bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plant diversity and land use under organic and conventional agriculture: a whole‐farm approach
Authors: GIBSON R. H. , PEARCE S. , MORRIS R. J. , SYMONDSON W. O. C. , MEMMOTT J. 
Published: March 2007

SummaryOrganic farming is thought to lead to increased biodiversity and greater sustainability than higher‐yielding conventional farming systems. It is usually assumed that organic farms have both larger and higher quality areas of semi‐natural habitats, although this assumption has not been unequivocally tested.Here we test the hypothesis that in comparison to conventional farms, organic farms have larger areas of semi‐natural and boundary vegetation, and organic farms support higher levels of plant abundance, richness and diversity within cropped and semi‐natural areas.Our study compared whole‐farms: 10 organic farms were paired with 10 conventional farms in a complex landscape in the south‐west of England. On average, organic farms were 7·3 years post conversion. Plant abundance, species richness and diversity were measured in all crop and non‐crop landscape elements on each farm.Organic farms had greater total areas of semi‐natural habitat (woodland, field margins and hedgerows combined). Woodland area on it's own was also significantly greater. Organic farms had more continuous blocks of woodland (with simpler perimeters than similarly sized patches on conventional farms), whereas woodland on conventional farms often consisted of more linear patches.Semi‐natural habitats on organic farms did not have higher plant abundance, richness or diversity than their conventional counterparts. The only landscape element that showed a significant increase in plant abundance, richness or diversity was arable fields.Synthesis and applications. Even within a complex agricultural landscape differences do exist between organic and conventional farms, these differences being larger areas of semi‐natural habitats on organic farms. However, with the exception of arable fields, no habitats on organic farms were yet of a better quality than their conventional counterparts in terms of plant abundance and diversity. Conventional farmers may be able to achieve an increase in plant diversity within arable fields by adopting some organic management practices at the field scale (e.g. exclusion of synthetic herbicides), and whole‐farm conversion to organic practice might not be required. However, further work is needed to determine any biodiversity benefits of larger areas of semi‐natural habitat on conventional farmland.
Forecasting suitable breeding conditions for the red‐billed quelea Quelea quelea in southern Africa
Authors: CHEKE ROBERT A. , VENN JON F. , JONES PETER J. 
Published: March 2007

Summary

Red‐billed queleas Quelea quelea are major pests of small‐grain crops throughout sub‐Saharan Africa. When conditions permit, birds breed in vast colonies which are targets for control operations. Queleas are intra‐African long‐distance migrants whose complex movements vary annually according to variations in rainfall patterns. An ability to forecast where and when colonies could be established will greatly improve the efficiency of control measures. We describe such a forecasting model for the southern African subspecies Q. q. lathamii.
The model is based on and provides a partial test of the conjectured rainfall–migration model of Ward (1971), whereby quelea movements are determined by rainfall patterns and grass seed availability. We consider that a threshold quantity of rainfall (shown here to be c. 60 mm) within any 2 weeks at the start of the wet season is necessary to cause annual grass seeds to germinate, forcing queleas to emigrate. Only if rainfall exceeds another threshold (240 mm within a 6‐week span and at least 6 weeks elapsed after the 60‐mm threshold had been exceeded), allowing production of fresh seed, can queleas return and commence breeding. Birds may breed again in the same season by undertaking further long‐distance ‘breeding migrations’ to areas where sufficient rain had fallen even later.
Using only estimates of rainfall derived from satellite data, we describe a simple spatio‐temporal model for southern Africa to show at weekly intervals those areas where (a) the wet season has not yet started; (b) the early rains migration threshold has been exceeded; (c) the threshold to permit breeding has been exceeded; and (d) conditions are no longer suitable for new colonies to be established.
Synthesis and applications. The model was run for three seasons and performed well compared to an expected null distribution of breeding colonies among quarter‐degree grid squares. In 2002/2003 and 2004/2005, but not in 2003/2004, quelea colonies were reported significantly more often in grid squares where the model had predicted breeding to be possible. However, in a more refined analysis of a smaller subset of colonies for which precise dates of their establishment were known, their spatio‐temporal distribution matched predictions in 95%, 85% and 99% of grid squares, respectively, over the three breeding seasons. These success rates show that predictions from the model, the first of its kind for any African bird, can aid the planning of quelea control strategies.
Landscape ecology of house mouse outbreaks in south‐eastern Australia
Authors: SINGLETON GRANT R. , TANN COLIN R. , KREBS CHARLES J. 
Published: March 2007

