3,314 research outputs found
Modelling effects of an asphalt road at a dike crest on dike cover erosion onset during wave overtopping
Structures integrated in a grass-covered dike may increase erosion development. Currently, safety assessment methods for flood defences are only applicable for a conventional grass-covered dike and the effects of structures on dike cover erosion are poorly understood. Since many dikes have a road on top, it is important to study the effect of such a road structure on erosion onset during wave overtopping. To investigate this effect, a coupled hydrodynamic–eroison model was developed. The erosion onset caused by overtopping waves was predicted by combining the time-varying bed shear stresses from the hydrodynamic model with a depth-dependent erosion model. The results show that roads on top of a dike increase the erosion of the neighbouring grass cover. This increase in erosion may have a negative impact on dike stability. Therefore, we recommend considering effects of constructions on top of dike profiles during safety assessments. Explicitly, consideration of the roughness transitions in the safety assessments of dikes is recommende
Rendimientos productivos y calidad de la canal de hembras, machos castrados quirurgicamente y machos inmunocastrados procedentes de lĂneas paternas duroc y pietrain
Tradicionalmente la castraciĂłn quirĂşrgica ha sido la práctica más habitual en la producciĂłn de cerdo blanco destinado a la industria de productos cárnicos curados. La castraciĂłn quirĂşrgica conlleva un empeoramiento de los rendimientos productivos y penaliza el bienestar animal. Como alternativa ha surgido la inmunizaciĂłn de los cerdos contra el factor de liberaciĂłn de la gonadotropina (GnRH) (FĂ brega et al., 2010). La inmunocastraciĂłn suprime la funciĂłn testicular (Zamaratskaia et al., 2008) y reduce la producciĂłn de androsterona (Dunshea et al., 2001) y escatol (Matthews et al., 2000) asĂ como la agresividad (Jaros et al., 2005). Por tanto, la inmunocastraciĂłn puede ser una alternativa a la castraciĂłn fĂsica en situaciones comerciales. Por otro lado, para la obtenciĂłn de productos curados se precisan canales con más grasa y mayor proporciĂłn de partes nobles que para productos frescos, por lo que se utilizan estrategias como aumentar el peso al sacrificio o el cruce con lĂneas paternas especĂficas. El objetivo de este estudio fue evaluar el rendimiento productivo y la calidad de la canal de hembras enteras (HE), machos castrados (MC) y machos inmunocastrados (MI) procedentes de genĂ©ticas paternas Duroc (DU) y Pietrain (PI) con un peso al sacrificio de 134 kg
Partial Dynamical Symmetry in the Symplectic Shell Model
We present an example of a partial dynamical symmetry (PDS) in an interacting
fermion system and demonstrate the close relationship of the associated
Hamiltonians with a realistic quadrupole-quadrupole interaction, thus shedding
new light on this important interaction. Specifically, in the framework of the
symplectic shell model of nuclei, we prove the existence of a family of
fermionic Hamiltonians with partial SU(3) symmetry. We outline the construction
process for the PDS eigenstates with good symmetry and give analytic
expressions for the energies of these states and E2 transition strengths
between them. Characteristics of both pure and mixed-symmetry PDS eigenstates
are discussed and the resulting spectra and transition strengths are compared
to those of real nuclei. The PDS concept is shown to be relevant to the
description of prolate, oblate, as well as triaxially deformed nuclei.
Similarities and differences between the fermion case and the previously
established partial SU(3) symmetry in the Interacting Boson Model are
considered.Comment: 9 figure
Deformations of conformal theories and non-toric quiver gauge theories
We discuss several examples of non-toric quiver gauge theories dual to
Sasaki-Einstein manifolds with U(1)^2 or U(1) isometry. We give a general
method for constructing non-toric examples by adding relevant deformations to
the toric case. For all examples, we are able to make a complete comparison
between the prediction for R-charges based on geometry and on quantum field
theory. We also give a general discussion of the spectrum of conformal
dimensions for mesonic and baryonic operators for a generic quiver theory; in
the toric case we make an explicit comparison between R-charges of mesons and
baryons.Comment: 51 pages, 12 figures; minor corrections in appendix B, published
versio
The Uncertainty in Newton's Constant and Precision Predictions of the Primordial Helium Abundance
The current uncertainty in Newton's constant, G_N, is of the order of 0.15%.
For values of the baryon to photon ratio consistent with both cosmic microwave
background observations and the primordial deuterium abundance, this
uncertainty in G_N corresponds to an uncertainty in the primordial 4He mass
fraction, Y_P, of +-1.3 x 10^{-4}. This uncertainty in Y_P is comparable to the
effect from the current uncertainty in the neutron lifetime, which is often
treated as the dominant uncertainty in calculations of Y_P. Recent measurements
of G_N seem to be converging within a smaller range; a reduction in the
estimated error on G_N by a factor of 10 would essentially eliminate it as a
source of uncertainty in the calculation of the primordial 4He abundance.Comment: 3 pages, no figures, fixed typos, to appear in Phys. Rev.
Performance and comparability of laboratory methods for measuring ferritin concentrations in human serum or plasma: A systematic review and meta-analysis
Background Different laboratory methods are used to quantify ferritin concentrations as a marker of iron status. A systematic review was undertaken to assess the accuracy and comparability of the most used methods for ferritin detection. Methods and findings National and regional databases were searched for prospective, retrospective, sectional, longitudinal and case-control studies containing the characteristics and performance of at least one method for serum/plasma ferritin determinations in humans published to date. The analysis included the comparison between at least 2 methods detailing: sensitivity, precision, accuracy, predictive values, inter-methods adjustment, and use of international reference materials. Pooled method performance was analyzed for each method and across methods. Outcomes Search strategy identified 11893 records. After de-duplication and screening 252 studies were assessed, including 187 studies in the qualitative analysis and 148 in the meta-analysis. The most used methods included radiometric, nonradiometric and agglutination assays. The overall within-run imprecision for the most reported ferritin methods was 6.2±3.4% (CI 5.69–6.70%; n = 171), between-run imprecision 8.9±8.7% (CI 7.44–10.35%; n = 136), and recovery rate 95.6% (CI 91.5–99.7%; n = 94). The pooled regression coefficient was 0.985 among all methods analyzed, and 0.984 when comparing nonradiometric and radiometric methods, without statistical differences in ferritin concentration ranging from 2.3 to 1454 µµg/L. Conclusion The laboratory methods most used to determine ferritin concentrations have comparable accuracy and performance. Registered in PROSPERO CRD42016036222
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