bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of hydraulics on the uptake of ammonium by two freshwater plants
Authors: Bal Kris D. , Brion Natacha , Woulé‐Ebongué Veronique , Schoelynck Jonas , Jooste Antoinette , Barrón Cristina , Dehairs Frank , Meire Patrick , Bouma Tjeerd J. 
Published: August 2013

Summary

Macrophytes are important in the biogeochemistry of flowing rivers, although most information so far has relied on measurements of nutrients in plant tissues. This yields only indirect information on the nutrient uptake fluxes by roots and shoots and about nutrient translocation between roots and shoots. Here, we studied nitrogen uptake through experiments with enriched 15N stable isotopes.

Two macrophytes (Potamogeton natans and Ranunculus fluitans) were grown in a closed race track‐shaped flume, allowing us to control the hydraulic conditions in and around the plants. Overall ammonium uptake rates (μmol g−1 dry mass h−1) were higher for R. fluitans than P. natans.

In addition to differences between the species, the spatial position of individuals within the plant patch and water flow were also important in explaining ammonium uptake. Thus, ammonium uptake was high at the leading edge of the patch and increased with velocity.

Plant characteristic, such as the angle at which the plants bent in the flow, was also correlated with ammonium uptake. Differences in nutrient uptake associated with hydrodynamic parameters raised the question of how the two are related. For both species, uptake was not correlated with Reynolds stress, indicating the poor effect of turbulent mixing in determining ammonium uptake.
Climate change and trophic interactions in model temporary pond systems: the effects of high temperature on predation rate depend on prey size and density
Authors: Ewald Naomi C. , Hartley Sue E. , Stewart Alan J. A. 
Published: August 2013

Summary

Climatic warming has induced marked shifts in the geographical distribution and seasonal phenology of many species, although the impacts of climatic changes on the interactions between species across trophic levels are far less well known.

Freshwater microcosms were used to test the effect of temperature on the life history traits of a prey species, the fairy shrimp Chirocephalus diaphanus (Anostraca), the abundance of a predator, the microcrustacean Heterocypris incongruens (Ostracoda), and on the interaction between them.

When reared in the absence of predators, C. diaphanus survival was low at the highest temperature (25 °C) and greatly reduced at the lowest temperature (5 °C). It was reproductively most successful at an intermediate temperature (20 °C), suggesting that it may benefit from the increase in temperature predicted under future climate change scenarios. In the absence of other species, temperature would have to increase dramatically to affect C. diaphanus adversely.

Heterocypris incongruens was more abundant and its predation on C. diaphanus greatest at higher temperatures, partially offsetting the positive effect of raised temperature on prey observed when the predator was absent. The net effect was that the optimal temperature for C. diaphanus when coexisting with its predator was lower than when it was in isolation. This means that currently predicted increases in temperature ultimately may be detrimental to C. diaphanus.

Predation rates were generally enhanced by high temperature, prey size and prey density, with significant interaction between them. Thus, the positive effects of raised temperature on predation rate were additionally dependent upon prey characteristics, being strongest when prey were large and at high density and weakest when prey were small and at low density.

Interactions with a natural enemy, in this case a predator, may alter how species respond to raised temperatures; prey size and density further modify the outcome of this interaction. This context dependency in the response of both predators and prey to temperature suggests that the ecological impacts of future climate change on trophic interactions may be difficult to predict.
The influence of native replanting on stream ecosystem metabolism in a degraded landscape: can a little vegetation go a long way?
Authors: Giling Darren P. , Grace Michael R. , Mac Nally Ralph , Thompson Ross M. 
Published: August 2013

Summary

The effectiveness of revegetation is usually gauged by responses in biodiversity, which may differ between isolated replanted patches. The ecological value of revegetation may be detected more effectively by monitoring ecosystem processes. In‐stream metabolism has been much modified by the degradation of riparian vegetation in agricultural landscapes around the world. We sought to determine whether the spatial scale typical of most riparian replanting projects (i.e. <1 km long) influences stream metabolism.

