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37 results on '"Dolev, Amit"'

1. 3D printed acoustically programmable soft microactuators

Author

Kaynak, Murat, Dolev, Amit, and Sakar, Mahmut Selman

Subjects
Physics - Applied Physics, Physics - Fluid Dynamics
Abstract

The concept of creating all-mechanical soft microrobotic systems has great potential to address outstanding challenges in biomedical applications, and introduce more sustainable and multifunctional products. To this end, magnetic fields and light have been extensively studied as potential energy sources. On the other hand, coupling the response of materials to pressure waves has been overlooked despite the abundant use of acoustics in nature and engineering solutions. Here, we show that programmed commands can be contained on 3D nanoprinted polymer systems with the introduction of selectively excited air bubbles and rationally designed compliant mechanisms. A repertoire of micromechanical systems is engineered using experimentally validated computational models that consider the effects of primary and secondary pressure fields on entrapped air bubbles and the surrounding fluid. Coupling the dynamics of bubble oscillators reveals rich acoustofluidic interactions that can be programmed in space and time. We prescribe kinematics by harnessing the forces generated through these interactions to deform structural elements, which can be remotely reconfigured on-demand with the incorporation of mechanical switches. These basic micromechanical systems will serve as the building blocks for the development of a novel class of untethered soft microrobots powered and controlled by acoustic signals., Comment: 6 Figures, 11 Supplementary Figures, 2 Supplementary Tables

Published
2022

2. Dynamics of entrapped microbubbles with multiple openings

Author

Dolev, Amit, Kaynak, Murat, and Sakar, Mahmut Selman

Subjects
Physics - Fluid Dynamics, Physics - Applied Physics
Abstract

Microbubbles excited by acoustic fields inside water oscillate, and generate acoustic radiation forces and drag-induced acoustic streaming. These forces can be harnessed in various biomedical applications such as targeted drug delivery and on-chip biomanipulation. The conventional approach for using microbubbles as actuators is to trap them inside microfabricated cavities. Anisotropic forces are applied by constraining the interfaces where the air interacts with water. The existing analytical models derived for spherical bubbles are incapable of predicting the dynamics of bubbles in such configurations. Here, a new model for bubbles entrapped inside arbitrarily shaped cavities with multiple circular openings is developed. The semi-analytical model captures a more realistic geometry through a solution to an optimization problem. We challenge the assumption that bubbles should be excited at their first resonance frequency to optimize their performance. The natural frequencies and the correlated normal vibration modes are calculated, which are subsequently used to compute the acoustic streaming patterns and the associated thrust by a finite element simulation. An experimental platform was built to measure the deflection of beams loaded by microfabricated bubble actuators, and visualize the generated streaming patterns. The results highlight the contribution of the computational model as a design tool for engineering applications., Comment: 34 pages, 10 figures, 2 tables, 5 supplementary figures

Published
2021
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3. Balancing rotating structures using slow-speed data via optimized parametric excitation and nonlinear feedback

Author

Dolev, Amit, Tresser, Shachar, and Bucher, Izhak

Subjects
Physics - Applied Physics
Abstract

The paper presents an improved mass balancing procedure for fast rotating machinery, while it is being rotated at speeds considerably slower than the "critical speeds", where dangerously high vibration amplitudes may arise. By utilizing tuned dual frequency parametric excitation along with optimized nonlinear feedback terms, the slow imbalance forces are projected onto a chosen mode of vibration. This allows to identify the imbalance projection on that specific mode, and to cancel these forces by adding or reducing mass. The scheme benefits from two kinds of parametric excitation yielding combination and principal parametric resonances. The former is used to project the imbalance forces onto a selected vibration mode, and the latter significantly amplifies the response. By tuning the parametric excitation and the nonlinear terms in an optimal manner, a pseudo-linear behavior is formed. This behavior enables to increase both amplification and sensitivity to the imbalance forces without having to compromise between the two., Comment: 14 pages, 11 Figures. Published in Proceedings of ISMA 2018 Including USD 2018 https://www.isma-isaac.be/publications/

Published
2018

4. Analytical, numerical and experimental investigation of a tunable, nonlinear multi-degree-of-freedom parametrically excited amplifier

