2,201 research outputs found
SHRIMP ion probe zircon geochronology and Sr and Nd isotope geochemistry for southern Longwood Range and Bluff Peninsula intrusive rocks of Southland, New Zealand
Permian–Jurassic ultramafic to felsic intrusive complexes at Bluff Peninsula and in the southern Longwood Range along the Southland coast represent a series of intraoceanic magmatic arcs with ages spanning a time interval of 110 m.y. New SHRIMP U-Pb zircon data for a quartz diorite from the Flat Hill complex, Bluff Peninsula, yield an age of 259 ± 4 Ma, consistent with other geochronological and paleontological evidence confirming a Late Permian age. The new data are consistent with an age of c. 260 Ma for the intrusive rocks of the Brook Street Terrane. SHRIMP U-Pb zircon ages for the southern Longwood Range confirm that intrusions become progressively younger from east to west across the complex. A gabbro at Oraka Point (eastern end of coastal section) has an age of 245 ± 4 Ma and shows virtually no evidence of zircon inheritance. The age is significantly different from that of the Brook Street Terrane intrusives. Zircon ages from the western parts of the section are younger and more varied (203–227 Ma), indicating more complex magmatic histories. A leucogabbro dike from Pahia Point gives the youngest emplacement age of 142 Ma, which is similar to published U-Pb zircon ages for the Anglem Complex and Paterson Group on Stewart Island
The generalized 3-edge-connectivity of lexicographic product graphs
The generalized -edge-connectivity of a graph is a
generalization of the concept of edge-connectivity. The lexicographic product
of two graphs and , denoted by , is an important graph
product. In this paper, we mainly study the generalized 3-edge-connectivity of
, and get upper and lower bounds of .
Moreover, all bounds are sharp.Comment: 14 page
Generation of tooth profile for roots rotor based on virtual linkage associated with Assur group
This article, for the first time, presents the generation of Roots rotor tooth profiles based on an Assur-group-associated
virtual linkage method. Taking the original Roots rotor as an example, structure and geometry of the Roots rotor are
introduced, and based on the principle of inversion, an equivalent virtual linkage is identified for generating dedendum
tooth profile of the rotor. Using linkage decomposition associated with elemental Assur groups, algorithm for computing
the tooth curve is constructed leading to the explicit expression of rotor profile and the corresponding numerical simulation,
verifying the validity of the proposed approach. For demonstration purpose, the virtual linkage method is then
extended to the generation of tooth profiles for the variants of Roots rotors with arc-cycloidal curves and arc-involute
curves. Integrated with computer-aided design, computer-aided engineering and computer-aided manufacturing software
platforms, as well as the three-dimensional printing technology, this article provides an efficient and intuitive approach
for Roots rotor system design, analysis and development
Mass extinctions and supernova explosions
A nearby supernova (SN) explosion could have negatively influenced life on
Earth, maybe even been responsible for mass extinctions. Mass extinction poses
a significant extinction of numerous species on Earth, as recorded in the
paleontologic, paleoclimatic, and geological record of our planet. Depending on
the distance between the Sun and the SN, different types of threats have to be
considered, such as ozone depletion on Earth, causing increased exposure to the
Sun's ultraviolet radiation, or the direct exposure of lethal x-rays. Another
indirect effect is cloud formation, induced by cosmic rays in the atmosphere
which result in a drop in the Earth's temperature, causing major glaciations of
the Earth. The discovery of highly intensive gamma ray bursts (GRBs), which
could be connected to SNe, initiated further discussions on possible
life-threatening events in Earth's history. The probability that GRBs hit the
Earth is very low. Nevertheless, a past interaction of Earth with GRBs and/or
SNe cannot be excluded and might even have been responsible for past extinction
events.Comment: Chapter for forthcoming book: Handbook of Supernovae, P. Murdin and
A. Alsabeti (eds.), Springer International Publishing (in press
Mitigation-driven translocations: are we moving wildlife in the right direction?