Metabolism is a functional measure that incorporates gross primary production (GPP), ecosystem respiration (ER) and the difference between them [net ecosystem productivity (NEP)]. We hypothesised that replanted reaches would have lower GPP (due to greater canopy shading) and greater ER (governed by larger terrestrial energy inputs) compared with pasture reaches.

We measured metabolism in paired reaches within four agricultural streams. Two streams had an untreated pasture reach contrasted with a reach replanted with native woody vegetation >17 years ago. The other two streams had similar riparian vegetation condition adjacent to both reaches, to act as reference sites.

Mean daily GPP (0.27–4.9 g O2 m−2 day−1) and ER (1.1–22 g O2 m−2 day−1) were within the range of values recorded previously in agricultural streams elsewhere. Replanted reaches had rates of NEP lower than upstream untreated reaches at treatment sites, but NEP was similar between reaches at reference sites.

The effects of replanting on stream ecosystem processes are detectable even when the spatial scale of restoration is relatively small in a whole‐of‐catchment context. Land managers can protect and restore vegetation at feasible spatial scales and benefit ecosystem processes. Ecosystem metabolism should be included in the range of responses that need to be monitored to provide a complete picture of the effectiveness of stream restoration.
Long‐term changes in hypoxia and soluble reactive phosphorus in the hypolimnion of a large temperate lake: consequences of a climate regime shift
Authors: North Ryan P. , North Rebecca L. , Livingstone David M. , Köster Oliver , Kipfer Rolf 
Published: August 2013

AbstractThe (Lower) Lake of Zurich provides an ideal system for studying the long‐term impact of environmental change on deep‐water hypoxia because of its sensitivity to climatic forcing, its history of eutrophication and subsequent oligotrophication, and the quality and length of its data set. Based on 39 years (1972–2010) of measured profiles of temperature, oxygen concentration and phosphorus (P) concentration, the potentially confounding effects of oligotrophication and climatic forcing on the occurrence and extent of deep‐water hypoxia in the lake were investigated. The time‐series of Nürnberg's hypoxic factor (HF) for the lake can be divided into three distinct segments: (i) a segment of consistently low HF from 1972 to the late‐1980s climate regime shift (CRS); (ii) a transitional segment between the late‐1980s CRS and approximately 2000 within which the HF was highly variable; and (iii) a segment of consistently high HF thereafter. The increase in hypoxia during the study period was not a consequence of a change in trophic status, as the lake underwent oligotrophication as a result of reduced external P loading during this time. Instead, wavelet analysis suggests that changes in the lake's mixing regime, initiated by the late‐1980s CRS, ultimately led to a delayed but abrupt decrease in the deep‐water oxygen concentration, resulting in a general expansion of the hypoxic zone in autumn. Even after detrending to remove long‐term effects, the concentration of soluble reactive P in the bottom water of the lake was highly correlated with various measures of hypoxia, providing quantitative evidence supporting the probable effect of hypoxia on internal P loading. Such climate‐induced, ecosystem‐scale changes, which may result in undesirable effects such as a decline in water quality and a reduction in coldwater fish habitats, provide further evidence for the vulnerability of large temperate lakes to predicted increases in global air temperature.
Investigating Groundwater Flow Between Edwards and Trinity Aquifers in Central Texas
Authors: Wong C.I. , Kromann J.S. , Hunt B.B. , Smith B.A. , Banner J.L. 
Published: August 2013

