Robert Jennings - Academia.edu (original) (raw)
Papers by Robert Jennings
The Journal of Cell Biology, 1967
This paper describes the morphology and photosynthetic activity of a mutant of Chlamy-domonas rei... more This paper describes the morphology and photosynthetic activity of a mutant of Chlamy-domonas reinhardi (yl) which is unable to synthesize chlorophyll in the dark. When grown heterotrophically in the light, the mutant is indistinguishable from the wild type ...
Biochemistry, 2006
The time-resolved fluorescence decay of plant PSI-LHCI has been analyzed and compared with its co... more The time-resolved fluorescence decay of plant PSI-LHCI has been analyzed and compared with its component parts, the PSI core and the peripheral antenna LHCI, in an attempt to (i) define the physical domains associated with the multicomponent decay-associated spectra (DAS) and determine the origin of the kinetically slow steps responsible for them, (ii) formulate a clear working hypothesis for the positive decay-associated spectral amplitudes of the two slowest decay components, and (iii) determine the impact of the peripheral antenna complexes (LHCI) on the effective trapping rate for the photosystem. The results for PSI-LHCI indicate that the three exponential component DAS description, previously reported in the literature, is not numerically unique. The fit minimum is rather broad, which necessitated the introduction of other fit criteria in addition to the purely numerical one. The analysis demonstrates that (i) the physical domains associated with the multicomponent decay are associated with the antenna and particularly with the low-energy spectral forms, (ii) the positive DAS amplitudes of the two slowest decay components are suggested to be due to energy transfer kinetic heterogeneity to different F735 low-energy forms, and (iii) the peripheral antenna slows down the effective photosystem photochemical rate by about 3 times, and this is approximately half due to antenna degeneracy and half due to the low-energy forms.
Kidney Int, 1973
... Correspondence: Dr Robert B Jennings, Department of Pathology, Northwestern University Medica... more ... Correspondence: Dr Robert B Jennings, Department of Pathology, Northwestern University Medical School, 303 ... London, Academic Press, 1963; Herdson PB, Jennings RB, Earle DP: Glomerular fine ... Paris), 118:10151025, 1967; Hendrickse RG, Glasgow EF, Adeniyi A, White ...
ABSTRACT This paper empirically decomposes private benefits of control into two components: benef... more ABSTRACT This paper empirically decomposes private benefits of control into two components: benefits accruing to managers and benefits accruing to owners. It documents that private benefits of control, as measured by block premium, increases slowly with respect to the ownership level, as measured by the percentage of shares acquired in block trade, but increases rapidly with respect to the likelihood of exercising managerial control of the firm, as measured by the probability of top executive turnover following block trade. To illustrate, for a ten-percent block trade, the block premium is 1.20%, 5.75%, 12.80% if there is a zero-percent, twenty five-percent, fifty-percent likelihood of subsequent top executive turnover, respectively. This indicates that managers enjoy more private benefits than owners., for helpful comments. All errors remain my responsibility.
SUMMARY: We describe a method of performing lower cervical nerve root block (CNRB) with CT fluoro... more SUMMARY: We describe a method of performing lower cervical nerve root block (CNRB) with CT fluoroscopy in patients with large body habitus using the swimmer's position. This approach reduces image noise with acceptable visualization of vital structures and improved foraminal/root access. Anticipated use of the swimmer's position coupled with minimally modified radiation exposure parameters can limit radiation dose to operator/patient
Using New York Stock Exchange order data, we examine the determinants of order choices. We consid... more Using New York Stock Exchange order data, we examine the determinants of order choices. We consider order type (market and limit), order side, automatic execution vs. the auction process, order pricing aggressiveness, order cancellation, and the passage of time ...
Recent and Future Developments in Medical Imaging II, 1979
The Energy Citations Database (ECD) provides access to historical and current research (1948 to t... more The Energy Citations Database (ECD) provides access to historical and current research (1948 to the present) from the Department of Energy (DOE) and predecessor agencies.
