Konsentrasi Asam Lemak Tidak Teresterifikasi (Nonesterified Fatty Acid, NEFA), Albumin, Kalsium Dan Fosfor Dalam Plasma Sebagai Indikator Status Nutrisi Sapi Perah Laktasi

Tujuan penelitian ini adalah untuk mengetahui status gizi sapi perah laktasi didasarkan pada konsentrasi NEFA (nonesterified Asam Lemak), albumin, kalsium, dan fosfor dalam plasma. Tiga puluh dua sapi perah kepala di periode menyusui kedua digunakan untuk up mengambil plasma darah. Uji t dan regresi sama digunakan untuk berbagai penentu dari konsentrasi. Hasil pengamatan yang berarti dan berbagai konsentrasi NEFA 0.17 mEq.L-1 dan 0,11-0,22 mEq.L-1, albumin 2.69 g% dan 2,51-2,87 g%. Kemudian, mean dan berbagai konsentrasi kalsium plasma 9.39 mg% dan 8,90-9,88 mg%, 8.60 dan 8,10-9,10 mg% dari konsentrasi fosfor plasma. Regresi sama berat plasma NEFA (Y) tubuh (X1), produksi susu (X2) adalah Y = 0,163 X1 + 0,215 X2 (R2 = 11,2%, P> 0,05). Regresi sama plasma albumin (Y), berat badan (X1), produksi susu (X2) adalah Y = 0,197 X1 + 0,006 X2 (R2 = 12,3%, P> 0,05). Regresi sama plasma kalsium (Y), berat badan (X1), produksi susu (X2) adalah Y = -0,099 X1 + 0,389 X2 (R2 = 11,9%, P> 0,05), plasma fosfor (Y), berat badan (X1 ), produksi susu (X2) adalah Y = 0.72 X1 + 0,394 X2 (R2 = 19,2%, P> 0,05). Oleh karena itu, cadangan energi (konsentrasi NEFA), kalsium dan fosfor dalam plasma yang paling persyaratan untuk peningkatan produksi susu

Performans Ayam Kampung Super Pada Pakan Yang Disubttusi Dedak Padi Fermentasi Dengan Fermentor Berbeda

Penelitian bertujuan untuk mengetahui pengaruh dedak padi fermentasi dengan fermentor berbeda terhadap performans ayam kampung super. Penelitian dilaksanakan di kandang Kelompok Permata Kota Kendari. Penelitian menggunakan Rancangan Acak Lengkap (RAL) yang terdiri dari 4 perlakuan pakan yaitu R0 = ransum kontrol tanpa dedak padi fermentasi (DP), R1 = 10% dedak padi fermentasi cairan rumen (DPFCR), R2 = 10% dedak padi fermentasi ragi tempe (DPFRTe), R3 = 10% dedak padi fermentasi ragi tape (DPFRTa), dengan 4 kali ulangan. Setiap satuan percobaan terdiri dari 5 ekor ayam kampung super. Parameter yang diukur adalah konsumsi pakan, pertambahan bobot badan, konversi pakan, bobot potong, bobot karkas dan persentase karkas. Data dianalisis dengan analysis of variance (ANOVA) sesuai dengan RAL dan bila terdapat perbedaan antar perlakuan akan dilakukan uji lanjut dengan Uji Tukey (Steel and Toriee, 1991). Hasil penelitian menunjukkan bahwa pemberian dedak padi fermentasi dengan fermentor berbeda tidak berpengaruh nyata (P>0,05) terhadap Konsumsi Pakan, PBB, Bobot Potong, Bobot Karkas dan Persentase karkas. Penggunaan dedak padi fermentasi dengan fermentor berbeda berpengaruh nyata (P<0,05) terhadap konversi ransum. Dari hasil penelitian ini, maka dedak padi fermentasi dapat digunakan 10% dalam ransum untuk mensubtitusi pakan basal.Kata kunci : Ayam Kampung Super, Dedak Padi Fermentasi, Konsumsi Pakan, Konversi Pakan

