Charge Asymmetric Cosmic Ray Signals From Dark Matter Decay

The PAMELA and Fermi measurements of the cosmic-ray electron and positron spectra have generated much interest over the past two years, because they are consistent with a significant component of the electron and positron fluxes between 20 GeV and 1 TeV being produced through dark matter annihilation or decay. However, since the measurements are also consistent with astrophysical interpretations, the message is unclear. In this paper, we point out that dark matter can have a more distinct signal in cosmic rays, that of a charge asymmetry. Such charge asymmetry can result if the dark matter's abundance is due to a relic asymmetry, allowing its decay to generate an asymmetry in positrons and electrons. This is analogous to the baryon asymmetry, where decaying neutrons produce electrons and not positrons. We explore benchmark scenarios where the dark matter decays into a leptophilic charged Higgs boson or electroweak gauge bosons. These models have observable signals in gamma rays and neutrinos, which can be tested by Fermi and IceCube. The most powerful test will be at AMS-02, given its ability to distinguish electron and positron charge above 100 GeV. Specifically, an asymmetry favoring positrons typically predicts a larger positron ratio and a harder (softer) high energy spectrum for positrons (electrons) than charge symmetric sources. We end with a brief discussion on how such scenarios differ from the leading astrophysical explanations.Comment: 8 pages, 11 figures, revtex; v2, additional references adde

TRANSCRIPTIONAL AND TRANSLATIONAL CONTROL OF ZEBRAFISH MESODERMAL DEVELOPMENT

Establishment of the mesodermal germ layer is a process dependent on the integration of multiple transcriptional and signaling inputs. Here I investigate the role of the transcription factor FoxD3 in zebrafish mesodermal development. FoxD3 gain-of-function results in dorsal mesoderm expansion and body axis dorsalization. FoxD3 knockdown results in axial defects similar to Nodal loss-of-function, and was rescued by Nodal pathway activation. In Nodal mutants, FoxD3 did not rescue mesodermal or axial defects. Therefore, FoxD3 functions through the Nodal pathway and is essential for dorsal mesoderm formation. The FoxD3 mutant, sym1, previously described as a null mutation with neural crest defects, was reported to have no mesodermal or axial phenotypes. We find that Sym1 protein retains activity and induces mesodermal expansion and axial dorsalization. A subset of sym1 homozygotes display axial and mesodermal defects, and penetrance of these phenotypes is enhanced by FoxD3 knockdown in mutant embryos. Therefore, sym1 is a hypomorphic allele, and reduced FoxD3 function results in reduced cyclops expression and subsequent mesodermal and axial defects. The sym1 molecular lesion, a point deletion leading to a seven codon frameshift and premature termination, is predicted to be a truncated protein lacking part of the DNA-binding domain and an essential Groucho corepressor interaction domain (GEH). Strongly predicted to be functionally inactive, the hypomorphic character of sym1 suggested that a -1 translational frameshift may correct the reading frame and produce functional protein. Consistent with this hypothesis, mutation of the distal GEH ablated sym1 cDNA activity. Within the frameshift region are three rarely used codons predicted to cause ribosomal pausing and promote translational frameshifting. Conversion of these codons to highly used codons encoding the same residues rendered the sym1 cDNA inactive. Biochemical analyses confirm that a full length FoxD3 protein is produced from sym1 cDNA, but not when the rare codons are replaced. These results indicate that the null character of the sym1 mutation is suppressed by a novel translational frameshifting mechanism, and support the conclusion that FoxD3 is a Nodal-dependent regulator of zebrafish mesodermal development

The role of satisfaction and involvement in loyalty: Comparing residents and tourists

Satisfaction is commonly considered important in predicting future behavioral loyalty in tourism contexts. However, few attempts have been made to find out if the role of satisfaction intensifies involvement as a factor contributing to loyalty, and if the loyalty process for residents and tourists in the context of cultural and historic festivals is the same. Therefore, this study examined the loyalty process of residents (n=181) and tourists (n=227) who attended the Tulip Time Festival in Holland, Michigan, measuring the relationship between involvement, satisfaction, and likelihood of returning to the festival. The results showed that tourists\u27 loyalty is not assured by satisfaction and as such is different from that of residents. A more dynamic relationship between residents and tourists was suggested to increase tourists’ loyalty

Dimensional Changes of Upper Airway after Rapid Maxillary Expansion: A Prospective Cone-beam Computed Tomography Study

Introduction: The aim of this prospective study was to use cone-beam computed tomography to assess the dimensional changes of the upper airway in orthodontic patients with maxillary constriction treated by rapid maxillary expansion. Methods: Fourteen orthodontic patients (mean age, 12.9 years; range, 9.7-16 years) were recruited. The patients with posterior crossbite and constricted maxilla were treated with rapid maxillary expansion as the initial part of their comprehensive orthodontic treatments. Before and after rapid maxillary expansion conebeam computed tomography scans were taken to measure the retropalatal and retroglossal airway changes in terms of volume, and sagittal and cross-sectional areas. The transverse expansions by rapid maxillary expansion were assessed between the midlingual alveolar bone plates at the maxillary first molar and first premolar levels. The measurements of the before and after rapid maxillary expansion scans were compared by using paired t tests with the Bonferroni adjustment for multiple comparisons. Results: After rapid maxillary expansion, significant and equal amounts of 4.8 mm of expansion were observed at the first molar (P 5 0.0000) and the first premolar (P 5 0.0000) levels. The width increase at the first premolar level (20.0%) was significantly greater than that at the first molar level (15.0%) (P 5 0.035). As the primary outcome variable, the cross-sectional airway measured from the posterior nasal spine to basion level was the only parameter showing a significant increase of 99.4 mm2 (59.6%) after rapid maxillary expansion (P 5 0.0004). Conclusions: These results confirm the findings of previous studies of the effect of rapid maxillary expansion on the maxilla. Additionally, we found that only the cross-sectional area of the upper airway at the posterior nasal spine to basion level significantly gains a moderate increase after rapid maxillary expansion

Empowering Educators with Google\u27s Android App Inventor: An Online Workshop in Mobile App Design

In this report, the authors describe an introductory-level mobile app design workshop developed and offered over six weeks in Summer 2011. We also discuss the challenges and instructional implications derived from our experiences with this workshop

The Sustainable Child Development Index (SCDI) for countries

Despite the relevance of children in inheriting and shaping society, an index assessing sustainable development with a focus on children is missing. To tackle this gap, this study established the Sustainable Child Development Index (SCDI) by considering child development topics in the context of inter-generational equity and applying indicators with available statistical data on country level. The SCDI at present addresses health, education, safety, economic status and environmental aspects described by 25 indicators. By taking reference points derived from the targets of the Sustainable Development Goals (SDGs), the SCDI scores for the year 2015 were calculated for 138 countries and then classified into four sustainable child development levels (very high, high, medium and low). The results showed great regional inequality on the status of sustainable child development. European countries generally have better status of sustainable child development. By contrast, 90% of African and 76% of Asian countries were classified as countries with medium and low levels. Moreover, the comparison of the SCDI, the Human Development Index (HDI) and the Child Development Index (CDI) based on correlation analysis and 10-year (2006–2015) country rankings demonstrated that the SCDI can complement existing development indices to provide a more comprehensive evaluation of sustainable development.DFG, 325093850, Open Access Publizieren 2017 - 2018 / Technische Universität Berli