bluuebunny/crossref_metadata_2025 huggingface dataset:
Neurologic Music Therapy in Cognitive Rehabilitation
Authors: Thaut Michael H.
Published: April 2010

NEUROLOGIC MUSIC THERAPY LAST CAME INTO research and clinical focus via cognitive rehabilitation. New imaging techniques studying higher cognitive functions in the human brain 'in vivo' and theoretical advancements in music and brain function have facilitated this development. There are shared cognitive and perceptual mechanisms and shared neural systems between musical cognition and parallel nonmusical cognitive functions that provide access for music to affect general nonmusical functions, such as memory, attention, and executive function. The emerging clinical literature shows substantial support for these effects in rehabilitative retraining of the injured brain. Key findings relevant for clinical applications of neurologic music therapy to cognitive rehabilitation are presented and discussed below.
Music and Autonomic Nervous System (Dys)Function
Authors: Ellis Robert J. , Thayer Julian F.
Published: April 2010

DESPITE A WEALTH OF EVIDENCE FOR THE INVOLVEMENT of the autonomic nervous system (ANS) in health and disease and the ability of music to affect ANS activity, few studies have systematically explored the therapeutic effects of music on ANS dysfunction. Furthermore, when ANS activity is quantified and analyzed, it is usually from a point of convenience rather than from an understanding of its physiological basis. After a review of the experimental and therapeutic literatures exploring music and the ANS, a "Neurovisceral Integration" perspective on the interplay between the central and autonomic nervous systems is introduced, and the associated implications for physiological, emotional, and cognitive health are explored. The construct of heart rate variability is discussed both as an example of this complex interplay and as a useful metric for exploring the sometimes subtle effect of music on autonomic response. Suggestions for future investigations using musical interventions are offered based on this integrative account.
Listening to Filtered Music as a Treatment Option for Tinnitus: A Review
Authors: Ellis E. Courtenay Wilson , Schlaug Gottfried , Pantev Christo
Published: April 2010

TINNITUS IS THE PERCEPTION OF A SOUND IN THE absence of an external acoustic stimulus and it affects roughly 10-15% of the population. This review will discuss the different types of tinnitus and the current research on the underlying neural substrates of subjective tinnitus. Specific focus will be paid to the plasticity of the auditory cortex, the inputs from non-auditory centers in the central nervous system and how these are affected by tinnitus. We also will discuss several therapies that utilize music as a treatment for tinnitus and highlight a novel method that filters out the tinnitus frequency from the music, leveraging the plasticity in the auditory cortex as a means of reducing the impact of tinnitus.
Nested Inversions: Genre and the Bipartite Form of Herman Melville's Pierre
Authors: Crimmins Jonathan
Published: April 2010

Jonathan Crimmins, "Nested Inversions: Genre and the Bipartite Form of Herman Melville's Pierre" (pp. 437–464)

In this essay I suggest that Herman Melville constructed Pierre (1852) as a diptych, an early example of the form that he later employed in his stories for Harper's and Putnam's magazines. He characterized Pierre's two halves by their settings, countryside and city, and used the locales allegorically to represent the ideological value systems associated with the mode of production of each. Further, I argue that Melville constrained the scope of the mixed form, more freely practiced in Mardi (1849) and Moby-Dick (1851), by carefully aligning the generic elements of Pierre with its bipartite structure: the sentimental and the Gothic with the first half of the novel, the urban and romantic with the second half. subordinating the generic elements to the structure, Melville built a novel in which each half operates according to different laws, each as its own separate stage, enacting the drama of its treasured beliefs and the inescapable hypocrisies of those beliefs. Each half of Pierre presents the justice of its values as natural and the logic of its values as complete. And yet, set side-by-side as a diptych so as to suggest equal measure, the competing claims to totality collapse; while each ideological stage acts as if its value systems are unified and whole, side-by-side they are seen as inverted schematics, as two halves of a single crisis. Melville shows the contradictory dependence of capitalism's ideology of historical contingency and feudalism's faith in an idealist grounding of the historical, offering up the insolubility of the crisis as the empty indicator of a real solution.
Inherited Emotions: George Eliot and the Politics of Heirlooms
Authors: Osborne Katherine Dunagan
Published: April 2010

Katherine Dunagan Osborne, "Inherited Emotions: George Eliot and the Politics of Heirlooms" (pp. 465–493)

This essay removes George Eliot's heroines from heterosexual dyads to focus on the roles that things play in women's autonomous moral and sexual development. Because Eliot's female protagonists can adapt heirlooms for their own private and emotional purposes, they can replace traditional inheritance based on bloodlines with a non-familial, emotional inheritance, thus illustrating the subtlety of Eliot's family and gender politics. This reading of Eliot contextualizes specific heirlooms in Middlemarch (1871–72) and Daniel Deronda (1876)—including miniature portraits, emeralds, turquoises, and diamonds—to reveal the surprising politics embedded in Eliot's heirlooms that her nineteenth-century readers would certainly have recognized.
Glucocorticoid replacement therapy and vertebral fractures in hypopituitary adult males with GH deficiency
Authors: Mazziotti G , Porcelli T , Bianchi A , Cimino V , Patelli I , Mejia C , Fusco A , Giampietro A , De Marinis L , Giustina A
Published: April 2010

Objective

GH deficiency (GHD) and glucocorticoid excess are associated with increased risk of fragility fractures. We aimed to evaluate whether the prevalence of vertebral fractures may be influenced by glucocorticoid over-replacement in hypopituitary males with GHD.

