13,126 research outputs found
Use of biological reference points for the conservation of atlantic salmon (Salmo salar L.)in the River Lune, North West England.
This paper deals with the development and use of biological reference points for salmon conservation on the River Lune, England. The Lune supports recreational and net fisheries
with annual catches in the region of 1,000 and 1356 salmon respectively. Using models transported from other river systems, biological reference points exclusive to the Lune were developed; specifically the number of eggs deposited and carrying capacity estimates for age 0+ and 1+ parr. The conservation limit was estimated at 11.9 million eggs and between 1989 and 1998 was exceeded in two years. Comparison of juvenile salmon densities in 1991 and 1997 with estimates of carrying capacity indicated that 0+ and 1+ parr densities were at around 60 % of carrying capacity and may relate to the number of eggs deposited in 1990 and
1996 being approximately 70% of the target value.
The paper discusses the management actions taken in order to ensure that the management target of the conservation limit being met four years out of five is delivered. It also discusses the balance between conservation and exploitation and the socio-economic decisions made in
order to ensure parity of impacts on the rod and net fisheries. The regulations have been enforced since 1999 and the paper concludes with an assessment of the actions taken to deliver the management targets, over the last five years
Measurement of the Average Time-Integrated Mixing Probability of b-Flavored Hadrons Produced at the Tevatron
Coplanar Circumbinary Debris Disks
We present resolved Herschel images of circumbinary debris disks in the alpha
CrB (HD139006) and beta Tri (HD13161) systems. We find that both disks are
consistent with being aligned with the binary orbital planes. Though secular
perturbations from the binary can align the disk, in both cases the alignment
time at the distances at which the disk is resolved is greater than the stellar
age, so we conclude that the coplanarity was primordial. Neither disk can be
modelled as a narrow ring, requiring extended radial distributions. To satisfy
both the Herschel and mid-IR images of the alpha CrB disk, we construct a model
that extends from 1-300AU, whose radial profile is broadly consistent with a
picture where planetesimal collisions are excited by secular perturbations from
the binary. However, this model is also consistent with stirring by other
mechanisms, such as the formation of Pluto-sized objects. The beta Tri disk
model extends from 50-400AU. A model with depleted (rather than empty) inner
regions also reproduces the observations and is consistent with binary and
other stirring mechanisms. As part of the modelling process, we find that the
Herschel PACS beam varies by as much as 10% at 70um and a few % at 100um. The
70um variation can therefore hinder image interpretation, particularly for
poorly resolved objects. The number of systems in which circumbinary debris
disk orientations have been compared with the binary plane is now four. More
systems are needed, but a picture in which disks around very close binaries
(alpha CrB, beta Tri, and HD 98800, with periods of a few weeks to a year) are
aligned, and disks around wider binaries (99 Her, with a 50 yr period) are
misaligned, may be emerging. This picture is qualitatively consistent with the
expectation that the protoplanetary disks from which the debris emerged are
more likely to be aligned if their binaries have shorter periods.Comment: accepted to MNRA
Protein Assimilation, Usage and Storage
Common concerns among athletes regarding protein consumption are the following: what protein type(s) is best suited for their particular needs; what amounts of protein should be consumed for their supplementation; and lastly, what should the timing of protein consumption be, for prime utilization in the body? There is a recommended daily allowance (RDA) by the National Institute of Health (NIH). The NIH recommends that an individual should be ingesting 0.8g/kg of body weight a day. Active individuals who include resistance training into their daily regime may need more than the RDA. The purpose of this study is to determine if 4.4 grams of protein per kilogram of body weight for is adequate, inadequate or in excess for the body to utilize for recovery or muscle hypertrophy during a five (5) week training intervention. This study utilized 2 male subjects that volunteered and were considered trained athletes with a minimum of one-year experience in lifting weights. Prior to testing, each subject signed an informed consent form approved by the Institutional Review Board (IRB) for humans as subjects at Midwestern