296 research outputs found
Sphere rolling on the surface of a cone
We analyse the motion of a sphere that rolls without slipping on a conical
surface having its axis in the direction of the constant gravitational field of
the Earth. This nonholonomic system admits a solution in terms of quadratures.
We exhibit that the only circular of the system orbit is stable and furthermore
show that all its solutions can be found using an analogy with central force
problems. We also discuss the case of motion with no gravitational field, that
is, of motion on a freely falling cone.Comment: 12 pages, 2 figures, to be published in Eur J Phy
Short-term morphological changes in asymptomatic perimandibular muscles after dry needling assessed with rehabilitative ultrasound imaging: A proof-of-concept study
Facial anatomical structures are not easily accessible to manual palpation. The aim of our study is to objectively assess temporomandibular joint and perimandibular muscles dimensions by means of sonographic measurements before and after dry needling (DN) in asymptomatic subjects. Seventeen subjects participated in this before-after study with a within-subject control. After random allocation, one side of the face was used for the intervention and the contralateral as control. DN was performed on the temporal, masseter, and sternocleidomastoid muscles. Each subject was examined bilaterally before, immediately after, and one month after the intervention through Rehabilitative Ultrasound Imaging (RUSI) of the temporomandibular articular disc and the three target muscles. Maximum mouth opening was measured at baseline and at one month. After a single DN session, articular disc thickness significantly decreased; muscles' thicknesses (except for temporal thickness) significantly decreased immediately and at follow-up on the treated side; no significant changes resulted for the control side. The maximum mouth opening increased from 4.77 mm to 4.86 mm. RUSI may be useful to assess the dimensions and thickness of the temporomandibular disc and muscles before and after an intervention. DN influences muscle morphology, and it has a positive influence on mouth opening in the short term
T-duality in Massive Integrable Field Theories: The Homogeneous and Complex sine-Gordon Models
The T-duality symmetries of a family of two-dimensional massive integrable
field theories defined in terms of asymmetric gauged Wess-Zumino-Novikov-Witten
actions modified by a potential are investigated. These theories are examples
of massive non-linear sigma models and, in general, T-duality relates two
different dual sigma models perturbed by the same potential. When the
unperturbed theory is self-dual, the duality transformation relates two
perturbations of the same sigma model involving different potentials. Examples
of this type are provided by the Homogeneous sine-Gordon theories, associated
with cosets of the form G/U(1)^r where G is a compact simple Lie group of rank
r. They exhibit a duality transformation for each element of the Weyl group of
G that relates two different phases of the model. On-shell, T-duality provides
a map between the solutions to the equations of motion of the dual models that
changes Noether soliton charges into topological ones. This map is carefully
studied in the complex sine-Gordon model, where it motivates the construction
of Bogomol'nyi-like bounds for the energy that provide a novel characterisation
of the already known one-solitons solutions where their classical stability
becomes explicit.Comment: 29 pages, LaTe
Imaging with ultrasound in physical therapy: What is the PT’s scope of practice? A competency-based educational model and training recommendations.
Physical therapists employ ultrasound (US) imaging
technology for a broad range of clinical and research
purposes. Despite this, few physical therapy regulatory
bodies guide the use of US imaging, and there are
limited continuing education opportunities for physical
therapists to become proficient in using US within
their professional scope of practice. Here, we (i) outline
the current status of US use by physical therapists; (ii)
define and describe four broad categories of physical
therapy US applications (ie, rehabilitation, diagnostic,
intervention and research US); (iii) discuss how US
use relates to the scope of high value physical therapy
practice and (iv) propose a broad framework for a
competency-based
education model for training physical
therapists in US. This paper only discusses US imaging—
not ’therapeutic’ US. Thus, ’imaging’ is implicit anywhere
the term ’ultrasound’ is used.pre-print847 K
MAP17 and SGLT1 Protein Expression Levels as Prognostic Markers for Cervical Tumor Patient Survival
MAP17 is a membrane-associated protein that is overexpressed in human tumors. Because the expression of MAP17 increases reactive oxygen species (ROS) generation through SGLT1 in cancer cells, in the present work, we investigated whether MAP17 and/or SGLT1 might be markers for the activity of treatments involving oxidative stress, such as cisplatin or radiotherapy. First, we confirmed transcriptional alterations in genes involved in the oxidative stress induced by MAP17 expression in HeLa cervical tumor cells and found that Hela cells expressing MAP17 were more sensitive to therapies that induce ROS than were parental cells. Furthermore, MAP17 increased glucose uptake through SGLT receptors. We then analyzed MAP17 and SGLT1 expression levels in cervical tumors treated with cisplatin plus radiotherapy and correlated the expression levels with patient survival. MAP17 and SGLT1 were expressed in approximately 70% and 50% of cervical tumors of different types, respectively, but they were not expressed in