Journal of Electrocardiology, 2015
Previous studies have shown that QRS prolongation is a sign of depressed collateral flow and incr... more Previous studies have shown that QRS prolongation is a sign of depressed collateral flow and increased rate of myocardial cell death during coronary occlusion. The aims of this study were to evaluate ischemic QRS prolongation as a biomarker of severe ischemia by establishing the relationship between prolongation and collateral flow experimentally in a dog model, and test if the same pattern of ischemic QRS prolongation occurs in man. Degree of ischemic QRS prolongation was measured using a novel method in dogs (n=23) and patients (n=52) during coronary occlusion for 5min. Collateral arterial flow was assessed in the dogs. There was a significant correlation between QRS prolongation and collateral flow in dogs (r=0.61, p=0.008). Magnitude and temporal evolution of prolongation during ischemia were similar for dogs and humans (p=0.202 and p=0.911). Quantification of ischemic QRS prolongation could potentially be used as a biomarker for severe myocardial ischemia.
Medical Physics, Nov 1, 2004
Noise transfer in granular x-ray imaging phosphor screens is not proportional to the square of th... more Noise transfer in granular x-ray imaging phosphor screens is not proportional to the square of the magnitude of the signal transfer when the transfer properties are considered for the entire screen thickness, unless appropriately weighted at each depth of interaction. This property, known as the Lubberts effect, has not yet been studied in columnar structured screens because of a lack of a generalized description of the depth-dependent light transport. In this paper, we investigate the signal and noise transfer characteristics of columnar phosphors used in digital mammography detectors using DETECT-II, an optical Monte Carlo light transport simulation code. We first validate our choice of optical parameters for the description of granular and columnar screens using published normalized modulation transfer (MTF) experimental data. Our calculations of MTF match empirically measured MTFs for a granular film/screen analog system, and for an indirect x-ray digital imaging system with CsI:Tl screen representative of digital mammography systems. Using the depth-dependent spread functions and collection efficiencies, we calculate the signal and noise transfer functions and the Lubberts fraction, which is the ratio of the signal transfer function to the noise transfer function, for different screen thicknesses of granular and columnar phosphors. We find that the Lubberts fraction of a 85 microm granular screen model corresponding to a Gd2O2S:Tb screen is similar to the fraction for a 100 microm columnar CsI:Tl screen.
The American Journal of Pathology, Mar 1, 1965
Page 1. A COMPARATIVE STUDY OF THE FINE STRUCTURE OF NORMAL AND ISCHEMIC DOG MYOCARDIUM WITH SPEC... more Page 1. A COMPARATIVE STUDY OF THE FINE STRUCTURE OF NORMAL AND ISCHEMIC DOG MYOCARDIUM WITH SPECIAL REFERENCE TO EARLY CHANGES FOLLOWING TEMPORARY OCCLUSION OF A CORONARY ARTERY ...
Progress in Biomedical Optics and Imaging, Feb 26, 2009
For the last few years, development and optimization of three-dimensional (3D) x-ray breast imagi... more For the last few years, development and optimization of three-dimensional (3D) x-ray breast imaging systems, such as breast tomosynthesis and computed tomography, has drawn much attention from the medical imaging community, either academia or industry. However, the trade offs between patient safety and the efficacy of the devices have yet to be investigated with use of objective performance metrics. Moreover, as the 3D imaging systems give depth information that was not available in planar mammography, standard mammography quality assurance and control (QA/QC) phantoms used for measuring system performance are not appropriate since they do not account for background variability and clinically relevant tasks. Therefore, it is critical to develop QA/QC methods that incorporate background variability with use of a task-based statistical assessment methodology.1 In this work, we develop a physical phantom that simulates variable backgrounds using spheres of different sizes and densities, and present an evaluation method based on statistical decision theory,2 in particular, with use of the ideal linear observer, for evaluating planar and 3D x-ray breast imaging systems. We demonstrate our method for a mammography system and compare the variable phantom case to that of a phantom of the same dimensions filled with water. Preliminary results show that measuring the system's detection performance without consideration of background variability may lead to misrepresentation of system performance.
