NSGIC Local Govt | GIS Inventory — The WCSZipcode polygon feature class was created by Miami-Dade Enterprise Technology Department to be used in the WCS batch jobs to assign the actual zip code of...
Berke, Ethan M; Shi, Xun
2009-04-29
Travel time is an important metric of geographic access to health care. We compared strategies of estimating travel times when only subject ZIP code data were available. Using simulated data from New Hampshire and Arizona, we estimated travel times to nearest cancer centers by using: 1) geometric centroid of ZIP code polygons as origins, 2) population centroids as origin, 3) service area rings around each cancer center, assigning subjects to rings by assuming they are evenly distributed within their ZIP code, 4) service area rings around each center, assuming the subjects follow the population distribution within the ZIP code. We used travel times based on street addresses as true values to validate estimates. Population-based methods have smaller errors than geometry-based methods. Within categories (geometry or population), centroid and service area methods have similar errors. Errors are smaller in urban areas than in rural areas. Population-based methods are superior to the geometry-based methods, with the population centroid method appearing to be the best choice for estimating travel time. Estimates in rural areas are less reliable.
Vermont Center for Geographic Information — (Link to Metadata) A ZIP Code Tabulation Area (ZCTA) is a statistical geographic entity that approximates the delivery area for a U.S. Postal Service five-digit...
Geographic data: Zip Codes (Shape File)
Montgomery County of Maryland — This dataset contains all zip codes in Montgomery County. Zip codes are the postal delivery areas defined by USPS. Zip codes with mailboxes only are not included. As...
Allegheny County Zip Code Boundaries
Allegheny County / City of Pittsburgh / Western PA Regional Data Center — This dataset demarcates the zip code boundaries that lie within Allegheny County.If viewing this description on the Western Pennsylvania Regional Data Center’s open...
Recipients of Excess Food by Zip Code, US and Territories, 2015, EPA Region 9
U.S. Environmental Protection Agency — This GIS dataset contains polygon features that represent generalized USPS 5-digit zip code boundaries for the US and its territories. Data is licensed to US EPA by...
Efficient Proximity Computation Techniques Using ZIP Code Data for Smart Cities †
Directory of Open Access Journals (Sweden)
Muhammad Harist Murdani
2018-03-01
Full Text Available In this paper, we are interested in computing ZIP code proximity from two perspectives, proximity between two ZIP codes (Ad-Hoc and neighborhood proximity (Top-K. Such a computation can be used for ZIP code-based target marketing as one of the smart city applications. A naïve approach to this computation is the usage of the distance between ZIP codes. We redefine a distance metric combining the centroid distance with the intersecting road network between ZIP codes by using a weighted sum method. Furthermore, we prove that the results of our combined approach conform to the characteristics of distance measurement. We have proposed a general and heuristic approach for computing Ad-Hoc proximity, while for computing Top-K proximity, we have proposed a general approach only. Our experimental results indicate that our approaches are verifiable and effective in reducing the execution time and search space.
Efficient Proximity Computation Techniques Using ZIP Code Data for Smart Cities †.
Murdani, Muhammad Harist; Kwon, Joonho; Choi, Yoon-Ho; Hong, Bonghee
2018-03-24
In this paper, we are interested in computing ZIP code proximity from two perspectives, proximity between two ZIP codes ( Ad-Hoc ) and neighborhood proximity ( Top-K ). Such a computation can be used for ZIP code-based target marketing as one of the smart city applications. A naïve approach to this computation is the usage of the distance between ZIP codes. We redefine a distance metric combining the centroid distance with the intersecting road network between ZIP codes by using a weighted sum method. Furthermore, we prove that the results of our combined approach conform to the characteristics of distance measurement. We have proposed a general and heuristic approach for computing Ad-Hoc proximity, while for computing Top-K proximity, we have proposed a general approach only. Our experimental results indicate that our approaches are verifiable and effective in reducing the execution time and search space.
Determining Market Categorization of United States Zip Codes for Purposes of Army Recruiting
2016-06-01
Army uses commercial market segmentation data to analyze markets and past accessions to assign recruiters and quotas to maximize production. We use...Army Recruiting Command to rely on proprietary data with 66 market segments per ZIP code for market analysis and predicting recruiting potential...have different densities of potential recruits; the Army uses commercial market segmentation data to analyze markets and past accessions to assign
Directory of Open Access Journals (Sweden)
Ruth Link-Gelles
2016-12-01
Full Text Available In 2010, 13-valent pneumococcal conjugate vaccine (PCV13 was introduced in the US for prevention of invasive pneumococcal disease in children. Individual-level socioeconomic status (SES is a potential confounder of the estimated effectiveness of PCV13 and is often controlled for in observational studies using zip code as a proxy. We assessed the utility of zip code matching for control of SES in a post-licensure evaluation of the effectiveness of PCV13 (calculated as [1-matched odds ratio]*100. We used a directed acyclic graph to identify subsets of confounders and collected SES variables from birth certificates, geocoding, a parent interview, and follow-up with medical providers. Cases tended to be more affluent than eligible controls (for example, 48.3% of cases had private insurance vs. 44.6% of eligible controls, but less affluent than enrolled controls (52.9% of whom had private insurance. Control of confounding subsets, however, did not result in a meaningful change in estimated vaccine effectiveness (original estimate: 85.1%, 95% CI 74.8–91.9%; adjusted estimate: 82.5%, 95% CI 65.6–91.1%. In the context of a post-licensure vaccine effectiveness study, zip code appears to be an adequate, though not perfect, proxy for individual SES. Keywords: Socioeconomic status, PCV13, Pneumococcus, Pneumococcal vaccine, Vaccine effectiveness, Matched case-control
Wang, Yueyan; Ponce, Ninez A; Wang, Pan; Opsomer, Jean D; Yu, Hongjian
2015-12-01
We propose a method to meet challenges in generating health estimates for granular geographic areas in which the survey sample size is extremely small. Our generalized linear mixed model predicts health outcomes using both individual-level and neighborhood-level predictors. The model's feature of nonparametric smoothing function on neighborhood-level variables better captures the association between neighborhood environment and the outcome. Using 2011 to 2012 data from the California Health Interview Survey, we demonstrate an empirical application of this method to estimate the fraction of residents without health insurance for Zip Code Tabulation Areas (ZCTAs). Our method generated stable estimates of uninsurance for 1519 of 1765 ZCTAs (86%) in California. For some areas with great socioeconomic diversity across adjacent neighborhoods, such as Los Angeles County, the modeled uninsured estimates revealed much heterogeneity among geographically adjacent ZCTAs. The proposed method can increase the value of health surveys by providing modeled estimates for health data at a granular geographic level. It can account for variations in health outcomes at the neighborhood level as a result of both socioeconomic characteristics and geographic locations.
Office of Personnel Management — The system used to associate what Federal Employees Health Benefits Program (FEHBP) and Federal Employees Dental/Vision Program (FEDVIP) health, dental, and vision...
Directory of Open Access Journals (Sweden)
Puett Robin C
2009-10-01
Full Text Available Abstract Background There is increasing interest in the study of place effects on health, facilitated in part by geographic information systems. Incomplete or missing address information reduces geocoding success. Several geographic imputation methods have been suggested to overcome this limitation. Accuracy evaluation of these methods can be focused at the level of individuals and at higher group-levels (e.g., spatial distribution. Methods We evaluated the accuracy of eight geo-imputation methods for address allocation from ZIP codes to census tracts at the individual and group level. The spatial apportioning approaches underlying the imputation methods included four fixed (deterministic and four random (stochastic allocation methods using land area, total population, population under age 20, and race/ethnicity as weighting factors. Data included more than 2,000 geocoded cases of diabetes mellitus among youth aged 0-19 in four U.S. regions. The imputed distribution of cases across tracts was compared to the true distribution using a chi-squared statistic. Results At the individual level, population-weighted (total or under age 20 fixed allocation showed the greatest level of accuracy, with correct census tract assignments averaging 30.01% across all regions, followed by the race/ethnicity-weighted random method (23.83%. The true distribution of cases across census tracts was that 58.2% of tracts exhibited no cases, 26.2% had one case, 9.5% had two cases, and less than 3% had three or more. This distribution was best captured by random allocation methods, with no significant differences (p-value > 0.90. However, significant differences in distributions based on fixed allocation methods were found (p-value Conclusion Fixed imputation methods seemed to yield greatest accuracy at the individual level, suggesting use for studies on area-level environmental exposures. Fixed methods result in artificial clusters in single census tracts. For studies
Directory of Open Access Journals (Sweden)
Azadeh Ahkamiraad
2018-03-01
Full Text Available Current power grids in many countries are not fully prepared for high electric vehicle (EV penetration, and there is evidence that the construction of additional grid capacity is constantly outpaced by EV diffusion. If this situation continues, then it will compromise grid reliability and cause problems such as system overload, voltage and frequency fluctuations, and power losses. This is especially true for densely populated areas where the grid capacity is already strained with existing old infrastructure. The objective of this research is to identify the zip-code level electricity consumption that is associated with large-scale EV adoption in New York City, one of the most densely populated areas in the United States (U.S.. We fuse the Fisher and Pry diffusion model and Rogers model within the agent-based simulation to forecast zip-code level EV diffusion and the required energy capacity to satisfy the charging demand. The research outcomes will assist policy makers and grid operators in making better planning decisions on the locations and timing of investments during the transition to smarter grids and greener transportation.
Linton, Sabriya L; Cooper, Hannah Lf; Kelley, Mary E; Karnes, Conny C; Ross, Zev; Wolfe, Mary E; Friedman, Samuel R; Jarlais, Don Des; Semaan, Salaam; Tempalski, Barbara; Sionean, Catlainn; DiNenno, Elizabeth; Wejnert, Cyprian; Paz-Bailey, Gabriela
2017-06-20
Housing instability has been associated with poor health outcomes among people who inject drugs (PWID). This study investigates the associations of local-level housing and economic conditions with homelessness among a large sample of PWID, which is an underexplored topic to date. PWID in this cross-sectional study were recruited from 19 large cities in the USA as part of National HIV Behavioral Surveillance. PWID provided self-reported information on demographics, behaviours and life events. Homelessness was defined as residing on the street, in a shelter, in a single room occupancy hotel, or in a car or temporarily residing with friends or relatives any time in the past year. Data on county-level rental housing unaffordability and demand for assisted housing units, and ZIP code-level gentrification (eg, index of percent increases in non-Hispanic white residents, household income, gross rent from 1990 to 2009) and economic deprivation were collected from the US Census Bureau and Department of Housing and Urban Development. Multilevel models evaluated the associations of local economic and housing characteristics with homelessness. Sixty percent (5394/8992) of the participants reported homelessness in the past year. The multivariable model demonstrated that PWID living in ZIP codes with higher levels of gentrification had higher odds of homelessness in the past year (gentrification: adjusted OR=1.11, 95% CI=1.04 to 1.17). Additional research is needed to determine the mechanisms through which gentrification increases homelessness among PWID to develop appropriate community-level interventions. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.
International Nuclear Information System (INIS)
Sumner, H.M.
1969-03-01
The KDF9/EGDON program ZIP MK 2 is the third of a series of programs for off-line digital computer analysis of dynamic systems: it has been designed specifically to cater for the needs of the design or control engineer in having an input scheme which is minimally computer-oriented. It uses numerical algorithms which are as near fool-proof as the author could discover or devise, and has comprehensive diagnostic sections to help the user in the event of faulty data or machine execution. ZIP MK 2 accepts mathematical models comprising first order linear differential and linear algebraic equations, and from these computes and factorises the transfer functions between specified pairs of output and input variables; if desired, the frequency response may be computed from the computed transfer function. The model input scheme is fully compatible with the frequency response programs FRP MK 1 and MK 2, except that, for ZIP MK 2, transport, or time-delays must be converted by the user to Pade or Bode approximations prior to input. ZIP provides the pole-zero plot, (or complex plane analysis), while FRP provides the frequency response and FIFI the time domain analyses. The pole-zero method of analysis has been little used in the past for complex models, especially where transport delays occur, and one of its primary purposes is as a research tool to investigate the usefulness of this method, for process plant, whether nuclear, chemical or other continuous processes. (author)
2004-01-01
16 January 2004 Looking somewhat like a roadmap, this 3 km (1.9 mi) wide view of a cratered plain in the martian south polar region shows a plethora of cracks that form polygonal patterns. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image is located near 78.9oS, 357.3oW. Polygons such as these, where they are found on Earth, would be indicators of the presence of subsurface ice. Whether the same is true for Mars is uncertain. What is certain is that modern, seasonal frost on the surface enhances the appearance of the polygons as the frost persists longer in the cracks than on adjacent plains. This southern springtime image is illuminated by sunlight from the upper left.
2005-01-01
18 August 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark-outlined polygons on a frost-covered surface in the south polar region of Mars. In summer, this surface would not be bright and the polygons would not have dark outlines--these are a product of the presence of seasonal frost. Location near: 77.2oS, 204.8oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring
Maldeghem, Hendrik
1998-01-01
This book is intended to be an introduction to the fascinating theory ofgeneralized polygons for both the graduate student and the specialized researcher in the field. It gathers together a lot of basic properties (some of which are usually referred to in research papers as belonging to folklore) and very recent and sometimes deep results. I have chosen a fairly strict geometrical approach, which requires some knowledge of basic projective geometry. Yet, it enables one to prove some typically group-theoretical results such as the determination of the automorphism groups of certain Moufang polygons. As such, some basic group-theoretical knowledge is required of the reader. The notion of a generalized polygon is a relatively recent one. But it is one of the most important concepts in incidence geometry. Generalized polygons are the building bricks of Tits buildings. They are the prototypes and precursors of more general geometries such as partial geometries, partial quadrangles, semi-partial ge ometries, near...
Van Maldeghem, Hendrik
1998-01-01
Generalized Polygons is the first book to cover, in a coherent manner, the theory of polygons from scratch. In particular, it fills elementary gaps in the literature and gives an up-to-date account of current research in this area, including most proofs, which are often unified and streamlined in comparison to the versions generally known. Generalized Polygons will be welcomed both by the student seeking an introduction to the subject as well as the researcher who will value the work as a reference. In particular, it will be of great value for specialists working in the field of generalized polygons (which are, incidentally, the rank 2 Tits-buildings) or in fields directly related to Tits-buildings, incidence geometry and finite geometry. The approach taken in the book is of geometric nature, but algebraic results are included and proven (in a geometric way!). A noteworthy feature is that the book unifies and generalizes notions, definitions and results that exist for quadrangles, hexagons, octagons - in the ...
International Nuclear Information System (INIS)
2000-01-01
In Russian, ''The Polygon'' stands for a nuclear test site of 19.000 square kilometers in Kazakhstan, used by the former Soviet Union for hundreds of nuclear tests from 1947 to 1991. This film looks at the legacy of what was once a top secret area, now abandoned, but still sparsely populated, and at the work to be done to detect and map the areas of elevated radiation levels
Lu, Yanyan; Lien, Jyh-Ming; Ghosh, Mukulika; Amato, Nancy M.
2012-01-01
Decomposing a shape into visually meaningful parts comes naturally to humans, but recreating this fundamental operation in computers has been shown to be difficult. Similar challenges have puzzled researchers in shape reconstruction for decades. In this paper, we recognize the strong connection between shape reconstruction and shape decomposition at a fundamental level and propose a method called α-decomposition. The α-decomposition generates a space of decompositions parameterized by α, the diameter of a circle convolved with the input polygon. As we vary the value of α, some structural features appear and disappear quickly while others persist. Therefore, by analyzing the persistence of the features, we can determine better decompositions that are more robust to both geometrical and topological noises. © 2012 Elsevier Ltd. All rights reserved.
Lu, Yanyan
2012-08-01
Decomposing a shape into visually meaningful parts comes naturally to humans, but recreating this fundamental operation in computers has been shown to be difficult. Similar challenges have puzzled researchers in shape reconstruction for decades. In this paper, we recognize the strong connection between shape reconstruction and shape decomposition at a fundamental level and propose a method called α-decomposition. The α-decomposition generates a space of decompositions parameterized by α, the diameter of a circle convolved with the input polygon. As we vary the value of α, some structural features appear and disappear quickly while others persist. Therefore, by analyzing the persistence of the features, we can determine better decompositions that are more robust to both geometrical and topological noises. © 2012 Elsevier Ltd. All rights reserved.
Scott, Paul
2006-01-01
A "convex" polygon is one with no re-entrant angles. Alternatively one can use the standard convexity definition, asserting that for any two points of the convex polygon, the line segment joining them is contained completely within the polygon. In this article, the author provides a solution to a problem involving convex lattice polygons.
Stephenson, Paul
2009-01-01
In order to find its circumference, Archimedes famously boxed the circle between two polygons. Ending the first of a series of articles (MT179) with an aside, Francis Lopez-Real reverses the situation to ask: Which polygons can be boxed between two circles? (The official term for such polygons is "bicentric".) The sides of these polygons are…
Colleu , Thomas; Morin , Luce; Pateux , Stéphane; Labit , Claude
2011-01-01
International audience; This paper presents a new representation called floating polygon soup for applications like 3DTV and FTV (Free Viewpoint Television). This representation is based on 3D polygons and takes as input MVD data. It extends the previously proposed polygon soup representation which is appropriate for both compression, transmission and rendering stages. The floating polygon soup conserves these advantages while also taking into account misalignments at the view synthesis stage...
Scott, Paul
2006-01-01
A lattice is a (rectangular) grid of points, usually pictured as occurring at the intersections of two orthogonal sets of parallel, equally spaced lines. Polygons that have lattice points as vertices are called lattice polygons. It is clear that lattice polygons come in various shapes and sizes. A very small lattice triangle may cover just 3…
Aichholzer, Oswin; Aurenhammer, Franz; Hurtado Díaz, Fernando Alfredo; Ramos, Pedro A.; Urrutia, J.
2009-01-01
We introduce a notion of k-convexity and explore some properties of polygons that have this property. In particular, 2-convex polygons can be recognized in O(n log n) time, and k-convex polygons can be triangulated in O(kn) time.
Ergodicity of polygonal slap maps
International Nuclear Information System (INIS)
Del Magno, Gianluigi; Pedro Gaivão, José; Lopes Dias, João; Duarte, Pedro
2014-01-01
Polygonal slap maps are piecewise affine expanding maps of the interval obtained by projecting the sides of a polygon along their normals onto the perimeter of the polygon. These maps arise in the study of polygonal billiards with non-specular reflection laws. We study the absolutely continuous invariant probabilities (acips) of the slap maps for several polygons, including regular polygons and triangles. We also present a general method for constructing polygons with slap maps with more than one ergodic acip. (paper)
Knotting in stretched polygons
International Nuclear Information System (INIS)
Rensburg, E J Janse van; Orlandini, E; Tesi, M C; Whittington, S G
2008-01-01
The knotting in a lattice polygon model of ring polymers is examined when a stretching force is applied to the polygon. By examining the incidence of cut-planes in the polygon, we prove a pattern theorem in the stretching regime for large applied forces. This theorem can be used to examine the incidence of entanglements such as knotting and writhing. In particular, we prove that for arbitrarily large positive, but finite, values of the stretching force, the probability that a stretched polygon is knotted approaches 1 as the length of the polygon increases. In the case of writhing, we prove that for stretched polygons of length n, and for every function f(n)=o(√n), the probability that the absolute value of the mean writhe is less than f(n) approaches 0 as n → ∞, for sufficiently large values of the applied stretching force
Atmospheres of polygons and knotted polygons
International Nuclear Information System (INIS)
Janse Rensburg, E J Janse; Rechnitzer, A
2008-01-01
In this paper we define two statistics a + (ω) and a - (ω), the positive and negative atmospheres of a lattice polygon ω of fixed length n. These statistics have the property that (a + (ω))/(a - (ω)) = p n+2 /p n , where p n is the number of polygons of length n, counted modulo translations. We use the pivot algorithm to sample polygons and to compute the corresponding average atmospheres. Using these data, we directly estimate the growth constants of polygons in two and three dimensions. We find that μ=2.63805±0.00012 in two dimensions and μ=4.683980±0.000042±0.000067 in three dimensions, where the error bars are 67% confidence intervals, and the second error bar in the three-dimensional estimate of μ is an estimated systematic error. We also compute atmospheres of polygons of fixed knot type K sampled by the BFACF algorithm. We discuss the implications of our results and show that different knot types have atmospheres which behave dramatically differently at small values of n
Homotopic Polygonal Line Simplification
DEFF Research Database (Denmark)
Deleuran, Lasse Kosetski
This thesis presents three contributions to the area of polygonal line simplification, or simply line simplification. A polygonal path, or simply a path is a list of points with line segments between the points. A path can be simplified by morphing it in order to minimize some objective function...
2003-01-01
MGS MOC Release No. MOC2-357, 11 May 2003This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) picture shows a pattern of polygons on the floor of a northern plains impact crater. These landforms are common on crater floors at high latitudes on Mars. Similar polygons occur in the arctic and antarctic regions of Earth, where they indicate the presence and freeze-thaw cycling of ground ice. Whether the polygons on Mars also indicate water ice in the ground is uncertain. The image is located in a crater at 64.8oN, 292.7oW. Sunlight illuminates the scene from the lower left.
2003-01-01
MGS MOC Release No. MOC2-564, 4 December 2003This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows patterned ground, arranged in the form of polygons, on the undulating plains associated with ejecta from the Lyot impact crater on the martian northern plains. This picture was acquired in October 2003 and shows that the polygon margins are ridges with large boulders--shown here as dark dots--on them. On Earth, polygon patterns like this are created in arctic and antarctic regions where there is ice in the ground. The seasonal and longer-term cycles of freezing and thawing of the ice-rich ground cause these features to form over time. Whether the same is true for Mars is unknown. The polygons are located near 54.6oN, 326.6oW. The image covers an area 3 km (1.9 mi) wide and is illuminated from the lower left.
2005-01-01
26 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows polygonal patterned ground on a south high-latitude plain. The outlines of the polygons, like the craters and hills in this region, are somewhat enhanced by the presence of bright frost left over from the previous winter. On Earth, polygons at high latitudes would usually be attributed to the seasonal freezing and thawing cycles of ground ice. The origin of similar polygons on Mars is less certain, but might also be an indicator of ground ice. Location near: 75.3oS, 113.2oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring
FEMA DFIRM Panel Scheme Polygons
Minnesota Department of Natural Resources — This layer contains information about the Flood Insurance Rate Map (FIRM) panel areas. The spatial entities representing FIRM panels are polygons. The polygon for...
Near polygons and Fischer spaces
Brouwer, A.E.; Cohen, A.M.; Hall, J.I.; Wilbrink, H.A.
1994-01-01
In this paper we exploit the relations between near polygons with lines of size 3 and Fischer spaces to classify near hexagons with quads and with lines of size three. We also construct some infinite families of near polygons.
2005-01-01
3 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows polygons enhanced by subliming seasonal frost in the martian south polar region. Polygons similar to these occur in frozen ground at high latitudes on Earth, suggesting that perhaps their presence on Mars is also a sign that there is or once was ice in the shallow subsurface. The circular features are degraded meteor impact craters. Location near: 72.2oS, 310.3oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring
Automatic Sequences and Zip-Specifications
Grabmayer, C.A.; Endrullis, J.; Hendriks, D.; Klop, J.W.; Moss, L.S.
2012-01-01
We consider infinite sequences of symbols, also known as streams, and the decidability question for equality of streams defined in a restricted format. This restricted format consists of prefixing a symbol at the head of a stream, of the stream function `zip', and recursion variables. Here `zip'
Nanopatterning by molecular polygons.
Jester, Stefan-S; Sigmund, Eva; Höger, Sigurd
2011-07-27
Molecular polygons with three to six sides and binary mixtures thereof form long-range ordered patterns at the TCB/HOPG interface. This includes also the 2D crystallization of pentagons. The results provide an insight into how the symmetry of molecules is translated into periodic structures.
2002-01-01
[figure removed for brevity, see original site] This jumble of eroded ridges and mesas occurs within Ares Vallis, one of the largest catastrophic outflow channels on the planet. Floods raged through this channel, portions of which are up to 25 km wide, pouring out into the Chryse Basin to the north. Close inspection of the THEMIS image reveals polygonal shapes on the floor of the channel system. Polygonal terrain on Mars is fairly common although the variety of forms and scales of the polygons suggests multiple modes of origin. Those in Ares Vallis resemble giant desiccation polygons that form in soils on Earth when a moist layer at depth drys out. While polygons can form in icy soils (permafrost) and even lava flows, their presence in a channel thought to have been carved by flowing water is at least consistent with a mode of origin that involved liquid water.Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.
2008-01-01
This image shows a small-scale polygonal pattern in the ground near NASA's Phoenix Mars Lander. This pattern is similar in appearance to polygonal structures in icy ground in the arctic regions of Earth. Phoenix touched down on the Red Planet at 4:53 p.m. Pacific Time (7:53 p.m. Eastern Time), May 25, 2008, in an arctic region called Vastitas Borealis, at 68 degrees north latitude, 234 degrees east longitude. This image was acquired by the Surface Stereo Imager shortly after landing. On the Phoenix mission calendar, landing day is known as Sol 0, the first Martian day of the mission. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.
2005-01-01
14 April 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a typical view of polygon-cracked and pitted surfaces unique to western Utopia Planitia. No other place on Mars has this appearance. Some Mars scientists have speculated that ground ice may be responsible for these landforms. Location near: 42.3oN, 275.6oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Summer
2003-01-01
MGS MOC Release No. MOC2-339, 23 April 2003This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a pattern of polygonal cracks and aligned, elliptical pits in western Utopia Planitia. The picture covers an area about 3 km (about 1.9 mi) wide near 44.9oN, 274.7oW. Sunlight illuminates the scene from the left.
Origin of giant Martian polygons
Mcgill, George E.; Hills, L. S.
1992-01-01
Extensive areas of the Martian northern plains in Utopia and Acidalia planitiae are characterized by 'polygonal terrane'. Polygonal terrane consists of material cut by complex troughs defining a pattern resembling mudcracks, columnar joints, or frost-wedge polygons on earth. However, the Martian polygons are orders of magnitude larger than these potential earth analogues, leading to severe mechanical difficulties for genetic models based on simple analogy arguments. Plate-bending and finite element models indicate that shrinkage of desiccating sediment or cooling volcanics accompanied by differential compaction over buried topography can account for the stresses responsible for polygon troughs as well as the large size of the polygons. Although trough widths and depths relate primarily to shrinkage, the large scale of the polygonl pattern relates to the spacing between topographic elevations on the surface buried beneath polygonal terrane material. Geological relationships favor a sedimentary origin for polygonal terrane material, but our model is not dependent on the specific genesis. Our analysis also suggests that the polygons must have formed at a geologically rapid rate.
2003-01-01
MGS MOC Release No. MOC2-428, 21 July 2003This June 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a polygonal pattern developed in seasonal carbon dioxide frost in the martian southern hemisphere. The frost accumulated during the recent southern winter; it is now spring, and the carbon dioxide frost is subliming away. This image is located near 80.4oS, 200.2oW; it is illuminated by sunlight from the upper left, and covers an area 3 km (1.9 mi) across.
Casimir effect in hyperbolic polygons
International Nuclear Information System (INIS)
Ahmedov, H
2007-01-01
Using the point splitting regularization method and the trace formula for the spectra of quantum-mechanical systems in hyperbolic polygons which are the fundamental domains of discrete isometry groups acting in the two-dimensional hyperboloid we calculate the Casimir energy for massless scalar fields in hyperbolic polygons. The dependence of the vacuum energy on the number of vertices is established
Metric inequalities for polygons
Directory of Open Access Journals (Sweden)
Adrian Dumitrescu
2013-07-01
Full Text Available Let A1,A2,…,An be the vertices of a polygon with unit perimeter, that is Σi |Ai Ai+1|=1. We derive various tight estimates on the minimum and maximum values of the sum of pairwise distances, and respectively sum of pairwise squared distances among its vertices. In most cases such estimates on these sums in the literature were known only for convex polygons.In the second part, we turn to a problem of Braß regarding the maximum perimeter of a simplen-gon (n odd contained in a disk of unit radius. The problem was recently solved by Audet et al. 2009, who gave an exact formula. Here we present an alternative simpler proof of this formula. We then examine what happens if the simplicity condition is dropped, and obtain an exact formula for the maximum perimeter in this case as well.
hZip2 and hZip3 zinc transporters are down regulated in human prostate adenocarcinomatous glands
Directory of Open Access Journals (Sweden)
Franklin Renty B
2007-06-01
Full Text Available Abstract Background The normal human prostate glandular epithelium has the unique function of accumulating high levels of zinc. In prostate cancer this capability is lost as an early event in the development of the malignant cells. The mechanism and factors responsible for the ability of the normal epithelial cells to accumulate zinc and the loss of this capability in the malignant cells need to be identified. We previously reported that Zip1 is an important zinc uptake transporter in prostate cells and is down regulated in the malignant cells in situ along with the depletion of zinc levels. In this report we investigated the expression of two other Zip family zinc transporters, Zip2 and Zip3 in malignant versus nonmalignant (normal and BPH glands. Zip2 and Zip3 relative protein levels were determined by immunohistochemistry analysis of human prostate tissue sections. Results Normal and BPH glandular epithelium consistently exhibited the strong presence of both Zip 2 and Zip3; whereas both transporters consistently were essentially non-detectable in the malignant glands. This represents the first report of the expression of Zip3 in human prostate tissue; and more importantly, reveals that ZiP2 and Zip3 are down regulated in malignant cells in situ as we also had demonstrated for Zip1. Zip2 and Zip3 transporter proteins were localized predominantly at the apical cell membrane, which is in contrast to the Zip1 localization at the basolateral membrane. Zip2 and Zip3 seemingly are associated with the re-uptake of zinc from prostatic fluid. Conclusion These results coupled with previous reports implicate Zip2 and Zip3 along with Zip1 as important zinc uptake transporters involved in the unique ability of prostate cells to accumulate high cellular zinc levels. Zip1 is important for the extraction of zinc from circulation as the primary source of cellular zinc. Zip 2 and Zip3 appear to be important for retention of the zinc in the cellular compartment
Aberdeen polygons: computer displays of physiological profiles for intensive care.
Green, C A; Logie, R H; Gilhooly, K J; Ross, D G; Ronald, A
1996-03-01
The clinician in an intensive therapy unit is presented regularly with a range of information about the current physiological state of the patients under care. This information typically comes from a variety of sources and in a variety of formats. A more integrated form of display incorporating several physiological parameters may be helpful therefore. Three experiments are reported that explored the potential use of analogue, polygon diagrams to display physiological data from patients undergoing intensive therapy. Experiment 1 demonstrated that information can be extracted readily from such diagrams comprising 8- or 10-sided polygons, but with an advantage for simpler polygons and for information displayed at the top of the diagram. Experiment 2 showed that colour coding removed these biases for simpler polygons and the top of the diagram, together with speeding the processing time. Experiment 3 used polygons displaying patterns of physiological data that were consistent with typical conditions observed in the intensive care unit. It was found that physicians can readily learn to recognize these patterns and to diagnose both the nature and severity of the patient's physiological state. These polygon diagrams appear to have some considerable potential for use in providing on-line summary information of a patient's physiological state.
2004-01-01
8 February 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a summertime scene in the south polar region of the red planet. A patch of bright frost--possibly water ice--is seen in the lower third of the image. Polygon patterns that have developed in the ice as it sublimes away can be seen; these are not evident in the defrosted surfaces, so they are thought to have formed in the frost. This image is located near 82.6oS, 352.5oW. Sunlight illuminates this scene from the upper left; the image covers an area 3 km (1.9 mi) wide.
Alabama ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, and freshwater fish species in Alabama. Vector polygons in this data set represent...
Maryland ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, anadromous, and freshwater fish species in Maryland. Vector polygons in this data...
Hawaii ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for reef, marine, estuarine, and native stream fish species in coastal Hawaii. Vector polygons in this data...
Hawaii ESI: INDEX (Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of the U.S. Geological Survey 1:24,000 topographic maps and other map and digital data boundaries...
Alabama ESI: REPTILES (Reptile Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for threatened/endangered and rare reptiles in Alabama. Vector polygons in this data set represent the rare...
Alabama ESI: INVERT (Invertebrate Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine and estuarine invertebrate species in Alabama. Vector polygons in this data set represent...
Virginia ESI: INVERT (Invertebrate Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, and rare invertebrate species in Virginia. Vector polygons in this data set...
Control Point Generated PLS - polygons
Minnesota Department of Natural Resources — The Control Point Generated PLS layer contains line and polygon features to the 1/4 of 1/4 PLS section (approximately 40 acres) and government lot level. The layer...
Virginia ESI: INDEX (Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
Louisiana ESI: BIRDS (Bird Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for waterfowl species and shorebirds in coastal Louisiana. Vector polygons in this data set represent...
Model for polygonal hydraulic jumps
DEFF Research Database (Denmark)
Martens, Erik Andreas; Watanabe, Shinya; Bohr, Tomas
2012-01-01
We propose a phenomenological model for the polygonal hydraulic jumps discovered by Ellegaard and co-workers [Nature (London) 392, 767 (1998); Nonlinearity 12, 1 (1999); Physica B 228, 1 (1996)], based on the known flow structure for the type-II hydraulic jumps with a "roller" (separation eddy...... nonhydrostatic pressure contributions from surface tension in light of recent observations by Bush and co-workers [J. Fluid Mech. 558, 33 (2006); Phys. Fluids 16, S4 (2004)]. The model can be analyzed by linearization around the circular state, resulting in a parameter relationship for nearly circular polygonal...... states. A truncated but fully nonlinear version of the model can be solved analytically. This simpler model gives rise to polygonal shapes that are very similar to those observed in experiments, even though surface tension is neglected, and the condition for the existence of a polygon with N corners...
Virginia ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, anadromous, and brackishwater fish species in Virginia. Vector polygons in this data...
Louisiana ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for freshwater (inland) fish species in coastal Louisiana. Vector polygons represent water-bodies and other...
Soils - Volusia County Soils (Polygons)
NSGIC Local Govt | GIS Inventory — Soils: 1:24000 SSURGO Map. Polygon boundaries of Soils in Volusia County, downloaded from SJRWMD and created by NRCS and SJRWMD. This data set is a digital version...
Atractividad local en la bifurcación de zip Local atractivity in zip bifurcation
Directory of Open Access Journals (Sweden)
Carlos Mario Escobar–Callejas
2010-12-01
Full Text Available En el presente trabajo se estudia la atractividad local del segmento de equilibriosque se forma en el fenómeno de la bifurcación de zip para un sistematridimensional de ecuaciones diferenciales no lineales. Este trabajo puede serconsiderado como una generalización de un resultado de Farkas en bifurcaciónde zip de modelos en competición.In this paper the local segment attractiveness equilibrium that forms on the phenomenon of zip bifurcation for a three–dimensional system of differential equations nonlinear is studied. This work may be regarded as a generalization as a result on Farkas’s zip bifurcation in competition models.
Error-Detecting Identification Codes for Algebra Students.
Sutherland, David C.
1990-01-01
Discusses common error-detecting identification codes using linear algebra terminology to provide an interesting application of algebra. Presents examples from the International Standard Book Number, the Universal Product Code, bank identification numbers, and the ZIP code bar code. (YP)
Inscribed polygons and Heron polynomials
International Nuclear Information System (INIS)
Varfolomeev, V V
2003-01-01
Heron's well-known formula expressing the area of a triangle in terms of the lengths of its sides is generalized in the following sense to polygons inscribed in a circle: it is proved that the area is an algebraic function of the lengths of the edges of the polygon. Similar results are proved for the diagonals and the radius of the circumscribed circle. The resulting algebraic equations are studied and elementary geometric applications of the algebraic results obtained are presented
Zernike-like systems in polygons and polygonal facets.
Ferreira, Chelo; López, José L; Navarro, Rafael; Sinusía, Ester Pérez
2015-07-20
Zernike polynomials are commonly used to represent the wavefront phase on circular optical apertures, since they form a complete and orthonormal basis on the unit disk. In [Opt. Lett.32, 74 (2007)10.1364/OL.32.000074OPLEDP0146-9592] we introduced a new Zernike basis for elliptic and annular optical apertures based on an appropriate diffeomorphism between the unit disk and the ellipse and the annulus. Here, we present a generalization of this Zernike basis for a variety of important optical apertures, paying special attention to polygons and the polygonal facets present in segmented mirror telescopes. On the contrary to ad hoc solutions, most of them based on the Gram-Smith orthonormalization method, here we consider a piecewise diffeomorphism that transforms the unit disk into the polygon under consideration. We use this mapping to define a Zernike-like orthonormal system over the polygon. We also consider ensembles of polygonal facets that are essential in the design of segmented mirror telescopes. This generalization, based on in-plane warping of the basis functions, provides a unique solution, and what is more important, it guarantees a reasonable level of invariance of the mathematical properties and the physical meaning of the initial basis functions. Both the general form and the explicit expressions for a typical example of telescope optical aperture are provided.
Tessellating the Sphere with Regular Polygons
Soto-Johnson, Hortensia; Bechthold, Dawn
2004-01-01
Tessellations in the Euclidean plane and regular polygons that tessellate the sphere are reviewed. The regular polygons that can possibly tesellate the sphere are spherical triangles, squares and pentagons.
Tensor Product of Polygonal Cell Complexes
Chien, Yu-Yen
2017-01-01
We introduce the tensor product of polygonal cell complexes, which interacts nicely with the tensor product of link graphs of complexes. We also develop the unique factorization property of polygonal cell complexes with respect to the tensor product, and study the symmetries of tensor products of polygonal cell complexes.
Approximation algorithms for guarding holey polygons ...
African Journals Online (AJOL)
Guarding edges of polygons is a version of art gallery problem.The goal is finding the minimum number of guards to cover the edges of a polygon. This problem is NP-hard, and to our knowledge there are approximation algorithms just for simple polygons. In this paper we present two approximation algorithms for guarding ...
Triangulating and guarding realistic polygons
Aloupis, G.; Bose, P.; Dujmovic, V.; Gray, C.M.; Langerman, S.; Speckmann, B.
2008-01-01
We propose a new model of realistic input: k-guardable objects. An object is k-guardable if its boundary can be seen by k guards in the interior of the object. In this abstract, we describe a simple algorithm for triangulating k-guardable polygons. Our algorithm, which is easily implementable, takes
Triangulating and guarding realistic polygons
Aloupis, G.; Bose, P.; Dujmovic, V.; Gray, C.M.; Langerman, S.; Speckmann, B.
2014-01-01
We propose a new model of realistic input: k-guardable objects. An object is k-guardable if its boundary can be seen by k guards. We show that k-guardable polygons generalize two previously identified classes of realistic input. Following this, we give two simple algorithms for triangulating
Brethour, Dylan; Mehrabian, Mohadeseh; Williams, Declan; Wang, Xinzhu; Ghodrati, Farinaz; Ehsani, Sepehr; Rubie, Elizabeth A; Woodgett, James R; Sevalle, Jean; Xi, Zhengrui; Rogaeva, Ekaterina; Schmitt-Ulms, Gerold
2017-01-18
The prion protein (PrP) evolved from the subbranch of ZIP metal ion transporters comprising ZIPs 5, 6 and 10, raising the prospect that the study of these ZIPs may reveal insights relevant for understanding the function of PrP. Building on data which suggested PrP and ZIP6 are critical during epithelial-to-mesenchymal transition (EMT), we investigated ZIP6 in an EMT paradigm using ZIP6 knockout cells, mass spectrometry and bioinformatic methods. Reminiscent of PrP, ZIP6 levels are five-fold upregulated during EMT and the protein forms a complex with NCAM1. ZIP6 also interacts with ZIP10 and the two ZIP transporters exhibit interdependency during their expression. ZIP6 contributes to the integration of NCAM1 in focal adhesion complexes but, unlike cells lacking PrP, ZIP6 deficiency does not abolish polysialylation of NCAM1. Instead, ZIP6 mediates phosphorylation of NCAM1 on a cluster of cytosolic acceptor sites. Substrate consensus motif features and in vitro phosphorylation data point toward GSK3 as the kinase responsible, and interface mapping experiments identified histidine-rich cytoplasmic loops within the ZIP6/ZIP10 heteromer as a novel scaffold for GSK3 binding. Our data suggests that PrP and ZIP6 inherited the ability to interact with NCAM1 from their common ZIP ancestors but have since diverged to control distinct posttranslational modifications of NCAM1.
Rotating Polygons on a Fluid Surface
DEFF Research Database (Denmark)
Bohr, Tomas; Jansson, Thomas; Haspang, Martin
spontaneously and the surface can take the shape of a rigidly rotating polygon. With water we have observed polygons with up to 6 corners. The rotation speed of the polygons does not coincide with that of the plate, but it is often mode-locked, such that the polygon rotates by one corner for each complete...... and R. Miraghaie, ”Symmetry breaking in free-surface cylinder flows”, J. Fluid Mech., 502, 99 (2004)). The polygons occur at much larger Reynolds numbers, for water around 500.000. Correspondingly, the dependence on viscosity is rather small....
Polygons, Stars, and Clusters; an Investigation of Polygon Displays
1988-01-01
variables were chosen, nine in each case , to give reasonably complex polygons without being too complex. I have seen no reported studies of the relation...Pont. Catalina C Datsun 210, Toyota Corolla, Dodge Colt, Honda Civic, Mazda GLC, Subaru, Ford Fiesta, Plym. Champ Figure 6. Clusters on the basis of...Merc. Marquis, Pont. Catalina, Pont. Grand Prix C Datsun 210, Toyota Corolla, Dodge Colt, Honda Civic, Mazda GLC, Subaru, Ford Fiesta, Plym. Champ
Leonhardt, Tereza; Sácký, Jan; Kotrba, Pavel
2018-04-01
A search of R. atropurpurea transcriptome for sequences encoding the transporters of the Zrt-, Irt-like Protein (ZIP) family, which are in eukaryotes integral to Zn supply into cytoplasm, allowed the identification of RaZIP1 cDNA with a predicted product belonging to ZIP I subfamily; it was subjected to functional studies in mutant Saccharomyces cerevisiae strains. The expression of RaZIP1, but not RaZIP1 H208A or RaZIP1 H232A mutants lacking conserved-among-ZIPs transmembrane histidyls, complemented Zn uptake deficiency in zrt1Δzrt2Δ yeasts. RaZIP1 substantially increased cellular Zn uptake in this strain and added to Zn sensitivity in zrc1Δcot1Δ mutant. The Fe uptake deficiency in ftr1Δ strain was not rescued and Mn uptake was insufficient for toxicity in Mn-sensitive pmr1Δ yeasts. By contrast, RaZIP1 increased Cd sensitivity in yap1Δ strain and conferred Cd transport activity in yeasts, albeit with substantially lower efficiency compared to Zn transport. In metal uptake assays, the accumulation of Zn in zrt1Δzrt2Δ strain remained unaffected by Cd, Fe, and Mn present in 20-fold molar excess over Zn. Immunofluorescence microscopy detected functional hemagglutinin-tagged HA::RaZIP1 on the yeast cell protoplast periphery. Altogether, these data indicate that RaZIP1 is a high-affinity plasma membrane transporter specialized in Zn uptake, and improve the understanding of the cellular and molecular biology of Zn in R. atropurpurea that is known for its ability to accumulate remarkably high concentrations of Zn.
