2,238 research outputs found

    Empires and Percolation: Stochastic Merging of Adjacent Regions

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    We introduce a stochastic model in which adjacent planar regions A,BA, B merge stochastically at some rate λ(A,B)\lambda(A,B), and observe analogies with the well-studied topics of mean-field coagulation and of bond percolation. Do infinite regions appear in finite time? We give a simple condition on λ\lambda for this {\em hegemony} property to hold, and another simple condition for it to not hold, but there is a large gap between these conditions, which includes the case λ(A,B)1\lambda(A,B) \equiv 1. For this case, a non-rigorous analytic argument and simulations suggest hegemony.Comment: 13 page

    Trapping \u3cem\u3ePhyllophaga\u3c/em\u3e spp. (Coleoptera: Scarabaeidae: Melolonthinae) in the United States and Canada Using Sex Attractants

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    The sex pheromone of the scarab beetle, Phyllophaga anxia, is a blend of the methyl esters of two amino acids, L-valine and L-isoleucine. A field trapping study was conducted, deploying different blends of the two compounds at 59 locations in the United States and Canada. More than 57,000 males of 61 Phyllophaga species (Coleoptera: Scarabaeidae: Melolonthinae) were captured and identified. Three major findings included: (1) widespread use of the two compounds [of the 147 Phyllophaga (sensu stricto) species found in the United States and Canada, males of nearly 40% were captured]; (2) in most species intraspecific male response to the pheromone blends was stable between years and over geography; and (3) an unusual pheromone polymorphism was described from P. anxia. Populations at some locations were captured with L-valine methyl ester alone, whereas populations at other locations were captured with L-isoleucine methyl ester alone. At additional locations, the L-valine methyl ester-responding populations and the L-isoleucine methyl ester-responding populations were both present, producing a bimodal capture curve. In southeastern Massachusetts and in Rhode Island, in the United States, P. anxia males were captured with blends of L-valine methyl ester and L-isoleucine methyl ester

    Efektivitas Bappeda dalam Perencanaan Pembangunan Kota Padang di Era Otonomi Daerah

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    BAPPEDA is one of institution in a region that has an important role in the Regional development planning coordination. Function of this institution is very important that one could say that the successful of the development planning coordination implementation or not in a region, especially in the autonomy era, is more relied on the effectiveness of the Bappeda in performing its functions. Therefore, development of performance quality of the Bappeda needs to be improved or increased by coordination with related agentscies Started from the phenomenon given above, this was study aimed to: (1) know the effectiveness of the Bappeda of the Padang Municipality in performing its functions to enforce the development planning coordinations in the region; 2) know factors inhibiting the effectiveness of the BAPPEDA function of the Padang Municipality in enforcing development and planning coordination in making program/project. This research utilized qualitative approach by taking location at the Bappeda office, Padang Municipality. Collecting is conducted by using interview, observation and documentation methods. Data analysis in this research used interactive pattern analysis as developed by Miles and Hubberman (1992) including data reduction, data presentation, and drawing conclusion or verification. Result of the study showed that: (1) to optimize the Bappeda function in the autonomy era can be done by increasing the effectiveness of the Bappeda function in enforcement the development planning coordination in the region, improving APBD composition and implementation of monitoring function and evaluation of all activities; 2) factors inhibiting the effectiveness of theBappeda function in enforcing the development coordination in the region are low of professionalism of staffs, less of tool and equipment, weak of structure and working procedure and information system

    Molecular regulation of GLUT-4 targeting in 3T3-L1 adipocytes

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    Insulin stimulates glucose transport in muscle and adipose tissue by triggering the movement of the glucose transporter GLUT-4 from an intracellular compartment to the cell surface. Fundamental to this process is the intracellular sequestration of GLUT-4 in nonstimulated cells. Two distinct targeting motifs in the amino and carboxy termini of GLUT-4 have been previously identified by expressing chimeras comprised of portions of GLUT-4 and GLUT-1, a transporter isoform that is constitutively targeted to the cell surface, in heterologous cells. These motifs-FQQ1 in the NH terminus and LL in the COOH terminus-resemble endocytic signals that have been described in other proteins. In the present study we have investigated the roles of these motifs in GLUT-4 targeting in insulin-sensitive cells. Epitope-tagged GLUT-4 constructs engineered to differentiate between endogenous and transfected GLUT-4 were stably expressed in 3T3-L1 adipocytes. Targeting was assessed in cells incubated in the presence or absence of insulin by subcellular fractionation. The targeting of epitope-tagged GLUT-4 was indistinguishable from endogenous GLUT-4. Mutation of the FQQI motif (F to A) caused GLUT-4 to constitutively accumulate at the cell surface regardless of expression level. Mutation of the dileucine motif (LL to AA) caused an increase in cell surface distribution only at higher levels of expression, but the overall cell surface distribution of this mutant was less than that of the amino-terminal mutants. Both NH- and COOH-terminal mutants retained insulin-dependent movement from an intracellular to a cell surface locale, suggesting that neither of these motifs is involved in the insulin-dependent redistribution of GLUT-4. We conclude that the phenylalanine-based NH-terminal and the dileucine-based COOH-terminal motifs play important and distinct roles in GLUT-4 targeting in 3T3-L1 adipocytes

    The Horse and Deer Flies (Diptera: Tabanidae) of Rhode Island

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    The Tabanidae of Rhode Island were surveyed using Rhode Island canopy traps placed at 20 locations in the state during the summers of 1999 and 2000. In total, 5,120 flies were collected, which included 55 species in the genera Chrysops, Hybomitra, Tabanus, Merycomyia, and Stonemyia. Distributional and ecological information is provided for each species in Rhode Island

