7,546 research outputs found
X-ray diffraction analysis of Nb-3Ge and NbGe alloys
Of all the A-15 samples of NbGe alloy examined, DT 094 is unique in that it was at least 99% pure A-15 phase. Also its diffraction peaks were noisy as if there were about a one percent compositional variation on this phase. DT 094, however, was only a large fragment of the drop tube drop, and thus its small sample size may have reduced the intensity, thus enhancing fluctuations enough to explain some of the loss of peak resolution
The association between retinal vein ophthalmodynamometric force change and optic disc excavation
Aim: Retinal vein ophthalmodynamometric force (ODF) is predictive of future optic disc excavation in glaucoma, but it is not known if variation in ODF affects prognosis. We aimed to assess whether a change in ODF provides additional prognostic information. Methods: 135 eyes of 75 patients with glaucoma or being glaucoma suspects had intraocular pressure (IOP), visual fields, stereo optic disc photography and ODF measured on an initial visit and a subsequent visit at mean 82 (SD 7.3) months later. Corneal thickness and blood pressure were recorded on the latter visit. When venous pulsation was spontaneous, the ODF was recorded as 0 g. Change in ODF was calculated. Flicker stereochronoscopy was used to determine the occurrence of optic disc excavation, which was modelled against the measured variables using multiple mixed effects logistic regression. Results: Change in ODF (p=0.046) was associated with increased excavation. Average IOP (p=0.66) and other variables were not associated. Odds ratio for increased optic disc excavation of 1.045 per gram ODF change (95% CI 1.001 to 1.090) was calculated. Conclusion: Change in retinal vein ODF may provide additional information to assist with glaucoma prognostication and implies a significant relationship between venous change and glaucoma patho-physiology
Consumption of Methane and CO_2 by Methanotrophic Microbial Mats from Gas Seeps of the Anoxic Black Sea
The deep anoxic shelf of the northwestern Black Sea has numerous gas seeps, which are populated by methanotrophic microbial mats in and above the seafloor. Above the seafloor, the mats can form tall reef-like structures composed of porous carbonate and microbial biomass. Here, we investigated the spatial patterns of CH_4 and CO_2 assimilation in relation to the distribution of ANME groups and their associated bacteria in mat samples obtained from the surface of a large reef structure. A combination of different methods, including radiotracer incubation, beta microimaging, secondary ion mass spectrometry, and catalyzed reporter deposition fluorescence in situ hybridization, was applied to sections of mat obtained from the large reef structure to locate hot spots of methanotrophy and to identify the responsible microbial consortia. In addition, CO_2 reduction to methane was investigated in the presence or absence of methane, sulfate, and hydrogen. The mat had an average δ^(13)C carbon isotopic signature of −67.1‰, indicating that methane was the main carbon source. Regions dominated by ANME-1 had isotope signatures that were significantly heavier (−66.4‰ ± 3.9 ‰ [mean ± standard deviation; n = 7]) than those of the more central regions dominated by ANME-2 (−72.9‰ ± 2.2 ‰; n = 7). Incorporation of ^(14)C from radiolabeled CH_4 or CO_2 revealed one hot spot for methanotrophy and CO2 fixation close to the surface of the mat and a low assimilation efficiency (1 to 2% of methane oxidized). Replicate incubations of the mat with ^(14)CH_4 or ^(14)CO_2 revealed that there was interconversion of CH_4 and CO_2. The level of CO_2 reduction was about 10% of the level of anaerobic oxidation of methane. However, since considerable methane formation was observed only in the presence of methane and sulfate, the process appeared to be a rereaction of anaerobic oxidation of methane rather than net methanogenesis
Varieties of Limited Access Orders: The nexus between politics and economics in hybrid regimes
This article advances our understanding of differences in hybrid stability by going beyond existing regime typologies that separate the study of political institutions from the study of economic institutions. It combines the work of Douglass North, John Wallis, and Barry Weingast (NWW) on varieties of social orders with the literature on political and economic regime typologies and dynamics to understand hybrid regimes as Limited Access Orders (LAOs) that differ in the way dominant elites limit access to political and economic resources. Based on a measurement of political and economic access applied to seven post‐Soviet states, the article identifies four types of LAOs. Challenging NWW's claim, it shows that hybrid regimes can combine different degrees of political and economic access to sustain stability. Our typology allows to form theoretical expectations about the kinds of political and/or economic changes that will move different types of LAOs toward more openness or closure
The Apparent Involvement of ANMEs in Mineral Dependent Methane Oxidation, as an Analog for Possible Martian Methanotrophy
On Earth, marine anaerobic methane oxidation (AOM) can be driven by the
microbial reduction of sulfate, iron, and manganese. Here, we have further characterized
marine sediment incubations to determine if the mineral dependent methane oxidation
involves similar microorganisms to those found for sulfate-dependent methane oxidation.
Through FISH and FISH-SIMS analyses using ^(13)C and ^(15)N labeled substrates, we find that
the most active cells during manganese dependent AOM are primarily mixed and
mixed-cluster aggregates of archaea and bacteria. Overall, our control experiment using
sulfate showed two active bacterial clusters, two active shell aggregates, one active mixed
aggregate, and an active archaeal sarcina, the last of which appeared to take up methane in
the absence of a closely-associated bacterial partner. A single example of a shell aggregate
appeared to be active in the manganese incubation, along with three mixed aggregates and
an archaeal sarcina. These results suggest that the microorganisms (e.g., ANME-2) found
active in the manganese-dependent incubations are likely capable of sulfate-dependent
AOM. Similar metabolic flexibility for Martian methanotrophs would mean that the same
microbial groups could inhabit a diverse set of Martian mineralogical crustal environments.
