Monopole Percolation in the Compact Abelian Higgs Model

We have studied the monopole-percolation phenomenon in the four dimensional Abelian theory that contains compact U(1) gauge fields coupled to unitary norm Higgs fields. We have determined the location of the percolation transition line in the plane $(\beta_g, \beta_H)$. This line overlaps the confined-Coulomb and the confined-Higgs phase transition lines, originated by a monopole-condensation mechanism, but continues away from the end-point where this phase transition line stops. In addition, we have determined the critical exponents of the monopole percolation transition away from the phase transition lines. We have performed the finite size scaling in terms of the monopole density instead of the coupling, because the density seems to be the natural parameter when dealing with percolation phenomena.Comment: 13 pages. REVTeX. 16 figs. included using eps

Importance of linking inertia and frequency response procurement: the Great Britain case

In order to decarbonise the electricity sector, the future Great Britain (GB) power system will be largely dominated by non-synchronous renewables. This will cause low levels of inertia, a key parameter that could lead to frequency deterioration. Therefore, the requirement for ancillary services that contain frequency deviations will increase significantly, particularly given the increase in size of the largest possible loss with the commissioning of large nuclear plants in the near future. In this paper, an inertia-dependent Stochastic Unit Commitment (SUC) model is used to illustrate the benefits of linking inertia and frequency response provision in low-inertia systems. We demonstrate that the cost of procuring ancillary services in GB could increase by 165% if the level of inertia is not explicitly considered when procuring frequency response. These results highlight the need to re-think the structure of ancillary-services markets, which in GB are nowadays held one month ahead of delivery

Light levitated geostationary cylindrical orbits are feasible

This paper discusses a new family of non-Keplerian orbits for solar sail spacecraft displaced above or below the Earth's equatorial plane. The work aims to prove the assertion in the literature that displaced geostationary orbits exist, possibly to increase the number of available slots for geostationary communications satellites. The existence of displaced non-Keplerian periodic orbits is ¯rst shown analytically by linearization of the solar sail dynamics around a geostationary point. The full displaced periodic solution of the non-linear equations of motion is then obtained using a Hermite-Simpson collocation method with inequality path constraints. The initial guess to the collocation method is given by the linearized solution and the inequality path constraints are enforced as a box around the linearized solution. The linear and nonlinear displaced periodic orbits are also obtained for the worst-case Sun-sail orientation at the solstices. Near-term and high-performance sails can be displaced between 10 km and 25 km above the Earth's equatorial plane during the summer solstice, while a perforated sail can be displaced above the usual station-keeping box (75 £ 75 km) of nominal geostationary satellites. Light-levitated orbit applications to Space Solar Power are also considered

Cold atoms in non-Abelian gauge potentials: From the Hofstadter "moth" to lattice gauge theory

We demonstrate how to create artificial external non-Abelian gauge potentials acting on cold atoms in optical lattices. The method employs $n$ internal states of atoms and laser assisted state sensitive tunneling. Thus, dynamics are communicated by unitary $n\times n$-matrices. By experimental control of the tunneling parameters, the system can be made truly non-Abelian. We show that single particle dynamics in the case of intense U(2) vector potentials lead to a generalized Hofstadter butterfly spectrum which shows a complex ``moth''-like structure. We discuss the possibility to employ non-Abelian interferometry (Aharonov-Bohm effect) and address methods to realize matter dynamics in specific classes of lattice gauge fields.Comment: 5 pages, 3 figure

Intersection of Place, Working Parents and Food Assistance: Implications for Preventing Child and Adolescent Obesity

Background/Purpose: The cumulative effects of the environment, educational system, and social injustices contribute to child health disparities. Collectively, these factors create barriers to national efforts aimed at reducing childhood obesity. Thus, behavioral, social, and cultural contributing factors were examined. Methods: Parents and guardians of Texas (n=714) children were interviewed by telephone using the National Survey of Children’s Health (NSCH). Weight status and variables of interest were analyzed using logistic regression. Results: Based on parental response, Hispanic children were more likely to be overweight/obese (p =0.002). Child recipients of food stamps had higher obesity rates (p- =0.011). Parents with less than a high school education had significantly more overweight/obese children (50% and 56% respectively, p <0.001). Children who did not have at least one parent employed were more often obese/overweight (p <0.001). Uninsured children (p =0.014), uninsured in past 12 months (p =0.032) and public insurance use (p < 0.001) were more likely to be obese/overweight. Conclusion: Ethnicity, low-income, education, unemployment and food stamp use are associated with increased risk for obesity. Intervention programs for low income families should be guided by social ecology and family system theories to facilitate changes in the home environment to support healthier lifestyles

