3,468 research outputs found
Preliminary Survey of the Terrestrial Isopods (Isopoda), Millipedes (Diplopoda), Harvestmen (Opiliones), and Spiders (Araneae) of Toft Point Natural Area, Door County, Wisconsin
Toft Point Natural Area is a National Natural Landmark owned and managed by the University of Wisconsin – Green Bay and located on the Lake Michigan shore of Wisconsin’s Door Peninsula. With twelve biotic communities on 700 acres, Toft Point contains considerable biological diversity. We conducted a preliminary survey of the arachnids (spiders and harvestmen, excluding mites and pseudoscorpions), millipedes (diplopods), and terrestrial isopods (Isopoda: Oniscoidea).
Sampling occurred on three dates in 2001 using leaf litter collection with Berlese extraction and a timed collection by hand that incorporated a variety of techniques. Specimens from a 1992 survey and assorted collecting events were also used to compile a species list. The list includes five isopods, four millipedes, six harvestmen, and 113 spiders, including 16 new state records (two millipedes and 14 spiders) and 90 new Door County records. Litter collection and sampling in wetland habitats were both especially productive
The carotenoid-continuum: carotenoid-based plumage ranges from conspicuous to cryptic and back again
<p>Abstract</p> <p>Background</p> <p>Carotenoids are frequently used by birds to colour their plumage with green, yellow, orange or red hues, and carotenoid-based colours are considered honest signals of quality, although they may have other functions, such as crypsis. It is usually assumed that red through yellow colours have a signalling function while green is cryptic. Here we challenge this notion using the yellow and green colouration of blue tits (<it>Cyanistes caeruleus</it>), great tits (<it>Parus major</it>) and greenfinches (<it>Carduelis chloris</it>) as a model.</p> <p>Results</p> <p>The relationship between colouration (chroma, computed using visual sensitivities of conspecifics) and detectability (contrast against natural backgrounds as perceived by conspecifics and avian predators) followed a similar curvilinear pattern for yellow and green plumage with minimum detectability at intermediate levels of carotenoid deposition. Thus, for yellow and green plumage, colours at or close to the point of minimum detectability may aid in crypsis. This may be the case for blue and great tit green and yellow plumage, and greenfinch green plumage, all of which had comparably low levels of detectability, while greenfinch yellow plumage was more chromatic and detectable. As yellow and green blue tit colouration are strongly affected by carotenoid availability during moult, variation in pigment availability between habitats may affect the degree of background-matching or the costliness of producing cryptic plumage.</p> <p>Conclusions</p> <p>Increasing carotenoid-deposition in the integument does not always lead to more conspicuous colours. In some cases, such as in blue or great tits, carotenoid deposition may be selected through enhanced background-matching, which in turn suggests that producing cryptic plumage may entail costs. We stress however, that our data do not rule out a signalling function of carotenoid-based plumage in tits. Rather, it shows that alternative functions are plausible and that assuming a signalling function based solely on the deposition of carotenoids in the integument may not be warranted.</p
Magnetic interaction of Co ions near the {10\bar{1}0} ZnO surface
Co-doped ZnO is the prototypical dilute magnetic oxide showing many of the
characteristics of ferromagnetism. The microscopic origin of the long range
order however remains elusive, since the conventional mechanisms for the
magnetic interaction, such as super-exchange and double exchange, fail either
at the fundamental or at a quantitative level. Intriguingly, there is a growing
evidence that defects both in point-like or extended form play a fundamental
role in driving the magnetic order. Here we explore one of such possibilities
by performing {\it ab initio} density functional theory calculations for the
magnetic interaction of Co ions at or near a ZnO \{100\} surface. We
find that extended surface states can hybridize with the -levels of Co and
efficiently mediate the magnetic order, although such a mechanism is effective
only for ions placed in the first few atomic planes near the surface. We also
find that the magnetic anisotropy changes at the surface from an hard-axis
easy-plane to an easy axis, with an associated increase of its magnitude. We
then conclude that clusters with high densities of surfacial Co ions may
display blocking temperatures much higher than in the bulk
Smooth tail index estimation
Both parametric distribution functions appearing in extreme value theory -
the generalized extreme value distribution and the generalized Pareto
distribution - have log-concave densities if the extreme value index gamma is
in [-1,0]. Replacing the order statistics in tail index estimators by their
corresponding quantiles from the distribution function that is based on the
estimated log-concave density leads to novel smooth quantile and tail index
estimators. These new estimators aim at estimating the tail index especially in
small samples. Acting as a smoother of the empirical distribution function, the