AbstractUnderstanding the nature of communication between aquifers can be challenging when using traditional physical and geochemical groundwater sampling approaches. This study uses two multiport wells completed within Edwards and Trinity aquifers in central Texas to determine the degree of groundwater inter‐flow between adjacent aquifers. Potentiometric surfaces, hydraulic conductivities, and groundwater major ion concentrations and Sr isotope values were measured from multiple zones within three hydrostratigraphic units (Edwards and Upper and Middle Trinity aquifers). Physical and geochemical data from the multiport wells were combined with historical measurements of groundwater levels and geochemical compositions from the region to characterize groundwater flow and identify controls on the geochemical compositions of the Edwards and Trinity aquifers. Our results suggest that vertical groundwater flow between Edwards and Middle Trinity aquifers is likely limited by low permeability, evaporite‐rich units within the Upper and Middle Trinity. Potentiometric surface levels in both aquifers vary with changes in wet vs. dry conditions, indicating that recharge to both aquifers occurs through distinct recharge areas. Geochemical compositions in the Edwards, Upper, and Middle Trinity aquifers are distinct and likely reflect groundwater interaction with different lithologies (e.g., carbonates, evaporites, and siliceous sediments) as opposed to mixing of groundwater between the aquifers. These results have implications for the management of these aquifers as they indicate that, under current conditions, pumping of either aquifer will likely not induce vertical cross‐formational flow between the aquifers. Inter‐flow between the Trinity and the Edwards aquifers, however, should be reevaluated as pumping patterns and hydrogeologic conditions change.
Catheter‐free discharge on first postoperative day after bipolar transurethral resection of prostate: Clinical outcomes of 100 cases
Authors: Shum Cheuk Fan , Mukherjee Amit , Teo Chang Peng Colin 
Published: August 2013

ObjectivesOur center has adopted a protocol for catheter‐free first postoperative day discharge after bipolar transurethral resection of the prostate. We present the immediate, 1‐month and 6‐month outcomes of our first 100 cases following this protocol.MethodsAll bipolar transurethral resection of the prostate patients followed the protocol regardless of indications and background comorbid conditions. Bladder irrigation was stopped in the evening after transurethral resection of the prostate, and the catheter was removed at 06.00 hours. All patients were discharged on the first postoperative day. They were reviewed at 1 month and 6 months with the International Prostate Symptom Score and uroflowmetry.ResultsThe mean age of the study population was 70.8 years. A total of 40 patients had urinary retention and were on an indwelling catheter before transurethral resection of the prostate. A total of 14 patients had other surgeries in the same setting as the transurethral resection of the prostate. The mean resection weight was 32.7 g. The mean irrigation time and catheter time were 4.2 h and 15.0 h, respectively. The improvement in terms of International Prostate Symptom Score, quality of life score, peak flow rate and post‐void residual volume was comparable with those reported in the literature for bipolar transurethral resection of the prostate. Similarly, early and late complication rates also compared favorably with the literature. The perioperative cost was significantly reduced.ConclusionsCatheter‐free first postoperative day discharge after bipolar transurethral resection of the prostate is safe with good clinical outcomes and cost savings.
Observation charts with overlapping blood pressure and heart rate graphs do not yield the performance advantage that health professionals assume: an experimental study
Authors: Christofidis Melany J. , Hill Andrew , Horswill Mark S. , Watson Marcus O. 
Published: August 2013

AbstractAimTo investigate whether overlapping blood pressure and heart rate graphs improve chart‐users' ability to recognize derangements in these vital signs on hospital observation charts.BackgroundMany health professionals prefer blood pressure and heart rate graphs to overlap. One justification is the use of a visual cue called the ‘Seagull Sign’ to detect physiological abnormalities.DesignA 3 × 2 × 2 mixed‐design experiment, with three independent variables: participant group, graph format (separate vs. overlapping) and alerting system (integrated colour‐based track‐and‐trigger system present vs. absent).MethodsOver 64 experimental trials, ‘Seagull‐trained’ nurses and novices randomly assigned to receive ‘Seagull training’ or remain untrained, viewed sequences of blood pressure and heart rate observations recorded on four different chart design extracts. The designs represented a crossing of the graph format and alerting system variables. For each design, eight cases contained normal data and eight contained an abnormal systolic blood pressure or heart rate observation (half of which yielded a Seagull Sign on overlapping plots). Participants (tested between January–May 2011) judged whether observations were physiologically normal or abnormal.ResultsAcross all cases, participants from all groups responded faster and made fewer errors when blood pressure and heart rate observations were graphed separately, especially when a track‐and‐trigger system was present. Even for ‘Seagull‐trained’ participants viewing ‘Seagull Sign available’ cases, no advantage of overlapping graphs was found.ConclusionsThese findings suggest that overlapping graphs do not yield the performance advantage that many health professionals assume, either for novices or experienced nurses, even when the Seagull Sign is used.
Range dynamics of the reindeer in Europe during the last 25,000 years
Authors: Sommer Robert S. , Kalbe Johannes , Ekström Jonas , Benecke Norbert , Liljegren Ronnie 
Published: August 2013

