Behavior of the Escape Rate Function in Hyperbolic Dynamical Systems

For a fixed initial reference measure, we study the dependence of the escape rate on the hole for a smooth or piecewise smooth hyperbolic map. First, we prove the existence and Holder continuity of the escape rate for systems with small holes admitting Young towers. Then we consider general holes for Anosov diffeomorphisms, without size or Markovian restrictions. We prove bounds on the upper and lower escape rates using the notion of pressure on the survivor set and show that a variational principle holds under generic conditions. However, we also show that the escape rate function forms a devil's staircase with jumps along sequences of regular holes and present examples to elucidate some of the difficulties involved in formulating a general theory.Comment: 21 pages. v2 differs from v1 only by additions to the acknowledgment

Understanding organizational context and heart failure management in long term care homes in Ontario, Canada

This study examined the prevalence of Control Intervention (CI) use in adult in-patient psychiatric units/hospitals in Ontario and developed a profile of those patients who had CI use during their admission between April 2006 and March 2010. Control intervention types included mechanical/physical, chair prevents rising, acute control medications, and seclusion. The profiles of patients with control intervention use included an examination of sociodemographic, mental health service use, and mental health clinical characteristics.Supported by an unrestricted grant-in-aid from the Heart and Stroke Foundation of Ontari

HST observations of the Local Group dwarf galaxy Leo I

We present deep HST F555W (V) and F814W (I) observations of a central field in the Local Group dwarf spheroidal (dSph) galaxy Leo I. The resulting color-magnitude diagram (CMD) reaches I \simeq 26 and reveals the oldest ~10-15 Gyr old turnoffs. Nevertheless, a horizontal branch is not obvious in the CMD. Given the low metallicity of the galaxy, this likely indicates that the first substantial star formation in the galaxy may have been somehow delayed in Leo I in comparison with the other dSph satellites of the Milky Way. The subgiant region is well and uniformly populated from the oldest turnoffs up to the 1 Gyr old turnoff, indicating that star formation has proceeded in a continuous way, with possible variations in intensity but no big gaps between successive bursts, over the galaxy's lifetime. The structure of the red-clump of core He-burning stars is consistent with the large amount of intermediate-age population inferred from the main sequence and the subgiant region. In spite of the lack of gas in Leo I, the CMD clearly shows star formation continuing until 1 Gyr ago and possibly until a few hundred Myrs ago in the central part of the galaxy.Comment: 26 pages with 8 figures (fig 2 not available electronically). To be published in ApJ, April 1 1999 (vol.514, #2

Nonmalignant respiratory disease mortality among woodworkers participating in the American Cancer Society Cancer Prevention Study-II (CPS-II)

Nonmalignant respiratory disease (NMRD) mortality was examined among woodworkers participating in the American Cancer Society’s CPS-II cohort study. During the 6-year prospective follow-up, there were 97 NMRD deaths among 11,541 men reporting employment in wood-related occupations and 1,338 NMRD deaths among 317,424 men reporting no exposure to wood dust or wood-related jobs. Relative risks, adjusted for age and smoking, were calculated using Poisson regression. A small excess of NMRD was observed among woodworkers. However, the relative risk was higher among woodworkers who did not report exposure to wood dust (RR = 1.52, 95% CI = 1.18–1.97) than those who did (RR = 1.27, 95% CI = 0.91–1.77), and no clear trend with duration of exposure was observed. An excess of NMRD was observed among woodworkers reporting exposure to asbestos (RR = 1.59, 95% CI = 0.85–2.96), as well as the small number of woodworkers reporting exposure to formaldehyde (RR = 1.95, 95% CI = 0.63–6.06), but men not reporting exposure to these substances also had an excess risk. Although limited by a short follow-up period and crude indicators of exposure, the strengths of this analysis were the ability to compare woodworkers to a similar, healthy population and to adjust for the effects of smoking. Cohort studies with better exposure information are needed to examine the role of occupational exposures among woodworkers in the etiology of respiratory disease

Cancer mortality and wood dust exposure among participants in the American Cancer Society Cancer Prevention Study-II (CPS-II).

