Every application in a smart city environment like the smart grid,health monitoring, security, and surveillance generates non-stationary datastreams. Due to such nature, the statistical properties of data changes over...Every application in a smart city environment like the smart grid,health monitoring, security, and surveillance generates non-stationary datastreams. Due to such nature, the statistical properties of data changes overtime, leading to class imbalance and concept drift issues. Both these issuescause model performance degradation. Most of the current work has beenfocused on developing an ensemble strategy by training a new classifier on thelatest data to resolve the issue. These techniques suffer while training the newclassifier if the data is imbalanced. Also, the class imbalance ratio may changegreatly from one input stream to another, making the problem more complex.The existing solutions proposed for addressing the combined issue of classimbalance and concept drift are lacking in understating of correlation of oneproblem with the other. This work studies the association between conceptdrift and class imbalance ratio and then demonstrates how changes in classimbalance ratio along with concept drift affect the classifier’s performance.We analyzed the effect of both the issues on minority and majority classesindividually. To do this, we conducted experiments on benchmark datasetsusing state-of-the-art classifiers especially designed for data stream classification.Precision, recall, F1 score, and geometric mean were used to measure theperformance. Our findings show that when both class imbalance and conceptdrift problems occur together the performance can decrease up to 15%. Ourresults also show that the increase in the imbalance ratio can cause a 10% to15% decrease in the precision scores of both minority and majority classes.The study findings may help in designing intelligent and adaptive solutionsthat can cope with the challenges of non-stationary data streams like conceptdrift and class imbalance.展开更多
Since its inception in the 1970s,multi-dimensional magnetic resonance(MR)has emerged as a powerful tool for non-invasive investigations of structures and molecular interactions.MR spectroscopy beyond one dimension all...Since its inception in the 1970s,multi-dimensional magnetic resonance(MR)has emerged as a powerful tool for non-invasive investigations of structures and molecular interactions.MR spectroscopy beyond one dimension allows the study of the correlation,exchange processes,and separation of overlapping spectral information.The multi-dimensional concept has been re-implemented over the last two decades to explore molecular motion and spin dynamics in porous media.Apart from Fourier transform,methods have been developed for processing the multi-dimensional time-domain data,identifying the fluid components,and estimating pore surface permeability via joint relaxation and diffusion spectra.Through the resolution of spectroscopic signals with spatial encoding gradients,multi-dimensional MR imaging has been widely used to investigate the microscopic environment of living tissues and distinguish diseases.Signals in each voxel are usually expressed as multi-exponential decay,representing microstructures or environments along multiple pore scales.The separation of contributions from different environments is a common ill-posed problem,which can be resolved numerically.Moreover,the inversion methods and experimental parameters determine the resolution of multi-dimensional spectra.This paper reviews the algorithms that have been proposed to process multidimensional MR datasets in different scenarios.Detailed information at the microscopic level,such as tissue components,fluid types and food structures in multi-disciplinary sciences,could be revealed through multi-dimensional MR.展开更多
Indium oxide(In_(2)O_(3)),as a promising candidate for CO_(2)hydrogenation to C_(1) products,often suffers from sintering and activity decline,closely related to the undesirable structural evolution under reaction con...Indium oxide(In_(2)O_(3)),as a promising candidate for CO_(2)hydrogenation to C_(1) products,often suffers from sintering and activity decline,closely related to the undesirable structural evolution under reaction conditions.Based on the comprehension of the dynamic evolution,this study presents an efficient strategy to alleviate the agglomeration of In_(2)O_(3)nanoparticles by the surface decoration with highly dispersed silica species(SiO_(x)).Various structural characterizations combined with density functional theory calculations demonstrated that the sintering resulted from the over-reduction,while the enhanced stability originated from the anchoring effect of highly stable In-OSi bonds,which hinders the substantial formation of metallic In(In^(0))and the subsequent agglomeration.0.6Si/In_(2)O_(3)exhibited CO_(2)conversion rate of10.0 mmol g^(-1)h^(-1)at steady state vs.3.5 mmol g^(-1)h^(-1)on In_(2)O_(3)in CO_(2)hydrogenation.Enhanced steady-state activity was also achieved on Pd-modified catalysts.Compared to the traditional Pd/In_(2)O_(3)catalyst,the methanol production rate of Pd catalyst supported on 0.6Si/In_(2)O_(3)was enhanced by 23%,showing the potential of In_(2)O_(3)modified by SiO_(x)in serving as a platform material.This work provides a promising method to design new In_(2)O_(3)-based catalysts with improved activity and stability in CO_(2)hydrogenation.展开更多
