration § 422.5 District offices and branch offices. There...

20 CFR 422.5 - District offices and branch offices.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false District offices and branch offices. 422.5... and Functions of the Social Security Administration § 422.5 District offices and branch offices. There are over 700 social security district offices and branch offices located in the principal cities and...

Structural dynamics branch research and accomplishments to FY 1992

NASA Technical Reports Server (NTRS)

Lawrence, Charles

1992-01-01

This publication contains a collection of fiscal year 1992 research highlights from the Structural Dynamics Branch at NASA LeRC. Highlights from the branch's major work areas--Aeroelasticity, Vibration Control, Dynamic Systems, and Computational Structural Methods are included in the report as well as a listing of the fiscal year 1992 branch publications.

Stochastic and deterministic causes of streamer branching in liquid dielectrics

NASA Astrophysics Data System (ADS)

Jadidian, Jouya; Zahn, Markus; Lavesson, Nils; Widlund, Ola; Borg, Karl

2013-08-01

Streamer branching in liquid dielectrics is driven by stochastic and deterministic factors. The presence of stochastic causes of streamer branching such as inhomogeneities inherited from noisy initial states, impurities, or charge carrier density fluctuations is inevitable in any dielectric. A fully three-dimensional streamer model presented in this paper indicates that deterministic origins of branching are intrinsic attributes of streamers, which in some cases make the branching inevitable depending on shape and velocity of the volume charge at the streamer frontier. Specifically, any given inhomogeneous perturbation can result in streamer branching if the volume charge layer at the original streamer head is relatively thin and slow enough. Furthermore, discrete nature of electrons at the leading edge of an ionization front always guarantees the existence of a non-zero inhomogeneous perturbation ahead of the streamer head propagating even in perfectly homogeneous dielectric. Based on the modeling results for streamers propagating in a liquid dielectric, a gauge on the streamer head geometry is introduced that determines whether the branching occurs under particular inhomogeneous circumstances. Estimated number, diameter, and velocity of the born branches agree qualitatively with experimental images of the streamer branching.

Should tsunami simulations include a nonzero initial horizontal velocity?

NASA Astrophysics Data System (ADS)

Lotto, Gabriel C.; Nava, Gabriel; Dunham, Eric M.

2017-08-01

Tsunami propagation in the open ocean is most commonly modeled by solving the shallow water wave equations. These equations require initial conditions on sea surface height and depth-averaged horizontal particle velocity or, equivalently, horizontal momentum. While most modelers assume that initial velocity is zero, Y.T. Song and collaborators have argued for nonzero initial velocity, claiming that horizontal displacement of a sloping seafloor imparts significant horizontal momentum to the ocean. They show examples in which this effect increases the resulting tsunami height by a factor of two or more relative to models in which initial velocity is zero. We test this claim with a "full-physics" integrated dynamic rupture and tsunami model that couples the elastic response of the Earth to the linearized acoustic-gravitational response of a compressible ocean with gravity; the model self-consistently accounts for seismic waves in the solid Earth, acoustic waves in the ocean, and tsunamis (with dispersion at short wavelengths). Full-physics simulations of subduction zone megathrust ruptures and tsunamis in geometries with a sloping seafloor confirm that substantial horizontal momentum is imparted to the ocean. However, almost all of that initial momentum is carried away by ocean acoustic waves, with negligible momentum imparted to the tsunami. We also compare tsunami propagation in each simulation to that predicted by an equivalent shallow water wave simulation with varying assumptions regarding initial velocity. We find that the initial horizontal velocity conditions proposed by Song and collaborators consistently overestimate the tsunami amplitude and predict an inconsistent wave profile. Finally, we determine tsunami initial conditions that are rigorously consistent with our full-physics simulations by isolating the tsunami waves from ocean acoustic and seismic waves at some final time, and backpropagating the tsunami waves to their initial state by solving the

Horizontal gene transfer in the acquisition of novel traits by metazoans

PubMed Central

Boto, Luis

2014-01-01

Horizontal gene transfer is accepted as an important evolutionary force modulating the evolution of prokaryote genomes. However, it is thought that horizontal gene transfer plays only a minor role in metazoan evolution. In this paper, I critically review the rising evidence on horizontally transferred genes and on the acquisition of novel traits in metazoans. In particular, I discuss suspected examples in sponges, cnidarians, rotifers, nematodes, molluscs and arthropods which suggest that horizontal gene transfer in metazoans is not simply a curiosity. In addition, I stress the scarcity of studies in vertebrates and other animal groups and the importance of forthcoming studies to understand the importance and extent of horizontal gene transfer in animals. PMID:24403327

Geological-morphological description of the Lakshmi planum (photomap of the Venusian surface sheet B-4)

NASA Technical Reports Server (NTRS)

Pronin, A. A.

1987-01-01

The Lakshmi Planum and its surrounding area (together comprising a single structure) are described in morphological terms on the basis of Venera 15 and 16 photomap data. Plume ascent from the planetary interior and subsequent horizontal spreading represent the underlying mechanisms behind structural formation: folding and/or imbricating accompany these processes. In effect, the Laksmi structure can be regarded as a local spreading center. Its structural dimensions attest to the role that asthenospheric currents played in its formation.

