Examining Differences in Housing Voucher Law Application im Cool and DuPage Counties

This study examines the experiences of families with active involvement in open cases with the Illinois Department of Children and Family Services (DCFS) within a Housing Advocacy Program (HAP) at La Casa Norte in Chicago, Illinois. Housing advocates in this program work with clients in the city of Chicago and suburban Cook County, as well as DuPage County. This program focuses on assessing the needs of families with open DCFS cases who are nearing completion of a mandated program, with housing that meets DCFS guidelines and requirements being one of the final steps towards case closure. HAP case managers educate clients on conducting housing searches, as well as how to properly communicate with landlords, identifying proper details to look for in rental units, and overall navigation of both the affordable housing and market rate rental landscape. Many clients present with compounding issues outside of being unstably housed, such as lack of employment and financial resources, prior criminal involvement, a history of surviving domestic violence, and physical or mental disability. These factors often complicate and present more pressing issues for case managers to address before housing can be approached. Further complicating matters when working with this population is not only the lack of affordable housing vouchers available for those in need, but the fact that applications of housing laws set by the Department of Housing and Urban Development (HUD) are interpreted differently by Cook and DuPage counties. This study aims to identify if program participants in DuPage county experience higher levels of discrimination based on housing voucher status than participants in the city of Chicago and suburban Cook County, and what shared characteristics this population holds. This study looks at socio-economic factors as well as social factors in relation to outcomes for program participants in trying to understand their experience

Suppressed eddy driving during southward excursions of the North Atlantic jet on synoptic to seasonal time scales

Jet streams shape midlatitude weather and climate. The North Atlantic jet is mainly eddy‐driven, with frequent north–south excursions on synoptic time scales arising from eddy forcings and feedbacks. There are, however, special periods during which the underlying dynamics appear to change—for example, winter 2009/2010, when the jet was persistently southward‐shifted, extremely zonal, and more thermally driven. This study shows evidence that the southern jet configuration exhibits altered dynamical behavior involving a shift in the balance of thermal and eddy‐driving processes, independent of timescale. Specifically, southern jets exhibit weaker eddy feedbacks and are associated with enhanced heating in the tropical Pacific. During winter 2009/2010, a remarkably frequent (66 days out of the 90‐day winter season) and persistent southern jet shaped the unusual seasonal signature. These results bridge the synoptic and climate perspectives of jet variability, with potential to help understand and reduce biases in regional climate variability as simulated by models.publishedVersio

Internal Variability in Projections of Twenty-First-Century Arctic Sea Ice Loss: Role of the Large-Scale Atmospheric Circulation

Internal variability in twenty-first-century summer Arctic sea ice loss and its relationship to the large-scale atmospheric circulation is investigated in a 39-member Community Climate System Model, version 3 (CCSM3) ensemble for the period 2000–61. Each member is subject to an identical greenhouse gas emissions scenario and differs only in the atmospheric model component’s initial condition. September Arctic sea ice extent trends during 2020–59 range from -2.0 x 10⁶ to -5.7 x 10⁶ km² across the 39 ensemble members, indicating a substantial role for internal variability in future Arctic sea ice loss projections. A similar nearly threefold range (from -7.0 x 10³ to -19 x 10³ km³) is found for summer sea ice volume trends. Higher rates of summer Arctic sea ice loss in CCSM3 are associated with enhanced transpolar drift and Fram Strait ice export driven by surface wind and sea level pressure patterns. Over the Arctic, the covarying atmospheric circulation patterns resemble the so-called Arctic dipole, with maximum amplitude between April and July. Outside the Arctic, an atmospheric Rossby wave train over the Pacific sector is associated with internal ice loss variability. Interannual covariability patterns between sea ice and atmospheric circulation are similar to those based on trends, suggesting that similar processes govern internal variability over a broad range of time scales. Interannual patterns of CCSM3 ice–atmosphere covariability compare well with those in nature and in the newer CCSM4 version of the model, lending confidence to the results. Atmospheric teleconnection patterns in CCSM3 suggest that the tropical Pacific modulates Arctic sea ice variability via the aforementioned Rossby wave train. Large ensembles with other coupled models are needed to corroborate these CCSM3-based findings.Keywords: Climate models, Atmospheric circulation, Sea ice, Climate variability, Atmosphere-ocean interaction, Climate chang

Abrupt Ice Age Shifts in Southern Westerlies and Antarctic Climate Forced from the North

