Stream food webs are connected with their riparian zones through cross‐ecosystem movements of energy and nutrients. The use and impact of terrestrial subsidies on aquatic consumers is determined in ...part by in situ biomass of aquatic prey. Thus, stressors such as aquatic pollutants that greatly reduce aquatic secondary production could increase the need for and reliance of stream consumers on terrestrial resource subsidies. To test this hypothesis, we surveyed stream fish, their diets and resource availability in 16 subalpine streams over a regional gradient of trace metals known to strongly impact aquatic insect communities (i.e. fish prey) in the Colorado Rocky Mountains, USA. Fish increased their reliance on terrestrial insect prey as stream metals increased. Relative biomass of terrestrial insects in stomach contents of Brook and Brown Trout increased with respect to aquatic insect biomass and total stomach contents. Drifting insect biomass showed a declining trend for aquatic, but not terrestrial insects, over the metal gradient. Trout densities were unrelated to metal concentrations in streams where we found fish. Synthesis and applications. Our results indicate that diets of aquatic consumers can become more terrestrial as aquatic stressors that limit in situ food production increase and that these subsidies may compensate for loss of aquatic resources. This work implies an important connection between preserving aquatic–terrestrial linkages and management of fish populations in stressed watersheds. Specifically, intact riparian zones and aquatic–terrestrial linkages are likely to be important for maintaining trout production in streams with moderate metal contamination.
Growing political radicalization and polarization in American government has created a scarcity of civilian leadership, knowledge, expertise, and power. Political rivals and adversaries, too busy ...combating each other, have abandoned the helm of the ship of state, setting reason, compromise, intellectual curiosity, and effective governing adrift. A faction of exceptionally capable and influential guardians—America’s military elites—increasingly fill roles in civil society and government intended for competent, democratically elected or political appointed civilian leadership accountable to the American electorate.
Todd Schmidt demonstrates that US military elites play an exceptionally powerful role due to their extraordinary powerful role due to their extraordinary influence over policy process, outcome, and implementation. Through personal interviews with high-ranking national security experts across six presidential administrations, Schmidt concludes that nuanced relationships between military elites, the president, and Congress; decision-making in national security and foreign policy; and the balance of power in civil-military relations suggest a potential trend of praetorian behavior among military elites. A silent coup of the guardians has occurred, and professionals and citizens need to ask what should be done rebalance US civil-military relations.
Jürgen Ehlers developed
frame theory
to better understand the relationship between general relativity and Newtonian gravity. Frame theory contains a parameter
λ
, which can be thought of as 1/
c
2
, ...where
c
is the speed of light. By construction, frame theory is equivalent to general relativity for
λ
> 0, and reduces to Newtonian gravity for
λ
= 0. Moreover, by setting
, frame theory provides a framework to study the Newtonian limit
. A number of ideas relating to frame theory that were introduced by Jürgen have subsequently found important applications to the rigorous study of both the Newtonian limit and post-Newtonian expansions. In this article, we review frame theory and discuss, in a non-technical fashion, some of the rigorous results on the Newtonian limit and post-Newtonian expansions that have followed from Jürgen’s work.
Understanding U.S. national security and foreign policy decision-making requires understanding the actors in the process. Extant scholarship examines the role and behavior of the President; influence ...of civilian elites, advisors, bureaucracies, and institutions; and, more limitedly, the impact of civil-military relations on policy. There are no investigations, however, into the role and behavior of U.S. military elites, as a well-defined, homogenous group of actors in the policy process. This dissertation contributes to filling this gap. It examines military elites utilizing an exclusive ‘insider academic research’ approach. In a grounded theory methodology, over 100 interviews are conducted with national security elites from the Reagan administration to the present. Elite interviews are conducted with the military, diplomatic corps, intelligence community, academia, think tanks, as well as current and past National Security Council staff and leadership. The findings demonstrate two propositions. First, military elites constitute an epistemic community and, second, as an epistemic community, they play a unique role with exceptional influence over both policy process and outcome. These findings help explain nuanced relationships between military elites, the President, and Congress; decision-making in national security and foreign policy; and civil-military balance of power relations that suggest a potential trend of praetorian behavior among U.S. military elites.
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