Environmental control of branching in petunia.

PubMed

Drummond, Revel S M; Janssen, Bart J; Luo, Zhiwei; Oplaat, Carla; Ledger, Susan E; Wohlers, Mark W; Snowden, Kimberley C

2015-06-01

Plants alter their development in response to changes in their environment. This responsiveness has proven to be a successful evolutionary trait. Here, we tested the hypothesis that two key environmental factors, light and nutrition, are integrated within the axillary bud to promote or suppress the growth of the bud into a branch. Using petunia (Petunia hybrida) as a model for vegetative branching, we manipulated both light quality (as crowding and the red-to-far-red light ratio) and phosphate availability, such that the axillary bud at node 7 varied from deeply dormant to rapidly growing. In conjunction with the phenotypic characterization, we also monitored the state of the strigolactone (SL) pathway by quantifying SL-related gene transcripts. Mutants in the SL pathway inhibit but do not abolish the branching response to these environmental signals, and neither signal is dominant over the other, suggesting that the regulation of branching in response to the environment is complex. We have isolated three new putatively SL-related TCP (for Teosinte branched1, Cycloidia, and Proliferating cell factor) genes from petunia, and have identified that these TCP-type transcription factors may have roles in the SL signaling pathway both before and after the reception of the SL signal at the bud. We show that the abundance of the receptor transcript is regulated by light quality, such that axillary buds growing in added far-red light have greatly increased receptor transcript abundance. This suggests a mechanism whereby the impact of any SL signal reaching an axillary bud is modulated by the responsiveness of these cells to the signal. © 2015 American Society of Plant Biologists. All Rights Reserved.

Crack stability and branching at interfaces

NASA Astrophysics Data System (ADS)

Thomson, Robb

1995-11-01

The various events that occur at a crack on an interface are explored, and described in terms of a simple graphical construction called the crack stability diagram. For simple Griffith cleavage in a homogeneous material, the stability diagram is a sector of a circle in the space of stress intensity factors, KI/KII. The Griffith circle is limited in both positive and negative KII directions by nonblunting dislocation emission on the cleavage plane. For a branching plane inclined at an angle to the original cleavage plane, both cleavage and emission (which blunts the crack) can be described as a balance between an elastic driving force and a lattice resistance for the event. We use an analytic expression obtained by Cotterell and Rice for cleavage, and show that it is an excellent approximation, but show that the lattice resistance includes a cornering resistance, in addition to the standard surface energy in the final cleavage criterion. Our discussion of the lattaice resistance is derived from simulations in two-dimensional hexagonal lattices with UBER force laws with a variety of shapes. Both branching cleavage and blunting emission can be described in terms of a stability diagram in the space of the remote stress intensity factors, and the competition between events on the initial cleavage plane and those on the branching plane can be described by overlays of the two appropriate stability diagrams. The popular criterion that kII=0 on the branching plane is explored for lattices and found to fail significantly, because the lattice stabilizes cleavage by the anisotropy of the surface energy. Also, in the lattice, dislocation emission must must always be considered as an alternative competing event to branching.

BPP: a sequence-based algorithm for branch point prediction.

PubMed

Zhang, Qing; Fan, Xiaodan; Wang, Yejun; Sun, Ming-An; Shao, Jianlin; Guo, Dianjing

2017-10-15

Although high-throughput sequencing methods have been proposed to identify splicing branch points in the human genome, these methods can only detect a small fraction of the branch points subject to the sequencing depth, experimental cost and the expression level of the mRNA. An accurate computational model for branch point prediction is therefore an ongoing objective in human genome research. We here propose a novel branch point prediction algorithm that utilizes information on the branch point sequence and the polypyrimidine tract. Using experimentally validated data, we demonstrate that our proposed method outperforms existing methods. Availability and implementation: https://github.com/zhqingit/BPP. djguo@cuhk.edu.hk. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Infraorbital foramen: horizontal location in relation to ala nasi.

PubMed

Takahashi, Yasuhiro; Kakizaki, Hirohiko; Nakano, Takashi

2011-01-01

To examine the horizontal location of the infraorbital foramen in relation to the ala nasi. Fifty-six orbits of 28 Japanese cadavers (18 male and 10 female cadavers; average death age, 79.7 years), fixed in 10% buffered formalin, were used. The horizontal distance from the vertical line through the lateral margin of the ala nasi to the medial margin of the infraorbital foramen (the horizontal distance) and the transverse diameter of the infraorbital foramen (the transverse diameter) were examined. Values were compared between genders and sides using Student's t test. The mean horizontal distance was 4.9 mm, with no significant difference between genders (male, 5.2 mm; female, 4.4 mm; p = 0.150) or sides (right, 4.9 mm; left, 4.9 mm; p = 0.944). The mean transverse diameter was 5.5 mm. Although there was no significant difference in this diameter between sides (right, 5.3 mm; left, 5.6 mm; p = 0.358), there was a significant difference between genders (male, 5.7 mm; female, 5.1 mm; p = 0.033). The horizontal distance had no gender difference. This value is available irrespective of gender in surgery.