Random walks and polygons in tight confinement
International Nuclear Information System (INIS)
Diao, Y; Ernst, C; Ziegler, U
2014-01-01
We discuss the effect of confinement on the topology and geometry of tightly confined random walks and polygons. Here the walks and polygons are confined in a sphere of radius R ≥ 1/2 and the polygons are equilateral with n edges of unit length. We illustrate numerically that for a fixed length of random polygons the knotting probability increases to one as the radius decreases to 1/2. We also demonstrate that for random polygons (walks) the curvature increases to πn (π(n – 1)) as the radius approaches 1/2 and that the torsion decreases to ≈ πn/3 (≈ π(n – 1)/3). In addition we show the effect of length and confinement on the average crossing number of a random polygon
Lucchitta, B. K.
1984-01-01
Polygonal-fracture patterns on the martian surface were discovered on Viking Orbiter images. The polygons are 2-20 km in diameter, much larger than those of known patterned ground on Earth. New observations show, however, that polygons exist on Mars that have diameters similar to those of ice-wedge polygons on Earth (generally a few meters to more than 100 m). Various explanations for the origin of these crustal features are examined; seasonal desiccation and thermal-contraction cracking in ice-rich ground. It is difficult to ascertain whether the polygons are forming today or are relics from the past. The crispness of some crack suggests a recent origin. On the other hand the absence of upturned edges (indicating actively forming ice wedges), the locally disintegrating ground, and a few possible superposed rayed craters indicate that the polygons are not forming at the present.
Parcels and Land Ownership - Volusia County Parcels (Polygons)
NSGIC Local Govt | GIS Inventory — Parcel Ownership Polygon Layer: Polygons showing property ownership created from the "master" subdivision base map for Volusia County. Multiple lots and parcels...
Entanglement complexity of semiflexible lattice polygons
International Nuclear Information System (INIS)
Orlandini, E; Tesi, M C; Whittington, S G
2005-01-01
We use Monte Carlo methods to study knotting in polygons on the simple cubic lattice with a stiffness fugacity. We investigate how the knot probability depends on stiffness and how the relative frequency of trefoils and figure eight knots changes as the stiffness changes. In addition, we examine the effect of stiffness on the writhe of the polygons. (letter to the editor)
Computing nonsimple polygons of minimum perimeter
Fekete, S.P.; Haas, A.; Hemmer, M.; Hoffmann, M.; Kostitsyna, I.; Krupke, D.; Maurer, F.; Mitchell, J.S.B.; Schmidt, A.; Schmidt, C.; Troegel, J.
2018-01-01
We consider the Minimum Perimeter Polygon Problem (MP3): for a given set V of points in the plane, find a polygon P with holes that has vertex set V , such that the total boundary length is smallest possible. The MP3 can be considered a natural geometric generalization of the Traveling Salesman
Kink-free deformations of polygons
Vegter, Gert
1989-01-01
We consider a discrete version of the Whitney-Graustein theorem concerning regular equivalence of closed curves. Two regular polygons P and P’, i.e. polygons without overlapping adjacent edges, are called regularly equivalent if there is a continuous one-parameter family Ps, 0 ≤ s ≤ 1, of regular
Accelerating Generalized Polygon Beams and Their Propagation
International Nuclear Information System (INIS)
Zhang Yun-Tian; Zhang Zhi-Gang; Cheng Teng; Zhang Qing-Chuan; Wu Xiao-Ping
2015-01-01
Accelerating beams with intensity cusps and exotic topological properties are drawing increasing attention as they have extensive uses in many intriguing fields. We investigate the structural features of accelerating polygon beams, show their generalized mathematical form theoretically, and discuss the even-numbered polygon beams. Furthermore, we also carry out the experiment and observe the intensity evolution during their propagation
Pan-Domain Analysis of ZIP Zinc Transporters
Directory of Open Access Journals (Sweden)
Laura E. Lehtovirta-Morley
2017-12-01
Full Text Available The ZIP (Zrt/Irt-like protein family of zinc transporters is found in all three domains of life. However, little is known about the phylogenetic relationship amongst ZIP transporters, their distribution, or their origin. Here we employed phylogenetic analysis to explore the evolution of ZIP transporters, with a focus on the major human fungal pathogen, Candida albicans. Pan-domain analysis of bacterial, archaeal, fungal, and human proteins revealed a complex relationship amongst the ZIP family members. Here we report (i a eukaryote-wide group of cellular zinc importers, (ii a fungal-specific group of zinc importers having genetic association with the fungal zincophore, and, (iii a pan-kingdom supercluster made up of two distinct subgroups with orthologues in bacterial, archaeal, and eukaryotic phyla.
Perceptually stable regions for arbitrary polygons.
Rocha, J
2003-01-01
Zou and Yan have recently developed a skeletonization algorithm of digital shapes based on a regularity/singularity analysis; they use the polygon whose vertices are the boundary pixels of the image to compute a constrained Delaunay triangulation (CDT) in order to find local symmetries and stable regions. Their method has produced good results but it is slow since its complexity depends on the number of contour pixels. This paper presents an extension of their technique to handle arbitrary polygons, not only polygons of short edges. Consequently, not only can we achieve results as good as theirs for digital images, but we can also compute skeletons of polygons of any number of edges. Since we can handle polygonal approximations of figures, the skeletons are more resilient to noise and faster to process.
Does a point lie inside a polygon
International Nuclear Information System (INIS)
Milgram, M.S.
1988-01-01
A superficially simple problem in computational geometry is that of determining whether a query point P lies in the interior of a polygon if it lies in the polygon's plane. Answering this question is often required when tracking particles in a Monte Carlo program; it is asked frequently and an efficient algorithm is crucial. Littlefield has recently rediscovered Shimrat's algorithm, while in separate works, Wooff, Preparata and Shamos and Mehlhorn, as well as Yamaguchi, give other algorithms. A practical algorithm answering this question when the polygon's plane is skewed in space is not immediately evident from most of these methods. Additionally, all but one fails when two sides extend to infinity (open polygons). In this paper the author review the above methods and present a new, efficient algorithm, valid for all convex polygons, open or closed, and topologically connected in n-dimensional space (n ≥ 2)
Hashimoto, Ayako; Ohkura, Katsuma; Takahashi, Masakazu; Kizu, Kumiko; Narita, Hiroshi; Enomoto, Shuichi; Miyamae, Yusaku; Masuda, Seiji; Nagao, Masaya; Irie, Kazuhiro; Ohigashi, Hajime; Andrews, Glen K; Kambe, Taiho
2015-12-01
Dietary zinc deficiency puts human health at risk, so we explored strategies for enhancing zinc absorption. In the small intestine, the zinc transporter ZIP4 functions as an essential component of zinc absorption. Overexpression of ZIP4 protein increases zinc uptake and thereby cellular zinc levels, suggesting that food components with the ability to increase ZIP4 could potentially enhance zinc absorption via the intestine. In the present study, we used mouse Hepa cells, which regulate mouse Zip4 (mZip4) in a manner indistinguishable from that in intestinal enterocytes, to screen for suitable food components that can increase the abundance of ZIP4. Using this ZIP4-targeting strategy, two such soybean extracts were identified that were specifically able to decrease mZip4 endocytosis in response to zinc. These soybean extracts also effectively increased the abundance of apically localized mZip4 in transfected polarized Caco2 and Madin-Darby canine kidney cells and, moreover, two apically localized mZip4 acrodermatitis enteropathica mutants. Soybean components were purified from one extract and soyasaponin Bb was identified as an active component that increased both mZip4 protein abundance and zinc levels in Hepa cells. Finally, we confirmed that soyasaponin Bb is capable of enhancing cell surface endogenous human ZIP4 in human cells. Our results suggest that ZIP4 targeting may represent a new strategy to improve zinc absorption in humans. © 2015 Authors; published by Portland Press Limited.
Stretched polygons in a lattice tube
Energy Technology Data Exchange (ETDEWEB)
Atapour, M [Department of Mathematics and Statistics, York University, Toronto, ON M3J 1P3 (Canada); Soteros, C E [Department of Mathematics and Statistics, University of Saskatchewan, Saskatoon, SK S7N 5E6 (Canada); Whittington, S G [Department of Chemistry, University of Toronto, Toronto, ON M5S 3H6 (Canada)], E-mail: atapour@mathstat.yorku.ca, E-mail: soteros@math.usask.ca, E-mail: swhittin@chem.utoronto.ca
2009-08-14
We examine the topological entanglements of polygons confined to a lattice tube and under the influence of an external tensile force f. The existence of the limiting free energy for these so-called stretched polygons is proved and then, using transfer matrix arguments, a pattern theorem for stretched polygons is proved. Note that the tube constraint allows us to prove a pattern theorem for any arbitrary value of f, while without the tube constraint it has so far only been proved for large values of f. The stretched polygon pattern theorem is used first to show that the average span per edge of a randomly chosen n-edge stretched polygon approaches a positive value, non-decreasing in f, as n {yields} {infinity}. We then show that the knotting probability of an n-edge stretched polygon confined to a tube goes to one exponentially as n {yields} {infinity}. Thus as n {yields} {infinity} when polygons are influenced by a force f, no matter its strength or direction, topological entanglements, as defined by knotting, occur with high probability. (fast track communication)
Stretched polygons in a lattice tube
International Nuclear Information System (INIS)
Atapour, M; Soteros, C E; Whittington, S G
2009-01-01
We examine the topological entanglements of polygons confined to a lattice tube and under the influence of an external tensile force f. The existence of the limiting free energy for these so-called stretched polygons is proved and then, using transfer matrix arguments, a pattern theorem for stretched polygons is proved. Note that the tube constraint allows us to prove a pattern theorem for any arbitrary value of f, while without the tube constraint it has so far only been proved for large values of f. The stretched polygon pattern theorem is used first to show that the average span per edge of a randomly chosen n-edge stretched polygon approaches a positive value, non-decreasing in f, as n → ∞. We then show that the knotting probability of an n-edge stretched polygon confined to a tube goes to one exponentially as n → ∞. Thus as n → ∞ when polygons are influenced by a force f, no matter its strength or direction, topological entanglements, as defined by knotting, occur with high probability. (fast track communication)
Direct Monte Carlo dose calculation using polygon-surface computational human model
International Nuclear Information System (INIS)
Jeong, Jong Hwi; Kim, Chan Hyeong; Yeom, Yeon Su; Cho, Sungkoo; Chung, Min Suk; Cho, Kun-Woo
2011-01-01
In the present study, a voxel-type computational human model was converted to a polygon-surface model, after which it was imported directly to the Geant4 code without using a voxelization process, that is, without converting back to a voxel model. The original voxel model was also imported to the Geant4 code, in order to compare the calculated dose values and the computational speed. The average polygon size of the polygon-surface model was ∼0.5 cm 2 , whereas the voxel resolution of the voxel model was 1.981 × 1.981 × 2.0854 mm 3 . The results showed a good agreement between the calculated dose values of the two models. The polygon-surface model was, however, slower than the voxel model by a factor of 6–9 for the photon energies and irradiation geometries considered in the present study, which nonetheless is considered acceptable, considering that direct use of the polygon-surface model does not require a separate voxelization process. (author)
Probing convex polygons with X-rays
International Nuclear Information System (INIS)
Edelsbrunner, H.; Skiena, S.S.
1988-01-01
An X-ray probe through a polygon measures the length of intersection between a line and the polygon. This paper considers the properties of various classes of X-ray probes, and shows how they interact to give finite strategies for completely describing convex n-gons. It is shown that (3n/2)+6 probes are sufficient to verify a specified n-gon, while for determining convex polygons (3n-1)/2 X-ray probes are necessary and 5n+O(1) sufficient, with 3n+O(1) sufficient given that a lower bound on the size of the smallest edge of P is known
Polygons on a rotating fluid surface
DEFF Research Database (Denmark)
Jansson, Thomas R.N.; Haspang, Martin P.; Jensen, Kåre H.
2006-01-01
We report a novel and spectacular instability of a fluid surface in a rotating system. In a flow driven by rotating the bottom plate of a partially filled, stationary cylindrical container, the shape of the free surface can spontaneously break the axial symmetry and assume the form of a polygon...... rotating rigidly with a speed different from that of the plate. With water, we have observed polygons with up to 6 corners. It has been known for many years that such flows are prone to symmetry breaking, but apparently the polygonal surface shapes have never been observed. The creation of rotating...
Federal Geographic Data Committee — The SMA implementation is comprised of one feature dataset, with several polygon feature classes, rather than a single feature class. SurfaceManagementAgency: The...
Zipping dielectric elastomer actuators: characterization, design and modeling
International Nuclear Information System (INIS)
Maffli, L; Rosset, S; Shea, H R
2013-01-01
We report on miniature dielectric elastomer actuators (DEAs) operating in zipping mode with an analytical model that predicts their behavior. Electrostatic zipping is a well-known mechanism in silicon MEMS to obtain large deformations and forces at lower voltages than for parallel plate electrostatic actuation. We extend this concept to DEAs, which allows us to obtain much larger out-of-plane displacements compared to silicon thanks to the softness of the elastomer membrane. We study experimentally the effect of sidewall angles and elastomer prestretch on 2.3 mm diameter actuators with PDMS membranes. With 15° and 22.5° sidewall angles, the devices zip in a bistable manner down 300 μm to the bottom of the chambers. The highly tunable bistable behavior is controllable by both chamber geometry and membrane parameters. Other specific characteristics of zipping DEAs include well-controlled deflected shape, tunable displacement versus voltage characteristics to virtually any shape, including multi-stable modes, sealing of embedded holes or channels for valving action and the reduction of the operating voltage. These properties make zipping DEAs an excellent candidate for applications such as integrated microfluidics actuators or Braille displays. (paper)
MEMS variable capacitance devices utilizing the substrate: II. Zipping varactors
Elshurafa, Amro M.
2010-03-22
This paper, the second and last in this series, introduces PolyMUMPS zipping varactors that exploit the substrate and provide a high tuning range and a high quality factor. Building on the important findings of part I of this paper, the substrate was utilized effectively once again in the design and fabrication of zipping varactors to attain devices with very good performance. Two zipping varactors are proposed, analysed theoretically, simulated, fabricated and tested successfully. The tuning range, quality factor and actuation voltage of those varactors are 4.5, 16.4, 55 V and 4.2, 17, 55 V respectively. Finally, and based on one of the proposed zipping varactors, a very large capacitance value varactor array, with a tuning range of 5.3, was designed and tested. To the best of our knowledge, these zipping varactors exhibit the best reported characteristics in PolyMUMPS to date within their category in terms of tuning range, quality factor, required actuation voltage and total area consumed. © 2010 IOP Publishing Ltd.
Columbia River ESI: INVERT (Invertebrate Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for clams, oysters, crabs, and other invertebrate species in Columbia River. Vector polygons in this data...
Louisiana ESI: REPTILES (Reptile and Amphibian Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for reptiles and amphibians in coastal Louisiana. Vector polygons represent reptile and amphibian habitats,...
Western Alaska ESI: BIOINDEX (Biological Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of the 1:250,000 map boundaries used in the creation of the Environmental Sensitivity Index (ESI)...
Comic image understanding based on polygon detection
Li, Luyuan; Wang, Yongtao; Tang, Zhi; Liu, Dong
2013-01-01
Comic image understanding aims to automatically decompose scanned comic page images into storyboards and then identify the reading order of them, which is the key technique to produce digital comic documents that are suitable for reading on mobile devices. In this paper, we propose a novel comic image understanding method based on polygon detection. First, we segment a comic page images into storyboards by finding the polygonal enclosing box of each storyboard. Then, each storyboard can be represented by a polygon, and the reading order of them is determined by analyzing the relative geometric relationship between each pair of polygons. The proposed method is tested on 2000 comic images from ten printed comic series, and the experimental results demonstrate that it works well on different types of comic images.
Western Alaska ESI: INDEX (Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all the hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
Columbia River ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, anadromous, and freshwater fish species in Columbia River. Vector polygons in this...
Infinite genus surfaces and irrational polygonal billiards
Valdez, Ferrán
2009-01-01
We prove that the natural invariant surface associated with the billiard game on an irrational polygonal table is homeomorphic to the Loch Ness monster, that is, the only orientable infinite genus topological real surface with exactly one end.
Western Alaska ESI: LAKES (Lake Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing lakes and land masses used in the creation of the Environmental Sensitivity Index (ESI) for Western Alaska. The...
Western Alaska ESI: HYDRO (Land Mass Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing coastal hydrography that defines the primary land masses used in the creation of the Environmental Sensitivity...
Southeast Alaska ESI: BIRDS (Bird Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains biological resource data for waterfowl in Southeast Alaska. Vector polygons in this data set represent locations of foraging and rafting...
Southeast Alaska ESI: MGT (Management Area Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains management area data for National Parks, Wildlife Refuges, and areas designated as Critical Habitat in Southeast Alaska. Vector polygons in...
Western Alaska ESI: MGT (Management Area Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains management area data for Designated Critical Habitats, Wildlife Refuges, Wild and Scenic Rivers, and State Parks. Vector polygons in this data...
From Newton's bucket to rotating polygons
DEFF Research Database (Denmark)
Bach, B.; Linnartz, E. C.; Vested, Malene Louise Hovgaard
2014-01-01
We present an experimental study of 'polygons' forming on the free surface of a swirling water flow in a partially filled cylindrical container. In our set-up, we rotate the bottom plate and the cylinder wall with separate motors. We thereby vary rotation rate and shear strength independently...... and move from a rigidly rotating 'Newton's bucket' flow to one where bottom and cylinder wall are rotating oppositely and the surface is strongly turbulent but flat on average. Between those two extremes, we find polygonal states for which the rotational symmetry is spontaneously broken. We investigate...... the phase diagram spanned by the two rotational frequencies at a given water filling height and find polygons in a regime, where the two frequencies are sufficiently different and, predominantly, when they have opposite signs. In addition to the extension of the family of polygons found with the stationary...
Hawaii ESI: REPTILES (Reptile and Amphibian Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for threatened/endangered sea turtles in coastal Hawaii. Vector polygons in this data set represent sea...
Virginia ESI: MGT (Management Area Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains boundaries for management areas, national parks, state and local parks, and wildlife refuges in Virginia. Vector polygons in this data set...
Western Alaska ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, and anadromous fish species in Western Alaska. Vector polygons in this data set...
Columbia River ESI: MGT (Management Area Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive human-use data for Wildlife Refuges, National Forests, and State Parks for the Columbia River area. Vector polygons in this data set...
Louisiana ESI: MGT (Management Area Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains boundaries for managed lands in coastal Louisiana. Vector polygons in this data set represent the management areas. Location-specific type and...
Louisiana ESI: PARISH (Parish Management Area Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains boundaries for parishes in coastal Louisiana. Vector polygons in this data set represent parish management areas. Location-specific type and...
Virginia ESI: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Virginia. The...
Southeast Alaska ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains biological resource data for estuarine, benthic, and pelagic fish in Southeast Alaska. Vector polygons in this data set represent locations of...
Anisotropic rectangular metric for polygonal surface remeshing
Pellenard, Bertrand
2013-06-18
We propose a new method for anisotropic polygonal surface remeshing. Our algorithm takes as input a surface triangle mesh. An anisotropic rectangular metric, defined at each triangle facet of the input mesh, is derived from both a user-specified normal-based tolerance error and the requirement to favor rectangle-shaped polygons. Our algorithm uses a greedy optimization procedure that adds, deletes and relocates generators so as to match two criteria related to partitioning and conformity.
Anisotropic rectangular metric for polygonal surface remeshing
Pellenard, Bertrand; Morvan, Jean-Marie; Alliez, Pierre
2013-01-01
We propose a new method for anisotropic polygonal surface remeshing. Our algorithm takes as input a surface triangle mesh. An anisotropic rectangular metric, defined at each triangle facet of the input mesh, is derived from both a user-specified normal-based tolerance error and the requirement to favor rectangle-shaped polygons. Our algorithm uses a greedy optimization procedure that adds, deletes and relocates generators so as to match two criteria related to partitioning and conformity.
Generating equilateral random polygons in confinement II
International Nuclear Information System (INIS)
Diao, Y; Ernst, C; Montemayor, A; Ziegler, U
2012-01-01
In this paper we continue an earlier study (Diao et al 2011 J. Phys. A: Math. Theor. 44 405202) on the generation algorithms of random equilateral polygons confined in a sphere. Here, the equilateral random polygons are rooted at the center of the confining sphere and the confining sphere behaves like an absorbing boundary. One way to generate such a random polygon is the accept/reject method in which an unconditioned equilateral random polygon rooted at origin is generated. The polygon is accepted if it is within the confining sphere, otherwise it is rejected and the process is repeated. The algorithm proposed in this paper offers an alternative to the accept/reject method, yielding a faster generation process when the confining sphere is small. In order to use this algorithm effectively, a large, reusable data set needs to be pre-computed only once. We derive the theoretical distribution of the given random polygon model and demonstrate, with strong numerical evidence, that our implementation of the algorithm follows this distribution. A run time analysis and a numerical error estimate are given at the end of the paper. (paper)
Control of grinding polygonal surfaces
Directory of Open Access Journals (Sweden)
Юрій Володимирович Петраков
2017-12-01
Full Text Available Grinding of non-round surfaces, in particular polygonal surfaces of dies, is characterized by substantial non stationary. At different sections of the profile, the change in the main characteristic (Material Removal Rate – MRR process reaches tens of times. To stabilize the grinding process, it is recommended to control the spindle speed of the workpiece CNC grinding machine. Created software that allows to design the control program on the basis of mathematical model of the system. The determination of MRR is realized automatically in the simulation of the grinding process which uses the algorithm developed for solving problems in geometric interaction of the workpiece and the wheel. In forming the control program is possible takes into account the limitations on the maximum circumferential force of cutting, and the maximum allowable acceleration of the machine spindle. Practice has shown that full stabilization is not obtained, even though the performance is increased more than 2 times, while ensuring the quality of the surface. The developed block diagram of the grinding process can serve as a basis for further improvement in the solution of dynamic problems.
Evens, Nicholas P; Buchner, Peter; Williams, Lorraine E; Hawkesford, Malcolm J
2017-10-01
Understanding the molecular basis of zinc (Zn) uptake and transport in staple cereal crops is critical for improving both Zn content and tolerance to low-Zn soils. This study demonstrates the importance of group F bZIP transcription factors and ZIP transporters in responses to Zn deficiency in wheat (Triticum aestivum). Seven group F TabZIP genes and 14 ZIPs with homeologs were identified in hexaploid wheat. Promoter analysis revealed the presence of Zn-deficiency-response elements (ZDREs) in a number of the ZIPs. Functional complementation of the zrt1/zrt2 yeast mutant by TaZIP3, -6, -7, -9 and -13 supported an ability to transport Zn. Group F TabZIPs contain the group-defining cysteine-histidine-rich motifs, which are the predicted binding site of Zn 2+ in the Zn-deficiency response. Conservation of these motifs varied between the TabZIPs suggesting that individual TabZIPs may have specific roles in the wheat Zn-homeostatic network. Increased expression in response to low Zn levels was observed for several of the wheat ZIPs and bZIPs; this varied temporally and spatially suggesting specific functions in the response mechanism. The ability of the group F TabZIPs to bind to specific ZDREs in the promoters of TaZIPs indicates a conserved mechanism in monocots and dicots in responding to Zn deficiency. In support of this, TabZIPF1-7DL and TabZIPF4-7AL afforded a strong level of rescue to the Arabidopsis hypersensitive bzip19 bzip23 double mutant under Zn deficiency. These results provide a greater understanding of Zn-homeostatic mechanisms in wheat, demonstrating an expanded repertoire of group F bZIP transcription factors, adding to the complexity of Zn homeostasis. © 2017 The Authors The Plant Journal published by John Wiley & Sons Ltd and Society for Experimental Biology.
Generating equilateral random polygons in confinement
International Nuclear Information System (INIS)
Diao, Y; Ernst, C; Montemayor, A; Ziegler, U
2011-01-01
One challenging problem in biology is to understand the mechanism of DNA packing in a confined volume such as a cell. It is known that confined circular DNA is often knotted and hence the topology of the extracted (and relaxed) circular DNA can be used as a probe of the DNA packing mechanism. However, in order to properly estimate the topological properties of the confined circular DNA structures using mathematical models, it is necessary to generate large ensembles of simulated closed chains (i.e. polygons) of equal edge lengths that are confined in a volume such as a sphere of certain fixed radius. Finding efficient algorithms that properly sample the space of such confined equilateral random polygons is a difficult problem. In this paper, we propose a method that generates confined equilateral random polygons based on their probability distribution. This method requires the creation of a large database initially. However, once the database has been created, a confined equilateral random polygon of length n can be generated in linear time in terms of n. The errors introduced by the method can be controlled and reduced by the refinement of the database. Furthermore, our numerical simulations indicate that these errors are unbiased and tend to cancel each other in a long polygon. (paper)
Minimal knotted polygons in cubic lattices
International Nuclear Information System (INIS)
Van Rensburg, E J Janse; Rechnitzer, A
2011-01-01
In this paper we examine numerically the properties of minimal length knotted lattice polygons in the simple cubic, face-centered cubic, and body-centered cubic lattices by sieving minimal length polygons from a data stream of a Monte Carlo algorithm, implemented as described in Aragão de Carvalho and Caracciolo (1983 Phys. Rev. B 27 1635), Aragão de Carvalho et al (1983 Nucl. Phys. B 215 209) and Berg and Foester (1981 Phys. Lett. B 106 323). The entropy, mean writhe, and mean curvature of minimal length polygons are computed (in some cases exactly). While the minimal length and mean curvature are found to be lattice dependent, the mean writhe is found to be only weakly dependent on the lattice type. Comparison of our results to numerical results for the writhe obtained elsewhere (see Janse van Rensburg et al 1999 Contributed to Ideal Knots (Series on Knots and Everything vol 19) ed Stasiak, Katritch and Kauffman (Singapore: World Scientific), Portillo et al 2011 J. Phys. A: Math. Theor. 44 275004) shows that the mean writhe is also insensitive to the length of a knotted polygon. Thus, while these results for the mean writhe and mean absolute writhe at minimal length are not universal, our results demonstrate that these values are quite close the those of long polygons regardless of the underlying lattice and length
MEMS variable capacitance devices utilizing the substrate: II. Zipping varactors
Elshurafa, Amro M.; El-Masry, Ezz I.
2010-01-01
and tested. To the best of our knowledge, these zipping varactors exhibit the best reported characteristics in PolyMUMPS to date within their category in terms of tuning range, quality factor, required actuation voltage and total area consumed. © 2010 IOP
Expression analysis of OsbZIP transcription factors in resistance ...
African Journals Online (AJOL)
zino
2013-08-21
Aug 21, 2013 ... Plant basic leucine zipper (bZIP) proteins play an essential role in the genes expression and regulation in higher plants. They have been shown to regulate diverse plant specific phenomena, including germination, floral induction and development, seed maturation, photomorphogenesis, biotic and.
Two generalizations of column-convex polygons
International Nuclear Information System (INIS)
Feretic, Svjetlan; Guttmann, Anthony J
2009-01-01
Column-convex polygons were first counted by area several decades ago, and the result was found to be a simple, rational, generating function. In this work we generalize that result. Let a p-column polyomino be a polyomino whose columns can have 1, 2, ..., p connected components. Then column-convex polygons are equivalent to 1-convex polyominoes. The area generating function of even the simplest generalization, namely 2-column polyominoes, is unlikely to be solvable. We therefore define two classes of polyominoes which interpolate between column-convex polygons and 2-column polyominoes. We derive the area generating functions of those two classes, using extensions of existing algorithms. The growth constants of both classes are greater than the growth constant of column-convex polyominoes. Rather tight lower bounds on the growth constants complement a comprehensive asymptotic analysis.
Steady state of tapped granular polygons
International Nuclear Information System (INIS)
Carlevaro, Carlos M; Pugnaloni, Luis A
2011-01-01
The steady state packing fraction of a tapped granular bed is studied for different grain shapes via a discrete element method. Grains are monosized regular polygons, from triangles to icosagons. Comparisons with disc packings show that the steady state packing fraction as a function of the tapping intensity presents the same general trends in polygon packings. However, better packing fractions are obtained, as expected, for shapes that can tessellate the plane (triangles, squares and hexagons). In addition, we find a sharp transition for packings of polygons with more than 13 vertices signaled by a discontinuity in the packing fraction at a particular tapping intensity. Density fluctuations for most shapes are consistent with recent experimental findings in disc packing; however, a peculiar behavior is found for triangles and squares
Polygons on a rotating fluid surface.
Jansson, Thomas R N; Haspang, Martin P; Jensen, Kåre H; Hersen, Pascal; Bohr, Tomas
2006-05-05
We report a novel and spectacular instability of a fluid surface in a rotating system. In a flow driven by rotating the bottom plate of a partially filled, stationary cylindrical container, the shape of the free surface can spontaneously break the axial symmetry and assume the form of a polygon rotating rigidly with a speed different from that of the plate. With water, we have observed polygons with up to 6 corners. It has been known for many years that such flows are prone to symmetry breaking, but apparently the polygonal surface shapes have never been observed. The creation of rotating internal waves in a similar setup was observed for much lower rotation rates, where the free surface remains essentially flat [J. M. Lopez, J. Fluid Mech. 502, 99 (2004). We speculate that the instability is caused by the strong azimuthal shear due to the stationary walls and that it is triggered by minute wobbling of the rotating plate.
Exact generating function for 2-convex polygons
International Nuclear Information System (INIS)
James, W R G; Jensen, I; Guttmann, A J
2008-01-01
Polygons are described as almost-convex if their perimeter differs from the perimeter of their minimum bounding rectangle by twice their 'concavity index', m. Such polygons are called m-convex polygons and are characterized by having up to m indentations in their perimeter. We first describe how we conjectured the (isotropic) generating function for the case m = 2 using a numerical procedure based on series expansions. We then proceed to prove this result for the more general case of the full anisotropic generating function, in which steps in the x and y directions are distinguished. In doing so, we develop tools that would allow for the case m > 2 to be studied
Generating equilateral random polygons in confinement III
International Nuclear Information System (INIS)
Diao, Y; Ernst, C; Montemayor, A; Ziegler, U
2012-01-01
In this paper we continue our earlier studies (Diao et al 2011 J. Phys. A: Math. Theor. 44 405202, Diao et al J. Phys. A: Math. Theor. 45 275203) on the generation methods of random equilateral polygons confined in a sphere. The first half of this paper is concerned with the generation of confined equilateral random walks. We show that if the selection of a vertex is uniform subject to the position of its previous vertex and the confining condition, then the distributions of the vertices are not uniform, although there exists a distribution such that if the initial vertex is selected following this distribution, then all vertices of the random walk follow this same distribution. Thus in order to generate a confined equilateral random walk, the selection of a vertex cannot be uniform subject to the position of its previous vertex and the confining condition. We provide a simple algorithm capable of generating confined equilateral random walks whose vertex distribution is almost uniform in the confinement sphere. In the second half of this paper we show that any process generating confined equilateral random walks can be turned into a process generating confined equilateral random polygons with the property that the vertex distribution of the polygons approaches the vertex distribution of the walks as the polygons get longer and longer. In our earlier studies, the starting point of the confined polygon is fixed at the center of the sphere. The new approach here allows us to move the starting point of the confined polygon off the center of the sphere. (paper)
Equipartitioning and balancing points of polygons
Directory of Open Access Journals (Sweden)
Shunmugam Pillay
2010-07-01
Full Text Available The centre of mass G of a triangle has the property that the rays to the vertices from G sweep out triangles having equal areas. We show that such points, termed equipartitioning points in this paper, need not exist in other polygons. A necessary and sufficient condition for a quadrilateral to have an equipartitioning point is that one of its diagonals bisects the other. The general theorem, namely, necessary and sufficient conditions for equipartitioning points for arbitrary polygons to exist, is also stated and proved. When this happens, they are in general, distinct from the centre of mass. In parallelograms, and only in them, do the two points coincide.
Slow relaxation in weakly open rational polygons.
Kokshenev, Valery B; Vicentini, Eduardo
2003-07-01
The interplay between the regular (piecewise-linear) and irregular (vertex-angle) boundary effects in nonintegrable rational polygonal billiards (of m equal sides) is discussed. Decay dynamics in polygons (of perimeter P(m) and small opening Delta) is analyzed through the late-time survival probability S(m) approximately equal t(-delta). Two distinct slow relaxation channels are established. The primary universal channel exhibits relaxation of regular sliding orbits, with delta=1. The secondary channel is given by delta>1 and becomes open when m>P(m)/Delta. It originates from vertex order-disorder dual effects and is due to relaxation of chaoticlike excitations.
Random packing of regular polygons and star polygons on a flat two-dimensional surface.
Cieśla, Michał; Barbasz, Jakub
2014-08-01
Random packing of unoriented regular polygons and star polygons on a two-dimensional flat continuous surface is studied numerically using random sequential adsorption algorithm. Obtained results are analyzed to determine the saturated random packing ratio as well as its density autocorrelation function. Additionally, the kinetics of packing growth and available surface function are measured. In general, stars give lower packing ratios than polygons, but when the number of vertexes is large enough, both shapes approach disks and, therefore, properties of their packing reproduce already known results for disks.
Pan, Yanglu; Hu, Xin; Li, Chunyan; Xu, Xing; Su, Chenggang; Li, Jinhua; Song, Hongyuan; Zhang, Xingguo; Pan, Yu
2017-01-01
The basic leucine zipper (bZIP) transcription factors have crucial roles in plant stress responses. In this study, the bZIP family gene SlbZIP38 (GenBank accession No: XM004239373) was isolated from a tomato (Solanum lycopersicum cv. Ailsa Craig) mature leaf cDNA library. The DNA sequence of SlbZIP38 encodes a protein of 484 amino acids, including a highly conserved bZIP DNA-binding domain in the C-terminal region. We found that SlbZIP38 was differentially expressed in various organs of the tomato plant and was downregulated by drought, salt stress, and abscisic acid (ABA). However, overexpression of SlbZIP38 significantly decreased drought and salt stress tolerance in tomatoes (Ailsa Craig). The findings that SlbZIP38 overexpression reduced the chlorophyll and free proline content in leaves but increased the malondialdehyde content may explain the reduced drought and salt tolerance observed in these lines. These results suggest that SlbZIP38 is a negative regulator of drought and salt resistance that acts by modulating ABA signaling. PMID:29261143
Dilation-optimal edge deletion in polygonal cycles
Ahn, H.K.; Farshi, M.; Knauer, C.; Smid, M.H.M.; Wang, Y.; Tokuyama, T.
2007-01-01
Let C be a polygonal cycle on n vertices in the plane. A randomized algorithm is presented which computes in O(n log3 n) expected time, the edge of C whose removal results in a polygonal path of smallest possible dilation. It is also shown that the edge whose removal gives a polygonal path of
Calculating the Areas of Polygons with a Smartphone Light Sensor
Kapucu, Serkan; Simsek, Mertkan; Öçal, Mehmet Fatih
2017-01-01
This study explores finding the areas of polygons with a smartphone light sensor. A square and an irregular pentagon were chosen as our polygons. During the activity, the LED light was placed at the vertices of our polygons, and the illuminance values of this LED light were detected by the smartphone light sensor. The smartphone was placed on a…
Automatically repairing invalid polygons with a constrained triangulation
Ledoux, H.; Arroyo Ohori, K.; Meijers, M.
2012-01-01
Although the validation of single polygons has received considerable attention, the automatic repair of invalid polygons has not. Automated repair methods can be considered as interpreting ambiguous or ill-defined polygons and giving a coherent and clearly defined output. At this moment, automatic
Directory of Open Access Journals (Sweden)
Yu Zhang
2018-03-01
Full Text Available Tanshinones are a class of bioactive components in the traditional Chinese medicine Salvia miltiorrhiza, and their biosynthesis and regulation have been widely studied. Current studies show that basic leucine zipper (bZIP proteins regulate plant secondary metabolism, growth and developmental processes. However, the bZIP transcription factors involved in tanshinone biosynthesis are unknown. Here, we conducted the first genome-wide survey of the bZIP gene family and analyzed the phylogeny, gene structure, additional conserved motifs and alternative splicing events in S. miltiorrhiza. A total of 70 SmbZIP transcription factors were identified and categorized into 11 subgroups based on their phylogenetic relationships with those in Arabidopsis. Moreover, seventeen SmbZIP genes underwent alternative splicing events. According to the transcriptomic data, the SmbZIP genes that were highly expressed in the Danshen root and periderm were selected. Based on the prediction of bZIP binding sites in the promoters and the co-expression analysis and co-induction patterns in response to Ag+ treatment via quantitative real-time polymerase chain reaction (qRT-PCR, we concluded that SmbZIP7 and SmbZIP20 potentially participate in the regulation of tanshinone biosynthesis. These results provide a foundation for further functional characterization of the candidate SmbZIP genes, which have the potential to increase tanshinone production. KEY WORDS: bZIP genes, Salvia miltiorrhiza, Phylogenetic analysis, Expression pattern analysis, Tanshinone biosynthesis
Realistic roofs over a rectilinear polygon
Ahn, Heekap; Bae, Sangwon; Knauer, Christian; Lee, Mira; Shin, Chansu; Vigneron, Antoine E.
2013-01-01
Given a simple rectilinear polygon P in the xy-plane, a roof over P is a terrain over P whose faces are supported by planes through edges of P that make a dihedral angle π/4 with the xy-plane. According to this definition, some roofs may have faces
Exploring Nonconvex, Crossed and Degenerate Polygons
Contreras, Jose N.
2004-01-01
An exploration of nonconvex, crossed, and degenerate polygons (NCCDPs) are described with the help of examples with pedagogical tips and recommendations that are found useful when teaching the mathematical process of extending geometric patterns to NCCDPs. The study concludes that investigating such extensions with interactive geometry software…
Generating realistic roofs over a rectilinear polygon
Ahn, Heekap; Bae, Sangwon; Knauer, Christian; Lee, Mira; Shin, Chansu; Vigneron, Antoine E.
2011-01-01
Given a simple rectilinear polygon P in the xy-plane, a roof over P is a terrain over P whose faces are supported by planes through edges of P that make a dihedral angle π/4 with the xy-plane. In this paper, we introduce realistic roofs by imposing
The structure of near polygons with quads
Brouwer, A.E.; Wilbrink, H.A.
1983-01-01
We develop a structure theory for near polygons with quads. Main results are the existence of sub 2j-gons for 2jd and the nonexistence of regular sporadic 2d-gons for d4 with s>1 and t 2>1 and t 3t 2(t 2+1).
Fair partitions of polygons: An elementary introduction
Indian Academy of Sciences (India)
In this paper we discuss only convex polygonal regions with finite number of sides. But we think this property holds ... trivial interest and have updated [9] into the present paper. 2. Proof of the conjecture N = .... surface have a proper intersection if they cut through each other either at a point or after being coincident in a finite ...
Ji, Xiaoyu; Liu, Guifeng; Liu, Yujia; Zheng, Lei; Nie, Xianguang; Wang, Yucheng
2013-10-04
Tamarix spp. are woody halophyte, which are very tolerant to abiotic stresses such as salinity and drought, but little is known about their specific stress response systems. Basic leucine zipper proteins (bZIPs) play important roles in the ability of plants to withstand adverse environmental conditions. However, their exact roles in abiotic stress tolerance are still not fully known. In the current study, we functionally characterized a bZIP gene (ThbZIP1) from Tamarix hispida in response to abiotic stresses. We addressed the regulatory network of ThbZIP1 in three levels, i.e. its upstream regulators, the cis-acting elements recognized by ThbZIP1, and its downstream target genes. Two MYCs were found to bind to E-box, in the promoter of ThbZIP1 to activate its expression. Expression of ThbZIP1 is induced by ABA, salt, drought, methyl viologen and cold. ThbZIP1 can specifically bind to ACGT elements, with the highest binding affinity to the C-box, followed by the G-box and lastly the A-box. Compared with wild-type (Col-0) Arabidopsis, transgenic plants expressing ThbZIP1 had an increased tolerance to drought and salt, but had an increased sensitivity to ABA during seed germination and root growth; meanwhile, ROS level, cell death and water loss rate in transgenic plants were significantly reduced. Microarray analyses showed that many ROS scavenging genes were up-regulated by ThbZIP1 under salt stress conditions. Based on these data, we suggest that ThbZIP1 confers abiotic stress tolerance through activating stress tolerance genes to modulate ROS scavenging ability and other physiological changes involved in stress tolerance, and plays an important role in the ABA-mediated stress response of T. hispida.
A model of competing species that exhibits zip bifurcation
Directory of Open Access Journals (Sweden)
Luis F. Echeverri
2017-01-01
Full Text Available El objetivo de este trabajo es presentar un modelo concreto d e poblaciones de especies en competición que exhibe la bifurc ación Zip. La bifurcación zip fue introducida por Farkas en 1984 para un si stema tridi- mensional de ecuaciones diferenciales ordinarias que desc ribe un quimiostato. Estudiaremos un sistema tridimensional de ecuaciones dife renciales ordinarias que modela la competición de dos poblaciones distintas de pr edadores por una única población presa. El sistema usa funciones trigonomét ricas concretas pa- ra representar la tasa de crecimiento de la presa y la respues ta funcional del predador. El modelo exhibe diferentes clases de comportami entos y muestra ejemplos de los llamados principio de exclusión competitiva y la competición de un r-estratega contra un k-estratega . Adicionalmente, para ilustrar la bi- furcacion zip, presentaremos algunas simulaciones numéri cas.
A polygon soup representation for free viewpoint video
Colleu, T.; Pateux, S.; Morin, L.; Labit, C.
