bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of the Gross Motor Function Measure for Use in Children and Adolescents With Traumatic Brain Injuries
Authors: Linder-Lucht Michaela , Othmer Verena , Walther Michael , Vry Julia , Michaelis Ulla , Stein Sabine , Weissenmayer Heike , Korinthenberg Rudolf , Mall Volker ,   and the Gross Motor Function Measure-Traumatic Brain Injury Study Group
Published: October 2007

OBJECTIVES. Motor function recovery is a key goal during rehabilitation of children and adolescents with traumatic brain injury. To evaluate how well treatment strategies improve motor function, we need validated outcome measures that are responsive to change in pediatric patients with traumatic brain injury. The Gross Motor Function Measure has demonstrated excellent psychometric properties in children with cerebral palsy and Down syndrome, yet its responsiveness in patients with pediatric traumatic brain injury has not been proven irrefutably. Our aim was to validate the Gross Motor Function Measure for this patient group.

METHODS. Seventy-three patients (mean age: 11.4 years; range: 0.8–18.9 years) with moderate-to-severe traumatic brain injury were recruited in 12 rehabilitation centers and assessed twice with the Gross Motor Function Measure-88 over 4 to 6 weeks. As an external standard, we used judgements of change made independently by parents, physiotherapists, and 2 video assessors who were not familiar with the patients. We formulated and statistically investigated a priori hypotheses of how Gross Motor Function Measure change scores would correlate with those judgements of change. Both Gross Motor Function Measure versions, the original Gross Motor Function Measure-88 and the more recently developed Gross Motor Function Measure-66, were evaluated.

RESULTS. Both Gross Motor Function Measure change scores correlated significantly with all of the clinical judgements of change. The degree of correlation that we postulated, that the Gross Motor Function Measure change score would correlate highest with the video rating followed by physiotherapists and parents, was fully confirmed by the Gross Motor Function Measure-88 and largely confirmed by the Gross Motor Function Measure-66. Both Gross Motor Function Measure versions revealed convincing discriminative capability. Test-retest reliability was excellent.

CONCLUSIONS. We demonstrate convincing evidence of responsiveness and validity to support the use of both Gross Motor Function Measure versions as evaluative measures of gross motor function in children and adolescents with traumatic brain injury.
Family Breakup and Adolescents' Psychosocial Maladjustment: Public Health Implications of Family Disruptions
Authors: Roustit Christelle , Chaix Basile , Chauvin Pierre
Published: October 2007

OBJECTIVES. Recent changes in family structure are associated with an increase in psychosocial maladjustment in adolescents. We examined, from a public health intervention perspective, the association between family breakup and psychosocial maladjustment in adolescents and assessed the mediating role of family-functioning variables.

METHODS. We analyzed data from the Social and Health Survey of Children and Adolescents in Quebec, Montreal, Canada, which was conducted in 1999. Sample-weighted logistic regression analyses were performed to determine the risk of internalizing disorders, externalizing disorders, substance abuse, and alcohol consumption in relation to family breakups and family-functioning variables, after adjusting for socioeconomic factors.

RESULTS. All 4 of the indicators of psychosocial maladjustment were significantly associated with family breakup. The association between family breakups and internalizing disorders was mediated by parental psychological distress and low paternal emotional support. Independently, the witnessing of interparental violence was also strongly associated with internalizing disorders. For the other 3 outcomes, that is, externalizing disorders, substance abuse, and alcohol consumption, family breakup and family-functioning variables had independent effects.

CONCLUSIONS. Family-based interventions and social approaches are complementary support modalities for adolescents experiencing family disruptions.
Influence of Gender and Age on Upper-Airway Length During Development
Authors: Ronen Ohad , Malhotra Atul , Pillar Giora
Published: October 2007

OBJECTIVE. Obstructive sleep apnea has a strong male predominance in adults but not in children. The collapsible portion of the upper airway is longer in adult men than in women (a property that may increase vulnerability to collapse during sleep). We sought to test the hypothesis that in prepubertal children, pharyngeal airway length is equal between genders, but after puberty boys have a longer upper airway than girls, thus potentially contributing to this change in apnea propensity.

METHODS. Sixty-nine healthy boys and girls who had undergone computed tomography scans of their neck for other reasons were selected from the computed tomography archives of Rambam and Carmel hospitals. The airway length was measured in the midsagittal plane and defined as the length between the lower part of the posterior hard palate and the upper limit of the hyoid bone. Airway length and normalized airway length/body height were compared between the genders in prepubertal (4- to 10-year-old) and postpubertal (14- to 19-year-old) children.

RESULTS. In prepubertal children, airway length was similar between boys and girls (43.2 ± 5.9 vs 46.8 ± 7.7 mm, respectively). When normalized to body height, airway length/body height was significantly shorter in prepubertal boys than in girls (0.35 ± 0.03 vs 0.38 ± 0.04 mm/cm). In contrast, postpubertal boys had longer upper airways (66.5 ± 9.2 vs 52.2 ± 7.0 mm) and normalized airway length/body height (0.38 ± 0.05 vs 0.33 ± 0.05 mm/cm) than girls.

