1,234 research outputs found
PKE–Nefedov*: plasma crystal experiments on the International Space Station
No full textAbstract. The plasma crystal experiment PKE–Nefedov, the first basic science experiment on the International Space Station (ISS), was installed in February 2001 by the first permanent crew. It is designed for long-term investigations of complex plasmas under microgravity conditions. ‘Complex plasmas ’ contain ions, electrons, neutrals and small solid particles—normally in the micrometre range. These microparticles obtain thousands of elementary charges and interact with each other via a ‘screened ’ Coulomb potential. Complex plasmas are of special interest, because they can form liquid and crystalline states (Thoma
Database Theory, Yuri, and Me
No full textYuri Gurevich made many varied and deep contributions to logic for computer science. Logic provides also the theoretical foundation of database systems. Hence, it is almost unavoidable that Gurevich made some great contributions to database theory. We discuss some of these contributions, and, along the way, present some personal anecdotes connected to Yuri and the author. We also describe the honorary doctorate awarded to Gurevich by Hasselt University (then called Limburgs Universitair Centrum) in 1998
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PKE-Nefedov*: Plasma crystal experiments on the International Space Station
No full textThe plasma crystal experiment PKE-Nefedov, the first basic science experiment on the International Space Station (ISS), was installed in February 2001 by the first permanent crew. It is designed for long-term investigations of complex plasmas under microgravity conditions. 'Complex plasmas' contain ions, electrons, neutrals and small solid particles - normally in the micrometre range. These microparticles obtain thousands of elementary charges and interact with each other via a 'screened' Coulomb potential. Complex plasmas are of special interest, because they can form liquid and crystalline states (Thomas et al 1994 Phys. Rev. Lett. 73 652-5, Chu and I 1994 Phys. Rev. Lett. 72 4009-12) and are observable at the kinetic level. In experiments on Earth the microparticles are usually suspended against gravity in strong electric fields. This creates asymmetries, stresses and pseudo-equilibrium states with sufficient free energy to readily become unstable. Under microgravity conditions the microparticles move into the bulk of the plasma (Morfill et al 1999 Phys. Rev. Lett. 83 1598), experiencing much weaker volume forces than on Earth. This allows investigations of the thermodynamics of strongly coupled plasma states under substantially stress-free conditions. In this first paper we report our results on plasma crystals, in particular the first experimental observations of bcc lattice structures
YURI KOUZNETSOV AND POLAND
No full textThis article analyses a translation of one of Adam Mickiewicz’s Sonnets from the Crimea made by Yuri Kouznetsov, a famous Russian poet. It is not incidental that some Polish toponyms coincide with personal names mentioned in Kouznetsov’s poetry. The author of the article examines the system of symbols that Kouznetsov resorts to in his texts concerning either Polish themes or stories. It is concluded that in one of his philosophical verses Kouznetsov proclaimed Polish and German culture to have messianic value
Yuri Apollonovich Ptashkovsky (1948—2015)
No full textYuri Apollonovich Ptashkovsky (Юрий Аполлонович Пташковский, in Russian) was born on April 4, 1948, in Khmelnytskyi, Ukraine, and spent most of his life there. He studied at the Khmelnytskyi Electromechanical College, specializing as an electrical technician. He later worked as head of the cinema-photo laboratory of the Khmelnytskyi Municipal Palace of Culture and also led the Children’s Photography Club. Despite his technical education, Yuri’s devotion to nature and studies of nature were evident from his early years. From young age, he passionately observed and investigated insects, especially beetles. Yuri started his own private beetle collection at the age of fourteen. He carefully mounted the specimens for his collection and identified them using available entomological literature. By 1978, his collection amounted to about 1,500 species of beetles. ...Yuri came to Israel on October 28, 1998, joining his eldest son, who was already living in Kibbutz Malkiyya. Yuri settled in Qiryat Hayyim, one of the northern suburbs of Haifa, where he remained for the rest of his life. He worked as a geodesist for the Jewish National Fund (KKL) until his retirement in 2013. From his very first steps in the country, Yuri became fascinated by the incredible diversity of the local beetle fauna, and immediately began collecting insects. Many of his field trips were in and around Qiryat Hayyim, in surrounding fields, and in marine dunes, although he also collected in other parts of the country, particularly in the Upper Galilee, Golan Heights, and on Mount Hermon. Working as a geodesist for KKL, he traveled regularly across northern Israel and was able to assemble a valuable collection of beetles and to photograph them in their natural environment. When the number of his photographed species exceeded 1,000, Yuri came up with the idea of making an illustrated atlas of Israeli Coleoptera.In 2009, after eight years of intensive work the atlas—the first of its kind—was published. The first edition was in Russian and Hebrew, with only a few printed copies. The second edition of 50 copies was published in 2013 in English, with Russian and Hebrew names of some beetle taxa. The atlas is illustrated with 1,800 color images of 1,655 beetle species, some of them taken by the author and some borrowed from various sources. Some of the taxa are briefly described, others are only mentioned by name and by distribution; identification guidelines and sketches are provided for some species and genera. The books were published at Yuri’s own expense. Over the last few years, Yuri began to work on a third edition of his atlas, but his untimely death has interrupted this admirable endeavor. Yuri passed away unexpectedly, from a stroke, on February 9, 2015. He is survived by his wife Galina, two sons and a daughter.
