Remote sensing analysis of natural oil and gas seeps on the continental slope of the northern Gulf of Mexico

Natural hydrocarbon seeps harbor distinctive geological, chemical, and biological features in the marine environment. This thesis verified remote sensing signatures of seeps using in-situ observation and repeated collections of satellite imagery. Bubble streams in the Gulf of Mexico water column from four natural seep sites on the upper continental slope were imaged by a side-scan sonar, which was operated from a submarine near the seafloor, and by acoustic profilers, which were operated from surface ships. These data were correlated with sea surface slicks imaged by Synthetic Aperture Radar (SAR) on the RADARSAT satellite. Comparing non-oily bubble streams from rapidly venting mud volcanoes with oily bubble streams from shallow deposits of gas hydrate showed that they produced notably different signatures. Non-oily bubbles produced high backscatter on the side-scan sonar records, but were difficult to detect with the acoustic profilers. Oily bubbles from hydrate deposits produced acoustic shadows on the side-scan sonar records. The oily bubbles generated clear signatures extending from the seafloor to the near surface on the acoustic profile records. RADARSAT SAR images verified the presence of surface oil slicks over the hydrate deposits, but not over the mud volcanoes. This indicates that SAR imagery will not be able to capture every oil and gas seep in a region because non-oily bubble streams do not create surface oil slicks. A total of 113 natural oily seep sources were identified based on surface slicks in eleven SAR images collected over the northern continental slope. A persistence analysis verified that SAR is a dependable tool for capturing oil slicks because 93.5% of the slick sources identified in the 2001 images were corroborated with slicks in the 2002 images. The sources ranged in depth from 100 to 2000 m and 79% of the sources were in 900 meters or greater of water. Seventy-six percent of the seep sources were associated with salt less than 1500 m below the seafloor and none of the sources were located in the bottom of salt withdrawal basins. Geographical Information Systems (GIS) proved to be a useful tool in these analyses

Case report: "Proust phenomenon" after right posterior cerebral artery occlusion.

Odors evoking vivid and intensely felt autobiographical memories are known as the "Proust phenomenon," delineating the particularity of olfaction in being more effective with eliciting emotional memories than other sensory modalities. The phenomenon has been described extensively in healthy participants as well as in patients during pre-epilepsy surgery evaluation after focal stimulation of the amygdalae and post-traumatic stress disorder (PTSD). In this study, we provide the inaugural description of aversive odor-evoked autobiographical memories after stroke in the right hippocampal, parahippocampal, and thalamic nuclei. As potential underlying neural signatures of the phenomenon, we discuss the disinhibition of limbic circuits and impaired communication between the major networks, such as saliency, central executive, and default mode network

Case report: “Proust phenomenon” after right posterior cerebral artery occlusion

Odors evoking vivid and intensely felt autobiographical memories are known as the “Proust phenomenon,” delineating the particularity of olfaction in being more effective with eliciting emotional memories than other sensory modalities. The phenomenon has been described extensively in healthy participants as well as in patients during pre-epilepsy surgery evaluation after focal stimulation of the amygdalae and post-traumatic stress disorder (PTSD). In this study, we provide the inaugural description of aversive odor-evoked autobiographical memories after stroke in the right hippocampal, parahippocampal, and thalamic nuclei. As potential underlying neural signatures of the phenomenon, we discuss the disinhibition of limbic circuits and impaired communication between the major networks, such as saliency, central executive, and default mode network

When the lens is too wide: The political consequences of the visual dehumanization of refugees

Photojournalistic images shape our understanding of sociopolitical events. How humans are depicted in images may have far-reaching consequences for our attitudes towards them. Social psychology has shown how the visualization of an ‘identifiable victim effect’ can elicit empathic responses. However, images of identifiable victims in the media are the exception rather than the norm. In the context of the Syrian refugee crisis, the majority of images in Western media depicted refugees as large unidentifiable groups. While the effects of the visual depiction of single individuals are well-known, the ways in which the visual framing of large groups operates, and its social and political consequences, remain unknown. We here focus on the visual depiction of refugees to understand how exposure to the dominant visual framing used in the media, depicting them in large groups of faceless individuals, affects their dehumanization and sets off political consequences. To that end we brought together insights from social psychology, social sciences and the humanities to test a range of hypotheses using methods from social and political psychology in 10 studies with the participation of 3951 European citizens. Seeing images of large groups resulted in greater implicit dehumanization compared with images depicting refugees in small groups. Images of large groups are also explicitly rated as more dehumanizing, and when coupled with meta-data such as newspaper headlines, images continue to play a significant and independent role on how (de)humanizing we perceive such news coverage to be. Moreover, after viewing images of large groups, participants showed increased preference for more dominant and less trustworthy-looking political leaders and supported fewer pro-refugee policies and more anti-refugee policies. In terms of a mechanistic understanding of these effects, the extent to which participants felt pity for refugees depicted in large groups as opposed to small groups mediated the effect of visual framing on the choice of a more authoritarian-looking leader. What we see in the media and how it is shown not only has consequences for the ways in which we relate to other human beings and our behaviour towards them but, ultimately, for the functioning of our political systems

