bluuebunny/crossref_metadata_2025_split huggingface dataset:
Groundwater seepage stimulates the growth of aquatic macrophytes
Authors: FRANDSEN METTE , NILSSON BERTEL , ENGESGAARD PETER , PEDERSEN OLE 
Published: March 2012

Summary1. The impact of groundwater seepage on the growth of submerged macrophytes was investigated in experiments on the isoetid Littorella uniflora and the elodeid Myriophyllum alterniflorum both in the laboratory and in the field. Isoetids rely mostly on sediment‐derived CO2 and nutrients via root uptake, whereas elodeids acquire their inorganic carbon and nutrients from the water column. We thus hypothesised that L. uniflora would respond positively to seeping ground water as it should improve both CO2 and nutrient supply.2. Laboratory experiments were conducted by percolating vegetated cores containing natural sediment or technical sand with artificial ground water of high CO2 concentrations and with either high or low levels of nutrients. Field experiments were conducted in the oligotrophic Lake Hampen, Denmark, with custom‐built seepage‐growth chambers that permitted a near‐natural flow‐through of seeping ground water. Chambers with a solid bottom, and thus no flow‐through of seeping ground water, served as controls in both laboratory and field experiments. In the field, seepage chambers were installed at a site with relatively high seepage fluxes (ground water from forest catchment), at a site with much lower seepage fluxes but with higher nutrient concentrations (ground water from agricultural catchment) and at a reference site with no net discharge or recharge of ground water.3. Positive growth responses were observed in the field at transects with high groundwater discharge compared to the control chambers with no seepage. No growth response was observed at the reference transect with low or alternating direction of groundwater seepage. The growth rates of L. uniflora in the field were significantly higher in seepage treatments compared to control treatments, and final plant mass was up to 70% higher than that for plants where seepage was excluded. In areas with high groundwater discharge, a strong positive correlation was found between groundwater seepage fluxes, growth rates, and final plant mass for L. uniflora, while there was no such relationship at the reference transect. The growth of M. alterniflorum was also significantly affected by groundwater seepage, but to a lesser degree than L. uniflora. Laboratory experiments generally showed the same trend for both L. uniflora and M. alterniflorum, and the positive influence of seeping ground water was apparently related to increased inorganic carbon supply and, to a lesser degree, improved nutrient availability.4. Groundwater discharge results in enhanced growth of isoetids and to some extent elodeids inhabiting a groundwater‐fed softwater lake. We propose that the shallow dense vegetation present where most of the discharge takes place acts as a biological filter that retains nutrients that otherwise would end up in the water column and could result in increased algal growth.
Managing the impacts of nutrient enrichment on river systems: dealing with complex uncertainties in risk analyses
Authors: PAGE T. , HEATHWAITE A. L. , MOSS B. , REYNOLDS C. , BEVEN K. J. , POPE L. , WILLOWS R. 
Published: March 2012

Summary1. Rivers and their catchments are complex, dynamic and non‐equilibrium systems. Although the general functioning of these ecosystems is familiar, the characteristics of particular sites are often poorly known and accurate prediction of future behaviour to inform management decisions is extremely difficult.2. Simple relationships between river nutrient concentrations and the health of river ecosystems do not exist. Natural variability and practical and technical constraints reduce our ability to set nutrient targets to protect river ecosystems. Particularly challenging is the use of simple dose–response relationships as regulatory threshold targets, whereby sections of river are classified as either passing or failing to meet good ecological status.3. Ecologically meaningful frameworks are needed that take account of the epistemic uncertainty associated with our predictions. Such frameworks should have clearly defined goals; be holistic; allow for natural variability; help to define ecologically acceptable environmental regimes; recognise that significant uncertainties mean that we will often be using indices rather than absolute measures; and use measures that explicitly include uncertainty estimates. Such approaches allow those outside the decision‐making process to understand the level of environmental precaution included in the management of complex systems.
How river structure and biological traits influence gene flow: a population genetic study of two stream invertebrates with differing dispersal abilities
Authors: ALP MARIA , KELLER IRENE , WESTRAM ANJA MARIE , ROBINSON CHRISTOPHER T. 
Published: March 2012

