Acute cerebral infarcts in multiple arterial territories : The Bergen NORSTROKE study

Introduction The majority of acute cerebral infarcts results from an occlusion of one single cerebral artery followed by loss of blood supply to the respective arterial territory. However, several independent arterial territories may be affected if more than one cerebral artery is occluded simultaneously. Acute cerebral infarcts in multiple arterial territories (MACI) account for 10 to 20 % of all ischemic strokes. MACI may have distinct pathophysiological and clinical features differing from acute cerebral infarct(s) in a single arterial territory (SACI). Aims In this dissertation, we sought to give a broad description of patients with MACI. The aim of the first two papers was to clarify pathophysiological mechanisms in regards to the etiology. In the third paper, we assessed short-term outcome and complications within the first week after the hospital admission. The fourth paper sheds light on the clinical manifestation on admission. Methods We used data from the Bergen NORSTROKE registry. We included only patients with acute cerebral infarct(s) (ACI) confirmed by diffusion-weighted magnetic resonance imaging (DWI-MRI) consecutively admitted to the stroke unit at Haukeland University Hospital. The first two papers are based on a cohort of 2125 patients admitted from 2006 to 2013. The last two papers are based on a cohort of 3343 patients admitted in an extended time frame from 2006 to 2016. MACI was defined as more than one non-continuous ischemic lesion in more than one arterial cerebral territory; either left and/or right carotid artery territory and/or basilar artery territory. Results The proportion of patients with MACI was approximately 9% of all ACI patients. The paper-I confirmed that cardiogenic embolism (CE), as defined by TOAST criteria, is the most frequent underlying etiology of MACI. The paper-II showed a positive correlation between the time from stroke onset to MRI examination and frequency of large artery atherosclerosis (LAA)-associated MACI. There was no correlation between the time from stroke onset to MRI examination and frequency of CE- 6 associated MACI. These findings suggest that CE-associated MACI occur simultaneously as a shower of emboli, while LAA-associated MACI happens rather successively over time. The paper-III showed that patients with MACI have a worse short-term outcome within the first week after the admission compared to patients with SACI. Moreover, MACI was associated with more in-hospital complications, namely deep venous thrombosis and myocardial infarction. The paper-IV showed that 72% of patients diagnosed with MACI presented with a single-territory clinical manifestation (MACI-S) on admission. MACI-S was associated with less than five ischemic lesions on DWI-MRI, involvement of the left hemisphere, and a partial anterior cerebral infarct stroke syndrome (PACI) as defined by the Oxfordshire Community Stroke Project (OCSP) classification. This finding emphasizes the essential role of MRI examination for final diagnosis of MACI. Conclusion The data presented in this dissertation show that patients with MACI differ in many clinical aspects from patients with SACI. Our findings add new knowledge to this less documented field of stroke medicine and may help to improve the diagnostic and therapeutic approaches in these patients

Whole-ecosystem experimental manipulations of tropical forests.

Tropical forests are highly diverse systems involving extraordinary numbers of interactions between species, with each species responding in a different way to the abiotic environment. Understanding how these systems function and predicting how they respond to anthropogenic global change is extremely challenging. We argue for the necessity of 'whole-ecosystem' experimental manipulations, in which the entire ecosystem is targeted, either to reveal the functioning of the system in its natural state or to understand responses to anthropogenic impacts. We survey the current range of whole-ecosystem manipulations, which include those targeting weather and climate, nutrients, biotic interactions, human impacts, and habitat restoration. Finally we describe the unique challenges and opportunities presented by such projects and suggest directions for future experiments.This review was initiated during a symposium on ‘The effects of large scale manipulations of tropical forests on arthropod assemblages’ at the INTECOL 2013 congress, London 18–23 August 2013. T.M.F. is funded by the Australian Research Council (DP140101541), T.M.F. and R.M.E. by Yayasan Sime Darby, TMF and Y.B. by the project Biodiversity of Forest Ecosystems (CZ.1.07/2.3.00/20.0064) co-financed by the European Social Fund and the state budget of the Czech Republic, and T.M.F. Y.B. and V.N. by the Czech Science Foundation (GACR 14-32302S, 14-36098G, 14-04258S respectively). Y.B. is also supported by the Sistema Nacional de Investigacio´n of Panama. E.C.T. is supported by funds from PT SMART Research Institute and the Isaac Newton Trust, Cambridge. R.M.E. is supported by European Research Council Project number 281986. We are grateful to Maureen Fayle, Andrew Hector, Jan Leps, Scott Miller, Kalsum M. Yusah, Paul Craze, and two anonymous reviewers for advice during the drafting of the manuscript, and Jennifer Balch for additional information regarding her burning experiments.This is the final published version. It first appeared at http://www.cell.com/trends/ecology-evolution/abstract/S0169-5347%2815%2900069-5

