This special issue examines innovative methods in three areas of protest studies: (1) survey methodology and scaling, (2) the development and assessment of political event data, and (3) methods of ...contextual analysis. The articles provide new techniques and general methodologies for improving the quality of data that we have about protest, especially in the comparative study of protest.
Using a recently compiled global marine data set of dissolved helium isotopes and helium and neon concentrations, we make an estimate of the inventory of hydrothermal 3He in the Southern Ocean to be ...4.9 ± 0.6 × 104 moles. Under the assumption that the bulk of the hydrothermally sourced 3He is upwelled there, we use recent estimates of the global hydrothermal 3He flux to determine an e‐folding residence time of 99 ± 18 years, depending on assumptions of water mass and upwelling boundaries. Our estimate is within the broad range of values obtained from recent Southern Ocean circulation models.
Plain Language Summary
Seafloor hydrothermal systems inject significant amounts of dissolved iron, but it remains unknown what fraction of that trace element survives in situ chemical scavenging to upwell in the Southern Ocean to arrive at the sea surface. Since iron is a necessary trace‐level nutrient for marine biological productivity, knowledge of the time it takes for deep water to rise to the surface is important. Along with dissolved iron, helium‐3, a rare, inert isotope, is also injected into the deep water. Since the global flux of this isotope has been independently determined by large‐scale ocean models, we can estimate the upwelling time scale by dividing it into the inventory of this isotope in the Southern Ocean.
Key Points
The Southern Ocean contains an inventory of hydrothermally‐sourced 3He
If we divide this inventory by the global hydrothermal flux that must support this inventory, we obtain an estimate of an upwelling time scale for deep waters in the Southern Ocean
Hydrothermal venting along mid-ocean ridges exerts an important control on the chemical composition of sea water by serving as a major source or sink for a number of trace elements in the ocean. Of ...these, iron has received considerable attention because of its role as an essential and often limiting nutrient for primary production in regions of the ocean that are of critical importance for the global carbon cycle. It has been thought that most of the dissolved iron discharged by hydrothermal vents is lost from solution close to ridge-axis sources and is thus of limited importance for ocean biogeochemistry. This long-standing view is challenged by recent studies which suggest that stabilization of hydrothermal dissolved iron may facilitate its long-range oceanic transport. Such transport has been subsequently inferred from spatially limited oceanographic observations. Here we report data from the US GEOTRACES Eastern Pacific Zonal Transect (EPZT) that demonstrate lateral transport of hydrothermal dissolved iron, manganese, and aluminium from the southern East Pacific Rise (SEPR) several thousand kilometres westward across the South Pacific Ocean. Dissolved iron exhibits nearly conservative (that is, no loss from solution during transport and mixing) behaviour in this hydrothermal plume, implying a greater longevity in the deep ocean than previously assumed. Based on our observations, we estimate a global hydrothermal dissolved iron input of three to four gigamoles per year to the ocean interior, which is more than fourfold higher than previous estimates. Complementary simulations with a global-scale ocean biogeochemical model suggest that the observed transport of hydrothermal dissolved iron requires some means of physicochemical stabilization and indicate that hydrothermally derived iron sustains a large fraction of Southern Ocean export production.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
One of the defining features of episodic long-term memory is that it includes information about the temporal context in which an event occurred. Little is known about the regions that support the ...encoding of temporal information in the human brain, although previous work has suggested a role for the lateral prefrontal cortex (PFC) and medial temporal lobes (MTL). Here we used event-related fMRI to examine the relationship between activity at encoding and subsequent memory for temporal context. Participants were scanned while performing a serial order working memory task with pictures of common objects and were later tested for temporal memory at two different timescales. In the coarse temporal memory test, participants viewed one object from each trial and indicated approximately when during the course of the experiment it had appeared. In the fine temporal memory test, participants were shown the remaining objects from each trial and asked to recall the order in which they had been originally presented. Activity in the parahippocampal cortex predicted subsequent fine temporal accuracy, whereas coarse temporal accuracy was predicted by activity in several regions of the PFC, as well as in the hippocampus. Additional multivoxel pattern analyses revealed evidence implicating the rostrolateral PFC in the representation of time-varying contextual states in a manner similar to that proposed by computational theories of temporal context memory. These results highlight MTL and PFC contributions to temporal memory at the time of encoding and suggest a particular role for the rostrolateral PFC in encoding coarse temporal context.
The protease A Disintegrin And Metalloproteinase 17 (ADAM17) plays a central role in the pathophysiology of several diseases. ADAM17 is involved in the cleavage and shedding of at least 80 known ...membrane-tethered proteins, which subsequently modulate several intracellular signaling pathways, and therefore alter cell behavior. Dysregulated expression and/or activation of ADAM17 has been linked to a wide range of autoimmune and inflammatory diseases, cancer, and cardiovascular disease. In this review, we provide an overview of the current state of knowledge from preclinical models and clinical data on the diverse pathophysiological roles of ADAM17, and discuss the mechanisms underlying ADAM17-mediated protein shedding and the potential therapeutic implications of targeting ADAM17 in these diseases.
Significance Low concentrations of the micronutrient iron in seawater are known to limit primary production and nitrogen fixation in large regions of the global ocean. Thus, it is important to ...constrain the sources and sinks controlling the marine dissolved iron distribution and consequent micronutrient supply to surface plankton. Although the major dissolved iron sources have been historically thought to be atmospheric dust inputs and fluxes from the continental margin, we show here the first data to our knowledge demonstrating that dissolved iron from hydrothermal vents can be transported thousands of kilometers from the venting site, which to date has only been suggested and modeled. Thus, hydrothermal vents must be considered when determining the marine dissolved iron inventory, especially in the abyssal ocean.
