Making spatial-temporal marine ecosystem modelling better - A perspective.

Marine Ecosystem Models (MEMs) provide a deeper understanding of marine ecosystem dynamics. The United Nations Decade of Ocean Science for Sustainable Development has highlighted the need to deploy these complex mechanistic spatial-temporal models to engage policy makers and society into dialogues towards sustainably managed oceans. From our shared perspective, MEMs remain underutilized because they still lack formal validation, calibration, and uncertainty quantifications that undermines their credibility and uptake in policy arenas. We explore why these shortcomings exist and how to enable the global modelling community to increase MEMs' usefulness. We identify a clear gap between proposed solutions to assess model skills, uncertainty, and confidence and their actual systematic deployment. We attribute this gap to an underlying factor that the ecosystem modelling literature largely ignores: technical issues. We conclude by proposing a conceptual solution that is cost-effective, scalable and simple, because complex spatial-temporal marine ecosystem modelling is already complicated enough.

Emergency Hybrid Approach to Ruptured Femoral Pseudoaneurysm in HIV-positive Intravenous Drug Abusers.

BACKGROUND: Chronic traumatism of the common femoral artery due to intravenous injection in drug abusers, in association with local infections and arterial wall weakening caused by human immunodeficiency virus (HIV), can lead to the development of pseudoaneurysms (PSAs). Rupture of PSA is a dramatic event in such patients, and its correction is difficult and controversial. Most of the cases reported describe open surgical elective options, which consist in ligation, repair, or substitution of the damaged arterial segment, using when possible biological grafts. In literature, few cases describe an endovascular repair with covered stent deployment. METHODS: We present 2 cases of HIV-positive intravenous injection in drug abusers who needed emergency treatment for active bleeding in ruptured PSA of the right common femoral artery. In both cases, under general anesthesia needed for lack of patient's compliance and unstable hemodynamics, a short dissection to the distal superficial femoral artery was required. RESULTS: Then, maintaining a manual compression on the bleeding site to stop hemorrhage, we deployed a covered stent graft in the site of the arterial breakdown through a retrograde approach. CONCLUSIONS: The favorable results and progressive healing of wound and local infections persuaded us not to perform any further surgical correction. The absence of recurrences and late complications, after 3 years in the first case and 1 year in the second one, lead us to consider this hybrid endovascular approach as a valuable alternative to open surgery in HIV intravenous injection in drug abuser patients, in particularly when emergency conditions occur.

The effect of an Enhanced Recovery Program in elective retroperitoneal abdominal aortic aneurysm repair.

OBJECTIVE: Enhanced Recovery Programs (ERPs) have been introduced to accelerate postoperative recovery and are mainly focused on decreasing the surgical stress response. Limited data are available regarding the implementation of ERPs in patients who undergo abdominal aortic aneurysm (AAA) repair using the retroperitoneal approach. The aims of this study were: (1) to evaluate the implementation of an ERP in patients who underwent elective retroperitoneal AAA repair; and (2) to define independent predictors of prolonged hospital length of stay (LOS) in these patients. METHODS: This was a retrospective cohort study on 221 patients who underwent elective AAA repair via a retroperitoneal approach from 2005 through 2013 at an Italian university hospital. Patients who received surgery from 2008 through 2013 and enrolled in an ERP (n = 130) were compared with those who received surgery from 2005 through 2007 and managed with traditional perioperative care (n = 91). RESULTS: Patient characteristics were comparable between groups. Intensive care unit admissions were prevalent among patients who received traditional care vs patients in the ERP (P < .01). ERP patients had fewer major (P < .01) and minor (P = .019) complications, and mortality was similar between groups. Complete functional recovery was achieved earlier in ERP patients vs controls (P < .01). Patients in the ERP group left the hospital earlier than controls (P < .01). No readmission ≤30 days were reported in the ERP group. Age ≥65 years and being in a conventional care protocol were found to be independent predictors of prolonged hospital LOS. CONCLUSIONS: The implementation of an ERP after elective AAA repair using a retroperitoneal approach reduced postoperative intensive care unit admission, accelerated functional recovery, and decreased morbidity and LOS with no readmission ≤30 days. Age ≥65 years and conventional perioperative care were the only independent predictors of prolonged LOS.

The challenge of managing the commercial harvesting of the sea urchin Paracentrotus lividus: advanced approaches are required.

Sea urchins act as a keystone herbivore in marine coastal ecosystems, regulating macrophyte density, which offers refuge for multiple species. In the Mediterranean Sea, both the sea urchin Paracentrotus lividus and fish preying on it are highly valuable target species for artisanal fisheries. As a consequence of the interactions between fish, sea urchins and macrophyte, fishing leads to trophic disorders with detrimental consequences for biodiversity and fisheries. In Sardinia (Western Mediterranean Sea), regulations for sea urchin harvesting have been in place since the mid 90s. However, given the important ecological role of P. lividus, the single-species fishery management may fail to take into account important ecosystem interactions. Hence, a deeper understanding of population dynamics, their dependance on environmental constraints and multispecies interactions may help to achieve long-term sustainable use of this resource. This work aims to highlight how sea urchin population structure varies spatially in relation to local environmental constraints and species interactions, with implications for their management. The study area (Sinis Peninsula, West Sardinia, Italy) that includes a Marine Reserve was divided into five sectors. These display combinations of the environmental constraints influencing sea urchin population dynamics, namely type of habitat (calcareous rock, granite, basalt, patchy and continuous meadows of Posidonia oceanica), average bottom current speed and predatory fish abundance. Size-frequency distribution of sea urchins under commercial size (<5 cm diameter size) assessed during the period from 2004 to 2007, before the population collapse in 2010, were compared for sectors and types of habitat. Specific correlations between recruits (0-1 cm diameter size) and bottom current speeds and between middle-sized sea urchins (2-5 cm diameter size) and predatory fish abundance were assessed. Parameters representing habitat spatial configuration (patch density, perimeter-to-area ratio, mean patch size, largest patch index, interspersion/juxtaposition index) were calculated and their influence on sea urchin density assessed. The density of sea urchins under commercial size was significantly higher in calcareous rock and was positively and significantly influenced by the density and average size of the rocky habitat patches. Recruits were significantly abundant in rocky habitats, while they were almost absent in P. oceanica meadows. The density of middle-sized sea urchins was more abundant in calcareous rock than in basalt, granite or P. oceanica. High densities of recruits resulted significantly correlated to low values of average bottom current speed, while a negative trend between the abundance of middle-sized sea urchins and predatory fish was found. Our results point out the need to account for the environmental constraints influencing local sea urchin density in fisheries management.