A central problem in the study of human mobility is that of migration systems. Typically, migrati... more A central problem in the study of human mobility is that of migration systems. Typically, migration systems are defined as a set of relatively stable movements of people between two or more locations over time. While these emergent systems are expected to vary over time, they ideally contain a stable underlying structure that could be discovered empirically. There have been some notable attempts to formally or informally define migration systems, however they have been limited by being hard to operationalize, and by defining migration systems in ways that ignore origin/destination aspects and/or fail to account for migration dynamics. In this work we propose a novel method, spatio-temporal (ST) tensor co-clustering, stemming from signal processing and machine learning theory. To demonstrate its effectiveness for describing stable migration systems we focus on domestic migration between counties in the US from 1990-2018. Relevant data for this period has been made available through t...
Decellularized tissues are biocompatible materials that engraft well, but the age of their source... more Decellularized tissues are biocompatible materials that engraft well, but the age of their source has not been explored for clinical translation. Advanced glycation end products (AGEs) are chemical cross-links that accrue on skeletal muscle collagen in old age, stiffening the matrix and increasing inflammation. Whether decellularized biomaterials derived from aged muscle would suffer from increased AGE collagen cross-links is unknown. We characterized gastrocnemii of 1-, 2-, and 20-month-old C57BL/6J mice before and after decellularization to determine age-dependent changes to collagen stiffness and AGE cross-linking. Total and soluble collagen was measured to assess if age-dependent increases in collagen and cross-linking persisted in decellularized muscle matrix (DMM). Stiffness of aged DMM was determined using atomic force microscopy. AGE levels and the effect of an AGE cross-link breaker, ALT-711, were tested in DMM samples. Our results show that age-dependent increases in colla...
PurposeIn this paper, the authors examine the association between conditional conservatism and de... more PurposeIn this paper, the authors examine the association between conditional conservatism and deviations of the first digits of financial statement items from what are expected by Benford's Law.Design/methodology/approachThis research uses data of companies listed on the London Stock Exchange. The authors measure deviations of first digits from Benford's Law following Amiram et al. (2015) and firm-year conditional conservatism following previous studies (Basu, 1997; Khan and Watts, 2009; García Lara et al., 2016). The authors use multiple regressions to provide evidence for their hypothesis.FindingsThe results show that conditional conservatism is positively associated with deviations from Benford's Law. The findings are robust across different measures of deviations and conditional conservatism. Also, the authors find that the relationship between deviations from Benford's Law and conditional conservatism is more pronounced for firms with debt issuance, and for lev...
Context: Suicide risk assessment in the emergency department is a challenging task for psychiatri... more Context: Suicide risk assessment in the emergency department is a challenging task for psychiatrists and is further complicated when patients are admitted involuntarily. Objective: To evaluate the quality of suicide risk assessments in the psychiatric emergency setting by reviewing physician documentation of process indicators. Methods: A retrospective review of medical records for patients who were admitted involuntarily to the Kern Medical Center Psychiatric Emergency Service in Bakersfield, Calif. All patients were deemed a “danger to self” as defined by California Law and were admitted for evaluation in June 2006. Medical records were reviewed for 19 process indicators, which were identified from risk factors and treatment guidelines described in the literature. Documentation that a process indicator was not met by a patient was included in the data. Patients were then separated into two study groups: those who were admitted to the inpatient psychiatric unit, and those who were ...
Farm productivity is essential for meeting the growing demand for food that is fueled by rapid po... more Farm productivity is essential for meeting the growing demand for food that is fueled by rapid population growth around the world. Farming practices can obtain the greatest optimization and profitability through “smart agriculture” which adapts farming techniques to specific conditions via enabling technologies that are often based on an Internet of Things (IoT). This paper presents a case study of an IoT innovation in an unexpected location – a rural farm in Vietnam. A practical, low-cost, and environmental friendly system was developed that help farmers manage their crops with more precision in the first IoT application for the Vietnamese agriculture industry. The pilot implementation were promising and farmer feedback was positive. After some modifications, the system has been widely deployed in different provinces in Vietnam. We believe that the system would be able to help millions of farmers to get on the IoT train and that adopting IoT to initiate smart agriculture in Vietnam...
