bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of climate‐induced increases in summer drought on riparian plant species: a meta‐analysis
Authors: Garssen Annemarie G. , Verhoeven Jos T. A. , Soons Merel B. 
Published: February 2014

Summary

Frequency and duration of summer droughts are predicted to increase in the near future in many parts of the world, with considerable anticipated effects on riparian plant community composition and species richness. Riparian plant communities along lowland streams are characterised by high species richness due to their system‐specific environmental gradients. As these streams and their hydrological gradients are mainly rain‐fed, they are sensitive to precipitation changes.

We conducted a literature survey and meta‐analysis to examine the effects of an increase in summer drought on: (i) riparian plant biomass; (ii) riparian seedling survival and (iii) riparian plant species composition and richness. We also aimed to determine whether hydrological thresholds related to drought tolerance can be distinguished for riparian plant species.

ISI Web of Knowledge was searched for relevant peer‐reviewed studies, and 23 papers were found that met our criteria and contained quantitative study results. To detect overall responses of biomass and seedling survival, a random‐effects model was applied using Comprehensive Meta‐analysis™ software. Regression curves were then fitted to response ratio data relating the effects on drought‐impacted groups to those on control groups.

Our results showed that a drought duration of approximately >30 days strongly reduces riparian plant biomass and that a duration of approximately >30–35 days and high drought intensities (starting from 3 to 4 cm water table decline per day) can be detrimental for riparian seedling survival. Especially Populus and Salix seedlings showed a reduced survival in response to drought, in contrast to Tamarix seedlings, which have the ability to rapidly and expansively elongate their roots. The data also revealed that an increase in drought conditions rapidly leads to a decline of riparian species richness and an increased presence of species adjusted to drier conditions.

Riparian groundwater level, surface water permanence and certain plant traits, especially plasticity in rooting depth, were mentioned most frequently as factors determining species responses. Very few studies mentioned hydrological thresholds, such as critical values for ground‐ and/or surface water levels, and so far these results have proved difficult to generalise.

Our meta‐analysis has shown that the projected increase in the duration and intensity of drought periods, especially intense droughts lasting more than 30 days, can be expected to narrow the riparian wetland zone with typical hydric species and accelerate riparian wetland species losses in the near future. This may require extra efforts in terms of management and restoration of species‐rich riparian areas.
Earlier and warmer springs increase cyanobacterial (Microcystis spp.) blooms in subtropical Lake Taihu, China
Authors: Deng Jianming , Qin Boqiang , Paerl Hans W. , Zhang Yunlin , Ma Jianrong , Chen Yuwei 
Published: February 2014

Summary

We examined the effects of regional warming and water quality on phytoplankton community succession, focussing on the bloom‐forming cyanobacterial genus Microcystis in subtropical Lake Taihu, China. Daily air temperatures from 1991 to 2010 indicated that onset of the Microcystis growing season has advanced by approximately 20 days over the last two decades, and accumulated air temperature (from 1 March to 31 May) has increased significantly.

Since 2005, Microcystis blooms have begun in May more frequently than in June. An increase in degree days for growth indicated that the early warming trend in spring would have benefitted Microcystis populations that overwintered on the sediment surface, by allowing them to grow, gain buoyancy and float into water column earlier in the year.

Results of canonical correspondence analysis showed that both water quality (i.e. nutrient loading) and water temperature have affected phytoplankton community succession in spring over the past two decades. When nutrient concentrations are adequate to support Microcystis blooms, rising temperature promotes their earlier onset and proliferation, a phenomenon previously documented for temperate regions, and now demonstrated for this subtropical lake.
Niche differentiation among invasive crayfish and their impacts on ecosystem structure and functioning
Authors: Jackson Michelle C. , Jones Tabitha , Milligan Maaike , Sheath Danny , Taylor Jeff , Ellis Adam , England Judy , Grey Jonathan 
Published: February 2014

Summary

Many aquatic ecosystems sustain multiple invasive species and interactions among them have important implications for ecosystem structure and functioning. Here, we examine interactions among two pairs of invasive crayfish species because of their close proximity and thus chance of sympatric populations in the near future within the Thames catchment, U.K. (signal, Pacifastacus leniusculus and virile crayfish, Orconectes virilis within a river system; red swamp, Procambarus clarkii and Turkish crayfish, Astacus leptodactylus found within a suite of ponds). We address two questions: do sympatric invasive crayfish occupy a smaller niche than their allopatric counterparts due to potential resource competition? and do interactions among invasive species amplify or mitigate one another's impacts on the ecosystem?

