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Adaptive strategies of sponges to deoxygenated oceans
Get PDFOcean deoxygenation is one of the major consequences of climatechange. In coastal waters, this process can be exacerbated byeutrophication, which is contributing to an alarming increase in the so called“dead zones” globally. Despite its severity, the effect of reduceddissolved oxygen has only been studied for a very limited number oforganisms, compared to other climate change impacts such as oceanacidification and warming. Here we experimentally assessed theresponse of sponges to moderate and severe simulated hypoxic events.We ran three laboratory experiments on four species from two differenttemperate oceans (NE Atlantic and SW Pacific). Sponges were exposedto a total of five hypoxic treatments, with increasing severity (3.3, 1.6,0.5, 0.4 and 0.13 mg O2 L-1, over 7–12 days). We found that spongesare generally very tolerant of hypoxia. All the sponges survived in theexperimental conditions, except Polymastia croceus, which showedsignificant mortality at the lowest oxygen concentration (0.13 mg O2 L-1, lethal median time: 286 h). In all species except Suberites carnosus,hypoxic conditions do not significantly affect respiration rate down to 0.4mg O2 L-1, showing that sponges can uptake oxygen at very lowconcentrations in the surrounding environment. Importantly, spongesdisplayed species-specific phenotypic modifications in response to thehypoxic treatments, including physiological, morphological, andbehavioural changes. This phenotypic plasticity likely represents anadaptive strategy to live in reduced or low oxygen water. Our resultsalso show that a single sponge species (i.e., Suberites australiensis) candisplay different strategies at different oxygen concentrations. Comparedto other sessile organisms, sponges generally showed higher tolerance tohypoxia, suggesting that sponges could be favoured and survive infuture deoxygenated oceans
Impossible reconciliation? The representation of traumatic memories in<i> La meilleure façon de s’aimer</i> (2012) by Akli Tadjer
Get PDFThis article analyzes the representation of traumatic memories of Algeria in the novel La meilleure façon de s’aimer (2012) by Akli Tadjer, a French writer of Algerian origin. While recent decades have seen a more regular engagement in the French political and public spheres with the past shared by France and Algeria, this confrontation with the past is not a straightforward process. As demonstrated by the reactions to the state-commissioned report on France’s colonial past in Algeria, written and submitted by the renowned historian Benjamin Stora in 2021, constructing a singular shared narrative of the past is fraught and laced with difficulty. Drawing on theories of trauma and the representation of traumatic experiences, this article examines the extent to which reconciliation of the past is possible, through a close textual analysis of the representation of memories of Algeria in Tadjer’s text. It will be shown how memories of Algeria are depicted in the novel as incomplete, fractured, and characterized by a difficult transmission from generation to generation. Thus, rather than the simplicity denoted by the notion of reconciliation, La meilleure façon de s’aimer highlights the complexity of communicating traumatic pasts and reiterates that the “unspeakable and the unknown” constitute intrinsic elements of any representation or narrative of such pasts. This does not mean that remembering the past is a futile task, but that recognizing conflict, silence, and forgetting as defining characteristics of the Franco-Algerian past provides a more productive exploration of the past than the potentially facile notion of reconciliation. Furthermore, the article will show how Tadjer’s text reflects the need for multiple, overlaying narratives in order to provide a more inclusive, wide-ranging, though perhaps never complete, account of the past
A qualitative systematic review of the role of families in supporting communication in people with dementia.
Get PDFCognitive-communication difficulties are often associated with dementia and can impact a person’s ability to participate in meaningful conversations. This can create challenges to families, reflecting the reality that people living with dementia rarely have just one regular conversation partner, but interact with multiple family members. To date, there is limited evidence of the impact of changes in communication patterns in families. A family systems approach, with foundations in psychology, can be used to explore the impact of communication difficulties on multiple different family members, including the person living with dementia and potential coping strategies used by individuals, together with the family as a whole. A systematic review of primary qualitative research was conducted to identify and examine research exploring communication and interaction within families living with dementia. Studies were identified through a comprehensive search of major databases and the full text articles were subject to a quality appraisal. We conducted a thematic analysis on the literature identified to consider the role of families in supporting communication for people with dementia. The searches identified 814 possible articles for screening against the eligibility criteria. Nine articles were included in the final review. Three major themes emerged from the analysis of the included studies. 1) ‘Identities changing’ reflected how interactions within the family systems impacted on identities, 2) ‘Loss’ reflected the grief experienced by families due to changes in communication. 3) ‘Developing communication strategies’ highlighted strategies and approaches that families affected by dementia may use organically to engage in meaningful interactions and maintain connection. Only one study explicitly used a family systems approach to understand how families manage the changes in interaction resulting from dementia. The findings may usefully inform the clinical practice of Speech and Language Therapists in terms of communication strategies and coping mechanisms that may be advised to facilitate connection in families living with dementia. Further research utilising a family systems approach to exploring communication in dementia may help to support the implementation of family-centred practice as recommended in policy.<br/
Use of fast realistic simulations on GPU to extract CAD models from microtomographic data in the presence of strong CT artefacts
