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114 results on '"Martin, David G."'

1. Measurement-induced phase transition in a single-body tight-binding model

Author

Jin, Tony and Martin, David G.

Subjects
Quantum Physics, Condensed Matter - Statistical Mechanics
Abstract

We study the statistical properties of a single free quantum particle evolving coherently on a discrete lattice in ${\rm d}$ spatial dimensions where every lattice site is additionally subject to continuous measurement of the occupation number. Our numerical results indicate that the system undergoes a Measurement-induced Phase Transition (MiPT) for ${\rm d}>1$ from a $\textit{delocalized}$ to a $\textit{localized}$ phase as the measurement strength $\gamma$ is increased beyond a critical value $\gamma_{c}$. In the language of surface growth, the delocalized phase corresponds to a $\textit{smooth}$ phase while the localized phase corresponds to a $\textit{rough}$ phase. We support our numerical results with perturbative renormalization group (RG) computations which are in qualitative agreement at one-loop order., Comment: 5 pages, 5 figures, 1 table + Supplemental Material

Published
2023
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2. KPZ physics and phase transition in a classical single random walker under continuous measurement

Author

Jin, Tony and Martin, David G.

Subjects
Condensed Matter - Statistical Mechanics
Abstract

We introduce and study a new model consisting of a single classical random walker undergoing continuous monitoring at rate $\gamma$ on a discrete lattice. Although such a continuous measurement cannot affect physical observables, it has a non-trivial effect on the probability distribution of the random walker. At small $\gamma$, we show analytically that the time-evolution of the latter can be mapped to the Stochastic Heat Equation (SHE). In this limit, the width of the log probability thus follows a Family-Vicsek scaling law, $N^{\alpha}f(t/N^{\alpha/\beta})$, with roughness and growth exponents corresponding to the Kardar-Parisi-Zhang (KPZ) universality class, i.e $\alpha^{\rm{1D}}_{\rm{KPZ}}=1/2$ and $\beta^{\rm{1D}}_{\rm{KPZ}}=1/3$ respectively. When $\gamma$ is increased outside this regime, we find numerically in 1D a crossover from the KPZ class to a new universality class characterized by exponents $\alpha^{1\rm{D}}_{\text{M}}\approx 1$ and $\beta^{1\rm{D}}_{\text{M}}\approx 1.4$. In 3D, varying $\gamma$ beyond a critical value $\gamma^c_{\rm{M}}$ leads to a phase transition from a smooth phase that we identify as the Edwards-Wilkinson (EW) class to a new universality class with $\alpha^{3\rm{D}}_{\text{M}}\approx1$., Comment: 9 pages, 3 figures

Published
2022
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5. St Andrew's COVID-19 surgery safety (StACS) study: Elective plastic surgery, trauma & burns

Author

Ahmad, Fateh, Banwell, Miles E, Barnes, David E, El-Muttardi, Naguib, Griffiths, Matthew, Hussain, Amer, Iwuagwu, Fortune C, Kangesu, Loshan, Khan, Waseem, Martin, Niall, Mopuri, Nabil, Morgan, Mary, Morris, Paul, Rorison, Patricia, Shelley, Odhran, Sierakowski, Adam, Tare, Makarand, Tzafetta, Kallirroi, Zweifel, Claire J, Appukuttan, Aswin, Balgaumwala, Tasneem, Counter, Oliver, Deelip Dhake, Swapnil, Fernandez-Diaz, Oscar F, Gathura, Esther, Harris, Nicola, Constantin Ion Jica, Romulus, Katechia, Devvrat, Lavender, Scott, Martin, David G, Mertic, Alex, Miranda, Adela, Myers, Jo, Nasrallah, Fady, Pantelides, Nicholas, Prior, Sheila, Raveendran, Sreekanth, Sell, Tracey, Sinha, Reetu, Smeeton, Ben T, Smith, Alex C D, Sofos, Stratos, Strong, Ben, Tang, Jasmine Y M, Thacoor, Amitabh, Tucker, Anne, Turkentine, Michele, Cornforth, Mark, Cowdery, Sally, Marasca, Alessandro, Palmer, Helen, Watts, Carole, Watts, Jan, Wiltshire, Rachel, Sing, Quillan Young, Zberea, Diana E, Mabvuure, Nigel T, Miranda, B.H., Hughes, W.R.M., Pinto-Lopes, R., Mathur, B.S., Ramakrishnan, V.V., and Sood, M.K.

