3,012 research outputs found
Ranking the Risks: The 10 Pathogen-Food Combinations With the Greatest Burden on Public Health
Examines food-borne pathogens with the highest disease burdens and the top ten foods most commonly contaminated by them, such as salmonella in poultry, toxoplasma in pork, and listeria in deli meats. Makes policy recommendations for improving prevention
Directional tuning of human motion adaptation as reflected by the motion VEP
AbstractMotion onset evoked visual potentials are dominated by a negativity (N2) at occipital electrodes and a positivity (P2) at the vertex. The degree of true motion processing reflected by N2 and P2 was estimated from the direction specificity of motion adaptation. Adapting stimuli moved to the right and test stimuli (random dot patterns of 26° diameter; 10% contrast; 10.5°/s velocity) moved in one of eight directions, which differed by 45°. VEPs were recorded from occipito/temporal and central sites in eight subjects. Two adaptation effects were observed for N2 (P<0.01): a global amplitude reduction by 47% and a direction-specific reduction by a further 28%. For P2, only the global effect (54%; P<0.01) was observed. The global adaptation effect could also be induced by pattern reversal and pattern-onset adaptation, i.e. stimuli containing ambiguous or very little motion energy, respectively. We conclude that at least 28% of the N2 amplitude reflects the activity of direction-specific elements, whereas P2 does not at all
Роман Ігоря Муратова “У сорочці народжений”: спроба аналізу
Ця стаття присвячена проблемі дослідження генезисних витоків та діалектиці
становлення центрального героя роману Ігоря Муратова “У сорочці народжений” Федора Коляди
та тих персонажів, які вплинули на розвиток його непересічного характеру. Відзначається високий
рівень майстерності письменника, що виражається у яскравих, індивідуальних образах. Також
розглядається короткий огляд тогочасного українського літературного процесу. Ґрунтовно
проаналізовано не тільки персонажів, але й назву роману та назви усіх п’яти розділів.
Ключові слова: час, місто, портрет, площина тексту, екстремальна ситуація, війна,
натура.Эта статья посвящается проблеме исследования генезисных истоков и диалектике
становления центрального героя романа Игоря Муратова “В сорочке рожденный” Федора Коляды
и тех персонажей, которые повлияли на развитие его незаурядного характера. Отмечается
высокий уровень мастерства писателя, что выражается в ярких, индивидуальных образах. Также
подается короткий обзор украинского литературного процесса того времени. Тщательно
проанализировано не только персонажи, а и название романа и названия всех пяти частей.
Ключевые слова: время, город, портрет, пространство текста, экстремальная ситуация,
война, натура.The article deals with the research of the genesis sources and development dialectics of Fedir
Kolyada – the main hero of the novel “Born with a silver spoon in his mouth” (“U sorotchtzi narodzheny”)
by Ihor Muratov – and other heroes, who influenced the progress of his outstanding character. The high
level writer’s skill, embodied in bright, individual images, is marked off. The paper presents a brief
review of the literary process of that period. It gives a deep analysis of not only the characters, but also
the titles of the novel and its five chapters.