Detection and mitigation of radio frequency interference (RFI) is the first and also the key step for data processing in radio observations, especially for ongoing low frequency radio experiments towards the detecti...Detection and mitigation of radio frequency interference (RFI) is the first and also the key step for data processing in radio observations, especially for ongoing low frequency radio experiments towards the detection of the cosmic dawn and epoch of reionization (EoR). In this paper we demonstrate the tech- nique and efficiency of RFI identification and mitigation for the 21 Centimeter Array (21CMA), a radio interferometer dedicated to the statistical measurement of EoR. For terrestrial, man-made RFI, we concen- trate mainly on a statistical approach by identifying and then excising non-Gaussian signatures, in the sense that the extremely weak cosmic signal is actually buried under thermal and therefore Gaussian noise. We also introduce the so-called visibility correlation coefficient instead of conventional visibility, which allows a further suppression of rapidly time-varying RFI. Finally, we briefly discuss removals of the sky RFI, the leakage of sidelobes from off-field strong radio sources with time-invariant power and a featureless spec- trum. It turns out that state of the art technique should allow us to detect and mitigate RFI to a satisfactory level in present low frequency interferometer observations such as those acquired with the 21CMA, and the accuracy and efficiency can be greatly improved with the employment of low-cost, high-speed computing facilities for data acquisition and processing.展开更多
The accessory reproductive glands of male mammals contribute the bulk of the secretions in which spermatozoa are transported to the female tract during copulation. Despite their morphological diversity,and the chemica...The accessory reproductive glands of male mammals contribute the bulk of the secretions in which spermatozoa are transported to the female tract during copulation. Despite their morphological diversity,and the chemical complexity of their products,little is known about the possible effects of sexual selection upon these glands in mammals. Here we consider the seminal vesicles and prostate glands in a sample of 89 species and 60 genera representing 8 Orders of mammals. The sizes of the accessory glands are analysed in relation to body weight and testes weight. Both the seminal vesicles size and prostate size (corrected for body weight) correlate positively with relative testes size in this sample; this finding remains highly significant after application of procedures to correct for possible phylogenetic biases in the data set. The accessory reproductive glands are also significantly larger in those mammals which have large relative testes sizes,and in which the likelihood of sperm competition is greatest. These results support the hypothesis that sexual selection has played an important role in the evolution of the mammalian prostate gland and seminal展开更多
Based on the stochastic AMR model, this paper constructs man-made earthquake catalogues to investigate the property of parameter estimation of the model. Then the stochastic AMR model is applied to the study of severa...Based on the stochastic AMR model, this paper constructs man-made earthquake catalogues to investigate the property of parameter estimation of the model. Then the stochastic AMR model is applied to the study of several strong earthquakes in China and New Zealand. Akaikes AIC criterion is used to discriminate whether an accelerating mode of earthquake activity precedes those events or not. Finally, regional accelerating seismic activity and possible prediction approach for future strong earthquakes are discussed.展开更多
The present study proposes an index to assess the potential for adaptation to climate change for households in the mountainous regions. The index provides a realistic approach to recognize social and natural factors w...The present study proposes an index to assess the potential for adaptation to climate change for households in the mountainous regions. The index provides a realistic approach to recognize social and natural factors which contribute to successful adaptation and addresses several household functions,such as social networking, livelihood strategy, adjustment strategies, resource availability and accessibility. The proposed Adaptation Capability Index(ACI) is analytically defined, mathematically formulated and field tested on mountainous households in urban and semi-urban regions of the Uttarakhand Himalaya in India. To gather data on the topic relevant to the ACI, a household scale questionnaire was developed and administered to 120 heads of households through face-to-face interviews. The results highlight higher adaptive capability of urban households and low adaptation capacity of rural households due to poor farm productivity, low accessibility and availability of resources and technological input. Future programs and policies must include and implement regulations to remedy attributive factors responsible for higher adaptation. This paper may be applicable to other mountainous regions and may provide insights for effective adaptation strategies to climate change.展开更多