Automated Tracing of Horizontal Neuron Processes During Retinal Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kerekes, Ryan A; Martins, Rodrigo; Dyer, Michael A

2011-01-01

In the developing mammalian retina, horizontal neurons undergo a dramatic reorganization oftheir processes shortly after they migrate to their appropriate laminar position. This is an importantprocess because it is now understood that the apical processes are important for establishing theregular mosaic of horizontal cells in the retina and proper reorganization during lamination isrequired for synaptogenesis with photoreceptors and bipolar neurons. However, this process isdifficult to study because the analysis of horizontal neuron anatomy is labor intensive and time-consuming. In this paper, we present a computational method for automatically tracing the three-dimensional (3-D) dendritic structure of horizontal retinal neurons in two-photonmore » laser scanningmicroscope (TPLSM) imagery. Our method is based on 3-D skeletonization and is thus able topreserve the complex structure of the dendritic arbor of these cells. We demonstrate theeffectiveness of our approach by comparing our tracing results against two sets of semi-automatedtraces over a set of 10 horizontal neurons ranging in age from P1 to P5. We observe an averageagreement level of 81% between our automated trace and the manual traces. This automatedmethod will serve as an important starting point for further refinement and optimization.« less

Effects of vertical shear in modelling horizontal oceanic dispersion

NASA Astrophysics Data System (ADS)

Lanotte, A. S.; Corrado, R.; Palatella, L.; Pizzigalli, C.; Schipa, I.; Santoleri, R.

2016-02-01

The effect of vertical shear on the horizontal dispersion properties of passive tracer particles on the continental shelf of the South Mediterranean is investigated by means of observation and model data. In situ current measurements reveal that vertical gradients of horizontal velocities in the upper mixing layer decorrelate quite fast ( ˜ 1 day), whereas an eddy-permitting ocean model, such as the Mediterranean Forecasting System, tends to overestimate such decorrelation time because of finite resolution effects. Horizontal dispersion, simulated by the Mediterranean sea Forecasting System, is mostly affected by: (1) unresolved scale motions, and mesoscale motions that are largely smoothed out at scales close to the grid spacing; (2) poorly resolved time variability in the profiles of the horizontal velocities in the upper layer. For the case study we have analysed, we show that a suitable use of deterministic kinematic parametrizations is helpful to implement realistic statistical features of tracer dispersion in two and three dimensions. The approach here suggested provides a functional tool to control the horizontal spreading of small organisms or substance concentrations, and is thus relevant for marine biology, pollutant dispersion as well as oil spill applications.

Photoelectrocatalytic activity of a hydrothermally grown branched Zno nanorod-array electrode for paracetamol degradation.

PubMed

Lin, Chin Jung; Liao, Shu-Jun; Kao, Li-Cheng; Liou, Sofia Ya Hsuan

2015-06-30

Hierarchical branched ZnO nanorod (B-ZnR) arrays as an electrode for efficient photoelectrocatalytic degradation of paracetamol were grown on fluorine-doped tin oxide substrates using a solution route. The morphologic and structural studies show the ZnO trunks are single-crystalline hexagonal wurtzite ZnO with a [0001] growth direction and are densely covered by c-axis-oriented ZnO branches. The obvious enhancement in photocurrent response of the B-ZnR electrode was obtained than that in the ZnO nanoparticle (ZnO NP) electrode. For the photoelectrocatalytic degradation of paracetamol in 20 h, the conversion fraction of the drug increased from 32% over ZnO NP electrode to 62% over B-ZnR arrays with about 3-fold increase in initial reaction rate. The light intensity-dependent photoelectrocatalytic experiment indicated that the superior performance over the B-ZnR electrode was mainly ascribed to the increased specific surface area without significantly sacrificing the charge transport and pollutant diffusion efficiencies. Two aromatic intermediate compounds were observed and eventually converted into harmless carboxylic acids and ammonia. Hierarchical tree-like ZnO arrays can be considered effective alternatives to improve photoelectro degradation rates without the need for expensive additives. Copyright © 2015 Elsevier B.V. All rights reserved.

Linking Silica Support Morphology to the Dynamics of Aminopolymers in Composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carrillo, Jan-Michael Y.; Potter, Matthew E.; Sakwa-Novak, Miles A.

A combined computational and experimental approach is used to elucidate the effect of silica support morphology on polymer dynamics and CO 2 adsorption capacities in aminopolymer/silica composites. Furthermore, simulations are based on coarse-grained molecular dynamics simulations of aminopolymer composites where a branched aminopolymer, representing poly(ethylenimine) (PEI), is impregnated into different silica mesoporous supports. The morphology of the mesoporous supports varies from hexagonally packed cylindrical pores representing SBA-15, double gyroids representing KIT-6 and MCM-48, and cagelike structures representing SBA-16. In parallel, composites of PEI and the silica supports SBA-15, KIT-6, MCM-48, and SBA-16 are synthesized and characterized, including measuring their COmore » 2 uptake. Simulations predict that a 3D pore morphology, such as those of KIT-6, MCM-48, and SBA-16, will have faster segmental mobility and have lower probability of primary amine and surface silanol associations, which should translate to higher CO 2 uptake in comparison to a 2D pore morphology such as that of SBA-15. We found that KIT-6 has higher CO 2 uptake than SBA-15 at equivalent PEI loading, even though both supports have similar surface area and pore volume. But, this is not the case for the MCM-48 support, which has smaller pores, and SBA-16, whose pore structure rapidly degrades after PEI impregnation.« less

Measurement of prominent eta-decay branching fractions.