Summary1. Determined by landscape structure as well as dispersal‐related traits of species, connectivity influences various key aspects of population biology, ranging from population persistence to genetic structure and diversity. Here, we investigated differences in small‐scale connectivity in terms of gene flow between populations of two ecologically important invertebrates with contrasting dispersal‐related traits: an amphipod (Gammarus fossarum) with a purely aquatic life cycle and a mayfly (Baetis rhodani) with a terrestrial adult stage.2. We used highly polymorphic markers to estimate genetic differentiation between populations of both species within a Swiss pre‐alpine catchment and compared these results to the broader‐scale genetic structure within the Rhine drainage. Landscape genetic approaches were used to test for correlations of genetic and geographical structures and in‐stream barrier effects.3. We found overall very weak genetic structure in populations of B. rhodani. In contrast, G. fossarum showed strong genetic differentiation, even at spatial scales of a few kilometres, and a clear pattern of isolation by distance. Genetic diversity decreased from downstream towards upstream populations of G. fossarum, suggesting asymmetric gene flow. Correlation of genetic structure with landscape topography was more pronounced in the amphipod. Our study also indicates that G. fossarum might be capable of dispersing overland in headwater regions and of crossing small in‐stream barriers.4. We speculate that differences in dispersal capacity but also habitat specialisation and potentially the extent of local adaptation could be responsible for the differences in genetic differentiation found between the two species. These results highlight the importance of taking into account dispersal‐related traits when planning management and conservation strategies.
Meteorological drivers of the dynamics of autotrophic picoplankton
Authors: PELTOMAA ELINA , OJALA ANNE 
Published: March 2012

Summary1. The tiny non‐motile autotrophic picoplankton (APP; size range 0.2–2 μm) occur in all types of aquatic habitats and are comprised of prokaryotic as well as eukaryotic taxa. In the Boreal Zone, the majority of lakes have high concentrations of coloured humic substances that can adversely affect lake light climate and cause steep summertime stratification resulting in epilimnetic nutrient depletion. APP are more effective in nutrient and light acquisition than larger phytoplankton and thus should be competitive in humic lakes.2. Most lacustrine APP studies have been based on short sampling periods, and thus, interannual variation and its drivers are still unclear. We studied APP in the small, boreal, humic Lake Valkea‐Kotinen during five open‐water periods in 2002–06 to determine interannual variation and the importance of meteorological drivers for APP dynamics.3. Total APP showed a bimodal annual pattern, but the timing and vertical location of the two maxima varied during the study. In general, APP thrived in warm water and the most important abiotic factor controlling APP was stability of the water column (Ns). On average, 82% of APP were found in the epilimnion or metalimnion during summertime stratification.4. There was niche separation of APP and larger phytoplankton in the lake because, with only one exception, APP maxima occurred separately from the maxima of larger phytoplankton.5. Two groups, solitary eukaryotic APP and colonial picocyanobacteria (Merismopedia warmingiana), responded differently to the abiotic factors. Solitary APP preferred high water colour and low pH, both of which occurred after heavy rain, whereas colonial APP did not fare well when water colour was high. Our findings suggest that when future climate change‐related processes increase incoming allocthonous organic matter load from the catchment, solitary eukaryotic APP will be favoured.
Effects of burial on leaf litter quality, microbial conditioning and palatability to three shredder taxa
Authors: DANGER MICHAEL , CORNUT JULIEN , ELGER ARNAUD , CHAUVET ERIC 
Published: March 2012

