Characterizing oil and gas wells with fugitive gas migration through Bayesian multilevel logistic regression.

Oil and gas wells are engineered with barriers to prevent fluid movement along the wellbore. If the integrity of one or more of these barriers fails, it may result in subsurface leakage of natural gas outside the well casing, a process termed fugitive gas migration (GM). Knowledge of the occurrence and causes of GM is essential for effective management of associated potential risks. In the province of British Columbia, Canada (BC), oil and gas producers are required to report well drilling, completion, production, and abandonment records for all oil and gas wells to the provincial regulator. This well data provides a unique opportunity to identify well characteristics with higher likelihoods for GM to develop. Here we employ Bayesian multilevel logistic regression to understand the associations between various well attributes and reported occurrences of GM in 0.6% of the 25,000 oil and gas wells in BC. Our results indicate that there is no association between the occurrence of GM and hydraulic fracturing. Overall, there appears to be no well construction or operation attribute in the study database that is conclusively associated with GM. Wells with GM more frequently exhibit indicators of well integrity loss (i.e., surface casing vent flow, remedial treatments, and blowouts) and geographic location appears to be important. We ascribe the spatial clustering of GM cases to the local geologic environment, and we speculate that there are links between particular intermediate gas-bearing formations and GM occurrence in the Fort Nelson Plains Area. The results of this study suggest that oil and gas wells in high GM occurrence areas and those showing any attribute associated with integrity failure (e.g., surface casing vent flow) should be prioritized for monitoring to improve the detection of GM.

Levels of resilience, anxiety and depression in nurses working in respiratory clinical areas during the COVID pandemic.

BACKGROUND: The delivery of healthcare during the COVID pandemic has had a significant impact on front line staff. Nurses who work with respiratory patients have been at the forefront of the pandemic response. Lessons can be learnt from these nurses' experiences in order to support these nurses during the existing pandemic and retain and mobilise this skilled workforce for future pandemics. METHODS: This study explores UK nurses' experiences of working in a respiratory environment during the COVID-19 pandemic. An e-survey was distributed via professional respiratory societies; the survey included a resilience scale, the GAD7 (anxiety) and the PHQ9 (depression) tools. Demographic data was collected on age, gender, ethnicity, nursing experience and background, clinical role in the pandemic, and home-life and work balance. RESULTS: Two hundred and fifty-five responses were received for the survey, predominately women (89%, 226/255), aged over 35 (79%, 202/255). Nearly 21% (40/191) experiencing moderate to severe or severe symptoms of anxiety. Similar levels are seen for depression (17.2%, 31/181). 18.9% (34/180) had a low or very low resilience score. Regression analysis showed that for both depression and anxiety variables, age and years of qualification provided the best model fit. Younger nurses with less experience have higher levels of anxiety and depression and had lower resilience. CONCLUSION: This cohort experienced significant levels of anxiety and depression, with moderate to high levels of resilience. Support mechanisms and interventions need to be put in place to support all nurses during pandemic outbreaks, particularly younger or less experienced staff.

Effects of chronic prenatal MK-801 treatment on object recognition, cognitive flexibility, and drug-induced locomotor activity in juvenile and adult rat offspring.

BACKGROUND: Patients with schizophrenia display impaired cognitive functioning and increased sensitivity to psychomimetic drugs. The neurodevelopmental hypothesis of schizophrenia posits that disruption of the developing brain predisposes neural networks to lasting structural and functional abnormalities resulting in the emergence of such symptoms in adulthood. Given the critical role of the glutamatergic system in early brain development, we investigated whether chronic prenatal exposure to the glutamate NMDA receptor antagonist, MK-801, induces schizophrenia-like behavioural and neurochemical changes in juvenile and adult rats. METHODS: Pregnant Long-Evans rats were administered saline or MK-801 (0.1mg/kg; s.c.) at gestation day 7-19. Object recognition memory and cognitive flexibility were assessed in the male offspring using a novel object preference task and a maze-based set-shifting procedure, respectively. Locomotor-activating effects of acute amphetamine and MK-801 were also assessed. RESULTS: Adult, but not juvenile, prenatally MK-801-treated rats failed to show novel object preference after a 90min delay, suggesting that object recognition memory may have been impaired. In addition, the set-shifting task revealed impaired acquisition of a new rule in adult prenatally MK-801-treated rats compared to controls. This deficit appeared to be driven by regression to the previously learned behaviour. There were no significant differences in drug-induced locomotor activity in juvenile offspring or in adult offspring following acute amphetamine challenges. Unexpectedly, MK-801-induced locomotor activity in adult prenatally MK-801-treated rats was lower compared to controls. CONCLUSIONS: Glutamate transmission dysfunction during early development may modify behavioural parameters in adulthood, though these parameters do not appear to model deficits observed in schizophrenia.