Design

Cross-sectional study.

Methods

Fifty-one adult hypopituitary patients (all males; mean age 55 years, range: 23–81) with severe adult-onset GHD (replaced in 21 patients and untreated in 30 patients) and glucocorticoid deficiency on replacement treatment were studied for vertebral fractures using a radiological and morphometric approach.

Results

Vertebral fractures were observed in 31 patients (60.8%) in correlation with untreated GHD, urinary cortisol values, and cortisone doses. Patients were stratified according to treatment of GHD, and current and cumulative cortisone doses. In untreated GHD, vertebral fractures occurred more frequently in patients who had received higher (greater than median) cumulative and current doses of cortisone compared with patients who had received lower (less than median) drug doses (95.2 vs 50.0%, P=0.009 and 90.5 vs 55.6%, P=0.04 respectively). In untreated GHD, fractured patients had significantly higher urinary cortisol values compared with patients without vertebral fractures (84 μg/24 h, range: 24–135 vs 49 μg/24 h, range: 30–96; P=0.04). In treated GHD patients, by contrast, the prevalence of vertebral fractures was not influenced by cumulative and current cortisone doses and urinary cortisol values.

Conclusions

Glucocorticoid over-replacement may increase the prevalence of vertebral fractures in patients with untreated GHD. However, treatment of GHD seems to protect the skeleton from the deleterious effects of glucocorticoid overtreatment in hypopituitary patients.
The Contribution of Work and Non‐work Factors to the Onset of Psychological Distress: An Eight‐year Prospective Study of a Representative Sample of Employees in Canada
Authors: Marchand Alain , Blanc Marie‐Eve
Published: April 2010

The Contribution of Work and Non‐work Factors to the Onset of Psychological Distress: An Eight‐year Prospective Study of a Representative Sample of Employees in Canada: Alain Marchand, et al. School of Industrial Relations, University of Montreal, Canada

Objectives

This study examined how occupation and work organization conditions contributed, over 8 yr, to the onset of psychological distress after adjusting for non‐work and individual characteristics.

Methods

The data came from the five cycles (Cycle 1=1994–1995, Cycle 5=2002–2003) of Statistics Canada's National Population Health Survey. A sample of 5,270 workers nested in 1,122 neighborhoods and aged 15 to 55 yr with no psychological distress at baseline was analyzed with discrete time survival multilevel regression models.

Results

The onset of psychological distress decreased over time. Occupation was not significant, whereas social support at work decreased the risk. Substantial effects for non‐work and individual factors were found, including neighborhood, social support outside the workplace, demographics, physical health, personality traits, and life habits.

Conclusions

This study found that work characteristics made a limited contribution to the onset of psychological distress, but social support in the workplace clearly proved to be an important protective factor. Enterprises must pay special attention to how colleagues and supervisors act to help workers complete tasks.
Analysis of infliximab treated pediatric patients with Crohn disease in Hungary
Authors: Veres Gábor , Szabó Dolóresz , Várkonyi Ágnes , Tari Beáta , Polgár Marianne , B. Kovács Judit , Horváth Ágnes , Tomsits Erika , Tokodi István , Bodánszky Hedvig , Dezsőfi Antal , Szakos Erzsébet , Vass Noémi , Ruszinkó Viktória , Kovács Márta , Müller Katalin Eszter , Arató András
Published: April 2010

A terápiarezisztens, súlyos Crohn-beteg gyermekek kezelésére új lehetőséget nyújt az antitumornekrózis-faktor-α-terápia (infliximab). Jelen vizsgálat célja az infliximabterápia hatékonyságának, mellékhatásainak felmérése hazánkban, a gyógyszer gyermekgyógyászati alkalmazásának engedélyezésétől a 2008. december 31-ig terjedő időszakban. A vizsgált periódusban országosan 23 gyermek részesült infliximabkezelésben. Az indukciós terápia során a betegek 5 mg/ttkg infliximabot kaptak a 0., a 2. és a 6. héten, ahol meghatároztuk a betegség aktivitását jelző mutatót (pediatric Crohn disease activity index). Az infliximabkezelés során kedvező terápiás választ 18 betegnél (81,8%) tapasztaltunk, teljes remisszióba 13 gyermek került (59,1%). A számításokat 22 beteg adatai alapján végeztük. A kezelés 6. hetére a fistulák 70%-a bezárult. A gyógyszerrel összefüggésbe hozható akut infúziós reakció 2 betegnél jelentkezett, egy másik esetben anaphylaxiás reakció alakult ki. Késői mellékhatás három gyermeknél jelentkezett. A vizsgálatunkban részt vett, hagyományos terápiára rezisztens, súlyos Crohn-betegek döntő többségénél az indukciós infliximabterápia hatásosnak bizonyult.
Primary refractory and relapsed Hodgkin-lymphoma patients
Authors: Miltényi Zsófia , Simon Zsófia , Páyer Edit , Váróczy László , Gergely Lajos , Illés Árpád
Published: April 2010

