On Universality in Human Correspondence Activity

Identifying and modeling patterns of human activity has important ramifications in applications ranging from predicting disease spread to optimizing resource allocation. Because of its relevance and availability, written correspondence provides a powerful proxy for studying human activity. One school of thought is that human correspondence is driven by responses to received correspondence, a view that requires distinct response mechanism to explain e-mail and letter correspondence observations. Here, we demonstrate that, like e-mail correspondence, the letter correspondence patterns of 16 writers, performers, politicians, and scientists are well-described by the circadian cycle, task repetition and changing communication needs. We confirm the universality of these mechanisms by properly rescaling letter and e-mail correspondence statistics to reveal their underlying similarity.Comment: 17 pages, 3 figures, 1 tabl

Solution of the Unanimity Rule on exponential, uniform and scalefree networks: A simple model for biodiversity collapse in foodwebs

We solve the Unanimity Rule on networks with exponential, uniform and scalefree degree distributions. In particular we arrive at equations relating the asymptotic number of nodes in one of two states to the initial fraction of nodes in this state. The solutions for exponential and uniform networks are exact, the approximation for the scalefree case is in perfect agreement with simulation results. We use these solutions to provide a theoretical understanding for experimental data on biodiversity loss in foodwebs, which is available for the three network types discussed. The model allows in principle to estimate the critical value of species that have to be removed from the system to induce its complete collapse.Comment: 4 pages, 3 fig

The Concepts of Reliability and Homogeneity

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67956/2/10.1177_001316445001000103.pd

Linear viscoelastic materials with environmental dependent properties

This study expands on the linear theory of thermo-viscoelasticity to include a larger group of materials and environmental effects. The development rests on the observation that for many materials the creep curve which results from a test at one steady value of an environmental parameter can be mapped onto the creep curve at another value of the environmental parameter by: (1) displacing the curve along the logarithmic time axis, (2) scaling the initial elastic response, and (3) scaling the long term or residual response. A thickwall, environmental-dependent, incompressible, viseoelastic cylinder is analyzed for a material that can be modeled by the proposed mapping. It is found that this mapping can have a profound effect on the resulting stress distributions. Further, using the above mapping a constitutive relationship is developed for transient environmental fields.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33713/1/0000225.pd

Incorporation Of Deepwater Horizon Oil In A Terrestrial Bird

Carbon isotopic evidence revealed Deepwater Horizon (DWH) oil entering coastal planktonic and lower terrestrial food webs. The integration of spilled oil into higher terrestrial trophic levels, however, remains uncertain. Wemeasured radiocarbon (C-14) and stable carbon (C-13) in seaside sparrow (Ammodramus maritimus) feathers and crop contents. Lower C-14 and C-13 values in feathers and crop contents of birds from contaminated areas indicated incorporation of carbon from oil. Our results, although based on a small sample of birds, thus reveal a food-web link between oil exposure and a terrestrial ecosystem. They also suggest that the reduction in reproductive success previously documented in the same population might be due to the (direct) toxic effect of oil exposure, rather than to (indirect) ecological effects. Werecommend future studies test our results by using larger samples of birds from a wider area in order to assess the extent and implications ofDWHoil incorporation into the terrestrial food web

Climate Model Intercomparisons: Preparing for the Next Phase

Since 1995, the Coupled Model Intercomparison Project (CMIP) has coordinated climate model experiments involving multiple international modeling teams. Through CMIP, climate modelers and scientists from around the world have analyzed and compared state-of-the-art climate model simulations to gain insights into the processes, mechanisms, and conswquences of climate variability and climate change

Destabilization of the thermohaline circulation by transient perturbations to the hydrological cycle

We reconsider the problem of the stability of the thermohaline circulation as described by a two-dimensional Boussinesq model with mixed boundary conditions. We determine how the stability properties of the system depend on the intensity of the hydrological cycle. We define a two-dimensional parameters' space descriptive of the hydrology of the system and determine, by considering suitable quasi-static perturbations, a bounded region where multiple equilibria of the system are realized. We then focus on how the response of the system to finite-amplitude surface freshwater forcings depends on their rate of increase. We show that it is possible to define a robust separation between slow and fast regimes of forcing. Such separation is obtained by singling out an estimate of the critical growth rate for the anomalous forcing, which can be related to the characteristic advective time scale of the system.Comment: 37 pages, 8 figures, submitted to Clim. Dy

Effects of Restoration of Blood Flow on the Development of Aortic Atherosclerosis in ApoE −/− Mice With Unilateral Renal Artery Stenosis

