The Herschel Virgo Cluster Survey. VII. Dust in cluster dwarf elliptical galaxies

We use the science demonstration phase data of the Herschel Virgo Cluster Survey to search for dust emission of early-type dwarf galaxies in the central regions of the Virgo cluster as an alternative way of identifying the interstellar medium. We present the first possible far-infrared detection of cluster early-type dwarf galaxies: VCC781 and VCC951 are detected at the 10σ level in the SPIRE 250 μm image. Both detected galaxies have dust masses of the order of 10^5 M_⊙ and average dust temperatures ≈20 K. The detection rate (less than 1%) is quite high compared to the 1.7% detection rate for Hi emission, considering that dwarfs in the central regions are more Hi deficient. We conclude that the removal of interstellar dust from dwarf galaxies resulting from ram pressure stripping, harassment, or tidal effects must be as efficient as the removal of interstellar gas

The Effects of Children, Job Changes, and Employment Interruptions on Women’s Wages

In this dissertation, I build upon the literature examining the motherhood wage penalty. Although previous research has found that much of this penalty can be explained by differences between mothers and childless women in human capital acquisition, job experience, work hours, and unobserved characteristics, these reasons do not fully explain the penalty. The portion of the penalty that remains unexplained is often attributed to some combination of discrimination against women by employers and lower work effort among mothers. In this dissertation, I examine another plausible mechanism: I consider the role that job changes and employment exits play in creating this penalty. In doing this, I draw on economic theories of job mobility that posit job changes play an important role in shaping workers’ wage trajectories. I also draw on signaling theory, which argues the reason workers leave their job and spend time in non-employment matters in shaping workers’ future wages. I use panel data from the National Longitudinal Survey of Youth, 1979 (NLSY79). This dataset follows a cohort of nearly 6,000 women who entered the labor market in the late 1970s and early 1980s, a time during which changing employers was becoming increasingly common. I use data from surveys conducted between 1979-2010 (the most recent year of data available). I apply event history and fixed effects models to examine how children shape women’s job changes and employment exits, and how these events, in turn, shape women’s wages. Throughout this dissertation, I examine how motherhood intersects with race/ethnicity, spouse characteristics, birth timing, and education to shape women’s labor market decisions and wage outcomes. I found motherhood reduces the hazard that women will make the types of non-family voluntary job changes that often result in wage gains. I also found that different patterns of changing jobs and exiting the labor market contributes to roughly twenty percent of the unexplained motherhood wage penalty, and moreover, these differences help to explain why the wage penalty is largest for women who bear children early in adulthood. Finally, in examining the different reasons women spend time in non-employment, I found family-related interruptions are associated with larger short-term wage penalties compared to interruptions following a layoff, but the penalties for family-related interruptions persist over the long-term only among highly educated women

DustKING - the story continues: dust attenuation in NGC628

Dust attenuation is a crucial but highly uncertain parameter that hampers the determination of intrinsic galaxy properties, such as stellar masses, star formation rates and star formation histories. The shape of the dust attenuation law is not expected to be uniform between galaxies, nor within a galaxy. Our DustKING project was introduced at the first BINA workshop in 2016 and aims to study the variations of dust attenuation curves in nearby galaxies. At the second BINA workshop in 2018, I presented the results of our pilot study for the spiral galaxy NGC628. We find that the average attenuation law of this galaxy is characterised by a MW-like bump and a steep UV slope. Furthermore, we observe intriguing variations within the galaxy, with regions of high $A_V$ exhibiting a shallower attenuation curve. Finally, we discuss how our work might benefit from data taken with the UVIT from the Indian AstroSat mission.Comment: 8 pages, 6 figures, Proceedings paper of the second Belgo-Indian Network for Astronomy & astrophysics (BINA) workshop, accepted for publication in the Bulletin de la Soci\'et\'e Royale des Sciences de Li\`eg

DustKING, the story continues : dust attenuation in NGC 628

Dust attenuation is a crucial but highly uncertain parameter that hampers the determination of in- trinsic galaxy properties, such as stellar masses, star formation rates and star formation histories. The shape of the dust attenuation law is not expected to be uniform between galaxies, nor within a galaxy. Our DustKING project was introduced at the first BINA workshop in 2016 and aims to study the variations of dust attenuation curves in nearby galaxies. At the second BINA workshop in 2018, I presented the results of our pilot study for the spiral galaxy NGC 628. We find that the average attenuation law of this galaxy is characterised by a MW-like bump and a steep UV slope. Furthermore, we observe intriguing variations within the galaxy, with regions of high AV exhibiting a shallower attenuation curve. Finally, we discuss how our work might benefit from data taken with the UVIT from the Indian AstroSat mission

Forest Fragmentation Patterns in Maine Watersheds and Prediction of Visible Crown Diameter in Recent Undisturbed Forest