Arsenic is a carcinogen known for its acute toxicity to organisms.Geothermal waters are commonly high in arsenic,as shown at the Bjarnarflag Power Plant,Iceland (w224 mg/kg of solvent).Development of geothermal energy...Arsenic is a carcinogen known for its acute toxicity to organisms.Geothermal waters are commonly high in arsenic,as shown at the Bjarnarflag Power Plant,Iceland (w224 mg/kg of solvent).Development of geothermal energy requires adequate disposal of arsenic-rich waters into groundwater/geothermal systems.The outcome of arsenic transport models that assess the effect of geothermal effluent on the environment and ecosystems may be influenced by the sensitivity of hydraulic parameters.However,previous such studies in Iceland do not consider the sensitivity of hydraulic parameters and thereby the interpretations remain unreliable.Here we used the Lake Myvatn basaltic aquifer system as a case study to identify the sensitive hydraulic parameters and assess their role in arsenic transport.We develop a one-dimensional reactive transport model (PHREEQC ver.2.),using geochemical data from Bjarnarflag,Iceland.In our model,arsenite (H3AsO3) was predicted to be the dominant species of inorganic arsenic in both groundwater and geothermal water.Dilution reduced arsenic concentration beloww5 mg/kg.Adsorption reduced the residual contamination below w0.4 mg/kg at 250 m along transect.Based on our modelling,we found volumetric input to be the most sensitive parameter in the model.In addition,the adsorption strength of basaltic glass was such that the physical hydrogeological parameters,namely: groundwater velocity and longitudinal dispersivity had little influence on the concentration profile.展开更多
The absence of ultrahigh pressure(UHP)orogenic eclogite in the geological record older than c.0.6 Ga is problematic for evidence of subduction having begun on Earth during the Archean(4.0-2.5 Ga).Many eclogites in Pha...The absence of ultrahigh pressure(UHP)orogenic eclogite in the geological record older than c.0.6 Ga is problematic for evidence of subduction having begun on Earth during the Archean(4.0-2.5 Ga).Many eclogites in Phanerozoic and Proterozoic terranes occur as mafic boudins encased within low-density felsic crust,which provides positive buoyancy during subduction;however,recent geochemical proxy analysis shows that Archean continental crust was more mafic than previously thought,having greater proportions of basalt and komatiite than modern-day continents.Here,we show via petrological modelling that secular change in the petrology and bulk composition of upper continental crust would make Archean continental terranes negatively buoyant in the mantle before reaching UHP conditions.Subducted or delaminated Archean continental crust passes a point of no return during metamorphism in the mantle prior to the stabilization of coesite,while Proterozoic and Phanerozoic terranes remain positively buoyant at these depths.UHP orogenic eclogite may thus readily have formed on the Archean Earth,but could not have been exhumed,weakening arguments for a Neoproterozoic onset of subduction and plate tectonics.Further,isostatic balance calculations for more mafic Archean continents indicate that the early Earth was covered by a global ocean over 1 km deep,corroborating independent isotopic evidence for large-scale emergence of the continents no earlier than c.3 Ga.Our findings thus weaken arguments that early life on Earth likely emerged in shallow subaerial ponds,and instead support hypotheses involving development at hydrothermal vents in the deep ocean.展开更多
We present combined photometric and spectroscopic analyses of the southern binary star PU Pup.High-resolution spectra of this system were taken at the University of Canterbury Mt.John Observatory in the years 2008 and...We present combined photometric and spectroscopic analyses of the southern binary star PU Pup.High-resolution spectra of this system were taken at the University of Canterbury Mt.John Observatory in the years 2008 and again in 2014-2015.We find the light contribution of the secondary component to be only 2%of the total light of the system in optical wavelengths,resulting in a single-lined spectroscopic binary.Recent TESS data revealed grazing eclipses within the light minima,though the tidal distortion,examined also from Hipparcos data,remains the predominating light curve effect.Our model shows PU Pup to have the more massive primary relatively close to filling its Roche lobe.PU Pup is thus approaching the rare‘fast phase’of interactive(Case B)evolution.Our adopted absolute parameters are as follows:M_(1)=4.10(±0.20)M_(⊙),M_(2)=0.65(±0.05)M_(⊙),R_(1)=6.60(±0.30)R_(⊙),R_(2)=0.90(±0.10)R_(⊙);T_(1)=11500(±500)K,T_(2)=5000(±350)K;photometric distance=186(±20)pc,age=170(±20)Myr.The less-massive secondary component is found to be significantly oversized and overluminous compared to standard main sequence models.We discuss this discrepancy referring to heating from the reflection effect.展开更多
