649 research outputs found
Cyclic cycle systems of the complete multipartite graph
In this paper, we study the existence problem for cyclic -cycle
decompositions of the graph , the complete multipartite graph with
parts of size , and give necessary and sufficient conditions for their
existence in the case that
A Comparison of Synovex ONE® Alone to Synovex Choice® Followed by Synovex Plus® as Implant Strategies for Finishing Heifers
A commercial feedlot study utilizing 1,737 crossbred heifers (initial BW 690 lb) compared the effect of two implant strategies [Synovex ONE Feedlot (day 0) or Synovex Choice (day 0) followed by Synovex Plus (day 95)] on performance and carcass characteristics. No differences were observed in carcass weight, final body weight, or gain, but heifers implanted with Synovex ONE Feedlot had slightly greater feed conversion and greater intake than heifers implanted using Synovex Choice/Synovex Plus. Heifers implanted with Synovex Choice/Synovex Plus had lower marbling score and yield grade, higher dressing percentage, and greater loin muscle area compared to heifers implanted with Synovex ONE Feedlot. Cattle implanted with Synovex ONE Feedlot showed a tendency for better quality grading compared to heifers implanted with Synovex Choice/Synovex Plus. These data suggest that implanting heifers with Synovex ONE Feedlot gives comparable growth to heifers implanted with Synovex Choice followed by Synovex Plus, with some changes in fatness when fed equal days
BNNT- Mediated Irreversible Electroporation: It\u27s Potential on Cancer Cells
Irreversible lethal electroporation (IRE) is a new non-thermal ablation modality that uses short pulses of high amplitude static electric fields (up 1000V/cm) to create irreversible pores in the cell membrane, thus, causing cell death. Recently, IRE has emerged as a promising clinical modality for cancer disease treatment. Here, we investigated the responses of tumour human He La cells when subjected to IRE in the presence of BNNTs. These consist of tiny tubes of B and N atoms (arranged in hexagons) with diameters ranging from a 1 to 3 nanometres and lengths \u3c2 μm. BNNTs have attracted wide attention because of their unique electrical properties. We speculate that BNNTs, when interacting with cells exposed to static electrical fields, amplify locally the electric field, leading to cell death. In this work, electroporation assays were performed with a commercial electroporator using the cell-specific protocol suggested by the supplier (exponential decay wave, time constant 20ms) with the specific aim to compare IRE in absence and in presence of BNNTs. We observed that BNNTs have the capacity to decrease substantially the voltage required for IRE. When cells were pulsed at 800V/cm, we observed a 2,2-fold reduction in cell survival in the presence of BNNTs compared to controls. We conclude that the death of the tumour cells exposed to IRE is strongly enhanced in the presence of BNNTs, indicating their potential therapeutic application
X ray based displacement measurement for hostile environments
A new method on noncontacting, high temperature extensometry based on the focus and scanning of x rays is currently under development and shows great promise of overcoming limitations associated with available techniques. The chief advantage is the ability to make undisturbed measurements through stratified or flowing gases, smoke, and flame. The system is based on the ability to focus and scan low energy, hard x rays such as those emanating from copper or molybdenum sources. The x rays are focused into a narrow and intense line image which can be scanned onto targets that fluoresce secondary x ray radiation. The final goal of the system is the ability to conduct macroscopic strain measurements in hostile environments by utilizing two or more fluorescing targets. Current work is limited to displacement measurement of a single target with a resolution of 1.25 micro-m and a target temperature of 1200 C, directly through an open flame. The main advantage of the technique lies in the penetrating nature of x rays which are not affected by the presence of refracting gas layers, smoke, flame, or intense thermal radiation, all of which could render conventional extensometry methods inoperative or greatly compromise their performance
The Seven-sphere and its Kac-Moody Algebra
We investigate the seven-sphere as a group-like manifold and its extension to
a Kac-Moody-like algebra. Covariance properties and tensorial composition of
spinors under are defined. The relation to Malcev algebras is
established. The consequences for octonionic projective spaces are examined.