Despite rapid growth in the field of reintroduction biology, many lessons learned from scientific research are not being applied to translocations initiated when human land-use conflicts with persistence of a species. Mitigation-driven translocations outnumber and receive better funding than science-based conservation translocations worldwide, yet their conservation benefit is unclear. As mitigation releases are economically motivated, outcomes may diverge greatly from releases designed to serve the biological needs of species. Translocation as a regulatory tool may be ill-fitted to biologically mitigate environmental damage wrought by development. Evidence suggests that many mitigation-driven translocations fail, though application of scientific principles and best-practices could likely increase success. Furthermore, lack of transparency and documentation of outcomes hinder efforts to understand the scope of the problem. If mitigation-driven translocations continue unabated as a part of the growing billion-dollar ecological consulting industry, it is imperative that the scale and effects of these releases are reported and evaluated
A sense of embodiment is reflected in people's signature size
BACKGROUND: The size of a person's signature may reveal implicit information about how the self is perceived although this has not been closely examined. METHODS/RESULTS: We conducted three experiments to test whether increases in signature size can be induced. Specifically, the aim of these experiments was to test whether changes in signature size reflect a person's current implicit sense of embodiment. Experiment 1 showed that an implicit affect task (positive subliminal evaluative conditioning) led to increases in signature size relative to an affectively neutral task, showing that implicit affective cues alter signature size. Experiments 2 and 3 demonstrated increases in signature size following experiential self-focus on sensory and affective stimuli relative to both conceptual self-focus and external (non-self-focus) in both healthy participants and patients with anorexia nervosa, a disorder associated with self-evaluation and a sense of disembodiment. In all three experiments, increases in signature size were unrelated to changes in self-reported mood and larger than manipulation unrelated variations. CONCLUSIONS: Together, these findings suggest that a person's sense of embodiment is reflected in their signature size
Higher Height, Higher Ability: Judgment Confidence as a Function of Spatial Height Perception
Based on grounded cognition theories, the current study showed that judgments about ability were regulated by the subjects' perceptions of their spatial height. In Experiment 1, we found that after seeing the ground from a higher rather than lower floor, people had higher expectations about their performance on a knowledge test and assigned themselves higher rank positions in a peer comparison evaluation. In Experiment 2, we examined the boundary conditions of the spatial height effects and showed that it could still occur even if we employed photos rather than actual building floors to manipulate the perceptions of spatial heights. In addition, Experiment 2 excluded processing style as an explanation for these observations. In Experiment 3, we investigated a potential mechanism for the spatial height effect by manipulating the scale direction in the questionnaire. Consequently, consistent with our representational dependence account, the effect of spatial heights on ability judgments was eliminated when the mental representation of ability was disturbed by a reverse physical representation. These results suggest that people's judgments about their ability are correlated with their spatial perception
Effect of home-based light treatment on persons with dementia and their caregivers
Sleep disorders are problematic for persons with dementia and their family caregivers. This randomized controlled trial with crossover evaluated the effects of an innovative blue-white light therapy on 17 pairs of home-dwelling persons with dementia and their caregivers. Subjects with dementia received blue-white light and control (‘red-yellow’ light) for six weeks separated by a four-week washout. Neither actigraphic nor most self-reported sleep measures significantly differed for subjects with dementia. For caregivers, both sleep and role strain improved. No evidence of retinal light toxicity was observed. Six weeks of modest doses of blue-white light appear to improve sleep in caregivers but not in persons with dementia. Greater or prolonged circadian stimulation may be needed to determine if light is an effective treatment for persons with dementia
Nanoquartz in Late Permian C1 coal and the high incidence of female lung cancer in the Pearl River Origin area: a retrospective cohort study
<p>Abstract</p> <p>Background</p> <p>The Pearl River Origin area, Qujing District of Yunnan Province, has one of the highest female lung cancer mortality rates in China. Smoking was excluded as a cause of the lung cancer excess because almost all women were non-smokers. Crystalline silica embedded in the soot emissions from coal combustion was found to be associated with the lung cancer risk in a geographical correlation study. Lung cancer rates tend to be higher in places where the Late Permian C1 coal is produced. Therefore, we have hypothesized the two processes: C1 coal combustion --> nanoquartz in ambient air --> lung cancer excess in non-smoking women.</p> <p>Methods/Design</p> <p>We propose to conduct a retrospective cohort study to test the hypothesis above. We will search historical records and compile an inventory of the coal mines in operation during 1930–2009. To estimate the study subjects' retrospective exposure, we will reconstruct the historical exposure scenario by burning the coal samples, collected from operating or deserted coal mines by coal geologists, in a traditional firepit of an old house. Indoor air particulate samples will be collected for nanoquartz and polycyclic aromatic hydrocarbons (PAHs) analyses. Bulk quartz content will be quantified by X-ray diffraction analysis. Size distribution of quartz will be examined by electron microscopes and by centrifugation techniques. Lifetime cumulative exposure to nanoquartz will be estimated for each subject. Using the epidemiology data, we will examine whether the use of C1 coal and the cumulative exposure to nanoquartz are associated with an elevated risk of lung cancer.</p> <p>Discussion</p> <p>The high incidence rate of lung cancer in Xuan Wei, one of the counties in the current study area, was once attributed to high indoor air concentrations of PAHs. The research results have been cited for qualitative and quantitative cancer risk assessment of PAHs by the World Health Organization and other agencies. If nanoquartz is found to be the main underlying cause of the lung cancer epidemic in the study area, cancer potency estimates for PAHs by the international agencies based on the lung cancer data in this study setting should then be updated.</p
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