The optimum phase demodulator for interfering PM subcarrier signals

Optimum phase demodulator for interfering PM subcarrier signal

A phase locked loop demodulator for television type PM signals

Phased-locked loop demodulator for television type PM signals on sinusoidal carrie

Hubble Space Telescope observations of the NUV transit of WASP-12b

We present new observations of four closely-spaced NUV transits of the hot Jupiter-like exoplanet WASP-12b using HST/COS, significantly increasing the phase resolution of the observed NUV light curve relative to previous observations, while minimising the temporal variation of the system. We observe significant excess NUV absorption during the transit, with mean normalised in-transit fluxes of $F_\mathrm{norm}\simeq0.97$, i.e. $\simeq$2-5 $\sigma$ deeper than the optical transit level of $\simeq0.986$ for a uniform stellar disk (the exact confidence level depending on the normalisation method used). We further observe an asymmetric transit shape, such that the post-conjunction fluxes are overall $\simeq$2-3 $\sigma$ higher than pre-conjunction values, and characterised by rapid variations in count rate between the pre-conjunction and out of transit levels. We do not find evidence for an early ingress to the NUV transit as suggested by earlier HST observations. However, we show that the NUV count rate observed prior to the optical transit is highly variable, but overall $\simeq$2.2-3.0 $\sigma$ below the post-transit values and comparable in depth to the optical transit, possibly forming a variable region of NUV absorption from at least phase $\phi\simeq$0.83, limited by the data coverage.Comment: Accepted into the Astrophysical Journa

Issues and Opinions: Assessing the Emphasis on Information Security in the Systems Analysis and Design Course

Due to several recent highly publicized information breaches, information security has gained a higher profile. Hence, it is reasonable to expect that information security would receive an equally significant emphasis in the education of future systems professionals. A variety of security standards that various entities (e.g., NIST, COSO, ISACA-COBIT, ISO) have put forth emphasize the importance of information security from the very beginning of the system development lifecycle (SDLC) to avoid significant redesign in later phases. To determine the emphasis on security in typical systems analysis and design (SA&D) courses, we examine (1) to what extent security is emphasized in the core SA&D courses and (2) at what phase in the SDLC do most SA&D courses begin to emphasize security. In order to address these questions, we reviewed SA&D textbooks currently on the market to identify how extensively they cover security-related issues. Given the fairly high awareness of information security in practice, we expected to see an equally high emphasis on such matters in the textbooks. However, our review suggests that this is not the case, which suggests a gap in our preparation. To address this gap, we offer a proposal for modifying a portion of the SA&D curricula

Origin of electron cyclotron maser-induced radio emissions at ultra-cool dwarfs: magnetosphere-ionosphere coupling currents

A number of ultra-cool dwarfs emit circularly polarised radio waves generated by the electron cyclotron maser instability. In the solar system such radio is emitted from regions of strong auroral magnetic field-aligned currents. We thus apply ideas developed for Jupiter's magnetosphere, being a well-studied rotationally-dominated analogue in our solar system, to the case of fast-rotating UCDs. We explain the properties of the radio emission from UCDs by showing that it would arise from the electric currents resulting from an angular velocity shear in the fast-rotating magnetic field and plasma, i.e. by an extremely powerful analogue of the process which causes Jupiter's auroras. Such a velocity gradient indicates that these bodies interact significantly with their space environment, resulting in intense auroral emissions. These results strongly suggest that auroras occur on bodies outside our solar system.Comment: Accepted for publication in the Astrophysical Journa

Adaptation of an evidence-based cardiovascular health intervention for rural African Americans in the Southeast

Background: African Americans (AA) living in the southeast United States have the highest prevalence of cardiovascular diseases (CVD) and rural minorities bear a significant burden of co-occurring CVD risk factors. Few evidence-based interventions (EBI) address social and physical environmental barriers in rural minority communities. We used intervention mapping together with community-based participatory research (CBPR) principles to adapt objectives of a multi-component CVD lifestyle EBI to fit the needs of a rural AA community. We sought to describe the process of using CPBR to adapt an EBI using intervention mapping to an AA rural setting and to identify and document the adaptations mapped onto the EBI and how they enhance the intervention to meet community needs. Methods: Focus groups, dyadic interviews, and organizational web-based surveys were used to assess content interest, retention strategies, and incorporation of auxiliary components to the EBI. Using CBPR principles, community and academic stakeholders met weekly to collaboratively integrate formative research findings into the intervention mapping process. We used a framework developed by Wilstey Stirman et al. to document changes. Results: Key changes were made to the content, context, and training and evaluation components of the existing EBI. A matrix including behavioral objectives from the original EBI and new objectives was developed. Categories of objectives included physical activity, nutrition, alcohol, and tobacco divided into three levels, namely, individual, interpersonal, and environmental. Conclusions: Intervention mapping integrated with principles of CBPR is an efficient and flexible process for adapting a comprehensive and culturally appropriate lifestyle EBI for a rural AA community context

