41 research outputs found

    Warming threat compounds habitat degradation impacts on a tropical butterfly community in Vietnam

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    AbstractSpecies are threatened globally by multiple and often synergistic environmental changes including habitat loss, fragmentation and climate change. However, how these changes act in concert is poorly understood, especially in the tropics where the vast majority of biodiversity resides. Here, using a unique dataset covering 10~years of butterfly surveys (2003–2013) at Tam Dao National Park in northern Vietnam, we examined the combined impacts of habitat degradation (following intensive infrastructure development in 2005) and the possible threat of warming (extrapolating upon the relationship between natural climatic variation and community indices) for tropical butterfly communities. We found that both habitat degradation and warmer temperatures led to fewer narrow-range and forest-associated species comprising the sampled communities. Under projected climate change scenarios, the impact of warming was comparable to habitat degradation with respect to community change, and degraded forest communities were projected to shift towards cosmopolitan and non-forest species even more. The tropics have been heavily deforested world-wide and also suffer from heavy impacts of degradation and fragmentation, especially road construction. Warming will compound habitat degradation impacts such that the conservation of tropical biodiversity will require addressing these multiple global changes simultaneously

    The Effect of Swimming Goggles on Intraocular Pressure and Blood Flow within the Optic Nerve Head

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    Purpose: Goggles are frequently worn in the sport of swimming and are designed to form a seal around the periorbital tissue orbit. The resultant pressure on the eye may have the potential to affect intraocular pressure and blood flow of the optic nerve head. This study evaluates the influence of wearing swimming goggles on intraocular pressure (IOP) and blood flow of the ocular nerve head (ONH) in normal subjects. Materials and Methods: Thirty healthy participants took part in this study. The IOP of each participant was measured using a Goldmann tonometer. Measurements were taken immediately before putting on swimming goggles, at 5, 10, 30, and 60 minutes after putting on swimming goggles, and then immediately after taking off the goggles. Blood flow of the ONH was measured using the Heidelberg retinal flowmeter. Results: The average IOP before, during and after wearing the swimming goggles were 11.88 ± 2.82 mmHg, 14.20 ± 2.81 mmHg and 11.78 ± 2.89 mmHg, respectively. The IOP increased immediately after putting on the goggles (p < 0.05) and then returned to normal values immediately after removal (p> 0.05). Blood flow of the ONH was 336.60 ± 89.07 Arbitrary Units (AU) before and 319.18 ± 96.02 AU after the goggles were worn (p < 0.05). Conclusion: A small but significant IOP elevation was observed immediately after the swimming goggles were put on. This elevated IOP was maintained while the goggles were kept on, and then returned to normal levels as soon as they were taken off. Blood flow of the ONH did not change significantly throughout the experiment. These facts should be considered for safety concerns, especially in advanced glaucoma patients

    Engineering new bone tissue in vitro on highly porous poly(Α-hydroxyl acids)/hydroxyapatite composite scaffolds

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    Engineering new bone tissue with cells and a synthetic extracellular matrix (scaffolding) represents a new approach for the regeneration of mineralized tissues compared with the transplantation of bone (autografts or allografts). In the present work, highly porous poly( L -lactic acid) (PLLA) and PLLA/hydroxyapatite (HAP) composite scaffolds were prepared with a thermally induced phase separation technique. The scaffolds were seeded with osteoblastic cells and cultured in vitro . In the pure PLLA scaffolds, the osteoblasts attached primarily on the outer surface of the polymer. In contrast, the osteoblasts penetrated deep into the PLLA/HAP scaffolds and were uniformly distributed. The osteoblast survival percentage in the PLLA/HAP scaffolds was superior to that in the PLLA scaffolds. The osteoblasts proliferated in both types of the scaffolds, but the cell number was always higher in the PLLA/HAP composite scaffolds during 6 weeks of in vitro cultivation. Bone-specific markers (mRNAs encoding bone sialoprotein and osteocalcin) were expressed more abundantly in the PLLA/HAP composite scaffolds than in the PLLA scaffolds. The new tissue increased continuously in the PLLA/HAP composite scaffolds, whereas new tissue formed only near the surface of pure PLLA scaffolds. These results demonstrate that HAP imparts osteoconductivity and the highly porous PLLA/HAP composite scaffolds are superior to pure PLLA scaffolds for bone tissue engineering. © 2000 John Wiley & Sons, Inc. J Biomed Mater Res 54: 284–293, 2001Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34419/1/16_ftp.pd

    Interest-driven creator theory: towards a theory of learning design for Asia in the twenty-first century

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    Asian education is known for its examination-driven orientation, with the downsides of distorting the processes of learning and teaching, diminishing students’ interest in learning, and failing to nurture twenty-first century competencies among students. As a group of Asian researchers, we have been developing Interest-Driven Creator (IDC) Theory, a design theory based on three anchored concepts, namely interest, creation, and habit. Each of these anchored concepts is represented by a loop composed of three components. In the interest loop, the three components are triggering, immersing, and extending. The components of the creation loop are imitating, combining, and staging. The habit loop consists of cuing environment, routine, and harmony. These three loops are interconnected in various ways, with their characteristics revealed by the design process. We hypothesize that technology-supported learning activities that are designed with reference to IDC Theory will enable students to develop interest in learning, be immersed in the creation process, and, by repeating this process in their daily routines, strengthen habits of creation. Furthermore, students will excel in learning performance, develop twenty-first century competencies, and become lifelong interest-driven creators. To sharpen our understanding and further the development of the theory, we need more discussion and collaborative efforts in the community. Hypotheses arising from this theory can be tested, revised, or refined by setting up and investigating IDC Theory-based experimental sites. By disseminating the framework, foundations, and practices to the various countries and regions of Asia, we hope that it will bring about compelling examples and hence a form of quality education for the twenty-first century, which is an alternative to the examination-driven education system. In this paper, we present an overall introduction to IDC Theory and its history, and discuss some of the steps for advancing it in the future

    Ultralight vector dark matter search using data from the KAGRA O3GK run

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    Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

    Observation of gravitational waves from the coalescence of a 2.5−4.5 M⊙ compact object and a neutron star

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    Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

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    Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

    Theoretical study of the intrinsic reactivities of various allylmetals toward carbonyls and water

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    Quantum mechanics MP2/6-31+G{*} calculations have been carried out for the reactions of a series of monomeric allylmetals with water and carbonyl compounds in the gas phase. Allyl complexes of groups IA and IIA and low-valent group IIIA and IVA metals are pi-complexes or reactive a-complexes. They show high reactivities toward hydrolysis. Group IIB, trivalent group IIIA, tetravalent group IVA, and both tri- and pentavalent group VA metals form a-complexes with allyl. These allylmetals are less reactive toward hydrolysis than toward allylation. The calculated intrinsic kinetic preference of allylation over hydrolysis is found to correlate well with the reactivity of hydrolysis, the nucleophilicity of the allylmetals, and the lateness of hydrolysis transition structures. Both the nucleophilicity of the allylmetal complexes and the thermodynamic driving force are important to the reactivity of hydrolysis. Importantly, there is a large thermodynamic preference for allylation over hydrolysis for all allylmetals because the hydrolysis has to break a strong O-H bond. Thus, the kinetic preference for allylation is correlated with the degree of H-O bond breaking in the hydrolysis transition structure

    The Observation of Complications after General Anesthesia

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