Author

Dolev, Amit and Bucher, Izhak

Subjects
Physics - Applied Physics
Abstract

A tunable, multi-degree-of-freedom, parametrically excited amplifier is introduced as an apparatus capable of shifting slow, weak signals to higher frequencies, by exploiting the amplifier natural resonances via controlled parametric excitation and nonlinear feedback. This device can find use as a signal amplifier and as a spectrum control device. A tuned dual-frequency signal is created to parametrically excite (pump) the system and produce the desired energy shift. The pump signal is applied by a controlled electromechanical actuator, and is modified in-situ according to the slow frequency signal and the desired response. A three DOF model is introduced, and the governing nonlinear EOM are derived and solved analytically via asymptotic methods and verified with numerical simulations. A parametric design of an experimental rig was carried out, and the importance of experimental calibration and system identification is emphasized. Some preliminary experimental results are provided with favorable agreement with the theory., Comment: 15 pages, 8 figures. Published in the proceedings of ISMA 2016 including USD 2016 http://past.isma-isaac.be/isma2016/proceedings/abstracts/

Published
2018

5. Optimizing the dynamical behavior of a dual frequency parametric amplifier with quadratic and cubic nonlinearities

Author

Dolev, Amit and Bucher, Izhak

Subjects
Physics - Applied Physics
Abstract

The paper describes a novel parametric excitation scheme that acts as a tunable amplifier by controlling two pumping signals and two nonlinear feedback terms. By modulating the stiffness of a mechanical oscillator with a digital signal processor, low frequency inputs are projected onto a higher resonance frequency, thus exploiting the natural selective filtering of such structures. Described is an optimized dual-term nonlinear stiffness resonator that enhances the input signal level and the sensitivity to changes in both amplitude and phase, while limiting the obtained response to desired levels. This amplifier is geared to cases when the frequency of the input is known or measurable, like in rotating structures, while the amplitude and phase are too weak to be detected without amplification. It is shown that by tuning the cubic and quadratic feedback terms, the amplifier benefits from a nearly linear response behavior, while exploiting the benefits of nonlinear and pumping signal enhancements., Comment: 33 pages,14 Figures, Submitted to Nonlinear Dynamics - Springer (NODY)

Published
2018
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6. Dual frequency parametric excitation of a nonlinear multi degree of freedom amplifier with a digitally modified topology

Author

Dolev, Amit and Bucher, Izhak

Subjects
Physics - Applied Physics
Abstract

Mechanical or electromechanical amplifiers can exploit the high-Q and low noise features of mechanical resonance, in particular when parametric excitation is employed. Multi-frequency parametric excitation introduces tunability and is able to project weak input signals on a selected resonance. The present paper addresses multi degree of freedom mechanical amplifiers or resonators whose analysis and features require treatment of the spatial as well as temporal behavior. In some cases, virtual electronic coupling can alter the given topology of the resonator to better amplify specific inputs. An analytical development is followed by a numerical and experimental sensitivity and performance verifications, illustrating the advantages and disadvantages of such topologies.

Published
2017
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7. Dynamic balancing of super-critical rotating structures using slow-speed data via parametric excitation

Author

Tresser, Shachar, Dolev, Amit, and Bucher, Izhak

Subjects
Physics - Applied Physics
Abstract

High-speed machinery is often designed to pass several $"$critical$"$ speeds, where vibration levels can be very high. To reduce vibrations, rotors usually undergo a mass balancing process, where the machine is rotated at its full speed range, during which the dynamic response near critical speeds can be measured. High sensitivity, which is required for a successful balancing process, is achieved near the critical speeds, where a single deflection mode shape becomes dominant, and is excited by the projection of the imbalance on it. The requirement to rotate the machine at high speeds is an obstacle in many cases, where it is impossible to perform measurements at high speeds, due to harsh conditions such as high temperatures and inaccessibility (e.g., jet engines). $\\$ This paper proposes a novel balancing method of flexible rotors, which does not require the machine to be rotated at high speeds. With this method, the rotor is spun at low speeds, while subjecting it to a set of externally controlled forces. The external forces comprise a set of tuned, response dependent, parametric excitations, and nonlinear stiffness terms. The parametric excitation can isolate any desired mode, while keeping the response directly linked to the imbalance. A software controlled nonlinear stiffness term limits the response, hence preventing the rotor to become unstable. These forces warrant sufficient sensitivity required to detect the projection of the imbalance on any desired mode without rotating the machine at high speeds. Analytical, numerical and experimental results are shown to validate and demonstrate the method., Comment: 35 pages, 20 figures, submitted to Journal of Sound and Vibrations

Published
2017
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10. Investigating patient-specific mechanisms of change in SET vs. EFT for depression: study protocol for a mechanistic randomized controlled trial

Author

Sigal Zilcha-Mano, Ben Shahar, Hadar Fisher, Tohar Dolev-Amit, Leslie S. Greenberg, and Jacques P. Barber