Published
2021
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6. High precision angle calibration for spherical measurement systems

Author

Martin, David G.

Subjects
620, TK Electrical engineering. Electronics Nuclear engineering, QC Physics
Abstract

The European Synchrotron Radiation Facility (ESRF) located in Grenoble, France is a joint facility supported and shared by 19 European countries. It operates the most powerful synchrotron radiation source in Europe. Synchrotron radiation sources address many important questions in modern science and technology. They can be compared to “super microscopes”, revealing invaluable information in numerous fields of diverse research such as physics, medicine, biology, geophysics and archaeology. For the ESRF accelerators and beam lines to work correctly, alignment is of critical importance. Alignment tolerances are typically much less than one millimetre and often in the order of several micrometers over the 844 m ESRF storage ring circumference. To help maintain these tolerances, the ESRF has, and continues to develop calibration techniques for high precision spherical measurement system (SMS) instruments. SMSs are a family of instruments comprising automated total stations (theodolites equipped with distance meters), referred to here as robotic total stations (RTSs); and laser trackers (LTs). The ESRF has a modern distance meter calibration bench (DCB) used for the calibration of SMS electronic distance meters. At the limit of distance meter precision, the only way to improve positional uncertainty in the ESRF alignment is to improve the angle measuring capacity of these instruments. To this end, the horizontal circle comparator (HCC) and the vertical circle comparator (VCC) have been developed. Specifically, the HCC and VCC are used to calibrate the horizontal and vertical circle readings of SMS instruments under their natural working conditions. Combined with the DCB, the HCC and VCC provide a full calibration suite for SMS instruments. This thesis presents their development, functionality and in depth uncertainty evaluation. Several unique challenges are addressed in this work. The first is the development and characterization of the linked encoders configuration (LEC). This system, based on two continuously rotating angle encoders, is designed improve performance by eliminating residual encoder errors. The LEC can measure angle displacements with an estimated uncertainty of at least 0.044 arc seconds. Its uncertainty is presently limited by the instrumentation used to evaluate it. Secondly, in depth investigation has lead to the discovery of previously undocumented error-motion effects in ultra-precision angle calibration. Finally, methods for rigorous characterisation and extraction of rotary table error motions and their uncertainty evaluation using techniques not previously discussed in the literature have been developed.

Published
2009

7. Exertional Heat Stroke Survival at the Falmouth Road Race: 180 New Cases With Expanded Analysis.

Author

Stearns, Rebecca L., Hosokawa, Yuri, Belval, Luke N., Martin, David G., Huggins, Robert A., Jardine, John F., and Casa, Douglas J.

Subjects
HEAT stroke -- Risk factors, RISK assessment, PEARSON correlation (Statistics), RUNNING, DESCRIPTIVE statistics, EMERGENCY medical services, RETROSPECTIVE studies, MANN Whitney U Test, IMMERSION in liquids, SPORTS events, RESEARCH methodology, MEDICAL records, ACQUISITION of data, SURVIVAL analysis (Biometry), DATA analysis software, EPIDEMIOLOGICAL research
Abstract

