1,663 research outputs found
Development of an index to rank dairy females on expected lifetime profit
peer-reviewedThe objective of this study was to develop an index to rank dairy females on expected profit for the remainder of their lifetime, taking cognizance of both additive and nonadditive genetic merit, permanent environmental effects, and current states of the animal including the most recent calving date and cow parity. The cow own worth (COW) index is intended to be used for culling the expected least profitable females in a herd, as well as inform purchase and pricing decisions for trading of females. The framework of the COW index consisted of the profit accruing from (1) the current lactation, (2) future lactations, and (3) net replacement cost differential. The COW index was generated from estimated performance values (sum of additive genetic merit, nonadditive genetic merit, and permanent environmental effects) of traits, their respective net margin values, and transition probability matrices for month of calving, survival, and somatic cell count; the transition matrices were to account for predicted change in a cow’s state in the future. Transition matrices were generated from 3,156,109 lactation records from the Irish national database between the years 2010 and 2013. Phenotypic performance records for 162,981 cows in the year 2012 were used to validate the COW index. Genetic and permanent environmental effects (where applicable) were available for these cows from the 2011 national genetic evaluations and used to calculate the COW index and their national breeding index values (includes only additive genetic effects). Cows were stratified per quartile within herd, based on their COW index value and national breeding index value. The correlation between individual animal COW index value and national breeding index value was 0.65. Month of calving of the cow in her current lactation explained 18% of the variation in the COW index, with the parity of the cow explaining an additional 3 percentage units of the variance in the COW index. Females ranking higher on the COW index yielded more milk and milk solids and calved earlier in the calving season than their lower ranking contemporaries. The difference in phenotypic performance between the best and worst quartiles was larger for cows ranked on COW index than cows ranked on the national breeding index. The COW index is useful to rank females before culling or purchasing decisions on expected profit and is complementary to the national breeding index, which identifies the most suitable females for breeding replacements
4-Benzyl-N-methylpiperazine-1-carbothioamide
The asymmetric unit in the title thiourea derivative, C13H19N3S, comprises three independent molecules (A, B and C). The thiourea groups are superimposable for the three molecules, but there are significant conformational differences. Molecules A and B are approximate mirror images of each other, and molecule C has an intermediate conformation. The dihedral angles between the thiourea groups and the phenyl rings are 52.10 (5), 63.29 (5) and 66.46 (6)° in molecules A, B and C, respectively. Each independent molecule self-associates into a supramolecular chain along [100] via N—H⋯S hydrogen bonds. Molecules of A and B assemble into layers four molecules thick in the ac plane via C—H⋯S and C—H⋯π interactions. Molecules of C self-assemble into layers in the ac plane via C—H⋯S interactions. The layers stack along the b axis with no specific interactions between them
Device and method for measuring thermal conductivity of thin films
A device and method are provided for measuring the thermal conductivity of rigid or flexible, homogeneous or heterogeneous, thin films between 50 .mu.m and 150 .mu.m thick with relative standard deviations of less than five percent. The specimen is sandwiched between like material, highly conductive upper and lower slabs. Each slab is instrumented with six thermocouples embedded within the slab and flush with their corresponding surfaces. A heat source heats the lower slab and a heat sink cools the upper slab. The heat sink also provides sufficient contact pressure onto the specimen. Testing is performed within a vacuum environment (bell-jar) between 10.sup.-3 to 10.sup.-6 Torr. An anti-radiant shield on the interior surface of the bell-jar is used to avoid radiation heat losses. Insulation is placed adjacent to the heat source and adjacent to the heat sink to prevent conduction losses. A temperature controlled water circulator circulates water from a constant temperature bath through the heat sink. Fourier's one-dimensional law of heat conduction is the governing equation. Data, including temperatures, are measured with a multi-channel data acquisition system. On-line computer processing is used for thermal conductivity calculations
