856 research outputs found
Measurement-driven dynamics for a coherently-excited atom
The phenomenon of telegraphing in a measurement-driven two-level atom was noted in Cresser et al. [Cresser, J.D.; Barnett, S.M.; Jeffers, J.; Pegg, D.T. Opt. Commun. 2006, 264, 352361]. Here we introduce two quantitative measures of telegraphing: one based on the accumulated measurement record and one on the evolution of the quantum state. We use these to analyse the dynamics of the atom over a wide range of parameters. We find, in particular, that the measures provide broadly similar statistics when the measurements are frequent, but differ widely when measurements are sparse. This is in line with intuition, and demonstrates the utility of both measures
Is the angular momentum of an electron conserved in a uniform magnetic field?
We show that an electron moving in a uniform magnetic field possesses a time-varying ``diamagnetic'' angular momentum. Surprisingly this means that the kinetic angular momentum of the electron may vary with time, despite the rotational symmetry of the system. This apparent violation of angular momentum conservation is resolved by including the angular momentum of the surrounding fields
The structure of industry in London: 1775-1825
This study sets out a quantitative overview of the economy of London during the period 1775 to 1825. A database has been constructed from the extant London Fire Office registers of 31,000 businesses trading either in the periods 1769-1777 or 1819- 1825, and in a few cases in both. Represented are over 1300 separate trades covering the entire spectrum of manufacturing, construction, wholesale and retail distribution, transport and the service sector. To complement this data, use has also been made of trade directories, bankruptcy files, trade card collections, Census data and contemporary literature on London trades, including career guides.
In order to analyse trends over this period, the database uses a version of the modern Standard Industrial Classification modified by the author. The 1300 separate trades are grouped into 101 sectors within seven main divisions of the economy. The database includes the name(s) of the proprietors of the business, the address, the trade and details of the risks insured. From this it has been possible to present statistical evidence on a number of areas of controversy about the role of London during the Industrial Revolution. It is shown that London remained a major manufacturing centre throughout the period. It has also been possible to exemplify in detail the impact of the 18th century consumer revolution by charting the expansion and increasing diversity of the wholesale and retail distribution sectors. Finally, the Importance of the role of service industries in the economy of London has been established, with special reference to transport and catering
The structure of industry in London: 1775-1825
This study sets out a quantitative overview of the economy of London during the period 1775 to 1825. A database has been constructed from the extant London Fire Office registers of 31,000 businesses trading either in the periods 1769-1777 or 1819- 1825, and in a few cases in both. Represented are over 1300 separate trades covering the entire spectrum of manufacturing, construction, wholesale and retail distribution, transport and the service sector. To complement this data, use has also been made of trade directories, bankruptcy files, trade card collections, Census data and contemporary literature on London trades, including career guides.
In order to analyse trends over this period, the database uses a version of the modern Standard Industrial Classification modified by the author. The 1300 separate trades are grouped into 101 sectors within seven main divisions of the economy. The database includes the name(s) of the proprietors of the business, the address, the trade and details of the risks insured. From this it has been possible to present statistical evidence on a number of areas of controversy about the role of London during the Industrial Revolution. It is shown that London remained a major manufacturing centre throughout the period. It has also been possible to exemplify in detail the impact of the 18th century consumer revolution by charting the expansion and increasing diversity of the wholesale and retail distribution sectors. Finally, the Importance of the role of service industries in the economy of London has been established, with special reference to transport and catering
High-salinity growth conditions promote tat-independent secretion of tat substrates in Bacillus subtilis
The Gram-positive bacterium Bacillus subtilis contains two Tat translocases, which can facilitate transport of folded proteins across the plasma membrane. Previous research has shown that Tat-dependent protein secretion in B. subtilis is a highly selective process and that heterologous proteins, such as the green fluorescent protein (GFP), are poor Tat substrates in this organism. Nevertheless, when expressed in Escherichia coli, both B. subtilis Tat translocases facilitated exclusively Tat-dependent export of folded GFP when the twin-arginine (RR) signal peptides of the E. coli AmiA, DmsA, or MdoD proteins were attached. Therefore, the present studies were aimed at determining whether the same RR signal peptide-GFP precursors would also be exported Tat dependently in B. subtilis. In addition, we investigated the secretion of GFP fused to the full-length YwbN protein, a strict Tat substrate in B. subtilis. Several investigated GFP fusion proteins were indeed secreted in B. subtilis, but this secretion was shown to be completely Tat independent. At high-salinity growth conditions, the Tat-independent secretion of GFP as directed by the RR signal peptides from the E. coli AmiA, DmsA, or MdoD proteins was significantly enhanced, and this effect was strongest in strains lacking the TatAy-TatCy translocase. This implies that high environmental salinity has a negative influence on the avoidance of Tat-independent secretion of AmiA-GFP, DmsA-GFP, and MdoD-GFP. We conclude that as-yet-unidentified control mechanisms reject the investigated GFP fusion proteins for translocation by the B. subtilis Tat machinery and, at the same time, set limits to their Tat-independent secretion, presumably via the Sec pathway
