Unexpected phase locking of magnetic fluctuations in the multi-k magnet USb

The spin waves in the multi-k antiferromagnet USb soften and become quasielastic well below the antiferromagnetic ordering temperature TN. This occurs without a magnetic or structural transition. It has been suggested that this change is in fact due to dephasing of the different multi-k components: a switch from 3-k to 1-k behavior. In this work, we use inelastic neutron scattering with tridirectional polarization analysis to probe the quasielastic magnetic excitations and reveal that the 3-k structure does not dephase. More surprisingly, the paramagnetic correlations also maintain the same clear phase correlations well above TN (up to at least 1.4TN)

Materials and processes control for space applications

Materials and processes control relative to space applications is discussed. The components of a total material and process control system are identified, contamination control issues are listed, and recommendations are made

A hilbert-style axiomatisation for equational hybrid logic

This paper introduces an axiomatisation for equational hybrid logic based on previous axiomatizations and natural deduction systems for propositional and first-order hybrid logic. Its soundness and completeness is discussed. This work is part of a broader research project on the development a general proof calculus for hybrid logics

Antennal arnpullary glands of Helicoverpa zea (Lepidoptera : Noctuidae)

In adult moths, the cephalic aorta terminates in an apical sack from which extends a pair of optic and antennal vessels that lie on either side of the esophagus, at the dorsoanterior surface of the brain. The base of each antennal vessel is dilated to form an ampulla that contains an oval mass of tissue, the antennal ampullary gland (AAG). An ultrastructural study revealed that the AAG of the corn earworm moth, Helicoverpa zea (Lepidoptera, Noctuidae), is composed of a single type of 40-50 parenchymal cells that produce secretory granules. The secretory material is released into the lymph channel of the ampullary vessel, suggesting that the AAG is an endocrine gland. Unlike the prothoracic gland and the corpus allatum, the AAG does not receive direct neural innervation; however, portions of the aortal muscle, associated with the ampullary wall, contain neurosecretory terminals and some of their products may also affect the AAG. No morphological differences were found between the AAG of males and females, with the exception that the glands in males were slightly larger. The function of the AAG remains unknown at this time. Because the AAG is located within the ampulla of the antennal vessel, one could assume that the product(s) of this gland may influence the response of the antennal sensory neurons to external stimuli

Spectroscopic and redox properties of amine-unctionalized K_2[Os-^(II)(bpy)(CN)_4] complexes

We report the first examples of amine-functionalized K_2[Os^(II)(bpy)(CN)_4] (bpy = 2,2'-bipyridine) complexes. The tetracyanoosmate complexes were prepared by UV irradiation (λ = 254 nm) of K_4[Os^(II)(CN)_6] and primary amine-functionalized bpy ligands in acidic aqueous media. The aqueous solution pH dependences of the spectroscopic and redox properties of 4,4'- and 5,5'-substituted complexes have been investigated. The pendant amine functional groups and coordinated cyanide ligands are basic sites that can be sequentially protonated, thereby allowing systematic tuning of electrochemical and optical spectroscopic properties

From subsistence farming to agribusiness and nonfarm entrepreneurship: Does it improve economic conditions and well-being?

To eradicate poverty, governments across developing countries have adopted programs to promote business ownership, with varying levels of success. The mixed success of such programs underscores the importance of local business and economic conditions. Yet, empirical evidence on how local context shapes outcomes of entrepreneurship-focused poverty initiatives is sparse. In this paper, we use data from the 2015 Smallholder Survey to examine the impact of farming as a business (agribusiness) and nonfarm entrepreneurship (NFE) on household income and economic well-being in Uganda. We find that, in comparison to subsistence farming, engaging in agribusiness and NFE boosts household income and economic well-being, especially in rural areas with high poverty rates. Our research contributes to the literature by offering new evidence on the efficacy of entrepreneurial initiatives in the specific context of a developing country with a large rural and agricultural economy. In terms of policy, our analysis provides support for the promotion of agribusiness and NFE initiatives to reduce poverty and overcome disparities between urban and rural settings

Charged particle motion and radiation in strong electromagnetic fields

The dynamics of charged particles in electromagnetic fields is an essential component of understanding the most extreme environments in our Universe. In electromagnetic fields of sufficient magnitude, radiation emission dominates the particle motion and effects of nonlinear quantum electrodynamics (QED) are crucial, which triggers electron-positron pair cascades and counterintuitive particle-trapping phenomena. As a result of recent progress in laser technology, high-power lasers provide a platform to create and probe such fields in the laboratory. With new large-scale laser facilities on the horizon and the prospect of investigating these hitherto unexplored regimes, we review the basic physical processes of radiation reaction and QED in strong fields, how they are treated theoretically and in simulation, the new collective dynamics they unlock, recent experimental progress and plans, as well as possible applications for high-flux particle and radiation sources.Comment: 62 pages, 35 figures; as submitted to Rev. Mod. Phy

Fermi-surface topology of the iron pnictide LaFe2_2P2_2

We report on a comprehensive de Haas--van Alphen (dHvA) study of the iron pnictide LaFe$_2$P$_2$. Our extensive density-functional band-structure calculations can well explain the measured angular-dependent dHvA frequencies. As salient feature, we observe only one quasi-two-dimensional Fermi-surface sheet, i.e., a hole-like Fermi-surface cylinder around $\Gamma$, essential for $s_\pm$ pairing, is missing. In spite of considerable mass enhancements due to many-body effects, LaFe$_2$P$_2$ shows no superconductivity. This is likely caused by the absence of any nesting between electron and hole bands.Comment: 5 pages, 4 figure