2010-02-01
This paper presents a polygon soup representation for multiview data. Starting from a sequence of multi-view video plus depth (MVD) data, the proposed representation takes into account, in a unified manner, different issues such as compactness, compression, and intermediate view synthesis. The representation is built in two steps. First, a set of 3D quads is extracted using a quadtree decomposition of the depth maps. Second, a selective elimination of the quads is performed in order to reduce inter-view redundancies and thus provide a compact representation. Moreover, the proposed methodology for extracting the representation allows to reduce ghosting artifacts. Finally, an adapted compression technique is proposed that limits coding artifacts. The results presented on two real sequences show that the proposed representation provides a good trade-off between rendering quality and data compactness.
Some solvable, and as yet unsolvable, polygon and walk models
International Nuclear Information System (INIS)
Guttmann, Anthony J
2006-01-01
One partly solvable and two solvable models of polygons are discussed. Using a simple transfer matrix approach Iwan Jensen has derived very long series expansions for the perimeter generating function of both three-choice polygons and punctured staircase polygons. In both cases it is found that all the terms in the generating function can be reproduced from a linear Fuchsian differential equation of order 8. We report on an analysis of the properties of the differential equations. Recently Enrica Duchi has discussed the problem of so-called prudent self-avoiding walks. We discuss the polygon analogue of this problem, and argue that the generating function for prudent polygons is unlikely to be differentiably finite, though a restricted version of the problem, called prudent polygons of the second type, is likely to be differentiably finite. The exact generating function for prudent polygons of the first type is also found
Directory of Open Access Journals (Sweden)
Lina Zhang
2017-05-01
Full Text Available The group C-bZIP transcription factors (TFs are involved in diverse biological processes, such as the regulation of seed storage protein (SSP production and the responses to pathogen challenge and abiotic stress. However, our knowledge of the abiotic functions of group C-bZIP genes in wheat remains limited. Here, we present the function of a novel TabZIP14-B gene in wheat. This gene belongs to the group C-bZIP TFs and contains six exons and five introns; three haplotypes were identified among accessions of tetraploid and hexaploid wheat. A subcellular localization analysis indicated that TabZIP14-B was targeted to the nucleus of tobacco epidermal cells. A transactivation assay demonstrated that TabZIP14-B showed transcriptional activation ability and was capable of binding the abscisic acid (ABA responsive element (ABRE in yeast. RT-qPCR revealed that TabZIP14-B was expressed in the roots, stems, leaves, and young spikes and was up-regulated by exogenous ABA, salt, low-temperature, and polyethylene glycol (PEG stress treatments. Furthermore, Arabidopsis plants overexpressing TabZIP14-B exhibited enhanced tolerance to salt, freezing stresses and ABA sensitivity. Overexpression of TabZIP14-B resulted in increased expression of the AtRD29A, AtCOR47, AtRD20, AtGSTF6, and AtRAB18 genes and changes in several physiological characteristics. These results suggest that TabZIP14-B could function as a positive regulator in mediating the abiotic stress response.
Self-assembly of chiral molecular polygons.
Jiang, Hua; Lin, Wenbin
2003-07-09
Treatment of 2,2'-diacetyl-1,1'-binaphthyl-6,6'-bis(ethyne), L-H2, with 1 equiv of trans-Pt(PEt3)2Cl2 led to a mixture of different sizes of chiral metallocycles [trans-(PEt3)2Pt(L)]n (n = 3-8, 1-6). Each of the chiral molecular polygons 1-6 was purified by silica gel column chromatography and characterized by 1H, 13C{1H}, and 31P{1H} NMR spectroscopy, MS, IR, UV-vis, and circular dichroism spectroscopies, and microanalysis. The presence of tunable cavities (1.4-4.3 nm) and chiral functionalities in these molecular polygons promises to make them excellent receptors for a variety of guests.
Simulating 3D deformation using connected polygons
Tarigan, J. T.; Jaya, I.; Hardi, S. M.; Zamzami, E. M.
2018-03-01
In modern 3D application, interaction between user and the virtual world is one of an important factor to increase the realism. This interaction can be visualized in many forms; one of them is object deformation. There are many ways to simulate object deformation in virtual 3D world; each comes with different level of realism and performance. Our objective is to present a new method to simulate object deformation by using a graph-connected polygon. In this solution, each object contains multiple level of polygons in different level of volume. The proposed solution focusses on performance rather while maintaining the acceptable level of realism. In this paper, we present the design and implementation of our solution and show that this solution is usable in performance sensitive 3D application such as games and virtual reality.
Counting convex polygons in planar point sets
Mitchell, J.S.B.; Rote, G.; Sundaram, Gopalakrishnan; Woeginger, G.J.
1995-01-01
Given a set S of n points in the plane, we compute in time O(n3) the total number of convex polygons whose vertices are a subset of S. We give an O(m · n3) algorithm for computing the number of convex k-gons with vertices in S, for all values k = 3,…, m; previously known bounds were exponential
Non-convex polygons clustering algorithm
Directory of Open Access Journals (Sweden)
Kruglikov Alexey
2016-01-01
Full Text Available A clustering algorithm is proposed, to be used as a preliminary step in motion planning. It is tightly coupled to the applied problem statement, i.e. uses parameters meaningful only with respect to it. Use of geometrical properties for polygons clustering allows for a better calculation time as opposed to general-purpose algorithms. A special form of map optimized for quick motion planning is constructed as a result.
137Cs in Research Polygon 'Sumbar'
International Nuclear Information System (INIS)
Skoko, B.; Marovic, G.; Babic, D.; Vickovic, I.
2011-01-01
In 2009, Radiation Protection Unit of the Institute for Medical Reseach and Occupational Health started a radioactivity measurement programme in research polygon ''Sumbar''. The purpose of these investigations is to collect as many data as possible about the contamination of the polygon that is mainly covered by a forest of English oak (Quercus robur) and hornbeam (Carpinus betulus). Once contaminated, forests represent long-term sources of radiation exposure to specific population groups which are using them as a source of foodstuffs. After the Chernobyl accident, researchers have shown that there has been more variability in radionuclide activity concentration in forests than in agricultural ecosystems. In order to carry out a radioactivity screening of the polygon, we randomly chosed three sampling sites for collecting soil, grass and moss samples. Different species of mushrooms were collected over the whole polygon area. The average activity concentration of 137Cs in soil for two sampling sites is (123 @ 9) Bq kg -1 , while the result for the third site is lower by an order of magnitude ((16.1@0.5) Bq kg -1 ). The activity concentration of 137Cs in grass samples ranges from (0.43 @ 0.03) Bq kg -1 to (13.2 @ 0.1) Bq kg -1 , and in moss samples from (8.7 @ 0.2) Bq kg -1 to (57.8 @ 0.3) Bq kg - 1. In five collected mushroom species, the activity of 137Cs is in the range between (4.1 @ 0.5) Bq kg -1 and (610 @ 5) Bq kg -1 , the lowest and the highest values referreing to Clitocybe nebularis and Gymnopus dryophilus, respectively. Parasitic mushrooms exhibit activity below the minimum detection level. Our preliminary results show and confirm variability of the activity concentration of 137Cs in different parts of this ecosystem. (author)
Functional Analysis of Maize Silk-Specific ZmbZIP25 Promoter
Directory of Open Access Journals (Sweden)
Wanying Li
2018-03-01
Full Text Available ZmbZIP25 (Zea mays bZIP (basic leucine zipper transcription factor 25 is a function-unknown protein that belongs to the D group of the bZIP transcription factor family. RNA-seq data showed that the expression of ZmbZIP25 was tissue-specific in maize silks, and this specificity was confirmed by RT-PCR (reverse transcription-polymerase chain reaction. In situ RNA hybridization showed that ZmbZIP25 was expressed exclusively in the xylem of maize silks. A 5′ RACE (rapid amplification of cDNA ends assay identified an adenine residue as the transcription start site of the ZmbZIP25 gene. To characterize this silk-specific promoter, we isolated and analyzed a 2450 bp (from −2083 to +367 and a 2600 bp sequence of ZmbZIP25 (from −2083 to +517, the transcription start site was denoted +1. Stable expression assays in Arabidopsis showed that the expression of the reporter gene GUS driven by the 2450 bp ZmbZIP25 5′-flanking fragment occurred exclusively in the papillae of Arabidopsis stigmas. Furthermore, transient expression assays in maize indicated that GUS and GFP expression driven by the 2450 bp ZmbZIP25 5′-flanking sequences occurred only in maize silks and not in other tissues. However, no GUS or GFP expression was driven by the 2600 bp ZmbZIP25 5′-flanking sequences in either stable or transient expression assays. A series of deletion analyses of the 2450 bp ZmbZIP25 5′-flanking sequence was performed in transgenic Arabidopsis plants, and probable elements prediction analysis revealed the possible presence of negative regulatory elements within the 161 bp region from −1117 to −957 that were responsible for the specificity of the ZmbZIP25 5′-flanking sequence.
Conversion of ICRP male reference phantom to polygon-surface phantom
Yeom, Yeon Soo; Han, Min Cheol; Kim, Chan Hyeong; Jeong, Jong Hwi
2013-10-01
The International Commission on Radiological Protection (ICRP) reference phantoms, developed based on computed tomography images of human bodies, provide much more realism of human anatomy than the previously used MIRD5 (Medical Internal Radiation Dose) mathematical phantoms. It has been, however, realized that the ICRP reference phantoms have some critical limitations showing a considerable amount of holes for the skin and wall organs mainly due to the nature of voxels of which the phantoms are made, especially due to their low voxel resolutions. To address this problem, we are planning to develop the polygon-surface version of ICRP reference phantoms by directly converting the ICRP reference phantoms (voxel phantoms) to polygon-surface phantoms. The objective of this preliminary study is to see if it is indeed possible to construct the high-quality polygon-surface phantoms based on the ICRP reference phantoms maintaining identical organ morphology and also to identify any potential issues, and technologies to address these issues, in advance. For this purpose, in the present study, the ICRP reference male phantom was roughly converted to a polygon-surface phantom. Then, the constructed phantom was implemented in Geant4, Monte Carlo particle transport code, for dose calculations, and the calculated dose values were compared with those of the original ICRP reference phantom to see how much the calculated dose values are sensitive to the accuracy of the conversion process. The results of the present study show that it is certainly possible to convert the ICRP reference phantoms to surface phantoms with enough accuracy. In spite of using relatively less resources (original ICRP reference phantoms, it is believed that the polygon-surface version of ICRP reference phantoms properly developed will not only provide the same or similar dose values (say, difference <5 or 10%) for highly penetrating radiations, but also provide correct dose values for the weakly penetrating
DEFF Research Database (Denmark)
Castro, Pedro Humberto Araújo R F; Lilay, Grmay Hailu; Muñoz-Mérida, Antonio
2017-01-01
Basic leucine zipper (bZIP) transcription factors control important developmental and physiological processes in plants. In Arabidopsis thaliana, the three gene F-bZIP subfamily has been associated with zinc deficiency and salt stress response. Benefiting from the present abundance of plant genomic...... data, we performed an evolutionary and structural characterization of plant F-bZIPs. We observed divergence during seed plant evolution, into two groups and inferred different selective pressures for each. Group 1 contains AtbZIP19 and AtbZIP23 and appears more conserved, whereas Group 2, containing...... of AtZIP4. A survey of AtZIP4 orthologs promoters across different plant taxa revealed an enrichment of the Zinc Deficiency Response Element (ZDRE) to which both AtbZIP19/23 bind. Overall, our results indicate that while the AtbZIP24 function in the regulation of the salt stress response may...
Novel mechanism of aberrant ZIP4 expression with zinc supplementation in oral tumorigenesis
International Nuclear Information System (INIS)
Ishida, Sho; Kasamatsu, Atsushi; Endo-Sakamoto, Yosuke; Nakashima, Dai; Koide, Nao; Takahara, Toshikazu; Shimizu, Toshihiro; Iyoda, Manabu; Shiiba, Masashi; Tanzawa, Hideki; Uzawa, Katsuhiro
2017-01-01
Zrt-Irt-like protein 4 (ZIP4) is critical molecule for proper mammalian development and releasing zinc from vesicular compartments. Recent studies suggested that ZIP4 plays an important role of tumor progression in pancreatic, prostate, and hepatocellular cancers, however, little is known about the detail mechanism of ZIP4 in their cancers. In the present study, we examined the possibility of ZIP4 as a new molecular target for oral squamous cell carcinoma (OSCC). We evaluated ZIP4 expression in OSCC-derived cell lines and primary OSCC samples by quantitative RT-PCR, immunoblotting, and immunohistochemistry (IHC). We also analyzed the clinical correlation between ZIP4 status and clinical behaviors in patients with OSCC. In addition, ZIP4 knockdown cells (shZIP4 cells) and ZnCl 2 treatment were used for functional experiments, including cellular proliferation assay, zinc uptake assay, and cell-cycle analysis. ZIP4 mRNA and protein were up-regulated significantly in OSCCs compared with normal counterparts in vitro and in vivo. IHC showed that ZIP4 expression in the primary OSCC was positively correlated with primary tumoral size. The shZIP4 cells showed decrease accumulation of intercellular zinc and decreased cellular growth by cell-cycle arrest at the G1 phase, resulting from up-regulation of cyclin-dependent kinase inhibitors and down-regulation of cyclins and cyclin-dependent kinases. Since cellular growth of OSCC cells after treatment with zinc was significantly greater than control cells, we speculated that intercellular ZnCl 2 accumulation is an important factor for cellular growth. Consistent with our hypothesis, not only decreased zinc uptake by ZIP4 knockdown but also chelating agent, N,N,N′,N′-tetrakis(2-pyridylmethyl) ethylenediamine (TPEN), showed inhibitory effects of cellular proliferation. Therefore, our data provide evidence for an essential role of ZIP4 and intracellular zinc for tumoral growth in OSCC, suggesting that zinc uptake might be a
Structure and function of homodomain-leucine zipper (HD-Zip) proteins.
Elhiti, Mohamed; Stasolla, Claudio
2009-02-01
Homeodomain-leucine zipper (HD-Zip) proteins are transcription factors unique to plants and are encoded by more than 25 genes in Arabidopsis thaliana. Based on sequence analyses these proteins have been classified into four distinct groups: HD-Zip I-IV. HD-Zip proteins are characterized by the presence of two functional domains; a homeodomain (HD) responsible for DNA binding and a leucine zipper domain (Zip) located immediately C-terminal to the homeodomain and involved in protein-protein interaction. Despite sequence similarities HD-ZIP proteins participate in a variety of processes during plant growth and development. HD-Zip I proteins are generally involved in responses related to abiotic stress, abscisic acid (ABA), blue light, de-etiolation and embryogenesis. HD-Zip II proteins participate in light response, shade avoidance and auxin signalling. Members of the third group (HD-Zip III) control embryogenesis, leaf polarity, lateral organ initiation and meristem function. HD-Zip IV proteins play significant roles during anthocyanin accumulation, differentiation of epidermal cells, trichome formation and root development.
Stress sensing in plants by the ER stress sensor/transducer, bZIP28
Directory of Open Access Journals (Sweden)
Renu eSrivastava
2014-02-01
Full Text Available Two classes of ER stress sensors are known in plants, membrane associated bZIP transcription factors and RNA splicing factors. ER stress occurs under adverse environmental conditions and results from the accumulation of misfolded or unfolded proteins in the ER lumen. One of the membrane-associated transcription factors activated by heat and ER stress agents is bZIP28. In its inactive form, bZIP28 is a type II protein with a single pass transmembrane domain, residing in the ER. bZIP28’s N-terminus, containing a transcriptional activation domain, is oriented towards the cytoplasm and its C-terminal tail is inserted into the ER lumen. In response to stress, bZIP28 exits the ER and moves to the Golgi where it is proteolytically processed, liberating its cytosolic component which relocates to the nucleus to upregulate stress-response genes. bZIP28 is thought to sense stress through its interaction with the major ER chaperone, BIP. BiP binds to bZIP28’s lumenal domain under unstressed conditions and retains it in the ER. BIP binds to the intrinsically disordered regions on bZIP28’s lumen-facing tail. A truncated form of bZIP28, without its C-terminal tail is not retained in the ER but migrates constitutively to the nucleus. Upon stress, BiP releases bZIP28 allowing it to exit the ER. One model to account for the release of bZIP28 by BiP is that BiP is competed away from bZIP28 by the accumulation of misfolded proteins in the ER. However, other forces such as changes in energy charge levels, redox conditions or interaction with DNAJ proteins may also promote release of bZIP28 from BiP. Movement of bZIP28 from the ER to the Golgi is assisted by the interaction of elements of the COPII machinery with the cytoplasmic domain of bZIP28. Thus, the mobilization of bZIP28 in response to stress involves the dissociation of factors that retain it in the ER and the association of factors that mediate its further organelle-to-organelle movement.
Generating random walks and polygons with stiffness in confinement
International Nuclear Information System (INIS)
Diao, Y; Ernst, C; Saarinen, S; Ziegler, U
2015-01-01
The purpose of this paper is to explore ways to generate random walks and polygons in confinement with a bias toward stiffness. Here the stiffness refers to the curvature angle between two consecutive edges along the random walk or polygon. The stiffer the walk (polygon), the smaller this angle on average. Thus random walks and polygons with an elevated stiffness have lower than expected curvatures. The authors introduced and studied several generation algorithms with a stiffness parameter s>0 that regulates the expected curvature angle at a given vertex in which the random walks and polygons are generated one edge at a time using conditional probability density functions. Our generating algorithms also allow the generation of unconfined random walks and polygons with any desired mean curvature angle. In the case of random walks and polygons confined in a sphere of fixed radius, we observe that, as expected, stiff random walks or polygons are more likely to be close to the confinement boundary. The methods developed here require that the random walks and random polygons be rooted at the center of the confinement sphere. (paper)
The magnetic field generated by a rotating charged polygon
International Nuclear Information System (INIS)
Wan, Songlin; Chen, Xiangyu; Teng, Baohua; Fu, Hao; Li, Yefeng; Wu, Minghe; Wu, Shaoyi; Balfour, E A
2014-01-01
The magnetic field along the symmetry axis of a regular polygon carrying a uniform electric charge on its edges is calculated systematically when the polygon is rotated about this axis of symmetry. A group of circular current-carrying coils arranged concentrically about the axis of the polygon has been designed to simulate the magnetic field characteristics of the rotating charged polygon. The magnetic field of the simulated coils is measured using the PASCO magnetic field sensor. The results show that the theoretical calculation agrees well with the experimental results. (paper)
Decryption-decompression of AES protected ZIP files on GPUs
Duong, Tan Nhat; Pham, Phong Hong; Nguyen, Duc Huu; Nguyen, Thuy Thanh; Le, Hung Duc
2011-10-01
AES is a strong encryption system, so decryption-decompression of AES encrypted ZIP files requires very large computing power and techniques of reducing the password space. This makes implementations of techniques on common computing system not practical. In [1], we reduced the original very large password search space to a much smaller one which surely containing the correct password. Based on reduced set of passwords, in this paper, we parallel decryption, decompression and plain text recognition for encrypted ZIP files by using CUDA computing technology on graphics cards GeForce GTX295 of NVIDIA, to find out the correct password. The experimental results have shown that the speed of decrypting, decompressing, recognizing plain text and finding out the original password increases about from 45 to 180 times (depends on the number of GPUs) compared to sequential execution on the Intel Core 2 Quad Q8400 2.66 GHz. These results have demonstrated the potential applicability of GPUs in this cryptanalysis field.
International Nuclear Information System (INIS)
Exner, P.; Kolerov, G.I.
1981-01-01
Properties of the subset of polygonal paths in the Hilbert space H of paths referring to a d-dimensional quantum-mechanical system are examined. Using the reproduction kernel technique we prove that each element of H is approximated by polygonal paths uniformly with respect to the ''norm'' of time-interval partitions. This result will be applied in the second part of the present paper to prove consistency of the uniform polygonal-path extension of the Feynman maps [ru
Reprogramming of metabolism by the Arabidopsis thaliana bZIP11 transcription factor
Ma, J.
2012-01-01
The Arabidopsis bZIP11 transcription factor is known to regulate amino acid metabolism, and transcriptomic analysis suggests that bZIP11 has a broader regulatory effects in metabolism. Moreover, sucrose controls its translation via its uORF and all the available evidences point to the fact that
ZIP13: A Study of Drosophila Offers an Alternative Explanation for the Corresponding Human Disease
Directory of Open Access Journals (Sweden)
Guiran Xiao
2018-01-01
Full Text Available The fruit fly Drosophila melanogaster has become an important model organism to investigate metal homeostasis and human diseases. Previously we identified dZIP13 (CG7816, a member of the ZIP transporter family (SLC39A and presumably a zinc importer, is in fact physiologically primarily responsible to move iron from the cytosol into the secretory compartments in the fly. This review will discuss the implication of this finding for the etiology of Spondylocheirodysplasia-Ehlers-Danlos Syndrome (SCD–EDS, a human disease defective in ZIP13. We propose an entirely different model in that lack of iron in the secretory compartment may underlie SCD-EDS. Altogether three different working models are discussed, supported by relevant findings made in different studies, with uncertainties, and questions remained to be solved. We speculate that the distinct ZIP13 sequence features, different from those of all other ZIP family members, may confer it special transport properties.
Finding the Maximal Area of Bounded Polygons in a Circle
Rokach, Arie
2005-01-01
The article deals with the area of polygons that are inscribed in a given circle. Naturally, the following question arises: Among all n-polygons that are inscribed in a given circle, which one has the biggest area? Intuitively, it may be guessed that is suitable for secondary students, and without any use id calculus, but only using very…
Beam envelope profile of non-centrosymmetric polygonal phase space
International Nuclear Information System (INIS)
Chen Yinbao; Xie Xi
1984-01-01
The general theory of beam envelope profile of non-centrosymmetric polygonal phase space is developed. By means of this theory the beam envelope profile of non-centrosymmetric polygonal phase space can be calculated directly. An example is carried out in detail to show the practical application of the theory
The regulatory network of ThbZIP1 in response to abscisic acid treatment
Directory of Open Access Journals (Sweden)
Xiaoyu eJi
2015-02-01
Full Text Available Previously, a bZIP transcription factor from Tamarix hispida, ThbZIP1, was characterized: plants overexpressing ThbZIP1 displayed improved salt stress tolerance but were sensitive to abscisic acid (ABA. In the current study, we further characterized the regulatory network of ThbZIP1 and the mechanism of ABA sensitivity mediated by ThbZIP1. An ABF transcription factor from T. hispida, ThABF1, directly regulates the expression of ThbZIP1. Microarray analysis identified 1,662 and 1,609 genes that were respectively significantly upregulated or downregulated by ThbZIP1 when exposed to ABA. GO analysis showed that the processes including response to stimulus, catalytic activity, binding function, and metabolic process were highly altered in ThbZIP1 expressing plants exposed to ABA. The gene expression in ThbZIP1 transformed plants were compared between exposed to ABA and salt on the genome scale. Genes differentially regulated by both salt and ABA treatment only accounted for 9.75% of total differentially regulated genes. GO analysis showed that structural molecule activity, organelle part, membrane-enclosed lumen, reproduction and reproductive process are enhanced by ABA but inhibited by salt stress. Conversely, immune system and multi-organism process were improved by salt but inhibited by ABA. Transcription regulator activity, enzyme regulator activity and developmental process were significantly altered by ABA but were not affected by salt stress. Our study provides insights into how ThbZIP1 mediates ABA and salt stress response at the molecular level.
Hamiltonian evolutions of twisted polygons in RPn
International Nuclear Information System (INIS)
Beffa, Gloria Marì; Wang, Jing Ping
2013-01-01
In this paper we find a discrete moving frame and their associated invariants along projective polygons in RP n , and we use them to describe invariant evolutions of projective N-gons. We then apply a reduction process to obtain a natural Hamiltonian structure on the space of projective invariants for polygons, establishing a close relationship between the projective N-gon invariant evolutions and the Hamiltonian evolutions on the invariants of the flow. We prove that any Hamiltonian evolution is induced on invariants by an invariant evolution of N-gons—what we call a projective realization—and both evolutions are connected explicitly in a very simple way. Finally, we provide a completely integrable evolution (the Boussinesq lattice related to the lattice W 3 -algebra), its projective realization in RP 2 and its Hamiltonian pencil. We generalize both structures to n-dimensions and we prove that they are Poisson, defining explicitly the n-dimensional generalization of the planar evolution (a discretization of the W n -algebra). We prove that the generalization is completely integrable, and we also give its projective realization, which turns out to be very simple. (paper)
Linking of uniform random polygons in confined spaces
Arsuaga, J.; Blackstone, T.; Diao, Y.; Karadayi, E.; Saito, M.
2007-03-01
In this paper, we study the topological entanglement of uniform random polygons in a confined space. We derive the formula for the mean squared linking number of such polygons. For a fixed simple closed curve in the confined space, we rigorously show that the linking probability between this curve and a uniform random polygon of n vertices is at least 1-O\\big(\\frac{1}{\\sqrt{n}}\\big) . Our numerical study also indicates that the linking probability between two uniform random polygons (in a confined space), of m and n vertices respectively, is bounded below by 1-O\\big(\\frac{1}{\\sqrt{mn}}\\big) . In particular, the linking probability between two uniform random polygons, both of n vertices, is bounded below by 1-O\\big(\\frac{1}{n}\\big) .
Linking of uniform random polygons in confined spaces
International Nuclear Information System (INIS)
Arsuaga, J; Blackstone, T; Diao, Y; Karadayi, E; Saito, M
2007-01-01
In this paper, we study the topological entanglement of uniform random polygons in a confined space. We derive the formula for the mean squared linking number of such polygons. For a fixed simple closed curve in the confined space, we rigorously show that the linking probability between this curve and a uniform random polygon of n vertices is at least 1-O(1/√n). Our numerical study also indicates that the linking probability between two uniform random polygons (in a confined space), of m and n vertices respectively, is bounded below by 1-O(1/√(mn)). In particular, the linking probability between two uniform random polygons, both of n vertices, is bounded below by 1-O(1/n)
International Nuclear Information System (INIS)
Tajima, Hiromi; Iwata, Yuji; Iwano, Megumi; Takayama, Seiji; Koizumi, Nozomu
2008-01-01
Among 75 bZIP transcription factors identified in Arabidopsis, 3 (AtbZIP17, AtbZIP28, and AtbZIP49) possess a putative transmembrane domain (TMD) in addition to AtbZIP60, which was characterized previously. In the present study, cDNAs of AtbZIP17 and AtbZIP28 were isolated. Truncated forms of AtbZIP17 and AtbZIP28 lacking the C-terminal domain including TMD were examined as putative active forms. One of them, AtbZIP28ΔC, activated BiP1 and BiP3 promoters through the cis-elements P-UPRE and ERSE responsible for the ER stress response. Subsequently, a fusion protein of green fluorescent protein (GFP) and AtbZIP28 was expressed in Arabidopsis cultured cells. Under non-stress conditions, GFP fluorescence localization almost overlapped with an ER marker; however, tunicamycin and dithiothreitol treatment clearly increased GFP fluorescence in the nucleus suggesting that the N-terminal fragment of AtbZIP28 translocates to the nucleus in response to ER stress
A polygonal nodal SP3 method for whole core Pin-by-Pin neutronics calculation
Energy Technology Data Exchange (ETDEWEB)
Li, Yunzhao; Wu, Hongchun; Cao, Liangzhi, E-mail: xjtulyz@gmail.com, E-mail: hongchun@mail.xjtu.edu.cn, E-mail: caolz@mail.xjtu.edu.cn [School of Nuclear Science and Technology, Xi' an Jiaotong University, Shaanxi (China)
2011-07-01
In this polygonal nodal-SP3 method, neutron transport equation is transformed by employing an isotropic SP3 method into two coupled equations that are both in the same mathematic form with the diffusion equation, and then a polygonal nodal method is proposed to solve the two coupled equations. In the polygonal nodal method, adjacent nodes are coupled through partial currents, and a nodal response matrix between incoming and outgoing currents is obtained by expanding detailed nodal flux distribution into a sum of exponential functions. This method avoids the transverse integral technique, which is widely used in regular nodal method and can not be used in triangular geometry because of the mathematical singularity. It is demonstrated by the numerical results of the test problems that the k{sub eff} and power distribution agree well with other codes, the triangular nodal-SP3 method appears faster, and that whole core pin-by-pin transport calculation with fine meshes is feasible after parallelization and acceleration. (author)
Wenrich, M. L.; Christensen, P. R.
1993-01-01
The mechanism for the genesis of the polygonal terrains in Acidalia and Utopia Planitia has long been sought: however, no completely satisfying model was put forth that characterizes the evolution of these complexly patterned terrains. The polygons are roughly hexagonal but some are not entirely enclosed by fractures. These polygonal features range in widths from approximately 5 to 20 km. Several origins were proposed that describe the polygon borders as desiccation cracks, columnar jointing in a cooled lava, or frost-wedge features. These tension-induced cracking hypotheses were addressed by Pechmann, who convincingly disputes these mechanisms of formation based on scale magnitude difficulties and morphology. Pechmann suggests instead that the cracks delineating the 5-20-km-wide polygons on the northern plains of Mars are graben resulting from deep-seated, uniform, horizontal tension. The difficulty with this hypothesis is that no analogous polygonal forms are known to have originated by tectonism on Earth. McGill and Hills propose that the polygonal terrains on Mars resulted from either rapid desiccation of sediments or cooling of volcanics coupled with differential compaction of the material over a buried irregular topographic surface. They suggest that fracturing was enhanced over the areas of positive relief and was suppressed above the topographic lows. McGill and Hills suggest that the spacing of the topographic highs primarily controls the size of the Martian polygons and the physics of the shrinkage process is a secondary concern. Ray et. al. conducted a terrestrial study of patterned ground in periglacial areas of the U.S. to determine the process responsible for polygonal ground formation. They developed a model for polygon formation in which convection of seasonal melt water above a permafrost layer, driven by an unstable density stratification, differentially melts the permafrost interface, causing it to become undulatory.
Uehara, Erica; Deguchi, Tetsuo
2017-12-07
We show that the average size of self-avoiding polygons (SAPs) with a fixed knot is much larger than that of no topological constraint if the excluded volume is small and the number of segments is large. We call it topological swelling. We argue an "enhancement" of the scaling exponent for random polygons with a fixed knot. We study them systematically through SAP consisting of hard cylindrical segments with various different values of the radius of segments. Here we mean by the average size the mean-square radius of gyration. Furthermore, we show numerically that the topological balance length of a composite knot is given by the sum of those of all constituent prime knots. Here we define the topological balance length of a knot by such a number of segments that topological entropic repulsions are balanced with the knot complexity in the average size. The additivity suggests the local knot picture.
Alagarasan, Ganesh; Dubey, Mahima; Aswathy, Kumar S; Chandel, Girish
2017-01-01
Genes in the ZIP family encode transcripts to store and transport bivalent metal micronutrient, particularly iron (Fe) and or zinc (Zn). These transcripts are important for a variety of functions involved in the developmental and physiological processes in many plant species, including most, if not all, Poaceae plant species and the model species Arabidopsis. Here, we present the report of a genome wide investigation of orthologous ZIP genes in Setaria italica and the identification of 7 single copy genes. RT-PCR shows 4 of them could be used to increase the bio-availability of zinc and iron content in grains. Of 36 ZIP members, 25 genes have traces of signal peptide based sub-cellular localization, as compared to those of plant species studied previously, yet translocation of ions remains unclear. In silico analysis of gene structure and protein nature suggests that these two were preeminent in shaping the functional diversity of the ZIP gene family in S. italica . NAC, bZIP and bHLH are the predominant Fe and Zn responsive transcription factors present in SiZIP genes. Together, our results provide new insights into the signal peptide based/independent iron and zinc translocation in the plant system and allowed identification of ZIP genes that may be involved in the zinc and iron absorption from the soil, and thus transporting it to the cereal grain underlying high micronutrient accumulation.
Directory of Open Access Journals (Sweden)
Ganesh Alagarasan
2017-05-01
Full Text Available Genes in the ZIP family encode transcripts to store and transport bivalent metal micronutrient, particularly iron (Fe and or zinc (Zn. These transcripts are important for a variety of functions involved in the developmental and physiological processes in many plant species, including most, if not all, Poaceae plant species and the model species Arabidopsis. Here, we present the report of a genome wide investigation of orthologous ZIP genes in Setaria italica and the identification of 7 single copy genes. RT-PCR shows 4 of them could be used to increase the bio-availability of zinc and iron content in grains. Of 36 ZIP members, 25 genes have traces of signal peptide based sub-cellular localization, as compared to those of plant species studied previously, yet translocation of ions remains unclear. In silico analysis of gene structure and protein nature suggests that these two were preeminent in shaping the functional diversity of the ZIP gene family in S. italica. NAC, bZIP and bHLH are the predominant Fe and Zn responsive transcription factors present in SiZIP genes. Together, our results provide new insights into the signal peptide based/independent iron and zinc translocation in the plant system and allowed identification of ZIP genes that may be involved in the zinc and iron absorption from the soil, and thus transporting it to the cereal grain underlying high micronutrient accumulation.
Visual feature discrimination versus compression ratio for polygonal shape descriptors
Heuer, Joerg; Sanahuja, Francesc; Kaup, Andre
2000-10-01
In the last decade several methods for low level indexing of visual features appeared. Most often these were evaluated with respect to their discrimination power using measures like precision and recall. Accordingly, the targeted application was indexing of visual data within databases. During the standardization process of MPEG-7 the view on indexing of visual data changed, taking also communication aspects into account where coding efficiency is important. Even if the descriptors used for indexing are small compared to the size of images, it is recognized that there can be several descriptors linked to an image, characterizing different features and regions. Beside the importance of a small memory footprint for the transmission of the descriptor and the memory footprint in a database, eventually the search and filtering can be sped up by reducing the dimensionality of the descriptor if the metric of the matching can be adjusted. Based on a polygon shape descriptor presented for MPEG-7 this paper compares the discrimination power versus memory consumption of the descriptor. Different methods based on quantization are presented and their effect on the retrieval performance are measured. Finally an optimized computation of the descriptor is presented.
Hepatic ZIP14-mediated zinc transport is required for adaptation to endoplasmic reticulum stress.
Kim, Min-Hyun; Aydemir, Tolunay B; Kim, Jinhee; Cousins, Robert J
2017-07-18
Extensive endoplasmic reticulum (ER) stress damages the liver, causing apoptosis and steatosis despite the activation of the unfolded protein response (UPR). Restriction of zinc from cells can induce ER stress, indicating that zinc is essential to maintain normal ER function. However, a role for zinc during hepatic ER stress is largely unknown despite important roles in metabolic disorders, including obesity and nonalcoholic liver disease. We have explored a role for the metal transporter ZIP14 during pharmacologically and high-fat diet-induced ER stress using Zip14 -/- (KO) mice, which exhibit impaired hepatic zinc uptake. Here, we report that ZIP14-mediated hepatic zinc uptake is critical for adaptation to ER stress, preventing sustained apoptosis and steatosis. Impaired hepatic zinc uptake in Zip14 KO mice during ER stress coincides with greater expression of proapoptotic proteins. ER stress-induced Zip14 KO mice show greater levels of hepatic steatosis due to higher expression of genes involved in de novo fatty acid synthesis, which are suppressed in ER stress-induced WT mice. During ER stress, the UPR-activated transcription factors ATF4 and ATF6α transcriptionally up-regulate Zip14 expression. We propose ZIP14 mediates zinc transport into hepatocytes to inhibit protein-tyrosine phosphatase 1B (PTP1B) activity, which acts to suppress apoptosis and steatosis associated with hepatic ER stress. Zip14 KO mice showed greater hepatic PTP1B activity during ER stress. These results show the importance of zinc trafficking and functional ZIP14 transporter activity for adaptation to ER stress associated with chronic metabolic disorders.
Generating realistic roofs over a rectilinear polygon
Ahn, Heekap
2011-01-01
Given a simple rectilinear polygon P in the xy-plane, a roof over P is a terrain over P whose faces are supported by planes through edges of P that make a dihedral angle π/4 with the xy-plane. In this paper, we introduce realistic roofs by imposing a few additional constraints. We investigate the geometric and combinatorial properties of realistic roofs, and show a connection with the straight skeleton of P. We show that the maximum possible number of distinct realistic roofs over P is ( ⌊(n-4)/4⌋ (n-4)/2) when P has n vertices. We present an algorithm that enumerates a combinatorial representation of each such roof in O(1) time per roof without repetition, after O(n 4) preprocessing time. We also present an O(n 5)-time algorithm for computing a realistic roof with minimum height or volume. © 2011 Springer-Verlag.
Rotational Fourier tracking of diffusing polygons.
Mayoral, Kenny; Kennair, Terry P; Zhu, Xiaoming; Milazzo, James; Ngo, Kathy; Fryd, Michael M; Mason, Thomas G
2011-11-01
We use optical microscopy to measure the rotational Brownian motion of polygonal platelets that are dispersed in a liquid and confined by depletion attractions near a wall. The depletion attraction inhibits out-of-plane translational and rotational Brownian fluctuations, thereby facilitating in-plane imaging and video analysis. By taking fast Fourier transforms (FFTs) of the images and analyzing the angular position of rays in the FFTs, we determine an isolated particle's rotational trajectory, independent of its position. The measured in-plane rotational diffusion coefficients are significantly smaller than estimates for the bulk; this difference is likely due to the close proximity of the particles to the wall arising from the depletion attraction.
High speed printing with polygon scan heads
Stutz, Glenn
2016-03-01
To reduce and in many cases eliminate the costs associated with high volume printing of consumer and industrial products, this paper investigates and validates the use of the new generation of high speed pulse on demand (POD) lasers in concert with high speed (HS) polygon scan heads (PSH). Associated costs include consumables such as printing ink and nozzles, provisioning labor, maintenance and repair expense as well as reduction of printing lines due to high through put. Targets that are applicable and investigated include direct printing on plastics, printing on paper/cardboard as well as printing on labels. Market segments would include consumer products (CPG), medical and pharmaceutical products, universal ID (UID), and industrial products. In regards to the POD lasers employed, the wavelengths include UV(355nm), Green (532nm) and IR (1064nm) operating within the repetition range of 180 to 250 KHz.
Self-avoiding polygons and walks in slits
International Nuclear Information System (INIS)
Alvarez, J; Whittington, S G; Rensburg, E J Janse van; Soteros, C E
2008-01-01
A polymer in a confined geometry may be modeled by a self-avoiding walk or a self-avoiding polygon confined between two parallel walls. In two dimensions, this model involves self-avoiding walks or self-avoiding polygons in the square lattice between two parallel confining lines. Interactions of the polymer with the confining walls are introduced by energy terms associated with edges in the walk or polygon which are at or near the confining lines. We use transfer-matrix methods to investigate the forces between the walk or polygon and the confining lines, as well as to investigate the effects of the confining slit's width and of the energy terms on the thermodynamic properties of the walks or polygons in several models. The phase diagram found for the self-avoiding walk models is qualitatively similar to the phase diagram of a directed walk model confined between two parallel lines, as was previously conjectured. However, the phase diagram of one of our polygon models is found to be significantly different and we present numerical data to support this. For that particular model we prove that, for any finite values of the energy terms, there are an infinite number of slit widths where a polygon will induce a steric repulsion between the confining lines
Cai, Wangting; Yang, Yaling; Wang, Weiwei; Guo, Guangyan; Liu, Wei; Bi, Caili
2018-03-01
The basic leucine zipper (bZIP) proteins play important roles against abiotic stress in plants, including cold stress. However, most bZIPs involved in plant freezing tolerance are positive regulators. Only a few bZIPs function negatively in cold stress response. In this study, TabZIP6, a Group C bZIP transcription factor gene from common wheat (Triticum aestivum L.), was cloned and characterized. The transcript of TabZIP6 was strongly induced by cold treatment (4 °C). TabZIP6 is a nuclear-localized protein with transcriptional activation activity. Arabidopsis plants overexpressing TabZIP6 showed decreased tolerance to freezing stress. Microarray as well as quantitative real-time PCR (qRT-PCR) analysis showed that CBFs and some key COR genes, including COR47 and COR15B, were down-regulated by cold treatment in TabZIP6-overexpressing Arabidopsis lines. TabZIP6 was capable of binding to the G-box motif and the CBF1 and CBF3 promoters in yeast cells. A yeast two-hybrid assay revealed that TabZIP6, as well as the other two Group S bZIP proteins involved in cold stress tolerance in wheat, Wlip19 and TaOBF1, can form homodimers by themselves and heterodimers with each other. These results suggest that TabZIP6 may function negatively in the cold stress response by binding to the promoters of CBFs, and thereby decreasing the expression of downstream COR genes in TabZIP6-overexpressing Arabidopsis seedlings. Copyright © 2018. Published by Elsevier Masson SAS.
Chopperla, Ramakrishna; Singh, Sonam; Mohanty, Sasmita; Reddy, Nanja; Padaria, Jasdeep C; Solanke, Amolkumar U
2017-10-01
Basic leucine zipper (bZIP) transcription factors comprise one of the largest gene families in plants. They play a key role in almost every aspect of plant growth and development and also in biotic and abiotic stress tolerance. In this study, we report isolation and characterization of EcbZIP17 , a group B bZIP transcription factor from a climate smart cereal, finger millet ( Eleusine coracana L.). The genomic sequence of EcbZIP17 is 2662 bp long encompassing two exons and one intron with ORF of 1722 bp and peptide length of 573 aa. This gene is homologous to AtbZIP17 ( Arabidopsis ), ZmbZIP17 (maize) and OsbZIP60 (rice) which play a key role in endoplasmic reticulum (ER) stress pathway. In silico analysis confirmed the presence of basic leucine zipper (bZIP) and transmembrane (TM) domains in the EcbZIP17 protein. Allele mining of this gene in 16 different genotypes by Sanger sequencing revealed no variation in nucleotide sequence, including the 618 bp long intron. Expression analysis of EcbZIP17 under heat stress exhibited similar pattern of expression in all the genotypes across time intervals with highest upregulation after 4 h. The present study established the conserved nature of EcbZIP17 at nucleotide and expression level.
Conformal array design on arbitrary polygon surface with transformation optics
Energy Technology Data Exchange (ETDEWEB)
Deng, Li, E-mail: dengl@bupt.edu.cn; Hong, Weijun, E-mail: hongwj@bupt.edu.cn; Zhu, Jianfeng; Peng, Biao; Li, Shufang [Beijing Key Laboratory of Network System Architecture and Convergence, School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, 100876 Beijing (China); Wu, Yongle, E-mail: wuyongle138@gmail.com [Beijing Key Laboratory of Work Safety Intelligent Monitoring, School of Electronic Engineering, Beijing University of Posts and Telecommunications, 100876 Beijing (China)
2016-06-15
A transformation-optics based method to design a conformal antenna array on an arbitrary polygon surface is proposed and demonstrated in this paper. This conformal antenna array can be adjusted to behave equivalently as a uniformly spaced linear array by applying an appropriate transformation medium. An typical example of general arbitrary polygon conformal arrays, not limited to circular array, is presented, verifying the proposed approach. In summary, the novel arbitrary polygon surface conformal array can be utilized in array synthesis and beam-forming, maintaining all benefits of linear array.