Napjainkban a legtöbb Hodgkin-lymphomás beteg meggyógyítható a korszerű kezelési módszerekkel, sajnos a betegek néhány százaléka refrakter, és közel harmaduk relabál az elsődleges kezelést követően.Célkitűzés és módszer:a DEOEC III. sz. Belgyógyászati Klinikán 1996 és 2006 között kezelt Hodgkin-lymphomás beteg között vizsgáltuk retrospektív módszerrel a refrakter esetek és a relapszusok előfordulását.Eredmények:76 nő és 71 férfi esetében diagnosztizáltunk Hodgkin-lymphomát ezen idő alatt. A betegek 95,9%-a került remisszióba az elsődleges kezelésre. 6 nőbeteg volt primeren refrakter, 4 betegnél autológ hemopoetikus őssejttranszplantáció is történt, de a többszörös kezelések ellenére is mindannyian exitáltak. 31 betegnél alakult ki relapszus (1 éven belül 16 esetben). 14 betegnél történt autológ hemopoetikus őssejttranszplantáció, 11 beteg csak kemoterápiában, 3 csak irradiációban és 3 beteg kombinált kezelésben részesült. A relabált betegek közül öten alapbetegségük progressziója, egy beteg szekunder myelodysplasia miatt exitált.Következtetések:a relabált betegek prognózisa a további kezelések mellett jó lehet, de a refrakter betegek hosszú távú esélyei rendkívül rosszak még autológ-, és akár allogén hemopoetikus őssejttranszplantáció mellett is, így rendkívül fontos az újabb kezelési módszerek keresése.
Energetic relationships for crushing of soil clods
Authors: Patay István , Sándor Virág
Published: April 2010

Clod crushing is a principal problem with soils of high clay content.
Therefore, there is a need for determining the conditions for clod breaking and
clod crushing. The objective of the work was to develop a special purpose tool
for single clod breaking both by rigid support of the clod and by a single clod
supported by soil and to develop a machine for clod crushing. Furthermore, the
purpose was to determine the relationship between the specific energy
requirement for clod crushing in the function of soil plasticity and the soil
moisture content by the means of the developed tool and machine. The main
result of the experiments is summarized in a 3D diagram where the specific
energy requirement for soil clod crushing is given in the function of the
moisture content and the plasticity index for different clay soils.
Single Crystal Boron-Doped Diamond Synthesis
Authors: Grotjohn Timothy , Nicley Shannon , Tran Dzung , Reinhard Donnie K. , Becker Michael , Asmussen Jes
Published: April 2010

The electrical characteristics of high quality single crystal boron-doped diamond are studied. Samples are synthesized in a high power-density microwave plasma-assisted chemical vapor deposition (CVD) reactor at pressures of 130-160 Torr. The boron-doped diamond films are grown using diborane in the feedgas at concentrations of 1 to 50 ppm. The boron acceptor concentration is investigated using infrared absorption and a four point probe is used to study the conductivity. The temperature dependent conductivity is analyzed to determine the boron dopant activation energy.
Single-Walled Carbon Nanotube Growth using Al2Ox Buffer Layer at Low Temperature by Alcohol Gas Source Method
Authors: Sato Kuninori , Maruyama Takahiro , Naritsuka Shigeya
Published: April 2010

Aluminum oxide (Al2Ox) buffer layers were employed to grow single-walled carbon nanotubes (SWNTs) at 400°C using an alcohol gas source and a Co catalyst. By optimizing the thickness of the aluminum oxide layer, the SWNT yield was enhanced by a factor of several times. In addition, SWNT growth at 350°C was realized on the Al2Ox buffer layer by this method. Raman measurements at various excitation wavelengths suggest that a Al2Ox buffer layer preferentially enhances the growth of SWNTs with larger diameters (>1 nm).
Red-Green-Blue MOSLED Made by PECVD Grown SiOx with Detuning RF Plasma Power
Authors: Cheng Chih-Hsien , Lai Bo-Han , Lin Gong-Ru
Published: April 2010

Si quantum dot (Si-QD) based multi-color metal oxide semiconductor lighting emission diodes (MOSLEDs) made on Si-rich SiOx grown by detuning RF plasma power in a plasma enhanced chemical vapor deposition (PECVD) system are demonstrated. With the RF plasma powers increasing from 50 to 70 W at 10 W increment, the turn-on voltage and maximum electroluminescence (EL) power red-, green- and blue-color MOSLEDs increase from 70, 90 and 99 V and 7, 26 and 55 nW, respectively. The power-current slope of 0.51, 3.24 and 53.82 mW/A are obtained for these MOSLEDs with corresponding power conversion ratio (PCR) of 5.13×10-6, 2.52×10-5 and 2.47×10-4. Both the turn-on voltage and power slope linearly increase with enhancing thickness of the Si-QD based MOSLED.
Investigation of Joule Heating Effect in Various Stages of Electromigration in Flip-chip Solder Joints by Infrared Microscopy
Authors: Hsiao Hsiang Yao , Chen Chih , Yao D. J.
Published: April 2010

