139,437 research outputs found
High-Efficiency Gene Transfer into Adult Fish : a New Tool to Study Fin Regeneration
No full textZebrafish represents an excellent model to study the function of vertebrate genes (e.g., well-developed genetics, large number of mutants, and genomic sequencing in progress), inasmuch as we have tools to manipulate gene expression. Recent use of injected morpholinos in eggs provides a good method to " knockdown " gene expression in early development (Nasevicius and Ekker, 2000), and the "caged" RNA injected in eggs allows to overexpress a gene in a specific set of cells (Ando et al., 2001). However, a method to specifically modify gene expression in the juvenile or in the adult is still missing. Such a method would be a very powerful tool to understand gene function in differentiated tissues. We describe here an electroporation-based approach, which allows gene transfer in adult tissues. Its efficiency was assessed using a GFP (green fluorescent protein) dependent assay. We then used this method to disrupt the Fgf signalling pathway during the process of regeneration
A simple multiband printed bowtie antenna
No full textThis letter presents a new approach for the design of a multiresonant printed bowtie antenna. Several techniques were attempted to obtain one antenna which is operational in the 2, 3, and 5 GHz bands corresponding to many wireless applications. The idea of creating different slot configurations on different parts of a single antenna is the basic principle. A prototype of the final antenna design was fabricated tested and a good agreement was found between simulated and tested results. © 2008 IEEE.Balanis C. A., 2005, ANTENNA THEORY ANAL; Birch M, 2002, P SOC PHOTO-OPT INS, V4758, P573, DOI 10.1117-12.462195; Eldek AA, 2005, IEEE T ANTENN PROPAG, V53, P3067, DOI 10.1109-TAP.2005.851870; James J.R., 1989, IEE ELECTROMAGNETIC, V28; Karacolak T, 2006, IEEE ANTENN WIREL PR, V5, P446, DOI 10.1109-LAWP.2006.885013; Kiminami K, 2004, IEEE ANTENN WIREL PR, V3, P152, DOI 10.1109-LAWP.2004.832126; Lin YD, 1998, IEEE T ANTENN PROPAG, V46, P459; Nedil M., 2003, P CAN C EL COMP ENG, V3, P1433; Nishioka Y, 1999, IEEE T ANTENN PROPAG, V47, P970, DOI 10.1109-8.777119; TAWK Y, 2007, THESIS AM U BEIRUT L; Uduwawala D, 2004, IEEE T GEOSCI REMOTE, V42, P732, DOI 10.1109-TGRS.2003.819442; Yazdandoost K. Y., 2005, P IEEE WIRELESS COMM, P21282
Erratum: High-efficiency gene transfer into adult fish: A new tool to study fin regeneration (Genesis (January 2002) 32 (27-31))
No full textSpatially-localized time dependent solutions including turbulence and their interactions in 2D Kolmogorov flow
No full textIn 2D Kolmogorov flow in small aspect ratio domains, spatially-localized solutions such as kink, traveling or time-dependent kink-antikink pars coexist. However, the conservation of the flow rate in the y direction strongly restrict combination of localized solutions and their positioning. We find that by adding a homogeneous flow U y their positioning is controlled and each of localized solutions including a spatially-localized chaos is isolated. Numerical results suggest that these isolated solutions can be elements constructing a whole flow
Characteristics of overlap region in high-Reynolds number turbulent channel flow
No full textDirect numerical simulation of the fully developed turbulent channel flows have been carried out at the Reynolds number based on the friction velocity and the channel half width, 2000, 4000 and 8000. A hybrid 10th order accurate finite difference scheme in the stream and spanwise directions, and a second-order scheme in the wall-normal direction is adapted as the spatial discretization method. We observed the plateau profiles in the indicator function corresponded to the von Karman constant. Furthermore, second peak of streamwise pre-multiplied spectra were appeared in the same wall normal height, 300 < y+ < 600, in case of Re = 4000. Nevertheless, the effects of the lager than the channel half height scale on the streamwise turbulent intensity are fixed contributions without dependence on Reynolds number. These results suggested that the new streamwise vortexes are formed between buffer layer and outer layer with increasing of Reynolds number
La 'circunstancia' de 'Herederos y Pretendientes
No full textIn June 2010, the Ortega y Gasset Foundation hosted a Conference about the “Spanish Philosophical Transition” in order to debate the book of Francisco Vázquez, La filosofía española. Herederos y Pretendientes. Una lectura sociológica (1963-1990), recently published. This paper is the author’s response to criticism raised in the Conference and to published reviews received by this book. First, the author summarized the argument of Herederos y pretendientes. Secondly he responds and takes into account the most important objections against the book’s hypothesis and methodology. Finally the author evaluates the favorable judgments received by the book and suggests the limits of the historian’s task.Fundación Ortega y Gasset-Marañó
