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  • Open Access
    Authors: 
    Jimmy A. Irwin; W. Peter Maksym; Gregory R. Sivakoff; Aaron J. Romanowsky; Dacheng Lin; Tyler Speegle; Ian Prado; David T. Mildebrath; Jay Strader; Jifeng Liu; +1 more
    Publisher: Springer Science and Business Media LLC
    Project: NSERC , NSF | Collaborative Research: R... (1515084), NSF | Collaborative Research: R... (1514763), NSF | Black Holes in Globular C... (1308124)

    An X-ray flaring source was found near the galaxy NGC 4697. Two flares were seen, separated by four years. The flux increased by a factor of 90 on a timescale of about one minute. Both flares were very brief. There is no optical counterpart at the position of the flares, but if the source was at the distance of NGC 4697, the luminosities were 10^39 erg/s. Here we report the results of a search of archival X-ray data for 70 nearby galaxies looking for similar such flares. We found two flaring sources in globular clusters or ultra-compact dwarf companions of parent elliptical galaxies. One source flared once to a peak luminosity of 9 x 10^40 erg/s, while the other flared five times to 10^40 erg/s. All of the flare rise times were <1 minute, and they then decayed over about an hour. When not flaring, the sources appear to be normal accreting neutron star or black hole X-ray binaries, but they are located in old stellar populations, unlike the magnetars, anomalous X-ray pulsars or soft gamma repeaters that have repetitive flares of similar luminosities. Published in the Oct 20 2016 issue of Nature

  • Publication . Article . Other literature type . 2013
    Open Access
    Authors: 
    Maimoona A. Zariwala; Heon Yung Gee; Małgorzata Kurkowiak; Dalal A. Al-Mutairi; Margaret W. Leigh; Toby W. Hurd; Rim Hjeij; Sharon D. Dell; Moumita Chaki; Gerard W. Dougherty; +48 more
    Publisher: Elsevier BV
    Countries: France, Croatia, Germany
    Project: NIH | Novel genetics, pathobiol... (5R01DK068306-17), NIH | Identifying all Meckel-li... (1RC4DK090917-01), NIH | Genetic Disorder of Mucoc... (5U54HL096458-14), NIH | Pathogenesis of PCD Lung ... (5R01HL071798-04), WT , NIH | Colorado Clinical and Tra... (3UL1TR000154-05S1)

    Defects of motile cilia cause primary ciliary dyskinesia (PCD), characterized by recurrent respiratory infections and male infertility. Using whole-exome resequencing and high-throughput mutation analysis, we identified recessive biallelic mutations in ZMYND10 in 14 families and mutations in the recently identified LRRC6 in 13 families. We show that ZMYND10 and LRRC6 interact and that certain ZMYND10 and LRRC6 mutations abrogate the interaction between the LRRC6 CS domain and the ZMYND10 C-terminal domain. Additionally, ZMYND10 and LRRC6 colocalize with the centriole markers SAS6 and PCM1. Mutations in ZMYND10 result in the absence of the axonemal protein components DNAH5 and DNALI1 from respiratory cilia. Animal models support the association between ZMYND10 and human PCD, given that zmynd10 knockdown in zebrafish caused ciliary paralysis leading to cystic kidneys and otolith defects and that knockdown in Xenopus interfered with ciliogenesis. Our findings suggest that a cytoplasmic protein complex containing ZMYND10 and LRRC6 is necessary for motile ciliary function. © 2013 The American Society of Human Genetics.

  • Open Access
    Authors: 
    Montserrat Garcia-Closas; Fergus J. Couch; Kyriaki Michailidou; Marjanka K. Schmidt; Mark N. Brook; Nick Orr; Suhn K. Rhie; Elio Riboli; Heather Spencer Feigelson; Loic Le Marchand; +207 more
    Publisher: Springer Nature
    Countries: Netherlands, Ireland, United Kingdom, United Kingdom
    Project: CIHR , NIH | Characterizing Genetic Su... (5U01CA098233-06), NIH | Discovery Expansion and R... (5U19CA148065-04), NIH | Breast &prostate cancer &... (1U01CA098216-01), NIH | Breast &Prostate Cancer &... (1U01CA098758-01), WT , EC | COGS (223175), NIH | Characterizing Genetic Su... (5U01CA098710-06), NIH | Genetic epidemiology of c... (3R01CA122340-03S1)