Summary 1. Heterotrophic microorganisms are crucial for mineralising leaf litter and rendering it more palatable to leaf‐shredding invertebrates. A substantial part of leaf litter entering running waters may be buried in the streambed and thus be exposed to the constraining conditions prevailing in the hyporheic zone. The fate of this buried organic matter and particularly the role of microbial conditioning in this habitat remain largely unexplored.2. The aim of this study was to determine how the location of leaf litter within the streambed (i.e. at the surface or buried), as well as the leaf litter burial history, may affect the leaf‐associated aquatic hyphomycete communities and therefore leaf consumption by invertebrate detritivores. We tested the hypotheses that (i) burial of leaf litter would result in lower decomposition rates associated with changes in microbial assemblages compared with leaf litter at the surface and (ii) altered microbial conditioning of buried leaf litter would lead to decreased quality and palatability to their consumers, translating into lower growth rates of detritivores.3. These hypotheses were tested experimentally in a second‐order stream where leaf‐associated microbial communities, as well as leaf litter decomposition rates, elemental composition and toughness, were compared across controlled treatments differing by their location within the streambed. We examined the effects of the diverse conditioning treatments on decaying leaf palatability to consumers through feeding trials on three shredder taxa including a freshwater amphipod, of which we also determined the growth rate.4. Microbial leaf litter decomposition, fungal biomass and sporulation rates were reduced when leaf litter was buried in the hyporheic zone. While the total species richness of fungal assemblages was similar among treatments, the composition of fungal assemblages was affected by leaf litter burial in sediment.5. Leaf litter burial markedly affected the food quality (especially P content) of leaf material, probably due to the changes in microbial conditioning. Leaf litter palatability to shredders was highest for leaves exposed at the sediment surface and tended to be negatively related to leaf litter toughness and C/P ratio. In addition, burial of leaf litter led to lower amphipod growth rates, which were positively correlated with leaf litter P content.6. These results emphasise the importance of leaf colonisation by aquatic fungi in the hyporheic zone of headwater streams, where fungal conditioning of leaf litter appears particularly critical for nutrient and energy transfer to higher trophic levels.
Perceptual shifts of priority: a qualitative study bringing emotional intelligence to the foreground for nurses in talk‐based therapy roles
Authors: HURLEY J. 
Published: March 2012

Accessible summaryEmotional intelligence capabilities have been associated with the identity of mental health nurses and as being desired attributes by users of mental health services. Simultaneously, the nursing profession is increasing its delivery of talk‐based therapies, with policy‐driven preparation for such roles prioritizing therapy approaches rather than intrapersonal capability.This paper adds the voiced experiences of mental health nurses who construct a truth that a shifting of priorities toward developing emotionally intelligent capabilities is necessary for mental health nurses to successfully deliver talk‐based therapies.AbstractThis paper presents the findings of a qualitative study conceptually framed by social constructionism that explored the experiences of mental health nurses engaging in talk‐based therapy roles. Constructions from the participants' narratives are shown to have a powerful resonance with the construct of emotional intelligence, a resonance also echoed from the literature, and policies from the UK identified within the paper. Forwarded is that rather than prioritizing the development of technical approaches of specific therapies, nurses should equally be prepared for talk‐based therapy roles through developing their emotionally intelligence capabilities.
The orphan histidine protein kinase SgmT is a c‐di‐GMP receptor and regulates composition of the extracellular matrix together with the orphan DNA binding response regulator DigR in Myxococcus xanthus
Authors: Petters Tobias , Zhang Xin , Nesper Jutta , Treuner‐Lange Anke , Gomez‐Santos Nuria , Hoppert Michael , Jenal Urs , Søgaard‐Andersen Lotte 
Published: March 2012

SummaryIn Myxococcus xanthus the extracellular matrix is essential for type IV pili‐dependent motility and starvation‐induced fruiting body formation. Proteins of two‐component systems including the orphan DNA binding response regulator DigR are essential in regulating the composition of the extracellular matrix. We identify the orphan hybrid histidine kinase SgmT as the partner kinase of DigR. In addition to kinase and receiver domains, SgmT consists of an N‐terminal GAF domain and a C‐terminal GGDEF domain. The GAF domain is the primary sensor domain. The GGDEF domain binds the second messenger bis‐(3′‐5′)‐cyclic‐dimeric‐GMP (c‐di‐GMP) and functions as a c‐di‐GMP receptor to spatially sequester SgmT. We identify the DigR binding site in the promoter of the fibA gene, which encodes an abundant extracellular matrix metalloprotease. Whole‐genome expression profiling experiments in combination with the identified DigR binding site allowed the identification of the DigR regulon and suggests that SgmT/DigR regulates the expression of genes for secreted proteins and enzymes involved in secondary metabolite synthesis. We suggest that SgmT/DigR regulates extracellular matrix composition and that SgmT activity is regulated by two sensor domains with ligand binding to the GAF domain resulting in SgmT activation and c‐di‐GMP binding to the GGDEF domain resulting in spatial sequestration of SgmT.
Red blood cell storage and cell morphology
Authors: Blasi B. , D’Alessandro A. , Ramundo N. , Zolla L. 
Published: March 2012

