Suburban Poverty and Racial Segregation

Over the past thirty years, increasing numbers of low-income people live in suburbs in the United States, with an increased proportion of racial and ethnic minorities among them (Covington, Freeman, & Stoll, 2011; Frey, 2011; Howell & Timberlake, 2014; Puentes & Warren, 2006). In urban areas, increases in poverty rates have been marked by increases in racial and ethnic segregation among people living in poverty (Logan & Stults, 2010; Massey, 1990; Orfield & Luce, 2012). What is less clear from the research on suburban poverty is how much racial segregation exists. For example, some research indicates that there is more segregation among black people in the suburbs than in urban areas (Darden & Kamel, 2002) whereas other research finds that black people in the suburbs are less likely to live in segregated communities than black people in urban areas (Alba, Logan, & Stults, 2000). This paper presents findings from a new set analyses, using data from the U.S. Census Bureau’s American Community Survey, to first examine the distribution of poverty across different kinds of suburban communities and then the degree of racial and ethnic segregation within and across different kinds of suburban communities. The goal of the analyses is to better understand how policy solutions might best address racial and economic inequality in the suburbs

Exiting shelter: an epidemiological analysis of barriers and facilitators for families

This study examines the role of individual- and family-level factors in predicting the length of shelter stays for homeless families. Interviews were conducted with all families exiting one of six emergency family shelters in Worcester, Massachusetts, between November 2006, and November 2007. Analyses, using an ordinary least squares regression model, find that families with a positive alcohol or drug screen in the year prior stay 85 days longer than those without a positive screen; families leaving shelter with a housing subsidy stay 66 days longer than those leaving without a subsidy.Demographic factors, education, employment, health, and mental health are not found to predict shelter stay duration. Consistent with prior research, housing resources relate to families\u27 time in shelter; with the exception of a positive substance abuse screen, individual-level problems are not related to their time in shelter. Efforts to expand these resources at the local, state, and national levels are a high priority

Using Typologies to Frame Poverty and Service Delivery in Suburban America

Poverty in the suburbs is growing, but there is great diversity in the rates of growth of poverty as well as causes and consequences of the growth across different kinds of suburbs. Suburban typologies, systems to group different types of suburbs, are a useful tool for understanding the variation among suburbs and highlighting potential strategies for addressing poverty. This paper discusses why typologies of suburban communities are important, what factors have been considered in the development and use of typologies, what typologies have been developed to date, and lastly, how typologies can be used to inform strategies for addressing suburban poverty. Suburban typologies can assist in understanding the variation between suburbs in the overall level, duration, and causes of poverty as well as variation in resources, services, and opportunities available for addressing it (Allard & Roth, 2010; Kneebone & Berube, 2013). For example, suburbs experiencing a sharp increase in poverty coupled with large increases in population may have different social service needs than suburbs with sharp poverty increases and little or no growth in population. The typology research sheds light on those suburbs that are experiencing the most significant impacts from increases in poverty and can identify appropriate policy tools and strategies to help communities cope with poverty. Yet, typologies vary with respect to how suburbs are defined, which suburbs are included, and what factors are considered in their development. Not one consistent definition of suburb is used across the typologies that have been developed. Instead, different researchers classify different geographic areas as suburbs, in part, based on the availability of data. Typologies also differ in the sample of suburbs that are being classified. Some researchers focus on all suburban areas, whereas others focus more narrowly on subsets of suburbs, such as inner-ring suburbs or economically distressed suburbs. Finally, researchers use a range of factors and methodologies to develop these typologies including a number of different economic, demographic, and historical factors (Hanlon, 2010; Hanlon, Vicino, & Short, 2006; Mikelbank, 2004; Orfield & Luce, 2012). Their differences not withstanding, taken together, the suburban typologies that have been developed reveal a number of common findings related to the economic vitality and vulnerability of suburbs. Increasingly larger populations of suburban residents live in communities that do not resemble traditional perceptions of prosperous suburbs. Instead, they live in a diverse set of communities including those characterized by poor economic health with low average income and home values, less housing stability, large populations, diverse family structures and racial composition, and varying levels and composition of employment). Although poverty is increasing in suburbs throughout the country, it is growing fastest in distressed suburbs, which tend to be highly racially segregated and fiscally constrained. Moreover, suburbs closest to central cities are increasingly poor and increasingly non-white. The combination of population growth and economic decline in these communities serve as barriers for addressing the increase in poverty

Negatively Charged Gangliosides Promote Membrane Association of Amphipathic Neurotransmitters

