An early warning indicator for atmospheric blocking events using transfer operators

The existence of persistent midlatitude atmospheric flow regimes with time-scales larger than 5-10 days and indications of preferred transitions between them motivates to develop early warning indicators for such regime transitions. In this paper, we use a hemispheric barotropic model together with estimates of transfer operators on a reduced phase space to develop an early warning indicator of the zonal to blocked flow transition in this model. It is shown that, the spectrum of the transfer operators can be used to study the slow dynamics of the flow as well as the non-Markovian character of the reduction. The slowest motions are thereby found to have time scales of three to six weeks and to be associated with meta-stable regimes (and their transitions) which can be detected as almost-invariant sets of the transfer operator. From the energy budget of the model, we are able to explain the meta-stability of the regimes and the existence of preferred transition paths. Even though the model is highly simplified, the skill of the early warning indicator is promising, suggesting that the transfer operator approach can be used in parallel to an operational deterministic model for stochastic prediction or to assess forecast uncertainty

K_l3 form factor with two-flavors of dynamical domain-wall quarks

We report on our calculation of K \to \pi vector form factor by numerical simulations of two-flavor QCD on a 16^3x32x12 lattice at a \simeq 0.12 fm using domain-wall quarks and DBW2 glue. Our preliminary result at a single sea quark mass correponding to m_PS/m_V \simeq 0.53 shows a good agreement with previous estimate in quenched QCD and that from a phenomenological model.Comment: 6 pages, 5 figures, poster presented at Lattice2005 (Weak matrix elements); v2: a reference adde

Sunyaev-Zel'dovich Effects from Quasars in Galaxies and Groups

The energy fed by active galactic nuclei to the surrounding diffuse baryons changes their amount, temperature, and distribution; so in groups and in member galaxies it affects the X-ray luminosity and also the Sunyaev-Zel'dovich effect. Here we compute how the latter is enhanced by the transient blastwave driven by an active quasar, and is depressed when the equilibrium is recovered with a depleted density. We constrain such depressions and enhancements with the masses of relic black holes in galaxies and the X-ray luminosities in groups. We discuss how all these linked observables can tell the quasar contribution to the thermal history of the baryons pervading galaxies and groups.Comment: 4 pages, 3 figures, uses REVTeX4 and emulateapj.cls. Accepted by ApJ

Simulating Impacts of Extreme Weather Events on Urban Transport Infrastructure in the UK

Urban areas face many risks from future climate change and their infrastructure will be placed under more pressure due to changes in climate extremes. Using the Tyndall Centre Urban Integrated Assessment Framework, this paper describes a methodology used to assess the impacts of future climate extremes on transport infrastructure in London. Utilising high-resolution projections for future climate in the UK, alongside stochastic weather generators for downscaling, urban temperature and flooding models are used to provide information on the likelihood of future extremes. These are then coupled with spatial network models of urban transport infrastructure and, using thresholds to define the point at which systems cease to function normally, disruption to the networks can be simulated. Results are shown for both extreme heat and urban surface water flooding events and the impacts on the travelling population, in terms of both disruption time and monetary cost

Twisted semilocal strings in the MSSM

The standard electroweak model is extended by means of a second Brout-Englert-Higgs-doublet. The symmetry breaking potential is chosen is such a way that (i) the Lagrangian possesses a custodial symmetry, (ii) a stationary, axially symmetric ansatz of the bosonic fields consistently reduces the Euler-Lagrange equations to a set of differential equations. The potential involves, in particular, a direct interaction between the two doublets. Stationary, axially-symmetric solutions of the classical equations are constructed. Some of them can be assimilated to embedded Nielsen-Olesen strings. From these solutions there are bifurcations and new solutions appear which exhibit the characteristics of the recently constructed twisted semilocal strings. A special emphasis is set on "doubly-twisted" solutions for which the two doublets present different time-dependent phase factors. They are regular and have a finite energy which can be lower than the energy of the embedded twisted solution. Electric-type solutions, such that the fields oscillate asymptotically far from the symmetry-axis, are also reported.Comment: 17 pages, 11 figures, discussion extended, new solutions obtaine

Evidence to inform education, training and supportive work environments for midwives involved in the care of women with female genital mutilation