State University and a physical activity readiness questionnaire (PAR-QTM). Resting measures included: height (cm), weight (kg), body fat analysis through skinfold (3 site, %), anthropometric circumference measures at the abdomen, biceps, hips, gastrocnemius, forearm, upper thigh, mid-thigh and waist. During the intervention, each subject was given 4.4 g/kg/day of protein based on a daily nutritional analysis and supplementation of whey protein. Pre and post strength tests were the following: 1 repetition maximal (RM) bench press, latissimus pull down, squat, leg extension and leg curl. After a 5-week intervention with protein and supervised weight training sessions, all results were recorded and analyzed. Averages from every exercise from each week were charted to be analyzed to see progress throughout the intervention and compared to one another. For both subjects, body weight and all circumference measures increased after the 5 week intervention of training and high protein intake. Additionally, body fat percentage was reduced in both subjects following the intervention. Strength improvements through 1RM testing was shown in both subjects for the following: latissimus pull down, squat, leg extension and leg curl. It is concluded that a 5 week intervention of training and high protein intake facilitates strength and lean muscle mass
Search for long lived charged massive particles in pp collisions at s-hat = 1.8TeV
We report a search for the production of long-lived charged massive particles in a data sample of 90 pb-1 of √s=1.8 TeV pp̅ collisions recorded by the Collider Detector at Fermilab. The search uses the muonlike penetration and anomalously high ionization energy loss signature expected for such a particle to discriminate it from backgrounds. The data are found to agree with background expectations, and cross section limits of O(1) pb are derived using two reference models, a stable quark and a stable scalar lepton
Evidence for dust accumulation just outside the orbit of Venus
To contribute to the knowledge of dynamics of interplanetary dust we are
searching for structures in the spatial distribution of interplanetary dust
near the orbit of Venus. To this end we study the radial gradient of zodiacal
light brightness, as observed by the zodiacal light photometer on board the
Helios space probes on several orbits from 1975 to 1979. The cleanest data
result from Helios B (= Helios 2) launched in January 1976. With respect to the
general increase of zodiacal light brightness towards the Sun, the data show an
excess brightness of a few percent for positions of the Helios space probe just
outside the orbit of Venus. We consider this as evidence for a dust ring
associated with the orbit of Venus, somewhat similar to that found earlier
along the Earth's orbit.Comment: 7 pages, 8 figures, Astronomy&Astrophysics, accepte
Discovery of the Fomalhaut C debris disc
Fomalhaut is one of the most interesting and well studied nearby stars,
hosting at least one planet, a spectacular debris ring, and two distant
low-mass stellar companions (TW PsA and LP 876-10, a.k.a. Fomalhaut B & C). We
observed both companions with Herschel, and while no disc was detected around
the secondary, TW PsA, we have discovered the second debris disc in the
Fomalhaut system, around LP 876-10. This detection is only the second case of
two debris discs seen in a multiple system, both of which are relatively wide
(3000 AU for HD 223352/40 and 158 kAU [0.77 pc] for Fomalhaut/LP
876-10). The disc is cool (24K) and relatively bright, with a fractional
luminosity , and represents the rare
observation of a debris disc around an M dwarf. Further work should attempt to
find if the presence of two discs in the Fomalhaut system is coincidental,
perhaps simply due to the relatively young system age of 440 Myr, or if the
stellar components have dynamically interacted and the system is even more
complex than it currently appears.Comment: Published in MNRAS Letters. Merry Xma
Evaluating voices of youth: a violence prevention program
Faced with rising rates of youth violence in Philadelphia, the United States’ Attorney’s Office for the Eastern District of Pennsylvania developed a program designed to help youth tell their stories related to violence and to take a role in violence prevention. Youth from five different schools worked with two filmmakers over a three-month period and created films that discussed the impact violence had on their lives. The program provided an exploratory look into creative outlets for cathartic expression. Several lessons learned during the development and implementation of the program can be used for other organizations planning youth violence prevention programs
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