Mark Davis - Academia.edu (original) (raw)
Papers by Mark Davis
AHS International Forum 73, May 8, 2017
Advances in Digital Forensics
The use of digital forensic tools by law enforcement agencies has made it difficult for malicious... more The use of digital forensic tools by law enforcement agencies has made it difficult for malicious individuals to hide potentially incriminating evidence. To combat this situation, the hacker community has developed anti-forensic tools that remove or hide electronic evidence for the specific purpose of undermining forensic investigations. This paper examines the latest techniques for hiding data in the popular Ext2 and Ext3 file systems. It also describes techniques for detecting hidden data in the reserved portions of these file systems.
2005 International Conference on Wireless Networks, Communications and Mobile Computing, 2005
The Science of The Total Environment, 2002
The United States (US) Environmental Protection Agency (EPA) estimated that the use of technical ... more The United States (US) Environmental Protection Agency (EPA) estimated that the use of technical grade pentachlorophenol (PCP) between 1970 and 1995 to treat wood was approximately 400,000 metric tons in the US, and that between 4800 and 36,000 g of 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) were incorporated annually in treated wood. The EPA has been unable, however, to estimate the rate of release of polychlorinated dibenzo-p-dioxins and dibenzofurans (CDD/Fs) from treated utility poles into the environment. There is some evidence that CDD/Fs leach from treated poles into the surrounding soils, but these studies do not allow for the calculation of a rate of release from this mechanism. Another possible release mechanism is the volatilization of dioxins into the atmosphere, but there are no data to demonstrate, much less quantify, this release. While not directly measuring the release of dioxins from treated utility poles into the environment, this study was designed to examine the potential for such release. The general approach taken was to collect PCP-treated poles of varying ages, to remove and analyze multiple samples from each pole cross-section, and to compare the spatial distribution of CDD/F congeners among poles of different ages. Evidence of concentration-depth profile changes over time may provide insight into the potential for dioxins to migrate through and then out of PCP-treated utility poles. It was found that the CDD/F concentrations were consistently higher in the outer portions of the poles than the center. This trend tends to be most marked in older poles and for the lower chlorinated congeners. The trend for dioxins to concentrate in the outer portions of the pole over time suggest migration within the poles, and this migration may result in some environmental release. Other possible explanations were also offered.
2007 IEEE 18th International Symposium on Personal, Indoor and Mobile Radio Communications, 2007
Service Science, 2015
Technology continues to affect today’s businesses in general and services in particular. With the... more Technology continues to affect today’s businesses in general and services in particular. With the globalization of business, service organizations have access to many of the same external resources. As a result, services must look internally to how they design their delivery processes to increase the value of their offerings. One element that appears to offer such opportunities is the creation of service inventories in the design of the service delivery process. We define service inventory as any tangible or intangible operand resource that is transformed by the service provider with or without customer input and is stored prior to the customer’s arrival. The goal of service inventories is to facilitate the steps in the service delivery process, thereby creating customer value during the service encounter. Within this context, service inventories can be either physical or digital; we focus primarily on the creation of digital service inventories and how they add value for both the p...
IFIP Advances in Information and Communication Technology, 2006
Digital forensic investigations can be subverted by hostile forensic techniques and tools. This p... more Digital forensic investigations can be subverted by hostile forensic techniques and tools. This paper examines various hostile forensic techniques, including the exploitation of vulnerabilities in standard forensic procedures and denial of service attacks on forensic tools during imaging and analysis. Several techniques for concealing evidence within file systems and external to file systems are highlighted. In addition, strategies for countering hostile forensic techniques and tools are discussed.
Biotechnology for biofuels, 2014
In order to rapidly and efficiently screen potential biofuel feedstock candidates for quintessent... more In order to rapidly and efficiently screen potential biofuel feedstock candidates for quintessential traits, robust high-throughput analytical techniques must be developed and honed. The traditional methods of measuring lignin syringyl/guaiacyl (S/G) ratio can be laborious, involve hazardous reagents, and/or be destructive. Vibrational spectroscopy can furnish high-throughput instrumentation without the limitations of the traditional techniques. Spectral data from mid-infrared, near-infrared, and Raman spectroscopies was combined with S/G ratios, obtained using pyrolysis molecular beam mass spectrometry, from 245 different eucalypt and Acacia trees across 17 species. Iterations of spectral processing allowed the assembly of robust predictive models using partial least squares (PLS). The PLS models were rigorously evaluated using three different randomly generated calibration and validation sets for each spectral processing approach. Root mean standard errors of prediction for valida...