The Phases and Triviality of Scalar Quantum Electrodynamics

The phase diagram and critical behavior of scalar quantum electrodynamics are investigated using lattice gauge theory techniques. The lattice action fixes the length of the scalar (``Higgs'') field and treats the gauge field as non-compact. The phase diagram is two dimensional. No fine tuning or extrapolations are needed to study the theory's critical behovior. Two lines of second order phase transitions are discovered and the scaling laws for each are studied by finite size scaling methods on lattices ranging from $6^4$ through $24^4$. One line corresponds to monopole percolation and the other to a transition between a ``Higgs'' and a ``Coulomb'' phase, labelled by divergent specific heats. The lines of transitions cross in the interior of the phase diagram and appear to be unrelated. The monopole percolation transition has critical indices which are compatible with ordinary four dimensional percolation uneffected by interactions. Finite size scaling and histogram methods reveal that the specific heats on the ``Higgs-Coulomb'' transition line are well-fit by the hypothesis that scalar quantum electrodynamics is logarithmically trivial. The logarithms are measured in both finite size scaling of the specific heat peaks as a function of volume as well as in the coupling constant dependence of the specific heats measured on fixed but large lattices. The theory is seen to be qualitatively similar to $\lambda\phi^{4}$. The standard CRAY random number generator RANF proved to be inadequateComment: 25pages,26figures;revtex;ILL-(TH)-94-#12; only hardcopy of figures availabl

Finite Size Analysis of the U(1) Background Field Effective Action

We apply the finite size scaling analysis to the derivative of the density of the effective action for the lattice U(1) pure gauge theory in an external constant magnetic field. We found the presence of a continuous phase transition. Moreover, our extimate of of the critical parameters gives values consistent with those extracted from the analysis of the specific heat.Comment: LaTeX2e, 12 pages (5 figures

A novel interplanetary communications relay

A case study of a potential Earth-Mars interplanetary communications relay, designed to ensure continuous communications, is detailed. The relay makes use of orbits based on artificial equilibrium points via the application of continuous low thrust, which allows a spacecraft to hover above the orbital plane of Mars and thus ensure communications when the planet is occulted with respect to the Earth. The artificial equilibria of two different low-thrust propulsion technologies are considered: solar electric propulsion, and a solar sail/solar electric propulsion hybrid. In the latter case it is shown that the combination of sail and solar electric propulsion may prove advantageous, but only under specific circumstances of the relay architecture suggested. The study takes into account factors such as the spacecraft's power requirements and communications band utilized to determine the mission and system architecture. A detailed contingency analysis is considered for recovering the relay after increasing periods of spacecraft motor failure, and combined with a consideration for how best to deploy the relay spacecraft to maximise propellant reserves and mission duration

Prescription pattern of antibiotics in neonatal intensive care unit of tertiary care hospital

Background: Recurrent and prolonged courses of antibiotics exposure have resulted in an increase in the prevalence of hospital acquired infections and antibiotic resistant profile. The objective of this study was to quantify the use of antibiotics in a neonatal intensive care unit (NICU) of Govt. Medical College and Hospital, Aurangabad, Maharashtra, a tertiary health care centre.Methods: A total of 260 neonates admitted in NICU from August 2017 to February 2018 were enrolled in the study and fulfilling inclusion criteria of the study. Demographic details, data on antibiotic prescriptions (name, dose, frequency, route of administration) was recorded on pre-tested structured Performa.Results: A total of 248 neonates received the antibiotics. EOS pneumonia was most common i.e. 29.8% followed by LOS pneumonia (20.6%). Sepsis, pneumonia Meningitis, NEC, were common indications for admission in NICU. Among the antibiotic combinations amoxicillin + clavulanate (38.99%), was most commonly prescribed followed by gentamicin (37.89%) and piperacillin (11.01%) respectively. Other antibiotics like, linezolide (0.94%), fluconazole (5.97%), meropenem (4.42%), vancomycine (0.77%) were also used less commonly in NICU. About fifty of the medicine prescribed were in compliance with the national list of essential medicines 2011.Conclusions: In tertiary care setup of NICU amoxicillin + clavulanate and gentamicin are most commonly used antibiotics in NICU. The study concludes that the antibiotic prescription pattern at NICU of our tertiary care hospital was found rational