The Southern Hemisphere (SH) mid-latitude westerly winds play a central role in the global climate system via Southern Ocean upwelling, carbon exchange with the deep ocean, Agulhas Leakage, and Antarctic ice sheet stability. Meridional shifts in the SH westerlies have been hypothesized in response to abrupt North Atlantic Dansgaard-Oeschger (DO) climatic events of the last ice age, in parallel with the well-documented shifts of the intertropical convergence zone. Shifting moisture pathways to West Antarctica are consistent with this view, but may represent a Pacific teleconnection pattern. The full SH atmospheric-circulation response to the DO cycle, as well as its impact on Antarctic temperature, have so far remained unclear. Here we use five volcanically-synchronized ice cores to show that the Antarctic temperature response to the DO cycle can be understood as the superposition of two modes: a spatially homogeneous oceanic “bipolar seesaw” mode that lags Northern Hemisphere (NH) climate by about 200 years, and a spatially heterogeneous atmospheric mode that is synchronous with NH abrupt events. Temperature anomalies of the atmospheric mode are similar to those associated with present-day Southern Annular Mode (SAM) variability, rather than the Pacific South America (PSA) pattern. Moreover, deuterium excess records suggest a zonally coherent migration of the SH westerlies over all ocean basins in phase with NH climate. Our work provides a simple conceptual framework for understanding the circum-Antarctic temperature response to abrupt NH climate change. We provide observational evidence for abrupt shifts in the SH westerlies, with ramifications for global ocean circulation and atmospheric CO₂. These coupled changes highlight the necessity of a global, rather than a purely North Atlantic, perspective on the DO cycle

Holding it together: rapid evolution and positive selection in the synaptonemal complex of Drosophila

Background The synaptonemal complex (SC) is a highly conserved meiotic structure that functions to pair homologs and facilitate meiotic recombination in most eukaryotes. Five Drosophila SC proteins have been identified and localized within the complex: C(3)G, C(2)M, CONA, ORD, and the newly identified Corolla. The SC is required for meiotic recombination in Drosophila and absence of these proteins leads to reduced crossing over and chromosomal nondisjunction. Despite the conserved nature of the SC and the key role that these five proteins have in meiosis in D. melanogaster, they display little apparent sequence conservation outside the genus. To identify factors that explain this lack of apparent conservation, we performed a molecular evolutionary analysis of these genes across the Drosophila genus. Results For the five SC components, gene sequence similarity declines rapidly with increasing phylogenetic distance and only ORD and C(2)M are identifiable outside of the Drosophila genus. SC gene sequences have a higher dN/dS (ω) rate ratio than the genome wide average and this can in part be explained by the action of positive selection in almost every SC component. Across the genus, there is significant variation in ω for each protein. It further appears that ω estimates for the five SC components are in accordance with their physical position within the SC. Components interacting with chromatin evolve slowest and components comprising the central elements evolve the most rapidly. Finally, using population genetic approaches, we demonstrate that positive selection on SC components is ongoing. Conclusions SC components within Drosophila show little apparent sequence homology to those identified in other model organisms due to their rapid evolution. We propose that the Drosophila SC is evolving rapidly due to two combined effects. First, we propose that a high rate of evolution can be partly explained by low purifying selection on protein components whose function is to simply hold chromosomes together. We also propose that positive selection in the SC is driven by its sex-specificity combined with its role in facilitating both recombination and centromere clustering in the face of recurrent bouts of drive in female meiosis

Storm track variability and interaction with the background flow on daily, interannual and climate change time scales

Thesis (Ph. D.)--University of Washington, 2007.Variability in the observed Northern and Southern Hemisphere storm tracks is dominated by "pulsing" and "latitudinally shifting" modes in sectors of each hemisphere. These modes are useful simplifications of the full complexity of storm track variability and are ubiquitous in different variables, at different levels in the troposphere and on in the storm track variability on different time scales. Variability associated with the pulsing mode almost always accounts for a large fraction of the variance than the latitudinally shifting mode, but the latitudinally shifting mode is more strongly associated with persistent anomalies in the background flow and with dominant climate variability patterns. At monthly time scales, both the pulsing and latitudinally shifting modes of storm track variability are associated with zonal wind anomalies consistent with eddy-forced acceleration of the zonal wind. At daily time scales, the pulsing mode is associated with an evolution culminating in zonal wind anomalies and eddy activity that shift poleward over time. In model simulations associated with climate change time scales of variability, measures of storm track intensity near the level of the jet indicate suppressed eddy amplitude in cold climates relative to warm climates, whereas measures in the lower troposphere indicate an enhancement of eddy activity. Investigating the seasonality and dynamics of these offsetting tendencies between upper and lower tropospheric levels and the relationship between the dominant modes of storm track variability and the background flow remain as motivations for future work

Changes in atmospheric variability in a glacial climate and the impacts on proxy data: a model intercomparison

Using four different climate models, we investigate sea level pressure variability in the extratropical North Atlantic in the preindustrial climate (1750 AD) and at the Last Glacial Maximum (LGM, 21 kyrs before present) in order to understand how changes in atmospheric circulation can affect signals recorded in climate proxies. In general, the models exhibit a significant reduction in interannual variance of sea level pressure at the LGM compared to pre-industrial simulations and this reduction is concentrated in winter. For the preindustrial climate, all models feature a similar leading mode of sea level pressure variability that resembles the leading mode of variability in the instrumental record: the North Atlantic Oscillation (NAO). In contrast, the leading mode of sea level pressure variability at the LGM is model dependent, but in each model different from that in the preindustrial climate. In each model, the leading (NAO-like) mode of variability explains a smaller fraction of the variance and also less absolute variance at the LGM than in the preindustrial climate. The models show that the relationship between atmospheric variability and surface climate (temperature and precipitation) variability change in different climates. Results are model-specific, but indicate that proxy signals at the LGM may be misinterpreted if changes in the spatial pattern and seasonality of surface climate variability are not taken into account