Synthesis of electro-optic modulators for amplitude modulation of light

Electro-optical modulator realizes voltage transfer function in synthesizing birefringent networks. Choice of the voltage transfer function is important, the most satisfactory optimizes the modulator property

Technique developed for measuring transmittance of optical birefringent networks

The transmission characteristics of synthesized optical single-pass and double-pass birefringent networks is obtained by measuring network transmission as a function of network temperature. This technique is most useful for testing those birefringent networks whose bandwidths and periods are very small

An experimental evaluation of error seeding as a program validation technique

A previously reported experiment in error seeding as a program validation technique is summarized. The experiment was designed to test the validity of three assumptions on which the alleged effectiveness of error seeding is based. Errors were seeded into 17 functionally identical but independently programmed Pascal programs in such a way as to produce 408 programs, each with one seeded error. Using mean time to failure as a metric, results indicated that it is possible to generate seeded errors that are arbitrarily but not equally difficult to locate. Examination of indigenous errors demonstrated that these are also arbitrarily difficult to locate. These two results support the assumption that seeded and indigenous errors are approximately equally difficult to locate. However, the assumption that, for each type of error, all errors are equally difficult to locate was not borne out. Finally, since a seeded error occasionally corrected an indigenous error, the assumption that errors do not interfere with each other was proven wrong. Error seeding can be made useful by taking these results into account in modifying the underlying model

Birefringent devices Final report, 8 Mar. 1966 - 8 Mar. 1967

Birefringent devices, lossless double-pass network synthesis, and electro-optical amplitude modulator

Robustness of proxy-based climate field reconstruction methods

We present results from continued investigations into the fidelity of covariance-based climate field reconstruction (CFR) approaches used in proxy-based climate reconstruction. Our experiments employ synthetic “pseudoproxy” data derived from simulations of forced climate changes over the past millennium. Using networks of these pseudoproxy data, we investigate the sensitivity of CFR performance to signal-to-noise ratios, the noise spectrum, the spatial sampling of pseudoproxy locations, the statistical representation of predictors used, and the diagnostic used to quantify reconstruction skill. Our results reinforce previous conclusions that CFR methods, correctly implemented and applied to suitable networks of proxy data, should yield reliable reconstructions of past climate histories within estimated uncertainties. Our results also demonstrate the deleterious impact of a linear detrending procedure performed recently in certain CFR studies and illustrate flaws in some previously proposed metrics of reconstruction skill

Properties of high emittance materials

High emittance coating materials for beryllium, niobium-zirconium compounds, and stainless steel used in spacecraft radiator

Agricultural Exceptionalism and Industrial Animal Food Production: Exploring the Human Rights Nexus

The host of negative effects of animal agriculture on the immediate environment, workers, and local communities are well-documented, yet little is known about the global repercussions of animal agriculture, especially on human rights guarantees. This contribution attempts to begin filling this soaring gap. It examines the nexus between industrial animal agriculture (with a focus on concentrated animal feeding operations (CAFOs)) on the one hand, and specific international human rights violations on the other hand. Our emphasis is on the role of government in producing these violations, rather than on the agribusiness itself. Laws originally designed to govern small family farms—so-called “farmers’ rights” laws, including right-to-farm laws and exemptions from environmental and animal law—now protect corporate giants, many of which are multinationals. Governments enacting and upholding farmers’ rights shield agribusiness activities that are damaging to the environment and humans’ livelihoods from regulation. While they are prima facie at liberty to do so under domestic law, their laws are subject to the scrutiny of international law, particularly the human rights regime that promises to put a halt to the ongoing insulation of animal agriculture. The human rights perspective adds valuable dynamics to the ongoing debate, is novel in application to the issue, and opens new pathways for academic inquiries and legal strategies because—unlike nuisance laws, environmental laws, and animal protection laws, which de facto exempt the issue from judicial scrutiny—these laws can be used to hold governments accountable. The human rights discourse also gives rise to community empowerment and innovative forms of advocacy and forges connections between the different social justice issues implicated in animal agriculture. Finally, we show how scholars, researchers, stakeholders, and the public concerned about human rights issues can bring animal agriculture into the conversation and prompt their governments to address the issue proactively

Snowbeds are more affected than other subalpine-alpine plant communities by climate change in the Swiss Alps

While the upward shift of plant species has been observed on many alpine and nival summits, the reaction of the subalpine and lower alpine plant communities to the current warming and lower snow precipitation has been little investigated so far. To this aim, 63 old, exhaustive plant inventories, distributed along a subalpine-alpine elevation gradient of the Swiss Alps and covering different plant community types (acidic and calcareous grasslands; windy ridges; snowbeds), were revisited after 25 to 50-years. Old and recent inventories were compared in terms of species diversity with Simpson diversity and Bray-Curtis dissimilarity indices, and in terms of community composition with Principal Component Analysis. Changes in ecological conditions were inferred from the ecological indicator values. The alpha-diversity increased in every plant community, likely because of the arrival of new species. As observed on mountain summits, the new species led to a homogenisation of community compositions. The grasslands were quite stable in terms of species composition, whatever the bedrock type. Indeed, the newly arrived species were part of the typical species pool of the colonised community. In contrast, snowbed communities showed pronounced vegetation changes and a clear shift towards dryer conditions and shorter snow cover, evidenced by their colonisation by species from surrounding grasslands. Longer growing seasons allow alpine grassland species, which are taller and hence more competitive, to colonise the snowbeds. This study showed that subalpine-alpine plant communities reacted differently to the on-going climate changes. Lower snow/rain ratio and longer growing seasons seem to have a higher impact than warming, at least on plant communities dependent on long snow cover. Consequently, they are the most vulnerable to climate change and their persistence in the near future is seriously threatened. Subalpine and alpine grasslands are more stable and, until now, they do not seem to be affected by a warmer climate

Surgery and the spinorial tau-invariant

We associate to a compact spin manifold M a real-valued invariant \tau(M) by taking the supremum over all conformal classes over the infimum inside each conformal class of the first positive Dirac eigenvalue, normalized to volume 1. This invariant is a spinorial analogue of Schoen's $\sigma$-constant, also known as the smooth Yamabe number. We prove that if N is obtained from M by surgery of codimension at least 2, then $\tau(N) \geq \min\{\tau(M),\Lambda_n\}$ with $\Lambda_n>0$. Various topological conclusions can be drawn, in particular that \tau is a spin-bordism invariant below $\Lambda_n$. Below $\Lambda_n$, the values of $\tau$ cannot accumulate from above when varied over all manifolds of a fixed dimension.Comment: to appear in CPD