scholarly journals Modeling the Influence of Forest Structure on Microsite Habitat Use by Snowshoe Hares

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Angela K. Fuller ◽  
Daniel J. Harrison
Keyword(s):  
Structural Characteristics ◽  
Canopy Closure ◽  
North Central ◽  
Management Guidelines ◽  
Information Theoretic ◽  
Important Prey ◽  
Snowshoe Hares ◽  
Pellet Density ◽  
Northern Forests ◽  
And Function

Snowshoe hare (Lepus americanus) is an important prey species for many Carnivora and has strong influences on community structure and function in northern forests. An understanding of within-stand (microsite) forest structural characteristics that promote high use by hares is important to provide forest management guidelines. We measured forest structural characteristics at the microsite-scale in north-central Maine and used an information-theoretic modeling approach to infer which characteristics were most strongly associated with use by hares during winter. We measured overwinter hare pellet density to model relationships among microsite-scale vegetation structure and hare use. Overwinter pellet density was positively associated with live stem cover (3 × coniferous saplings + deciduous saplings) and negatively associated with overstory canopy closure; the two variables explained 71% of the variation in microsite use by hares. The highest pellet densities were in grids with canopy closure <72% and stem cover units >22,000 stems/ha. Silvicultural practices that create dense areas of conifer and deciduous saplings should receive high within-stand use by hares in winter. These conditions can be achieved by promoting the release of advanced regeneration and reducing overstory cover to encourage establishment of shade-intolerant species; clearcutting is one such silvicultural prescription to achieve these conditions.

Monthly Weights of Snowshoe Hares From North-Central Alberta

1959 ◽  
Vol 40 (2) ◽  
pp. 221-226 ◽  
Author(s):  
W. Rowan ◽  
L. B. Keith
Keyword(s):  
North Central ◽  
Snowshoe Hares

Attributes of forest strips used by snowshoe hare in winter within clear-cut boreal landscapes

2005 ◽  
Vol 35 (10) ◽  
pp. 2521-2527 ◽  
Author(s):  
François Potvin ◽  
Normand Bertrand ◽  
Jean Ferron
Keyword(s):  
Abies Balsamea ◽  
Basal Area ◽  
Balsam Fir ◽  
Snowshoe Hare ◽  
Forest Patches ◽  
Clear Cut ◽  
Important Prey ◽  
South Central ◽  
Snowshoe Hares ◽  
Riparian Strips

The snowshoe hare (Lepus americanus Erxleben) is an important prey for many predators in the boreal forest. In this biome, clear-cut landscapes are generally large and consist of aggregated cutting blocks separated by narrow forest strips (typically 60–100 m wide). To identify attributes of forest strips that are important for snowshoe hares, we measured the use of strips using track counts over two winters in six clear-cut landscapes (23–256 km2) in south-central Quebec. Surveys were conducted in 20 riparian strips (RS), 20 upland strips (US), and 15 control sites (CO) at the periphery of clear-cut landscapes. Overall, 392 signs of hare presence were recorded along 50 km of transects. Snowshoe hares were present in one-third of the strips surveyed and were five times less abundant in US and RS than in CO. The species avoided strip edges. Hares were more common in the wider strips (>100 m), in the strips adjacent to residual forest patches (≥25 ha), or in those having a denser shrub canopy, which is often associated with a greater basal area in balsam fir (Abies balsamea (L.) Mill.). To maintain snowshoe hare at moderate densities in large clear-cut landscapes, we suggest leaving uncut forest strips >100 m wide in areas having a good shrub cover with presence of balsam fir.

scholarly journals Structural Characteristics Are Not Associated With Pain and Function in Rotator Cuff Tears

2015 ◽  
Vol 3 (5) ◽  
pp. 232596711558459 ◽  
Author(s):  
Emily J. Curry ◽  
Elizabeth E. Matzkin ◽  
Yan Dong ◽  
Laurence D. Higgins ◽  
Jeffrey N. Katz ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Structural Characteristics ◽  
Rotator Cuff Tears ◽  
And Function

Myogenic, mechanical and structural characteristics of resistance arterioles from healthy and ischaemic subjects

