1,410 research outputs found
Type N Spacetimes as Solutions of Extended New Massive Gravity
We study algebraic type N spacetimes in the extended new massive gravity
(NMG), considering both the Born-Infeld model (BI-NMG) and the model of NMG
with any finite order curvature corrections. We show that for these spacetimes,
the field equations of BI-NMG take the form of the massive (tensorial)
Klein-Gordon type equation, just as it happens for ordinary NMG. This fact
enables us to obtain the type N solution to BI-NMG, utilizing the general type
N solution of NMG, earlier found in our work. We also obtain type N solutions
to NMG with all finite order curvature corrections and show that, in contrast
to BI-NMG, this model admits the critical point solutions, which are
counterparts of "logarithmic" AdS pp-waves solutions of NMG.Comment: 6 pages, twocolumn REVTe
The Effect of Recreational Physical Activity Training on Bio-motor Characteristics of Secondary School Students
The aim of this study was to investigate the effect of recreational physical activity training on biomotor characteristics of 12-age group secondary school students. A total of 116 physically inactive male students in secondary school participated in this study as healthy and volunteer. Participants were divided randomly into three groups: the recreational soccer training group (SG; n: 43; height: 146.51±9.01 cm; weight: 37.73±12.20 kg), the recreational volleyball training group (VG; n: 37; height: 146.97±7.19 cm; weight: 42.04±11.39 kg) and the control group (CG; n: 36; height: 141.53±8.27 cm; weight: 39.62±11.72 kg). SG and VG completed their recreational physical activities in 2 days a week for 24 weeks. The body composition, speed, agility, flexibility, strength, anaerobic power and aerobic power values were measured. The paired-samples t-test and one-way ANOVA with multiple comparisons were used for evaluations of the groups. The level of significance was used at 0.05. The results of the body composition and bio-motor capacities were significantly higher in favor of SG and VG than CG. In conclusion, recreational soccer and volleyball trainings may be proposed as entertaining physical activities that stimulate both body composition and bio-motor capacities
Flexible ceramic polymer composite substrates with spatially variable dielectrics for miniaturized RF applications
The goal of this research is to develop a process suitable for producing monolithic conformal substrates with a spatial arrangement of material cells according to a particular design creating novel material systems, useful for many multi- functional electronic and Radio Frequency devices. In this study, MCT ceramics (Mg-Ca-Ti-O systems) and organic binders (polymer solution) are mixed and fabricated as films through a process called tape casting to compromise between high dielectric constant and flexibility. Prior to optimizing the process, several characterization studies are carried out: Commercial spray dried MCT powders (Transtech Inc.) with dielectric constant k=70 and k=20 were analyzed as pressed and produced into tape cast films. Dielectric properties are then measured by an Agilent 16451B material analysis kit and their microscopic behavior is examined by scanning electron microscopy. Results show that flexible composite films show a maximum dielectric constant of e~22 unlike their powder pressed form with e ~16 but their loss behavior deteriorates when compared with their sintered form and a loss tangent factor of 0.001. The difference is attributed to the air content vs. polymer presence of the material in powder pressed form. Also, these substrates naturally are no longer flexible; hence studies are focused on their tape cast form. The potential of these dielectric shades to serve as candidate constituents for producing monolithic textured polymer-ceramic-composites with controllable loss is studied further. Four properties are of prime importance: tunability of dielectric constants to achieve miniaturization, flexibility via low temperature processing of polymers and loss controllability
The Effect of the Coach-Athlete Relationship on Passion for Sports: The Case of Male Handball Players in Super League
The purpose of this study is to reveal out the relationship between the team players' perceived coach-athlete relationship and their passion in sports. This is a research carried out with sectional screening model. The study group consisted of 200 male handball players in super league in Turkey. Participants were asked questions with demographic information to obtain personal information. Additionally, 11 question “Coach-Athlete Relationship Scale” developed by Jowett & Ntoumanis (2004) and adapted to Turkish by Altıntaş et al. (2012) and 12 question “Athlete Passion Scale” developed by Vallerand et al. (2003) and adapted to Turkish by Kelecek & Aşçı (2013) was applied. To evaluate the obtained data SPSS 20 package program was used and percentage (%), frequency (f), Kruskal Wallis test, correlation analysis, and regression analysis were conducted. There was a positive relationship between the coach-athlete relationship and its sub-dimensions of commitment, closeness and complementarity and also between the passion for sports and its sub-dimensions of harmonious passion and obsessive passion. Besides, the regression analysis has shown that the coach-athlete relationship has a relatively high impact on the passion for sports. In other words, as the effectiveness and quality of the coach-athlete relationship increase, so does "passion", which is one of the most important motivation sources for the athletes. At the end of our research it was found that, the coach-athlete relationship was at high level. As a result, there is a relationship between coach-athlete relationship and sport passion
Spectra, vacua and the unitarity of Lovelock gravity in D-dimensional AdS spacetimes
We explicitly confirm the expectation that generic Lovelock gravity in D
dimensions has a unitary massless spin-2 excitation around any one of its
constant curvature vacua just like the cosmological Einstein gravity. The
propagator of the theory reduces to that of Einstein's gravity, but scattering
amplitudes must be computed with an effective Newton's constant which we
provide. Tree-level unitarity imposes a single constraint on the parameters of
the theory yielding a wide range of unitary region. As an example, we
explicitly work out the details of the cubic Lovelock theory.Comment: 9 pages, 2 references adde
"İmparatorluğun Son Döneminde Osmanlı Ermenileri Konferansı" ve ifade özgürlüğü üzerine
Taha Toros Arşivi, Dosya Adı: Eğitimİstanbul Kalkınma Ajansı (TR10/14/YEN/0033) İstanbul Development Agency (TR10/14/YEN/0033
A novel 1.5 '' quadruple antenna for tri-band GPS applications
A new global positioning system (GPS) antenna is proposed to cover the three GPS bands (L1, L2, and L5, namely 1575, 1227, and 1176 MHz) with the L5 band to be added after 2006. The developed antenna size is only 1.5" x 1.5" in aperture corresponding to lambda/7 x lambda/7 (lambda = free space wavelength) and lambda/13 thick. Quadrature feeding is employed to ensure right-hand circular polarized (RHCP) radiation. The final miniature antenna exhibits a gain greater than 2 dBi, and to our knowledge this is the smallest such size for circular polarized (CP) operation covering all three bands. Detailed parametric simulations leading to the best design along with measurements for the constructed antenna are presented
Circularly polarized localized near-field radiation at the nanoscale
A novel nano-antenna configuration is suggested to achieve circularly polarized optical spots beyond the diffraction limit. Intense optical spots with circular polarization are obtained using a cross-dipole nano-antenna
Optimization of aperture coupled microstrip patch antennas
Aperture coupled microstrip patch antennas (ACMPA) are special class of microstrip antennas with high gain and wide impedance bandwidth. These antennas differ from other microstrip antennas with their feeding structure of the radiating patch element. Input signal couples to the radiating patch through the aperture that exists on the ground plane of the microstrip feedline. These special antennas are multilayer stacked type of antennas with so many design variables that will affect the antenna performance. This paper presents the design and optimization procedure of ACMPA while taking care of all possible design variables and parameters to get the highest possible antenna gain and minimum VSWR
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