CONCLUSIONS. Although boys have equal or shorter airway length compared with girls among prepubertal children, after puberty, airway length and airway length normalized for body height are significantly greater in boys than in girls. These data suggest that important anatomic changes at puberty occur in a gender-specific manner, which may be important in explaining the male predisposition to pharyngeal collapse in adults.
Validity of Parental Report of Influenza Vaccination in Children 6 to 59 Months of Age
Authors: Shinall Myrick C. , Plosa Erin J. , Poehling Katherine A.
Published: October 2007

OBJECTIVE. The objective of this study was to assess the validity of parental report of influenza vaccinations.

PATIENTS AND METHODS. A cross-sectional study of children who were 6 to 59 months of age and presented to a large, pediatric residency clinic from February through April 2005 was performed. A standardized, parental questionnaire ascertained the influenza vaccination status of children during the 2004–2005 influenza season and was compared with the medical chart, the criterion standard. Children were classified as being at high risk when they had a specific influenza vaccine recommendation in 2004–2005 by age (6–23 months of age) or by chronic medical condition.

RESULTS. Of 218 parents approached in the pediatric residency clinic, 198 (95%) children who were 6 to 59 months of age were enrolled, and 84 (42%) were vaccinated according to the medical chart. More children who were 6 to 23 months than those who were 24 to 59 months of age were vaccinated (63% vs 21%). Children with chronic medical conditions were more likely to be vaccinated than healthy children who were 24 to 59 months of age (57% vs 11%), but no difference was observed for children who were 6 to 23 months of age (79% vs 60%). In comparison with the medical chart, parental report of influenza vaccination had a sensitivity of 88%, a specificity of 90%, and a κ coefficient of 0.78. For children who were 6 to 23 months of age or had a chronic medical condition (n = 123), parental report had a sensitivity of 89%, a specificity of 81%, and a κ coefficient of 0.71.

CONCLUSIONS. Parental report of influenza vaccination among children who were 6 to 59 months of age had reasonable sensitivity, specificity, and reliability as compared with the medical chart in this study population.
Synthesis and characterization of 1,2,3,4 tetrahydroquinoline intercalated into MoS2 in search of cleaner fuels
Authors: Castillo Karina , Manciu Felicia , Parsons J.G. , Chianelli Russell R.
Published: October 2007

Two different morphologies of MoS2 (short and long sheets) were utilized to elucidate the intercalation mechanism of 1,2,3,4 tetrahydroquinoline (THQ). MoS2 (short sheets) and molybdenite (MB) (long sheets) were exfoliated and restacked in the presence of THQ. The x-ray diffraction patterns of both samples show a new reflection in the 001 plane, which implies a lowering of symmetry and corresponds to an expansion of the layers by approximately 12.3 Å. In the MoS2-THQ sample, 80% of the MoS2 was intercalated and 20% remained stacked. In the MB-THQ sample, 30% of MB was intercalated while 70% remained stacked. X-ray absorption structure (XAS) studies showed changes in atomic geometry and coordination. The x-ray absorption near-edge spectra showed shifts in the geometry of the intercalated MoS2 and MB sample compared to the unintercalated samples. Extended x-ray absorption fine structure studies showed lower coordination numbers compared to the untreated samples. Infrared spectroscopy characterization of these same samples suggests intercalation and partial dehydrogenation of the THQ.
Thermal stability, microstructure, and electrical properties of atomic layer deposited Hf6Ta2O17gate dielectrics
Authors: Triyoso D.H. , Yu Z. , Gregory R. , Moore K. , Fejes P. , Schauer S.
Published: October 2007

The intent of this work is to investigate thermal stability, microstructure, and electrical properties of thin Hf6Ta2O17high-k gate dielectrics. X-ray diffraction and transmission electron microscopy analysis reveal that an as-deposited Hf6Ta2O17film is amorphous with a ∼1-nm interfacial layer. After a 1000 °C anneal, the film is a mixture of orthorhombic-Hf6Ta2O17and monoclinic HfO2with a thicker interfacial layer. Uniform Hf and Ta Auger depth profiles are observed for as deposited and annealed films. Secondary ion mass spectrometry (SIMS) analysis shows Hf and Ta profiles are unchanged following the 1000 °C anneal, indicating good thermal stability. There is, however, a clear indication of Si up-diffusion into Hf6Ta2O17, particularly after annealing at 1000 °C. No Hf or Ta is found in the Si substrate. Well-behaved capacitance-voltage curves and low leakage current characteristics were obtained for Mo/ Hf6Ta2O17capacitors for as-deposited and 1000 °C annealed films. A flatband voltage (Vfb) shift towards negative voltage is observed for the annealed film when compared to the as-deposited film, indicating the presence of more positive charge, or less negative charge. Furthermore, capacitance-voltage stress measurements were performed to study charge trapping behaviors. A smaller Vfbshift is observed for as deposited (<10 mV) versus the 1000 °C annealed (30-40 mV) Hf6Ta2O17, indicating more charge trapping after the high temperature anneal.
Dissolution and interfacial reactions of Fe in molten Sn-Cu and Sn-Pb solders
Authors: Huang Yu-chih , Chen Sinn-wen , Gierlotka Wojcieh , Chang Chia-hua , Wu Jen-chin
Published: October 2007