Cite as: Friedman, A.-L.-L. & Novikova, A.V. 2016. Yuri Apollonovich Ptashkovsky (1948—2015). Israel Journal of Entomology 46: 137–140.
DOI: 10.5281/zenodo.22110
Letter from Yuri to Mr. Bengston, October 12, 1942
No full textPost-WWII, Pollock maintains various correspondence with folks from the Fresno Assembly Center, as well as other correspondence with the Pentagon.Walter E. Pollock was the head of the service division at the Fresno Assembly Center. He was deeply affected by his time working at the center and was working on a memoir of his experiences there, but unfortunately passed away before it could be completed. The collection contains his research and draft chapters
Letter from Yuri to Mr. Bengston, September 30, 1942
No full textPost-WWII, Pollock maintains various correspondence with folks from the Fresno Assembly Center, as well as other correspondence with the Pentagon.Walter E. Pollock was the head of the service division at the Fresno Assembly Center. He was deeply affected by his time working at the center and was working on a memoir of his experiences there, but unfortunately passed away before it could be completed. The collection contains his research and draft chapters
Yuri Apollonovich Ptashkovsky (1948—2015)
No full textYuri Apollonovich Ptashkovsky (Юрий Аполлонович Пташковский, in Russian) was born on April 4, 1948, in Khmelnytskyi, Ukraine, and spent most of his life there. He studied at the Khmelnytskyi Electromechanical College, specializing as an electrical technician. He later worked as head of the cinema-photo laboratory of the Khmelnytskyi Municipal Palace of Culture and also led the Children’s Photography Club.
Despite his technical education, Yuri’s devotion to nature and studies of nature were evident from his early years. From young age, he passionately observed and investigated insects, especially beetles. Yuri started his own private beetle collection at the age of fourteen. He carefully mounted the specimens for his collection and identified them using available entomological literature. By 1978, his collection amounted to about 1,500 species of beetles. ...
Yuri came to Israel on October 28, 1998, joining his eldest son, who was already living in Kibbutz Malkiyya. Yuri settled in Qiryat Hayyim, one of the northern suburbs of Haifa, where he remained for the rest of his life. He worked as a geodesist for the Jewish National Fund (KKL) until his retirement in 2013. From his very first steps in the country, Yuri became fascinated by the incredible diversity of the local beetle fauna, and immediately began collecting insects. Many of his field trips were in and around Qiryat Hayyim, in surrounding fields, and in marine dunes, although he also collected in other parts of the country, particularly in the Upper Galilee, Golan Heights, and on Mount Hermon. Working as a geodesist for KKL, he traveled regularly across northern Israel and was able to assemble a valuable collection of beetles and to photograph them in their natural environment. When the number of his photographed species exceeded 1,000, Yuri came up with the idea of making an illustrated atlas of Israeli Coleoptera.
In 2009, after eight years of intensive work the atlas—the first of its kind—was published. The first edition was in Russian and Hebrew, with only a few printed copies. The second edition of 50 copies was published in 2013 in English, with Russian and Hebrew names of some beetle taxa. The atlas is illustrated with 1,800 color images of 1,655 beetle species, some of them taken by the author and some borrowed from various sources. Some of the taxa are briefly described, others are only mentioned by name and by distribution; identification guidelines and sketches are provided for some species and genera. The books were published at Yuri’s own expense. Over the last few years, Yuri began to work on a third edition of his atlas, but his untimely death has interrupted this admirable endeavor.
Yuri passed away unexpectedly, from a stroke, on February 9, 2015. He is survived by his wife Galina, two sons and a daughter. ..
A Guiding Vector-Field algorithm for path-following control of nonholonomic mobile robots
No full textIn this paper, we propose an algorithm for path-following control of the nonholonomic mobile robot based on the idea of the guiding vector field (GVF). The desired path may be an arbitrary smooth curve in its implicit form, that is, a level set of a predefined smooth function. Using this function and the robot's kinematic model, we design a GVF, whose integral curves converge to the trajectory. A nonlinear motion controller is then proposed, which steers the robot along such an integral curve, bringing it to the desired path. We establish global convergence conditions for our algorithm and demonstrate its applicability and performance by experiments with wheeled robots.Accepted Author ManuscriptTeam Tamas Keviczk
Effects of Participatory and Physical Life Goals in a Preventive Care Program for Frail Community-Dwelling Older People: A Retrospective Cohort Study
No full textAbstract
Date Presented 3/31/2017
Life goals related to activities and participation had a more positive effect on frail older people’s health and quality of life than did life goals related to physical function and structure. The setting of meaningful goals may help to improve the effectiveness of preventive care programs.
Primary Author and Speaker: Yoshimi Yuri
Additional Authors and Speakers: Shinichi Takabatake, Yoko Tsuji, Yuri Fujii, Toshikatsu Kaneda, Yasuhiro Higashi, Hiroko Hashimoto, Kazuyo Nakaoka, Mari Oka</jats:p
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