1,183 research outputs found
Information processing on smartphones in public versus private
People increasingly turn to news on mobile devices, often while out and about, attending to daily tasks. Yet, we know little about whether attention to and learning from information on a mobile differs by the setting of use. This study builds on Multiple Resource Theory (Wickens, 1984) and the Resource Competition Framework (Oulasvirta et al., 2005) to compare visual attention to a dynamic newsfeed, varying only the setting: private or public. We use mobile eye-tracking to evaluate the effects of setting on attention and assess correspondent learning differences after exposure to the feed, which allows us to uncover a relationship between attention and learning. Findings indicate higher visual attention to mobile newsfeed posts in public, relative to a private setting. Moreover, scrolling through news on a smartphone in public attenuates some knowledge gain but is beneficial for other learning outcomes
Hay-Crop Silages
This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu
Large Magnetic Susceptibility Anisotropy of Metallic Carbon Nanotubes
Through magnetic linear dichroism spectroscopy, the magnetic susceptibility
anisotropy of metallic single-walled carbon nanotubes has been extracted and
found to be 2-4 times greater than values for semiconducting single-walled
carbon nanotubes. This large anisotropy is consistent with our calculations and
can be understood in terms of large orbital paramagnetism of electrons in
metallic nanotubes arising from the Aharonov-Bohm-phase-induced gap opening in
a parallel field. We also compare our values with previous work for
semiconducting nanotubes, which confirm a break from the prediction that the
magnetic susceptibility anisotropy increases linearly with the diameter.Comment: 4 pages, 4 figure
Sap Flow Responses to Warming and Fruit Load in Young Olive Trees
Global warming will likely lead to temperature increases in many regions of South America where temperatures are already considered to be high for olive production. Thus, experimental studies are needed to assess how water use in olive trees may be affected by global warming. The objectives of this study were to (i) evaluate the response of olive tree sap flow, stomatal conductance, and xylem anatomy to elevated temperature and (ii) determine whether fruit load may affect the temperature responses. A warming experiment using well-irrigated olive trees (cv. Arbequina) in open-top chambers (OTCs) with two temperature levels was performed from fruit set to the end of fruit growth in two seasons. Temperature levels were a near ambient control (T0) and a treatment 4°C above the control (T+). Trees were in the chambers for either one (2015–2016) or two seasons (2014–2015, 2015–2016) and were evaluated only in the second season when all trees were 3 years old. Whole-tree sap flow on leaf area basis, stomatal conductance, and aspects of xylem anatomy were measured. Sap flow was slightly higher in T+ than T0 trees heated for one season early in fruit development (summer) likely due to the elevated temperature and increase in vapor pressure deficit. Later in fruit development (fall), sap flow was substantially higher in the T+ trees heated for one season. Total vessel number per shoot was greater in the T+ than the T0 trees at this time due to more small-diameter vessels in the T+ trees, but this did not appear to explain the greater sap flow. The T+ trees that were heated for two seasons had less fruit load than the T0 trees due to little flowering. In contrast to trees heated for one season, sap flow was less in T+ than controls late in fruit development the second season, which was likely related to lower fruit load. An independent experiment using untreated trees confirmed that sap flow decreases when fruit load is below a threshold value. The results emphasize that multiple, interacting factors should be considered when predicting warming effects on water use in olive orchards.Fil: Miserere, Andrea. Universidad Nacional de La Rioja; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro Regional de Investigaciones CientÃficas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones CientÃficas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones CientÃficas y Transferencia Tecnológica de La Rioja. - SecretarÃa de Industria y MinerÃa. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones CientÃficas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones CientÃficas y Transferencia Tecnológica de La Rioja; ArgentinaFil: Searles, Peter Stoughton. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro Regional de Investigaciones CientÃficas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones CientÃficas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones CientÃficas y Transferencia Tecnológica de La Rioja. - SecretarÃa de Industria y MinerÃa. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones CientÃficas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones CientÃficas y Transferencia Tecnológica de La Rioja; ArgentinaFil: Manchó, Guadalupe. Universidad de Buenos Aires. Facultad de AgronomÃa; ArgentinaFil: Maseda, Pablo H.. Universidad de Buenos Aires. Facultad de AgronomÃa; ArgentinaFil: Rousseaux, Maria Cecilia. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro Regional de Investigaciones CientÃficas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones CientÃficas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones CientÃficas y Transferencia Tecnológica de La Rioja. - SecretarÃa de Industria y MinerÃa. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones CientÃficas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones CientÃficas y Transferencia Tecnológica de La Rioja; Argentin
