bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increased hippocampal NgR1 signaling machinery in aged rats with deficits of spatial cognition
Authors: VanGuilder Starkey Heather D. , Sonntag William E. , Freeman Willard M. 
Published: February 2013

AbstractMyelin‐associated inhibitor/NgR1 signaling has important roles in modulation of synaptic plasticity, with demonstrated effects on cognitive function. We have previously demonstrated that NgR1 and its ligands are upregulated in the hippocampus of aged rats with impaired spatial learning and memory, but it is unknown whether increased expression of these proteins indicates a potential increase in pathway signaling because NgR1 requires co‐receptors for signal transduction through RhoA. Two co‐receptor complexes have been identified to date, comprised of NgR1 and LINGO‐1, and either p75 or TROY. In this study, we assessed the expression of LINGO‐1, p75 and TROY, and the downstream effector RhoA in mature adult (12 months) and aged (26 months) male Fischer 344/Brown Norway hybrid rats classified as cognitively impaired or cognitively intact by Morris water maze testing. The hippocampal distribution of NgR1 and its co‐receptors was assessed to determine whether receptor/co‐receptor interaction, and therefore signaling through this pathway, is possible. Protein expression of LINGO‐1, p75, TROY and RhoA was significantly elevated in cognitively impaired, but not intact, aged rats compared with mature adults, and expression levels correlated significantly with water maze performance. Co‐localization of NgR1 with LINGO‐1, p75 and TROY was observed in hippocampal neurons of aged, cognitively impaired rats. Further, expression profiles of NgR1 pathway components were demonstrated to classify rats as cognitively intact or cognitively impaired with high accuracy. Together, this suggests that hippocampal induction of this pathway is a conserved phenomenon in cognitive decline that may impair learning and memory by suppressing neuronal plasticity.
The dimensionality of ecological networks
Authors: Eklöf Anna , Jacob Ute , Kopp Jason , Bosch Jordi , Castro‐Urgal Rocío , Chacoff Natacha P. , Dalsgaard Bo , de Sassi Claudio , Galetti Mauro , Guimarães Paulo R. , Lomáscolo Silvia Beatriz , Martín González Ana M. , Pizo Marco Aurelio , Rader Romina , Rodrigo Anselm , Tylianakis Jason M. , Vázquez Diego P. , Allesina Stefano 
Published: February 2013

AbstractHow many dimensions (trait‐axes) are required to predict whether two species interact? This unanswered question originated with the idea of ecological niches, and yet bears relevance today for understanding what determines network structure. Here, we analyse a set of 200 ecological networks, including food webs, antagonistic and mutualistic networks, and find that the number of dimensions needed to completely explain all interactions is small ( < 10), with model selection favouring less than five. Using 18 high‐quality webs including several species traits, we identify which traits contribute the most to explaining network structure. We show that accounting for a few traits dramatically improves our understanding of the structure of ecological networks. Matching traits for resources and consumers, for example, fruit size and bill gape, are the most successful combinations. These results link ecologically important species attributes to large‐scale community structure.
Age‐related variation in reproductive traits in the wandering albatross: evidence for terminal improvement following senescence
Authors: Froy Hannah , Phillips Richard A. , Wood Andrew G. , Nussey Daniel H. , Lewis Sue 
Published: February 2013

AbstractThe processes driving age‐related variation in demographic rates are central to understanding population and evolutionary ecology. An increasing number of studies in wild vertebrates find evidence for improvements in reproductive performance traits in early adulthood, followed by senescent declines in later life. However, life history theory predicts that reproductive investment should increase with age as future survival prospects diminish, and that raised reproductive investment may have associated survival costs. These non‐mutually exclusive processes both predict an increase in breeding performance at the terminal breeding attempt. Here, we use a 30‐year study of wandering albatrosses (Diomedea exulans) to disentangle the processes underpinning age‐related variation in reproduction. Whilst highlighting the importance of breeding experience, we reveal senescent declines in performance are followed by a striking increase in breeding success and a key parental investment trait at the final breeding attempt.
Real‐time microbial adaptive diversification in soil
Authors: Gómez Pedro , Buckling Angus 
Published: February 2013