Subjects
Personalized treatment, Supportive-expressive treatment, Emotion-focused treatment, Mechanisms of change, Insight, Emotional processing, Psychiatry, RC435-571
Abstract

Abstract Background Major depressive disorder (MDD) is the leading cause of disability worldwide and one of the most heterogeneous mental health disorders. Although there are effective treatments for MDD, about 50% of patients do not respond to treatment. One of the greatest challenges in improving current treatments is identifying the mechanisms responsible for therapeutic change in MDD. The proposed study aims to identify patient-specific mechanisms of change in two treatments for MDD by investigating whether subpopulations of patients differ in the mechanisms of change that operate when receiving a given treatment. Based on theories of targeting weakness and building on strength, we will examine whether the mechanism of change operating when a treatment is provided depends on whether the treatment targets the patient’s strength or weakness. Method To test our hypothesis that two treatments, supportive-expressive treatment (SET) and emotion-focused treatment (EFT), differ in their mechanisms of change and to explore whether focusing on the patient’s strength or weakness will result in better treatment outcome, we conduct a mechanistic randomized controlled trial. One hundred and twenty-four individuals diagnosed with MDD are randomized to 16 sessions of either SET or EFT. The two treatments are theorized to differ in their main mechanism of change: SET places emphasis on insight as its main mechanism of change, and EFT places emphasis on emotional processing. Both can serve as strength- or weakness-focused treatments, based on the patient’s baseline levels of insight and emotional processing. The primary outcome is the Hamilton Rating Scale for Depression. Additional measures include self-report measures and clinical interviews, hormonal, motion, acoustic, physiological, and neuroimaging assessments, performance on cognitive tasks, and narrative material (collected from the sessions and interviews). Discussion The RCT will expand our understanding of mechanisms of change in psychotherapy, from one-size-fits-all to patient-specific mechanisms of change. By informing therapists about which of the two approaches is most effective with patients based on their baseline characteristics, the RCT will contribute to progress toward personalized treatment. Trial registration clinicaltrials.gov Identifier: NCT04576182 submitted on October 1st 2020. Funding: The Israel Science Foundation. Trial status: Recruitment is ongoing.

Published
2021
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20. Relationships of biomedical beliefs about depression to treatment-related expectancies in a treatment-seeking sample

Author

Matthew S Lebowitz, Sigal Zilcha-Mano, and Tohar Dolev-Amit

Subjects
Depressive Disorder, Depression, Therapeutic Alliance, media_common.quotation_subject, MEDLINE, Sample (statistics), PsycINFO, Pessimism, Article, Psychotherapy, Psychiatry and Mental health, Clinical Psychology, Seekers, Alliance, Humans, Psychology, Attribution, Depression (differential diagnoses), Clinical psychology, media_common
Abstract

Like other mental disorders, major depression is increasingly explained as a biomedical illness. We examined, in a treatment-seeking sample, whether attributing one's depression to biomedical causes would be associated with pessimistic psychotherapy treatment expectancies. Individuals seeking psychotherapy for depression rated their endorsement of biomedical explanations for their symptoms, expectations regarding treatment outcome, and expectations about forming a working alliance with a therapist. We found that treatment seekers' endorsement of biomedical explanations for their symptoms was associated with pessimism about treatment being successful. This pessimism was, in turn, associated with holding more negative expectancies about one's ability to form a strong therapeutic alliance with a therapist. Given the ascendancy of biomedical explanations for depression and the influence of patient expectancies on clinical outcomes, strategies for disassociating biomedical attributions from pessimistic expectancies may be needed. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Published
2021

22. Repairing alliance ruptures using supportive techniques in telepsychotherapy during the COVID-19 pandemic

Author

Liat Leibovich, Tohar Dolev-Amit, and Sigal Zilcha-Mano

Subjects
050103 clinical psychology, 2019-20 coronavirus outbreak, medicine.medical_specialty, Forcing (recursion theory), Coronavirus disease 2019 (COVID-19), Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), 05 social sciences, 050106 general psychology & cognitive sciences, Psychiatry and Mental health, Clinical Psychology, Alliance, Political science, Pandemic, medicine, 0501 psychology and cognitive sciences, Intensive care medicine, Applied Psychology
Abstract

The COVID-19 pandemic shifted many traditional face-to-face treatments to telepsychotherapy, forcing many therapists worldwide to adapt effective techniques developed in face-to-face treatment to t...

