Duality for the Jordanian Matrix Quantum Group GLg,h(2)GL_{g,h}(2)

We find the Hopf algebra $U_{g,h}$ dual to the Jordanian matrix quantum group $GL_{g,h}(2)$. As an algebra it depends only on the sum of the two parameters and is split in two subalgebras: $U'_{g,h}$ (with three generators) and $U(Z)$ (with one generator). The subalgebra $U(Z)$ is a central Hopf subalgebra of $U_{g,h}$. The subalgebra $U'_{g,h}$ is not a Hopf subalgebra and its coalgebra structure depends on both parameters. We discuss also two one-parameter special cases: $g =h$ and $g=-h$. The subalgebra $U'_{h,h}$ is a Hopf algebra and coincides with the algebra introduced by Ohn as the dual of $SL_h(2)$. The subalgebra $U'_{-h,h}$ is isomorphic to $U(sl(2))$ as an algebra but has a nontrivial coalgebra structure and again is not a Hopf subalgebra of $U_{-h,h}$.Comment: plain TeX with harvmac, 16 pages, added Appendix implementing the ACC nonlinear ma

Removal of power-line interference from the ECG: a review of the subtraction procedure

BACKGROUND: Modern biomedical amplifiers have a very high common mode rejection ratio. Nevertheless, recordings are often contaminated by residual power-line interference. Traditional analogue and digital filters are known to suppress ECG components near to the power-line frequency. Different types of digital notch filters are widely used despite their inherent contradiction: tolerable signal distortion needs a narrow frequency band, which leads to ineffective filtering in cases of larger frequency deviation of the interference. Adaptive filtering introduces unacceptable transient response time, especially after steep and large QRS complexes. Other available techniques such as Fourier transform do not work in real time. The subtraction procedure is found to cope better with this problem. METHOD: The subtraction procedure was developed some two decades ago, and almost totally eliminates power-line interference from the ECG signal. This procedure does not affect the signal frequency components around the interfering frequency. Digital filtering is applied on linear segments of the signal to remove the interference components. These interference components are stored and further subtracted from the signal wherever non-linear segments are encountered. RESULTS: Modifications of the subtraction procedure have been used in thousands of ECG instruments and computer-aided systems. Other work has extended this procedure to almost all possible cases of sampling rate and interference frequency variation. Improved structure of the on-line procedure has worked successfully regardless of the multiplicity between the sampling rate and the interference frequency. Such flexibility is due to the use of specific filter modules. CONCLUSION: The subtraction procedure has largely proved advantageous over other methods for power-line interference cancellation in ECG signals

Duality for Exotic Bialgebras

In the classification of Hietarinta, three triangular $4\times 4$ $R$-matrices lead, via the FRT formalism, to matrix bialgebras which are not deformations of the trivial one. In this paper, we find the bialgebras which are in duality with these three exotic matrix bialgebras. We note that the $L-T$ duality of FRT is not sufficient for the construction of the bialgebras in duality. We find also the quantum planes corresponding to these bialgebras both by the Wess-Zumino R-matrix method and by Manin's method.Comment: 25 pages, LaTeX2e, using packages: cite, amsfonts, amsmath, subeq

Dissecting the long-term emission behaviour of the BL Lac object Mrk 421

We report on long-term multiwavelengthmonitoring of blazar Mrk 421 by the GLAST-AGILE Support Program of the Whole Earth Blazar Telescope (GASP-WEBT) collaboration and Steward Observatory, and by the Swift and Fermi satellites. We study the source behaviour in the period 2007–2015, characterized by several extreme flares. The ratio between the optical, X-ray and γ -ray fluxes is very variable. The γ -ray flux variations show a fair correlation with the optical ones starting from 2012.We analyse spectropolarimetric data and find wavelengthdependence of the polarization degree (P), which is compatible with the presence of the host galaxy, and no wavelength dependence of the electric vector polarization angle (EVPA). Optical polarimetry shows a lack of simple correlation between P and flux and wide rotations of the EVPA.We build broad-band spectral energy distributions with simultaneous near-infrared and optical data from the GASP-WEBT and ultraviolet and X-ray data from the Swift satellite. They show strong variability in both flux and X-ray spectral shape and suggest a shift of the synchrotron peak up to a factor of ∼50 in frequency. The interpretation of the flux and spectral variability is compatible with jet models including at least two emitting regions that can change their orientation with respect to the line of sight.http://10.0.4.69/mnras/stx2185Accepted manuscrip

