8,983 research outputs found

    Feeding Programs for Newly Arrived or Recently Weaned Calves

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    Fall is a stressful time for calves. They are generally weaned at this time. Following weaning, they are often transported or moved to a sale barn or unfamiliar facility. Upon arrival, they may be mixed with other cattle, subjected to processing and forced to eat unfamiliar feeds. In addition, all of these stresses may be compounded by foul weather. To combat the negative impacts of stress cattlemen should strive to get new calves on feed as rapidly as possible. Proper nutrition and a consistent health program are essential when starting calves on feed. Proper nutrition is important from two standpoints. First, the success of any health program is highly dependant on the nutritionals status of the calf. In order for the immune system of the calf to form antibodies in response to vaccination programs, sufficient protein, energy vitamins and minerals must be available. The second reason is more obvious. The calf simply needs to consume feed in order to grow and thrive. Ownership and facility costs are generally high. Feeder cattle need to gain weight in order to make money for cattlemen. Newly arrived or recently weaned calves do not readily eat upon arrival in a feedlot. Texas data (Hutcheson, 1980) suggests that a surprisingly high percentage of cattle do not eat during the first few days in the feedlot. Table 1 shows that on day one in the feedlot, only 21.7% of the cattle eat. On day three, over 40% of the cattle will not eat. On seven, 30% of the cattle will not eat. And on day 10, an average of 15% of the cattle will not eat. These data suggest that getting cattle started on feed is a major problem. Three problems need to be addressed in order to get cattle started on feed. First, recently weaned or newly arrived cattle will generally not recognize the feed bunk and may not recognize water troughs. Second, new cattle may not recognize the feed that the producer wishes to feed him. Finally, feed intake by new cattle will likely be low due to stress. The remaining section of this paper focus on managing around these problems. Additional sections include discussions of feed additives, commercial receiving, or weaning rations and health programs

    Explicit lower and upper bounds on the entangled value of multiplayer XOR games

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    XOR games are the simplest model in which the nonlocal properties of entanglement manifest themselves. When there are two players, it is well known that the bias --- the maximum advantage over random play --- of entangled players can be at most a constant times greater than that of classical players. Recently, P\'{e}rez-Garc\'{i}a et al. [Comm. Math. Phys. 279 (2), 2008] showed that no such bound holds when there are three or more players: the advantage of entangled players over classical players can become unbounded, and scale with the number of questions in the game. Their proof relies on non-trivial results from operator space theory, and gives a non-explicit existence proof, leading to a game with a very large number of questions and only a loose control over the local dimension of the players' shared entanglement. We give a new, simple and explicit (though still probabilistic) construction of a family of three-player XOR games which achieve a large quantum-classical gap (QC-gap). This QC-gap is exponentially larger than the one given by P\'{e}rez-Garc\'{i}a et. al. in terms of the size of the game, achieving a QC-gap of order N\sqrt{N} with N2N^2 questions per player. In terms of the dimension of the entangled state required, we achieve the same (optimal) QC-gap of N\sqrt{N} for a state of local dimension NN per player. Moreover, the optimal entangled strategy is very simple, involving observables defined by tensor products of the Pauli matrices. Additionally, we give the first upper bound on the maximal QC-gap in terms of the number of questions per player, showing that our construction is only quadratically off in that respect. Our results rely on probabilistic estimates on the norm of random matrices and higher-order tensors which may be of independent interest.Comment: Major improvements in presentation; results identica

    Obstetric and Perinatal Outcomes in Type 1 Diabetic Pregnancies: A large, population-based study