AbstractAimTo understand the role and significance of the reindeer, Rangifer tarandus (Linnaeus, 1758), as a specific indicator in terms of late Quaternary biogeography and to determine the effects of global climate change on its range and local extinction dynamics at the end of the Ice Age.LocationLate Pleistocene/early Holocene range of reindeer over all of central and western Europe, including southern Scandinavia and northern Iberia, but excluding Russia, Belarus and the Ukraine.MethodsRadiocarbon‐dated subfossil records of R. tarandus from both archaeological and natural deposits younger than 25,000 years were assembled in a database. The distribution area was divided into six representative regions. The 14C dates were calibrated and plotted chronologically in maps in order to compare presence and absence and regional extinction patterns from one region to another.ResultsAfter the Last Glacial Maximum, R. tarandus disappeared from south‐eastern Central Europe but survived in the south‐west until the Younger Dryas period. The ‘Allerød warming’ did not result in complete extirpation of reindeer in Central Europe. Reindeer probably disappeared c. 11,250 years ago in the North European Plain and c. 11,000 years ago in the British Isles. In southern Scandinavia the species survived until c. 10,300 years ago.Main conclusionsThe late Quaternary record for reindeer in Europe during the last 25 kyr shows a climate‐driven dispersal and retreat in response to climate change, with regional variations. The collapse of the mammoth steppe biome did not lead to the local extinction in Europe, as in the case of other megafaunal species. Rangifer tarandus co‐existed for about 3000 years during the Late Glacial and early Holocene with typical temperate species such as red deer and roe deer in non‐analogue faunal communities. The regional extinction at the end of the Pleistocene coincides with the transition from light open birch/pine forests to pine/deciduous forests.
Electrophysiological Properties of the Superior Vena Cava and Venoatrial Junction in Patients with Atrial Fibrillation
Authors: FUKUMOTO KOTARO , TAKATSUKI SEIJI , KIMURA TAKEHIRO , NISHIYAMA NOBUHIRO , TANIMOTO KOJIRO , AIZAWA YOSHIYASU , TANIMOTO YOKO , FUKUDA YUKIKO , MIYOSHI SHUNICHIRO , FUKUDA KEIICHI 
Published: August 2013

Electrophysiological Properties of the Superior Vena Cava and Venoatrial JunctionBackgroundAlthough the superior vena cava (SVC) has been well known to be one of the important foci triggering atrial fibrillation (AF), its electrophysiological characteristics have received little research attention. The aim of this study was to investigate the electrophysiological properties of the SVC and venoatrial junction (VAJ).MethodsTwenty‐five consecutive AF patients without structural heart disease undergoing electrical SVC isolation were included in this study. After pulmonary vein isolation, a circular decapolar catheter and 2 multipolar catheters were emplaced in the VAJ, right atrial appendage (RAA), and SVC, respectively. Burst pacing and single extrastimulus were applied from the RAA and SVC. The atrial and caval potentials on the circular catheter in the VAJ were investigated.ResultsIntracaval conduction delay and various degrees of conduction block over the VAJ were observed with burst pacing from both the RAA and SVC. A single extrastimulus from the RAA and SVC with a basic cycle length of 600 milliseconds prolonged the conduction time via the VAJ by 81 ± 49.7 milliseconds and 61 ± 58.7 milliseconds, respectively. The atrial and caval electrograms at the VAJ, which were separated from each other by pacing applications, facilitated mapping of the earliest activation site at the VAJ.ConclusionsIntracaval conduction delay and decremental conduction property via the VAJ were demonstrated using pacing maneuvers. Pacing applications from the RAA or SVC can help distinguish the atrial and caval potentials and can facilitate mapping of the optimal ablation sites to isolate the SVC.
Ethnic differences in oro‐facial somatosensory profiles—quantitative sensory testing in Chinese and Danes
Authors: Yang G. , Luo Y. , Baad‐Hansen L. , Wang K. , Arendt‐Nielsen L. , Xie Q.‐F. , Svensson P. 
Published: August 2013