PubMed

Lopez, A; Mehrabyan, S; Mendez, H; Ramirez, J; Ge, J Y; Miller, D H; Sanghi, B; Shipsey, I P J; Xin, B; Adams, G S; Anderson, M; Cummings, J P; Danko, I; Hu, D; Moziak, B; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Yang, F; Artuso, M; Blusk, S; Khalil, S; Li, J; Menaa, N; Mountain, R; Nisar, S; Randrianarivony, K; Sia, R; Skwarnicki, T; Stone, S; Wang, J C; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Asner, D M; Edwards, K W; Naik, P; Briere, R A; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L; Adam, N E; Alexander, J P; Cassel, D G; Duboscq, J E; Ehrlich, R; Fields, L; Galik, R S; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Mohapatra, D; Onyisi, P U E; Patterson, J R; Peterson, D; Riley, D; Ryd, A; Sadoff, A J; Shi, X; Stroiney, S; Sun, W M; Wilksen, T; Athar, S B; Patel, R; Yelton, J; Rubin, P; Eisenstein, B I; Karliner, I; Lowrey, N; Selen, M; White, E J; Wiss, J; Mitchell, R E; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Zweber, P; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A; Ernst, J; Ecklund, K M; Severini, H; Love, W; Savinov, V

2007-09-21

The decay psi(2S) --> etaJ/psi is used to measure, for the first time, all prominent eta-meson branching fractions with the same experiment in the same dataset, thereby providing a consistent treatment of systematics across branching fractions. We present results for eta decays to gamma gamma, pi(+)pi(-)pi(0), 3pi(0), pi(+)pi(-)gamma and e(+)e(-)gamma, accounting for 99.9% of all eta decays. The precision of several of the branching fractions and their ratios is improved. Two channels, pi(+)pi(-)gamma and e(+)e(-)gamma, show results that differ at the level of three standard deviations from those previously determined.

Measurement of Prominent η-Decay Branching Fractions

NASA Astrophysics Data System (ADS)

Lopez, A.; Mehrabyan, S.; Mendez, H.; Ramirez, J.; Ge, J. Y.; Miller, D. H.; Sanghi, B.; Shipsey, I. P. J.; Xin, B.; Adams, G. S.; Anderson, M.; Cummings, J. P.; Danko, I.; Hu, D.; Moziak, B.; Napolitano, J.; He, Q.; Insler, J.; Muramatsu, H.; Park, C. S.; Thorndike, E. H.; Yang, F.; Artuso, M.; Blusk, S.; Khalil, S.; Li, J.; Menaa, N.; Mountain, R.; Nisar, S.; Randrianarivony, K.; Sia, R.; Skwarnicki, T.; Stone, S.; Wang, J. C.; Bonvicini, G.; Cinabro, D.; Dubrovin, M.; Lincoln, A.; Asner, D. M.; Edwards, K. W.; Naik, P.; Briere, R. A.; Ferguson, T.; Tatishvili, G.; Vogel, H.; Watkins, M. E.; Rosner, J. L.; Adam, N. E.; Alexander, J. P.; Cassel, D. G.; Duboscq, J. E.; Ehrlich, R.; Fields, L.; Galik, R. S.; Gibbons, L.; Gray, R.; Gray, S. W.; Hartill, D. L.; Heltsley, B. K.; Hertz, D.; Jones, C. D.; Kandaswamy, J.; Kreinick, D. L.; Kuznetsov, V. E.; Mahlke-Krüger, H.; Mohapatra, D.; Onyisi, P. U. E.; Patterson, J. R.; Peterson, D.; Riley, D.; Ryd, A.; Sadoff, A. J.; Shi, X.; Stroiney, S.; Sun, W. M.; Wilksen, T.; Athar, S. B.; Patel, R.; Yelton, J.; Rubin, P.; Eisenstein, B. I.; Karliner, I.; Lowrey, N.; Selen, M.; White, E. J.; Wiss, J.; Mitchell, R. E.; Shepherd, M. R.; Besson, D.; Pedlar, T. K.; Cronin-Hennessy, D.; Gao, K. Y.; Hietala, J.; Kubota, Y.; Klein, T.; Lang, B. W.; Poling, R.; Scott, A. W.; Zweber, P.; Dobbs, S.; Metreveli, Z.; Seth, K. K.; Tomaradze, A.; Ernst, J.; Ecklund, K. M.; Severini, H.; Love, W.; Savinov, V.

