19,510 research outputs found
A proposed adjustable RF cable connector
In system that requires negligible loss, it may be necessary to adjust cable length to exact multiple of transmitted wavelength. Adjustable cable connector saves time and cost by eliminating need to add to or cut from cable. Device was especially designed for use with high frequencies. For particular application, connector of suitable dimensions should be used
Investigating the Rotational Phase of Stellar Flares on M dwarfs Using K2 Short Cadence Data
We present an analysis of K2 short cadence data of 34 M dwarfs which have
spectral types in the range M0 - L1. Of these stars, 31 showed flares with a
duration between 10-90 min. Using distances obtained from Gaia DR2
parallaxes, we determined the energy of the flares to be in the range
erg. In agreement with previous studies
we find rapidly rotating stars tend to show more flares, with evidence for a
decline in activity in stars with rotation periods longer than 10 days.
The rotational modulation seen in M dwarf stars is widely considered to result
from a starspot which rotates in and out of view. Flux minimum is therefore the
rotation phase where we view the main starspot close to the stellar disk
center. Surprisingly, having determined the rotational phase of each flare in
our study we find none show any preference for rotational phase. We outline
three scenarios which could account for this unexpected finding. The
relationship between rotation phase and flare rate will be explored further
using data from wide surveys such as NGTS and TESS.Comment: Accepted main Journal MNRA
Potential economic gains from using forage legumes in organic livestock systems in northern Europe
This report was presented at the UK Organic Research 2002 Conference of the Colloquium of Organic Researchers (COR).
Forage legumes, with their ability to fix nitrogen biologically, seem especially attractive for organic livestock production. In an attempt to assess their true potential, this study draws on a four-year trial conducted at 12 sites in northern Europe with four different forage legumes. One third of the sites were managed as organic systems, with the harvested forage being fed as silage to dairy cows. Based on the trial results, an economic assessment has been made of the potential of forage legumes to improve the competitive edge of organic dairy systems, relative to conventional grass-based ones. Although the results suggest that the organic milk price premium plays a major role in determining the comparative profitability of organic dairy systems, the use of forage legumes also gives a significant cost advantage to organic production
On the Size of Structures in the Solar Corona
Fine-scale structure in the corona appears not to be well resolved by current
imaging instruments. Assuming this to be true offers a simple geometric
explanation for several current puzzles in coronal physics, including: the
apparent uniform cross-section of bright threadlike structures in the corona;
the low EUV contrast (long apparent scale height) between the top and bottom of
active region loops; and the inconsistency between loop densities derived by
spectral and photometric means. Treating coronal loops as a mixture of diffuse
background and very dense, unresolved filamentary structures address these
problems with a combination of high plasma density within the structures, which
greatly increases the emissivity of the structures, and geometric effects that
attenuate the apparent brightness of the feature at low altitudes. It also
suggests a possible explanation for both the surprisingly high contrast of EUV
coronal loops against the coronal background, and the uniform ``typical''
height of the bright portion of the corona (about 0.3 solar radii) in full-disk
EUV images. Some ramifications of this picture are discussed, including an
estimate (10-100 km) of the fundamental scale of strong heating events in the
corona.Comment: To appear in APJ, June 2007; as accepted Feb 200
Small and medium agility dogs alter their kinematics when the distance between hurdles differs
There is currently a lack of research examining the health and welfare implications for competitive agility dogs. The aim of this study was to examine if jump kinematics and apparent joint angles in medium (351 mm - 430 mm to the withers) and small (< 350 mm to the withers) agility dogs altered when distances between consecutive upright hurdles differ. Dogs ran a course of nine hurdles; three set at 3.6 m apart; three at 4 m apart and three at 5 m apart. Both medium (P=0.044) and small (P=0.006) dogs landed closer to the hurdle when consecutive hurdles were set at 3.6 m apart, with small dogs jumping slower at this distance (P=0.006). Results indicate that jump kinematics, but not apparent joint angles, alter when the spacing between hurdles differs. These findings may have implications for the health and welfare of agility dogs and should be used to inform future changes to rules and regulations
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