Keywords: time, city, portrait, text level, extreme situation, war, nature
Primate surveys and conservation assessments
From first paragraph: The conservation of the world’s primates demands basic, but elusive and hard-to-get, information. Enormous efforts are underway to accumulate this information, and the fortuitous selection of six papers in this issue of Oryx illustrates these endeavours, each highlighting the sort of information needed. Besides a basic understanding of the diversity of primates, we need to know where they live (their geography and habitat requirements) and in what numbers. Only with such data is it possible to identify and evaluate the threats to their continued existence. Field research on particular aspects of primate ecology, behaviour, reproduction and demography provide an understanding of how primates respond to these threats and what conservation measures will be possible, effective and appropriate.Output Type: editoria
Combined multi-modal assessment of glaucomatous damage with electroretinography and optical coherence tomography/angiography
Purpose: To compare the diagnostic performance and to evaluate the interrelationship of electroretinographical and structural and vascular measures in glaucoma. Methods: For 14 eyes of 14 healthy controls and 15 eyes of 12 patients with glaucoma ranging from preperimetric to advanced stages optical coherence tomog-raphy (OCT), OCT-angiography (OCT-A), and electrophysiological measures (multifocal photopic negative response ratio [mfPhNR] and steady-state pattern electroretinogra-phy [ssPERG]) were applied to assess changes in retinal structure, microvasculature, and function, respectively. The diagnostic performance was assessed via area-under-curve (AUC) measures obtained from receiver operating characteristics analyses. The interre-lation of the different measures was assessed with correlation analyses. Results: The mfPhNR, ssPERG amplitude, parafoveal (pfVD) and peripapillary vessel density (pVD), macular ganglion cell inner plexiform layer thickness (mGCIPL) and peripapillary retinal nerve fiber layer thickness (pRNFL) were significantly reduced in glaucoma. The AUC for mfPhNR was highest among diagnostic modalities (AUC: 0.88, 95% confidence interval: 0.75–1.0, P < 0.001), albeit not statistically different from that for macular (mGCIPL: 0.76, 0.58–0.94, P < 0.05; pfVD: 0.81, 0.65–0.97, P < 0.01) or peripapillary imaging (pRNFL: 0.85, 0.70–1.0, P < 0.01; pVD: 0.82, 0.68–0.97, P < 0.01). Combined functional/vascular measures yielded the highest AUC (mfPhNR-pfVD: 0.94, 0.85–1.0, P < 0.001). The functional/structural measure correlation (mfPhNR-mGCIPL correlation coefficient [rs ]: 0.58, P = 0.001; mfPhNR-pRNFL rs: 0.66, P < 0.001) was stronger than the functional-vascular correlation (mfPhNR-pfVD rs: 0.29, P = 0.13; mfPhNR-pVD rs: 0.54, P = 0.003). Conclusions: The combination of ERG measures and OCT-A improved diagnostic performance and enhanced understanding of pathophysiology in glaucoma. Translational Relevance: Multimodal assessment of glaucoma damage improves diagnostics and monitoring of disease progression
VEP estimation of visual acuity: a systematic review
PURPOSE:Visual evoked potentials (VEPs) can be used to measure visual resolution via a spatial frequency (SF) limit as an objective estimate of visual acuity. The aim of this systematic review is to collate descriptions of the VEP SF limit in humans, healthy and disordered, and to assess how accurately and precisely VEP SF limits reflect visual acuity. METHODS:The protocol methodology followed the PRISMA statement. Multiple databases were searched using "VEP" and "acuity" and associated terms, plus hand search: titles, abstracts or full text were reviewed for eligibility. Data extracted included VEP SF limits, stimulus protocols, VEP recording and analysis techniques and correspondence with behavioural acuity for normally sighted healthy adults, typically developing infants and children, healthy adults with artificially degraded vision and patients with ophthalmic or neurological conditions. RESULTS:A total of 155 studies are included. Commonly used stimulus, recording and analysis techniques are summarised. Average healthy adult VEP SF limits vary from 15 to 40 cpd, depend on stimulus, recording and analysis techniques and are often, but not always, poorer than behavioural acuity measured either psychophysically with an identical stimulus or with a clinical acuity test. The difference between VEP SF limit and behavioural acuity is variable and strongly dependent on the VEP stimulus and choice of acuity test. VEP SF limits mature rapidly, from 1.5 to 9 cpd by the end of the first month of life to 12-20 cpd by 8-12 months, with slower improvement to 20-40 cpd by 3-5 years. VEP SF limits are much better than behavioural thresholds in the youngest, typically developing infants. This difference lessens with age and reaches equivalence between 1 and 2 years; from around 