Get PDFThe presence of strong imaging artefacts in microtomographic X-ray data makes the CAD modelling process difficult to carry out. As an alternative to traditional image segmentation techniques, we propose to register the CAD models by deploying a realistic X-ray simulation on GPU in an optimisation framework. A user study was also conducted to compare the measurements made manually by a cohort of volunteers and those produced with our framework. Our implementation relies on open source software only. We numerically modelled the real experiment, taking into account geometrical properties as well as beam hardening, impulse response of the detector, phase contrast, and photon noise. Parameters of the overall model are then optimised so that X-ray projections of the registered the CAD models match the projections from an actual experiment. It appeared that manual measurements can be variable and subject to bias whereas our framework produced more reliable results. The features seen in the real CT image, including artefacts, were accurately replicated in the CT image reconstructed from the simulated data after registration: (i) linear attenuation coefficients are comparable for all the materials, (ii) geometrical properties are accurately recovered, and (iii) simulated images reproduce observed experimental artefacts. We showed that the choice of objective function is crucial to produce high fidelity results. We also demonstrated how to automatically produce CAD models as an optimisation problem, producing a high cross-correlation between the experimental CT slice and the simulated CT slice. These results pave the way towards the use of fast realistic simulation for accurate CAD modelling in tomographic X-ray data
Chronic neuropsychiatric sequelae of SARS-CoV-2:Protocol and methods from the Alzheimer's Association Global Consortium
Get PDFIntroduction: Coronavirus disease 2019 (COVID-19) has caused >3.5 million deaths worldwide and affected >160 million people. At least twice as many have been infected but remained asymptomatic or minimally symptomatic. COVID-19 includes central nervous system manifestations mediated by inflammation and cerebrovascular, anoxic, and/or viral neurotoxicity mechanisms. More than one third of patients with COVID-19 develop neurologic problems during the acute phase of the illness, including loss of sense of smell or taste, seizures, and stroke. Damage or functional changes to the brain may result in chronic sequelae. The risk of incident cognitive and neuropsychiatric complications appears independent from the severity of the original pulmonary illness. It behooves the scientific and medical community to attempt to understand the molecular and/or systemic factors linking COVID-19 to neurologic illness, both short and long term.Methods: This article describes what is known so far in terms of links among COVID-19, the brain, neurological symptoms, and Alzheimer's disease (AD) and related dementias. We focus on risk factors and possible molecular, inflammatory, and viral mechanisms underlying neurological injury. We also provide a comprehensive description of the Alzheimer's Association Consortium on Chronic Neuropsychiatric Sequelae of SARS-CoV-2 infection (CNS SC2) harmonized methodology to address these questions using a worldwide network of researchers and institutions.Results: Successful harmonization of designs and methods was achieved through a consensus process initially fragmented by specific interest groups (epidemiology, clinical assessments, cognitive evaluation, biomarkers, and neuroimaging). Conclusions from subcommittees were presented to the whole group and discussed extensively. Presently data collection is ongoing at 19 sites in 12 countries representing Asia, Africa, the Americas, and Europe.Discussion: The Alzheimer's Association Global Consortium harmonized methodology is proposed as a model to study long-term neurocognitive sequelae of SARS-CoV-2 infection.Key Points: The following review describes what is known so far in terms of molecular and epidemiological links among COVID-19, the brain, neurological symptoms, and AD and related dementias (ADRD)The primary objective of this large-scale collaboration is to clarify the pathogenesis of ADRD and to advance our understanding of the impact of a neurotropic virus on the long-term risk of cognitive decline and other CNS sequelae. No available evidence supports the notion that cognitive impairment after SARS-CoV-2 infection is a form of dementia (ADRD or otherwise). The longitudinal methodologies espoused by the consortium are intended to provide data to answer this question as clearly as possible controlling for possible confounders. Our specific hypothesis is that SARS-CoV-2 triggers ADRD-like pathology following the extended olfactory cortical network (EOCN) in older individuals with specific genetic susceptibility.The proposed harmonization strategies and flexible study designs offer the possibility to include large samples of under-represented racial and ethnic groups, creating a rich set of harmonized cohorts for future studies of the pathophysiology, determinants, long-term consequences, and trends in cognitive aging, ADRD, and vascular disease.We provide a framework for current and future studies to be carried out within the Consortium. and offers a "green paper" to the research community with a very broad, global base of support, on tools suitable for low- and middle-income countries aimed to compare and combine future longitudinal data on the topic.The Consortium proposes a combination of design and statistical methods as a means of approaching causal inference of the COVID-19 neuropsychiatric sequelae. We expect that deep phenotyping of neuropsychiatric sequelae may provide a series of candidate syndromes with phenomenological and biological characterization that can be further explored. By generating high-quality harmonized data across sites we aim to capture both descriptive and, where possible, causal associations.</p
‘More than an industrial boon’:Press coverage of Trawsfynydd power station’s construction, 1955-1965
Get PDFNuclear power generation has grown as an area of historical interest in recent years. While technological development has often interested historians of science, the impact of power stations on the natural landscape in specific localities has received insufficient attention. Much historical writing has neglected how the construction of nuclear power stations impacted the lives, routines, and prospects of local people upon rural north-west Wales. Both Trawsfynydd and Wylfa, the two stations constructed in the region, shaped employment opportunities and demography of the counties of Merionethshire and Anglesey (now Gwynedd and Ynŷs Mon). Recent coverage of nuclear power has been predominantly national in scope. It receives limited mentions in the major, modern Welsh history texts. Even fewer localised studies exist, particularly regarding north Wales. Primarily, they are present in political history studies of the area and are seen as attempts to reinvigorate a local economy impacted by the decline of traditional industries (slate, agriculture etc.), and this was deemed a failure. Rather, most published and unpublished research on north Wales and nuclear power has placed it either a national, political framework or a localised, high political context, in which atomic generation is a peripheral topic of discussion. Yet local parliamentarians were focused on the process of securing nuclear power stations to alleviate pressures catalysed by economic, social and cultural change. What is missing from existing studies is a broader understanding of how and why the power stations were constructed in their locations, the processes which created them and their impact on the local environment