Whereas a lot of marine research work has been done on heavy metals and semivolatile organic compounds, far less attention has been paid to the fate of volatile organic compounds in this area. This ...work focuses on 13 volatile organic compounds in marine waters and the marine atmosphere. During six campaigns in September 1994−December 1995, simultaneous air and water sampling was carried out in both the southern North Sea area and the Scheldt Estuary. Mean water concentrations for individual compounds were in the 2.2−72.9 ppt range (n = 38), whereas atmospheric concentrations varied between 2.3 and 854 pptv. Samples from the Scheldt Estuary proved to have elevated concentrations of chlorinated compounds. A number of water and air samples showed enhanced concentrations of C2-substituted monocyclic aromatic hydrocarbons, which could not clearly be linked to anthropogenic activities. Back-trajectory calculations showed that a number of over sea atmospheric samples were affected by atmospheric transport from industrial sites, 250−300 km up wind. Fugacity modeling showed that the North Sea acts as a source to the atmosphere, not as a sink. Mean water to air mass transfer rates varied between 0.6−52.7 μg m-2 day-1 for all VOCs. It was statistically shown that water to air exchange rates of tetrachloroethylene, benzene, and toluene were slowed when air masses from continental origin were at the marine sampling sites instead of air masses from remote noncontinental origin.
Background
A right- or left-sided liver resection can be considered in about half of patients with perihilar cholangiocarcinoma (pCCA), depending on tumor location and vascular involvement. This ...study compared postoperative mortality and long-term survival of right- versus left-sided liver resections for pCCA.
Methods
Patients who underwent major liver resection for pCCA at 25 Western centers were stratified according to the type of hepatectomy—left, extended left, right, and extended right. The primary outcomes were 90-day mortality and overall survival (OS).
Results
Between 2000 and 2022, 1701 patients underwent major liver resection for pCCA. The 90-day mortality was 9% after left-sided and 18% after right-sided liver resection (
p
< 0.001). The 90-day mortality rates were 8% (44/540) after left, 11% (29/276) after extended left, 17% (51/309) after right, and 19% (108/576) after extended right hepatectomy (
p
< 0.001). Median OS was 30 months (95% confidence interval CI 27–34) after left and 23 months (95% CI 20–25) after right liver resection (
p
< 0.001), and 33 months (95% CI 28–38), 27 months (95% CI 23–32), 25 months (95% CI 21–30), and 21 months (95% CI 18–24) after left, extended left, right, and extended right hepatectomy, respectively (
p
< 0.001). A left-sided resection was an independent favorable prognostic factor for both 90-day mortality and OS compared with right-sided resection, with similar results after excluding 90-day fatalities.
Conclusions
A left or extended left hepatectomy is associated with a lower 90-day mortality and superior OS compared with an (extended) right hepatectomy for pCCA. When both a left and right liver resection are feasible, a left-sided liver resection is preferred.
To motivate farmers for the implementation of preventive measures for animal health, it is crucial to understand their perspective on disease prevention and on-farm biosecurity. To study this, an ...online questionnaire was conducted in which 218 pig, 279 cattle and 61 poultry farmers in Flanders, Belgium have participated. The participants are farmers known for their interest in research and are therefore probably better informed on these topics. Although approximately half of the respondents in all three sectors are convinced of the positive effect of biosecurity on reduction of diseases at their farms, the farmers estimated their own level of knowledge on biosecurity as being rather low. Less than 10% of the farmers in all three sectors were able to give a correct explanation of the term 'biosecurity', even though the participants are likely to be better informed than the average farmer. In general, pig, cattle and poultry farmers share comparable ideas on disease prevention and biosecurity. Cattle farmers perceived animal welfare as more important. Pig farmers indicated stability of the farm more important than farmers in the other sectors. Farmers indicate that little to no barriers are present for taking preventive measures. The often observed absence or limited implementation of biosecurity and disease prevention measures is therefore likely due to insufficient motivation. Across the species, farmers indicate that insufficient information on costs and especially revenues is a major holdback for investments in preventive measures. Not surprisingly, more information on the economic benefits of measures is indicated as the primary interest for taking measures in disease prevention. The veterinarian is seen as the main source of information concerning disease prevention and biosecurity, so it is important that veterinarians have sufficient knowledge on these topics and are able to communicate this to farmers. Especially since farmers indicate that receiving more explanation by the herd veterinarian increases their interest substantially in disease prevention.
