Assessing the role of environmental factors on Baltic cod recruitment, a complex adaptive system emergent property

For decades, fish recruitment has been a subject of intensive research with stock–recruitment models commonly used for recruitment prediction often only explaining a small fraction of the inter-annual recruitment variation. The use of environmental information to improve our ability to predict recruitment, could contribute considerably to fisheries management. However, the problem remains difficult because the mechanisms behind such complex relationships are often poorly understood; this in turn, makes it difficult to determine the forecast estimation robustness, leading to the failure of some relationships when new data become available. The utility of machine learning algorithms such as artificial neural networks (ANNs) for solving complex problems has been demonstrated in aquatic studies and has led many researchers to advocate ANNs as an attractive, non-linear alternative to traditional statistical methods. The goal of this study is to design a Baltic cod recruitment model (FishANN) that can account for complex ecosystem interactions. To this end, we (1) build a quantitative model representation of the conceptual understanding of the complex ecosystem interactions driving Baltic cod recruitment dynamics, and (2) apply the model to strengthen the current capability to project future changes in Baltic cod recruitment. FishANN is demonstrated to bring multiple stressors together into one model framework and estimate the relative importance of these stressors while interpreting the complex nonlinear interactions between them. Additional requirements to further improve the current study in the future are also proposed

Mechanical thrombectomy in acute stroke – Five years of experience in Poland

Objectives Mechanical thrombectomy (MT) is not reimbursed by the Polish public health system. We present a description of 5 years of experience with MT in acute stroke in Comprehensive Stroke Centers (CSCs) in Poland. Methods and results We retrospectively analyzed the results of a structured questionnaire from 23 out of 25 identified CSCs and 22 data sets that include 61 clinical, radiological and outcome measures. Results Most of the CSCs (74%) were founded at University Hospitals and most (65.2%) work round the clock. In 78.3% of them, the working teams are composed of neurologists and neuro-radiologists. All CSCs perform CT and angio-CT before MT. In total 586 patients were subjected to MT and data from 531 of them were analyzed. Mean time laps from stroke onset to groin puncture was 250±99min. 90.3% of the studied patients had MT within 6h from stroke onset; 59.3% of them were treated with IV rt-PA prior to MT; 15.1% had IA rt-PA during MT and 4.7% – emergent stenting of a large vessel. M1 of MCA was occluded in 47.8% of cases. The Solitaire device was used in 53% of cases. Successful recanalization (TICI2b–TICI3) was achieved in 64.6% of cases and 53.4% of patients did not experience hemorrhagic transformation. Clinical improvement on discharge was noticed in 53.7% of cases, futile recanalization – in 30.7%, mRS of 0–2 – in 31.4% and mRS of 6 in 22% of cases. Conclusion Our results can help harmonize standards for MT in Poland according to international guidelines

Control Mechanisms in Nutrient Dynamics and Biological Productivity in the Eastern Equatorial Pacific Ocean

The equatorial Pacific has been recognized for decades as a major region of enhanced biological production which is due to persistently cool waters of equatorial upwelling. Early observations of unused nitrate and relatively low phytoplankton biomass in the equatorial Pacific led to the question of Why isn\u27t the equatorial Pacific greener? The main objective of my dissertation work is to unravel the roles and interactions of regulatory mechanisms in the eastern equatorial Pacific Ocean, challenged and inspired by the progress represented by the JGOFS EqPac (1992) and the Equatorial Biocomplexity (2004 and 2005) projects, as well as some recent development of modeling capabilities. In this study, I use a box model approach to construct a complete iron (Fe) budget in the equatorial Pacific, which reveals the importance of upwelling in supplying this growth-limiting nutrient. Moreover, through coupled physical and biological model simulations for 2004 and 2005, I reveal the important role that tropical instability waves play in regulating supply and diatom uptake of another limiting nutrient: silicon (Si). Extending the model simulations from 1991 to 2009, I then examine the role of El Nino Southern Oscillation in controlling interannual to decadal variability in nutrient dynamics and biological productivity in the eastern equatorial Pacifc. The results of this dissertation work point at a surprising resilience of the biological system to long-term changes in physical environment in the Pacific Ocean. I speculate that Si and Fe co-limitation and a strong grazing pressure create a well-balanced ecosystem where the diatom population cannot thrive, thus explaining why the equatorial Pacific is not greener

Mechanical thrombectomy in acute stroke : five years of experience in Poland

Objectives: Mechanical thrombectomy (MT) is not reimbursed by the Polish public health system. We present a description of 5 years of experience with MT in acute stroke in Comprehensive Stroke Centers (CSCs) in Poland. Methods and results: We retrospectively analyzed the results of a structured questionnaire from 23 out of 25 identified CSCs and 22 data sets that include 61 clinical, radiological and outcome measures. Results: Most of the CSCs (74%) were founded at University Hospitals and most (65.2%) work round the clock. In 78.3% of them, the working teams are composed of neurologists and neuro-radiologists. All CSCs perform CT and angio-CT before MT. In total 586 patients were subjected to MT and data from 531 of them were analyzed. Mean time laps from stroke onset to groin puncture was 250 99 min. 90.3% of the studied patients had MT within 6 h from stroke onset; 59.3% of them were treated with IV rt-PA prior to MT; 15.1% had IA rt-PA during MT and 4.7% - emergent stenting of a large vessel. M1 of MCA was occluded in 47.8% of cases. The Solitaire device was used in 53% of cases. Successful recanalization (TICI2b–TICI3) was achieved in 64.6% of cases and 53.4% of patients did not experience hemorrhagic transformation. Clinical improvement on discharge was noticed in 53.7% of cases, futile recanalization - in 30.7%, mRS of 0–2 - in 31.4% and mRS of 6 in 22% of cases. Conclusion: Our results can help harmonize standards for MT in Poland according to international guideline