The growth of the ageing population and the desires for ageing-in-place have resulted in an ever-increasing need for housing that can support the independent living of the elderly with care needs.As impairments and ca...The growth of the ageing population and the desires for ageing-in-place have resulted in an ever-increasing need for housing that can support the independent living of the elderly with care needs.As impairments and care needs increase,spatial use typically changes.However,there is limited information on how to accommodate leisure activities and spatial use in private dwellings to inform housing design.Through an ethnographic investigation of 30 high-needs elderly people living independently,patterns of spatial use for personal leisure activities were established.Seven key themes for residents’perceptions were revealed,which include;comfort in posture,access to sunshine and warmth,facilitating activities to occupy residents,views to outside,control for doing everything from one space,and keeping active.In the design of housing for the high-needs elderly,greater attention should be given to the micro-environment of the main sitting space,to improve occupant control while enhancing comfort and warmth.This paper provides key considerations for housing design,which will help elderly people continue their fulfilled life in their own home as long as possible.展开更多
This paper examines the filming practice of Zhang Yimou’s Shadow(2018)in the context of Chinese culture and from the perspectives of contemporary gender theories.It argues that Shadow constructs a male-dominated patr...This paper examines the filming practice of Zhang Yimou’s Shadow(2018)in the context of Chinese culture and from the perspectives of contemporary gender theories.It argues that Shadow constructs a male-dominated patriarchal culture and a patricide allegory of the Father and Son structure of power in palace intrigues.Furthermore,it is a history of the acts that the Son takes to get the Father’s woman,absolve the tyrannical Father’s threat of castration and attain the supreme power.To suit the motif of palace intrigues,Zhang adopts quasi-back-and-white palette to create stunning visuals like traditional Chinese ink paintings.He also constructs a web-narrative of dualities around the yin-yang paradigm,the taichi diagram in particular.The film’s central gender relationship is a triangular one,in which Woman is positioned between the Father/the master and the Son/his“shadow”.Woman is marginalized in the film.She is not represented as the central subject,but as the object of sacrifice who functions to satisfy male desire and construct male subjectivity and sexuality.Moreover,the film explores how toxic and violent Chinese masculinity can become when it deviates from wen-wu prowess.Thus,Shadow becomes a violent movie that intensifies the viewer’s experience of violence as the Son/the“shadow”must be absolutely brutal and ruthless in order to slay the Father/the master and create new order.展开更多
Background Accurate motion tracking in head-mounted displays(HMDs)has been widely used in immersive VR interaction technologies.However,tracking the head motion of users at all times is not always desirable.During a s...Background Accurate motion tracking in head-mounted displays(HMDs)has been widely used in immersive VR interaction technologies.However,tracking the head motion of users at all times is not always desirable.During a session of HMD usage,users may make scene-irrelevant head rotations,such as adjusting the head position to avoid neck pain or responding to distractions from the physical world.To the best of our knowledge,this is the first study that addresses the problem of scene-irrelevant head movements.Methods We trained a classifier to detect scene-irrelevant motions using temporal eye head-coordinated information sequences.To investigate the usefulness of the detection results,we propose a technique to suspend motion tracking in HMDs where scene-irrelevant motions are detected.Results/Conclusions Experimental results demonstrate that the scene-relevancy of movements can be detected using eye-head coordination information,and that ignoring scene-irrelevant head motions in HMDs improves user continuity without increasing sickness or breaking immersion.展开更多
基金The authors would like to extend their gratitude to Universiti Teknologi PETRONAS (Malaysia)for funding this research through grant number (015LA0-037).