A high number of exertional heat stroke (EHS) cases occur during the Falmouth Road Race. To extend previous analyses of EHS cases during the Falmouth Road Race by assessing or describing (1) EHS and heat exhaustion (HE) incidence rates, (2) EHS outcomes as they relate to survival, (3) the effect of the environment on these outcomes, and (4) how this influences medical provider planning and preparedness. Descriptive epidemiologic study. Falmouth Road Race. Patients with EHS or HE admitted to the medical tent. We obtained 8 years (2012 to 2019) of Falmouth Road Race anonymous EHS and HE medical records. Meteorologic data were collected and analyzed to evaluate the effect of environmental conditions on the heat illness incidence (exertional heat illness [EHI] = EHS + HE). The EHS treatment and outcomes (ie, cooling time, survival, and discharge outcome), number of HE patients, and wet bulb globe temperature (WBGT) for each race were analyzed. A total of 180 EHS and 239 HE cases were identified. Overall incidence rates per 1000 participants were 2.07 for EHS and 2.76 for HE. The EHI incidence rate was 4.83 per 1000 participants. Of the 180 EHS cases, 100% survived, and 20% were transported to the emergency department. The WBGT was strongly correlated with the incidence of both EHS (r2 = 0.904, P =.026) and EHI (r2 = 0.912, P =.023). This is the second-largest civilian database of EHS cases reported. When combined with the previous dataset of EHS survivors from this race, it amounts to 454 EHS cases resulting in 100% survival. The WBGT remained a strong predictor of EHS and EHI cases. These findings support 100% survival from EHS when patients over a wide range of ages and sexes are treated with cold-water immersion. [ABSTRACT FROM AUTHOR]

Published
2024
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10. St Andrew's COVID-19 surgery safety (StACS) study: Elective plastic surgery, trauma & burns

Author

Miranda, B.H., primary, Hughes, W.R.M., additional, Pinto-Lopes, R., additional, Mathur, B.S., additional, Ramakrishnan, V.V., additional, Sood, M.K., additional, Ahmad, Fateh, additional, Banwell, Miles E, additional, Barnes, David E, additional, El-Muttardi, Naguib, additional, Griffiths, Matthew, additional, Hussain, Amer, additional, Iwuagwu, Fortune C, additional, Kangesu, Loshan, additional, Khan, Waseem, additional, Martin, Niall, additional, Mopuri, Nabil, additional, Morgan, Mary, additional, Morris, Paul, additional, Rorison, Patricia, additional, Shelley, Odhran, additional, Sierakowski, Adam, additional, Tare, Makarand, additional, Tzafetta, Kallirroi, additional, Zweifel, Claire J, additional, Appukuttan, Aswin, additional, Balgaumwala, Tasneem, additional, Counter, Oliver, additional, Deelip Dhake, Swapnil, additional, Fernandez-Diaz, Oscar F, additional, Gathura, Esther, additional, Harris, Nicola, additional, Constantin Ion Jica, Romulus, additional, Katechia, Devvrat, additional, Lavender, Scott, additional, Martin, David G, additional, Mertic, Alex, additional, Miranda, Adela, additional, Myers, Jo, additional, Nasrallah, Fady, additional, Pantelides, Nicholas, additional, Prior, Sheila, additional, Raveendran, Sreekanth, additional, Sell, Tracey, additional, Sinha, Reetu, additional, Smeeton, Ben T, additional, Smith, Alex C D, additional, Sofos, Stratos, additional, Strong, Ben, additional, Tang, Jasmine Y M, additional, Thacoor, Amitabh, additional, Tucker, Anne, additional, Turkentine, Michele, additional, Cornforth, Mark, additional, Cowdery, Sally, additional, Marasca, Alessandro, additional, Palmer, Helen, additional, Watts, Carole, additional, Watts, Jan, additional, Wiltshire, Rachel, additional, Sing, Quillan Young, additional, Zberea, Diana E, additional, and Mabvuure, Nigel T, additional

Published
2021
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11. Analyzing the efficacy of physician practice acquisition using real option theory

Author

Martin, David G., Ross, Thomas K., and Akinci, Fevzi

Subjects
Derivatives (Financial instruments) -- Management, Decision-making -- Economic aspects, Capital budgets -- Management, Medicine -- Practice, Medicine -- Management, Company business management, Business, Health care industry
Abstract

The real options approach is a decision-making tool to better inform decision makers of capital budgeting choices, and the subsequent impact upon value, in a robust environment. The purpose of [...]

