545 research outputs found

    Polarized Diffuse Emission at 2.3 GHz in a High Galactic Latitude Area

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    Polarized diffuse emission observations at 2.3 GHz in a high Galactic latitude area are presented. The 2\degr X 2\degr field, centred in (\alpha=5^h,\delta=-49\degr), is located in the region observed by the BOOMERanG experiment. Our observations has been carried out with the Parkes Radio telescope and represent the highest frequency detection done to date in low emission areas. Because of a weaker Faraday rotation action, the high frequency allows an estimate of the Galactic synchrotron contamination of the Cosmic Microwave Background Polarization (CMBP) that is more reliable than that done at 1.4 GHz. We find that the angular power spectra of the E- and B-modes have slopes of \beta_E = -1.46 +/- 0.14 and \beta_B = -1.87 +/- 0.22, indicating a flattening with respect to 1.4 GHz. Extrapolated up to 32 GHz, the E-mode spectrum is about 3 orders of magnitude lower than that of the CMBP, allowing a clean detection even at this frequency. The best improvement concerns the B-mode, for which our single-dish observations provide the first estimate of the contamination on angular scales close to the CMBP peak (about 2 degrees). We find that the CMBP B-mode should be stronger than synchrotron contamination at 90 GHz for models with T/S > 0.01. This low level could move down to 60-70 GHz the optimal window for CMBP measures.Comment: 5 pages, 6 figures, accepted for publication in MNRAS Letter

    Redefining the requirement for total sulfur amino acids in the diet of barramundi (Lates calcarifer) including assessment of the cystine replacement value

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    This study was designed to confirm a previous estimate of the methionine (Met) and total sulfur amino acid (TSAA) requirement of juvenile barramundi (Lates calcarifer) (Coloso et al., 1999) with a view for further study. Triplicate groups of fish (initial weight: 18.3 g ± 1.5 g) were fed diets with graded levels of dietary Met (7.2–12.8 g kg−1 DM), centred around a previously reported requirement, and a constant dietary cystine (Cys) inclusion (5.9 g kg−1 DM) over a 42 day period. At the termination of the experiment, a significant linear increase (p<0.001) in %BW gain was observed in response to increasing dietary methionine, with no plateau in growth, suggesting the previous estimate of requirement may have been inadequate. A second experiment was designed to re-evaluate the Met/TSAA requirement in which a broader range of methionine inclusion levels were assessed (8.6–21.4 g kg−1 diet DM Met). Triplicate groups of fish (initial weight: 36.4 g ± 8.3 g) were fed the diets for a period of 49 days. A plateau and subsequent depression in growth, as well as significant (p<0.05) effects of dietary Met inclusion on %BW gain, feed conversion ratio (FCR) and protein retention efficiency (PRE) were observed at the conclusion of this experiment. The best fitting of nine nutrient response models, the Compartmental Model (R2=0.71), predicted a requirement for Met of between 10.5 (95% of maximum response) and 13.6 g kg−1 (99% of maximum response) in a diet with 592 g kg−1 CP and 6.6 g kg−1 Cys (17.1–20.2 g kg−1 TSAA; 1.8–2.3% CP Met +1.1% CP Cys). This TSAA requirement is equivalent to 43–51% of the lysine content of the diets. The applicability of this mode of expression and its relation to the ideal protein concept is discussed as is the application of different response models to the data. The impact of dietary Met:Cys ratio was also investigated with results suggesting at least 40% of dietary Met can be replaced with Cys without significantly affecting animal performance. It was concluded that disparity in the estimates of Met and TSAA requirement between this study and that of Coloso et al. (1999) was likely the result of a combination of model choice, experimental design and mode of expression of the requirements

    Sardinia radio telescope finite element model updating by means of photogrammetric measurements

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    The 64 m diameter Sardinia Radio Telescope (SRT), located near Cagliari (Italy), is the world’s second largest fully steerable radio telescope with an active surface. Among its peculiarities is the capability of modifying the configuration of the primary mirror surface by means of electromechanical actuators. This capability enables, within a fixed range, balancing of the deformation caused by external loads. In this way, the difference between the ideal shape of the mirror (which maximizes its performance) and the actual surface can be reduced. The control loop of the radio telescope needs a procedure that is able to predict SRT deformation, with the required accuracy, in order to reduce deviation from the ideal shape. To achieve this aim, a finite element model that can accurately predict the displacements of the structure is required. Unfortunately, the finite element model of the SRT, although very refined, does not give completely satisfactory results, since it does not take into account essential pieces of information, for instance, thermal strains and assembly defects. This paper explores a possible update of the finite element model using only the benchmark data available, i.e. the photogrammetric survey developed during the setup of the reflecting surface. This updating leads to a significant reduction in the differences between photogrammetric data and results of the numerical model. The effectiveness of this tuning procedure is then assessed

    Strategies to increase growth of weaned Bali calves

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    Demand for beef in Indonesia is increasing by 4% per annum, which is unable to be met from domestic supply alone under prevailing cattle management systems. Small-holder farmers within the crop-livestock system of eastern Indonesia have the opportunity to capitalise on this increased demand for beef. An Integrated Village Management System (IVMS) established in Nusa Tenggara Barat successfully increased reproductive output by introducing natural mating, early weaning and more appropriate allocation of available feed resources to match nutrient demands of cattle. It is anticipated that wide scale implementation of the IVMS will result in a large population of early weaned calves across eastern Indonesia and that if these calves are retained by small-holder farmers, and growth rates improved, significant increases in cash flow will ensue. The objective of this project was to evaluate a range of feeding strategies to increase growth rates of 6 month old weaned Bali calves at four sites across eastern Indonesia