3-5 years, behavioural acuity is better than the VEP SF limit, as for adults. Healthy, artificially blurred adults had slightly better behavioural acuity than VEP SF limits across a wide range of acuities, while adults with heterogeneous ophthalmic or neurological pathologies causing reduced acuity showed a much wider and less consistent relationship. For refractive error, ocular media opacity or pathology primarily affecting the retina, VEP SF limits and behavioural acuity had a fairly consistent relationship across a wide range of acuity. This relationship was much less consistent or close for primarily macular, optic nerve or neurological conditions such as amblyopia. VEP SF limits were almost always normal in patients with non-organic visual acuity loss. CONCLUSIONS:The VEP SF limit has great utility as an objective acuity estimator, especially in pre-verbal children or patients of any age with motor or learning impairments which prevent reliable measurement of behavioural acuity. Its diagnostic power depends heavily on adequate, age-stratified, reference data, age-stratified empirical calibration with behavioural acuity, and interpretation in the light of other electrophysiological and clinical findings. Future developments could encompass faster, more objective and robust techniques such as real-time, adaptive control. REGISTRATION:International prospective register of systematic reviews PROSPERO (https://www.crd.york.ac.uk/PROSPERO/), registration number CRD42018085666
ISCEV extended protocol for VEP methods of estimation of visual acuity
The International Society for Clinical Electrophysiology of Vision (ISCEV) standard for visual evoked potentials (VEPs) describes a minimum procedure for clinical VEP testing and encourages more extensive testing. This ISCEV extended protocol is an extension to the VEP standard. It describes procedures for recording multiple VEPs to a range of sizes of pattern stimuli to establish the VEP spatial frequency limit (threshold) and for relating this limit to visual acuity
Micro-probing enables fine-grained mapping of neuronal populations using fMRI
The characterization of receptive field (RF) properties is fundamental to understanding the neural basis of sensory and cognitive behaviour. The combination of non-invasive imaging, such as fMRI, with biologically inspired neural modelling has enabled the estimation of population RFs directly in humans. However, current approaches require making numerous a priori assumptions, so these cannot reveal unpredicted properties, such as fragmented RFs or subpopulations. This is a critical limitation in studies on adaptation, pathology or reorganization. Here, we introduce micro-probing (MP), a technique for fine-grained and largely assumption free characterization of multiple pRFs within a voxel. It overcomes many limitations of current approaches by enabling detection of unexpected RF shapes, properties and subpopulations, by enhancing the spatial detail with which we analyze the data. MP is based on tiny, fixed-size, Gaussian models that efficiently sample the entire visual space and create fine-grained probe maps. Subsequently, we derived population receptive fields (pRFs) from these maps. We demonstrate the scope of our method through simulations and by mapping the visual fields of healthy participants and of a patient group with highly abnormal RFs due to a congenital pathway disorder. Without using specific stimuli or adapted models, MP mapped the bilateral pRFs characteristic of observers with albinism. In healthy observers, MP revealed that voxels may capture the activity of multiple subpopulations RFs that sample distinct regions of the visual field. Thus, MP provides a versatile framework to visualize, analyze and model, without restrictions, the diverse RFs of cortical subpopulations in health and disease.</p
Spectral Flow, Magnus Force and Mutual Friction via the Geometric Optics Limit of Andreev Reflection
The notion of spectral flow has given new insight into the motion of vortices
in superfluids and superconductors. For a BCS superconductor the spectrum of
low energy vortex core states is largely determined by the geometric optics
limit of Andreev reflection. We use this to follow the evolution of the states
when a stationary vortex is immersed in a transport supercurrent. If the core
spectrum were continuous, spectral flow would convert the momentum flowing into
the core via the Magnus effect into unbound quasiparticles --- thus allowing
the vortex to remain stationary without a pinning potential or other sink for
the inflowing momentum. The discrete nature of the states, however, leads to
Bloch oscillations which thwart the spectral flow. The momentum can escape only
via relaxation processes. Taking these into account permits a physically
transparent derivation of the mutual friction coefficients.Comment: Plain TeX, 19 pages, 5 encapsulated postscript figure
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