Current algebras are formulated and their anomalies are derived, and shown to
be unique (even regarding numerical coefficients) up to redefinitions of the
currents. Nilpotency of the BRST operator is consistent with one particular
expression in the class of (field-dependent) anomalies. A Sugawara construction
is given.Comment: 22 pages. Macropackages used: phyzzx, epsf. Three epsf figure files
appende
Spectroscopy and dissociative recombination of the lowest rotational states of H3+
The dissociative recombination of the lowest rotational states of H3+ has
been investigated at the storage ring TSR using a cryogenic 22-pole
radiofrequency ion trap as injector. The H3+ was cooled with buffer gas at ~15
K to the lowest rotational levels, (J,G)=(1,0) and (1,1), which belong to the
ortho and para proton-spin symmetry, respectively. The rate coefficients and
dissociation dynamics of H3+(J,G) populations produced with normal- and para-H2
were measured and compared to the rate and dynamics of a hot H3+ beam from a
Penning source. The production of cold H3+ rotational populations was
separately studied by rovibrational laser spectroscopy using chemical probing
with argon around 55 K. First results indicate a ~20% relative increase of the
para contribution when using para-H2 as parent gas. The H3+ rate coefficient
observed for the para-H2 source gas, however, is quite similar to the H3+ rate
for the normal-H2 source gas. The recombination dynamics confirm that for both
source gases, only small populations of rotationally excited levels are
present. The distribution of 3-body fragmentation geometries displays a broad
part of various triangular shapes with an enhancement of ~12% for events with
symmetric near-linear configurations. No large dependences on internal state or
collision energy are found.Comment: 10 pages, 9 figures, to be published in Journal of Physics:
Conference Proceeding
Anisotropic fragmentation in low-energy dissociative recombination
On a dense energy grid reaching up to 75 meV electron collision energy the
fragmentation angle and the kinetic energy release of neutral dissociative
recombination fragments have been studied in a twin merged beam experiment. The
anisotropy described by Legendre polynomials and the extracted rotational state
contributions were found to vary on a likewise narrow energy scale as the
rotationally averaged rate coefficient. For the first time angular dependences
higher than 2 order could be deduced. Moreover, a slight anisotropy at
zero collision energy was observed which is caused by the flattened velocity
distribution of the electron beam.Comment: 8 pages, 4 figures; The Article will be published in the proceedings
of DR 2007, a symposium on Dissociative Recombination held in Ameland, The
Netherlands (18.-23. July 2008); Reference 19 has been published meanwhile in
S. Novotny, PRL 100, 193201 (2008
Comparison of Performance and Economics of a Long-yearling and Calf-fed System
Performance and economics of calf feeding and feeding long-yearlings was compared from University of Nebraska research conducted from 1996 to 2004. All calves in these studies were spring born and purchased the subsequent fall. The heaviest calves (292 ± 5 kg) were placed into the feedlot and fed an average of 168 d (calf-feds), whereas the lighter calves (239 ± 5 kg) were placed into a long-yearling system consisting of corn residue grazing followed by summer grazing before entering the feedlot for finishing. Long-yearlings were fed in the feedlot for an average of 90 d. At the beginning of the finishing period, long-yearlings were 143 kg heavier than calf-feds (P \u3c 0.01). Although daily DMI was greater for long-yearlings (P \u3c 0.01), calf-feds consumed more total DM during finishing (P \u3c 0.01). Long-yearlings had greater ADG compared with calf-feds during finishing (P \u3c 0.01); however, calf-feds were 18.7% more efficient (P \u3c 0.01). Long-yearlings were 38 kg heavier (P \u3c 0.01) than calf-feds and had 24 kg heavier hot carcass weight (P \u3c 0.01). Quality grade was not affected by production system (P \u3e 0.10); however, calf-feds had 0.15 cm greater fat thickness (P \u3c 0.01). Long-yearlings were more profitable than calf-feds (P \u3c 0.01) due to lower feed cost (P \u3c 0.01), yardage (P \u3c 0.01), and initial animal cost (P \u3c 0.01). However, long-yearlings had higher interest cost (P \u3c 0.01) and total cost (P = 0.02). Long-yearlings produced greater final BW leading to an improvement in profitability compared with calf-feds
Electron-ion recombination of Mg6 + forming Mg5 + and of Mg7 + forming Mg6 + : laboratory measurements and theoretical calculations
We have measured electron–ion recombination for C-like Mg6+ forming Mg5+, and for B-like Mg7+ forming Mg6+. These studies were performed using a merged electron–ion beam arrangement at the TSR heavy ion storage ring located in Heidelberg, Germany. Both primary ions have metastable levels with significant lifetimes. Using a simple cascade model we estimate the population fractions in these metastable levels. For the Mg6+ results, we find that the majority of the stored ions are in a metastable level, while for Mg7+ the metastable fraction is insignificant. We present the Mg6+ merged beams recombination rate coefficient for DR via N = 2 → N = 2 core electron excitations (ΔN = 0 DR) and for Mg7+ via 2 → 2 and 2 → 3 core excitations. Taking the estimated metastable populations into account, we compare our results to state-of-the-art multiconfiguration Breit–Pauli theoretical calculations. Significant differences are found at low energies where theory is known to be unreliable. Moreover, for both ions we observe a discrepancy between experiment and theory for ΔN = 0 DR involving capture into high-n Rydberg levels and where the stabilization is primarily due to a radiative transition of the excited core electron. This is consistent with previous DR experiments on M-shell iron ions which were performed at TSR. The large metastable content of the Mg6+ ion beam precludes generating a plasma recombination rate coefficient (PRRC). However, this is not an issue for Mg7+ and we present an experimentally derived Mg7+ PRRC for plasma temperatures from 400 K to 107 K with an estimated uncertainty of less than 27% at a 90% confidence level. We also provide a fit to our experimentally derived PRRC for use in plasma modeling codes
A restatement of the natural science evidence base concerning grassland management, grazing livestock and soil carbon storage
Approximately a third of all annual greenhouse gas emissions globally are directly or indirectly associated with the food system, and over a half of these are linked to livestock production. In temperate oceanic regions, such as the UK, most meat and dairy is produced in extensive systems based on pasture. There is much interest in the extent to which such grassland may be able to sequester and store more carbon to partially or completely mitigate other greenhouse gas emissions in the system. However, answering this question is difficult due to context-specificity and a complex and sometimes inconsistent evidence base. This paper describes a project that set out to summarize the natural science evidence base relevant to grassland management, grazing livestock and soil carbon storage potential in as policy-neutral terms as possible. It is based on expert appraisal of a systematically assembled evidence base, followed by a wide stakeholders engagement. A series of evidence statements (in the appendix of this paper) are listed and categorized according to the nature of the underlying information, and an annotated bibliography is provided in the electronic supplementary material
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