Aim: In this study, we performed weekly assessment of morphology‐related parameters through monitoring of CPD‐SAGM leuco‐filtered erythrocyte concentrates from blood withdrawal until the 42nd day of storage.Background: Liquid storage of red blood cells (RBCs) delivers a blood‐derived therapeutic, which is safe, available, effective and affordable for most patients who need transfusion therapy in developed countries. However, a growing body of accumulating controversial evidences, from either biochemical or retrospective clinical studies, prompted safety concerns about longer stored RBCs.Methods: Statistical image analysis through scanning electron microscope was coupled to osmotic fragility and erythrocyte sedimentation rate.Results: We could observe that by day 21 more than 50% of RBCs displayed non‐discocyte phenotypes. This observation was related to an increase in osmotic fragility, which was totally overlapped in day 0 controls and day 7 RBCs while only slightly augmented in day 14 samples. Cation dysregulation (pH internal/external alteration and potassium) might both reflect and trigger a negative feedback loop with metabolic fluxes and membrane cation pumps.Conclusion: Morphology parameters suggest that significant alterations to RBC morphology over storage duration occur soon after the 14th day of storage, as to become significant enough within the 21st day.
Assessment of pain in sedated and mechanically ventilated patients: an observational study
Authors: JEITZINER M. ‐M. , SCHWENDIMANN R. , HAMERS J. P. H. , ROHRER O. , HANTIKAINEN V. , JAKOB S. M. 
Published: March 2012

BackgroundCritically ill patients often undergo unpleasant procedures. We quantified the effects of an unpleasant stimulus on physiological and behavioral parameters and evaluated how they are modified by sedation and analgesia.MethodsA 6‐month study in the 30‐bed intensive care unit (ICU) of a university hospital examined 21 sedated patients from various diagnostic groups. Hemodynamic and respiratory parameters, pupil size, facial expression, muscle tone, body movement, and the Richmond Agitation‐Sedation Scale (RASS) score were measured before and during intratracheal suctioning, first in sedated patients, after sedation was stopped, and after an opioid bolus.ResultsBefore intratracheal suctioning, patients had RASS scores of −1.8 ± 1.2 (mean ± standard deviation; sedation), −0.6 ± 1.7 (sedation stop), and −0.9 ± 1.4 (analgesia) (P = 0.014). Intratracheal suctioning significantly increased RASS during both sedation (to −0.6 ± 1.7) and sedation stop (to 1.0 ± 1.5) (both P < 0.01), but not during analgesia. Systolic blood pressure increased during sedation (by 9 ± 10 mmHg), during sedation stop (by 15 ± 17 mmHg) and during analgesia (by 9 ± 4 mmHg; all P < 0.01), but diastolic pressure only during sedation and sedation stop (both P < 0.01). Facial expression, body movement, and muscle tone changed significantly during the episodes of intratracheal suctioning. Heart rate, tidal volume, and pupil size remained stable under all conditions.ConclusionsIntratracheal suctioning evoked significant changes in some physiological and behavioral parameters. Some physiological changes were suppressed by analgesia, but at our ICU's standard doses, neither analgesia nor sedation attenuated changes in behavioral parameters at the intensity tested.
Effect of the menstrual cycle phase on post‐operative pain perception and analgesic requirements
Authors: AHMED A. , KHAN F. , ALI M. , HAQNAWAZ F. , HUSSAIN A. , AZAM S. I. 
Published: March 2012