A new quadrifilar helix antenna for space communications
No full textThis paper presents a new quadrifilar helix antenna designed to deploy on a space craft for space communications. The quadrifilar helix is beryllium based and is deployed on top of a square ground plane. The ground plane is optimized to reduce back lobe radiation and achieve optimal gain and beam width. A trade off analysis is achieved and is discussed herein. The antenna dimensions and structure are studied to preserve operation in the S-band range while preserving stable radiation characteristics. © 2013 IEEE
A reconfigurable antenna with software controlled ground plane
No full textThis paper discusses an antenna design that achieves tuning of its frequency response by changing the height and angular position of its ground plane. The antenna is composed of a simple patch and three ground planes. Two ground planes are fixed while a third part moves and tilts based on the user's demand. The antenna's moving ground plane is controlled by an arduino board and two linear actuators. The antenna is simulated and measured. Good analogy is found between measured and simulated data. © 2013 IEEE
Author self-citation in orthodontics is associated with author origin and gender.
No full textBACKGROUND
The aims of this bibliometric study were to determine author self-citation trends in high-impact orthodontic literature and to investigate possible association between self-citation and publication characteristics.
METHODS
Six orthodontic journals with the highest impact factor as ranked by 2017 Journal Citation Reports were screened for a full publication year (2018) for original research articles, reviews, and case reports. Eligible articles were scrutinized for article and author characteristics and citation metrics. Univariable and multivariable negative binomial regression was used to examine associations between self-citation incidence and publication characteristics.
RESULTS
Medians for author self-citation rate of the most self-citing authors and self-citations were 3.03% (range 0-50) and 1 (range 0-19), respectively. In the univariable analysis, there was no association between self-citation counts and study type (P = 0.41), article topic (P = 0.61), number of authors (P = 0.62), and rank of authors (P = 0.56). Author origin (P = 0.001), gender (P = 0.001) and journal (P = 0.05) were associated with self-citation counts and in the multivariable analysis only origin and gender remained strong self-citation predictors. Asian authors and females self-cited significantly less often than all other regions and male authors.
CONCLUSIONS
Authors in orthodontics do not self-cite at a frequency that suggests potential citation manipulation. Author origin and gender were the only variables associated with citations counts. More bibliometric research is necessary to draw solid conclusions about author self-citation trends in orthodontic literature
A low-cost microstrip antenna for 3G-WLAN-WiMAX and UWB applications
No full textThis paper presents a low-cost ultra-wideband microstrip antenna for wireless communications. Printed on a 40×50×1.83 mm3 Isola Gigaver 210 substrate, the antenna features a microstrip feed line with two 45° bends and a tapered section for size reduction and matching, respectively. The ground plane is partial and comprises a rectangular part and a trapezoidal part. The patch is a half ellipse, where the cut is made along the minor axis. Several slots are incorporated into the patch. The placement and sizes of the slots are assisted by the knowledge of fractal geometries . The return loss, input impedance, gain, efficiency and radiation characteristics of the antenna are presented. It is shown that the antenna can operate in the bands used for UMTS, WLAN, WiMAX, and UWB applications. © 2009 IEEE.*AG TECHN, ADS MOM 2006; Al-Husseini M., 2008, 2008 INT WIR COMM MO; ALHUSSEINI M, 2009, 26 NAT RAD SCI C NRS; Balanis C. A., 2005, ANTENNA THEORY ANAL; El-Khamy S. E., 2004, 21 NAT RAD SCI C NRS, P1; Kumar G., 2003, BROADBAND MICROSTRIP; Low ZN, 2005, IEEE ANTENN WIREL PR, V4, P237, DOI 10.1109-LAWP.2005.852577; Werner DH, 2003, IEEE ANTENN PROPAG M, V45, P38, DOI 10.1109-MAP.2003.1189650; Zhang JP, 2008, IEEE T ANTENN PROPAG, V56, P241, DOI 10.1109-TAP.2007.91316510
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