In this paper, a tractable solution is proposed to integrate, to a certain extent, market liquidity risk in the portfolio selection process. It is shown how an investor may take advantage of this additional risk sourc...In this paper, a tractable solution is proposed to integrate, to a certain extent, market liquidity risk in the portfolio selection process. It is shown how an investor may take advantage of this additional risk source within the standard mean-variance optimization framework, by in certain circumstances overcoming the pitfalls of illiquidity and in others seizing a liquidity premium. Bid prices appear effective to capture liquidity risk. The efficient frontier conceived with bid prices consists of mean-variance optimal allocations that cover more liquid stocks （large caps） under stressed market conditions and less liquid stocks （small caps） under normal conditions.展开更多
We present a method to efficiently multiply or divide the orbital angular momentum(OAM)of light beams using a sequence of two optical elements.The key element is represented by an optical transformation mapping the az...We present a method to efficiently multiply or divide the orbital angular momentum(OAM)of light beams using a sequence of two optical elements.The key element is represented by an optical transformation mapping the azimuthal phase gradient of the input OAM beam onto a circular sector.By combining multiple circular-sector transformations into a single optical element,it is possible to multiply the value of the input OAM state by splitting and mapping the phase onto complementary circular sectors.Conversely,by combining multiple inverse transformations,the division of the initial OAM value is achievable by mapping distinct complementary circular sectors of the input beam into an equal number of circular phase gradients.Optical elements have been fabricated in the form of phase-only diffractive optics with high-resolution electron-beam lithography.Optical tests confirm the capability of the multiplier optics to perform integer multiplication of the input OAM,whereas the designed dividers are demonstrated to correctly split up the input beam into a complementary set of OAM beams.These elements can find applications for the multiplicative generation of higher-order OAM modes,optical information processing based on OAM beam transmission,and optical routing/switching in telecom.展开更多
A fungal consortium including Aspergillus niger, Mucor hiemalis and Galactomyces geotrichum was tested for the treatment of dairy wastewater. The bio-augmentation method was tested at lab-scale （4 L）, at pilot scale...A fungal consortium including Aspergillus niger, Mucor hiemalis and Galactomyces geotrichum was tested for the treatment of dairy wastewater. The bio-augmentation method was tested at lab-scale （4 L）, at pilot scale （110 L） and at an industrial scale in Wastewater Treatment Plants （WWTP）. The positive impact of fungal addition was confirmed when fungi was beforehand accelerated by pre-culture on whey （5 g/L lactose） or on the dairy effluent. Indeed, chemical oxygen demand （COD） removal yields increased from 55% to 75% for model medium, diluted milk. While after inoculation of an industrial biological tank from a dairy factory with the fungal consortium accelerated by pre-cultivation in a 1000 L pilot plant, the outlet COD values decreased from values above the standard one （100 mg/L） to values in the range of 50-70 mg/L. In addition, there was a clear impact of fungal addition on the ＇hard＇ or non-biodegradable COD owing to the significant reduction of the increase of the COD on BOD 5 ratio between the inlet and the outlet of the biological tank of WWTP. It was in the range of 451%-1111% before adding fungal consortium, and in the range of 257%-153% after bio-augmentation with fungi. An inoculated bioreactor with fungal consortium was developed at lab-scale and demonstrated successfully at pilot scale in WWTP.展开更多
文摘In this paper, a tractable solution is proposed to integrate, to a certain extent, market liquidity risk in the portfolio selection process. It is shown how an investor may take advantage of this additional risk source within the standard mean-variance optimization framework, by in certain circumstances overcoming the pitfalls of illiquidity and in others seizing a liquidity premium. Bid prices appear effective to capture liquidity risk. The efficient frontier conceived with bid prices consists of mean-variance optimal allocations that cover more liquid stocks （large caps） under stressed market conditions and less liquid stocks （small caps） under normal conditions.
文摘We present a method to efficiently multiply or divide the orbital angular momentum(OAM)of light beams using a sequence of two optical elements.The key element is represented by an optical transformation mapping the azimuthal phase gradient of the input OAM beam onto a circular sector.By combining multiple circular-sector transformations into a single optical element,it is possible to multiply the value of the input OAM state by splitting and mapping the phase onto complementary circular sectors.Conversely,by combining multiple inverse transformations,the division of the initial OAM value is achievable by mapping distinct complementary circular sectors of the input beam into an equal number of circular phase gradients.Optical elements have been fabricated in the form of phase-only diffractive optics with high-resolution electron-beam lithography.Optical tests confirm the capability of the multiplier optics to perform integer multiplication of the input OAM,whereas the designed dividers are demonstrated to correctly split up the input beam into a complementary set of OAM beams.These elements can find applications for the multiplicative generation of higher-order OAM modes,optical information processing based on OAM beam transmission,and optical routing/switching in telecom.
文摘A fungal consortium including Aspergillus niger, Mucor hiemalis and Galactomyces geotrichum was tested for the treatment of dairy wastewater. The bio-augmentation method was tested at lab-scale （4 L）, at pilot scale （110 L） and at an industrial scale in Wastewater Treatment Plants （WWTP）. The positive impact of fungal addition was confirmed when fungi was beforehand accelerated by pre-culture on whey （5 g/L lactose） or on the dairy effluent. Indeed, chemical oxygen demand （COD） removal yields increased from 55% to 75% for model medium, diluted milk. While after inoculation of an industrial biological tank from a dairy factory with the fungal consortium accelerated by pre-cultivation in a 1000 L pilot plant, the outlet COD values decreased from values above the standard one （100 mg/L） to values in the range of 50-70 mg/L. In addition, there was a clear impact of fungal addition on the ＇hard＇ or non-biodegradable COD owing to the significant reduction of the increase of the COD on BOD 5 ratio between the inlet and the outlet of the biological tank of WWTP. It was in the range of 451%-1111% before adding fungal consortium, and in the range of 257%-153% after bio-augmentation with fungi. An inoculated bioreactor with fungal consortium was developed at lab-scale and demonstrated successfully at pilot scale in WWTP.
