Human cytomegalovirus infection, viraemia and retinitis among people living with HIV/AIDS in Kano, North-Western Nigeria

Background: Human cytomegalovirus (HCMV) is a leading cause of opportunistic infection in HIV-infected patients. HCMV viraemia is an active infection marker and prelude to end-organ diseases (EODs), such as retinitis. The aim of the study was to assess the burden and associated factors of HCMV infection, viraemia and retinitis among HIV-infected patients in Nigeria.Methods: Comparative cross-sectional study of 160 HIV-infected adults, comprising 80 participants in each of <100/mm3 and ≥100 cells/mm3 CD4+ cell count groups, who attended HIV clinic at a tertiary hospital located in a major Nigerian city.  A questionnaire was used to collect data from eligible consenting participants and their case files. Sera from all participants were tested for anti-HCMV IgG using ELISA method, and plasma of seropositive participants were subjected to PCR for HCMV viraemia. Participants whose samples were HCMV viraemic were examined for HCMV retinitis using indirect ophthalmoscopy. Data was analyzed using Minitab vs 14.1.1PP.Results: All 160 participants tested positive for anti-HCMV IgG. HCMV viraemia was 14.4% (23 of 160) generally, but comparatively more among <100 CD4 cells/mm3 group (18.8%; 15 of 80) than in ≥100 cells/mm3 patient group (10%; 8 of 80). Only HCMV viraemic patients in <100 CD4 cells/mm3 group (20%; 3 of 15) were diagnosed with HCMV retinitis. WHO stage was associated with HCMV viraemia (χ2= 7.79, p=0.05) and HCMV retinitis (χ2= 4.60, p=0.03). The only predictor of HCMV retinitis was WHO staging I and II [aOR = 0.04, 95%CI (0.01- 0.52)].  Conclusions: Evidence of previous and active HCMV infection is prevalent among PLWHA in Nigeria with WHO staging being associated and a predictor of HCMV viraemia and retinitis, respectively

Antihydrogen studies in ALPHA

he ALPHA experiment studies antihydrogen as a means to investigate the symmetry of matter and antimatter. Spectroscopic studies of the anti-atom hold the promise of the most precise direct comparisons of matter and antimatter possible. ALPHA was the first to trap antihydrogen in a magnetic trap, allowing the first ever detection of atomic transitions in an anti-atom. More recently, through stochastic heating, we have also been able to put a new limit on the charge neutrality of antihydrogen. ALPHA is currently preparing to perform the first laser-spectroscopy of antihydrogen, hoping to excite the 2s state using a two-photon transition from the 1s state. We discuss the recent results as well as the key developments that led to these successes and discuss how we are preparing to perform the first laser-spectroscopy. We will also discuss plans to use our novel technique for gravitational tests on antihydrogen for a direct measurement of the sign of the gravitational force on antihydrogen

Variational calculations for the hydrogen-antihydrogen system with a mass-scaled Born-Oppenheimer potential

The problem of proton-antiproton motion in the ${\rm H}$--${\rm \bar{H}}$ system is investigated by means of the variational method. We introduce a modified nuclear interaction through mass-scaling of the Born-Oppenheimer potential. This improved treatment of the interaction includes the nondivergent part of the otherwise divergent adiabatic correction and shows the correct threshold behavior. Using this potential we calculate the vibrational energy levels with angular momentum 0 and 1 and the corresponding nuclear wave functions, as well as the S-wave scattering length. We obtain a full set of all bound states together with a large number of discretized continuum states that might be utilized in variational four-body calculations. The results of our calculations gives an indication of resonance states in the hydrogen-antihydrogen system

