132 research outputs found
Spectral radius and spanning trees of graphs
For integer a spanning -ended-tree is a spanning tree with at
most leaves. Motivated by the closure theorem of Broersma and Tuinstra
[Independence trees and Hamilton cycles, J. Graph Theory 29 (1998) 227--237],
we provide tight spectral conditions to guarantee the existence of a spanning
-ended-tree in a connected graph of order with extremal graphs being
characterized. Moreover, by adopting Kaneko's theorem [Spanning trees with
constraints on the leaf degree, Discrete Appl. Math. 115 (2001) 73--76], we
also present tight spectral conditions for the existence of a spanning tree
with leaf degree at most in a connected graph of order with extremal
graphs being determined, where is an integer
Measuring the regional availability of forest biomass for biofuels and the potential of GHG reduction
Forest biomass is an important resource for producing bioenergy and reducing greenhouse gas (GHG) emissions. The State of Michigan in the United States (U.S.) is one region recognized for its high potential of supplying forest biomass; however, the long-term availability of timber harvests and the associated harvest residues from this area has not been fully explored. In this study time trend analyses was employed for long term timber assessment and developed mathematical models for harvest residue estimation, as well as the implications of use for ethanol. The GHG savings potential of ethanol over gasoline was also modeled. The methods were applied in Michigan under scenarios of different harvest solutions, harvest types, transportation distances, conversion technologies, and higher heating values over a 50-year period. Our results indicate that the study region has the potential to supply 0.75β1.4 Megatonnes (Mt) dry timber annually and less than 0.05 Mt of dry residue produced from these harvests. This amount of forest biomass could generate 0.15β1.01 Mt of ethanol, which contains 0.68β17.32 GJ of energy. The substitution of ethanol for gasoline as transportation fuel has potential to reduce emissions by 0.043β1.09 Mt CO2eq annually. The developed method is generalizable in other similar regions of different countries for bioenergy related analyses
3S-TSE: Efficient Three-Stage Target Speaker Extraction for Real-Time and Low-Resource Applications
Target speaker extraction (TSE) aims to isolate a specific voice from
multiple mixed speakers relying on a registerd sample. Since voiceprint
features usually vary greatly, current end-to-end neural networks require large
model parameters which are computational intensive and impractical for
real-time applications, espetially on resource-constrained platforms. In this
paper, we address the TSE task using microphone array and introduce a novel
three-stage solution that systematically decouples the process: First, a neural
network is trained to estimate the direction of the target speaker. Second,
with the direction determined, the Generalized Sidelobe Canceller (GSC) is used
to extract the target speech. Third, an Inplace Convolutional Recurrent Neural
Network (ICRN) acts as a denoising post-processor, refining the GSC output to
yield the final separated speech. Our approach delivers superior performance
while drastically reducing computational load, setting a new standard for
efficient real-time target speaker extraction.Comment: Accepted to ICASSP 202
2-Morpholino-4-oxo-4,5-dihydroΒthioΒphene-3-carbonitrile
The title compound, C9H10N2O2S, was obtained from the treatment of ethyl 4-cyano-3-hydrΒoxy-5-morpholinothioΒphene-2-carboxylΒate with concentrated HCl. The mean plane of the essentially planar dihydroΒthioΒphene ring is almost orthogonal to the mirror plane of the N-morpholine substituent, making a dihedral angle of 87.2β
(2)Β°
BMCloud: Minimizing Repair Bandwidth and Maintenance Cost in Cloud Storage
To protect data in cloud storage, fault tolerance and efficient recovery become very important. Recent studies have developed numerous solutions based on erasure code techniques to solve this problem using functional repairs. However, there are two limitations to address. The first one is consistency since the Encoding Matrix (EM) is different among clouds. The other one is repairing bandwidth, which is a concern for most of us. We addressed these two problems from both theoretical and practical perspectives. We developed BMCloud, a new low repair bandwidth, low maintenance cost cloud storage system, which aims to reduce repair bandwidth and maintenance cost. The system employs both functional repair and exact repair while it inherits advantages from the both. We propose the JUDGE_STYLE algorithm, which can judge whether the system should adopt exact repair or functional repair. We implemented a networked storage system prototype and demonstrated our findings. Compared with existing solutions, BMCloud can be used in engineering to save repair bandwidth and degrade maintenance significantly
Carvacrol, a Food-Additive, Provides Neuroprotection on Focal Cerebral Ischemia/Reperfusion Injury in Mice
Carvacrol (CAR), a naturally occurring monoterpenic phenol and food additive, has been shown to have antimicrobials, antitumor, and antidepressant-like activities. A previous study demonstrated that CAR has the ability to protect liver against ischemia/reperfusion injury in rats. In this study, we investigated the protective effects of CAR on cerebral ischemia/reperfusion injury in a middle cerebral artery occlusion mouse model. We found that CAR (50 mg/kg) significantly reduced infarct volume and improved neurological deficits after 75 min of ischemia and 24 h of reperfusion. This neuroprotection was in a dose-dependent manner. Post-treatment with CAR still provided protection on infarct volume when it was administered intraperitoneally at 2 h after reperfusion; however, intracerebroventricular post-treatment reduced infarct volume even when the mice were treated with CAR at 6 h after reperfusion. These findings indicated that CAR has an extended therapeutic window, but delivery strategies may affect the protective effects of CAR. Further, we found that CAR significantly decreased the level of cleaved caspase-3, a marker of apoptosis, suggesting the anti-apoptotic activity of CAR. Finally, our data indicated that CAR treatment increased the level of phosphorylated Akt and the neuroprotection of CAR was reversed by a PI3K inhibitor LY-294002, demonstrating the involvement of the PI3K/Akt pathway in the anti-apoptotic mechanisms of CAR. Due to its safety and wide use in the food industry, CAR is a promising agent to be translated into clinical trials