Active vibration mitigation of distributed parameter, smart-type structures using Pseudo-Feedback Optimal Control (PFOC)

A new, near-optimal feedback control technique is introduced that is shown to provide excellent vibration attenuation for those distributed parameter systems that are often encountered in the areas of aeroservoelasticity and large space systems. The technique relies on a novel solution methodology for the classical optimal control problem. Specifically, the quadratic regulator control problem for a flexible vibrating structure is first cast in a weak functional form that admits an approximate solution. The necessary conditions (first-order) are then solved via a time finite-element method. The procedure produces a low dimensional, algebraic parameterization of the optimal control problem that provides a rigorous basis for a discrete controller with a first-order like hold output. Simulation has shown that the algorithm can successfully control a wide variety of plant forms including multi-input/multi-output systems and systems exhibiting significant nonlinearities. In order to firmly establish the efficacy of the algorithm, a laboratory control experiment was implemented to provide planar (bending) vibration attenuation of a highly flexible beam (with a first clamped-free mode of approximately 0.5 Hz)

The effect of active immunization against adrenocorticotropic hormone on cortisol, beta-endorphin, vocalization, and growth in pigs

Because the poor growth performance of intensively housed pigs is associated with increased circulating glucocorticoid concentrations, we investigated the effects of glucocorticoid suppression by inducing a humoral immune response to ACTH on physiological and production variables in growing pigs. Grower pigs (28.6 0.9 kg) were immunized with amino acids 1 through 24 of ACTH conjugated to ovalbumin and suspended in diethylaminoethyl (DEAE) dextran-adjuvant or adjuvant alone (control) on d 1, 28, and 56. The ACTH-specific antibody titers generated suppressed increases in cortisol concentrations on d 63 in response to an acute stressor (P = 0.002; control = 71 +/- 8.2 ng/ mL; ACTH-immune = 43 +/- 4.9 ng/mL) without altering basal concentrations. Plasma beta-endorphin concentrations were also increased (P < 0.001) on d 63 (control = 18 +/- 2.1 ng/mL; ACTH-immune = 63 +/- 7.3 ng/mL), presumably because of a release from negative feedback on the expression of proopiomelanocortin in pituitary corticotropes. Immunization against ACTH did not alter ADG (P = 0.120; control = 1,077 25; ACTH-immune = 1,143 25 g) or ADFI (P = 0.64; control = 2,719 42; ACTH-immune = 2,749 42 g) and did not modify behavior (P = 0.681) assessed by measuring vocalization in response to acute restraint. In summary, suppression of stress-induced cortisol responses through ACTH immunization increased beta-endorphin concentrations, but it did not modify ADG, ADFI, or restraint vocalization score in growing pigs

A LOFAR mini-survey for low-frequency radio emission from the nearest brown dwarfs

We have conducted a mini-survey for low-frequency radio emission from some of the closest brown dwarfs to the Sun with rapid rotation rates: SIMP J013656.5 +093347, WISEPC 150649.97+702736.0, and WISEPA J174124.26+255319.5.We have placed robust 3s upper limits on the flux density in the 111 – 169 MHz frequency range for these targets: WISE 1506: &lt; 0:72 mJy; WISE 1741: &lt; 0:87 mJy; SIMP 0136: &lt; 0:66 mJy. At 8 hours of integration per target to achieve these limits, we find that systematic and detailed study of this class of object at LOFAR frequencies will require a substantial dedication of resources

Diamagnetic Blob Interaction Model of T Tauri Variability

Assuming a diamagnetic interaction between a stellar-spot originated localized magnetic field and gas blobs in the accretion disk around a T- Tauri star, we show the possibility of ejection of such blobs out of the disk plane. Choosing the interaction radius and the magnetic field parameters in a suitable way gives rise to closed orbits for the ejected blobs. A stream of matter composed of such blobs, ejected on one side of the disk and impacting on the other, can form a hot spot at a fixed position on the disk (in the frame rotating with the star). Such a hot spot, spread somewhat by disk shear before cooling, may be responsible in some cases for the lightcurve variations observed in various T-Tauri stars over the years. An eclipse-based mechanism due to stellar obscuration of the spot is proposed. Assuming high disk inclination angles it is able to explain many of the puzzling properties of these variations. By varying the field parameters and blob initial conditions we obtain variations in the apparent angular velocity of the hot spot, producing a constantly changing period or intermittent periodicity disappearance in the models.Comment: 6 pages, 4 figures, aas2pp4 styl