The recently discovered seasonal Martian plumes of methane outgassing could be coupled
to the reduction of abundant surface sulfates and extensive metal oxides, providing a feasible metabolism for present and past Mars. In an optimistic scenario Martian
methanotrophy consumes much of the periodic methane released supporting on the order
of 10,000 microbial cells per cm2 of Martian surface. Alternatively, most of the methane
released each year could be oxidized through an abiotic process requiring biological
methane oxidation to be more limited. If under this scenario, 1% of this methane flux were
oxidized by biology in surface soils or in subsurface aquifers (prior to release), a total of
about 10^(20) microbial cells could be supported through methanotrophy with the cells
concentrated in regions of methane release
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[Abstract] Sentencing intoxicated offenders: does alcoholism excuse drunkenness?
Criminal responsibility is founded on the volitional control of action, yet many offences are committed whilst intoxicated. Alcohol is a widely-used intoxicant known to impair behavioural control and memory, opening the door to claims of partial or absent responsibility. Criminal law rules have developed to resist such claims. In particular, findings of criminal responsibility in intoxicated offenders frequently call on ‘prior fault’ logic: the intoxicated offender may claim to have been irrational, but culpability can be imported from their earlier, rational choice to consume intoxicants (Robinson, 1985). That drunkenness does not excuse derives from an unforced choice to become drunk. Yet this raises questions over the extent to which an alcoholic’s choice to drink is unforced. Current neurobiological models of addiction stress compulsion as a primary component, bringing into question the volitional nature of continued consumption (Volkow & Fowler, 2000; Dalley, Everitt, & Robbins, 2011). At the same time, some legal scholars have noted that the potentially fatal nature of alcoholic withdrawal could likewise undermine suggestion that consumption is voluntary, drawing analogy to a defence of duress where actions have been forced under the threat of death (Husak, 1999; Yaffe, 2013). We asked 290 UK Magistrates to consider a criminal sentencing scenario in which evidence of a defendant’s state of intoxication at the time of the offence was presented in tandem with information that they were either teetotal, a casual drinker or an alcoholic. We found that intoxication reduced blameworthiness for criminal acts if the offender had no previous experience with alcohol whilst, in direct contrast, intoxication served to aggravate offending if the defendant was an alcoholic. The likelihood of our defendant receiving a reduced sentence was over ten times greater in the event that, though intoxicated, they were not also an alcoholic. Leniency was blocked by alcoholism despite Magistrates’ qualitative responses suggesting its understanding as a generally mitigating factor, revealing a disconnect between expressed opinion and sentencing behaviour in practice. Our results indicate that, far from excusing drunkenness, the state of being an alcoholic is more frequently deemed to aggravate offending, being associated with harsher sentencing even where the offence in question was committed whilst sober
Perceptions of knowledge sharing among small family firm leaders: a structural equation model
Small family firms have many unique relational qualities with implications for how knowledge is passed between individuals. Extant literature posits leadership approach as important in explaining differences in knowledge-sharing climate from one firm to another. This study investigates how leadership approaches interact with family influence to inform perceptions of knowledge sharing. We utilize survey data (n = 110) from owner-managers of knowledge-intensive small family firms in Scotland. Our findings present a choice in leadership intention, contrasting organization-focused participation against family-influenced guidance. Insight is offered on the implications of this leadership choice at both organizational and familial level
GeoZui3D: Data Fusion for Interpreting Oceanographic Data
GeoZui3D stands for Geographic Zooming User Interface. It is a new visualization software system designed for interpreting multiple sources of 3D data. The system supports gridded terrain models, triangular meshes, curtain plots, and a number of other display objects. A novel center of workspace interaction method unifies a number of aspects of the interface. It creates a simple viewpoint control method, it helps link multiple views, and is ideal for stereoscopic viewing. GeoZui3D has a number of features to support real-time input. Through a CORBA interface external entities can influence the position and state of objects in the display. Extra windows can be attached to moving objects allowing for their position and data to be monitored. We describe the application of this system for heterogeneous data fusion, for multibeam QC and for ROV/AUV monitoring
Assessing the UK policies for broadband adoption
Broadband technology has been introduced to the business community and the public as a rapid way of exploiting the Internet. The benefits of its use (fast reliable connections, and always on) have been widely realised and broadband diffusion is one of the items at the top of the agenda for technology related polices of governments worldwide. In this paper an examination of the impact of the UK government’s polices upon broadband adoption is undertaken. Based on institutional theory a consideration of the manipulation of supply push and demand pull forces in the diffusion of broadband is offered. Using primary and secondary data sources, an analysis of the specific institutional actions related to IT diffusion as pursued by the UK government in the case of broadband is provided. Bringing the time dimension into consideration it is revealed that the UK government has shifted its attention from supply push-only strategies to more interventional ones where the demand pull forces are also mobilised. It is believed that this research will assist in the extraction of the “success factors” in government intervention that support the diffusion of technology with a view to render favourable results if applied to other national settings
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