On multiplicity-free skew characters and the Schubert Calculus

In this paper we classify the multiplicity-free skew characters of the symmetric group. Furthermore we show that the Schubert calculus is equivalent to that of skew characters in the following sense: If we decompose the product of two Schubert classes we get the same as if we decompose a skew character and replace the irreducible characters by Schubert classes of the `inverse' partitions (Theorem 4.2).Comment: 14 pages, to appear in Annals. Comb. minor changes from v1 to v2 as suggested by the referees, Example 3.4 inserted so numeration changed in section

Automated ice-core layer-counting with strong univariate signals

We present an automated process for determining the annual layer chronology of an ice-core with a strong annual signal, utilising the hydrogen peroxide record from an Antarctic Peninsula ice-core as a test signal on which to count annual cycles and explain the methods. The signal is de-trended and normalised before being split into sections with a deterministic cycle count and those that need more attention. Possible reconstructions for the uncertain sections are determined which could be used as a visual aid for manual counting, and a simple method for assigning probability measures to each reconstruction is discussed. The robustness of this process is explored by applying it to versions of two different chemistry signals from the same stretch of the NGRIP (North Greenland Ice Core Project) ice-core, which shows more variation in annual layer thickness, with and without thinning to mimic poorer quality data. An adapted version of these methods is applied to the more challenging non-sea-salt sulphur signal from the same Antarctic Peninsula core from which the hydrogen peroxide signal was taken. These methods could readily be adapted for use on much longer datasets, thereby reducing manual effort and providing a robust automated layer-counting methodology

Geology of the Huntly and Turriff districts : sheet description for the 1:50 000 geological sheets 86W (Huntly) and 86E (Turriff) (Scotland)

This report summarises the results of detailed geological remapping and related studies under-taken by the Geological Survey in the Huntly and Turriff districts of North-east Scotland. It pro-vides an account of the geology to accompany the published 1:50 000 geological maps sheets 86W (Huntly) and 86E (Turriff). The districts occupy a tract of generally rolling country, which ranges from about 50 to 200 m above sea level in its eastern part, to more elevated hilly country, commonly reaching over 300 m and 400 m above OD, in its western and southern parts. The drainage is dominated by the sinuous incised valley of the River Deveron and its main tributar-ies, the rivers Isla and Bogie, except for the southern part of the Turriff district, which is drained by the headwaters of the River Ythan. Agriculture and forestry are the dominant economic ac-tivities, with tourism and whisky distilling also significant. The Huntly and Turriff districts are underlain mainly by Dalradian metasedimentary rocks of Neoproterozoic age that have been strongly deformed and metamorphosed during the Grampian event of the Caledonian Orogeny. The Dalradian rocks have been intruded by igneous intrusions that range from large plutons to small pods and dykes. Granite sheets and pods were emplaced at about 600 million years (Ma), followed later by small ultramafic and mafic bodies. However, the main intrusive igneous event occurred in the Early to Mid Ordovician at 474 to 470 Ma, coeval with the Grampian event. It resulted in the emplacement of mafic and ultramafic plutons, com-monly zoned; the Insch Pluton includes monzonites and syenites in its upper zone. Dioritic and granitic bodies are associated with the plutons. The major structural feature is the north-north-east-trending Portsoy Shear Zone, which traverses the Huntly district. This steeply easterly dipping zone is coincident with a major regional linea-ment, which separates stratigraphically discrete packages of Dalradian rocks with different tec-tonometamorphic histories. The shear zone has also facilitated and in part controlled the emplacement of the Huntly and Knock mafic-ultramafic plutons. The Dalradian metasedimen-tary rocks contain both Buchan and Barrovian metamorphic zonal assemblages. Folding and shearing have caused local repetition of lithological units, but overall the Dalradian sequence be-comes younger eastwards until the broad hinge of the regional Turriff Syncline is reached in the central part of that district. Here, the youngest Dalradian rocks are exposed and metamorphic grade is low (biotite grade). Farther east older Dalradian rocks again crop out and the Buchan metamorphic isograds are re-crossed such that the rocks contain andalusite and sillimanite. Following the Grampian orogenic event the area was uplifted, and during the Early Devonian fluvial and lacustrine Old Red Sandstone rocks were deposited in the northerly trending fault-bounded basins, namely the Turriff and Rhynie basins. In Strath Bogie a basaltic andesite lava unit linked to the Rhynie chert occurs within the Rhynie Basin succession. Subsequently, a Mid-dle Devonian conglomerate-dominated sequence, linked to the Orcadian Lake farther north, was deposited unconformably on the older succession in the Turriff Basin. In the Turriff district deep Tertiary weathering profiles and local fluvial sands and gravels are preserved, testifying to only limited erosion by the later Quaternary glaciations. The Devensian glacial and postglacial history of the districts was dominated by an ice sheet derived from the highland areas farther to the south-west. The related glacial and postglacial superficial deposits form a pervasive if generally thin cover over much of the bedrock. Till derived from the Moray Firth is present in the north-eastern part of the Turriff district. Eastward migration of glacial meltwater gave rise to channels that in places have significantly influenced development of the Holocene fluvial drainage pattern. The Huntly district has been the focus of several periods of exploration since 1970 for platinum group elements, copper and nickel linked mainly to the mafic-ultramafic plutons and their meta-morphic aureoles. The limited drilling and more extensive ground magnetic surveys, in combina-tion with geochemical studies and gravity modelling, have provided detailed information as to the nature, distribution and origin of prospective areas. No economic deposits have been deline-ated to date. However, this BGS report and the geological maps provide a sound foundation for existing and any future commercial and/or conservation-related developments

