Born-Infeld black holes coupled to a massive scalar field

Born-Infeld black holes in the Scalar-Tensor Theories of Gravity, in the case of massless scalar field, have been recently obtained. The aim of the current paper is to study the effect from the inclusion of a potential for the scalar field in the theory, through a combination of analytical techniques and numerical methods. The black holes coupled to a massive scalar field have richer causal structure in comparison to the massless scalar field case. In the latter case, the black holes may have a second, inner horizon. The presence of potential for the scalar field allows the existence of extremal black holes for certain values of the mass of the scalar field and the magnetic (electric) charge of the black hole. The linear stability against spherically symmetric perturbations is studied. Arguments in favor of the general stability of the solutions coming from the application of the "turning point" method are also presented.Comment: 26 pages, 16 figure

Radiation Hardness Studies in a CCD with High-Speed Column Parallel Readout

Charge Coupled Devices (CCDs) have been successfully used in several high energy physics experiments over the past two decades. Their high spatial resolution and thin sensitive layers make them an excellent tool for studying short-lived particles. The Linear Collider Flavour Identification (LCFI) collaboration is developing Column-Parallel CCDs (CPCCDs) for the vertex detector of the International Linear Collider (ILC). The CPCCDs can be read out many times faster than standard CCDs, significantly increasing their operating speed. The results of detailed simulations of the charge transfer inefficiency (CTI) of a prototype CPCCD are reported and studies of the influence of gate voltage on the CTI described. The effects of bulk radiation damage on the CTI of a CPCCD are studied by simulating the effects of two electron trap levels, 0.17 and 0.44 eV, at different concentrations and operating temperatures. The dependence of the CTI on different occupancy levels (percentage of hit pixels) and readout frequencies is also studied. The optimal operating temperature for the CPCCD, where the effects of the charge trapping are at a minimum, is found to be about 230 K for the range of readout speeds proposed for the ILC. The results of the full simulation have been compared with a simple analytic model.Comment: 3 pages, 6 figures; presented at IEEE'07, ALCPG'07, ICATPP'0

Topical intranasal analgesia with EMLA for closed rhinoplasty

Background: Rhinoplasty is a traumatic procedure associated with postoperative pain. The purpose of this study is to determine the effect of topically administered intranasal EMLA 5% cream (lidocaine 25 mg/ prilocaine 25 mg) on the pain experienced in the postoperative period by patients who underwent closed rhinoplasty.Materials and methods: The study was conducted between October 2014 and May 2016 and included 66 patients divided in two groups, all of whom underwent closed rhinoplasty. In the first group (n = 33) when packaging and placing the nasal splint, each intranasal tampon (with Gelaspon) was applied with 2 ml EMLA 5% cream, and in the control group (n = 33) 2 ml Deflamol ointment was applied on each tampon. All patients were operated under general anesthesia after introduction with intravenous Propofol and maintenance of the anesthesia with Sevoflurane and opioid analgesic. After placing the patient under general anesthesia, the otorhinolaryngologist carries on with local infiltration anesthesia with a solution of lidocaine 0.5%and adrenaline 1: 100,000 4-6 ml. All patients received oral antibiotic treatment (with Klacid or Zinnat) for the period of the packaging. No corticosteroids were included in the therapeutic scheme. Post-operative pain was assessed on a visual analog scale on the 1, 3, 6, 12, 24, 48 hour in the patients of both groups.Results: The statistical analysis shows that there is a significant differencein reported results for the treatment of post-operative pain on the 1, 6 and 12 hour period in both groups studied. Four of the patients (12%) in the EMLA group had results from the VAS > 40 mm and required administration of a non-opioid analgesic in the first 24 hours, whilst in the control group this number of patients was 13 (39%).Conclusion: Intranasal application EMLA 5% cream in the packaging for reducing postoperative pain in patients who underwent closed rhinoplasty proves to be a simple and effective technique, in which we have not found adverse side effects in the study group patients despite this off label usage

Development of an ASIC for CCD readout at the vertex detectors of the intrenational linear collider

The Linear Collider Flavour Identification Collaboration is developing sensors and readout electronics suitable for the International Linear Collider vertex detector. In order to achieve high data rates the proposed detector utilises column parallel CCDs, each read out by a custom designed ASIC. The prototype chip (CPR2) has 250 channels of electronics, each with a preamplifier, 5-bit flash ADC, data sparsification logic for identification of significant data clusters, and local memory for storage of data awaiting readout. CPR2 also has hierarchical 2-level data multiplexing and intermediate data memory, enabling readout of the sparsified data via the 5-bit data output bus

Scalar-tensor black holes coupled to Born-Infeld nonlinear electrodynamics

The non-existence of asymptotically flat, neutral black holes and asymptotically flat, charged black holes in the Maxwell electrodynamics, with non-trivial scalar field has been proved for a large class of scalar-tensor theories. The no-scalar-hair theorems, however, do not apply in the case of non-linear electrodynamics. In the present work numerical solutions describing charged black holes coupled to Born-Infeld type non-linear electrodynamics in scalar-tensor theories of gravity with massless scalar field are found. The causal structure and properties of the solutions are studied, and a comparison between these solutions and the corresponding solutions in the General Relativity is made. The presence of the scalar field leads to a much more simple causal structure. The present class of black holes has a single, non-degenerate horizon, i.e., its causal structure resembles that of the Schwarzschild black hole.Comment: 12 pages, 4 figures, PR

Bridging the Gap Between Scientists and Classrooms: Scientist Engagement in the Expedition Earth and Beyond Program

Teachers in today s classrooms need to find creative ways to connect students with science, technology, engineering, mathematics (STEM) experts. These STEM experts can serve as role models and help students think about potential future STEM careers. They can also help reinforce academic knowledge and skills. The cost of transportation restricts teachers ability to take students on field trips exposing them to outside experts and unique learning environments. Additionally, arranging to bring in guest speakers to the classroom seems to happen infrequently, especially in schools in rural areas. The Expedition Earth and Beyond (EEAB) Program [1], facilitated by the Astromaterials Research and Exploration Science (ARES) Directorate Education Program at the NASA Johnson Space Center has created a way to enable teachers to connect their students with STEM experts virtually. These virtual connections not only help engage students with role models, but are also designed to help teachers address concepts and content standards they are required to teach. Through EEAB, scientists are able to actively engage with students across the nation in multiple ways. They can work with student teams as mentors, participate in virtual student team science presentations, or connect with students through Classroom Connection Distance Learning (DL) Events

Optical spectroscopy of Be stars: peak separation of Balmer emission lines

The Be stars display variable optical emission lines originating in the circumstellar disc. Here we analyse high resolution spectroscopic observations of Be stars and the distance between the peaks of H-alpha, H-beta, and H-gamma emission lines ($\Delta V_\alpha$, $\Delta V_\beta$, and $\Delta V_\gamma$ respectively). Combining published data, spectra from the ELODIE archive (obtained in the period 1998 -- 2003) and Rozhen spectra (obtained 2015 -- 2023) of 93 Be stars, we find a set of relations connecting $\Delta V_\alpha$, $\Delta V_\beta$ and $\Delta V_\gamma$. They are effective for $30 \le \Delta V_\alpha \le 500$ km s$^{-1}$, $80 \le \Delta V_\beta \le 600$ km s$^{-1}$, and $40 \le \Delta V_\gamma \le 300$ km s$^{-1}$. The new equations are in the form $y=ax + b$ and are valid for a wider velocity range than in previous studies.Comment: Astronomische Nachrichten (accepted