Published
2006

30. Evaluation of Nuclear Research Corporation's ADM-300 Radiation Detection, Indication, and Computation (RADIAC) Instrument

Author

ARMSTRONG LAB BROOKS AFB TX, Armstrong, Dennis R., Hoak, William V., Nixon, Jocelyn, Martin, David G., ARMSTRONG LAB BROOKS AFB TX, Armstrong, Dennis R., Hoak, William V., Nixon, Jocelyn, and Martin, David G.

Abstract

An evaluation of Nuclear Research Corporation's ADM-300 RADIAC survey meter was requested by HQ USAF/XOOTM as a possible replacement for the AN/PDR-27 and AN/PDR-43 survey meters. This evaluation was performed in accordance with criteria specified in ANSI N42.17A-1989 and MIL-STD-810D (1983). Two configurations of the ADM-300 were tested: (1) ADM-300 with beta/gamma detectors along the side, and (2) ADM-300 with beta/gamma detectors along the bottom. The ADM-300 passed most ANSI N42.17A criteria. It has a flat energy response from 252 keV to 1,250 keV, deviates from the true delivered exposure by less than 5% from 1 micron R/hr to 2,000 R/hr, and passes all environmental test conditions when the ANSI N42.17A general criteria of + or - 15% is applied. The angular dependence of the ADM-300 with the beta/gamma detectors along the bottom is less severe than the ADM-300 with the beta/gamma detectors along the side. External probes are available for the ADM-300, and these should be subjected to similar testing prior to procurement.... ADM-300, Angular dependence, Gaussian distribution, Radiation environmental, AN/PDR-27, ANSI N42.17A, MIL-STD-810D, Statistical analysis, AN/PDR-43, Energy dependence, RADIAC.

Published
1992

31. Bioactive compounds from aquatic and terrestrial sources

Author

Rinehart, Kenneth L., Holt, Tom G., Fregeau, Nancy L., Keifer, Paul A., Robert Wilson, George, Thomas, J. Perun, Sakai, Ryuichi, Thompson, Anthony G., Stroh, Justin G., Shield, Lois S., Seigler, David S., Li, Li H., Martin, David G., Grimmelikhuijzen, Cornelis J.P., Gäde, Gerd, Rinehart, Kenneth L., Holt, Tom G., Fregeau, Nancy L., Keifer, Paul A., Robert Wilson, George, Thomas, J. Perun, Sakai, Ryuichi, Thompson, Anthony G., Stroh, Justin G., Shield, Lois S., Seigler, David S., Li, Li H., Martin, David G., Grimmelikhuijzen, Cornelis J.P., and Gäde, Gerd

Abstract

The world of nature provides a never-ending set of fascinating problems for the chemist. Many of the most intriguing problems, however, concern compounds available in only truly minute quantities. One solution is to focus on bioassay-guided separations. In so doing one can isolate compounds with novel structures or unsuspected activities from almost any phylum, including tunicates, sponges, insects, or even the much-studied terrestrial plants, as exemplified in several recent studies in our laboratory involving activities ranging from antiviral and antimicrobial activity to cytotoxicity and immunomodulation Moreover, newer spectroscopic techniques, especially fest atom bombardment mass spectrometry and tandem mass spectrometry, enhance one's ability to study compounds present in minute quantities, including those of importance to the host organism, such as neuropeptides in insects or marine invertebrates.

Published
1990

38. Bioactive Compounds from Aquatic and Terrestrial Sources

Author

Rinehart, Kenneth L., primary, Holt, Tom G., additional, Fregeau, Nancy L., additional, Keifer, Paul A., additional, Wilson, George Robert, additional, Perun, Thomas J., additional, Sakai, Ryuichi, additional, Thompson, Anthony G., additional, Stroh, Justin G., additional, Shield, Lois S., additional, Seigler, David S., additional, Li, Li H., additional, Martin, David G., additional, Grimmelikhuijzen, Cornelis J. P., additional, and Gäde, Gerd, additional

Published
1990
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45. The Future of U.S. Business Education: Some Not-So Random Thoughts.