Muscle Development and Lineage-Specific Expression of CiMDF, the MyoD-Family Gene of Ciona intestinalis

AbstractThe expression pattern of CiMDF, the MyoD-family gene of Ciona intestinalis, was analyzed in unmanipulated and microsurgically derived partial embryos. CiMDF encodes two transcripts during development (coding for distinct proteins), the smaller of which, CiMDFa, was detected in maternal RNA. Zygotic activity of CiMDF initiated in cleaving embryos of 32–64 cells. Both CiMDFa and CiMDFb transcripts were detected at this time; however, CiMDFa accumulated more rapidly before declining in abundance such that, by the early tail-formation stage, CiMDFb was more prevalent. Microsurgical isolations of various lineage blastomeres from the eight-cell stage were used to analyze CiMDF expression in the two embryonic lineages that give rise to larval tail muscle—autonomously specified primary cells and conditionally specified secondary cells. CiMDFa and CiMDFb transcripts were detected in both lineages, suggesting that neither functioned in a lineage-specific manner. The data also demonstrated that CiMDF expression was autonomous in the primary lineage (i.e., cells derived from the B4.1 blastomeres) and correlated with histospecific differentiation of muscle. In the secondary lineage (i.e., cells derived from the A4.1 and b4.2 blastomeres), CiMDF expression was conditional and, as in the primary lineage, correlated with muscle differentiation. These experiments reveal similar patterns of CiMDF activity in the primary and secondary muscle lineages and imply a requirement for the expression of this gene in both lineages during larval tail muscle development

Hurricanes, fertility, and family structure:a study of early 20th century Jamaica

This study investigates the impact of hurricanes on fertility and the role of family structure in early 20th century Jamaica. Importantly, this was a time period in which there were no storm warnings or other formal disaster mitigation policies in place, allowing one to arguably identify the causal effect of storms on births without any policy interference. To this end, historical hurricane tracks and an exhaustive register of births are used to create a parish level monthly data set on births and hurricane destruction for the period 1901 to 1929. The regression analysis reveals that hurricanes impact excess births for close to 2 years after the event, with the average damaging storm causing a reduction in births of around 13%. Most of the negative effect is due to lower post-storm fertility rather than a fall in births by women affected while pregnant. There is no evidence that the fall in births was driven by fertile females dying as a result of the hurricane. Similarly, there was no discernible differential impact between single mother and two parent registered births, where the impact on the latter appears to be driven by non-marital conjugal unions

