The feeding value of the ration based on alfalfa haylage supplemented with high moisture corn in wether sheep

The objectives of the experiment were to examine the effects of high moisture corn (HMC) supplementation to alfalfa haylage (Medicago sativa L.) (AH) on feed intake, digestibility and nitrogen (N) balance in wether sheep. The study consisted of three feeding treatments incorporating AH only and AH supplemented with 5 or 10 g HMC d-1kg-1 body weight of Suffolk wethers. Inclusion of HMC in the AH based ration had negative linear effects on acid detergent fibre (ADF) intake (p<0.001) and digestibility (p<0.05) while a positive on the digestibility of dry matter (DM) (p<0.05), organic matter (OM) (p<0.01) and the digestibility of OM in DM (D-value) (p<0.01). A positive associative response of AH and HMC was observed for DM and OM ad libitum intake (g kg-1M0.75d-1) (quadratic, p<0.05 and p<0.01, respectively). Negative linear effects of AH and HMC were observed for nitrogen (N) intake (p<0.05). The inclusion of HMC into AH based ration did not influence N balance in wether sheep. It was concluded that a positive associative response of the two forages was recorded for a limited number of parameters, probably due to lower quality of HMC than required for improved utilization of the AH based ration

HAT-P-13: a multi-site campaign to detect the transit of the second planet in the system

A possible transit of HAT-P-13c has been predicted to occur on 2010 April 28. Here we report on the results of a multi-site campaign that has been organised to detect the event. CCD photometric observations have been carried out at five observatories in five countries. We reached 30% time coverage in a 5 days interval centered on the suspected transit of HAT-P-13c. Two transits of HAT-P-13b were also observed. No transit of HAT-P-13c has been detected while the campaign was on. By a numerical experiment with 10^5 model systems we conclude that HAT-P-13c is not a transiting exoplanet with a significance level from 65% to 72%, depending on the planet parameters and the prior assumptions. We present two times of transit of HAT-P-13b ocurring at BJD 2455141.5522 +- 0.0010 and BJD 2455249.4508 +- 0.0020. The TTV of HAT-P-13b is consistent with zero within 0.001 days. The refined orbital period of HAT-P-13b is 2.916293 +- 0.000010 days.Comment: 5 pages, 4 figures, to be accepted by A&

The Patterns of High-Level Magnetic Activity Occurring on the Surface of V1285 Aql: The OPEA Model of Flares and DFT Models of Stellar Spots

Statistically analyzing Johnson UBVR observations of V1285 Aql during the three observing seasons, both activity level and behavior of the star are discussed in respect to obtained results. We also discuss the out-of-flare variation due to rotational modulation. Eighty-three flares were detected in the U-band observations of season 2006 . First, depending on statistical analyses using the independent samples t-test, the flares were divided into two classes as the fast and the slow flares. According to the results of the test, there is a difference of about 73 s between the flare-equivalent durations of slow and fast flares. The difference should be the difference mentioned in the theoretical models. Second, using the one-phase exponential association function, the distribution of the flare-equivalent durations versus the flare total durations was modeled. Analyzing the model, some parameters such as plateau, half-life values, mean average of the flare-equivalent durations, maximum flare rise, and total duration times are derived. The plateau value, which is an indicator of the saturation level of white-light flares, was derived as 2.421{\pm}0.058 s in this model, while half-life is computed as 201 s. Analyses showed that observed maximum value of flare total duration is 4641 s, while observed maximum flare rise time is 1817 s. According to these results, although computed energies of the flares occurring on the surface of V1285 Aql are generally lower than those of other stars, the length of its flaring loop can be higher than those of more active stars.Comment: 44 pages, 10 figures, 5 tables, 2011PASP..123..659

Quiescent Radio Emission from Southern Late-type M Dwarfs and a Spectacular Radio Flare from the M8 Dwarf DENIS 1048-3956