European Network of Forensic Science Institutes (ENFSI): Evaluation of new commercial STR multiplexes that include the European Standard Set (ESS) of markers.

To support and to underpin the European initiative to increase the European set of standard markers (ESS), by the addition of five new loci, a collaborative project was organised by the European Network of Forensic Science Institutes (ENFSI) DNA working group in order to assess the new multiplex kits available. We have prepared allele frequency databases from 26 EU populations. Concordance studies were carried out to verify that genotyping results were consistent between kits. Population genetics studies were conducted and it was estimated that F(ST)<0.001. The results showed that the kits were comparable to each other in terms of performance and major discrepancy issues were highlighted. We provide details of allele frequencies for each of the populations analysed per laboratory.

Myoglobin production in emperor penguins.

Increased oxygen storage is essential to the diving capacities of marine mammals and seabirds. However, the molecular mechanisms underlying this adaptation are unknown. Myoglobin (Mb) and Mb mRNA concentrations were analyzed in emperor penguin (Aptenodytes forsteri) adults and chicks with spectrophotometric and RNase protection assays to evaluate production of their large Mb-bound O(2) stores. Mean pectoral Mb concentration and Mb mRNA content increased throughout the pre-fledging period and were 15-fold and 3-fold greater, respectively, in adults than in 3.5 month old chicks. Mean Mb concentration in 5.9 month old juveniles was 2.7+/-0.4 g 100 g(-1) muscle (44% that of wild adults), and in adults that had been captive all their lives it was 3.7+/-0.1 g 100 g(-1) muscle. The Mb and Mb mRNA data are consistent with regulation of Mb production at the level of transcription as in other animals. Significant Mb and Mb mRNA production occurred in chicks and young juveniles even without any diving activity. The further increase in adult Mb concentrations appears to require the exercise/hypoxia of diving because Mb concentration in captive, non-diving adults only reached 60% of that of wild adults. The much greater relative increase in Mb concentration than in Mb mRNA content between young chicks and adults suggests that there is not a simple 1:1 relationship between Mb mRNA content and Mb concentration. Nutritional limitation in young chicks and post-transcriptional regulation of Mb concentration may also be involved.

A concept for ab initio prediction of cis-regulatory modules.

An important concern in the attempt of understanding the functional code of eukaryotic genes is to elucidate the control structures for regulating gene activation and suppression. One objective in the attempt to understand mechanisms of gene regulation is the elucidation of the regulatory network structure. A preliminary step of a detailed network analysis is identifying the transcription factor binding sites of a regulatory network. Known as cis-regulatory module (CRM), it is understood as part of the genome that comprises a set of short length binding sites. Gene regulatory systems are known to be quite stable during evolution, as compared to relatively frequent replication processes of genes and mutations of the coding sequences. This conservation property of regulatory code can advantageously be used for identifying cis-regulatory modules of potentially co-regulated genes. As the degree of similarity is expected to depend on the phylogenetic distance of homologs or orthologs, we favor an approach that is based on a comparison paradigm. The paper introduces a novel concept for measuring the similarity ofcis-regulatory modules which can then be used in an algorithm for comparing regulatory regions. The proposed algorithm searches for pairs of similar modules, and a prototype implementation is applied to human and mouse liver sequences. The results are compared to that of random sequences, and it is shown that a clear decision about co-regulation is possible at this level.

A systematic review on the efficacy of cytoreductive surgery combined with perioperative intraperitoneal chemotherapy for diffuse malignancy peritoneal mesothelioma.

BACKGROUND: In the past, diffuse malignant peritoneal mesothelioma (DMPM) was regarded as a preterminal condition. The length of survival was dependent upon the aggressive versus indolent biologic behavior of the neoplasm. The overall median survival was approximately 1 year after systemic chemotherapy. Cytoreductive surgery (CRS) combined with perioperative intraperitoneal chemotherapy (PIC) has been used as a treatment alternative, but the efficacy of this combined treatment remains to be established. PATIENTS AND METHODS: Searches for relevant studies published in peer-reviewed medical journals on CRS and PIC for DMPM before May 2006 were carried out on six databases. The reference lists of all retrieved articles were reviewed for further identification of potentially relevant studies. Expert academic surgeons in Washington, DC, USA were asked whether they knew about any important unpublished data. Two investigators independently evaluated each study according to predefined criteria. The quality of each study was assessed. Clinical effectiveness was synthesized through a narrative review with full tabulation of results of all included studies. RESULTS: Seven prospective observational studies from six tertiary institutions were available, allowing 240 DMPM patients for assessment. The median survival ranged from 34-92 months. The 1-, 3- and 5-year survival varied from 60% to 88%, 43% to 65% and 29% to 59%, respectively. The perioperative morbidity varied from 25% to 40% and mortality ranged from 0% to 8%. CONCLUSIONS: This systematic review evaluated the current evidence for CRS and PIC for DMPM. Seven observational studies were available for assessment, which demonstrated an improved overall survival, as compared to historical controls, using systemic chemotherapy and palliative surgery.