Clinical Evaluation of a Quantitative Imaging Biomarker Supporting Radiological Assessment of Hippocampal Sclerosis.

OBJECTIVE To evaluate the influence of quantitative reports (QReports) on the radiological assessment of hippocampal sclerosis (HS) from MRI of patients with epilepsy in a setting mimicking clinical reality. METHODS The study included 40 patients with epilepsy, among them 20 with structural abnormalities in the mesial temporal lobe (13 with HS). Six raters blinded to the diagnosis assessed the 3T MRI in two rounds, first using MRI only and later with both MRI and the QReport. Results were evaluated using inter-rater agreement (Fleiss' kappa [Formula: see text]) and comparison with a consensus of two radiological experts derived from clinical and imaging data, including 7T MRI. RESULTS For the primary outcome, diagnosis of HS, the mean accuracy of the raters improved from 77.5% with MRI only to 86.3% with the additional QReport (effect size [Formula: see text]). Inter-rater agreement increased from [Formula: see text] to [Formula: see text]. Five of the six raters reached higher accuracies, and all reported higher confidence when using the QReports. CONCLUSION In this pre-use clinical evaluation study, we demonstrated clinical feasibility and usefulness as well as the potential impact of a previously suggested imaging biomarker for radiological assessment of HS

Visual exploratory behaviour of normal subjects and patients with homonymous hemianopia: analysis with driving simulator

Einleitung: Bei Normalprobanden wird angenommen, dass mit zunehmendem Alter die anhaltende räumliche Aufmerksamkeit und schnelle Reaktionsfähigkeit auf periphere Reize abnimmt (Crundall et al., 2002; Rogé et al., 2004). Patienten mit homonymer Hemianopsie (HH) berichten im Alltag unterschiedlich mit ihrer Gesichtsfeldeinschränkung umzugehen. In Laborsituationen konnten visuelle Explorationsmuster beschrieben werden (Zihl, 1995), mithilfe derer die Patienten ihr Defizit kompensierten. Methodik: Wir untersuchten insgesamt 73 Normalprobanden unterschiedlichen Alters und 14 Patienten mit HH in einem Fahrsimulator–Versuchsaufbau. Augen–und Kopfbewegungen wurden dabei mittels einer Kopf–montierten Augenbewegungs–Kamera aufgezeichnet (Hamel et al., 2012). Die Studienteilnehmer sollten während des Fahrens von Strecken unterschiedlicher Komplexität so schnell wie möglich auf aufkommende Hindernisse verschiedener Ekzentrizitäten (peripher vs. zentral) reagieren. Ergebnisse: Ältere Probanden führten mehr Kopfbewegungen durch, was ihre Blickamplitude erweiterte, videospielerfahrene Probanden zeigten u.a. eine breitere Varianz an Fixationen auf der Horizontalen, was ihnen zu einer schnelleren Detektionsleistung auf peripher gelegene Objekte verhalf. Wir konnten zeigen, dass „high performer“ (HP) mit HH eine deutlich breitere Varianz an Augenbewegungen auf der Leinwand durchführten, als „low performer“ (LP). Dies ermöglichte den HP eine effiziente Kompensation. LP schätzten auf Nachfrage ihre Fahrleistung dennoch als gut ein. Schlussfolgerung: Unser Versuchsaufbau ermöglicht visuelles Explorationsverhalten von Normalprobanden und Patienten innerhalb eines dynamischen und realitätsnahen Settings zu erheben. Einen beginnenden, altersrelevanten visuoperzeptiven Funktionsabbau konnten wir in unserem Kollektiv nicht objektivieren. Aufgrund des maßgeblichen Einflusses der Videospielerfahrung empfehlen wir diese als Variable in zukünftige Simulatorstudien miteinzubeziehen. Wir konnten relevante Unterschiede bezüglich der Augenbewegungsparameter zwischen den Patientengruppen und den Normalprobanden aufzeigen. Inwiefern unser Studienaufbau als mögliches Augenbewegungsbasiertes Rehabilitationsverfahren benutzt werden kann, muss in kommenden Untersuchungen evaluiert werden.Introduction: It is discussed, that with increasing age the capacity of fast reaction towards upcoming obstacles as well as the visuospatial attention decreases in situations with high workload (Crundall et al, 2002, Rogé et al. 2004). Patients with homonymous hemianopia (HH) report to handle their visual field deficit quite differently after an infarction of the posterior cerebry artery (PCA). Despite similar deficits one can distinguish in laboratory testing situations different visual scan patterns (Zihl, 1995) allowing them to compensate for their deficit. How do healthy persons of varying age and patients with HH assure the coherence of their visuospatial perception in a dynamic and complex natural–scene setting? Methods: We measured in total 73 healthy subjects of varying age and 14 patients with HH in our driving simulator paradigm. Eye–and head movements were recorded via a head–mounted Eye–Tracker. The participants were asked to detect as fast as possible towards upcoming obstacles from two eccentricities (peripheral vs. central) while driving scenarios of different road complexities. Results: Healthy subjects did not differ regarding age in the use of eye–movements. Older participants executed more head movements, in order to enlarge their field of view. Participants with an extensive experience of animated video games, showed a wider spread of fixations within the screen and detected faster manually towards upcoming obstacles. We could show that high performing patients (HP) had a wider spread of fixations within the screen, in comparison to low performing patients (LP). This assured them an efficient compensatory behavior in task. When asked to rate, LP rated their performance as good. Conclusion: Our study paradigm enables us to assess reliably and in a standardized manner the visual exploratory behavior of healthy subjects as well as patients with visual field defect. We couldn’t find an age effect that would suggest early visuoperceptual decline in our collective. Nevertheless, the level of videogame experience being highly correlated with increasing age, we suggest accounting for both variables in future simulation studies. We could show relevant differences regarding the use of eye movements towards the blind field within the patient group and in comparison to healthy subjects. For both patient subgroups, further investigations of the individual scanning patterns are needed in order to better understand the underlying cognitive mechanisms as well as to evaluate the gain of a potential eye–movements based rehabilitation task within our experimental setup