The Joule heating effect at various stages under electromigration of flip-chip Sn3.5Ag solder joints was investigated under a current of 0.5 A at 100°C. During various stages of electromigration, voids may form and propagate and Joule heating effect may vary at different void sizes. To verify the void nucleation and propagation on Joule heating effect during electromigration process, the solder bump was stressed for different lengths of time and then examined by Kelvin bump probes and infrared microscopy. We found that voids started to form at approximately 1.2 times of the initial bump resistance. Then the voids propagated when the bump resistance increased. In addition, the temperature of the solder joints increased with the bump resistance and the increase of current stressing time. It increased very slowly in initial stages. In the last stage, the temperature of the solder bump increased rapidly due to the increase of the bump resistance and the local Joule heating effect.
Transition from coherent to ohmic conductance explained by a statistical model for the effects of decoherence
Authors: Zilly Matías , Ujsághy Orsolya , Wolf Dietrich E.
Published: April 2010

Using a statistical model for the effects of decoherence [1], we show that in linear tight-binding samples ohmic conductance (resistance proportional to length) is reached for any finite density p of decoherence sites, if the chemical potential μ of the contacts is within a conducting band. If μ is outside a band, or if due to disorder, no bands form, for high decoherence densities p>p* still ohmic conductance is reached, where p* is a critical decoherence density. For p<p*, the sample resistance increases exponentially with the length.
Natural analogues of degraded ecosystems enhance conservation and reconstruction in extreme environments
Authors: Richardson Paul J. , Lundholm Jeremy T. , Larson Douglas W.
Published: April 2010

Ecosystem rehabilitation strategies are grounded in the concept that coexisting species fit their environments as an outcome of natural selection operating over ecological and evolutionary timescales. From this perspective, re‐creation of historical environmental filters on community assembly is a necessary first step to recovering biodiversity within degraded ecosystems; however, this approach is often not feasible in severely damaged environments where extensive physiochemical changes cannot be reversed. Under such circumstances management goals may shift from restoring historical conditions to reconstructing entirely new ecosystems or replicating natural ecosystems that may be locally novel but of regional conservation importance. This latter goal may be achieved by introducing to damaged sites species already adapted to filters maintaining the degraded state, through targeting assemblages from natural ecosystems biophysically analogous to the degraded state, here termed “degraded‐state analogue” (DSA) ecosystems. This hypothesis predicts that, in high‐stress sites where recruitment of previous inhabitants is strongly microsite‐limited, DSA species will be primarily propagule‐limited; furthermore, communities invaded by DSA species should shift in structure to reflect properties associated with high‐value DSA target ecosystems.

We tested these predictions by experimentally sowing long‐abandoned limestone quarry floors with 18 perennial grass and forb species characteristic of rare natural limestone pavements called “alvars.” Alvar species established successfully under a range of microsite conditions manipulated to alter suspected constraints on colonization, including nitrogen deficiency, excessive CaCO3, and competition with weeds. Alvar species performed equivalently to seeded weed species known to thrive on quarry floors. Resident communities doubled in species richness following alvar species addition, supporting 17–20 species/0.18 m2(95% confidence interval) and providing refuge to regionally restricted or threatened species includingIris lacustris,Solidago ptarmicoides, andLiatris cylindracea. In contrast, maximum‐diversity reference plots on a pristine alvar supported 20–23 species/0.18 m2. Strong propagule limitation but weak microsite constraints on quarry colonization by alvar species combined with establishment of species‐rich communities comparable to natural alvar biodiversity hot spots confirms that targeting DSA assemblages in ecosystem reconstruction can promote both efficient site colonization and ex situ biodiversity conservation within difficult‐to‐restore anthropogenic wastelands.
Reproduction of Echinacea angustifolia in fragmented prairie is pollen‐limited but not pollinator‐limited
Authors: Wagenius Stuart , Lyon Stephanie Pimm
Published: April 2010

Pollen limitation of plant reproduction occurs in many plant species, particularly those in fragmented habitat; however, causes of pollen limitation are often unknown. We investigated the relationship between pollen limitation and pollinator visitation in the purple coneflower, Echinacea angustifolia (Asteraceae), which grows in the extremely fragmented tallgrass prairie of North America. Previous investigations showed that pollen limitation of E. angustifolia increases with plant isolation and decreases with population size. We observed insect visitation to E. angustifolia over two flowering seasons and estimated pollen limitation of observed plants, using seed set as a proxy measure in 2004 and persistence of receptive style rows in 2005. We analyzed spatial patterns of bee visitation and pollination at two spatial scales: individual isolation, as measured by the distance to their kth nearest flowering neighbors (k = 1 −15), and population size. Our results indicate that E. angustifolia is pollinated by over 26 species of native bees, with 70–75% of visits by halictid bees. Surprisingly, in both years, bee visitation increased with isolation of individual plants and did not vary significantly with population size. As expected, plant isolation increased pollen limitation and lowered seed set. There was no effect of population size on seed set in 2004, and pollen limitation decreased nonsignificantly with population size in 2005. We conclude that pollen receipt limits reproduction in E. angustifolia, but pollinator visitation does not. Remarkably, isolated plants simultaneously have increased rates of pollinator visitation by pollinators and decreased reproduction. We discuss alternative explanations of pollen limitation that are consistent with this apparent discrepancy, including a decline in the availability of compatible conspecific pollen with increased plant isolation.
High levels of green‐tree retention are required to preserve ground beetle biodiversity in boreal mixedwood forests
Authors: Work Timothy T. , Jacobs Joshua M. , Spence John R. , Volney W. Jan
Published: April 2010

