2,125 research outputs found
Biophysics, neural processing and robotics of the lizard ear, a highly directional sensor
No full textThe ear of lizards shows strongly directional responses with up to 40 dB differencesinsensitivitytoipsi-andcontralateralstimulation.Thedirectionality is generated by a simple principle: strong acoustical coupling of the eardrums through the large mouth cavity. Our laser vibrometry measurements show that the lizard ear is a two-input system with approximately 0 dB contralateral transmission gain in a 2 kHz frequency band. This transmission is boosted by resonances in the large, open tympanic cavities. Probably because of these resonances, the interaural delay is approximately three times larger than the arrival-time differences at the lizard eardrums. Since already the ear is directional, the subsequent neural processing may be much simpler than in mammals, for example, where directionality is based on neural computation. Our neurophysiological experiments show that binaural comparison is based on contralateral inhibition with no apparent segregation of time and intensity processing. This simple computation generates a strongly directional lateralization that is suf cient to orient the animal. This has been shown by robot simulations, where the ear is modelled by a simple three- impedance acoustical analog. Implementation of the model in a digital signal processor and subsequent neural processing based on binaural comparison produces a robust directional response
Biophysics, neural processing and robotics of the lizard ear, a highly directional sensor
No full textThe ear of lizards shows strongly directional responses with up to 40 dB differencesinsensitivitytoipsi-andcontralateralstimulation.Thedirectionality is generated by a simple principle: strong acoustical coupling of the eardrums through the large mouth cavity. Our laser vibrometry measurements show that the lizard ear is a two-input system with approximately 0 dB contralateral transmission gain in a 2 kHz frequency band. This transmission is boosted by resonances in the large, open tympanic cavities. Probably because of these resonances, the interaural delay is approximately three times larger than the arrival-time differences at the lizard eardrums. Since already the ear is directional, the subsequent neural processing may be much simpler than in mammals, for example, where directionality is based on neural computation. Our neurophysiological experiments show that binaural comparison is based on contralateral inhibition with no apparent segregation of time and intensity processing. This simple computation generates a strongly directional lateralization that is suf cient to orient the animal. This has been shown by robot simulations, where the ear is modelled by a simple three- impedance acoustical analog. Implementation of the model in a digital signal processor and subsequent neural processing based on binaural comparison produces a robust directional response
Biophysics, neural processing and robotics of the lizard ear, a highly directional sensor
No full textThe ear of lizards shows strongly directional responses with up to 40 dB differencesinsensitivitytoipsi-andcontralateralstimulation.Thedirectionality is generated by a simple principle: strong acoustical coupling of the eardrums through the large mouth cavity. Our laser vibrometry measurements show that the lizard ear is a two-input system with approximately 0 dB contralateral transmission gain in a 2 kHz frequency band. This transmission is boosted by resonances in the large, open tympanic cavities. Probably because of these resonances, the interaural delay is approximately three times larger than the arrival-time differences at the lizard eardrums. Since already the ear is directional, the subsequent neural processing may be much simpler than in mammals, for example, where directionality is based on neural computation. Our neurophysiological experiments show that binaural comparison is based on contralateral inhibition with no apparent segregation of time and intensity processing. This simple computation generates a strongly directional lateralization that is suf cient to orient the animal. This has been shown by robot simulations, where the ear is modelled by a simple three- impedance acoustical analog. Implementation of the model in a digital signal processor and subsequent neural processing based on binaural comparison produces a robust directional response
Internettet som personaliseret og socialt medie