Imaging the spatial distribution of transgene expression in the lungs with positron emission tomography.

This study was designed to evaluate the utility of positron emission tomography (PET) to quantify the magnitude and spatial distribution of transgene expression after different methods of adenoviral vector delivery (with surfactant- and saline-based vehicles) within rat lungs. In all, 17 animals (eight in the surfactant group, nine in the saline group) were studied 3 days after intratracheal administration of a replication-incompetent adenovirus encoding a mutant Herpes simplex virus-1 thymidine kinase (mHSV1-TK)-enhanced green fluorescent protein fusion gene driven by a Cytomegalovirus promoter (Ad-CMV-mNLS-HSV1sr39tk-egfp). PET images were obtained 1 h after i.v. administration of 9-(4-[(18)F]-fluoro-3-hydroxymethylbutyl)guanine ([(18)F]-FHBG), an imaging substrate for mHSV1-TK. Overall, the average lung concentration of [(18)F]-FHBG was significantly greater in the surfactant group than in the saline group (0.24+/-0.06 versus 0.17+/-0.03% injected dose/ml lung, P< or =0.05). Lung [(18)F]-FHBG distribution was more peripheral and more homogeneous in the surfactant group than in the saline group (mean coefficient of variation=31+/-4 versus 36+/-3%, respectively, P< or =0.05). Regions of increased tracer concentration in the surfactant group compared to the saline group were evenly distributed throughout the lungs. We conclude that PET imaging provides useful and meaningful information about the effectiveness of different gene transfer delivery strategies within the lungs, and that surfactant-based vehicles may be a superior strategy for pulmonary gene transfer.

Does nitric oxide contribute to the basal vasodilation of pregnancy in conscious rabbits?

Pregnancy produces marked systemic vasodilation, but the mechanism is unknown. Experiments were performed in conscious rabbits to test the hypotheses that increased nitric oxide (NO) production contributes to the increased vascular conductance, but that the contribution varies among vascular beds. Rabbits were instrumented with aortic and vena caval catheters and ultrasonic flow probes implanted around the ascending aorta, superior mesenteric artery, terminal aorta, and/or a femoral artery. Hemodynamic responses to intravenous injection of N(omega)-nitro-L-arginine (L-NA; 20 mg/kg or increasing doses of 2, 5, 10, 15, and 20 mg/kg) were determined in rabbits first before pregnancy (NP) and then at the end of gestation (P). L-NA produced similar increases in arterial pressure between groups, but the following responses were larger (P < 0.05) when the rabbits were pregnant: 1) decreases in total peripheral conductance [-3.7 +/- 0.3 (NP), -5.0 +/- 0.5 (P) ml x min(-1) x mmHg(-1)], 2) decreases in mesenteric conductance [-0.47 +/- 0.05 (NP), -0.63 +/- 0.07 (P) ml x min(-1) x mmHg(-1)], 3) decreases in terminal aortic conductance [-0.43 +/- 0.05 (NP), -0.95 +/- 0.19 ml x min(-1) x mmHg(-1) (P)], and 4) decreases in heart rate [-41 +/- 4 (NP), -62 +/- 5 beats/min (P)]. Nevertheless, total peripheral and terminal aortic conductances remained elevated in the pregnant rabbits (P < 0.05) after L-NA. Furthermore, decreases in cardiac output and femoral conductance were not different between the reproductive states. We conclude that the contribution of NO to vascular tone increases during pregnancy, but only in some vascular beds. Moreover, the data support a role for NO in the pregnancy-induced increase in basal heart rate. Finally, unknown factors in addition to NO must also underlie the basal vasodilation observed during pregnancy.

Patient-focused, family-centered end-of-life medical care: views of the guidelines and bereaved family members.