LOFAR early-time search for coherent radio emission from GRB 180706A

© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.The nature of the central engines of gamma-ray bursts (GRBs) and the composition of their relativistic jets are still under debate. If the jets are Poynting flux dominated rather than baryon dominated, a coherent radio flare from magnetic re-connection events might be expected with the prompt gamma-ray emission. There are two competing models for the central engines of GRBs; a black hole or a newly formed milli-second magnetar. If the central engine is a magnetar it is predicted to produce coherent radio emission as persistent or flaring activity. In this paper, we present the deepest limits to date for this emission following LOFAR rapid response observations of GRB 180706A. No emission is detected to a 3$\sigma$ limit of 1.7 mJy beam$^{-1}$ at 144 MHz in a two-hour LOFAR observation starting 4.5 minutes after the gamma-ray trigger. A forced source extraction at the position of GRB 180706A provides a marginally positive (1 sigma) peak flux density of $1.1 \pm 0.9$ mJy. The data were time-sliced into different sets of snapshot durations to search for FRB like emission. No short duration emission was detected at the location of the GRB. We compare these results to theoretical models and discuss the implications of a non-detection.Peer reviewedFinal Accepted Versio

Revived Fossil Plasma Sources in Galaxy Clusters

© 2020 ESO.It is well established that particle acceleration by shocks and turbulence in the intra-cluster medium can produce cluster-scale synchrotron emitting sources. However, the detailed physics of these particle acceleration processes is still not well understood. One of the main open questions is the role of fossil relativistic electrons that have been deposited in the intracluster medium (ICM) by radio galaxies. These synchrotron-emitting electrons are very difficult to study as their radiative lifetime is only tens of Myr at gigahertz frequencies, and they are therefore a relatively unexplored population. Despite the typical steep radio spectrum due to synchrotron losses, these fossil electrons are barely visible even at radio frequencies well below the gigahertz level. However, when a pocket of fossil radio plasma is compressed, it boosts the visibility at sub-gigahertz frequencies, creating what are known as radio phoenices. This compression can be the result of bulk motion and shocks in the ICM due to merger activity. In this paper we demonstrate the discovery potential of low-frequency radio sky surveys to find and study revived fossil plasma sources in galaxy clusters. We used the 150 MHz TIFR GMRT Sky Survey and the 1.4 GHz NVSS sky survey to identify candidate radio phoenices. A subset of three candidates was studied in detail using deep multi-band radio observations (LOFAR and GMRT), X-ray obserations (Chandra or XMM-Newton), and archival optical observations. Two of the three sources are new discoveries. Using these observations, we identified common observational properties (radio morphology, ultra-steep spectrum, X-ray luminosity, dynamical state) that will enable us to identify this class of sources more easily, and will help us to understand the physical origin of these sources.Peer reviewedFinal Accepted Versio

Remnant radio-loud AGN in the Herschel-ATLAS field

Only a small fraction of observed active galactic nuclei (AGN) display large-scale radio emission associated with jets, yet these radio-loud AGN have become increasingly important in models of galaxy evolution. In determining the dynamics and energetics of the radio sources over cosmic time, a key question concerns what happens when their jets switch off. The resulting ‘remnant' radio-loud AGN have been surprisingly evasive in past radio surveys, and therefore statistical information on the population of radio-loud AGN in their dying phase is limited. In this paper, with the recent developments of Low-Frequency Array (LOFAR) and the Very Large Array, we are able to provide a systematically selected sample of remnant radio-loud AGN in the Herschel-ATLAS field. Using a simple core-detection method, we constrain the upper limit on the fraction of remnants in our radio-loud AGN sample to 9 per cent, implying that the extended lobe emission fades rapidly once the core/jets turn off. We also find that our remnant sample has a wide range of spectral indices (−1.5 ⩽ α1400150 ⩽ −0.5), confirming that the lobes of some remnants may possess flat spectra at low frequencies just as active sources do. We suggest that, even with the unprecedented sensitivity of LOFAR, our sample may still only contain the youngest of the remnant population

The XMM-LSS catalogue: X-ray sources and associated optical data. Version I

Following the presentation of the XMM-LSS X-ray source detection package by Pacaud et al., we provide the source lists for the first 5.5 surveyed square degrees. The catalogues pertain to the [0.5-2] and [2-10] keV bands and contain in total 3385 point-like or extended sources above a detection likelihood of 15 in either band. The agreement with deep logN-logS is excellent. The main parameters considered are position, countrate, source extent with associated likelihood values. A set of additional quantities such as astrometric corrections and fluxes are further calculated while errors on the position and countrate are deduced from simulations. We describe the construction of the band-merged catalogue allowing rapid sub-sample selection and easy cross-correlation with external multi-wavelength catalogues. A small optical CFHTLS multi-band subset of objects is associated wich each source along with an X-ray/optical overlay. We make the full X-ray images available in FITS format. The data are available at CDS and, in a more extended form, at the Milan XMM-LSS database.Comment: 13 pages, 7 figures and 11 tables (fig. 1 and 6 are enclosed in reduced resolution), MNRAS Latex, accepted by MNRA