    Estrogen receptor (ER)-negative tumors represent 20-30% of all breast cancers, with a higher proportion occurring in younger women and women of African ancestry. The etiology and clinical behavior of ER-negative tumors are different from those of tumors expressing ER (ER positive), including differences in genetic predisposition. To identify susceptibility loci specific to ER-negative disease, we combined in a metaanalysis 3 genome-wide association studies of 4,193 ER-negative breast cancer cases and 35,194 controls with a series of 40 follow-up studies (6,514 cases and 41,455 controls), genotyped using a custom Illumina array, iCOGS, developed by the Collaborative Oncological Gene-environment Study (COGS). SNPs at four loci, 1q32.1 (MDM4, P= 2.1 x 10(-12) and LGR6, P = 1.4 x 10(-8)), 2p24.1 (P = 4.6 x 10(-8)) and 16q12.2 (FTO, P = 4.0 x 10(-8)), were associated with ER-negative but not ER-positive breast cancer (P&gt; 0.05). These findings provide further evidence for distinct etiological pathways associated with invasive ER-positive and ER-negative breast cancers.

  • Open Access
    Authors: 
    Elaine Ruth Martyn;
    Publisher: University of New Brunswick Libraries - UNB
    Country: Canada
  • Publication . Conference object . Part of book or chapter of book . 2017
    Open Access English
    Authors: 
    Yu Hao; Zhijie Xu; Jing Wang; Ying Liu; Jiulun Fan;
    Publisher: IEEE
    Country: United Kingdom

    With the purpose of automatic detection of crowd patterns including abrupt and abnormal changes, a novel approach for extracting motion “textures” from dynamic Spatio-Temporal Volume (STV) blocks formulated by live video streams has been proposed. This paper starts from introducing the common approach for STV construction and corresponding Spatio-Temporal Texture (STT) extraction techniques. Next the crowd motion information contained within the random STT slices are evaluated based on the information entropy theory to cull the static background and noises occupying most of the STV spaces. A preprocessing step using Gabor filtering for improving the STT sampling efficiency and motion fidelity has been devised and tested. The technique has been applied on benchmarking video databases for proof-of-concept and performance evaluation. Preliminary results have shown encouraging outcomes and promising potentials for its real-world crowd monitoring and control applications.

  • Closed Access
    Authors: 
    Duan Li; Christopher Wayne Schmidt;
    Publisher: Elsevier BV

    A smooth cost distribution can be a desirable feature in optimal control design when concerning even distribution of control energy and uniform resource allocation. This consideration is formulated in this paper for discrete-time linear systems where a square cost-variation term is attached to a primal quadratic performance index in an additive form. An analytical control law is obtained for the resulting non-linear-quadratic and nonseparable optimal control problem using a multilevel solution scheme. Investigating the trade-off between minimizing the primal quadratic performance index and minimizing the square cost-variation term offers some useful insights into multiobjective design of control systems.

  • Open Access
    Authors: 
    Suping Cai; Liyu Huang; Jia Zou; Longlong Jing; Buzhong Zhai; Gongjun Ji; Karen M von Deneen; Junchan Ren; Aifeng Ren; Alzheimer’s Disease Neuroimaging Initiative;
    Publisher: Public Library of Science (PLoS)
    Project: NIH | Alzheimers Disease Neuroi... (1U01AG024904-01), CIHR , NIH | "MR Morphometrics and Cog... (5K01AG030514-02), NIH | UC Davis Alzheimer's Core... (3P30AG010129-28S1)

