Amneet Singh - Academia.edu (original) (raw)

Papers by Amneet Singh

Bulletin of the American Physical Society, 2015

and balistiform swimmers are those which have an undulatory fin affixed to a rigid body unlike an... more and balistiform swimmers are those which have an undulatory fin affixed to a rigid body unlike anguilliforms who undulate their entire body. Is there a mechanical advantage to gymnotiform and balistiform swimming? This question was investigated by Lighthill & Blake in a four paper series Biofluiddynamics of balistiform and gymnotiform locomotion. We revisit this work using fully resolved numerical simulations of the types of swimmers considered by Lighthill & Blake to interrogate the issue of mechanical advantage for rigid body swimmers. In doing so, we find that while there is advantage to rigid body swimming, the mechanism of 'momentum enhancement,' proposed by Lighthill and Blake, is not the cause. Further, we use our results and simulations to explain why some gymnotiform and balistiform swimmers have their propulsor attached to their bodies at an angle.

Practical Applications, 2020

Practical Applications Summary In Diversification Benefits, Where Art Thou?, in the Winter 2019 e... more Practical Applications Summary In Diversification Benefits, Where Art Thou?, in the Winter 2019 edition of The Journal of Wealth Management, authors Sam Pittman, Amneet Singh, and Sangeetha Srinivasan, all of Russell Investments, consider how diversification may improve risk-adjusted returns (RARs) and what asset sectors may deliver those benefits. The authors examine whether exposure to some asset classes neutralizes the benefits from holding other asset classes, and how the returns from naive diversification match up to those from other approaches. Prompted by increasing investor skepticism over the advantages of diversification, the authors construct optimal fixed-weight portfolios with volatilities equal to those of three US-centric benchmark portfolios. They consider the historical benefits from diversifying into international equities, real assets, and below-investment-grade bonds. The authors draw from 15 different asset classes, to discern the regularity and magnitude of RAR improvement from diversification over five-year holding periods. They find that certain asset classes deliver diversification benefits more reliably than others; that some asset classes’ diversification benefits are dampened by the presence of other asset classes; and that portfolio returns from diversified holdings are subject to cyclicality that has longer wavelengths than the US business cycle. History implies the benefits of diversification will return, the authors note. TOPICS: Wealth management, retirement, portfolio construction

The Journal of Wealth Management, 2019

Following the global financial crisis, a portfolio concentrated in US large cap equity and aggreg... more Following the global financial crisis, a portfolio concentrated in US large cap equity and aggregate fixed income has provided higher returns than diversified portfolios through 2019. Such a prolonged experience causes investors to question the benefits of diversification. This leads us to use a longer history of data across 15 asset classes to understand the historical benefits of diversifying a portfolio with international equity, real assets, and below-investment-grade fixed income. The authors’ results portray the frequency and magnitude of risk-adjusted return improvement coming from different diversifying asset classes over five-year holding periods. The authors find that certain asset classes, such as below-investment-grade fixed income, regularly improve risk-adjusted return of the portfolio, while other asset classes like commodities improve risk-adjusted returns less frequently. Further, they observe that some asset classes do not deliver meaningful risk-adjusted return improvements in the presence of other asset classes. Their conclusion is that investors should continue to build diversified portfolios, but in doing so they should consider that some asset classes more consistently improved risk-adjusted returns than others. TOPICS: Wealth management, retirement, fixed-income portfolio management Key Findings • Certain asset classes, such as below-investment-grade fixed income, have provided consistent diversification benefits through time, while other asset classes, such as commodities (despite its low correlation to other asset classes), have less frequently improved portfolio performance. • Some asset classes have not delivered meaningful portfolio diversification benefits in the presence of other asset classes during the periods we examined. • We observe cyclicality in the improvement of portfolio returns from holding a more diversified portfolio. The periodicity appears longer than the US business cycle. Moreover, the time series of relative price-to-earnings ratios of US and international equity appears to move countercyclically with the outperformance of diversified portfolios.