SSRN Electronic Journal, 2012
The utility indifference framework has received a lot of attention, because it is based on a util... more The utility indifference framework has received a lot of attention, because it is based on a utility maximization principle, which is one of the most fundamental principles of economics, for pricing a contingent claim. The price based on utility indifference framework is the maximum or minimum (in some cases, threshold) price for each investor. Therefore, the price is the indicator for the investor to join the market of the contingent claim. Our purpose is to expand the view of utility indifference framework, that is, to deduce the equilibrium price in the utility indifference framework. We attain the result that, under the setting of an exponential utility, the equilibrium price will be uniquely evaluated by minimal entropy martingale measure.
Sociology of Health and Illness, 2006
This paper addresses how London gay men use the internet to meet sexual partners, or for e-dating... more This paper addresses how London gay men use the internet to meet sexual partners, or for e-dating. Based on qualitative interviews conducted face-to-face or via the internet, this research develops an account of how information technologies mediate the negotiation of identity and risk in connection with sexual practice. E-dating itself is a bricolage, or heterogeneous DIY practice of internet-based-communication (IBC). A central aspect of IBC is 'filtering' in and out prospective e-dates based on the images and texts used to depict sexual identities. Interpretations and depictions of personal HIV risk management approaches in IBC are framed by the meanings of different identities, such as the stigma associated with being HIV positive. This paper argues for a sexualities perspective in a theory of network society. Further, HIV prevention in e-dating can potentially be addressed by considering the interplay of the HIV prevention imperatives associated with different HIV serostatus identities. There is a case for encouraging more explicit IBC about risk in e-dating and incorporating the expertise of e-daters in prevention activity. There is also a need to rethink traditional conceptions of risk management in HIV prevention to make space for the risk management bricolage of network society.
Journal of Personality and Social Psychology, 1985
Journal of Personality and Social Psychology, 1994
Journal of Personality and Social Psychology, 1987
Journal of Personality and Social Psychology, 1986
Recent years have seen a burgeoning interest in the psychological state of loneliness, which is c... more Recent years have seen a burgeoning interest in the psychological state of loneliness, which is conceived of as the subjective experience of remoteness and social isolation. Loneliness has come to be recognized as a pervasive phenomenon in contemporary U.
Journal of Personality and Social Psychology, 1985
In light of these findings, a systematic study of loneliness has recently begun. Some of this res... more In light of these findings, a systematic study of loneliness has recently begun. Some of this research has linked feelings of loneliness to the quantity of one's social interaction (Brennan, 1982; Jones, Hansson, & Smith, 1980; Russell et al., 1980), with lonely respondents indicating that they dated less frequently, spent more time alone, and engaged in fewer social activities than nonlonely respondents. Results from other investigations, however, indicate that the quality of social interaction is a more potent influence on feelings of loneliness (Chelune,
JAIDS Journal of Acquired Immune Deficiency Syndromes, 2004
Objective: To compare the characteristics of men who have sex with men (MSM) surveyed online (thr... more Objective: To compare the characteristics of men who have sex with men (MSM) surveyed online (through gay Internet chat rooms and profiles) and offline (in community venues) in London, UK. Methods: In February and March 2002, 879 MSM completed a selfadministered pen-and-paper questionnaire distributed in central London gyms (offline sample). In May and June 2002, 1218 London MSM completed a self-administered questionnaire online, accessed through Internet chat rooms and profiles on gaydar and gay.com. Results: Compared with men surveyed offline, those surveyed online were significantly less likely to only have sex with men (89 vs. 94%), to be in a relationship with a man (44 vs. 52%), or to have been tested for HIV (68 vs. 80%) (P < 0.001). Men recruited online were also younger (mean age, 34 vs. 36 years) and less likely to have had a higher education (67 vs. 79%) (P < 0.001). However, differences between online and offline samples were less pronounced for HIVpositive men and more pronounced for HIV-negative men and those who had never been tested for HIV. Regardless of HIV status, men recruited online were more likely to report high-risk sexual behavior (i.e., unprotected anal intercourse with a partner of unknown or discordant HIV status) than men surveyed offline (32 vs. 22%, P < 0.001). Men recruited online were also significantly more likely to have used the Internet to look for sex (85 vs. 45%, P < 0.001); for HIV-positive and negative men, seeking sex on the Internet was associated with high-risk sexual behavior (P < 0.01). In multivariate analysis, after controlling for confounding factors, being surveyed online was independently associated with high-risk sexual behavior for HIV-negative and never-tested men (HIV-negative men, adjusted odds ratio for online vs. offline samples, 1.73; 95% CI, 1.23, 2.42; P < 0.01; never-tested men adjusted odds ratio 2.45; 95% CI, 1.40, 4.29; P < 0.01). This was not the case for HIV-positive men (adjusted odds ratio for online vs. offline samples, 1.32; 95% CI, 0.69, 2.50; P = 0.4). Conclusion: The Internet offers valuable opportunities for conducting behavioral surveillance among MSM because it reaches some men who may not be easily accessed in the community yet who are at high risk for HIV and sexually transmitted diseases. Comparisons of the social, demographic, and behavioral characteristics of online and offline samples must, however, take into account the confounding effects of HIV status and seeking sex on the Internet.