AbstractBacteria undergo adaptive diversification over a matter of days in test tubes, but the relevance to natural populations remains unclear. Here, we report real‐time adaptive diversification of the bacteriumPseudomonas fluorescensin its natural environment, soil. Crucially, adaptive diversification was much greater in the absence of the established natural microbial community, suggesting that resident diversity is likely to inhibit, rather than promote, adaptive radiations in natural environments. Rapid diversification is therefore likely to play an important role in the population and community dynamics of microbes in environments where resident communities are perturbed, such as by agriculture, pollution and antibiotics.
Means and extremes: building variability into community‐level climate change experiments
Authors: Thompson Ross M. , Beardall John , Beringer Jason , Grace Mike , Sardina Paula 
Published: February 2013

AbstractExperimental studies assessing climatic effects on ecological communities have typically applied static warming treatments. Although these studies have been informative, they have usually failed to incorporate either current or predicted future, patterns of variability. Future climates are likely to include extreme events which have greater impacts on ecological systems than changes in means alone. Here, we review the studies which have used experiments to assess impacts of temperature on marine, freshwater and terrestrial communities, and classify them into a set of ‘generations’ based on how they incorporate variability. The majority of studies have failed to incorporate extreme events. In terrestrial ecosystems in particular, experimental treatments have reduced temperature variability, when most climate models predict increased variability. Marine studies have tended to not concentrate on changes in variability, likely in part because the thermal mass of oceans will moderate variation. In freshwaters, climate change experiments have a much shorter history than in the other ecosystems, and have tended to take a relatively simple approach. We propose a new ‘generation’ of climate change experiments using down‐scaled climate models which incorporate predicted changes in climatic variability, and describe a process for generating data which can be applied as experimental climate change treatments.
Assemblage of flower visitors to Dillenia suffruticosa and possible negative effects of disturbances in Sarawak, Malaysia
Authors: Tokumoto Yuji , Itioka Takao , Ohkubo Tatsuhiro , Tadauchi Osamu , Nakagawa Michiko 
Published: February 2013

AbstractDillenia suffruticosa (Dilleniaceae), a common pioneer shrub in Southeast Asia, is broadly distributed along roadsides. This species flowers throughout the year and is thought to be a keystone species for maintaining populations of flower visitors. To examine the flower visitors of this species, we conducted field surveys and described the behaviors of each flower visitor species within four different research sites: Primary Forests 1 and 2, Secondary Forest, and Mixed Vegetation. We caught 1087 individuals belonging to 51 species from 11 insect families and one species of arachnid. Most flower visitors belonged to Hymenoptera (98.6% of individuals); Trigona spp. and Xylocopa spp. (Apidae) accounted for 64.0% and 20.0%, respectively, of all caught individuals. According to observations of behavior by each species, effective pollinators may include Xylocopa spp. and Amegilla spp. (Apidae). We compared the research results among four research sites and found that the effective pollinators were not different among sites. However, the number of species and the abundances of flower visitors decreased in disturbed areas, especially in Secondary Forest. This research suggests the effects of human disturbances on the diversity and abundance of flower visitors.
Human activity recognition based on kinematic features
Authors: Hernández J. , Cabido R. , Montemayor A. S. , Pantrigo J.J. 
Published: February 2013

AbstractThis paper proposes a new approach to recognize human actions in 2D sequences, based on real‐time visual tracking and simple feature extraction of human activities in video sequences. The proposed method emphasizes the simplicity of the strategies used, in an attempt to describe human actions as precisely as other more sophisticated (and more computationally demanding) methods in the literature. Specifically, we propose three complementary modules for the following: (a) tracking; (b) feature extraction; and (c) action recognition. The first module is based on the hybridization of a particle filter and a local search procedure and makes use of a reduced integral image to speed up the weight computation. The feature extraction module characterizes the silhouette of the tracked person by dividing it into rectangular boxes. Then, the system computes statistics on the evolution of these rectangular boxes over time. Finally, the action recognition module passes these statistics to a support vector machine to classify the actions. Experimental results show that the proposed method works in real‐time, and its performance is competitive against other state‐of‐the‐art methods.
Analysis of the fibroblast growth factor receptor (FGFR) signalling network with heparin as coreceptor: evidence for the expansion of the core FGFR signalling network
Authors: Xu Ruoyan , Rudd Timothy R. , Hughes Ashley J , Siligardi Giuliano , Fernig David G. , Yates Edwin A. 
Published: February 2013

