Supporting and protecting device Patent

Supporting and protecting frame structure and plug for empty thrust chamber assembly, handling, and shippin

Bound on the multiplicity of almost complete intersections

Let $R$ be a polynomial ring over a field of characteristic zero and let $I \subset R$ be a graded ideal of height $N$ which is minimally generated by $N+1$ homogeneous polynomials. If $I=(f_1,...,f_{N+1})$ where $f_i$ has degree $d_i$ and $(f_1,...,f_N)$ has height $N$, then the multiplicity of $R/I$ is bounded above by $\prod_{i=1}^N d_i - \max\{1, \sum_{i=1}^N (d_i-1) - (d_{N+1}-1) \}$.Comment: 7 pages; to appear in Communications in Algebr

Symmetric Groups and Quotient Complexity of Boolean Operations

The quotient complexity of a regular language L is the number of left quotients of L, which is the same as the state complexity of L. Suppose that L and L' are binary regular languages with quotient complexities m and n, and that the transition semigroups of the minimal deterministic automata accepting L and L' are the symmetric groups S_m and S_n of degrees m and n, respectively. Denote by o any binary boolean operation that is not a constant and not a function of one argument only. For m,n >= 2 with (m,n) not in {(2,2),(3,4),(4,3),(4,4)} we prove that the quotient complexity of LoL' is mn if and only either (a) m is not equal to n or (b) m=n and the bases (ordered pairs of generators) of S_m and S_n are not conjugate. For (m,n)\in {(2,2),(3,4),(4,3),(4,4)} we give examples to show that this need not hold. In proving these results we generalize the notion of uniform minimality to direct products of automata. We also establish a non-trivial connection between complexity of boolean operations and group theory

Realigning the Clean Water Act: Comprehensive Treatment of Nonpoint Source Pollution

Nonpoint source pollution is the biggest threat to water quality in the United States today. This Article argues for stronger federal controls over nonpoint source pollution. It begins by examining the history of water quality regulation in the United States, including the passage and amendment of the Clean Water Act and the evolving definition of “navigable waters” over time. The Article then discusses recent rulemaking and litigation developments, including the Clean Water Rule, the Navigable Waters Protection Rule, and the County of Maui, Hawaii v. Hawaii Wildlife Fund case. It offers three recommendations. First, the Article calls for a congressional amendment to the Clean Water Act to require binding controls on nonpoint source pollution. Second, recognizing that an amendment to the Clean Water Act may not be politically viable, it offers an approach for controlling nonpoint source pollution through an amendment to the Safe Drinking Water Act. Finally, it identifies tools that interested states, local governments, and citizens’ groups can utilize to take action on nonpoint source pollution under existing law. This Article concludes that reductions in nonpoint source pollution will lead to significant improvements in the water quality of our nation’s lakes, rivers, wetlands, and coastal areas, to the benefit of human and environmental health

Acute pulmonary hypertension caused by tumor embolism: a report of two cases.

Acute pulmonary hypertension leading to right ventricular failure and circulatory collapse is usually caused by thromboembolic obstruction of the pulmonary circulation. However, in rare instances, other causes can be associated with a similar clinical presentation. We present and discuss the clinical histories of two patients with acute right ventricular failure due to an atypical cause of pulmonary hypertension, disseminated pulmonary tumor embolism