Energy for Sustainable Development, 2001
The use of solar home systems is widely recommended as a more viable alternative to grid extensio... more The use of solar home systems is widely recommended as a more viable alternative to grid extension in rural areas of developing countries. However, despite a large body of literature on the impacts of grid electrification, very few studies have compared the relative socio-economic impacts of these two technical approaches. This paper reports on such a study conducted in Namibia where the government has promoted both options in its rural electrification programme. It was found that the principal benefit of both forms of electrification lay in access to high-quality lighting as well as the use of television. Despite the supply limitations of the relatively small solar systems in place, it is concluded that, under the circumstances found in Namibia, both technologies provide a similar level of benefit. Given that grid electrification costs are considerably greater than the costs of providing solar home systems, there is merit in encouraging approaches that treat the subsidisation of these two technologies more evenly.
Clinical Science, 2005
In sheep with HF (heart failure), Ucn1 (urocortin 1) decreases total peripheral resistance and le... more In sheep with HF (heart failure), Ucn1 (urocortin 1) decreases total peripheral resistance and left atrial pressure, and increases cardiac output in association with attenuation of vasopressor hormone systems and enhancement of renal function. In a previous study, we demonstrated in the first human studies that infusion of Ucn1 elevates corticotropin (‘ACTH’), cortisol and ANP (atrial natriuretic peptide), and suppresses the hunger-inducing hormone ghrelin in normal subjects. In the present study, we examined the effects of Ucn1 on pituitary, adrenal and cardiovascular systems in the first Ucn1 infusion study in human HF. In human HF, it is proposed that Ucn1 would augment corticotropin and cortisol release, suppress ghrelin and reproduce the cardiorenal effects seen in animals with HF. On day 3 of a controlled metabolic diet, we studied eight male volunteers with stable HF (ejection fraction <40%; New York Heart Association Class II–III) on two occasions, 2 weeks apart, receivin...
Clinica Chimica Acta, 2007
Hemoglobin and amino-terminal pro-brain natriuretic peptide (NT-proBNP) are both independent pred... more Hemoglobin and amino-terminal pro-brain natriuretic peptide (NT-proBNP) are both independent predictors of mortality in patients with chronic HF. Their combined predictive power for mortality in the setting of acute HF is uncertain. In an international prospective cohort design, we evaluated the relationships between hemoglobin, NT-proBNP, and 60-day mortality in 690 patients with acute HF. The median hemoglobin for the entire cohort was 13.0 g/dL (interquartile range 11.6-14.3). The WHO criterion for anemia was met by 44% (n=305). The 60-day mortality rate for anemic patients was 16.4% vs. 8.8% in non-anemic patients (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001). Anemia was an independent predictor of short-term mortality (OR=1.72, 95% CI=1.05-2.80, p=0.03), as was a NT-proBNP concentration &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;5180 pg/mL (OR=2.32, 95% CI=1.36-3.94 p=0.002). Consideration of four risk groups: not anemic/low NT-proBNP (reference group, n=220), anemic/low NT-proBNP (n=152), not anemic/high NT-proBNP (n=165), and anemic/high NT-proBNP (n=153) revealed respective 60-day mortality rates of 5.0% (referent), 9.2% (OR=1.93, 95% CI=0.85-4.36; p=0.12), 13.9% (OR=3.07, 95% CI=1.45-6.50, p=0.003), and 23.5% (OR=5.84, 95% CI=2.87-11.89,…
… and Service Security, 2009. N2S'09. …, 2009
A cross-layer modification to the DSR protocol is presented in this work which is intended to enh... more A cross-layer modification to the DSR protocol is presented in this work which is intended to enhance the global throughput performance of wireless mesh networks. This modification involves the use of an access efficiency factor (which is a measure of the ...