Solder pots used in wave soldering are usually made using different kinds of steel. Dissolution and interfacial reactions of the Fe substrate in molten Sn-Pb and Sn-Cu solders are investigated in this study. FeSn2 phase is formed in the Sn-0.7wt%Cu/Fe couples reacted at 250, 400, and 500 °C, as well as in the Sn-37wt%Pb/Fe couples reacted at 250 and 400 °C. The activation energies of formation are 123 and 121 kJ/mol in the Sn-Cu/Fe and Sn-Pb/Fe couples, respectively. FeSn phase is the reaction product in the Sn-37wt%Pb/Fe couples reacted 500 °C. The dissolution rates of Fe in the Sn-0.7wt%Cu melt are much higher than those in-the Sn-37wt%Pb melt. The FeSn2 phase layer in the Sn-Cu/Fe couple is not as dense as that in the Sn-Pb/Fe couple and accounts for the very different dissolution rates. Detachment of the reaction FeSn2 phase into the solder matrix is observed in the Sn-Cu/Fe couples, and is a potential contaminant source in wave soldering.
Achieve p-type conduction in N-doped and (Al,N)-codoped ZnO thin films by oxidative annealing zinc nitride precursors
Authors: Liu Z.W. , Yeo S.W. , Ong C.K.
Published: October 2007

N-doped and (Al,N)-codoped ZnO films were synthesized by oxidative annealing of (Zn + Zn3N2) films, which were fabricated by reactive magnetron sputtering. Both n- and p-type conductions were obtained in these ZnO:N and ZnO:AlN films. Optimal oxidation treatments for achieving p-type ZnO are annealing at 400–600 °C for 10–60 min, depending on the film thickness and morphology. The electric properties were found to be very sensitive to the annealing conditions and film structure. As-deposited (Zn + Zn3N2) films with and without Al addition had carrier concentrations of 1021–1022 cm−3. After conversion to ZnO, the n-type films had a carrier concentrations up to 1019 cm−3, whereas the p-type ZnO:N films had hole concentrations of 1014–1016 cm−3. (Al,N)-codoping increased the hole concentration of p-type film to 1018 cm−3 despite a decrease in Hall mobility. The photoluminescence properties of the p-type ZnO films were also investigated. The synthesis of p-type ZnO:AlN by oxidative annealing is believed to provide an alternative approach to realize p-type conduction in codoped ZnO film by using N2 as the N source.
Genres in Motion
Authors: Owen Stephen
Published: October 2007

When we interrogate a concept like genre, there are advantages to beginning with the way we use the word in the common language. In reading a text, we “identify” or “recognize” a genre. If we attempt to define or describe a genre as such, we are engaging in an entirely different order of activity, one remarkably close to legislation or border control. To identify something assumes a paradigm with a limited set of choices. We may identify a given text differently as a “novel,” a “realist novel,” a “pastoral”; we may debate whether a work is a “novel” or a “prose romance”; but in each case we presume sets of categories on various levels of specificity, whether we deploy particular categories to confirm or surprise common expectations in our identification.
Taskography: Translation as Genre of Literary Labor
Authors: Apter Emily
Published: October 2007

Wai Chee Dimock's chapter on genre as world system, in her recently published bookThrough Other Continents: American Literature across Deep Time,performs a thoroughgoing interrogation of paradigms of periodization and planetary comparatism: “What would literary history look like,” Dimock asks, Her book answers these questions by applying fractal modeling to the scaling of literary chronotypes and geopolitical territories. Dimock uses Benoit Mandelbrot's concept of indeterminate lengths to imagine a literary field of serried shapes, lacy ground, pocked sponges, coiled twine, clumped shapes, cystlike protuberances, and warped intervals (84). “Such irregularities are not limited to just one scale,” Dimock specifies; “they are much more transitive, and much more robustly self-propagating. They carry over tenaciously from one metric to another, spewing out countless copies of themselves on countless dimensions” (77). Dimock's concept of fractals as a self-duplication of literary forms produced in manifold sizes and temporal dimensions and endowed with entropic powers of extension allows her to plot feedback loops between the “gnarled contours of the globe [and] the gnarled contours of every single node” (78). Despite her concern that theorizing genre as a world system delivers “the large literary canvas” at the expense of the text, Dimock insists that such “scalar recursiveness” can in fact “thicken comparative morphology,” diversifying the conceptual grounds of comparison (79).
Remapping Genre through Performance: From “American” to “Hemispheric” Studies
Authors: Taylor Diana
Published: October 2007

Performance as a genre allows for alternative mappings, providing a set of strategies and conventions that allow scholars to see practices that scripted genres might occlude. Like other genres, performance encompasses a broad range of rehearsed and codified behaviors, such as dance, theater, music recitals, sports events, and rituals. A performance lens allows scholars to look at acts, things, and ideas as performance. Looking at America as performance might explain why it is difficult to approach it as a disciplinary field of study. What might the shift in genres—from the scripted genres associated with thearchiveto the live, embodied behaviors that are therepertoireof cultural practices—enable? This essay proposes that an analysis of the performance of America might allow scholars to rethink not only their object of analysis but also their scholarly interactions.
Riding Off into the Sunrise: Genre Contingency and the Origin of the Chinese Western
Authors: Fried Daniel
Published: October 2007

