University of New Hampshire

About: University of New Hampshire is a education organization based out in Durham, New Hampshire, United States. It is known for research contribution in the topics: Population & Solar wind. The organization has 9379 authors who have published 24025 publications receiving 1020112 citations. The organization is also known as: UNH.

Holocene radiative forcing impact of northern peatland carbon accumulation and methane emissions

Abstract: Throughout the Holocene, northern peatlands have both accumulated carbon and emitted methane. Their impact on climate radiative forcing has been the net of cooling (persistent CO2 uptake) and warming (persistent CH4 emission). We evaluated this by developing very simple Holocene peatland carbon flux trajectories, and using these as inputs to a simple atmospheric perturbation model. Flux trajectories are based on estimates of contemporary CH4 flux (15–50 Tg CH4 yr−1), total accumulated peat C (250–450 Pg C), and peatland initiation dates. The contemporary perturbations to the atmosphere due to northern peatlands are an increase of ∼100 ppbv CH4 and a decrease of ∼35 ppmv CO2. The net radiative forcing impact northern peatlands is currently about −0.2 to −0.5 W m−2 (a cooling). It is likely that peatlands initially caused a net warming of up to +0.1 W m−2, but have been causing an increasing net cooling for the past 8000–11 000 years. A series of sensitivity simulations indicate that the current radiative forcing impact is determined primarily by the magnitude of the contemporary methane flux and the magnitude of the total C accumulated as peat, and that radiative forcing dynamics during the Holocene depended on flux trajectory, but the overall pattern was similar in all cases.

Ryder Glacier in northwest Greenland is shielded from warm Atlantic water by a bathymetric sill

Abstract: The processes controlling advance and retreat of outlet glaciers in fjords draining the Greenland Ice Sheet remain poorly known, undermining assessments of their dynamics and associated sea-level rise in a warming climate. Mass loss of the Greenland Ice Sheet has increased six-fold over the last four decades, with discharge and melt from outlet glaciers comprising key components of this loss. Here we acquired oceanographic data and multibeam bathymetry in the previously uncharted Sherard Osborn Fjord in northwest Greenland where Ryder Glacier drains into the Arctic Ocean. Our data show that warmer subsurface water of Atlantic origin enters the fjord, but Ryder Glacier’s floating tongue at its present location is partly protected from the inflow by a bathymetric sill located in the innermost fjord. This reduces under-ice melting of the glacier, providing insight into Ryder Glacier’s dynamics and its vulnerability to inflow of Atlantic warmer water. A bathymetric sill in Sherard Osborn Fjord, northwest Greenland shields Ryder Glacier from melting by warm Atlantic water found at the bottom of the fjord, according to high-resolution bathymetric mapping and oceanographic data.

An empirical analysis of the product-process matrix

Abstract: Process choice, a major part of operations strategy, is a key decision that links operations to business strategy. Hayes and Wheelwright, among others, argue that the emphasis given to product customization and other competitive priorities should agree with process choice. Our empirical study investigates whether firms actually link their process choice to product customization and other competitive priorities as hypothesized, and whether compatible decision patterns lead to better performance. Analysis of data collected from managers at 144 U.S. manufacturing plants shows a strong correlation between process choice, product customization, and competitive priorities. Process choice is highly related with the degree of product customization, and also with the emphasis placed on the quality and cost competitive priorities. Job shops and batch shops tend to have more product customization, higher costs, and higher quality. Some continuous flow shops use part commonality and flexible automation to achieve more customization than would otherwise be expected. Without these initiatives, customization in continuous flow shops results in weak performance.

A Second-Generation Genetic Linkage Map of Tilapia (Oreochromis spp.)

Abstract: We constructed a second-generation linkage map of tilapia from the F2 progeny of an interspecific cross between Oreochromis niloticus and Oreochromis aureus. The map reported here contains 525 microsatellite and 21 gene-based markers. It spans 1311 cM in 24 linkage groups, for an average marker spacing of 2.4 cM. We detected associations of sex and red color with markers on linkage group 3. This map will enable mapping and selective breeding of quantitative traits important to the economic culture of tilapia as a food fish and will contribute to the study of closely related cichlids that have undergone explosive adaptive radiation in the lakes of East Africa.

The long-term effects of land-use history on nitrogen cycling in northern hardwood forests

Abstract: Nearly all northeastern U.S. forests have been disturbed by wind, logging, fire, or agriculture over the past several centuries. These disturbances may have long-term impacts on forest carbon and nitrogen cycling, affecting forests' vulnerability to N saturation and their future capacity to store C. We evaluated the long-term (80–110 yr) effects of logging and fire on aboveground biomass, foliar N (%), soil C and N pools, net N mineralization and nitrification, and NO3− leaching in northern hardwood forests in the White Mountain National Forest, New Hampshire. Historical land-use maps were used to identify five areas each containing previously logged, burned, and relatively undisturbed (old-growth) forests. Aboveground biomass averaged 192 Mg/ha on the historically disturbed sites and 261 Mg/ha on the old-growth sites, and species dominance shifted from early- successional and mid-successional species (Betula papyrifera and Acer rubrum) to late-successional species (Fagus grandifolia and particularly A. s...