128 research outputs found
Sowing Date Affects Dry Matter Yield of Fodder Beet (\u3ci\u3eBeta vulgaris\u3c/i\u3e L.) Crops and Farm Profitability
Fodder beet (Beta vulgaris L.) is a high yielding and high energy supplementary ruminant feed. Including the crop in a pasture system means loss in production and additional costs during crop establishment, but economic benefits may be recovered with increased seasonal productivity and feed quality. In this study, the Agricultural Production Systems sIMulator was used to estimate herbage production of a typical dairy farm in the Canterbury region of New Zealand based on using a ryegrass (Lolium perenne L.)-clover (Trifolium repens L.) pasture (“Pasture only”) or pasture in combination with fodder beet as winter feed (“Pasture+Fodder beet (FB)”). Mean yields of pasture were used to estimate the potential pasture yield lost from spraying out paddocks 1 month before establishing fodder beet. Fodder beet (‘Rivage’) yields from a 2014 sowing date trial: 19 September (Sep-FB), 17 October (Oct-FB), 17 November (Nov-FB), and 15 December (Dec-FB) were used. Dry matter (DM) yield was determined on 15 June 2015. Yield was 27 t DM/ha for both Sep-FB and Oct-FB and was reduced by 23 and 32% in Nov-FB and Dec-FB, respectively. The total annual yield for “Pasture only” was 16.7 t DM/ha compared with adjusted yield of 29.5, 30.2, 25.7 and 24.9 t DM/ha for “Pasture+Sep-FB”, “Pasture+Oct-FB”, “Pasture+Nov-FB” and “Pasture+Dec-FB”, respectively. Production cost was NZ0.09/kg DM for “Pasture only”. Production costs increased to NZ0.12/kg DM for “Pasture+Dec-FB”, but revenue from sale of surplus feed partially offset these costs. Our results show that sowing in October was the most profitable option. Yield gains from sowing fodder beet in September are unlikely because of low temperatures limiting crop growth. Delaying sowing can increase production costs and yield penalty, but potential returns are greater, compared with “Pasture only”
Options for Improved Biomass Production in Feeding Systems for Dairying in High Rainfall Environments in New Zealand
New Zealand dairy production has expanded into marginal climates and soil types on the premise of excellent profitability and efficient utilisation of forage. Annual pasture production in the cool West Coast of the South Island (rainfall 2042-2933 mm) is15,000 kg. Increased farm production and feeding of high quality biomass, from imported feed or supplementary feed crops grown on- farm, are needed to improve milk solid output. Small plot trials with spring and early summer-sown brassicas, cereals and maize were the focus for development of systems to maximise and manage the seasonal feed supply. The effect of sowing time, fertiliser timing and rate of N and K fertiliser application were studied to quantify the risks of crop failure in the high rainfall and low radiation environment. The aim was to increase forage supply/ha in a predominantly grass-based system and reduce associated risks to environmental sustainability
Irrigation Management Strategies for Fodder Beet (\u3ci\u3eBeta vulgaris\u3c/i\u3e L.) Crops
The production of fodder beet (Beta vulgaris L.) in New Zealand is concentrated in the South Island, and often requires irrigation to achieve high yields. Development of efficient irrigation management strategies requires information on the effect of timing and rate of irrigation on crop growth. A field study was conducted on a moderately deep soil at Chertsey, Canterbury, New Zealand, to evaluate crop growth responses to five irrigation managements: Rain-fed (control), weekly replacement of full evapotranspiration (FullET-weekly), and 50% of evapotranspiration replaced weekly (HalfET-weekly), fortnightly (HalfET-2weekly) or 3-weekly (HalfET-3weekly). Irrigation to replace ET was adjusted to account for rainfall received between irrigation events. The crop was sown on 11 October 2015. Dry matter (DM) and green leaf area index (LAI) were quantified at 4-weekly intervals from 21 December 2015 until 16 May 2016. Water use efficiency (WUE) was calculated from weekly time domain reflectometry and neutron probe measurements of volumetric soil water content (to 0.8 m depth) and crop biomass. Final yield was lowest for Rain-fed (17.1 t DM/ha) and highest for FullET-weekly (28.9 t DM/ha) treatments. The remaining treatments did not differ in yield, producing 22.4±1.6 t DM/ha, but differed significantly from the