    We used resting-state functional magnetic resonance imaging (fMRI) to investigate changes in the thalamus functional connectivity in early and late stages of amnestic mild cognitive impairment. Data of 25 late stages of amnestic mild cognitive impairment (LMCI) patients, 30 early stages of amnestic mild cognitive impairment (EMCI) patients and 30 well-matched healthy controls (HC) were analyzed from the Alzheimer’s disease Neuroimaging Initiative (ADNI). We focused on the correlation between low frequency fMRI signal fluctuations in the thalamus and those in all other brain regions. Compared to healthy controls, we found functional connectivity between the left/right thalamus and a set of brain areas was decreased in LMCI and/or EMCI including right fusiform gyrus (FG), left and right superior temporal gyrus, left medial frontal gyrus extending into supplementary motor area, right insula, left middle temporal gyrus (MTG) extending into middle occipital gyrus (MOG). We also observed increased functional connectivity between the left/right thalamus and several regions in LMCI and/or EMCI including left FG, right MOG, left and right precuneus, right MTG and left inferior temporal gyrus. In the direct comparison between the LMCI and EMCI groups, we obtained several brain regions showed thalamus-seeded functional connectivity differences such as the precentral gyrus, hippocampus, FG and MTG. Briefly, these brain regions mentioned above were mainly located in the thalamo-related networks including thalamo-hippocampus, thalamo-temporal, thalamo-visual, and thalamo-default mode network. The decreased functional connectivity of the thalamus might suggest reduced functional integrity of thalamo-related networks and increased functional connectivity indicated that aMCI patients could use additional brain resources to compensate for the loss of cognitive function. Our study provided a new sight to understand the two important states of aMCI and revealed resting-state fMRI is an appropriate method for exploring pathophysiological changes in aMCI.

  • Publication . Article . Other literature type . Preprint . 2021 . Embargo End Date: 01 Jan 2021
    Open Access
    Authors: 
    Adams, C. B.; Benbow, W.; Finley, J. P.; Cortina, J.; Covino, S.; D'Amico, G.; D'Elia, V.; Da Vela, P.; Dazzi, F.; De Angelis, A.; +313 more
    Publisher: arXiv
    Countries: Spain, Poland, Norway, Italy, Italy, France, France, Netherlands, Spain, Germany ...
    Project: AKA | Intrinsic Very High Energ... (320045), NSERC

    The results of gamma-ray observations of the binary system HESS J0632 + 057 collected during 450 hr over 15 yr, between 2004 and 2019, are presented. Data taken with the atmospheric Cherenkov telescopes H.E.S.S., MAGIC, and VERITAS at energies above 350 GeV were used together with observations at X-ray energies obtained with Swift-XRT, Chandra, XMM-Newton, NuSTAR, and Suzaku. Some of these observations were accompanied by measurements of the H�� emission line. A significant detection of the modulation of the very high-energy gamma-ray fluxes with a period of 316.7 �� 4.4 days is reported, consistent with the period of 317.3 �� 0.7 days obtained with a refined analysis of X-ray data. The analysis of data from four orbital cycles with dense observational coverage reveals short-timescale variability, with flux-decay timescales of less than 20 days at very high energies. Flux variations observed over a timescale of several years indicate orbit-to-orbit variability. The analysis confirms the previously reported correlation of X-ray and gamma-ray emission from the system at very high significance, but cannot find any correlation of optical H�� parameters with fluxes at X-ray or gamma-ray energies in simultaneous observations. The key finding is that the emission of HESS J0632 + 057 in the X-ray and gamma-ray energy bands is highly variable on different timescales. The ratio of gamma-ray to X-ray flux shows the equality or even dominance of the gamma-ray energy range. This wealth of new data is interpreted taking into account the insufficient knowledge of the ephemeris of the system, and discussed in the context of results reported on other gamma-ray binary systems. The astrophysical journal 923(2), 241 (2021). doi:10.3847/1538-4357/ac29b7 Published by Univ., Chicago, Ill. [u.a.]

  • Open Access English
    Authors: 
    Guangzhao Chen; Xia Li; Xiaoping Liu; Yimin Chen; Xun Liang; Jiye Leng; Xiaocong Xu; Weilin Liao; Yue’an Qiu; Qianlian Wu; +1 more
    Publisher: Nature Portfolio

    Despite its small land coverage, urban land and its expansion have exhibited profound impacts on global environments. Here, we present the scenario projections of global urban land expansion under the framework of the shared socioeconomic pathways (SSPs). Our projections feature a fine spatial resolution of 1 km to preserve spatial details. The projections reveal that although global urban land continues to expand rapidly before the 2040s, China and many other Asian countries are expected to encounter substantial pressure from urban population decline after the 2050s. Approximately 50–63% of the newly expanded urban land is expected to occur on current croplands. Global crop production will decline by approximately 1–4%, corresponding to the annual food needs for a certain crop of 122–1389 million people. These findings stress the importance of governing urban land development as a key measure to mitigate its negative impacts on food production. Shared socioeconomic pathways (SSPs) is a crucial scenario describing the potential of future socio-economic development. The authors here investigate long-term effects of various government policies suggested by different SSPs on urban land and reveal the impact of future urban expansion on other land and food production.