High-speed Side-channel-protected Encryption and Authentication in Hardware

This paper describes two FPGA implementations for the encryption and authentication of data, based on the AES algorithm running in Galois/Counter mode (AES-GCM). Both architectures are protected against side-channel analysis attacks through the use of a threshold implementation (TI). The first architecture is fully unrolled and optimized for throughput. The second architecture uses a round-based structure, fits on a relatively small FPGA board, and is evaluated for side-channel attack resistance. We perform a Test Vector Leakage Assessment (TVLA), which shows no first-order leakage in the power consumption of the FPGA. To the best of our knowledge, our work is (1) the first to describe a throughput-optimized FPGA architecture of AES-GCM, protected against first-order side-channel information leakage, and (2) the first to evaluate the side-channel attack resistance of a TI-protected AES-GCM implementation

Persistent microembolic signals in the cerebral circulation on transcranial Doppler after intravenous sulfur hexafluoride microbubble infusion

BACKGROUND AND PURPOSE: Microembolic signals (MES) are detectable by transcranial Doppler monitoring and associated with increased risk of first or recurrent ischemic stroke. MES detection can also illuminate stroke etiology and the effect of prophylactic treatment. MES detection cannot accurately distinguish between stroke‐related microemboli and ultrasound contrast agents. These agents contain microbubbles and are frequently used in neuro‐ and cardiovascular diagnostics. We aimed to assess how long after contrast infusion microbubbles are detectable by transcranial Doppler monitoring. METHODS: Ten healthy volunteers received an intravenous infusion of stabilized sulfur hexafluoride microbubbles (SonoVue®) for 30 minutes. The infusion was followed by continuous unilateral Doppler monitoring (TCD‐X, Atys Medical, Soucieu‐en‐Jarrest, France) for 3.5 hours. RESULTS: MES persisted for 12 to 77 minutes (median 40.5 minutes), and the frequency tended to decrease gradually until cessation. CONCLUSIONS: None of the subjects had detectable MES for more than 77 minutes after ultrasound contrast infusion. MES detection with the intent to detect stroke‐related microemboli should wait for at least this long after completed infusion.publishedVersio

Network reorganization and breakdown of an ant-plant protection mutualism with elevation.

Both the abiotic environment and the composition of animal and plant communities change with elevation. For mutualistic species, these changes are expected to result in altered partner availability, and shifts in context-dependent benefits for partners. To test these predictions, we assessed the network structure of terrestrial ant-plant mutualists and how the benefits to plants of ant inhabitation changed with elevation in tropical forest in Papua New Guinea. At higher elevations, ant-plants were rarer, species richness of both ants and plants decreased, and the average ant or plant species interacted with fewer partners. However, networks became increasingly connected and less specialized, more than could be accounted for by reductions in ant-plant abundance. On the most common ant-plant, ants recruited less and spent less time attacking a surrogate herbivore at higher elevations, and herbivory damage increased. These changes were driven by turnover of ant species rather than by within-species shifts in protective behaviour. We speculate that reduced partner availability at higher elevations results in less specialized networks, while lower temperatures mean that even for ant-inhabited plants, benefits are reduced. Under increased abiotic stress, mutualistic networks can break down, owing to a combination of lower population sizes, and a reduction in context-dependent mutualistic benefits