The paradoxical dependence of genre histories on historically accidental acts of naming and on transcendental critical imagination is demonstrated by the Chinese western, a little-understood genre that has become a major part of Chineselanguage cinema over the past two decades. After the genre was proposed in 1984 by the Chinese film theorist Zhong Dianfei, as a realist reaction against the ideological excesses of the Cultural Revolution, its ambiguous status as a Hollywood import quickly became a proxy for larger cultural battles over China's place in an American-dominated international cultural system. Moreover, despite assurances by Zhong and other critics that the genre was not susceptible to Hollywood influence, the production history of the genre from the late 1980s to the present demonstrates a pattern of generic influence and eventual fusion that tracks Chinese state-owned studios' evolution from subsidized propaganda organs to participants in a globalized entertainment industry.
Epistemes and Imitations: Thom Gunn on Ben Jonson
Authors: Hawlin Stefan
Published: October 2007

The mode ofimitatioenhances the persistence and evolution of genres over time, contrary to the implications of Foucault's concept of epistemes (the idea of discontinuous historical eras).Imitatio,well practiced, awakens extraordinary commonalities of sensibility among poets of different periods (classical, Renaissance, contemporary), including how they understand and manipulate genres, and so raises the possibility of a more unitive view of history, culture, and time. Ben Jonson, with his coherent theoretical view ofimitatio,was a crucial poet for Thom Gunn, who self-consciously imitated the mode of imitation, producing in “An Invitation” a re-creation of the country-house poem as embodied by Jonson's “To Sir Robert Wroth” and in “Lament” (his great AIDS elegy) a response to seventeenth-century funeral elegy, in particular Jonson's “Elegie on the Lady Jane Pawlet.”
The AMP-activated protein kinase activator, 5-aminoimidazole-4-carboxamide-1-b-d-ribonucleoside, regulates lactate production in rat Sertoli cells
Authors: Galardo María Noel , Riera María Fernanda , Pellizzari Eliana Herminia , Cigorraga Selva Beatriz , Meroni Silvina Beatriz
Published: October 2007

The aim of the present study was to investigate whether the AMP-activated protein kinase (AMPK), a key regulator of cellular energy homeostasis, is present in Sertoli cells and whether its activation by 5-aminoimidazole-4-carboxamide-1-b-d-ribonucleoside (AICAR) results in the regulation of cell metabolism to ensure lactate supply for germ cell development. Sertoli cell cultures from 20-day-old rats were used. Western blot analysis for the α-subunit of AMPK showed that high levels of AMPK are present in Sertoli cells. Treatment of the cultures with AICAR resulted in a dose- and time-dependent increase of P-AMPK levels indicating activation of the enzyme. A possible effect of AICAR on Sertoli cell lactate production was then analyzed. A dose- and time-dependent increment in lactate secretion was observed. The participation of AMPK activation in different biochemical processes that may be implicated in the regulation of lactate production was also analyzed. AICAR stimulated glucose uptake in a dose- and time-dependent manner. Additionally, AICAR increased the glucose transporter 1 (GLUT1) and decreased the glucose transporter 3 (GLUT3) mRNA levels. As for the role of AMPK in the regulation of the monocarboxylate transporters 1 and 4 (MCT1 and MCT4), it has been observed that AICAR treatment decreased MCT1 and increased MCT4 mRNA levels. In summary, the results presented herein show that AMPK is present in Sertoli cells and that its activation by AICAR increases lactate production as a result, at least in part, of a) an increase in glucose uptake, b) an increase in GLUT1 expression, and c) a decrease in MCT1 and an increase in MCT4 levels. Altogether, these results suggest an important role of AMPK in modulating the nutritional function of Sertoli cells.
G-protein-coupled receptors in aldosterone-producing adenomas: a potential cause of hyperaldosteronism
Authors: Ye Ping , Mariniello Barbara , Mantero Franco , Shibata Hirotaka , Rainey William E
Published: October 2007

The source of aldosterone in 30–40% of patients with primary hyperaldosteronism (PA) is unilateral aldosterone-producing adenoma (APA). The mechanisms causing elevated aldosterone production in APA are unknown. Herein, we examined the expression of G-protein-coupled receptors (GPCRs) in APA and demonstrated that when compared with normal adrenals, there is a general elevation of certain GPCR in many APA and/or ectopic expression of GPCR in others. RNA samples from normal adrenals (n = 5), APAs (n = 10), and cortisol-producing adenomas (CPAs; n = 13) were used on 15 genomic expression arrays, each of which included 223 GPCR transcripts presented in at least 1 out of 15 of the independent microarrays. The array results were confirmed using real-time RT-PCR (qPCR). Four GPCR transcripts exhibited a statistically significant increase that was greater than threefold when compared with normal adrenals, suggesting a general increase in expression when compared with normal adrenal glands. Four GPCR transcripts exhibited a > 15-fold increase of expression in one or more of the APA samples when compared with normal adrenals. qPCR analysis confirmed array data and found the receptors with the highest fold increase in APA expression to be LH receptor, serotonin receptor 4, GnRH receptor, glutamate receptor metabotropic 3, endothelin receptor type B-like protein, and ACTH receptor. There are also sporadic increased expressions of these genes in the CPAs. Together, these findings suggest a potential role of altered GPCR expression in many cases of PA and provide candidate GPCR for further study.
Hydrogen sulphide reduces insulin secretion from HIT-T15 cells by a KATP channel-dependent pathway
Authors: Ali Muhammed Yusuf , Whiteman Matthew , Low Chian-Ming , Moore Philip K
Published: October 2007