BACKGROUND: Chronic unilateral renal artery stenosis (RAS) causes accelerated atherosclerosis in apolipoprotein E-deficient (ApoE(-/-)) mice, but effects of restoration of renal blood flow on aortic atherosclerosis are unknown. METHODS AND RESULTS: Male ApoE(-/-) mice underwent sham surgery (n=16) or had partial ligation of the right renal artery (n=41) with the ligature being removed 4 days later (D4LR; n=6), 8 days later (D8LR; n=11), or left in place for 90 days (chronic RAS; n=24). Ligature removal at 4 or 8 days resulted in improved renal blood flow, decreased plasma angiotensin II levels, a return of systolic blood pressure to baseline, and increased plasma levels of neutrophil gelatinase associated lipocalin. Chronic RAS resulted in increased lipid staining in the aortic arch (33.2% [24.4, 47.5] vs 11.6% [6.1, 14.2]; P<0.05) and descending thoracic aorta (10.2% [6.4, 25.9] vs 4.9% [2.8, 7.8]; P<0.05), compared to sham surgery. There was an increased amount of aortic arch lipid staining in the D8LR group (22.7% [22.1, 32.7]), compared to sham-surgery, but less than observed with chronic RAS. Lipid staining in the aortic arch was not increased in the D4LR group, and lipid staining in the descending aorta was not increased in either the D8LR or D4LR groups. There was less macrophage expression in infrarenal aortic atheroma in the D4LR and D8LR groups compared to the chronic RAS group. CONCLUSIONS: Restoration of renal blood flow at either 4 or 8 days after unilateral RAS had a beneficial effect on systolic blood pressure, aortic lipid deposition, and atheroma inflammation

Population genetics of seaside Sparrow (Ammodramus maritimus) subspecies along the gulf of Mexico.

Seaside Sparrows (Ammodramus maritimus) along the Gulf of Mexico are currently recognized as four subspecies, including taxa in Florida (A. m. juncicola and A. m. peninsulae) and southern Texas (Ammodramus m. sennetti), plus a widespread taxon between them (A. m. fisheri). We examined population genetic structure of this Gulf Coast clade using microsatellite and mtDNA data. Results of Bayesian analyses (Structure, GeneLand) of microsatellite data from nine locations do not entirely align with current subspecific taxonomy. Ammodramus m. sennetti from southern Texas is significantly differentiated from all other populations, but we found evidence of an admixture zone with A. m. fisheri near Corpus Christi. The two subspecies along the northern Gulf Coast of Florida are significantly differentiated from both A. m. sennetti and A. m. fisheri, but are not distinct from each other. We found a weak signal of isolation by distance within A. m. fisheri, indicating this population is not entirely panmictic throughout its range. Although continued conservation concern is warranted for all populations along the Gulf Coast, A. m. fisheri appears to be more secure than the far smaller populations in south Texas and the northern Florida Gulf Coast. In particular, the most genetically distinct populations, those in Texas south of Corpus Christi, occupy unique habitats within a very small geographic range

Association of CYP2C19*17 Allele and Choice of P2Y12 Inhibitor on Cardiovascular Outcomes Following Percutaneous Coronary Intervention

Introduction: The CYP2C19*17 allele variant is a gain-of-function polymorphism which increases levels of the active metabolite of clopidogrel. Objective: *17 is associated with increased bleeding risk during clopidogrel therapy, but it is unclear whether alternative P2Y12 inhibitors, prasugrel and ticagrelor, produce better clinical outcomes in patients undergoing percutaneous coronary intervention (PCI). Methods: A single-center observational study was conducted in 928 PCI patients who received CYP2C19 testing and dual anti-platelet therapy (DAPT). Risk of major adverse cardiovascular or cerebrovascular events (MACCE) and clinically significant bleeding over 12 months were compared across genotype and DAPT groups by proportional hazards regression. Results: 584 patients were treated with clopidogrel while 344 patients had alternative therapy. In the clopidogrel group, 173 patients were hetero- or homozygous for *17 and 91 patients were hetero- or homozygous for a loss of function allele (LOF; *2 or *3). Patients treated with clopidogrel were older, more commonly female, and more likely to have hypertension, diabetes, and an acute coronary syndrome (ACS) than patients on alternative therapy. There were no differences in MACCE or clinically significant bleeding events in *17 patients treated with clopidogrel compared to alternative therapy in either the total population (p=0.54) or in ACS patients (p=0.98). Patients with LOF alleles were 3.4 times more likely in the total population (p \u3c0.0001) and 6.7 times more likely among ACS patients (p \u3c0.0001) to have MACCE if prescribed clopidogrel compared with alternative therapy. Discussion: *17 patients had equivalent clinical outcomes when treated with clopidogrel or alternative P2Y12 inhibitors