Published
2020
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24. Global COVID-19 lockdown highlights humans as both threats and custodians of the environment

Author

Bates, Amanda E., Primack, Richard B., Biggar, Brandy S., Bird, Thomas J., Clinton, Mary E., Command, Rylan J., Richards, Cerren, Shellard, Marc, Geraldi, Nathan R., Vergara, Valeria, Acevedo-Charry, Orlando, Colón-Piñeiro, Zuania, Ocampo, David, Ocampo-Peñuela, Natalia, Sánchez-Clavijo, Lina M., Adamescu, Cristian M., Cheval, Sorin, Racoviceanu, Tudor, Adams, Matthew D., Kalisa, Egide, Kuuire, Vincent Z., Aditya, Vikram, Anderwald, Pia, Wiesmann, Samuel, Wipf, Sonja, Badihi, Gal, Henderson, Matthew G., Loetscher, Hanspeter, Baerenfaller, Katja, Benedetti-Cecchi, Lisandro, Bulleri, Fabio, Bertocci, Lacopo, Maggi, Elena, Rindi, Luca, Ravaglioli, Chiara, Boerder, Kristina, Bonnel, Julien, Mathias, Delphine, Archambault, Philippe, Chauvaud, Laurent, Braun, Camrin D., Thorrold, Simon R., Brownscombe, Jacob W., Midwood, Jonathan D., Boston, Christine M., Brooks, Jill L., Cooke, Steven J., China, Victor, Roll, Uri, Belmaker, Jonathan, Zvuloni, Assaf, Coll, Marta, Ortega, Miquel, Connors, Brendan, Lacko, Lisa, Jayathilake, Dinusha R.M., Costello, Mark J., Crimmins, Theresa M., Barnett, LoriAnne, Denny, Ellen G., Gerst, Katharine L., Marsh, R.L., Posthumus, Erin E., Rodriguez, Reilly, Rosemartin, Alyssa, Schaffer, Sara N., Switzer, Jeff R., Wong, Kevin, Cunningham, Susan J., Sumasgutner, Petra, Amar, Arjun, Thomson, Robert L., Stofberg, Miqkayla, Hofmeyr, Sally, Suri, Jessleena, Stuart-Smith, Rick D., Day, Paul B., Edgar, Graham J., Cooper, Antonia T., Cabrera De Leo, Fabio, Garner, Grant, Des Brisay, Paulson G., Schrimpf, Michael B., Koper, Nicola, Diamond, Michael S., Dwyer, Ross G., Baker, Cameron J, Franklin, Craig E., Efrat, Ron, Berger-Tal, Oded, Hatzofe, Ohad, Eguíluz, Víctor M., Rodríguez, Jorge P., Fernández-Gracia, Juan, Elustondo, David, Calatayud, Vicent, English, Philina A., Archer, Stephanie K., Dudas, Sarah E., Haggarty, Dana R., Gallagher, Austin J., Shea, Brandan D., Shipley, Oliver N., Gilby, Ben L., Ballantyne, Jasmine, Olds, Andrew D., Henderson, Christopher J., Schlacher, Thomas A., Halliday, William D., Brown, Nicholas A.W., Woods, Mackenzie B., Balshine, Sigal, Juanes, Francis, Rider, Mitchell J., Albano, Patricia S., Hammerschlag, Neil, Hays, Graeme C., Esteban, Nicole, Pan, Yuhang, He, Guojun, Tanaka, Takanao, Hensel, Marc J.S., Orth, Robert J., Patrick, Christopher J., Hentati-Sundberg, Jonas, Olsson, Olof, Hessing-Lewis, Margot L., Higgs, Nicholas D., McMahon, Clive R., Harcourt, Rob, Guinet, Christophe, Hirsch, Sarah E., Perrault, Justin R., Hoover, Shelby R., Reilly, Jennifer D., Hobaiter, Catherine, Gruber, Thibaud, Huveneers, Charlie, Udyawer, Vinay, Clarke, Thomas M., Kroesen, Laura P., Hik, David S., Cherry, Seth G., Del Bel Belluz, Justin A., Jackson, Jennifer M., Lai, Shengjie, Lamb, Clayton T., LeClair, Gregory D., Parmelee, Jeffrey R., Chatfield, Matthew W.H., Frederick, Cheryl A., Lee, Sangdon, Park, Hyomin, Choi, Jaein, LeTourneux, Frédéric, Grandmont, Thierry, Dulude