Summary

House mouse Mus domesticus outbreaks in the grain‐growing areas of south‐eastern Australia occur irregularly and may be local or widespread, covering thousands of square kilometres. All natural and agricultural habitats are occupied when house mouse numbers are high, and the question we addressed was whether we can distinguish source and sink habitats within these agricultural landscapes so that management practices can be better targeted.
Live‐trapping on replicated grids in 15 habitats, including eucalypt woodland, cypress pine woodland, areas of permanent water and crop habitats, was carried out from 1983 to 1988 at 9‐week intervals.
Agricultural cropland (including crops, fallow and pastures), farm buildings, seepage areas and natural woodland could be source habitats. Farm buildings, seepage areas and saltbush areas all had high mouse densities entering the 1983–84 outbreak and were refuge habitats for mice.
Cropland habitats quickly became the source area in spring 1983, and woodlands were initially sinks that lagged 2–4 months behind the population growth shown in crops.
Adult female mice in cropland habitats were more often in breeding condition compared with mice in natural woodland. Mice also had higher indices of residency in cropland than in natural woodland.
Synthesis and applications. In non‐irrigated cereal production areas of south‐eastern Australia, house mice move from refuge habitats in seepage areas and farm buildings into crops, build up in numbers in cropland habitats, and then invade woodland habitats, which by themselves cannot generate outbreaks of this pest species. Monitoring for incipient outbreaks should concentrate on refuges in seepage areas and crops and their associated fence lines as source habitat indicators. Population control in these habitats in spring would reduce the likelihood of population outbreaks in autumn, leading to reduced rodenticide use and a concomitant reduction in environmental hazards.
Managing heterogeneity in elephant distribution: interactions between elephant population density and surface‐water availability
Authors: CHAMAILLÉ‐JAMMES SIMON , VALEIX MARION , FRITZ HERVÉ 
Published: March 2007

SummaryConcerns over the ecological impacts of high African elephantLoxodonta africanadensities suggest that it may be necessary to control their numbers locally, although the best management approach is still widely debated. Artificial water supply is believed to be a major cause of local overabundance, and could be used as a potential tool to regulate elephant distribution and impact across landscapes, but its effect on elephants at the population scale has never been studied.We assessed how dry‐season surface‐water availability constrained the distribution of an entire elephant population, using aerial and waterhole census data from Hwange National Park, Zimbabwe. The study was initiated in 1986, when the population was released from culling. We studied how artificial waterholes, holding water throughout the dry season, and vegetation production, estimated from a normalized difference vegetation index (NDVI), influenced the long‐term distribution of elephant densities. We also investigated how the elephant distribution responded to changes in population density and annual rainfall, a driver of surface‐water availability.Long‐term dry‐season elephant densities across the park tended to increase with vegetation production, and increased asymptotically with the density of artificial waterholes.Since the culling stopped, dry‐season elephant densities have increased in most areas of the park, except in areas of low vegetation production and low water availability. Interannual fluctuations in elephant distribution are linked to rainfall variability through its effect on surface‐water availability. During dry years elephants concentrated in areas where artificial pumping maintained surface‐water availability during the dry season.During dry years elephant numbers at waterholes increased because of reduced surface‐water availability, and elephants were distributed more evenly across waterholes, although active waterholes were unevenly distributed across the park.Synthesis and applications. Surface‐water availability drives the distribution and abundance of elephants within Hwange National Park, and therefore appears to be at the heart of the trade‐off between elephant conservation and the extent of their impact on ecosystems. Artificial manipulation of surface water is one of the tools available for the management of elephant populations and should not be overlooked when considering options for controlling elephant numbers in places where they are considered to be overabundant.
Peripheral immune responses in pregnant cattle following Neospora caninum infection
Authors: ROSBOTTOM A. , GUY C. S. , GIBNEY E. H. , SMITH R. F. , VALARCHER J. F. , TAYLOR G. , WILLIAMS D. J. L. 
Published: March 2007

