bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of leaf size, leaf habit, and leaf form on leaf/stem relationships in plant twigs of temperate woody species
Authors: Yang Dongmei , Li Guoyong , Sun Shucun 
Published: March 2009

AbstractQuestion: Do thick‐twigged/large‐leaf species have an advantage in leaf display over their counterparts, and what are the effects of leaf habit and leaf form on the leaf‐stem relationship in plant twigs of temperature broadleaf woody species?Location: Gongga Mountain, southwest China.Methods: (1) We investigated stem cross‐sectional area and stem mass, leaf area and leaf/lamina mass of plant twigs (terminal branches of current‐year shoots) of 89 species belonging to 55 genera in 31 families. (2) Data were analyzed to determine leaf‐stem scaling relationships using both the Model type II regression method and the phylogenetically independent comparative (PIC) method.Results: (1) Significant, positive allometric relationships were found between twig cross‐sectional area and total leaf area supported by the twig, and between the cross‐sectional area and individual leaf area, suggesting that species with large leaves and thick twigs could support a disproportionately greater leaf area for a given twig cross‐sectional area. (2) However, the scaling relationships between twig stem mass and total leaf area and between stem mass and total lamina mass were approximately isometric, which indicates that the efficiency of deploying leaf area and lamina mass was independent of leaf size and twig size. The results of PIC were consistent with these correlations. (3) The evergreen species were usually smaller in total leaf area for a given twig stem investment in terms of both cross‐sectional area and stem mass, compared to deciduous species. Leaf mass per area (LMA) was negatively associated with the stem efficiency in deploying leaf area. (4) Compound leaf species could usually support a larger leaf area for a given twig stem mass and were usually larger in both leaf size and twig size than simple leaf species.Conclusions: Generally, thick‐twigged/large‐leaf species do not have an advantage over their counterparts in deploying photosynthetic compartments for a given twig stem investment. Leaf habit and leaf form types can modify leaf‐stem scaling relationships, possibly because of contrasting leaf properties. The leaf size‐twig size spectrum is related to the LMA‐leaf life span dimension of plant life history strategies.
Biting the hand that feeds: the invasive grass Schismus barbatus (Poaceae) is facilitated by, but reduces establishment of, the native shrub Ambrosia dumosa (Asteraceae)
Authors: Rodríguez‐Buriticá Susana , Miriti Maria N. 
Published: March 2009

AbstractQuestion: We present a study of positive and negative interactions between the invasive grass Schismus barbatus (Poaceae) and Ambrosia dumosa (Asteraceae). Ambrosia facilitates seedling establishment, and such facilitation may accelerate invasion of exotic species, which, in turn, may reduce establishment of native plants.Location: Joshua Tree National Park, California, USA.Methods: During 2003‐2004, we used field surveys to characterize the natural spatial distribution of Schismus in relation to native shrubs, and experimentally manipulated seed rain of Ambrosia and Schismus at three distances from adult Ambrosia canopies. We measured percentage germination and individual performance of both species. Field data were complemented by a greenhouse experiment that measured competition between Ambrosia seedlings and Schismus planted at three densities and five relative abundances under controlled conditions.Results: Field surveys showed that the density of Schismus is independent of Ambrosia shrubs, but growth is enhanced near shrub canopies. In our field experiment Schismus is facilitated by adult Ambrosia. Under controlled conditions, Schismus does not respond to the density of Ambrosia seedlings, but changes in density of Schismus decreased performance of Ambrosia seedlings.Conclusion: Schismus invasion may be detrimental to native perennial plant populations. Although a reduction of seedling establishment is not usually expected to slow population growth of long‐lived perennials, recent unprecedented adult mortality in this community, and the well‐documented facilitative role of Ambrosia, suggest that Schismus invasion may be of high ecological significance.
Air humidity, soil moisture and soil chemistry as determinants of the herb layer composition in European beech forests
Authors: Leuschner Christoph , Lendzion Jasmin 
Published: March 2009