Hydrogen sulphide (H2S), a naturally occurring gas exerts physiological effects by opening KATP channels. Anti-diabetic drugs (e.g. glibenclamide) block KATP channels and abrogate H2S-mediated physiological responses which suggest that H2S may also regulate insulin secretion by pancreatic β-cells. To investigate this hypothesis, insulin-secreting (HIT-T15) cells were exposed to NaHS (100 μM) and the KATP channel-driven pathway of insulin secretion was tracked with various fluorescent probes. The concentration of insulin released from HIT-T15 cells decreased significantly after NaHS exposure and this effect was reversed by the addition of glibenclamide (10 μM). Cell viability and intracellular ATP and glutathione (GSH) levels remained unchanged, suggesting that changes in insulin secretion were not ATP linked or redox dependent. Through fluorescence imaging studies, it was found that K+ efflux occurs in cells exposed to NaHS. The hyperpolarised cell membrane, a result of K+ leaving the cell, prevents the opening of voltage-gated Ca2+ channels. This subsequently prevents Ca2+ influx and the release of insulin from HIT-T15 cells. This data suggest that H2S reduces insulin secretion by a KATP channel-dependent pathway in HIT-T15 cells. This study reports the molecular mechanism by which H2S reduces insulin secretion and provides further insight into a recent observation of increased pancreatic H2S production in streptozotocin-diabetic rats.
Refurbishment of London Underground bridge D141
Authors: Bessant G. T. , Williams P.
Published: October 2007

Bridge D141 carries the District line of London Underground over the River Lea and Bow Creek in the east of London in the Greater London area. The District line is one of the three west-to-east lines of the London Underground, the others being the Central line and the Jubilee line. As such, it is of major economic importance. The bridge was built in 1888, and is of relatively light construction compared with modern bridges. The track form was of short longitudinal timbers, and corrosion had reduced the live load capacity. The light form, coupled with the short timbers, gave constant track and ride problems. As the bridge spanned two waterways, maintenance was difficult, and major works became necessary to avoid restrictions. The site being ‘landlocked’ hampered refurbishment works, and closure was not an option, as to do so would have caused unacceptable economic effects. This paper covers the history of the bridge, the problems that developed in the bridge, the solutions to the problems—both structural and in the track form—the refurbishment and strengthening of the bridge, and the problems encountered in the work.
Partnering to improve public transport in developing countries
Authors: Sohail M. , Maunder D. A. C.
Published: October 2007

This paper demonstrates the importance of—and potential for—partnerships between the private and public sectors, and citizen groups, as a crucial means towards the improvement of public transport services in the developing world. It draws mainly upon the research findings of case studies in Karachi, Faisalabad, Dar es Salaam and Colombo between 1999 and 2003. The paper looks at some of the factors that need to be taken into consideration if a partnership is to be successful, before demonstrating the potential of existing links between users, operators and regulators. The potential for partnerships to improve upon the existing situation emerged on several occasions during the research, and these are summarised. Later sections look at the types of partnership that might be encouraged in the transport sector, as well as the importance of nurturing and supporting such partnerships. Finally, the paper highlights priorities for intervention—in the areas of infrastructure investment, land use and employment strategy, regulation and stakeholder collaboration—and the role partnerships could play in these interventions. The paper concludes with the importance of strengthening existing partnerships in public transport provision and creating and developing new ones. In this respect the authors consider it crucial that policymakers give due consideration to partnering approaches in the future.
COMPENSATION AND THE STABILITY OF RESTORED GRASSLAND COMMUNITIES
Authors: Seabloom Eric W.
Published: October 2007

The relationship between community diversity and the stability of summed community biomass has been an area of great theoretical and empirical interest in basic ecology. In general, it has been found that the complementary/compensatory dynamics among species that comprise a community can stabilize aggregate measures of community biomass. Although the potential importance of diversity–stability relationships to restoration ecology has been recognized, to date there has been no quantification of the role these relationships play in increasing the persistence of restored communities in the face of altered disturbance regimes, climatic variability, and over the course of succession. In a large‐scale experimental restoration of a California grassland community, aggregated abundance of restored grasses was more stable than were the individual species in response to disturbance, drought, and succession. Compensatory dynamics among the restored grass flora increased aggregate stability in response to natural and anthropogenic disturbances. Successful restorations must persist in the face of altered management and disturbance regimes, climactic variability, and over the course of succession. Incorporation of diversity–stability relationships into restoration plans will likely increase restoration success. This case study further demonstrates the relevance of community ecology theory to restoration ecology.
TREE GROWTH INFERENCE AND PREDICTION FROM DIAMETER CENSUSES AND RING WIDTHS
Authors: Clark James S. , Wolosin Michael , Dietze Michael , IbáÑez Inés , LaDeau Shannon , Welsh Miranda , Kloeppel Brian
Published: October 2007