A fundamental barrier to improving the quality of medical care at the end of life is the lack of measurement tools. The Toolkit of Instruments to Measure End of Life Care (TIME) aims to fill that void by creating measurement tools that capture the patient and family perspective. To develop a conceptual model for a retrospective survey of bereaved family members that incorporates both professional and family perspectives on what constitutes good care at the end of life, a qualitative literature review of existing professional guidelines and six focus groups with bereaved family members from acute care hospitals (n = 2), nursing homes (n = 2), and hospice/VNA home health services (n = 2) was performed. The focus groups were held in Arizona, New York, and Massachusetts and included 42 bereaved family members/friends contacted 3-12 months from the time of patient's death. Domains of care that define quality end-of-life care were defined. Focus group participants defined high quality medical care as: 1) providing dying persons with desired physical comfort; 2) helping dying persons control decisions about medical care and daily routines; 3) relieving family members of the burden of being present at all times to advocate for their loved one; 4) educating family members so they felt confident to care for their loved ones at home; and 5) providing family members with emotional support both before and after the patient's death. The qualitative literature review yielded similar results, except that the professional guidelines did not mention the advocacy burden felt by families. These two sources provided the foundation for a conceptual model of patient-focused, family-centered medical care and a new tool for surveying bereaved family members. Views of bereaved family members' stories and professional guidelines help to identify key domains of quality of end-of-life care. A new survey instrument provides a way to incorporate the perspectives of bereaved family members in measuring the quality of end-of-life care.

Injury surveillance in construction: eye injuries.

Occupational eye injuries are both common and preventable. About 20% of occupational eye injuries occur in construction. To investigate the nature of eye injuries among construction workers, we analyzed a large data set of construction worker injuries. In addition, we interviewed 62 workers with eye injuries to further explore circumstances of eye injury and workers' attitudes and behavior toward the use of eye protection. Eleven percent (363 cases) of the 3,390 construction workers in our data set were treated for eye injuries. Welders, plumbers, insulators, painters/glaziers, supervisors, and electricians had a higher proportion of all injuries due to eye injuries than other trades. Nearly half of the diagnoses were abrasions (46%) followed by foreign objects or splash in the eye (29%), conjunctivitis (10%), and burns (5%). In the interviews with 62 workers, we found that employers very frequently required eye protection for all tasks or for high-risk tasks, and workers report wearing eye protection regularly. However, most did not wear eye protection with top and side shields; if we believe the injuries occurred because a particle or liquid passed between the glasses and the workers' faces, increased use of goggles or full shields would have prevented two-thirds of this group of injuries.

The absence of depth constancy in contour stereograms.

Stereoscopic surfaces constructed from Kanizsa-type illusory contours or explicit luminance contours were tested for three-dimensional (3-D) shape constancy. The curvature of the contours and the apparent viewing distance between the surface and the observer were manipulated. Observers judged which of two surfaces appeared more curved. Experiment 1 allowed eye movements and revealed a bias in 3-D shape judgment with changes in apparent viewing distance, such that surfaces presented far from the observer appeared less curved than surfaces presented close to the observer. The lack of depth constancy was approximately the same for illusory-contour surfaces and for explicit-contour surfaces. Experiment 2 showed that depth constancy for explicit-contour surfaces improved slightly when fixation was required and eye movements were restricted. These experiments suggest that curvature in depth is misperceived, and that illusory-contour surfaces are particularly sensitive to this distortion.

Motion capture depends on signal strength.

When flickering dots are superimposed onto a drifting grating, the dots appear to move coherently with the grating. In this study we examine: (i) how the perceived direction of a compound stimulus composed of superimposed grating and dots, moving in opposite directions with equal speeds, is influenced by the relative strength of the motion signals; (ii) how the perceived speed of a compound stimulus composed of superimposed grating and dots, moving in the same direction but at different speeds, is influenced by the relative strength of the motion signals; and (iii) whether this stimulus is discriminable from its metameric speed match. Dot signal strength was manipulated by using different proportions of signal dots in noise and different dot lifetimes. Both the perceived direction and speed of these compound stimuli depended upon the relative motion-signal strengths of the grating and the dots. Those compound stimuli that appeared coherent were not discriminable from the speed-matched metameric compound stimuli. When the signals were completely integrated into a coherent compound stimulus, the local motion signals were no longer perceptually available, though both contributed to the global percept. These data strongly support a weighted-combination model where the relative weights depend on signal strength, instead of a winner-takes-all model.

Role of angiotensin II in altered baroreflex function of conscious rabbits during late pregnancy.