In this community review report, we discuss applications and techniques for fast machine learning... more In this community review report, we discuss applications and techniques for fast machine learning (ML) in science -- the concept of integrating power ML methods into the real-time experimental data processing loop to accelerate scientific discovery. The material for the report builds on two workshops held by the Fast ML for Science community and covers three main areas: applications for fast ML across a number of scientific domains; techniques for training and implementing performant and resource-efficient ML algorithms; and computing architectures, platforms, and technologies for deploying these algorithms. We also present overlapping challenges across the multiple scientific domains where common solutions can be found. This community report is intended to give plenty of examples and inspiration for scientific discovery through integrated and accelerated ML solutions. This is followed by a high-level overview and organization of technical advances, including an abundance of pointer...
This thesis aims to investigate earnings quality, by employing recent methodologies. The thesis h... more This thesis aims to investigate earnings quality, by employing recent methodologies. The thesis has three empirical chapters. The first empirical chapter is about the profile of chief executive officers (CEO) and earnings quality. Based on previous studies, I introduce a measure of CEO profile, denoted PSCORE, which aggregates nine personal characteristics of CEOs. Data for the construction of the PSCORE are publicly available on the CEOs’ curriculum vitae and firms’ financial statements. Following previous studies, I measure earnings quality in different ways: abnormal accruals (Jones, 1991; Dechow, Sloan, and Sweeney, 1995; Peasnell, Pope, and Young, 2000b); abnormal cash flows, abnormal production costs, and abnormal discretionary expenditures (Roychowdhury, 2006); and deviations of the first digits of figures reported in financial statements from what are expected by Benford’s Law (Amiram, Bozanic, and Rouen, 2015). Using a sample of UK listed companies for 2005-2012, I find pos...
Using a customer-supplier matched sample of US-listed firms from 1980 to 2016, we study the corpo... more Using a customer-supplier matched sample of US-listed firms from 1980 to 2016, we study the corporate cash-holding relationship between suppliers and their major customers. The key findings suggest that the cash-holding levels of suppliers are positively affected by those of their major customers, consistent with the liquidity argument. The effects are more pronounced when the major customers are in more favourable financial conditions and when they are considered more important to their suppliers. Our results are robust to various endogeneity problems and additional tests. Taken together, these results bring forth an important corporate cash-holding link within the supply chain.
Typhoidal and non-typhoidal Salmonelleae (NTS) cause typhoid fever and gastroenteritis, respectiv... more Typhoidal and non-typhoidal Salmonelleae (NTS) cause typhoid fever and gastroenteritis, respectively, in humans. Salmonella typhoid toxin contributes to typhoid disease progression and chronic infection, but little is known about the role of its NTS ortholog. We found that typhoid toxin and its NTS ortholog induce different clinical presentations. The PltB subunit of each toxin exhibits different glycan-binding preferences that correlate with glycan expression profiles of host cells targeted by each bacterium at the primary infection or intoxication sites. Through co-crystal structures of PltB subunits bound to specific glycan receptor moieties, we show that they induce markedly different glycan-binding preferences and virulence outcomes. Furthermore, immunization with the NTS S. Javiana or its toxin offers cross-reactive protection against lethal-dose typhoid toxin challenge. Cumulatively, these results offer insights into the evolution of host adaptations in Salmonella AB toxins, their cell and tissue tropisms, and the design for improved typhoid vaccines and therapeutics.