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K e y w o r d s : grehlin signaling, hormone, orexigenic, prostaglaudin, smooth muscle, tromboxane Furthermore, hormones and local mediators often change the conductivity of ion channels in the cell membrane, which can be used as sensors for proper signaling. Our pilot study showed that ghrelin reduces the iberiotoxin-sensitive Ca 2+ -activated potassium current (I K(Ca) ) elicited in freshly isolated smooth muscle cells of human mesenteric arteries via PLD-and PKCdependent mechanism (15). The sarcoplasmic reticulum is also necessary for this signaling as the blockade of sarco-endoplasmic reticulum Ca 2+ ATPase or IP 3 -activated Ca 2+ channels of internal Ca 2+ stores inhibit the effect of ghrelin on I K(Ca) In the present study, we used pharmacological tools to identify the participants of ghrelin signaling and found a second mediator involved. MATERIALS AND METHODS The investigation conformed to the 'Declaration of Helsinki' 1975Helsinki' (revised 1983. Mesenteric arteries were isolated from extracted specimens of human mesentery taken during abdominal surgery on patients -63 men aged 64.6±1.5 years and 43 women aged 59.3±1.9 -and transported to the laboratory in ice-cold saline. Half of the patients were operated for malignant growths (carcinoma sigma) and the rest -for nonmalignant conditions. Contraction studies Segments of mesenteric arteries were dissected, carefully cleaned of adipose and connective tissues and kept in ice-cold low Ca 2+ solution containing (mmol): 118 NaCl, 5 KCl, 1.2 MgCl 2 , 0.16 CaCl 2 , 10 glucose, 1.2 Na 2 HPO 4 and 24 HEPES. Arterial rings (2 mm long) were mounted on a wire-myograph for isometric tension recording DMT, model 410A (Danish Myo Technology, Aarhus, Denmark) whose chamber was filled with the same ice-cold low Ca 2+ solution. After the mounting of the vessel rings, the organ bath solution was replaced with the same solution containing 2.5 mmol CaCl 2 . The bath was heated up to 37°C and continually bubbled with carbogen (95% O 2 and 5% CO 2 ). The isometric force of contraction was recorded using the program Myodaq (DMT, Aarhus, Denmark). The arterial segments were equilibrated for 1 hour at 37°C in a buffer, which was changed at least 3 times during this equilibration period. In most experiments, the endothelium was removed by careful rubbing with a rat whisker. Then vessels were stretched to their optimal lumen diameter, corresponding to 90% of the passive diameter of the vessel at 100 mm Hg. The viability of the preparations was tested twice by application of 10 µmol noradrenaline. The integrity of the endothelium was tested with 10 µmol acetylcholine added to 10 µmol noradrenaline contracted rings. After the viability tests, the strips were contracted with 1 nmol ET-1, which produced relatively stable isometric contractions allowing the study of the effect of the increasing concentrations of ghrelin. The tension reached a steady state in about 40 minutes after the application of ET-1. Then ghrelin was applied to the bath in increasing concentrations of 10, 30, 100, 300 and 1000 nmol, i.e. starting from a value that is about 10 times higher than its plasma level. It led to a significant effect on native artery preparations (with endothelium and in the absence of TTX) at a 30-100 times higher concentration than in human circulation (11). A possible explanation of this result is that ghrelin has a low diffusion rate through the adventitia, which decreases its interaction with receptors of smooth muscle cells when applied to the bath solution. Other researchers have also used higher ghrelin concentrations while studying the effect of ghrelin on vascular preparations (12), probably due to the same reason. It is also possible that ghrelin reaches such values in the smooth muscle layer of the arterial wall due to its paracrine release from human vascular endothelium (16). Additionally, guinea pigs may have a higher plasma level of ghrelin if compared to humans or rats. The ghrelin-induced changes in tension were expressed as a percentage of the maximum tension elicited by 1 nmol ET-1. The influence of different pharmacological agents (inhibitors) on ghrelin effect was studied by means of their addition to the bath about 40 min after ET-1 application and incubated for about 30 min before the application of ghrelin. The effects of inhibitors were studied using several types in vitro preparations: i) native (untreated) preparations of small human mesenteric arteries; ii) endothelium-denuded preparations; iii) native preparations with tetrodotoxin (TTX, 300 nmol) and mainly iv) endotheliumdenuded and TTX-treated preparations. The time control preparations were equally treated, but instead of ghrelin, an equal volume of solvent (deionised water) was added at the same time intervals. The inhibitors and antagonist were applied to block (to switch off) the studied enzyme or receptor activity and not to induce a partial inhibition only. This forced us to use a higher concentration of these substances. On the other hand, the possibility of a non-specific effect of the pharmacological tools restricted us to using them in lower concentrations. Thus, the aim to choose the optimal concentration of each substance for our experiments was not easy. For almost all of the blockers, however, there are at least several studies on arterial preparations in vitro, in some cases with dose-response curves and/or tests for cross-reaction. Besides, the choice of each concentration was based on our earlier experience with a significant part of the substances used either in electrophysiological or functional studies of different vascular beds. Whole-cell patch-clamp experiments This method has been described in detail elsewhere (17). In brief, whole-cell voltage-clamp experiments were performed on single smooth muscle cells, freshly isolated from human mesenteric arteries. The arteries were cut into 3 mm long pieces and placed in 0.1 mmol Ca 2+ -containing physiological salt solution (PSS, for composition see below) warmed to 37°C and containing 1.5 mg ml -1 collagenase II, 1 mg ml -1 papain, 15 µl ml -1 elastase and 1 mg ml -1 albumin. After 30 to 35 min incubation at 37°C with continuous O 2 bubbling, the enzymes were washed