Is Sextans dwarf galaxy in a scalar field dark matter halo?

The Bose-Einstein condensate/scalar field dark matter model, considers that the dark matter is composed by spinless-ultra-light particles which can be described by a scalar field. This model is an alternative model to the $\Lambda$-cold dark matter paradigm, and therefore should be studied at galactic and cosmological scales. Dwarf spheroidal galaxies have been very useful when studying any dark matter theory, because the dark matter dominates their dynamics. In this paper we study the Sextans dwarf spheroidal galaxy, embedded in a scalar field dark matter halo. We explore how the dissolution time-scale of the stellar substructures in Sextans, constrain the mass, and the self-interacting parameter of the scalar field dark matter boson. We find that for masses in the range $(0.12< m_{\phi}<8) \times10^{-22}$~eV, scalar field dark halos without self-interaction would have cores large enough to explain the longevity of the stellar substructures in Sextans, and small enough mass to be compatible with dynamical limits. If the self-interacting parameter is distinct to zero, then the mass of the boson could be as high as $m_{\phi}\approx2\times10^{-21}$~eV, but it would correspond to an unrealistic low mass fot the Sextans dark matter halo . Therefore, the Sextans dwarf galaxy could be embedded in a scalar field/BEC dark matter halo with a preferred self-interacting parameter equal to zero.Comment: 18 pages, 5 figures, 1 table. Submitted to JCA

Amplification of Angular Rotations Using Weak Measurements

We present a weak measurement protocol that permits a sensitive estimation of angular rotations based on the concept of weak-value amplification. The shift in the state of a pointer, in both angular position and the conjugate orbital angular momentum bases, is used to estimate angular rotations. This is done by an amplification of both the real and imaginary parts of the weak-value of a polarization operator that has been coupled to the pointer, which is a spatial mode, via a spin-orbit coupling. Our experiment demonstrates the first realization of weak-value amplification in the azimuthal degree of freedom. We have achieved effective amplification factors as large as 100, providing a sensitivity that is on par with more complicated methods that employ quantum states of light or extremely large values of orbital angular momentum.Comment: 5 pages, 3 figures, contains supplementary informatio

Duplicate detection methodology for IP network traffic analysis

Network traffic monitoring systems have to deal with a challenging problem: the traffic capturing process almost invariably produces duplicate packets. In spite of this, and in contrast with other fields, there is no scientific literature addressing it. This paper establishes the theoretical background concerning data duplication in network traffic analysis: generating mechanisms, types of duplicates and their characteristics are described. On this basis, a duplicate detection and removal methodology is proposed. Moreover, an analytical and experimental study is presented, whose results provide a dimensioning rule for this methodology.Comment: 7 pages, 8 figures. For the GitHub project, see https://github.com/Enchufa2/nantool

Rapid Generation of Light Beams Carrying Orbital Angular Momentum

We report a technique for encoding both amplitude and phase variations onto a laser beam using a single digital micro-mirror device (DMD). Using this technique, we generate Laguerre-Gaussian and vortex orbital-angular-momentum (OAM) modes, along with modes in a set that is mutually unbiased with respect to the OAM basis. Additionally, we have demonstrated rapid switching among the generated modes at a speed of 4 kHz, which is much faster than the speed regularly achieved by spatial light modulators (SLMs). The dynamic control of both phase and amplitude of a laser beam is an enabling technology for classical communication and quantum key distribution (QKD) systems that employ spatial mode encoding

Testing cosmic acceleration for w(z)w(z) parameterizations using fgasf_{gas} measurements in galaxy clusters

In this paper we study the cosmic acceleration for five dynamical dark energy models whose equation of state varies with redshift. The cosmological parameters of these models are constrained by performing a MCMC analysis using mainly gas mass fraction, $f_{gas}$, measurements in two samples of galaxy clusters: one reported by Allen et al. (2004), which consists of $42$ points spanning the redshift range $0.05<z<1.1$, and the other by Hasselfield et al. (2013) from the Atacama Cosmology Telescope survey, which consists of $91$ data points in the redshift range $0.118 < \mathrm{z} < 1.36$. In addition, we perform a joint analysis with the measurements of the Hubble parameter $H(z)$, baryon acoustic oscillations and the cosmic microwave background radiation from WMAP and Planck measurements to estimate the equation of state parameters. We obtained that both $f_{gas}$ samples provide consistent constraints on the cosmological parameters. We found that the $f_{gas}$ data is consistent at the $2\sigma$ confidence level with a cosmic slowing down of the acceleration at late times for most of the parameterizations. The constraints of the joint analysis using WMAP and Planck measurements show that this trend disappears. We have confirmed that the $f_{gas}$ probe provides competitive constraints on the dark energy parameters when a $w(z)$ is assumed.Comment: 21 pages, 8 Tables, 11 Figures, accepted for publication in MNRA

