2,789 research outputs found

    Modeling of stress-strain state of cement-sand grouting on foundation deformation

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    The application of jet grouting has been becoming more widespread in the reinforcement of building foundations. This technique depends on the characteristic features of the foundation soil, relevant type of foundation and surrounding conditions. The numerical analysis was carried out with three typical load intensities, proving that the intensity of the foundation settlement being influenced by the growth of soil stiffness and strength. The calculation of vertical soil displacements is 7.9 mm before underpinning, while it is 6.5 mm after underpinning. It is defined that the use of jet structures to strengthen the ground base allows to increase the rigidity of the base and to reduce its vertical movement by 20%. The hypothetical displacements were identified of the base by varying of its mechanical properties to the optimal values

    Economic Impact of Beef Cattle Best Management Practices in South Texas: Stocking Strategies during Drought

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    In a drought situation, forage is normally reduced due to lack of adequate moisture. Moreover, the availability of hay may become limited, and hay prices often escalate. Cow-calf producers are faced with the integral decision to maintain their herds and supplemental feed or reduce the herd to minimize feeding requirements and costs. The management decision to maintain versus destock can significantly impact producer profits and financial position. This paper illustrates the financial implications of alternative management stocking strategies in a drought situation optimizing profitability of ranching operations

    Factorized Tree-level Scattering in AdS_4 x CP^3

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    AdS_4/CFT_3 duality relating IIA string theory on AdS_4 x CP^3 to N=6 superconformal Chern-Simons theory provides an arena for studying aspects of integrability in a new potentially exactly solvable system. In this paper we explore the tree-level worldsheet scattering for strings on AdS_4 x CP^3. We compute all bosonic four-, five- and six-point amplitudes in the gauge-fixed action and demonstrate the absence of particle production.Comment: 23 pages, v2. references adde

    The Zamolodchikov-Faddeev algebra for open strings attached to giant gravitons

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    We extend the Zamolodchikov-Faddeev algebra for the superstring sigma model on AdS5ƗS5AdS_{5}\times S^{5}, which was formulated by Arutyunov, Frolov and Zamaklar, to the case of open strings attached to maximal giant gravitons, which was recently considered by Hofman and Maldacena. We obtain boundary SS-matrices which satisfy the standard boundary Yang-Baxter equation.Comment: 22 pages, no figure; added a referenc

    Bio-CAP:a versatile and highly sensitive technique to purify and characterise regions of non-methylated DNA

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    Across vertebrate genomes methylation of cytosine residues within the context of CpG dinucleotides is a pervasive epigenetic mark that can impact gene expression and has been implicated in various developmental and disease-associated processes. Several biochemical approaches exist to profile DNA methylation, but recently an alternative approach based on profiling non-methylated CpGs was developed. This technique, called CxxC affinity purification (CAP), uses a ZF-CxxC (CxxC) domain to specifically capture DNA containing clusters of non-methylated CpGs. Here we describe a new CAP approach, called biotinylated CAP (Bio-CAP), which eliminates the requirement for specialized equipment while dramatically improving and simplifying the CxxC-based DNA affinity purification. Importantly, this approach isolates non-methylated DNA in a manner that is directly proportional to the density of non-methylated CpGs, and discriminates non-methylated CpGs from both methylated and hydroxymethylated CpGs. Unlike conventional CAP, Bio-CAP can be applied to nanogram quantities of genomic DNA and in a magnetic format is amenable to efficient parallel processing of samples. Furthermore, Bio-CAP can be applied to genome-wide profiling of non-methylated DNA with relatively small amounts of input material. Therefore, Bio-CAP is a simple and streamlined approach for characterizing regions of the non-methylated DNA, whether at specific target regions or genome wide

    COMPETITION AMONG HOSPITALS AND ITS MEASUREMENT: THEORY AND A CASE STUDY

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    Our paper provides several insights on the characteristics of the concept of ā€œPoles dā€™Excellence Ruraleā€ (PER) through bilateral comparisons with that of Competitive Pole (CP) and cluster. The concept of PER is a French governmentā€™ initiative designed for the development of rural areas similar to that of the Competitive Pole. We emphasize important particularities of these concepts by analyzing some of their similarities and major differences.Pole dā€™Excellence Rurale, Competitive Pole, cluster, rural development

