469 research outputs found
The New Deal, Race, and Home Ownership in the 1920s and 1930s
Many federal government housing policies began during the New Deal of the 1930s. Many claim that minorities benefited less from these policies than whites. We estimate the relationships between policies in the 1920s and 1930s and black and white home ownership in farm and nonfarm settings using a pseudo-panel of repeated cross-sections of households in 1920, 1930, and 1940 matched with policy measures in 460 state economic areas. The policies examined include FHA mortgage insurance, HOLC loan refinancing, state mortgage moratoria, farm loan programs, public housing, public works and relief, and payments to farmers to take land out of production.
J024 Role du complexe proteique ERM dans la transmission des effets de lâactivation de lâechangeur NHE1 en reponse a lâacidification des myocytes cardiaques
Nous avons Ă©tudiĂ© le rĂŽle du complexe protĂ©ique ezrine/radixine/ moĂ©sine (ou complexe ERM, reliĂ© au cytosquelette) dans la transmission du signal donnĂ© par lâaugmentation dâactivitĂ© de lâĂ©changeur Na+/H+, NHE1, en rĂ©ponse Ă une acidification intracellulaire. LâĂ©tude a Ă©tĂ© rĂ©alisĂ©e sur myocytes ventriculaires gauches isolĂ©s de coeurs de rats adultes (rats Wistar tĂ©moins et rats diabĂ©tiques GK). La dĂ©tection des protĂ©ines ERM actives (i.e. phosphorylĂ©es) par immuno-marquage a permis de rĂ©vĂ©ler que, dans les conditions basales et en dehors de toute stimulation, ces protĂ©ines sont localisĂ©es au niveau des disques intercalaires, aussi bien dans les myocytes de rats tĂ©moins que de rats GK. Lâacidification entraĂźne une augmentation significative de la phosphorylation des protĂ©ines ERM avec remodelage intracellulaire de ces protĂ©ines; elles sont alors localisĂ©es Ă proximitĂ© des rĂ©cepteurs de la ryanodine, vraisemblablement au niveau des tubules-T. Ces observations ont Ă©tĂ© faites aussi bien dans les cardiomyocytes ventriculaires de rats tĂ©moins que de rats diabĂ©tiques GK, avec un remodelage plus marquĂ© chez ces derniers. Un autre rĂ©sultat dâimportance est lâobservation dâune augmentation dâactivitĂ© de Akt, parallĂšle Ă celle du complexe ERM : augmentation avec lâacidification et absence dâaugmentation lorsque lâacidification a Ă©tĂ© induite en prĂ©sence dâun inhibiteur de NHE1. De plus, lâexploration de deux voies cibles de Akt, la voie mTOR/p70S6K et la voie GSK-3b, a montrĂ© que seule la phosphorylation de la GSK-3b est augmentĂ©e lors dâune stimulation marquĂ©e de lâactivitĂ© de la voie NHE1/ERM/ Akt. Lâensemble de ce travail, nous a permis de mettre en Ă©vidence quâune activitĂ© Ă©levĂ©e de lâĂ©changeur NHE1 constitue un signal capable dâenclencher, via le complexe protĂ©ique ERM, une cascade dâĂ©vĂ©nements intracellulaires pouvant notamment aboutir, comme montrĂ© prĂ©cĂ©demment1, Ă une rĂ©ponse hypertrophique. Ceci nous semble ĂȘtre un rĂ©sultat fondamental qui met en lumiĂšre un rĂŽle important de NHE1, lorsque celui-ci est sollicitĂ© de façon excessive (par exemple au cours dâune ischĂ©mie chronique), Ă cĂŽtĂ© de son rĂŽle reconnu de mĂ©canisme majeur de rĂ©gulation du pH interne des cellules
Small Habitat Commonality Reduces Cost for Human Mars Missions
Most view the Apollo Program as expensive. It was. But, a human mission to Mars will be orders of magnitude more difficult and costly. Recently, NASA's Evolvable Mars Campaign (EMC) mapped out a step-wise approach for exploring Mars and the Mars-moon system. It is early in the planning process but because approximately 80% of the total life cycle cost is committed during preliminary design, there is an effort to emphasize cost reduction methods up front. Amongst the options, commonality across small habitat elements shows promise for consolidating the high bow-wave costs of Design, Development, Test and Evaluation (DDT&E) while still accommodating each end-item's functionality. In addition to DDT&E, there are other cost and operations benefits to commonality such as reduced logistics, simplified infrastructure integration and with inter-operability, improved safety and simplified training. These benefits are not without a cost. Some habitats are sub-optimized giving up unique attributes for the benefit of the overall architecture and because the first item sets the course for those to follow, rapidly developing technology may be excluded. The small habitats within the EMC include the pressurized crew cabins for the ascent vehicle