  • Publication . Article . Other literature type . 2020
    Open Access
    Authors: 
    Niloofar Gharesi; Mohammad Mehdi Arefi; Roozbeh Razavi-Far; Jafar Zarei; Shen Yin;
    Publisher: Elsevier BV
    Country: Canada

    Abstract In recent years advanced signal processing techniques are used increasingly to excavate the nonstationary vibration signals and extract elemental-fault information. However, managing and analyzing a multicomponent signal mixed with background noise using only a single analysis tool is not a simple task and may lead to low diagnostic accuracy and a delayed diagnosis. This paper introduces a novel intelligent neuro-wavelet based system with high diagnostic accuracy based on nonrecursive variational mode decomposition (VMD) and wavelet-based neural network, which mainly consists of three steps (i.e. feature extraction (FE), dimension reduction (DR), and fault classification). Firstly, the vibration signals are segmented and processed by a novel nonrecursive VMD, which can decompose the nonstationary signals into a series of discrete modes adaptively, to extract informative features from vibration signals. Multi-Class generalized discriminant analysis is then used in the second step that aims to reduce the dimension of the feature set and improve the computational burden by selecting meaningful information and removing redundant features. In the next step, the obtained features vector is fed to a state-of-the-art hierarchical multi-resolution classifier, so-called wavelet neural network (WNN), which possesses the advantages of both wavelet transform and artificial neural networks for the decision-making. Additionally, to evaluate the information extraction capability of VMD, the subsequent DR method and the calculation accuracy of WNN, other state-of-the-art techniques are used in this work. In this regard, the superiority of the proposed approach is also confirmed through an experimental comparison with published works in the literature.

search
Include:
The following results are related to Canada. Are you interested to view more results? Visit OpenAIRE - Explore.
99,742 Research products, page 1 of 9,975
  • Open Access
    Authors: 
    Jimmy A. Irwin; W. Peter Maksym; Gregory R. Sivakoff; Aaron J. Romanowsky; Dacheng Lin; Tyler Speegle; Ian Prado; David T. Mildebrath; Jay Strader; Jifeng Liu; +1 more
    Publisher: Springer Science and Business Media LLC
    Project: NSERC , NSF | Collaborative Research: R... (1515084), NSF | Collaborative Research: R... (1514763), NSF | Black Holes in Globular C... (1308124)

    An X-ray flaring source was found near the galaxy NGC 4697. Two flares were seen, separated by four years. The flux increased by a factor of 90 on a timescale of about one minute. Both flares were very brief. There is no optical counterpart at the position of the flares, but if the source was at the distance of NGC 4697, the luminosities were 10^39 erg/s. Here we report the results of a search of archival X-ray data for 70 nearby galaxies looking for similar such flares. We found two flaring sources in globular clusters or ultra-compact dwarf companions of parent elliptical galaxies. One source flared once to a peak luminosity of 9 x 10^40 erg/s, while the other flared five times to 10^40 erg/s. All of the flare rise times were <1 minute, and they then decayed over about an hour. When not flaring, the sources appear to be normal accreting neutron star or black hole X-ray binaries, but they are located in old stellar populations, unlike the magnetars, anomalous X-ray pulsars or soft gamma repeaters that have repetitive flares of similar luminosities. Published in the Oct 20 2016 issue of Nature

  • Publication . Article . Other literature type . 2013
    Open Access
    Authors: 
    Maimoona A. Zariwala; Heon Yung Gee; Małgorzata Kurkowiak; Dalal A. Al-Mutairi; Margaret W. Leigh; Toby W. Hurd; Rim Hjeij; Sharon D. Dell; Moumita Chaki; Gerard W. Dougherty; +48 more
    Publisher: Elsevier BV
    Countries: France, Croatia, Germany
    Project: NIH | Novel genetics, pathobiol... (5R01DK068306-17), NIH | Identifying all Meckel-li... (1RC4DK090917-01), NIH | Genetic Disorder of Mucoc... (5U54HL096458-14), NIH | Pathogenesis of PCD Lung ... (5R01HL071798-04), WT , NIH | Colorado Clinical and Tra... (3UL1TR000154-05S1)