文摘Every application in a smart city environment like the smart grid,health monitoring, security, and surveillance generates non-stationary datastreams. Due to such nature, the statistical properties of data changes overtime, leading to class imbalance and concept drift issues. Both these issuescause model performance degradation. Most of the current work has beenfocused on developing an ensemble strategy by training a new classifier on thelatest data to resolve the issue. These techniques suffer while training the newclassifier if the data is imbalanced. Also, the class imbalance ratio may changegreatly from one input stream to another, making the problem more complex.The existing solutions proposed for addressing the combined issue of classimbalance and concept drift are lacking in understating of correlation of oneproblem with the other. This work studies the association between conceptdrift and class imbalance ratio and then demonstrates how changes in classimbalance ratio along with concept drift affect the classifier’s performance.We analyzed the effect of both the issues on minority and majority classesindividually. To do this, we conducted experiments on benchmark datasetsusing state-of-the-art classifiers especially designed for data stream classification.Precision, recall, F1 score, and geometric mean were used to measure theperformance. Our findings show that when both class imbalance and conceptdrift problems occur together the performance can decrease up to 15%. Ourresults also show that the increase in the imbalance ratio can cause a 10% to15% decrease in the precision scores of both minority and majority classes.The study findings may help in designing intelligent and adaptive solutionsthat can cope with the challenges of non-stationary data streams like conceptdrift and class imbalance.
基金supported by the National Natural Science Foundation of China(No.61901465,82222032,82172050).
文摘Since its inception in the 1970s,multi-dimensional magnetic resonance(MR)has emerged as a powerful tool for non-invasive investigations of structures and molecular interactions.MR spectroscopy beyond one dimension allows the study of the correlation,exchange processes,and separation of overlapping spectral information.The multi-dimensional concept has been re-implemented over the last two decades to explore molecular motion and spin dynamics in porous media.Apart from Fourier transform,methods have been developed for processing the multi-dimensional time-domain data,identifying the fluid components,and estimating pore surface permeability via joint relaxation and diffusion spectra.Through the resolution of spectroscopic signals with spatial encoding gradients,multi-dimensional MR imaging has been widely used to investigate the microscopic environment of living tissues and distinguish diseases.Signals in each voxel are usually expressed as multi-exponential decay,representing microstructures or environments along multiple pore scales.The separation of contributions from different environments is a common ill-posed problem,which can be resolved numerically.Moreover,the inversion methods and experimental parameters determine the resolution of multi-dimensional spectra.This paper reviews the algorithms that have been proposed to process multidimensional MR datasets in different scenarios.Detailed information at the microscopic level,such as tissue components,fluid types and food structures in multi-disciplinary sciences,could be revealed through multi-dimensional MR.