Resuming an Unfinished Tale Schraven, Daan F. J.; Hartmann, Andreas; Dewulf, Geert P. M. R.
Organizational research methods,
04/2015, Letnik:
18, Številka:
2
Journal Article
Recenzirano
In aiming to understand how structures, such as rules, norms, and routines, establish inside organizations, scholars now focus their explanation on practitioners who enact a multitude of behavioral ...logics. Studies adopting this institutional logic perspective apply assumptions about the apparency and dominance of logics and consequently cannot adequately explain, with empirical evidence, how logics coexist or compete for dominance among practitioners. To fill this gap, we open these concepts up to recent academic inquiry as to the dominant logics that practitioners enact. In so doing, we address the still unanswered call by Von Krogh and Roos to collect empirical evidence on dominant logics by operationalizing two concepts: self-reference and self-similarity. We introduce a methodology that involves causal mapping enhanced with statistical tests and graphical approaches. Through an empirical investigation, we show how this method provides the enacted patterns of multiple logics, validates their dominance, and detects internal contradictions and inconsistencies. These findings highlight that if one defines dominant logics in terms of self-reference and self-similarity, causal mapping then generates competing and coexisting logics that practitioners enact.
Coping with ambiguities in natural resources management has become unavoidable. Ambiguity is a distinct type of uncertainty that results from the simultaneous presence of multiple valid, and ...sometimes conflicting, ways of framing a problem. As such, it reflects discrepancies in meanings and interpretations. Under the presence of ambiguity it is not clear what problem is to be solved, who should be involved in the decision processes or what is an appropriate course of action. Despite the extensive literature about methodologies and tools to deal with uncertainty, not much has been said about how to handle ambiguities. In this paper, we discuss the notions of framing and ambiguity, and we identify five broad strategies to handle it: rational problem solving, persuasion, dialogical learning, negotiation and opposition. We compare these approaches in terms of their assumptions, mechanisms and outcomes and illustrate each approach with a number of concrete methods.
•We investigate the role of ICT4D and citizen science in facilitating knowledge co-creation.•We introduce the conceptual framework for decentralized information sharing platforms, Environmental ...Virtual Observatories.•We explore the potential of EVOs to improve adaptive decision-making in six rural case-study areas in Africa.•We complement the existing theory on EVOs with a focused exploration of ICT-enabled multi-stakeholder exchange.
Climate change, (a) biotic stresses and environmental degradation are adversely affecting the sustenance of farming communities in Africa. Addressing such challenges requires effective collective action and coordination among stakeholders, which often prove difficult to achieve. Timely and context-specific information on relevant environmental dynamics holds considerable promise to overcome these problems.
This paper investigates the role of citizen science in facilitating knowledge co-creation and sharing between academia, development actors and users in developing country contexts. In our approach, we focus on information sharing platforms (known as Environmental Virtual Observatories, EVOs) and their potential to facilitate adaptive decision-making in six rural case-study areas in Africa.
We complement the existing theory on EVOs with a focused exploration of the connective function of ICT-enabled multi-stakeholder exchange. We propose that increased connectivity may enable new forms of collective action (labelled ‘connective action’), relevant to addressing socio-ecological challenges. Along these lines, this paper presents the theoretical and conceptual grounding of a research program that aspires to develop Environmental Virtual Observatories for Connective Action (EVOCAs) and to explore their potential for improved crop, water, livestock and disease management in rural Africa.