away and the tissue pieces triturated 5 times in Ca 2+ -free PSS using a pipette with a small tip opening. The remainder of the tissue was put back into the enzyme-containing solution for another 5 min and then carefully washed with Ca 2+ -free PSS. Single smooth muscle cells were obtained by gentle trituration in 2 ml of the same Ca 2+ -free solution. Cells could be stored for up to 8 hours in this solution at 4-6°C. The external solution (PSS) for single-cell voltage experiments contained (in mmol): 126 NaCl, 5.6 KCl, 10 HEPES, 20 taurine, 20 glucose, 1.1 MgCl 2 , 0.8 CaCl 2 , 5 Napyruvate and pH was adjusted to 7.4 with NaOH. The same solution was used for the isolation of cells. The solutions in the recording pipette contained (in mmol): 125 KCl, 6 NaCl, 10 HEPES, 1 MgCl 2 , 3 EGTA, 0.1 ATP, 5 Na-pyruvate, 5 succinate, 5 oxalacetate, 5 glucose and 2.15 CaCl 2 to give a calculated free Ca 2+ of 200 nmol and pH was adjusted to 7.4 with KOH. Chemicals Most of the substances used for solution preparation were obtained from ICN (Irvine, CA, USA). NaOH, BSA, 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate (NCDC), pertussis toxin, indomethacin, O-(octahydro-4,7-methano-1H-inden-5-yl) carbonopotassium dithioate (D-609), collagenase type II, prostaglandine F 2α (PGF 2α ), (5Z,13E) -(9S,11S,15R)-384 9,15,dihydroxy-11-fluoro-15-(2-indanyl)- Data analysis Current densities were expressed in pA/pF and plotted as functions of the potential applied to obtain data suitable for statistical analysis. The significance of differences between means was assessed using Tukey-Kramer multiple comparison test with p<0.05 regarded significant. The force of contraction was evaluated as a difference in tension (N/m) measured before ET-1 application and the plateau reached afterwards. The contractile effect of ghrelin was expressed as a percentage of the maximal ET-1 induced contraction, taken as 100%. Values were expressed as means±S.E.M. From five to ten human mesenteric arterial preparations (n) were included in the construction of each concentration-response curve of ghrelin. Data were subjected to a comparative statistical analysis one-way ANOVA with Bonferroni correction (p<0.05). RESULTS Octanoyl ghrelin, herein referred to as ghrelin, dosedependently increased the force of contraction of isometric human mesenteric artery preparations constricted with ET-1 The application of increasing doses of ghrelin to external solution containing either NCDC (50 mol) ( The application of increasing concentrations of ghrelin to TTX-and ET-1-containing bath solution failed to influence significantly the force of contraction of endothelium-denuded human mesenteric arteries in the presence of PP2 (10 µmol) -a selective Src family kinase inhibitor The addition of ghrelin (100 nmol) almost entirely inhibited the iberiotoxin-sensitive I K(Ca) recorded during a 500 ms depolarizing pulse to +40 mV from a holding potential of -50 mV (12). Rp-cAMPS (200 µmol), a specific membranepermeable inhibitor of PKA, was without effect on the total outward potassium current (I K ) (n=5), while the subsequent addition of ghrelin (100 nmol) decreased I K to the same degree as in the absence of this PKA inhibitor in single smooth muscle cells from human mesenteric arteries (n=5; p<0.01) DISCUSSION Ghrelin and des-octanoyl ghrelin are equipotent antagonists of ET-1 induced vasoconstriction of human mammary artery (13) while in single smooth muscle cells isolated from human mesenteric arteries des-octanoyl ghrelin blocks the ghrelininduced inhibition of I K(Ca) . This difference supposes the operation of more than one ghrelin receptors in human vascular beds -the des-octanoyl ghrelin-blockable GHS-R1a in human mesenteric arteries and another type in human mammary artery (for a review of ghrelin receptors see 19). Kleinz et al. (13) routinely applied indomethacin to exclude the possibility of endothelium dependent vasodilatation. This treatment however blocks not only endothelial COX1/2 but also those in the tunica media of the artery and thus eliminates the influence of COX1/2 downstream products generated in smooth muscle cells, as suggested by our study. Indeed, such a mechanism is unexpected in blood vessels but is reported in non-vascular smooth muscle (lower esophageal sphincter) that maintains mainly tonic type of contraction similarly to arteries (20). Therefore, it is still difficult to summarize the mechanisms of ghrelin effects on human arteries due to their opposite influences -relaxation and contraction, the different experimental conditions applied and the need for more detailed studies of the intracellular participants. Most often GHS-R1a interacts with heterotrimeric G q/11 proteins and stimulates the G q/11 /PI-PLC/IP 3 +Ca 2+ +DAG/PKC signaling (2). It was reported that the application of a specific PKC inhibitor entirely abolished the effect of ghrelin on I K(Ca) , recorded in single smooth muscle cells of human mesenteric arteries (15). In our study the force of contraction of human mesenteric arteries did not respond to ghrelin application if iberiotoxin or GF109203x were present in the bath solution. Thus, ghrelin requires activation of PKC and suppresses K Ca channels with a large conductance (BK Ca channels) to increase the force of contraction. Ghrelin regulates cAMP/PKA (3-5) and cGMP/PKG signaling (6), which can further influence ion channels. Han et al. (6) reported a ghrelin-induced reduction of voltage-gated I K of rat anterior pituitary tumor (GH3) cells by a PKG-dependent mechanism and Kohno et al. (21) -a ghrelin-induced activation of N-type Ca 2+ channels that required PKA. BK Ca channels are involved in the formation of the spontaneous artery tone, counteract the elevation of the agonist-induced cytosolic free Ca 2+ and participate in the relaxation induced by cAMP/PKAand cGMP/PKG-coupled agonists (22). Therefore, we investigated the participation of both cyclic nucleotides using specific inhibitors Rp-cAMPS for PKA and ODQ for soluble guanylate cyclase. The presence of inhibitors of PKA or soluble guanylate cyclase in the bath solution did not prevent the effect of ghrelin on I K(Ca) . We concluded that the second messengers cAMP and cGMP are not involved in the observed ghrelininduced inhibition of I