Serita Frey Professor of Natural Resources and the Environment (COLSA) travels to Argentina

The Center for International Education provided partial financial support for my sabbatical in Argentina during fall 2015. The specific goals of my trip to Argentina were to (1) visit and interact with a research group at the University of Buenos Aires, (2) explore potential research sites in the Patagonian steppe in southern Argentina, and (3) write several manuscripts and proposals

Blurring The Border: Examining Strain Among Latino Youth Using Latinx General Strain Theory (LGST)

Criminological research indicates the Latinx population disproportionality commits crime. Latinx youth represent nearly 30% of the juvenile justice system (State of Americas Children, 2020). In 2008, Pérez and colleagues examined ethnic-specific differences that affect Latinx in the strain delinquency relationship. The authors used Latinx General Strain Theory (LGST) to identify the distinctive strains Latinx experienced as a result of their unique socio-cultural and ethnic experiences. However, the impact police perceptions have on Latinx delinquency has yet to be fully identified (Isom Scott et al., 2021; Isom Scott et al., 2020; Thaxton & Agnew, 2018). This dissertation examined LGST by assessing the impact ethnic-specific strains, police perceptions, and traditional strains had on Latinx delinquency and status offenses. This study utilized four research questions: 1: Does acculturation strain impact the likelihood of Latinx youth committing status offenses and delinquency; 2: Does negative perceptions of police impact the likelihood of Latinx youth committing status offenses iv and delinquency; 3: Do negative emotions impact the likelihood of Latinx youth committing status offenses and delinquency; 4: Do traditional GST strains impact the likelihood of Latinx youth committing status offenses and delinquency. Utilizing the Gang Resistance Education Training Data (GREAT) set. This study examined multiple waves using negative binomial regression analysis to assess the impact traditionally, and ethnic-specific strains have on Latinx youth committing delinquency and status offenses. Results suggest Latinx youth born in the United States (e.g., acculturated) were more likely to report delinquency compared to Latinx youth born in another country. Having lower feelings of ethnic identity increased overall delinquency, and Latinx youth who reported negative perceptions of police also increased delinquency. Future research should examine more measures of police strain or police racial discrimination in the Latinx strain delinquency relationship

An exploration of the experiences of Zimbabwean women informal cross-border traders at the Zimbabwean/South African BeitBridge border post

Includes bibliographical references.Much research on economically-enforced migration between Zimbabwe and South Africa locates women as partners of men, rather than as economic agents in their own terms. Research on cross-border trade, however, has theorized that gender dynamics may empower women traders as they learn to negotiate new business networks and as they develop economic independence; a different perspective on gender dynamics suggests that far from empowerment, women cross border-traders face particular abuse and harassment. This research worked with eleven Zimbabwean cross border traders to explore the theoretical tensions between notions of ‘empowerment’ and notions of ‘disadvantage’ arising from the traders’ experiences. The study concentrated in particular on the traders’ representation of their experiences at the Zimbabwe/South Africa Beitbridge border post crossing point. Analysing the material qualitatively, the dissertation argues that while gender dynamics can be seen to afford the traders both opportunities and great challenges, the traders’ representations of the interplay of official corruption and the impact of economic pressure on all border-players reveal the border-post itself as a complex site of micro-negotiations whereby survival becomes the ‘business’ itself

Migrant Misconceptions: A Review of Literature on National Heritage, Immigration Status, and Juvenile Offending

In 2020, the Pew Research Center reported over 40 million Latinx adults are immigrants and nearly 23% are U.S.-born adult children of immigrant parents. Some rhetoric that surrounds immigration is indicative of crime, criminals, and the need to build a wall to protect the U.S. border from migrant crossing. In the U.S., immigration policies apply a \u27securitized\u27 approach to criminal law enforcement involving Latinos. However, criminological literature indicates immigrants do not pose any more of a threat towards crime than a natural-born citizen. Continued research should be completed to better understand differences among immigrant youth compared to native-born Latino youth

Engineering management of large scale systems

The organization of high technology and engineering problem solving, has given rise to an emerging concept. Reasoning principles for integrating traditional engineering problem solving with system theory, management sciences, behavioral decision theory, and planning and design approaches can be incorporated into a methodological approach to solving problems with a long range perspective. Long range planning has a great potential to improve productivity by using a systematic and organized approach. Thus, efficiency and cost effectiveness are the driving forces in promoting the organization of engineering problems. Aspects of systems engineering that provide an understanding of management of large scale systems are broadly covered here. Due to the focus and application of research, other significant factors (e.g., human behavior, decision making, etc.) are not emphasized but are considered