Two fully factorial mesocosm experiments (one for each crayfish pair) were used to investigate crayfish diet and their impact on benthic invertebrate community structure, benthic algal standing stock and leaf litter decomposition rates in allopatric and sympatric populations, compared with a crayfish‐free control. We used stable isotope analysis to examine crayfish diet in the mesocosms and in allopatric populations of each species in the Thames catchment.

Isotopic niche width did not vary significantly between allopatric and sympatric populations of crayfish in the mesocosm experiments, and isotopic niche partitioning in all the wild populations suggests the invaders can coexist.

All four species altered benthic invertebrate community structure but with differing functional effects, often mediated via trophic cascades. Red swamp crayfish predation upon snails evidently promoted benthic algal standing stock via reduction in grazing pressure. However, a trophic cascade whereby the crayfish consumed native invertebrate shredders, causing a reduction in net leaf litter decomposition, was decoupled by red swamp and signal crayfish since they consumed leaf litter directly and thus moderated the cascade to a trickle when in sympatry with Turkish or virile crayfish, respectively.

Benthic invertebrate predator abundance was significantly reduced by sympatric red swamp and Turkish crayfish but not independently when in allopatry, indicating an amplified effect overall when in sympatry.

Our results suggest that the combined effect of multiple invasions on the ecosystem can reflect either an additive effect of their independent impacts or an amplified effect, which is greater than the sum of their independent impacts. A lack of general pattern in their effects makes any potential management strategy more complex.
Productivity, 15N dynamics and water use efficiency in low‐ and high‐input switchgrass systems
Authors: Pedroso Gabriel M. , van Kessel Chris , Six Johan , Putnam Daniel H. , Linquist Bruce A. 
Published: February 2014

AbstractSustainable and environmentally benign switchgrass production systems need to be developed for switchgrass to become a large‐scale dedicated energy crop. An experiment was conducted in California from 2009 to 2011 to determine the sustainability of low‐ and high‐input irrigated switchgrass systems as a function of yield, irrigation requirement, crop N removal, N translocation from aboveground (AG) to belowground (BG) biomass during senescence, and fertilizer 15N recovery (FNR) in the AG and BG biomass (0–300 cm), and soil (0–300 cm). The low‐input system consisted of a single‐harvest (mid‐fall) irrigated until flowering (early summer), while the high‐input system consisted of a two‐harvest system (early summer and mid‐fall) irrigated throughout the growing season. Three N fertilization rates (0, 100, and 200 kg N ha−1 yr−1) were applied as subtreatments in a single application in the spring of each year. A single pulse of 15N enriched fertilizer was applied in the first year of the study to micro‐plots within the 100 kg N ha−1 subplots. Average yields across years under optimal N rates (100 and 200 kg ha−1 yr−1 for low‐ and high‐input systems, respectively) were 20.7 and 24.8 Mg ha−1. However, the low input (372 ha mm) required 47% less irrigation than the high‐input system (705 ha mm) and achieved higher irrigation use efficiency. In addition, the low‐input system had 46% lower crop N removal, 53% higher N stored in BG biomass, and a positive N balance, presumably due to 49% of 15N translocation from AG to BG biomass during senescence. Furthermore, at the end of 3 years, the low‐input system had lower fertilizer 15N removed by harvest (26%) and higher FNR remaining in the system in BG biomass plus soil (31%) than the high‐input system (45% and 21%, respectively). Based on these findings, low‐input systems are more sustainable than high‐input systems in irrigated Mediterranean climates.
Cost‐benefit analysis of using biochar to improve cereals agriculture
Authors: Dickinson Dane , Balduccio Ludovico , Buysse Jeroen , Ronsse Frederik , van Huylenbroeck Guido , Prins Wolter 
Published: February 2014