de-Broin, Frédéric, Bêty, Joël, Gauthier, Gilles, Legagneux, Pierre, Lewis, Jesse S., Haight, Jeffrey, Liu, Zhu, Lyon, Jarod P., Hale, Robin, D'Silva, Dallas, MacGregor-Fors, Ian, Arbelaez-Cortes, Enrique, Estela, Felipe A., Sánchez-Sarria, Camilo E., García-Arroyo, Michelle, Aguirre-Samboní, Giann K., Franco Morales, Juan C., Malamud, Shahar, Gavriel, Tal, Buba, Yehezkel, Salingré, Shira, Lazarus, Mai, Yahel, Ruthy, Ben Ari, Yigael, Miller, Eyal, Sade, Rotem, Lavian, Guy, Birman, Ziv, Gury, Manor, Baz, Harel, Baskin, Ilia, Penn, Alon, Dolev, Amit, Licht, Ogen, Karkom, Tabi, Davidzon, Sharon, Berkovitch, Avi, Yaakov, Ofer, Manenti, Raoul, Mori, Emiliano, Ficetola, Gentile Francesco, Lunghi, Enrico, March, David, Godley, Brendan J., Martin, Cecilia, Mihaly, Steven F., Barclay, David R., Thomson, Dugald J.M., Dewey, Richard, Bedard, Jeannette, Miller, Aroha, Dearden, Amber, Chapman, Jennifer, Dares, Lauren, Borden, Laura, Gibbs, Donna, Schultz, Jessica, Sergeenko, Nikita, Francis, Fiona, Weltman, Amanda, Moity, Nicolas, Ramírez-González, Jorge, Mucientes, Gonzalo, Alonso-Fernández, Alexandre, Namir, Itai, Bar-Massada, Avi, Chen, Ron, Yedvab, Shmulik, Okey, Thomas A., Oppel, Steffen, Arkumarev, Volen, Bakari, Samuel, Dobrev, Vladimir, Saravia-Mullin, Victoria, Bounas, Anastasios, Kret, Elzbieta, Mengistu, Solomon, Pourchier, Cloé, Ruffo, Alazar, Tesfaye, Million, Wondafrash, Mengistu, Nikolov, Stoyan C., Palmer, Charles, Sileci, Lorenzo, Rex, Patrick T., Lowe, Christopher G., Peters, Francesc, Pine, Matthew K., Radford, Craig A, Wilson, Louise, McWhinnie, Lauren, Scuderi, Alessia, Jeffs, Andrew G., Prudic, Kathleen L., Larrivée, Maxim, McFarland, Kent P., Solis, Rodrigo, Hutchinson, Rebecca A., Queiroz, Nuno, Furtado, Miguel A., Sims, David W., Southall, Emily, Quesada-Rodriguez, Claudio A., Diaz-Orozco, Jessica P., Rodgers, Ku'ulei S., Severino, Sarah J.L., Graham, Andrew, Stefanak, Matthew P., Madin, Elizabeth M.P., Ryan, Peter G., Maclean, Kyle, Weideman, Eleanor A., Sekercioğlu, Cağan H., Kittelberger, Kyle D., Kusak, Josip, Seminoff, Jeffrey A., Hanna, Megan E., Shimada, Takahiro, Meekan, Mark G., Smith, Martin, Mokhatla, Mohlamatsane M., Soh, Malcolm C.K., Pang, Roanna Y.T., Ng, Breyl X.K., Lee, Benjamin P.Y.-H., Loo, Adrian H.B., Er, Kenneth B.H., Souza, Gabriel B.G., Stallings, Christopher D., Curtis, Joseph S., Faletti, Meaghan E., Peake, Jonathan A., Schram, Michael J., Wall, Kara R., Terry, Carina, Rothendler, Matt, Zipf, Lucy, Ulloa, Juan Sebastián, Hernández-Palma, Angélica, Gómez-Valencia, Bibiana, Cruz-Rodríguez, Cristian, Herrera-Varón, Yenifer, Roa, Margarita, Rodríguez-Buriticá, Susana, Ochoa-Quintero, Jose Manuel, Vardi, Reut, Vázquez, Víctor, Requena-Mesa, Christian, Warrington, Miyako H., Taylor, Michelle E., Woodall, Lucy C., Stefanoudis, Paris V., Zhang, Xiangliang, Yang, Qiang, Zukerman, Yuval, Sigal, Zehava, Ayali, Amir, Clua, Eric, Carzon, Pamela, Seguine, Clementine, Corradini, Andrea, Pedrotti, Luca, Foley, Catherine M., Gagnon, Catherine Alexandra, Panipakoochoo, Elijah, Milanes, Celene B., Botero, Camilo M., Velázquez, Yunior R., Milchakova, Nataliya A., Morley, Simon A., Martin, Stephanie