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    The aim of this epidemiological study was to elucidate whether in recent years, obstetric and perinatal outcomes in pregnancies complicated by type 1 diabetes (T1DM) have improved or not. The objective was also to identify possible risk factors for adverse outcome for the mother, fetus and the newborn. All studies (Ī™-Ī™V) included in this thesis were based on national data from the Swedish Medical Birth Registry, during the time period 1991-2007. In 5,089 type 1 diabetic pregnancies and 1.2 million controls we found significantly increased risks of all adverse outcomes in women with T1DM: adjusted odds ratios: severe preeclampsia: 4.47 (3.77-5.31), Caesarean delivery: 5.31 (4.97-5.69), stillbirth: 3.34 (2.46- 4.55), perinatal mortality: 3.29 (2.50-4.33), major malformations: 2.50 (2.13-2.94) and large for gestational age: LGA (birth weight ā‰„ +2 SD): 11.45 (10.61-12.36) (study Ī™). The markedly elevated odds of an LGA outcome inspired us to characterize in more detail the distribution of birth size in a large national cohort of T1DM offspring (study Ī™Ī™ n=3,705) and to investigate if disproportionate body composition was associated with increased risk of perinatal complications (study Ī™Ī™Ī™ n=3,517). Percentiles for birth weight (BW), birth length (BL) and head circumference (HC) were formed based on data from non-diabetic pregnancies and standard deviation scores (SDS) were calculated for BW, BL and HC. The ponderal index (PI: BW in grams/(BL in cm) Ā³ was used as a proxy for body proportionality and fat mass and we defined disproportionate/overweight LGA as infants with a BW and PI ā‰„90th percentile for gestational age and gender. The distributions of BW, BL and HC were all unimodal but significantly shifted to the right of the normal reference. The distribution for BW was most markedly shifted to the right. 47% were LGA with a BW ā‰„90th adjusted percentile. The mean ponderal index (PI) was significantly increased and 46% of LGA infants were disproportionate with a PI ā‰„90th percentile and thus overweight at birth. A novel and unexpected finding was that fetal macrosomia was more pronounced in preterm and female infants (study Ī™Ī™). Surprisingly, neonatal outcome was independent of body proportionality in appropriate for gestational age (AGA) and LGA infants. The risk of adverse outcome was significantly increased in LGA compared with AGA infants born at term (study Ī™Ī™Ī™). There was a significant interaction between gestational age and body weight with prematurity overriding LGA as a risk factor for neonatal morbidity in moderately preterm infants. In study Ī™V, we examined the risk of adverse outcome in relation to pre-pregnancy body mass index in a national cohort of 3,457 T1DM pregnancies compared to 764,498 non-diabetic pregnancies. Maternal overweight/obesity increases the risk of adverse outcome in both women with and without T1DM. Within the T1DM cohort, obesity was associated with increased odds of major malformations adjusted OR: 1.77 (1.18-2.65) and preeclampsia adjusted OR: 1.74 (1.35-2.25). T1DM was a significant effect modifier of the association between BMI and major malformations, preeclampsia, LGA and neonatal overweight. Conclusion: In spite of major improvements in the management of type 1 diabetic pregnancies over the years, the present findings clearly demonstrate that T1DM pregnancies still are associated with significantly increased risk of adverse outcomes. An important observation is the rising incidence of LGA infants, which partly can be attributed to a concomitant increase in maternal BMI. This development is worrying as LGA infants face an excess risk of both perinatal and future complications as compared to normal sized infants. The novel and unexpected finding of a gender difference in fetal macrosomia requires further investigations

    Edge effects in 3D dosimetry: characterisation and correction of the non-uniform dose response of PRESAGEĀ®.

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    Previous work has shown that PRESAGEĀ® can be used successfully to perform 3D dosimetric measurements of complex radiotherapy treatments. However, measurements near the sample edges are known to be difficult to achieve. This is an issue when the doses at air-material interfaces are of interest, for example when investigating the electron return effect (ERE) present in treatments delivered by magnetic resonance (MR)-linac systems. To study this effect, a set of 3.5 cm-diameter cylindrical PRESAGEĀ® samples was uniformly irradiated with multiple dose fractions, using either a conventional linac or an MR-linac. The samples were imaged between fractions using an optical-CT, to read out the corresponding accumulated doses. A calibration between TPS-predicted dose and optical-CT pixel value was determined for individual dosimeters as a function of radial distance from the axis of rotation. This data was used to develop a correction that was applied to four additional samples of PRESAGEĀ® of the same formulation, irradiated with 3D-CRT and IMRT treatment plans, to recover significantly improved 3D measurements of dose. An alternative strategy was also tested, in which the outer surface of the sample was physically removed prior to irradiation. Results show that for the formulation studied here, PRESAGEĀ® samples have a central region that responds uniformly and an edge region of 6-7 mm where there is gradual increase in dosimeter response, rising to an over-response of 24%-36% at the outer boundary. This non-uniform dose response increases in both extent and magnitude over time. Both mitigation strategies investigated were successful. In our four exemplar studies, we show how discrepancies at edges are reduced from 13%-37% of the maximum dose to between 2 and 8%. Quantitative analysis shows that the 3D gamma passing rates rise from 90.4, 69.3, 63.7 and 43.6% to 97.3, 99.9, 96.7 and 98.9% respectively