Recovery of biodiversity and other ecosystem functions to pre‐disturbance levels is a central goal of natural disturbance‐based approaches to ecosystem management. In boreal mixedwood forests, green‐tree retention has been proposed as an alternative approach to traditional clearcutting that may minimize initial displacement of species assemblages and speed recovery of the biota. Here we evaluated the effectiveness of six levels of dispersed green‐tree retention for conservation of ground beetle biodiversity in four boreal mixedwood cover types that span a gradient of stand development following wildfire. Each cover type × treatment combination was replicated three times in an operational scale experiment using 10‐ha compartments. Ground beetle assemblages (59 species and 45 419 individuals) responded to increasing levels of dispersed, green‐tree retention, but even relatively high levels of retention (up to 50% retention) did not retain species assemblages characteristic of uncut forest stands. This latter effect was most pronounced in compartments in later successional stages; i.e., those with developing conifer understories, or mixed and/or conifer‐dominated overstories. Beetle assemblages in high levels of retention (50–75%) were statistically similar across all cover types, although we detected modest differences among the 5‐year recovery of assemblages, based on initial cover type differences. Thus, recovery to initial conditions likely will be slower in mixed and conifer stands than in deciduous stands. We suggest that recovery of beetle assemblages is strongly linked to stand reinitiation through deciduous “suckering” postharvest. Increasing levels of harvest appear to homogenize carabid assemblages across the four dominant cover types, and thus higher levels of retention (>50%) will be required to preserve assemblages of later successional stages. Regional renewal of assemblages, however, will require landscape‐level planning.
A mixed‐model moving‐average approach to geostatistical modeling in stream networks
Authors: Peterson Erin E. , Hoef Jay M. Ver
Published: April 2010

Spatial autocorrelation is an intrinsic characteristic in freshwater stream environments where nested watersheds and flow connectivity may produce patterns that are not captured by Euclidean distance. Yet, many common autocovariance functions used in geostatistical models are statistically invalid when Euclidean distance is replaced with hydrologic distance. We use simple worked examples to illustrate a recently developed moving‐average approach used to construct two types of valid autocovariance models that are based on hydrologic distances. These models were designed to represent the spatial configuration, longitudinal connectivity, discharge, and flow direction in a stream network. They also exhibit a different covariance structure than Euclidean models and represent a true difference in the way that spatial relationships are represented. Nevertheless, the multi‐scale complexities of stream environments may not be fully captured using a model based on one covariance structure. We advocate using a variance component approach, which allows a mixture of autocovariance models (Euclidean and stream models) to be incorporated into a single geostatistical model. As an example, we fit and compare “mixed models,” based on multiple covariance structures, for a biological indicator. The mixed model proves to be a flexible approach because many sources of information can be incorporated into a single model.
Optimal allocation of conservation effort among subpopulations of a threatened species: How important is patch quality?
Authors: Chauvenet Aliénor L. M. , Baxter Peter W. J. , McDonald-Madden Eve , Possingham Hugh P.
Published: April 2010

Money is often a limiting factor in conservation, and attempting to conserve endangered species can be costly. Consequently, a framework for optimizing fiscally constrained conservation decisions for a single species is needed. In this paper we find the optimal budget allocation among isolated subpopulations of a threatened species to minimize local extinction probability. We solve the problem using stochastic dynamic programming, derive a useful and simple alternative guideline for allocating funds, and test its performance using forward simulation. The model considers subpopulations that persist in habitat patches of differing quality, which in our model is reflected in different relationships between money invested and extinction risk. We discover that, in most cases, subpopulations that are less efficient to manage should receive more money than those that are more efficient to manage, due to higher investment needed to reduce extinction risk. Our simple investment guideline performs almost as well as the exact optimal strategy. We illustrate our approach with a case study of the management of the Sumatran tiger, Panthera tigris sumatrae, in Kerinci Seblat National Park (KSNP), Indonesia. We find that different budgets should be allocated to the separate tiger subpopulations in KSNP. The subpopulation that is not at risk of extinction does not require any management investment. Based on the combination of risks of extinction and habitat quality, the optimal allocation for these particular tiger subpopulations is an unusual case: subpopulations that occur in higher‐quality habitat (more efficient to manage) should receive more funds than the remaining subpopulation that is in lower‐quality habitat. Because the yearly budget allocated to the KSNP for tiger conservation is small, to guarantee the persistence of all the subpopulations that are currently under threat we need to prioritize those that are easier to save. When allocating resources among subpopulations of a threatened species, the combined effects of differences in habitat quality, cost of action, and current subpopulation probability of extinction need to be integrated. We provide a useful guideline for allocating resources among isolated subpopulations of any threatened species.
Changes of a mutualistic network over time: reanalysis over a 10‐year period
Authors: Díaz-Castelazo Cecilia , Guimarães Paulo R. , Jordano Pedro , Thompson John N. , Marquis Robert J. , Rico-Gray Víctor
Published: April 2010