Background Laparoscopic single-port surgery has widely been introduced for the treatment of vario... more Background Laparoscopic single-port surgery has widely been introduced for the treatment of various abdominal conditions. But controversies still exist regarding its potential advantages and risks, especially for emergency surgery. The aim of this study was to evaluate the results of a single-port laparoscopic repair using straight laparoscopic instruments for the treatment of perforated duodenal ulcers. Methods A prospective consecutive case series was conducted including all patients with a perforated duodenal ulcer who underwent a laparoscopic single-port repair at a single institution from January 2012 to June 2018. The operation was performed through a single port using conventional straight laparoscopic instruments and intra-corporeal knot tying techniques. Results Out of 75 patients, simple closure of the perforation without omental patch was accomplished in 96% of cases. Conversion to an open operation was required in one patient (1.3%) due to a posterior duodenal perforation, and additional trocar placement was needed in another patient (1.3%). The mean incision length was 2.0 ± 0.2 cm. The mean operation time was 63.0 ± 26.6 min. Meantime a nasogastric tube remained in place was 2.9 ± 0.8 days. Mean duration of analgesic use was 2.8 ± 0.8 days. The rate of postoperative complications was 2.7%, including two patients with wound infections. There were no instances of intestinal leak or abscess. The postoperative hospital stay was 5.7 ± 1.2 days. Conclusion Laparoscopic single-port repair using conventional straight laparoscopic instruments with intra-corporeal knot tying technique was safe and feasible for patients with perforated duodenal ulcers with low risk factors. This method offers results comparable to those expected with the standard multiport laparoscopic approach with the addition of improved cosmetic outcomes.
In this work, the green synthesis of silver-silver chloride nanoparticles (Ag@AgClNPs) has been u... more In this work, the green synthesis of silver-silver chloride nanoparticles (Ag@AgClNPs) has been used the plant leaf extract of Chromolaena odorata (C. odorata) as a reducing and capping agent. The effects of parameters on the formation of Ag@AgCl nanoparticles (Ag@AgClNPs such as the ratio of C. odorata raw material/water, the extraction temperature, the extraction duration, and the volume ratios of AgNO3 solution and C. odorata extract have been studied. The obtained Ag@AgClNPs sample was characterized by ultraviolet visible spectroscopy, X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy. UV–visible absorption studies revealed surface plasmon resonance peak around 420‒450 nm, confirming the presence of Ag@AgClNPs. The average particle size was approximately 15.2 nm. The antibacterial activity of Ag@AgClNPs was carried out by the agar well diffusion method and the determination of the minimum inhibitory concentration that showed high toxicity against the gram-negative bacteria (Escherichia coli, Salmonella typhi, and Pseudomonas aeruginosa) and the gram-positive bacteria (Bacillus cereus and Staphylococcus aureus).
A central problem in the study of human mobility is that of migration systems. Typically, migrati... more A central problem in the study of human mobility is that of migration systems. Typically, migration systems are defined as a set of relatively stable movements of people between two or more locations over time. While these emergent systems are expected to vary over time, they ideally contain a stable underlying structure that could be discovered empirically. There have been some notable attempts to formally or informally define migration systems, however they have been limited by being hard to operationalize, and by defining migration systems in ways that ignore origin/destination aspects and/or fail to account for migration dynamics. In this work we propose a novel method, spatio-temporal (ST) tensor co-clustering, stemming from signal processing and machine learning theory. To demonstrate its effectiveness for describing stable migration systems we focus on domestic migration between counties in the US from 1990-2018. Relevant data for this period has been made available through t...
Decellularized tissues are biocompatible materials that engraft well, but the age of their source... more Decellularized tissues are biocompatible materials that engraft well, but the age of their source has not been explored for clinical translation. Advanced glycation end products (AGEs) are chemical cross-links that accrue on skeletal muscle collagen in old age, stiffening the matrix and increasing inflammation. Whether decellularized biomaterials derived from aged muscle would suffer from increased AGE collagen cross-links is unknown. We characterized gastrocnemii of 1-, 2-, and 20-month-old C57BL/6J mice before and after decellularization to determine age-dependent changes to collagen stiffness and AGE cross-linking. Total and soluble collagen was measured to assess if age-dependent increases in collagen and cross-linking persisted in decellularized muscle matrix (DMM). Stiffness of aged DMM was determined using atomic force microscopy. AGE levels and the effect of an AGE cross-link breaker, ALT-711, were tested in DMM samples. Our results show that age-dependent increases in colla...