    Defects of motile cilia cause primary ciliary dyskinesia (PCD), characterized by recurrent respiratory infections and male infertility. Using whole-exome resequencing and high-throughput mutation analysis, we identified recessive biallelic mutations in ZMYND10 in 14 families and mutations in the recently identified LRRC6 in 13 families. We show that ZMYND10 and LRRC6 interact and that certain ZMYND10 and LRRC6 mutations abrogate the interaction between the LRRC6 CS domain and the ZMYND10 C-terminal domain. Additionally, ZMYND10 and LRRC6 colocalize with the centriole markers SAS6 and PCM1. Mutations in ZMYND10 result in the absence of the axonemal protein components DNAH5 and DNALI1 from respiratory cilia. Animal models support the association between ZMYND10 and human PCD, given that zmynd10 knockdown in zebrafish caused ciliary paralysis leading to cystic kidneys and otolith defects and that knockdown in Xenopus interfered with ciliogenesis. Our findings suggest that a cytoplasmic protein complex containing ZMYND10 and LRRC6 is necessary for motile ciliary function. © 2013 The American Society of Human Genetics.

  • Open Access
    Authors: 
    Montserrat Garcia-Closas; Fergus J. Couch; Kyriaki Michailidou; Marjanka K. Schmidt; Mark N. Brook; Nick Orr; Suhn K. Rhie; Elio Riboli; Heather Spencer Feigelson; Loic Le Marchand; +207 more
    Publisher: Springer Nature
    Countries: Netherlands, Ireland, United Kingdom, United Kingdom
    Project: CIHR , NIH | Characterizing Genetic Su... (5U01CA098233-06), NIH | Discovery Expansion and R... (5U19CA148065-04), NIH | Breast &prostate cancer &... (1U01CA098216-01), NIH | Breast &Prostate Cancer &... (1U01CA098758-01), WT , EC | COGS (223175), NIH | Characterizing Genetic Su... (5U01CA098710-06), NIH | Genetic epidemiology of c... (3R01CA122340-03S1)

    Estrogen receptor (ER)-negative tumors represent 20-30% of all breast cancers, with a higher proportion occurring in younger women and women of African ancestry. The etiology and clinical behavior of ER-negative tumors are different from those of tumors expressing ER (ER positive), including differences in genetic predisposition. To identify susceptibility loci specific to ER-negative disease, we combined in a metaanalysis 3 genome-wide association studies of 4,193 ER-negative breast cancer cases and 35,194 controls with a series of 40 follow-up studies (6,514 cases and 41,455 controls), genotyped using a custom Illumina array, iCOGS, developed by the Collaborative Oncological Gene-environment Study (COGS). SNPs at four loci, 1q32.1 (MDM4, P= 2.1 x 10(-12) and LGR6, P = 1.4 x 10(-8)), 2p24.1 (P = 4.6 x 10(-8)) and 16q12.2 (FTO, P = 4.0 x 10(-8)), were associated with ER-negative but not ER-positive breast cancer (P&gt; 0.05). These findings provide further evidence for distinct etiological pathways associated with invasive ER-positive and ER-negative breast cancers.

  • Open Access
    Authors: 
    Elaine Ruth Martyn;
    Publisher: University of New Brunswick Libraries - UNB
    Country: Canada
  • Publication . Conference object . Part of book or chapter of book . 2017
    Open Access English
    Authors: 
    Yu Hao; Zhijie Xu; Jing Wang; Ying Liu; Jiulun Fan;
    Publisher: IEEE
    Country: United Kingdom

    With the purpose of automatic detection of crowd patterns including abrupt and abnormal changes, a novel approach for extracting motion “textures” from dynamic Spatio-Temporal Volume (STV) blocks formulated by live video streams has been proposed. This paper starts from introducing the common approach for STV construction and corresponding Spatio-Temporal Texture (STT) extraction techniques. Next the crowd motion information contained within the random STT slices are evaluated based on the information entropy theory to cull the static background and noises occupying most of the STV spaces. A preprocessing step using Gabor filtering for improving the STT sampling efficiency and motion fidelity has been devised and tested. The technique has been applied on benchmarking video databases for proof-of-concept and performance evaluation. Preliminary results have shown encouraging outcomes and promising potentials for its real-world crowd monitoring and control applications.

