67 research outputs found
Neutral H density at the termination shock: a consolidation of recent results
We discuss a consolidation of determinations of the density of neutral
interstellar H at the nose of the termination shock carried out with the use of
various data sets, techniques, and modeling approaches. In particular, we focus
on the determination of this density based on observations of H pickup ions on
Ulysses during its aphelion passage through the ecliptic plane. We discuss in
greater detail a novel method of determination of the density from these
measurements and review the results from its application to actual data. The H
density at TS derived from this analysis is equal to 0.087 \pm 0.022 cm-3, and
when all relevant determinations are taken into account, the consolidated
density is obtained at 0.09 \pm 0.022 cm-3. The density of H in CHISM based on
literature values of filtration factor is then calculated at 0.16 \pm 0.04
cm-3.Comment: Submitted to Space Science Review
Spin dynamics in semiconductors
This article reviews the current status of spin dynamics in semiconductors
which has achieved a lot of progress in the past years due to the fast growing
field of semiconductor spintronics. The primary focus is the theoretical and
experimental developments of spin relaxation and dephasing in both spin
precession in time domain and spin diffusion and transport in spacial domain. A
fully microscopic many-body investigation on spin dynamics based on the kinetic
spin Bloch equation approach is reviewed comprehensively.Comment: a review article with 193 pages and 1103 references. To be published
in Physics Reports
Solar parameters for modeling interplanetary background
The goal of the Fully Online Datacenter of Ultraviolet Emissions (FONDUE)
Working Team of the International Space Science Institute in Bern, Switzerland,
was to establish a common calibration of various UV and EUV heliospheric
observations, both spectroscopic and photometric. Realization of this goal
required an up-to-date model of spatial distribution of neutral interstellar
hydrogen in the heliosphere, and to that end, a credible model of the radiation
pressure and ionization processes was needed. This chapter describes the solar
factors shaping the distribution of neutral interstellar H in the heliosphere.
Presented are the solar Lyman-alpha flux and the solar Lyman-alpha resonant
radiation pressure force acting on neutral H atoms in the heliosphere, solar
EUV radiation and the photoionization of heliospheric hydrogen, and their
evolution in time and the still hypothetical variation with heliolatitude.
Further, solar wind and its evolution with solar activity is presented in the
context of the charge exchange ionization of heliospheric hydrogen, and in the
context of dynamic pressure variations. Also the electron ionization and its
variation with time, heliolatitude, and solar distance is presented. After a
review of all of those topics, we present an interim model of solar wind and
the other solar factors based on up-to-date in situ and remote sensing
observations of solar wind. Results of this effort will further be utilised to
improve on the model of solar wind evolution, which will be an invaluable asset
in all heliospheric measurements, including, among others, the observations of
Energetic Neutral Atoms by the Interstellar Boundary Explorer (IBEX).Comment: Chapter 2 in the planned "Cross-Calibration of Past and Present Far
UV Spectra of Solar System Objects and the Heliosphere", ISSI Scientific
Report No 12, ed. R.M. Bonnet, E. Quemerais, M. Snow, Springe
Auroral Processes at the Giant Planets: Energy Deposition, Emission Mechanisms, Morphology and Spectra
The effect of early-weaning rations upon the efficiency of growth and carcass production with some observations on the development of forestomachs in calves
The live-weight gain, efficiency of food conversion, energy and nitrogen accretion as edible carcass, and the forestomach development were measured in three groups of calves fed for 10 weeks (days 19-89 of life) either a diet of 4-5 1 of milk daily, or a concentrate meal containing 4% sodium propionate ad libitum, or a concentrate meal ad libitum. All groups had access to lucerne chaff and water ad libitum. The mean live-weight gains of the three groups of calves were 47-5, 36'6 and 37-1 kg respectively even though their total energy and nitrogen intakes were not significantly different. The provision of dietary propionate did not improve the efficiency of food conversion or of energy or nitrogen accretion as the calves ate less of the meal containing propionate and more lucerne chaff. The differences in live-weight gain could be accounted for by the differences in carcass weight. Associated with the higher live-weight gain was a much higher efficiency of food utilization and of edible carcass energy and nitrogen accretion. The superior efficiency of the unweaned calves was concluded to be due to the liquid portion of the diet by-passing the rumeno-reticulum into the abomasum where the efficiency of utilization of highly digestible protein and carbohydrate is greater. The concentrate plus propionate fed calves ate less concentrate but more chaff and had a lower efficiency of food utilization and edible carcass energy accretion than the other weaned group of calves. The weight of rumeno-reticular tissues was greater in the weaned than in the unwearied calves, although the meal plus propionate group ate similar quantities of chaff to the unweaned group. In all groups, the degree of papillary development was related to the intake of concentrates plus roughage. The most appropriate manner to describe ruminal tissue weight is discussed
Experimentally induced intramammary infection with multiple strains of Streptococcus uberis
The effect of infusing a mixture of 5 Streptococcus uberis strains into mammary quarters of 10 lactating cows was investigated. All 5 strains, which included 2 originally isolated from the dairy environment and 3 from clinical cases of mastitis, were capable of establishing an intramammary infection when infused individually. However, when the 5 strains were infused together, a single strain predominated in 7 out of 10 quarters. One strain in particular prevailed in 4 mammary quarters and was also found to inhibit the growth of the other 4 strains with deferred antagonism on esculin blood agar. The genes required for the production of bacteriocins nisin U and uberolysin were identified in this strain, whereas the other 4 strains contained only uberolysin genes. Direct competition may have occurred between strains within the mammary gland but competition was not apparent when cultured together in UHT milk, where no strain predominated. Although the mechanism is unknown, these results imply that a selection process can occur within the mammary gland, leading to a single strain that is detected upon diagnosis of mastitis
âWind theftâ from onshore wind turbine arrays: Sensitivity to wind farm parameterization and resolution
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