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Certain geological features have been interpreted as evidence of channelized magma flow in the mantle, which is a compacting porous medium. Aharonov et al. (J. Geophys. Res., vol. 100 (B10), 1995, pp. 20433–20450) developed a simple model of reactive porous flow and numerically analysed its instability to channels. The instability relies on magma advection against a chemical solubility gradient and the porosity-dependent permeability of the porous host rock. We extend the previous analysis by systematically mapping out the parameter space. Crucially, we augment numerical solutions with asymptotic analysis to better understand the physical controls on the instability. We derive scalings for the critical conditions of the instability and analyse the associated bifurcation structure. We also determine scalings for the wavelengths and growth rates of the channel structures that emerge. We obtain quantitative theories for and a physical understanding of, first, how advection or diffusion over the reactive time scale sets the horizontal length scale of channels and, second, the role of viscous compaction of the host rock, which also affects the vertical extent of channelized flow. These scalings allow us to derive estimates of the dimensions of emergent channels that are consistent with the geologic record.
OBJECTIVES/SPECIFIC AIMS: One of the key difficulties in predicting allergenic pollen exposures has been a lack of information on source plant location and abundance. However, the increasing availability of spatially explicit data from remote sensing offers new opportunities to create comprehensive inventories of allergenic pollen producing plants. METHODS/STUDY POPULATION: In this study, we use a spatially oriented field survey to map common ragweed (Ambrosia artemisiifolia) in Detroit, MI, USA. We then combine this with remote sensing imagery and LiDAR to predict ragweed presence and potential pollen production across 344 km2 of Detroit. Finally, we compare this with measurements of airborne pollen concentrations collected throughout the city. RESULTS/ANTICIPATED RESULTS: Our initial results show that ragweed is present in ~2% of the city, and its presence and abundance are strongly associated with demolished building (p<0.001). The uneven distribution of ragweed plants across the city leads to substantially higher pollen concentrations in neighborhoods where more buildings have been recently demolished. DISCUSSION/SIGNIFICANCE OF IMPACT: Our approach offers an effective way to quantify allergenic pollen production, airborne concentrations, and exposures across a large metropolitan area. This in turn provides insight on how to best reduce airborne pollen concentrations: in this case, by changing post-demolition land management practices.
The high-speed impact of a droplet on a bulk fluid at high Weber number (We) is not well understood but is relevant to the production of marine aerosol by raindrop impact on the sea surface. These splashes produce a subsurface cavity and a crown which closes into a bubble canopy, but a floating layer of immiscible oil, such as a crude oil slick, alters the splash dynamics. The effects of oil layer fluid properties and thickness, droplet size and impact speed are examined by high-speed visualization. Oil layer rupture and crown behaviour are classified by dimensional scaling. The subsurface cavity volume for impact on thick layers is shown to depend on the Reynolds number (Re), although canopy formation at high Re introduces a competing We effect since rapid canopy closure is found to retard cavity expansion. Time-resolved kinematic measurements show that thin crude oil slicks similarly alter crown closure and cavity growth. The size and spatial distributions of airborne droplets are examined using high-speed holographic microscopy. The droplets have a bimodal distribution with peaks at 50 and
and are clustered by size at different elevation angles. Small droplets (
) are ejected primarily at shallow angles, indicating production by splashing within the first
and by breakup of microligaments. Larger droplets (
) are found at steeper elevation angles, indicating later production by capillary instability acting on large ligaments protruding upward from the crown. Intermittent droplet release while the ligaments grow and sweep upward is thought to contribute to the size-dependent spatial ordering. Greater numbers of small droplets are produced at high elevation angles when a crude oil layer is present, indicating satellite droplet formation from ligament breakup. A crude oil layer also increases the target fluid Ohnesorge number, leading to creation of an intact ejecta sheet, which then ruptures to form aerosolized oil droplets.
Major depressive disorder during pregnancy associates with potentially detrimental consequences for mother and child. The current study examined peripheral blood gene expression as a potential biomarker for prenatal depressive symptoms.
Maternal RNA from whole blood, plasma and the Beck Depression Inventory were collected longitudinally from preconception through the third trimester of pregnancy in 106 women with a lifetime history of mood or anxiety disorders. The expression of 16 genes in whole blood involved in glucorticoid receptor (GR) signaling was assessed using real-time polymerase chain reaction. In parallel, plasma concentrations of progesterone, estradiol and cortisol were measured. Finally, we assessed ex vivo GR sensitivity in peripheral blood cells from a subset of 29 women.
mRNA expression of a number of GR-complex regulating genes was up-regulated over pregnancy. Women with depressive symptoms showed significantly smaller increases in mRNA expression of four of these genes – FKBP5, BAG1, NCOA1 and PPID. Ex vivo stimulation assays showed that GR sensitivity diminished with progression of pregnancy and increasing maternal depressive symptoms. Plasma concentrations of gonadal steroids and cortisol did not differ over pregnancy between women with and without clinically relevant depressive symptoms.