We analyzed the structure of a multispecific network of interacting ants and plants bearing extrafloral nectaries recorded in 1990 and again in 2000 in La Mancha, Veracruz, Mexico. We assessed the replicability of the number of interactions found among species and also whether there had been changes in the network structure associated with appearance of new ant and plant species during that 10‐year period. Our results show that the nested topology of the network was similar between sampling dates, group dissimilarity increased, mean number of interactions for ant species increased, the frequency distribution of standardized degrees reached higher values for plant species, more ant species and fewer plant species constituted the core of the more recent network, and the presence of new ant and plant species increased while their contribution to nestedness remained the same. Generalist species (i.e., those with the most links or interactions) appeared to maintain the stability of the network because the new species incorporated into the communities were linked to this core of generalists. Camponotus planatus was the most extreme generalist ant species (the one with the most links) in both networks, followed by four other ant species; but other species changed either their position along the continuum of generalists relative to specialists or their presence or absence within the network. Even though new species moved into the area during the decade between the surveys, the overall network structure remained unmodified.
Marine reserves: Fish life history and ecological traits matter
Authors: Claudet J. , Osenberg C. W. , Domenici P. , Badalamenti F. , Milazzo M. , Falcón J. M. , Bertocci I. , Benedetti-Cecchi L. , García-Charton J-A. , Goñi R. , Borg J. A. , Forcada A. , de Lucia G. A. , Pérez-Ruzafa Á , Afonso P. , Brito A. , Guala I. , Diréach L. Le , Sanchez-Jerez P. , Somerfield P. J. , Planes S.
Published: April 2010

Marine reserves are assumed to protect a wide range of species from deleterious effects stemming from exploitation. However, some species, due to their ecological characteristics, may not respond positively to protection. Very little is known about the effects of life history and ecological traits (e.g., mobility, growth, and habitat) on responses of fish species to marine reserves. Using 40 data sets from 12 European marine reserves, we show that there is significant variation in the response of different species of fish to protection and that this heterogeneity can be explained, in part, by differences in their traits. Densities of targeted size‐classes of commercial species were greater in protected than unprotected areas. This effect of protection increased as the maximum body size of the targeted species increased, and it was greater for species that were not obligate schoolers. However, contrary to previous theoretical findings, even mobile species with wide home ranges benefited from protection: the effect of protection was at least as strong for mobile species as it was for sedentary ones. Noncommercial bycatch and unexploited species rarely responded to protection, and when they did (in the case of unexploited bentho‐pelagic species), they exhibited the opposite response: their densities were lower inside reserves. The use of marine reserves for marine conservation and fisheries management implies that they should ensure protection for a wide range of species with different life‐history and ecological traits. Our results suggest this is not the case, and instead that effects vary with economic value, body size, habitat, depth range, and schooling behavior.
Viral diversity and prevalence gradients in North American Pacific Coast grasslands
Authors: Seabloom Eric W. , Borer Elizabeth T. , Mitchell Charles E. , Power Alison G.
Published: April 2010

Host–pathogen interactions may be governed by the number of pathogens coexisting within an individual host (i.e., coinfection) and among different hosts, although most sampling in natural systems focuses on the prevalence of single pathogens and/or single hosts. We measured the prevalence of four barley and cereal yellow dwarf viruses (B/CYDVs) in three grass species at 26 natural grasslands along a 2000‐km latitudinal gradient in the western United States and Canada. B/CYDVs are aphid‐vectored RNA viruses that cause one of the most prevalent of all plant diseases worldwide. Pathogen prevalence and coinfection were uncorrelated, suggesting that different forces likely drive them. Coinfection, the number of viruses in a single infected host (α diversity), did not differ among host species but increased roughly twofold across our latitudinal transect. This increase in coinfection corresponded with a decline in among‐host pathogen turnover (β diversity), suggesting that B/CYDVs in northern populations experience less transmission limitation than in southern populations. In contrast to pathogen diversity, pathogen prevalence was a function of host identity as well as biotic and abiotic environmental conditions. Prevalence declined with precipitation and increased with soil nitrate concentration, an important limiting nutrient for hosts and vectors of B/CYDVs. This work demonstrates the need for further studies of processes governing coinfection, and the utility of applying theory developed to explain diversity in communities of free‐living organisms to pathogen systems.
Forest annual carbon cost: a global‐scale analysis of autotrophic respiration
Authors: Piao Shilong , Luyssaert Sebastiaan , Ciais Philippe , Janssens Ivan A. , Chen Anping , Cao Chao , Fang Jingyun , Friedlingstein Pierre , Luo Yiqi , Wang Shaopeng
Published: April 2010