K(Ca) . On the other hand, in human mesenteric arteries the effect of ghrelin on the force of contraction is blocked by pertussis toxin, which suggests the participation of G i -proteins. In rat islet β-cells ghrelin decreases the insulin secretion by a G αi2 -protein sensitive activation of voltage-gated K + channels and this effect is blocked by D-Lys 3 -GHRP-6, a specific GHS-R1a inhibitor (23). Ghrelin inhibits BK Ca channels in the guinea pig femoral artery via a pertussis toxin and GHS-R1a sensitive pathway (17). Ghrelin also activates G i -protein in cell cultures Ca 2+ released from sarcoplasmic reticulum activates BK Ca channels of smooth muscles cells (24). In human mesenteric arteries IP 3 -sensitive Ca 2+ release is essential for the ghrelininduced decrease of I K(Ca) (15) and for the increase of the force of contraction. Additionally, IP 3 -induced Ca 2+ release from sarcoplasmic reticulum participates in the ET-1 evoked contraction of this vascular bed. Our pharmacological studies suggest that several DAG-producing phospholipases (PI-PLC and PC-PLC) are important in establishing the effect of ghrelin in human mesenteric arteries. We presume that PI-PLC is essential mainly for triggering the contraction (25) and for the IP 3 -induced Ca 2+ release-dependent translocation of PKC to the plasma membrane, while the sustained DAG producer PC-PLC (25) is responsible for the long lasting PKC activation. This suggestion is indirectly supported by the slowly developing inhibition (in 10-14 min) of I K(Ca) by ghrelin in this tissue (15). Using different inhibitors we reveal several new enzymes participating in the ghrelin effect in human mesenteric arteries. Thus, the selective inhibition of MEK or Src kinase entirely blocks the ghrelin-induced contractions in endothelium-denuded human mesenteric arteries with suppressed neurotransmission. The nonselective COX1/2 inhibitor indomethacin eliminates either the ghrelin-induced constriction of human mesenteric arteries or the ghrelin-induced decrease of I K in single smooth muscle cells isolated from the same tissue. All these data suggest the existence of a ghrelin-induced and pertussis toxin-sensitive mechanism, which increases the force of contraction by a consequent activation of Src kinase, MEK and ERK. Similar G iprotein initiated signaling was reported for non-vascular tissues (for review see 26). Next, the stimulated ERK may activate the cytosolic PLA 2 (27), which increases vascular arachidonic acid production -the rate-limiting step for prostaglandin synthesis (28). COX1/2 transform this arachidonic acid into PGE 2 , and then PGE 2 into PGH 2 , which may further yield contracting prostaglandin or thromboxane, as reported for non-vascular smooth muscle It was reported that ghrelin receptor type GHR-R1a has the ability to oligomerize with prostanoid receptors, when they are transiently over-expressed in human embryonic kidney 293 cells (32). The same authors stated that this co-transfection significantly influenced GHR-R1a activity without changes in its affinity for ghrelin. Similarly, as an alternative explanation of our data, it is suggested that ghrelin first binds to GHS-R1a and then activates prostanoid receptor via a direct interaction in the existing GHS-R1a/prostanoid receptor heteromeric complex. If this is the case, the enzymes necessary to demonstrate the effect of ghrelin on the contractile activity (Src kinase, MEK, COX-1 and thromboxane synthase) only support the steady-state thromboxane A 2 production and are not additionally activated by ghrelin. The second explanation of our data, however, seems to be less probable as several new articles report a direct activation of ERK1/2 (3, 7, 33) and Src kinase (34) by ghrelin signaling. Ghrelin decreases the mean arterial pressure of the rat by a COX-insensitive and NOS-sensitive mechanism (35). In rat mesenteric arteries both ghrelin and desacyl ghrelin evoke endothelium-dependent dilation by NOS-and COX-insensitive mechanism (36). Ghrelin inhibits the contraction of human aortic smooth muscle cells by cAMP/PKA pathway activation (4). Ghrelin and desacyl ghrelin antagonize the ET-1-induced contraction of human internal mammary artery (13). Ghrelin decreases the mean arterial pressure in humans as well (11). On the other hand, contractile effects of ghrelin were reported in guinea pig femoral (37) and renal (17) arteries and in rat coronary artery (38). Ghrelin increases the force of contraction of human mesenteric arteries partially constricted with ET-1. The effect is stronger in endothelium-denuded preparations and most pronounced in endothelium-denuded artery segments with blocked action potential propagation of perivascular neurons. These data point to a relaxing effect of ghrelin via endothelium and axonal projections in adventitia, which antagonize the direct and stronger contractile action of ghrelin on the smooth muscle layer of the vascular wall. Additionally, if compared to native preparations during the first half of the experiments, the higher force of contractions of endothelium-denuded human mesenteric arteries suggest that endothelium, as well as perivascular neurotransmission are functional, i.e. they are not badly damaged by the therapy before the surgical intervention or during the transportation. It can be concluded that ghrelin either increases or decreases the force of contraction of arteries depending on their type and the species. Thus, ghrelin and desacyl ghrelin may influence the artery resistance similarly to other regulators of the circulation with opposite effects on different vascular beds. For example, catecholamines redistribute the blood flow throughout the body, depending on the physiological needs, via different adrenergic receptors and intracellular mechanisms. In summary, ghrelin has been shown to increase the force of contraction of human mesenteric arteries by a novel mechanism that requires active Src kinase, MEK, COX-1 and thromboxane synthase and that depends on the release of a local mediator -a T prostanoid receptor agonist. Additionally, our data suggest a novel physiological regulation, in which an empty stomachinitiated increase of ghrelin secretion reduces the abdominal circulation in adult humans until next meal. Acknowledgement