No full text De nye netbaserede digitale medier, der ofte går under betegnelsen social software eller Web 2.0, har ændret anvendelsen af internettet, og på få år er anvendelsen af disse medier blevet meget udbredt. Først og fremmest er e-mail og World Wide Web1 blevet taget bredt i brug og har dermed suppleret den traditionelle "push"-formidling med en "pull"-dimension, der muliggør, at interesserede kan opsøge informationerne, når og hvor de øsker det. Derudover er der de sidste par år fremkommet en række netbasrede teknologier, som muliggør social interaktion, aktiv deltagelse og egenproduktion. De mest udbredte teknologier er weblogs, wikier, sociale fælesskaber og sites til deling af digitale materialer (Freedman 2006; O'Reilly 2005; Dalsgaard 2006; Dalsgaard 2007). Disse teknologier har medført, at mediernes rolle har ændret sig.Spørgsmålet, som artiklen vil stille er, hvordan internettet kan fungere som vidensmedie. Hvad er potentialerne i internettet til at formidle og konstruere viden, og hvilke karakteristiske egenskaber har internettet som vidensmedie? Artiklen argumenterer for, at nye former for vidensdeling og vidensformidling kan opstå gennem personaliserede og sociale medier. Målet at identificere en række centrale egenskaber ved internettet i egenskab af personaliseret og socialt vidensmedie. Samtidig vil artiklen diskutere, hvordan internettet som vidensmedie muliggør, at uddannelsesinstitutioner og kulturinstitutioner kan udvide deres virke ud over deres fysiske rammer og deres hjemmesider. Artiklen afsluttes med en diskussion, der har til hensigt at pege i retning af, hvordan institutioner kan anvende digitale vidensmedier
Utilsiktet bifangst av sjøfugl i norske kystfiskerier med garn og line
No full textFangel, K., Aas, Ø., Bærum, K. M., Anker-Nilssen, T. & Christensen-Dalsgaard, S. 2015. Utilsiktet bifangst av sjøfugl i norske kystfiskerier med garn og line. - NINA Temahefte 64. 20 s.© Norsk institutt for naturforskning. Publikasjonen kan siteres fritt med kildeangivelse
Reliability Analysis of Offshore Jacket Structures with Wave Load on Deck using the Model Correction Factor Method
No full textTraditionally deterministic push-over analyses are performed for steel-jacket offshore platforms in order to calculate RSR (Reserve Strength Ratio) values as the representative reliability measure for total collapse of the structure. In this paper reliability analyses are performed for total failure/collapse of jacket type platforms with wave in deck loads using the so-called Model Correction Factor Method (MCFM). A simple representative model for the RSR measure is developed and used in the MCFM technique. A realistic example is evaluated and it is seen that it is possible to perform probabilistic reliability analysis for collapse of a jacket type platform using the model correction factor method. The total number of deterministic, complex nonlinear analysis is typically as low as 10.Traditionally deterministic push-over analyses are performed for steel-jacket offshore platforms in order to calculate RSR (Reserve Strength Ratio) values as the representative reliability measure for total collapse of the structure. In this paper reliability analyses are performed for total failure/collapse of jacket type platforms with wave in deck loads using the so-called Model Correction Factor Method (MCFM). A simple representative model for the RSR measure is developed and used in the MCFM technique. A realistic example is evaluated and it is seen that it is possible to perform probabilistic reliability analysis for collapse of a jacket type platform using the model correction factor method. The total number of deterministic, complex nonlinear analysis is typically as low as 10
Reliability-based optimization and optimal reliability level of offshore wind turbines
No full textDifferent formulations relevant for the reliability-based optimization of offshore wind turbines are presented, including different reconstruction policies in case of failure. Illustrative examples are presented and, as a part of the results, optimal reliability levels for the different failure modes are obtained as annual probabilities in the interval 2*10-4 -10-3. Reliability-based inspection models for large offshore wind turbines are presented.Different formulations relevant for the reliability-based optimization of offshore wind turbines are presented, including different reconstruction policies in case of failure. Illustrative examples are presented and, as a part of the results, optimal reliability levels for the different failure modes are obtained as annual probabilities in the interval 2*10-4 -10-3. Reliability-based inspection models for large offshore wind turbines are presented
Diarrhoeal diseases among adult population in an agricultural community Hanam province, Vietnam, with high wastewater and excreta re-use