Estimation of tree growth is based on sparse observations of tree diameter, ring widths, or increments read from a dendrometer. From annual measurements on a few trees (e.g., increment cores) or sporadic measurements from many trees (e.g., diameter censuses on mapped plots), relationships with resources, tree size, and climate are extrapolated to whole stands. There has been no way to formally integrate different types of data and problems of estimation that result from (1) multiple sources of observation error, which frequently result in impossible estimates of negative growth, (2) the fact that data are typically sparse (a few trees or a few years), whereas inference is needed broadly (many trees over many years), (3) the fact that some unknown fraction of the variance is shared across the population, and (4) the fact that growth rates of trees within competing stands are not independent. We develop a hierarchical Bayes state space model for tree growth that addresses all of these challenges, allowing for formal inference that is consistent with the available data and the assumption that growth is nonnegative. Prediction follows directly, incorporating the full uncertainty from inference with scenarios for “filling the gaps” for past growth rates and for future conditions affecting growth. An example involving multiple species and multiple stands with tree‐ring data and up to 14 years of tree census data illustrates how different levels of information at the tree and stand level contribute to inference and prediction.
ASSOCIATIONS OF FOREST BIRD SPECIES RICHNESS WITH HOUSING AND LANDSCAPE PATTERNS ACROSS THE USA
Authors: Pidgeon A. M. , Radeloff V. C. , Flather C. H. , Lepczyk C. A. , Clayton M. K. , Hawbaker T. J. , Hammer R. B.
Published: October 2007

In the United States, housing density has substantially increased in and adjacent to forests. Our goal in this study was to identify how housing density and human populations are associated with avian diversity. We compared these associations to those between landscape pattern and avian diversity, and we examined how these associations vary across the conterminous forested United States. Using data from the North American Breeding Bird Survey, the U.S. Census, and the National Land Cover Database, we focused on forest and woodland bird communities and conducted our analysis at multiple levels of model specificity, first using a coarse‐thematic resolution (basic models), then using a larger number of fine‐thematic resolution variables (refined models). We found that housing development was associated with forest bird species richness in all forested ecoregions of the conterminous United States. However, there were important differences among ecoregions. In the basic models, housing density accounted for <5% of variance in avian species richness. In refined models, 85% of models included housing density and/or residential land cover as significant variables. The strongest guild response was demonstrated in the Adirondack–New England ecoregion, where 29% of variation in richness of the permanent resident guild was associated with housing density. Model improvements due to regional stratification were most pronounced for cavity nesters and short‐distance migrants, suggesting that these guilds may be especially sensitive to regional processes. The varying patterns of association between avian richness and attributes associated with landscape structure suggested that landscape context was an important mediating factor affecting how biodiversity responds to landscape changes. Our analysis suggested that simple, broadly applicable, land use recommendations cannot be derived from our results. Rather, anticipating future avian response to land use intensification (or reversion to native vegetation) has to be conditioned on the current landscape context and the species group of interest. Our results show that housing density and residential land cover were significant predictors of forest bird species richness, and their prediction strengths are likely to increase as development continues.
CLIMATIC/EDAPHIC CONTROLS ON SOIL CARBON/NITROGEN RESPONSE TO SHRUB ENCROACHMENT IN DESERT GRASSLAND
Authors: Wheeler C. Winston , Archer Steven R. , Asner Gregory P. , McMurtry Chad R.
Published: October 2007

The proliferation of woody plants in grasslands over the past 100+ years can alter carbon, nitrogen, and water cycles and influence land surface–atmosphere interactions. Although the majority of organic carbon in these ecosystems resides belowground, there is no consensus on how this change in land cover has affected soil organic carbon (SOC) and total nitrogen (TN) pools. The degree to which duration of woody plant occupation, climate, and edaphic conditions have mediated SOC and TN responses to changes in life‐form composition are poorly understood. We addressed these issues at a desert grassland site in Arizona, USA, where the leguminous shrub velvet mesquite (Prosopis velutina) has proliferated along an elevation/precipitation/temperature gradient and on contrasting soil morphologic surfaces.

On sandy loam complexes of mid‐Holocene origin, mean SOC and TN of soils in the grassland matrix increased ∼68% and ∼45%, respectively, with increasing elevation. Soil organic carbon pools were comparable and TN pools were ∼23% higher in Pleistocene‐aged clay loam complexes co‐occurring with Holocene‐aged soils at the upper elevation/climatic zone. Across the site, belowground resources associated with largeProsopisplants were 21–154% (SOC) and 18–127% (TN) higher than those in the grassy matrix.