We perform a comprehensive test of order choice theory from a sample period when the NYSE trades ... more We perform a comprehensive test of order choice theory from a sample period when the NYSE trades in decimals and allows automatic executions. We analyze the decision to submit or cancel an order or to take no action. For submitted orders we distinguish order type (market vs. limit), order side (buy vs. sell), execution method (floor vs. automatic), and order pricing aggressiveness. We use a multinomial logit specification and a new statistical test. We find a negative autocorrelation in changes in order flow exists over five-minute intervals supporting dynamic limit order book theory, despite a positive first-order autocorrelation in order type. Orders routed to the NYSE's floor are sensitive to market conditions (e.g., spread, depth, volume, volatility, market and individual-stock returns, and private information), but those using the automatic execution system (Direct+) are insensitive to market conditions. When the quoted depth is large, traders are more likely to "jump the queue" by submitting limit orders with limit prices bettering existing quotes. Aggressively-priced limit orders are more likely late in the trading day providing evidence in support of prior experimental results. JEL Classification Code: G10
Analytical expressions have been written for image quality in mammography. Multiparameter optimiz... more Analytical expressions have been written for image quality in mammography. Multiparameter optimizations have been conducted to find mammography systems providing the lowest patient dose for a given image quality. The optimizations are subject to constraints imposed by technology, such as power limits on the tube focal spot, absorption efficiency related to detector resolution, and others. The optimizations permit system geometry,
The periodic assessment of exposures in diagnostic radiology is an important part of a comprehens... more The periodic assessment of exposures in diagnostic radiology is an important part of a comprehensive quality assurance program. The most frequent radiologic examination conducted in the United States is chest radiography. Automatic exposure controlled (AEC) techniques are often used for this exam, and a standard patient-equivalent chest phantom is useful when estimating patient exposures on such systems. This is of
A study is presented of the angular distribution of scattered radiation at low energies for angle... more A study is presented of the angular distribution of scattered radiation at low energies for angles between 2 degrees and 15 degrees from the outward normal to the exit surface of several phantoms, with 1 degree resolution. A cryogenically cooled germanium detector was used to measure the spectra of the scattered radiation. The differential scattering fluences, or numbers of photons
SSRN Electronic Journal, 2000
ABSTRACT We identify retail brokers that seemingly route orders to maximize order flow payments: ... more ABSTRACT We identify retail brokers that seemingly route orders to maximize order flow payments: selling market orders and routing limit orders to venues paying large liquidity rebates. Because venues offering high rebates also charge liquidity demanding investors high fees, fee structure may affect the arrival rate of marketable orders. If limit orders on low-fee venues fill when similarly priced orders on high-fee venues do not, routing orders to maximize rebates might not always be in customers’ best interests. Using proprietary limit order data, we document a negative relation between several measures of limit order execution quality and the relative fee level. Specifically, we show that when ‘identical’ limit orders are concurrently displayed on two venues, orders routed to the low-fee venue execute more frequently and suffer lower adverse selection. Using the NYSE’s TAQ data, we show that the negative relation between take fees and execution quality extends beyond our proprietary dataset.
The Journal of Cell Biology, 1967
This paper describes the morphology and photosynthetic activity of a mutant of Chlamy-domonas rei... more This paper describes the morphology and photosynthetic activity of a mutant of Chlamy-domonas reinhardi (yl) which is unable to synthesize chlorophyll in the dark. When grown heterotrophically in the light, the mutant is indistinguishable from the wild type ...