M., Nanni, Veronica, Otero, Tania, Wakeling, Julia, Abarro, Sarah, Piou, Cyril, et al., Bates, Amanda E., Primack, Richard B., Biggar, Brandy S., Bird, Thomas J., Clinton, Mary E., Command, Rylan J., Richards, Cerren, Shellard, Marc, Geraldi, Nathan R., Vergara, Valeria, Acevedo-Charry, Orlando, Colón-Piñeiro, Zuania, Ocampo, David, Ocampo-Peñuela, Natalia, Sánchez-Clavijo, Lina M., Adamescu, Cristian M., Cheval, Sorin, Racoviceanu, Tudor, Adams, Matthew D., Kalisa, Egide, Kuuire, Vincent Z., Aditya, Vikram, Anderwald, Pia, Wiesmann, Samuel, Wipf, Sonja, Badihi, Gal, Henderson, Matthew G., Loetscher, Hanspeter, Baerenfaller, Katja, Benedetti-Cecchi, Lisandro, Bulleri, Fabio, Bertocci, Lacopo, Maggi, Elena, Rindi, Luca, Ravaglioli, Chiara, Boerder, Kristina, Bonnel, Julien, Mathias, Delphine, Archambault, Philippe, Chauvaud, Laurent, Braun, Camrin D., Thorrold, Simon R., Brownscombe, Jacob W., Midwood, Jonathan D., Boston, Christine M., Brooks, Jill L., Cooke, Steven J., China, Victor, Roll, Uri, Belmaker, Jonathan, Zvuloni, Assaf, Coll, Marta, Ortega, Miquel, Connors, Brendan, Lacko, Lisa, Jayathilake, Dinusha R.M., Costello, Mark J., Crimmins, Theresa M., Barnett, LoriAnne, Denny, Ellen G., Gerst, Katharine L., Marsh, R.L., Posthumus, Erin E., Rodriguez, Reilly, Rosemartin, Alyssa, Schaffer, Sara N., Switzer, Jeff R., Wong, Kevin, Cunningham, Susan J., Sumasgutner, Petra, Amar, Arjun, Thomson, Robert L., Stofberg, Miqkayla, Hofmeyr, Sally, Suri, Jessleena, Stuart-Smith, Rick D., Day, Paul B., Edgar, Graham J., Cooper, Antonia T., Cabrera De Leo, Fabio, Garner, Grant, Des Brisay, Paulson G., Schrimpf, Michael B., Koper, Nicola, Diamond, Michael S., Dwyer, Ross G., Baker, Cameron J, Franklin, Craig E., Efrat, Ron, Berger-Tal, Oded, Hatzofe, Ohad, Eguíluz, Víctor M., Rodríguez, Jorge P., Fernández-Gracia, Juan, Elustondo, David, Calatayud, Vicent, English, Philina A., Archer, Stephanie K., Dudas, Sarah E., Haggarty, Dana R., Gallagher, Austin J., Shea, Brandan D., Shipley, Oliver N., Gilby, Ben L., Ballantyne, Jasmine, Olds, Andrew D., Henderson, Christopher J., Schlacher, Thomas A., Halliday, William D., Brown, Nicholas A.W., Woods, Mackenzie B., Balshine, Sigal, Juanes, Francis, Rider, Mitchell J., Albano, Patricia S., Hammerschlag, Neil, Hays, Graeme C., Esteban, Nicole, Pan, Yuhang, He, Guojun, Tanaka, Takanao, Hensel, Marc J.S., Orth, Robert J., Patrick, Christopher J., Hentati-Sundberg, Jonas, Olsson, Olof, Hessing-Lewis, Margot L., Higgs, Nicholas D., McMahon, Clive R., Harcourt, Rob, Guinet, Christophe, Hirsch, Sarah E., Perrault, Justin R., Hoover, Shelby R., Reilly, Jennifer D., Hobaiter, Catherine, Gruber, Thibaud, Huveneers, Charlie, Udyawer, Vinay, Clarke, Thomas M., Kroesen, Laura P., Hik, David S., Cherry, Seth G., Del Bel Belluz, Justin A., Jackson, Jennifer M., Lai, Shengjie, Lamb, Clayton T., LeClair, Gregory D., Parmelee, Jeffrey R., Chatfield, Matthew W.H., Frederick, Cheryl A., Lee, Sangdon, Park, Hyomin, Choi, Jaein, LeTourneux, Frédéric, Grandmont, Thierry, Dulude de-Broin, Frédéric, Bêty, Joël, Gauthier, Gilles, Legagneux, Pierre, Lewis, Jesse S., Haight, Jeffrey, Liu, Zhu, Lyon, Jarod