549 research outputs found
Carabid beetle and spider assemblages along a forested urbanārural gradient in southern Finland
To investigate the effects of urbanization on carabid beetles (Carabidae) and ground dwelling spiders (Araneae)
a study was completed along a 20 kmurbanārural forest gradient in the HelsinkiāEspoo area of southern Finland. To
study changes in assemblage structure, abundance and species richness, these taxa were collected in the year 2000
using pitfall traps, which had been placed in four forest sites within each of the urban, suburban and rural zones.We
expected to find changes in the abundances and species richnesses in the two taxa across the urbanārural gradient,
but did not find any. Our second and third hypotheses, stating that generalist species and small-bodied species should
gain dominance along the gradient from rural to urban sites, were partly supported as carabid specialists were more
characteristic of suburban and rural environments whereas generalists were more likely to be collected from rural
areas compared to suburban or urban sites. Furthermore, medium to large-sized carabid individuals were more likely
to be collected in the rural sites compared to urban forests. We found no evidence for significant changes in spider
abundance or species richness across the urbanārural gradient in relation to body size or habitat specialization. We
suggest that urbanization does not have significant effects on the total abundances and species richnesses in these
two taxa. However, individual species responded differently to urbanization, and there were significant differences
in the specialization and body sizes of carabids across the gradient
Quantifying Long-Term Urban Grassland Dynamics: Biotic Homogenization and Extinction Debts
Sustainable urban nature conservation calls for a rethinking of conventional approaches. Traditionally, conservationists have not incorporated the history of the landscape in management strategies. This study shows that extant vegetation patterns are correlated to past landscapes indicating potential extinction debts. We calculated urban landscape measures for seven time periods (1938ā2019) and correlated it to three vegetation sampling events (1995, 2012, 2019) using GLM models. We also tested whether urban vegetation was homogenizing. Our results indicated that urban vegetation in our study area is not currently homogenizing but that indigenous forb species richness is declining significantly. Furthermore, long-term studies are essential as the time lags identified for different vegetation sampling periods changed as well as the drivers best predicting these changes. Understanding these dynamics are critical to ensuring sustainable conservation of urban vegetation for future citizens
Has the character of gastric cancer changed? A descriptive study of a IO-year period
Over the 10-year period January 1976 - December 1985, 446 patients with histologically verified adenocarcinoma of the stomach were treated at Tygerberg Hospital. Coloured patients made up 63,4% of the study population and a significant increase in the annual proportion of this group was observed. Coloured men comprised 47,6% of the total group. The mean age of white and coloured patients differed significantly (68,9 v. 56,5; P < 0,001). The symptom complex was essentially similar in the two racial groups and in general the character of the symptoms had no bearing on the prevalence of resection. Although antral tumours were most common in whites and in coloureds, there was a significant increase in tumours located in the fundus in whites. The resection rate remained unchanged over the 10-year period. Only 4 cases of early gastric cancer were detected during this period without any signs of an increased yield of early lesions over time. This audit revealed no beneficial changes over time, which is in stark contrast with reports from Japan regarding the proportion of curable lesions
Exploring the anthelmintic properties of Australian native shrubs with respect to their potential role in livestock grazing systems
We measured in vitro anthelmintic activity in extracts from 85 species of Australian native shrub, with a view to identifying species able to provide a degree of worm control in grazing systems. Approximately 40% of the species showed significant activity in inhibiting development of Haemonchus contortus larvae. The most active extracts showed IC50 values of 60ā300 mg/ml. Pre-incubation with polyvinylpolypyrrolidine removed the activity from some extracts, implicating tannins as the bioactive agent, while in other cases the pre-incubation had no effect, indicating the presence of other anthelmintic compounds. Plant reproductive maturity (onset of flowering or fruiting) was associated with increasing anthelmintic activity in some species. Variability was observed between plants of the same species growing in different environments, while variation between individual plants of the same species within a single field suggests the existence of distinct chemotypes. Significant activity against adult H. contortus worms in vitro was also demonstrated in a limited number of extracts tested against this life stage. Our study indicates that there is potential for Australian native shrubs to play an anthelmintic role in grazing systems, and highlights some plant biology factors which will need to be considered in order to maximize any anthelmintic effects.A. C. Kotze, J. OāGrady, J. Emms, A. F. Toovey, S. Hughes, P. Jessop, M. Bennell P. E. Vercoe and D. K. Revel
IGR J19552+0044: A new asynchronous short period polar: "Filling the gap between intermediate and ordinary polars"
Based on XMM--Newton X-ray observations IGR J19552+0044 appears to be either
a pre-polar or an asynchronous polar. We conducted follow-up optical
observations to identify the sources and periods of variability precisely and
to classify this X-ray source correctly. Extensive multicolor photometric and
medium- to high-resolution spectroscopy observations were performed and period
search codes were applied to sort out the complex variability of the object. We
found firm evidence of discording spectroscopic (81.29+/-0.01m) and photometric
(83.599+/-0.002m) periods that we ascribe to the white dwarf (WD)\ spin period
and binary orbital period, respectively. This confirms that IGR J19552+0044 is
an asynchronous polar. Wavelength-dependent variability and its continuously
changing shape point at a cyclotron emission from a magnetic WD with a
relatively low magnetic field below 20 MG.
The difference between the WD spin period and the binary orbital period
proves that IGR J19552+0044 is a polar with the largest known degree of
asynchronism (0.97 or 3%).Comment: 9 pages, 10 figures, A&A accepte
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Factors supporting and constraining the implementation of robot-assisted surgery: a realist interview study
YesTo capture stakeholdersā theories concerning how and in what contexts robot-assisted surgery becomes integrated into routine practice.