Female genital mutilation (FGM) is a practice that is carried out on young girls and women in 29 countries in Africa and the Middle East, as well as some Asian countries (WHO, 2008). Migration from these countries to Australia has led to an increasing number of midwives caring for women with FGM and educating families in order to prevent this harmful and illegal practice. However very little is known about the challenges midwives face in delivering care and education and what professional development and workplace strategies might better support midwives. This presentation reports on a synthesis of the peer reviewed literature published between 2004 and 2014 undertaken to identify the knowledge, experiences and needs of midwives globally with respect to FGM. This review forms part of a larger research project funded by the Department of Health and Aging to examine the obstetric outcomes of women who have FGM and midwives experiences in Australia. Ten papers were included in the review, two from lower-middle income counties and eight from high income countries. The findings indicate that midwives lack technical knowledge and cultural competency to adequately care for women. Midwives, particularly those in lower-middle income counties where FGM was traditionally practiced were found to face significant challenges in their efforts to advocate for the abandonment of the practice. Training for midwives in the area of FGM was limited. Only one study reported the outcomes of an education initiative that was found to be beneficial. Professional education and training, a working environment supported by guidelines and responsive policy and community education, were suggested are necessary to enable midwives to improve the care of women with FGM and advocate against the practice. Implications for midwifery in NSW include the need for specialised education and training for midwives on FGM, alongside opportunities for collaborative practice in contexts that support the effective reporting of FGM to authorities. Our research project will seek to further examine the implications of this review through a nation-wide survey of Australian midwives and focus group discussions with midwives in selected hospital s in NSW

Sphaleron-Bisphaleron bifurcations in a custodial-symmetric two-doublets model

The standard electroweak model is extended by means of a second Brout-Englert-Higgs-doublet. The symmetry breaking potential is chosen is such a way that (i) the Lagrangian possesses a custodial symmetry, (ii) a static, spherically symmetric ansatz of the bosonic fields consistently reduces the Euler-Lagrange equations to a set of differential equations. The potential involves, in particular, products of fields of the two doublets, with a coupling constant $\lambda_3$.Static, finite energy solutions of the classical equations are constructed. The regular, non-trivial solutions having the lowest classical energy can be of two types: sphaleron or bisphaleron, according to the coupling constants. A special emphasis is put to the bifurcation between these two types of solutions which is analyzed in function of the different constants of the model,namely of $\lambda_3$.Comment: 10 pages, 3 figure

Scalar meson in dynamical and partially quenched two-flavor QCD: lattice results and chiral loops

This is an exploratory study of the lightest non-singlet scalar $q\bar q$ state on the lattice with two dynamical quarks. Domain Wall fermions are used for both sea and valence quarks on a 16^3*32 lattice with an inverse lattice spacing of 1.7 GeV. We extract the scalar meson mass 1.58(34) GeV from the exponential time-dependence of the dynamical correlators with $m_{val}=m_{sea}$ and N_f=2. Since this statistical error-bar from dynamical correlators is rather large, we analyze also the partially quenched lattice correlators with $m_{val}$ not equal $m_{sea}$. They are positive for $m_{val}>=m_{sea}$ and negative for $m_{val}<m_{sea}$. In order to understand this striking effect of partial quenching, we derive the scalar correlator within the Partially Quenched ChPT and find it describes lattice correlators well. The leading unphysical contribution in Partially Quenched ChPT comes from the exchange of the two pseudoscalar fields and is also positive for $m_{val}>=m_{sea}$ and negative for $m_{val}<m_{sea}$ at large t. After the subtraction of this unphysical contribution from the partially quenched lattice correlators, the correlators are positive and exponentially falling. The resulting scalar meson mass 1.51(19) GeV from the partially quenched correlators is consistent with the dynamical result and has appreciably smaller error-bar.Comment: 23 pages, 8 figure

QCD Corrections to Production of Higgs Pseudoscalars

Models of electroweak symmetry breaking with more than a single doublet of Higgs scalars contain a neutral pseudoscalar boson. The production of such a pseudoscalar in hadron collisions proceeds primarily via gluon fusion through a top-quark loop (except for those models in which the pseudoscalar coupling to bottom quarks is strongly enhanced). We compute the QCD corrections to this process in the heavy-quark limit, using an effective Lagrangian derived from the axial anomaly.Comment: 9 pages, (BNL number added, 1 typo corrected, PHYZZX format, 4 figures not included, available on request), BNL-4906