2003 ◽  
Vol 105 (6) ◽  
pp. 683-689 ◽  
Author(s):  
P. COATS
Keyword(s):  
Mechanical Properties ◽  
Internal Control ◽  
Regional Blood Flow ◽  
Structural Characteristics ◽  
Critical Limb Ischaemia ◽  
Myogenic Tone ◽  
Limb Ischaemia ◽  
Active Pressure ◽  
Chemical Stimuli ◽  
And Function

In critical limb ischaemia (CLI), the ability to regulate regional blood flow in the diseased portion of the leg would appear to be severely compromised. Considering this, pressure-dependent myogenic and mechanical properties of resistance arterioles isolated from control subjects and from patients with CLI were studied. Using confocal microscopy and pressure myography, subcutaneous resistance arteriole structure and function were compared between subcutaneous arterioles isolated from healthy volunteers [control subcutaneous (CS)] and non-diseased proximal subcutaneous (PS; internal control) and distal subcutaneous (DS) arterioles from the diseased ischaemic part of the limb from patients with CLI. Significant wall atrophy was observed in DS arterioles compared with PS and CS arterioles. Passive pressure-dependent mechanical properties were significantly altered in the diseased arterioles compared with PS and CS arterioles. Active pressure-dependent myogenic tone was completely absent in DS arterioles. The atrophic structural remodelling in DS arterioles were correlated with the changes in vascular mechanics, but not with the ability of these arterioles to contract in response to chemical stimuli. However, active pressure-dependent myogenic tone was absent in the DS arterioles. The combination of altered pressure-dependent passive mechanical and active myogenic tone goes some way in explaining CLI sequelae and poor outcome following surgical revascularization experienced by these patients.

scholarly journals In Vitro Selection of Integration Host Factor Binding Sites

1999 ◽  
Vol 181 (10) ◽  
pp. 3246-3255 ◽  
Author(s):  
Steven D. Goodman ◽  
Nerissa J. Velten ◽  
Qian Gao ◽  
Scott Robinson ◽  
Anca M. Segall
Keyword(s):  
Binding Sites ◽  
In Vitro Selection ◽  
Structural Characteristics ◽  
Integration Host Factor ◽  
Host Factor ◽  
Binding Domain ◽  
Physical Constraints ◽  
Individual Sequences ◽  
And Function

ABSTRACT Integration host factor (IHF) is a bacterial protein that binds and severely bends a specific DNA target. IHF binding sites are approximately 30 to 35 bp long and are apparently divided into two domains. While the 3′ domain is conserved, the 5′ domain is degenerate but is typically AT rich. As a result of physical constraints that IHF must impose on DNA in order to bind, it is believed that this 5′ domain must possess structural characteristics conducive for both binding and bending with little regard for specific contacts between the protein and the DNA. We have examined the sequence requirements of the 5′ binding domain of the IHF binding target. Using a SELEX procedure, we randomized and selected variants of a natural IHF site. We then analyzed these variants to determine how the 5′ binding domain affects the structure, affinity, and function of an IHF-DNA complex in a native system. Despite finding individual sequences that varied over 100-fold in affinity for IHF, we found no apparent correlation between affinity and function.

scholarly journals A Concise Review on the Molecular Structure and Function Relationship of β-Glucan

2019 ◽  
Vol 20 (16) ◽  
pp. 4032 ◽  
Author(s):  
Bin Du ◽  
Maninder Meenu ◽  
Hongzhi Liu ◽  
Baojun Xu
Keyword(s):  
Molecular Structure ◽  
Functional Food ◽  
Structural Characteristics ◽  
Textural Properties ◽  
High Viscosity ◽  
Biological Properties ◽  
Food Ingredient ◽  
And Function ◽  
Relationship Of ◽  
The Relationship

β-glucan is a non-starch soluble polysaccharide widely present in yeast, mushrooms, bacteria, algae, barley, and oat. β-Glucan is regarded as a functional food ingredient due to its various health benefits. The high molecular weight (Mw) and high viscosity of β-glucan are responsible for its hypocholesterolemic and hypoglycemic properties. Thus, β-glucan is also used in the food industry for the production of functional food products. The inherent gel-forming property and high viscosity of β-glucan lead to the production of low-fat foods with improved textural properties. Various studies have reported the relationship between the molecular structure of β-glucan and its functionality. The structural characteristics of β-glucan, including specific glycosidic linkages, monosaccharide compositions, Mw, and chain conformation, were reported to affect its physiochemical and biological properties. Researchers have also reported some chemical, physical, and enzymatic treatments can successfully alter the molecular structure and functionalities of β-glucan. This review article attempts to review the available literature on the relationship of the molecular structure of β-glucan with its functionalities, and future perspectives in this area.