Multimedia Tools and Applications, 2018

The image acquisition device, the light is filtered through a Color Filter Array (CFA), where eac... more The image acquisition device, the light is filtered through a Color Filter Array (CFA), where each pixel captures only one color (from Red, Green, and Blue), while others are calibrated. This process is known as interpolation process, and the artifacts introduced are called CFA or interpolation artifacts. The structure of these artifacts in the image is disturbed while a forgery is introduced in an image. In this paper, a high-order statistical approach is proposed to detect the inconsistencies in the artifacts of different parts of the image to expose any forgery present. The Markov Transition Probability Matrix (MTPM) is employed to develop various features that will detect the presence or absence of CFA artifacts in a particular region of the image. The Markov random process is applied because it provides an enhanced efficiency and reduced computational complexity for the forgery detection model. The algorithm is tested on 2 × 2 pixel block of the image which provides the results of a fine quality. There is no prior information of the location of the forged region of the image. The algorithm is tested on various images, taken from various social networking websites. The proposed forgery detection technique outperforms the existing state-of-the-art techniques for the different forgery scenarios by providing an average accuracy of 90.58%.

The Journal of Neuroscience, 2014

In this study, we investigated the development of endoplasmic reticulum (ER) stress after traumat... more In this study, we investigated the development of endoplasmic reticulum (ER) stress after traumatic brain injury (TBI) and the efficacy of post-TBI administration of docosahexaenoic acid (DHA) in reducing ER stress. TBI was induced by cortical contusion injury in Sprague-Dawley rats. Either DHA (16 mg/kg in DMSO) or vehicle DMSO (1 ml/kg) was administered intraperitoneally at 5 min after TBI, followed by a daily dose for 3–21 d. TBI triggered sustained expression of the ER stress marker proteins including phosphorylated eukaryotic initiation factor-2α, activating transcription factor 4, inositol requiring kinase 1, and C/EBP homologous protein in the ipsilateral cortex at 3–21 d after TBI. The prolonged ER stress was accompanied with an accumulation of abnormal ubiquitin aggregates and increased expression of amyloid precursor protein (APP) and phosphorylated tau (p-Tau) in the frontal cortex after TBI. The ER stress marker proteins were colocalized with APP accumulation in the soma...

Bulletin of the American Physical Society, 2015

and balistiform swimmers are those which have an undulatory fin affixed to a rigid body unlike an... more and balistiform swimmers are those which have an undulatory fin affixed to a rigid body unlike anguilliforms who undulate their entire body. Is there a mechanical advantage to gymnotiform and balistiform swimming? This question was investigated by Lighthill & Blake in a four paper series Biofluiddynamics of balistiform and gymnotiform locomotion. We revisit this work using fully resolved numerical simulations of the types of swimmers considered by Lighthill & Blake to interrogate the issue of mechanical advantage for rigid body swimmers. In doing so, we find that while there is advantage to rigid body swimming, the mechanism of 'momentum enhancement,' proposed by Lighthill and Blake, is not the cause. Further, we use our results and simulations to explain why some gymnotiform and balistiform swimmers have their propulsor attached to their bodies at an angle.

Practical Applications, 2020

Practical Applications Summary In Diversification Benefits, Where Art Thou?, in the Winter 2019 e... more Practical Applications Summary In Diversification Benefits, Where Art Thou?, in the Winter 2019 edition of The Journal of Wealth Management, authors Sam Pittman, Amneet Singh, and Sangeetha Srinivasan, all of Russell Investments, consider how diversification may improve risk-adjusted returns (RARs) and what asset sectors may deliver those benefits. The authors examine whether exposure to some asset classes neutralizes the benefits from holding other asset classes, and how the returns from naive diversification match up to those from other approaches. Prompted by increasing investor skepticism over the advantages of diversification, the authors construct optimal fixed-weight portfolios with volatilities equal to those of three US-centric benchmark portfolios. They consider the historical benefits from diversifying into international equities, real assets, and below-investment-grade bonds. The authors draw from 15 different asset classes, to discern the regularity and magnitude of RAR improvement from diversification over five-year holding periods. They find that certain asset classes deliver diversification benefits more reliably than others; that some asset classes’ diversification benefits are dampened by the presence of other asset classes; and that portfolio returns from diversified holdings are subject to cyclicality that has longer wavelengths than the US business cycle. History implies the benefits of diversification will return, the authors note. TOPICS: Wealth management, retirement, portfolio construction

