1,538 research outputs found
Improving the Feeding Value of Dryland Lucerne in Australia
Lucerne (Medicago sativa L.) is the most widely grown perennial legume species in southern Australia. Within Australian farming systems it plays an important role in the provision of high-quality feed for livestock, nitrogen fixation and dewatering soils to reduce watertable recharge and dryland salinity (Cocks 2001). The majority of lucerne varieties have been developed for the areas with high rainfall or supplementary irrigation. The new challenge is to develop lucerne cultivars specifically for dryland mixed farming systems in temperate and mediterranean climate zones (Humphries and Auricht, 2001). Persistence in these environments and feeding value to sheep are critical selection traits. In this paper we compare nutritive traits of 35 commercial and experimental accessions of lucerne, sampled during the vegetative phase, and test the hypothesis that there will be significant differences between the accessions for in vitro dry matter digestibility (DMD), crude protein (CP), acid detergent fibre (ADF), neutral detergent fibre (NDF) and hemicellulose
The maintenance of urban circulation: An operational logic of infrastructural control
This paper examines the increased visibility of urban infrastructures occurring through a close coupling of information technologies and the selective integration of urban services. It asks how circulatory flow is managed in the contemporary city, by focusing on the emergence of new forms of governmentality associated with “smart” technologies. Drawing on Foucault’s governmentality, and based on a case study of Rio de Janeiro’s Operations Centre (COR), the paper argues that new understandings of the city are being developed, representing a new mode of urban infrastructure based on the partial and selective rebundling of splintered networks and fragmented urban space. The COR operates through a “un-black boxing” of urban infrastructures, where the extension of control room logics to the totality of the city points to their fragility and the continuous effort involved in their operational accomplishment. It also functions through a collapse in relations of control—of the everyday and the emergency—, which, enabled by the incorporation of the public in operational control, further raise public awareness of urban infrastructures. These characteristics point to a specific form of urban governmentality based on the operationalisation of infrastructural flows and the development of novel ways of seeing and engaging with the city
Manipulating ultracold atoms with a reconfigurable nanomagnetic system of domain walls
The divide between the realms of atomic-scale quantum particles and
lithographically-defined nanostructures is rapidly being bridged. Hybrid
quantum systems comprising ultracold gas-phase atoms and substrate-bound
devices already offer exciting prospects for quantum sensors, quantum
information and quantum control. Ideally, such devices should be scalable,
versatile and support quantum interactions with long coherence times.
Fulfilling these criteria is extremely challenging as it demands a stable and
tractable interface between two disparate regimes. Here we demonstrate an
architecture for atomic control based on domain walls (DWs) in planar magnetic
nanowires that provides a tunable atomic interaction, manifested experimentally
as the reflection of ultracold atoms from a nanowire array. We exploit the
magnetic reconfigurability of the nanowires to quickly and remotely tune the
interaction with high reliability. This proof-of-principle study shows the
practicability of more elaborate atom chips based on magnetic nanowires being
used to perform atom optics on the nanometre scale.Comment: 4 pages, 4 figure
Probing the Evolution of IR Properties of z~6 Quasars: Spitzer Observations
We present Spitzer observations of thirteen z~6 quasars using the Infrared
Array Camera (IRAC) and Multiband Imaging Photometer for Spitzer (MIPS). All
the quasars except SDSS J000552.34-000655.8 (SDSS J0005-0006) were detected
with high S/N in the four IRAC channels and the MIPS 24um band, while SDSS
J0005-0006 was marginally detected in the IRAC 8.0um band, and not detected in
the MIPS 24um band. We find that most of these quasars have prominent emission
from hot dust as evidenced by the observed 24um fluxes. Their spectral energy
distributions (SEDs) are similar to those of low-redshift quasars at rest-frame
0.15-3.5 um, suggesting that accretion disks and hot-dust structures for these
sources already have reached maturity. However, SDSS J0005-0006 has an unusual
SED that lies significantly below low-redshift SED templates at rest-frame 1
and 3.5 um, and thus shows a strong near-IR (NIR) deficit and no hot-dust
emission. Type I quasars with extremely small NIR-to-optical flux ratios like
SDSS J0005-0006 are not found in low-redshift quasar samples, indicating that
SDSS J0005-0006 has different dust properties at high redshift. We combine the
Spitzer observations with X-ray, UV/optical, mm/submm and radio observations to
determine bolometric luminosities for all the quasars. We find that the four
quasars with central black-hole mass measurements have Eddington ratios of
order unity.Comment: 22 pages, 5 figures, accepted by A
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