3,114 research outputs found
Strategy for Mitigating Collision Between Landsat-5 and the Afternoon Constellation
The NASA Goddard Space Flight Center Earth Science Mission Operations project, the French space agency Centre National d tudes Spatiales, the Argentinian space agency Comisi n Nacional de Actividades Espaciales, and the United States Geological Survey all operate spacecraft in sun-synchronous frozen orbits. The orbits are planned to not place any of the spacecraft at risk of colliding with another. However, evolution of these orbits over time has com-promised the safe interaction between Landsat-5 and the Afternoon Constella-tion. This paper analyzes the interactions between the Landsat-5 spacecraft and the Afternoon Constellation members over a period of 6 years, describing the current risk and plan to mitigate collisions in the future
Botanicals for Pigs—Goldenseal
Various botanical products have been suggested to have beneficial effects as a replacement for manmade chemotherapeutic and antibacterial agents. This study evaluated four levels of goldenseal (0.0 to 1.0%) compared with a control diet control diet containing Mecadox for nursery pigs. Although not performing to the level of the Mecadox control, pigs on the 0.25 and 1.00% goldenseal diets generally performed better than ones on the 0.00 and 0.05% goldenseal diets and were often not statistically different from the Mecadox control pigs. Increasing levels of goldenseal did not influence the muscle characteristics evaluated
Botanicals for Pigs—Peppermint
Botanicals have been proposed as a substitute for antimicrobials in swine diets because of their natural antibacterial activity. Peppermint, a botanical that grows in Iowa, was compared with a standard antibacterial nursery dietary regimen. Performance of pigs on all treatments was similar, including the positive and negative controls. At the tested inclusion levels (0, 0.5, 2.5, and 5.0%), no statistical advantage existed over the 5-week study when compared with a positive control diet with 50 g/ton Mecadox or with a negative control containing no antibacterial inclusions. Increasing levels of peppermint did not influence the muscle characteristics evaluated
Botanicals for Pigs—Echinacea
Botanicals have been proposed as a substitute for antimicrobials in swine diets because of their natural antibacterial activity. Echinacea, a botanical that grows in Iowa, was compared with a standard antibacterial nursery dietary regimen. At the tested inclusion levels (0.1, 0.5 and 2.0%) no statistical advantage existed when compared with a positive control diet with 50 g/ton Mecadox or with a negative control containing no antibacterial inclusions. Echinacea-treated pigs exhibited a slight, but not objectionable, off-flavor compared with noninclusion levels. Higher levels of Echinacea inclusions may be required to enhance growth rate and feed efficiency swine production
Botanicals for Pigs—Garlic
Botanicals have been proposed as a substitute for antimicrobials in swine diets because of their natural antibacterial activity. Garlic, a botanical that grows in Iowa, was compared with a standard antibacterial nursery dietary regimen. At the tested inclusion levels (0.5, 2.5 and 5%) increasing levels of garlic generally depressed feed intake and average daily gain in nursery pigs and depressed performance compared with the positive control diet with Mecadox. Muscle samples from the garlic-fed pigs all had very objectionable or extremely objectionable off-flavors.