  • Closed Access
    Authors: 
    Duan Li; Christopher Wayne Schmidt;
    Publisher: Elsevier BV

    A smooth cost distribution can be a desirable feature in optimal control design when concerning even distribution of control energy and uniform resource allocation. This consideration is formulated in this paper for discrete-time linear systems where a square cost-variation term is attached to a primal quadratic performance index in an additive form. An analytical control law is obtained for the resulting non-linear-quadratic and nonseparable optimal control problem using a multilevel solution scheme. Investigating the trade-off between minimizing the primal quadratic performance index and minimizing the square cost-variation term offers some useful insights into multiobjective design of control systems.

  • Open Access
    Authors: 
    Suping Cai; Liyu Huang; Jia Zou; Longlong Jing; Buzhong Zhai; Gongjun Ji; Karen M von Deneen; Junchan Ren; Aifeng Ren; Alzheimer’s Disease Neuroimaging Initiative;
    Publisher: Public Library of Science (PLoS)
    Project: NIH | Alzheimers Disease Neuroi... (1U01AG024904-01), CIHR , NIH | "MR Morphometrics and Cog... (5K01AG030514-02), NIH | UC Davis Alzheimer's Core... (3P30AG010129-28S1)

    We used resting-state functional magnetic resonance imaging (fMRI) to investigate changes in the thalamus functional connectivity in early and late stages of amnestic mild cognitive impairment. Data of 25 late stages of amnestic mild cognitive impairment (LMCI) patients, 30 early stages of amnestic mild cognitive impairment (EMCI) patients and 30 well-matched healthy controls (HC) were analyzed from the Alzheimer’s disease Neuroimaging Initiative (ADNI). We focused on the correlation between low frequency fMRI signal fluctuations in the thalamus and those in all other brain regions. Compared to healthy controls, we found functional connectivity between the left/right thalamus and a set of brain areas was decreased in LMCI and/or EMCI including right fusiform gyrus (FG), left and right superior temporal gyrus, left medial frontal gyrus extending into supplementary motor area, right insula, left middle temporal gyrus (MTG) extending into middle occipital gyrus (MOG). We also observed increased functional connectivity between the left/right thalamus and several regions in LMCI and/or EMCI including left FG, right MOG, left and right precuneus, right MTG and left inferior temporal gyrus. In the direct comparison between the LMCI and EMCI groups, we obtained several brain regions showed thalamus-seeded functional connectivity differences such as the precentral gyrus, hippocampus, FG and MTG. Briefly, these brain regions mentioned above were mainly located in the thalamo-related networks including thalamo-hippocampus, thalamo-temporal, thalamo-visual, and thalamo-default mode network. The decreased functional connectivity of the thalamus might suggest reduced functional integrity of thalamo-related networks and increased functional connectivity indicated that aMCI patients could use additional brain resources to compensate for the loss of cognitive function. Our study provided a new sight to understand the two important states of aMCI and revealed resting-state fMRI is an appropriate method for exploring pathophysiological changes in aMCI.

  • Publication . Article . Other literature type . Preprint . 2021 . Embargo End Date: 01 Jan 2021
    Open Access
    Authors: 
    Adams, C. B.; Benbow, W.; Finley, J. P.; Cortina, J.; Covino, S.; D'Amico, G.; D'Elia, V.; Da Vela, P.; Dazzi, F.; De Angelis, A.; +313 more
    Publisher: arXiv
    Countries: Spain, Poland, Norway, Italy, Italy, France, France, Netherlands, Spain, Germany ...
    Project: AKA | Intrinsic Very High Energ... (320045), NSERC

