145 research outputs found
Impacts of industrial heterogeneity and technical innovation on the relationship between environmental performance and financial performance
In this paper, we investigate the relationship between environmental performance (EP) and financial performance (FP) from the perspective of technical innovation in Chinese industrial sectors. We also consider industrial heterogeneity and take temporal variations of the link into account. We collect the required data from different Chinese statistical yearbooks from 2004 to 2015. We use an aggregated index of environmental pollutants as a proxy for EP and return on assets as a proxy for FP, and we employ research and development expenditure to capture technical innovation. The empirical results indicate that industrial heterogeneity exists and the EPâFP link varies in different industrial groups. There is no evidence that the EPâFP link becomes more positive and more significant over time. Furthermore, the mediation effect of technical innovation and environmental pressures can jointly affect the link. Finally, technical innovation partially mediates the EPâFP link but only in Chinese light-polluting sectors not in heavy-polluting sectors. The mediating role of technical innovation has a great impact on shaping the EPâFP link. When technical innovation partially mediates the focal link, apart from the indirect link, the direct EPâFP link is likely to be positive. If not, the direct EPâFP link is likely to be negative
Diffusion-Mediated Deposition of Proteins
Gradients of proteins play a prominent role in many biological processes, from development of multicellular organisms to chemical signaling in the immune system. Deposition of surface gradients is a way to permanently modifying a surfaceâs properties, resulting in the creation of novel materials which have widespread applications in biologically relevant fields, such as directed cell growth, production of biocompatible implantable materials, and creation of functional biosensors. These types of surfaces can also be used as an ex vivo tool to help understand many biological processes by mimicking the environment in gradient-related phenomena in a controllable way. However, despite the large number of applications for chemically graded surfaces, creating them remains a challenge.
In this work, a novel diffusion-based patterning mechanism is presented that relies on a 3D micropatterned poly(ethylene glycol) diacrylate (PEG-DA) âstampsâ for the controlled deposition of fluorescently-tagged protein âinkâ onto pre-treated glass slides. By controlling the contact time and mechanical deformation of the PEG hydrogel on the glass surfaces, it is possible to control local concentration of protein deposition
Dominant controls on organic-rich shale deposition: Geochemical evidences from the Marcellus Shale in the Appalachian basin
This dissertation presents new results of the linkages between primary productivity, bottom water redox conditions and clastic input associated with the Acadian orogeny of the Marcellus Shale.;Chapter 1 compares the isotopic and geochemical characteristics of sediments of a liquids-prone well (WV-7) in Wetzel County with a gas-prone well (WV-6) in Monongalia County, northern West Virginia. The difference in organic carbon isotopes indicates that the dominant organic matter preserved in each core is different: delta13Corg values are lighter on average in WV-6 compared with WV-7. A possible explanation is that a larger fraction of terrestrial organic matter was preserved in the WV-6 core, whereas WV-7 may contain a greater percentage of marine organic matter. Clastic-influx proxies (e.g. Ti/Al, Ca/Al and Mg/Al) also suggest that the WV-6 core site received a higher sediment input compared to WV-7, consistent with a more proximal location to dry land and the delivery of greater amounts of terrestrial organic matter. Depleted delta13C carb values, low concentrations of redox sensitive elements (e.g. V, Cr, Ni and U), and high variability delta15N values in the WV-6 core all suggest the presence of higher dissolved oxygen concentration and short term shifts in an oxic/anoxic boundary near the sediment-water interface during deposition. This indicates that the depositional conditions were favorable for the accumulation of predominantly gas-prone Type III kerogen in the Marcellus Shale at the WV-6 site. In contrast, the Marcellus Shale at the WV-7 site was deposited in a more distal area that received a low terrestrial sediment supply, organic matter primarily derived from marine algae, and bottom water conditions that were dominantly anoxic. Such conditions were favorable for the accumulation of Type II kerogen that has a greater capacity to generate liquid hydrocarbons.;Chapter 2 employs geochemical, isotopic in combination with petrographic analyses from a core of the Marcellus Shale obtained from Greene County, Pennsylvania, to understand the dominant controls on organic matter deposition in the black shale study units. This study suggests that the regeneration of nutrients, such as nitrogen (N) and phosphorous (P), may have played a key role in the formation of organic carbon (OC)-rich intervals in the Marcellus Shale. The ratios of Corg/Nbulk and Corg/P tot are significantly higher in the OC-rich zone of the core (i.e., defined as TOC \u3e 4% and located between 2393 and 2406.5 m depth). The high Corg/Ptot and Corg/Nbulk ratios of the preserved organic matter may reflect the release of N and P by microbial processes, indicating the recycling of nutrients during deposition of the OC-rich interval. In addition, our data show a positive relationships between the Corg/Ptot and Corg/Nbulk ratios and the organic carbon content, which