Results of the Apogee-Raising Campaign of the Magnetospheric Multiscale Mission
This paper describes the apogee-raising campaign of the Magnetospheric Multiscale mission, where the spacecraft increased their apogee radii from 12 to 25 Earth radii in a total of 98 maneuvers. These maneuvers included an initial formation resize set to spread the spacecraft apart for safety, 32 apogee-raise delta-v maneuvers, their associated slews, four perigee-raise maneuvers and the associated slews, and finally a set of maneuvers to get back into formation. These activities were all accomplished successfully and on schedule with no anomalies, and at a fuel consumption somewhat less than predicted. As a result, MMS was set up ready to carry out in situ studies of magnetic reconnection in the magnetotail, with sufficient fuel remaining for a significant extended mission
Botanicals as part of an integral value-added pork production system
Selected herbs are known to naturally possess antibacterial and other characteristics that could be useful in animal protein production. Inclusion of these herbs in animal feeds as alternative growth promotion and efficiency stimulants may be able to address some of the current concerns about the possibility of significant antibiotic-resistant bacteria development that stems from drugs currently used at subtherapeutic levels in animal production. Several herbs were tested for their ability to aid animal growth rates and feed efficiency without giving rise to antibiotic-resistant microbes
Rapid Muscle Activation Changes Across a Competitive Collegiate Female Soccer Season
Objective: The purpose of this study was to examine the effects of a competitive soccer season on rapid activation properties of the knee extensors and flexors in Division II female soccer players. Methods: Eighteen collegiate female soccer players participated in the present study, however, due to injuries during the season a final sample of 16 players were included for study analysis. Participants performed two maximal voluntary isometric contractions (MVICs) of the knee extensors and flexors before, during, and at the end of a competitive college soccer season. Electromyography root mean square (EMG RMS; μV), rate of EMG rise (RER; %Peak EMG•s-1), and electromechanical delay (EMD; ms) were examined on both legs for the knee extensors and flexors. Results: EMG RMS at early time intervals (0-50, 0-100, and 50-100 ms) and RER at 0-75 ms for the knee extensors and flexors significantly increased from the pre-season to the end of the season (P ≤ 0.010-0.026, η2=0.36-0.81). EMD of the knee flexors significantly decreased at the mid-season and the end of the season compared to the pre-season (P \u3c 0.001, η2=0.95). Conclusions: These findings may have important implications for monitoring improvements on thigh neuromuscular activation and developing lower extremity injury prevention strategies during a competitive collegiate female soccer season
Age-Related Differences in Vertical Jump Power and Muscle Size and Quality of the Vastus Lateralis
Previous studies have reported that decreases in muscle size and quality of the vastus lateralis (VL) may contribute to the lower vertical jump power observed in old compared to young males. However, we are aware of no previous studies that have examined the contribution of VL muscle size and quality to age-related power differences in females, nor have there been any studies that examined these differences between young, middle, and older age groups. PURPOSE: To determine the effects of age on vertical jump power and muscle size (cross-sectional area [CSA]) and quality (echo intensity [EI]) of the VL in young, middle-aged, and old females. METHODS: Twenty-six young (age = 22 ± 2 yr; height = 163 ± 7 cm; mass = 61 ± 8 kg), 30 middle-aged (36 ± 5 yr; 164 ± 7 cm; 62 ± 11 kg), and 23 old (71 ± 5 yr; 161 ± 5 cm; 59 ± 10 kg) females underwent two diagnostic ultrasound assessments followed by three countermovement vertical jumps (CMJs). Peak power output (Pmax; W) was measured during the CMJs using a portable force plate. VL CSA (cm2) and EI (AU) were measured on the right leg using a portable B-mode ultrasound imaging device and linear-array probe. One-way ANOVAs and post-hoc analyses were used to compare Pmax, CSA, and EI between age groups. Pearson product-moment correlation coefficients (r) were used to examine the relationships between Pmax and CSA and EI. RESULTS: Higher Pmax and CSA values were observed for the young (Pmax = 2257.40 ± 438.42 W; CSA = 20.59 ± 4.23 cm2) compared to the old (Pmax = 1098.55 ± 242.10 W; CSA = 10.69 ± 2.47 cm2) and middle-aged (Pmax = 1958.20 ± 341.87 W; CSA = 18.05 ± 4.24 cm2) and the middle-aged compared to the old (P ≤ 0.001-0.039). EI values for the young (104.29 ± 16.86 AU) and middle-aged (107.71 ± 17.30 AU) were lower than the old (128.35 ± 14.99 AU) (P \u3c 0.001), but they were not different from each other (P = 0.720). There was a significant positive relationship between Pmax and CSA (r = 0.830; P \u3c 0.001) and a significant negative relationship between Pmax and EI (r = -0.442; P \u3c 0.001). CONCLUSION: These findings demonstrated that vertical jump power and muscle size and quality decrease with age. The significant relationships observed between Pmax and CSA and EI perhaps suggest that these age-related declines in VL muscle size and quality may play an important role in the lower vertical jump power observed in middle-aged and older adults
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