OBJECTIVE: Pregnancy alters baroreflex control of heart rate in conscious rabbits, but the mechanism for this action is unknown. This study tested the hypothesis that endogenous angiotensin II is the mediator. STUDY DESIGN: To test this hypothesis the baroreflex relationship between arterial pressure and heart rate in conscious rabbits was determined before and after administration of the angiotensin II AT1 receptor antagonist losartan (n = 7) before pregnancy and at the end of gestation. RESULTS: Pregnancy decreased mean arterial pressure, increased heart rate, and modified the reflex by shifting the mean arterial pressure-heart rate relationship to a lower pressure level, by increasing minimum heart rate, and by decreasing baroreflex gain (P < .05). Before pregnancy, losartan decreased baroreflex gain but had no other effect on reflex function. In contrast, during late gestation losartan further decreased mean arterial pressure, further decreased reflex gain, decreased maximum heart rate, and shifted the curve to a lower mean arterial pressure level (P < .05). CONCLUSION: These results suggest that in conscious rabbits during pregnancy endogenous angiotensin II contributes to hypotension-induced tachycardia but does not decrease reflex gain or elevate minimum heart rate.

Stage of life course and social support as a mediator of mood state among persons with disability.

OBJECTIVE: This research seeks to determine which aspects of social support are most effective in mediating mood state among working-age and elderly adults with disability (N = 442). METHODS: Participants were identified through random-digit dialing of telephone exchanges and administration of a disability screen. Multiple regression was used to model multiple aspects of social support while holding sociodemographic and disability indicators constant. RESULTS: Analyses revealed that network size and confidence in the reliability of helping networks are significantly and negatively related to depressed mood. Confidant support was related to lower levels of depressed mood for younger respondents only. Neither marital status, advisor support, nor social integration were related to mood. DISCUSSION: Both instrumental and emotional support are key in mediating depressed mood among this population. We conclude that all types of social support are not equally effective in mediating mood among people with disability.

Injury surveillance in construction: injuries to laborers.

Construction is one of the largest industries in the United States, employing over 7.5 million people. It accounts for 3 times as many accidents as might be expected on a per capita basis. Laborers represent one of 15 job classifications participating in this industry. They have a higher risk of death or injury from a number of causes than do other construction workers.

Women in construction: occupational health and working conditions.

Construction is one of the largest industries in the United States, employing 7.6 million workers, or about 5% of the US work force. More women have taken jobs in the construction industry over the last two decades, as they have in other nontraditional industries. In 1997, there were 8.1 million construction workers, of whom 781,000 (9%) were women. Approximately 2% of those were employed as skilled tradeswomen. There is no disputing that construction work is dangerous. Seventeen percent of all fatal on-the-job injuries occur in construction, which is about three times its 6% share of total employment. In this paper, we review the medical literature on the safety and health hazards for women working in the construction industry. Women have a different pattern of fatal injuries and some differences in patterns of nonfatal injuries than men and report unique problems and concerns related to working in this industry.

Newly designed retraction devices for intestine control during laparoscopic aortic surgery: a comparative study in an animal model.

BACKGROUND: Recent clinical studies have demonstrated the feasibility of laparoscopic surgery for aortic occlusive and aneurysmal disease. However, transperitoneal aortic access is compromised by poor exposure in the operative field from uncontrolled bowel. The retractors that are currently available are inadequate for this task. The development of new retractors would help to facilitate laparoscopic aortic surgery. METHODS: Six female piglets (28-30 kg) in each group underwent laparoscopy with pneumoperitoneum (12 mmHg). Exposure of the infrarenal aorta and cross-clamping were undertaken through a transperitoneal approach. Two paddles inserted in a polyester bilayer (mobile device, group A) or a mesh net fixed to the abdominal wall (fixed device, group B) were used to retain the bowel. Aortotomy and suturing were performed to mimic a vascular procedure. After bleeding was controlled, the intraabdominal pressure (IAP) was lowered to 6 mmHg, and retraction was assessed for 30 min. The main outcome measures were time to deploy the retractors, time to perform the vascular procedure, time to withdraw the devices, and total procedural time. Blood loss and frequency of retraction failure were also recorded. RESULTS: Mean time to deploy the device was 22 +/- 12 min in group A and 36 +/- 34 min in group B (n.s.). Vascular surgery time averaged 60 +/- 24 min in group A and 68 +/- 16 min in group B (n.s.). The times to withdraw the nets were 3.6 +/- 1.2 min and 13.5 +/- 8.2 min, respectively (p < 0.05). Total surgery time was 155 +/- 41 min vs 174 +/- 49 min (n.s.). There were six retraction failures, five in group A and one in group B. When lower IAP was used, there was only one failure in each study group. Mean blood loss was <150 ml in both groups. There were no major complications. CONCLUSIONS: Both methods provided adequate exposure of the infrarenal aorta. Vascular surgery time and blood loss were similar for both groups. The movable device proved more usable and, at lower IAP, more effective. The results of this study demonstrate effective bowel retraction for laparoscopic aortic surgery.