8,441 research outputs found
Next steps for understanding the selective relevance of female-female competition
After decades of neglect, recent empirical
research on exaggerated female traits
(e.g., ornaments, armaments, aggression,
acoustic signals, etc.) has revived interest
in this widespread but poorly understood
phenomenon, and shown that these traits
often function in the context of female-female
competition (West-Eberhard,
1983; Amundsen, 2000; Clutton-Brock,
2009; Rosvall, 2011a; Stockley and Bro-Jørgensen,
2011; Rubenstein, 2012 [Theme
issue]; Stockley and Campbell, 2013
[Theme issue]). However, recent reviews
have emphasized the applicability of sexual
vs. social selection, rather than rigorously
examining the role of different ecological
contexts in shaping the evolution of traits
used in competitive contexts (hereafter,
“competitive traits”) in females. Thus,
we still lack a solid understanding of
the ecological and evolutionary mechanisms
driving the evolution of female trait
expression, in particular whether, how,
and why these mechanisms vary among
species, and between the sexes
Phase diagram of the three-dimensional Anderson model of localization with random hopping
We examine the localization properties of the three-dimensional (3D) Anderson
Hamiltonian with off-diagonal disorder using the transfer-matrix method (TMM)
and finite-size scaling (FSS). The nearest-neighbor hopping elements are chosen
randomly according to . We find that the
off-diagonal disorder is not strong enough to localize all states in the
spectrum in contradistinction to the usual case of diagonal disorder. Thus for
any off-diagonal disorder, there exist extended states and, consequently, the
TMM converges very slowly. From the TMM results we compute critical exponents
of the metal-insulator transitions (MIT), the mobility edge , and study
the energy-disorder phase diagram.Comment: 4 pages, 5 EPS figures, uses annalen.cls style [included]; presented
at Localization 1999, to appear in Annalen der Physik [supplement
OGO-2 Magnetic Field Observations During the Magnetic Storm of March 13-15, 1966
Magnetic disturbances examined for correlation of surface and satellite magnetic field measurement
Short and long distance translocations: Movement and survival in eastern box turtles (_Terrapene carolina carolina_)
*Background/Question/Methods*

Human development represents a serious threat to wildlife populations through continued habitat loss and incidental mortality from construction activities. Resource managers responsible for protecting species with legal status or high public profile are faced with difficult decisions on how to best manage populations located in construction zones. One approach to mitigate mortalities is to relocate individuals. The effectiveness of translocation for reptiles and amphibians has been questioned, with studies often reporting higher mortality and increased movements of translocated individuals. Translocations of reptiles and amphibians have primarily involved moving animals long distances, well beyond an individual’s home range. For reptiles this means finding new nesting, foraging, and overwintering sites, which may be problematic. Moving individuals only short distances, within their home range, may reduce those problems. As part of the mitigation plan for a highway construction project in central Maryland, groups of eastern box turtles (Terrapene carolina carolina) were translocated both short distances (<0.5km), and long distances (~5km). To investigate differences in survival and movement patterns among long distance translocation, short distance translocation, and non-translocation groups, I tracked 94 turtles (31 long distance translocation, 29 short distance translocation, and 34 non-translocation) using radio telemetry. 

*Results/Conclusions*

Eleven animals died during the first activity season after translocation (April through November 2008). The mortalities included two long distance translocation, six short distance translocation, and three non-translocation animals. The causes of mortality included road kill, construction activity, and unknown (1, 4, and 6 mortalities respectively). All construction related mortalities were a result inadequate exclusion fencing to keep turtles from trespassing back onto the construction site. All mortalities due to construction were either non-translocation or short distance translocation animals. Eleven other individuals were located at least once within the construction zone, suggesting that without our intervention mortality rates would have been much higher. Preliminary results for movement show that turtles in the non-translocation group had the lowest average movements while long distance translocation animals had the greatest average movements. Long distance translocation turtles also chose overwintering sites farther away from their initial overwintering sites than either short distance translocation or non-translocation turtles (average distance from original site of 261.8m, 155.6m, and 124.3m respectively). This suggests that movement patterns of short distance translocation turtles are more like native turtles.

Certain floristic affinities of the trees and shrubs of the Great Smoky mountains and vicinity
It is widely admitted that the forests of eastern United States reach their culmination in the southern Appalachians, particularly in the Unaka range of North Carolina and Tennessee. It is in the mountains of this range that the greatest height east of the Rocky mountains is reached; in the Black mountains with Mt. Mitchell, the Craggy mountains and the Great Smoky mountains, with some forty peaks over 6,000 feet in altitude, and with Mt. Guyot and Clingman\u27s Dome topping them all. Here on these lofty peaks (for many of them rise over a mile in altitude above their base), in a region of high rainfall and high humidity, there is rich flora -- rich in species and rich in numbers
An ecological study of the heath balds of the Great Smoky mountains
The inhabitants of the Great Smoky mountains usually refer to the heath communities under consideration as slicks or balds. The former name is derived from the smooth appearance they present on the ridges and mountain tops when viewed from a distance and which is entirely misleading, for they are extremely rough and tangled. The name bald refers to the absence of trees, these areas being exclusively occupied by shrubs. The term heath bald is used in this paper to include all such treeless areas dominated by members of the order Ericales. The use of the term heath is not entirely unsatisfactory, since there is considerable confusion in the literature in respect to the exact meaning of such terms as heath, low moor, high moor, etc., yet no substitute for the word has been found
Two-dimensional electron gas in a modulation-doped SrTiO3/Sr(Ti,Zr)O3 heterostructure
A two-dimensional electron gas (2DEG) in SrTiO3 is created via modulation
doping by interfacing undoped SrTiO3 with a wider-band-gap material,
SrTi1-xZrxO3, that is doped n-type with La. All layers are grown using hybrid
molecular beam epitaxy. Using magnetoresistance measurements, we show that
electrons are transferred into the SrTiO3, and a 2DEG is formed. In particular,
Shubnikov-de Haas oscillations are shown to depend only on the perpendicular
magnetic field. Experimental Shubnikov-de Haas oscillations are compared with
calculations that assume multiple occupied subbands.Comment: Submitted to Applied Physics Letter
A Biological Spectrum of the Flora of the Great Smoky Mountains National Park
The present study of life-forms of the Great Smoky Mountains flora is based on the system of Raunkiaer (1934). Realizing the difficulties involved in correlation of meteorological and climatological data with the natural occurrences of plants, Raunkiaer designed his life-form system as a means of defining what he called phytoclimates. The theoretical basis was a familiar one in plant geography (Cain, 1944) and may be expressed as follows: (1) Plants are limited in their capacity to endure different environmental complexes. (2) There is usually a correlation between the morphology (growth-form, life-form) of an organism and its environment, i.e., there is a morphological basis for adaptation in many if not all cases. (3) A plant, in its successful existence, represents what may be called an automatic physiological integration of all the factors of its environment. It follows, if these are general truths, that the life-forms of the plants of an area are a measure of the environmental conditions, especially climate. It remains only to find the key to the plant-climate interrelations
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