AbstractQuestion: What role does air humidity play as an environmental factor for the abundance and distribution of temperate woodland herbs?Location: Beech forests on calcareous soils in southern lower Saxony, central Germany.Methods: The abundance of woodland herb species and total herb cover were investigated in 60 plots with contrasting exposure, slope angle and relief type. On all plots, air humidity, air temperature, soil moisture, photosynthetically active radiation, pH (H2O) and concentration of salt‐exchangeable Ca, Mg and K were measured. Species‐environment relationships were analysed with multiple regression analysis and CCA.Results: Air humidity (RH), soil moisture and the concentration of exchangeable Ca and K, but not light, C/N ratio and the concentration of exchangeable Mg were identified as the most important abiotic factors influencing the cover of the most abundant plant species and total herb cover. RH varied substantially across the different forest floor site types and influenced species abundance independent of soil moisture. In several species (including Mercurialis perennis and Impatiens noli‐tangere), RH was found to be a key environmental factor. Other species such as Aegopodium podagraria and Lamiastrum galeobdolon depended more on elevated soil moisture, while RH was less important.Conclusions: This study showed that the distribution of widespread temperate woodland herb species depends on high air humidity, and that certain sensitive species do not occur at sites with reduced air humidity even though soil moisture is high. Thus, high air humidity and ample soil moisture are key abiotic factors in beech forests on calcareous soils. Shade level (PAR) was found to be of secondary importance.
Discriminating trait‐convergence and trait‐divergence assembly patterns in ecological community gradients
Authors: Pillar Valério D. , Duarte Leandro da S. , Sosinski Enio E. , Joner Fernando 
Published: March 2009

AbstractQuestion: Whereas similar ecological requirements lead to trait‐convergence assembly patterns (TCAP) of species in communities, the interactions controlling how species associate produce trait‐divergence assembly patterns (TDAP). Yet, the linking of the latter to community processes has so far only been suggested. We offer a method to elucidate TCAP and TDAP in ecological community gradients that will help fill this gap.Method: We evaluated the correlation between trait‐based described communities and ecological gradients, and using partial correlation, we separated the fractions reflecting TCAP and TDAP. The required input data matrices describe operational taxonomic units (OTUs) by traits, communities by the quantities or presence‐absence of these OTUs, and community sites by ecological variables. We defined plant functional types (PFTs) or species as community components after fuzzy weighting by the traits. The measured correlations for TCAP and TDAP were tested by permutation. The null model for TDAP preserves the trait convergence, the structure intrinsic in the fuzzy types, and community total abundances and autocorrelation.Results: We applied the method to trait‐based data from plant communities in south Brazil, one set in natural grassland experimental plots under different nitrogen and grazing levels, and another in sapling communities colonizing Araucaria forest patches of increasing size in a forest‐grassland mosaic. In these cases, depending on the traits considered, we found strong evidence of either TCAP or TDAP, or both, that was related to the environmental gradients.Conclusions: The method developed is able to reveal TCAP and TDAP that are more likely to be functional for specified ecological gradients, allowing establishment of objective hypotheses on their links to community processes.
Do changes in rainfall patterns affect semiarid annual plant communities?
Authors: Miranda Juan de Dios , Padilla F.M. , Lázaro R. , Pugnaire F.I. 
Published: March 2009

AbstractQuestion: Climate change models forecast a reduction in annual precipitation and more extreme events (less rainy days and longer drought periods between rainfall events), which may have profound effects on terrestrial ecosystems. Plant growth, population and community dynamics in dry environments are likely to be affected by these changes since productivity is already limited by water availability. We tested the effects of reduced precipitation and fewer rain events on three semiarid plant communities dominated by annual species.Location: Three semiarid plant communities from Almería province (SE Spain).Methods: Rain‐out shelters were set up in each community and watering quantity and frequency were manipulated from autumn to early summer. Plant productivity, cover and diversity were measured at the end of the experimental period.Results: We found that a 50% reduction in watering reduced productivity, plant cover and diversity in all three communities. However, neither the 25% reduction in watering nor changes in the frequency of watering events affected these parameters.Conclusions: The lack of response to small reductions in water could be due to the identity and resistance of the plant communities involved, which are adapted to rainfall variability characteristic of arid environments. Therefore, a rainfall reduction of 25% or less may not affect these plant communities in the short term, although higher reductions or long‐term changes in water availability would probably reduce productivity and diversity in these communities.
Recruitment limitation of forest communities in a degraded Mediterranean landscape
Authors: Mendoza Irene , Gómez‐Aparicio Lorena , Zamora Regino , Matías Luis 
Published: March 2009

AbstractQuestion: How does habitat degradation affect recruitment limitation and its components (seed limitation versus establishment limitation) of woody plant communities in a Mediterranean landscape?Location: 1600‐1900 m a.s.l. in the Sierra Nevada National Park, southern Spain. The landscape is a mosaic composed of native forest and two degraded landscape units: reforestation stands and shrubland.Methods: We evaluated fruit production, seed rain, seedling emergence and seedling survival in two consecutive years with contrasting rainfall patterns. Seed and seedling data were used to calculate values of seed and establishment limitation.Results: In general, the woody community was both severely seed‐ and establishment‐limited. Species were less seed‐limited in the landscape units with higher adult density (i.e. shrub species in shrubland, Pinus spp. in reforestation stands). In contrast, degradation did not exacerbate establishment limitation, which was severe in all landscape units. This general pattern was modulated by the biogeographical distribution, dispersal type, and life form of the species. Boreo‐alpine species were more limited in establishment than species with a typical Mediterranean distribution. Zoochorous species were less seed‐limited in the landscape units preferred by dispersers (i.e. native forest). Tree species were more establishment‐limited than shrub species, irrespective of the landscape unit. Seed limitation, and especially establishment limitation, varied among years, with establishment being almost nil in the very dry year.Conclusion: In the case of Mediterranean landscapes, when degradation from human impact involves a reduction in the adult abundance of the woody plant community (trees and shrubs), seed limitation increases, although establishment limitation is generally high in all landscape units, especially for boreo‐alpine species. Conservation and restoration strategies should take into account our results showing that tree species were unable to recruit in an extremely dry year, because more aridity is expected under a climatic change scenario in Mediterranean ecosystems.
Post‐fire shrub recruitment in a semi‐arid grassland: the role of microsites
Authors: Franzese Jorgelina , Ghermandi Luciana , Donaldo Bran 
Published: March 2009