AbstractBiochar has received considerable scientific attention in the past decade as a possible method for carbon storage and increasing agricultural yields. Despite this promise, however, economic assessments of biochar are yet to definitively establish the value of the technology, primarily due to discrepancy between observed short‐term agronomic benefits and expectations of biochar as a lasting soil improver. This study investigated the economic value of biochar as an agricultural technology for long‐term improvement of arable farming. From presently available field trial data, the costs and benefits of using biochar technology to enhance cereals agriculture were evaluated in two generalized geo‐economic agricultural scenarios: North‐Western Europe (NWE) and Sub‐Saharan Africa (SSA). Cost models were developed to estimate the total cost of biochar from initial biomass feedstock acquisition to final soil application for each agricultural setting. Benefits of biochar application were estimated by statistical meta‐analysis of crop yield data from published biochar field trials to find the increase in cereal grain yield attributable to biochar application for both NWE (+0.07 to +0.28 t ha−1 yr−1) and SSA (+0.18 to +1.00 t ha−1 yr−1). The grain yield improvement from a one‐time biochar application was assumed to persist without decay for an independently varying time period, and the increase in grain production then monetised using projected future commodity prices. The Net Present Value (NPV) of applying biochar was then calculated by setting present total costs against present total benefits as a function of biochar performance longevity. Biochar application was found to carry a positive NPV for cereal cropping in SSA in several scenarios where the duration of the biochar yield effect was assumed to extend 30 years into the future. Conversely, NWE biochar scenarios were all found to have negative NPVs even when the benefits time span was indefinitely stretched.
Explaining European Emission Allowance Price Dynamics: Evidence from Phase II
Authors: Rickels Wilfried , Görlich Dennis , Peterson Sonja 
Published: February 2014

AbstractWe empirically investigate potential determinants of the allowance price dynamics in the European Union Emission Trading Scheme during Phase II. In contrast to previous studies, we place particular emphasis on the fuel price selection. We show that results are extremely sensitive to choosing different price series of potential determinants, such as coal and gas prices. In general, only the influence of economic activity in Europe and hydropower provision in Norway is robustly explaining allowance price dynamics. The influence of fuel switching on allowance prices and, therefore, equalization of marginal abatement costs - in particular in the long run - is still rather small.
Seasonal carbon dynamics and the effects of manure application on carbon budget of a managed grassland in a temperate, humid region in Japan
Authors: Matsuura Shoji , Miyata Akira , Mano Masayoshi , Hojito Masayuki , Mori Akinori , Kano Shunpei , Sasaki Hiroyuki , Kohyama Kazunori , Hatano Ryusuke 
Published: February 2014

AbstractWe conducted a field experiment from 2004 to 2007 in a temperate, humid region in Japan to investigate seasonal carbon dynamics and their interaction with vegetation. We also examined the effect of composted livestock manure application on the carbon budget in an intensively managed grassland. Two experimental plots were established for the study: one receiving only chemical fertilizer and the other receiving composted cattle manure and supplementary chemical fertilizer. Carbon dioxide flux was measured continuously using the eddy covariance technique, and net ecosystem production (NEP) and net biome production (NBP) were evaluated. We found that the seasonal variations of carbon dynamics were affected not only by climatic conditions but also by vegetation. NEP during the first crop increased rapidly to a high value, which resulted in positive cumulative NEP. In contrast, cumulative NEP during the second to the fourth crop and during winter was only slightly positive or even negative. Thus, NEP during the first crop made a significant contribution to annual NEP. It also occupied an important place in annual NBP via carbon stock into the belowground biomass. The different fertilization regimes between the plots resulted in no significant differences in harvest or NEP on an annual basis. However, the chemically fertilized grassland plot lost carbon, whereas the plot receiving composted cattle manure and supplementary chemical fertilizer accumulated carbon. These results suggest that manure application results in sustainable grassland management enhancing carbon sequestration.
Geographic disparities in arteriovenous fistula placement in patients approaching hemodialysis in the United States
Authors: Goldfarb‐Rumyantzev Alexander S. , Syed Wajih , Patibandla Bhanu K. , Narra Akshita , Desilva Ranil , Chawla Varun , Hod Tammy , Vin Yael 
Published: February 2014