We report the results of a radio monitoring program conducted at the Australia Telescope Compact Array to search for quiescent and flaring emission from seven nearby Southern late-type M and L dwarfs. Two late-type M dwarfs, the M7 V LHS 3003 and the M8 V DENIS 1048-3956, were detected in quiescent emission at 4.80 GHz. The observed emission is consistent with optically thin gyrosynchrotron emission from mildly relativistic (~1-10 keV) electrons with source densities n_e ~ 10 G magnetic fields. DENIS 1048-3956 was also detected in two spectacular, short-lived flares, one at 4.80 GHz (peak f_nu = 6.0+/-0.8 mJy) and one at 8.64 GHz (peak f_nu = 29.6+/-1.0 mJy) approximately 10 minutes later. The high brightness temperature (T_B >~ 10^13 K), short emission period (~4-5 minutes), high circular polarization (~100%), and apparently narrow spectral bandwidth of these events imply a coherent emission process in a region of high electron density (n_e ~ 10^11-10^12 cm^-3) and magnetic field strength (B ~ 1 kG). If the two flare events are related, the apparent frequency drift in the emission suggests that the emitting source either moved into regions of higher electron or magnetic flux density; or was compressed, e.g., by twisting field lines or gas motions. The quiescent fluxes from the radio-emitting M dwarfs violate the Gudel-Benz empirical radio/X-ray relations, confirming a trend previously noted by Berger et al. (abridged)Comment: 28 pages, 8 figures, accepted for publication in Ap

The HADES RV Programme with HARPS-N@TNG IV. Time resolved analysis of the Ca ii H&K and H{\alpha} chromospheric emission of low-activity early-type M dwarfs

M dwarfs are prime targets for planet search programs, particularly of those focused on the detection and characterization of rocky planets in the habitable zone. Understanding their magnetic activity is important because it affects our ability to detect small planets, and it plays a key role in the characterization of the stellar environment. We analyze observations of the Ca II H&K and H{\alpha} lines as diagnostics of chromospheric activity for low-activity early-type M dwarfs. We analyze the time series of spectra of 71 early-type M dwarfs collected for the HADES project for planet search purposes. The HARPS-N spectra provide simultaneously the H&K doublet and the H{\alpha} line. We develop a reduction scheme able to correct the HARPS-N spectra for instrumental and atmospheric effects, and to provide flux-calibrated spectra in units of flux at the stellar surface. The H&K and H{\alpha} fluxes are compared with each other, and their variability is analyzed. We find that the H and K flux excesses are strongly correlated with each other, while the H{\alpha} flux excess is generally less correlated with the H&K doublet. We also find that H{\alpha} emission does not increase monotonically with the H&K line flux, showing some absorption before being filled in by chromospheric emission when H&K activity increases. Analyzing the time variability of the emission fluxes, we derive a tentative estimate of the rotation period (of the order of a few tens of days) for some of the program stars, and the typical lifetime of chromospheric active regions (a few stellar rotations). Our results are in good agreement with previous studies. In particular, we find evidence that the chromospheres of early-type M dwarfs could be characterized by different filaments coverage, affecting the formation mechanism of the H{\alpha} line. We also show that chromospheric structure is likely related to spectral type