Interpolation Error Estimates for Mean Value Coordinates over Convex Polygons.
Rand, Alexander; Gillette, Andrew; Bajaj, Chandrajit
2013-08-01
In a similar fashion to estimates shown for Harmonic, Wachspress, and Sibson coordinates in [Gillette et al., AiCM, to appear], we prove interpolation error estimates for the mean value coordinates on convex polygons suitable for standard finite element analysis. Our analysis is based on providing a uniform bound on the gradient of the mean value functions for all convex polygons of diameter one satisfying certain simple geometric restrictions. This work makes rigorous an observed practical advantage of the mean value coordinates: unlike Wachspress coordinates, the gradient of the mean value coordinates does not become large as interior angles of the polygon approach π.
Conformal array design on arbitrary polygon surface with transformation optics
International Nuclear Information System (INIS)
Deng, Li; Hong, Weijun; Zhu, Jianfeng; Peng, Biao; Li, Shufang; Wu, Yongle
2016-01-01
A transformation-optics based method to design a conformal antenna array on an arbitrary polygon surface is proposed and demonstrated in this paper. This conformal antenna array can be adjusted to behave equivalently as a uniformly spaced linear array by applying an appropriate transformation medium. An typical example of general arbitrary polygon conformal arrays, not limited to circular array, is presented, verifying the proposed approach. In summary, the novel arbitrary polygon surface conformal array can be utilized in array synthesis and beam-forming, maintaining all benefits of linear array.
Alabama ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for dolphins and manatees in Alabama. Vector polygons in this data set represent marine mammal distribution...
Western Alaska ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for seals, whales, dolphins, walruses, and Steller sea lions in Western Alaska. Vector polygons in this...
American Samoa ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for whales and dolphins in American Samoa. Vector polygons in this data set represent marine mammal...
Columbia River ESI: NWI (National Wetlands Inventory - Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the wetlands of Columbia River classified according to the Environmental Sensitivity Index (ESI) classification...
Coastal Resources Atlas: Long Island: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, anadromous, and freshwater fish species for Long Island, New York. Vector polygons...
Coastal Resources Atlas: Long Island: REPTILES (Reptile and Amphibian Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for sea turtles, estuarine turtles, and amphibians for Long Island, New York. Vector polygons in this data...
Louisiana ESI: T_MAMMAL (Terrestrial Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for terrestrial mammals in Louisiana. Vector polygons in this data set represent terrestrial mammal...
North Slope, Alaska ESI: T_MAMMAL (Terrestrial Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for brown bears, caribou, and muskoxen for the North Slope, Alaska. Vector polygons in this data set...
Virginia ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for dolphin, seals, whales, and porpoise in Virginia. Vector polygons in this data set represent marine...
North Slope, Alaska ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for whales, seals, walruses, and polar bears for the North Slope of Alaska. Vector polygons in this data...
Shinarump Channel Polygons, North Central AUM Region, 1964, USDOE
U.S. Environmental Protection Agency — This is a polygon shapefile that provides Shinarump channels compiled and mapped by Young and Malan (1964) in the Monument Valley District, San Juan County, Utah,...
Cook Inlet and Kenai Peninsula, Alaska ESI: INDEX (Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries used in the creation of the Environmental Sensitivity Index (ESI) for Cook Inlet and Kenai...
Southeast Alaska ESI: T_MAMMAL (Terrestrial Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains biological resource data for brown bears in Southeast Alaska. Vector polygons in this data set represent locations of bear concentrations....
American Samoa ESI: REPTILES (Reptile and Amphibian Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for sea turtles in American Samoa. Vector polygons in this data set represent sea turtle nesting and...
Columbia River ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for Steller sea lions, harbor seals, and California sea lions in Columbia River. Vector polygons in this...
Coastal Resources Atlas: Long Island: INVERT (Invertebrate Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for coastal, estuarine, and marine invertebrate species for Long Island, New York. Vector polygons in this...
Cook Inlet and Kenai Peninsula, Alaska ESI: INVERT (Invertebrate Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains biological resource data for razor clams in Cook Inlet and Kenai Peninsula, Alaska. Vector polygons in this data set represent locations of...
Columbia River ESI: REPTILES (Reptile and Amphibian Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for western pond turtles and western painted turtles in Columbia River. Vector polygons in this data set...
Cook Inlet and Kenai Peninsula, Alaska ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains biological resource data for herring spawning areas in Cook Inlet and Kenai Peninsula, Alaska. Vector polygons in this data set represent...
PNW River Reach Files -- 1:100k Waterbodies (polygons)
Pacific States Marine Fisheries Commission — This feature class includes the POLYGON waterbody features from the 2001 version of the PNW River Reach files Arc/INFO coverage. Separate, companion feature classes...
North Slope, Alaska ESI: BIOINDEX (Biological Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the quad boundaries of the 1:250,000 USGS topographic quadrangles. These boundaries represent the extent of the...
Louisiana ESI: LG_INDEX (Large Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all the hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
Structural characterization of the packings of granular regular polygons.
Wang, Chuncheng; Dong, Kejun; Yu, Aibing
2015-12-01
By using a recently developed method for discrete modeling of nonspherical particles, we simulate the random packings of granular regular polygons with three to 11 edges under gravity. The effects of shape and friction on the packing structures are investigated by various structural parameters, including packing fraction, the radial distribution function, coordination number, Voronoi tessellation, and bond-orientational order. We find that packing fraction is generally higher for geometrically nonfrustrated regular polygons, and can be increased by the increase of edge number and decrease of friction. The changes of packing fraction are linked with those of the microstructures, such as the variations of the translational and orientational orders and local configurations. In particular, the free areas of Voronoi tessellations (which are related to local packing fractions) can be described by log-normal distributions for all polygons. The quantitative analyses establish a clearer picture for the packings of regular polygons.
Polygon formation and surface flow on a rotating fluid surface
DEFF Research Database (Denmark)
Bergmann, Raymond; Tophøj, Laust Emil Hjerrild; Homan, T. A. M.
2011-01-01
We present a study of polygons forming on the free surface of a water flow confined to a stationary cylinder and driven by a rotating bottom plate as described by Jansson et al. (Phys. Rev. Lett., vol. 96, 2006, 174502). In particular, we study the case of a triangular structure, either completely...... there the symmetry breaking proceeds like a low-dimensional linear instability. We show that the circular state and the unstable manifold connecting it with the polygon solution are universal in the sense that very different initial conditions lead to the same circular state and unstable manifold. For a wet triangle......, we measure the surface flows by particle image velocimetry (PIV) and show that there are three vortices present, but that the strength of these vortices is far too weak to account for the rotation velocity of the polygon. We show that partial blocking of the surface flow destroys the polygons and re...
The unusual asymptotics of three-sided prudent polygons
International Nuclear Information System (INIS)
Beaton, Nicholas R; Guttmann, Anthony J; Flajolet, Philippe
2010-01-01
We have studied the area-generating function of prudent polygons on the square lattice. Exact solutions are obtained for the generating function of two-sided and three-sided prudent polygons, and a functional equation is found for four-sided prudent polygons. This is used to generate series coefficients in polynomial time, and these are analysed to determine the asymptotics numerically. A careful asymptotic analysis of the three-sided polygons produces a most surprising result. A transcendental critical exponent is found, and the leading amplitude is not quite a constant, but is a constant plus a small oscillatory component with an amplitude approximately 10 -8 times that of the leading amplitude. This effect cannot be seen by any standard numerical analysis, but it may be present in other models. If so, it changes our whole view of the asymptotic behaviour of lattice models. (fast track communication)
Average size of random polygons with fixed knot topology.
Matsuda, Hiroshi; Yao, Akihisa; Tsukahara, Hiroshi; Deguchi, Tetsuo; Furuta, Ko; Inami, Takeo
2003-07-01
We have evaluated by numerical simulation the average size R(K) of random polygons of fixed knot topology K=,3(1),3(1) musical sharp 4(1), and we have confirmed the scaling law R(2)(K) approximately N(2nu(K)) for the number N of polygonal nodes in a wide range; N=100-2200. The best fit gives 2nu(K) approximately 1.11-1.16 with good fitting curves in the whole range of N. The estimate of 2nu(K) is consistent with the exponent of self-avoiding polygons. In a limited range of N (N greater, similar 600), however, we have another fit with 2nu(K) approximately 1.01-1.07, which is close to the exponent of random polygons.
Bristol Bay, Alaska Subarea ESI: INDEX (Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all the hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
Maryland ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for seals, whales, porpoise, and dolphin in Maryland. Vector polygons in this data set represent marine...
Alabama ESI: T_MAMMAL (Terrestrial Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for Alabama and Perdido Key beach mice in Alabama. Vector polygons in this data set represent the rare...
Morphometric analysis of the arteries of Willis Polygon
Directory of Open Access Journals (Sweden)
Canaz Huseyin
2018-03-01
Full Text Available Objective: Willis polygon forms the basis of the arterial circulation of the cerebrum. Willis polygon is a vascular structure whom variations are not rare. Knowledge of the anatomy and preservation of its integrity is crucial for performing neurovascular surgery and intracranial tumour surgery. Because of the important vascular and neurological structures, approaches to this region are considered extremely risky. One of the main variations in-person basis is the diameter differences of the arteries, which forms Willis polygon, between the left and right hemispheres. About structure and variations, studies of Rhoton and Yasargil had formed the touchstone. Our aim is to contribute to the literature and clinical studies, to be done in the future, by comparing our results with previous studies about variations and morphometric features of Willis polygon.
Coastal Resources Atlas: Long Island: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Long Island,...
North Slope, Alaska ESI: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for the North...
Columbia River ESI: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Columbia...
Bristol Bay, Alaska Subarea ESI: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for the Bristol...
Spectral segmentation of polygonized images with normalized cuts
Energy Technology Data Exchange (ETDEWEB)
Matsekh, Anna [Los Alamos National Laboratory; Skurikhin, Alexei [Los Alamos National Laboratory; Rosten, Edward [UNIV OF CAMBRIDGE
2009-01-01
We analyze numerical behavior of the eigenvectors corresponding to the lowest eigenvalues of the generalized graph Laplacians arising in the Normalized Cuts formulations of the image segmentation problem on coarse polygonal grids.
Rotating polygon instability of a swirling free surface flow
DEFF Research Database (Denmark)
Tophøj, Laust Emil Hjerrild; Bohr, Tomas; Mougel, J.
2013-01-01
We explain the rotating polygon instability on a swirling fluid surface [G. H. Vatistas, J. Fluid Mech. 217, 241 (1990)JFLSA70022-1120 and Jansson et al., Phys. Rev. Lett. 96, 174502 (2006)PRLTAO0031-9007] in terms of resonant interactions between gravity waves on the outer part of the surface...... behavior near the corners), and indeed we show that we can obtain the polygons transiently by violently stirring liquid nitrogen in a hot container....
NSGIC State | GIS Inventory — SILURIAN_REEF_POLYGONS_MM54_IN is a polygon shapefile that shows the general locations of Silurian rock reef bank formations in Indiana. These data include two major...
Directory of Open Access Journals (Sweden)
Carles eMarco Llorca
2014-04-01
Full Text Available bZIPs and WRKYs are two important plant transcription factor families regulating diverse developmental and stress-related processes. Since a partial overlap in these biological processes is obvious, it can be speculated that they fulfill non-redundant functions in a complex regulatory network. Here, we focus on the regulatory mechanisms that are so far described for bZIPs and WRKYs. bZIP factors need to heterodimerize for DNA-binding and regulation of transcription, and based on a bioinformatics approach, bZIPs can build up more than the double of protein interactions than WRKYs. In contrast, an enrichment of the WRKY DNA-binding motifs can be found in WRKY promoters, a phenomenon which is not observed for the bZIP family. Thus, the two transcription factor families follow two different functional strategies in which WRKYs regulate each other’s transcription in a transcriptional network whereas bZIP action relies on intensive heterodimerization.
Using Wireless Pedometers to Measure Children’s Physical Activity: How Reliable is the Fitbit Zip?
Directory of Open Access Journals (Sweden)
Tingting Xu
2017-07-01
Full Text Available The purpose of this study is to examine the reliability of wireless pedometers in measuring elementary school children’s physical activity. Activity measurement using a wireless pedometer Fitbit ZipTM was compared to activity measurement using Yamax Digi-WalkerTM SW701 for a group of randomly selected 25 children in Grades 3, 4, and 5. Fitbit ZipTM wireless pedometers were found to have an appropriate degree (Nunnally & Bernstein, 1994 of accuracy and reliability compared to the Yamax Digi-WalkerTM SW701 pedometer. The Fitbit ZipTM wireless pedometer collected more step counts than the Yamax Digi-WalkerTM SW701 pedometer; however, the difference was not statistically significant. Participants reported that they preferred wearing the Fitbit ZipTM to the Yamax Digi-WalkerTM SW701 because the Fitbit ZipTM was more comfortable to wear and less likely to fall off. Participants also reported being more motivated to move while wearing the Fitbit ZipTM.
Directory of Open Access Journals (Sweden)
Tolunay Beker Aydemir
Full Text Available ZIP14 (slc39A14 is a zinc transporter induced in response to pro-inflammatory stimuli. ZIP14 induction accompanies the reduction in serum zinc (hypozincemia of acute inflammation. ZIP14 can transport Zn(2+ and non-transferrin-bound Fe(2+ in vitro. Using a Zip14(-/- mouse model we demonstrated that ZIP14 was essential for control of phosphatase PTP1B activity and phosphorylation of c-Met during liver regeneration. In the current studies, a global screening of ZIP transporter gene expression in response to LPS-induced endotoxemia was conducted. Following LPS, Zip14 was the most highly up-regulated Zip transcript in liver, but also in white adipose tissue and muscle. Using ZIP14(-/- mice we show that ZIP14 contributes to zinc absorption from the gastrointestinal tract directly or indirectly as zinc absorption was decreased in the KOs. In contrast, Zip14(-/- mice absorbed more iron. The Zip14 KO mice did not exhibit hypozincemia following LPS, but do have hypoferremia. Livers of Zip14-/- mice had increased transcript abundance for hepcidin, divalent metal transporter-1, ferritin and transferrin receptor-1 and greater accumulation of iron. The Zip14(-/- phenotype included greater body fat, hypoglycemia and higher insulin levels, as well as increased liver glucose and greater phosphorylation of the insulin receptor and increased GLUT2, SREBP-1c and FASN expression. The Zip14 KO mice exhibited decreased circulating IL-6 with increased hepatic SOCS-3 following LPS, suggesting SOCS-3 inhibited insulin signaling which produced the hypoglycemia in this genotype. The results are consistent with ZIP14 ablation yielding abnormal labile zinc pools which lead to increased SOCS-3 production through G-coupled receptor activation and increased cAMP production as well as signaled by increased pSTAT3 via the IL-6 receptor, which inhibits IRS 1/2 phosphorylation. Our data show the role of ZIP14 in the hepatocyte is multi-functional since zinc and iron trafficking are
Image segmentation by hierarchial agglomeration of polygons using ecological statistics
Prasad, Lakshman; Swaminarayan, Sriram
2013-04-23
A method for rapid hierarchical image segmentation based on perceptually driven contour completion and scene statistics is disclosed. The method begins with an initial fine-scale segmentation of an image, such as obtained by perceptual completion of partial contours into polygonal regions using region-contour correspondences established by Delaunay triangulation of edge pixels as implemented in VISTA. The resulting polygons are analyzed with respect to their size and color/intensity distributions and the structural properties of their boundaries. Statistical estimates of granularity of size, similarity of color, texture, and saliency of intervening boundaries are computed and formulated into logical (Boolean) predicates. The combined satisfiability of these Boolean predicates by a pair of adjacent polygons at a given segmentation level qualifies them for merging into a larger polygon representing a coarser, larger-scale feature of the pixel image and collectively obtains the next level of polygonal segments in a hierarchy of fine-to-coarse segmentations. The iterative application of this process precipitates textured regions as polygons with highly convolved boundaries and helps distinguish them from objects which typically have more regular boundaries. The method yields a multiscale decomposition of an image into constituent features that enjoy a hierarchical relationship with features at finer and coarser scales. This provides a traversable graph structure from which feature content and context in terms of other features can be derived, aiding in automated image understanding tasks. The method disclosed is highly efficient and can be used to decompose and analyze large images.
Water polygons in high-resolution protein crystal structures.
Lee, Jonas; Kim, Sung-Hou
2009-07-01
We have analyzed the interstitial water (ISW) structures in 1500 protein crystal structures deposited in the Protein Data Bank that have greater than 1.5 A resolution with less than 90% sequence similarity with each other. We observed varieties of polygonal water structures composed of three to eight water molecules. These polygons may represent the time- and space-averaged structures of "stable" water oligomers present in liquid water, and their presence as well as relative population may be relevant in understanding physical properties of liquid water at a given temperature. On an average, 13% of ISWs are localized enough to be visible by X-ray diffraction. Of those, averages of 78% are water molecules in the first water layer on the protein surface. Of the localized ISWs beyond the first layer, almost half of them form water polygons such as trigons, tetragons, as well as expected pentagons, hexagons, higher polygons, partial dodecahedrons, and disordered networks. Most of the octagons and nanogons are formed by fusion of smaller polygons. The trigons are most commonly observed. We suggest that our observation provides an experimental basis for including these water polygon structures in correlating and predicting various water properties in liquid state.
Vigorous convection as the explanation for Pluto's polygonal terrain.
Trowbridge, A J; Melosh, H J; Steckloff, J K; Freed, A M
2016-06-02
Pluto's surface is surprisingly young and geologically active. One of its youngest terrains is the near-equatorial region informally named Sputnik Planum, which is a topographic basin filled by nitrogen (N2) ice mixed with minor amounts of CH4 and CO ices. Nearly the entire surface of the region is divided into irregular polygons about 20-30 kilometres in diameter, whose centres rise tens of metres above their sides. The edges of this region exhibit bulk flow features without polygons. Both thermal contraction and convection have been proposed to explain this terrain, but polygons formed from thermal contraction (analogous to ice-wedges or mud-crack networks) of N2 are inconsistent with the observations on Pluto of non-brittle deformation within the N2-ice sheet. Here we report a parameterized convection model to compute the Rayleigh number of the N2 ice and show that it is vigorously convecting, making Rayleigh-Bénard convection the most likely explanation for these polygons. The diameter of Sputnik Planum's polygons and the dimensions of the 'floating mountains' (the hills of of water ice along the edges of the polygons) suggest that its N2 ice is about ten kilometres thick. The estimated convection velocity of 1.5 centimetres a year indicates a surface age of only around a million years.
ZipA binds to FtsZ with high affinity and enhances the stability of FtsZ protofilaments.
Directory of Open Access Journals (Sweden)
Anuradha Kuchibhatla
Full Text Available A bacterial membrane protein ZipA that tethers FtsZ to the membrane is known to promote FtsZ assembly. In this study, the binding of ZipA to FtsZ was monitored using fluorescence spectroscopy. ZipA was found to bind to FtsZ with high affinities at three different (6.0, 6.8 and 8.0 pHs, albeit the binding affinity decreased with increasing pH. Further, thick bundles of FtsZ protofilaments were observed in the presence of ZipA under the pH conditions used in this study indicating that ZipA can promote FtsZ assembly and stabilize FtsZ polymers under unfavorable conditions. Bis-ANS, a hydrophobic probe, decreased the interaction of FtsZ and ZipA indicating that the interaction between FtsZ and ZipA is hydrophobic in nature. ZipA prevented the dilution induced disassembly of FtsZ polymers suggesting that it stabilizes FtsZ protofilaments. Fluorescein isothiocyanate-labeled ZipA was found to be uniformly distributed along the length of the FtsZ protofilaments indicating that ZipA stabilizes FtsZ protofilaments by cross-linking them.
Directory of Open Access Journals (Sweden)
Xianguang Nie
2014-06-01
Full Text Available Protein–protein interactions are important for the molecular understanding of the biological processes of proteins. The dimerization of bZIPs (basic leucine zipper proteins is involved in modifying binding site specificities, altering dimer stability, and permitting a new set of specific protein-to-protein interactions to occur at the promoter. In the present study, we studied the whether ThbZIP1 form homo- and heterodimers using the yeast two-hybrid method. Five bZIP genes were cloned from Tamarix hispida to investigate their interaction with ThbZIP1. Our results showed that ThbZIP1 can form homodimers with itself, and three out of five bZIPs could interact with the ThbZIP1 protein to form heterodimers. Real-time RT-PCR results suggested that these ThbZIPs can all respond to abiotic stresses and abscisic acid (ABA, and shared very similar expression patterns in response to NaCl, ABA or PEG6000. Subcellular localization studies showed that all ThbZIPs are targeted to the nucleus. Our results showed that ThbZIP1 are dimeric proteins, which can form homo- or heterodimers.
Wang, Yucheng; Gao, Caiqiu; Liang, Yenan; Wang, Chao; Yang, Chuanping; Liu, Guifeng
2010-02-15
Basic leucine zipper proteins (bZIPs) are transcription factors that bind abscisic acid (ABA)-responsive elements (ABREs) and enable plants to withstand adverse environmental conditions. In the present study, a novel bZIP gene, ThbZIP1 was cloned from Tamarix hispida. Expression studies in T. hispida showed differential regulation of ThbZIP1 in response to treatment with NaCl, polyethylene glycol (PEG) 6000, NaHCO(3), and CdCl(2), suggesting that ThbZIP1 is involved in abiotic stress responses. To identify the physiological responses mediated by ThbZIP1, transgenic tobacco plants overexpressing exogenous ThbZIP1 were generated. Various physiological parameters related to salt stress were measured and compared between transgenic and wild type (WT) plants. Our results indicate that overexpression of ThbZIP1 can enhance the activity of both peroxidase (POD) and superoxide dismutase (SOD), and increase the content of soluble sugars and soluble proteins under salt stress conditions. These results suggest that ThbZIP1 contributes to salt tolerance by mediating signaling through multiple physiological pathways. Furthermore, ThbZIP1 confers stress tolerance to plants by enhancing reactive oxygen species (ROS) scavenging, facilitating the accumulation of compatible osmolytes, and inducing and/or enhancing the biosynthesis of soluble proteins. Copyright 2009 Elsevier GmbH. All rights reserved.
Slc39a7/zip7 plays a critical role in development and zinc homeostasis in zebrafish.
Directory of Open Access Journals (Sweden)
Guang Yan
Full Text Available BACKGROUND: Slc39a7/Zip7, also known as Ke4, is a member of solute carrier family 39 (Slc39a and plays a critical role in regulating cell growth and death. Because the function of Zip7 in vivo was unclear, the present study investigated the function of zip7 in vertebrate development and zinc metabolism using zebrafish as a model organism. PRINCIPAL FINDING: Using real-time PCR to determine the gene expression pattern of zip7 during zebrafish development, we found that zip7 mRNA is expressed throughout embryonic development and into maturity. Interestingly, whole mount in situ hybridization revealed that while zip7 mRNA is ubiquitously expressed until 12 hours post-fertilization (hpf; at 24 hpf and beyond, zip7 mRNA was specifically detected only in eyes. Morpholino-antisense (MO gene knockdown assay revealed that downregulation of zip7 expression resulted in several morphological defects in zebrafish including decreased head size, smaller eyes, shorter palates, and shorter and curved spinal cords. Analysis by synchrotron radiation X-ray fluorescence (SR-XRF showed reduced concentrations of zinc in brain, eyes, and gills of zip7-MO-injected embryos. Furthermore, incubation of the zip7 knockdown embryos in a zinc-supplemented solution was able to rescue the MO-induced morphological defects. SIGNIFICANCE: Our data suggest that zip7 is required for eye, brain, and skeleton formation during early embryonic development in zebrafish. Moreover, zinc supplementation can partially rescue defects resulting from zip7 gene knockdown. Taken together, our data provide critical insight into a novel function of zip7 in development and zinc homeostasis in vivo in zebrafish.
Realistic roofs over a rectilinear polygon
Ahn, Heekap
2013-11-01
Given a simple rectilinear polygon P in the xy-plane, a roof over P is a terrain over P whose faces are supported by planes through edges of P that make a dihedral angle π/4 with the xy-plane. According to this definition, some roofs may have faces isolated from the boundary of P or even local minima, which are undesirable for several practical reasons. In this paper, we introduce realistic roofs by imposing a few additional constraints. We investigate the geometric and combinatorial properties of realistic roofs and show that the straight skeleton induces a realistic roof with maximum height and volume. We also show that the maximum possible number of distinct realistic roofs over P is ((n-4)(n-4)/4 /2⌋) when P has n vertices. We present an algorithm that enumerates a combinatorial representation of each such roof in O(1) time per roof without repetition, after O(n4) preprocessing time. We also present an O(n5)-time algorithm for computing a realistic roof with minimum height or volume. © 2013 Elsevier B.V.
A new convexity measure for polygons.
Zunic, Jovisa; Rosin, Paul L
2004-07-01
Abstract-Convexity estimators are commonly used in the analysis of shape. In this paper, we define and evaluate a new convexity measure for planar regions bounded by polygons. The new convexity measure can be understood as a "boundary-based" measure and in accordance with this it is more sensitive to measured boundary defects than the so called "area-based" convexity measures. When compared with the convexity measure defined as the ratio between the Euclidean perimeter of the convex hull of the measured shape and the Euclidean perimeter of the measured shape then the new convexity measure also shows some advantages-particularly for shapes with holes. The new convexity measure has the following desirable properties: 1) the estimated convexity is always a number from (0, 1], 2) the estimated convexity is 1 if and only if the measured shape is convex, 3) there are shapes whose estimated convexity is arbitrarily close to 0, 4) the new convexity measure is invariant under similarity transformations, and 5) there is a simple and fast procedure for computing the new convexity measure.
Bifurcation of self-folded polygonal bilayers
Abdullah, Arif M.; Braun, Paul V.; Hsia, K. Jimmy
2017-09-01
Motivated by the self-assembly of natural systems, researchers have investigated the stimulus-responsive curving of thin-shell structures, which is also known as self-folding. Self-folding strategies not only offer possibilities to realize complicated shapes but also promise actuation at small length scales. Biaxial mismatch strain driven self-folding bilayers demonstrate bifurcation of equilibrium shapes (from quasi-axisymmetric doubly curved to approximately singly curved) during their stimulus-responsive morphing behavior. Being a structurally instable, bifurcation could be used to tune the self-folding behavior, and hence, a detailed understanding of this phenomenon is appealing from both fundamental and practical perspectives. In this work, we investigated the bifurcation behavior of self-folding bilayer polygons. For the mechanistic understanding, we developed finite element models of planar bilayers (consisting of a stimulus-responsive and a passive layer of material) that transform into 3D curved configurations. Our experiments with cross-linked Polydimethylsiloxane samples that change shapes in organic solvents confirmed our model predictions. Finally, we explored a design scheme to generate gripper-like architectures by avoiding the bifurcation of stimulus-responsive bilayers. Our research contributes to the broad field of self-assembly as the findings could motivate functional devices across multiple disciplines such as robotics, artificial muscles, therapeutic cargos, and reconfigurable biomedical devices.
Directory of Open Access Journals (Sweden)
Xueyin Li
2016-11-01
Full Text Available Extensive studies in Arabidopsis and rice have demonstrated that Subgroup-A members of the bZIP transcription factor family play important roles in plant responses to multiple abiotic stresses. Although common wheat (Triticum aestivum is one of the most widely cultivated and consumed food crops in the world, there are limited investigations into Subgroup A of the bZIP family in wheat. In this study, we performed bioinformatic analyses of the 41 Subgroup-A members of the wheat bZIP family. Phylogenetic and conserved motif analyses showed that most of the Subgroup-A bZIP proteins involved in abiotic stress responses of wheat, Arabidopsis and rice clustered in Clade A1 of the phylogenetic tree, and shared a majority of conserved motifs, suggesting the potential importance of Clade-A1 members in abiotic stress responses. Gene structure analysis showed that TabZIP genes with close phylogenetic relationships tended to possess similar exon-intron compositions, and the positions of introns in the hinge regions of the bZIP domains were highly conserved, whereas introns in the leucine zipper regions were at variable positions. Additionally, eleven groups of homologs and two groups of tandem paralogs were also identified in Subgroup A of the wheat bZIP family. Expression profiling analysis indicated that most Subgroup-A TabZIP genes were responsive to abscisic acid and various abiotic stress treatments. TabZIP27, TabZIP74, TabZIP138 and TabZIP174 proteins were localized in the nucleus of wheat protoplasts, whereas TabZIP9-GFP fusion protein was simultaneously present in the nucleus, cytoplasm and cell membrane. Transgenic Arabidopsis overexpressing TabZIP174 displayed increased seed germination rates and primary root lengths under drought treatments. Overexpression of TabZIP174 in transgenic Arabidopsis conferred enhanced drought tolerance, and transgenic plants exhibited lower water loss rates, higher survival rates, higher proline, soluble sugar and leaf
Li, Xueyin; Feng, Biane; Zhang, Fengjie; Tang, Yimiao; Zhang, Liping; Ma, Lingjian; Zhao, Changping; Gao, Shiqing
2016-01-01
Extensive studies in Arabidopsis and rice have demonstrated that Subgroup-A members of the bZIP transcription factor family play important roles in plant responses to multiple abiotic stresses. Although common wheat (Triticum aestivum) is one of the most widely cultivated and consumed food crops in the world, there are limited investigations into Subgroup A of the bZIP family in wheat. In this study, we performed bioinformatic analyses of the 41 Subgroup-A members of the wheat bZIP family. Phylogenetic and conserved motif analyses showed that most of the Subgroup-A bZIP proteins involved in abiotic stress responses of wheat, Arabidopsis, and rice clustered in Clade A1 of the phylogenetic tree, and shared a majority of conserved motifs, suggesting the potential importance of Clade-A1 members in abiotic stress responses. Gene structure analysis showed that TabZIP genes with close phylogenetic relationships tended to possess similar exon–intron compositions, and the positions of introns in the hinge regions of the bZIP domains were highly conserved, whereas introns in the leucine zipper regions were at variable positions. Additionally, eleven groups of homologs and two groups of tandem paralogs were also identified in Subgroup A of the wheat bZIP family. Expression profiling analysis indicated that most Subgroup-A TabZIP genes were responsive to abscisic acid and various abiotic stress treatments. TabZIP27, TabZIP74, TabZIP138, and TabZIP174 proteins were localized in the nucleus of wheat protoplasts, whereas TabZIP9-GFP fusion protein was simultaneously present in the nucleus, cytoplasm, and cell membrane. Transgenic Arabidopsis overexpressing TabZIP174 displayed increased seed germination rates and primary root lengths under drought treatments. Overexpression of TabZIP174 in transgenic Arabidopsis conferred enhanced drought tolerance, and transgenic plants exhibited lower water loss rates, higher survival rates, higher proline, soluble sugar, and leaf chlorophyll
Current 5-Digit ZIP Code Tabulation Areas (ZCTAs) for Quay County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Current 3-Digit ZIP Code Tabulation Areas (ZCTAs) for Guadalupe County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Current 3-Digit ZIP Code Tabulation Areas (ZCTAs) for Union County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Current 3-Digit ZIP Code Tabulation Areas (ZCTAs) for Torrance County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Current 3-Digit ZIP Code Tabulation Areas (ZCTAs) for Sierra County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Current 5-Digit ZIP Code Tabulation Areas (ZCTAs) for Guadalupe County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Current 5-Digit ZIP Code Tabulation Areas (ZCTAs) for Valencia County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Current 3-Digit ZIP Code Tabulation Areas (ZCTAs) for Roosevelt County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
New Mexico, 2010 Census 5-Digit ZIP Code Tabulation Area (ZCTA5)
Earth Data Analysis Center, University of New Mexico — The TIGER/Line Files are shapefiles and related database files (.dbf) that are an extract of selected geographic and cartographic information from the U.S. Census...
Czech Academy of Sciences Publication Activity Database
Gibalová, A.; Steinbachová, L.; Hafidh, S.; Bláhová, Veronika; Gadiou, Z.; Michailidis, Ch.; Müller, K.; Pleskot, Roman; Dupľáková, N.; Honys, D.
2017-01-01
Roč. 30, č. 1 (2017), s. 1-17 ISSN 2194-7953 Institutional support: RVO:67985823 ; RVO:61388963 Keywords : bZIP * transcription factors * regulatory network * male gametophyte * Y2H * pollen development Subject RIV: ED - Physiology; CE - Biochemistry (UOCHB-X) OBOR OECD: Physiology (including cytology); Biochemistry and molecular biology (UOCHB-X) Impact factor: 2.629, year: 2016
Conversion of ICRP male reference phantom to polygon-surface phantom
International Nuclear Information System (INIS)
Yeom, Yeon Soo; Han, Min Cheol; Kim, Chan Hyeong; Jeong, Jong Hwi
2013-01-01
The International Commission on Radiological Protection (ICRP) reference phantoms, developed based on computed tomography images of human bodies, provide much more realism of human anatomy than the previously used MIRD5 (Medical Internal Radiation Dose) mathematical phantoms. It has been, however, realized that the ICRP reference phantoms have some critical limitations showing a considerable amount of holes for the skin and wall organs mainly due to the nature of voxels of which the phantoms are made, especially due to their low voxel resolutions. To address this problem, we are planning to develop the polygon-surface version of ICRP reference phantoms by directly converting the ICRP reference phantoms (voxel phantoms) to polygon-surface phantoms. The objective of this preliminary study is to see if it is indeed possible to construct the high-quality polygon-surface phantoms based on the ICRP reference phantoms maintaining identical organ morphology and also to identify any potential issues, and technologies to address these issues, in advance. For this purpose, in the present study, the ICRP reference male phantom was roughly converted to a polygon-surface phantom. Then, the constructed phantom was implemented in Geant4, Monte Carlo particle transport code, for dose calculations, and the calculated dose values were compared with those of the original ICRP reference phantom to see how much the calculated dose values are sensitive to the accuracy of the conversion process. The results of the present study show that it is certainly possible to convert the ICRP reference phantoms to surface phantoms with enough accuracy. In spite of using relatively less resources (<2 man-months), we were able to construct the polygon-surface phantom with the organ masses perfectly matching the ICRP reference values. The analysis of the calculated dose values also implies that the dose values are indeed not very sensitive to the detailed morphology of the organ models in the phantom
A Petunia Homeodomain-Leucine Zipper Protein, PhHD-Zip, Plays an Important Role in Flower Senescence
Chang, Xiaoxiao; Donnelly, Linda; Sun, Daoyang; Rao, Jingping; Reid, Michael S.; Jiang, Cai-Zhong
2014-01-01
Flower senescence is initiated by developmental and environmental signals, and regulated by gene transcription. A homeodomain-leucine zipper transcription factor, PhHD-Zip, is up-regulated during petunia flower senescence. Virus-induced gene silencing of PhHD-Zip extended flower life by 20% both in unpollinated and pollinated flowers. Silencing PhHD-Zip also dramatically reduced ethylene production and the abundance of transcripts of genes involved in ethylene (ACS, ACO), and ABA (NCED) biosynthesis. Abundance of transcripts of senescence-related genes (SAG12, SAG29) was also dramatically reduced in the silenced flowers. Over-expression of PhHD-Zip accelerated petunia flower senescence. Furthermore, PhHD-Zip transcript abundance in petunia flowers was increased by application of hormones (ethylene, ABA) and abiotic stresses (dehydration, NaCl and cold). Our results suggest that PhHD-Zip plays an important role in regulating petunia flower senescence. PMID:24551088
HvZIP7 mediates zinc accumulation in barley (Hordeum vulgare) at moderately high zinc supply
DEFF Research Database (Denmark)
Tiong, Jingwen; Mcdonald, Glenn K.; Genc, Yusuf
2014-01-01
Summary: High expression of zinc (Zn)-regulated, iron-regulated transporter-like protein (ZIP) genes increases root Zn uptake in dicots, leading to high accumulation of Zn in shoots. However, none of the ZIP genes tested previously in monocots could enhance shoot Zn accumulation. In this report...... were also generated to further understand the functions of HvZIP7 in metal transport. HvZIP7 is strongly induced by Zn deficiency, primarily in vascular tissues of roots and leaves, and its protein was localized in the plasma membrane. These properties are similar to its closely related homologs...... in dicots. Overexpression of HvZIP7 in barley plants increased Zn uptake when moderately high concentrations of Zn were supplied. Significantly, there was a specific enhancement of shoot Zn accumulation, with no measurable increase in iron (Fe), manganese (Mn), copper (Cu) or cadmium (Cd). HvZIP7 displays...
Chang, Xiaoxiao; Donnelly, Linda; Sun, Daoyang; Rao, Jingping; Reid, Michael S; Jiang, Cai-Zhong
2014-01-01
Flower senescence is initiated by developmental and environmental signals, and regulated by gene transcription. A homeodomain-leucine zipper transcription factor, PhHD-Zip, is up-regulated during petunia flower senescence. Virus-induced gene silencing of PhHD-Zip extended flower life by 20% both in unpollinated and pollinated flowers. Silencing PhHD-Zip also dramatically reduced ethylene production and the abundance of transcripts of genes involved in ethylene (ACS, ACO), and ABA (NCED) biosynthesis. Abundance of transcripts of senescence-related genes (SAG12, SAG29) was also dramatically reduced in the silenced flowers. Over-expression of PhHD-Zip accelerated petunia flower senescence. Furthermore, PhHD-Zip transcript abundance in petunia flowers was increased by application of hormones (ethylene, ABA) and abiotic stresses (dehydration, NaCl and cold). Our results suggest that PhHD-Zip plays an important role in regulating petunia flower senescence.
Directory of Open Access Journals (Sweden)
Xiaoxiao Chang
Full Text Available Flower senescence is initiated by developmental and environmental signals, and regulated by gene transcription. A homeodomain-leucine zipper transcription factor, PhHD-Zip, is up-regulated during petunia flower senescence. Virus-induced gene silencing of PhHD-Zip extended flower life by 20% both in unpollinated and pollinated flowers. Silencing PhHD-Zip also dramatically reduced ethylene production and the abundance of transcripts of genes involved in ethylene (ACS, ACO, and ABA (NCED biosynthesis. Abundance of transcripts of senescence-related genes (SAG12, SAG29 was also dramatically reduced in the silenced flowers. Over-expression of PhHD-Zip accelerated petunia flower senescence. Furthermore, PhHD-Zip transcript abundance in petunia flowers was increased by application of hormones (ethylene, ABA and abiotic stresses (dehydration, NaCl and cold. Our results suggest that PhHD-Zip plays an important role in regulating petunia flower senescence.
Sequential and Parallel Algorithms for Finding a Maximum Convex Polygon
DEFF Research Database (Denmark)
Fischer, Paul
1997-01-01
This paper investigates the problem where one is given a finite set of n points in the plane each of which is labeled either ?positive? or ?negative?. We consider bounded convex polygons, the vertices of which are positive points and which do not contain any negative point. It is shown how...... such a polygon which is maximal with respect to area can be found in time O(n³ log n). With the same running time one can also find such a polygon which contains a maximum number of positive points. If, in addition, the number of vertices of the polygon is restricted to be at most M, then the running time...... becomes O(M n³ log n). It is also shown how to find a maximum convex polygon which contains a given point in time O(n³ log n). Two parallel algorithms for the basic problem are also presented. The first one runs in time O(n log n) using O(n²) processors, the second one has polylogarithmic time but needs O...
Wang, Jie-Chen; Xu, Heng; Zhu, Ying; Liu, Qiao-Quan; Cai, Xiu-Ling
2013-08-01
Starch composition and the amount in endosperm, both of which contribute dramatically to seed yield, cooking quality, and taste in cereals, are determined by a series of complex biochemical reactions. However, the mechanism regulating starch biosynthesis in cereal seeds is not well understood. This study showed that OsbZIP58, a bZIP transcription factor, is a key transcriptional regulator controlling starch synthesis in rice endosperm. OsbZIP58 was expressed mainly in endosperm during active starch synthesis. osbzip58 null mutants displayed abnormal seed morphology with altered starch accumulation in the white belly region and decreased amounts of total starch and amylose. Moreover, osbzip58 had a higher proportion of short chains and a lower proportion of intermediate chains of amylopectin. Furthermore, OsbZIP58 was shown to bind directly to the promoters of six starch-synthesizing genes, OsAGPL3, Wx, OsSSIIa, SBE1, OsBEIIb, and ISA2, and to regulate their expression. These findings indicate that OsbZIP58 functions as a key regulator of starch synthesis in rice seeds and provide new insights into seed quality control.
The zinc transporter ZIP12 regulates the pulmonary vascular response to chronic hypoxia.
Zhao, Lan; Oliver, Eduardo; Maratou, Klio; Atanur, Santosh S; Dubois, Olivier D; Cotroneo, Emanuele; Chen, Chien-Nien; Wang, Lei; Arce, Cristina; Chabosseau, Pauline L; Ponsa-Cobas, Joan; Frid, Maria G; Moyon, Benjamin; Webster, Zoe; Aldashev, Almaz; Ferrer, Jorge; Rutter, Guy A; Stenmark, Kurt R; Aitman, Timothy J; Wilkins, Martin R
2015-08-20
The typical response of the adult mammalian pulmonary circulation to a low oxygen environment is vasoconstriction and structural remodelling of pulmonary arterioles, leading to chronic elevation of pulmonary artery pressure (pulmonary hypertension) and right ventricular hypertrophy. Some mammals, however, exhibit genetic resistance to hypoxia-induced pulmonary hypertension. We used a congenic breeding program and comparative genomics to exploit this variation in the rat and identified the gene Slc39a12 as a major regulator of hypoxia-induced pulmonary vascular remodelling. Slc39a12 encodes the zinc transporter ZIP12. Here we report that ZIP12 expression is increased in many cell types, including endothelial, smooth muscle and interstitial cells, in the remodelled pulmonary arterioles of rats, cows and humans susceptible to hypoxia-induced pulmonary hypertension. We show that ZIP12 expression in pulmonary vascular smooth muscle cells is hypoxia dependent and that targeted inhibition of ZIP12 inhibits the rise in intracellular labile zinc in hypoxia-exposed pulmonary vascular smooth muscle cells and their proliferation in culture. We demonstrate that genetic disruption of ZIP12 expression attenuates the development of pulmonary hypertension in rats housed in a hypoxic atmosphere. This new and unexpected insight into the fundamental role of a zinc transporter in mammalian pulmonary vascular homeostasis suggests a new drug target for the pharmacological management of pulmonary hypertension.