The evolution of the fibroblast growth factor (FGF)–FGF receptor (FGFR) signalling system has closely followed that of multicellular organisms. The abilities of nine FGFs (FGF‐1 to FGF‐9; examples of FGF subfamilies 1, 4, 7, 8, and 9) and seven FGFRs or isoforms (FGFR1b, FGFR1c, FGFR2b, FGFR2c, FGFR3b, FGFR3c, and FGFR4) to support signalling in the presence of heparin, a proxy for the cellular heparan sulfate coreceptor, were assembled into a network. A connection between two FGFRs was defined as their mutual ability to signal with a particular FGF. The network contained a core of four receptors (FGFR1c, FGFR2c, FGFR3c, and FGFR4) with complete connectivity and high redundancy. Analysis of the wider network indicated that neither FGF‐3 nor FGF‐7 was well connected to this core of four receptors, and that divergence of a precursor of FGF subgroups 1, 4 and 9 from FGF subgroup 8 may have allowed expansion from a three‐member FGFR core signalling system to the four‐member core network. This increases by four‐fold the number of possible signalling combinations. Synchrotron radiation CD spectra of the FGFs with heparin revealed no overall common structural change, suggesting the existence of distinct heparin‐binding sites throughout the FGFs. The approach provides a potential method of identifying agents capable of influencing particular FGF–FGFR combinations, or areas of the signalling network, for experimental or therapeutic purposes.
Can lake restoration by fish removal improve the status of profundal macroinvertebrate assemblages?
Authors: Jyväsjärvi Jussi , Immonen Hemmo , Högmander Pia , Högmander Harri , Hämäläinen Heikki , Karjalainen Juha 
Published: February 2013

Summary

Removal of fish to restore lake pelagic food webs and water quality has been shown to increase the abundance of benthic invertebrates in shallow areas due to decreased predation pressure, while responses of profundal macroinvertebrate assemblages are less well documented.

We used multivariate analyses and a Before‐After‐Control‐Impact design to assess the impacts of fish removal (in total 101 000 kg of percid and cyprinid fish) on profundal macroinvertebrate species composition and abundance and ecological status in two basins of a eutrophic boreal lake.

In the deeper main basin, macroinvertebrate community composition and classification of ecological status were not affected by fish removal, although changes in chironomid abundance and relative abundances of predominant oligochaete taxa were observed. By contrast, in the shallower basin, community response to fish removal was more pronounced and characterised by a marked decrease in abundances of pollution‐tolerant chironomid and oligochaete taxa, resulting in change in community composition and improvement in the ecological status.

Fish removal resulted in no change in trophic state of Lake Jyväsjärvi; hence, the mechanism(s) responsible for the observed changes in profundal assemblages are unclear. A decrease in turbidity and an increase in Secchi depth suggest that concentrations of suspended solids may have decreased, resulting in lower planktic microbial production, indirectly affecting macroinvertebrate community structure.

Our results indicate that a 3‐year fish reduction may have been too short to achieve complete recovery of the benthic communities, suggesting that prolonged food‐web management together with a greater reduction in nutrient loading is needed.
Life histories of closely related amphidromous and non‐migratory fish species: a trade‐off between egg size and fecundity
Authors: Closs Gerard P. , Hicks Andy S. , Jellyman Phillip G. 
Published: February 2013