2007-09-01

The decay ψ(2S)→ηJ/ψ is used to measure, for the first time, all prominent η-meson branching fractions with the same experiment in the same dataset, thereby providing a consistent treatment of systematics across branching fractions. We present results for η decays to γγ, π+π-π0, 3π0, π+π-γ and e+e-γ, accounting for 99.9% of all η decays. The precision of several of the branching fractions and their ratios is improved. Two channels, π+π-γ and e+e-γ, show results that differ at the level of three standard deviations from those previously determined.

Horizontal Running Mattress Suture Modified with Intermittent Simple Loops

PubMed Central

Chacon, Anna H; Shiman, Michael I; Strozier, Narissa; Zaiac, Martin N

2013-01-01

Using the combination of a horizontal running mattress suture with intermittent loops achieves both good eversion with the horizontal running mattress plus the ease of removal of the simple loops. This combination technique also avoids the characteristic railroad track marks that result from prolonged non-absorbable suture retention. The unique feature of our technique is the incorporation of one simple running suture after every two runs of the horizontal running mattress suture. To demonstrate its utility, we used the suturing technique on several patients and analyzed the cosmetic outcome with post-operative photographs in comparison to other suturing techniques. In summary, the combination of running horizontal mattress suture with simple intermittent loops demonstrates functional and cosmetic benefits that can be readily taught, comprehended, and employed, leading to desirable aesthetic results and wound edge eversion. PMID:23723610

Description of two species of early branching dinoflagellates, Psammosa pacifica n. g., n. sp. and P. atlantica n. sp.

PubMed

Okamoto, Noriko; Horák, Aleš; Keeling, Patrick J

2012-01-01

In alveolate evolution, dinoflagellates have developed many unique features, including the cell that has epicone and hypocone, the undulating transverse flagellum. However, it remains unclear how these features evolved. The early branching dinoflagellates so far investigated such as Hematodinium, Amoebophrya and Oxyrrhis marina differ in many ways from of core dinoflagellates, or dinokaryotes. Except those handful of well studied taxa, the vast majority of early branching dinoflagellates are known only by environmental sequences, and remain enigmatic. In this study we describe two new species of the early branching dinoflagellates, Psammosa pacifica n. g., n. sp. and P. atlantica n. sp. from marine intertidal sandy beach. Molecular phylogeny of the small subunit (SSU) ribosomal RNA and Hsp90 gene places Psammosa spp. as an early branch among the dinoflagellates. Morphologically (1) they lack the typical dinoflagellate epicone-hypocone structure, and (2) undulation in either flagella. Instead they display a mosaïc of dinokaryotes traits, i.e. (3) presence of bi-partite trychocysts; Oxyrrhis marina-like traits, i.e. (4) presence of flagellar hairs, (5) presence of two-dimensional cobweb scales ornamenting both flagella (6) transversal cell division; a trait shared with some syndineansand Parvilucifera spp. i.e. (7) a nucleus with a conspicuous nucleolus and condensed chromatin distributed beneath the nuclear envelope; as well as Perkinsus marinus -like features i.e. (8) separate ventral grooves where flagella emerge and (9) lacking dinoflagellate-type undulating flagellum. Notably Psammosa retains an apical complex structure, which is shared between perkinsids, colpodellids, chromerids and apicomplexans, but is not found in dinokaryotic dinoflagellates.

Description of Two Species of Early Branching Dinoflagellates, Psammosa pacifica n. g., n. sp. and P. atlantica n. sp

PubMed Central

Okamoto, Noriko; Horák, Aleš; Keeling, Patrick J.

2012-01-01

In alveolate evolution, dinoflagellates have developed many unique features, including the cell that has epicone and hypocone, the undulating transverse flagellum. However, it remains unclear how these features evolved. The early branching dinoflagellates so far investigated such as Hematodinium, Amoebophrya and Oxyrrhis marina differ in many ways from of core dinoflagellates, or dinokaryotes. Except those handful of well studied taxa, the vast majority of early branching dinoflagellates are known only by environmental sequences, and remain enigmatic. In this study we describe two new species of the early branching dinoflagellates, Psammosa pacifica n. g., n. sp. and P. atlantica n. sp. from marine intertidal sandy beach. Molecular phylogeny of the small subunit (SSU) ribosomal RNA and Hsp90 gene places Psammosa spp. as an early branch among the dinoflagellates. Morphologically (1) they lack the typical dinoflagellate epicone–hypocone structure, and (2) undulation in either flagella. Instead they display a mosaïc of dinokaryotes traits, i.e. (3) presence of bi-partite trychocysts; Oxyrrhis marina–like traits, i.e. (4) presence of flagellar hairs, (5) presence of two-dimensional cobweb scales ornamenting both flagella (6) transversal cell division; a trait shared with some syndineansand Parvilucifera spp. i.e. (7) a nucleus with a conspicuous nucleolus and condensed chromatin distributed beneath the nuclear envelope; as well as Perkinsus marinus -like features i.e. (8) separate ventral grooves where flagella emerge and (9) lacking dinoflagellate-type undulating flagellum. Notably Psammosa retains an apical complex structure, which is shared between perkinsids, colpodellids, chromerids and apicomplexans, but is not found in dinokaryotic dinoflagellates. PMID:22719825

Formation of fold and thrust belts on Venus due to horizontal shortening of a laterally heterogeneous lithosphere

NASA Technical Reports Server (NTRS)

Zuber, M. T.; Parmentier, E. M.; Neumann, G. A.

