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排序方式: 共有477条查询结果,搜索用时 171 毫秒
471.
Gonçalves Mariana Gabriele Marcolino Avalos Fabio Arnaldo Pomar dos Reis Josimar Vieira Costa Milton Verdade Silva Sérgio Henrique Godinho Poggere Giovana Clarice Curi Nilton de Menezes Michele Duarte 《Precision Agriculture》2022,23(3):1027-1050
Precision Agriculture - This work proposes an approach for establishing coffee management classes mainly supported by pedological information (soil survey) and land parcels, taking into account... 相似文献
472.
Background
The native annual tobacco, Nicotiana attenuata, is found primarily in large ephemeral populations (typically for less than 3 growing seasons) after fires in sagebrush and pinyon-juniper ecosystems and in small persistent populations (for many growing seasons) in isolated washes typically along roadsides throughout the Great Basin Desert of the SW USA. This distribution pattern is due to its unusual germination behavior. Ephemeral populations are produced by the germination of dormant seeds from long-lived seed banks which are stimulated to germinate by a combination of unidentified positive cues found in wood smoke and the removal of inhibitors leached from the unburned litter of the dominant vegetation. Persistent populations may result where these inhibitors do not exist, as in washes or along disturbed roadsides. To determine if this germination behavior has influenced population structure, we conducted an AFLP (244 individuals), ISSR (175 individuals) and ISSR+ AFLP (175 individuals) analysis on plants originating from seed collected from populations growing in 11 wash and burns over 11 years from the SW USA.Results
Genetic variance as measured by both ISSR and AFLP markers was low among sites and comparatively higher within populations. Cluster analysis of the Utah samples with samples collected from Arizona, California, and Oregon as out-groups also did not reveal patterns. AMOVA analysis of the combined AFLP and ISSR data sets yielded significantly low genetic differentiation among sites (Φct), moderate among populations within sites (Φsc) and higher genetic differentiation within populations (Φst).Conclusions
We conclude that the seed dormancy of this post-fire annual and its resulting age structure in conjunction with natural selection processes are responsible for significantly low among sites and comparatively high within-population genetic variation observed in this species. 相似文献473.
Bauder Javan M. Chandler Houston C. Elmore Michele L. Jenkins Christopher L. 《Landscape Ecology》2022,37(10):2519-2533
Landscape Ecology - Wildlife distributions are often subdivided into discrete conservation units to aid in implementing management and conservation objectives. Habitat suitability models,... 相似文献
474.
OBJECTIVE: Among adults with diabetes attempting to change their own diets, we explored how these adults approached providing food for their children and how their children reacted to dietary changes in the household. DESIGN: The research design used semi-structured parallel individual interviews of adults and a child (aged 10-17 years) in their home. Interviews were audio-taped, transcribed, coded and analysed for themes. SUBJECTS: Subjects included families in which one inner-city African American or Latino adult with diabetes had completed a diabetes intervention promoting healthy dietary behaviours. RESULTS: We completed 29 interviews (14 adult-child pairs and one child). Adults approached making dietary changes for themselves and also providing food for their family in different ways, ranging from expecting everyone to eat the same thing to preparing two separate meals. Many children resisted dietary changes while fewer acquiesced. Among children who went along with changes, some reported resisting initially then adjusting, while others did not resist because the food still tasted good or they could obtain preferred foods outside the house. The intersection of adults' meal strategies and children's reactions to the changes can be used to categorise families into different patterns. These patterns highlight the tension between an adult who must make dietary changes to control diabetes and a child who is not necessarily motivated to change. CONCLUSION: From this framework we suggest hypotheses about how these patterns might influence dietary behaviour in adults and children. Understanding these patterns could guide interventions to assist parents in successfully including children in their dietary changes. 相似文献
475.