Biochemistry, 2006
The time-resolved fluorescence decay of plant PSI-LHCI has been analyzed and compared with its co... more The time-resolved fluorescence decay of plant PSI-LHCI has been analyzed and compared with its component parts, the PSI core and the peripheral antenna LHCI, in an attempt to (i) define the physical domains associated with the multicomponent decay-associated spectra (DAS) and determine the origin of the kinetically slow steps responsible for them, (ii) formulate a clear working hypothesis for the positive decay-associated spectral amplitudes of the two slowest decay components, and (iii) determine the impact of the peripheral antenna complexes (LHCI) on the effective trapping rate for the photosystem. The results for PSI-LHCI indicate that the three exponential component DAS description, previously reported in the literature, is not numerically unique. The fit minimum is rather broad, which necessitated the introduction of other fit criteria in addition to the purely numerical one. The analysis demonstrates that (i) the physical domains associated with the multicomponent decay are associated with the antenna and particularly with the low-energy spectral forms, (ii) the positive DAS amplitudes of the two slowest decay components are suggested to be due to energy transfer kinetic heterogeneity to different F735 low-energy forms, and (iii) the peripheral antenna slows down the effective photosystem photochemical rate by about 3 times, and this is approximately half due to antenna degeneracy and half due to the low-energy forms.
Kidney Int, 1973
... Correspondence: Dr Robert B Jennings, Department of Pathology, Northwestern University Medica... more ... Correspondence: Dr Robert B Jennings, Department of Pathology, Northwestern University Medical School, 303 ... London, Academic Press, 1963; Herdson PB, Jennings RB, Earle DP: Glomerular fine ... Paris), 118:10151025, 1967; Hendrickse RG, Glasgow EF, Adeniyi A, White ...
ABSTRACT This paper empirically decomposes private benefits of control into two components: benef... more ABSTRACT This paper empirically decomposes private benefits of control into two components: benefits accruing to managers and benefits accruing to owners. It documents that private benefits of control, as measured by block premium, increases slowly with respect to the ownership level, as measured by the percentage of shares acquired in block trade, but increases rapidly with respect to the likelihood of exercising managerial control of the firm, as measured by the probability of top executive turnover following block trade. To illustrate, for a ten-percent block trade, the block premium is 1.20%, 5.75%, 12.80% if there is a zero-percent, twenty five-percent, fifty-percent likelihood of subsequent top executive turnover, respectively. This indicates that managers enjoy more private benefits than owners., for helpful comments. All errors remain my responsibility.
SUMMARY: We describe a method of performing lower cervical nerve root block (CNRB) with CT fluoro... more SUMMARY: We describe a method of performing lower cervical nerve root block (CNRB) with CT fluoroscopy in patients with large body habitus using the swimmer's position. This approach reduces image noise with acceptable visualization of vital structures and improved foraminal/root access. Anticipated use of the swimmer's position coupled with minimally modified radiation exposure parameters can limit radiation dose to operator/patient
Using New York Stock Exchange order data, we examine the determinants of order choices. We consid... more Using New York Stock Exchange order data, we examine the determinants of order choices. We consider order type (market and limit), order side, automatic execution vs. the auction process, order pricing aggressiveness, order cancellation, and the passage of time ...
Recent and Future Developments in Medical Imaging II, 1979
The Energy Citations Database (ECD) provides access to historical and current research (1948 to t... more The Energy Citations Database (ECD) provides access to historical and current research (1948 to the present) from the Department of Energy (DOE) and predecessor agencies.
Journal of Electrocardiology, 2015
Previous studies have shown that QRS prolongation is a sign of depressed collateral flow and incr... more Previous studies have shown that QRS prolongation is a sign of depressed collateral flow and increased rate of myocardial cell death during coronary occlusion. The aims of this study were to evaluate ischemic QRS prolongation as a biomarker of severe ischemia by establishing the relationship between prolongation and collateral flow experimentally in a dog model, and test if the same pattern of ischemic QRS prolongation occurs in man. Degree of ischemic QRS prolongation was measured using a novel method in dogs (n=23) and patients (n=52) during coronary occlusion for 5min. Collateral arterial flow was assessed in the dogs. There was a significant correlation between QRS prolongation and collateral flow in dogs (r=0.61, p=0.008). Magnitude and temporal evolution of prolongation during ischemia were similar for dogs and humans (p=0.202 and p=0.911). Quantification of ischemic QRS prolongation could potentially be used as a biomarker for severe myocardial ischemia.