    The results of gamma-ray observations of the binary system HESS J0632 + 057 collected during 450 hr over 15 yr, between 2004 and 2019, are presented. Data taken with the atmospheric Cherenkov telescopes H.E.S.S., MAGIC, and VERITAS at energies above 350 GeV were used together with observations at X-ray energies obtained with Swift-XRT, Chandra, XMM-Newton, NuSTAR, and Suzaku. Some of these observations were accompanied by measurements of the H�� emission line. A significant detection of the modulation of the very high-energy gamma-ray fluxes with a period of 316.7 �� 4.4 days is reported, consistent with the period of 317.3 �� 0.7 days obtained with a refined analysis of X-ray data. The analysis of data from four orbital cycles with dense observational coverage reveals short-timescale variability, with flux-decay timescales of less than 20 days at very high energies. Flux variations observed over a timescale of several years indicate orbit-to-orbit variability. The analysis confirms the previously reported correlation of X-ray and gamma-ray emission from the system at very high significance, but cannot find any correlation of optical H�� parameters with fluxes at X-ray or gamma-ray energies in simultaneous observations. The key finding is that the emission of HESS J0632 + 057 in the X-ray and gamma-ray energy bands is highly variable on different timescales. The ratio of gamma-ray to X-ray flux shows the equality or even dominance of the gamma-ray energy range. This wealth of new data is interpreted taking into account the insufficient knowledge of the ephemeris of the system, and discussed in the context of results reported on other gamma-ray binary systems. The astrophysical journal 923(2), 241 (2021). doi:10.3847/1538-4357/ac29b7 Published by Univ., Chicago, Ill. [u.a.]

  • Open Access English
    Authors: 
    Guangzhao Chen; Xia Li; Xiaoping Liu; Yimin Chen; Xun Liang; Jiye Leng; Xiaocong Xu; Weilin Liao; Yue’an Qiu; Qianlian Wu; +1 more
    Publisher: Nature Portfolio

    Despite its small land coverage, urban land and its expansion have exhibited profound impacts on global environments. Here, we present the scenario projections of global urban land expansion under the framework of the shared socioeconomic pathways (SSPs). Our projections feature a fine spatial resolution of 1 km to preserve spatial details. The projections reveal that although global urban land continues to expand rapidly before the 2040s, China and many other Asian countries are expected to encounter substantial pressure from urban population decline after the 2050s. Approximately 50–63% of the newly expanded urban land is expected to occur on current croplands. Global crop production will decline by approximately 1–4%, corresponding to the annual food needs for a certain crop of 122–1389 million people. These findings stress the importance of governing urban land development as a key measure to mitigate its negative impacts on food production. Shared socioeconomic pathways (SSPs) is a crucial scenario describing the potential of future socio-economic development. The authors here investigate long-term effects of various government policies suggested by different SSPs on urban land and reveal the impact of future urban expansion on other land and food production.

  • Publication . Article . Other literature type . 2020
    Open Access
    Authors: 
    Niloofar Gharesi; Mohammad Mehdi Arefi; Roozbeh Razavi-Far; Jafar Zarei; Shen Yin;
    Publisher: Elsevier BV
    Country: Canada

    Abstract In recent years advanced signal processing techniques are used increasingly to excavate the nonstationary vibration signals and extract elemental-fault information. However, managing and analyzing a multicomponent signal mixed with background noise using only a single analysis tool is not a simple task and may lead to low diagnostic accuracy and a delayed diagnosis. This paper introduces a novel intelligent neuro-wavelet based system with high diagnostic accuracy based on nonrecursive variational mode decomposition (VMD) and wavelet-based neural network, which mainly consists of three steps (i.e. feature extraction (FE), dimension reduction (DR), and fault classification). Firstly, the vibration signals are segmented and processed by a novel nonrecursive VMD, which can decompose the nonstationary signals into a series of discrete modes adaptively, to extract informative features from vibration signals. Multi-Class generalized discriminant analysis is then used in the second step that aims to reduce the dimension of the feature set and improve the computational burden by selecting meaningful information and removing redundant features. In the next step, the obtained features vector is fed to a state-of-the-art hierarchical multi-resolution classifier, so-called wavelet neural network (WNN), which possesses the advantages of both wavelet transform and artificial neural networks for the decision-making. Additionally, to evaluate the information extraction capability of VMD, the subsequent DR method and the calculation accuracy of WNN, other state-of-the-art techniques are used in this work. In this regard, the superiority of the proposed approach is also confirmed through an experimental comparison with published works in the literature.