Forest autotrophic respiration (Ra) plays an important role in the carbon balance of forest ecosystems. However, its drivers at the global scale are not well known. Based on a global forest database, we explore the relationships of annual Ra with mean annual temperature (MAT) and biotic factors including net primary productivity (NPP), total biomass, stand age, mean tree height, and maximum leaf area index (LAI). The results show that the spatial patterns of forest annual Ra at the global scale are largely controlled by temperature. Ra is composed of growth (Rg) and maintenance respiration (Rm). We used a modified Arrhenius equation to express the relationship between Ra and MAT. This relationship was calibrated with our data and shows that a 10°C increase in MAT will result in an increase of annual Rm by a factor of 1.9–2.5 (Q10). We also found that the fraction of total assimilation (gross primary production, GPP) used in Ra is lowest in the temperate regions characterized by a MAT of ∼11°C. Although we could not confirm a relationship between the ratio of Ra to GPP and age across all forest sites, the Ra to GPP ratio tends to significantly increase in response to increasing age for sites with MAT between 8° and 12°C. At the plant scale, direct up‐scaled Ra estimates were found to increase as a power function with forest total biomass; however, the coefficient of the power function (0.2) was much smaller than that expected from previous studies (0.75 or 1). At the ecosystem scale, Ra estimates based on both GPP – NPP and TER – Rh (total ecosystem respiration – heterotrophic respiration) were not significantly correlated with forest total biomass (P > 0.05) with either a linear or a power function, implying that the previous individual‐based metabolic theory may be not suitable for the application at ecosystem scale.
Are wetland regulations cost effective for species protection? A case study of amphibian metapopulations
Authors: Bauer Dana Marie , Paton Peter W. C. , Swallow Stephen K.
Published: April 2010

Recent declines in amphibian populations have raised concern among conservation biologists, with habitat loss and degradation due to human activities among the leading causes. The most common policies used to protect the habitat of pond‐breeding amphibians are wetland regulations that safeguard the wetland itself. However, many amphibians spend much of their adult lives foraging and over‐wintering in upland habitats and exist as metapopulations with dispersal among ponds. With no consideration of lands in the dispersal matrix, wetland policies may be ineffective at protecting amphibians or other wetland species that disperse across the landscape. This paper examined the adequacy and cost effectiveness of alternative conservation policies and their corresponding land use patterns on the long‐term persistence of pond‐breeding amphibians in exurban landscapes. We used computer simulations to compare outcomes of wetland buffer policies and broader landscape‐wide conservation policies across a variety of landscape scenarios, and we conducted sensitivity analyses on the model's species parameters in order to generalize our results to other wetland species. Results showed that, in the majority of human‐dominated landscapes, some amount of dispersal matrix protection is necessary for long‐term species persistence. However, in landscapes with extremely low‐intensity land use (e.g., low‐density residential housing) and high pond density, wetland buffer policies may be all that is required. It is not always more cost effective to protect core habitat over the dispersal matrix, a common conservation practice. Conservation costs that result from forgone residential, commercial, or agricultural activities can vary substantially but increase in a nonlinear manner regardless of land use zoning. There appears to be a threshold around an average habitat patch occupancy level of 80%, after which opportunity costs rise dramatically.
Unlocking the forest inventory data: relating individual tree performance to unmeasured environmental factors
Authors: Lichstein Jeremy W. , Dushoff Jonathan , Ogle Kiona , Chen Anping , Purves Drew W. , Caspersen John P. , Pacala Stephen W.
Published: April 2010

Geographically extensive forest inventories, such as the USDA Forest Service's Forest Inventory and Analysis (FIA) program, contain millions of individual tree growth and mortality records that could be used to develop broad‐scale models of forest dynamics. A limitation of inventory data, however, is that individual‐level measurements of light (L) and other environmental factors are typically absent. Thus, inventory data alone cannot be used to parameterize mechanistic models of forest dynamics in which individual performance depends on light, water, nutrients, etc. To overcome this limitation, we developed methods to estimate species‐specific parameters (θG) relating sapling growth (G) to L using data sets in which G, but not L, is observed for each sapling. Our approach involves: (1) using calibration data that we collected in both eastern and western North America to quantify the probability that saplings receive different amounts of light, conditional on covariates x that can be obtained from inventory data (e.g., sapling crown class and neighborhood crowding); and (2) combining these probability distributions with observed G and x to estimate θG using Bayesian computational methods. Here, we present a test case using a data set in which G, L, and x were observed for saplings of nine species. This test data set allowed us to compare estimates of θG obtained from the standard approach (where G and L are observed for each sapling) to our method (where G and x, but not L, are observed). For all species, estimates of θG obtained from analyses with and without observed L were similar. This suggests that our approach should be useful for estimating light‐dependent growth functions from inventory data that lack direct measurements of L. Our approach could be extended to estimate parameters relating sapling mortality to L from inventory data, as well as to deal with uncertainty in other resources (e.g., water or nutrients) or environmental factors (e.g., temperature).
Native shrub reestablishment in exotic annual grasslands: Do ecosystem processes recover?
Authors: Yelenik S. G. , Levine J. M.
Published: April 2010