SUMMARY Experimental infection of cattle with Neospora caninum in early gestation causes foetal death, but the foetus survives infection in late gestation. An immunological mechanism of abortion has been suggested; therefore changes in the maternal immune response during pregnancy could account for these differences. We have investigated the peripheral immune responses of pregnant cattle following an intravenous inoculation with 107 N. caninum tachyzoites in early and late gestation. Percentages of CD2+ and CD4+ T‐cells in peripheral blood mononuclear cells (PBMC) increased 1–2 weeks after infection in both early (day 70) and late (day 210) gestation, and percentages of CD8+ T‐cells increased 1–2 weeks after infection at day 70. Interleukin‐4 (IL‐4) and interferon‐γ (IFN‐γ) mRNA expression in PBMC increased 1–2 weeks after infection at day 210 and IL‐4 increased 1–2 weeks after infection at day 70. Immunomagnetic isolation of CD4+ cells from PBMC showed that they were a major source of IL‐4 and IFN‐γ, and expression of both cytokines increased in CD4+ cells after infection in early and late gestation. These results suggest that CD4+ cells proliferate and express IL‐4 and IFN‐γ in response to N. caninum irrespective of the stage of gestation when infection occurs.
Nomenclature of prominin‐1 (CD133) splice variants – an update
Authors: Fargeas C. A. , Huttner W. B. , Corbeil D. 
Published: March 2007

AbstractProminin‐1 (CD133), a pentaspan membrane glycoprotein that constitutes an important cell surface marker of various, either normal or cancerous, stem cell populations is widely used to isolate or characterize such cells in different systems. Occurring throughout the metazoan evolution with a remarkably conserved genomic organization, it may be expressed as different splice variants with distinctive characteristics. A rational nomenclature has been proposed earlier for their consistent designation across species. Although generally accepted, it seems to be misunderstood in view of the recent report of novel prominin‐1 complementary DNAs in rhesus monkey and humans with improper naming. As this may lead to confusion, we have reexamined the genomic organization of prominin‐1 in various primates to provide an update that should further clarify the rationale of the nomenclature for prominin‐1 gene products. This report comprises (i) the determination of the genomic organization of prominin‐1 gene in two non‐human primates, i.e. Macaca mulatta and Pan troglodytes, commonly used in research, (ii) the mapping of a new exon that creates an alternative cytoplasmic C‐terminal end of prominin‐1, (iii) the identification of various potential PDZ‐binding domains generated by alternative cytoplasmic C‐terminal tails, suggesting that different prominin‐1 splice variants might interact with distinct protein partners, and (iv) a summing up of the different prominin‐1 splice variants.
Ketamine, an NMDA‐antagonist, increases the oscillatory frequencies of α‐peaks on the electroencephalographic power spectrum
Authors: Tsuda N. , Hayashi K. , Hagihira S. , Sawa T. 
Published: March 2007