scholarly journals Visitations by Snowshoe Hares (Lepus americanus) to and Possible Geophagy of Materials from an Iron-Rich Excavation in North-Central British Columbia

2013 ◽  
Vol 127 (1) ◽  
pp. 26 ◽  
Author(s):  
Roy V. Rea ◽  
Christina L. Stumpf ◽  
Dexter P. Hodder
Keyword(s):  
British Columbia ◽  
North America ◽  
Fecal Pellet ◽  
Nutritional Stress ◽  
Lepus Americanus ◽  
North Central ◽  
Snowshoe Hares ◽  
Mineral Licks ◽  
Excavation Site

Fecal pellet samples and photo data were collected and analyzed to investigate the suspected occurrence of geophagy of soils by Snowshoe Hares (Lepus americanus) at a small iron-rich mineral excavation in north-central British Columbia. Pellet samples from Snowshoe Hares collected near the excavation site in both February 2004 and 2005 showed higher levels of iron (II) sulphate in pellets than in samples from control areas (P < 0.05). Using remote wildlife camera technology, we determined that Snowshoe Hares accounted for 72% of visits by mammals to the site. Ninety percent of these visits occurred at night; this timing corresponds with the use of mineral licks by several other species of mammals in North America. Use occurred in winter (49%) and spring (47%), but was rare in summer and autumn, and may have coincided with periods of nutritional stress in Snowshoe Hares.

A comparative structural analysis of sepiapterin reductase from Drosophila by homology modeling

Pteridines ◽  
2015 ◽  
Vol 26 (2) ◽  
pp. 55-61 ◽  
Author(s):  
Kiyoung Kim ◽  
Keon-Hyoung Song ◽  
Jeongbin Yim
Keyword(s):  
Homology Modeling ◽  
Structural Characteristics ◽  
Valuable Insight ◽  
Gene Encoding ◽  
Sepiapterin Reductase ◽  
Modeling Analysis ◽  
Different Shapes ◽  
And Function

AbstractSepiapterin reductase (SR) catalyzes the final steps of BH4 biosynthesis. Previously, a gene encoding SR has been cloned and characterized from a Drosophila cDNA library in vitro. The present study reports the identification of another SR gene in the Drosophila genome and the structural characteristics and differences of the two Drosophila SRs, using homology modeling analysis. Homology modeling of SRs for protein structure and function prediction showed that the two SRs have different surface electrostatic distributions and different shapes of the substrate (sepiapterin)-binding sites. These results provide valuable insight into the possibility of diverse functions of Drosophila SRs in vivo.

Lightweight Design for Thin-Walled Cylindrical Shell Based on Action Mechanism of Bamboo Node

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Denghai Xing ◽  
Wuyi Chen ◽  
Dengjiang Xing ◽  
Tuo Yang
Keyword(s):  
Cylindrical Shell ◽  
Design Method ◽  
Structural Characteristics ◽  
Lightweight Design ◽  
Experimental Models ◽  
Action Mechanism ◽  
Engineering Structures ◽  
Thin Walled ◽  
And Function ◽  
Design Ideas

Lightweight design is needed for many engineering structures, but conventional design methods cannot always meet requirements. Natural organisms have developed many types of structures with excellent properties and ingenious construction, and they can provide many new design ideas. In this paper, a thin-walled cylindrical shell, one of the most common structures, is designed to resist buckling based on the study of bionics. First, the structure and function of bamboo node are described, and a statistical analysis of internode length-to-diameter ratio in bamboo is performed to investigate structural characteristics of bamboo node. Then, through buckling analysis of three relevant experimental models, the action mechanism of bamboo node is investigated, and two rules for application of this structure in engineering are proposed. Finally, a bionic design method is introduced, and a lightweight design for a thin-walled cylindrical shell based on this method is presented. A comparison between the bionic shell and a conventional one shows that the weight was reduced by as much as 20.5%.

Sign in / Sign up

Export Citation Format

Share Document