The presence of prenatal depressive symptoms appears to be associated with altered regulation of GR sensitivity. Peripheral expression of GR co-chaperone genes may serve as a biomarker for risk of developing depressive symptoms during pregnancy. The presence of such biomarkers, if confirmed, could be utilized in treatment planning for women with a psychiatric history.
Cox and Katz argue that the massive wave of redistricting that occurred post-1964 created an “incumbency advantage” in the U.S. House. They find that the political composition of the courts and state legislatures that redrew the districts are critical to understanding which party benefited from redistricting. On balance, they find that the redistricting created a larger advantage for Republican incumbents.
THE REAPPORTIONMENT REVOLUTION
A Sketch of the Reapportionment Revolution
The Court's Decisions
On March 26, 1962, the Supreme Court handed down its decision in the case of Baker v. Carr, thus initiating what has since been known as the reapportionment revolution. The suit was brought by urban plaintiffs in Tennessee, who challenged their state legislature's failure to reapportion despite widespread population shifts that had made urban districts vastly more populous than their rural counterparts. The ramifications of the case were clearly national, because urban and especially suburban Americans were significantly underrepresented in state legislatures throughout the country. Thus, although the Court limited itself to declaring that state legislative reapportionment was justiciable, leaving more specific action in the case to the lower courts, its decision was immediately seen as a revolutionary step – one the Court had repeatedly declined to take.
The immediate consequence of Baker was more litigation. Indeed, within a year of the decision, all but 14 states were involved in reapportionment suits, and the Supreme Court used some of these cases to stake out a clearer substantive position.
Individuals who are unaware of the price do not derive more enjoyment from more expensive wine. In a sample of more than 6,000 blind tastings, we find that the correlation between price and overall rating is small and negative, suggesting that individuals on average enjoy more expensive wines slightly less. For individuals with wine training, however, we find indications of a non-negative relationship between price and enjoyment. Our results are robust to the inclusion of individual fixed effects, and are not driven by outliers: when omitting the top and bottom deciles of the price distribution, our qualitative results are strengthened, and the statistical significance is improved further. These findings suggest that non-expert wine consumers should not anticipate greater enjoyment of the intrinsic qualities of a wine simply because it is expensive or is appreciated by experts. (JEL Classification: L15, L66, M30, Q13)
Postresuscitation disease and its care
Uwe Ebmeyer, Clinic for Anaesthesiology and Intensive Therapy, Otto-von-Guericke,
Laurence M. Katz, Department of Emergency Medicine and University, Magdeburg, Germany,
Kevin R. Ward, University of North Carolina Department of Emergency Medicine, Virginia Commonwealth University, Detroit, MI, USA,
Robert W. Neumar, Department of Emergency Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
Multiple brain-damaging processes occur both during cardiac arrest and after return of spontaneous circulation (ROSC). The first aspect, the actual arrest, is best treated by rapid institution of artificial circulation/ventilation and early ROSC. The details and physiologic background for these procedures are discussed in previous chapters. This chapter will focus on the early period after restoration of spontaneous circulation and treatment aimed to prevent or minimize postischemic brain damage after restoration of spontaneous circulation. The ultimate importance of the postreperfusion (after ROSC) phase for long-term outcome is often underestimated. Currently it is believed that the majority of brain-injuring processes occur not during the no-flow state (cardiac arrest) but during resuscitative reperfusion. This latter stage includes a trickle-, a low-, and a temporary high-flow period. Since significant injury occurs during the resuscitation period, there is a window of opportunity to intervene and affect outcome. Nevertheless, the development of treatments for the multifactorial postresuscitation syndrome is complex and time-consuming and has thus far led to disappointing results. Numerous treatments effective in the laboratory have failed or been shown to have an almost undetectable benefit in clinical studies. Large multicenter studies – the only way to detect small(er) benefits – are extremely expensive and time-consuming and require an enormous administrative and financial investment. Sometimes ethical concerns about obtaining informed consent make clinical resuscitation research increasingly difficult. Nevertheless, definitive clinical studies are the only way to prove the effectiveness of resuscitation and postresuscitation treatment; clinically relevant laboratory studies may only help to select those that are most promising.