A new activity phase of the blazar 3C 454.3. Multifrequency observations by the WEBT and XMM-Newton in 2007-2008

We present and analyse the WEBT multifrequency observations of 3C 454.3 in the 2007-2008 observing season, including XMM-Newton observations and near-IR spectroscopic monitoring, and compare the recent emission behaviour with the past one. In the optical band we observed a multi-peak outburst in July-August 2007, and other faster events in November 2007 - February 2008. During these outburst phases, several episodes of intranight variability were detected. A mm outburst was observed starting from mid 2007, whose rising phase was contemporaneous to the optical brightening. A slower flux increase also affected the higher radio frequencies, the flux enhancement disappearing below 8 GHz. The analysis of the optical-radio correlation and time delays, as well as the behaviour of the mm light curve, confirm our previous predictions, suggesting that changes in the jet orientation likely occurred in the last few years. The historical multiwavelength behaviour indicates that a significant variation in the viewing angle may have happened around year 2000. Colour analysis reveals a complex spectral behaviour, which is due to the interplay of different emission components. All the near-IR spectra show a prominent Halpha emission line, whose flux appears nearly constant. The analysis of the XMM-Newton data indicates a correlation between the UV excess and the soft-X-ray excess, which may represent the head and the tail of the big blue bump, respectively. The X-ray flux correlates with the optical flux, suggesting that in the inverse-Compton process either the seed photons are synchrotron photons at IR-optical frequencies or the relativistic electrons are those that produce the optical synchrotron emission. The X-ray radiation would thus be produced in the jet region from where the IR-optical emission comes.Comment: 10 pages, 12 figures (7 included in the text, 5 in GIF format), accepted for publication in A&