SummaryEthnic differences in pain experiences have been widely assessed in various pathological and experimental conditions. However, limited sensory modalities have been described in previous research, and the affective‐motivational factors have so far been estimated to be the main mediator for the ethnic differences. This study aimed to detect the ethnic differences of oro‐facial somatosensory profiles related to the sensory‐discriminative dimension in healthy volunteers. The standardised quantitative sensory testing battery developed by the German Research Network on Neuropathic Pain was performed bilaterally in the infraorbital and mental regions on age‐ and gender‐matched healthy Chinese and Danes, 29 participants each group. The influences of ethnicity, gender and test site on the somatosensory profile were evaluated by three‐way anova. The ethnic disparities were also presented by Z‐scores. Compared to Danes, Chinese were more sensitive to thermal detection, thermal pain, mechanical deep pain and mechanical pain rating parameters (P < 0·002) related to small fibre functions. However, the inverse results were observed for mechanical tactile modality related to large fibre function (P < 0·001) and wind‐up ratio (P = 0·006). Women presented higher sensitivity compared to men. The mean Z‐scores of all the parameters from Chinese group were in the normal zone created by Danish Caucasians’ means and SDs. The ethnic disparities in somatosensory profile illustrated the necessity of establishing the reference data for different ethnic groups and possibly individual pain management strategies for the different ethnic groups.
Do Social Relationships Buffer the Effects of Widowhood? A Prospective Study of Adaptation to the Loss of a Spouse
Authors: Anusic Ivana , Lucas Richard E. 
Published: August 2013

AbstractThe idea that strong social relationships can buffer the negative effects of stress on well‐being has received much attention in existing literature. However, previous studies have used less than ideal research designs to test this hypothesis, making it difficult to draw firm conclusions regarding the buffering effects of social support. In this study, we examined the buffering hypothesis in the context of reaction and adaptation to widowhood in three large longitudinal datasets. We tested whether social relationships moderated reaction and adaptation to widowhood in samples of people who experienced loss of a spouse from three longitudinal datasets of nationally representative samples from Germany (N = 1,195), Great Britain (N = 562), and Australia (N = 298). We found no evidence that social relationships established before widowhood buffered either reaction or adaptation to the death of one's spouse. Similarly, social relationships that were in place during the first year of widowhood did not help widows and widowers recover from this difficult event. Social relationships acquired prior to widowhood, or those available in early stages of widowhood, do not appear to explain individual differences in adaptation to loss.
SQUATTING ON GOVERNMENT LAND
Authors: Shah Nilopa 
Published: August 2013

ABSTRACTThis paper presents an economic theory of squatter settlements in developing countries. It adds to the existing literature by explicitly modeling squatting on government‐owned land and presents a unified framework for analysis of issues related to squatting, urban planning and policy. In the model, a squatter‐organizer optimally controls squatting so as to forestall eviction. The model highlights how the existence of an eviction cost leads to formal residents tolerating squatting, trading‐off “open space” to avoid paying taxes toward evicting squatters. The paper derives comparative‐static results under some functional form assumptions. The analysis is extended to examine the comparative‐static effects for the case where squatters freely migrate into the city. The framework for exploring a combined model of squatting on government and private land is also laid out. Finally, some policy analysis of squatter formalization is carried out.