AHS International Forum 73, May 8, 2017
Advances in Digital Forensics
The use of digital forensic tools by law enforcement agencies has made it difficult for malicious... more The use of digital forensic tools by law enforcement agencies has made it difficult for malicious individuals to hide potentially incriminating evidence. To combat this situation, the hacker community has developed anti-forensic tools that remove or hide electronic evidence for the specific purpose of undermining forensic investigations. This paper examines the latest techniques for hiding data in the popular Ext2 and Ext3 file systems. It also describes techniques for detecting hidden data in the reserved portions of these file systems.
2005 International Conference on Wireless Networks, Communications and Mobile Computing, 2005
The Science of The Total Environment, 2002
The United States (US) Environmental Protection Agency (EPA) estimated that the use of technical ... more The United States (US) Environmental Protection Agency (EPA) estimated that the use of technical grade pentachlorophenol (PCP) between 1970 and 1995 to treat wood was approximately 400,000 metric tons in the US, and that between 4800 and 36,000 g of 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) were incorporated annually in treated wood. The EPA has been unable, however, to estimate the rate of release of polychlorinated dibenzo-p-dioxins and dibenzofurans (CDD/Fs) from treated utility poles into the environment. There is some evidence that CDD/Fs leach from treated poles into the surrounding soils, but these studies do not allow for the calculation of a rate of release from this mechanism. Another possible release mechanism is the volatilization of dioxins into the atmosphere, but there are no data to demonstrate, much less quantify, this release. While not directly measuring the release of dioxins from treated utility poles into the environment, this study was designed to examine the potential for such release. The general approach taken was to collect PCP-treated poles of varying ages, to remove and analyze multiple samples from each pole cross-section, and to compare the spatial distribution of CDD/F congeners among poles of different ages. Evidence of concentration-depth profile changes over time may provide insight into the potential for dioxins to migrate through and then out of PCP-treated utility poles. It was found that the CDD/F concentrations were consistently higher in the outer portions of the poles than the center. This trend tends to be most marked in older poles and for the lower chlorinated congeners. The trend for dioxins to concentrate in the outer portions of the pole over time suggest migration within the poles, and this migration may result in some environmental release. Other possible explanations were also offered.
2007 IEEE 18th International Symposium on Personal, Indoor and Mobile Radio Communications, 2007
Service Science, 2015
Technology continues to affect today’s businesses in general and services in particular. With the... more Technology continues to affect today’s businesses in general and services in particular. With the globalization of business, service organizations have access to many of the same external resources. As a result, services must look internally to how they design their delivery processes to increase the value of their offerings. One element that appears to offer such opportunities is the creation of service inventories in the design of the service delivery process. We define service inventory as any tangible or intangible operand resource that is transformed by the service provider with or without customer input and is stored prior to the customer’s arrival. The goal of service inventories is to facilitate the steps in the service delivery process, thereby creating customer value during the service encounter. Within this context, service inventories can be either physical or digital; we focus primarily on the creation of digital service inventories and how they add value for both the p...
IFIP Advances in Information and Communication Technology, 2006
Digital forensic investigations can be subverted by hostile forensic techniques and tools. This p... more Digital forensic investigations can be subverted by hostile forensic techniques and tools. This paper examines various hostile forensic techniques, including the exploitation of vulnerabilities in standard forensic procedures and denial of service attacks on forensic tools during imaging and analysis. Several techniques for concealing evidence within file systems and external to file systems are highlighted. In addition, strategies for countering hostile forensic techniques and tools are discussed.
Biotechnology for biofuels, 2014
In order to rapidly and efficiently screen potential biofuel feedstock candidates for quintessent... more In order to rapidly and efficiently screen potential biofuel feedstock candidates for quintessential traits, robust high-throughput analytical techniques must be developed and honed. The traditional methods of measuring lignin syringyl/guaiacyl (S/G) ratio can be laborious, involve hazardous reagents, and/or be destructive. Vibrational spectroscopy can furnish high-throughput instrumentation without the limitations of the traditional techniques. Spectral data from mid-infrared, near-infrared, and Raman spectroscopies was combined with S/G ratios, obtained using pyrolysis molecular beam mass spectrometry, from 245 different eucalypt and Acacia trees across 17 species. Iterations of spectral processing allowed the assembly of robust predictive models using partial least squares (PLS). The PLS models were rigorously evaluated using three different randomly generated calibration and validation sets for each spectral processing approach. Root mean standard errors of prediction for valida...
