2,208 research outputs found

    Neutrino Oscillation Observables from Mass Matrix Structure

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    We present a systematic procedure to establish a connection between complex neutrino mass matrix textures and experimental observables, including the Dirac CP phase. In addition, we illustrate how future experimental measurements affect the selection of textures in the (theta_13,delta_CP)-plane. For the mixing angles, we use generic assumptions motivated by quark-lepton complementarity. We allow for any combination between U_l and U_nu, as well as we average over all present complex phases. We find that individual textures lead to very different distributions of the observables, such as to large or small leptonic CP violation. In addition, we find that the extended quark-lepton complementarity approach motivates future precision measurements of delta_CP at the level of theta_C \simeq 11 degrees.Comment: Version to appear in Phys. Lett. B. A complete list of textures can be found at http://theorie.physik.uni-wuerzburg.de/~winter/Resources/CTex/index.html . 7 pages, 1 figure, 1 tabl

    Characterization of SPECC1L Function in Palatogenesis

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    Orofacial clefts are among the most common congenital birth defects, occurring in as many as 1 in 800 births worldwide. Genetic and environmental factors contribute to the complex etiology of these anomalies. SPECC1L encodes a cytoskeletal protein with roles in adhesion, migration, and cytoskeletal organization. SPECC1L mutations have been identified in patients with atypical clefts, Opitz G/BBB syndrome, and Teebi hypertelorism syndrome. Our lab has previously shown that knockout of Specc1l in mice with gene trap alleles results in early embryonic lethality with defects in neural tube closure and neural crest cell delamination, as well as reduced PI3K-AKT signaling. However, the early lethality phenotype rendered these models incapable of recapitulating the human anomalies. To validate a role for SPECC1L in palatogenesis, we generated additional gene trap and truncation mutant Specc1l alleles. Specc1lgenetrap/truncation compound heterozygote embryos survive to the perinatal period, allowing analysis at later developmental stages. Examination of compound mutant palates revealed a delay in palate elevation, abnormal oral adhesions, and ectopic expression of adherens junction protein β-catenin at the apical surface of oral epithelial periderm cells, as well as a global increase in actin filament staining. We also establish that transcription factor IRF6, which has a causative role in many cases of orofacial clefting, is required for SPECC1L expression in the palate. After establishing a role for SPECC1L in the palatal epithelium, we asked if it also acted in the migration of palatal mesenchyme. Indeed, time-lapse imaging analysis of primary mouse embryonic palatal mesenchyme (MEPM) cells from Specc1lgenetrap/truncation mutant embryos show defects in migration. We also demonstrate that activation of the PI3K-AKT pathway with a small molecule activator improves mutant wound closure speed. Furthermore, random 2-D motility cultures revealed that MEPM cells have attributes of collective migration that are reduced in mutant cells. Lastly, we generated a mouse allele with the T397P point mutation, located in the second coiled-coil domain (CCD2) of SPECC1L, that was previously identified in patients with Opitz G/BBB syndrome. Embryos with this allele displayed omphalocele and completely penetrant cleft palate defects that recapitulated the phenotype of patients with SPECC1L mutations. Together, these data identify roles for SPECC1L in palate epithelial integrity and mesenchymal remodeling, and thus firmly establish a requirement for SPECC1L in palatogenesis