AbstractArteriovenous fistula (AVF) is the preferred vascular access for hemodialysis (HD). Several factors associated with AVF placement have been identified (e.g., age, sex, race, comorbidities). We hypothesized that geographic location of patient residence might be associated with the probability of AVF placement as the initial access. We used the data from the United States Renal Data System (USRDS) database (2005–2008) linked to Medicare claims (2003–2008). Logistic regression was used to estimate specific characteristics of population associated with the AVF as first access placed or attempted for HD initiation. Our primary variable of interest was the geographic location, and the multivariate model was adjusted for age, sex, race, body mass index, primary cause of end‐stage renal disease (ESRD), duration of pre‐ESRD nephrology care, comorbidities, employment status, substance abuse, and income. Geographic location was determined using the data collected by the RUCA project and divided population into metropolitan, micropolitan, and rural categories. Patients (n = 111,953) identified from the USRDS database with linked Medicare claims were examined. Rates of fistula placement in the metropolitan, micropolitan, and rural population were 18.5%, 22.4%, and 21.6%, respectively. In comparison, patients who received catheter as the first access were 81.5%, 77.6% and 78.4%, respectively. The odds ratio of AVF placement as a first HD access in the rural and metropolitan population compared with the micropolitan population were 0.96 (0.90–1.03; P = 0.26) and 0.80 (0.76–0.84; P < 0.001), respectively. Our results indicate the presence of geographic disparities in AVF placement with decreased rates of AVF as the first access created in the metropolitan (but not rural) populations compared with the micropolitan communities.
Clinical outcome of intentional replantation with preoperative orthodontic extrusion: a retrospective study
Authors: Choi Y. H. , Bae J. H. , Kim Y. K. , Kim H. Y. , Kim S. K. , Cho B. H. 
Published: February 2014

AbstractAimTo evaluate retrospectively the clinical outcomes of intentional replantation (IR) of teeth in terms of tooth survival and periradicular healing and to investigate their prognostic factors.MethodologyTwo hundred and eighty‐seven teeth treated by IR were analysed retrospectively. Clinical outcomes between the cases with preoperative orthodontic extrusion for 2–3 week and those without extrusion were analysed. The outcomes of IR were determined by clinical and radiographic evaluation. Tooth survival and periradicular healing estimates were compared using Kaplan–Meier analysis. The contribution of a patient's age and gender, tooth type and location, and preoperative orthodontic extrusion was investigated using the multivariate Cox proportional hazard model.ResultsThe mean follow‐up period was 25.4 ± 9.3 months. The overall success rate of IR was 89.5% based on periradicular healing. The overall survival rate was 95.1%. The survival rates were 91.2% for the teeth extracted without extrusion and 98.1% for those extracted with extrusion. Amongst the variables tested, only the extraction technique with preoperative orthodontic extrusion significantly affected the survival rate (P = 0.016). Other prognostic variables, such as age and gender, tooth type and location, did not affect the survival of intentionally replanted teeth.ConclusionsIntentional replantation was a viable treatment option for teeth with previously failed nonsurgical root canal treatment, regardless of a patient's age and gender, and tooth type and location. Preoperative orthodontic extrusion for 2–3 weeks reduced root resorption and tooth fracture and can be recommended to enhance the outcome of IR.
Ultra‐High‐Temperature Ceramic HfB2‐SiC Coating for Oxidation Protection of SiC‐Coated Carbon/Carbon Composites
Authors: Ren Xuanru , Li Hejun , Chu Yanhui , Fu Qiangang , Li Kezhi 
Published: February 2014