Surfaces: An interdisciplinary project to understand and enhance health in the vulnerable rainforests of Papua New Guinea

Background New Guinea has the third largest tropical rainforest on Earth. However, one quarter of the forests of Papua New Guinea (PNG, New Guinea’s eastern half) have been cleared or degraded, nearly half through commercial logging.Sustainable development requires supporting good health (Sustainable Development Goal [SDG] 3) and protecting life on land (SDG 15). To remote communities in PNG with low levels of health provision, these goals can seem in conflict. Logging companies’ offer of roads and income can partly extinguish the remoteness that bars access to health services, making desire for health a driver for forest destruction and erosion of health related ecosystem services. Conservation success thus requires synergies be developed with delivery of other SDGs, particularly those pertaining to health. We aim to provide a model of integrated health and conservation in PNGs rainforests. Methods We are mapping and piloting biological, anthropological, and medical methods to address SDGs on health and biodiversity, focusing first on scabies and fungal diseases. At Wanang, team members have a long term collaboration with nine clans with unmet health needs who collectively chose to preserve their 10,000 hectare forest whilst surrounding communities allowed logging. Similar collaborations are being developed along an altitudinal transect on Mt.Wilheim (4,509m). Stage 1 of Surfaces will (i) systematically map evidence on integrated conservation and health programmes, (ii) conduct clinical examinations and rapid anthropological assessments to understand medical needs, and survey skin disease, and (iii) produce a case study of the Wanang agreement, based on interviews with participants. This will lay the foundation for a multi-year health intervention and interdisciplinary study. Findings We are in the projects’ early stages (so do not yet have findings), and would appreciate advice and suggestions of collaboration from others in the Planetary Health community. Funding Sussex Sustainability Research Programme, University of Sussex, UK. Contributions All authors have commented on multiple drafts and approved the final version of the abstract for publication. Conflicts of interest We declare we have no conflicts of interest. Acknowledgments We thank the projects partner communities; New Guinea Binatang Research Centre; and our advisory group

Contributions of paraecologists and parataxonomists to research, conservation, and social development

Citizen science has been gaining momentum in the United States and Europe, where citizens are literate and often interested in science. However, in developing countries, which have a dire need for environmental data, such programs are slow to emerge, despite the large and untapped human resources in close proximity to areas of high biodiversity and poorly known floras and faunas. Thus, we propose that the parataxonomist and paraecologist approach, which originates from citizen-based science, is well suited to rural areas in developing countries. Being a paraecologist or a parataxonomist is a vocation and entails full-time employment underpinned by extensive training, whereas citizen science involves the temporary engagement of volunteers. Both approaches have their merits depending on the context and objectives of the research. We examined 4 ongoing paraecologist or parataxonomist programs in Costa Rica, India, Papua New Guinea, and southern Africa and compared their origins, long-term objectives, implementation strategies, activities, key challenges, achievements, and implications for resident communities. The programs supported ongoing research on biodiversity assessment, monitoring, and management, and participants engaged in non-academic capacity development in these fields. The programs in Southern Africa related to specific projects, whereas the programs in Costa Rica, India, and Papua New Guinea were designed for the long term, provided sufficient funding was available. The main focus of the paraecologists' and parataxonomists' activities ranged from collection and processing of specimens (Costa Rica and Papua New Guinea) or of socioeconomic and natural science data (India and Southern Africa) to communication between scientists and residents (India and Southern Africa). As members of both the local land user and research communities, paraecologists and parataxonomists can greatly improve the flow of biodiversity information to all users, from local stakeholders to international academia