P., Hale, Robin, D'Silva, Dallas, MacGregor-Fors, Ian, Arbelaez-Cortes, Enrique, Estela, Felipe A., Sánchez-Sarria, Camilo E., García-Arroyo, Michelle, Aguirre-Samboní, Giann K., Franco Morales, Juan C., Malamud, Shahar, Gavriel, Tal, Buba, Yehezkel, Salingré, Shira, Lazarus, Mai, Yahel, Ruthy, Ben Ari, Yigael, Miller, Eyal, Sade, Rotem, Lavian, Guy, Birman, Ziv, Gury, Manor, Baz, Harel, Baskin, Ilia, Penn, Alon, Dolev, Amit, Licht, Ogen, Karkom, Tabi, Davidzon, Sharon, Berkovitch, Avi, Yaakov, Ofer, Manenti, Raoul, Mori, Emiliano, Ficetola, Gentile Francesco, Lunghi, Enrico, March, David, Godley, Brendan J., Martin, Cecilia, Mihaly, Steven F., Barclay, David R., Thomson, Dugald J.M., Dewey, Richard, Bedard, Jeannette, Miller, Aroha, Dearden, Amber, Chapman, Jennifer, Dares, Lauren, Borden, Laura, Gibbs, Donna, Schultz, Jessica, Sergeenko, Nikita, Francis, Fiona, Weltman, Amanda, Moity, Nicolas, Ramírez-González, Jorge, Mucientes, Gonzalo, Alonso-Fernández, Alexandre, Namir, Itai, Bar-Massada, Avi, Chen, Ron, Yedvab, Shmulik, Okey, Thomas A., Oppel, Steffen, Arkumarev, Volen, Bakari, Samuel, Dobrev, Vladimir, Saravia-Mullin, Victoria, Bounas, Anastasios, Kret, Elzbieta, Mengistu, Solomon, Pourchier, Cloé, Ruffo, Alazar, Tesfaye, Million, Wondafrash, Mengistu, Nikolov, Stoyan C., Palmer, Charles, Sileci, Lorenzo, Rex, Patrick T., Lowe, Christopher G., Peters, Francesc, Pine, Matthew K., Radford, Craig A, Wilson, Louise, McWhinnie, Lauren, Scuderi, Alessia, Jeffs, Andrew G., Prudic, Kathleen L., Larrivée, Maxim, McFarland, Kent P., Solis, Rodrigo, Hutchinson, Rebecca A., Queiroz, Nuno, Furtado, Miguel A., Sims, David W., Southall, Emily, Quesada-Rodriguez, Claudio A., Diaz-Orozco, Jessica P., Rodgers, Ku'ulei S., Severino, Sarah J.L., Graham, Andrew, Stefanak, Matthew P., Madin, Elizabeth M.P., Ryan, Peter G., Maclean, Kyle, Weideman, Eleanor A., Sekercioğlu, Cağan H., Kittelberger, Kyle D., Kusak, Josip, Seminoff, Jeffrey A., Hanna, Megan E., Shimada, Takahiro, Meekan, Mark G., Smith, Martin, Mokhatla, Mohlamatsane M., Soh, Malcolm C.K., Pang, Roanna Y.T., Ng, Breyl X.K., Lee, Benjamin P.Y.-H., Loo, Adrian H.B., Er, Kenneth B.H., Souza, Gabriel B.G., Stallings, Christopher D., Curtis, Joseph S., Faletti, Meaghan E., Peake, Jonathan A., Schram, Michael J., Wall, Kara R., Terry, Carina, Rothendler, Matt, Zipf, Lucy, Ulloa, Juan Sebastián, Hernández-Palma, Angélica, Gómez-Valencia, Bibiana, Cruz-Rodríguez, Cristian, Herrera-Varón, Yenifer, Roa, Margarita, Rodríguez-Buriticá, Susana, Ochoa-Quintero, Jose Manuel, Vardi, Reut, Vázquez, Víctor, Requena-Mesa, Christian, Warrington, Miyako H., Taylor, Michelle E., Woodall, Lucy C., Stefanoudis, Paris V., Zhang, Xiangliang, Yang, Qiang, Zukerman, Yuval, Sigal, Zehava, Ayali, Amir, Clua, Eric, Carzon, Pamela, Seguine, Clementine, Corradini, Andrea, Pedrotti, Luca, Foley, Catherine M., Gagnon, Catherine Alexandra, Panipakoochoo, Elijah, Milanes, Celene B., Botero, Camilo M., Velázquez, Yunior R., Milchakova, Nataliya A., Morley, Simon A., Martin, Stephanie M., Nanni, Veronica, Otero, Tania, Wakeling, Julia, Abarro, Sarah, Piou, Cyril, and et al.