Disease Human - MDC_CardiovascularMortality2006
NSGIC Local Govt | GIS Inventory — Polygon feature class based on Zip Code boundaries showing the rate of deaths due to major cardiovascular diseases per 1000 residents of Miami-Dade County in 2006.
Disease Human - MDC_LowBirthWeight
NSGIC Local Govt | GIS Inventory — Polygon feature class based on Zip Code boundaries showing the percentage of babies born in Miami-Dade County in 2006 with low birth weights. Low birth weight is...
Disease Human - MDC_CLRDMortality2006
NSGIC Local Govt | GIS Inventory — Polygon feature class based on Zip Code boundaries showing the rate of deaths per 100,000 residents due to Chronic Lower Respiratory Disease (CLRD) in Miami-Dade...
Illness Human - MDC_InfantMortality2006
NSGIC Local Govt | GIS Inventory — Polygon feature class based on Zip Code boundaries showing the rate of infant mortality per 1000 births in Miami-Dade County, 2006. Rate does not include out of...
A QUALITY ASSESSMENT METHOD FOR 3D ROAD POLYGON OBJECTS
Directory of Open Access Journals (Sweden)
L. Gao
2015-08-01
Full Text Available With the development of the economy, the fast and accurate extraction of the city road is significant for GIS data collection and update, remote sensing images interpretation, mapping and spatial database updating etc. 3D GIS has attracted more and more attentions from academics, industries and governments with the increase of requirements for interoperability and integration of different sources of data. The quality of 3D geographic objects is very important for spatial analysis and decision-making. This paper presents a method for the quality assessment of the 3D road polygon objects which is created by integrating 2D Road Polygon data with LiDAR point cloud and other height information such as Spot Height data in Hong Kong Island. The quality of the created 3D road polygon data set is evaluated by the vertical accuracy, geometric and attribute accuracy, connectivity error, undulation error and completeness error and the final results are presented.
Long-term repetition priming with symmetrical polygons and words.
Kersteen-Tucker, Z
1991-01-01
In two different tasks, subjects were asked to make lexical decisions (word or nonword) and symmetry judgments (symmetrical or nonsymmetrical) about two-dimensional polygons. In both tasks, every stimulus was repeated at one of four lags (0, 1, 4, or 8 items interposed between the first and second stimulus presentations). This paradigm, known as repetition priming, revealed comparable short-term priming (Lag 0) and long-term priming (Lags 1, 4, and 8) both for symmetrical polygons and for words. A shorter term component (Lags 0 and 1) of priming was observed for nonwords, and only very short-term priming (Lag 0) was observed for nonsymmetrical polygons. These results indicate that response facilitation accruing from repeated exposure can be observed for stimuli that have no preexisting memory representations and suggest that perceptual factors contribute to repetition-priming effects.
A modified detector concept for SuperCDMS: The HiZIP and its charge performance
Energy Technology Data Exchange (ETDEWEB)
Page, Kedar Mohan [Queen' s U.
2013-01-01
SuperCDMS (Super Cryogenic Dark Matter Search) is a leading direct dark mat-ter search experiment which uses solid state detectors (Ge crystals) at milliKelvintemperatures to look for nuclear recoils caused by dark matter interactions in the de-tector. `Weakly Interacting Massive Particles' (WIMPs) are the most favoured darkmatter candidate particles. SuperCDMS, like many other direct dark matter searchexperiments, primarily looks for WIMPs. The measurement of both the ionizationand the lattice vibration (phonon) signals from an interaction in the detector allow itto discriminate against electron recoils which are the main source of background forWIMP detection.SuperCDMS currently operates about 9 kg of Ge detectors at the Soudan under-ground lab in northern Minnesota. In its next phase, SuperCDMS SNOLAB plansto use 100-200 kg of target mass (Ge) which would allow it to probe more of theinteresting and and as of yet unexplored parameter space for WIMPs predicted bytheoretical models. The SuperCDMS Queen's Test Facility is a detector test facilitywhich is intended to serve as detector testing and detector research and developmentpurposes for the SuperCDMS experiment.A modifed detector called the HiZIP (Half-iZIP), which is reduced in complex-ity in comparison to the currently used iZIP (interleaved Z-sensitive Ionization and Phonon mediated) detectors, is studied in this thesis. The HiZIP detector designalso serves to discriminate against background from multiple scatter events occurringclose to the surfaces in a single detector. Studies carried out to compare the surfaceevent leakage in the HiZIP detector using limited information from iZIP data takenat SuperCDMS test facility at UC Berkley produce a highly conservative upper limitof 5 out of 10,000 events at 90% condence level. This upper limit is the best amongmany different HiZIP congurations that were investigated and is comparable to theupper limit calculated for an HiZIP detector in the same way
Salt and drought stress and ABA responses related to bZIP genes from V. radiata and V. angularis.
Wang, Lanfen; Zhu, Jifeng; Li, Xiaoming; Wang, Shumin; Wu, Jing
2018-04-20
Mung bean and adzuki bean are warm-season legumes widely cultivated in China. However, bean production in major producing regions is limited by biotic and abiotic stress, such as drought and salt stress. Basic leucine zipper (bZIP) genes play key roles in responses to various biotic and abiotic stresses. However, only several bZIP genes involved in drought and salt stress in legumes, especially Vigna radiata and Vigna angularis, have been identified. In this study, we identified 54 and 50 bZIP proteins from whole-genome sequences of V. radiata and V. angularis, respectively. First, we comprehensively surveyed the characteristics of all bZIP genes, including their gene structure, chromosome distribution and motif composition. Phylogenetic trees showed that VrbZIP and VabZIP proteins were divided into ten clades comprising nine known and one unknown subgroup. The results of the nucleotide substitution rate of the orthologous gene pairs showed that bZIP proteins have undergone strong purifying selection: V. radiata and V. angularis diverged 1.25 million years ago (mya) to 9.20 mya (average of 4.95 mya). We also found that many cis-acting regulatory elements (CAREs) involved in abiotic stress and plant hormone responses were detected in the putative promoter regions of the bZIP genes. Finally, using the quantitative real-time PCR (qRT-PCR) method, we performed expression profiling of the bZIP genes in response to drought, salt and abscisic acid (ABA). We identified several bZIP genes that may be involved in drought and salt responses. Generally, our results provided useful and rich resources of VrbZIP and VabZIP genes for the functional characterization and understanding of bZIP transcription factors (TFs) in warm-season legumes. In addition, our results revealed important and interesting data - a subset of VrbZIP and VabZIP gene expression profiles in response to drought, salt and ABA stress. These results provide gene expression evidence for the selection of
Agency for Toxic Substances and Disease Registry (ATSDR) Hazardous Waste Site Polygon Data, 1996
National Aeronautics and Space Administration — The Agency for Toxic Substances and Disease Registry (ATSDR) Hazardous Waste Site Polygon Data, 1996 consists of 2042 polygons for selected hazardous waste sites...
United States National Grid for New Mexico, UTM 12, (1000m X 1000m polygons )
Earth Data Analysis Center, University of New Mexico — This is a polygon feature data layer of United States National Grid (1000m x 1000m polygons ) constructed by the Center for Interdisciplinary Geospatial Information...
United States National Grid for New Mexico, UTM 13, (1000m X 1000m polygons )
Earth Data Analysis Center, University of New Mexico — This is a polygon feature data layer of United States National Grid (1000m x 1000m polygons ) constructed by the Center for Interdisciplinary Geospatial Information...
A fast direct sampling algorithm for equilateral closed polygons
International Nuclear Information System (INIS)
Cantarella, Jason; Duplantier, Bertrand; Shonkwiler, Clayton; Uehara, Erica
2016-01-01
Sampling equilateral closed polygons is of interest in the statistical study of ring polymers. Over the past 30 years, previous authors have proposed a variety of simple Markov chain algorithms (but have not been able to show that they converge to the correct probability distribution) and complicated direct samplers (which require extended-precision arithmetic to evaluate numerically unstable polynomials). We present a simple direct sampler which is fast and numerically stable, and analyze its runtime using a new formula for the volume of equilateral polygon space as a Dirichlet-type integral. (paper)
Polygons of global undersea features for geographic searches
Hartwell, Stephen R.; Wingfield, Dana K.; Allwardt, Alan O.; Lightsom, Frances L.; Wong, Florence L.
2018-01-01
A shapefile of 311 undersea features from all major oceans and seas has been created as an aid for retrieving georeferenced information resources. Geospatial information systems with the capability to search user-defined, polygonal geographic areas will be able to utilize this shapefile or secondary products derived from it, such as linked data based on well-known text representations of the individual polygons within the shapefile. Version 1.1 of this report also includes a linked data representation of 299 of these features and their spatial extents.
Calculus domains modelled using an original bool algebra based on polygons
Oanta, E.; Panait, C.; Raicu, A.; Barhalescu, M.; Axinte, T.
2016-08-01
Analytical and numerical computer based models require analytical definitions of the calculus domains. The paper presents a method to model a calculus domain based on a bool algebra which uses solid and hollow polygons. The general calculus relations of the geometrical characteristics that are widely used in mechanical engineering are tested using several shapes of the calculus domain in order to draw conclusions regarding the most effective methods to discretize the domain. The paper also tests the results of several CAD commercial software applications which are able to compute the geometrical characteristics, being drawn interesting conclusions. The tests were also targeting the accuracy of the results vs. the number of nodes on the curved boundary of the cross section. The study required the development of an original software consisting of more than 1700 computer code lines. In comparison with other calculus methods, the discretization using convex polygons is a simpler approach. Moreover, this method doesn't lead to large numbers as the spline approximation did, in that case being required special software packages in order to offer multiple, arbitrary precision. The knowledge resulted from this study may be used to develop complex computer based models in engineering.
Small Scale Polygons and the History of Ground Ice on Mars
Mellon, Michael T.
2003-01-01
Recent progress on polygon modeling has focused on the diameter and surface relief that we expect of thermal-contraction polygons in martian permafrost. With this in mind, we developed a finite-element model of thermal-contraction-crack behavior in permafrost in a martian climate. This model was generated from a finite element code by Jay Melosh (called TECTON) originally developed for terrestrial and planetary crustal-deformation studies. We adapted this model to martian permafrost by including time (and temperature) dependent rheologies, boundary conditions, and isotropic thermal-contraction, as well as several small adaptations to a martian environment. We tested our model extensively, including comparison to an analytic solution of pre-fracture stress. We recently published an analysis of two potential sources of water for forming the recent gullies. In this work we first evaluated the potential for near-surface ground ice (in the top meter or so of soil) to melt under conditions of solar heating on sloped surfaces at high obliquity, utilizing both thermal and diffusion-based ground-ice-stability models; our results suggested that the ground ice will sublimate, and the ice table will recede to greater depths before the melting temperature can be reached. An exception can occur only for extremely salt-rich ice, depressing the freezing point.
Decomposition of orthogonal polygons in a set of rectanglеs
Shestakov, E.; Voronov, A.
2009-01-01
Algorithm for covering orthogonal integrated circuit layout objects is considered. Objects of the research are special single-connected orthogonal polygons which are generated during decomposition of any multiply connected polygon in a set of single-connected orthogonal polygons. Developed algorithm for covering polygons based on the mathematical techinque of logic matrix transformation. Results described in this paper, can be applied in computer geometry and image analysis.
A simple algorithm for computing positively weighted straight skeletons of monotone polygons.
Biedl, Therese; Held, Martin; Huber, Stefan; Kaaser, Dominik; Palfrader, Peter
2015-02-01
We study the characteristics of straight skeletons of monotone polygonal chains and use them to devise an algorithm for computing positively weighted straight skeletons of monotone polygons. Our algorithm runs in [Formula: see text] time and [Formula: see text] space, where n denotes the number of vertices of the polygon.
Speetjens, M.F.M.; Meleshko, V.V.; Heijst, van G.J.F.
2014-01-01
The present study addresses the classical problem of the dynamics and stability of a cluster of N point vortices of equal strength arranged in a polygonal configuration ("N-vortex polygons"). In unbounded domains, such N-vortex polygons are unconditionally stable for N
International Nuclear Information System (INIS)
Chenal, C.
1996-01-01
Semipalatinsk in Kazakhstan was one of the nuclear weapons polygon for atmospheric, excavation and underground tests. After a description of the actual state of the polygon, a dosimetric approach inside and outside the polygon is presented from 1949 to 1989. (A.B.). 5 refs., 3 figs., 5 tabs
Zhou, Yan; Xu, Daixiang; Jia, Ledong; Huang, Xiaohu; Ma, Guoqiang; Wang, Shuxian; Zhu, Meichen; Zhang, Aoxiang; Guan, Mingwei; Lu, Kun; Xu, Xinfu; Wang, Rui; Li, Jiana; Qu, Cunmin
2017-10-24
The basic region/leucine zipper motif (bZIP) transcription factor family is one of the largest families of transcriptional regulators in plants. bZIP genes have been systematically characterized in some plants, but not in rapeseed ( Brassica napus ). In this study, we identified 247 BnbZIP genes in the rapeseed genome, which we classified into 10 subfamilies based on phylogenetic analysis of their deduced protein sequences. The BnbZIP genes were grouped into functional clades with Arabidopsis genes with similar putative functions, indicating functional conservation. Genome mapping analysis revealed that the BnbZIPs are distributed unevenly across all 19 chromosomes, and that some of these genes arose through whole-genome duplication and dispersed duplication events. All expression profiles of 247 bZIP genes were extracted from RNA-sequencing data obtained from 17 different B . napus ZS11 tissues with 42 various developmental stages. These genes exhibited different expression patterns in various tissues, revealing that these genes are differentially regulated. Our results provide a valuable foundation for functional dissection of the different BnbZIP homologs in B . napus and its parental lines and for molecular breeding studies of bZIP genes in B . napus .
Zhang, C H; Ma, R J; Shen, Z J; Sun, X; Korir, N K; Yu, M L
2014-04-08
In this study, 33 homeodomain-leucine zipper (HD-ZIP) genes were identified in peach using the HD-ZIP amino acid sequences of Arabidopsis thaliana as a probe. Based on the phylogenetic analysis and the individual gene or protein characteristics, the HD-ZIP gene family in peach can be classified into 4 subfamilies, HD-ZIP I, II, III, and IV, containing 14, 7, 4, and 8 members, respectively. The most closely related peach HD-ZIP members within the same subfamilies shared very similar gene structure in terms of either intron/exon numbers or lengths. Almost all members of the same subfamily shared common motif compositions, thereby implying that the HD-ZIP proteins within the same subfamily may have functional similarity. The 33 peach HD-ZIP genes were distributed across scaffolds 1 to 7. Although the primary structure varied among HD-ZIP family proteins, their tertiary structures were similar. The results from this study will be useful in selecting candidate genes from specific subfamilies for functional analysis.
A modified detector concept for SuperCDMS: The HiZIP and its charge performance
Page, Kedar Mohan
SuperCDMS is a leading direct dark matter search experiment which uses solid state detectors (Ge crystals) at milliKelvin temperatures to look for nuclear recoils caused by dark matter interactions in the detector. 'Weakly Interacting Massive Particles' (WIMPs) are the most favoured dark matter candidate particles. SuperCDMS, like many other direct dark matter search experiments, primarily looks for WIMPs. The measurement of both the ionization and the lattice vibration (phonon) signals from an interaction in the detector allow it to discriminate against electron recoils which are the main source of background for WIMP detection. SuperCDMS currently operates about 9 kgs worth of germanium detectors at the Soudan underground lab in northern Minnesota. In its next phase, SuperCDMS SNOLAB, it plans to use 100-200 kg of target mass (Ge) which would allow it to probe more of the interesting and unexplored parameter space for WIMPs predicted by theoretical models. The SuperCDMS Queen's Test Facility is a detector testing facility which is intended to serve detector testing and detector research and development purposes for the SuperCDMS experiment. A modified detector called the 'HiZIP' (Half-iZIP), which is reduced in complexity in comparison to the currently used iZIP (interleaved Z-sensitive Ionization and Phonon mediated) detectors, is studied in this thesis. The HiZIP detector design also serves to discriminate against background from multiple scatter events occurring close to the surfaces in a single detector. Studies carried out to compare the surface event leakage in the HiZIP detector using limited information from iZIP data taken at SuperCDMS test facility at UC Berkley produce a highly conservative upper limit of 5 out of 10,000 events at 90% confidence level. This upper limit is the best among many different HiZIP configurations that were investigated and is comparable to the upper limit calculated for an iZIP detector in the same way using the same data. A
Directory of Open Access Journals (Sweden)
Karen Voelkel-Meiman
2015-06-01
Full Text Available Accurate chromosome segregation during meiosis relies on the presence of crossover events distributed among all chromosomes. MutSγ and MutLγ homologs (Msh4/5 and Mlh1/3 facilitate the formation of a prominent group of meiotic crossovers that mature within the context of an elaborate chromosomal structure called the synaptonemal complex (SC. SC proteins are required for intermediate steps in the formation of MutSγ-MutLγ crossovers, but whether the assembled SC structure per se is required for MutSγ-MutLγ-dependent crossover recombination events is unknown. Here we describe an interspecies complementation experiment that reveals that the mature SC is dispensable for the formation of Mlh3-dependent crossovers in budding yeast. Zip1 forms a major structural component of the budding yeast SC, and is also required for MutSγ and MutLγ-dependent crossover formation. Kluyveromyces lactis ZIP1 expressed in place of Saccharomyces cerevisiae ZIP1 in S. cerevisiae cells fails to support SC assembly (synapsis but promotes wild-type crossover levels in those nuclei that progress to form spores. While stable, full-length SC does not assemble in S. cerevisiae cells expressing K. lactis ZIP1, aggregates of K. lactis Zip1 displayed by S. cerevisiae meiotic nuclei are decorated with SC-associated proteins, and K. lactis Zip1 promotes the SUMOylation of the SC central element protein Ecm11, suggesting that K. lactis Zip1 functionally interfaces with components of the S. cerevisiae synapsis machinery. Moreover, K. lactis Zip1-mediated crossovers rely on S. cerevisiae synapsis initiation proteins Zip3, Zip4, Spo16, as well as the Mlh3 protein, as do the crossovers mediated by S. cerevisiae Zip1. Surprisingly, however, K. lactis Zip1-mediated crossovers are largely Msh4/Msh5 (MutSγ-independent. This separation-of-function version of Zip1 thus reveals that neither assembled SC nor MutSγ is required for Mlh3-dependent crossover formation per se in budding yeast
PolyFit: Polygonal Surface Reconstruction from Point Clouds
Nan, Liangliang; Wonka, Peter
2017-01-01
We propose a novel framework for reconstructing lightweight polygonal surfaces from point clouds. Unlike traditional methods that focus on either extracting good geometric primitives or obtaining proper arrangements of primitives, the emphasis of this work lies in intersecting the primitives (planes only) and seeking for an appropriate combination of them to obtain a manifold polygonal surface model without boundary.,We show that reconstruction from point clouds can be cast as a binary labeling problem. Our method is based on a hypothesizing and selection strategy. We first generate a reasonably large set of face candidates by intersecting the extracted planar primitives. Then an optimal subset of the candidate faces is selected through optimization. Our optimization is based on a binary linear programming formulation under hard constraints that enforce the final polygonal surface model to be manifold and watertight. Experiments on point clouds from various sources demonstrate that our method can generate lightweight polygonal surface models of arbitrary piecewise planar objects. Besides, our method is capable of recovering sharp features and is robust to noise, outliers, and missing data.
Determination of wave direction from linear and polygonal arrays
Digital Repository Service at National Institute of Oceanography (India)
Fernandes, A.A; Gouveia, A; Nagarajan, R.
documentation of Borgman (1974) in case of linear arrays; and the second issue being the failure of Esteva (1976, 1977) to correctly determine wave directions over the design range 25 to 7 sec of his polygonal array. This paper presents requisite documentation...
Vibrational resonances of nonrigid vehicles: Polygonization and ripple patterns
Dekker, H.
2009-01-01
The well-known phenomenon of ripples on roads has its modern counterpart in ripple patterns on railroads and polygonization of wheels on state-of-the-art lightrail streetcars. Here we study an idealized mechanical suspension model for the vibrational frequency response of a buggy with a nonrigid
design chart procedures for polygonal concrete-filled steel columns
African Journals Online (AJOL)
ADMIN
hexagonal and octagonal steel-concrete composite columns subjected to ... This paper also outlines procedures that will enable preparation of ... buildings and in a variety of large-span building ... Likewise, hot-rolled steel tubes are used while ... small moderate large. Fig. 2. Possible arrangement of composite polygonal ...
A Teaching Polygon Makes Learning a Community Enterprise
Colgan, Mark; DeLong, Matt
2015-01-01
In order to strengthen departmental collegiality and improve teaching, our mathematics department instituted a Teaching Polygon. Building on the faculty development idea of Teaching Squares, each member of our department visited one class taught by every other department member in a round-robin fashion during the school year. The visits were…
Sub-wavelength resonances in polygonal metamaterial cylinders
DEFF Research Database (Denmark)
Arslanagic, Samel; Breinbjerg, Olav
2008-01-01
It has been shown that the sub-wavelength resonances of circular MTM cylinders also occur for polygonal MTM cylinders. This is the case for lossless and non-dispersive cylinders as well as lossy and dispersive cylinders. The sub-wavelength resonances are thus not limited to structures of canonical...
Polygons, Pillars and Pavilions: Discovering Connections between Geometry and Architecture
Madden, Sean Patrick
2017-01-01
Crowning the second semester of geometry, taught within a Catholic middle school, the author's students explored connections between the geometry of regular polygons and architecture of local buildings. They went on to explore how these principles apply famous buildings around the world such as the monuments of Washington, D.C. and the elliptical…
Computing the Fréchet distance between folded polygons
Cook IV, A.F.; Driemel, A.; Sherette, J.; Wenk, C.
2015-01-01
Computing the Fréchet distance for surfaces is a surprisingly hard problem and the only known polynomial-time algorithm is limited to computing it between flat surfaces. We study the problem of computing the Fréchet distance for a class of non-flat surfaces called folded polygons. We present a
PolyFit: Polygonal Surface Reconstruction from Point Clouds
Nan, Liangliang
2017-12-25
We propose a novel framework for reconstructing lightweight polygonal surfaces from point clouds. Unlike traditional methods that focus on either extracting good geometric primitives or obtaining proper arrangements of primitives, the emphasis of this work lies in intersecting the primitives (planes only) and seeking for an appropriate combination of them to obtain a manifold polygonal surface model without boundary.,We show that reconstruction from point clouds can be cast as a binary labeling problem. Our method is based on a hypothesizing and selection strategy. We first generate a reasonably large set of face candidates by intersecting the extracted planar primitives. Then an optimal subset of the candidate faces is selected through optimization. Our optimization is based on a binary linear programming formulation under hard constraints that enforce the final polygonal surface model to be manifold and watertight. Experiments on point clouds from various sources demonstrate that our method can generate lightweight polygonal surface models of arbitrary piecewise planar objects. Besides, our method is capable of recovering sharp features and is robust to noise, outliers, and missing data.
Potential novel bZIP-like gene for resistance to Erysiphe necator ...
African Journals Online (AJOL)
AJL
2012-06-19
Jun 19, 2012 ... In this study, a novel bZIP-like gene was isolated from Chinese wild Vitis ... Results reveal that it was in lower lever in flower than in leaf, stem, tendril and fruit. .... First-strand cDNA was synthesized from 1 µg of DNase treated.
The prion-ZIP connection: From cousins to partners in iron uptake
Singh, Neena; Asthana, Abhishek; Baksi, Shounak; Desai, Vilok; Haldar, Swati; Hari, Sahi; Tripathi, Ajai K
2015-01-01
ABSTRACT Converging observations from disparate lines of inquiry are beginning to clarify the cause of brain iron dyshomeostasis in sporadic Creutzfeldt-Jakob disease (sCJD), a neurodegenerative condition associated with the conversion of prion protein (PrPC), a plasma membrane glycoprotein, from α-helical to a β-sheet rich PrP-scrapie (PrPSc) isoform. Biochemical evidence indicates that PrPC facilitates cellular iron uptake by functioning as a membrane-bound ferrireductase (FR), an activity necessary for the transport of iron across biological membranes through metal transporters. An entirely different experimental approach reveals an evolutionary link between PrPC and the Zrt, Irt-like protein (ZIP) family, a group of proteins involved in the transport of zinc, iron, and manganese across the plasma membrane. Close physical proximity of PrPC with certain members of the ZIP family on the plasma membrane and increased uptake of extracellular iron by cells that co-express PrPC and ZIP14 suggest that PrPC functions as a FR partner for certain members of this family. The connection between PrPC and ZIP proteins therefore extends beyond common ancestry to that of functional cooperation. Here, we summarize evidence supporting the facilitative role of PrPC in cellular iron uptake, and implications of this activity on iron metabolism in sCJD brains. PMID:26689487
Modeling of chromosome intermingling by partially overlapping uniform random polygons.
Blackstone, T; Scharein, R; Borgo, B; Varela, R; Diao, Y; Arsuaga, J
2011-03-01
During the early phase of the cell cycle the eukaryotic genome is organized into chromosome territories. The geometry of the interface between any two chromosomes remains a matter of debate and may have important functional consequences. The Interchromosomal Network model (introduced by Branco and Pombo) proposes that territories intermingle along their periphery. In order to partially quantify this concept we here investigate the probability that two chromosomes form an unsplittable link. We use the uniform random polygon as a crude model for chromosome territories and we model the interchromosomal network as the common spatial region of two overlapping uniform random polygons. This simple model allows us to derive some rigorous mathematical results as well as to perform computer simulations easily. We find that the probability that one uniform random polygon of length n that partially overlaps a fixed polygon is bounded below by 1 − O(1/√n). We use numerical simulations to estimate the dependence of the linking probability of two uniform random polygons (of lengths n and m, respectively) on the amount of overlapping. The degree of overlapping is parametrized by a parameter [Formula: see text] such that [Formula: see text] indicates no overlapping and [Formula: see text] indicates total overlapping. We propose that this dependence relation may be modeled as f (ε, m, n) = [Formula: see text]. Numerical evidence shows that this model works well when [Formula: see text] is relatively large (ε ≥ 0.5). We then use these results to model the data published by Branco and Pombo and observe that for the amount of overlapping observed experimentally the URPs have a non-zero probability of forming an unsplittable link.
Theory on the Mechanism of DNA Renaturation: Stochastic Nucleation and Zipping.
Directory of Open Access Journals (Sweden)
Gnanapragasam Niranjani
Full Text Available Renaturation of the complementary single strands of DNA is one of the important processes that requires better understanding in the view of molecular biology and biological physics. Here we develop a stochastic dynamical model on the DNA renaturation. According to our model there are at least three steps in the renaturation process viz. nonspecific-contact formation, correct-contact formation and nucleation, and zipping. Most of the earlier two-state models combined nucleation with nonspecific-contact formation step. In our model we suggest that it is considerably meaningful when we combine the nucleation with the zipping since nucleation is the initial step of zipping and nucleated and zipping molecules are indistinguishable. Nonspecific contact formation step is a pure three-dimensional diffusion controlled collision process. Whereas nucleation involves several rounds of one-dimensional slithering and internal displacement dynamics of one single strand of DNA on the other complementary strand in the process of searching for the correct-contact and then initiate nucleation. Upon nucleation, the stochastic zipping follows to generate a fully renatured double stranded DNA. It seems that the square-root dependency of the overall renaturation rate constant on the length of reacting single strands originates mainly from the geometric constraints in the diffusion controlled nonspecific-contact formation step. Further the inverse scaling of the renaturation rate on the viscosity of reaction medium also originates from nonspecific contact formation step. On the other hand the inverse scaling of the renaturation rate with the sequence complexity originates from the stochastic zipping which involves several rounds of crossing over the free-energy barrier at microscopic levels. When the sequence of renaturing single strands of DNA is repetitive with less complexity then the cooperative effects will not be noticeable since the parallel zipping will be a
Energy Technology Data Exchange (ETDEWEB)
Kim, Chan Hyeong; Jeong, Jong Hwi [Department of Nuclear Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Bolch, Wesley E [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL 32611 (United States); Cho, Kun-Woo [Korea Institute of Nuclear Safety, 19 Guseong-dong, Yuseong-gu, Daejeon 305-600 (Korea, Republic of); Hwang, Sung Bae, E-mail: chkim@hanyang.ac.kr [Department of Physical Therapy, Kyungbuk College, Hyucheon 2-dong, Yeongju-si, Gyeongbuk 750-712 (Korea, Republic of)
2011-05-21
Even though the hybrid phantom embodies both the anatomic reality of voxel phantoms and the deformability of stylized phantoms, it must be voxelized to be used in a Monte Carlo code for dose calculation or some imaging simulation, which incurs the inherent limitations of voxel phantoms. In the present study, a voxel phantom named VKH-Man (Visible Korean Human-Man), was converted to a polygon-surface phantom (PSRK-Man, Polygon-Surface Reference Korean-Man), which was then adjusted to the Reference Korean data. Subsequently, the PSRK-Man polygon phantom was directly, without any voxelization process, implemented in the Geant4 Monte Carlo code for dose calculations. The calculated dose values and computation time were then compared with those of HDRK-Man (High Definition Reference Korean-Man), a corresponding voxel phantom adjusted to the same Reference Korean data from the same VKH-Man voxel phantom. Our results showed that the calculated dose values of the PSRK-Man surface phantom agreed well with those of the HDRK-Man voxel phantom. The calculation speed for the PSRK-Man polygon phantom though was 70-150 times slower than that of the HDRK-Man voxel phantom; that speed, however, could be acceptable in some applications, in that direct use of the surface phantom PSRK-Man in Geant4 does not require a separate voxelization process. Computing speed can be enhanced, in future, either by optimizing the Monte Carlo transport kernel for the polygon surfaces or by using modern computing technologies such as grid computing and general-purpose computing on graphics processing units programming.
International Nuclear Information System (INIS)
Kim, Chan Hyeong; Jeong, Jong Hwi; Bolch, Wesley E; Cho, Kun-Woo; Hwang, Sung Bae
2011-01-01
Even though the hybrid phantom embodies both the anatomic reality of voxel phantoms and the deformability of stylized phantoms, it must be voxelized to be used in a Monte Carlo code for dose calculation or some imaging simulation, which incurs the inherent limitations of voxel phantoms. In the present study, a voxel phantom named VKH-Man (Visible Korean Human-Man), was converted to a polygon-surface phantom (PSRK-Man, Polygon-Surface Reference Korean-Man), which was then adjusted to the Reference Korean data. Subsequently, the PSRK-Man polygon phantom was directly, without any voxelization process, implemented in the Geant4 Monte Carlo code for dose calculations. The calculated dose values and computation time were then compared with those of HDRK-Man (High Definition Reference Korean-Man), a corresponding voxel phantom adjusted to the same Reference Korean data from the same VKH-Man voxel phantom. Our results showed that the calculated dose values of the PSRK-Man surface phantom agreed well with those of the HDRK-Man voxel phantom. The calculation speed for the PSRK-Man polygon phantom though was 70-150 times slower than that of the HDRK-Man voxel phantom; that speed, however, could be acceptable in some applications, in that direct use of the surface phantom PSRK-Man in Geant4 does not require a separate voxelization process. Computing speed can be enhanced, in future, either by optimizing the Monte Carlo transport kernel for the polygon surfaces or by using modern computing technologies such as grid computing and general-purpose computing on graphics processing units programming.
Levitan, David; Fortis-Santiago, Yaihara; Figueroa, Joshua A; Reid, Emily E; Yoshida, Takashi; Barry, Nicholas C; Russo, Abigail; Katz, Donald B
2016-10-12
In neuroscientists' attempts to understand the long-term storage of memory, topics of particular importance and interest are the cellular and system mechanisms of maintenance (e.g., those sensitive to ζ-inhibitory peptide, ZIP) and those induced by memory retrieval (i.e., reconsolidation). Much is known about each of these processes in isolation, but less is known concerning how they interact. It is known that ZIP sensitivity and memory retrieval share at least some molecular targets (e.g., recycling α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, AMPA, receptors to the plasma membrane); conversely, the fact that sensitivity to ZIP emerges only after consolidation ends suggests that consolidation (and by extension reconsolidation) and maintenance might be mutually exclusive processes, the onset of one canceling the other. Here, we use conditioned taste aversion (CTA) in rats, a cortically dependent learning paradigm, to test this hypothesis. First, we demonstrate that ZIP infusions into gustatory cortex begin interfering with CTA memory 43-45 h after memory acquisition-after consolidation ends. Next, we show that a retrieval trial administered after this time point interrupts the ability of ZIP to induce amnesia and that ZIP's ability to induce amnesia is reengaged only 45 h after retrieval. This pattern of results suggests that memory retrieval and ZIP-sensitive maintenance mechanisms are mutually exclusive and that the progression from one to the other are similar after acquisition and retrieval. They also reveal concrete differences between ZIP-sensitive mechanisms induced by acquisition and retrieval: the latency with which ZIP-sensitive mechanisms are expressed differ for the two processes. Memory retrieval and the molecular mechanisms that are sensitive to ζ-inhibitory peptide (ZIP) are the few manipulations that have been shown to effect memory maintenance. Although much is known about their effect on maintenance separately, it is unknown how they
Li, Dayong; Fu, Fuyou; Zhang, Huijuan; Song, Fengming
2015-10-12
Transcription factors of the basic leucine zipper (bZIP) family represent exclusively in eukaryotes and have been shown to regulate diverse biological processes in plant growth and development as well as in abiotic and biotic stress responses. However, little is known about the bZIP family in tomato (Solanum lycopersicum L.). The SlbZIP genes were identified using local BLAST and hidden Markov model profile searches. The phylogenetic trees, conserved motifs and gene structures were generated by MEGA6.06, MEME tool and gene Structure Display Server, respectively. The syntenic block diagrams were generated by the Circos software. The transcriptional gene expression profiles were obtained using Genevestigator tool and quantitative RT-PCR. In the present study, we carried out a genome-wide identification and systematic analyses of 69 SlbZIP genes that distributes unevenly on the tomato chromosomes. This family can be divided into 9 groups according to the phylogenetic relationship among the SlbZIP proteins. Six kinds of intron patterns (a-f) within the basic and hinge regions are defined. The additional conserved motifs and their presence of the group specificity were also identified. Further, we predicted the DNA-binding patterns and the dimerization property on the basis of the characteristic features in the basic and hinge regions and the leucine zipper, respectively, which supports our classification greatly and helps to classify 24 distinct subfamilies. Within the SlbZIP family, a total of 40 SlbZIP genes are located in the segmental duplicate regions in the tomato genome, suggesting that the segment chromosomal duplications contribute greatly to the expansion of the tomato SlbZIP family. Expression profiling analyses of 59 SlbZIP genes using quantitative RT-PCR and publicly available microarray data indicate that the tomato SlbZIP genes have distinct and diverse expression patterns in different tissues and developmental stages and many of the tomato bZIP genes
Abscisic-acid-dependent basic leucine zipper (bZIP) transcription factors in plant abiotic stress.
Banerjee, Aditya; Roychoudhury, Aryadeep
2017-01-01
One of the major causes of significant crop loss throughout the world is the myriad of environmental stresses including drought, salinity, cold, heavy metal toxicity, and ultraviolet-B (UV-B) rays. Plants as sessile organisms have evolved various effective mechanism which enable them to withstand this plethora of stresses. Most of such regulatory mechanisms usually follow the abscisic-acid (ABA)-dependent pathway. In this review, we have primarily focussed on the basic leucine zipper (bZIP) transcription factors (TFs) activated by the ABA-mediated signalosome. Upon perception of ABA by specialized receptors, the signal is transduced via various groups of Ser/Thr kinases, which phosphorylate the bZIP TFs. Following such post-translational modification of TFs, they are activated so that they bind to specific cis-acting sequences called abscisic-acid-responsive elements (ABREs) or GC-rich coupling elements (CE), thereby influencing the expression of their target downstream genes. Several in silico techniques have been adopted so far to predict the structural features, recognize the regulatory modification sites, undergo phylogenetic analyses, and facilitate genome-wide survey of TF under multiple stresses. Current investigations on the epigenetic regulation that controls greater accessibility of the inducible regions of DNA of the target gene to the bZIP TFs exclusively under stress situations, along with the evolved stress memory responses via genomic imprinting mechanism, have been highlighted. The potentiality of overexpression of bZIP TFs, either in a homologous or in a heterologous background, in generating transgenic plants tolerant to various abiotic stressors have also been addressed by various groups. The present review will provide a coherent documentation on the functional characterization and regulation of bZIP TFs under multiple environmental stresses, with the major goal of generating multiple-stress-tolerant plant cultivars in near future.
ZmbZIP60 mRNA is spliced in maize in response to ER stress
Directory of Open Access Journals (Sweden)
Li Yanjie
2012-03-01
Full Text Available Abstract Background Adverse environmental conditions produce ER stress and elicit the unfolded protein response (UPR in plants. Plants are reported to have two "arms" of the ER stress signaling pathway-one arm involving membrane-bound transcription factors and the other involving a membrane-associated RNA splicing factor, IRE1. IRE1 in yeast to mammals recognizes a conserved twin loop structure in the target RNA. Results A segment of the mRNA encoding ZmbZIP60 in maize can be folded into a twin loop structure, and in response to ER stress this mRNA is spliced, excising a 20b intron. Splicing converts the predicted protein from a membrane-associated transcription factor to one that is targeted to the nucleus. Splicing of ZmbZIP60 can be elicited in maize seedlings by ER stress agents such as dithiothreitol (DTT or tunicamycin (TM or by heat treatment. Younger, rather than older seedlings display a more robust splicing response as do younger parts of leaf, along a developmental gradient in a leaf. The molecular signature of an ER stress response in plants includes the upregulation of Binding Protein (BIP genes. Maize has numerous BIP-like genes, and ER stress was found to upregulate one of these, ZmBIPb. Conclusions The splicing of ZmbZIP60 mRNA is an indicator of ER stress in maize seedlings resulting from adverse environmental conditions such as heat stress. ZmbZIP60 mRNA splicing in maize leads predictively to the formation of active bZIP transcription factor targeted to the nucleus to upregulate stress response genes. Among the genes upregulated by ER stress in maize is one of 22 BIP-like genes, ZmBIPb.
Zinc Transporter SLC39A7/ZIP7 Promotes Intestinal Epithelial Self-Renewal by Resolving ER Stress
Ohashi, Wakana; Kimura, Shunsuke; Iwanaga, Toshihiko; Furusawa, Yukihiro; Irié, Tarou; Izumi, Hironori; Watanabe, Takashi; Hara, Takafumi; Ohara, Osamu; Koseki, Haruhiko; Sato, Toshiro; Robine, Sylvie; Mori, Hisashi; Hattori, Yuichi; Mishima, Kenji; Ohno, Hiroshi; Hase, Koji; Fukada, Toshiyuki
2016-01-01
Zinc transporters play a critical role in spatiotemporal regulation of zinc homeostasis. Although disruption of zinc homeostasis has been implicated in disorders such as intestinal inflammation and aberrant epithelial morphology, it is largely unknown which zinc transporters are responsible for the intestinal epithelial homeostasis. Here, we show that Zrt-Irt-like protein (ZIP) transporter ZIP7, which is highly expressed in the intestinal crypt, is essential for intestinal epithelial proliferation. Mice lacking Zip7 in intestinal epithelium triggered endoplasmic reticulum (ER) stress in proliferative progenitor cells, leading to significant cell death of progenitor cells. Zip7 deficiency led to the loss of Olfm4+ intestinal stem cells and the degeneration of post-mitotic Paneth cells, indicating a fundamental requirement for Zip7 in homeostatic intestinal regeneration. Taken together, these findings provide evidence for the importance of ZIP7 in maintenance of intestinal epithelial homeostasis through the regulation of ER function in proliferative progenitor cells and maintenance of intestinal stem cells. Therapeutic targeting of ZIP7 could lead to effective treatment of gastrointestinal disorders. PMID:27736879
Zinc Transporter SLC39A7/ZIP7 Promotes Intestinal Epithelial Self-Renewal by Resolving ER Stress.
Directory of Open Access Journals (Sweden)
Wakana Ohashi
2016-10-01
Full Text Available Zinc transporters play a critical role in spatiotemporal regulation of zinc homeostasis. Although disruption of zinc homeostasis has been implicated in disorders such as intestinal inflammation and aberrant epithelial morphology, it is largely unknown which zinc transporters are responsible for the intestinal epithelial homeostasis. Here, we show that Zrt-Irt-like protein (ZIP transporter ZIP7, which is highly expressed in the intestinal crypt, is essential for intestinal epithelial proliferation. Mice lacking Zip7 in intestinal epithelium triggered endoplasmic reticulum (ER stress in proliferative progenitor cells, leading to significant cell death of progenitor cells. Zip7 deficiency led to the loss of Olfm4+ intestinal stem cells and the degeneration of post-mitotic Paneth cells, indicating a fundamental requirement for Zip7 in homeostatic intestinal regeneration. Taken together, these findings provide evidence for the importance of ZIP7 in maintenance of intestinal epithelial homeostasis through the regulation of ER function in proliferative progenitor cells and maintenance of intestinal stem cells. Therapeutic targeting of ZIP7 could lead to effective treatment of gastrointestinal disorders.
Czech Academy of Sciences Publication Activity Database
Gibalová, Antónia; Steinbachová, Lenka; Hafidh, Said; Bláhová, Veronika; Gadiou, Zuzana; Michailidis, Christos; Müller, Karel; Pleskot, Roman; Dupľáková, Nikoleta; Honys, David
2017-01-01
Roč. 30, č. 1 (2017), s. 1-17 ISSN 2194-7953 R&D Projects: GA ČR GA15-22720S; GA ČR(CZ) GA14-32292S; GA ČR GP13-41444P; GA MŠk(CZ) LD14109 Institutional support: RVO:61389030 Keywords : reticulum stress-response * transcription factor * arabidopsis-thaliana * molecular-interactions * plant transformation * gene-expression * heterodimerization * dimerization * evolution * specificity * bZIP * Transcription factors * Regulatory network * Male gametophyte * y2h * Pollen development Subject RIV: ED - Physiology OBOR OECD: Plant sciences, botany Impact factor: 2.629, year: 2016
A specific role for the ZipA protein in cell division: stabilization of the FtsZ protein.
