Single-Leg Resistance Exercise Training in Mice Leads to a Fast Increase in In Vivo Torque of Anterior Crural Muscles

Resistance exercise is known to produce muscle hypertrophy. However, little is known about the role of muscle satellite cells in generating new myofibers or in incorporating satellite cells to live myofibers during exercise training. PURPOSE: To investigate whether single-leg resistance exercise training can activate the incorporation of muscle satellite cells in mice. METHODS: Transgenic male mice (12 weeks old) that express Td-Tomato fluorescent protein in Pax7+ (i.e., satellite cells) cells (Pax7CreER-Ai9) were treated with tamoxifen (2 mg in corn oil, i.p.) once a day for 5 days. Three days later, mice were single-leg exercise trained (i.e stimulation of the peroneal nerve of the right leg of each mouse to evoke fused tetanic contractions [100 Hz] of the anterior crural muscles), 3x per week for either 1 or 2 weeks. Each training session was composed of 3-s contractions with 7 s recovery between contractions, 10 contractions each set, 5 sets with 5 min rest between sets. Before the first training session and 3 days after the last training session (1 week or 2 weeks training), torque produced by the ankle was measured at different frequencies of pulse-stimulation (1-200 Hz), mice were euthanized, and muscles were frozen for histological measurements. RESULTS: During each session of training, peak torque developed at the last contraction was ~30% of the torque developed in the initial contraction of the session suggesting fatigue development. Between sessions of training, initial torque was not significantly different suggesting that muscle recovered function between sessions. Torque measurements at different frequencies of stimulation 3 days after 1 week or 2 weeks of training showed a ~50% increase in maximal tetanic torque relative to the mice body weight, after 1 week of training but there were no additional changes at 2 weeks of training. Tibialis anterior muscle cross sectional area and number of Td-tomato positive myofibers were also measured in these mice. CONCLUSION: Resistance exercise training in mice by using single-leg electrical stimulations leads to a fast (i.e., 1 week) increase in muscle force development

How do cities approach policy innovation and policy learning? A study of 30 policies in Northern Europe and North America

This paper reports on a study of current practice in policy transfer, and ways in which its effectiveness can be increased. A literature review identifies important factors in examining the transfer of policies. Results of interviews in eleven cities in Northern Europe and North America investigate these factors further. The principal motivations for policy transfer were strategic need and curiosity. Local officials and politicians dominated the process of initiating policy transfer, and local officials were also the leading players in transferring experience. A range of information sources are used in the search process but human interaction was the most important source of learning for two main reasons. First, there is too much information available through the Internet and the search techniques are not seen to be wholly effective in identifying the necessary information. Secondly, the information available on websites, portals and even good practice guides is not seen to be of mixed quality with risks of focussing only on successful implementation and therefore subject to some bias. Officials therefore rely on their trusted networks of peers for lessons as here they can access the ‘real implementation’ story and the unwritten lessons. Organisations which have a culture that is supportive of learning from elsewhere had strong and broad networks of external contacts and resourced their development whilst others are more insular or inward looking and reluctant to invest in policy lessons from elsewhere. Solutions to the problems identified in the evidence base are proposed

Low Q^2 Jet Production at HERA and Virtual Photon Structure

The transition between photoproduction and deep-inelastic scattering is investigated in jet production at the HERA ep collider, using data collected by the H1 experiment. Measurements of the differential inclusive jet cross-sections dsigep/dEt* and dsigmep/deta*, where Et* and eta* are the transverse energy and the pseudorapidity of the jets in the virtual photon-proton centre of mass frame, are presented for 0 < Q2 < 49 GeV2 and 0.3 < y < 0.6. The interpretation of the results in terms of the structure of the virtual photon is discussed. The data are best described by QCD calculations which include a partonic structure of the virtual photon that evolves with Q2.Comment: 20 pages, 5 Figure

Hadron Production in Diffractive Deep-Inelastic Scattering

Characteristics of hadron production in diffractive deep-inelastic positron-proton scattering are studied using data collected in 1994 by the H1 experiment at HERA. The following distributions are measured in the centre-of-mass frame of the photon dissociation system: the hadronic energy flow, the Feynman-x (x_F) variable for charged particles, the squared transverse momentum of charged particles (p_T^{*2}), and the mean p_T^{*2} as a function of x_F. These distributions are compared with results in the gamma^* p centre-of-mass frame from inclusive deep-inelastic scattering in the fixed-target experiment EMC, and also with the predictions of several Monte Carlo calculations. The data are consistent with a picture in which the partonic structure of the diffractive exchange is dominated at low Q^2 by hard gluons.Comment: 16 pages, 6 figures, submitted to Phys. Lett.