The variance in SOC and TN pools accounted for byProsopisstem size (a rough surrogate for time of site occupation) was highest at the low‐ and mid‐elevation sites (69–74%) and lowest at the upper elevation site (32–38%). Soil δ15N values ranged from 5.5‰ to 6.7‰ across the soil/elevation zones but were comparable in herbaceous and shrub‐impacted soils and exhibited a weak relationship withProsopisbasal stem diameter (r2< 0.1) and TN (r2< 0.08). The SOC δ13C values decreased linearly with increasingProsopisbasal diameter, suggesting that size and isotopic composition of the SOC pool is a function of time ofProsopissite occupation. Isotopic mixture models indicate that encroachment of C3woody plants has also promoted SOC additions from C4plant sources, indicative of long‐term herbaceous facilitation. Grassy sites in contrasting soil/elevation combinations, initially highly distinctive in their SOC pool size and δ13C, appear to be converging on similar values following ∼100 years of woody plant proliferation.
PREDICTING LEAF PHYSIOLOGY FROM SIMPLE PLANT AND CLIMATE ATTRIBUTES: A GLOBAL GLOPNET ANALYSIS
Authors: Reich Peter B. , Wright Ian J. , Lusk Christopher H.
Published: October 2007

Knowledge of leaf chemistry, physiology, and life span is essential for global vegetation modeling, but such data are scarce or lacking for some regions, especially in developing countries. Here we use data from 2021 species at 175 sites around the world from the GLOPNET compilation to show that key physiological traits that are difficult to measure (such as photosynthetic capacity) can be predicted from simple qualitative plant characteristics, climate information, easily measured (“soft”) leaf traits, or all of these in combination. The qualitative plant functional type (PFT) attributes examined are phylogeny (angiosperm or gymnosperm), growth form (grass, herb, shrub, or tree), and leaf phenology (deciduous vs. evergreen). These three PFT attributes explain between one‐third and two‐thirds of the variation in each of five quantitative leaf ecophysiological traits: specific leaf area (SLA), leaf life span, mass‐based net photosynthetic capacity (Amass), nitrogen content (Nmass), and phosphorus content (Pmass). Alternatively, the combination of four simple, widely available climate metrics (mean annual temperature, mean annual precipitation, mean vapor pressure deficit, and solar irradiance) explain only 5–20% of the variation in those same five leaf traits. Adding the climate metrics to the qualitative PFTs as independent factors in the model increases explanatory power by 3–11% for the five traits. If a single easily measured leaf trait (SLA) is also included in the model along with qualitative plant traits and climate metrics, an additional 5–25% of the variation in the other four other leaf traits is explained, with the models accounting for 62%, 65%, 66%, and 73% of global variation in Nmass, Pmass, Amass, and leaf life span, respectively. Given the wide availability of the summary climate data and qualitative PFT data used in these analyses, they could be used to explain roughly half of global variation in the less accessible leaf traits (Amass, leaf life span, Nmass, Pmass); this can be augmented to two‐thirds of all variation if climatic and PFT data are used in combination with the readily measured trait SLA. This shows encouraging possibilities of progress in developing general predictive equations for macro‐ecology, global scaling, and global modeling.
PATTERNS OF HOUSES AND HABITAT LOSS FROM 1937 TO 1999 IN NORTHERN WISCONSIN, USA
Authors: Gonzalez-Abraham Charlotte E. , Radeloff Volker C. , Hawbaker Todd J. , Hammer Roger B. , Stewart Susan I. , Clayton Murray K.
Published: October 2007

Rural America is witnessing widespread housing development, which is to the detriment of the environment. It has been suggested to cluster houses so that their disturbance zones overlap and thus cause less habitat loss than is the case for dispersed development. Clustering houses makes intuitive sense, but few empirical studies have quantified the spatial pattern of houses in real landscapes, assessed changes in their patterns over time, and quantified the resulting habitat loss. We addressed three basic questions: (1) What are the spatial patterns of houses and how do they change over time; (2) How much habitat is lost due to houses, and how is this affected by spatial pattern of houses; and (3) What type of habitat is most affected by housing development. We mapped 27 419 houses from aerial photos for five time periods in 17 townships in northern Wisconsin and calculated the terrestrial land area remaining after buffering each house using 100‐ and 500‐m disturbance zones. The number of houses increased by 353% between 1937 and 1999. Ripley'sKtest showed that houses were significantly clustered at all time periods and at all scales. Due to the clustering, the rate at which habitat was lost (176% and 55% for 100‐ and 500‐m buffers, respectively) was substantially lower than housing growth rates, and most land area was undisturbed (95% and 61% for 100‐m and 500‐m buffers, respectively). Houses were strongly clustered within 100 m of lakes. Habitat loss was lowest in wetlands but reached up to 60% in deciduous forests. Our results are encouraging in that clustered development is common in northern Wisconsin, and habitat loss is thus limited. However, the concentration of development along lakeshores causes concern, because these may be critical habitats for many species. Conservation goals can only be met if policies promote clustered development and simultaneously steer development away from sensitive ecosystems.
ATMOSPHERIC DEPOSITION MAY AFFECT NORTHERN HARDWOOD FOREST COMPOSITION BY ALTERING SOIL NUTRIENT SUPPLY
Authors: Zaccherio Meredith T. , Finzi Adrien C.
Published: October 2007