1994-01-01

An outstanding question relevant to understanding the tectonics of Venus is the mechanism of formation of fold and thrust belts, such as the mountain belts that surround Lakshmi Planum in western Ishtar Terra. These structures are typically long (hundreds of km) and narrow (many tens of km), and are often located at the margins of relatively high (km-scale) topographic rises. Previous studies have attempted to explain fold and thrust belts in various areas of Venus in the context of viscous and brittle wedge theory. However, while wedge theory can explain the change in elevation from the rise to the adjacent lowland, it fails to account for a fundamental aspect of the deformation, i.e., the topographic high at the edge of the rise. In this study we quantitatively explore the hypothesis that fold and thrust belt morphology on Venus can alternatively be explained by horizontal shortening of a lithosphere that is laterally heterogeneous, due either to a change in thickness of the lithosphere or the crust. Lateral heterogeneities in lithosphere structure may arise in response to thermal thinning or extensive faulting, while variations in crustal thickness may arise due to either spatially variable melting of mantle material or by horizontal shortening of the crust. In a variable thickness lithosphere or crust that is horizontally shortened, deformation will tend to localize in the vicinity of thickness heterogeneity, resulting in a higher component of dynamic topography there as compared to elsewhere in the shortening lithosphere. This mechanism may thus provide a simple explanation for the topographic high at the edge of the rise.

Formation of fold and thrust belts on Venus due to horizontal shortening of a laterally heterogeneous lithosphere

NASA Astrophysics Data System (ADS)

Zuber, M. T.; Parmentier, E. M.; Neumann, G. A.

1994-03-01

An outstanding question relevant to understanding the tectonics of Venus is the mechanism of formation of fold and thrust belts, such as the mountain belts that surround Lakshmi Planum in western Ishtar Terra. These structures are typically long (hundreds of km) and narrow (many tens of km), and are often located at the margins of relatively high (km-scale) topographic rises. Previous studies have attempted to explain fold and thrust belts in various areas of Venus in the context of viscous and brittle wedge theory. However, while wedge theory can explain the change in elevation from the rise to the adjacent lowland, it fails to account for a fundamental aspect of the deformation, i.e., the topographic high at the edge of the rise. In this study we quantitatively explore the hypothesis that fold and thrust belt morphology on Venus can alternatively be explained by horizontal shortening of a lithosphere that is laterally heterogeneous, due either to a change in thickness of the lithosphere or the crust. Lateral heterogeneities in lithosphere structure may arise in response to thermal thinning or extensive faulting, while variations in crustal thickness may arise due to either spatially variable melting of mantle material or by horizontal shortening of the crust. In a variable thickness lithosphere or crust that is horizontally shortened, deformation will tend to localize in the vicinity of thickness heterogeneity, resulting in a higher component of dynamic topography there as compared to elsewhere in the shortening lithosphere. This mechanism may thus provide a simple explanation for the topographic high at the edge of the rise.

Uncertainty and probability for branching selves

NASA Astrophysics Data System (ADS)

Lewis, Peter J.

Everettian accounts of quantum mechanics entail that people branch; every possible result of a measurement actually occurs, and I have one successor for each result. Is there room for probability in such an account? The prima facie answer is no; there are no ontic chances here, and no ignorance about what will happen. But since any adequate quantum mechanical theory must make probabilistic predictions, much recent philosophical labor has gone into trying to construct an account of probability for branching selves. One popular strategy involves arguing that branching selves introduce a new kind of subjective uncertainty. I argue here that the variants of this strategy in the literature all fail, either because the uncertainty is spurious, or because it is in the wrong place to yield probabilistic predictions. I conclude that uncertainty cannot be the ground for probability in Everettian quantum mechanics.

Comparison of radiological and morphologic assessments of myocardial bridges.

PubMed

Ercakmak, Burcu; Bulut, Elif; Hayran, Mutlu; Kaymaz, Figen; Bilgin, Selma; Hazirolan, Tuncay; Bayramoglu, Alp; Erbil, Mine

2015-09-01

In this study we aimed to compare the findings of coronary dual-source computed tomography angiography of myocardial bridges with cadaveric dissections. Forty-one isolated, non-damaged fresh sheep hearts were used in this study. Myocardial bridges of the anterior interventricular branch of the left coronary artery were demonstrated and analyzed by a coronary dual-source computed tomography angiography. Dissections along the left anterior interventricular branch of the left coronary artery were performed by using Zeiss OPMI pico microscope and the length of the bridges were measured. The depths of the myocardial bridges were measured from the stained sections by using the light microscope (Leica DM 6000B). MBs were found in all 41 hearts (100%) during dissections. Dual-source computed tomography angiography successfully detected 87.8% (36 of the 41 hearts) of the myocardial bridges measured on left anterior interventricular branch of left coronary artery. The lengths of the myocardial bridges were found 5-40 and 8-50 mm with dissection and dual-source computed tomography angiography, respectively. And the depths were found 0.7-4.5 mm by dual-source computed tomography angiography and 0.745-4.632 mm morphologically. Comparison of the mean values of the lengths showed statistically significantly higher values (22.0 ± 8.5, 17.7 ± 7.7 mm, p = 0.003) for the dissections. Radiological assessment also effectively discriminated complete bridges from incomplete ones. Our study showed that coronary computed tomography angiography is reliable in evaluating the presence and depth of myocardial bridges.