Practical eDNA sampling methods inferred from particle size distribution and comparison of capture techniques for a Critically Endangered elasmobranch
Environmental DNA (eDNA) methods are increasingly applied in the marine environment to identify species and community structure. To establish widely applicable eDNA techniques for elasmobranchs, we used the Critically Endangered largetooth sawfish (Pristis pristis Linnaeus, 1758) as a model species for: (1) assessing eDNA particle size distribution; (2) assessing the efficiency of long-term preservation of water samples; and (3) comparing the efficiency and detection sensitivity of filtration and precipitation methods. Water samples (1 L) collected from a tank containing one largetooth sawfish specimen were sequentially filtered through five filter membranes of decreasing pore size (20, 10, 5, 1.2, and 0.45 μm). The proportion of sawfish eDNA retained within each size class was determined through quantitative real-time PCR (qPCR) using a species-specific TaqMan probe assay. A linear mixed-effects model (lme) showed that the 1.2 and 20 μm filters captured most of the eDNA particles present in the sampled water. Additionally, whole water samples (0.375 L) were preserved in Longmire's buffer, stored at tropical ambient temperatures (26.3°C ± 3.0 SD) and extracted at five time points: immediately, one, two, and three months after collection, as well as frozen and extracted three months later, to assess the preservation efficiency of Longmire's buffer via qPCR analysis. A linear mixed-effects model showed that samples maintained maximal eDNA yield for at least three months after collection at ambient storage. Lastly, when comparing the filtration and precipitation methods, filtration using 0.45 μm pore size was more sensitive to capture of large-tooth sawfish eDNA than filtration with 20 μm filter or water precipitation. However, water precipitation was more efficient when accounting for volume of water processed. These results provide options for best capture and preservation of elasmobranch eDNA
Efficient glueball simulations on anisotropic lattices
Monte Carlo results for the low-lying glueball spectrum using an improved,
anisotropic action are presented. Ten simulations at lattice spacings ranging
from 0.2 to 0.4 fm and two different anisotropies have been performed in order
demonstrate the advantages of using coarse, anisotropic lattices to calculate
glueball masses. Our determinations of the tensor (2++) and pseudovector (1+-)
glueball masses are more accurate than previous Wilson action calculations.Comment: 43 pages, LaTeX (with revtex). 13 postscript figures. Submitted to
Phys. Rev.
Ingredients of Institutional Reputations and Citizens’ compliance with agency recommendations
The purpose of this study is to examine the link between the reputational components of efficacy and moral reliability of institutions, and citizens' compliance with institutional recommendations. Research on bureaucratic reputations highlights the significance of positive political reputations based on credibility and legitimacy, but the impact of these components is not systematically isolated and studied. We draw insights from political psychology to move beyond a positive-negative valence-based approach of reputation, and highlight the different effect of efficacy and moral reliability components of reputation on citizens' cooperation, engagement in water saving activities, and levels of complaints. We use the Cypriot Water Authority as a case study and inquire how its institutional reputation influences Cypriot citizens' behavior regarding water use. Our data was collected via a representative national survey administered to a random sample of 800 Cypriots in the spring of 2009 and show that favorable perceptions of particular components of institutional reputation shape the levels of satisfaction with specific organizational outputs.</p
The Grail of original meaning : uses of the past in American constitutional theory
Originalist jurisprudence, which enjoins a faithful adherence to the values enshrined in the late eighteenth-century Constitution, has become a prominent feature of contemporary American conservatism. Recovering the original meaning of the Constitution is far from straightforward, and raises major issues of historical interpretation. How far do the assumed historical underpinnings of originalist interpretation mesh with the findings of academic historians? To what extent has the conservative invocation of the Founding Fathers obscured a lost American Enlightenment? Nor is ‘tradition’ in American Constitutional law an unproblematic matter. How far does a desire to restore the original meaning of the Constitution ignore the role of ‘stare decisis’ (precedent) in America's common law heritage? It transpires, moreover, that the various schemes of historical interpretation in American Constitutional jurisprudence do not map easily onto a simple liberal–conservative divide.PostprintPeer reviewe
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