1,721,006 research outputs found
The epidemiology of the phenomenon of not recognized newborns and the role of the general practitioner in the prevention of mother-infant attachment disorders
No full textDiscontinuous dynamics in North Sea cod Gadus morhua caused by ecosystem change
Get PDFMarine ecosystems worldwide experience abrupt changes and regime shifts in structure and functioning due to the interacting effects of multiple stressors. North Sea cod Gadus morhua is a key example of a species being strongly overexploited for decades, causing an abrupt stock decrease below scientifically advised sustainable levels. Despite reductions in fishing pressure in recent years, populations of North Sea cod have not yet recovered. Why recovery is hindered and especially how ecosystem dynamics interacted with fishing to create a stable low cod stock is an open question. Here, we sequentially apply change point and principle component analyses as well as stochastic cusp modelling to a long-term time series (1963−2018) to show that North Sea cod recovery is limited due to an interaction of fishing pressure, internal stock dynamics and external environmental changes. We found that cod biomass experienced nonlinear, discontinuous dynamics, given the interaction of fishing pressure and climate change-induced increases in temperatures, wind magnitude and the North Atlantic Oscillation. Our results further demonstrate discontinuity in cod biomass due to low recruitment caused by a discontinuous relationship between stock biomass and environmental changes characterized by climate and zooplankton variables. Our study indicates that climate-induced changes in the environment have trapped North Sea cod in a depleted state, limiting the probability that the population will regain its role as a main target species for fisheries. Hence, we highlight the importance of incorporating discontinuous dynamics in fisheries management approaches to achieve sustainable exploitation levels and to identify thresholds of drivers to favour policies to prevent regime shifts
Resilience assessment in complex natural systems
Get PDFEcological resilience is the capability of an ecosystem to maintain the same structure and function and avoid crossing catastrophic tipping points (i.e. undergoing irreversible regime shifts). While fundamental for management, concrete ways to estimate and interpret resilience in real ecosystems are still lacking. Here, we develop an empirical approach to estimate resilience based on the stochastic cusp model derived from catastrophe theory. The cusp model models tipping points derived from a cusp bifurcation. We extend cusp in order to identify the presence of stable and unstable states in complex natural systems. Our Cusp Resilience Assessment (CUSPRA) has three characteristics: (i) it provides estimates on how likely a system is to cross a tipping point (in the form of a cusp bifurcation) characterized by hysteresis, (ii) it assesses resilience in relation to multiple external drivers and (iii) it produces straightforward results for ecosystem-based management. We validate our approach using simulated data and demonstrate its application using empirical time series of an Atlantic cod population and marine ecosystems in the North Sea and the Mediterranean Sea. We show that Cusp Resilience Assessment is a powerful method to empirically estimate resilience in support of a sustainable management of our constantly adapting ecosystems under global climate change
Prophylaxis of infection with intravenous immunoglobulins plus antibiotic for patients at risk for sepsis undergoing surgery for colorectal cancer: results of a randomized, multicenter clinical trial.
No full textBACKGROUND: The results of a randomized, multicenter clinical trial with
perioperative short-term antibiotic plus intravenous immunoglobulins (IVIG + A)
versus antibiotic alone (A) for prevention of postoperative infections in
patients at risk for sepsis undergoing surgery for colorectal cancer are
presented.
METHODS: The patients at risk for sepsis were selected by an original
multiparametric test based on delayed-hypersensitivity skin testing and serum
protein electrophoretic subfractions. This screening had shown 76% positive
predictability in a previous validation assessment. Eighty patients at risk for
sepsis were selected prospectively from 210 patients undergoing surgery for
colorectal cancer; 43 patients were randomly assigned to the IVIG + A group and
37 to the A group. IVIG was administered on the day before operation, on the
first and fifth postoperative days.
RESULTS: There was a clear-cut reduction of postoperative infections in the IVIG
+ A group: 21 infections in 20 patients versus 37 infections in 29 patients in
the A group (p less than 0.004). With regard to serum immunoglobulin (Ig) G
monitoring, basal IgG levels were significantly lower in patients given IVIG + A
who had postsurgical infections (p less than 0.005) compared with patients with a
regular outcome, whereas the same was not true in the A group of patients.