indicate that the recycled nutrients may have promoted primary productivity, resulting in higher OC accumulation in some intervals. The geochemical and stable isotopic results also suggest that the alternating redox conditions in the water mass were favorable for nutrient regeneration. Highly variable trace metal concentrations (e.g., U, Mo, V) in the OC-rich zone and a wide range of delta15N and delta 34Spyr values towards the top of the OC-rich zone suggest fluctuations between anoxic and suboxic water conditions. Finally, sedimentary features and agglutinated benthic foraminifera in the OC-rich zone support the existence of short-term fluctuations between suboxic and anoxic conditions near the sediment-water interface.;Chapter 3 reports trace and rare earth elements (REE) of the samples collected from a 30-m core of the Marcellus Shale obtained from Greene County, southwestern Pennsylvania. This study provides the direct links between organic matter enrichment trends in the Marcellus Shale with the Acadian orogeny. The Acadian orogen has been recognized as a main sediment source for the Marcellus Shale. Synthesis of tectonic history and recent ash bed geochronology, reveals that deposition of the organic carbon-rich (OR) zone (characterized by TOC \u3e4%; located between 2393 m and 2406.5 m core depth) in the studied Marcellus Shale core was coincident with tectonically active and magmatic quiescent period of the Acadian orogeny (ca. 395--380 Ma). This time also corresponds to the period when mountain building in the Acadian orogen was at its highest rates. The light rare earth (LREE) and selected trace elemental (e.g., Ta, Cs) composition of the OR zone sediments is similar to that of the bulk continental crust, supporting the lack of magmatic activity in the source area (i.e. Acadian orogen). In contrast, subsequent deposition of the organic carbon-poor (OP) sediments (characterized by TOC \u3c4%; located between 2376 m and 2393 m core depth) in the upper Marcellus Shale occurred synchronously with a magmatic active phase (ca. 380--370 Ma) during the Acadian orogeny. The OP zone sediments have LREE and trace elements composition similar to that of the upper continental crust. (Abstract shortened by UMI.)
Exploring the relationships between different types of environmental regulations and environmental performance : evidence from China
The literature on the relationship between environmental regulations (ERs) and environmental performance (EP) of firms has largely ignored consideration of different kinds of ERs and the potential non-linear relationship between ERs and EP. This study uses the literature to differentiate three types of ERs (command-and-control regulations, market-based regulations and informal regulations) and further investigates (i) the linear links between different types of ERs and EP, and (ii) the potential non-linear relationships. The results provide support that the links between ERs and EP are not linear for command-and-control regulations and market-based regulations but non-linear and positive. For informal regulations, both the linear and non-linear relationships are not significant. We further test the impacts of time lag effects. Command-and-control regulations have impacts on EP both in current and the preceding years, whereas market-based regulations only affect EP in current year rather than in the preceding years. It takes 2 years to see the effects of informal regulations on EP
Muddled Loyalty: A Study of Islamic Centers in Boston Area
Thesis advisor: Peter SkerryThis thesis is a further study of Peter Skerryâs 2011 article, âthe Muslim-American Muddle,â in which he argues that not only non-Muslim Americans are worrying about Muslimsâ loyalty issue due to the fear of radical Islamism and terrorism, but also Muslims are confused. My basic argument is that Muslims are still suffering from their muddled loyalty. It is not because they are disloyal but because, in light of Grodzins, their organizations guide them in different directions which are not always en route to national loyalty as non-Muslims expect. Inspired by Morton Grodzinsâs theory on social structure and national loyalty in liberal democracies and James Q. Wilsonâs insightful study on political organizations, this research has sought to understand the Muslim muddle with an in-depth inquiry and examination on one of the most common and important Islamic organizationsâIslamic centers and mosques with an ethnographical method. The evidence of this thesis was collected between April 2016 and December 2017. In fact, I almost visited every mosque in Massachusetts. However, I was not always lucky to build strong connections with many centers for various reasons. In this thesis, I only select those mosques that I had visited more than three times. And I try my best to interview as many leaders as possible. I also manage to keep a geographical and sectarian balance in my sample. I hope to cover all types of mosques in Boston area. My findings are interesting, though of course often confusing and may contradicting with each other but I am duty-bound to report them even if it may had negative impact on the generalization power of my argument. I find that Islamic centers have different goals and offer different incentives to overcome collective actions problems. Both solidarity and political engagement are valued by Islamic centers in general, but individual organizations have different preferences which are results of divergent immigrant experiences. So the organizational aspect of Muslims community is fragmented. However, the increasing external political pressure in the post 9/11 period did not overcome the problem but aggravated it by simply empowering purposive mosques like ISBCC in public sphere.Thesis (MA) â Boston College, 2018.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Political Science