Anomalous sylvian fissure morphology in Williams syndrome.

PubMed

Eckert, Mark A; Galaburda, Albert M; Karchemskiy, Asya; Liang, Alyssa; Thompson, Paul; Dutton, Rebecca A; Lee, Agatha D; Bellugi, Ursula; Korenberg, Julie R; Mills, Debra; Rose, Fredric E; Reiss, Allan L

2006-10-15

The unusual sensitivity and attraction to auditory stimuli in people with Williams syndrome (WS) has been hypothesized to be the consequence of atypical development of brain regions surrounding the Sylvian fissure. Planum temporale surface area, which is determined in part by Sylvian fissure patterning, was examined in 42 WS and 40 control participants to determine if anomalous Sylvian fissure morphology is present in WS. WS participants had significantly reduced leftward asymmetry of the planum temporale compared to control participants, due to a significant expansion in the size of the right planum temporale. The increased right planum temporale size was largely due to WS participants (24%) who had a right hemisphere Sylvian fissure that coursed horizontally and failed to ascend into the parietal lobe. This sulcal pattern is unusual in the right hemisphere and is more commonly found in the left hemisphere of typically developing individuals. There were no control participants with this type of right hemisphere Sylvian fissure pattern. The right hemisphere Sylvian fissure sulcal patterns were also related to a measure of cortical complexity and the amount of right hemisphere occipital lobe volume, suggesting that intrinsic genetic influences leading to anomalous visual system development in WS have widespread influences on cortical morphology that are similar in manner to extrinsic embryonic visual system lesions.

ULTRAVIOLET PROPERTIES OF GALACTIC GLOBULAR CLUSTERS WITH GALEX. II. INTEGRATED COLORS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dalessandro, Emanuele; Ferraro, Francesco R.; Lanzoni, Barbara

2012-11-01

We present ultraviolet (UV) integrated colors of 44 Galactic globular clusters (GGCs) observed with the Galaxy Evolution Explorer (GALEX) in both FUV and NUV bands. This database is the largest homogeneous catalog of UV colors ever published for stellar systems in our Galaxy. The proximity of GGCs makes it possible to resolve many individual stars even with the somewhat low spatial resolution of GALEX. This allows us to determine how the integrated UV colors are driven by hot stellar populations, primarily horizontal branch stars and their progeny. The UV colors are found to be correlated with various parameters commonly usedmore » to define the horizontal branch morphology. We also investigate how the UV colors vary with parameters like metallicity, age, helium abundance, and concentration. We find for the first time that GCs associated with the Sagittarius dwarf galaxy have (FUV - V) colors systematically redder than GGCs with the same metallicity. Finally, we speculate about the presence of an interesting trend, suggesting that the UV color of GCs may be correlated with the mass of the host galaxy, in the sense that more massive galaxies possess bluer clusters.« less

Evaluation of horizontal curve design

DOT National Transportation Integrated Search

1980-08-01

This report documents an initial evaluation of horizontal curve design criteria which involved two phases: an observational study and an analytical evaluation. Three classes of vehicles (automobiles, school buses and tractor semi-trailers) and three ...

Dendrimers and methods of preparing same through proportionate branching

DOEpatents

Yu, Yihua; Yue, Xuyi

2015-09-15

The present invention provides for monodispersed dendrimers having a core, branches and periphery ends, wherein the number of branches increases exponentially from the core to the periphery end and the length of the branches increases exponentially from the periphery end to the core, thereby providing for attachment of chemical species at the periphery ends without exhibiting steric hindrance.

Cervical vertebrae maturation method morphologic criteria: poor reproducibility.

PubMed

Nestman, Trenton S; Marshall, Steven D; Qian, Fang; Holton, Nathan; Franciscus, Robert G; Southard, Thomas E