基金financially supported by the National Natural Science Foundation of China(22172013)the Special Project for Key Research and Development Program of Xinjiang Autonomous Region(2022B01033-3)+3 种基金the Liaoning Revitalization Talent Program(XLYC2008032 and XLYC2203126)the Fundamental Research Funds for the Central Universities(DUT22LK24,DUT22QN207 and DUT22LAB602)the CUHK Research Startup Fund(No.#4930981)financial support from Catalyst:Seeding funding(CSG-VUW2201)provided by the New Zealand Ministry of Business,Innovation and Employment and administered by the Royal Society Aparangi。
文摘Indium oxide(In_(2)O_(3)),as a promising candidate for CO_(2)hydrogenation to C_(1) products,often suffers from sintering and activity decline,closely related to the undesirable structural evolution under reaction conditions.Based on the comprehension of the dynamic evolution,this study presents an efficient strategy to alleviate the agglomeration of In_(2)O_(3)nanoparticles by the surface decoration with highly dispersed silica species(SiO_(x)).Various structural characterizations combined with density functional theory calculations demonstrated that the sintering resulted from the over-reduction,while the enhanced stability originated from the anchoring effect of highly stable In-OSi bonds,which hinders the substantial formation of metallic In(In^(0))and the subsequent agglomeration.0.6Si/In_(2)O_(3)exhibited CO_(2)conversion rate of10.0 mmol g^(-1)h^(-1)at steady state vs.3.5 mmol g^(-1)h^(-1)on In_(2)O_(3)in CO_(2)hydrogenation.Enhanced steady-state activity was also achieved on Pd-modified catalysts.Compared to the traditional Pd/In_(2)O_(3)catalyst,the methanol production rate of Pd catalyst supported on 0.6Si/In_(2)O_(3)was enhanced by 23%,showing the potential of In_(2)O_(3)modified by SiO_(x)in serving as a platform material.This work provides a promising method to design new In_(2)O_(3)-based catalysts with improved activity and stability in CO_(2)hydrogenation.
基金partially supported by the National Natural Science Foundation of China(Grant No.11433002)support by a Marsden Fund grant in New Zealand
文摘Detection and mitigation of radio frequency interference (RFI) is the first and also the key step for data processing in radio observations, especially for ongoing low frequency radio experiments towards the detection of the cosmic dawn and epoch of reionization (EoR). In this paper we demonstrate the tech- nique and efficiency of RFI identification and mitigation for the 21 Centimeter Array (21CMA), a radio interferometer dedicated to the statistical measurement of EoR. For terrestrial, man-made RFI, we concen- trate mainly on a statistical approach by identifying and then excising non-Gaussian signatures, in the sense that the extremely weak cosmic signal is actually buried under thermal and therefore Gaussian noise. We also introduce the so-called visibility correlation coefficient instead of conventional visibility, which allows a further suppression of rapidly time-varying RFI. Finally, we briefly discuss removals of the sky RFI, the leakage of sidelobes from off-field strong radio sources with time-invariant power and a featureless spec- trum. It turns out that state of the art technique should allow us to detect and mitigate RFI to a satisfactory level in present low frequency interferometer observations such as those acquired with the 21CMA, and the accuracy and efficiency can be greatly improved with the employment of low-cost, high-speed computing facilities for data acquisition and processing.
文摘The accessory reproductive glands of male mammals contribute the bulk of the secretions in which spermatozoa are transported to the female tract during copulation. Despite their morphological diversity,and the chemical complexity of their products,little is known about the possible effects of sexual selection upon these glands in mammals. Here we consider the seminal vesicles and prostate glands in a sample of 89 species and 60 genera representing 8 Orders of mammals. The sizes of the accessory glands are analysed in relation to body weight and testes weight. Both the seminal vesicles size and prostate size (corrected for body weight) correlate positively with relative testes size in this sample; this finding remains highly significant after application of procedures to correct for possible phylogenetic biases in the data set. The accessory reproductive glands are also significantly larger in those mammals which have large relative testes sizes,and in which the likelihood of sperm competition is greatest. These results support the hypothesis that sexual selection has played an important role in the evolution of the mammalian prostate gland and seminal
基金National Natural Science Foundation of China (40074013, 40134010), Chinese Joint Seismological Science Foundation (042002) and the project during the Tenth Five-year Plan.
文摘Based on the stochastic AMR model, this paper constructs man-made earthquake catalogues to investigate the property of parameter estimation of the model. Then the stochastic AMR model is applied to the study of several strong earthquakes in China and New Zealand. Akaikes AIC criterion is used to discriminate whether an accelerating mode of earthquake activity precedes those events or not. Finally, regional accelerating seismic activity and possible prediction approach for future strong earthquakes are discussed.