LOFAR tied-array imaging and spectroscopy of solar S bursts

Context. The Sun is an active source of radio emission that is often associated with energetic phenomena ranging from nanoflares to coronal mass ejections (CMEs). At low radio frequencies (&lt;100 MHz), numerous millisecond duration radio bursts have been reported, such as radio spikes or solar S bursts (where S stands for short). To date, these have neither been studied extensively nor imaged because of the instrumental limitations of previous radio telescopes. Aims. Here, LOw Frequency ARray (LOFAR) observations were used to study the spectral and spatial characteristics of a multitude of S bursts, as well as their origin and possible emission mechanisms. Methods. We used 170 simultaneous tied-array beams for spectroscopy and imaging of S bursts. Since S bursts have short timescales and fine frequency structures, high cadence (~50 ms) tied-array images were used instead of standard interferometric imaging, that is currently limited to one image per second. Results. On 9 July 2013, over 3000 S bursts were observed over a time period of ~8 h. S bursts were found to appear as groups of short-lived (&lt;1 s) and narrow-bandwidth (~2.5 MHz) features, the majority drifting at ~3.5 MHz s-1 and a wide range of circular polarisation degrees (2−8 times more polarised than the accompanying Type III bursts). Extrapolation of the photospheric magnetic field using the potential field source surface (PFSS) model suggests that S bursts are associated with a trans-equatorial loop system that connects an active region in the southern hemisphere to a bipolar region of plage in the northern hemisphere. Conclusions. We have identified polarised, short-lived solar radio bursts that have never been imaged before. They are observed at a height and frequency range where plasma emission is the dominant emission mechanism, however, they possess some of the characteristics of electron-cyclotron maser emission

LOFAR Sparse Image Reconstruction

Context. The LOw Frequency ARray (LOFAR) radio telescope is a giant digital phased array interferometer with multiple antennas distributed in Europe. It provides discrete sets of Fourier components of the sky brightness. Recovering the original brightness distribution with aperture synthesis forms an inverse problem that can be solved by various deconvolution and minimization methods Aims. Recent papers have established a clear link between the discrete nature of radio interferometry measurement and the "compressed sensing" (CS) theory, which supports sparse reconstruction methods to form an image from the measured visibilities. Empowered by proximal theory, CS offers a sound framework for efficient global minimization and sparse data representation using fast algorithms. Combined with instrumental direction-dependent effects (DDE) in the scope of a real instrument, we developed and validated a new method based on this framework Methods. We implemented a sparse reconstruction method in the standard LOFAR imaging tool and compared the photometric and resolution performance of this new imager with that of CLEAN-based methods (CLEAN and MS-CLEAN) with simulated and real LOFAR data Results. We show that i) sparse reconstruction performs as well as CLEAN in recovering the flux of point sources; ii) performs much better on extended objects (the root mean square error is reduced by a factor of up to 10); and iii) provides a solution with an effective angular resolution 2-3 times better than the CLEAN images. Conclusions. Sparse recovery gives a correct photometry on high dynamic and wide-field images and improved realistic structures of extended sources (of simulated and real LOFAR datasets). This sparse reconstruction method is compatible with modern interferometric imagers that handle DDE corrections (A- and W-projections) required for current and future instruments such as LOFAR and SKAComment: Published in A&A, 19 pages, 9 figure

The contribution of discrete sources to the sky temperature at 144 MHz

This paper is part of the 1st data release of the LoTSS Deep Fields. © 2020 The European Southern Observatory (ESO)In recent years, the level of the extragalactic radio background has become a point of considerable interest, with some lines of argument pointing to an entirely new cosmological synchrotron background. The contribution of the known discrete source population to the sky temperature is key to this discussion. Because of the steep spectral index of the excess over the cosmic microwave background, it is best studied at low frequencies where the signal is strongest. The Low-Frequency Array (LOFAR) wide and deep sky surveys give us the best constraints yet on the contribution of discrete extragalactic sources at 144 MHz, and in particular allow us to include contributions from diffuse, low-surface-brightness emission that could not be fully accounted for in previous work. We show that, even with these new data, known sources can still only account for around a quarter of the estimated extragalactic sky temperature at LOFAR frequencies.Peer reviewedFinal Accepted Versio