Synergic PDE3 and PDE4 control intracellular cAMP and cardiac excitation-contraction coupling in a porcine model
International audienc
Kepler-16: A Transiting Circumbinary Planet
We report the detection of a planet whose orbit surrounds a pair of low-mass
stars. Data from the Kepler spacecraft reveal transits of the planet across
both stars, in addition to the mutual eclipses of the stars, giving precise
constraints on the absolute dimensions of all three bodies. The planet is
comparable to Saturn in mass and size, and is on a nearly circular 229-day
orbit around its two parent stars. The eclipsing stars are 20% and 69% as
massive as the sun, and have an eccentric 41-day orbit. The motions of all
three bodies are confined to within 0.5 degree of a single plane, suggesting
that the planet formed within a circumbinary disk.Comment: Science, in press; for supplemental material see
http://www.sciencemag.org/content/suppl/2011/09/14/333.6049.1602.DC1/1210923.Doyle.SOM.pd
Erratum: Establishment of a canine spinal cord injury model induced by epidural balloon compression
A model that provides reproducible, submaximal yet sufficient spinal cord injury is needed to allow experiments leading to development of therapeutic techniques and prediction of clinical outcome to be conducted. This study describes an experimental model for spinal cord injury that uses three different volumes of balloon inflation and durations of compression to create a controlled gradation outcome in adult dogs. Twenty-seven mongrel dogs were used for this study. A 3-french embolectomy catheter was inserted into the epidural space through a left hemilaminectomy hole at the L4 vertebral arch. Balloons were then inflated with 50, 100, or 150 ”l of a contrast agent at the L1 level for 6, 12, or 24 h and spinal canal occlusion (SCO) measured using computed tomography. Olby score was used to evaluate the extent of spinal cord injury and a histopathologic examination was conducted 1 week after surgery. The SCO of the 50, 100, and 150 ”l inflations was 22-46%, 51-70%, and 75-89%, respectively (p < 0.05). Olby scores were diminished significantly by a combination of the level of SCO and duration of inflation in all groups. Olby scores in the groups of 150 ”l-12 h, 150 ”l-24 h, and 100 ”l-24 h were 0.5, 0, and 1.7, respectively. Based on these results, a SCO > 50% for 24 h, and > 75% for 12 h induces paraplegia up to a week after spinal cord injury
Growth rate and age effects on Mya arenaria shell chemistry: Implications for biogeochemical studies
This paper is not subject to U.S. copyright. The definitive version was published in Journal of Experimental Marine Biology and Ecology 355 (2008): 153-163, doi:10.1016/j.jembe.2007.12.022.The chemical composition of bivalve shells can reflect that of their environment, making them useful indicators of climate, pollution, and ecosystem changes. However, biological factors can also influence chemical properties of biogenic carbonate. Understanding how these factors affect chemical incorporation is essential for studies that use elemental chemistry of carbonates as indicators of environmental parameters. This study examined the effects of bivalve shell growth rate and age on the incorporation of elements into juvenile softshell clams, Mya arenaria. Although previous studies have explored the effects of these two biological factors, reports have differed depending on species and environmental conditions. In addition, none of the previous studies have examined growth rate and age in the same species and within the same study. We reared clams in controlled laboratory conditions and used solution-based inductively coupled plasma mass spectrometry (ICP-MS) analysis to explore whether growth rate affects elemental incorporation into shell. Growth rate was negatively correlated with Mg, Mn, and Ba shell concentration, possibly due to increased discrimination ability with size. The relationship between growth rate and Pb and Sr was unresolved. To determine age effects on incorporation, we used laser ablation ICP-MS to measure changes in chemical composition across shells of individual clams. Age affected incorporation of Mn, Sr, and Ba within the juvenile shell, primarily due to significantly different elemental composition of early shell material compared to shell accreted later in life. Variability in shell composition increased closer to the umbo (hinge), which may be the result of methodology or may indicate an increased ability with age to discriminate against ions that are not calcium or carbonate. The effects of age and growth rate on elemental incorporation have the potential to bias data interpretation and should be considered in any biogeochemical study that uses bivalves as environmental indicators.This work was supported by NSF project numbers OCE-0241855 and OCE-0215905