    Weak and Strong coupling regimes in plasmonic-QED

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    We present a quantum theory for the interaction of a two level emitter with surface plasmon polaritons confined in single-mode waveguide resonators. Based on the Green's function approach, we develop the conditions for the weak and strong coupling regimes by taking into account the sources of dissipation and decoherence: radiative and non-radiative decays, internal loss processes in the emitter, as well as propagation and leakage losses of the plasmons in the resonator. The theory is supported by numerical calculations for several quantum emitters, GaAs and CdSe quantum dots and NV centers together with different types of resonators constructed of hybrid, cylindrical or wedge waveguides. We further study the role of temperature and resonator length. Assuming realistic leakage rates, we find the existence of an optimal length at which strong coupling is possible. Our calculations show that the strong coupling regime in plasmonic resonators is accessible within current technology when working at very low temperatures (<4K). In the weak coupling regime our theory accounts for recent experimental results. By further optimization we find highly enhanced spontaneous emission with Purcell factors over 1000 at room temperature for NV-centers. We finally discuss more applications for quantum nonlinear optics and plasmon-plasmon interactions.Comment: published as Phys. Rev. B 87, 115419 (2013

    Dose verification of dynamic MLC-tracked radiotherapy using small PRESAGE (R) 3D dosimeters and a motion phantom

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    With the increasing complexity of radiotherapy treatments typical 1D and 2D quality assurance (QA) detectors may fail to detect out-of-plane dose discrepancies, in particular in the presence of motion. In this work, small samples of the PRESAGEĀ® 3D radiochromic dosimeter were used in combination with a motion phantom to measure real-time multileaf collimator (MLC)-tracked radiotherapy treatments. A different sample of PRESAGEĀ® was irradiated for each of three different irradiation scenarios: (1) static: static sample, without tracking (2) motion: moving sample, without tracking and (3) tracking: moving sample, with tracking. Our in-house software DynaTrack dynamically moves the linac's MLC leafs based on the target position. The doses delivered to the samples were reconstructed based on the recorded positions of the MLC and phantom during the beam delivery. PRESAGEĀ® samples were imaged with an in-house optical-CT scanner. Comparison between simulated and measured 3D dose showed good agreement for all three irradiation scenarios (static: 99.2%; motion: 99.7%; tracking: 99.3% with a 3%, 2 mm and a 10% threshold local gamma criterion), failing only at the edges of the PRESAGEĀ® samples (~ 6 mm). Given that the dose distributions deposited using the DynaTrack system have been independently verified, this experiment demonstrates the ability of PRESAGE to measure 3D doses correctly in a tracking context. We conclude that this methodology could be used in the future to validate the delivery of dynamic MLC-tracked radiotherapy

    The Vascularization of the Skin of the Atlantic Hagfish, Myxine glutinosa L. as Revealed by Scanning Electron Microscopy of Vascular Corrosion Casts

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    The vascularization of three different (A, B, C) skin regions (from the level of the heart to the cloaca including dorsal, lateral and ventral skin areas) of the Atlantic hagfish, Myxine glutinosa L. was studied by scanning electron microscopy of vascular corrosion casts. Vessel variables were measured either from semithin sections (diameters) or from vascular corrosion casts (diameters, lengths) and total blood capacities as well as vessel surfaces per unit skin area (mm2) were calculated. There are no significant differences in the number of subepidermal capillary meshes (ranging from 164 to 185 meshes per micrograph) in areas A, B or C nor in vessel lengths. The average vessel length per mm2 is 32 mm. Assuming an average diameter of 22.3 Ī¼m these vessels have an average surface of 2.24 mm2 and a volume of 12.5 nanoliters (nl). In contrary weighing two pieces ( 5 mm times 5 mm in size) of the whole skin vascular bed - knowing the density of the casting medium -results in only one fifth of that volume. Overestimation of vessel lengths and diameters by measuring casted structures from micrographs on the one hand and inaccuracies in weighing or dissection of casted skin pieces on the other hand are discussed as sources of observed differences
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