On the Fluctuation Relation for Nose-Hoover Boundary Thermostated Systems
We discuss the transient and steady state fluctuation relation for a
mechanical system in contact with two deterministic thermostats at different
temperatures. The system is a modified Lorentz gas in which the fixed
scatterers exchange energy with the gas of particles, and the thermostats are
modelled by two Nos\'e-Hoover thermostats applied at the boundaries of the
system. The transient fluctuation relation, which holds only for a precise
choice of the initial ensemble, is verified at all times, as expected. Times
longer than the mesoscopic scale, needed for local equilibrium to be settled,
are required if a different initial ensemble is considered. This shows how the
transient fluctuation relation asymptotically leads to the steady state
relation when, as explicitly checked in our systems, the condition found in
[D.J. Searles, {\em et al.}, J. Stat. Phys. 128, 1337 (2007)], for the validity
of the steady state fluctuation relation, is verified. For the steady state
fluctuations of the phase space contraction rate \zL and of the dissipation
function \zW, a similar relaxation regime at shorter averaging times is
found. The quantity \zW satisfies with good accuracy the fluctuation relation
for times larger than the mesoscopic time scale; the quantity \zL appears to
begin a monotonic convergence after such times. This is consistent with the
fact that \zW and \zL differ by a total time derivative, and that the tails
of the probability distribution function of \zL are Gaussian.Comment: Major revision. Fig.10 was added. Version to appear in Journal of
Statistical Physic
Comparison of work fluctuation relations
We compare two predictions regarding the microscopic fluctuations of a system
that is driven away from equilibrium: one due to Crooks [J. Stat. Phys. 90,
1481 (1998)] which has gained recent attention in the context of nonequilibrium
work and fluctuation theorems, and an earlier, analogous result obtained by
Bochkov and Kuzovlev [Zh. Eksp. Teor. Fiz. 72(1), 238247 (1977)]. Both results
quantify irreversible behavior by comparing probabilities of observing
particular microscopic trajectories during thermodynamic processes related by
time-reversal, and both are expressed in terms of the work performed when
driving the system away from equilibrium. By deriving these two predictions
within a single, Hamiltonian framework, we clarify the precise relationship
between them, and discuss how the different definitions of work used by the two
sets of authors gives rise to different physical interpretations. We then
obtain a extended fluctuation relation that contains both the Crooks and the
Bochkov-Kuzovlev results as special cases.Comment: 14 pages with 1 figure, accepted for publication in the Journal of
Statistical Mechanic
Culling Pays
This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu
Deep-water macroalgae from the Canary Islands: new records and biogeographical relationships
Due to the geographical location and paleobiogeography of the Canary Islands, the
seaweed flora contains macroalgae with different distributional patterns. In this contribution, the biogeographical relations of several new records of deep-water macroalgae recently collected around the Canarian archipelago are discussed. These are Bryopsidella neglecta (Berthotd) Rietema,Discosporangium mesarthrocarpum (Meneghini) Hauck, Hincksia onslowensis (Amsler et Kapraun)P.C. Silva, Syringoderma floridana Henry, Peyssonnelia harveyana J. Agardh, Cryptonemia seminervis(C. Agardh) J. Agardh, Botryodadia wynnei Ballantine, Gloiocladia blomquistii (Searles) R. E.Norris, PIahchrysis peltata (W. R. Taylor) P. Huv4 et H. Huv4, Leptofauchea brasiliensis Joly, and Sarcodiotheca divaricata W. R. Taylor. These new records, especially those in the Florideophyceae,support the strong affinity of the Canary Islands seaweed flora with the warm-temperate Mediterranean-Atlantic region. Some species are recorded for the first time from the east coast of the Atlantic Ocean, enhancing the biogeographic relations of the Canarian marine flora with that of the western Atlantic regions
A critical evaluation of the microstructural gradient along the build direction in electron beam melted Ti-6Al-4V alloy
It is generally recognised that electron beam melted (EBM) Ti-6Al-4V alloys exhibit a microstructural gradient along the build direction, but there have been some inconsistent experimental observations and debate as to the origin and magnitude of this effect. Here we present an unambiguous evaluation of this microstructural gradient and associated mechanical property along the EBM build direction on purpose-built round bar RB samples with build height of 380 mm and rectangular plate RP samples with build height of 120 mm. Columnar prior β grain width was found to increase (from 86 ± 38 to 154 ± 56 µm in RB and from 79 ± 34 to 122 ± 56 µm in RP samples) with the build height and the similar increase was also observed for α lath width (from 0.58 ± 24 to 0.87 ± 33 µm in RB and from 1.50 ± 45 to 1.80 ± 49 µm in RP samples). These observations can be attributed to the thermal gradient in the powder bed that produced a cooling rate gradient along the build height. The measured α lath width variation along the build height followed a log-normal distribution. The graded microstructure resulted in a decrease in micro-hardness which correlated very well with the mean α lath width by following a Hall-Petch relation
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