BackgroundResearch has shown that menstrual cycle phase may affect pain sensitivity. There is a lack of studies evaluating this effect on post‐operative pain and analgesic needs.MethodsIn this prospective cohort study, we determined the effect of menstrual cycle phase on pain perception and analgesic requirements following total abdominal hysterectomy. Sixty women with regular menstrual cycles undergoing elective surgery were recruited and divided into ‘follicular’ and ‘luteal’ groups according to their menstrual history. Post‐operative pain was managed with intravenous patient‐controlled analgesia using tramadol. Intravenous morphine was used for rescue analgesia, and pain was assessed for 24 h.ResultsPain scores in the recovery room and ward six and 24 h post‐operatively were similar in the groups at rest and on coughing. Pain scores at rest 12 h post‐operatively were significantly higher in the luteal group (P = 0.043), while they were similar on coughing. There was no significant difference in the total tramadol requirement. Number of patients requiring rescue analgesia and the amount of morphine used was also similar.ConclusionThere was no difference in pain scores or analgesic requirements between the two groups except for rest pain at 12 h, which was significantly higher in the luteal group. As pain was assessed at 13 different time points, a significant difference seen only at one point could be due to random chance. We suggest that future research should concentrate on studying this issue in patients of relatively younger age groups with more pronounced hormonal variations during the cycle.
Effects of propofol with hyperthermia in a rat model of endotoxemic shock
Authors: MUKAWA C. , TANIGUCHI T. 
Published: March 2012

BackgroundWe aimed to investigate the effects of active mild hyperthermia and the effects of active mild hyperthermia with propofol on mortality and inflammatory responses during endotoxin‐induced shock in rats.MethodsIntravenous Escherichia coli endotoxin (15 mg/kg over 2 min) was injected in 48 rats. The animals were randomly allocated to one of the following four groups (n = 12 per group): normothermia group (group N), rectal temperature maintained between 36 °C and 38 °C; hyperthermia group (group H), rectal temperature was moderate and maintained between 39 °C and 40 °C; propofol with normothermia group (group PN), propofol (10 mg/kg/h) was administered, and temperature was between 36 °C and 38 °C; Propofol with hyperthermia group (group PH), propofol (10 mg/kg/h) administrated, and temperatures were maintained between 39 °C and 40 °C. The primary outcome was mortality 8 h after endotoxin injection. Secondary outcomes included changes in haemodynamics, arterial blood gases and plasma cytokine concentrations for the 8‐h observation period.ResultsMortality rates 8 h after endotoxin injection were 92%, 100%, 68% and 50% for N, H, PN and PH groups, respectively. There was no difference in hypotension, acidosis, and increase in plasma cytokine concentrations between N and H groups, but these parameters were attenuated in group PH.ConclusionThe mortality rates in the present study were extremely high; further hypotension and elevations in plasma pro‐inflammatory and anti‐inflammatory cytokine concentrations after endotoxin injection were not attenuated by mild hyperthermia between 39 °C and 40 °C, but they were attenuated by propofol with mild hyperthermia.
A clinical assessment tool for ultrasound‐guided axillary brachial plexus block
Authors: SULTAN S. F. , IOHOM G. , SAUNDERS J. , SHORTEN G. 
Published: March 2012

BackgroundCompetency in anesthesia traditionally has been determined subjectively in practice. Optimal training in procedural skills requires valid and reliable forms of assessment. The objective was to examine a procedure‐specific clinical assessment tool for ultrasound‐guided axillary brachial plexus block for inter‐rater reliability and construct validity in a clinical setting.MethodThis was a prospective observational study. Using prior work at our institution, the clinical assessment tool was developed consisting of a 63‐point task‐specific checklist and a global rating scale. The anesthesiologists were assigned to three groups based on prior experience of performing an axillary block: group 1 (‘novices’) < 10 procedures, group 2 (‘intermediates’) 50–80 procedures and group 3 (‘experts’) > 100 procedures. Each participant performed two consecutive blocks that were videotaped. Two blinded independent experts trained in the marking of the tool evaluated the videotapes.ResultsThere were five participants per group. The inter‐rater reliability between assessors was 0.842 and 0.795 for the checklist and global rating scale, respectively. There was a consistent difference between (each pair of) the three groups in terms of both the checklist and global rating scale (P < 0.05). For the checklist, expert vs. intermediate group P = 0.023, expert vs. novice group P < 0.001 and intermediate vs. novice group P = 0.019. For the global rating scale, expert vs. intermediate group P < 0.001, expert vs. novice group gave P < 0.001 and intermediate vs. novice group P = 0.023.ConclusionThe objective of task‐specific checklist and global rating scale are reliable and valid measures of axillary block performance between different levels of expertise.