The Journal of Wealth Management, 2019

Following the global financial crisis, a portfolio concentrated in US large cap equity and aggreg... more Following the global financial crisis, a portfolio concentrated in US large cap equity and aggregate fixed income has provided higher returns than diversified portfolios through 2019. Such a prolonged experience causes investors to question the benefits of diversification. This leads us to use a longer history of data across 15 asset classes to understand the historical benefits of diversifying a portfolio with international equity, real assets, and below-investment-grade fixed income. The authors’ results portray the frequency and magnitude of risk-adjusted return improvement coming from different diversifying asset classes over five-year holding periods. The authors find that certain asset classes, such as below-investment-grade fixed income, regularly improve risk-adjusted return of the portfolio, while other asset classes like commodities improve risk-adjusted returns less frequently. Further, they observe that some asset classes do not deliver meaningful risk-adjusted return improvements in the presence of other asset classes. Their conclusion is that investors should continue to build diversified portfolios, but in doing so they should consider that some asset classes more consistently improved risk-adjusted returns than others. TOPICS: Wealth management, retirement, fixed-income portfolio management Key Findings • Certain asset classes, such as below-investment-grade fixed income, have provided consistent diversification benefits through time, while other asset classes, such as commodities (despite its low correlation to other asset classes), have less frequently improved portfolio performance. • Some asset classes have not delivered meaningful portfolio diversification benefits in the presence of other asset classes during the periods we examined. • We observe cyclicality in the improvement of portfolio returns from holding a more diversified portfolio. The periodicity appears longer than the US business cycle. Moreover, the time series of relative price-to-earnings ratios of US and international equity appears to move countercyclically with the outperformance of diversified portfolios.

Multimedia Tools and Applications, 2018

The image acquisition device, the light is filtered through a Color Filter Array (CFA), where eac... more The image acquisition device, the light is filtered through a Color Filter Array (CFA), where each pixel captures only one color (from Red, Green, and Blue), while others are calibrated. This process is known as interpolation process, and the artifacts introduced are called CFA or interpolation artifacts. The structure of these artifacts in the image is disturbed while a forgery is introduced in an image. In this paper, a high-order statistical approach is proposed to detect the inconsistencies in the artifacts of different parts of the image to expose any forgery present. The Markov Transition Probability Matrix (MTPM) is employed to develop various features that will detect the presence or absence of CFA artifacts in a particular region of the image. The Markov random process is applied because it provides an enhanced efficiency and reduced computational complexity for the forgery detection model. The algorithm is tested on 2 × 2 pixel block of the image which provides the results of a fine quality. There is no prior information of the location of the forged region of the image. The algorithm is tested on various images, taken from various social networking websites. The proposed forgery detection technique outperforms the existing state-of-the-art techniques for the different forgery scenarios by providing an average accuracy of 90.58%.

The Journal of Neuroscience, 2014

In this study, we investigated the development of endoplasmic reticulum (ER) stress after traumat... more In this study, we investigated the development of endoplasmic reticulum (ER) stress after traumatic brain injury (TBI) and the efficacy of post-TBI administration of docosahexaenoic acid (DHA) in reducing ER stress. TBI was induced by cortical contusion injury in Sprague-Dawley rats. Either DHA (16 mg/kg in DMSO) or vehicle DMSO (1 ml/kg) was administered intraperitoneally at 5 min after TBI, followed by a daily dose for 3–21 d. TBI triggered sustained expression of the ER stress marker proteins including phosphorylated eukaryotic initiation factor-2α, activating transcription factor 4, inositol requiring kinase 1, and C/EBP homologous protein in the ipsilateral cortex at 3–21 d after TBI. The prolonged ER stress was accompanied with an accumulation of abnormal ubiquitin aggregates and increased expression of amyloid precursor protein (APP) and phosphorylated tau (p-Tau) in the frontal cortex after TBI. The ER stress marker proteins were colocalized with APP accumulation in the soma...