No full textDespite the potential health risks of wastewater and excreta use as fertiliser in agriculture, it is still widespread in Vietnam. However, the importance of diarrheal risk in adults' associated with the combined exposures to both excreta and wastewater use in agriculture is largely unknown. This study was carried out to determine diarrhoeal incidence and associated risk factors among the adult population exposed to wastewater and excreta used in agriculture in Hanam province, Vietnam.; An open cohort of 867 adults, aged 16-65 years, was followed weekly for 12 months to determine the incidence of diarrhoea. A nested case-control study was used to assess the risk factors of diarrhoeal episodes. Two hundred and thirty-two pairs of cases and controls were identified and exposure information related to wastewater, human and animal excreta, personal hygiene practices, and food and water consumption was collected.; The incidence rate of reported diarrhoea was 0.28 episodes per person-years at risk. The risk factors for diarrhoeal diseases included direct contact with the Nhue River water (odds ratio [OR] = 2.4, attributable fraction [AF] 27%), local pond water (OR = 2.3, AF 14%), composting of human excreta for a duration less than 3 months (OR = 2.4, AF 51%), handling human excreta in field work (OR = 5.4, AF 7%), handling animal excreta in field work (OR = 3.3, AF 36%), lack of protective measures while working (OR = 6.9, AF 78%), never or rarely washing hands with soap (OR = 3.3, AF 51%), use of rainwater for drinking (OR = 5.4, AF 77%) and eating raw vegetables the day before (OR = 2.4, AF 12%).; Our study shows that professional exposure to wastewater and excreta during agricultural activities are significantly contributing to the risk of diarrhoea in adults. The highest attributable fractions were obtained for direct contact with Nhue River and local ponds, handling practices of human and animal excreta as fertilisers, lack of protective measures while working and poor personal hygiene practices, and unsafe food and water consumption were associated with the risk of diarrhoeal episodes in adults. Improve personal hygiene practices and use of relevant treated wastewater and excreta as the public health measures to reduce these exposures will be most effective and are urgently warranted
Experimental anal infection of rainbow trout with Flavobacterium psychrophilum : A novel challenge model
No full textFlavobacterium psychrophilum is a Gram‐negative psychrophilic bacterium causing rainbow trout fry syndrome (RTFS) in fry and bacterial coldwater disease (BCWD) in older fish. Both diseases challenge fish welfare and economy in hatcheries and in on‐growing facilities. The bacteria enter hosts through gills, skin, and the gastrointestinal tract, and transfer horizontally in contaminated water and vertically with sexual products of both male and female fish (Madetoja, Dalsgaard, & Wiklund, 2002; Madsen & Dalsgaard, 1999; Nematollahi, Decostere, Pasmans, & Haesebrouck, 2003). Protection afforded by experimental vaccination (injection or immersion) using bacterins (formalin‐killed whole cell) has been described (Hoare, Ngo, Bartie, & Adams, 2017; Madetoja et al., 2006), although no commercial vaccine is presently available for control of RTFS and BCWD. Further research on RTFS/BCWD vaccinology will benefit from an improved challenge method as current methods comprising intraperitoneal (i.p.) injection, bath, and bath exposure after treatment with stressors such as hydrogen peroxide (Henriksen, Kania, Buchmann, & Dalsgaard, 2015; Madsen & Dalsgaard, 1999) remain difficult to reproduce and rely on wounding the structural integrity of mucosal surfaces. The present study compares different infection methods and evaluates systems where the rainbow trout surface (skin, gills, and gut) is kept intact or injured. We compared six different challenge methods comprising anal intubation, i.p. injection, co‐habitation, and bath challenge exposing either nontreated intact fish, fish chemically damaged by exposure to hydrogen peroxide or fish mechanically damaged by needle insertion in the tail‐fin. Disease development was subsequently recorded for 4 weeks
Supplemental Material, DS3_TPX_10.1177_0192623318803557 - The Effect of Diet-induced Obesity on Toxicological Parameters in the Polygenic Sprague-Dawley Rat Model
No full textSupplemental Material, DS3_TPX_10.1177_0192623318803557 for The Effect of Diet-induced Obesity on Toxicological Parameters in the Polygenic Sprague-Dawley Rat Model by Jennifer M. Rojas, Florian Bolze, Inger Thorup, Jette Nowak, Charlotte M. Dalsgaard, Mikala Skydsgaard, Line O. Berthelsen, Kevin A. Keane, Henrik Søeborg, Ingrid Sjögren, Jes T. Jensen, Johannes J. Fels, Hanne K. Offenberg, Lærke W. Andersen, and Majken Dalgaard in Toxicologic Pathology</p
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