Extensive harvesting practices coupled with major ownership change have led to increasing fragmentation of Maine’s forest, a reduction from larger, contiguous mature forest patches into smaller patches. Using Landsat Thematic Mapper (TM) - based forest cover and change maps (1991-2007), fragmentation metrics, and Principal Components Analysis (PCA), this study determined the extent and configuration of forest fragmentation within three ecoregions and 186 level 5 watersheds throughout the state of Maine. Forests in the Northeastern ecoregion had higher harvest rates and more interspersed patches of undisturbed forest. Forests in the South-Central ecoregion are composed of more, smaller patches than their Northeastern and Western counterparts but had the highest proportion of undisturbed forest at the end of the study period. The cover type PCA indicated that softwood has been the most harvested cover type; mixedwood and hardwood were more prevalent in the residual forest stands. Softwood forests showed a marked decrease in size and area in unharvested forests of the Northeastern and Western ecoregions. The Western ecoregion consisted of small patches of hardwood forest that were closer together, and hardwood forest represented a greater proportion of the landscape. Softwood forest patch shapes were more complex in the South-Central ecoregion. This research provides a numerical assessment of the spatially explicit effects of the 1991-2007 harvesting legacy on the landscape (watershed level) composition of Maine. With Maine’s northern forest being fragmented and patch size decreasing over time, maintaining a distribution of larger trees may be ecologically valuable. There are no spatially explicit maps for Maine showing the distribution of old growth or large diameter forest and ground data is lacking. Therefore, methods using multiple sources of remotely sensed data, topographic and site index data were combined in a modeling application to predict visible crown diameter (VCD) as a proxy for tree size in recent undisturbed forest (RUF), stands that were not harvested between 1972 and 2007. Change detection maps derived from Landsat TM imagery, raw Landsat TM imagery, two sources of aerial photography, and ancillary data were used as input into a random forests model. Results indicated differences in VCD ranges and importance of predictive variables between softwood, mixedwood, and hardwood forest cover. Recent undisturbed softwood and mixedwood VCD decreased with increasing site elevation and slope. Softwood VCD increased with increasing spectral values of Landsat TM 1, the Normalized Difference Moisture Index and Tasseled Cap wetness, suggesting sensitivity to moisture or shadowing in the canopy. Recent undisturbed hardwood forests were found on the best sites at low elevations. Hardwood VCD responded to spectral variables, especially Tasseled Cap brightness, and the Landsat TM reflected infrared wavebands 4, 5, and 7. This research is repeatable in other regions, provided there is access to historical aerial photography and reliable map information or ground data that could verify the presence of undisturbed forest at earlier dates

Creating a Cycle of Continuous Improvement Through Instructional Rounds

Instructional Rounds is a continuous improvement strategy that focuses on the technical core of educational systems as well as educators collaborating side-by-side. Concentrating on collective learning, this process only makes sense within an overall strategy of improvement. This case study examined the Instructional Rounds process in a northern Michigan school district. Pressure points identified included a culture of distrust, an unclear definition of learner outcomes and effective teaching, and a status quo view of improvement. Supportive strategies for change were identified and continue to be implemented as part of the district’s continuous improvement strateg

Economic Engagement of Mothers: Entrepreneurship, Employment, and the Motherhood Wage Penalty

The economic value women bring to their own households and to the broader economy is well-documented. In fact, nearly all of the economic gains that have occurred among middle class families since 1970 have come from the increased earnings of women. Mothers make substantial contributions to the finances of many families and households. In 2018, nearly half of the more than 30 million families with children under 18 in the United States had either a single mother or a married mother contributing at least 40% of a couple's joint earnings.Despite the importance of mothers' economic contributions, the broader economy fails to support mothers in a variety of ways. The costs of raising children fall largely on families – and disproportionately on mothers. In addition to the lack of support for combining careers with caregiving, mothers face a motherhood wage penalty, which accounts for much of the gender wage gap. Even entrepreneurship, an economic activity that can potentially offer more autonomy and flexibility, is made more difficult for mothers by child care challenges and barriers to entrepreneurship for women more broadly.Why is motherhood undervalued and unsupported economically?What does entrepreneurship support mean for entrepreneurs who are mothers? And how can we support mothers' access to opportunities to engage in the economy – and ease their access to opportunity through entrepreneurship

An examination of the relationship between the generation a teacher is born into, teaching style, and high school student engagement

Educators across America are attempting to prepare students for a world of rapid change, including globalization and the move from industrialization to the Age of Information (Marx, 2006). Dynamics of change include teachers, who encompass a wide range of generations and experiences (Marx, 2006). Each generation includes a set of value and belief systems (Oblinger, 2003). Each generation has been engaged in their learning experiences in differing ways. The primary purposes of this study were to determine if there were relationships between teacher generation and teaching style, teacher generation and student engagement, and teaching style and student engagement. A survey of 53 teachers in five large Michigan high schools identified teachers’ generations and analyzed their preponderance towards five different teaching styles. Close to 3000 ninth and tenth grade students in the same high schools were also surveyed regarding nine different constructs related to student engagement. A quantitative, non-experimental, correlational design determined relationships using the Pearson Product Moment statistical test. Five low relationships were found – teacher generation and the delegator teaching style, facilitator teaching style and three constructs of student engagement, and the delegator teaching style and two-student engagement constructs. Further research into these two teaching styles and student engagement constructs should be conducted. The more we learn about effective teaching practices and how they relate to the engagement of students, the more effective we can be in our teacher professional development and continuous learning programs