Pazos, Manuel; Natale, Paolo; Vicente, Miguel
2013-02-01
In Escherichia coli, the cell division protein FtsZ is anchored to the cytoplasmic membrane by the action of the bitopic membrane protein ZipA and the cytoplasmic protein FtsA. Although the presence of both ZipA and FtsA is strictly indispensable for cell division, an FtsA gain-of-function mutant FtsA* (R286W) can bypass the ZipA requirement for cell division. This observation casts doubts on the role of ZipA and its need for cell division. Maxicells are nucleoid-free bacterial cells used as a whole cell in vitro system to probe protein-protein interactions without the need of protein purification. We show that ZipA protects FtsZ from the ClpXP-directed degradation observed in E. coli maxicells and that ZipA-stabilized FtsZ forms membrane-attached spiral-like structures in the bacterial cytoplasm. The overproduction of the FtsZ-binding ZipA domain is sufficient to protect FtsZ from degradation, whereas other C-terminal ZipA partial deletions lacking it are not. Individual overproduction of the proto-ring component FtsA or its gain-of-function mutant FtsA* does not result in FtsZ protection. Overproduction of FtsA or FtsA* together with ZipA does not interfere with the FtsZ protection. Moreover, neither FtsA nor FtsA* protects FtsZ when overproduced together with ZipA mutants lacking the FZB domain. We propose that ZipA protects FtsZ from degradation by ClpP by making the FtsZ site of interaction unavailable to the ClpX moiety of the ClpXP protease. This role cannot be replaced by either FtsA or FtsA*, suggesting a unique function for ZipA in proto-ring stability.
Nam, Yoonjae; Kwon, Kyonghee H; Lee, Sungjoon
2010-04-01
In an IDTV environment, which facilitates self-scheduling, skipping advertisements by zipping is an emerging ad-avoidance behavior. This study explores whether an alternative ad format, called simultaneous presentation advertising (SPA), may overcome the limitations of classical sequential advertising (CSA) in controlling zipping behavior and increasing the effectiveness of ads. The experiment revealed that SPA is more effective than CSA in reducing zipping and increasing recall, but SPA was more intrusive and produced a negative product image. There was no difference regarding cognitive avoidance. This work discusses the implications of these findings in the interactive media environment.
Logarithmic solution to the line-polygon intersection problem. 127
International Nuclear Information System (INIS)
Siddon, R.L.; Barth, N.H.
1987-01-01
Algorithmic solution for a special case of the line - polygon intersection problem has been developed. The special case involves repeated solution to the problem where one point on the line is held fixed and the other allowed to vary. In addition, the fixed point on the line must lie outside the rectangle defined by the extrema of the polygon and varying point. In radiotherapy applications, the fixed point corresponds to the source of radiation, whereas the varying points refer to the grid of multiple calculation points. For smooth contours of 100-200 vertices, it is found that the new algorithm results in a CPU savings of approximately a factor of 3-5. 3 refs.; 4 figs
Exact moduli space metrics for hyperbolic vortex polygons
International Nuclear Information System (INIS)
Krusch, S.; Speight, J. M.
2010-01-01
Exact metrics on some totally geodesic submanifolds of the moduli space of static hyperbolic N-vortices are derived. These submanifolds, denoted as Σ n,m , are spaces of C n -invariant vortex configurations with n single vortices at the vertices of a regular polygon and m=N-n coincident vortices at the polygon's center. The geometric properties of Σ n,m are investigated, and it is found that Σ n,n-1 is isometric to the hyperbolic plane of curvature -(3πn) -1 . The geodesic flow on Σ n,m and a geometrically natural variant of geodesic flow recently proposed by Collie and Tong ['The dynamics of Chern-Simons vortices', Phys. Rev. D Part. Fields Gravit. Cosmol. 78, 065013 (2008);e-print arXiv:hep-th/0805.0602] are analyzed in detail.
Electron localization and optical absorption of polygonal quantum rings
Sitek, Anna; Serra, Llorenç; Gudmundsson, Vidar; Manolescu, Andrei
2015-06-01
We investigate theoretically polygonal quantum rings and focus mostly on the triangular geometry where the corner effects are maximal. Such rings can be seen as short core-shell nanowires, a generation of semiconductor heterostructures with multiple applications. We show how the geometry of the sample determines the electronic energy spectrum, and also the localization of electrons, with effects on the optical absorption. In particular, we show that irrespective of the ring shape low-energy electrons are always attracted by corners and are localized in their vicinity. The absorption spectrum in the presence of a magnetic field shows only two peaks within the corner-localized state domain, each associated with different circular polarization. This picture may be changed by an external electric field which allows previously forbidden transitions, and thus enables the number of corners to be determined. We show that polygonal quantum rings allow absorption of waves from distant ranges of the electromagnetic spectrum within one sample.
QUADRATIC SERENDIPITY FINITE ELEMENTS ON POLYGONS USING GENERALIZED BARYCENTRIC COORDINATES.
Rand, Alexander; Gillette, Andrew; Bajaj, Chandrajit
2014-01-01
We introduce a finite element construction for use on the class of convex, planar polygons and show it obtains a quadratic error convergence estimate. On a convex n -gon, our construction produces 2 n basis functions, associated in a Lagrange-like fashion to each vertex and each edge midpoint, by transforming and combining a set of n ( n + 1)/2 basis functions known to obtain quadratic convergence. The technique broadens the scope of the so-called 'serendipity' elements, previously studied only for quadrilateral and regular hexahedral meshes, by employing the theory of generalized barycentric coordinates. Uniform a priori error estimates are established over the class of convex quadrilaterals with bounded aspect ratio as well as over the class of convex planar polygons satisfying additional shape regularity conditions to exclude large interior angles and short edges. Numerical evidence is provided on a trapezoidal quadrilateral mesh, previously not amenable to serendipity constructions, and applications to adaptive meshing are discussed.
Selection of industrial robots using the Polygons area method
Directory of Open Access Journals (Sweden)
Mortaza Honarmande Azimi
2014-08-01
Full Text Available Selection of robots from the several proposed alternatives is a very important and tedious task. Decision makers are not limited to one method and several methods have been proposed for solving this problem. This study presents Polygons Area Method (PAM as a multi attribute decision making method for robot selection problem. In this method, the maximum polygons area obtained from the attributes of an alternative robot on the radar chart is introduced as a decision-making criterion. The results of this method are compared with other typical multiple attribute decision-making methods (SAW, WPM, TOPSIS, and VIKOR by giving two examples. To find similarity in ranking given by different methods, Spearman’s rank correlation coefficients are obtained for different pairs of MADM methods. It was observed that the introduced method is in good agreement with other well-known MADM methods in the robot selection problem.
Invariant polygons in systems with grazing-sliding.
Szalai, R; Osinga, H M
2008-06-01
The paper investigates generic three-dimensional nonsmooth systems with a periodic orbit near grazing-sliding. We assume that the periodic orbit is unstable with complex multipliers so that two dominant frequencies are present in the system. Because grazing-sliding induces a dimension loss and the instability drives every trajectory into sliding, the system has an attractor that consists of forward sliding orbits. We analyze this attractor in a suitably chosen Poincare section using a three-parameter generalized map that can be viewed as a normal form. We show that in this normal form the attractor must be contained in a finite number of lines that intersect in the vertices of a polygon. However the attractor is typically larger than the associated polygon. We classify the number of lines involved in forming the attractor as a function of the parameters. Furthermore, for fixed values of parameters we investigate the one-dimensional dynamics on the attractor.
Extending backward polygon beam tracing to glossy scattering surfaces
CSIR Research Space (South Africa)
Duvenhage, B
2011-05-01
Full Text Available to render caustics that could not otherwise be sim- ulated efficiently using the high fidelity forward raytracing and radiosity rendering techniques of the time. Similar to what Heckbert and Hanrahan proposed, Watt [Wat90] used backward polygon beam....: Adaptive radiosity textures for bidi- rectional ray tracing. In SIGGRAPH ?90: Proceedings of the 17th Annual Conference on Computer graphics and Interactive Techniques (New York, NY, USA, 1990), ACM Press, New York, pp. 145?154. [HH84] HECKBERT P. S...
Fat polygonal partitions with applications to visualization and embeddings
Directory of Open Access Journals (Sweden)
Mark de Berg
2013-12-01
Full Text Available Let T be a rooted and weighted tree, where the weight of any node is equal to the sum of the weights of its children. The popular Treemap algorithm visualizes such a tree as a hierarchical partition of a square into rectangles, where the area of the rectangle corresponding to any node in T is equal to the weight of that node. The aspect ratio of the rectangles in such a rectangular partition necessarily depends on the weights and can become arbitrarily high.We introduce a new hierarchical partition scheme, called a polygonal partition, which uses convex polygons rather than just rectangles. We present two methods for constructing polygonal partitions, both having guarantees on the worst-case aspect ratio of the constructed polygons; in particular, both methods guarantee a bound on the aspect ratio that is independent of the weights of the nodes.We also consider rectangular partitions with slack, where the areas of the rectangles may differ slightly from the weights of the corresponding nodes. We show that this makes it possible to obtain partitions with constant aspect ratio. This result generalizes to hyper-rectangular partitions in ℝd. We use these partitions with slack for embedding ultrametrics into d-dimensional Euclidean space: we give a polylog(Δ-approximation algorithm for embedding n-point ultrametrics into ℝd with minimum distortion, where Δ denotes the spread of the metric. The previously best-known approximation ratio for this problem was polynomial in n. This is the first algorithm for embedding a non-trivial family of weighted-graph metrics into a space of constant dimension that achieves polylogarithmic approximation ratio.
Measured Hydrologic Storage Characteristics of Three Major Ice Wedge Polygon Types, Barrow, Alaska
Chamberlain, A. J.; Liljedahl, A.; Wilson, C. J.; Cable, W.; Romanovsky, V. E.
2014-12-01
Model simulations have suggested that the hydrologic fluxes and stores of Arctic wetlands are constrained by the micro-topographical features of ice wedge polygons, which are abundant in lowland tundra landscapes. Recently observed changes in ice wedge polygon landscapes - in particular, ice wedge degradation and trough formation - emphasize the need to better understand how differing ice wedge polygon morphologies affect the larger hydrologic system. Here we present three seasons of measured end-of-winter snow accumulation, continuous soil moisture and water table elevations, and repeated frost table mapping. Together, these describe the hydrologic characteristics of three main ice wedge polygon types: low centered polygons with limited trough development (representative of a ~500 year old vegetated drained thaw lake basin), and low- and high-centered polygons with well-defined troughs. Dramatic spatiotemporal variability exists both between polygon types and between the features of an individual polygon (e.g. troughs, centers, rims). Landscape-scale end-of-winter snow water equivalent is similar between polygon types, while the sub-polygon scale distribution of the surface water differs, both as snow and as ponded water. Some sub-polygon features appear buffered against large variations in water levels, while others display periods of prolonged recessions and large responses to rain events. Frost table elevations in general mimic the ground surface topography, but with spatiotemporal variability in thaw rate. The studied thaw seasons represented above long-term average rainfall, and in 2014, record high June precipitation. Differing ice wedge polygon types express dramatically different local hydrology, despite nearly identical climate forcing and landscape-scale snow accumulation, making ice wedge polygons an important component when describing the Arctic water, nutrient and energy system.
Directory of Open Access Journals (Sweden)
Ahmet Yanık
2013-03-01
Full Text Available The aim of the study is to investigate the development of 7th Grade students’ skills to define, construct and classify polygons in geometry course with Cabri Geometry II Plus software geometry, an example of dynamic geometry software. The study used qualitative and quantitative research methods in accordance with the research objectives and focus, so it was designed as a mixed method research. The participants of the study were 21 7th Grade students, 11 girls and 10 boys, who were attending a secondary school in Eskişehir city center during 2012-2013 school year. As a source of qualitative data, four students in this class were selected for the interview. The data were collected with “Polygon Identification and Classification Scale”, one group pre-test and post-test in order to determine the level of development and significance level of the gender variable, and Cabri Geometry worksheets developed by the researchers. The quantitative data were analyzed with SPSS Statistics 20. Also, t-test and Wilcoxon test were used in data analysis. The data obtained from the interviews were analyzed through descriptive analysis. The qualitative data showed that the mean of correct answers given by the students to the questions in the Polygon Identification and Classification Scale was higher in the post-test than the pre-test. The ttest results for the pre-test and post-test mean scores and the results of the paired samples test showed a significant difference in favor of the post-test. There was no significant difference based on the gender variable. On the other hand, the data obtained from the interviews were coded under five different themes. The activities about the concept of formation showed that incorrect formations caused incorrect generalizations about the shapes. The study found that, as a result of the teaching practice in the study, hierarchical relations among polygons were expressed correctly. Finally, after the practice, the
A Novel Polygonal Finite Element Method: Virtual Node Method
Tang, X. H.; Zheng, C.; Zhang, J. H.
2010-05-01
Polygonal finite element method (PFEM), which can construct shape functions on polygonal elements, provides greater flexibility in mesh generation. However, the non-polynomial form of traditional PFEM, such as Wachspress method and Mean Value method, leads to inexact numerical integration. Since the integration technique for non-polynomial functions is immature. To overcome this shortcoming, a great number of integration points have to be used to obtain sufficiently exact results, which increases computational cost. In this paper, a novel polygonal finite element method is proposed and called as virtual node method (VNM). The features of present method can be list as: (1) It is a PFEM with polynomial form. Thereby, Hammer integral and Gauss integral can be naturally used to obtain exact numerical integration; (2) Shape functions of VNM satisfy all the requirements of finite element method. To test the performance of VNM, intensive numerical tests are carried out. It found that, in standard patch test, VNM can achieve significantly better results than Wachspress method and Mean Value method. Moreover, it is observed that VNM can achieve better results than triangular 3-node elements in the accuracy test.
Properties of regular polygons of coupled microring resonators.
Chremmos, Ioannis; Uzunoglu, Nikolaos
2007-11-01
The resonant properties of a closed and symmetric cyclic array of N coupled microring resonators (coupled-microring resonator regular N-gon) are for the first time determined analytically by applying the transfer matrix approach and Floquet theorem for periodic propagation in cylindrically symmetric structures. By solving the corresponding eigenvalue problem with the field amplitudes in the rings as eigenvectors, it is shown that, for even or odd N, this photonic molecule possesses 1 + N/2 or 1+N resonant frequencies, respectively. The condition for resonances is found to be identical to the familiar dispersion equation of the infinite coupled-microring resonator waveguide with a discrete wave vector. This result reveals the so far latent connection between the two optical structures and is based on the fact that, for a regular polygon, the field transfer matrix over two successive rings is independent of the polygon vertex angle. The properties of the resonant modes are discussed in detail using the illustration of Brillouin band diagrams. Finally, the practical application of a channel-dropping filter based on polygons with an even number of rings is also analyzed.
Fast incorporation of optical flow into active polygons.
Unal, Gozde; Krim, Hamid; Yezzi, Anthony
2005-06-01
In this paper, we first reconsider, in a different light, the addition of a prediction step to active contour-based visual tracking using an optical flow and clarify the local computation of the latter along the boundaries of continuous active contours with appropriate regularizers. We subsequently detail our contribution of computing an optical flow-based prediction step directly from the parameters of an active polygon, and of exploiting it in object tracking. This is in contrast to an explicitly separate computation of the optical flow and its ad hoc application. It also provides an inherent regularization effect resulting from integrating measurements along polygon edges. As a result, we completely avoid the need of adding ad hoc regularizing terms to the optical flow computations, and the inevitably arbitrary associated weighting parameters. This direct integration of optical flow into the active polygon framework distinguishes this technique from most previous contour-based approaches, where regularization terms are theoretically, as well as practically, essential. The greater robustness and speed due to a reduced number of parameters of this technique are additional and appealing features.
PolyRES: A polygon-based Richards equation solver
International Nuclear Information System (INIS)
Hills, R.G.
1995-12-01
This document describes the theory, implementation, and use of a software package designed to solve the transient, two-dimensional, Richards equation for water flow in unsaturated-saturated soils. This package was specifically designed to model complex geometries with minimal input from the user and to simulate groundwater flow related to assessment of low-level radioactive waste disposal sites and engineered facilities. The spatial variation of the hydraulic properties can be defined across individual polygon-shaped subdomains, called objects. These objects combine to form a polygon-shaped model domain. Each object can have its own distribution of hydraulic parameters. The resulting model domain and polygon-shaped internal objects are mapped onto a rectangular, finite-volume, computational grid by a preprocessor. This allows the user to specify model geometry independently of the underlying grid and greatly simplifies user input for complex geometries. In addition, this approach significantly reduces the computational requirements since complex geometries are actually modeled on a rectangular grid. This results in well-structured, finite difference-like systems of equations that require minimal storage and are very efficient to solve. The documentation for this software package includes a user's manual, a detailed description of the underlying theory, and a detailed discussion of program flow. Several example problems are presented that show the use and features of the software package. The water flow predictions for several of these example problems are compared to those of another algorithm to test for prediction equivalency
A model of anelastic relaxation associated with polygonization boundary
International Nuclear Information System (INIS)
Yan, S.C.
1990-01-01
A model of anelastic relaxation associated with polygonization boundary is proposed in order to explain internal friction peaks and other experimental phenomena observed recently. The model, which is referred to as vacancy-thermal jog model, shows that under conditions of high temperature and low applied stress with lower frequencies of vibration, thermal jog pairs are generated on dislocation segments of the boundaries. These jogs are in saturation with vacancies in the vicinity of them, and the vacancy current due to the concentration gradient of vacancy drifts among the boundaries. As a result, a diffusional creep is produced and a part of energy is dissipated. For vacancy drift, it is required that the thermal jogs emit (absorb) vacancies, which brings climbing bow of segments into operation, and another part of energy is dissipated so that there are two parts of energy dissipated in the strain process connected with polygonization boundary. Based on this point of view, the mathematical expressions of internal friction and modulus defect associated with polygonization boundary were subsequently derived and found to be in satisfactory agreement with experiments. (author). 13 refs, 6 figs
Curvature of random walks and random polygons in confinement
International Nuclear Information System (INIS)
Diao, Y; Ernst, C; Montemayor, A; Ziegler, U
2013-01-01
The purpose of this paper is to study the curvature of equilateral random walks and polygons that are confined in a sphere. Curvature is one of several basic geometric properties that can be used to describe random walks and polygons. We show that confinement affects curvature quite strongly, and in the limit case where the confinement diameter equals the edge length the unconfined expected curvature value doubles from π/2 to π. To study curvature a simple model of an equilateral random walk in spherical confinement in dimensions 2 and 3 is introduced. For this simple model we derive explicit integral expressions for the expected value of the total curvature in both dimensions. These expressions are functions that depend only on the radius R of the confinement sphere. We then show that the values obtained by numeric integration of these expressions agrees with numerical average curvature estimates obtained from simulations of random walks. Finally, we compare the confinement effect on curvature of random walks with random polygons. (paper)
Electronic properties of carbon nanotubes with polygonized cross sections
International Nuclear Information System (INIS)
Charlier, J.; Lambin, P.; Ebbesen, T.
1996-01-01
The electronic properties of carbon nanotubes having polygonized cross sections instead of purely circular ones, such as recently observed using transmission electron microscopy, are investigated with plane-wave ab initio pseudopotential local-density-functional calculations and simple tight-binding models. Strong σ * -π * hybridization effects occur in zigzag nanotubes due to the high curvature located near the edges of the polygonal cross-section prism. These effects, combined with a lowering of symmetry, dramatically affect the electronic properties of the nanotubes. It is found that modified low-lying conduction-band states are introduced either into the bandgap of insulating nanotubes, or below the degenerate states that form the top of the valence band of metallic nanotubes, leading the corresponding nanostructures to be metals, semimetals, or at least very-small-gap semiconductors. The degree of the polygon representing the cross section of the tube, and the sharpness of the edge angles, are found to be major factors in the hybridization effect, and consequently govern the electronic behavior at the Fermi level. copyright 1996 The American Physical Society
The average crossing number of equilateral random polygons
International Nuclear Information System (INIS)
Diao, Y; Dobay, A; Kusner, R B; Millett, K; Stasiak, A
2003-01-01
In this paper, we study the average crossing number of equilateral random walks and polygons. We show that the mean average crossing number ACN of all equilateral random walks of length n is of the form (3/16)n ln n + O(n). A similar result holds for equilateral random polygons. These results are confirmed by our numerical studies. Furthermore, our numerical studies indicate that when random polygons of length n are divided into individual knot types, the for each knot type K can be described by a function of the form = a(n-n 0 )ln(n-n 0 ) + b(n-n 0 ) + c where a, b and c are constants depending on K and n 0 is the minimal number of segments required to form K. The profiles diverge from each other, with more complex knots showing higher than less complex knots. Moreover, the profiles intersect with the profile of all closed walks. These points of intersection define the equilibrium length of K, i.e., the chain length n e (K) at which a statistical ensemble of configurations with given knot type K-upon cutting, equilibration and reclosure to a new knot type K'-does not show a tendency to increase or decrease . This concept of equilibrium length seems to be universal, and applies also to other length-dependent observables for random knots, such as the mean radius of gyration g >
Tao, Yan-ting; Huang, Qing; Jiang, Ya-li; Wang, Xiao-lei; Sun, Ping; Tian, Yuanyuan; Wu, Hai-liang; Zhang, Min; Meng, Si-bo; Wang, Yu-shu; Sun, Qing; Zhang, Lian-ying
2013-08-01
Zinc is the most common trace mineral after iron in the human body. In organisms, zinc transporters help zinc influx and efflux from cells. A previous study has reported that Zip2 was up-regulated over 27-fold in human monocytic THP-1 cells, when intracellular zinc was depleted by TPEN. Our study found Zip2 was over-expressed in leukocytes of asthmatic infants, especially those in which the serum zinc level was lower than those in healthy infants. Pulmonary tuberculosis (PTB) patients have significantly low serum zinc levels. Here we investigated whether Zip2 level was changed in the patients with PTB. Zip2 mRNA and protein levels in peripheral blood mononuclear cells (PBMC) from PTB (n1=23) and healthy controls (n2=42) were detected by quantitative real-time PCR and western blot, respectively. mRNA expression levels of another four zinc transporters, Zip1, Zip6, Zip8 and ZnT1, were detected by quantitative real-time PCR. Zip2 mRNA level was significantly up-regulated in PTB patients (P=0.001), and Zip8 mRNA level was significantly down-regulated compared with control individuals (Plevels of Zip1, Zip6 and ZnT1 in either group (P>0.05). Zip2 protein expression levels increased in PTB patients compared with control individuals. Our study found that knockdown of ZIP2 with siRNA caused a decrease in Zip2 levels in PBMC of PTB patients, while reducing the expression of INF-γ (Pinitial infection control of the human body, by promoting and maintaining the immune response of adaptive T cells.
The use of ZIP and CART to model cryptosporidiosis in relation to climatic variables.
Hu, Wenbiao; Mengersen, Kerrie; Fu, Shiu-Yun; Tong, Shilu
2010-07-01
This research assesses the potential impact of weekly weather variability on the incidence of cryptosporidiosis disease using time series zero-inflated Poisson (ZIP) and classification and regression tree (CART) models. Data on weather variables, notified cryptosporidiosis cases and population size in Brisbane were supplied by the Australian Bureau of Meteorology, Queensland Department of Health, and Australian Bureau of Statistics, respectively. Both time series ZIP and CART models show a clear association between weather variables (maximum temperature, relative humidity, rainfall and wind speed) and cryptosporidiosis disease. The time series CART models indicated that, when weekly maximum temperature exceeded 31 degrees C and relative humidity was less than 63%, the relative risk of cryptosporidiosis rose by 13.64 (expected morbidity: 39.4; 95% confidence interval: 30.9-47.9). These findings may have applications as a decision support tool in planning disease control and risk-management programs for cryptosporidiosis disease.
Exploring the bZIP transcription factor regulatory network in Neurospora crassa.
Tian, Chaoguang; Li, Jingyi; Glass, N Louise
2011-03-01
Transcription factors (TFs) are key nodes of regulatory networks in eukaryotic organisms, including filamentous fungi such as Neurospora crassa. The 178 predicted DNA-binding TFs in N. crassa are distributed primarily among six gene families, which represent an ancient expansion in filamentous ascomycete genomes; 98 TF genes show detectable expression levels during vegetative growth of N. crassa, including 35 that show a significant difference in expression level between hyphae at the periphery versus hyphae in the interior of a colony. Regulatory networks within a species genome include paralogous TFs and their respective target genes (TF regulon). To investigate TF network evolution in N. crassa, we focused on the basic leucine zipper (bZIP) TF family, which contains nine members. We performed baseline transcriptional profiling during vegetative growth of the wild-type and seven isogenic, viable bZIP deletion mutants. We further characterized the regulatory network of one member of the bZIP family, NCU03905. NCU03905 encodes an Ap1-like protein (NcAp-1), which is involved in resistance to multiple stress responses, including oxidative and heavy metal stress. Relocalization of NcAp-1 from the cytoplasm to the nucleus was associated with exposure to stress. A comparison of the NcAp-1 regulon with Ap1-like regulons in Saccharomyces cerevisiae, Schizosaccharomyces pombe, Candida albicans and Aspergillus fumigatus showed both conservation and divergence. These data indicate how N. crassa responds to stress and provide information on pathway evolution.
The transcription factor bZIP14 regulates the TCA cycle in the diatom Phaeodactylum tricornutum.
Matthijs, Michiel; Fabris, Michele; Obata, Toshihiro; Foubert, Imogen; Franco-Zorrilla, José Manuel; Solano, Roberto; Fernie, Alisdair R; Vyverman, Wim; Goossens, Alain
2017-06-01
Diatoms are amongst the most important marine microalgae in terms of biomass, but little is known concerning the molecular mechanisms that regulate their versatile metabolism. Here, the pennate diatom Phaeodactylum tricornutum was studied at the metabolite and transcriptome level during nitrogen starvation and following imposition of three other stresses that impede growth. The coordinated upregulation of the tricarboxylic acid (TCA) cycle during the nitrogen stress response was the most striking observation. Through co-expression analysis and DNA binding assays, the transcription factor bZIP14 was identified as a regulator of the TCA cycle, also beyond the nitrogen starvation response, namely in diurnal regulation. Accordingly, metabolic and transcriptional shifts were observed upon overexpression of bZIP14 in transformed P. tricornutum cells. Our data indicate that the TCA cycle is a tightly regulated and important hub for carbon reallocation in the diatom cell during nutrient starvation and that bZIP14 is a conserved regulator of this cycle. © 2017 The Authors.
Coding chaotic billiards. Pt. 2
International Nuclear Information System (INIS)
Giannoni, M.J.; Ullmo, D.
1993-01-01
A method was proposed earlier to derive exact symbolic dynamics for polygonal billiards defined on a negative curvature surface, whose all vertices lie at infinity. This method is now extended to the case of compact billiards tiling the Poincare disk, using elementary tools such as the bounce mapping. An exact coding is derived also in this case. Furthermore, some results are obtained without using the tiling property. They allow to tackle the more complicated case of non-tiling billiards. (authors). 18 refs., 13 figs
Directory of Open Access Journals (Sweden)
Xiangyu Chen
2015-12-01
Full Text Available Interhomolog crossovers promote proper chromosome segregation during meiosis and are formed by the regulated repair of programmed double-strand breaks. This regulation requires components of the synaptonemal complex (SC, a proteinaceous structure formed between homologous chromosomes. In yeast, SC formation requires the "ZMM" genes, which encode a functionally diverse set of proteins, including the transverse filament protein, Zip1. In wild-type meiosis, Zmm proteins promote the biased resolution of recombination intermediates into crossovers that are distributed throughout the genome by interference. In contrast, noncrossovers are formed primarily through synthesis-dependent strand annealing mediated by the Sgs1 helicase. This work identifies a conserved region on the C terminus of Zip1 (called Zip1 4S, whose phosphorylation is required for the ZMM pathway of crossover formation. Zip1 4S phosphorylation is promoted both by double-strand breaks (DSBs and the meiosis-specific kinase, MEK1/MRE4, demonstrating a role for MEK1 in the regulation of interhomolog crossover formation, as well as interhomolog bias. Failure to phosphorylate Zip1 4S results in meiotic prophase arrest, specifically in the absence of SGS1. This gain of function meiotic arrest phenotype is suppressed by spo11Δ, suggesting that it is due to unrepaired breaks triggering the meiotic recombination checkpoint. Epistasis experiments combining deletions of individual ZMM genes with sgs1-md zip1-4A indicate that Zip1 4S phosphorylation functions prior to the other ZMMs. These results suggest that phosphorylation of Zip1 at DSBs commits those breaks to repair via the ZMM pathway and provides a mechanism by which the crossover/noncrossover decision can be dynamically regulated during yeast meiosis.
Overexpression of ZmIRT1 and ZmZIP3 Enhances Iron and Zinc Accumulation in Transgenic Arabidopsis.
Directory of Open Access Journals (Sweden)
Suzhen Li
Full Text Available Iron and zinc are important micronutrients for both the growth and nutrient availability of crop plants, and their absorption is tightly controlled by a metal uptake system. Zinc-regulated transporters, iron-regulated transporter-like proteins (ZIP, is considered an essential metal transporter for the acquisition of Fe and Zn in graminaceous plants. Several ZIPs have been identified in maize, although their physiological function remains unclear. In this report, ZmIRT1 was shown to be specifically expressed in silk and embryo, whereas ZmZIP3 was a leaf-specific gene. Both ZmIRT1 and ZmZIP3 were shown to be localized to the plasma membrane and endoplasmic reticulum. In addition, transgenic Arabidopsis plants overexpressing ZmIRT1 or ZmZIP3 were generated, and the metal contents in various tissues of transgenic and wild-type plants were examined based on ICP-OES and Zinpyr-1 staining. The Fe and Zn concentration increased in roots and seeds of ZmIRT1-overexpressing plants, while the Fe content in shoots decreased. Overexpressing ZmZIP3 enhanced Zn accumulation in the roots of transgenic plants, while that in shoots was repressed. In addition, the transgenic plants showed altered tolerance to various Fe and Zn conditions compared with wild-type plants. Furthermore, the genes associated with metal uptake were stimulated in ZmIRT1 transgenic plants, while those involved in intra- and inter- cellular translocation were suppressed. In conclusion, ZmIRT1 and ZmZIP3 are functional metal transporters with different ion selectivities. Ectopic overexpression of ZmIRT1 may stimulate endogenous Fe uptake mechanisms, which may facilitate metal uptake and homeostasis. Our results increase our understanding of the functions of ZIP family transporters in maize.
Directory of Open Access Journals (Sweden)
Sunil Kumar Thalor
Full Text Available Sucrose is known to repress the translation of Arabidopsis thaliana AtbZIP11 transcript which encodes a protein belonging to the group of S (S--stands for small basic region-leucine zipper (bZIP-type transcription factor. This repression is called sucrose-induced repression of translation (SIRT. It is mediated through the sucrose-controlled upstream open reading frame (SC-uORF found in the AtbZIP11 transcript. The SIRT is reported for 4 other genes belonging to the group of S bZIP in Arabidopsis. Tobacco tbz17 is phylogenetically closely related to AtbZIP11 and carries a putative SC-uORF in its 5'-leader region. Here we demonstrate that tbz17 exhibits SIRT mediated by its SC-uORF in a manner similar to genes belonging to the S bZIP group of the Arabidopsis genus. Furthermore, constitutive transgenic expression of tbz17 lacking its 5'-leader region containing the SC-uORF leads to production of tobacco plants with thicker leaves composed of enlarged cells with 3-4 times higher sucrose content compared to wild type plants. Our finding provides a novel strategy to generate plants with high sucrose content.
Thalor, Sunil Kumar; Berberich, Thomas; Lee, Sung Shin; Yang, Seung Hwan; Zhu, Xujun; Imai, Ryozo; Takahashi, Yoshihiro; Kusano, Tomonobu
2012-01-01
Sucrose is known to repress the translation of Arabidopsis thaliana AtbZIP11 transcript which encodes a protein belonging to the group of S (S--stands for small) basic region-leucine zipper (bZIP)-type transcription factor. This repression is called sucrose-induced repression of translation (SIRT). It is mediated through the sucrose-controlled upstream open reading frame (SC-uORF) found in the AtbZIP11 transcript. The SIRT is reported for 4 other genes belonging to the group of S bZIP in Arabidopsis. Tobacco tbz17 is phylogenetically closely related to AtbZIP11 and carries a putative SC-uORF in its 5'-leader region. Here we demonstrate that tbz17 exhibits SIRT mediated by its SC-uORF in a manner similar to genes belonging to the S bZIP group of the Arabidopsis genus. Furthermore, constitutive transgenic expression of tbz17 lacking its 5'-leader region containing the SC-uORF leads to production of tobacco plants with thicker leaves composed of enlarged cells with 3-4 times higher sucrose content compared to wild type plants. Our finding provides a novel strategy to generate plants with high sucrose content.
Small-Scale Polygons and the History of Ground Ice on Mars
Mellon, Michael T.
2000-01-01
This research has laid a foundation for continued study of permafrost polygons on Mars using the models and understanding discussed here. Further study of polygonal patterns on Mars is proceeding (under new funding) which is expected to reveal more results about the origin of observed martian polygons and what information they contain regarding the recent history of tile martian climate and of water ice on Mars.
Directory of Open Access Journals (Sweden)
Marina Gálvez-Peralta
Full Text Available Previously this laboratory characterized Slc39a8-encoded ZIP8 as a Zn(2+/(HCO(3(-(2 symporter; yet, the overall physiological importance of ZIP8 at the whole-organism level remains unclear. Herein we describe the phenotype of the hypomorphic Slc39a8(neo/neo mouse which has retained the neomycin-resistance gene in intron 3, hence causing significantly decreased ZIP8 mRNA and protein levels in embryo, fetus, placenta, yolk sac, and several tissues of neonates. The Slc39a8(neo allele is associated with diminished zinc and iron uptake in mouse fetal fibroblast and liver-derived cultures; consequently, Slc39a8(neo/neo newborns exhibit diminished zinc and iron levels in several tissues. Slc39a8(neo/neo homozygotes from gestational day(GD-11.5 onward are pale, growth-stunted, and die between GD18.5 and 48 h postnatally. Defects include: severely hypoplastic spleen; hypoplasia of liver, kidney, lung, and lower limbs. Histologically, Slc39a8(neo/neo neonates show decreased numbers of hematopoietic islands in yolk sac and liver. Low hemoglobin, hematocrit, red cell count, serum iron, and total iron-binding capacity confirmed severe anemia. Flow cytometry of fetal liver cells revealed the erythroid series strikingly affected in the hypomorph. Zinc-dependent 5-aminolevulinic acid dehydratase, required for heme synthesis, was not different between Slc39a8(+/+ and Slc39a8(neo/neo offspring. To demonstrate further that the mouse phenotype is due to ZIP8 deficiency, we bred Slc39a8(+/neo with BAC-transgenic BTZIP8-3 line (carrying three extra copies of the Slc39a8 allele; this cross generated viable Slc39a8(neo/neo_BTZIP8-3(+/+ pups showing none of the above-mentioned congenital defects-proving Slc39a8(neo/neo causes the described phenotype. Our study demonstrates that ZIP8-mediated zinc transport plays an unappreciated critical role during in utero and neonatal growth, organ morphogenesis, and hematopoiesis.
Material parameters characterization for arbitrary N-sided regular polygonal invisible cloak
International Nuclear Information System (INIS)
Wu Qun; Zhang Kuang; Meng Fanyi; Li Lewei
2009-01-01
Arbitrary N-sided regular polygonal cylindrical cloaks are proposed and designed based on the coordinate transformation theory. First, the general expressions of constitutive tensors of the N-sided regular polygonal cylindrical cloaks are derived, then there are some full-wave simulations of the cloaks that are composed of inhomogeneous and anisotropic metamaterials, which will bend incoming electromagnetic waves and guide them to propagate around the inner region; such electromagnetic waves will return to their original propagation directions without distorting the waves outside the polygonal cloak. The results of full-wave simulations validate the general expressions of constitutive tensors of the N-sided regular polygonal cylindrical cloaks we derived.
A numerical investigation of sub-wavelength resonances in polygonal metamaterial cylinders
DEFF Research Database (Denmark)
Arslanagic, Samel; Breinbjerg, Olav
2009-01-01
The sub-wavelength resonances, known to exist in metamaterial radiators and scatterers of circular cylindrical shape, are investigated with the aim of determining if these resonances also exist for polygonal cylinders and, if so, how they are affected by the shape of the polygon. To this end, a set...... of polygonal cylinders excited by a nearby electric line current is analyzed numerically and it is shown, through detailed analysis of the near-field distribution and radiation resistance, that these polygonal cylinders do indeed support sub-wavelength resonances similar to those of the circular cylinders...
Engaging student expeditionary units to land work at aerospace polygons
Directory of Open Access Journals (Sweden)
Ирина Жемерова
2016-10-01
Full Text Available To organize the aerospace polygon it is necessary to conduct a large number of measurement and descriptive works. First and foremost is working with the fund and cartographic material. The map of the landfill shows the most important objects and phenomena: quarries, sinkholes, deep ravines, industrial, residential and protected areas. Organization of the aerospace polygon operation involves large labour costs. To train professionals on the ground research of the earth’s cover remote sensing, we have organized a permanent student expedition. Prior to the start of work, students listen to a series of introductory lectures on remote sensing, principles of ground work, methods of statistical evaluation, basic methods of data collection and processing. This article covers one direction of work - collecting and processing of phytometric data of crops and steppe vegetation in the Streletskaya steppe in the Central Chernozem nature reserve. The work is carried out on the test area of Kursk aerospace polygon, organized on the basis of Kursk biospheric station of the Institute of Geography RAS. A generally accepted method of test platforms is used on the routes. The results of measurements and observations are recorded in a field book. Species diversity, plant height, projective cover and crops density are determined on the sample area by the instrumental and visual methods. The rest phytometric indexes are calculated in laboratory conditions. The students can use the resulting material when writing articles, course and degree works. At the site, students acquire skills of working in field conditions with natural objects, collecting and processing of information by various methods, expanding understanding of the need and importance of the earth surface study by remote sensing methods.
The Knot Spectrum of Confined Random Equilateral Polygons
Directory of Open Access Journals (Sweden)
Diao Y.
2014-01-01
Full Text Available It is well known that genomic materials (long DNA chains of living organisms are often packed compactly under extreme confining conditions using macromolecular self-assembly processes but the general DNA packing mechanism remains an unsolved problem. It has been proposed that the topology of the packed DNA may be used to study the DNA packing mechanism. For example, in the case of (mutant bacteriophage P4, DNA molecules packed inside the bacteriophage head are considered to be circular since the two sticky ends of the DNA are close to each other. The DNAs extracted from the capsid without separating the two ends can thus preserve the topology of the (circular DNAs. It turns out that the circular DNAs extracted from bacteriophage P4 are non-trivially knotted with very high probability and with a bias toward chiral knots. In order to study this problem using a systematic approach based on mathematical modeling, one needs to introduce a DNA packing model under extreme volume confinement condition and test whether such a model can produce the kind of knot spectrum observed in the experiments. In this paper we introduce and study a model of equilateral random polygons con_ned in a sphere. This model is not meant to generate polygons that model DNA packed in a virus head directly. Instead, the average topological characteristics of this model may serve as benchmark data for totally randomly packed circular DNAs. The difference between the biologically observed topological characteristics and our benchmark data might reveal the bias of DNA packed in the viral capsids and possibly lead to a better understanding of the DNA packing mechanism, at least for the bacteriophage DNA. The purpose of this paper is to provide information about the knot spectrum of equilateral random polygons under such a spherical confinement with length and confinement ratios in a range comparable to circular DNAs packed inside bacteriophage heads.
Giant polygons and mounds in the lowlands of Mars: signatures of an ancient ocean?
Oehler, Dorothy Z; Allen, Carlton C
2012-06-01
This paper presents the hypothesis that the well-known giant polygons and bright mounds of the martian lowlands may be related to a common process-a process of fluid expulsion that results from burial of fine-grained sediments beneath a body of water. Specifically, we hypothesize that giant polygons and mounds in Chryse and Acidalia Planitiae are analogous to kilometer-scale polygons and mud volcanoes in terrestrial, marine basins and that the co-occurrence of masses of these features in Chryse and Acidalia may be the signature of sedimentary processes in an ancient martian ocean. We base this hypothesis on recent data from both Earth and Mars. On Earth, 3-D seismic data illustrate kilometer-scale polygons that may be analogous to the giant polygons on Mars. The terrestrial polygons form in fine-grained sediments that have been deposited and buried in passive-margin, marine settings. These polygons are thought to result from compaction/dewatering, and they are commonly associated with fluid expulsion features, such as mud volcanoes. On Mars, in Chryse and Acidalia Planitiae, orbital data demonstrate that giant polygons and mounds have overlapping spatial distributions. There, each set of features occurs within a geological setting that is seemingly analogous to that of the terrestrial, kilometer-scale polygons (broad basin of deposition, predicted fine-grained sediments, and lack of significant horizontal stress). Regionally, the martian polygons and mounds both show a correlation to elevation, as if their formation were related to past water levels. Although these observations are based on older data with incomplete coverage, a similar correlation to elevation has been established in one local area studied in detail with newer higher-resolution data. Further mapping with the latest data sets should more clearly elucidate the relationship(s) of the polygons and mounds to elevation over the entire Chryse-Acidalia region and thereby provide more insight into this
Energy Technology Data Exchange (ETDEWEB)
Fajeau, M; Nguyen, L T; Saunier, J [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)
1966-09-01
This code handles the following problems: -1) Analysis of thermal experiments on a water loop at high or low pressure; steady state or transient behavior; -2) Analysis of thermal and hydrodynamic behavior of water-cooled and moderated reactors, at either high or low pressure, with boiling permitted; fuel elements are assumed to be flat plates: - Flowrate in parallel channels coupled or not by conduction across plates, with conditions of pressure drops or flowrate, variable or not with respect to time is given; the power can be coupled to reactor kinetics calculation or supplied by the code user. The code, containing a schematic representation of safety rod behavior, is a one dimensional, multi-channel code, and has as its complement (FLID), a one-channel, two-dimensional code. (authors) [French] Ce code permet de traiter les problemes ci-dessous: 1. Depouillement d'essais thermiques sur boucle a eau, haute ou basse pression, en regime permanent ou transitoire; 2. Etudes thermiques et hydrauliques de reacteurs a eau, a plaques, a haute ou basse pression, ebullition permise: - repartition entre canaux paralleles, couples on non par conduction a travers plaques, pour des conditions de debit ou de pertes de charge imposees, variables ou non dans le temps; - la puissance peut etre couplee a la neutronique et une representation schematique des actions de securite est prevue. Ce code (Cactus) a une dimension d'espace et plusieurs canaux, a pour complement Flid qui traite l'etude d'un seul canal a deux dimensions. (auteurs)
Directory of Open Access Journals (Sweden)
Eliana eGaitan-Solis
2015-07-01
Full Text Available Zinc deficiency in humans is a serious problem worldwide with an estimated one third of populations at risk for insufficient zinc in diet which leads to impairment of cognitive abilities and immune system function. The goal of this research was to increase the bioavailable zinc in the edible portion of cassava roots to improve the overall zinc nutrition of populations that rely on cassava as a dietary staple. To increase zinc concentrations, two A. thaliana genes coding for ZIP1 and MTP1 were overexpressed with a tuber-specific or constitutive promoter. Eighteen transgenic events from four constructs, out of a total of 73 events generated, showed significantly higher zinc concentrations in the edible portion of the storage root compared to the non-transgenic controls. The zinc content in the transgenic lines ranged from 4 - 73 mg/Kg Dry Weight (DW as compared to the non-transgenic control which contained 8 mg/Kg. Striking changes in whole plant phenotype such as smaller plant size and chlorotic leaves were observed in transgenic lines that over accumulated zinc. In a confined field trial five transgenic events grown for 12 months showed a range of zinc concentrations from 18 – 217 mg/Kg DW. Although the overexpression of zinc transporters was successful in increasing the zinc concentrations in 25% of the transgenic lines generated, it also resulted in a decrease in plant and tuber size and overall yield due to what appears to be zinc deficiency in the aerial parts of the plant.