文摘The present study proposes an index to assess the potential for adaptation to climate change for households in the mountainous regions. The index provides a realistic approach to recognize social and natural factors which contribute to successful adaptation and addresses several household functions,such as social networking, livelihood strategy, adjustment strategies, resource availability and accessibility. The proposed Adaptation Capability Index(ACI) is analytically defined, mathematically formulated and field tested on mountainous households in urban and semi-urban regions of the Uttarakhand Himalaya in India. To gather data on the topic relevant to the ACI, a household scale questionnaire was developed and administered to 120 heads of households through face-to-face interviews. The results highlight higher adaptive capability of urban households and low adaptation capacity of rural households due to poor farm productivity, low accessibility and availability of resources and technological input. Future programs and policies must include and implement regulations to remedy attributive factors responsible for higher adaptation. This paper may be applicable to other mountainous regions and may provide insights for effective adaptation strategies to climate change.
基金Landsvirkjun and the Landsvirkjun Energy Research Fund for supporting this project
文摘Arsenic is a carcinogen known for its acute toxicity to organisms.Geothermal waters are commonly high in arsenic,as shown at the Bjarnarflag Power Plant,Iceland (w224 mg/kg of solvent).Development of geothermal energy requires adequate disposal of arsenic-rich waters into groundwater/geothermal systems.The outcome of arsenic transport models that assess the effect of geothermal effluent on the environment and ecosystems may be influenced by the sensitivity of hydraulic parameters.However,previous such studies in Iceland do not consider the sensitivity of hydraulic parameters and thereby the interpretations remain unreliable.Here we used the Lake Myvatn basaltic aquifer system as a case study to identify the sensitive hydraulic parameters and assess their role in arsenic transport.We develop a one-dimensional reactive transport model (PHREEQC ver.2.),using geochemical data from Bjarnarflag,Iceland.In our model,arsenite (H3AsO3) was predicted to be the dominant species of inorganic arsenic in both groundwater and geothermal water.Dilution reduced arsenic concentration beloww5 mg/kg.Adsorption reduced the residual contamination below w0.4 mg/kg at 250 m along transect.Based on our modelling,we found volumetric input to be the most sensitive parameter in the model.In addition,the adsorption strength of basaltic glass was such that the physical hydrogeological parameters,namely: groundwater velocity and longitudinal dispersivity had little influence on the concentration profile.
文摘The absence of ultrahigh pressure(UHP)orogenic eclogite in the geological record older than c.0.6 Ga is problematic for evidence of subduction having begun on Earth during the Archean(4.0-2.5 Ga).Many eclogites in Phanerozoic and Proterozoic terranes occur as mafic boudins encased within low-density felsic crust,which provides positive buoyancy during subduction;however,recent geochemical proxy analysis shows that Archean continental crust was more mafic than previously thought,having greater proportions of basalt and komatiite than modern-day continents.Here,we show via petrological modelling that secular change in the petrology and bulk composition of upper continental crust would make Archean continental terranes negatively buoyant in the mantle before reaching UHP conditions.Subducted or delaminated Archean continental crust passes a point of no return during metamorphism in the mantle prior to the stabilization of coesite,while Proterozoic and Phanerozoic terranes remain positively buoyant at these depths.UHP orogenic eclogite may thus readily have formed on the Archean Earth,but could not have been exhumed,weakening arguments for a Neoproterozoic onset of subduction and plate tectonics.Further,isostatic balance calculations for more mafic Archean continents indicate that the early Earth was covered by a global ocean over 1 km deep,corroborating independent isotopic evidence for large-scale emergence of the continents no earlier than c.3 Ga.Our findings thus weaken arguments that early life on Earth likely emerged in shallow subaerial ponds,and instead support hypotheses involving development at hydrothermal vents in the deep ocean.