Childhood predictors of adolescent behaviour: The prospective association of familial factors with meeting physical activity guidelines

Little is known about the longitudinal association of familial socio-demographic factors, behaviours, attitudes, or home environment with meeting physical activity guidelines. Our objective was to a) describe 4-year change in the prevalence of meeting guidelines, and characteristics of participants across categories of physical activity maintenance, and b) identify familial factors in childhood that are longitudinally associated with meeting guidelines in adolescence. Data on 17 parent- and child-reported family variables and objectively measured physical activity (ActiGraph GT1M) were available from 406 children (10.3 ± 0.3 years, 53.5% female) participating in the SPEEDY study. Average duration of week- and weekend day moderate-to-vigorous physical activity (MVPA, ≥ 2000 cpm) at baseline and follow-up (14.3 ± 0.3 years) were calculated to determine whether participants met 60 min MVPA/day guidelines at each assessment. Descriptives were calculated across four MVPA change categories. Multi-level logistic regression examined the association of baseline familial factors with meeting guidelines at follow-up, adjusting for sex, baseline physical activity, family socio-economic position, and school clustering. At follow-up, 51.5% and 36.1% of adolescents met guidelines on weekdays and weekend days, respectively (baseline: 68.0%, 67.2%). Girls were less likely than boys to remain sufficiently active, particularly on weekdays. Family social support was positively associated with adolescents meeting guidelines at weekends (OR 1.2; 95% CI 1.0-1.4). The presence of play equipment at home was negatively associated with meeting guidelines on weekdays (OR 0.5; 95% CI 0.3-0.8). Interventions that foster parent's facilitation of physical activity may help to encourage the upkeep of healthy behaviours during the transition from childhood to adolescence.The SPEEDY study is funded by the National Prevention Research Initiative (G0501294) (http://www.npri.org.uk), consisting of the following Funding Partners: British Heart Foundation; Cancer Research UK; Department of Health; Diabetes UK; Economic and Social Research Council; Medical Research Council; Health and Social Care Research and Development Office for the Northern Ireland; Chief Scientist Office, Scottish Government Health Directorates; Welsh Assembly Government and World Cancer Research Fund. The work was also undertaken under the auspices of the Centre for Diet and Activity Research (CEDAR), a UKCRC Public Health Research Centre of Excellence which is funded by the British Heart Foundation, Cancer Research UK, Economic and Social Research Council, Medical Research Council, the National Institute for Health Research, and the Wellcome Trust. Kirsten Corder reports receiving the following grants: Lead Applicant - A cluster randomised controlled trial to evaluate the effectiveness and cost-effectiveness of the GoActive programme to increase physical activity among 13–14 year-old adolescents. Project: 13/90/18 National Institute for Health Research Public Health Research Programme Sept 2015 – Feb 2019. Co-Applicant - Opportunities within the school environment to shift the distribution of activity intensity in adolescents. Department of Health Policy Research Programme. Dec 2013 – Nov 2016. Kirsten Corder is a Director of Ridgepoint Consulting Limited, an operational improvement consultancy