A fast ergodic algorithm for generating ensembles of equilateral random polygons
Varela, R.; Hinson, K.; Arsuaga, J.; Diao, Y.
2009-03-01
Knotted structures are commonly found in circular DNA and along the backbone of certain proteins. In order to properly estimate properties of these three-dimensional structures it is often necessary to generate large ensembles of simulated closed chains (i.e. polygons) of equal edge lengths (such polygons are called equilateral random polygons). However finding efficient algorithms that properly sample the space of equilateral random polygons is a difficult problem. Currently there are no proven algorithms that generate equilateral random polygons with its theoretical distribution. In this paper we propose a method that generates equilateral random polygons in a 'step-wise uniform' way. We prove that this method is ergodic in the sense that any given equilateral random polygon can be generated by this method and we show that the time needed to generate an equilateral random polygon of length n is linear in terms of n. These two properties make this algorithm a big improvement over the existing generating methods. Detailed numerical comparisons of our algorithm with other widely used algorithms are provided.
Development of polygon elements based on the scaled boundary finite element method
International Nuclear Information System (INIS)
Chiong, Irene; Song Chongmin
2010-01-01
We aim to extend the scaled boundary finite element method to construct conforming polygon elements. The development of the polygonal finite element is highly anticipated in computational mechanics as greater flexibility and accuracy can be achieved using these elements. The scaled boundary polygonal finite element will enable new developments in mesh generation, better accuracy from a higher order approximation and better transition elements in finite element meshes. Polygon elements of arbitrary number of edges and order have been developed successfully. The edges of an element are discretised with line elements. The displacement solution of the scaled boundary finite element method is used in the development of shape functions. They are shown to be smooth and continuous within the element, and satisfy compatibility and completeness requirements. Furthermore, eigenvalue decomposition has been used to depict element modes and outcomes indicate the ability of the scaled boundary polygonal element to express rigid body and constant strain modes. Numerical tests are presented; the patch test is passed and constant strain modes verified. Accuracy and convergence of the method are also presented and the performance of the scaled boundary polygonal finite element is verified on Cook's swept panel problem. Results show that the scaled boundary polygonal finite element method outperforms a traditional mesh and accuracy and convergence are achieved from fewer nodes. The proposed method is also shown to be truly flexible, and applies to arbitrary n-gons formed of irregular and non-convex polygons.
System and method for the adaptive mapping of matrix data to sets of polygons
Burdon, David (Inventor)
2003-01-01
A system and method for converting bitmapped data, for example, weather data or thermal imaging data, to polygons is disclosed. The conversion of the data into polygons creates smaller data files. The invention is adaptive in that it allows for a variable degree of fidelity of the polygons. Matrix data is obtained. A color value is obtained. The color value is a variable used in the creation of the polygons. A list of cells to check is determined based on the color value. The list of cells to check is examined in order to determine a boundary list. The boundary list is then examined to determine vertices. The determination of the vertices is based on a prescribed maximum distance. When drawn, the ordered list of vertices create polygons which depict the cell data. The data files which include the vertices for the polygons are much smaller than the corresponding cell data files. The fidelity of the polygon representation can be adjusted by repeating the logic with varying fidelity values to achieve a given maximum file size or a maximum number of vertices per polygon.
Decompositions, partitions, and coverings with convex polygons and pseudo-triangles
Aichholzer, O.; Huemer, C.; Kappes, S.; Speckmann, B.; Tóth, Cs.D.
2007-01-01
We propose a novel subdivision of the plane that consists of both convex polygons and pseudo-triangles. This pseudo-convex decomposition is significantly sparser than either convex decompositions or pseudo-triangulations for planar point sets and simple polygons. We also introduce pseudo-convex
Origin of the Polygons and Underground Structures in Western Utopia Planitia on Mars
Yoshikawa, K.
2002-01-01
The area of lower albedo (Hvm) has a higher density of polygonal patterns. These patterns potentially suggest that 1) the polygonal pattern is caused primarily by ground heaving and collapsing, 2) lower albedo materials had higher tensile strength. Additional information is contained in the original extended abstract.
Analysis of the Misconceptions of 7th Grade Students on Polygons and Specific Quadrilaterals
Ozkan, Mustafa; Bal, Ayten Pinar
2017-01-01
Purpose: This study will find out student misconceptions about geometrical figures, particularly polygons and quadrilaterals. Thus, it will offer insights into teaching these concepts. The objective of this study, the question of "What are the misconceptions of seventh grade students on polygons and quadrilaterals?" constitutes the…
International Nuclear Information System (INIS)
Yu Yunhan; Xia Yan; Liu Yaqiang; Wang Shi; Ma Tianyu; Chen Jing; Hong Baoyu
2013-01-01
To achieve a maximum compression of system matrix in positron emission tomography (PET) image reconstruction, we proposed a polygonal image pixel division strategy in accordance with rotationally symmetric PET geometry. Geometrical definition and indexing rule for polygonal pixels were established. Image conversion from polygonal pixel structure to conventional rectangular pixel structure was implemented using a conversion matrix. A set of test images were analytically defined in polygonal pixel structure, converted to conventional rectangular pixel based images, and correctly displayed which verified the correctness of the image definition, conversion description and conversion of polygonal pixel structure. A compressed system matrix for PET image recon was generated by tap model and tested by forward-projecting three different distributions of radioactive sources to the sinogram domain and comparing them with theoretical predictions. On a practical small animal PET scanner, a compress ratio of 12.6:1 of the system matrix size was achieved with the polygonal pixel structure, comparing with the conventional rectangular pixel based tap-mode one. OS-EM iterative image reconstruction algorithms with the polygonal and conventional Cartesian pixel grid were developed. A hot rod phantom was detected and reconstructed based on these two grids with reasonable time cost. Image resolution of reconstructed images was both 1.35 mm. We conclude that it is feasible to reconstruct and display images in a polygonal image pixel structure based on a compressed system matrix in PET image reconstruction. (authors)
Origami tubes with reconfigurable polygonal cross-sections.
Filipov, E T; Paulino, G H; Tachi, T
2016-01-01
Thin sheets can be assembled into origami tubes to create a variety of deployable, reconfigurable and mechanistically unique three-dimensional structures. We introduce and explore origami tubes with polygonal, translational symmetric cross-sections that can reconfigure into numerous geometries. The tubular structures satisfy the mathematical definitions for flat and rigid foldability, meaning that they can fully unfold from a flattened state with deformations occurring only at the fold lines. The tubes do not need to be straight and can be constructed to follow a non-linear curved line when deployed. The cross-section and kinematics of the tubular structures can be reprogrammed by changing the direction of folding at some folds. We discuss the variety of tubular structures that can be conceived and we show limitations that govern the geometric design. We quantify the global stiffness of the origami tubes through eigenvalue and structural analyses and highlight the mechanical characteristics of these systems. The two-scale nature of this work indicates that, from a local viewpoint, the cross-sections of the polygonal tubes are reconfigurable while, from a global viewpoint, deployable tubes of desired shapes are achieved. This class of tubes has potential applications ranging from pipes and micro-robotics to deployable architecture in buildings.
Origami tubes with reconfigurable polygonal cross-sections
Filipov, E. T.; Paulino, G. H.; Tachi, T.
2016-01-01
Thin sheets can be assembled into origami tubes to create a variety of deployable, reconfigurable and mechanistically unique three-dimensional structures. We introduce and explore origami tubes with polygonal, translational symmetric cross-sections that can reconfigure into numerous geometries. The tubular structures satisfy the mathematical definitions for flat and rigid foldability, meaning that they can fully unfold from a flattened state with deformations occurring only at the fold lines. The tubes do not need to be straight and can be constructed to follow a non-linear curved line when deployed. The cross-section and kinematics of the tubular structures can be reprogrammed by changing the direction of folding at some folds. We discuss the variety of tubular structures that can be conceived and we show limitations that govern the geometric design. We quantify the global stiffness of the origami tubes through eigenvalue and structural analyses and highlight the mechanical characteristics of these systems. The two-scale nature of this work indicates that, from a local viewpoint, the cross-sections of the polygonal tubes are reconfigurable while, from a global viewpoint, deployable tubes of desired shapes are achieved. This class of tubes has potential applications ranging from pipes and micro-robotics to deployable architecture in buildings. PMID:26997894
Transit Traffic Analysis Zone Delineating Method Based on Thiessen Polygon
Directory of Open Access Journals (Sweden)
Shuwei Wang
2014-04-01
Full Text Available A green transportation system composed of transit, busses and bicycles could be a significant in alleviating traffic congestion. However, the inaccuracy of current transit ridership forecasting methods is imposing a negative impact on the development of urban transit systems. Traffic Analysis Zone (TAZ delineating is a fundamental and essential step in ridership forecasting, existing delineating method in four-step models have some problems in reflecting the travel characteristics of urban transit. This paper aims to come up with a Transit Traffic Analysis Zone delineation method as supplement of traditional TAZs in transit service analysis. The deficiencies of current TAZ delineating methods were analyzed, and the requirements of Transit Traffic Analysis Zone (TTAZ were summarized. Considering these requirements, Thiessen Polygon was introduced into TTAZ delineating. In order to validate its feasibility, Beijing was then taken as an example to delineate TTAZs, followed by a spatial analysis of office buildings within a TTAZ and transit station departure passengers. Analysis result shows that the TTAZs based on Thiessen polygon could reflect the transit travel characteristic and is of in-depth research value.
Polygonal patterned peatlands of the White Sea islands
Kutenkov, S. A.; Kozhin, M. N.; Golovina, E. O.; Kopeina, E. I.; Stoikina, N. V.
2018-03-01
The summits and slopes of some islands along the northeastern and northern coasts of the White Sea are covered with dried out peatlands. The thickness of the peat deposit is 30–80 cm and it is separated by troughs into gently sloping polygonal peat blocks up to 20 m2 in size. On some northern islands the peat blocks have permafrost cores. The main components of the dried out peatlands vegetation are dwarf shrubs and lichens. The peat stratigraphy reveals two stages of peatland development. On the first stage, the islands were covered with wet cottongrass carpets, which repeated the convex relief shape. On the second stage, they were occupied by the xeromorphic vegetation. We suggest that these polygonal patterned peatlands are the remnants of blanket bogs, the formation of which assumes the conditions of a much more humid climate in the historical past. The time of their active development was calculated according to the White Sea level changes and radiocarbon dates from 1000–4000 BP.
Carvalho, Sandra; da Silva, Rosa Barreira; Shawki, Ali; Castro, Helena; Lamy, Márcia; Eide, David; Costa, Vítor; Mackenzie, Bryan; Tomás, Ana M.
2016-01-01
Summary Cellular zinc homeostasis ensures that the intracellular concentration of this element is kept within limits that enable its participation in critical physiological processes without exerting toxic effects. We report here the identification and characterization of the first mediator of zinc homeostasis in Leishmania infantum, LiZIP3, a member of the ZIP family of divalent metal-ion transporters. The zinc transporter activity of LiZIP3 was first disclosed by its capacity to rescue the growth of Saccharomyces cerevisiae strains deficient in zinc acquisition. Subsequent expression of LiZIP3 in Xenopus laevis oocytes was shown to stimulate the uptake of a broad range of metal ions, among which Zn2+ was the preferred LiZIP3 substrate (K0.5 ≈ 0.1 μM). Evidence that LiZIP3 functions as a zinc importer in L. infantum came from the observations that the protein locates to the cell membrane and that its overexpression leads to augmented zinc internalization. Importantly, expression and cell-surface location of LiZIP3 are lost when parasites face high zinc bioavailability. LiZIP3 decline in response to zinc is regulated at the mRNA level in a process involving (a) short-lived protein(s). Collectively, our data reveal that LiZIP3 enables L. infantum to acquire zinc in a highly regulated manner, hence contributing to zinc homeostasis. PMID:25644708
Brooker, L. M.; Balme, M. R.; Conway, S. J.; Hagermann, A.; Barrett, A. M.; Collins, G. S.; Soare, R. J.
2018-03-01
Polygonal networks of patterned ground are a common feature in cold-climate environments. They can form through the thermal contraction of ice-cemented sediment (i.e. formed from fractures), or the freezing and thawing of ground ice (i.e. formed by patterns of clasts, or ground deformation). The characteristics of these landforms provide information about environmental conditions. Analogous polygonal forms have been observed on Mars leading to inferences about environmental conditions. We have identified clastic polygonal features located around Lyot crater, Mars (50°N, 30°E). These polygons are unusually large (>100 m diameter) compared to terrestrial clastic polygons, and contain very large clasts, some of which are up to 15 metres in diameter. The polygons are distributed in a wide arc around the eastern side of Lyot crater, at a consistent distance from the crater rim. Using high-resolution imaging data, we digitised these features to extract morphological information. These data are compared to existing terrestrial and Martian polygon data to look for similarities and differences and to inform hypotheses concerning possible formation mechanisms. Our results show the clastic polygons do not have any morphometric features that indicate they are similar to terrestrial sorted, clastic polygons formed by freeze-thaw processes. They are too large, do not show the expected variation in form with slope, and have clasts that do not scale in size with polygon diameter. However, the clastic networks are similar in network morphology to thermal contraction cracks, and there is a potential direct Martian analogue in a sub-type of thermal contraction polygons located in Utopia Planitia. Based upon our observations, we reject the hypothesis that polygons located around Lyot formed as freeze-thaw polygons and instead an alternative mechanism is put forward: they result from the infilling of earlier thermal contraction cracks by wind-blown material, which then became
A Polygon and Point-Based Approach to Matching Geospatial Features
Directory of Open Access Journals (Sweden)
Juan J. Ruiz-Lendínez
2017-12-01
Full Text Available A methodology for matching bidimensional entities is presented in this paper. The matching is proposed for both area and point features extracted from geographical databases. The procedure used to obtain homologous entities is achieved in a two-step process: The first matching, polygon to polygon matching (inter-element matching, is obtained by means of a genetic algorithm that allows the classifying of area features from two geographical databases. After this, we apply a point to point matching (intra-element matching based on the comparison of changes in their turning functions. This study shows that genetic algorithms are suitable for matching polygon features even if these features are quite different. Our results show up to 40% of matched polygons with differences in geometrical attributes. With regards to point matching, the vertex from homologous polygons, the function and threshold values proposed in this paper show a useful method for obtaining precise vertex matching.
The average inter-crossing number of equilateral random walks and polygons
International Nuclear Information System (INIS)
Diao, Y; Dobay, A; Stasiak, A
2005-01-01
In this paper, we study the average inter-crossing number between two random walks and two random polygons in the three-dimensional space. The random walks and polygons in this paper are the so-called equilateral random walks and polygons in which each segment of the walk or polygon is of unit length. We show that the mean average inter-crossing number ICN between two equilateral random walks of the same length n is approximately linear in terms of n and we were able to determine the prefactor of the linear term, which is a = 3ln2/8 ∼ 0.2599. In the case of two random polygons of length n, the mean average inter-crossing number ICN is also linear, but the prefactor of the linear term is different from that of the random walks. These approximations apply when the starting points of the random walks and polygons are of a distance ρ apart and ρ is small compared to n. We propose a fitting model that would capture the theoretical asymptotic behaviour of the mean average ICN for large values of ρ. Our simulation result shows that the model in fact works very well for the entire range of ρ. We also study the mean ICN between two equilateral random walks and polygons of different lengths. An interesting result is that even if one random walk (polygon) has a fixed length, the mean average ICN between the two random walks (polygons) would still approach infinity if the length of the other random walk (polygon) approached infinity. The data provided by our simulations match our theoretical predictions very well
Deformations of polyhedra and polygons by the unitary group
Energy Technology Data Exchange (ETDEWEB)
Livine, Etera R. [Laboratoire de Physique, ENS Lyon, CNRS-UMR 5672, 46 Allée d' Italie, Lyon 69007, France and Perimeter Institute, 31 Caroline St N, Waterloo, Ontario N2L 2Y5 (Canada)
2013-12-15
We introduce the set of framed (convex) polyhedra with N faces as the symplectic quotient C{sup 2N}//SU(2). A framed polyhedron is then parametrized by N spinors living in C{sup 2} satisfying suitable closure constraints and defines a usual convex polyhedron plus extra U(1) phases attached to each face. We show that there is a natural action of the unitary group U(N) on this phase space, which changes the shape of faces and allows to map any (framed) polyhedron onto any other with the same total (boundary) area. This identifies the space of framed polyhedra to the Grassmannian space U(N)/ (SU(2)×U(N−2)). We show how to write averages of geometrical observables (polynomials in the faces' area and the angles between them) over the ensemble of polyhedra (distributed uniformly with respect to the Haar measure on U(N)) as polynomial integrals over the unitary group and we provide a few methods to compute these integrals systematically. We also use the Itzykson-Zuber formula from matrix models as the generating function for these averages and correlations. In the quantum case, a canonical quantization of the framed polyhedron phase space leads to the Hilbert space of SU(2) intertwiners (or, in other words, SU(2)-invariant states in tensor products of irreducible representations). The total boundary area as well as the individual face areas are quantized as half-integers (spins), and the Hilbert spaces for fixed total area form irreducible representations of U(N). We define semi-classical coherent intertwiner states peaked on classical framed polyhedra and transforming consistently under U(N) transformations. And we show how the U(N) character formula for unitary transformations is to be considered as an extension of the Itzykson-Zuber to the quantum level and generates the traces of all polynomial observables over the Hilbert space of intertwiners. We finally apply the same formalism to two dimensions and show that classical (convex) polygons can be described in
Capsella rubella TGA4, a bZIP transcription factor, causes delayed flowering in Arabidopsis thaliana
Directory of Open Access Journals (Sweden)
Li Maofu
2016-01-01
Full Text Available Flowering time is usually regulated by many environmental factors and endogenous signals. TGA family members are bZIP transcription factors that bind to the octopine synthase element, which has been closely linked to defense/stress responses. Most TGA factors interact with non-expressor of PR1 (NPR1 and plant defense responses are strengthened by this interaction. TGA1and TGA4factors bind to NPR1 only in salicylic acid (SA-induced leaves, suggesting that TGA4 has another function during plant development. Here, we isolated a bZIP transcription factor gene, TGA4, from Capsella rubella. TGA4transcripts were detected in most tissues, with high expression in leaves, low expression in stems and flowering buds, and undetectable in siliques. CruTGA4was over expressed in Arabidopsis thaliana wild typeCol-0 plants. Flowering time and total leaf number in the transgenic plants showed that overexpression of CruTGA4could delay flowering in A. thaliana. Our findings suggest that TGA4 may act as flowering regulator that controls plant flowering.
Isolation and expression analysis of four HD-ZIP III family genes targeted by microRNA166 in peach.
Zhang, C H; Zhang, B B; Ma, R J; Yu, M L; Guo, S L; Guo, L
2015-10-30
MicroRNA166 (miR166) is known to have highly conserved targets that encode proteins of the class III homeodomain-leucine zipper (HD-ZIP III) family, in a broad range of plant species. To further understand the relationship between HD-ZIP III genes and miR166, four HD-ZIP III family genes (PpHB14, PpHB15, PpHB8, and PpREV) were isolated from peach (Prunus persica) tissue and characterized. Spatio-temporal expression profiles of the genes were analyzed. Genes of the peach HD-ZIP III family were predicted to encode five conserved domains. Deduced amino acid sequences and tertiary structures of the four peach HD-ZIP III genes were highly conserved, with corresponding genes in Arabidopsis thaliana. The expression level of four targets displayed the opposite trend to that of miR166 throughout fruit development, with the exception of PpHB14 from 35 to 55 days after full bloom (DAFB). This finding indicates that miR166 may negatively regulate its four targets throughout fruit development. As for leaf and phloem, the same trend in expression level was observed between four targets and miR166 from 75 to 105 DAFB. However, the opposite trend was observed for the transcript level between four targets and miR166 from 35 to 55 DAFB. miRNA166 may negatively regulate four targets in some but not all developmental stages for a given tissue. The four genes studied were observed to have, exactly or generally, the same change tendency as individual tissue development, a finding that suggests genes of the HD-ZIP III family in peach may have complementary or cooperative functions in various tissues.
International Nuclear Information System (INIS)
Pratt, W.T.; Ludewig, H.; Bari, R.A.; Meyer, J.F.
1983-01-01
An evaluation of core meltdown accidents in the Z/IP facilities has been performed. Containment event trees have been developed to relate the progression of a given accident to various potential containment building failure modes. An extensive uncertainty analysis related to core melt phenomenology has been performed. A major conclusion of the study is that large variations in parameters associated with major phenomenological uncertainties have a relatively minor impact on risk when external initiators are considered. This is due to the inherent capability fo the Z/IP containment buildings to contain a wide range of core meltdown accidents. 12 references, 2 tables
PATTERN CLASSIFICATION APPROACHES TO MATCHING BUILDING POLYGONS AT MULTIPLE SCALES
Directory of Open Access Journals (Sweden)
X. Zhang
2012-07-01
Full Text Available Matching of building polygons with different levels of detail is crucial in the maintenance and quality assessment of multi-representation databases. Two general problems need to be addressed in the matching process: (1 Which criteria are suitable? (2 How to effectively combine different criteria to make decisions? This paper mainly focuses on the second issue and views data matching as a supervised pattern classification. Several classifiers (i.e. decision trees, Naive Bayes and support vector machines are evaluated for the matching task. Four criteria (i.e. position, size, shape and orientation are used to extract information for these classifiers. Evidence shows that these classifiers outperformed the weighted average approach.
Treks into intuitive geometry the world of polygons and polyhedra
Akiyama, Jin
2015-01-01
This book is written in a style that uncovers the mathematical theories buried in our everyday lives such as examples from patterns that appear in nature, art, and traditional crafts, and in mathematical mechanisms in techniques used by architects. The authors believe that through dialogues between students and mathematicians, readers may discover the processes by which the founders of the theories came to their various conclusions―their trials, errors, tribulations, and triumphs. The goal is for readers to refine their mathematical sense of how to find good questions and how to grapple with these problems. Another aim is to provide enjoyment in the process of applying mathematical rules to beautiful art and design by examples that highlight the wonders and mysteries from our daily lives. To fulfill these aims, this book deals with the latest unique and beautiful results in polygons and polyhedra and the dynamism of geometrical research history that can be found around us. The term "intuitive geometry" was ...
Reachability by paths of bounded curvature in a convex polygon
Ahn, Heekap; Cheong, Otfried; Matoušek, Jiřǐ; Vigneron, Antoine E.
2012-01-01
Let B be a point robot moving in the plane, whose path is constrained to forward motions with curvature at most 1, and let P be a convex polygon with n vertices. Given a starting configuration (a location and a direction of travel) for B inside P, we characterize the region of all points of P that can be reached by B, and show that it has complexity O(n). We give an O(n2) time algorithm to compute this region. We show that a point is reachable only if it can be reached by a path of type CCSCS, where C denotes a unit circle arc and S denotes a line segment. © 2011 Elsevier B.V.
Vortex breakdown in closed containers with polygonal cross sections
International Nuclear Information System (INIS)
Naumov, I. V.; Dvoynishnikov, S. V.; Kabardin, I. K.; Tsoy, M. A.
2015-01-01
The vortex breakdown bubble in the confined flow generated by a rotating lid in closed containers with polygonal cross sections was analysed both experimentally and numerically for the height/radius aspect ratio equal to 2. The stagnation point locations of the breakdown bubble emergence and the corresponding Reynolds number were determined experimentally and in addition computed numerically by STAR-CCM+ CFD software for square, pentagonal, hexagonal, and octagonal cross section configurations. The flow pattern and the velocity were observed and measured by combining the seeding particle visualization and the temporal accuracy of laser Doppler anemometry. The vortex breakdown size and position on the container axis were determined for Reynolds numbers, ranging from 1450 to 2400. The obtained results were compared with the flow structure in the closed container of cubical and cylindrical configurations. It is shown that the measured evolution of steady vortex breakdown is in close agreement with the numerical results
Convergence of Wachspress coordinates: from polygons to curved domains
Kosinka, Jiří
2014-08-08
Given a smooth, strictly convex planar domain, we investigate point-wise convergence of the sequence of Wachspress coordinates defined over finer and finer inscribed polygonal approximations of the domain. Based on a relation between the discrete Wachspress case and the limit smooth case given by the Wachspress kernel defined by Warren et al., we show that the corresponding sequences of Wachspress interpolants and mappings converge as 𝓞(h2) for a sampling step size h of the boundary curve of the domain as h → 0. Several examples are shown to numerically validate the results and to visualise the behaviour of discrete interpolants and mappings as they converge to their smooth counterparts. Empirically, the same convergence order is observed also for mean value coordinates. Moreover, our numerical tests suggest that the convergence of interpolants and mappings is uniform both in the Wachspress and mean value cases. © 2014 Springer Science+Business Media New York.
Polygons of differential equations for finding exact solutions
International Nuclear Information System (INIS)
Kudryashov, Nikolai A.; Demina, Maria V.
2007-01-01
A method for finding exact solutions of nonlinear differential equations is presented. Our method is based on the application of polygons corresponding to nonlinear differential equations. It allows one to express exact solutions of the equation studied through solutions of another equation using properties of the basic equation itself. The ideas of power geometry are used and developed. Our approach has a pictorial interpretation, which is illustrative and effective. The method can be also applied for finding transformations between solutions of differential equations. To demonstrate the method application exact solutions of several equations are found. These equations are: the Korteveg-de Vries-Burgers equation, the generalized Kuramoto-Sivashinsky equation, the fourth-order nonlinear evolution equation, the fifth-order Korteveg-de Vries equation, the fifth-order modified Korteveg-de Vries equation and the sixth-order nonlinear evolution equation describing turbulent processes. Some new exact solutions of nonlinear evolution equations are given
Convergence of Wachspress coordinates: from polygons to curved domains
Kosinka, Jiří
2014-01-01
Given a smooth, strictly convex planar domain, we investigate point-wise convergence of the sequence of Wachspress coordinates defined over finer and finer inscribed polygonal approximations of the domain. Based on a relation between the discrete Wachspress case and the limit smooth case given by the Wachspress kernel defined by Warren et al., we show that the corresponding sequences of Wachspress interpolants and mappings converge as 𝓞(h2) for a sampling step size h of the boundary curve of the domain as h → 0. Several examples are shown to numerically validate the results and to visualise the behaviour of discrete interpolants and mappings as they converge to their smooth counterparts. Empirically, the same convergence order is observed also for mean value coordinates. Moreover, our numerical tests suggest that the convergence of interpolants and mappings is uniform both in the Wachspress and mean value cases. © 2014 Springer Science+Business Media New York.
Generalized Swept Mid-structure for Polygonal Models
Martin, Tobias; Chen, Guoning; Musuvathy, Suraj; Cohen, Elaine; Hansen, Charles
2012-01-01
We introduce a novel mid-structure called the generalized swept mid-structure (GSM) of a closed polygonal shape, and a framework to compute it. The GSM contains both curve and surface elements and has consistent sheet-by-sheet topology, versus triangle-by-triangle topology produced by other mid-structure methods. To obtain this structure, a harmonic function, defined on the volume that is enclosed by the surface, is used to decompose the volume into a set of slices. A technique for computing the 1D mid-structures of these slices is introduced. The mid-structures of adjacent slices are then iteratively matched through a boundary similarity computation and triangulated to form the GSM. This structure respects the topology of the input surface model is a hybrid mid-structure representation. The construction and topology of the GSM allows for local and global simplification, used in further applications such as parameterization, volumetric mesh generation and medical applications.
Generalized Swept Mid-structure for Polygonal Models
Martin, Tobias
2012-05-01
We introduce a novel mid-structure called the generalized swept mid-structure (GSM) of a closed polygonal shape, and a framework to compute it. The GSM contains both curve and surface elements and has consistent sheet-by-sheet topology, versus triangle-by-triangle topology produced by other mid-structure methods. To obtain this structure, a harmonic function, defined on the volume that is enclosed by the surface, is used to decompose the volume into a set of slices. A technique for computing the 1D mid-structures of these slices is introduced. The mid-structures of adjacent slices are then iteratively matched through a boundary similarity computation and triangulated to form the GSM. This structure respects the topology of the input surface model is a hybrid mid-structure representation. The construction and topology of the GSM allows for local and global simplification, used in further applications such as parameterization, volumetric mesh generation and medical applications.
An electrophysiological study of the mental rotation of polygons.
Pierret, A; Peronnet, F; Thevenet, M
1994-05-09
Reaction times and event-related potentials (ERPs) were recorded during a task requiring subjects to decide whether two sequentially presented polygons had the same shape regardless of differences in orientation. Reaction times increased approximately linearly with angular departure from upright orientation, which suggests that mental rotation was involved in the comparison process. The ERPs showed, between 665 and 1055 ms, a late posterior negativity also increasing with angular disparity from upright, which we assumed to reflect mental rotation. Two other activities were exhibited, from 265 to 665 ms, which may be related either to an evaluation of the stimulus or a predetermination of its orientation, and from 1055 to 1600 ms attributed to the decision process.
Experimental investigation into the mechanism of the polygonal wear of electric locomotive wheels
Tao, Gongquan; Wang, Linfeng; Wen, Zefeng; Guan, Qinghua; Jin, Xuesong
2018-06-01
Experiments were conducted at field sites to investigate the mechanism of the polygonal wear of electric locomotive wheels. The polygonal wear rule of electric locomotive wheels was obtained. Moreover, two on-track tests have been carried out to investigate the vibration characteristics of the electric locomotive's key components. The measurement results of wheels out-of-round show that most electric locomotive wheels exhibit polygonal wear. The main centre wavelength in the 1/3 octave bands is 200 mm and/or 160 mm. The test results of vibration characteristics indicate that the dominating frequency of the vertical acceleration measured on the axle box is approximately equal to the passing frequency of a polygonal wheel, and does not vary with the locomotive speed during the acceleration course. The wheelset modal analysis using the finite element method (FEM) indicates that the first bending resonant frequency of the wheelset is quite close to the main vibration frequency of the axle box. The FEM results are verified by the experimental modal analysis of the wheelset. Moreover, different plans were designed to verify whether the braking system and the locomotive's adhesion control have significant influence on the wheel polygon or not. The test results indicate that they are not responsible for the initiation of the wheel polygon. The first bending resonance of the wheelset is easy to be excited in the locomotive operation and it is the root cause of wheel polygon with centre wavelength of 200 mm in the 1/3 octave bands.
Chen, Eryong; Zhang, Xueyan; Yang, Zhaoen; Wang, Xiaoqian; Yang, Zuoren; Zhang, Chaojun; Wu, Zhixia; Kong, Depei; Liu, Zhao; Zhao, Ge; Butt, Hamama Islam; Zhang, Xianlong; Li, Fuguang
2017-06-01
HD-ZIP IV proteins belong to the homeodomain-leucine zipper (HD-ZIP) transcription factor family and are involved in trichome development and drought stress in plants. Although some functions of the HD-ZIP IV group are well understood in Arabidopsis, little is known about their function in cotton. In this study, HD-ZIP genes were identified from three Gossypium species (G. arboreum, G. raimondii and G. hirsutum) and clustered into four families (HD-ZIP I, II, III and IV) to separate HD-ZIP IV from the other three families. Systematic analyses of phylogeny, gene structure, conserved domains, and expression profiles in different plant tissues and the expression patterns under osmotic stress in leaves were further conducted in G. arboreum. More importantly, ectopic overexpression of GaHDG11, a representative of the HD-ZIP IV family, confers enhanced osmotic tolerance in transgenic Arabidopsis plants, possibly due to elongated primary root length, lower water loss rates, high osmoprotectant proline levels, significant levels of antioxidants CAT, and/or SOD enzyme activity with reduced levels of MDA. Taken together, these observations may lay the foundation for future functional analysis of cotton HD-ZIP IV genes to unravel their biological roles in cotton.
Directory of Open Access Journals (Sweden)
Carrie A Adelman
2008-03-01
Full Text Available We have recently shown that hypomorphic Mre11 complex mouse mutants exhibit defects in the repair of meiotic double strand breaks (DSBs. This is associated with perturbation of synaptonemal complex morphogenesis, repair and regulation of crossover formation. To further assess the Mre11 complex's role in meiotic progression, we identified testis-specific NBS1-interacting proteins via two-hybrid screening in yeast. In this screen, Zip4h (Tex11, a male germ cell specific X-linked gene was isolated. Based on sequence and predicted structural similarity to the S. cerevisiae and A. thaliana Zip4 orthologs, ZIP4H appears to be the mammalian ortholog. In S. cerevisiae and A. thaliana, Zip4 is a meiosis-specific protein that regulates the level of meiotic crossovers, thus influencing homologous chromosome segregation in these organisms. As is true for hypomorphic Nbs1 (Nbs1(DeltaB/DeltaB mice, Zip4h(-/Y mutant mice were fertile. Analysis of spermatocytes revealed a delay in meiotic double strand break repair and decreased crossover formation as inferred from DMC1 and MLH1 staining patterns, respectively. Achiasmate chromosomes at the first meiotic division were also observed in Zip4h(-/Y mutants, consistent with the observed reduction in MLH1 focus formation. These results indicate that meiotic functions of Zip4 family members are conserved and support the view that the Mre11 complex and ZIP4H interact functionally during the execution of the meiotic program in mammals.
The homeodomain leucine zipper (HD-Zip) transcription factor family is one of the largest plant specific superfamilies, and includes genes with roles in modulation of plant growth and response to environmental stresses. Many HD-Zip genes are well characterized in Arabidopsis (Arabidopsis thaliana), ...
2000 Census 3-Digit ZIP Code Tabulation Areas (ZCTAs) for Luna County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
2015 Cartographic Boundary File, 5-Digit ZIP Code Tabulation Area for United States, 1:500,000
US Census Bureau, Department of Commerce — The 2015 cartographic boundary shapefiles are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File /...
2000 Census 3-Digit ZIP Code Tabulation Areas (ZCTAs) for Harding County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
2000 Census 5-Digit ZIP Code Tabulation Areas (ZCTAs) for Catron County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
2000 Census 3-Digit ZIP Code Tabulation Areas (ZCTAs) for De Baca County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
2000 Census 3-Digit ZIP Code Tabulation Areas (ZCTAs) for Roosevelt County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Current 3-Digit ZIP Code Tabulation Areas (ZCTAs) for McKinley County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
2000 Census 3-Digit ZIP Code Tabulation Areas (ZCTAs) for Santa Fe County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
2000 Census 3-Digit ZIP Code Tabulation Areas (ZCTAs) for Colfax County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
2000 Census 5-Digit ZIP Code Tabulation Areas (ZCTAs) for Union County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Current 5-Digit ZIP Code Tabulation Areas (ZCTAs) for McKinley County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
2000 Census 5-Digit ZIP Code Tabulation Areas (ZCTAs) for Taos County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
2000 Census 3-Digit ZIP Code Tabulation Areas (ZCTAs) for Quay County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
2000 Census 3-Digit ZIP Code Tabulation Areas (ZCTAs) for McKinley County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
2000 Census 5-Digit ZIP Code Tabulation Areas (ZCTAs) for Eddy County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
2014 Cartographic Boundary File, 5-Digit ZIP Code Tabulation Area for United States, 1:500,000
US Census Bureau, Department of Commerce — The 2014 cartographic boundary KMLs are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File / Topologically...
2014 Cartographic Boundary File, 5-Digit ZIP Code Tabulation Area for United States, 1:500,000
US Census Bureau, Department of Commerce — The 2014 cartographic boundary shapefiles are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File /...
2000 Census 5-Digit ZIP Code Tabulation Areas (ZCTAs) for McKinley County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
Current 5-Digit ZIP Code Tabulation Areas (ZCTAs) for San Juan County, New Mexico, 2006se TIGER
Earth Data Analysis Center, University of New Mexico — The 2006 Second Edition TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER database. The geographic coverage...
A Polygon Model for Wireless Sensor Network Deployment with Directional Sensing Areas
Wu, Chun-Hsien; Chung, Yeh-Ching
2009-01-01
The modeling of the sensing area of a sensor node is essential for the deployment algorithm of wireless sensor networks (WSNs). In this paper, a polygon model is proposed for the sensor node with directional sensing area. In addition, a WSN deployment algorithm is presented with topology control and scoring mechanisms to maintain network connectivity and improve sensing coverage rate. To evaluate the proposed polygon model and WSN deployment algorithm, a simulation is conducted. The simulation results show that the proposed polygon model outperforms the existed disk model and circular sector model in terms of the maximum sensing coverage rate. PMID:22303159
On reconstruction of an unknown polygonal cavity in a linearized elasticity with one measurement
International Nuclear Information System (INIS)
Ikehata, M; Itou, H
2011-01-01
In this paper we consider a reconstruction problem of an unknown polygonal cavity in a linearized elastic body. For this problem, an extraction formula of the convex hull of the unknown polygonal cavity is established by means of the enclosure method introduced by Ikehata. The advantages of our method are that it needs only a single set of boundary data and we do not require any a priori assumptions for the unknown polygonal cavity and any constraints on boundary data. The theoretical formula may have possibility of application in nondestructive evaluation.
The generation algorithm of arbitrary polygon animation based on dynamic correction
Directory of Open Access Journals (Sweden)
Hou Ya Wei
2016-01-01
Full Text Available This paper, based on the key-frame polygon sequence, proposes a method that makes use of dynamic correction to develop continuous animation. Firstly we use quadratic Bezier curve to interpolate the corresponding sides vector of polygon sequence consecutive frame and realize the continuity of animation sequences. And then, according to Bezier curve characteristic, we conduct dynamic regulation to interpolation parameters and implement the changing smoothness. Meanwhile, we take use of Lagrange Multiplier Method to correct the polygon and close it. Finally, we provide the concrete algorithm flow and present numerical experiment results. The experiment results show that the algorithm acquires excellent effect.
Directory of Open Access Journals (Sweden)
Carlos Mario Escobar Callejas
2011-12-01
Full Text Available En el presente artículo de investigación se caracteriza el tipo de bifurcación de Hopf que se presenta en el fenómeno de la bifurcación de zip para un sistema tridimensional no lineal de ecuaciones diferenciales que satisface las condiciones planteadas por Butler y Farkas, las cuales modelan la competición de dos especies predadoras por una presa singular que se regenera. Se demuestra que en todas las variedades bidimensionales invariantes del sistema considerado se desarrolla una bifurcación de Hopf supercrítica lo cual es una extensión de algunos resultados sobre el tipo de bifurcación de Hopf que se forma en el fenómeno de la bifurcación de zip en sistema con respuesta funcional del predador del tipo Holling II, [1].This research article characterizes the type of Hopf bifurcation occurring in the Zip bifurcation phenomenon for a non-linear 3D system of differential equations which meets the conditions stated by Butler and Farkas to model competition of two predators struggling for a prey. It is shown that a supercritical Hopf bifurcation is developed in all invariant two-dimensional varieties of the system considered, which is an extension of some results about the kind of Hopf bifurcation which is formed in the Zip bifurcation phenomenon in a system with functional response of the Holling-type predator.
Development of a pregnant woman phantom using polygonal mesh, for dosimetric evaluations
Energy Technology Data Exchange (ETDEWEB)
Cabral, Manuela O.M.; Vieira, Jose W., E-mail: manuela.omc@gmail.com [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear; Leal Neto, Viriato, E-mail: viriatoleal@yahoo.com.br [Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco (IFPE), Recife, PE (Brazil); Lima, Fernando R.A., E-mail: falima@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)
2014-07-01
Due to the embryo/fetus radiosensitivity the accurate estimation of the absorbed dose distribution in the abdominal area is an additional problem caused by the exposure of pregnant women to ionizing radiation in medical applications. This paper reports the construction and insertion of a fetal representation in a female geometry by means of 3D modeling techniques. In order to characterize an ECM the Grupo de Dosimetria Numerica (GDN) is using, mainly, simulators emitting gamma sources and voxel phantoms coupled to a MC code. The phantoms are predominantly constructed from stacks of magnetic resonance images (MRI), computed tomography (CT) (obtained from scans of real patients) or from 3D modeling techniques. Due to the difficulty of obtaining medical images of pregnant women, 3D objects in several formats (.obj, .max, .blend, etc.) were acquired for anatomical representation of a non-pregnant adult. To construct a fetal representation, the 3D modeling technique called Poly Modeling (polygon mesh) was used inside of the software Autodesk 3ds Max 2014 (free student version). Information about the radiosensibility of organs included in the abdominal area will be used to fit and use the pregnant phantom in numerical dosimetry. For this, the phantom will be voxelized and the masses of organs of interest will be adjusted according to data provided by International Commission on Radiological Protection (ICRP). Finally, the phantom will be coupled to a MC code creating a MCE that will serve as base for the construction of several other models involving pregnant women submitted to ionizing radiation. (author)
Development of a pregnant woman phantom using polygonal mesh, for dosimetric evaluations
International Nuclear Information System (INIS)
Cabral, Manuela O.M.; Vieira, Jose W.; Lima, Fernando R.A.