Enhancing the machine vision performance with multi-spectral light sources
This study mainly focuses on the performance of different multi-spectral
light sources on different object colors in machine vision and tries to enhance
machine vision with multi-spectral light sources. Using different color pencils
as samples, by recognizing the collected images with two classical neural
networks, AlexNet and VGG19, the performance was investigated under 35
different multi-spectral light sources. The results show that for both models
there are always some non-pure white light sources, whose accuracy is better
than pure white light, which suggests the potential of multi-spectral light
sources to further enhance the effectiveness of machine vision. The comparison
of both models is also performed, and surprised to find that the overall
performance of VGG19 is lower than that of AlexNet, which shows that the
importance of the choice of multi-spectral light sources and models.Comment: 12 pages, 7 figure
Optical ReLU-like Activation Function Based on a Semiconductor Laser with Optical Injection
Artificial neural networks usually consist of successive linear
multiply-accumulate operations and nonlinear activation functions. However,
most optical neural networks only achieve the linear operation in the optical
domain, while the optical implementation of activation function remains
challenging. Here we present an optical ReLU-like activation function based on
a semiconductor laser subject to the optical injection in experiment. The
ReLU-like function is achieved in a broad regime above the Hopf bifurcation of
the injection-locking diagram. In particular, the slope of the activation
function is reconfigurable by tuning the frequency difference between the
master laser and the slave laser
Microstructure and texture evolutions in FeCrAl cladding tube during pilger processing
The microstructure of FeCrAl cladding tubes depends on the fabricating process history. In this study, the microstructural characteristics of wrought FeCrAl alloys during industrial pilger processing into thin-walled tubes were investigated. The hot extruded tube showed âŒ100 ÎŒm equiaxed grains with weak αâ-fiber in {h11}<1/h12> texture, while pilger rolling process change the microstructure to fragmented and elongated grains along the rolling direction. The pilgered textures could be predicted with the VPSC model. The inter-pass annealing at 800â850 \ub0C for 1 h results in recovery and recrystallization of the ferric matrix and restoration of ductility. The final finished tube shows fine recrystallized grains (âŒ11 ÎŒm) with dominant Îł-fiber in three dimensions. Pilger rolling enhanced α-fiber while annealing reduced α-fiber and enhanced Îł-fiber. Microstructural evolution in the Laves precipitates followed the sequence of faceted needle-like â spherical â faceted ellipsoidal. Thermomechanical processing resulted in cladding tubes with an area fraction of âŒ5% and a number density of 5
7 10â11 mâ2 in Laves precipitates, which is half that of the first-pilgered tube. Laves precipitates pin the grain boundaries to control the microstructure and prevent grain coarsening
Diagnosis after Zooming in: A Multi-label Classification Model by Imitating Doctor Reading Habits to Diagnose Brain Diseases
International audiencePurpose: Computed tomography (CT) has the advantages of being low cost and noninvasive and is a primary diagnostic method for brain diseases. However, it is a challenge for junior radiologists to diagnose CT images accurately and comprehensively. It is necessary to build a system that can help doctors diagnose and provide an explanation of the predictions. Despite the success of deep learning algorithms in the field of medical image analysis, the task of brain disease classification still faces challenges: Researchers lack attention to complex manual labeling requirements and the incompleteness of prediction explanations. More importantly, most studies only measure the performance of the algorithm, but do not measure the effectiveness of the algorithm in the actual diagnosis of doctors. Methods: In this paper, we propose a model called DrCT2 that can detect brain diseases without using image-level labels and provide a more comprehensive explanation at both the slice and sequence levels. This model achieves reliable performance by imitating human expert reading habits: targeted scaling of primary images from the full slice scans and observation of suspicious lesions for diagnosis. We evaluated our model on two open-access data sets: CQ500 and the RSNA Intracranial Hemorrhage Detection Challenge. In addition, we defined three tasks to comprehensively evaluate model interpretability by measuring whether the algorithm can select key images with lesions. To verify the algorithm from the perspective of practical application, three junior radiologists were invited to participate in the experiments, comparing the effects before and after human-computer cooperation in different aspects. Results: The method achieved F1-scores of 0.9370 on CQ500 and 0.8700 on the RSNA data set. The results show that our model has good interpretability under the premise of good performance. Human radiologist evaluation experiments have proven that our model can effectively improve the accuracy of the diagnosis and improve efficiency. Conclusions: We proposed a model that can simultaneously detect multiple brain diseases.The report generated by the model can assist doctors in avoiding missed diagnoses, and it has good clinical application value
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