697,485 research outputs found
THE EFFECTIVENESS OF A COMPUTER AND INTERNET-BASED SYSTEM IN A SHORT-TERM BEHAVIORAL WEIGHT LOSS INTERVENTION
THE EFFECTIVENESS OF A COMPUTER AND INTERNET-BASED SYSTEM IN A SHORT-TERM BEHAVIORAL WEIGHT LOSS INTERVENTIONKristen M. Polzien, PhD.University of Pittsburgh, 2005Computer and Internet-assisted weight loss interventions offer alternative delivery channels that might increase program appeal and potentially increase weight loss success. To date research focused on these innovative techniques is limited. PURPOSE: To examine the effectiveness adding a technology-based intervention component to an in-person, 12-week clinically-based behavioral weight loss intervention. METHODS: Fifty-seven subjects (body mass index = 33.1+/-2.8 kg/m2; age = 41.3+/-8.7 yrs) participated in a 12-week intervention with random assignment to Standard Behavioral Program (SBWP), Intermittent Technology-Based Program (INT-TECH), or Continuous Technology-Based Program (CON-TECH). SBWP received an individual weight loss session at weeks 1-4, 6, 8, and 10, prescribed a diet of 1200-1500 kcal/d, and exercise progressing from 20-40 min/d on 5 days/wk. INT-TECH and CON-TECH received the components of SBWP, however, these groups also used a SenseWear Pro Armband (BodyMedia, Inc.) to monitor energy expenditure and a web-based program to monitor eating behaviors. INT-TECH used these features during weeks 1, 5, and 9, with CON-TECH using these features throughout the 12-week intervention. Outcomes included body weight, percent body fat, and cardiorespiratory fitness. RESULTS: Fifty subjects completed the investigation (88%). Intent-to-treat analysis revealed weight loss of 4.1+/-2.8 kg (4.6 +/-2.8%), 3.4+/-3.4 kg (3.8+/-3.8%), and 6.2+/-4.0 kg (7.1+/-4.6%), for the SBWP, INT-TECH, and CON-TECH groups, respectively (CON-TECH greater than INT-TECH, p less than/equal to 0.05). Percent body fat was significantly decreased in CON-TECH (-4.1+/-2.9%) when compared to both SBWP (-1.6+/-1.5%) and INT-TECH (-1.6+/-1.7%) (p less than/equal to 0.05). Cardiorespiratory fitness significantly increased in all groups by 14%, 3%, and 5% in SBWP, INT-TECH, and CON-TECH, respectively; p less than 0.01), with no significant group differences. CONCLUSIONS: Results indicate that a technology-based program that is used continuous over a 12-week intervention and is complimentary to a clinically-based in-person intervention improves weight loss by approximately 3% compared to a SBWP that does not use these technology features or by approximately 3.7% compare to INT-TECH uses the technology features only intermittently during the intervention. Considering these short-term results, future studies should examine the impact of adding these technology features to a SBWP on long-term weight loss outcomes, and for whom technology-based programs are most effective
The Time of Flight System of the AMS-02 Space Experiment
The Time-of-Flight (TOF) system of the AMS detector gives the fast trigger to
the read out electronics and measures velocity, direction and charge of the
crossing particles. The new version of the detector (called AMS-02) will be
installed on the International Space Station on March 2004. The fringing field
of the AMS-02 superconducting magnet is kG where the
photomultiplers (PM) are installed. In order to be able to operate with this
residual field, a new type of PM was chosen and the mechanical design was
constrained by requiring to minimize the angle between the magnetic field
vector and the PM axis. Due to strong field and to the curved light guides, the
time resolution will be ps, while the new electronics will allow
for a better charge measurement.Comment: 5 pages, 4 figures. Proc. of 7th Int. Conf. on Adv. Tech. and Part.
Phys., 15-19 October 2001,Como (Italy
Diradicals and their driving forces
Several series of aromatic and quinoidal compounds, such as oligothiophenes (Scheme 1), oligophenylene-vinylenes, oligoperylenes (oligophenyls) and graphene nanoribbon derivatives, are studied in the common context of the capability to stabilize diradical structures. [1,2,3,4]. In this work, we try to clarify how several driving forces (i.e., thermodynamic and entropic) are responsible for the generation of diradical and diradicaloid structures. A combination of different types of molecular spectroscopies (i.e., electronic absorption, electronic emission, excited state absorption, vibrational Raman, vibrational infrared, etc.) as well as hybridized with thermal and pressure-dependent techniques are shown to provide important information about the origin of the formation and stabilization of diradicals. From a conceptual point of view, we analyze these properties in the context of the oligomer approach which is the study of the evolution of these spectroscopic quantities as a function of the oligomer size.