2014-01-01
Due to the embryo/fetus radiosensitivity the accurate estimation of the absorbed dose distribution in the abdominal area is an additional problem caused by the exposure of pregnant women to ionizing radiation in medical applications. This paper reports the construction and insertion of a fetal representation in a female geometry by means of 3D modeling techniques. In order to characterize an ECM the Grupo de Dosimetria Numerica (GDN) is using, mainly, simulators emitting gamma sources and voxel phantoms coupled to a MC code. The phantoms are predominantly constructed from stacks of magnetic resonance images (MRI), computed tomography (CT) (obtained from scans of real patients) or from 3D modeling techniques. Due to the difficulty of obtaining medical images of pregnant women, 3D objects in several formats (.obj, .max, .blend, etc.) were acquired for anatomical representation of a non-pregnant adult. To construct a fetal representation, the 3D modeling technique called Poly Modeling (polygon mesh) was used inside of the software Autodesk 3ds Max 2014 (free student version). Information about the radiosensibility of organs included in the abdominal area will be used to fit and use the pregnant phantom in numerical dosimetry. For this, the phantom will be voxelized and the masses of organs of interest will be adjusted according to data provided by International Commission on Radiological Protection (ICRP). Finally, the phantom will be coupled to a MC code creating a MCE that will serve as base for the construction of several other models involving pregnant women submitted to ionizing radiation. (author)
Das, Rahul K; Crick, Scott L; Pappu, Rohit V
2012-02-17
Basic region leucine zippers (bZIPs) are modular transcription factors that play key roles in eukaryotic gene regulation. The basic regions of bZIPs (bZIP-bRs) are necessary and sufficient for DNA binding and specificity. Bioinformatic predictions and spectroscopic studies suggest that unbound monomeric bZIP-bRs are uniformly disordered as isolated domains. Here, we test this assumption through a comparative characterization of conformational ensembles for 15 different bZIP-bRs using a combination of atomistic simulations and circular dichroism measurements. We find that bZIP-bRs have quantifiable preferences for α-helical conformations in their unbound monomeric forms. This helicity varies from one bZIP-bR to another despite a significant sequence similarity of the DNA binding motifs (DBMs). Our analysis reveals that intramolecular interactions between DBMs and eight-residue segments directly N-terminal to DBMs are the primary modulators of bZIP-bR helicities. We test the accuracy of this inference by designing chimeras of bZIP-bRs to have either increased or decreased overall helicities. Our results yield quantitative insights regarding the relationship between sequence and the degree of intrinsic disorder within bZIP-bRs, and might have general implications for other intrinsically disordered proteins. Understanding how natural sequence variations lead to modulation of disorder is likely to be important for understanding the evolution of specificity in molecular recognition through intrinsically disordered regions (IDRs). Copyright © 2011 Elsevier Ltd. All rights reserved.
Directory of Open Access Journals (Sweden)
Gainza-Cortés Felipe
2012-07-01
Full Text Available Abstract Background Zinc (Zn deficiency is one of the most widespread mineral nutritional problems that affect normal development in plants. Because Zn cannot passively diffuse across cell membranes, it must be transported into intracellular compartments for all biological processes where Zn is required. Several members of the Zinc-regulated transporters, Iron-regulated transporter-like Protein (ZIP gene family have been characterized in plants, and have shown to be involved in metal uptake and transport. This study describes the first putative Zn transporter in grapevine. Unravelling its function may explain an important symptom of Zn deficiency in grapevines, which is the production of clusters with fewer and usually smaller berries than normal. Results We identified and characterized a putative Zn transporter from berries of Vitis vinifera L., named VvZIP3. Compared to other members of the ZIP family identified in the Vitis vinifera L. genome, VvZIP3 is mainly expressed in reproductive tissue - specifically in developing flowers - which correlates with the high Zn accumulation in these organs. Contrary to this, the low expression of VvZIP3 in parthenocarpic berries shows a relationship with the lower Zn accumulation in this tissue than in normal seeded berries where its expression is induced by Zn. The predicted protein sequence indicates strong similarity with several members of the ZIP family from Arabidopsis thaliana and other species. Moreover, VvZIP3 complemented the growth defect of a yeast Zn-uptake mutant, ZHY3, and is localized in the plasma membrane of plant cells, suggesting that VvZIP3 has the function of a Zn uptake transporter. Conclusions Our results suggest that VvZIP3 encodes a putative plasma membrane Zn transporter protein member of the ZIP gene family that might play a role in Zn uptake and distribution during the early reproductive development in Vitis vinifera L., indicating that the availability of this micronutrient
Nagashima, Yukihiro
2011-07-01
IRE1 plays an essential role in the endoplasmic reticulum (ER) stress response in yeast and mammals. We found that a double mutant of Arabidopsis IRE1A and IRE1B (ire1a/ire1b) is more sensitive to the ER stress inducer tunicamycin than the wild-type. Transcriptome analysis revealed that genes whose induction was reduced in ire1a/ire1b largely overlapped those in the bzip60 mutant. We observed that the active form of bZIP60 protein detected in the wild-type was missing in ire1a/ire1b. We further demonstrated that bZIP60 mRNA is spliced by ER stress, removing 23 ribonucleotides and therefore causing a frameshift that replaces the C-terminal region of bZIP60 including the transmembrane domain (TMD) with a shorter region without a TMD. This splicing was detected in ire1a and ire1b single mutants, but not in the ire1a/ire1b double mutant. We conclude that IRE1A and IRE1B catalyse unconventional splicing of bZIP60 mRNA to produce the active transcription factor.
Nagashima, Yukihiro; Mishiba, Kei-ichiro; Suzuki, Eiji; Shimada, Yukihisa; Iwata, Yuji; Koizumi, Nozomu
2011-01-01
-type. Transcriptome analysis revealed that genes whose induction was reduced in ire1a/ire1b largely overlapped those in the bzip60 mutant. We observed that the active form of bZIP60 protein detected in the wild-type was missing in ire1a/ire1b. We further demonstrated
Marcel Robischon; Juan Du; Eriko Miura; Andrew Groover
2011-01-01
The secondary growth of a woody stem requires the formation of a vascular cambium at an appropriate position and proper patterning of the vascular tissues derived from the cambium. Class III homeodomain-leucine zipper (HD ZIP) transcription factors have been implicated in polarity determination and patterning in lateral organs and primary vascular tissues and in the...
Function of the HD-Zip I gene Oshox22 in ABA-mediated drought and salt tolerances in rice
Zhang, S.; Kohlen, W.; Jiang, L.; Bouwmeester, H.J.; Meijer, A.H.; Schluepmann, H.; Liu, C.M.; Ouwerkerk, P.B.F.
2012-01-01
Oshox22 belongs to the homeodomain-leucine zipper (HD-Zip) family I of transcription factors, most of which have unknown functions. Here we show that the expression of Oshox22 is strongly induced by salt stress, abscisic acid (ABA), and polyethylene glycol treatment (PEG), and weakly by cold stress.
Quasiparticle propagation in aluminum fins and tungsten TES dynamics in the CDMS ZIP detector
Energy Technology Data Exchange (ETDEWEB)
Pyle, M. [Department of Physics, Stanford University, Stanford, CA 94305 (United States)]. E-mail: mpyle1@stanford.edu; Brink, P.L. [Department of Physics, Stanford University, Stanford, CA 94305 (United States); Cabrera, B. [Department of Physics, Stanford University, Stanford, CA 94305 (United States); Castle, J.P. [Department of Physics, Stanford University, Stanford, CA 94305 (United States); Colling, P. [Department of Physics, Stanford University, Stanford, CA 94305 (United States); Chang, C.L. [Department of Physics, Stanford University, Stanford, CA 94305 (United States); Cooley, J. [Department of Physics, Stanford University, Stanford, CA 94305 (United States); Lipus, T. [Department of Physics, Stanford University, Stanford, CA 94305 (United States); Ogburn, R.W. [Department of Physics, Stanford University, Stanford, CA 94305 (United States); Young, B.A. [Department of Physics, Santa Clara University, Santa Clara, CA 95053 (United States)
2006-04-15
With the aim of improving the rejection of surface beta contamination on the CDMS ZIP detector, we have studied the effectiveness of our phonon pulse-shape discrimination by matching a Monte Carlo calculation to data from a 350{mu}m long Al fin with W TESs (Transition-Edge Sensors) at both ends. From this fit, we determined the Al film diffusivity to be D{sub Al}=0.010+/-0.001m{sup 2}/s, the quasiparticle trapping length in the Al fin to be l{sub trap}=180+/-10{mu}m, and the Al to W TES transmission to be f{sub Al/W}=0.002+/-0.001.
Zipping, entanglement, and the elastic modulus of aligned single-walled carbon nanotube films
Won, Yoonjin; Gao, Yuan; Panzer, Matthew A.; Xiang, Rong; Maruyama, Shigeo; Kenny, Thomas W.; Cai, Wei; Goodson, Kenneth E.
2013-01-01
Reliably routing heat to and from conversion materials is a daunting challenge for a variety of innovative energy technologies––from thermal solar to automotive waste heat recovery systems––whose efficiencies degrade due to massive thermomechanical stresses at interfaces. This problem may soon be addressed by adhesives based on vertically aligned carbon nanotubes, which promise the revolutionary combination of high through-plane thermal conductivity and vanishing in-plane mechanical stiffness. Here, we report the data for the in-plane modulus of aligned single-walled carbon nanotube films using a microfabricated resonator method. Molecular simulations and electron microscopy identify the nanoscale mechanisms responsible for this property. The zipping and unzipping of adjacent nanotubes and the degree of alignment and entanglement are shown to govern the spatially varying local modulus, thereby providing the route to engineered materials with outstanding combinations of mechanical and thermal properties. PMID:24309375
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, and anadromous fish species in Central California. Vector polygons in this data set...
Sensitivity of Coastal Environments and Wildlife to Spilled Oil: Hudson River: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, anadromous, and freshwater fish species in the Hudson River. Vector polygons in this...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for amphibians and reptiles in Central California. Vector polygons in this data set represent sea turtle...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains management area data for National Wildlife Refuges in the Aleutian Islands, Alaska. Vector polygons in this data set represent management...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for sea turtles, estuarine turtles, and gopher tortoise in Mississippi. Vector polygons in this data set...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
Abandoned Uranium Mine (AUM) Region Polygons, Navajo Nation, 2016, US EPA Region 9
U.S. Environmental Protection Agency — This GIS dataset contains polygon features representing the boundaries of the six Abandoned Uranium Mines (AUM) Regions, including the: Central, Eastern, Northern,...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, freshwater, and anadromous fish species in Northwest Arctic, Alaska. Vector polygons...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing coastal wetlands classified according to the Environmental Sensitivity Index (ESI) classification system for...
Cook Inlet and Kenai Peninsula, Alaska ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains biological resource data for marine mammals in Cook Inlet and Kenai Peninsula, Alaska. Vector polygons in this data set represent locations of...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine and estuarine invertebrate species for the Hudson River. Vector polygons in this data set...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for dolphin and manatees in Mississippi. Vector polygons in this data set represent marine mammal...
U.S. Environmental Protection Agency — This is a polygon feature dataset with areas along the shoreline of the Hawaiian islands. The National Coastal Condition Assessment (NCCA) is a national coastal...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for endangered plants for the Upper Coast of Texas. Vector polygons in this data set represent occurrence...
Sensitivity of Coastal Environments and Wildlife to Spilled Oil: South Florida: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine and estuarine fish species in South Florida. Vector polygons in this data set represent fish...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for South...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains benthic habitats, including coral reef and hardbottom, seagrass, algae, and others in [for] South Florida. Vector polygons in the data set...
National Oceanic and Atmospheric Administration, Department of Commerce — The ESIP data set contains vector polygons representing the shoreline and coastal habitats of South Florida classified according to the Environmental Sensitivity...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for sea turtles and estuarine frogs and turtles in Northern California. Vector polygons in this data set...
National Priorities List (NPL) Site Polygons, Region 9, 2012, US EPA Region 9
U.S. Environmental Protection Agency — NPL site POLYGON locations for the US EPA Region 9. NPL (National Priorities List) sites are hazardous waste sites that are eligible for extensive long-term cleanup...
National Priorities List (NPL) Site Polygons, Region 9, 2010, US EPA Region 9
U.S. Environmental Protection Agency — NPL site POLYGON locations for the US EPA Region 9. NPL (National Priorities List) sites are hazardous waste sites that are eligible for extensive long-term cleanup...
AMCO Off-Site Air Monitoring Polygons, Oakland CA, 2017, US EPA Region 9
U.S. Environmental Protection Agency — This feature class was developed to support the AMCO Chemical Superfund Site air monitoring process and depicts a single polygon layer, Off-Site Air Monitors,...
National Priorities List (NPL) Site Polygons, Region 9, 2014, US EPA Region 9
U.S. Environmental Protection Agency — NPL site POLYGON locations for the US EPA Region 9. NPL (National Priorities List) sites are hazardous waste sites that are eligible for extensive long-term cleanup...
National Priorities List (NPL) Site Polygons, Region 9, 2013, US EPA Region 9
U.S. Environmental Protection Agency — NPL site POLYGON locations for the US EPA Region 9. NPL (National Priorities List) sites are hazardous waste sites that are eligible for extensive long-term cleanup...
National Priorities List (NPL) Site Polygons, Region 9, 2015, US EPA Region 9
U.S. Environmental Protection Agency — NPL site POLYGON locations for the US EPA Region 9. NPL (National Priorities List) sites are hazardous waste sites that are eligible for extensive long-term cleanup...
Guam and the Northern Mariana Islands ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for dolphins in Guam and the Northern Mariana Islands. Vector polygons in this data set represent marine...
Coastal Resources Atlas: Long Island: T_MAMMAL (Terrestrial Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for northern river otter, mink, muskrat, and beaver for Long Island, New York. Vector polygons in this data...
National Priorities List (NPL) Site Polygons, Region 9, 2017, US EPA Region 9
U.S. Environmental Protection Agency — NPL site POLYGON locations for the US EPA Region 9. NPL (National Priorities List) sites are hazardous waste sites that are eligible for extensive long-term cleanup...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine and estuarine invertebrate species in Northwest Arctic, Alaska. Vector polygons in this data set...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, and brackish water invertebrate species in Mississippi. Vector polygons in this data...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for sea turtles and select estuarine/freshwater reptiles for the Florida Panhandle. Vector polygons in this...
Rhode Island, Connecticut, New York, and New Jersey ESI: INDEX (Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of the U.S. Geological Survey 1:24,000 topographic maps and other map and digital data boundaries...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, and estuarine invertebrate species in New Hampshire. Vector polygons in this data set represent...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine and estuarine invertebrate species for the Upper Coast of Texas. Vector polygons in this data...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, and freshwater fish species for the Upper Coast of Texas. Vector polygons in this...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine and estuarine invertebrate species in South Florida. Vector polygons in this data set represent...
Coastal Resources Atlas: Long Island: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for seals, whales, and porpoises for Long Island, New York. Vector polygons in this data set represent...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine and estuarine invertebrate species in North Carolina. Vector polygons in this data set represent...
Quasi regular polygons and their duals with Coxeter symmetries Dn represented by complex numbers
International Nuclear Information System (INIS)
Koca, M; Koca, N O
2011-01-01
This paper deals with tiling of the plane by quasi regular polygons and their duals. The problem is motivated from the fact that the graphene, infinite number of carbon molecules forming a honeycomb lattice, may have states with two bond lengths and equal bond angles or one bond length and different bond angles. We prove that the Euclidean plane can be tiled with two tiles consisting of quasi regular hexagons with two different lengths (isogonal hexagons) and regular hexagons. The dual lattice is constructed with the isotoxal hexagons (equal edges but two different interior angles) and regular hexagons. We also give similar tilings of the plane with the quasi regular polygons along with the regular polygons possessing the Coxeter symmetries D n , n=2,3,4,5. The group elements as well as the vertices of the polygons are represented by the complex numbers.
The packing of two species of polygons on the square lattice
International Nuclear Information System (INIS)
Dei Cont, David; Nienhuis, Bernard
2004-01-01
We decorate the square lattice with two species of polygons under the constraint that every lattice edge is covered by only one polygon and every vertex is visited by both types of polygons. We end up with a 24-vertex model which is known in the literature as the fully packed double loop model (FPL 2 ). In the particular case in which the fugacities of the polygons are the same, the model admits an exact solution. The solution is obtained using coordinate Bethe ansatz and provides a closed expression for the free energy. In particular, we find the free energy of the four-colouring model and the double Hamiltonian walk and recover the known entropy of the Ice model. When both fugacities are set equal to 2 the model undergoes an infinite-order phase transition
Measuring Historical Coastal Change using GIS and the Change Polygon Approach
Smith, M.J.; Cromley, R.G.
2012-01-01
This study compares two automated approaches, the transect-from-baseline technique and a new change polygon method, for quantifying historical coastal change over time. The study shows that the transect-from-baseline technique is complicated by choice of a proper baseline as well as generating transects that intersect with each other rather than with the nearest shoreline. The change polygon method captures the full spatial difference between the positions of the two shorelines and average coastal change is the defined as the ratio of the net area divided by the shoreline length. Although then change polygon method is sensitive to the definition and measurement of shoreline length, the results are more invariant to parameter changes than the transect-from-baseline method, suggesting that the change polygon technique may be a more robust coastal change method. ?? 2012 Blackwell Publishing Ltd.
Supramolecule-to-supramolecule transformations of coordination-driven self-assembled polygons.
Zhao, Liang; Northrop, Brian H; Stang, Peter J
2008-09-10
Two types of supramolecular transformations, wherein a self-assembled Pt(II)-pyridyl metal-organic polygon is controllably converted into an alternative polygon, have been achieved through the reaction between cobalt carbonyl and the acetylene moiety of a dipyridyl donor ligand. A [6 + 6] hexagon is transformed into two [3 + 3] hexagons, and a triangle-square mixture is converted into [2 + 2] rhomboids. 1H and 31P NMR spectra are used to track the transformation process and evaluate the yield of new self-assembled polygons. Such transformed species are identified by electrospray ionization (ESI) mass spectrometry. This new kind of supramolecule-to-supramolecule transformations provides a viable means for constructing, and then converting, new self-assembled polygons.
Convex lattice polygons of fixed area with perimeter-dependent weights.
Rajesh, R; Dhar, Deepak
2005-01-01
We study fully convex polygons with a given area, and variable perimeter length on square and hexagonal lattices. We attach a weight tm to a convex polygon of perimeter m and show that the sum of weights of all polygons with a fixed area s varies as s(-theta(conv))eK(t)square root(s) for large s and t less than a critical threshold tc, where K(t) is a t-dependent constant, and theta(conv) is a critical exponent which does not change with t. Using heuristic arguments, we find that theta(conv) is 1/4 for the square lattice, but -1/4 for the hexagonal lattice. The reason for this unexpected nonuniversality of theta(conv) is traced to existence of sharp corners in the asymptotic shape of these polygons.
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
Virginia ESI: ESI (Environmental Sensitivity Index Shoreline Types - Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing the shoreline and coastal habitats for Virginia, classified according to the Environmental Sensitivity...
Maryland ESI: ESI (Environmental Sensitivity Index Shoreline Types - Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing the shoreline and coastal habitats for Maryland, classified according to the Environmental Sensitivity...
Rhode Island, Connecticut, New York, and New Jersey ESI: T_MAMMAL (Terrestrial Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for small mammal species in coastal Rhode Island, Connecticut, New York, and New Jersey. Vector polygons in...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, anadromous, and brackish/freshwater fish species in North Carolina. Vector polygons...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Southern...
Guam and the Northern Mariana Islands ESI: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Guam and the...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Central...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing management area data for Designated Critical Habitats, National Park Service properties, Wildlife Refuges, and...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Northern...
Rhode Island, Connecticut, New York, and New Jersey ESI: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Rhode Island,...
Cook Inlet and Kenai Peninsula, Alaska ESI: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Cook Inlet...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for New...
U.S. Environmental Protection Agency — This feature class contains the 64 tax map key polygons across the state of Hawaii that have been inspected by US EPA Pacific Southwest Enforcement Division as of...
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing the shoreline and coastal habitats of Cook Inlet and Kenai Peninsula, Alaska, classified according to...
Model of Random Polygon Particles for Concrete and Mesh Automatic Subdivision
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
In order to study the constitutive behavior of concrete in mesoscopic level, a new method is proposed in this paper. This method uses random polygon particles to simulate full grading broken aggregates of concrete. Based on computational geometry, we carry out the automatic generation of the triangle finite element mesh for the model of random polygon particles of concrete. The finite element mesh generated in this paper is also applicable to many other numerical methods.
In-gap corner states in core-shell polygonal quantum rings.
Sitek, Anna; Ţolea, Mugurel; Niţă, Marian; Serra, Llorenç; Gudmundsson, Vidar; Manolescu, Andrei
2017-01-10
We study Coulomb interacting electrons confined in polygonal quantum rings. We focus on the interplay of localization at the polygon corners and Coulomb repulsion. Remarkably, the Coulomb repulsion allows the formation of in-gap states, i.e., corner-localized states of electron pairs or clusters shifted to energies that were forbidden for non-interacting electrons, but below the energies of corner-side-localized states. We specify conditions allowing optical excitation to those states.
In-gap corner states in core-shell polygonal quantum rings
Sitek, Anna; Ţolea, Mugurel; Niţă, Marian; Serra, Llorenç; Gudmundsson, Vidar; Manolescu, Andrei
2017-01-01
We study Coulomb interacting electrons confined in polygonal quantum rings. We focus on the interplay of localization at the polygon corners and Coulomb repulsion. Remarkably, the Coulomb repulsion allows the formation of in-gap states, i.e., corner-localized states of electron pairs or clusters shifted to energies that were forbidden for non-interacting electrons, but below the energies of corner-side-localized states. We specify conditions allowing optical excitation to those states.
On the mean and variance of the writhe of random polygons
International Nuclear Information System (INIS)
Portillo, J; Scharein, R; Arsuaga, J; Vazquez, M; Diao, Y
2011-01-01
We here address two problems concerning the writhe of random polygons. First, we study the behavior of the mean writhe as a function length. Second, we study the variance of the writhe. Suppose that we are dealing with a set of random polygons with the same length and knot type, which could be the model of some circular DNA with the same topological property. In general, a simple way of detecting chirality of this knot type is to compute the mean writhe of the polygons; if the mean writhe is non-zero then the knot is chiral. How accurate is this method? For example, if for a specific knot type K the mean writhe decreased to zero as the length of the polygons increased, then this method would be limited in the case of long polygons. Furthermore, we conjecture that the sign of the mean writhe is a topological invariant of chiral knots. This sign appears to be the same as that of an 'ideal' conformation of the knot. We provide numerical evidence to support these claims, and we propose a new nomenclature of knots based on the sign of their expected writhes. This nomenclature can be of particular interest to applied scientists. The second part of our study focuses on the variance of the writhe, a problem that has not received much attention in the past. In this case, we focused on the equilateral random polygons. We give numerical as well as analytical evidence to show that the variance of the writhe of equilateral random polygons (of length n) behaves as a linear function of the length of the equilateral random polygon.
On the mean and variance of the writhe of random polygons.
Portillo, J; Diao, Y; Scharein, R; Arsuaga, J; Vazquez, M
We here address two problems concerning the writhe of random polygons. First, we study the behavior of the mean writhe as a function length. Second, we study the variance of the writhe. Suppose that we are dealing with a set of random polygons with the same length and knot type, which could be the model of some circular DNA with the same topological property. In general, a simple way of detecting chirality of this knot type is to compute the mean writhe of the polygons; if the mean writhe is non-zero then the knot is chiral. How accurate is this method? For example, if for a specific knot type K the mean writhe decreased to zero as the length of the polygons increased, then this method would be limited in the case of long polygons. Furthermore, we conjecture that the sign of the mean writhe is a topological invariant of chiral knots. This sign appears to be the same as that of an "ideal" conformation of the knot. We provide numerical evidence to support these claims, and we propose a new nomenclature of knots based on the sign of their expected writhes. This nomenclature can be of particular interest to applied scientists. The second part of our study focuses on the variance of the writhe, a problem that has not received much attention in the past. In this case, we focused on the equilateral random polygons. We give numerical as well as analytical evidence to show that the variance of the writhe of equilateral random polygons (of length n ) behaves as a linear function of the length of the equilateral random polygon.
International Nuclear Information System (INIS)
Mori, N.; Kobayashi, K.
1996-01-01
A two-dimensional neutron diffusion equation is solved for regular polygonal regions by the finite Fourier transformation, and geometrical bucklings are calculated for regular 3-10 polygonal regions. In the case of the regular triangular region, it is found that a simple and rigorous analytic solution is obtained for the geometrical buckling and the distribution of the neutron current along the outer boundary. (author)
Identifying Conventionally Sub-Seismic Faults in Polygonal Fault Systems
Fry, C.; Dix, J.
2017-12-01
Polygonal Fault Systems (PFS) are prevalent in hydrocarbon basins globally and represent potential fluid pathways. However the characterization of these pathways is subject to the limitations of conventional 3D seismic imaging; only capable of resolving features on a decametre scale horizontally and metres scale vertically. While outcrop and core examples can identify smaller features, they are limited by the extent of the exposures. The disparity between these scales can allow for smaller faults to be lost in a resolution gap which could mean potential pathways are left unseen. Here the focus is upon PFS from within the London Clay, a common bedrock that is tunnelled into and bears construction foundations for much of London. It is a continuation of the Ieper Clay where PFS were first identified and is found to approach the seafloor within the Outer Thames Estuary. This allows for the direct analysis of PFS surface expressions, via the use of high resolution 1m bathymetric imaging in combination with high resolution seismic imaging. Through use of these datasets surface expressions of over 1500 faults within the London Clay have been identified, with the smallest fault measuring 12m and the largest at 612m in length. The displacements over these faults established from both bathymetric and seismic imaging ranges from 30cm to a couple of metres, scales that would typically be sub-seismic for conventional basin seismic imaging. The orientations and dimensions of the faults within this network have been directly compared to 3D seismic data of the Ieper Clay from the offshore Dutch sector where it exists approximately 1km below the seafloor. These have typical PFS attributes with lengths of hundreds of metres to kilometres and throws of tens of metres, a magnitude larger than those identified in the Outer Thames Estuary. The similar orientations and polygonal patterns within both locations indicates that the smaller faults exist within typical PFS structure but are
Co-evolution of polygonal and scalloped terrains, southwestern Utopia Planitia, Mars
Haltigin, T. W.; Pollard, W. H.; Dutilleul, P.; Osinski, G. R.; Koponen, L.
2014-02-01
Thermal contraction crack polygons and scalloped depressions, two of the most common landforms found in Utopia Planitia, Mars, have previously been linked to the presence of ice-rich deposits in the subsurface. Although the formation and evolution of these features individually are relatively well understood, little to no effort has been directed towards elucidating possible interactions that occur between them during their development. Thus, the overarching goal of this research was to investigate if there is an evolutionary link between polygonal and scalloped terrains by correlating metrics representing polygon and scallop maturity. A variety of statistical analyses were performed using HiRISE and MOLA datasets to quantify interactions between four sets of polygonal and scalloped terrains. Our results demonstrate the existence of a negative relationship between polygonal subdivision and surface elevation, indicating that polygon networks become more ‘evolved’ as the surface subsides. These results suggest that the permafrost landscape in Utopia Planitia may once have been extremely ice-rich, and that multiple geomorphic processes may be responsible for its evolution. Ultimately, this work demonstrates that landscape reconstruction is more complete when a system approach is followed, quantifying interactions between landforms as opposed to examining an individual landform in isolation.
The linking number and the writhe of uniform random walks and polygons in confined spaces
International Nuclear Information System (INIS)
Panagiotou, E; Lambropoulou, S; Millett, K C
2010-01-01
Random walks and polygons are used to model polymers. In this paper we consider the extension of the writhe, self-linking number and linking number to open chains. We then study the average writhe, self-linking and linking number of random walks and polygons over the space of configurations as a function of their length. We show that the mean squared linking number, the mean squared writhe and the mean squared self-linking number of oriented uniform random walks or polygons of length n, in a convex confined space, are of the form O(n 2 ). Moreover, for a fixed simple closed curve in a convex confined space, we prove that the mean absolute value of the linking number between this curve and a uniform random walk or polygon of n edges is of the form O(√n). Our numerical studies confirm those results. They also indicate that the mean absolute linking number between any two oriented uniform random walks or polygons, of n edges each, is of the form O(n). Equilateral random walks and polygons are used to model polymers in θ-conditions. We use numerical simulations to investigate how the self-linking and linking number of equilateral random walks scale with their length.
Directory of Open Access Journals (Sweden)
Xiao-Long Wang
2015-01-01
Full Text Available The basic leucine zipper (bZIP transcription factors are the most diverse members of dimerizing transcription factors. In the present study, 50, 116, and 47 bZIP genes were identified in Malus domestica (apple, Prunus persica (peach, and Fragaria vesca (strawberry, respectively. Species-specific duplication was the main contributor to the large number of bZIPs observed in apple. After WGD in apple genome, orthologous bZIP genes corresponding to strawberry on duplicated regions in apple genome were retained. However, in peach ancestor, these syntenic regions were quickly lost or deleted. Maybe the positive selection contributed to the expansion of clade S to adapt to the development and environment stresses. In addition, purifying selection was mainly responsible for bZIP sequence-specific DNA binding. The analysis of orthologous pairs between chromosomes indicates that these orthologs derived from one gene duplication located on one of the nine ancient chromosomes in the Rosaceae. The comparative analysis of bZIP genes in three species provides information on the evolutionary fate of bZIP genes in apple and peach after they diverged from strawberry.
Two-loop polygon Wilson loops in N = 4 SYM
International Nuclear Information System (INIS)
Anastasiou, C.; Brandhuber, A.; Heslop, P.; Spence, B.; Travaglini, G.; Khoze, V.V.
2009-01-01
We compute for the first time the two-loop corrections to arbitrary n-gon lightlike Wilson loops in N = 4 supersymmetric Yang-Mills theory, using efficient numerical methods. The calculation is motivated by the remarkable agreement between the finite part of planar six-point MHV amplitudes and hexagon Wilson loops which has been observed at two loops. At n = 6 we confirm that the ABDK/BDS ansatz must be corrected by adding a remainder function, which depends only on conformally invariant ratios of kinematic variables. We numerically compute remainder functions for n = 7,8 and verify dual conformal invariance. Furthermore, we study simple and multiple collinear limits of the Wilson loop remainder functions and demonstrate that they have precisely the form required by the collinear factorisation of the corresponding two-loop n-point amplitudes. The number of distinct diagram topologies contributing to the n-gon Wilson loops does not increase with n, and there is a fixed number of 'master integrals', which we have computed. Thus we have essentially computed general polygon Wilson loops, and if the correspondence with amplitudes continues to hold, all planar n-point two-loop MHV amplitudes in the N = 4 theory.
Conical twist fields and null polygonal Wilson loops
Castro-Alvaredo, Olalla A.; Doyon, Benjamin; Fioravanti, Davide
2018-06-01
Using an extension of the concept of twist field in QFT to space-time (external) symmetries, we study conical twist fields in two-dimensional integrable QFT. These create conical singularities of arbitrary excess angle. We show that, upon appropriate identification between the excess angle and the number of sheets, they have the same conformal dimension as branch-point twist fields commonly used to represent partition functions on Riemann surfaces, and that both fields have closely related form factors. However, we show that conical twist fields are truly different from branch-point twist fields. They generate different operator product expansions (short distance expansions) and form factor expansions (large distance expansions). In fact, we verify in free field theories, by re-summing form factors, that the conical twist fields operator product expansions are correctly reproduced. We propose that conical twist fields are the correct fields in order to understand null polygonal Wilson loops/gluon scattering amplitudes of planar maximally supersymmetric Yang-Mills theory.
A study on the nuclear computer code maintenance and management system
International Nuclear Information System (INIS)
Kim, Yeon Seung; Huh, Young Hwan; Lee, Jong Bok; Choi, Young Gil; Suh, Soong Hyok; Kang, Byong Heon; Kim, Hee Kyung; Kim, Ko Ryeo; Park, Soo Jin
1990-12-01
According to current software development and quality assurance trends. It is necessary to develop computer code management system for nuclear programs. For this reason, the project started in 1987. Main objectives of the project are to establish a nuclear computer code management system, to secure software reliability, and to develop nuclear computer code packages. Contents of performing the project in this year were to operate and maintain computer code information system of KAERI computer codes, to develop application tool, AUTO-i, for solving the 1st and 2nd moments of inertia on polygon or circle, and to research nuclear computer code conversion between different machines. For better supporting the nuclear code availability and reliability, assistance from users who are using codes is required. Lastly, for easy reference about the codes information, we presented list of code names and information on the codes which were introduced or developed during this year. (Author)
International Nuclear Information System (INIS)
Fox, Christopher; Romeijn, H. Edwin; Dempsey, James F.
2006-01-01
We present work on combining three algorithms to improve ray-tracing efficiency in radiation therapy dose computation. The three algorithms include: An improved point-in-polygon algorithm, incremental voxel ray tracing algorithm, and stereographic projection of beamlets for voxel truncation. The point-in-polygon and incremental voxel ray-tracing algorithms have been used in computer graphics and nuclear medicine applications while the stereographic projection algorithm was developed by our group. These algorithms demonstrate significant improvements over the current standard algorithms in peer reviewed literature, i.e., the polygon and voxel ray-tracing algorithms of Siddon for voxel classification (point-in-polygon testing) and dose computation, respectively, and radius testing for voxel truncation. The presented polygon ray-tracing technique was tested on 10 intensity modulated radiation therapy (IMRT) treatment planning cases that required the classification of between 0.58 and 2.0 million voxels on a 2.5 mm isotropic dose grid into 1-4 targets and 5-14 structures represented as extruded polygons (a.k.a. Siddon prisms). Incremental voxel ray tracing and voxel truncation employing virtual stereographic projection was tested on the same IMRT treatment planning cases where voxel dose was required for 230-2400 beamlets using a finite-size pencil-beam algorithm. Between a 100 and 360 fold cpu time improvement over Siddon's method was observed for the polygon ray-tracing algorithm to perform classification of voxels for target and structure membership. Between a 2.6 and 3.1 fold reduction in cpu time over current algorithms was found for the implementation of incremental ray tracing. Additionally, voxel truncation via stereographic projection was observed to be 11-25 times faster than the radial-testing beamlet extent approach and was further improved 1.7-2.0 fold through point-classification using the method of translation over the cross product technique
Friedman, Alinda; Montello, Daniel R; Burte, Heather
2012-09-01
We conducted 3 experiments to examine the category adjustment model (Huttenlocher, Hedges, & Duncan, 1991) in circumstances in which the category boundaries were irregular schematized polygons made from outlines of maps. For the first time, accuracy was tested when only perceptual and/or existing long-term memory information about identical locations was cued. Participants from Alberta, Canada and California received 1 of 3 conditions: dots-only, in which a dot appeared within the polygon, and after a 4-s dynamic mask the empty polygon appeared and the participant indicated where the dot had been; dots-and-names, in which participants were told that the first polygon represented Alberta/California and that each dot was in the correct location for the city whose name appeared outside the polygon; and names-only, in which there was no first polygon, and participants clicked on the city locations from extant memory alone. Location recall in the dots-only and dots-and-names conditions did not differ from each other and had small but significant directional errors that pointed away from the centroids of the polygons. In contrast, the names-only condition had large and significant directional errors that pointed toward the centroids. Experiments 2 and 3 eliminated the distribution of stimuli and overall screen position as causal factors. The data suggest that in the "classic" category adjustment paradigm, it is difficult to determine a priori when Bayesian cue combination is applicable, making Bayesian analysis less useful as a theoretical approach to location estimation. PsycINFO Database Record (c) 2012 APA, all rights reserved.
High-order polygonal discontinuous Petrov-Galerkin (PolyDPG) methods using ultraweak formulations
Vaziri Astaneh, Ali; Fuentes, Federico; Mora, Jaime; Demkowicz, Leszek
2018-04-01
This work represents the first endeavor in using ultraweak formulations to implement high-order polygonal finite element methods via the discontinuous Petrov-Galerkin (DPG) methodology. Ultraweak variational formulations are nonstandard in that all the weight of the derivatives lies in the test space, while most of the trial space can be chosen as copies of $L^2$-discretizations that have no need to be continuous across adjacent elements. Additionally, the test spaces are broken along the mesh interfaces. This allows one to construct conforming polygonal finite element methods, termed here as PolyDPG methods, by defining most spaces by restriction of a bounding triangle or box to the polygonal element. The only variables that require nontrivial compatibility across elements are the so-called interface or skeleton variables, which can be defined directly on the element boundaries. Unlike other high-order polygonal methods, PolyDPG methods do not require ad hoc stabilization terms thanks to the crafted stability of the DPG methodology. A proof of convergence of the form $h^p$ is provided and corroborated through several illustrative numerical examples. These include polygonal meshes with $n$-sided convex elements and with highly distorted concave elements, as well as the modeling of discontinuous material properties along an arbitrary interface that cuts a uniform grid. Since PolyDPG methods have a natural a posteriori error estimator a polygonal adaptive strategy is developed and compared to standard adaptivity schemes based on constrained hanging nodes. This work is also accompanied by an open-source $\\texttt{PolyDPG}$ software supporting polygonal and conventional elements.
Louisiana Geographic Information Center — This data set contains polygons representing the Environmental Sensitivity Index (ESI) classification of coastal Louisiana. The ESI is a classification and ranking...
Heil, Martin; Jansen-Osmann, Petra
2008-05-01
Sex differences in mental rotation were investigated as a function of stimulus complexity with a sample size of N = 72. Replicating earlier findings with polygons, mental rotation was faster for males than for females, and reaction time increased with more complex polygons. Additionally, sex differences increased for complex polygons. Most importantly, however, mental rotation speed decreased with increasing complexity for women but did not change for men. Thus, the sex effects reflect a difference in strategy, with women mentally rotating the polygons in an analytic, piecemeal fashion and men using a holistic mode of mental rotation.
Directory of Open Access Journals (Sweden)
Fabio Burderi
2007-05-01
Full Text Available Motivated by the study of decipherability conditions for codes weaker than Unique Decipherability (UD, we introduce the notion of coding partition. Such a notion generalizes that of UD code and, for codes that are not UD, allows to recover the ``unique decipherability" at the level of the classes of the partition. By tacking into account the natural order between the partitions, we define the characteristic partition of a code X as the finest coding partition of X. This leads to introduce the canonical decomposition of a code in at most one unambiguouscomponent and other (if any totally ambiguouscomponents. In the case the code is finite, we give an algorithm for computing its canonical partition. This, in particular, allows to decide whether a given partition of a finite code X is a coding partition. This last problem is then approached in the case the code is a rational set. We prove its decidability under the hypothesis that the partition contains a finite number of classes and each class is a rational set. Moreover we conjecture that the canonical partition satisfies such a hypothesis. Finally we consider also some relationships between coding partitions and varieties of codes.
Biophysical properties of regions flanking the bHLH-Zip motif in the p22 Max protein
International Nuclear Information System (INIS)
Pursglove, Sharon E.; Fladvad, Malin; Bellanda, Massimo; Moshref, Ahmad; Henriksson, Marie; Carey, Jannette; Sunnerhagen, Maria
2004-01-01
The Max protein is the central dimerization partner in the Myc-Max-Mad network of transcriptional regulators, and a founding structural member of the family of basic-helix-loop-helix (bHLH)-leucine zipper (Zip) proteins. Biologically important regions flanking its bHLH-Zip motif have been disordered or absent in crystal structures. The present study shows that these regions are resistant to proteolysis in both the presence and absence of DNA, and that Max dimers containing both flanking regions have significantly higher helix content as measured by circular dichroism than that predicted from the crystal structures. Nuclear magnetic resonance measurements in the absence of DNA also support the inferred structural order. Deletion of both flanking regions is required to achieve maximal DNA affinity as measured by EMSA. Thus, the previously observed functionalities of these Max regions in DNA binding, phosphorylation, and apoptosis are suggested to be linked to structural properties
HTLV-1 bZIP factor induces T-cell lymphoma and systemic inflammation in vivo.
Directory of Open Access Journals (Sweden)
Yorifumi Satou
2011-02-01
Full Text Available Human T-cell leukemia virus type 1 (HTLV-1 is the causal agent of a neoplastic disease of CD4+ T cells, adult T-cell leukemia (ATL, and inflammatory diseases including HTLV-1 associated myelopathy/tropical spastic paraparesis, dermatitis, and inflammatory lung diseases. ATL cells, which constitutively express CD25, resemble CD25+CD4+ regulatory T cells (T(reg. Approximately 60% of ATL cases indeed harbor leukemic cells that express FoxP3, a key transcription factor for T(reg cells. HTLV-1 encodes an antisense transcript, HTLV-1 bZIP factor (HBZ, which is expressed in all ATL cases. In this study, we show that transgenic expression of HBZ in CD4+ T cells induced T-cell lymphomas and systemic inflammation in mice, resembling diseases observed in HTLV-1 infected individuals. In HBZ-transgenic mice, CD4+Foxp3+ T(reg cells and effector/memory CD4+ T cells increased in vivo. As a mechanism of increased T(reg cells, HBZ expression directly induced Foxp3 gene transcription in T cells. The increased CD4+Foxp3+ T(reg cells in HBZ transgenic mice were functionally impaired while their proliferation was enhanced. HBZ could physically interact with Foxp3 and NFAT, thereby impairing the suppressive function of T(reg cells. Thus, the expression of HBZ in CD4+ T cells is a key mechanism of HTLV-1-induced neoplastic and inflammatory diseases.
Flavonoids modify root growth and modulate expression of SHORT-ROOT and HD-ZIP III.
Franco, Danilo Miralha; Silva, Eder Marques; Saldanha, Luiz Leonardo; Adachi, Sérgio Akira; Schley, Thayssa Rabelo; Rodrigues, Tatiane Maria; Dokkedal, Anne Ligia; Nogueira, Fabio Tebaldi Silveira; Rolim de Almeida, Luiz Fernando
2015-09-01
Flavonoids are a class of distinct compounds produced by plant secondary metabolism that inhibit or promote plant development and have a relationship with auxin transport. We showed that, in terms of root development, Copaifera langsdorffii leaf extracts has an inhibitory effect on most flavonoid components compared with the application of exogenous flavonoids (glycosides and aglycones). These compounds alter the pattern of expression of the SHORT-ROOT and HD-ZIP III transcription factor gene family and cause morpho-physiological alterations in sorghum roots. In addition, to examine the flavonoid auxin interaction in stress, we correlated the responses with the effects of exogenous application of auxin and an auxin transport inhibitor. The results show that exogenous flavonoids inhibit primary root growth and increase the development of lateral roots. Exogenous flavonoids also change the pattern of expression of specific genes associated with root tissue differentiation. These findings indicate that flavonoid glycosides can influence the polar transport of auxin, leading to stress responses that depend on auxin. Copyright © 2015 Elsevier GmbH. All rights reserved.