MAIZE SILAGE SUPPLEMENTATION TO GRASS SILAGE INCREASES NITROGEN UTILISATION IN WETHER SHEEP

Cilj istraživanja bio je utvrditi utjecaj dodatka kukuruzne silaže (Zea mays L.) travnoj silaži različitih rokova košnje na iskoristivost dušika u hranidbi kastriranih ovnova. Travna silaža u kojoj je dominirala klupčasta oštrica (Dactylis glomerata L.) (80%) je spremljena u tri fenološke faze razvoja klupčaste oštrice; vlatanje, metličanje, cvatnja. Istraživanje je obuhvatilo 10 hranidbenih tretmana: travna silaža 1. roka košnje (TS1), travna silaža 2. roka košnje (TS2), travna silaža 3. roka košnje (TS3), kukuruzna silaža (KS), te hranidbene tretmane TS1, TS2 i TS3 u interakciji s KS (33, odnosno 67% u suhoj tvari (ST) obroka). Pokus je postavljen kao nepotpuni changeover plan s 10 kastriranih ovnova Charolais pasmine. Sadržaj ST u TS1, TS2 i TS3 je iznosio 396, 408 i 463 g kg-1 svježeg uzorka. S odgađanjem roka košnje travne mase za siliranje opadao je sadržaj sirovih proteina (SP) u TS2 u odnosu na TS1, te u TS3 u odnosu na TS2 (P<0,001), a rastao sadržaj neutralnih detergent vlakana (NDV) (P<0,05) i kiselih detergent vlakana (KDV) (P<0,001). KS je sadržavala 264 g ST kg-1 svježeg uzorka, 61,6 g SP kg-1 ST, te 211 g škroba kg-1 ST. Dodatak KS (33, odnosno 67%) travnim silažama (TS1, TS2 i TS3) je doveo do pozitivnog linearnog utjecaja (P<0,01) i pozitivnog združenog utjecaja (kvadratni, P<0,01) na konzumaciju N, te do pozitivnog združenog utjecaja (kvadratni, P<0,05) na iskoristivost N u hranidbi kastriranih ovnova.The objective of this experiment was to study the effects of maize silage (MS) supplementation (Zea mays L.) to grass silage (GS) harvested at three stages of maturity on nitrogen (N) utilisation in wether sheep. GS dominated by orchardgrass (Dactylis glomerata L.) (80%) was harvested at three maturity stages of orchardgrass: late vegetative (GS1), internode elongation (GS2) and flowering growth stage (GS3). The study consisted of ten feeding treatments incorporating GS1, GS2, GS3 and MS fed alone and forage mixtures of GS1, GS2, GS3 and MS (67 or 33% dry matter (DM) basis). DM concentrations in GS1, GS2 and GS3 were 396, 408 i 463 g kg-1 fresh sample, respectively. Delayed harvesting lowered (P<0.05) the crude protein (CP) concentration in GS2 compared to GS1 and in GS3 compared to GS2, while increased neutral detergent fibre (NDF) (P<0.05) and acid detergent fibre (ADF) concentration (P<0.001). The DM content (g kg-1fresh sample) and starch concentration (g kg-1 DM) of MS were 264 and 211, respectively. Inclusion of MS (33 or 67%) into grass silage based ration (GS1, GS2 and GS3) had positive linear (P<0.01) and positive associative effect (quadratic, P<0.01) on N intake as well as positive associative effect (quadratic, P< 0.05) on N utilisation in wether sheep

Multifrequency Photo-polarimetric WEBT Observation Campaign on the Blazar S5 0716+714: Source Microvariability and Search for Characteristic Timescales

Here we report on the results of the WEBT photo-polarimetric campaign targeting the blazar S5~0716+71, organized in March 2014 to monitor the source simultaneously in BVRI and near IR filters. The campaign resulted in an unprecedented dataset spanning $\sim 110$\,h of nearly continuous, multi-band observations, including two sets of densely sampled polarimetric data mainly in R filter. During the campaign, the source displayed pronounced variability with peak-to-peak variations of about $30\%$ and "bluer-when-brighter" spectral evolution, consisting of a day-timescale modulation with superimposed hourlong microflares characterized by $\sim 0.1$\,mag flux changes. We performed an in-depth search for quasi-periodicities in the source light curve; hints for the presence of oscillations on timescales of $\sim 3$\,h and $\sim 5$\,h do not represent highly significant departures from a pure red-noise power spectrum. We observed that, at a certain configuration of the optical polarization angle relative to the positional angle of the innermost radio jet in the source, changes in the polarization degree led the total flux variability by about 2\,h; meanwhile, when the relative configuration of the polarization and jet angles altered, no such lag could be noted. The microflaring events, when analyzed as separate pulse emission components, were found to be characterized by a very high polarization degree ($> 30\%$) and polarization angles which differed substantially from the polarization angle of the underlying background component, or from the radio jet positional angle. We discuss the results in the general context of blazar emission and energy dissipation models.Comment: 16 pages, 17 Figures; ApJ accepte

Observations and modelling of pulsed radio emission from CU Virginis

We present 13 cm and 20 cm radio observations of the magnetic chemically peculiar star CU Virginis taken with the Australia Telescope Compact Array. We detect two circularly polarised radio pulses every rotation period which confirm previous detections. In the first pulse, the lower frequency emission arrives before the higher frequency emission and the ordering reverses in the second pulse. In order to explain the frequency dependence of the time between the two pulses, we construct a geometric model of the magnetosphere of CU Virginis, and consider various emission angles relative to the magnetic field lines. A simple electron cyclotron maser emission model, in which the emission is perpendicular to the magnetic field lines, is not consistent with our data. A model in which the emission is refracted through cold plasma in the magnetosphere is shown to have the correct pulse arrival time frequency dependence.Comment: Accepted by MNRA