AbstractQuestion: (1) Which factors regulate post‐fire recruitment and spread of the shrub Senecio bracteolatus in Patagonian grasslands? (2) What is the role of the grass Stipa speciosa on S. bracteolatus establishment in the post‐fire succession?Location: Northwest Patagonia, Argentina.Methods: We studied the effect of fire on S. bracteolatus recruitment and density by comparing these variables between burned and unburned grasslands. In burned areas, we compared abiotic characteristics and seedling establishment under the canopy of grasses (S. speciosa) and in gaps (inter‐tussock areas). Post‐fire interactions between S. bracteolatus seedlings and S. speciosa were studied using field and greenhouse experiments.Results: Density of S. bracteolatus was higher in burned than in unburned areas. In burned sites, seedlings were more abundant under tussock grasses, whereas juveniles were more abundant in gaps. Tussocks generated more attenuated micro‐environmental conditions than gaps during stressful summers. Gaps were more abundant in burned sites, while “under tussock” microsites were more frequent in unburned sites. In burned areas, tussocks allowed higher establishment of seedlings (facilitation), but gaps allowed more seedling growth and higher persistence of juveniles.Conclusions: Fire promoted S. bracteolatus recruitment in Patagonian grasslands by increasing the availability of favourable gap microsites. Grass protection for shrub seedlings became negative with time, probably due to competition with grasses. Gaps led to better performance and persistence of shrub plants. Six years after fire, higher shrub recruitment and adult density (observed as a trend) in burned grassland provides an opportunity for potential S. bracteolatus invasion.
How do trees die? Mode of death in northern Amazonia
Authors: Chao Kuo‐Jung , Phillips Oliver L. , Monteagudo Abel , Torres‐Lezama Armando , Vásquez Martínez Rodolfo 
Published: March 2009

AbstractQuestion: How do trees die in high‐mortality and low‐mortality Amazonian forest regions? Why do trees die in different ways?Location: Humid, lowland forests in Amazonian Peru and Venezuela.Methods: Patterns of multiple treefall and mode of death (standing, broken or uprooted) were recorded for trees ≥10 cm in diameter in permanent plots. Logistic regression was used to relate mode of death to tree diameter, relative growth rate and wood density.Results: Frequency of multiple death events was higher in high‐mortality northwestern (NW) than in low‐mortality northeastern (NE) Amazonia, but these events were small, averaging two trees killed per multiple death event. Breakage was the dominant known mode of death (51±8%) in the NW, with half of fatal breakages caused by other treefalls or breakages. Small and slow‐growing trees were more prone to breaking than uprooting. In NE Amazonia, the dominant known mode of death was standing (48±10%); these trees tended to be relatively large and slow growing. Broken trees in NE forests have a lower wood density than uprooted trees.Conclusions: The major mortality mechanisms differ in the two regions. In the NW it involves an interaction between physiological failure and mechanical failure (small size, slow growth and broken mode). In the NE it is mainly driven by physiological failure (large size, slow growth and standing mode). We propose that by creating different‐sized gaps the different dominant modes of death would favour species from different functional groups and so help to maintain the contrasting functional composition and mortality rates of the two regions.
Building a program of research
Authors: HOLZEMER William L. 
Published: March 2009

AbstractThis article provides highlights of a talk titled, “Building a Program of Research,” given at the Japan Academy of Nursing Science's 28th annual meeting, Fukuoka, Japan, on 13 December 2008. A program of research is defined as a coherent expression of a researcher's area of interest that has public health significance, builds from the published research literature in the field, has relevance for clinical nursing practice, and captures the passion and commitment of the researcher. The Outcomes Model for Health Care Research is proposed as a framework for how to develop and articulate a program of research. Eight steps are proposed to help a new researcher to think about how to build a program of research.
Schizophrenia Modifying the Expression of Gender Identity Disorder
Authors: Baltieri Danilo Antonio , De Andrade Arthur Guerra 
Published: March 2009

ABSTRACT

Introduction
According to the Brazilian Federal Medical Association, transsexualism is recognized as a gender identity disorder if a long-term diagnostic therapeutic process has demonstrated that the transposition of gender roles is irreversible, and if only hormonal and surgical procedures are appropriate to relieve the stress associated with the gender identity. Although such treatment will only be initiated with caution and after a long phase of intense diagnostic screening, the differentiation between pure identity disorders and transsexual feelings secondary to an ongoing psychopathologic process, such as schizophrenia, can be arduous for many health professionals.