PurposeIn this paper, the authors examine the association between conditional conservatism and de... more PurposeIn this paper, the authors examine the association between conditional conservatism and deviations of the first digits of financial statement items from what are expected by Benford's Law.Design/methodology/approachThis research uses data of companies listed on the London Stock Exchange. The authors measure deviations of first digits from Benford's Law following Amiram et al. (2015) and firm-year conditional conservatism following previous studies (Basu, 1997; Khan and Watts, 2009; García Lara et al., 2016). The authors use multiple regressions to provide evidence for their hypothesis.FindingsThe results show that conditional conservatism is positively associated with deviations from Benford's Law. The findings are robust across different measures of deviations and conditional conservatism. Also, the authors find that the relationship between deviations from Benford's Law and conditional conservatism is more pronounced for firms with debt issuance, and for lev...
Context: Suicide risk assessment in the emergency department is a challenging task for psychiatri... more Context: Suicide risk assessment in the emergency department is a challenging task for psychiatrists and is further complicated when patients are admitted involuntarily. Objective: To evaluate the quality of suicide risk assessments in the psychiatric emergency setting by reviewing physician documentation of process indicators. Methods: A retrospective review of medical records for patients who were admitted involuntarily to the Kern Medical Center Psychiatric Emergency Service in Bakersfield, Calif. All patients were deemed a “danger to self” as defined by California Law and were admitted for evaluation in June 2006. Medical records were reviewed for 19 process indicators, which were identified from risk factors and treatment guidelines described in the literature. Documentation that a process indicator was not met by a patient was included in the data. Patients were then separated into two study groups: those who were admitted to the inpatient psychiatric unit, and those who were ...
Farm productivity is essential for meeting the growing demand for food that is fueled by rapid po... more Farm productivity is essential for meeting the growing demand for food that is fueled by rapid population growth around the world. Farming practices can obtain the greatest optimization and profitability through “smart agriculture” which adapts farming techniques to specific conditions via enabling technologies that are often based on an Internet of Things (IoT). This paper presents a case study of an IoT innovation in an unexpected location – a rural farm in Vietnam. A practical, low-cost, and environmental friendly system was developed that help farmers manage their crops with more precision in the first IoT application for the Vietnamese agriculture industry. The pilot implementation were promising and farmer feedback was positive. After some modifications, the system has been widely deployed in different provinces in Vietnam. We believe that the system would be able to help millions of farmers to get on the IoT train and that adopting IoT to initiate smart agriculture in Vietnam...
In this community review report, we discuss applications and techniques for fast machine learning... more In this community review report, we discuss applications and techniques for fast machine learning (ML) in science -- the concept of integrating power ML methods into the real-time experimental data processing loop to accelerate scientific discovery. The material for the report builds on two workshops held by the Fast ML for Science community and covers three main areas: applications for fast ML across a number of scientific domains; techniques for training and implementing performant and resource-efficient ML algorithms; and computing architectures, platforms, and technologies for deploying these algorithms. We also present overlapping challenges across the multiple scientific domains where common solutions can be found. This community report is intended to give plenty of examples and inspiration for scientific discovery through integrated and accelerated ML solutions. This is followed by a high-level overview and organization of technical advances, including an abundance of pointer...
This thesis aims to investigate earnings quality, by employing recent methodologies. The thesis h... more This thesis aims to investigate earnings quality, by employing recent methodologies. The thesis has three empirical chapters. The first empirical chapter is about the profile of chief executive officers (CEO) and earnings quality. Based on previous studies, I introduce a measure of CEO profile, denoted PSCORE, which aggregates nine personal characteristics of CEOs. Data for the construction of the PSCORE are publicly available on the CEOs’ curriculum vitae and firms’ financial statements. Following previous studies, I measure earnings quality in different ways: abnormal accruals (Jones, 1991; Dechow, Sloan, and Sweeney, 1995; Peasnell, Pope, and Young, 2000b); abnormal cash flows, abnormal production costs, and abnormal discretionary expenditures (Roychowdhury, 2006); and deviations of the first digits of figures reported in financial statements from what are expected by Benford’s Law (Amiram, Bozanic, and Rouen, 2015). Using a sample of UK listed companies for 2005-2012, I find pos...
Using a customer-supplier matched sample of US-listed firms from 1980 to 2016, we study the corpo... more Using a customer-supplier matched sample of US-listed firms from 1980 to 2016, we study the corporate cash-holding relationship between suppliers and their major customers. The key findings suggest that the cash-holding levels of suppliers are positively affected by those of their major customers, consistent with the liquidity argument. The effects are more pronounced when the major customers are in more favourable financial conditions and when they are considered more important to their suppliers. Our results are robust to various endogeneity problems and additional tests. Taken together, these results bring forth an important corporate cash-holding link within the supply chain.