References
[1] P. Mayorga Burrezo, J.L. Zafra, J. Casado. Angew. Chem. Int. Ed., 2017, 56, 2250.
[2] J. Casado, R. Ponce Ortiz, J. T. Lopez Navarrete, Chem. Soc. Rev. 2012, 41, 5672.
[3] P. Mayorga Burrezo, X. Zhu, S. F. Zhu, Q. Yan, J. T. Lopez Navarrete, H. Tsuji, E. Nakamura, J. Casado, J. Am. Chem. Soc. 2015, 137, 3834-3843.
[4] J. Casado, Para-quinodimethanes: A unified review of the quinoidal-versus-aromatic competition and its implications. Top. Curr. Chem. 2017, 375, 73.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Moving Signals and Their Measured Frequencies
In determining the classical Doppler Effect, two assumptions are used for
computing the difference in distance travelled by consecutive signals: (a) the
receptor is stationary, and (b) the emitter is stationary. The calculated
Doppler Effect under the two assumptions are identical, provided the velocity
of propagation with respect to source and the velocity of propagation with
respect to the receptor differ exactly by the velocity of relative motion. We
show that, in the case of light, the ratio of the two calculated classical
Doppler Effects, with propagation speed c in the source and receptor inertial
frames respectively, remains constant in all geometries and orientations.
Furthermore, the observed Doppler Effect, as predicted by special relativity,
is the geometric mean of the two expected classical Doppler Effects in all
geometries and orientations. This leads to two simultaneous conclusions: (1) by
the receptor that the clock associated with the emitter runs slow, and (2) by
the emitter that the clock associated with the receptor runs slow. These
differences can be resolved if we theorize that light travels at speed c with
respect to the emitter as it leaves the emitter and travels at speed c with
respect to the receptor as it approaches the receptor.Comment: Revised in accordance with peer review process; Published August 2013
in Int. J. Engg. Res. & Sci & Tech 2(3) pp 24-3
Cyclic Triindoles and Tetraindoles: Substituent and Symmetry Effects on their Structural and Electronic Characteristics
During the last decade heptacyclic 10,15-dihydro-5H-diindolo[3,2-a:3',2'-c]carbazole (triindole) has been extensively studied as a new π-conjugated platform in the construction of self-assembling materials for optoelectronics. Specially remarkably is the record hole mobility values determined on triindole liquid crystals.1 In order to facilitate the design of new materials on a molecular basis and establish clear guidelines to fine tuning electronic parameters, we have recently synthesized new triindole and tetraindole-based systems.2-3 Our joint experimental and theoretical investigation shows that N-substitution, symmetry lowering of the platform, and insertion of π-spacers in extended dimers strongly impact on the fundamental electronic properties of triindoles.2 In addition, saddle-shaped tetraindoles are found to be an interesting 3D rigid scaffold to obtain electroactive molecules with increased dimensionality.3 We hope that this study can not only advance useful structure-property relationships of conjugated indole-based systems but also guide the design of new materials with potential applications in organic electronics.References
1. E.M. García-Frutos, U.K. Pandey, R. Termine, A. Omenat, J. Barberá, J.L. Serrano, A. Golemme, B. Gómez-Lor, Angew. Chem. Int. Ed. 2011, 50, 7399
2. a) C. Ruiz, J.T. López Navarrete, M.C.Ruiz Delgado, B. Gómez-Lor, Org. Lett. 2015, 17, 2258−2261. b) C. Ruiz, E.M. García-Frutos, D.A. da Silva Filho, J.T. López Navarrete, M.C. Ruiz Delgado, and B. Gómez-Lor, J. Phys. Chem. C 2014, 118, 5470−5477
3. C. Ruiz, A. Monge, E. Gutiérrez-Puebla, I. Alkorta, J. Elguero, J. T. López Navarrete, M.C. Ruiz Delgado and B. Gómez-Lor, submittedUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
[n]cycloparaphenylenes with charges
Oligophenylenes (polyphenylenes) are constituted by an array of conjugated benzenes where inter-ring electron delocalization tends to extend over the whole chain (linear conjugation) being intrinsically limited, among other factors, by terminal effects. Alternatively, cyclic conjugation is envisaged as the unlimited free-boundary versionofconjugation which will impact the structure of molecules in rather unknown ways. The cyclic version of oligophenylenes, cycloparaphenylenes ([n]CPPs with n the number of phenyl rings) were first synthesized in 2008 by Beztozzi and Jasti.1 Today the whole [n]CPP series from [5]CPP to [18]CPP has been prepared. [n]CPPs represent ideal models to investigate new insights of the electronic structure of molecules and cyclic conjugation when electrons or charges circulate in a closed circuit without boundaries. Radical cations and dications of [n]CPP from n=5 to n=12 have been prepared and studied by Raman spectroscopy.2 Small [n]CPP dications own their stability to the closed-shell electronic configuration imposed by cyclic conjugation. However, in large [n]CPP dications cyclic conjugation is minimal and these divalent species form open-shell biradicals. The Raman spectra reflect the effect of cyclic conjugation in competition with cyclic strain and biradicaloid aromatic stabilization. Cyclic conjugation provokes the existence of a turning point or V-shape behavior of the frequencies of the G bands as a function of n. In this communication we will show the vibrational spectroscopic fingerprint of this rare form of conjugation.