adenoma tumors. Furthermore, there was a significant correlation between MAP17 and SGLT1 expression levels. High levels of either MAP17 or SGLT1 correlated with improved patient survival after treatment. However, the patients with high levels of both MAP17 and SGLT1 survived through the end of this study. Therefore, the combination of high MAP17 and SGLT1 levels is a marker for good prognosis in patients with cervical tumors after cisplatin plus radiotherapy treatment. These results also suggest that the use of MAP17 and SGLT1 markers may identify patients who are likely to exhibit a better response to treatments that boost oxidative stress in other cancer types. © 2013 Perez et al.This work was supported by grants from the Spanish Ministry of Science and Innovation and FEDER funds (SAF2009-08605), Consejeria de Ciencia e Innovacion and Consejeria de Salud of the Junta de Andalucia (CTS-6844 and PI-0142) and FIS (PI12/00137). AC’s laboratory is also funded by a fellowship from the Fundacion Oncologica FERO, supported by Fundació Josep Botet.Peer Reviewe
Promoting physical activity at the school playground: A quasi-experimental intervention study
In looking for new strategies to promote physical activity (PA), the purpose of this study was to determine whether providing equipment, playground markings, and a physical education (PE)-based intervention effectively increases PA levels during school recess. A total of 223 children (mean age = 7.10 years ± 0.6; 45.3% female) from three schools participated in this study in 2012. In the first intervention school (G1; n = 75) six previous PE classes teaching games for recess were performed and playground markings and game equipment were provided. In the second intervention school (G2; n = 68) only playground markings and game equipment were provided. The third school served as the control group (GC; n = 80). PA was assessed with pedometers. The increase in mean steps after intervention in G2 was higher than the G1 and GC (P < 0.001). No differences between G1 and GC were observed at post-intervention (P = 0.05). The effects did not vary by gender or BMI. Providing game equipment and playground marks may increase children PA in recess. Nevertheless, additional PE-based intervention did not imply an improvement, and was not effective in increasing PA
Carbon burial and storage in tropical salt marshes the influence of sea level rise
Los hábitats de vegetación costera pueden ser sumideros importantes de carbono orgánico (Corg) y mitigar el calentamiento global mediante secuestrar cantidades significativas de CO2 atmosférico y almacenan Corg sedimentario durante largos períodos, aunque
su capacidad de entierro y almacenamiento en Corg puede verse afectada por el aumento continuo del nivel del mar y la intervención humana. Datos geoquímicos de núcleos de sedimentos fechados 210Pb publicados, recolectados de microtidios costeros de baja energía humedales en El Salvador (Bahía Jiquilisco) y en México (Laguna Salada; Laguna Estero de Urias; Sian Ka'an Reserva de la Biosfera) se revisaron para evaluar los cambios temporales (en los últimos 100 años) de las concentraciones de Corg, tasas de almacenamiento y enterramiento en marismas tropicales bajo la influencia del aumento y contraste del nivel del mar. Grado de antropización. La distribución del tamaño de grano se usó para identificar cambios hidrodinámicos, y δ13C para distinguir sedimentos terrígenos de los acumulados bajo la influencia de la transgresión marina. A pesar de que los rangos de tasa de acreción en todos los registros de sedimentos fueron comparables, concentraciones de Corg (0.2–30%), poblaciones entre las áreas de estudio. Sin embargo, en la mayoría de los sitios, el aumento del nivel del mar disminuyó las concentraciones de Corg y las reservas de sedimentos, pero aumentó las tasas de entierro de Corg. Las concentraciones de Corg más bajas se atribuyeron a la entrada de equipos marinos reelaborados partículas, que contribuyen con una menor cantidad de Corg que los sedimentos terrígenos; mientras que mayor entierro Corg las tasas fueron impulsadas por las altas tasas de acumulación, influenciadas por el aumento de las inundaciones y las intervenciones humanas en los alrededores. La acumulación de Corg y la conservación a largo plazo en las marismas tropicales pueden ser tan altas como en manglares o marismas templadas y, además de la reducción de las poblaciones de Corg por el aumento continuo del nivel del mar, la perturbación de los inventarios de Corg enterrados a largo plazo podría causar altas emisiones de CO2, por lo que deben ser protegidos como parte de los esfuerzos de mitigación del cambio climático
The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey
The Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic
data from the Baryon Oscillation Spectroscopic Survey (BOSS). This ninth data
release (DR9) of the SDSS project includes 535,995 new galaxy spectra (median
z=0.52), 102,100 new quasar spectra (median z=2.32), and 90,897 new stellar
spectra, along with the data presented in previous data releases. These spectra
were obtained with the new BOSS spectrograph and were taken between 2009
December and 2011 July. In addition, the stellar parameters pipeline, which
determines radial velocities, surface temperatures, surface gravities, and
metallicities of stars, has been updated and refined with improvements in
temperature estimates for stars with T_eff<5000 K and in metallicity estimates
for stars with [Fe/H]>-0.5. DR9 includes new stellar parameters for all stars
presented in DR8, including stars from SDSS-I and II, as well as those observed
as part of the SDSS-III Sloan Extension for Galactic Understanding and
Exploration-2 (SEGUE-2).