Self-Portraits

A series of two experiments investigating 'self-portraits' - the visualisation of people's mental images of their own facial and bodily appearance

The Self in the Mind’s Eye: Reverse-correlating one’s self reveals how psychological beliefs and attitudes shape our body-image

How do we ‘see’ ourselves in our mind’s eye? The question of how we represent our self has been at the centre of cultural practices across centuries, as the long tradition of self-portraits attests, and at the centre of our understanding of mental health issues such as body-image disorders. By implementing a reverse-correlation technique to measure self-representations, we were able to visualise participants’ mental images of both their faces and their body-shapes in a data-driven, unconstrained way, allowing us to visually depict how the self is ‘seen’ in our minds. Our technique was successful, revealing ‘self-portraits’ which were strikingly accurate. However, importantly, we discovered that the facial features of the self-portraits also contained ‘clues’ to each person’s self-reported personality traits, which were reliably detected by external observers. Finally, the higher the participants’ self-esteem with regards to social interactions, the more accurate and true-to-life their self-portraits were. Unlike the facial self-portraits, the body-shape portraits had negligible direct relationships with individuals’ actual body shape, but as with faces, they were significantly influenced by people’s beliefs and emotions; individuals with lower body self-esteem visually represented their bodies as wider. Together, our findings show how psychological beliefs and attitudes about one’s self bias the perceptual representation of one’s appearance, and provide a unique revealing window to into the internal mental representation of one’s self, with important implications for mental health and visual culture

When the lens is too wide: the political consequences of the visual dehumanization of refugees

Photojournalistic images shape our understanding of sociopolitical events. How humans are depicted in images may have far-reaching consequences for our attitudes towards them. Here, we focus on the visual depiction of refugees to understand how exposure to the dominant visual framing used in the media, depicting them in large groups of faceless individuals, affects their dehumanization and sets off political consequences. Seeing images of large groups resulted in greater implicit dehumanization compared with images depicting small groups. Moreover, after viewing images of large groups, participants showed increased preference for more dominant, less trustworthy political leaders and supported less pro-refugee policies and more anti-refugee policies. Lastly, the extent to which participants felt reduced pity for images depicting large groups mediated the effect of visual framing on the choice of more authoritarian leaders. What we see in the media and how it is shown has attitudinal, behavioural as well as political consequences