CONCLUSIONS: A significant decrease (p less than 0.001) of postoperative IgG was
evidenced in the A group of patients who had infections as opposed to a
significant increase (p less than 0.001) of postoperative IgG in IVIG + A
patients with a normal outcome
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Regime shift dynamics, tipping points and the success of fisheries management
Get PDFRecovery of depleted fish stocks is an important goal for fisheries management and crucial to sustain important ecosystem functions as well as global food security. Successful recovery requires adjusting fishing mortality to stock productivity but can be prevented or inhibited by additional anthropogenic impacts such as climate change. Despite management measures to recover fish stocks being in place in legislations such as the European Union ́s Common Fisheries Policy (CFP), recovery can be hindered by the occurrence of regime shift dynamics. Such non-linear discontinuous dynamics imply tipping points and bear the characteristics of abrupt change, hysteresis and non-stationary functional relationships. We here used the recent reform of the CFP as a natural experiment to investigate the existence of regime shift dynamics and its potential effects on the recovery potential on six strongly fished or even depleted commercial fish stocks in the North Sea. Using a set of statistical approaches we show that regime shift dynamics exist in all six fish stocks as a response to changes in fishing pressure and temperature. Our results furthermore demonstrate the context-dependence of such dynamics and hence the ability of management measures to rebuild depleted fish stocks, leading to either failed recovery or positive tipping
Immunoprophylaxis in "septic risk" patients undergoing surgery for gastrointestinal cancer. Results of a randomized, multicenter clinical trial.
No full textAbstract
The results of a randomized, multicenter clinical trial of immunoprophylaxis of post-operative infections with intravenous Immunoglobulins (IVIG) (Sandoglobulin) in "septic-risk" patients undergoing surgery for gastrointestinal cancer are presented. "Septic-risk" patients were selected by an original multiparametric test based on delayed hypersensitivity skin testing and serum protein electrophoretic sub-fractions. This screening test had shown 76% positive predictivity in a previous validation assessment. In the present study, 159 "septic-risk" patients were selected prospectively from 369 patients undergoing colo-rectal (colon) and other kinds of gastrointestinal (non-colon) oncologic surgery: 80 "septic-risk" patients were included in the colon and 79 in the non-colon group. Immunoprophylaxis with IVIG (15 g on the day prior to operation, on the 1st and 5th postoperative days) was randomly associated with antibiotic prophylaxis (cefoxitin: 2 g one hour prior to, followed by 2 g at the end of operation plus 2 g every six hours for 24 hours) in colon surgery while the prophylactic schedule in non-colon surgery was only based on random administration of IVIG, at the same dosage as in the colon group. There was a clear-cut reduction of post-operative infections both in colon and non-colon "septic-risk" patients who had IVIG prophylaxis; in the colon group, 37 and 21 infections (P < 0.004) in antibiotic (A) versus IVIG plus antibiotic (IVIG + A) subset, respectively; in the non-colon group, 33 and 19 infections (P < 0.01) in control (C) versus (IVIG) subset, respectively.(ABSTRACT TRUNCATED AT 250 WORDS
Non-linearity in stock–recruitment relationships of atlantic cod: Insights from a multi-model approach
Get PDFThe stock–recruitment relationship is the basis of any stock prediction and thus fundamental for fishery management. Traditional parametric stock–recruitment models often poorly fit empirical data, nevertheless they are still the rule in fish stock assessment procedures. We here apply a multi-model approach to predict recruitment of 20 Atlantic cod (Gadus morhua) stocks as a function of adult biomass and environmental variables. We compare the traditional Ricker model with two non-parametric approaches: (i) the stochastic cusp model from catastrophe theory and (ii) multivariate simplex projections, based on attractor state-space reconstruction. We show that the performance of each model is contingent on the historical dynamics of individual stocks, and that stocks which experienced abrupt and state-dependent dynamics are best modelled using non-parametric approaches. These dynamics are pervasive in Western stocks highlighting a geographical distinction between cod stocks, which have implications for their recovery potential. Furthermore, the addition of environmental variables always improved the models’ predictive power indicating that they should be considered in stock assessment and management routines. Using our multi-model approach, we demonstrate that we should be more flexible when modelling recruitment and tailor our approaches to the dynamical properties of each individual stock
Assessing the impact of the invasive ctenophore Mnemiopsis leidyi on artisanal fisheries in the Venice Lagoon: an interdisciplinary approach
Get PDFThe sea walnut, Mnemiopsis leidyi, has invaded and expanded throughout the whole Mediterranean Sea basin. Large blooms were recorded also in the Venice Lagoon (Italy), an ecosystem rich with biodiversity which supports multiple services, including artisanal fishery production. To investigate M. leidyi impacts on lagoon artisanal fisheries, we combined fishers' local ecological knowledge, fishery landing time series analysis, and field sampling. Firstly, we interviewed artisanal fishers to date the blooms of M. leidyi. Secondly, we analyzed long-term fishery landings records to detect whether changes in landings quantity and composition were related to the ctenophore invasion. Thirdly, we sampled catches of the lagoon fyke nets. This interdisciplinary approach overcame the weaknesses of single methodologies and allowed us to reconstruct the temporal phases of M. leidyi invasion in the Venice Lagoon. Moreover, our results indicate that the lagoon landings significantly declined with the blooms, paralleled by the increase of water temperature. Finally, we showed that the mechanical obstruction of the nets, caused by the massive ctenophore blooms, strongly impacts fishing activities. Our results are a first step in assessing the short and long-term impacts of this invasive species on lagoon ecosystems, including its socioeconomic consequences, whose better understanding is fundamental to inform mitigation and adaptation measures
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