In the northeastern United States, the input of reactive nitrogen (N) via atmospheric deposition has increased rapidly since the onset of the industrial revolution. During the same period of time, acid precipitation and forest harvest have removed substantial quantities of base cations from soil. Because of the dominance of base‐poor soils and the low rates of atmospheric base cation deposition, soils throughout the northeastern United States may be increasingly rich in N but poor in calcium (Ca). We studied the consequences of a change in soil N and Ca availability on forest composition by transplanting seedlings of four tree species into replicate plots in the understory and in canopy gaps amended with N and Ca in factorial combination. In this paper, we report on the growth and survivorship of seedlings over a four‐year period.

Relative to control plots, fertilization with N increased red maple growth by an average of 39% whereas fertilization with Ca decreased survivorship in the understory by 41%. In sugar maple, fertilization with Ca increased growth by 232% and 46% in the forest understory and in canopy gaps, respectively, and significantly increased high light survivorship. Fertilization with N decreased white pine survivorship by 69% in the understory whereas high Ca availability significantly increased survivorship. Fertilization with N or Ca alone reduced red oak growth but had no effect on survivorship. The results of this study suggest that historical losses of soil Ca and the continuing effects of atmospheric‐N deposition on N availability are likely to alter the composition of northeastern North American forests because of the positive effects of N enrichment on the growth of red maple and the negative effects of Ca loss on the growth and survivorship of sugar maple and white pine.
MODELING THE FOREST TRANSITION: FOREST SCARCITY AND ECOSYSTEM SERVICE HYPOTHESES
Authors: Satake Akiko , Rudel Thomas K.
Published: October 2007

An historical generalization about forest cover change in which rapid deforestation gives way over time to forest restoration is called “the forest transition.” Prior research on the forest transition leaves three important questions unanswered: (1) How does forest loss influence an individual landowner's incentives to reforest? (2) How does the forest recovery rate affect the likelihood of forest transition? (3) What happens after the forest transition occurs? The purpose of this paper is to develop a minimum model of the forest transition to answer these questions. We assume that deforestation caused by landowners' decisions and forest regeneration initiated by agricultural abandonment have aggregated effects that characterize entire landscapes. These effects include feedback mechanisms called the “forest scarcity” and “ecosystem service” hypotheses. In the forest scarcity hypothesis, forest losses make forest products scarcer, which increases the economic value of forests. In the ecosystem service hypothesis, the environmental degradation that accompanies the loss of forests causes the value of ecosystem services provided by forests to decline. We examined the impact of each mechanism on the likelihood of forest transition through an investigation of the equilibrium and stability of landscape dynamics. We found that the forest transition occurs only when landowners employ a low rate of future discounting. After the forest transition, regenerated forests are protected in a sustainable way if forests regenerate slowly. When forests regenerate rapidly, the forest scarcity hypothesis expects instability in which cycles of large‐scale deforestation followed by forest regeneration repeatedly characterize the landscape. In contrast, the ecosystem service hypothesis predicts a catastrophic shift from a forested to an abandoned landscape when the amount of deforestation exceeds the critical level, which can lead to a resource degrading poverty trap. These findings imply that incentives for forest conservation seem stronger in settings where forests regenerate slowly as well as when decision makers value the future.
SUBLETHAL PESTICIDE CONCENTRATIONS AND PREDATION JOINTLY SHAPE LIFE HISTORY: BEHAVIORAL AND PHYSIOLOGICAL MECHANISMS
Authors: Campero Melina , Slos Stefanie , Ollevier Frans , Stoks Robby
Published: October 2007

Despite their relevance for risk assessment, the interactive effects of pesticide and predation cues are poorly understood because the underlying behavioral and physiological mechanisms are largely unknown. To explore these mechanisms, we reared larvae of the damselfly Coenagrion puella at three different predation risk levels and a range of environmentally realistic concentrations of three pesticides used worldwide (atrazine, carbaryl, and endosulfan). We compared key development responses (growth rate, developmental time, and final size) against food ingestion, assimilation, and conversion efficiency, and acetylcholinesterase (AChE) activity. Predation risk impaired all endpoints, including AChE activity, while the effects of pesticide stress were smaller for atrazine and endosulfan and absent for carbaryl. The effects of both stressors and their interaction on life history were mostly indirect through resource acquisition and energy allocation. Compensatory physiological mechanisms to pesticide stress (atrazine and endosulfan) were present in larvae reared in the absence of predation stress but were offset under predation stress. As a result, smaller size (atrazine and endosulfan) and lower growth rate (endosulfan) from pesticide stress were only found in the highest predation risk treatment. Our results provide insight as to the conditions under which interactions between stressors are likely to occur: damselfly populations at high density and living in fish ponds will be more affected by pesticides than populations at low densities in fishless ponds. By identifying variables that may shape the interaction between predation stress and other stressors such as pesticides, our mechanistic approach may help to bridge the gap between laboratory and field studies.