    Corrections to Tribimaximal Mixing from Nondegenerate Phases

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    We propose a seesaw scenario that possible corrections to the tribimaximal pattern of lepton mixing are due to the small phase splitting of the right-handed neutrino mass matrix. we show that the small deviations can be expressed analytically in terms of two splitting parameters(δ1\delta_1 and δ2\delta_2) in the leading order. The solar mixing angle θ12\theta_{12} favors a relatively smaller value compared to zero order value (35.335.3^\circ), and the Dirac type CP phase δ\delta chooses a nearly maximal one. The two Majorana type CP phases ρ\rho and σ\sigma turn out to be a nearly linear dependence. Also a normal hierarchy neutrino mass spectrum is favored due to the stability of perturbation calculations.Comment: 19 pages 6 figures, Accepted by Mod. Phy. Lett.

    Finding and counting vertex-colored subtrees

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    The problems studied in this article originate from the Graph Motif problem introduced by Lacroix et al. in the context of biological networks. The problem is to decide if a vertex-colored graph has a connected subgraph whose colors equal a given multiset of colors MM. It is a graph pattern-matching problem variant, where the structure of the occurrence of the pattern is not of interest but the only requirement is the connectedness. Using an algebraic framework recently introduced by Koutis et al., we obtain new FPT algorithms for Graph Motif and variants, with improved running times. We also obtain results on the counting versions of this problem, proving that the counting problem is FPT if M is a set, but becomes W[1]-hard if M is a multiset with two colors. Finally, we present an experimental evaluation of this approach on real datasets, showing that its performance compares favorably with existing software.Comment: Conference version in International Symposium on Mathematical Foundations of Computer Science (MFCS), Brno : Czech Republic (2010) Journal Version in Algorithmic

    The Nucleon Spectral Function at Finite Temperature and the Onset of Superfluidity in Nuclear Matter

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    Nucleon selfenergies and spectral functions are calculated at the saturation density of symmetric nuclear matter at finite temperatures. In particular, the behaviour of these quantities at temperatures above and close to the critical temperature for the superfluid phase transition in nuclear matter is discussed. It is shown how the singularity in the thermodynamic T-matrix at the critical temperature for superfluidity (Thouless criterion) reflects in the selfenergy and correspondingly in the spectral function. The real part of the on-shell selfenergy (optical potential) shows an anomalous behaviour for momenta near the Fermi momentum and temperatures close to the critical temperature related to the pairing singularity in the imaginary part. For comparison the selfenergy derived from the K-matrix of Brueckner theory is also calculated. It is found, that there is no pairing singularity in the imaginary part of the selfenergy in this case, which is due to the neglect of hole-hole scattering in the K-matrix. From the selfenergy the spectral function and the occupation numbers for finite temperatures are calculated.Comment: LaTex, 23 pages, 21 PostScript figures included (uuencoded), uses prc.sty, aps.sty, revtex.sty, psfig.sty (last included

    Four-particle condensate in strongly coupled fermion systems

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    Four-particle correlations in fermion systems at finite temperatures are investigated with special attention to the formation of a condensate. Instead of the instability of the normal state with respect to the onset of pairing described by the Gorkov equation, a new equation is obtained which describes the onset of quartetting. Within a model calculation for symmetric nuclear matter, we find that below a critical density, the four-particle condensation (alpha-like quartetting) is favored over deuteron condensation (triplet pairing). This pairing-quartetting competition is expected to be a general feature of interacting fermion systems, such as the excition-biexciton system in excited semiconductors. Possible experimental consequences are pointed out.Comment: LaTeX, 11 pages, 2 figures, uses psfig.sty (included), to be published in Phys. Rev. Lett., tentatively scheduled for 13 April 1998 (Volume 80, Number 15

    Grandpaternal-induced transgenerational dietary reprogramming of the unfolded protein response in skeletal muscle

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    Objective: Parental nutrition and lifestyle impact the metabolic phenotype of the offspring. We have reported that grandpaternal chronic high-fat diet (HFD) transgenerationally impairs glucose metabolism in subsequent generations. Here we determined whether grandpaternal diet transgenerationally impacts the transcriptome and lipidome in skeletal muscle. Our aim was to identify tissue-specific pathways involved in transgenerational inheritance of environmental-induced phenotypes. Methods: F0 male Sprague–Dawley rats were fed a HFD or chow for 12 weeks before breeding with chow-fed females to generate the F1 generation. F2 offspring were generated by mating F1 males fed a chow diet with an independent line of chow-fed females. F1 and F2 offspring were fed chow or HFD for 12 weeks. Transcriptomic and LC-MS lipidomic analyses were performed in extensor digitorum longus muscle from F2-females rats. Gene set enrichment analysis (GSEA) was performed to determine pathways reprogrammed by grandpaternal diet. Results: GSEA revealed an enrichment of the unfolded protein response pathway in skeletal muscle of grand-offspring from HFD-fed grandfathers compared to grand-offspring of chow-fed males. Activation of the stress sensor (ATF6α), may be a pivotal point whereby this pathway is activated. Interestingly, skeletal muscle from F1-offspring was not affected in a similar manner. No major changes were observed in the skeletal muscle lipidome profile due to grandpaternal diet. Conclusions: Grandpaternal HFD-induced obesity transgenerationally affected the skeletal muscle transcriptome. This finding further highlights the impact of parental exposure to environmental factors on offspring's development and health
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