Constraints on barotropic dark energy models by a new phenomenological q(z)q(z) parameterization

In this paper, we propose a new phenomenological two parameter parametrization of $q(z)$ to constrain barotropic dark energy models by considering a spatially flat FRW universe, neglecting the radiation component, and reconstructing the effective equation of state (EoS). This two free-parameter EoS reconstruction shows a non-monotonic behavior, pointing to a more general fitting for the scalar field models, like thawing and freezing models. We constrain the $q(z)$ free parameters using the observational data of the Hubble parameter obtained from cosmic chronometers, the joint-light-analysis type Ia Supernovae sample and a joint analysis from these data. We obtain a value of $q(z)$ today, $q_0=-0.48\substack{+0.10 -0.11}$, and a transition redshift, $z_t=0.71\substack{+0.12 -0.12}$ (when the Universe change from an decelerated phase to an accelerated one). The effective EoS reconstruction and the $\omega'$-$\omega$ plane analysis pointed out a quintom dark energy, which is consistent with a non parametric EoS reconstruction, reported by other authors, and using the latest cosmological observations.Comment: This manuscript was accepted to be published in the European Physical Journal C. 17 pages, 7 figures, 1 tabl

Development of an Automated Multiple Material Stereolithography Machine

An automated Multiple Material Stereolithography (MMSL) machine was developed by integrating components of a 3D Systems 250/50 stereolithography (SL) machine in a separate stand-alone system and adapting them to function with additional components required for MMSL operation. We previously reported retrofitting a 250/50 SL machine with multiple vats to accommodate multiple material fabrication for building a wide variety of multi-material models (Wicker et al., 2004). In the MMSL retrofit, spatial constraints limited the multiple vats located circumferentially on a vertical rotating vat carousel to cross-sectional areas of approximately 4.5-inches by 4.5-inches. The limited build size of the retrofitted 250/50 motivated the full development of a new system with multiple material build capabilities comparable to the build envelope of the original 250/50 machine. The new MMSL machine required fabrication of a large system frame, incorporating various 250/50 components and software, and adding a variety of new components and software. By using many existing components and software, the previous engineering development of 3D Systems could be directly applied to this new technology. Components that were transferred from an existing 250/50 to the MMSL machine included the complete optical system (including the optics plate with laser, mirrors, beam expander, scanning mirrors, and focusing lens), the rim assembly (including the laser beam profilers), the associated controllers (computer system, scanning mirror controller, power supply-vat controller) and the wiring harness. In addition to the new frame, the MMSL machine required the development of a new rotating vat carousel system, platform assembly, multi-pump filling/leveling system, and a custom LabVIEW® control system to provide automated control over the MMSL process. The overall operation of the MMSL system was managed using the LabVIEW® program, which also included controlling a new vat leveling system and new linear and rotational stages, while the 3D Systems software (Buildstation 4.0) was retained for controlling the laser scanning process. As a demonstration of MMSL technology, simple multi material parts were fabricated with vertically and horizontally oriented interfaces. The fully functional MMSL system offers enormous potential for fabricating a wide variety of multiple material functional devices.Mechanical Engineerin

How Do Communities Use a Participatory Public Health Approach to Build Resilience? The Los Angeles County Community Disaster Resilience Project.

Community resilience is a key concept in the National Health Security Strategy that emphasizes development of multi-sector partnerships and equity through community engagement. Here, we describe the advancement of CR principles through community participatory methods in the Los Angeles County Community Disaster Resilience (LACCDR) initiative. LACCDR, an initiative led by the Los Angeles County Department of Public Health with academic partners, randomized 16 community coalitions to implement either an Enhanced Standard Preparedness or Community Resilience approach over 24 months. Facilitated by a public health nurse or community educator, coalitions comprised government agencies, community-focused organizations and community members. We used thematic analysis of data from focus groups (n = 5) and interviews (n = 6 coalition members; n = 16 facilitators) to compare coalitions' strategies for operationalizing community resilience levers of change (engagement, partnership, self-sufficiency, education). We find that strategies that included bidirectional learning helped coalitions understand and adopt resilience principles. Strategies that operationalized community resilience levers in mutually reinforcing ways (e.g., disseminating information while strengthening partnerships) also secured commitment to resilience principles. We review additional challenges and successes in achieving cross-sector collaboration and engaging at-risk groups in the resilience versus preparedness coalitions. The LACCDR example can inform strategies for uptake and implementation of community resilience and uptake of the resilience concept and methods