118 research outputs found
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
Mesenchymal Stromal Cells and Platelet-Rich Plasma Promote Tendon Allograft Healing in Ovine Anterior Cruciate Ligament Reconstruction
Purpose
The effect of bone marrow mesenchymal stromal cells (BMSCs) and platelet-rich plasma (PRP) on tendon allograft maturation in a large animal anterior cruciate ligament (ACL) reconstruction model was reported for the first time. It was hypothesised that compared with non-augmented ACL reconstruction, BMSCs and PRP would enhance graft maturation after 12 weeks and this would be detected using magnetic resonance imaging (MRI).
Methods
Fifteen sheep underwent unilateral tendon allograft ACL reconstruction using aperture fixation and were randomised into three groups (n = 5). Group 1 received 10 million allogeneic BMSCs in 2 ml fibrin sealant; Group 2 received 12 ml PRP in a plasma clot injected into the graft and bone tunnels; and Group 3 (control) received no adjunctive treatment. At autopsy at 12 weeks, a graft maturation score was determined by the sum for graft integrity, synovial coverage and vascularisation, graft thickness and apparent tension, and synovial sealing at tunnel apertures. MRI analysis (n = 2 animals per group) of the signal–noise quotient (SNQ) and fibrous interzone (FIZ) was used to evaluate intra-articular graft maturation and tendon–bone healing, respectively. Spearman’s rank correlation coefficient (r) of SNQ, autopsy graft maturation score and bone tunnel diameter were analysed.
Results
The BMSC group (p = 0.01) and PRP group (p = 0.03) had a significantly higher graft maturation score compared with the control group. The BMSC group scored significantly higher for synovial sealing at tunnel apertures (p = 0.03) compared with the control group. The graft maturation score at autopsy significantly correlated with the SNQ (r = − 0.83, p < 0.01). The tunnel diameter of the femoral tunnel at the aperture (r = 0.883, p = 0.03) and mid-portion (r = 0.941, p = 0.02) positively correlated with the SNQ.
Conclusions
BMSCs and PRP significantly enhanced graft maturation, which indicates that orthobiologics can accelerate the biologic events in tendon allograft incorporation. Femoral tunnel expansion significantly correlated with inferior maturation of the intra-articular graft. The clinical relevance of this study is that BMSCs and PRP enhance allograft healing in a translational model, and biological modulation of graft healing can be evaluated non-invasively using MRI
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Effect of Demineralized Bone Matrix, Bone Marrow Mesenchymal Stromal Cells, and Platelet-Rich Plasma on Bone Tunnel Healing After Anterior Cruciate Ligament Reconstruction: A Comparative Micro-Computed Tomography Study in a Tendon Allograft Sheep Model
Background:
The effect of demineralized bone matrix (DBM), bone marrow–derived mesenchymal stromal cells (BMSCs), and platelet-rich plasma (PRP) on bone tunnel healing in anterior cruciate ligament reconstruction (ACLR) has not been comparatively assessed.
Hypothesis:
These orthobiologics would reduce tunnel widening, and the effects on tunnel diameter would be correlated with tunnel wall sclerosis.
Study Design:
Controlled laboratory study.
Methods:
A total of 20 sheep underwent unilateral ACLR using tendon allograft and outside-in interference screw fixation. The animals were randomized into 4 groups (n = 5 per group): Group 1 received 4mL of DBM paste, group 2 received 10 million BMSCs in fibrin sealant, group 3 received 12 mL of activated leukocyte-poor platelet-rich plasma, and group 4 (control) received no treatment. The sheep were euthanized after 12 weeks, and micro-computed tomography scans were performed. The femoral and tibial tunnels were divided into thirds (aperture, midportion, and exit), and the trabecular bone structure, bone mineral density (BMD), and tunnel diameter were measured. Tunnel sclerosis was defined by a higher bone volume in a 250-µm volume of interest compared with a 4-mm volume of interest surrounding the tunnel.
Results:
Compared with the controls, the DBM group had a significantly higher bone volume fraction (bone volume/total volume [BV/TV]) (52.7% vs 31.8%; P = .020) and BMD (0.55 vs 0.47 g/cm3; P = .008) at the femoral aperture and significantly higher BV/TV at femoral midportion (44.2% vs 32.9%; P = .038). There were no significant differences between the PRP and BMSC groups versus controls in terms of trabecular bone analysis or BMD. In the controls, widening at the femoral tunnel aperture was significantly greater than at the midportion (46.7 vs 41.7 mm2; P = .034). Sclerosis of the tunnel was common and most often seen at the femoral aperture. In the midportion of the femoral tunnel, BV/TV (r = 0.52; P = .019) and trabecular number (r S = 0.50; P = .024) were positively correlated with tunnel widening.