Abstract

The global lockdown to mitigate COVID-19 pandemic health risks has altered human interactions with nature. Here, we report immediate impacts of changes in human activities on wildlife and environmental threats during the early lockdown months of 2020, based on 877 qualitative reports and 332 quantitative assessments from 89 different studies. Hundreds of reports of unusual species observations from around the world suggest that animals quickly responded to the reductions in human presence. However, negative effects of lockdown on conservation also emerged, as confinement resulted in some park officials being unable to perform conservation, restoration and enforcement tasks, resulting in local increases in illegal activities such as hunting. Overall, there is a complex mixture of positive and negative effects of the pandemic lockdown on nature, all of which have the potential to lead to cascading responses which in turn impact wildlife and nature conservation. While the net effect of the lockdown will need to be assessed over years as data becomes available and persistent effects emerge, immediate responses were detected across the world. Thus, initial qualitative and quantitative data arising from this serendipitous global quasi-experimental perturbation highlights the dual role that humans play in threatening and protecting species and ecosystems. Pathways to favorably tilt this delicate balance include reducing impacts and increasing conservation effectiveness.

Published
2021

31. Experimental travelling waves identification in mechanical structures.

Author

Bucher, Izhak, Gabai, Ran, Plat, Harel, Dolev, Amit, and Setter, Eyal

Subjects
STRUCTURAL mechanics, VIBRATION (Mechanics), STANDING waves, ENERGY transfer, FLUX (Energy)
Abstract

Vibrations are often represented as a sum of standing waves in space, i.e. normal modes of vibration. While this can be mathematically accurate, the representation as travelling waves can be compact and more appropriate from a physical point of view, in particular when the energy flux along the structure is meaningful. The quantification of travelling waves assists in computing the energy being transferred and propagated along a structure. It can provide local as well as global information about the structure through which the mechanical energy flows. Presented in this paper is a new method to quantify the fraction of mechanical power being transmitted in a vibration cycle at a specific direction in space using measured data. It is shown that the method can detect local defects causing slight non-uniformity of the energy flux. Equivalence is being made with the electrical power factor and electromagnetic standing waves ratio, commonly employed in such cases. Other methods to perform experiment based wave identification in one-dimension are compared with the power flow based identification. Including a signal processing approach that fits an ellipse to the complex amplitude curve and Hilbert transform for obtaining the local phase and amplitude. A new representation of the active and reactive power flow is developed and its relationship to standing waves ratio is demonstrated analytically and experimentally. [ABSTRACT FROM AUTHOR]

Published
2019
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36. Inference of the Activity Timeline of Cattle Foraging on a Mediterranean Woodland Using GPS and Pedometry.

Author

Ungar, Eugene D., Schoenbaum, Iris, Henkin, Zalmen, Dolev, Amit, Yehuda, Yehuda, and Brosh, Arieh

Subjects
PEDOMETERS, DISCRIMINANT analysis, CALIBRATION, GLOBAL Positioning System, DETECTORS
Abstract

The advent of the Global Positioning System (GPS) has transformed our ability to track livestock on rangelands. However, GPS data use would be greatly enhanced if we could also infer the activity timeline of an animal. We tested how well animal activity could be inferred from data provided by Lotek GPS collars, alone or in conjunction with IceRobotics IceTag pedometers. The collars provide motion and head position data, as well as location. The pedometers count steps, measure activity levels, and differentiate between standing and lying positions. We gathered synchronized data at 5-min resolution, from GPS collars, pedometers, and human observers, for free-grazing cattle (n = 9) at the Hatal Research Station in northern Israel. Equations for inferring activity during 5-min intervals (n = 1,475), classified as Graze, Rest (or Lie and Stand separately), and Travel were derived by discriminant and partition (classification tree) analysis of data from each device separately and from both together. When activity was classified as Graze, Rest and Travel, the lowest overall misclassification rate (10%) was obtained when data from both devices together were subjected to partition analysis; separate misclassification rates were 8, 12, and 3% for Graze, Rest and Travel, respectively. When Rest was subdivided into Lie and Stand, the lowest overall misclassification rate (10%) was again obtained when data from both devices together were subjected to partition analysis; misclassification rates were 6, 1, 26, and 17% for Graze, Lie, Stand, and Travel, respectively. The primary problem was confusion between Rest (or Stand) and Graze. Overall, the combination of Lotek GPS collars with IceRobotics IceTag pedometers was found superior to either device alone in inferring animal activity. [ABSTRACT FROM AUTHOR]

Published
2011
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