    Postprandial plasma free amino acid profile and hepatic gene expression in juvenile barramundi (Lates calcarifer) is more responsive to feed consumption than to dietary methionine inclusion

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    The effects of dietary methionine (Met) supply on the postprandial pattern of plasma free amino acids and the differential expression of several genes associated with a number of sulfur amino acid and protein turnover pathways in the liver of juvenile barramundi (Lates calcarifer) was investigated. At the conclusion of a 49-day growth trial assessing the requirement for dietary Met, three treatments were selected (with deficient (DEF; 8.6 g kg−1), adequate (ADQ; 14.9 g kg−1) and excessive (EXC; 21.4 g kg−1)) levels of dietary Met, based on their respective growth responses. A peak occurred in plasma free Met at 2 h post-feeding in fish fed the DEF and ADQ diets and at 4 h post-feeding in fish in the EXC treatment. Liver samples collected at these timepoints, as well as those taken as a pre-feeding control, were analyzed for expression of genes involved in Met turnover (CGL, MAT-1, MAT-2a) and taurine biosynthetic pathways (CSAD, ADO, CDO), target of rapamycin inhibition (Redd-1), the somatotropic axis (GHR-II, IGFI, IGF-II) and protein turnover pathways (MUL-1, ZFAND-5). Markers of sulfur amino acid turnover were more significantly affected by time after feeding than by dietary Met level, suggesting production of these enzymes may be primarily regulated by the consumption of feed or protein, rather than by the dietary composition. Further, metabolised Met appeared likely to have been directed through S-Adenosylmethionine (SAM) dependent pathways, rather than converted to Cys, which may have contributed to the observed growth response. Both genes influencing the conversion of Met to SAM appear to be active at this lifestage in barramundi. Previously described markers of proteolytic pathways appear to be conserved in this species and we have confirmed that ZFAND-5 is a reliable biomarker of this process in barramundi. A number of important genes were investigated for the first time in this species and shown to be nutritionally regulated

    S-band Polarization All Sky Survey (S-PASS): survey description and maps

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    We present the S-Band Polarization All Sky Survey (S-PASS), a survey of polarized radio emission over the southern sky at Dec~<−1∘< -1^\circ taken with the Parkes radio telescope at 2.3~GHz. The main aim was to observe at a frequency high enough to avoid strong depolarization at intermediate Galactic latitudes (still present at 1.4 GHz) to study Galactic magnetism, but low enough to retain ample Signal-to-Noise ratio (S/N) at high latitudes for extragalactic and cosmological science. We developed a new scanning strategy based on long azimuth scans, and a corresponding map-making procedure to make recovery of the overall mean signal of Stokes QQ and UU possible, a long-standing problem with polarization observations. We describe the scanning strategy, map-making procedure, and validation tests. The overall mean signal is recovered with a precision better than 0.5\%. The maps have a mean sensitivity of 0.81 mK on beam--size scales and show clear polarized signals, typically to within a few degrees of the Galactic plane, with ample S/N everywhere (the typical signal in low emission regions is 13 mK, and 98.6\% of the pixels have S/N >3> 3). The largest depolarization areas are in the inner Galaxy, associated with the Sagittarius Arm. We have also computed a Rotation Measure map combining S-PASS with archival data from the WMAP and Planck experiments. A Stokes II map has been generated, with a sensitivity limited to the confusion level of 9 mK.Comment: Accepted for publication on MNRAS. Maps are available for download at the website indicated in the manuscrip

    Weaning and supplementation increase liveweight gain of Bali (Bos javanicus) cattle of small-holder farmers in Central Lombok, Indonesia

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    One of the constraints for improving productivity of Bali cattle in west Nusa Tenggara Province is the low growth rate of weaned calves. Results of on-station experiments showed that Sesbania grandiflora (sesbania) supplementation can significantly increase live weight gain of weaned calves. The objective of this experiment was to investigate whether sesbania supplementation can increase live weight gain of weaned calves and improve farmer income. This experiment was carried out in Tandek, Labulia Village (treatment village) and in Kelebuh and Sukaraja villages (control villages) central Lombok District from April to October 2008. A total of 21 calves (9 males and 12 females) aged 237±7 days with initial live weight of 122.3±4.5 kg were monitored in Kelebuh and Sukaraja villages (control villages). During the same period, 25 calves (13 males and 12 females) aged 237±6 days with initial weight of 108.8±4.1 kg were monitored in Tandek Village (treatment village) and fed fresh sesbania at 1% dry matter of live weight. To ensure that sesbania was fed at the recommended level, regular weighing of sesbania offered by each farmer was conducted 2-3 times per week. All calves were weighed every month to determine live weight gain. Farmers from the control villages and other villages were invited to a field day conducted in the treatment village at the end of the experiment. The results showed that sesbania supplementation significantly increased live weight gain (0.36±0.01 kg/day for calves in the treatment village compared to 0.22±0.01 kg/day for those in the control villages), increased body condition and health of the calves and improved farmer income. Weaning management and supplementation with sesbania was very easy to implement so most of the farmers participated in this study stated that they were willing to continue this feeding management
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