    Disentangling the drivers of future Antarctic ice loss with a historically calibrated ice-sheet model

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    We use an observationally calibrated ice-sheet model to investigate the future trajectory of the Antarctic ice sheet related to uncertainties in the future balance between sub-shelf melting and ice discharge, on the one hand, and the surface mass balance, on the other. Our ensemble of simulations, forced by a panel of climate models from the sixth phase of the Coupled Model Intercomparison Project (CMIP6), suggests that the ocean will be the primary driver of short-term Antarctic mass loss, initiating ice loss in West Antarctica already during this century. The atmosphere initially plays a mitigating role through increased snowfall, leading to an Antarctic contribution to global mean sea-level rise by 2100 of 6Ā (āˆ’8 to 15)ā€‰cm under a low-emission scenario and 5.5Ā (āˆ’10 to 16)ā€‰cm under a very high-emission scenario. However, under the very high-emission pathway, the influence of the atmosphere shifts beyond the end of the century, becoming an amplifying driver of mass loss as the ice sheet's surface mass balance decreases. We show that this transition occurs when Antarctic near-surface warming exceeds a critical threshold of +7.5ā€‰āˆ˜C, at which the increase in surface runoff outweighs the increase in snow accumulation, a signal that is amplified by the meltā€“elevation feedback. Therefore, under the very high-emission scenario, oceanic and atmospheric drivers are projected to result in a complete collapse of the West Antarctic ice sheet along with significant grounding-line retreat in the marine basins of the East Antarctic ice sheet, leading to a median global mean sea-level rise of 2.75 (6.95)ā€‰m by 2300 (3000). Under a more sustainable socio-economic pathway, we find that the Antarctic ice sheet may still contribute to a median global mean sea-level rise of 0.62 (1.85)ā€‰m by 2300 (3000). However, the rate of sea-level rise is significantly reduced as mass loss is likely to remain confined to the Amundsen Sea Embayment, where present-day climate conditions seem sufficient to commit to a continuous retreat of Thwaites Glacier.</p

    Super-solar metallicity at the position of the ultra-long GRB130925A

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    Over the last decade there has been immense progress in the follow-up of short and long GRBs, resulting in a significant rise in the detection rate of X-ray and optical afterglows, in the determination of GRB redshifts, and of the identification of the underlying host galaxies. Nevertheless, our theoretical understanding on the progenitors and central engines powering these vast explosions is lagging behind, and a newly identified class of `ultra-long' GRBs has fuelled speculation on the existence of a new channel of GRB formation. In this paper we present high signal-to-noise X-shooter observations of the host galaxy of GRB130925A, which is the fourth unambiguously identified ultra-long GRB, with prompt gamma-ray emission detected for ~20ks. The GRB line of sight was close to the host galaxy nucleus, and our spectroscopic observations cover both this region along the bulge/disk of the galaxy, in addition to a bright star-forming region within the outskirts of the galaxy. From our broad wavelength coverage we obtain accurate metallicity and dust-extinction measurements at both the galaxy nucleus, and an outer star-forming region, and measure a super-solar metallicity at both locations, placing this galaxy within the 10-20% most metal-rich GRB host galaxies. Such a high metal enrichment has implications on the progenitor models of both long and ultra-long GRBs, although the edge-on orientation of the host galaxy does not allow us to rule out a large metallicity variation along our line of sight. The spatially resolved spectroscopic data presented in this paper offer important insight into variations in the metal and dust abundance within GRB host galaxies. They also illustrate the need for IFU observations on a larger sample of GRB host galaxies at varies metallicities to provide a more quantitative view on the relation between the GRB circumburst and the galaxy-whole properties.Comment: 9 pages, 3 figures, A&A in press, matches published versio
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