SummaryAmphidromy is a widespread migratory behavioural syndrome exhibited by fish (and some aquatic invertebrates) that spawn in fresh water and whose larvae migrate to pelagic marine (or lentic) habitats for a period of early growth, followed by a return migration to adult freshwater habitats. The fitness advantage of amphidromy has been the subject of prolonged debate, and we examined the hypothesis that amphidromy mainly increases fecundity through the production of small pelagic larvae.We compared egg size (a proxy for larval size) of closely related non‐migratory and amphidromous fish species in the familiesCottidae,Galaxiidae,Eleotridae andGobiidae. To examine how egg size changes in relation to body size within a taxonomic group, we also compared egg size and maximum body size across most species ofNewZealand non‐migratory and amphidromous galaxiids.Non‐migratory species generally have relatively larger eggs than their amphidromous confamilial species. This particular trait has evolved independently several times in each of the four families of amphidromous fish that have given rise to significant freshwater radiations. Amongst theNewZealand galaxiids, mean egg diameter increased with maximum body length for both non‐migratory and amphidromous species; however, despite the considerably smaller relative body size of the non‐diadromous species, the rate of increase in egg diameter relative to the increase in body size is considerably higher in the non‐migratory fish.We propose that amphidromous fish maintain a high level of fecundity by producing small pelagic larvae. In contrast, the relatively large eggs and well‐developed larvae of non‐migratory species increase larval survival in what are often relatively harsh and unproductive freshwater habitats. Consequently, amphidromous species are likely to have a competitive advantage over their non‐migratory relatives when close to a pelagic habitat in which their larvae can grow and develop and then migrate upstream, releasing them from recruitment limitation and giving them a local reproductive advantage over their less fecund non‐migratory relatives.We argue that the persistence and distribution of both life‐history strategies across the landscape depends on the relative difference in the net reproductive return for each strategy in relation to distance from a pelagic larval habitat, as mediated by the relative costs of migration and egg size/fecundity relationships.
Biodiversity in heavily modified waterbodies: native and introduced fish in Iberian reservoirs
Authors: Clavero Miguel , Hermoso Virgilio , Aparicio Enric , Godinho Francisco N. 
Published: February 2013

Summary

Introduced species often thrive in modified systems, although it is not clear whether they have negative effects on native biota that might also be present or, alternatively, occupy niches that have been left empty due to the original habitat modification.

We used 247 surveys of fish assemblages (48 species in all) in riverine reservoirs across the Iberian Peninsula to analyse the relationships between the species richness of introduced and native fish. Most of the samples (195) were from areas with a Mediterranean climate, while the reminder (52) had a temperate climate.

Mediterranean reservoirs had more introduced than native species, with an opposite pattern in the temperate areas. The richness of non‐natives was positively related to the area of reservoir and human pressures and negatively related to altitude. Native richness was higher in larger and deeper reservoirs and lower in older and more impacted reservoirs, as well as in those with more introduced piscivores.

There was a negative relationship between the richness of native fish and that of non‐native piscivores in Mediterranean reservoirs, confirmed through multiple regression and structural equation modelling. Contrastingly, native fish richness was mainly controlled by variables related to water quality in temperate areas, implying that the negative impacts of introduced fishes in reservoirs can be context dependent.

The presence of introduced piscivores thus seems an important factor excluding many native fish from reservoirs in Mediterranean environments in the Iberian Peninsula.
Climate change reduces the net sink of CH4 and N2O in a semiarid grassland
Authors: Dijkstra Feike A. , Morgan Jack A. , Follett Ronald F. , LeCain Daniel R. 
Published: February 2013