Medical Physics, Nov 1, 2004
Noise transfer in granular x-ray imaging phosphor screens is not proportional to the square of th... more Noise transfer in granular x-ray imaging phosphor screens is not proportional to the square of the magnitude of the signal transfer when the transfer properties are considered for the entire screen thickness, unless appropriately weighted at each depth of interaction. This property, known as the Lubberts effect, has not yet been studied in columnar structured screens because of a lack of a generalized description of the depth-dependent light transport. In this paper, we investigate the signal and noise transfer characteristics of columnar phosphors used in digital mammography detectors using DETECT-II, an optical Monte Carlo light transport simulation code. We first validate our choice of optical parameters for the description of granular and columnar screens using published normalized modulation transfer (MTF) experimental data. Our calculations of MTF match empirically measured MTFs for a granular film/screen analog system, and for an indirect x-ray digital imaging system with CsI:Tl screen representative of digital mammography systems. Using the depth-dependent spread functions and collection efficiencies, we calculate the signal and noise transfer functions and the Lubberts fraction, which is the ratio of the signal transfer function to the noise transfer function, for different screen thicknesses of granular and columnar phosphors. We find that the Lubberts fraction of a 85 microm granular screen model corresponding to a Gd2O2S:Tb screen is similar to the fraction for a 100 microm columnar CsI:Tl screen.
The American Journal of Pathology, Mar 1, 1965
Page 1. A COMPARATIVE STUDY OF THE FINE STRUCTURE OF NORMAL AND ISCHEMIC DOG MYOCARDIUM WITH SPEC... more Page 1. A COMPARATIVE STUDY OF THE FINE STRUCTURE OF NORMAL AND ISCHEMIC DOG MYOCARDIUM WITH SPECIAL REFERENCE TO EARLY CHANGES FOLLOWING TEMPORARY OCCLUSION OF A CORONARY ARTERY ...
Progress in Biomedical Optics and Imaging, Feb 26, 2009
For the last few years, development and optimization of three-dimensional (3D) x-ray breast imagi... more For the last few years, development and optimization of three-dimensional (3D) x-ray breast imaging systems, such as breast tomosynthesis and computed tomography, has drawn much attention from the medical imaging community, either academia or industry. However, the trade offs between patient safety and the efficacy of the devices have yet to be investigated with use of objective performance metrics. Moreover, as the 3D imaging systems give depth information that was not available in planar mammography, standard mammography quality assurance and control (QA/QC) phantoms used for measuring system performance are not appropriate since they do not account for background variability and clinically relevant tasks. Therefore, it is critical to develop QA/QC methods that incorporate background variability with use of a task-based statistical assessment methodology.1 In this work, we develop a physical phantom that simulates variable backgrounds using spheres of different sizes and densities, and present an evaluation method based on statistical decision theory,2 in particular, with use of the ideal linear observer, for evaluating planar and 3D x-ray breast imaging systems. We demonstrate our method for a mammography system and compare the variable phantom case to that of a phantom of the same dimensions filled with water. Preliminary results show that measuring the system's detection performance without consideration of background variability may lead to misrepresentation of system performance.