Trees over Infinite Structures and Path Logics with Synchronization

We provide decidability and undecidability results on the model-checking problem for infinite tree structures. These tree structures are built from sequences of elements of infinite relational structures. More precisely, we deal with the tree iteration of a relational structure M in the sense of Shelah-Stupp. In contrast to classical results where model-checking is shown decidable for MSO-logic, we show decidability of the tree model-checking problem for logics that allow only path quantifiers and chain quantifiers (where chains are subsets of paths), as they appear in branching time logics; however, at the same time the tree is enriched by the equal-level relation (which holds between vertices u, v if they are on the same tree level). We separate cleanly the tree logic from the logic used for expressing properties of the underlying structure M. We illustrate the scope of the decidability results by showing that two slight extensions of the framework lead to undecidability. In particular, this applies to the (stronger) tree iteration in the sense of Muchnik-Walukiewicz.Comment: In Proceedings INFINITY 2011, arXiv:1111.267

Variations of radiocarbon in tree rings: southern hemisphere offset preliminary results

The Queen's University of Belfast, Northern Ireland and University of Waikato, Hamilton, New Zealand radiocarbon laboratories have undertaken a series of high-precision measurements on decadal samples of dendrochronologically dated oak (Quercus patrea) and cedar (Libocedrus bidwillii) from Great Britain and New Zealand, respectively. The results show a real atmospheric offset of 3.4 ± 0.6% (27.2 ± 4.7 ¹⁴C yr) between the two locations for the interval AD 1725 to AD 1885, with the Southern Hemisphere being depleted in ¹⁴C. This result is less than the value currently used to correct Southern Hemisphere calibrations, possibly indicating a gradient in Δ¹⁴C within the Southern Hemisphere

Cost Analysis and Water Conservation Potential of Irrigation Technologies in the Texas Panhandle Water Planning Area

Six irrigation systems are analyzed considering cost and potential water savings. The investment cost of furrow and drip is $115,800 and$260,120, respectively. The cost of quarter mile pivot ranges from $59,000 to$64,000. Per ac-in variable pumping cost ranges $9.96 to$14.86 assuming natural gas price $7.00 per MCF.Irrigation Technology, Ground Water Planning, Texas Panhandle, Water Conservation, Ogallala, Agribusiness, Environmental Economics and Policy, Farm Management, Production Economics, Resource /Energy Economics and Policy,

Switch from sexual to parthenogenetic reproduction in a zebra shark

Parthenogenesis is a natural form of asexual reproduction in which embryos develop in the absence of fertilisation. Most commonly found in plants and invertebrate organisms, an increasing number of vertebrate species have recently been reported employing this reproductive strategy. Here we use DNA genotyping to report the first demonstration of an intra-individual switch from sexual to parthenogenetic reproduction in a shark species, the zebra shark Stegostoma fasciatum. A co-housed, sexually produced daughter zebra shark also commenced parthenogenetic reproduction at the onset of maturity without any prior mating. The demonstration of parthenogenesis in these two conspecific individuals with different sexual histories provides further support that elasmobranch fishes may flexibly adapt their reproductive strategy to environmental circumstances

Hydrodynamic obstruction to bubble expansion

We discuss a hydrodynamic obstruction to bubble wall acceleration during a cosmological first-order phase transition. The obstruction results from the heating of the plasma in the compression wave in front of the phase transition boundary. We provide a simple criterion for the occurrence of the obstruction at subsonic bubble wall velocity in terms of the critical temperature, the phase transition temperature, and the latent heat of the model under consideration. The criterion serves as a sufficient condition of subsonic bubble wall velocities as required by electroweak baryogenesis.Comment: 18 pages, 4 figures; comments and reference added, published versio