A literature review provided tentative theories that were revised through a realist interview study. Literature-based theories were presented to the interviewees, who were asked to describe to what extent and in what ways those theories reflected their experience. Analysis focused on identifying mechanisms through which robot-assisted surgery becomes integrated into practice and contexts in which those mechanisms are triggered.
Nine hospitals in England where robot-assisted surgery is used for colorectal operations.
Forty-four theatre staff with experience of robot-assisted colorectal surgery, including surgeons, surgical trainees, theatre nurses, operating department practitioners and anaesthetists.
Interviewees emphasised the importance of support from hospital management, team leaders and surgical colleagues. Training together as a team was seen as beneficial, increasing trust in each otherās knowledge and supporting team bonding, in turn leading to improved teamwork. When first introducing robot-assisted surgery, it is beneficial to have a handpicked dedicated robotic team who are able to quickly gain experience and confidence. A suitably sized operating theatre can reduce operation duration and the risk of de-sterilisation. Motivation among team members to persist with robot-assisted surgery can be achieved without involvement in the initial decision to purchase a robot, but training that enables team members to feel confident as they take on the new tasks is essential.
We captured accounts of how robot-assisted surgery has been introduced into a range of hospitals. Using a realist approach, we were also able to capture perceptions of the factors that support and constrain the integration of robot-assisted surgery into routine practice. We have translated these into recommendations that can inform future implementations of robot-assisted surgery
The effects of drainage and restoration of pine mires on habitat structure, vegetation and ants
Habitat loss and degradation are the main threats to biodiversity worldwide. For example, nearly 80% of peatlands in southern Finland have been drained. There is thus a need to safeguard the remaining pristine mires and to restore degraded ones. Ants play a pivotal role in many ecosystems and like many keystone plant species, shape ecosystem conditions for other biota. The effects of mire restoration and subsequent vegetation succession on ants, however, are poorly understood. We inventoried tree stands, vegetation, water-table level, and ants (with pitfall traps) in nine mires in southern Finland to explore differences in habitats, vegetation and ant assemblages among pristine, drained (30-40 years ago) and recently restored (1-3 years ago) pine mires. We expected that restoring the water-table level by ditch filling and reconstructing sparse tree stands by cuttings will recover mire vegetation and ants. We found predictable responses in habitat structure, floristic composition and ant assemblage structure both to drainage and restoration. However, for mire-specialist ants the results were variable and longer-term monitoring is needed to confirm the success of restoration since these social insects establish perennial colonies with long colony cycles. We conclude that restoring the water-table level and tree stand structure seem to recover the characteristic vegetation and ant assemblages in the short term. This recovery was likely enhanced because drained mires still had both acrotelm and catotelm, and connectedness was still reasonable for mire organisms to recolonize the restored mires either from local refugia or from populations of nearby mires.Peer reviewe
A realist process evaluation of robot-assisted surgery: integration into routine practice and impacts on communication, collaboration and decision-making
YesBackground: The implementation of robot-assisted surgery (RAS) can be challenging, with reports of surgical robots being underused. This raises questions about differences compared with open and laparoscopic surgery and how best to integrate RAS into practice. Objectives: To (1) contribute to reporting of the ROLARR (RObotic versus LAparoscopic Resection for Rectal cancer) trial, by investigating how variations in the implementation of RAS and the context impact outcomes; (2) produce guidance on factors likely to facilitate successful implementation; (3) produce guidance on how to ensure effective teamwork; and (4) provide data to inform the development of tools for RAS. Design: Realist process evaluation alongside ROLARR. Phase 1 ā a literature review identified theories concerning how RAS becomes embedded into practice and impacts on teamwork and decision-making. These were refined through interviews across nine NHS trusts with theatre teams. Phase 2 ā a multisite case study was conducted across four trusts to test the theories. Data were collected using observation, video recording, interviews and questionnaires. Phase 3 ā interviews were conducted in other surgical disciplines to assess the generalisability of the findings. Findings: The introduction of RAS is surgeon led but dependent on support at multiple levels. There is significant variation in the training provided to theatre teams. Contextual factors supporting the integration of RAS include the provision of whole-team training, the presence of handpicked dedicated teams and the availability of suitably sized operating theatres. RAS introduces challenges for teamwork that can impact operation duration, but, over time, teams develop strategies to overcome these challenges. Working with an experienced assistant supports teamwork, but experience of the procedure is insufficient for competence in RAS and experienced scrub practitioners are important in supporting inexperienced assistants. RAS can result in reduced distraction and increased concentration for the surgeon when he or she is supported by an experienced assistant or scrub practitioner. Conclusions: Our research suggests a need to pay greater attention to the training and skill mix of the team. To support effective teamwork, our research suggests that it is beneficial for surgeons to (1) encourage the team to communicate actions and concerns; (2) alert the attention of the assistant before issuing a request; and (3) acknowledge the scrub practitionerās role in supporting inexperienced assistants. It is beneficial for the team to provide oral responses to the surgeonās requests. Limitations: This study started after the trial, limiting impact on analysis of the trial. The small number of operations observed may mean that less frequent impacts of RAS were missed. Future work: Future research should include (1) exploring the transferability of guidance for effective teamwork to other surgical domains in which technology leads to the physical or perceptual separation of surgeon and team; (2) exploring the benefits and challenges of including realist methods in feasibility and pilot studies; (3) assessing the feasibility of using routine data to understand the impact of RAS on rare end points associated with patient safety; (4) developing and evaluating methods for whole-team training; and (5) evaluating the impact of different physical configurations of the robotic console and team members on teamwork.National Inst for Health Research (NIHR
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