We perform a comprehensive test of order choice theory from a sample period when the NYSE trades ... more We perform a comprehensive test of order choice theory from a sample period when the NYSE trades in decimals and allows automatic executions. We analyze the decision to submit or cancel an order or to take no action. For submitted orders we distinguish order type (market vs. limit), order side (buy vs. sell), execution method (floor vs. automatic), and order pricing aggressiveness. We use a multinomial logit specification and a new statistical test. We find a negative autocorrelation in changes in order flow exists over five-minute intervals supporting dynamic limit order book theory, despite a positive first-order autocorrelation in order type. Orders routed to the NYSE's floor are sensitive to market conditions (e.g., spread, depth, volume, volatility, market and individual-stock returns, and private information), but those using the automatic execution system (Direct+) are insensitive to market conditions. When the quoted depth is large, traders are more likely to "jump the queue" by submitting limit orders with limit prices bettering existing quotes. Aggressively-priced limit orders are more likely late in the trading day providing evidence in support of prior experimental results. JEL Classification Code: G10
Analytical expressions have been written for image quality in mammography. Multiparameter optimiz... more Analytical expressions have been written for image quality in mammography. Multiparameter optimizations have been conducted to find mammography systems providing the lowest patient dose for a given image quality. The optimizations are subject to constraints imposed by technology, such as power limits on the tube focal spot, absorption efficiency related to detector resolution, and others. The optimizations permit system geometry,
The periodic assessment of exposures in diagnostic radiology is an important part of a comprehens... more The periodic assessment of exposures in diagnostic radiology is an important part of a comprehensive quality assurance program. The most frequent radiologic examination conducted in the United States is chest radiography. Automatic exposure controlled (AEC) techniques are often used for this exam, and a standard patient-equivalent chest phantom is useful when estimating patient exposures on such systems. This is of
A study is presented of the angular distribution of scattered radiation at low energies for angle... more A study is presented of the angular distribution of scattered radiation at low energies for angles between 2 degrees and 15 degrees from the outward normal to the exit surface of several phantoms, with 1 degree resolution. A cryogenically cooled germanium detector was used to measure the spectra of the scattered radiation. The differential scattering fluences, or numbers of photons
SSRN Electronic Journal, 2000
ABSTRACT We identify retail brokers that seemingly route orders to maximize order flow payments: ... more ABSTRACT We identify retail brokers that seemingly route orders to maximize order flow payments: selling market orders and routing limit orders to venues paying large liquidity rebates. Because venues offering high rebates also charge liquidity demanding investors high fees, fee structure may affect the arrival rate of marketable orders. If limit orders on low-fee venues fill when similarly priced orders on high-fee venues do not, routing orders to maximize rebates might not always be in customers’ best interests. Using proprietary limit order data, we document a negative relation between several measures of limit order execution quality and the relative fee level. Specifically, we show that when ‘identical’ limit orders are concurrently displayed on two venues, orders routed to the low-fee venue execute more frequently and suffer lower adverse selection. Using the NYSE’s TAQ data, we show that the negative relation between take fees and execution quality extends beyond our proprietary dataset.
Bentham Science Publishers
Oxygenic photosynthesis is indispensable both for the development and maintenance of life on eart... more Oxygenic photosynthesis is indispensable both for the development and maintenance of life on earth by converting
light energy into chemical energy and by producing molecular oxygen and consuming carbon dioxide. This latter
process has been responsible for reducing the CO2 from its very high levels in the primitive atmosphere to the present low
levels and thus reducing global temperatures to levels conducive to the development of life. Photosystem I and photosystem
II are the two multi-protein complexes that contain the pigments necessary to harvest photons and use light energy to
catalyse the primary photosynthetic endergonic reactions producing high energy compounds. Both photosystems are
highly organised membrane supercomplexes composed of a core complex, containing the reaction centre where electron
transport is initiated, and of a peripheral antenna system, which is important for light harvesting and photosynthetic activity
regulation. If on the one hand both the chemical reactions catalysed by the two photosystems and their detailed structure
are different, on the other hand they share many similarities. In this review we discuss and compare various aspects of
the organisation, functioning and regulation of plant photosystems by comparing them for similarities and differences as
obtained by structural, biochemical and spectroscopic investigations.