    NASA Accident Precursor Analysis Handbook, Version 1.0

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    Catastrophic accidents are usually preceded by precursory events that, although observable, are not recognized as harbingers of a tragedy until after the fact. In the nuclear industry, the Three Mile Island accident was preceded by at least two events portending the potential for severe consequences from an underappreciated causal mechanism. Anomalies whose failure mechanisms were integral to the losses of Space Transportation Systems (STS) Challenger and Columbia had been occurring within the STS fleet prior to those accidents. Both the Rogers Commission Report and the Columbia Accident Investigation Board report found that processes in place at the time did not respond to the prior anomalies in a way that shed light on their true risk implications. This includes the concern that, in the words of the NASA Aerospace Safety Advisory Panel (ASAP), "no process addresses the need to update a hazard analysis when anomalies occur" At a broader level, the ASAP noted in 2007 that NASA "could better gauge the likelihood of losses by developing leading indicators, rather than continue to depend on lagging indicators". These observations suggest a need to revalidate prior assumptions and conclusions of existing safety (and reliability) analyses, as well as to consider the potential for previously unrecognized accident scenarios, when unexpected or otherwise undesired behaviors of the system are observed. This need is also discussed in NASA's system safety handbook, which advocates a view of safety assurance as driving a program to take steps that are necessary to establish and maintain a valid and credible argument for the safety of its missions. It is the premise of this handbook that making cases for safety more experience-based allows NASA to be better informed about the safety performance of its systems, and will ultimately help it to manage safety in a more effective manner. The APA process described in this handbook provides a systematic means of analyzing candidate accident precursors by evaluating anomaly occurrences for their system safety implications and, through both analytical and deliberative methods used to project to other circumstances, identifying those that portend more serious consequences to come if effective corrective action is not taken. APA builds upon existing safety analysis processes currently in practice within NASA, leveraging their results to provide an improved understanding of overall system risk. As such, APA represents an important dimension of safety evaluation; as operational experience is acquired, precursor information is generated such that it can be fed back into system safety analyses to risk-inform safety improvements. Importantly, APA utilizes anomaly data to predict risk whereas standard reliability and PRA approaches utilize failure data which often is limited and rare

    Assessing the Effectiveness of a Bedtime Behavioral Intervention for Military Children with a Deployed Parent

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    While there are advantages and disadvantages to the lifestyle of a military family, challenges often include frequent moves, stressful military work environments, and deployments of the active duty member to dangerous war zones. Military children often display an array of internalizing and externalizing problems, with one common problem being disrupted sleep. The purpose of the current study was to evaluate the use of current technology to minimize problematic sleep behaviors affecting young children with a recently deployed parent. The intervention required parents to show their child a previously recorded DVD of the deployed parent reading a children’s book prior to the child’s bedtime. Sleep diary data were collected for two children who had been previously identified as having significant bedtime resistant behavior. A nonconcurrent, multiple-baselines across participants research design was used to evaluate data with two data collection phases for both participants. Analyses revealed considerable reductions in the number of bedtime resistant behaviors post-intervention and large effect sizes were yielded for the intervention phases for both participants. Implications for clinical practice are discussed

    Environmental communications: The reader’s perspective

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    Connecting reception theory and social semiotics, this article offers a framework for the analysis of hortatory texts. An illustrative case uses the pronouncements of environmental regulators, with the reader group represented by a sample of executives in financial institutions. Although the participants thought the texts important, none had found any use for them. It is unlikely that financial institutions en masse will address environmental issues before and until communicators frame their material in terms of customary financial discourse and investors’ dominant cognitive rationalities. The depth of insights gained suggests wider application of the framework to a range of hortatory texts and authoritative reader groups

    On the diversity and complexity of absorption line profiles produced by outflows in Active Galactic Nuclei

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    Understanding the origin of AGN absorption line profiles and their diversity could help to explain the physical structure of the accretion flow, and also to assess the impact of accretion on the evolution of the AGN host galaxies. Here we present our first attempt to systematically address the issue of the origin of the complexities observed in absorption profiles. Using a simple method, we compute absorption line profiles against a continuum point source for several simulations of accretion disk winds. We investigate the geometrical, ionization, and dynamical effects on the absorption line shapes. We find that significant complexity and diversity of the absorption line profile shapes can be produced by the non-monotonic distribution of the wind velocity, density, and ionization state. Non-monotonic distributions of such quantities are present even in steady-state, smooth disk winds, and naturally lead to the formation of multiple and detached absorption troughs. These results demonstrate that the part of a wind where an absorption line is formed is not representative of the entire wind. Thus, the information contained in the absorption line is incomplete if not even insufficient to well estimate gross properties of the wind such as the total mass and energy fluxes. In addition, the highly dynamical nature of certain portions of disk winds can have important effects on the estimates of the wind properties. For example, the mass outflow rates can be off up to two orders of magnitude with respect to estimates based on a spherically symmetric, homogeneous, constant velocity wind.Comment: 10 pages, 10 figures, to appear in Ap

    VLT + UVES Spectroscopy of the Low-Ionization Intrinsic Absorber in SDSS J001130.56+005550.7