Rain-fed and FullET-weekly treatments. Yield differences were associated with the rate of leaf area expansion and duration of critical LAI values (≥ 3.0 m2/m2), which were greater for FullET-weekly than for other treatments. Rain-fed and FullET-weekly treatments resulted in the highest and lowest WUE (81 versus 47 kg DM/ha/mm). The remaining treatments did not differ in WUE, averaging 67±3.6 kg DM/ha/mm. Our results show yield benefits from irrigation, with the best outcome from FullET-weekly given the soil type and weather conditions. However, under water restriction conditions, the HalfET-3weekly management is recommended over more frequent partial ET replacements because it would reduce irrigation costs without penalising yield
23 High Redshift Supernovae from the IfA Deep Survey: Doubling the SN Sample at z>0.7
We present photometric and spectroscopic observations of 23 high redshift
supernovae spanning a range of z=0.34-1.03, 9 of which are unambiguously
classified as Type Ia. These supernovae were discovered during the IfA Deep
Survey, which began in September 2001 and observed a total of 2.5 square
degrees to a depth of approximately m=25-26 in RIZ over 9-17 visits, typically
every 1-3 weeks for nearly 5 months, with additional observations continuing
until April 2002. We give a brief description of the survey motivations,
observational strategy, and reduction process. This sample of 23 high-redshift
supernovae includes 15 at z>0.7, doubling the published number of objects at
these redshifts, and indicates that the evidence for acceleration of the
universe is not due to a systematic effect proportional to redshift. In
combination with the recent compilation of Tonry et al. (2003), we calculate
cosmological parameter density contours which are consistent with the flat
universe indicated by the CMB (Spergel et al. 2003). Adopting the constraint
that Omega_total = 1.0, we obtain best-fit values of (Omega_m,
Omega_Lambda)=(0.33, 0.67) using 22 SNe from this survey augmented by the
literature compilation. We show that using the empty-beam model for
gravitational lensing does not eliminate the need for Omega_Lambda > 0.
Experience from this survey indicates great potential for similar large-scale
surveys while also revealing the limitations of performing surveys for z>1 SNe
from the ground.Comment: 67 pages, 12 figures, 12 tables, accepted for publication in the
Astrophysical Journa
On the fate of the secondary white dwarf in double-degenerate double-detonation Type Ia supernovae
The progenitor systems and explosion mechanism of Type Ia supernovae are
still unknown. Currently favoured progenitors include double-degenerate systems
consisting of two carbon-oxygen white dwarfs with thin helium shells. In the
double-detonation scenario, violent accretion leads to a helium detonation on
the more massive primary white dwarf that turns into a carbon detonation in its
core and explodes it. We investigate the fate of the secondary white dwarf,
focusing on changes of the ejecta and observables of the explosion if the
secondary explodes as well rather than survives. We simulate a binary system of
a and a carbon-oxygen white dwarf with
helium shells each. We follow the system self-consistently from
inspiral to ignition, through the explosion, to synthetic observables. We
confirm that the primary white dwarf explodes self-consistently. The helium
detonation around the secondary white dwarf, however, fails to ignite a carbon
detonation. We restart the simulation igniting the carbon detonation in the
secondary white dwarf by hand and compare the ejecta and observables of both
explosions. We find that the outer ejecta at are
indistinguishable. Light curves and spectra are very similar until d
after explosion and the ejecta are much more spherical than for violent merger
models. The inner ejecta differ significantly which slows down the decline rate
of the bolometric light curve after maximum of the model with a secondary
explosion by about 20 per cent. We expect future synthetic 3D nebular spectra
to confirm or rule out either model.Comment: 12 pages, 7 figures, submitted to MNRAS, comments welcom
Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa
Homo naledi is a previously-unknown species of extinct hominin discovered within the Dinaledi Chamber of the Rising Star cave system, Cradle of Humankind, South Africa. This species is characterized by body mass and stature similar to small-bodied human populations but a small endocranial volume similar to australopiths. Cranial morphology of H. naledi is unique, but most similar to early Homo species including Homo erectus, Homo habilis or Homo rudolfensis. While primitive, the dentition is generally small and simple in occlusal morphology. H. naledi has humanlike manipulatory adaptations of the hand and wrist. It also exhibits a humanlike foot and lower limb. These humanlike aspects are contrasted in the postcrania with a more primitive or australopith-like trunk, shoulder, pelvis and proximal femur. Representing at least 15 individuals with most skeletal elements repeated multiple times, this is the largest assemblage of a single species of hominins yet discovered in Africa
New fossil remains of Homo naledi from the Lesedi Chamber, South Africa
The Rising Star cave system has produced abundant fossil hominin remains within the Dinaledi Chamber, representing a minimum of 15 individuals attributed to Homo naledi. Further exploration led to the discovery of hominin material, now comprising 131 hominin specimens, within a second chamber, the Lesedi Chamber. The Lesedi Chamber is far separated from the Dinaledi Chamber within the Rising Star cave system, and represents a second depositional context for hominin remains. In each of three collection areas within the Lesedi Chamber, diagnostic skeletal material allows a clear attribution to H. naledi. Both adult and immature material is present. The hominin remains represent at least three individuals based upon duplication of elements, but more individuals are likely present based upon the spatial context. The most significant specimen is
the near-complete cranium of a large individual, designated LES1, with an endocranial volume of approximately 610 ml and associated postcranial remains. The Lesedi Chamber skeletal sample extends our knowledge of the morphology and variation of H. naledi, and evidence of H. naledi from both recovery localities shows a consistent pattern of differentiation from other hominin species
Telerobotic Pointing Gestures Shape Human Spatial Cognition
This paper aimed to explore whether human beings can understand gestures
produced by telepresence robots. If it were the case, they can derive meaning
conveyed in telerobotic gestures when processing spatial information. We
conducted two experiments over Skype in the present study. Participants were
presented with a robotic interface that had arms, which were teleoperated by an
experimenter. The robot could point to virtual locations that represented
certain entities. In Experiment 1, the experimenter described spatial locations
of fictitious objects sequentially in two conditions: speech condition (SO,
verbal descriptions clearly indicated the spatial layout) and speech and
gesture condition (SR, verbal descriptions were ambiguous but accompanied by
robotic pointing gestures). Participants were then asked to recall the objects'
spatial locations. We found that the number of spatial locations recalled in
the SR condition was on par with that in the SO condition, suggesting that
telerobotic pointing gestures compensated ambiguous speech during the process
of spatial information. In Experiment 2, the experimenter described spatial
locations non-sequentially in the SR and SO conditions. Surprisingly, the
number of spatial locations recalled in the SR condition was even higher than
that in the SO condition, suggesting that telerobotic pointing gestures were
more powerful than speech in conveying spatial information when information was
presented in an unpredictable order. The findings provide evidence that human
beings are able to comprehend telerobotic gestures, and importantly, integrate
these gestures with co-occurring speech. This work promotes engaging remote
collaboration among humans through a robot intermediary.Comment: 27 pages, 7 figure
Management of intra-abdominal infections : recommendations by the WSES 2016 consensus conference
This paper reports on the consensus conference on the management of intra-abdominal infections (IAIs) which was held on July 23, 2016, in Dublin, Ireland, as a part of the annual World Society of Emergency Surgery (WSES) meeting. This document covers all aspects of the management of IAIs. The Grading of Recommendations Assessment, Development and Evaluation recommendation is used, and this document represents the executive summary of the consensus conference findings.Peer reviewe
- …