Aim
To report a case of a female patient with schizophrenia and transsexualism and the risks of a potential diagnostic confusion.

Method
A 19-year-old black woman, with an 8-year history of undifferentiated schizophrenia and intense gender dysphoria, was referred for sex reassignment surgery evaluation in the Ambulatory for the Treatment of Sexual Disorders of the ABC Medical School.

Result
After a more adequate antipsychotic treatment, her masculine behavior has persisted, but her desire to change her own genital organs has decreased.

Conclusion
A better acceptance of the multiplicity of possible genders should neither contribute to inadequate interpretations of the signs and symptoms of our patients nor facilitate dangerous clinical or surgical recommendations.
The Social Context for Psychological Distress from Iatrogenic Gynecomastia with Suggestions for its Management
Authors: Wassersug Richard J. , Oliffe John L. 
Published: March 2009

ABSTRACT

Introduction
Gynecomastia (breast development in males) is a side effect of androgen deprivation therapy (ADT) for prostate cancer (PCa). Medical interventions to prevent or treat gynecomastia carry risk of additional detrimental side effects. However, untreated gynecomastia can be physically uncomfortable and psychologically distressing. Shame from gynecomastia can lead patients to stop otherwise beneficial exercise.

Aims
Our first aim is to explore the social context for gynecomastia and how it is interpreted by men with the condition, as well as by others, both male and female. Subsequently, we use our understanding of why gynecomastia is psychologically distressing to propose psychosocial interventions that could help men accept this side effect of ADT.

Methods
We draw on academic literature, media accounts, and web-based testimonials from men with gynecomastia, to understand how gynecomastia is perceived by both patients and the medical community. We examine these resources in light of gynecomastia’s impact on sex roles, sexuality, and gender identity issues.

Main Outcome Measures
By exploring what breasts in a male mean to the individual, we produce an understanding of the social context for distress from gynecomastia. From this understanding, we derive hypotheses about who might be most distressed from gynecomastia and strategies for alleviating this distress.

Results
The shame and stigma of gynecomastia is linked to the objectification of women. We suggest that men fear that their breasts will marginalize and subordinate them within gender hierarchies. There is little evidence that breasts on a male erotically attract either men or women. Novel options for living with gynecomastia are contrasted with medicalized strategies including mastectomy.

Conclusion
Assessment instruments need to be developed to identify patients most likely to experience distress from gynecomastia and seek out medical interventions. Surgical, radiological, or pharmacological interventions may not be universally necessary if greater acceptance of gynecomastia is made available through psychosocial support programs. For example, PCa patients may learn to accept gynecomastia through reconceptualizing their breasts as autoerotic. Support programs modeled on those of the breast cancer community, including Encore and dragon boat racing, may also help to build communities to serve patients with gynecomastia while defending individuals against shame, isolation, and loss of self-esteem.
Climate Change Enhances the Potential Impact of Infectious Disease and Harvest on Tropical Waterfowl
Authors: Traill Lochran W. , Bradshaw Corey J. A. , Field Hume E. , Brook Barry W. 
Published: March 2009

ABSTRACTGlobal warming exacerbates threats to biodiversity as ecological systems shift in response to altered climatic conditions. Yet the long‐term survival of populations at direct risk from climate change may also be undermined by local factors such as infectious disease or anthropogenic harvest, which leave smaller and more isolated populations increasingly vulnerable to the rapid pace of global change. We review current and future threats to an exemplar tropical waterfowl species, magpie geeseAnseranas semipalmata, and focus on the potential synergies between infectious diseases, harvest, and climate change. We outline viral, bacterial, and fungal pathogens likely to cause disease in geese, and give mention to parasites. Further, we elaborate on a previously developed, spatially explicit population viability model to simulate demographic responses to hunting and novel or enhanced disease outbreaks due to climate change. With no harvest, the simulated disease epizootics only threatened metapopulation viability when both mortality rate was high and outbreaks were regular (a threshold response). However, when contemporary site‐specific harvest is included as an additive impact, the response to disease severity and probability was linear. We recommend field research to test these hypotheses linking drivers of waterfowl population decline to disease–climate change interactions.