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    We analyse high-resolution VLT+UVES spectra of the low-ionization intrinsic absorber observed in the BAL QSO SDSS J001130.56+005550.7. Two narrow absorption systems at velocities -600 km/s and -22000 km/s are detected. The low-velocity system is part of the broad absorption line (BAL), while the high-velocity one is well detached. While most narrow absorption components are only detected in the high-ionization species, the lowest velocity component is detected in both high- and low-ionization species, including in the excited SiII* and CII* lines. From the analysis of doublet lines, we find that the narrow absorption lines at the low-velocity end of the BAL trough are completely saturated but do not reach zero flux, their profiles being dominated by a velocity-dependent covering factor. The covering factor is significantly smaller for MgII than for SiIV and NV, which demonstrates the intrinsic nature of absorber. From the analysis of the excited SiII* and CII* lines in the lowest velocity component, we find an electron density ~ 1000 cm^{-3}. Assuming photoionization equilibrium, we derive a distance ~ 20 kpc between the low-ionization region and the quasar core. The correspondence in velocity of the high- and low-ionization features suggests that all these species must be closely associated, hence formed at the same distance of ~ 20 kpc, much higher than the distance usually assumed for BAL absorbers.Comment: Accepted for publication in A&

    Acceleration and Substructure Constraints in a Quasar Outflow

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    We present observations of probable line-of-sight acceleration of a broad absorption trough of C IV in the quasar SDSS J024221.87+004912.6. We also discuss how the velocity overlap of two other outflowing systems in the same object constrains the properties of the outflows. The Si IV doublet in each system has one unblended transition and one transition which overlaps with absorption from the other system. The residual flux in the overlapping trough is well fit by the product of the residual fluxes in the unblended troughs. For these optically thick systems to yield such a result, at least one of them must consist of individual subunits rather than being a single structure with velocity-dependent coverage of the source. If these subunits are identical, opaque, spherical clouds, we estimate the cloud radius to be r = 3.9 10^15 cm. If they are identical, opaque, linear filaments, we estimate their width to be w = 6.5 10^14 cm. These subunits are observed to cover the Mg II broad emission line region of the quasar, at which distance from the black hole the above filament width is equal to the predicted scale height of the outer atmosphere of a thin accretion disk. Insofar as that scale height is a natural size scale for structures originating in an accretion disk, these observations are evidence that the accretion disk can be a source of quasar absorption systems. Based on data from ESO program 075.B-0190(A).Comment: 14 emulateapj pages, 7 figures, ApJ in pres

    Discovery of Balmer Broad Absorption Lines in the Quasar LBQS 1206+1052

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    We report the discovery of Balmer broad absorption lines (BALs) in the quasar LBQS 1206+1052 and present a detailed analysis of the peculiar absorption line spectrum. Besides Mg II λλ2796,2803\lambda \lambda 2796, 2803 doublet, BALs are also detected in He I* multiplet at λλ2946,3189,3889\lambda \lambda 2946, 3189, 3889 \AA arising from metastable helium 23S2^3S level, and in Hα\alpha and Hβ\beta from excited hydrogen H I* n=2n=2 level, which are rarely seen in quasar spectra. We identify two components in the BAL troughs of Δv\Delta v\sim2000 km s1^{-1} width: One component shows an identical profile in H I*, \hei* and \mgii with its centroid blueshifted by vc726-v_{\rm c}\approx 726 km\ s1^{-1}. The other component is detected in \hei* and \mgii with vc1412-v_{\rm c}\approx 1412 km s1^{-1}. We estimate the column densities of H I*, He I*, and Mg II, and compare them with possible level population mechanisms. Our results favor the scenario that the Balmer BALs originate in a partially ionized region with a column density of NH102122N_{\rm H}\sim 10^{21-22} cm2^{-2} for an electron density of ne1068n_e\sim 10^{6-8} cm3^{-3} via Lyα\alpha resonant scattering pumping. The harsh conditions needed may help to explain the rarity of Balmer absorption line systems in quasar spectra. With an ii-band PSF magnitude of 16.50, LBQS 1206+1052 is the brightest Balmer-BAL quasar ever reported. Its high brightness and unique spectral properties make LBQS 1206+1052 a promising candidate for follow-up high-resolution spectroscopy, multi-band observations, and long-term monitoring.Comment: 16 pages,4 figure
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