Measurement of D* Meson Cross Sections at HERA and Determination of the Gluon Density in the Proton using NLO QCD

With the H1 detector at the ep collider HERA, D* meson production cross sections have been measured in deep inelastic scattering with four-momentum transfers Q^2>2 GeV2 and in photoproduction at energies around W(gamma p)~ 88 GeV and 194 GeV. Next-to-Leading Order QCD calculations are found to describe the differential cross sections within theoretical and experimental uncertainties. Using these calculations, the NLO gluon momentum distribution in the proton, x_g g(x_g), has been extracted in the momentum fraction range 7.5x10^{-4}< x_g <4x10^{-2} at average scales mu^2 =25 to 50 GeV2. The gluon momentum fraction x_g has been obtained from the measured kinematics of the scattered electron and the D* meson in the final state. The results compare well with the gluon distribution obtained from the analysis of scaling violations of the proton structure function F_2.Comment: 27 pages, 9 figures, 2 tables, submitted to Nucl. Phys.

Measurement of Leading Proton and Neutron Production in Deep Inelastic Scattering at HERA

Deep--inelastic scattering events with a leading baryon have been detected by the H1 experiment at HERA using a forward proton spectrometer and a forward neutron calorimeter. Semi--inclusive cross sections have been measured in the kinematic region 2 <= Q^2 <= 50 GeV^2, 6.10^-5 <= x <= 6.10^-3 and baryon p_T <= MeV, for events with a final state proton with energy 580 <= E' <= 740 GeV, or a neutron with energy E' >= 160 GeV. The measurements are used to test production models and factorization hypotheses. A Regge model of leading baryon production which consists of pion, pomeron and secondary reggeon exchanges gives an acceptable description of both semi-inclusive cross sections in the region 0.7 <= E'/E_p <= 0.9, where E_p is the proton beam energy. The leading neutron data are used to estimate for the first time the structure function of the pion at small Bjorken--x.Comment: 30 pages, 9 figures, 2 tables, submitted to Eur. Phys.

Proton irradiation of CVD diamond detectors for high-luminosity experiments at the LHC

CVD diamond shows promising properties for use as a position sensitive detector for experiments in the highest radiation areas at the Large Hadron Collider. In order to study the radiation hardn ess of diamond we exposed CVD diamond detector samples to 24~GeV/$c$ and 500~MeV protons up to a fluence of $5\times 10^{15}~p/{\rm cm^2}$. We measured the charge collection distance, the ave rage distance electron hole pairs move apart in an external electric field, and leakage currents before, during, and after irradiation. The charge collection distance remains unchanged up to $1\ times 10^{15}~p/{\rm cm^2}$ and decreases by $\approx$40~\% at $5\times 10^{15}~p/{\rm cm^2}$. Leakage currents of diamond samples were below 1~pA before and after irradiation. The particle indu ced currents during irradiation correlate well with the proton flux. In contrast to diamond, a silicon diode, which was irradiated for comparison, shows the known large increase in leakage curren t. We conclude that CVD diamond detectors are radiation hard to 24~GeV/$c$ and 500~MeV protons up to at least $1\times 10^{15}~p/{\rm cm^2}$ without signal loss

Search for exotic physics in double-β decays with GERDA Phase II

A search for Beyond the Standard Model double-$\beta$ decay modes of$^{76}$Ge has been performed with data collected during the Phase II of theGERmanium Detector Array (GERDA) experiment, located at Laboratori Nazionalidel Gran Sasso of INFN (Italy). Improved limits on the decays involvingMajorons have been obtained, compared to previous experiments with $^{76}$Ge,with half-life values on the order of 10$^{23}$ yr. For the first time with$^{76}$Ge, limits on Lorentz invariance violation effects in double-$\beta$decay have been obtained. The isotropic coefficient$\mathring{a}_\text{of}^{(3)}$, which embeds Lorentz violation indouble-$\beta$ decay, has been constrained at the order of $10^{-6}$ GeV. Wealso set the first experimental limits on the search for light exotic fermionsin double-$\beta$ decay, including sterile neutrinos.<br

The SPTPoL extended cluster survey

We describe the observations and resultant galaxy cluster catalog from the 2770 deg2 SPTpol Extended Cluster Survey (SPT-ECS). Clusters are identified via the Sunyaev-Zel'dovich (SZ) effect and confirmed with a combination of archival and targeted follow-up data, making particular use of data from the Dark Energy Survey (DES). With incomplete follow-up we have confirmed as clusters 244 of 266 candidates at a detection significance ξ ≥ 5 and an additional 204 systems at 4 4 threshold, and 10% of their measured SZ flux. We associate SZ-selected clusters, from both SPT-ECS and the SPT-SZ survey, with clusters from the DES redMaPPer sample, and we find an offset distribution between the SZ center and central galaxy in general agreement with previous work, though with a larger fraction of clusters with significant offsets. Adopting a fixed Planck-like cosmology, we measure the optical richness-SZ mass (l - M) relation and find it to be 28% shallower than that from a weak-lensing analysis of the DES data-a difference significant at the 4σ level-with the relations intersecting at λ = 60. The SPT-ECS cluster sample will be particularly useful for studying the evolution of massive clusters and, in combination with DES lensing observations and the SPT-SZ cluster sample, will be an important component of future cosmological analyses