Improved methods for phylogenetics

textPhylogenetics is the study of evolutionary relationships. It is a scientific endeavour to discover history, and it is not easy. Massive amounts of data together with computationally difficult optimization problems mean that heuristics are prevalent, and ever better techniques are sought. New approaches are valuable if they are more accurate, but are considered even more so if they are faster than pre-existing methods. Improvements to existing algorithms, whether in terms of space requirements, or faster running times, are also worthwhile. This dissertation explores three new techniques, each of which is valuable according to the previous definitions. The first contribution is TASPI, a system for storing collections of phylogenetic trees, and performing post-tree analyses. TASPI stores collections of trees more compactly than the previous method, and this compact structure lends itself to post-tree analyses. This results in the ability to compute strict and majority consensus trees faster than common alternatives. As an added benefit, TASPI is written in ACL2, which allows properties of the algorithms and data structures to be formally verified. The second contribution is an improved method to generate phylogenetic trees. A common methodology involves two steps, first estimating a Multiple Sequence Alignment (MSA), and then estimating a tree using that MSA. This method changes the way in which the MSA is estimated, and this leads to improved accuracy of the resultant trees. Also, in some cases, the time required is also reduced. The third contribution is BLuTGEN, a method by which a phylogenetic tree is estimated from sequence data, but without ever generating an MSA for the full dataset. BLuTGEN is as accurate as one of the best published tree estimation techniques (SATé), but takes a novel approach which allows it to be applied to much larger datasets.Computer Science

Principal component analysis and singular spectrum analysis of ULF geomagnetic data associated with earthquakes

International audienceIn order to extract any ULF signature associated with earthquakes, the principal component analysis (PCA) and singular spectral analysis (SSA) have been performed to investigate the possibility of discrimination of signals from different sources (geomagnetic variation, artificial noise, and the other sources (earthquake-related ULF emissions)). We adopt PCA to the time series data observed at closely separated stations, Seikoshi (SKS), Mochikoshi (MCK), and Kamo (KAM). In order to remove the most intense signal like the first principal component, we make the differential data sets of filtered 0.01Hz SKS-KAM and MCK-KAM in NS component and 0.01 Hz band. The major findings are as follows. (1) It is important to apply principal component analysis and singular spectral analysis simultaneously. SSA gives the structure of signals and the number of sensors for PCA is estimated. This makes the results convincing. (2) There is a significant advantage using PCA with differential data sets of filtered (0.01 Hz band) SKS-KAM and MCK-KAM in NS component for removing the most intense signal like global variation (solar-terrestrial interaction). This provides that the anomalous changes in the second principal component appeared more sharply. And the contribution of the second principal component is 20?40%. It is large enough to prove mathematical accuracy of the signal. Further application is required to accumulate events. These facts demonstrate the possibility of monitoring the crustal activity by using the PCA and SSA

Seasonal dynamics of soil respiration and nitrogen mineralization in chronically warmed and fertilized soils

Although numerous studies have examined the individual effects of increased temperatures and N deposition on soil biogeochemical cycling, few have considered how these disturbances interact to impact soil C and N dynamics. Likewise, many have not assessed season-specific responses to warming and N inputs despite seasonal variability in soil processes. We studied interactions among season, warming, and N additions on soil respiration and N mineralization at the Soil Warming × Nitrogen Addition Study at the Harvard Forest. Of particular interest were wintertime fluxes of C and N typically excluded from investigations of soils and global change. Soils were warmed to 5°C above ambient, and N was applied at a rate of 5 g m−2 y−1. Soil respiration and N mineralization were sampled over two years between 2007 and 2009 and showed strong seasonal patterns that mirrored changes in soil temperature. Winter fluxes of C and N contributed between 2 and 17% to the total annual flux. Net N mineralization increased in response to the experimental manipulations across all seasons, and was 8% higher in fertilized plots and 83% higher in warmed plots over the duration of the study. Soil respiration showed a more season-specific response. Nitrogen additions enhanced soil respiration by 14%, but this increase was significant only in summer and fall. Likewise, warming increased soil respiration by 44% over the whole study period, but the effect of warming was most pronounced in spring and fall. The only interaction between warming × N additions took place in autumn, when N availability likely diminished the positive effect of warming on soil respiration. Our results suggest that winter measurements of C and N are necessary to accurately describe winter biogeochemical processes. In addition, season-specific responses to the experimental treatments suggest that some components of the belowground community may be more susceptible to warming and N additions than others. Seasonal changes in the abiotic environment may have also interacted with the experimental manipulations to evoke biogeochemical responses at certain times of year