Orai1 Channel Inhibition Preserves Left Ventricular Systolic Function and Normal Ca2+ Handling After Pressure Overload
Background: Orai1 is a critical ion channel subunit, best recognized as a mediator of storeoperated Ca2+ entry (SOCE) in non-excitable cells. SOCE has recently emerged as a key contributor of cardiac hypertrophy and heart failure but the relevance of Orai1 is still unclear.
Methods: To test the role of these Orai1 channels in the cardiac pathophysiology, a transgenic mouse was generated with cardiomyocyte-specific expression of an ion pore-disruptive Orai1R91W mutant (C-dnO1). Synthetic chemistry and channel screening strategies were used to develop JPIII, a small-molecule Orai1 channel inhibitor suitable for in vivo delivery.
Results: Adult mice subjected to transverse aortic constriction (TAC) developed cardiac hypertrophy and reduced ventricular function associated with increased Orai1 expression and Orai1-dependent SOCE (assessed by Mn2+ influx). C-dnO1 mice displayed normal cardiac electromechanical function and cellular excitation-contraction coupling despite reduced Orai1-dependent SOCE. 5 weeks after TAC, C-dnO1 mice were protected from systolic dysfunction (assessed by preserved left ventricular fractional shortening and ejection fraction) even if increased cardiac mass and pro-hypertrophic markers induction were observed. This is correlated with a protection from TAC-induced cellular Ca2+ signaling alterations (increased SOCE, decreased [Ca2+]i transients amplitude and decay rate, lower SR Ca2+ load and depressed cellular contractility) and SERCA2a downregulation in ventricular cardiomyocytes from C-dnO1 mice, associated with blunted Pyk2 signaling. There was also less fibrosis in heart sections from CdnO1 mice after TAC. Moreover, 3 weeks treatment with JPIII following 5 weeks of TAC confirmed the translational relevance of an Orai1 inhibition strategy during hypertrophic insult.
Conclusions: The findings suggest a key role of cardiac Orai1 channels and the potential for Orai1 channel inhibitors as inotropic therapies for maintaining contractility reserve after hypertrophic stress
The relationship between quality of research and citation frequency
BACKGROUND: Citation counts are often regarded as a measure of the utilization and contribution of published articles. The objective of this study is to assess whether statistical reporting and statistical errors in the analysis of the primary outcome are associated with the number of citations received. METHODS: We evaluated all original research articles published in 1996 in four psychiatric journals. The statistical and reporting quality of each paper was assessed and the number of citations received up to 2005 was obtained from the Web of Science database. We then examined whether the number of citations was associated with the quality of the statistical analysis and reporting. RESULTS: A total of 448 research papers were included in the citation analysis. Unclear or inadequate reporting of the research question and primary outcome were not statistically significantly associated with the citation counts. After adjusting for journal, extended description of statistical procedures had a positive effect on the number of citations received. Inappropriate statistical analysis did not affect the number of citations received. Adequate reporting of the primary research question, statistical methods and primary findings were all associated with the journal visibility and prestige. CONCLUSION: In this cohort of published research, measures of reporting quality and appropriate statistical analysis were not associated with the number of citations. The journal in which a study is published appears to be as important as the statistical reporting quality in ensuring dissemination of published medical science
- âŠ