AbstractAtmospheric concentrations of methane (CH4) and nitrous oxide (N2O) have increased over the last 150 years because of human activity. Soils are important sources and sinks of both potent greenhouse gases where their production and consumption are largely regulated by biological processes. Climate change could alter these processes thereby affecting both rate and direction of their exchange with the atmosphere. We examined how a rise in atmospheric CO2 and temperature affected CH4 and N2O fluxes in a well‐drained upland soil (volumetric water content ranging between 6% and 23%) in a semiarid grassland during five growing seasons. We hypothesized that responses of CH4 and N2O fluxes to elevated CO2 and warming would be driven primarily by treatment effects on soil moisture. Previously we showed that elevated CO2 increased and warming decreased soil moisture in this grassland. We therefore expected that elevated CO2 and warming would have opposing effects on CH4 and N2O fluxes. Methane was taken up throughout the growing season in all 5 years. A bell‐shaped relationship was observed with soil moisture with highest CH4 uptake at intermediate soil moisture. Both N2O emission and uptake occurred at our site with some years showing cumulative N2O emission and other years showing cumulative N2O uptake. Nitrous oxide exchange switched from net uptake to net emission with increasing soil moisture. In contrast to our hypothesis, both elevated CO2 and warming reduced the sink of CH4 and N2O expressed in CO2 equivalents (across 5 years by 7% and 11% for elevated CO2 and warming respectively) suggesting that soil moisture changes were not solely responsible for this reduction. We conclude that in a future climate this semiarid grassland may become a smaller sink for atmospheric CH4 and N2O expressed in CO2‐equivalents.
Vulnerability of terrestrial island vertebrates to projected sea‐level rise
Authors: Wetzel Florian T. , Beissmann Helmut , Penn Dustin J. , Jetz Walter 
Published: February 2013

AbstractSea‐level rise (SLR) from global warming may have severe consequences for biodiversity; however, a baseline, broad‐scale assessment of the potential consequences of SLR for island biodiversity is lacking. Here, we quantify area loss for over 12 900 islands and over 3000 terrestrial vertebrates in the Pacific and Southeast Asia under three different SLR scenarios (1 m, 3 m and 6 m). We used very fine‐grained elevation information, which offered >100 times greater spatial detail than previous analyses and allowed us to evaluate thousands of hitherto not assessed small islands. Depending on the SLR scenario, we estimate that 15–62% of islands in our study region will be completely inundated and 19–24% will lose 50–99% of their area. Overall, we project that between 1% and 9% of the total island area in our study region may be lost. We find that Pacific species are 2–3 times more vulnerable than those in the Indomalayan or Australasian region and risk losing 4–22% of range area (1–6 m SLR). Species already listed as threatened by IUCN are particularly vulnerable compared with non‐threatened species. Under a simple area loss–species loss proportionality assumption, we estimate that 37 island group endemic species in this region risk complete inundation of their current global distribution in the 1 m SLR scenario that is widely anticipated for this century (and 118 species under 3 m SLR). Our analysis provides a first, broad‐scale estimate of the potential consequences of SLR for island biodiversity and our findings confirm that islands are extremely vulnerable to sea‐level rise even within this century.
Comparison of p40 (ΔNp63) and p63 expression in prostate tissues – which one is the superior diagnostic marker for basal cells?
Authors: Sailer Verena , Stephan Carsten , Wernert Nicolas , Perner Sven , Jung Klaus , Dietel Manfred , Kristiansen Glen 
Published: February 2013

Aimsp63 is one of the standard markers for basal cells of the prostate gland. Recently, it has been suggested that the p63 isoform p40 might be more specific as a basal cell marker. In this study we compare the staining characteristics of p63 and p40 in normal and malignant prostate tissues.Methods and resultsA prostatectomy cohort (n = 640) in tissue microarray format was evaluated for p63 (clone 4A4) and for p40 (rabbit polyclonal) immunoreactivity in malignant and normal tissues. Immunoreactivity of basal and secretory cells was evaluated in a semiquantitative manner and compared case‐wise. In normal tissues, p40 showed highly similar immunoreactivity compared to p63. The staining patterns were absolutely identical in 88% of cases. Additional cytoplasmic p40 staining in tumour cells occurred in 59.6% of cancer cases. Differences were seen in nuclear staining of carcinomas: 1.4% of carcinomas were p63‐positive, whereas 0.6% were p40‐positive.ConclusionsIn most cases, p40 stains prostatic basal cells as reliably as p63, with only minor differences. Aberrant staining of tumour cells is seen more rarely than with p63 (clone 4A4), establishing its higher specificity. However, additional cytoplasmic immunoreactivity narrows its eligibility for antibody cocktails (e.g. with alpha‐methylacyl‐CoA racemase).