Sonar-induced temporary hearing loss in dolphins

Author Posting. © Royal Society, 2009. This is the author's version of the work. It is posted here by permission of Royal Society for personal use, not for redistribution. The definitive version was published in Biology Letters 5 (2009): 565-567, doi:10.1098/rsbl.2009.0099.There is increasing concern that human-produced ocean noise is adversely affecting marine mammals, as several recent cetacean mass strandings may have been caused by animals’ interactions with naval “mid-frequency” sonar. However, it has yet to be empirically demonstrated how sonar could induce these strandings or cause physiological effects. In controlled experimental studies, we show that mid-frequency sonar can induce temporary hearing loss in a bottlenose dolphin (Tursiops truncatus). Mild behavioural alterations were also associated with the exposures. The auditory effects were only induced by repeated exposures to intense sonar pings with total sound exposure levels of 214 dB re: 1 μPa2∙s. Data support an increasing energy model to predict temporary noise-induced hearing loss and indicate that odontocete noise exposure effects bear trends similar to terrestrial mammals. Thus, sonar can induce physiological and behavioural effects in at least one species of odontocete; however, exposures must be of prolonged, high sound exposures levels to generate these effects.Work was funded by the Office of Naval Research (Robert Gisiner and Mardi Hastings) to P.E.N. and SEAPACE (T.A.M.)

Potential for sound sensitivity in cephalopods

Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Advances in Experimental Medicine and Biology 730 (2012): 125-128, doi:10.1007/978-1-4419-7311-5_28.Hearing is a primary sense in many marine animals and we now have a reasonable understanding of what stimuli generate clear responses, the frequency range of sensitivity, expected threshold values and mecha-nisms of sound detection for several species of marine mammals and fishes (Fay 1988; Au et al. 2000). For marine invertebrates, our knowledge of hearing capabilities is relatively poor and a definition or even certainty of sound detection is not agreed upon (Webster et al. 1992) despite their magnitude of biomass and often central role in ocean ecosystems. Cephalopods (squid, cuttlefish, octopods and nautilus) are particularly interesting subjects for inver-tebrate sound detection investigations for several reasons. Ecologically, they occupy many of the same niches as sound-sensitive fish (Budelmann 1994) and may benefit from sound perception and use for the same reasons, such as to detect predators, navigate, or locate conspecifics. Squid, for example, are often the prey of loud, echolocating marine mammals (Clarke 1996), and may therefore be expected to have evolved hearing to avoid predators. Anatomically, squid have complex statocysts that are considered to serve primarily as vestibular and acceleration detectors (Nixon and Young 2003). However, statocysts may also be analogs for fish otolithic organs, detecting acoustic stimuli (Budelmann 1992). Previous studies have debated the subject of squid hearing and recently there has been a revival of research on the subject. Here, we briefly review what is known about squid sound detection, revisit hearing definitions, discuss potential squid susceptibility to anthropogenic noise and suggest potential future research direc-tions to examine squid acoustic sensitivity.2013-01-2

Predicting temporary threshold shifts in a bottlenose dolphin (Tursiops truncatus) : the effects of noise level and duration

Author Posting. © Acoustical Society of America, 2009. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 125 (2009): 1816-1826, doi:10.1121/1.3068456.Noise levels in the ocean are increasing and are expected to affect marine mammals. To examine the auditory effects of noise on odontocetes, a bottlenose dolphin (Tursiops truncatus) was exposed to octave-band noise (4–8 kHz) of varying durations (<2–30 min) and sound pressures (130–178 dB re 1 µPa). Temporary threshold shift (TTS) occurrence was quantified in an effort to (i) determine the sound exposure levels (SELs) (dB re 1 µPa2 s) that induce TTS and (ii) develop a model to predict TTS onset. Hearing thresholds were measured using auditory evoked potentials. If SEL was kept constant, significant shifts were induced by longer duration exposures but not for shorter exposures. Higher SELs were required to induce shifts in shorter duration exposures. The results did not support an equal-energy model to predict TTS onset. Rather, a logarithmic algorithm, which increased in sound energy as exposure duration decreased, was a better predictor of TTS. Recovery to baseline hearing thresholds was also logarithmic (approximately −1.8 dB/doubling of time) but indicated variability including faster recovery rates after greater shifts and longer recoveries necessary after longer duration exposures. The data reflected the complexity of TTS in mammals that should be taken into account when predicting odontocete TTS.This work was funded by the Office of Naval Research Grant No. 00014-098-1-687 to P.E.N. and the support of Bob Gisiner and Mardi Hasting is noted. Additional support came from SeaSpace to T.A.M

Composição mineral de maçãs 'Gala' produzidas em Vacaria-RS e São Joaquim-SC na safra 2012/13.