WEBT multiwavelength monitoring and XMM-Newton observations of BL Lacertae in 2007-2008. Unveiling different emission components

In 2007-2008 we carried out a new multiwavelength campaign of the Whole Earth Blazar Telescope (WEBT) on BL Lacertae, involving three pointings by the XMM-Newton satellite, to study its emission properties. The source was monitored in the optical-to-radio bands by 37 telescopes. The brightness level was relatively low. Some episodes of very fast variability were detected in the optical bands. The X-ray spectra are well fitted by a power law with photon index of about 2 and photoelectric absorption exceeding the Galactic value. However, when taking into account the presence of a molecular cloud on the line of sight, the data are best fitted by a double power law, implying a concave X-ray spectrum. The spectral energy distributions (SEDs) built with simultaneous radio-to-X-ray data at the epochs of the XMM-Newton observations suggest that the peak of the synchrotron emission lies in the near-IR band, and show a prominent UV excess, besides a slight soft-X-ray excess. A comparison with the SEDs corresponding to previous observations with X-ray satellites shows that the X-ray spectrum is extremely variable. We ascribe the UV excess to thermal emission from the accretion disc, and the other broad-band spectral features to the presence of two synchrotron components, with their related SSC emission. We fit the thermal emission with a black body law and the non-thermal components by means of a helical jet model. The fit indicates a disc temperature greater than 20000 K and a luminosity greater than 6 x 10^44 erg/s.Comment: 11 pages, 7 figures, accepted for publication in A&