449 research outputs found

    Mass-spectrometric study of the rhenium-oxygen system

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    Rhenium, having the second highest melting point among the metals, is used for refractory containers. Thermodynamic values for rhenium oxide is determined by mass spectrometry and X ray diffraction

    Community and population dynamics of spruce-fir forests on Whiteface Mountain, New York: recent trends, 1985-2000

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    We remeasured two sets of permanent plots in old-growth, spruce–fir forests on Whiteface Mountain to quantify ongoing vegetation dynamics at sites impacted by spruce decline. One set of plots was a stratified random sample of the vegetation in a subalpine watershed (Baldwin site). The other was selected to represent forest conditions in a high-elevation subset of the spruce–fir forest (Esther site). Between 1987 and 1997, there was a significant increase in aboveground tree biomass at Baldwin with the majority of the increment due to the growth of canopy-sized trees. This growth occurred with little change in either species composition or size structure. The annual mortality rate of 1.2%·year–1 for canopy-sized red spruce (Picea rubens Sarg.) in Baldwin almost matched the recruitment rate of 1.4 stems/ha per year. In addition, the relative growth rate of spruce was significantly faster than associated species. In contrast, spruce trees in Esther died at a rate of the 3.6%·year–1 (1985–1995), and survivors grew more slowly than other species. The most obvious community-level trend at Esther (1985–2000) was an increase in overall tree density with most of this increase due to ingrowth of small trees. The demography of the spruce population at Baldwin suggests that the decline is over for at least this population

    Sexual Dimorphisms in Habitat-Specific Morphology and Behavior in the Green Anole Lizard

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    Species that occur in variable environments often exhibit morphological and behavioral traits that are specific to local habitats. Because the ability to move effectively is closely associated with structural habitat, locomotor traits may be particularly sensitive to fine-scale habitat differences. Anolis lizards provide an excellent opportunity to study the relationship between locomotion and natural perch use in the field, as laboratory studies have demonstrated that lizards that use broader perches develop longer limbs and have higher sprint speeds. We examined Anolis carolinensis (the green anole) in three habitats in close proximity. Our goals were to determine whether habitat-specific differences in hindlimb and toe morphologies occurred in a population in which perch size was variable but not manipulated, whether locomotor behaviors were associated with these morphologies, and whether habitat-specific traits differed between the sexes. We found that while juveniles in the three habitats did not differ in limb or toe morphology, adult females using broader perches had relatively longer limbs than females using narrower perches. Females also differed in toe length across habitats, but not in relation to perch diameter. Males, in contrast, exhibited differing growth patterns (allometry) in these traits, and marginal differences in locomotor behavior. Together, these results suggest that sex-specific responses in morphology and behavior, consistent with experimental observations of phenotypic plasticity, provide a mechanism for refining local habitat use

    Sexual Dimorphisms in Habitat-Specific Morphology and Behavior in the Green Anole Lizard

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    Species that occur in variable environments often exhibit morphological and behavioral traits that are specific to local habitats. Because the ability to move effectively is closely associated with structural habitat, locomotor traits may be particularly sensitive to fine-scale habitat differences. Anolis lizards provide an excellent opportunity to study the relationship between locomotion and natural perch use in the field, as laboratory studies have demonstrated that lizards that use broader perches develop longer limbs and have higher sprint speeds. We examined Anolis carolinensis (the green anole) in three habitats in close proximity. Our goals were to determine whether habitat-specific differences in hindlimb and toe morphologies occurred in a population in which perch size was variable but not manipulated, whether locomotor behaviors were associated with these morphologies, and whether habitat-specific traits differed between the sexes. We found that while juveniles in the three habitats did not differ in limb or toe morphology, adult females using broader perches had relatively longer limbs than females using narrower perches. Females also differed in toe length across habitats, but not in relation to perch diameter. Males, in contrast, exhibited differing growth patterns (allometry) in these traits, and marginal differences in locomotor behavior. Together, these results suggest that sex-specific responses in morphology and behavior, consistent with experimental observations of phenotypic plasticity, provide a mechanism for refining local habitat use

    What e-patients want from the doctor-patient relationship: content analysis of posts on discussion boards.

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    People with long-term conditions are encouraged to take control and ownership of managing their condition. Interactions between health care staff and patients become partnerships with sharing of expertise. This has changed the doctor-patient relationship and the division of roles and responsibilities that traditionally existed, but what each party expects from the other may not always be clear. Information that people with long-term conditions share on Internet discussion boards can provide useful insights into their expectations of health care staff. This paper reports on a small study about the expectations that people with a long-term condition (diabetes) have of their doctors using information gleaned from Internet discussion boards

    The promise and peril of intensive-site-based ecological research: insights from the Hubbard Brook ecosystem study

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    Abstract. Ecological research is increasingly concentrated at particular locations or sites. This trend reflects a variety of advantages of intensive, site-based research, but also raises important questions about the nature of such spatially delimited research: how well does site based research represent broader areas, and does it constrain scientific discovery?We provide an overview of these issues with a particular focus on one prominent intensive research site: the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA. Among the key features of intensive sites are: long-term, archived data sets that provide a context for new discoveries and the elucidation of ecological mechanisms; the capacity to constrain inputs and parameters, and to validate models of complex ecological processes; and the intellectual cross-fertilization among disciplines in ecological and environmental sciences. The feasibility of scaling up ecological observations from intensive sites depends upon both the phenomenon of interest and the characteristics of the site. An evaluation of deviation metrics for the HBEF illustrates that, in some respects, including sensitivity and recovery of streams and trees from acid deposition, this site is representative of the Northern Forest region, of which HBEF is a part. However, the mountainous terrain and lack of significant agricultural legacy make the HBEF among the least disturbed sites in the Northern Forest region. Its relatively cool, wet climate contributes to high stream flow compared to other sites. These similarities and differences between the HBEF and the region can profoundly influence ecological patterns and processes and potentially limit the generality of observations at this and other intensive sites. Indeed, the difficulty of scaling up may be greatest for ecological phenomena that are sensitive to historical disturbance and that exhibit the greatest spatiotemporal variation, such as denitrification in soils and the dynamics of bird communities. Our research shows that end member sites for some processes often provide important insights into the behavior of inherently heterogeneous ecological processes. In the current era of rapid environmental and biological change, key ecological responses at intensive sites will reflect both specific local drivers and regional trends

    Exile Vol. XVII No. 2

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    POETRY Grammer lesson by Julie Lockwood 5 Hunter by J. Barmeier 10 (rare) by Alice Merrill 13 November Leaf by J. Barmeier 13 In retrospect by Julie Lockwood 14 Weaving by Alice Merrill 16 SPETSE by Cary Anne Spear 17 View From A Garret To Infinity J. Barmeier 18 Morning after Reflection by J. Barmeier 19 A MINOR CHANGE AT DENISON U.? by Pete Porteous 30 Snowflak by J. Barmeier 32 LOVING by Curtis Hutchens 34 IRISH CONVERSATION by Cary Anne Spear 36 On This Planet by yasue aoki 39 FICTION Visiting Before The Mirror by Holly Battles 8-9, 31 Cypher by Keith McWalter 22-28 ART by Sandy Adams: Cover, 31 by Beth Newman 4 by Jill Harris 6, 13 by Ned Bittinger 7 by Bill Musgrave 12, 20 by Gail Lutsch 15, 18, 26, 29 by M. A. Albert 31 by Charlie Greacen 35 by Diane Ulmer 38 PHOTOGRAPHY by Jill Harris 19 all others by Tim Het
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