Este trabalho teve por objetivo determinar a composição mineral de frutos de macieira da cultivar Gala, produzidos em Vacaria-RS e São Joaquim-SC, na safra 2012-2013

Hearing Sensation Levels of Emitted Biosonar Clicks in an Echolocating Atlantic Bottlenose Dolphin

Emitted biosonar clicks and auditory evoked potential (AEP) responses triggered by the clicks were synchronously recorded during echolocation in an Atlantic bottlenose dolphin (Tursiops truncatus) trained to wear suction-cup EEG electrodes and to detect targets by echolocation. Three targets with target strengths of −34, −28, and −22 dB were used at distances of 2 to 6.5 m for each target. The AEP responses were sorted according to the corresponding emitted click source levels in 5-dB bins and averaged within each bin to extract biosonar click-related AEPs from noise. The AEP amplitudes were measured peak-to-peak and plotted as a function of click source levels for each target type, distance, and target-present or target-absent condition. Hearing sensation levels of the biosonar clicks were evaluated by comparing the functions of the biosonar click-related AEP amplitude-versus-click source level to a function of external (in free field) click-related AEP amplitude-versus-click sound pressure level. The results indicated that the dolphin's hearing sensation levels to her own biosonar clicks were equal to that of external clicks with sound pressure levels 16 to 36 dB lower than the biosonar click source levels, varying with target type, distance, and condition. These data may be assumed to indicate that the bottlenose dolphin possesses effective protection mechanisms to isolate the self-produced intense biosonar beam from the animal's ears during echolocation

In Vivo Time- Resolved Microtomography Reveals the Mechanics of the Blowfly Flight Motor

Dipteran flies are amongst the smallest and most agile of flying animals. Their wings are driven indirectly by large power muscles, which cause cyclical deformations of the thorax that are amplified through the intricate wing hinge. Asymmetric flight manoeuvres are controlled by 13 pairs of steering muscles acting directly on the wing articulations. Collectively the steering muscles account for <3% of total flight muscle mass, raising the question of how they can modulate the vastly greater output of the power muscles during manoeuvres. Here we present the results of a synchrotron-based study performing micrometre-resolution, time-resolved microtomography on the 145 Hz wingbeat of blowflies. These data represent the first four-dimensional visualizations of an organism's internal movements on sub-millisecond and micrometre scales. This technique allows us to visualize and measure the three-dimensional movements of five of the largest steering muscles, and to place these in the context of the deforming thoracic mechanism that the muscles actuate. Our visualizations show that the steering muscles operate through a diverse range of nonlinear mechanisms, revealing several unexpected features that could not have been identified using any other technique. The tendons of some steering muscles buckle on every wingbeat to accommodate high amplitude movements of the wing hinge. Other steering muscles absorb kinetic energy from an oscillating control linkage, which rotates at low wingbeat amplitude but translates at high wingbeat amplitude. Kinetic energy is distributed differently in these two modes of oscillation, which may play a role in asymmetric power management during flight control. Structural flexibility is known to be important to the aerodynamic efficiency of insect wings, and to the function of their indirect power muscles. We show that it is integral also to the operation of the steering muscles, and so to the functional flexibility of the insect flight motor

Passenger car data – a new source of real-time weather information for nowcasting, forecasting, and road safety

Presentación realizada en la 3rd European Nowcasting Conference, celebrada en la sede central de AEMET en Madrid del 24 al 26 de abril de 2019

Pneumococcal phosphoglycerate kinase interacts with plasminogen and its tissue activator

18 pags, 8 figs, 1 tabStreptococcus pneumoniae is not only a commensal of the nasopharyngeal epithelium, but may also cause life-threatening diseases. Immune- electron microscopy studies revealed that the bacterial glycolytic enzyme, phosphoglycerate kinase (PGK), is localised on the pneumococcal surface of both capsulated and non-capsulated strains and colocalises with plasminogen. Since pneumococci may concentrate host plasminogen (PLG) together with its activators on the bacterial cell surface to facilitate the formation of plasmin, the involvement of PGK in this process was studied. Specific binding of human or murine PLG to strain-independent PGK was documented, and surface plasmon resonance analyses indicated a high affinity interaction with the kringle domains 1-4 of PLG. Crystal structure determination of pneumococcal PGK together with peptide array analysis revealed localisation of PLG-binding site in the N-terminal region and provided structural motifs for the interaction with PLG. Based on structural analysis data, a potential interaction of PGK with tissue plasminogen activator (tPA) was proposed and experimentally confirmed by binding studies, plasmin activity assays and thrombus degradation analyses. © Schattauer 2014.The research leading to these results has received funding from the European Community’s Seventh Framework Program under Grant Agreement no. HEALTH-F3–2009–223111. This work was also supported by grants from the Spanish Ministry of Economy and Competitiveness (BFU2011–25326) and Comunidad Autónoma de Madrid (CAM) S2010-BMD-2457 (BIPEDD2). J.K. is funded by a grant from Ministerio de Economía y Competitividad (BFU2011–24595). A.M. also acknowledges CAM for financial support to the Fundación Severo Ochoa through the AMAROUTO progra