[1] R. Jasti, J. Bhattacharjee, J. B. Neaton, C. R. Bertozzi, “Synthesis, Characterization, and Theory of [9]-, [12]-, and [18]Cycloparaphenylene: Carbon Nanohoop Structures”, J. Am. Chem. Soc. 130 (2008), 17646–17647.
[2] M. P. Alvarez, P. M. Burrezo, M. Kertesz, T. Iwamoto, S. Yamago, J. Xia, R. Jasti, J. T. L. Navarrete, M. Taravillo, V. G. Baonza, J. Casado, “Properties of Sizeable [n]CycloParaPhenylenes As Molecular Models of Single-Wall Carbon Nanotubes By Raman Spectroscopy: Structural and Electron-Transfer Responses Under Mechanical Stress”, Angew. Chem. Int. Ed. 53, (2014), 7033−7037.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Systematic study on work-function-shift in metal/Hf-based high-k gate stacks
Change in the work function (WF) of the gate electrode material caused by the contact with Hf-based high-k gate dielectrics was investigated by means of the flat-band voltage (Vfb) shift in capacitance-voltage curves, and the interface dipole, which modifies the WF, was characterized by x-ray photoelectron spectroscopy. We observed a negative Vfb shift and corresponding interface dipole, which suggest the formation of oxygen vacancy (VO) in the Hf-based oxides. In contrast, we observed an opposite (positive) Vfb shift and interface dipole when Au electrodes were formed on cleaned Hf-based dielectrics. This indicates that Au–Hf bond hybridization at the Au/HfSiON interface also causes effective WF modulation, as theoretically predicted by Shiraishi et al. (Tech. - Dig. Int. Electron Devices Meet. 2005, 43)
Simulation of bridge die extrusion using the finite element method
This communication reviews previous work on the extrusion of hollow shapes and uses a three-dimensional (FEM) solution to predict load-required, temperature of the extrudate and material flow during the process. A comparison with experiments is made to assess the relative importance of some extrusion parameters in the extrusion process and to ensure that the numerical discretisation yields a realistic simulation of the process. The usefulness and limitations of FEM when modelling complex shapes is also discussed. Methods to assess the difficulty of extrusion of hollow extrusions in general are presented. The paper also illustrates the essentials of numerical analysis to assist the reader in the comprehension of the thermomechanical events occurring during extrusion through bridge dies. Results are presented for velocity distribution in the extrusion chamber, iso-temperature contours and pressure/ displacement traces. These are compared with experiments conducted using a 5 MN press. It is shown that the finite element program predicts the pressure requirement: the pressure/displacement trace showing a double peak which is discussed in some detail. The finite element program appears to predict all the major characteristics of the flow observed macroscopically
VAN LCOS microdisplays: a decade of technological evolution
Abstract—Microdisplays of the liquid crystals on silicon (LCOS)
type have gone through a rapid evolution during the last decade.
We present an overview of how vertically aligned nematic (VAN) LCOS have evolved from an attractive, but notoriously difficult and even infamous technology, to the mainstream microdisplay technology that it is today. At the same time, we highlight a number of remaining issues and concerns, and present some ideas of how to remedy them
A fully integrated 24-GHz phased-array transmitter in CMOS
This paper presents the first fully integrated 24-GHz phased-array transmitter designed using 0.18-/spl mu/m CMOS transistors. The four-element array includes four on-chip CMOS power amplifiers, with outputs matched to 50 /spl Omega/, that are each capable of generating up to 14.5 dBm of output power at 24 GHz. The heterodyne transmitter has a two-step quadrature up-conversion architecture with local oscillator (LO) frequencies of 4.8 and 19.2 GHz, which are generated by an on-chip frequency synthesizer. Four-bit LO path phase shifting is implemented in each element at 19.2 GHz, and the transmitter achieves a peak-to-null ratio of 23 dB with raw beam-steering resolution of 7/spl deg/ for radiation normal to the array. The transmitter can support data rates of 500 Mb/s on each channel (with BPSK modulation) and occupies 6.8 mm /spl times/ 2.1 mm of die area
- …