Typhoidal and non-typhoidal Salmonelleae (NTS) cause typhoid fever and gastroenteritis, respectiv... more Typhoidal and non-typhoidal Salmonelleae (NTS) cause typhoid fever and gastroenteritis, respectively, in humans. Salmonella typhoid toxin contributes to typhoid disease progression and chronic infection, but little is known about the role of its NTS ortholog. We found that typhoid toxin and its NTS ortholog induce different clinical presentations. The PltB subunit of each toxin exhibits different glycan-binding preferences that correlate with glycan expression profiles of host cells targeted by each bacterium at the primary infection or intoxication sites. Through co-crystal structures of PltB subunits bound to specific glycan receptor moieties, we show that they induce markedly different glycan-binding preferences and virulence outcomes. Furthermore, immunization with the NTS S. Javiana or its toxin offers cross-reactive protection against lethal-dose typhoid toxin challenge. Cumulatively, these results offer insights into the evolution of host adaptations in Salmonella AB toxins, their cell and tissue tropisms, and the design for improved typhoid vaccines and therapeutics.
Background Laparoscopic single-port surgery has widely been introduced for the treatment of vario... more Background Laparoscopic single-port surgery has widely been introduced for the treatment of various abdominal conditions. But controversies still exist regarding its potential advantages and risks, especially for emergency surgery. The aim of this study was to evaluate the results of a single-port laparoscopic repair using straight laparoscopic instruments for the treatment of perforated duodenal ulcers. Methods A prospective consecutive case series was conducted including all patients with a perforated duodenal ulcer who underwent a laparoscopic single-port repair at a single institution from January 2012 to June 2018. The operation was performed through a single port using conventional straight laparoscopic instruments and intra-corporeal knot tying techniques. Results Out of 75 patients, simple closure of the perforation without omental patch was accomplished in 96% of cases. Conversion to an open operation was required in one patient (1.3%) due to a posterior duodenal perforation, and additional trocar placement was needed in another patient (1.3%). The mean incision length was 2.0 ± 0.2 cm. The mean operation time was 63.0 ± 26.6 min. Meantime a nasogastric tube remained in place was 2.9 ± 0.8 days. Mean duration of analgesic use was 2.8 ± 0.8 days. The rate of postoperative complications was 2.7%, including two patients with wound infections. There were no instances of intestinal leak or abscess. The postoperative hospital stay was 5.7 ± 1.2 days. Conclusion Laparoscopic single-port repair using conventional straight laparoscopic instruments with intra-corporeal knot tying technique was safe and feasible for patients with perforated duodenal ulcers with low risk factors. This method offers results comparable to those expected with the standard multiport laparoscopic approach with the addition of improved cosmetic outcomes.
In this work, the green synthesis of silver-silver chloride nanoparticles (Ag@AgClNPs) has been u... more In this work, the green synthesis of silver-silver chloride nanoparticles (Ag@AgClNPs) has been used the plant leaf extract of Chromolaena odorata (C. odorata) as a reducing and capping agent. The effects of parameters on the formation of Ag@AgCl nanoparticles (Ag@AgClNPs such as the ratio of C. odorata raw material/water, the extraction temperature, the extraction duration, and the volume ratios of AgNO3 solution and C. odorata extract have been studied. The obtained Ag@AgClNPs sample was characterized by ultraviolet visible spectroscopy, X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy. UV–visible absorption studies revealed surface plasmon resonance peak around 420‒450 nm, confirming the presence of Ag@AgClNPs. The average particle size was approximately 15.2 nm. The antibacterial activity of Ag@AgClNPs was carried out by the agar well diffusion method and the determination of the minimum inhibitory concentration that showed high toxicity against the gram-negative bacteria (Escherichia coli, Salmonella typhi, and Pseudomonas aeruginosa) and the gram-positive bacteria (Bacillus cereus and Staphylococcus aureus).
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