Conclusion:
Only DBM led to a significant increase in bone volume, which was seen in the femoral tunnel aperture and midportion. No treatment significantly reduced bone tunnel widening. Tunnel sclerosis in the femoral tunnel midportion was correlated significantly with tunnel widening
Poverty and Service Delivery in Suburban America Framing Paper
In the United States today, contrary to popular belief, living in the suburbs is not synonymous with living the American dream. An unprecedented number of people in the suburbs are living on household incomes of less than $20,000, many on much less. Increasingly, individuals and their families need to rely on services and public benefits to meet their basic needs (Kneebone & Berube, 2013).
Over the past 30 years, poverty in the suburbs has grown due to multiple factors, including job decentralization, shifts in the location of affordable and subsidized housing, and the relocation to the suburbs of lower income immigrants and minorities (Covington, Freeman, & Stoll, 2011; Frey, 2011a). The rate of growth in suburban poverty has been particularly high in the past decade, outpacing growth in both urban and rural areas. During the Great Recession (2007-2009), high rates of unemployment and underemployment and the home foreclosure crisis brought the number of people living in poverty in the suburbs to an all-time high. Today, suburban areas are home to about 40 percent of all poor people in the country, an increase from 25 percent in 1980. Furthermore, in the 100 largest metropolitan areas, more people are living in poverty in the suburbs than in urban areas (Frey, 2011b). Suburbs are now facing a range of challenges traditionally associated with cities, such as high rates of unemployment and underemployment, lower educational attainment, food insecurity, and lack of access to health care. The increase in the suburban poverty rate is straining social service providers and local governments at a time when resources are shrinking (Allard & Roth, 2010).
The Office of the Assistant Secretary for Planning and Evaluation (ASPE) of the U.S. Department of Health and Human Services (HHS) seeks to better understand poverty and service delivery in suburban America, including how the dynamics of suburban poverty may differ from those in rural and urban communities and whether service models may need to be tailored to meet these differences. To that end, ASPE commissioned this framing paper to review and synthesize existing research, analyze the characteristics and service needs of those living in poverty in the suburbs, and identify information and research needed to more fully understand and guide efforts to address suburban poverty.
To prepare this review, we used three types of information sources: existing literature, both published and unpublished; a select number of key informant interviews; and two sources of extant U.S. Census Bureau household survey data: the Annual Social and Economic Supplement to the Current Population Survey (CPS), which provides an annual count of the number of people living below 100 percent of the federal poverty level from 1959 to 2011, and the 2009-2011 American Community Survey (ACS) Weighted 3-Year Restricted-Use Files, a household survey of a nationally representative sample of individuals. These data provide information about all suburbs, including but not limited to, the 100 largest metropolitan areas (see Appendix 1).
This paper will serve to frame the discussion during the Poverty and Service Delivery in Suburban America Roundtable, to be convened in 2014. The roundtable will bring together researchers, policy
5 experts, practitioners, and federal staff to discuss the issues raised in this paper and gaps in the research, formulate new research questions, consider the implications of the research for service delivery and public benefits, and assess opportunities for HHS and broader federal engagement
Poverty and Service Delivery in Suburban America Framing Paper
In the United States today, contrary to popular belief, living in the suburbs is not synonymous with living the American dream. An unprecedented number of people in the suburbs are living on household incomes of less than $20,000, many on much less. Increasingly, individuals and their families need to rely on services and public benefits to meet their basic needs (Kneebone & Berube, 2013).
Over the past 30 years, poverty in the suburbs has grown due to multiple factors, including job decentralization, shifts in the location of affordable and subsidized housing, and the relocation to the suburbs of lower income immigrants and minorities (Covington, Freeman, & Stoll, 2011; Frey, 2011a). The rate of growth in suburban poverty has been particularly high in the past decade, outpacing growth in both urban and rural areas. During the Great Recession (2007-2009), high rates of unemployment and underemployment and the home foreclosure crisis brought the number of people living in poverty in the suburbs to an all-time high. Today, suburban areas are home to about 40 percent of all poor people in the country, an increase from 25 percent in 1980. Furthermore, in the 100 largest metropolitan areas, more people are living in poverty in the suburbs than in urban areas (Frey, 2011b). Suburbs are now facing a range of challenges traditionally associated with cities, such as high rates of unemployment and underemployment, lower educational attainment, food insecurity, and lack of access to health care. The increase in the suburban poverty rate is straining social service providers and local governments at a time when resources are shrinking (Allard & Roth, 2010).