The impacts of exotic plant species on ecosystem processes are well established, motivating numerous efforts to facilitate native‐species recovery. Nonetheless, how the return of native species influences ecosystem processes and how these changes feed back to influence the recovery process are poorly understood. We examined these questions in exotic annual grasslands on Santa Cruz Island, California, USA, where the removal of nonnative herbivores has led to the recovery of the native shrubs Artemisia californica and Eriogonum arborescens. To examine the influence of shrub colonization on nutrient cycling, and the mechanisms by which these changes arise, we measured available nitrogen and phosphorus, and quantified nitrogen mineralization and litterfall rates under shrubs and grasses in the field and in experimental monoculture plots. Both native shrubs altered nitrogen cycling as they colonized the grassland, but they did so in opposite directions. Eriogonum depressed nitrogen pools and mineralization rates via large inputs of nitrogen‐poor litter. In contrast Artemisia increased nitrogen and phosphorus pools and nitrogen mineralization rates. Last, to determine if shrub effects on soils favor shrubs or grasses, we conducted a nitrogen and phosphorus fertilization experiment in the field. Only the exotic grass was significantly limited by nitrogen. Thus the depressed nitrogen availability associated with Eriogonum colonization is more harmful to exotic grasses than to the native shrub. By contrast, the elevated nitrogen associated with recovering Artemisia favors grasses over the shrub, possibly hindering recovery of the native. Mechanistic studies of the ecosystem impacts of native‐plant recovery are useful for managers wishing to predict which native species return ecosystem function, and whether such changes feed back to influence native recovery.
Icing events trigger range displacement in a high‐arctic ungulate
Authors: Stien Audun , Loe Leif Egil , Mysterud Atle , Severinsen Torbjørn , Kohler Jack , Langvatn Rolf
Published: April 2010

Despite numerous studies of how climate change may affect life history of mammals, few have documented the direct impact of climate on behavior. The Arctic is currently warming, and rain‐on‐snow and thaw–freeze events leading to ice formation on the ground may increase both in frequency and spatial extent. This is in turn expected to be critical for the winter survival of arctic herbivores. Svalbard reindeer (Rangifer tarandus plathyrynchus) have small home ranges and may therefore be vulnerable to local “locked pasture” events (ice layers limit access to plant forage) due to ground‐ice formation. When pastures are “locked,” Svalbard reindeer are faced with the decision of staying and live off a diminishing fat store, or trying to escape beyond the unknown spatial borders of the ice. We demonstrate that Svalbard reindeer do the latter, as icing events cause an immediate increase in range displacement between 5‐day observations. Population‐level responses of previous icing events may therefore not accurately predict future responses if the spatial extent of icing increases. The impact of single events may be more severe if it exceeds the maximum movement distances, so that the spatial displacement strategy reported here no longer buffers climate effects.
Plant‐available organic and mineral nitrogen shift in dominance with forest stand age
Authors: LeDuc Stephen D. , Rothstein David E.
Published: April 2010

Studies of soil nitrogen (N) availability over stand development have almost exclusively focused on mineral N, yet we increasingly recognize that plants can take up organic N in the form of free amino acids at biologically important rates. We investigated amino‐acid and mineral N availability along a 10‐site chronosequence of jack pine stands, varying in age from 4 to 60 yr following wildfire. We measured free amino‐acid N and mineral N in soil extracts; native proteolytic rates; net N mineralization rates; and microbial amino‐acid consumption via a 15N leucine tracer assay in 6 of the 10 sites (4, 10, 18, 22, 46, and 55‐yr‐old). Amino‐acid N was consistently low in the youngest sites (4–10 yr), increased rapidly in mid‐aged sites (15–22 yr), and was highest in stand age 46. In contrast, mineral N exhibited a parabolic shape (R2 = 0.499; P < 0.0001), with the youngest site and the four oldest sites containing the highest amounts of mineral N. As a result, amino‐acid N as a percentage of amino‐acid N + mineral N was greatest in mid‐aged stands (e.g., 67% in the 22‐yr‐old stand). We observed no trend in proteolytic rates across the chronosequence (P = 0.632). Percentage 15N tracer recovery was lowest in the extractable organic N pool for the 4, 10, and 18‐yr‐old sites, though only site age 10 was significantly different from the older sites. Percentage of recovery in the organic N pool was significantly positively related (R2 = 0.798; P < 0.05) to standing pools of amino‐acid N. Overall, our results suggest that heterotrophic consumption, not production via proteolysis, controls soil free amino‐acid availability. Higher microbial demand for free amino acids in younger vs. older sites likely results from greater microbial C and N limitation early in stand development due to the lack of fresh litter inputs. Since amino‐acid N exceeds mineral N in a time period of stand development where jack pine growth rates and N demand are highest, we speculate that amino‐acid N may be important to the N economy of these forests.
Nonnative grass litter enhances grazing arthropod assemblages by increasing native shrub growth
Authors: Wolkovich Elizabeth M.
Published: April 2010

Recent theory and research have highlighted how the brown (detritus‐based) world may control the trophic structure of the green (grazing) world. Detritus can alter bottom‐up control of green webs by affecting autotroph biomass and quality through its ability to alter ecosystem properties, including soil moisture and nutrient cycling. Additionally, the role of detritus as the food resource base of brown webs may subsidize omnivorous predators that can provide top‐down control of green webs. Brown–green connections may be especially important following plant invasions, which often lead to increased detritus and altered food webs. I combine field experiments, observational data, and path analysis to understand how nonnative grasses impact native arthropod communities in a semiarid shrub system. Theory and correlative evidence predict that decreased shrub growth and nutritional quality, and increased feeding of detrital predators on the grazing web, would decrease the abundance of shrub arthropods. In contrast, I found nonnative litter increased shrub growth via increased soil moisture and produced a strong bottom‐up increase of the grazing arthropod web; effects of detrital predators and plant quality were comparatively unimportant. I link these findings to the apparent lack of overlapping predators between the brown and green webs, and to the important abiotic role of litter in this xeric system, which increased native plants and the abundance and richness of arthropods on them.