log-concave distribution function estimator reduces estimation variability to a
much greater extent than it introduces bias. As a consequence, Monte Carlo
simulations demonstrate that the smoothed version of the estimators are well
superior to their non-smoothed counterparts, in terms of mean squared error.Comment: 17 pages, 5 figures. Slightly changed Pickand's estimator, added some
more introduction and discussio
Exact ground state of finite Bose-Einstein condensates on a ring
The exact ground state of the many-body Schr\"odinger equation for bosons
on a one-dimensional ring interacting via pairwise -function
interaction is presented for up to fifty particles. The solutions are obtained
by solving Lieb and Liniger's system of coupled transcendental equations for
finite . The ground state energies for repulsive and attractive interaction
are shown to be smoothly connected at the point of zero interaction strength,
implying that the \emph{Bethe-ansatz} can be used also for attractive
interaction for all cases studied. For repulsive interaction the exact energies
are compared to (i) Lieb and Liniger's thermodynamic limit solution and (ii)
the Tonks-Girardeau gas limit. It is found that the energy of the thermodynamic
limit solution can differ substantially from that of the exact solution for
finite when the interaction is weak or when is small. A simple relation
between the Tonks-Girardeau gas limit and the solution for finite interaction
strength is revealed. For attractive interaction we find that the true ground
state energy is given to a good approximation by the energy of the system of
attractive bosons on an infinite line, provided the interaction is stronger
than the critical interaction strength of mean-field theory.Comment: 28 pages, 11 figure
Preliminary Survey of the Terrestrial Isopods (Isopoda), Millipedes (Diplopoda), Harvestmen (Opiliones), and Spiders (Araneae) of Toft Point Natural Area, Door County, Wisconsin
Toft Point Natural Area is a National Natural Landmark owned and managed by the University of Wisconsin – Green Bay and located on the Lake Michigan shore of Wisconsin’s Door Peninsula. With twelve biotic communities on 700 acres, Toft Point contains considerable biological diversity. We conducted a preliminary survey of the arachnids (spiders and harvestmen, excluding mites and pseudoscorpions), millipedes (diplopods), and terrestrial isopods (Isopoda: Oniscoidea).
Sampling occurred on three dates in 2001 using leaf litter collection with Berlese extraction and a timed collection by hand that incorporated a variety of techniques. Specimens from a 1992 survey and assorted collecting events were also used to compile a species list. The list includes five isopods, four millipedes, six harvestmen, and 113 spiders, including 16 new state records (two millipedes and 14 spiders) and 90 new Door County records. Litter collection and sampling in wetland habitats were both especially productive
Spiders of the UW-Milwaukee Field Station
A checklist of 100 species from 16 families is presented in this preliminary report of spiders at the UWM Field Station. Listed with the species are the months and habitats in which they were collected
Intergenerational transmission of height in a historical population: from taller mothers to larger offspring at birth (and as adults)
Background
Changes in growth and height reflect changes in nutritional status and health. The systematic surveillance of growth can suggest areas for interventions. Moreover, phenotypic variation has a strong intergenerational component. There is a lack of historical family data that can be used to track the transmission of height over subsequent generations. Maternal height is a proxy for conditions experienced by one generation that relates to the health/growth of future generations. Cross-sectional/cohort studies have shown that shorter maternal height is closely associated with lower birthweight of offspring.
Objective/Methods
We analyzed the maternal height and offspring weight at birth in the maternity hospital in Basel, Switzerland, from 1896–1939 (N=ca. 12,000) using GAMs.
Results
We observed that average height of the mothers increased by ca. 4 cm across 60 birth years, and that average birthweight of their children shows a similarly shaped and upward trend 28 years later. Our final model (adjusted for year, parity, sex of the child, gestational age, and maternal birthyear) revealed a significant and almost linear association between maternal height and birthweight. Maternal height was the second most important variable modeling birthweight, after gestational age. In addition, we found a significant association between maternal height and aggregated average height of males from the same birth years at time of conscription, 19 years later.
Conclusions
Our results have implications for public health: When (female/maternal) height increases due to improved nutritional status, size at birth—and subsequently also the height in adulthood of the next generation—increases as well. However, the directions of development in this regard may currently differ depending on the world region
Pachyonychia congenita cornered: report on the 11th A nnual I nternational P achyonychia C ongenita C onsortium Meeting
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109650/1/bjd13341.pd
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