Until recently, hydrothermal vents were not considered to be an important source to the marine dissolved Fe (dFe) inventory because hydrothermal Fe was believed to precipitate quantitatively near the vent site. Based on recent abyssal dFe enrichments near hydrothermal vents, however, the leaky vent hypothesis Toner BM, et al. (2012) Oceanography 25(1):209–212 argues that some hydrothermal Fe persists in the dissolved phase and contributes a significant flux of dFe to the global ocean. We show here the first, to our knowledge, dFe (<0.4 µm) measurements from the abyssal southeast and southwest Pacific Ocean, where dFe of 1.0–1.5 nmol/kg near 2,000 m depth (0.4–0.9 nmol/kg above typical deep-sea dFe concentrations) was determined to be hydrothermally derived based on its correlation with primordial ³He and dissolved Mn (dFe: ³He of 0.9–2.7 × 10 ⁶). Given the known sites of hydrothermal venting in these regions, this dFe must have been transported thousands of kilometers away from its vent site to reach our sampling stations. Additionally, changes in the size partitioning of the hydrothermal dFe between soluble (<0.02 µm) and colloidal (0.02–0.4 µm) phases with increasing distance from the vents indicate that dFe transformations continue to occur far from the vent source. This study confirms that although the southern East Pacific Rise only leaks 0.02–1% of total Fe vented into the abyssal Pacific, this dFe persists thousands of kilometers away from the vent source with sufficient magnitude that hydrothermal vents can have far-field effects on global dFe distributions and inventories (≥3% of global aerosol dFe input).
Abstract Background and aims The positive and negative health effects of dietary carbohydrates are of interest to both researchers and consumers. Methods International experts on carbohydrate ...research held a scientific summit in Stresa, Italy, in June 2013 to discuss controversies surrounding the utility of the glycemic index (GI), glycemic load (GL) and glycemic response (GR). Results The outcome was a scientific consensus statement which recognized the importance of postprandial glycemia in overall health, and the GI as a valid and reproducible method of classifying carbohydrate foods for this purpose. There was consensus that diets low in GI and GL were relevant to the prevention and management of diabetes and coronary heart disease, and probably obesity. Moderate to weak associations were observed for selected cancers. The group affirmed that diets low in GI and GL should always be considered in the context of diets otherwise understood as healthy, complementing additional ways of characterizing carbohydrate foods, such as fiber and whole grain content. Diets of low GI and GL were considered particularly important in individuals with insulin resistance. Conclusions Given the high prevalence of diabetes and pre-diabetes worldwide and the consistency of the scientific evidence reviewed, the expert panel confirmed an urgent need to communicate information on GI and GL to the general public and health professionals, through channels such as national dietary guidelines, food composition tables and food labels.
Context.
We report the discovery of TOI 263.01 (TIC 120916706), a transiting substellar object (
R
= 0.87
R
Jup
) orbiting a faint M3.5 V dwarf (
V
= 18.97) on a 0.56 d orbit.
Aims.
We setout to ...determine the nature of the Transiting Exoplanet Survey Satellite (TESS) planet candidate TOI 263.01 using ground-based multicolour transit photometry. The host star is faint, which makes radial-velocity confirmation challenging, but the large transit depth makes the candidate suitable for validation through multicolour photometry.
Methods.
Our analysis combines three transits observed simultaneously in
r
′,
i
′, and
z
s
bands usingthe MuSCAT2 multicolour imager, three LCOGT-observed transit light curves in
g
′,
r
′, and
i
′ bands, a TESS light curve from Sector 3, and a low-resolution spectrum for stellar characterisation observed with the ALFOSC spectrograph. We modelled the light curves with P
Y
T
RANSIT
using a transit model that includes a physics-based light contamination component, allowing us to estimate the contamination from unresolved sources from the multicolour photometry. Using this information we were able to derive the true planet–star radius ratio marginalised over the contamination allowed by the photometry.Combining this with the stellar radius, we were able to make a reliable estimate of the absolute radius of the object.
Results.
The ground-based photometry strongly excludes contamination from unresolved sources with a significant colour difference to TOI 263. Furthermore, contamination from sources of the same stellar type as the host is constrained to levels where the true radius ratio posterior has a median of 0.217 and a 99 percentile of0.286. The median and maximum radius ratios correspond to absolute planet radii of 0.87 and 1.41
R
Jup
, respectively,which confirms the substellar nature of the planet candidate. The object is either a giant planetor a brown dwarf (BD) located deep inside the so-called “brown dwarf desert”. Both possibilities offer a challenge to current planet/BD formation models and make TOI 263.01 an object that merits in-depth follow-up studies.
Abstract We conducted a prospective cohort study investigating the rate and predictors of dissatisfaction among patients after primary total hip arthroplasty (THA). Eight hundred fifty patients were ...assessed preoperatively and 1 year postoperatively using Patient Reported Outcome Measures. There was a 7% rate of dissatisfaction after THA. After univariate analysis, depression, preoperative Short Form 12 mental component score, and symptomatic arthritis of another major joint predicted dissatisfaction at 1 year, but after multivariate analysis, only symptomatic arthritis in another major joint was significant. The development of a major complication did not predict dissatisfaction. Satisfaction also correlates strongly with postoperative functional scores, relief of pain, restoration of function, and success in meeting patient expectations. Pain relief and expectation management are critical in maximizing patient satisfaction after THA.
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