The Office of the Assistant Secretary for Planning and Evaluation (ASPE) of the U.S. Department of Health and Human Services (HHS) seeks to better understand poverty and service delivery in suburban America, including how the dynamics of suburban poverty may differ from those in rural and urban communities and whether service models may need to be tailored to meet these differences. To that end, ASPE commissioned this framing paper to review and synthesize existing research, analyze the characteristics and service needs of those living in poverty in the suburbs, and identify information and research needed to more fully understand and guide efforts to address suburban poverty.
To prepare this review, we used three types of information sources: existing literature, both published and unpublished; a select number of key informant interviews; and two sources of extant U.S. Census Bureau household survey data: the Annual Social and Economic Supplement to the Current Population Survey (CPS), which provides an annual count of the number of people living below 100 percent of the federal poverty level from 1959 to 2011, and the 2009-2011 American Community Survey (ACS) Weighted 3-Year Restricted-Use Files, a household survey of a nationally representative sample of individuals. These data provide information about all suburbs, including but not limited to, the 100 largest metropolitan areas (see Appendix 1).
This paper will serve to frame the discussion during the Poverty and Service Delivery in Suburban America Roundtable, to be convened in 2014. The roundtable will bring together researchers, policy
5 experts, practitioners, and federal staff to discuss the issues raised in this paper and gaps in the research, formulate new research questions, consider the implications of the research for service delivery and public benefits, and assess opportunities for HHS and broader federal engagement
Damage patterns at the head-stem taper junction helps understand the mechanisms of material loss
Background:
Material loss at the taper junction of metal-on-metal total hip replacements (MOM THRs) has been implicated in their early failure. The mechanisms of material loss are not fully understood; analysis of the patterns of damage at the taper can help us better understand why material loss occurs at this junction.
Methods:
We mapped the patterns of material loss in a series of 155 MOM-THRs received at our centre by scanning the taper surface using a roundness-measuring machine. We
examined these material loss maps to develop a five-tier classification system based
on visual differences between different patterns. We correlated these patterns to
surgical, implant and patient factors known to be important for head-stem taper damage.
Results:
We found that 63 implants had ‘minimal damage’ at the taper (material loss <1mm3 )
and the remaining 92 implants could be categorised by four distinct patterns of taper
material loss. We found that (1) head diameter and (2) time to revision were key
significant variables separating the groups.
Conclusion:
These material loss maps allow us to suggest different mechanisms that dominate the cause of the material loss in each pattern: (a) corrosion, (b) mechanically assisted corrosion or (c) intra-operative damage or poor size tolerances leading to toggling of trunnion in taper
How the oxygen tolerance of a [NiFe]-hydrogenase depends on quaternary structure
‘Oxygen-tolerant’ [NiFe]-hydrogenases can catalyze H(2) oxidation under aerobic conditions, avoiding oxygenation and destruction of the active site. In one mechanism accounting for this special property, membrane-bound [NiFe]-hydrogenases accommodate a pool of electrons that allows an O(2) molecule attacking the active site to be converted rapidly to harmless water. An important advantage may stem from having a dimeric or higher-order quaternary structure in which the electron-transfer relay chain of one partner is electronically coupled to that in the other. Hydrogenase-1 from E. coli has a dimeric structure in which the distal [4Fe-4S] clusters in each monomer are located approximately 12 Å apart, a distance conducive to fast electron tunneling. Such an arrangement can ensure that electrons from H(2) oxidation released at the active site of one partner are immediately transferred to its counterpart when an O(2) molecule attacks. This paper addresses the role of long-range, inter-domain electron transfer in the mechanism of O(2)-tolerance by comparing the properties of monomeric and dimeric forms of Hydrogenase-1. The results reveal a further interesting advantage that quaternary structure affords to proteins
Research strategies for organizational history:a dialogue between historical theory and organization theory
If history matters for organization theory, then we need greater reflexivity regarding the epistemological problem of representing the past; otherwise, history might be seen as merely a repository of ready-made data. To facilitate this reflexivity, we set out three epistemological dualisms derived from historical theory to explain the relationship between history and organization theory: (1) in the dualism of explanation, historians are preoccupied with narrative construction, whereas organization theorists subordinate narrative to analysis; (2) in the dualism of evidence, historians use verifiable documentary sources, whereas organization theorists prefer constructed data; and (3) in the dualism of temporality, historians construct their own periodization, whereas organization theorists treat time as constant for chronology. These three dualisms underpin our explication of four alternative research strategies for organizational history: corporate history, consisting of a holistic, objectivist narrative of a corporate entity; analytically structured history, narrating theoretically conceptualized structures and events; serial history, using replicable techniques to analyze repeatable facts; and ethnographic history, reading documentary sources "against the grain." Ultimately, we argue that our epistemological dualisms will enable organization theorists to justify their theoretical stance in relation to a range of strategies in organizational history, including narratives constructed from documentary sources found in organizational archives. Copyright of the Academy of Management, all rights reserved
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