2,6-Bis[(S)-1-phenylethyl]-1H,5H-pyrrolo[3,4-f]isoindole-1,3,5,7(2H,6H)-tetrone
In the title compound, C26H20N2O4, the central isoindole core is almost planar (r.m.s. deviation = 0.043 Å). The phenyl rings lie to either side of the plane [dihedral angles = 88.64 (5) and 67.74 (6)°] and the dihedral angle between the phenyl rings is 63.39 (7)°. In the crystal, molecules are linked by C—H⋯O interactions; notably, one carbonyl O atom accepts three such bonds
1-Acetyl-4-(phenylsulfanyl)imidazolidin-2-one
The five-membered ring in the title imidazolidinone derivative, C11H12N2O2S, adopts an envelope conformation with the S-bound C atom being the flap atom. Overall, the molecule has a U-shaped conformation as both rings are folded towards each other [dihedral angle = 31.66 (6)°]. An eight-membered amide {⋯HNCO}2 synthon leads to hydrogen-bonded dimeric aggregates in the crystal: these are additionally linked by C—H⋯π interactions
Quantum Foam and Topological Strings
We find an interpretation of the recent connection found between topological
strings on Calabi-Yau threefolds and crystal melting: Summing over statistical
mechanical configuration of melting crystal is equivalent to a quantum
gravitational path integral involving fluctuations of Kahler geometry and
topology. We show how the limit shape of the melting crystal emerges as the
average geometry and topology of the quantum foam at the string scale. The
geometry is classical at large length scales, modified to a smooth limit shape
dictated by mirror geometry at string scale and is a quantum foam at area
scales g_s \alpha'.Comment: 55 page
On the Complexity of Query Result Diversification
Query result diversification is a bi-criteria optimization problem for ranking query results. Given a database D, a query Q and a positive integer k, it is to find a set of k tuples from Q(D) such that the tuples are as relevant as possible to the query, and at the same time, as diverse as possible to each other. Subsets of Q(D) are ranked by an objective function defined in terms of relevance and diversity. Query result diversification has found a variety of applications in databases, information retrieval and operations research. This paper studies the complexity of result diversification for relational queries. We identify three problems in connection with query result diversification, to determine whether there exists a set of k tuples that is ranked above a bound with respect to relevance and diversity, to assess the rank of a given k-element set, and to count how many k-element sets are ranked above a given bound. We study these problems for a variety of query languages and for three objective functions. We establish the upper and lower bounds of these problems, all matching, for both combined complexity and data complexity. We also investigate several special settings of these problems, identifying tractable cases. 1
Chiral symmetry breaking, color superconductivity and color neutral quark matter: a variational approach
We investigate the vacuum realignment for chiral symmetry breaking and color
superconductivity at finite density in Nambu-Jona-Lasinio model in a
variational method. The treatment allows us to investigate simultaneous
formation of condensates in quark antiquark as well as in diquark channels. The
methodology involves an explicit construction of a variational ground state and
minimisation of the thermodynamic potential. Color and electric charge
neutrality conditions are imposed through introduction of appropriate chemical
potentials. Color and flavor dependent condensate functions are determined
through minimisation of the thermodynamic potential. The equation of state is
calculated. Simultaneous existence of a mass gap and superconducting gap is
seen in a small window of quark chemical potential within the model when charge
neutrality conditions are not imposed. Enforcing color and electric charge
neutrality conditions gives rise to existence of gapless superconducting modes
depending upon the magnitude of the gap and the difference of the chemical
potentials of the condensing quarks.Comment: 13 pages, 6 figures,to appear in Phys. Rev.
f [N pi N]: from quarks to the pion derivative coupling
We study the N pi N coupling, in the framework of a QCD-inspired confining
Nambu-Jona-Lasinio model. A simple relativistic confining and instantaneous
quark model is reviewed. The Salpeter equation for the nucleon and the boosted
pion is solved. The f [n pi n] and f[n pi Delta] couplings are calculated and
they turn out to be reasonably good. The sensibility of f[n pi n] and f[n pi
Delta] to confinement, chiral symmetry breaking and Lorentz invariance is
briefly discussed.Comment: 30 pages in LaTex RevTex, 6 postscript figure
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