Lipophilic neurotransmitters (NTs) such as dopamine are chemical messengers enabling neurotransmission by adhering onto the extracellular surface of the post-synaptic membrane in a synapse, followed by binding to their receptors. Previous studies have shown that the strength of the NT-membrane association is dependent on the lipid composition of the membrane. Negatively charged lipids such as phosphatidylserine, phosphatidylglycerol, and phosphatidic acid have been indicated to promote NT-membrane binding, however these anionic lipids reside almost exclusively in the intracellular leaflet of the post-synaptic membrane instead of the extracellular leaflet facing the synaptic cleft. Meanwhile, the extracellular leaflet is relatively rich in biologically relevant anionic gangliosides such as monosialotetrahexosylganglioside (GM1), yet the role of gangliosides in NT-membrane association is not clear. Here, we explored the role of GM1 in modulating the binding of dopamine and histamine (as amphipathicicationic NTs) as well as acetylcholine (as a hydrophilic/cationic NT) with the post-synaptic membrane surface. Atomistic molecular dynamics simulations and free energy calculations indicated that GM1 fosters membrane association of histamine and dopamine. For acetylcholine, this effect was not observed. The in silico results suggest that gangliosides form a charge-based vestibule in front of the post-synaptic membrane, attracting amphipathic NTs to the vicinity of the membrane. The results also stress the importance to understand the significance of the structural details of NTs, as exemplified by the GM1-acetylcholine interaction. In a larger context, the NT-membrane adherence, coupled to lateral diffusion in the membrane plane, is proposed to improve neurotransmission efficiency by advancing NT entry into the membrane-embedded ligand-binding sites. (C) 2018 IBRO. Published by Elsevier Ltd. All rights reserved.Peer reviewe

Analysis of 3 years of data from the gravitational wave detectors EXPLORER and NAUTILUS

We performed a search for short gravitational wave bursts using about 3 years of data of the resonant bar detectors Nautilus and Explorer. Two types of analysis were performed: a search for coincidences with a low background of accidentals (0.1 over the entire period), and the calculation of upper limits on the rate of gravitational wave bursts. Here we give a detailed account of the methodology and we report the results: a null search for coincident events and an upper limit that improves over all previous limits from resonant antennas, and is competitive, in the range h_rss ~1E-19, with limits from interferometric detectors. Some new methodological features are introduced that have proven successful in the upper limits evaluation.Comment: 12 pages, 12 figure

Belowground carbon transfer across mycorrhizal networks among trees: Facts, not fantasy

The mycorrhizal symbiosis between fungi and plants is among the oldest, ubiquitous and most important interactions in terrestrial life on Earth. Carbon (C) transfer across a common mycorrhizal network (CMN) was demonstrated over half a century ago in the lab (Reid and Woods 1969), and later in the field (Simard et al. 1997). Recent years have seen ample progress in this research direction, including evidence for ecological significance of carbon transfer (Klein et al. 2016). Furthermore, specific cases where the architecture of mycorrhizal networks have been mapped (Beiler et al. 2015) and CMNC transfer from mature trees to seedlings has been demonstrated (Orrego 2018) have suggested that trees in forests are more connected than once thought (Simard 2021). In a recent Perspective, Karst et al. (2023) offered a valuable critical review warning of overinterpretation and positive citation bias in CMN research. It concluded that while there is evidence for C movement among plants, the importance of CMNs remains unclear, as noted by others too (Henriksson et al. 2023). Here we argue that while some of these claims are justified, factual evidence about belowground C transfer across CMNs is solid and accumulating

Examining the Effect of Charged Lipids on Mitochondrial Outer Membrane Dynamics Using Atomistic Simulations

The outer mitochondrial membrane (OMM) is involved in multiple cellular functions such as apoptosis, inflammation and signaling via its membrane-associated and -embedded proteins. Despite the central role of the OMM in these vital phenomena, the structure and dynamics of the membrane have regularly been investigated in silico using simple two-component models. Accordingly, the aim was to generate the realistic multi-component model of the OMM and inspect its properties using atomistic molecular dynamics (MD) simulations. All major lipid components, phosphatidylinositol (PI), phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS), were included in the probed OMM models. Because increased levels of anionic PS lipids have potential effects on schizophrenia and, more specifically, on monoamine oxidase B enzyme activity, the effect of varying the PS concentration was explored. The MD simulations indicate that the complex membrane lipid composition (MLC) behavior is notably different from the two-component PC-PE model. The MLC changes caused relatively minor effects on the membrane structural properties such as membrane thickness or area per lipid; however, notable effects could be seen with the dynamical parameters at the water-membrane interface. Increase of PS levels appears to slow down lateral diffusion of all lipids and, in general, the presence of anionic lipids reduced hydration and slowed down the PE headgroup rotation. In addition, sodium ions could neutralize the membrane surface, when PI was the main anionic component; however, a similar effect was not seen for high PS levels. Based on these results, it is advisable for future studies on the OMM and its protein or ligand partners, especially when wanting to replicate the correct properties on the water-membrane interface, to use models that are sufficiently complex, containing anionic lipid types, PI in particular.Peer reviewe

Selective effect of cell membrane on synaptic neurotransmission

Atomistic molecular dynamics simulations were performed with 13 non-peptidic neurotransmitters (NTs) in three different membrane environments. The results provide compelling evidence that NTs are divided into membrane-binding and membrane-nonbinding molecules. NTs adhere to the postsynaptic membrane surface whenever the ligand-binding sites of their synaptic receptors are buried in the lipid bilayer. In contrast, NTs that have extracellular ligand-binding sites do not have a similar tendency to adhere to the membrane surface. This finding is a seemingly simple yet important addition to the paradigm of neurotransmission, essentially dividing it into membrane-independent and membrane-dependent mechanisms. Moreover, the simulations also indicate that the lipid composition especially in terms of charged lipids can affect the membrane partitioning of NTs. The revised paradigm, highlighting the importance of cell membrane and specific lipids for neurotransmission, should to be of interest to neuroscientists, drug industry and the general public alike.Peer reviewe