Indirect detection of Dark Matter with the ANTARES Neutrino Telescope

[EN] One of the main objectives of the ANTARES neutrino telescope is the search for neutrinos produced in self-annihilation of Dark Matter (DM) particles. The analysis for different sources of DM (Sun, Galactic Center, Earth, ...) or DM models (SUSY, Secluded) will be described and the results presented. The specific advantages of neutrino telescopes in general and of ANTARES in particular will be explained. As an example, the indirect search for DM towards the Sun performed by neutrino telescopes currently leads to more stringent limits on the spin-dependent WIMP-nucleon cross section with respect to existing direct detection experiments.We acknowledge the financial support of the Spanish Ministerio de Economía y Competitividad, Grants FPA2012-37528-C02-02, and Consolider MultiDark CSD2009-00064, of the Generalitat Valenciana, Grants ACOMP/2015/175 PrometeoII/2014/079 and of the European FEDER funds.Ardid Ramírez, M. (2016). Indirect detection of Dark Matter with the ANTARES Neutrino Telescope. EPJ Web of Conferences. 116:1-5. https://doi.org/10.1051/epjconf/201611604002S1511

Physics with antihydrogen

Performing measurements of the properties of antihydrogen, the bound state of an antiproton and a positron, and comparing the results with those for ordinary hydrogen, has long been seen as a route to test some of the fundamental principles of physics. There has been much experimental progress in this direction in recent years, and antihydrogen is now routinely created and trapped and a range of exciting measurements probing the foundations of modern physics are planned or underway. In this contribution we review the techniques developed to facilitate the capture and manipulation of positrons and antiprotons, along with procedures to bring them together to create antihydrogen. Once formed, the antihydrogen has been detected by its destruction via annihilation or field ionization, and aspects of the methodologies involved are summarized. Magnetic minimum neutral atom traps have been employed to allow some of the antihydrogen created to be held for considerable periods. We describe such devices, and their implementation, along with the cusp magnetic trap used to produce the first evidence for a low-energy beam of antihydrogen. The experiments performed to date on antihydrogen are discussed, including the first observation of a resonant quantum transition and the analyses that have yielded a limit on the electrical neutrality of the anti-atom and placed crude bounds on its gravitational behaviour. Our review concludes with an outlook, including the new ELENA extension to the antiproton decelerator facility at CERN, together with summaries of how we envisage the major threads of antihydrogen physics will progress in the coming years

Antihydrogen and mirror-trapped antiproton discrimination: Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap

Recently, antihydrogen atoms were trapped at CERN in a magnetic minimum (minimum-B) trap formed by superconducting octupole and mirror magnet coils. The trapped antiatoms were detected by rapidly turning off these magnets, thereby eliminating the magnetic minimum and releasing any antiatoms contained in the trap. Once released, these antiatoms quickly hit the trap wall, whereupon the positrons and antiprotons in the antiatoms annihilated. The antiproton annihilations produce easily detected signals; we used these signals to prove that we trapped antihydrogen. However, our technique could be confounded by mirror-trapped antiprotons, which would produce seemingly-identical annihilation signals upon hitting the trap wall. In this paper, we discuss possible sources of mirror-trapped antiprotons and show that antihydrogen and antiprotons can be readily distinguished, often with the aid of applied electric fields, by analyzing the annihilation locations and times. We further discuss the general properties of antiproton and antihydrogen trajectories in this magnetic geometry, and reconstruct the antihydrogen energy distribution from the measured annihilation time history.Comment: 17 figure

Aspects of 1S-2S spectroscopy of trapped antihydrogen atoms

Antihydrogen atoms are now routinely trapped in small numbers. One of the purposes of this effort is to make precision comparisons of the 1S-2S transition in hydrogen and antihydrogen as a precision test of the CPT theorem. We investigate, through calculations and simulations, various methods by which the 1S-2S transition may be probed with only a few trapped atoms. We consider the known constraints from typical experimental geometries, detection methods, sample temperatures, laser light sources etc and we identify a viable path towards a measurement of this transition at the $10^{−1}$1 level in a realistic scenario. We also identify ways in which such a first measurement could be improved upon as a function of projected changes and improvements in antihydrogen synthesis and trapping. These calculations recently guided the first observation of the 1S-2S transition in trapped antihydrogen