Earth Systems Science and Engineering

Providing the essential energy and water systems to support human needs while understanding and addressing their environmental consequences is a watershed problem for the 21st century. The LLNL Earth System Science and Engineering Program seeks to provide the scientific understanding and technological expertise to help provide solutions at both global and regional scales. Our work is highly collaborative with universities, laboratories and industrial partners across the world and involves observational data, laboratory experiments, and numerical simulations. The energy systems we have enjoyed for the last 100 years have resulted in the advanced standard of living in the developed world and a major emerging problem with climate change. Now we face a simultaneous realization that our reliance on fossil fuels is a source of conflict and economic disruption as well as causing potentially abrupt, even catastrophic global climate change. The climate and energy problem is perhaps the greatest challenge ever faced by mankind. Fossil fuel remains the least expensive and most available source of energy and the basis of our economy. The use of fossil fuels, especially over the last 100 years has led to a 30% increase in CO{sub 2} in the atmosphere. The problem is growing. The population of the Earth will increase by several billion people in the next 50 years. If economic growth is to continue, the demand for energy is estimated to approximately double in the next 50 years so that we will need approximately 10 TW more energy than the 15 TW we use now. Much of this demand will come from the developing world where most of the population growth will occur and where advanced energy technology is not generally used. The problem affects and is affected by a complex system of systems. The climate and energy problem will affect resources, social structure and the probability of increased conflict. No one person, no one nation, no one technology can solve the problem. There is no parallel precedent on which to model a solution. On these grounds, we have chosen to tackle four key tasks: (1) Understanding the natural Earth system and anthropogenic systems examining key forcings and processes driving these systems and the interactions between systems; (2) Identify climate change impacts important to society and develop strategies and technologies to adapt to the climate change that is inevitable given past, current, and potential emissions; (3) Developing strategies and technologies to reduce/eliminate greenhouse gas emissions thereby mitigating climate change while generating energy that is economically and socially viable; and (4) Engaging with appropriate economic, legal, social, and political structures to inform key decisions

Conservation Easements: A Tool For Preserving Wildlife Habitat on Private Lands

Conservation easements are an essential tool for conserving private lands, and they have great potential for enhancing wildlife habitat and biodiversity. Private land conservation in the United States is likely to increase in the coming years, in light of Executive Order No. 14,008, issued by President Joseph Biden on January 27, 2021, which set a goal of conserving at least 30% of U.S. lands and waters by 2030 (Executive Office of the President 2021). There is, therefore, a need to evaluate the effect of conservation easements on wildlife habitat and biodiversity and to make recommendations for further enhancing the effectiveness of easements. Herein we propose a shift from primarily negative clauses and restrictive language to a more affirmative approach, developing language to proactively improve management of properties under conservation easement in order to maximize benefits to wildlife and ecosystems. In addition, we identify areas for further research on landowner perceptions and experiences regarding conservation easements

Spatially dispersive finite-difference time-domain analysis of sub-wavelength imaging by the wire medium slabs

In this paper, a spatially dispersive finite-difference time-domain (FDTD) method to model wire media is developed and validated. Sub-wavelength imaging properties of the finite wire medium slabs are examined. It is demonstrated that the slab with its thickness equal to an integer number of half-wavelengths is capable of transporting images with sub-wavelength resolution from one interface of the slab to another. It is also shown that the operation of such transmission devices is not sensitive to their transverse dimensions, which can be made even comparable to the wavelength. In this case, the edge diffractions are negligible and do not disturb the image formation.Comment: 14 pages, 13 figures, submitted to Optics Expres

Quantum walks on quotient graphs

A discrete-time quantum walk on a graph is the repeated application of a unitary evolution operator to a Hilbert space corresponding to the graph. If this unitary evolution operator has an associated group of symmetries, then for certain initial states the walk will be confined to a subspace of the original Hilbert space. Symmetries of the original graph, given by its automorphism group, can be inherited by the evolution operator. We show that a quantum walk confined to the subspace corresponding to this symmetry group can be seen as a different quantum walk on a smaller quotient graph. We give an explicit construction of the quotient graph for any subgroup of the automorphism group and illustrate it with examples. The automorphisms of the quotient graph which are inherited from the original graph are the original automorphism group modulo the subgroup used to construct it. We then analyze the behavior of hitting times on quotient graphs. Hitting time is the average time it takes a walk to reach a given final vertex from a given initial vertex. It has been shown in earlier work [Phys. Rev. A {\bf 74}, 042334 (2006)] that the hitting time can be infinite. We give a condition which determines whether the quotient graph has infinite hitting times given that they exist in the original graph. We apply this condition for the examples discussed and determine which quotient graphs have infinite hitting times. All known examples of quantum walks with fast hitting times correspond to systems with quotient graphs much smaller than the original graph; we conjecture that the existence of a small quotient graph with finite hitting times is necessary for a walk to exhibit a quantum speed-up.Comment: 18 pages, 7 figures in EPS forma