The astrometry error introduced in the DR8 imaging catalogs has been
corrected in the DR9 data products. The next data release for SDSS-III will be
in Summer 2013, which will present the first data from the Apache Point
Observatory Galactic Evolution Experiment (APOGEE) along with another year of
data from BOSS, followed by the final SDSS-III data release in December 2014.Comment: 9 figures; 2 tables. Submitted to ApJS. DR9 is available at
http://www.sdss3.org/dr
Chemical Analysis of the Brightest Star of the Cetus II Ultra-Faint Dwarf Galaxy Candidate
We present a detailed chemical abundance analysis of the brightest star in
the ultra-faint dwarf (UFD) galaxy candidate Cetus II from high-resolution
Magellan/MIKE spectra. For this star, DES J011740.53-173053, abundances or
upper limits of 18 elements from Carbon to Europium are derived. Its chemical
abundances generally follow those of other UFD galaxy stars, with a slight
enhancement of the alpha-elements (Mg, Si, and Ca) and low neutron-capture
element (Sr, Ba, Eu) abundances supporting the classification of Cetus II as a
likely UFD. The star exhibits lower Sc, Ti, and V abundances than Milky Way
(MW) halo stars with similar metallicity. This signature is consistent with
yields from a supernova (SN) originating from a star with a mass of ~11.2 solar
masses. In addition, the star has a Potassium abundance of [K/Fe] = 0.81 which
is somewhat higher than the K abundances of MW halo stars with similar
metallicity, a signature which is also present in a number of UFD galaxies. A
comparison including globular clusters (GC) and stellar stream stars suggests
that high K is a specific characteristic for some UFD galaxy stars and can thus
be used to help classify objects as UFD galaxies.Comment: 15 pages, 7 figures, 5 tables, accepted to Ap
The MADPSZ catalogue of Planck clusters over the DES region: extending to lower mass and higher redshift
We present the first systematic follow-up of Planck Sunyaev-Zeldovich effect
(SZE) selected candidates down to signal-to-noise (S/N) of 3 over the 5000
deg covered by the Dark Energy Survey. Using the MCMF cluster confirmation
algorithm, we identify optical counterparts, determine photometric redshifts
and richnesses and assign a parameter, , that reflects the
probability that each SZE-optical pairing represents a real cluster rather than
a random superposition of physically unassociated systems. The new MADPSZ
cluster catalogue consists of 1092 MCMF confirmed clusters and has a purity of
85%. We present the properties of subsamples of the MADPSZ catalogue that have
purities ranging from 90% to 97.5%, depending on the adopted
threshold. halo mass estimates, redshifts, richnesses, and optical
centers are presented for all MADPSZ clusters. The MADPSZ catalogue adds 828
previously unknown Planck identified clusters over the DES footprint and
provides redshifts for an additional 50 previously published Planck selected
clusters with S/N>4.5. Using the subsample with spectroscopic redshifts, we
demonstrate excellent cluster photo- performance with an RMS scatter in
of 0.47%. Our MCMF based analysis allows us to infer the
contamination fraction of the initial S/N>3 Planck selected candidate list,
which is 50%. We present a method of estimating the completeness of the MADPSZ
cluster sample and selected subsamples. In comparison to the
previously published Planck cluster catalogues. this new S/N 3 MCMF
confirmed cluster catalogue populates the lower mass regime at all redshifts
and includes clusters up to z1.3.Comment: 20 pages, 5 Appendices, 17 figures, submitted to MNRA
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