Tsachaki M Gady AL Kalopesas M Linforth RS Athès V Marin M Taylor AJ 《Journal of agricultural and food chemistry》2008,56(13):5308-5315
On the basis of a mechanistic model, the overall and liquid mass transfer coefficients of aroma compounds were estimated during aroma release when an inert gas diluted the static headspace over simple ethanol/water solutions (ethanol concentration = 120 mL x L(-1)). Studied for a range of 17 compounds, they were both increased in the ethanol/water solution compared to the water solution, showing a better mass transfer due to the presence of ethanol, additively to partition coefficient variation. Thermal imaging results showed differences in convection of the two systems (water and ethanol/water) arguing for ethanol convection enhancement inside the liquid. The effect of ethanol in the solution on mass transfer coefficients at different temperatures was minor. On the contrary, at different headspace dilution rates, the effect of ethanol in the solution helped to maintain the volatile headspace concentration close to equilibrium concentration, when the headspace was replenished 1-3 times per minute. 相似文献
476.
Evaluation of osseous‐associated cervical spondylomyelopathy in dogs using kinematic magnetic resonance imaging
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Michele Provencher Amy Habing Sarah A. Moore Laurie Cook Gary Phillips Ronaldo C. da Costa 《Veterinary radiology & ultrasound》2017,58(4):411-421
Osseous‐associated cervical spondylomyelopathy in dogs is characterized by both static and dynamic spinal cord compression; however, standard MRI methods only assess static compression. In humans with cervical spondylotic myelopathy, kinematic MRI is commonly used to diagnose dynamic spinal cord compressions. The purpose of this prospective, analytical study was to evaluate kinematic MRI as a method for characterizing the dynamic component of osseous‐associated cervical spondylomyelopathy in dogs. We hypothesized that kinematic MRI would allow visualization of spinal cord compressions that were not identified with standard imaging. Twelve client‐owned dogs with osseous‐associated cervical spondylomyelopathy were enrolled. After standard MRI confirmed a diagnosis of osseous‐associated cervical spondylomyelopathy, a positioning device was used to perform additional MRI sequences with the cervical vertebral column flexed and extended. Morphologic and morphometric (spinal cord height, intervertebral disc width, spinal cord width, vertebral canal height, and spinal cord area) assessments were recorded for images acquired with neutral, flexion, and extension imaging. A total of 25 compressions were seen with neutral positioning, while extension identified 32 compressions. There was a significant association between extension positioning and presence of a compressive lesion at C4‐C5 (p = 0.02). Extension was also associated with a change in the most severe site of compression in four out of 12 (33%) dogs. None of the patients deteriorated neurologically after kinematic imaging. We concluded that kinematic MRI is a feasible method for evaluating dogs with osseous‐associated cervical spondylomyelopathy, and can reveal new compressions not seen with neutral positioning. 相似文献
477.
The effect of crate height on the behavior of female turkeys during commercial pre‐slaughter transportation
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Guido Di Martino Katia Capello Anna Lisa Stefani Luca Tripepi Angelica Garbo Marina Speri Matteo Trolese Michele Brichese Stefano Marangon Lebana Bonfanti 《Animal Science Journal》2017,88(10):1651-1657
Limited information is available on suitable height of transport crates for turkeys. We compared behaviors and physiological indicators of four groups of 10 female turkeys each confined in either conventional (38.5 cm height) or experimental (77 cm height) crates during six commercial pre‐slaughter transportations for 86 km (76 ± 4 min) along two tracts with one‐lane streets, crossroads, bends, roundabouts (S1 and S2) and a highway tract (H) between S1 and S2. Only 36% of birds in the higher crates maintained a standing position. In conventional versus experimental crates, the frequency of rising attempts was five/bird/hour versus less than one/bird/hour, while wing flapping was seven/bird/hour versus 20/bird/hour, and balance loss was one versus four/bird/hour. The behaviors of both groups differed significantly according to the route tract, with a lower frequency of stress‐related behaviors at H. No scratches, fractures or hematomas were detected in any birds after transportation. Crate height had no significant effect on hemato‐biochemical markers. These results suggest that crates enabling a standing position may increase potentially dangerous behaviors. Moreover, busy and curvy routes should be avoided, as they may contribute to increasing the frequency of stress‐related behaviors. 相似文献