1,009 research outputs found
History of Whaling and Estimated Kill of Right Whales, Balaena glacialis, in the Northeastern United States, 1620â1924
This study, part of a broader investigation of the history of exploitation of right whales, Balaena glacialis, in the western North Atlantic, emphasizes U.S. shore whaling from Maine to Delaware (from lat. 45°N to 38°30'N) in the period 1620â1924. Our broader study of the entire catch history
is intended to provide an empirical basis for assessing past distribution and abundance of this whale population.
Shore whaling may have begun at Cape Cod, Mass., in the 1620âs or 1630âs; it was certainly underway there by 1668. Right whale catches in New England waters peaked before 1725, and shore whaling at Cape Cod, Marthaâs Vineyard, and Nantucket continued to decline through the rest of the 18th
century. Right whales continued to be taken opportunistically in Massachusetts, however, until the early 20th century. They were hunted in Narragansett Bay, R.I., as early as 1662, and desultory whaling continued in
Rhode Island until at least 1828. Shore whaling in Connecticut may have begun in the middle 1600âs, continuing there until at least 1718. Long Island shore whaling spanned
the period 1650â1924. From its Dutch origins in the 1630âs, a persistent shore whaling enterprise developed in Delaware Bay and along the New Jersey shore. Although this activity was most profi table in New Jersey in the early 1700âs, it continued there until at least the 1820âs. Whaling in all areas of the northeastern United States was seasonal, with most catches in the winter and spring. Historically, right whales appear to have been essentially absent from coastal
waters south of Maine during the summer and autumn.
Based on documented references to specific whale kills, about 750â950 right whales were taken between Maine and Delaware, from 1620 to 1924. Using production statistics
in British customs records, the estimated total secured catch of right whales in New England, New York, and Pennsylvania between 1696 and 1734 was 3,839 whales based on oil and 2,049 based on baleen. After adjusting these totals for hunting loss (loss-rate correction factor = 1.2), we estimate that 4,607 (oil) or 2,459 (baleen) right whales were removed from the stock in this region during the 38-year period 1696â1734. A cumulative catch estimate
of the stockâs size in 1724 is 1,100â1,200. Although recent evidence of occurrence and movements suggests that right whales continue to use their traditional migratory corridor
along the U.S. east coast, the catch history indicates that this stock was much larger in the 1600âs and early 1700âs than it is today. Right whale hunting in the eastern
United States ended by the early 1900âs, and the species has been protected throughout the North Atlantic since the mid 1930âs. Among the possible reasons for the relatively
slow stock recovery are: the very small number of whales that survived the whaling era to become founders, a decline in environmental carrying capacity, and, especially in recent decades, mortality from ship strikes and entanglement in fishing gear
Quantization of setup uncertainties in 3âD dose calculations
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135022/1/mp8756.pd
Environmental Estrogens Induce Mast Cell Degranulation and Enhance IgE-Mediated Release of Allergic Mediators
BACKGROUND: Prevalence and morbidity of allergic diseases have increased over the last decades. Based on the recently recognized differences in asthma prevalence between the sexes, we have examined the effect of endogenous estrogens on a key element of the allergic response. Some lipophilic pollutants have estrogen-like activities and are termed environmental estrogens. These pollutants tend to degrade slowly in the environment and to bioaccumulate and bioconcentrate in the food chain; they also have long biological half-lives. OBJECTIVES: Our goal in this study was to identify possible pathogenic roles for environmental estrogens in the development of allergic diseases. METHODS: We screened a number of environmental estrogens for their ability to modulate the release of allergic mediators from mast cells. We incubated a human mast cell line and primary mast cell cultures derived from bone marrow of wild type and estrogen receptor α (ER-α )âdeficient mice with environmental estrogens with and without estradiol or IgE and allergens. We assessed degranulation of mast cells by quantifying the release of ÎČ -hexosaminidase. RESULTS: All of the environmental estrogens tested caused rapid, dose-related release of ÎČ -hexosaminidase from mast cells and enhanced IgE-mediated release. The combination of physiologic concentrations of 17ÎČ -estradiol and several concentrations of environmental estrogens had additive effects on mast cell degranulation. Comparison of bone marrow mast cells from ER-α âsufficient and ER-α âdeficient mice indicated that much of the effect of environmental estrogens was mediated by ER-α . CONCLUSIONS: Our findings suggest that estrogenic environmental pollutants might promote allergic diseases by inducing and enhancing mast cell degranulation by physiologic estrogens and exposure to allergens
Seasonal Movements of Chinook Salmon in Lake Michigan Based on Tag Recoveries from Recreational Fisheries and Catch Rates in GillâNet Assessments