SSRN Electronic Journal, 2012
The utility indifference framework has received a lot of attention, because it is based on a util... more The utility indifference framework has received a lot of attention, because it is based on a utility maximization principle, which is one of the most fundamental principles of economics, for pricing a contingent claim. The price based on utility indifference framework is the maximum or minimum (in some cases, threshold) price for each investor. Therefore, the price is the indicator for the investor to join the market of the contingent claim. Our purpose is to expand the view of utility indifference framework, that is, to deduce the equilibrium price in the utility indifference framework. We attain the result that, under the setting of an exponential utility, the equilibrium price will be uniquely evaluated by minimal entropy martingale measure.
Sociology of Health and Illness, 2006
This paper addresses how London gay men use the internet to meet sexual partners, or for e-dating... more This paper addresses how London gay men use the internet to meet sexual partners, or for e-dating. Based on qualitative interviews conducted face-to-face or via the internet, this research develops an account of how information technologies mediate the negotiation of identity and risk in connection with sexual practice. E-dating itself is a bricolage, or heterogeneous DIY practice of internet-based-communication (IBC). A central aspect of IBC is 'filtering' in and out prospective e-dates based on the images and texts used to depict sexual identities. Interpretations and depictions of personal HIV risk management approaches in IBC are framed by the meanings of different identities, such as the stigma associated with being HIV positive. This paper argues for a sexualities perspective in a theory of network society. Further, HIV prevention in e-dating can potentially be addressed by considering the interplay of the HIV prevention imperatives associated with different HIV serostatus identities. There is a case for encouraging more explicit IBC about risk in e-dating and incorporating the expertise of e-daters in prevention activity. There is also a need to rethink traditional conceptions of risk management in HIV prevention to make space for the risk management bricolage of network society.
Journal of Personality and Social Psychology, 1985
Journal of Personality and Social Psychology, 1994
Journal of Personality and Social Psychology, 1987
Journal of Personality and Social Psychology, 1986
Recent years have seen a burgeoning interest in the psychological state of loneliness, which is c... more Recent years have seen a burgeoning interest in the psychological state of loneliness, which is conceived of as the subjective experience of remoteness and social isolation. Loneliness has come to be recognized as a pervasive phenomenon in contemporary U.
Journal of Personality and Social Psychology, 1985
In light of these findings, a systematic study of loneliness has recently begun. Some of this res... more In light of these findings, a systematic study of loneliness has recently begun. Some of this research has linked feelings of loneliness to the quantity of one's social interaction (Brennan, 1982; Jones, Hansson, & Smith, 1980; Russell et al., 1980), with lonely respondents indicating that they dated less frequently, spent more time alone, and engaged in fewer social activities than nonlonely respondents. Results from other investigations, however, indicate that the quality of social interaction is a more potent influence on feelings of loneliness (Chelune,
JAIDS Journal of Acquired Immune Deficiency Syndromes, 2004
Objective: To compare the characteristics of men who have sex with men (MSM) surveyed online (thr... more Objective: To compare the characteristics of men who have sex with men (MSM) surveyed online (through gay Internet chat rooms and profiles) and offline (in community venues) in London, UK. Methods: In February and March 2002, 879 MSM completed a selfadministered pen-and-paper questionnaire distributed in central London gyms (offline sample). In May and June 2002, 1218 London MSM completed a self-administered questionnaire online, accessed through Internet chat rooms and profiles on gaydar and gay.com. Results: Compared with men surveyed offline, those surveyed online were significantly less likely to only have sex with men (89 vs. 94%), to be in a relationship with a man (44 vs. 52%), or to have been tested for HIV (68 vs. 80%) (P < 0.001). Men recruited online were also younger (mean age, 34 vs. 36 years) and less likely to have had a higher education (67 vs. 79%) (P < 0.001). However, differences between online and offline samples were less pronounced for HIVpositive men and more pronounced for HIV-negative men and those who had never been tested for HIV. Regardless of HIV status, men recruited online were more likely to report high-risk sexual behavior (i.e., unprotected anal intercourse with a partner of unknown or discordant HIV status) than men surveyed offline (32 vs. 22%, P < 0.001). Men recruited online were also significantly more likely to have used the Internet to look for sex (85 vs. 45%, P < 0.001); for HIV-positive and negative men, seeking sex on the Internet was associated with high-risk sexual behavior (P < 0.01). In multivariate analysis, after controlling for confounding factors, being surveyed online was independently associated with high-risk sexual behavior for HIV-negative and never-tested men (HIV-negative men, adjusted odds ratio for online vs. offline samples, 1.73; 95% CI, 1.23, 2.42; P < 0.01; never-tested men adjusted odds ratio 2.45; 95% CI, 1.40, 4.29; P < 0.01). This was not the case for HIV-positive men (adjusted odds ratio for online vs. offline samples, 1.32; 95% CI, 0.69, 2.50; P = 0.4). Conclusion: The Internet offers valuable opportunities for conducting behavioral surveillance among MSM because it reaches some men who may not be easily accessed in the community yet who are at high risk for HIV and sexually transmitted diseases. Comparisons of the social, demographic, and behavioral characteristics of online and offline samples must, however, take into account the confounding effects of HIV status and seeking sex on the Internet.