Background:  Ketamine, an N‐methyl‐D‐aspartate (NMDA) antagonist, is known to activate the electroencephalogram (EEG), despite its sedative effects. Spindle oscillations are known to be related to the sedative actions of the reticular thalamic nucleus with links to thalamocortical neurons. This study was designed to examine the effect of ketamine on the spindle oscillations to understand the simultaneous sedative effect and EEG activation that occurs with ketamine, by comparing the EEG in emergence.Methods:  Anesthesia was induced with propofol using a target‐controlled infusion (TCI) system (3.5 μg/ml). Seventeen patients, scheduled for non‐cranial surgery under general anesthesia combined with epidural anesthesia, were randomly divided into two groups: (i) anesthesia was maintained with TCI‐propofol alone (n= 8) and (ii) anesthesia was maintained with TCI‐propofol and intravenously administered ketamine (n= 9). The EEG was continuously monitored and EEG indices and power spectra were determined.Results:  Propofol alone caused the α‐peaks of the power spectra to occur at an average frequency of 10.4 ± 0.9 Hz; the addition of ketamine shifted the peaks to higher frequencies of 15.1 ± 1.4 Hz (P < 0.05). On the other hand, when the EEG was activated by discontinuation of propofol, the corresponding α‐peaks disappeared.Conclusions:  Ketamine increased the frequencies of α‐spindle waves induced by propofol, but did not block their formations. The phenomena have the possibility to underlie the cooperative effect between propofol and ketamine concerning sedation and anesthesia.
Family presence and environmental factors at the time of a patient’s death in an ICU
Authors: Fridh I. , Forsberg A. , Bergbom I. 
Published: March 2007

Background:  In an intensive care unit (ICU), privacy and proximity are reported to be important needs of dying patients and their family members. It is assumed that good communication between the ICU team and families about end‐of‐life decisions improves the possibilities of meeting families’ needs, thus guaranteeing a dignified and peaceful death in accordance with end‐of‐life care guidelines. The aim of this study was to explore the circumstances under which patients die in Swedish ICUs by reporting on the presence of family and whether patients die in private or shared rooms. An additional aim was to investigate the frequency of end‐of‐life decisions and whether nurses and family members were informed about such decisions.Methods:  A questionnaire based on the research questions was completed when a patient died in the 10 ICUs included in the study. Data were collected on 192 deaths.Results:  Forty per cent of the patients died without a next of kin at the bedside and 46% of deaths occurred in a shared room. This number decreased to 37% if a family member was present. Patients without a family member at their bedside received less analgesics and sedatives. There was a significant relationship between family presence, expected death and end‐of‐life decisions.Conclusions:  The results indicate the necessity of improving the ICU environment to promote the need for proximity and privacy for dying patients and their families. The study also highlights the risk of underestimating the needs of patients without a next of kin at their bedside at the time of death.
Sustained intravascular exposure to propofol does not prolong pain at the site of injection
Authors: Liljeroth E. , Karlsson A. , Lagerkranser M. , ÅKeson J. 
Published: March 2007

Background:  Pain at the site of intravenous injection of propofol is a common clinical finding. This double‐blind, randomized cross‐over study was designed to evaluate whether venous occlusion applied during injection of a low dose of propofol reduces the intensity of pain at the site of injection compared with no occlusion.Methods:  Bilateral 0.5‐ml injections of an emulsion containing 10 mg/ml of propofol were given over 30 s in 75 adult surgical patients. Each patient was given one injection with and one without 60‐s occlusion of the cannulated vein with a 10‐min interval, and asked to score the maximal pain intensity on a visual analogue scale (VAS).Results:  The maximal pain intensity [median (25th percentile; 75th percentile), range] at the site of injection was 0.5 (0; 3.5), 0–8.0 VAS units with venous occlusion and 0.5 (0; 1.4), 0–6.0 VAS units without occlusion (P= 0.042). Pain was first reported within 20 s regardless of the study regimen and was not prolonged by local venous occlusion.Conclusion:  Venous occlusion augments pain intensity at the site of propofol injection without prolonging pain, implying that propofol‐induced pain is determined more by the blood concentration than by the duration of intravascular exposure. The low intensity of pain induced by low‐dose propofol and the fading of pain despite sustained exposure suggest that initial low‐dose administration of propofol should be evaluated for the attenuation of local pain induced by higher intravenous doses of propofol.
Does a positive end‐expiratory pressure‐induced reduction in stroke volume indicate preload responsiveness? An experimental study
Authors: Lambert P. , Sloth E. , Smith B. , Hansen L. K. , Koefoed‐Nielsen J. , Tønnesen E. , Larsson A. 
Published: March 2007