To protect the carbon/carbon (C/C) composites from oxidation, an outer ultra‐high‐temperature ceramics (UHTCs) HfB2‐SiC coating was prepared on SiC‐coated C/C composites by in situ reaction method. The outer HfB2‐SiC coating consists of HfB2 and SiC, which are synchronously obtained. During the heat treatment process, the formed fluid silicon melt is responsible for the preparation of the outer HfB2‐SiC coating. The HfB2‐SiC/SiC coating could protect the C/C from oxidation for 265 h with only 0.41 × 10−2 g/cm2 weight loss at 1773 K in air. During the oxidation process, SiO2 glass and HfO2 are generated. SiO2 glass has a self‐sealing ability, which can cover the defects in the coating, thus blocking the penetration of oxygen and providing an effective protection for the C/C substrate. In addition, SiO2 glass can react with the formed HfO2, thus forming the HfSiO4 phase. Owing to the “pinning effect” of HfSiO4 phase, crack deflecting and crack termination are occurred, which will prevent the spread of cracks and effectively improve the oxidation resistance of the coating.
Lack of IgG antibody seropositivity to Borrelia burgdorferi in patients with Parry–Romberg syndrome and linear morphea en coup de sabre in Mexico
Authors: Gutiérrez‐Gómez Claudia , Godínez‐Hana Ana L. , García‐Hernández Marisela , Suárez‐Roa María de Lourdes , Toussaint‐Caire Sonia , Vega‐Memije Elisa , Gutiérrez‐Mendoza Daniela , Pérez‐Dosal Marcia , Medina‐De la Garza Carlos E. 
Published: February 2014

AbstractBackgroundProgressive hemifacial atrophy or Parry–Romberg Syndrome (PRS) is a rare, acquired, progressive dysplasia of subcutaneous tissue and bone characterized by unilateral facial involvement. Its etiology is unknown, but theories about its pathogenesis include infectious, degenerative, autoimmune, and traumatic causes among others. The causal relationship of PRS and linear morphea en coup de sabre (LMCS) with Borrelia burgdorferi infection remains controversial. Our goal was to serologically determine anti‐B. burgdorferi antibodies in patients diagnosed with PRS and LMCS to establish a possible association as a causative agent.MethodsWe conducted a serology study with patients belonging to a group of 21 individuals diagnosed with PRS, six with LMCS, and 21 matched controls. Anti‐Borrelia IgG antibodies were determined by ELISA. A descriptive statistical analysis and Fischer's exact test were done.ResultsIn serological tests, only two cases had borderline values and were further analyzed by Western blot with non‐confirmatory results. For both the PRS and LMCS group, the association test was not significant, suggesting a lack of association between PRS or LMCS and the presence of anti‐Borrelia antibodies.ConclusionIn Mexico there are no previous studies on Borrelia infection and its relationship between PRS or LMCS. Our result showed a lack of association of either clinical entities with anti‐Borrelia‐antibodies. Former reports of this association may suggest coincidental findings without causal relationship.
Assessment of tissue FoxP3+, CD4+ and CD8+ T‐cells in active and stable nonsegmental vitiligo
Authors: Abdallah Marwa , Lotfi Ranya , Othman Wessam , Galal Riham 
Published: February 2014

AbstractBackgroundThe exact etiology of vitiligo remains obscure. Studies have indicated a role for cellular immunity in the pathogenesis of vitiligo. The aim of this study is to assess tissue FoxP3+ natural regulatory T‐cells (Tregs), as well as CD4+ and CD8+ T‐cells in active vs. stable nonsegmental vitiligo.Materials and methodsImmunohistochemical double‐staining for expression of CD4+ and CD8+ T‐cells with immunostaining for expression of FoxP3 in lesional, marginal, and nonlesional skin of nonsegmental vitiligo was used to evaluate the abundance of Tregs among CD4+ and CD8+ T‐cells in active and stable cases of vitiligo.ResultsA significant increase in the number of CD4+ and CD8+ T‐cells and a highly significant reduction in the number of FoxP3‐expressing Tregs were detected in marginal skin in both stable and active vitiligo cases. FoxP3+ cells were decreased in tissue of patients with vitiligo compared with healthy controls. The number of CD8+ T‐cells was increased in the epidermis and dermoepidermal junction (DEJ) in comparison with the number of CD4+ T‐cells. Tregs were mostly present at the DEJ.ConclusionThe reduction in the number of FoxP3+ cells in the marginal skin suggests that this is the site where regulatory activity is needed to suppress the activity of helper and cytotoxic T‐cells that are actively contributing to depigmentation.