Density-functional study of hydrogen chemisorption on vicinal Si(001) surfaces

Relaxed atomic geometries and chemisorption energies have been calculated for the dissociative adsorption of molecular hydrogen on vicinal Si(001) surfaces. We employ density-functional theory, together with a pseudopotential for Si, and apply the generalized gradient approximation by Perdew and Wang to the exchange-correlation functional. We find the double-atomic-height rebonded D_B step, which is known to be stable on the clean surface, to remain stable on partially hydrogen-covered surfaces. The H atoms preferentially bind to the Si atoms at the rebonded step edge, with a chemisorption energy difference with respect to the terrace sites of >sim 0.1 eV. A surface with rebonded single atomic height S_A and S_B steps gives very similar results. The interaction between H-Si-Si-H mono-hydride units is shown to be unimportant for the calculation of the step-edge hydrogen-occupation. Our results confirm the interpretation and results of the recent H_2 adsorption experiments on vicinal Si surfaces by Raschke and Hoefer described in the preceding paper.Comment: 13 pages, 8 figures, submitted to Phys. Rev. B. Other related publications can be found at http://www.rz-berlin.mpg.de/th/paper.htm

Overtone Mobility Spectrometry: Part 2. Theoretical Considerations of Resolving Power

The transport of ions through multiple drift regions is modeled to develop an equation that is useful for an understanding of the resolving power of an overtone mobility spectrometry (OMS) technique. It is found that resolving power is influenced by a number of experimental variables, including those that define ion mobility spectrometry (IMS) resolving power: drift field (E), drift region length (L), and buffer gas temperature (T). However, unlike IMS, the resolving power of OMS is also influenced by the number of drift regions (n), harmonic frequency value (m), and the phase number (⌽) of the applied drift field. The OMS resolving power dependence upon the new OMS variables (n, m, and ⌽) scales differently than the square root dependence of the E, L, and T variables in IMS. The results provide insight about optimal instrumental design and operation. (J Am Soc Mass Spectrom 2009, 20, 738 -750) © 2009 American Society for Mass Spectrometry W hen a pulse of ions is injected into a buffer gas, different species separate under the influence of an electric field because of differences in their mobilities through the buffer gas Of note is the dependence of resolving power on the square root of the various parameters. This relationship imposes limits on the ultimate instrument performance. For example, doubling L does not double the resolving power; rather, a 2-fold increase in L (holding T and E constant) results in only ϳ40% increase in resolving power. In the present paper, we report modeling studies of ion transport through multiple drift regions to which the drift fields are applied at varying frequencies, the experimental setup used in overtone mobility spectrometry (OMS). The understanding that is gained from modeling allows us to develop a simple equation that can be used to estimate the OMS resolving power (R OMS ). The equation describing the OMS resolving power accounts for a number of geometrical OMS device configurations as well as those parameters used to define R IMS . However, these studies indicate that variation of the parameters which define R IMS (E, L, and T) have only a limited impact on the R OMS . Instead, the factors having the greatest influence on R OMS appear to be the number of phases for the system (i.e., the number of unique drift field application settings as well as the number of drift regions in a complete ion transmission/ elimination cycle, see below for complete description), the overall number of ion drift regions, and the drift field setting frequency (overtone number). A surprising result is the unit proportionality relationship between R OMS and the number of drift regions (in effect L) as well as the frequency suggesting the ability to garner much improved instrument performance (with respect to resolution) for proportionate changes when compared with IMS techniques. It is important to note that the comparisons to R IMS (with respect to L) described here are based on the use of a constant drift field. Equation 1 can be rewritten such that the product of L and E is denoted as the drift voltage (V). Extensive work has shown that increased resolving power can be obtained by optimizing V and Address reprint requests to Dr