文摘We present combined photometric and spectroscopic analyses of the southern binary star PU Pup.High-resolution spectra of this system were taken at the University of Canterbury Mt.John Observatory in the years 2008 and again in 2014-2015.We find the light contribution of the secondary component to be only 2%of the total light of the system in optical wavelengths,resulting in a single-lined spectroscopic binary.Recent TESS data revealed grazing eclipses within the light minima,though the tidal distortion,examined also from Hipparcos data,remains the predominating light curve effect.Our model shows PU Pup to have the more massive primary relatively close to filling its Roche lobe.PU Pup is thus approaching the rare‘fast phase’of interactive(Case B)evolution.Our adopted absolute parameters are as follows:M_(1)=4.10(±0.20)M_(⊙),M_(2)=0.65(±0.05)M_(⊙),R_(1)=6.60(±0.30)R_(⊙),R_(2)=0.90(±0.10)R_(⊙);T_(1)=11500(±500)K,T_(2)=5000(±350)K;photometric distance=186(±20)pc,age=170(±20)Myr.The less-massive secondary component is found to be significantly oversized and overluminous compared to standard main sequence models.We discuss this discrepancy referring to heating from the reflection effect.
文摘The growth of the ageing population and the desires for ageing-in-place have resulted in an ever-increasing need for housing that can support the independent living of the elderly with care needs.As impairments and care needs increase,spatial use typically changes.However,there is limited information on how to accommodate leisure activities and spatial use in private dwellings to inform housing design.Through an ethnographic investigation of 30 high-needs elderly people living independently,patterns of spatial use for personal leisure activities were established.Seven key themes for residents’perceptions were revealed,which include;comfort in posture,access to sunshine and warmth,facilitating activities to occupy residents,views to outside,control for doing everything from one space,and keeping active.In the design of housing for the high-needs elderly,greater attention should be given to the micro-environment of the main sitting space,to improve occupant control while enhancing comfort and warmth.This paper provides key considerations for housing design,which will help elderly people continue their fulfilled life in their own home as long as possible.
文摘This paper examines the filming practice of Zhang Yimou’s Shadow(2018)in the context of Chinese culture and from the perspectives of contemporary gender theories.It argues that Shadow constructs a male-dominated patriarchal culture and a patricide allegory of the Father and Son structure of power in palace intrigues.Furthermore,it is a history of the acts that the Son takes to get the Father’s woman,absolve the tyrannical Father’s threat of castration and attain the supreme power.To suit the motif of palace intrigues,Zhang adopts quasi-back-and-white palette to create stunning visuals like traditional Chinese ink paintings.He also constructs a web-narrative of dualities around the yin-yang paradigm,the taichi diagram in particular.The film’s central gender relationship is a triangular one,in which Woman is positioned between the Father/the master and the Son/his“shadow”.Woman is marginalized in the film.She is not represented as the central subject,but as the object of sacrifice who functions to satisfy male desire and construct male subjectivity and sexuality.Moreover,the film explores how toxic and violent Chinese masculinity can become when it deviates from wen-wu prowess.Thus,Shadow becomes a violent movie that intensifies the viewer’s experience of violence as the Son/the“shadow”must be absolutely brutal and ruthless in order to slay the Father/the master and create new order.
文摘Background Accurate motion tracking in head-mounted displays(HMDs)has been widely used in immersive VR interaction technologies.However,tracking the head motion of users at all times is not always desirable.During a session of HMD usage,users may make scene-irrelevant head rotations,such as adjusting the head position to avoid neck pain or responding to distractions from the physical world.To the best of our knowledge,this is the first study that addresses the problem of scene-irrelevant head movements.Methods We trained a classifier to detect scene-irrelevant motions using temporal eye head-coordinated information sequences.To investigate the usefulness of the detection results,we propose a technique to suspend motion tracking in HMDs where scene-irrelevant motions are detected.Results/Conclusions Experimental results demonstrate that the scene-relevancy of movements can be detected using eye-head coordination information,and that ignoring scene-irrelevant head motions in HMDs improves user continuity without increasing sickness or breaking immersion.