Hormone-Dependent Expression of a Steroidogenic Acute Regulatory Protein Natural Antisense Transcript in MA-10 Mouse Tumor Leydig Cells
Cholesterol transport is essential for many physiological processes, including steroidogenesis. In steroidogenic cells hormone-induced cholesterol transport is controlled by a protein complex that includes steroidogenic acute regulatory protein (StAR). Star is expressed as 3.5-, 2.8-, and 1.6-kb transcripts that differ only in their 3β²-untranslated regions. Because these transcripts share the same promoter, mRNA stability may be involved in their differential regulation and expression. Recently, the identification of natural antisense transcripts (NATs) has added another level of regulation to eukaryotic gene expression. Here we identified a new NAT that is complementary to the spliced Star mRNA sequence. Using 5β² and 3β² RACE, strand-specific RT-PCR, and ribonuclease protection assays, we demonstrated that Star NAT is expressed in MA-10 Leydig cells and steroidogenic murine tissues. Furthermore, we established that human chorionic gonadotropin stimulates Star NAT expression via cAMP. Our results show that sense-antisense Star RNAs may be coordinately regulated since they are co-expressed in MA-10 cells. Overexpression of Star NAT had a differential effect on the expression of the different Star sense transcripts following cAMP stimulation. Meanwhile, the levels of StAR protein and progesterone production were downregulated in the presence of Star NAT. Our data identify antisense transcription as an additional mechanism involved in the regulation of steroid biosynthesis
The dominant Anopheles vectors of human malaria in the Asia-Pacific region: occurrence data, distribution maps and bionomic prΓ©cis
<p>Abstract</p> <p>Background</p> <p>The final article in a series of three publications examining the global distribution of 41 dominant vector species (DVS) of malaria is presented here. The first publication examined the DVS from the Americas, with the second covering those species present in Africa, Europe and the Middle East. Here we discuss the 19 DVS of the Asian-Pacific region. This region experiences a high diversity of vector species, many occurring sympatrically, which, combined with the occurrence of a high number of species complexes and suspected species complexes, and behavioural plasticity of many of these major vectors, adds a level of entomological complexity not comparable elsewhere globally. To try and untangle the intricacy of the vectors of this region and to increase the effectiveness of vector control interventions, an understanding of the contemporary distribution of each species, combined with a synthesis of the current knowledge of their behaviour and ecology is needed.</p> <p>Results</p> <p>Expert opinion (EO) range maps, created with the most up-to-date expert knowledge of each DVS distribution, were combined with a contemporary database of occurrence data and a suite of open access, environmental and climatic variables. Using the Boosted Regression Tree (BRT) modelling method, distribution maps of each DVS were produced. The occurrence data were abstracted from the formal, published literature, plus other relevant sources, resulting in the collation of DVS occurrence at 10116 locations across 31 countries, of which 8853 were successfully geo-referenced and 7430 were resolved to spatial areas that could be included in the BRT model. A detailed summary of the information on the bionomics of each species and species complex is also presented.</p> <p>Conclusions</p> <p>This article concludes a project aimed to establish the contemporary global distribution of the DVS of malaria. The three articles produced are intended as a detailed reference for scientists continuing research into the aspects of taxonomy, biology and ecology relevant to species-specific vector control. This research is particularly relevant to help unravel the complicated taxonomic status, ecology and epidemiology of the vectors of the Asia-Pacific region. All the occurrence data, predictive maps and EO-shape files generated during the production of these publications will be made available in the public domain. We hope that this will encourage data sharing to improve future iterations of the distribution maps.</p
EFCANet: Exposure Fusion Cross-Attention Network for Low-Light Image Enhancement
Image capture devices capture poor-quality images under low-light conditions, and the resulting images have dark areas due to insufficient exposure. Traditional Multiple Exposure Fusion (MEF) methods fuse images with different exposure levels from a global perspective, which often leads to secondary exposure in well-exposed areas of the original image. At the same time, the image sequences with different exposure levels are not sufficient, and the MEF method is limited by the training data and benchmark labels. To address the above problems, this paper proposes an exposure fusion cross-attention network based low-light image enhancement (EFCANet). EFCANet is characterized by recovering normal light images from a single exposure-corrected image. First, the Exposure Image Generator (EIG) is used to estimate the single exposure-corrected image corresponding to the original input image. Then, the color space of the exposure-corrected image and the original input image are converted from RGB to YCbCr, aiming to maintain the balance of brightness and color. Finally, a Cross-Attention Fusion Module (CAFM) is used to fuse the images on the YCbCr color space to achieve image enhancement. We use a single CAFM as a recursive unit, and EFCANet progressively uses four recursive units. The intermediate enhancement results generated by the first recursive unit and the exposure-corrected image of the original input image in YCbCr color space are used as inputs for the second recursive unit. We conducted comparison experiments with 14 state-of-the-art methods on eight publicly available datasets. The experimental results demonstrate that the image quality of EFCANet enhancement is better than other methods
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