2011-08-01

The cervical vertebrae maturation (CVM) method has been advocated as a predictor of peak mandibular growth. A careful review of the literature showed potential methodologic errors that might influence the high reported reproducibility of the CVM method, and we recently established that the reproducibility of the CVM method was poor when these potential errors were eliminated. The purpose of this study was to further investigate the reproducibility of the individual vertebral patterns. In other words, the purpose was to determine which of the individual CVM vertebral patterns could be classified reliably and which could not. Ten practicing orthodontists, trained in the CVM method, evaluated the morphology of cervical vertebrae C2 through C4 from 30 cephalometric radiographs using questions based on the CVM method. The Fleiss kappa statistic was used to assess interobserver agreement when evaluating each cervical vertebrae morphology question for each subject. The Kendall coefficient of concordance was used to assess the level of interobserver agreement when determining a "derived CVM stage" for each subject. Interobserver agreement was high for assessment of the lower borders of C2, C3, and C4 that were either flat or curved in the CVM method, but interobserver agreement was low for assessment of the vertebral bodies of C3 and C4 when they were either trapezoidal, rectangular horizontal, square, or rectangular vertical; this led to the overall poor reproducibility of the CVM method. These findings were reflected in the Fleiss kappa statistic. Furthermore, nearly 30% of the time, individual morphologic criteria could not be combined to generate a final CVM stage because of incompatible responses to the 5 questions. Intraobserver agreement in this study was only 62%, on average, when the inconclusive stagings were excluded as disagreements. Intraobserver agreement was worse (44%) when the inconclusive stagings were included as disagreements. For the group of subjects

On extreme events for non-spatial and spatial branching Brownian motions

NASA Astrophysics Data System (ADS)

Avan, Jean; Grosjean, Nicolas; Huillet, Thierry

2015-04-01

We study the impact of having a non-spatial branching mechanism with infinite variance on some parameters (height, width and first hitting time) of an underlying Bienaymé-Galton-Watson branching process. Aiming at providing a comparative study of the spread of an epidemics whose dynamics is given by the modulus of a branching Brownian motion (BBM) we then consider spatial branching processes in dimension d, not necessarily integer. The underlying branching mechanism is either a binary branching model or one presenting infinite variance. In particular we evaluate the chance p(x) of being hit if the epidemics started away at distance x. We compute the large x tail probabilities of this event, both when the branching mechanism is regular and when it exhibits very large fluctuations.

Idiopathic accelerated idioventricular rhythm or ventricular tachycardia originating from the right bundle branch: unusual type of ventricular arrhythmia.

PubMed

Chen, Minglong; Gu, Kai; Yang, Bing; Chen, Hongwu; Ju, Weizhu; Zhang, Fengxiang; Yang, Gang; Li, Mingfang; Lu, Xinzheng; Cao, Kejiang; Ouyang, Feifan

2014-12-01

Accelerated idioventricular rhythm (AIVR) or ventricular tachycardia (VT) originating from the right bundle branch (RBB) is rare and published clinical data on such arrhythmia are scarce. In this study, we will describe the clinical manifestations, diagnosis, and management of a cohort of patients with this novel arrhythmia. Eight patients (5 men; median age, 25 years) with RBB-AIVR/VT were consecutively enrolled in the study. Pharmacological testing, exercise treadmill testing, electrophysiological study, and catheter ablation were performed in the study patients, and ECG features were characterized. All RBB-AIVR/VTs were of typical left bundle-branch block morphology with atrioventricular dissociation. The arrhythmias, which demonstrated chronotropic variability, were often isorhythmic with sinus rhythm and were accelerated by physical exercise, stress, and intravenous isoprenaline infusion. The rate of RBB-AIVR/VT varied from 45 to 200 beats per minute. Two patients experienced syncope, and 3 had impaired left ventricular function. Metoprolol was proven to be the most effective drug to decelerate the arrhythmia rate and relieve symptoms. Electrophysiology study was performed in 5 patients and the earliest activation with a sharp RBB potential was localized in the mid or distal RBB area. Catheter ablation terminated the arrhythmia with subsequent RBB block morphology during sinus rhythm. During follow-up, patients' symptoms were controlled with normalization of left ventricular function either on metoprolol or by catheter ablation. RBB-AIVR/VT is an unusual type of ventricular arrhythmia. It can result in significant symptoms and depressed ventricular function and can be successfully treated with catheter ablation. © 2014 American Heart Association, Inc.

Avoiding Steric Congestion in Dendrimer Growth through Proportionate Branching. A Twist on da Vinci's Rule of Tree Branching

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yue, Xuyi; Taraban, Marc B.; Hyland, Laura L.

2012-10-05

In making defect-free macromolecules, the challenge occurs during chemical synthesis. This challenge is especially pronounced in dendrimer synthesis where exponential growth quickly leads to steric congestion. To overcome this difficulty, proportionate branching in dendrimer growth is proposed. In proportionate branching, both the number and the length of branches increase exponentially but in opposite directions to mimic tree growth. The effectiveness of this strategy is demonstrated through the synthesis of a fluorocarbon dendron containing 243 chemically identical fluorine atoms with a MW of 9082 Da. Monodispersity is confirmed by nuclear magnetic resonance spectroscopy, mass spectrometry, and small-angle X-ray scattering. Moreover, growingmore » different parts proportionately, as nature does, could be a general strategy to achieve defect-free synthesis of macromolecules.« less

Processing woody biomass with a modified horizontal grinder

Treesearch

Dana Mitchell; John Klepac

2008-01-01

This study documents the production rate and cost of producing woody biomass chips for use in a power plant. The power plant has specific raw material handling requirements. Output from a 3-knife chipper, a tub grinder, and a horizontal grinder was considered. None of the samples from these machines met the specifications needed. A horizontal grinder was modified to...