Mapping the 13CO/C18O abundance ratio in the massive star forming region G29.96-0.02

Estimating molecular abundances ratios from the direct measurement of the emission of the molecules towards a variety of interstellar environments is indeed very useful to advance in our understanding of the chemical evolution of the Galaxy, and hence of the physical processes related to the chemistry. It is necessary to increase the sample of molecular clouds, located at different distances, in which the behavior of molecular abundance ratios, such as the 13CO/C18O ratio (X), is studied in detail. We selected the well-studied high-mass star-forming region G29.96-0.02, located at a distance of about 6.2 kpc, which is an ideal laboratory to perform this kind of studies. To study the X towards this region it was used 12CO J=3-2 data obtained from COHRS, 13CO and C18O J=3-2 data from CHIMPS, and 13CO and C18O J=2-1 data retrieved from the CDS database (observed with the IRAM 30m telescope). The distribution of column densities and X throughout the molecular cloud was studied based on LTE and non-LTE methods. Values of X between 1.5 to 10.5, with an average of 5, were found, showing that, besides the dependency between X and the galactocentric distance, the local physical conditions may strongly affect this abundance ratio. We found that correlating the X map with the location of the ionized gas and dark clouds allows us to suggest in which regions the far-UV radiation stalls in dense gaseous components, and in which ones it escapes and selectively photodissociates the C18O isotope. The non-LTE analysis shows that the molecular gas has very different physical conditions, not only spatially across the cloud, but also along the line of sight. This kind of studies may represent a tool to indirectly estimate (from molecular lines observations) the degree of photodissociation in molecular clouds, which is indeed useful to study the chemistry in the interstellar medium.Comment: Accepted in A&A (July 10, 2018

Attrition of ESL foreign-born Hispanic students at CSN

This qualitative naturalistic study examined the retention barriers for foreign-born Hispanic English as Second Language (ESL) students that dropped out of the College of Southern Nevada (CSN) ESL for-credit program and the need for services they perceived would have helped them succeed. The participants for this study were foreign-born Hispanics who were taking ESL 110B, ESL 111B and ESL 120B (levels 1, 2, and 3) during the 2005-2006 academic year and have since dropped out. The main focus of the study was on institutional and social factors that affected the retention rate of this population at CSN. Four in-depth interviews were conducted to better understand those factors. The findings show the need for bilingual instructors and bilingual support service staff. A major factor which affected interviewees\u27 non-continuation in the ESL for-credit program was their lack of knowledge about the availability of support services

The Right Match: A Strong Principal in Every Public School

This report has one central premise: Keeping great principals starts with hiring the right principal. Even as Chicago fights to retain principals long enough to make student learning and school culture gains more permanent, we must recognize some principal attrition is inevitable.More than 70,000 students started the 2016-17 school year with a new principal, and at least 60 schools will need a new principal each year for the foreseeable future. The stakes are high: No great public school exists without great leadership. In fact, variation in principal quality accounts for about 25 percent of a school's total impact on student learning. Yet, more than four out of every 10 public school principals in Chicago leave before they begin their fifth year. To keep great principals, we have to make the right match from the start

SUSIG: an on-line signature database, associated protocols and benchmark results

We present a new online signature database (SUSIG). The database consists of two parts that are collected using different pressure-sensitive tablets ( one with and the other without an LCD display). A total of 100 people contributed to each part, resulting in a database of more than 3,000 genuine signatures and 2,000 skilled forgeries. The genuine signatures in the database are real signatures of the contributors. In collecting skilled forgeries, forgers were shown the signing process on the monitor and were given a chance to practice. Furthermore, for a subset of the forgeries ( highly skilled forgeries), this animation was mapped onto the LCD screen of the tablet so that the forgers could trace over the mapped signature. Forgers in this group were also informed of how close they were to the reference signature, so that they could improve their forgery quality. We describe the signature acquisition process and several verification protocols for this database. We also report the performance of a state-of-the-art signature verification system using the associated protocols. The results show that the highly skilled forgery set is significantly more difficult compared to the skilled forgery set, providing researchers with challenging forgeries. The database is available through http://icproxy.sabanciuniv.edu:215