5,570 research outputs found
Associations among neighborhood socioeconomic deprivation, physical activity facilities, and physical activity in youth during the transition from childhood to adolescence
BACKGROUND: This study aims to examine the longitudinal association of neighborhood socioeconomic deprivation (SED) with physical activity in youth during the transition from elementary to middle school, and to determine if access to physical activity facilities moderates this relationship.
METHODS: Data were obtained from the Transitions and Activity Changes in Kids (TRACK) study, which was a multilevel, longitudinal study designed to identify the factors that influence changes in physical activity as youth transition from elementary to middle school. The analytic sample for the current study included 660 youth with complete data in grades 5 (baseline) and 7 (follow-up). A repeated measures multilevel framework was employed to examine the relationship between SED and physical activity over time and the potential moderating role of elements of the built environment.
RESULTS: Decreases in physical activity varied by the degree of neighborhood SED with youth residing in the most deprived neighborhoods experiencing the greatest declines in physical activity. Access to supportive physical activity facilities did not moderate this relationship.
CONCLUSION: Future research studies are needed to better understand how neighborhood SED influences youth physical activity over time
Thermodynamics of spin-orbit-coupled Bose-Einstein condensates
In this paper we develop a quantum field approach to reveal the thermodynamic
properties of the trapped BEC with the equal Rashba and Dresselhaus spin-orbit
couplings. In the experimentally-feasible regime, the phase transition from the
separate phase to the single minimum phase can be well driven by the tunable
temperature. Moreover, the critical temperature, which is independent of the
trapped potential, can be derived exactly. At the critical point, the specific
heat has a large jump and can be thus regarded as a promising candidate to
detect this temperature-driven phase transition. In addition, we obtain the
analytical expressions for the specific heat and the entropy in the different
phases. In the single minimum phase, the specific heat as well as the entropy
are governed only by the Rabi frequency. However, in the separate phase with
lower temperature, we find that they are determined only by the strength of
spin-orbit coupling. Finally, the effect of the effective atom interaction is
also addressed. In the separate phase, this effective atom interaction affects
dramatically on the critical temperature and the corresponding thermodynamic
properties.Comment: 8 pages, 6 figure
Open Gromov-Witten Invariants of Toric Calabi-Yau 3-Folds
We present a proof of the mirror conjecture of Aganagic-Vafa
[arXiv:hep-th/0012041] and Aganagic-Klemm-Vafa [arXiv:hep-th/0105045] on disk
enumeration in toric Calabi-Yau 3-folds for all smooth semi-projective toric
Calabi-Yau 3-folds. We consider both inner and outer branes, at arbitrary
framing. In particular, we recover previous results on the conjecture for (i)
an inner brane at zero framing in the total space of the canonical line bundle
of the projective plane (Graber-Zaslow [arXiv:hep-th/0109075]), (ii) an outer
brane at arbitrary framing in the resolved conifold (Zhou [arXiv:1001.0447]),
and (iii) an outer brane at zero framing in the total space of the canonical
line bundle of the projective plane (Brini [arXiv:1102.0281, Section 5.3]).Comment: 39 pages, 11 figure
The Relationship of Creativity Domains with Personality Traits and Academic Environment in Higher Education
Creativity assessment is the cornerstone of effective creativity development in higher education It is one of the main topics in creativity research as it is one of the most difficult skill to measure in any of the 21 st century skills We argue that in additions to the big five creativity in higher education is related to the environment and that more research is needed to understand this relations Therefore this study aimed to investigate this relations specifically creativity domain with personality traits and the academic environment Measures for these constructs were administered to 103 Malaysian undergraduate students In order to examine the nature of the relations between creative personality and other constructs we used Structural Equation Modeling The results indicate that the model is valid and reliable for assessing the creative person of higher education students This study showed that both personality traits and academic environment are important to assess the creative personalit
A CFD Simulation of 3D Air Flow and Temperature Variation in Refrigeration Cabinet
Presented is a 3D simulation of the air flow and temperature variation in an ice drink refrigeration cabinet, during an automated dynamic cycle of switching on and switching off. To correctly model the effect of perforated plate separating evaporator and storage compartments, a benchmark problem is designed, and used as a reference to determine the parameters in the porous-jump model by parameter optimization. Subsequently, the dynamic cycle of initial switch on, automated switch off and automated switch on is simulated. Both the flow field distribution and temperature profile are analyzed and the time required for these three stages is obtained. Full 3D CFD simulation of refrigeration system provides not only detailed temperature distribution in the cabinet but also operational parameters of the system such as for switch on-off cycle. Those output from simulation are important for cabinet design to improve the storage quality of products while reducing the energy use
Sintesis Dan Karakterisasi Lapisan Radar Absorbing Material (RAM) Berbahan Dasar BaM/PANi Pada Rentang Gelombang X-Band Dengan Variasi Ketebalan
Sintesis dan Karakterisasi Lapisan Radar Absorbing Material (RAM) telah berhasil dilakukan. Penelitian ini bertujuan untuk mengidentifikasi sifat magnetik dari Barium M-Heksaferit yang didoping dengan ion Zn (Seng).Campuran dari Polianilin dan Barium M-Heksaferit digunakan sebagai Radar Absorbing Material (RAM). Prekursor dari ion besi dapat diperoleh dari maerial alamiah yakni pasir besi dari Tanah Laut Kalimantan Selatan. Dalam penelitian ini lapisan RAM terbuat dari komposit BaM/PANi dimana material BaM disintesis dengan menggunakan metode kopresipitasi. Komposit BaM/PANi yang telah dicampur dengan cat, dilapiskan pada permukaan baja AH36. Dalam penelitian ini variasi yang digunakan yaitu ketebalan lapisan (1 mm; 1,5 mm; 2 mm; 2,5 mm; dan 3 mm). Dari penelitian ini diperoleh material Barium M-Heksaferit yang bersifat hard magnetik dapat tereduksi setelah adanya pendopingan, hal tersebut dibuktikan dengan nilai medan koersivitas yang menurun yaitu sebesar 0,25 T. Material PANI dapat dikatakan polimer konduktif dikarenakan PANi memiliki nilai konduktivitas yang paling tinggi yakni sebesar 0,165 s/m. Nilai reflection loss terbesar dihasilkan oleh pelapisan single layer dengan ketebalan 3 mm yaitu sebesar -21,231 dB pada frekuensi 11,5 GHz. Pengaruh ketebalan terhadap nilai reflection loss yaitu semakin tebal lapisan komposit BaM/PANi yang dilapiskan pada plat baja maka akan semakin besar nilai reflection lossnya
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