Author

Martin, David G.

Abstract

The article examines the factors shaping business education in the U.S. at present. According to the author, AACSB International has been aggressive in approving more institutions and has been the first driver in making many changes in business colleges worldwide. It says that AACSB substituted its standards to make its accreditation more appealing to non-U.S. institutions. It also mentions that data from AACSB and GMAC reveals that enrollments in most graduate business programs have been on the decline.

Published
2007

46. The Recovered Civil War Flag of the 33d New Jersey.

Author

Martin, David G.

Subjects
NEW Jersey state history, MILITARY standards, SHERMAN'S March to the Sea, SHERMAN'S March through the Carolinas, SURRENDER (Military), AMERICAN Civil War, 1861-1865
Abstract

The article focuses on the history of the New Jersey 33d Infantry Regiment and their regimental flag during the U.S. Civil War. The regiment was mustered by Colonel George W. Mindil during the summer of 1863, generally from men living in the northeast area of the state. After serving with Major General Oliver O. Howard's Corps in Alabama, they joined General William T. Sherman's march, the siege of Atlanta, Georgia, and then witnessed the surrender of Confederate General Joe Johnston.

Published
2003

47. Assessment Is Hell -- or Not!

Author

Martin, David G.

Abstract

The article discusses the concept of assessment and its strengths and weaknesses. It describes an assessment as a systematic process where a student's success at demonstrating that they posses the requisite knowledge and skills believed to be important is measurement. It points out that assessment is programmatic and courses are assessed because it is convenient. It says that assessment should get the students to perform to high standards.

Published
2012

48. High precision angle calibration for spherical measurement systems

Author

Martin, David G.

Subjects
TK, QC
Abstract

The European Synchrotron Radiation Facility (ESRF) located in Grenoble, France is a joint facility supported and shared by 19 European countries. It operates the most powerful synchrotron radiation source in Europe. Synchrotron radiation sources address many important questions in modern science and technology. They can be compared to “super microscopes”, revealing invaluable information in numerous fields of diverse research such as physics, medicine, biology, geophysics and archaeology. For the ESRF accelerators and beam lines to work correctly, alignment is of critical importance. Alignment tolerances are typically much less than one millimetre and often in the order of several micrometers over the 844 m ESRF storage ring circumference. To help maintain these tolerances, the ESRF has, and continues to develop calibration techniques for high precision spherical measurement system (SMS) instruments. SMSs are a family of instruments comprising automated total stations (theodolites equipped with distance meters), referred to here as robotic total stations (RTSs); and laser trackers (LTs). The ESRF has a modern distance meter calibration bench (DCB) used for the calibration of SMS electronic distance meters. At the limit of distance meter precision, the only way to improve positional uncertainty in the ESRF alignment is to improve the angle measuring capacity of these instruments. To this end, the horizontal circle comparator (HCC) and the vertical circle comparator (VCC) have been developed. Specifically, the HCC and VCC are used to calibrate the horizontal and vertical circle readings of SMS instruments under their natural working conditions. Combined with the DCB, the HCC and VCC provide a full calibration suite for SMS instruments. This thesis presents their development, functionality and in depth uncertainty evaluation. Several unique challenges are addressed in this work. The first is the development and characterization of the linked encoders configuration (LEC). This system, based on two continuously rotating angle encoders, is designed improve performance by eliminating residual encoder errors. The LEC can measure angle displacements with an estimated uncertainty of at least 0.044 arc seconds. Its uncertainty is presently limited by the instrumentation used to evaluate it. Secondly, in depth investigation has lead to the discovery of previously undocumented error-motion effects in ultra-precision angle calibration. Finally, methods for rigorous characterisation and extraction of rotary table error motions and their uncertainty evaluation using techniques not previously discussed in the literature have been developed.

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