Energy for Sustainable Development, 2001
The use of solar home systems is widely recommended as a more viable alternative to grid extensio... more The use of solar home systems is widely recommended as a more viable alternative to grid extension in rural areas of developing countries. However, despite a large body of literature on the impacts of grid electrification, very few studies have compared the relative socio-economic impacts of these two technical approaches. This paper reports on such a study conducted in Namibia where the government has promoted both options in its rural electrification programme. It was found that the principal benefit of both forms of electrification lay in access to high-quality lighting as well as the use of television. Despite the supply limitations of the relatively small solar systems in place, it is concluded that, under the circumstances found in Namibia, both technologies provide a similar level of benefit. Given that grid electrification costs are considerably greater than the costs of providing solar home systems, there is merit in encouraging approaches that treat the subsidisation of these two technologies more evenly.
Clinical Science, 2005
In sheep with HF (heart failure), Ucn1 (urocortin 1) decreases total peripheral resistance and le... more In sheep with HF (heart failure), Ucn1 (urocortin 1) decreases total peripheral resistance and left atrial pressure, and increases cardiac output in association with attenuation of vasopressor hormone systems and enhancement of renal function. In a previous study, we demonstrated in the first human studies that infusion of Ucn1 elevates corticotropin (‘ACTH’), cortisol and ANP (atrial natriuretic peptide), and suppresses the hunger-inducing hormone ghrelin in normal subjects. In the present study, we examined the effects of Ucn1 on pituitary, adrenal and cardiovascular systems in the first Ucn1 infusion study in human HF. In human HF, it is proposed that Ucn1 would augment corticotropin and cortisol release, suppress ghrelin and reproduce the cardiorenal effects seen in animals with HF. On day 3 of a controlled metabolic diet, we studied eight male volunteers with stable HF (ejection fraction <40%; New York Heart Association Class II–III) on two occasions, 2 weeks apart, receivin...
Clinica Chimica Acta, 2007
Hemoglobin and amino-terminal pro-brain natriuretic peptide (NT-proBNP) are both independent pred... more Hemoglobin and amino-terminal pro-brain natriuretic peptide (NT-proBNP) are both independent predictors of mortality in patients with chronic HF. Their combined predictive power for mortality in the setting of acute HF is uncertain. In an international prospective cohort design, we evaluated the relationships between hemoglobin, NT-proBNP, and 60-day mortality in 690 patients with acute HF. The median hemoglobin for the entire cohort was 13.0 g/dL (interquartile range 11.6-14.3). The WHO criterion for anemia was met by 44% (n=305). The 60-day mortality rate for anemic patients was 16.4% vs. 8.8% in non-anemic patients (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001). Anemia was an independent predictor of short-term mortality (OR=1.72, 95% CI=1.05-2.80, p=0.03), as was a NT-proBNP concentration &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;5180 pg/mL (OR=2.32, 95% CI=1.36-3.94 p=0.002). Consideration of four risk groups: not anemic/low NT-proBNP (reference group, n=220), anemic/low NT-proBNP (n=152), not anemic/high NT-proBNP (n=165), and anemic/high NT-proBNP (n=153) revealed respective 60-day mortality rates of 5.0% (referent), 9.2% (OR=1.93, 95% CI=0.85-4.36; p=0.12), 13.9% (OR=3.07, 95% CI=1.45-6.50, p=0.003), and 23.5% (OR=5.84, 95% CI=2.87-11.89,…
… and Service Security, 2009. N2S'09. …, 2009
A cross-layer modification to the DSR protocol is presented in this work which is intended to enh... more A cross-layer modification to the DSR protocol is presented in this work which is intended to enhance the global throughput performance of wireless mesh networks. This modification involves the use of an access efficiency factor (which is a measure of the ...