Background:  Increases in positive end‐expiratory pressure (PEEP) are often associated with cardiovascular depression, responding to fluid loading. Therefore, we hypothesized that if stroke volume (SV) is reduced by an increase in PEEP this reduction is an indicator of hypovolemia or preload responsiveness, i.e. that SV would increase by fluid administration at zero end‐expiratory pressure (ZEEP). The relationship between the cardiovascular response to different PEEP levels and fluid load as well as the relation between change in SV as a result of change in preload (Frank–Starling relationship) were evaluated in a porcine model. In addition, other measures of fluid status were assessed.Methods:  Eight, 20–22 kg, anesthetized, mechanically ventilated pigs were subjected to 0, 10, and 20 cm H2O PEEP at 10% (of estimated blood volume) hypovolemia, normo‐ and 10% hypervolemia, and to ZEEP at 20% hypervolemia. SV, cardiac output, intrathoracic blood volume and airway, esophageal, vascular pressures, stroke volume variations, left ventricular end‐diastolic and end‐systolic areas and respiratory variations in the diameter of the inferior vena cava were obtained.Results:  At hypovolemia and normovolemia, 10 cm H2O PEEP induced a significant decrease in SV, while no change occurred at 10% hypervolemia. SV measured at ZEEP increased from hypovolemia to normovolemia and 10% hypervolemia, while no change was found between 10% and 20% hypervolemia. The sensitivity and specificity decrease in SV by PEEP indicating an increase in SV by fluids was 60–88% and 67%, respectively, depending on the volemic (preload) levels.Conclusion:  Although the overall results suggest that a change in SV by PEEP might predict preload responsiveness, the individual response of SV by 10 cm H2O PEEP and of the successive fluid administration seemed to be dependent on where on the Frank–Starling curve the heart function was located.
Pre‐occlusion ischaemia, not sevoflurane, successfully preconditions the myocardium against further damage in porcine in vivo hearts
Authors: Larsen J. R. , Aagaard S. R. , Hasenkam J. M. , Sloth E. 
Published: March 2007

Background:  Sevoflurane is proposed to possess important tissue protective effects based on experimental ischaemia‐reperfusion studies from models with collateral coronary flow, unlike that of the normal human or the porcine heart. The objective was to evaluate the infarct‐reducing capability of pre‐ischaemic sevoflurane inhalation on myocardial infarct size in a porcine model.Methods and materials:  The study comprised 33 pigs under pentobarbital anaesthesia. Animals were divided into three groups: control (CON), sevoflurane intervention (SEVO) and ischaemic preconditioning (IP). The distal left anterior descending coronary artery was occluded for 40 min with a percutaneous coronary intervention catheter. Before occlusion, group IP underwent two 5‐min ischaemia cycles, whereas SEVO received two 5‐min sevoflurane 4%v/v inhalation cycles. Animals were reperfused for 150 min. We then measured risk area (AAR) and infarct size (IS) after tetrazolium staining. The [IS/AAR‐ratio] was calculated. Haemodynamics and transthoracic tissue‐Doppler echocardiography were monitored.Results:  Control animals developed a myocardial infarction in 46.4 (± 6.2)% (mean ± SEM) of the AAR. Both SEVO and IP groups had infarction mitigated, to 34.4 (5.7)% and 23.1 (5.3)%, respectively; however, only in the IP group was this significant. No significant differences between groups with respect to AAR, haemodynamics or echocardiographic variables were found.Conclusion:  Pre‐ischaemic sevoflurane was found to reduce the extent of myocardial necrosis, but the change was not significant, whereas IP reduced IS by 50% (P= 0.038). Cardioprotection is species related and no previous results from porcine models have found sevoflurane to reduce IS. Anaesthetic washout, insufficient exposure or collateral coronary blood supply, dissimilar to human, may account for positive results in rodent models.