The lamp-post geometry is often used to model X-ray data of accreting black holes. Despite its simple assumptions, it has proven to be powerful in inferring fundamental black hole properties such as the spin. Early results of X-ray reverberations showed support for such a simple picture, though wind-reverberation models have also been shown to explain the observed delays. Here, we analyze new and old XMM-Newton observations of the variable Seyfert-1 galaxy NGC 5506 to test these models. The source shows an emission line feature around 6.7 keV that is delayed relative to harder and softer energy bands. The spectral feature can be modeled with either a weakly relativistic disk line or by scattering in distant material. By modeling both the spectral and timing signatures, we find that the reflection fraction needed to explain the lags is larger than observed in the time-averaged spectrum, ruling out both a static lamp-post and simple wind reverberation models.Sgr A*, the supermassive black hole (SMBH) at the center of our Milky Way Galaxy, is known to be a variable source of X-ray, near-infrared (NIR), and submillimeter radiation and therefore a prime candidate to study the electromagnetic radiation generated by mass accretion flow onto a black hole and/or a related jet. PGE2 chemical structure Disentangling the power source and emission mechanisms of this variability is a central challenge to our understanding of accretion flows around SMBHs. Simultaneous multiwavelength observations of the flux variations and their time correlations can play an important role in obtaining a better understanding of possible emission mechanisms and their origin. This paper presents observations of two flares that both apparently violate the previously established patterns in the relative timing of submillimeter/NIR/X-ray flares from Sgr A*. One of these events provides the first evidence of coeval structure between NIR and submillimeter flux increases, while the second event is the first example of the sequence of submillimeter/X-ray/NIR flux increases all occurring within ~1 hr. Each of these two events appears to upend assumptions that have been the basis of some analytic models of flaring in Sgr A*. However, it cannot be ruled out that these events, even though unusual, were just coincidental. These observations demonstrate that we do not fully understand the origin of the multiwavelength variability of Sgr A* and show that there is a continued and important need for long-term, coordinated, and precise multiwavelength observations of Sgr A* to characterize the full range of variability behavior.
This paper provides an overview of crown and root morphology in Eskimo-Aleut populations of the American Arctic. For context, Eskimo-Aleut dental variation is compared to closely related American Indians and distantly related Europeans.
The characterization of dental trait frequency variation is based on observations made on approximately 10,000 dentitions scored by the late Christy G. Turner II and the author. Sixteen crown and five root traits were scored following the conventions outlined in the Arizona State University Dental Anthropology System.
Of the 21 dental traits considered, only three showed slight differences among Eskimo-Aleuts, American Indians, and Europeans (UM1 cusp 5, LM2 groove pattern, LM2 root number). For the remaining traits, there was typically a dramatic contrast between the two New World populations and Europeans. While generally similar, Eskimo-Aleuts and American Indians showed differences in UI1 winging, shoveling, and double shoveling, UM1 Carabelli trait, 2-cusped UM2, 3-rooted UM2, and especially 3-rooted LM1.
The differences between the three groups are likely a product of genetic drift and founder effect although recent work on the EDAR V370A allele suggests some dental variables like shoveling and lower molar cusp number may indirectly reflect natural selection operating on other variables influenced by this allele.
Tooth Crown; Tooth Root; Alaska Natives; North American Indians; European Continental Ancestry Group.
Tooth Crown; Tooth Root; Alaska Natives; North American Indians; European Continental Ancestry Group.
To analyze a bibliometric profile of scientific production published in Acta Stomatologica Croatica (ASCRO).
Scientific papers published from March 2009 to December 2018 were analyzed. Information on the year of publication was collected by four trained examiners. Dentistry area, study type and design, data analysis method, presence of randomization, number of authors and corresponding author affiliation were investigated. Data were analyzed using descriptive statistics.
A total of 328 articles were evaluated, with a predominance of research in the field of Dental Materials (16.5%), with original article being the most frequent (74.1%). Observational studies accounted for 52.4%, using inferential statistics (83.2%) and non-randomized experimental studies (66.1%). Cross-sectional studies were more common in areas of Behavioral, Epidemiologic & Health Services Research (86.3%), case reports in Craniofacial Biology (54.0%) and Oral Health Research (53.1%), while
studies were more common in the areas of Dental Materials (90.7%), Microbiology / Immunology (70.0%) and Cariology Research (66.7%). Most articles were written by four authors (24.1%), while foreign affiliation was observed in 53.0% of studies.
The profile of ASCRO scientific production shows a predominance of original studies carried out in the areas of Dental Materials and Behavioral, Epidemiologic & Health Services Research, with growing participation of foreign researchers.
The profile of ASCRO scientific production shows a predominance of original studies carried out in the areas of Dental Materials and Behavioral, Epidemiologic & Health Services Research, with growing participation of foreign researchers.
To investigate and compare the factors that motivated students to study dentistry in countries with similar background (Albania, Croatia and the Republic of Northern Macedonia) and to assess whether or not their motivation changed during time.
In 2014/2015, cross-sectional studies were conducted in state funded dental schools in Tirana (Albania), Zagreb (Croatia) and Skopje (Macedonia) to assess student views on their career motivation. All dental students from the first, third and final years of study were invited to participate. The participation was voluntary and anonymous. A five-item questionnaire was translated into languages of the participating countries. Ethics approval was granted by the Ethics Committee of the University of Saints Cyril and Methodius, Skopje. The Chi square test was used to test if there were statistically significant differences in answers between students in 3 countries, furthermore between years of the study.
The total number of respondents was 739 (319 in Tirana, 211 in Zagreb and 208 in Skopje) The differences in the answers between the first-year students from all three countries were statistically significant (χ
=82.PGE2 chemical structure
Top comments (0)