There are no specific studies of the movements of introduced Chinook salmon Oncorhynchus tshawytscha in Lake Michigan, despite the need for such information for population assessments and stocking allocations. We investigated the seasonal distribution of hatcheryâreared Chinook salmon between May and September based on fisheryâdependent (recoveries from recreational fisheries of fish marked with coded wire tags [CWTs]) and fisheryâindependent sources (catches in assessment gillânet surveys). We modeled recoveries by fishing trips in Michigan waters of Lake Michigan to estimate spatially and temporally explicit abundance indices using generalized linear models (GLMs) and accounted for the efficiency among recovery sources (charter boat captain reports, creel clerk interviews, and headhunter collections of CWT samples from charter boat and nonâcharter boat catches). Recovery levels varied among areas, months, years, and recovery sources, and distribution among areas also varied by month. We used CWT data with lakewide geographical coverage and evaluated the distributions of the absolute numbers of codedâwireâtagged fish recovered in Michigan and Wisconsin waters of Lake Michigan from all possible recovery sources. From both analyses we found that the distribution of Chinook salmon varied seasonally, with displacements from southern areas toward the north from May through summer, from inshore to offshore areas toward the west during summer, and movement back east in the fall. For the analysis of Chinook salmon catch rates in gillânet assessments, we used GLMs to compare levels among months, statistical districts, years, nearshore and offshore areas, and different depths. The temporal and spatial trends were similar to those from the CWT analyses, and the distribution shifted toward deeper waters in July and August. Movement patterns coincided with favorable temperature and prey distribution and were consistent with those exhibited by the Pacific Ocean Chinook salmon population from which the Lake Michigan population originated. Seasonal changes in Chinook salmon distribution influence recreational fisheries, and stocking strategies should consider the influences of movement patterns on fishing opportunities in Lake Michigan.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142273/1/tafs0736.pd
Novel Methods for Ranking District Metered Areas for Water Distribution Network Maintenance Scheduling
Computing and Control for the Water Industry conference 2011 (CCWI 2011), University of Exeter, Exeter, UK, 5 - 7 September 2011To prevent the accumulation of material in pipes which leads to the potential for discolouration events to occur, UK water companies often operate five year cleaning schedules. To organise the schedule District Metered Areas (DMAs), the case study water company assigns a score based on several key performance indicators and water quality levels, which are used to place each DMA into one of three categories: good, poor and urgent. This paper investigates alternative methods of ranking DMAs in order to generate better maintenance schedules. We demonstrate how DMAs can be both partially and totally ordered with methods from multi-objective optimisation, and show how it is possible to prioritise and progressively apply Discolouration Propensity Modelling (DPM) to help guide interventions in the most effective and efficient way. Results obtained from sample DMAs show a good correlation between the DPM scores and the rankings produced by the multiobjective methods. We apply both methods to water networks from a UK water company and demonstrate that used in combination the power index and DPM, have advantages over the current ranking method
Randomized trial of conventional transseptal needle versus radiofrequency energy needle puncture for left atrial access (the TRAVERSE-LA study).
BackgroundTransseptal puncture is a critical step in achieving left atrial (LA) access for a variety of cardiac procedures. Although the mechanical Brockenbrough needle has historically been used for this procedure, a needle employing radiofrequency (RF) energy has more recently been approved for clinical use. We sought to investigate the comparative effectiveness of an RF versus conventional needle for transseptal LA access.Methods and resultsIn this prospective, single-blinded, controlled trial, 72 patients were randomized in a 1:1 fashion to an RF versus conventional (BRK-1) transseptal needle. In an intention-to-treat analysis, the primary outcome was time required for transseptal LA access. Secondary outcomes included failure of the assigned needle, visible plastic dilator shavings from needle introduction, and any procedural complication. The median transseptal puncture time was 68% shorter using the RF needle compared with the conventional needle (2.3 minutes [interquartile range {IQR}, 1.7 to 3.8 minutes] versus 7.3 minutes [IQR, 2.7 to 14.1 minutes], P = 0.005). Failure to achieve transseptal LA access with the assigned needle was less common using the RF versus conventional needle (0/36 [0%] versus 10/36 [27.8%], P < 0.001). Plastic shavings were grossly visible after needle advancement through the dilator and sheath in 0 (0%) RF needle cases and 12 (33.3%) conventional needle cases (P < 0.001). There were no differences in procedural complications (1/36 [2.8%] versus 1/36 [2.8%]).ConclusionsUse of an RF needle resulted in shorter time to transseptal LA access, less failure in achieving transseptal LA access, and fewer visible plastic shavings
In Situ Labeling and Magnetic Resonance Imaging of Transplanted Human Hepatic Stem Cells
The purpose is to address the problem in magnetic resonance imaging (MRI) of contrast agent dilution
Transdimensional physics and inflation
Within the framework of a five-dimensional brane world with a stabilized
radion, we compute the cosmological perturbations generated during inflation
and show that the perturbations are a powerful tool to probe the physics of
extra dimensions. While we find that the power spectrum of scalar perturbations
is unchanged, we show that the existence of the fifth dimension is imprinted on
the spectrum of gravitational waves generated during inflation. In particular,
we find that the tensor perturbations receive a correction proportional to
, where is the Hubble expansion rate during inflation and is
the size of the extra dimension. We also generalize our findings to the case of
several extra dimensions as well as to warped geometries.Comment: RevTeX file, 30 pages, 1 figure. Final version to appear in PR
A method for incorporating organ motion due to breathing into 3D dose calculations
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134856/1/mp8577.pd
- âŠ