Aims: The behaviour of an Escherichia coli isolate of broiler origin harbouring a blaTEM-₅₂-carrying plasmid (lactose-negative mutant of B1-54, IncII group) was studied in an in situ continuous flow ...culture system, simulating the human caecum and the ascending colon during cefotaxime administration. Methods and Results: Fresh faeces from a healthy volunteer, negative for cephalosporin-resistant E. coli, were selected to prepare inocula. The microbiota was monitored by plating on diverse selective media, and a shift in the populations of bacteria was examined by 16S rDNA PCR denaturing gradient gel electrophoresis. Escherichia coli transconjugants were verified by plasmid and pulsed-field gel electrophoresis profiles (PFGE). The avian extended-spectrum β-lactamase-positive E. coli was able to proliferate without selective pressure of cefotaxime, and E. coli transconjugants of human origin were detected 24 h after inoculation of the donor strain. Upon administration of cefotaxime to the fresh medium, an increase in the population size of E. coli B1-54 and the transconjugants was observed. PFGE and plasmid analysis revealed a limited number of human E. coli clones receptive for the blaTEM-₅₂-carrying plasmid. Conclusions: These observations provide evidence of the maintenance of an E. coli strain of poultry origin and the horizontal gene transfer in the human commensal bowel microbiota even without antimicrobial treatment. Significance and Impact of the Study: The fact that an E. coli strain of poultry origin might establish itself and transfer its bla gene to commensal human E. coli raises public health concerns.
Ozonation of the quinolone antibiotic levofloxacin was investigated with focus on both the levofloxacin degradation rate and degradation product formation. Degradation was about 2 times faster at pH ...10 compared to pH 3 and 7 explained by direct ozonation at the unprotonated
N
4
′
, one of the tertiary amines of the piperazinyl substituent. H
2O
2 concentration (2–100
μM) had only limited effect. Liquid chromatography – high resolution mass spectrometry revealed degradation at the piperazinyl substituent and the quinolone moiety, with the relative importance of both pathways being strongly affected by changes in pH. Levofloxacin N-oxide concentrations reached up to 40% of the initial levofloxacin concentration during ozonation at pH 10. Degradation at the quinolone moiety resulted in isatin and anthranilic acid type metabolites, probably formed through reaction with hydroxyl radicals. Ab initio molecular orbital calculations predicted radical attack mainly at C
2 of the quinolone moiety. This is the carbon atom with the largest Fukui function. Reaction with ozone is expected to mainly occur at
N
4
′
, characterized by the largest negative charge.
•Due to stress at weaning, piglets often receive antibiotics to treat diarrhea and health problems.•There are potential cross-resistance problems; therefore, alternative nutritional concepts for ...weaned piglets are needed.•Potential dietary feed additives identified in this review could contribute to a reduction in dependency on antibiotics.
This meta-analysis evaluated the use of potential dietary feed additives (pDFA) with antibacterial effects and their impact on the perfomance of weaned piglets. Twenty-three peer-reviewed in vivo studies, comprising 50 trials, were identified between January 2010 and January 2017. The pDFA in these studies could be grouped in 5 classes: antimicrobial peptides, chitosan, lysozyme, medium chain fatty acids/ triglycerides and plant extracts. Mixed-effect meta-analyses with type of pDFA as fixed effect were performed for the growth parameters ‘average daily gain’ (ADG) and ‘feed conversion ratio’ (FCR), which are the two most important and used economic performance parameters for farmers.
For each class of pDFA, results of the meta-analysis showed significantly higher average daily gain in the group with pDFA compared to the negative control group, while no significant difference with the positive control group was observed. Furthermore, a positive effect on FCR was found, i.e. significantly less feed was needed to gain 1 kg of body weight in the group with pDFA compared to the negative control group. No significant differences with positive control groups were observed for each class of pDFA, except for plant extracts, where the FCR was also significantly reduced in the treatment group. These results suggest that pDFA could reduce the use of antimicrobials without significant negative effects on performance indicators.
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