In 1994, the International Agency for Research on Cancer (IARC) classified wood dust as a human carcinogen, based on very strong evidence of a carcinogenic risk of sino-nasal cancer. Excesses of other cancers, including lung and stomach, have been reported among persons employed in wood industries or occupationally exposed to wood dust, but not as consistently. We investigated such possible associations using the mortality experience of 362,823 men enrolled in the American Cancer Society’s Cancer Prevention Study—II in 1982 and followed up for 6 years. Within this group, 45,399 men (12.5%) reported either employment in a wood-related occupation or exposure to wood dust or both. Among woodworkers, a small but significant excess risk was found for all causes of death (RR 1.17 (95% CI 1.11–1.24)) and for total malignancies (RR 1.17 (1.05–1.30)). Among men who reported exposure to wood dust, there was an elevated risk of total mortality (RR 1.07 (1.03–1.11)), total malignancies (RR 1.08 (1.01—1.15)), and lung cancer (RR 1.17 (1.04–1.31)). Among woodworkers, a significant trend (P = 0.02) of increasing risk of lung cancer with increasing duration of exposure was observed. An unexpected, significantly increased mortality from prostate cancer was observed in both wood-employed and wood-exposed, and a twofold increased risk of fatal brain cancer was seen among the former. Lung cancer mortality was especially high among woodworkers who also reported exposure to asbestos or formaldehyde, and it appears that exposure to these known carcinogens may partly explain the observed increased risks. Excess sino-nasal cancer was not observed, but the number of cases was small

Escape Rates and Physically Relevant Measures for Billiards with Small Holes

We study the billiard map corresponding to a periodic Lorentz gas in 2-dimensions in the presence of small holes in the table. We allow holes in the form of open sets away from the scatterers as well as segments on the boundaries of the scatterers. For a large class of smooth initial distributions, we establish the existence of a common escape rate and normalized limiting distribution. This limiting distribution is conditionally invariant and is the natural analogue of the SRB measure of a closed system. Finally, we prove that as the size of the hole tends to zero, the limiting distribution converges to the smooth invariant measure of the billiard map.Comment: 39 pages, 4 figure

Establishing the Occupational Disease Surveillance System (ODSS) for Ontario: a linkage of administrative data

Introduction Workplace conditions and exposures are important determinants of health. However, identifying and monitoring population-level trends in work-related disease is challenged by existing data limitations. Administrative health databases capture timely and accurate information about disease diagnoses among the Ontario population, but these data do not include work history. Objectives and Approach The Occupational Disease Surveillance System (ODSS), launched in 2017, captures and reports trends in work-related disease in Ontario. A cohort of 2+ million workers was identified from compensation claims (1983-2014). Records were linked through probabilistic and deterministic methods to the Registered Persons Database (1990-2015), and administrative health databases including the Ontario Cancer Registry (1964-2016), hospitalization (2006-2016), ambulatory care (2006-2016) and provincial health insurance plan billing data (1999-2016). Preliminary applications of ODSS have examined risks of 28 cancer sites and 11 non-cancer health conditions. Risks are estimated with Cox proportional hazards models for thousands of industry and occupation groups. Results Linkage of existing administrative databases is an efficient approach for examining risk factors for work-related disease at the population level. ODSS can identify groups of workers by industry or occupation that are at increased risk of disease due to known or suspected workplace conditions and risk factors. For example, ODSS detected elevated risk of lung cancer among known at-risk workers employed in mining and quarrying (HR 1.47, 95% CI 1.33-1.61), transport equipment operating (HR 1.39, 95% CI 1.34-1.44), and construction (HR 1.09, 95% CI 1.06-1.13). Exploratory analyses can also detect previously unknown associations between work-related risk factors and disease. For example, although dermatitis and asthma are common occupational diseases, many causative exposures remain unclear. ODSS is currently being used to further explore potential risk factors. Conclusion/Implications Timely information about work-related disease is crucial to support prevention initiatives to protect workers. This novel linkage identifies existing and emerging trends in occupational disease in Ontario. By capturing work-related risk factors, ODSS serves as a model for other provinces to overcome existing gaps in disease surveillance

Comparison of cancer incidence and mortality in the Norwegian Fire Departments Cohort, 1960-2018

Objectives Elevated risk of cancer at several sites has been reported among firefighters, although with mixed findings. The purpose of this study was to calculate standardised incidence ratios (SIRs) and standardised mortality ratios (SMRs) for cancer and compare them to assess whether use of the different measures could be a source of inconsistencies in findings. Methods The Norwegian Fire Departments Cohort, comprising 4295 male employees who worked at 15 fire departments across Norway, was linked to health outcome registries for the period 1960–2018. SIRs and SMRs were derived using national reference rates. Results Overall, we observed elevated incidence of colon cancer (SIR, 95% CI 1.27, 1.01 to 1.58), mesothelioma (2.59, 1.12 to 5.11), prostate cancer (1.18, 1.03 to 1.34) and all sites combined (1.15, 1.08 to 1.23). Smaller, non-significant elevations were found for mortality of colon cancer (SMR, 95% CI 1.20, 0.84 to 1.67) and mesothelioma (1.66, 0.34 to 4.86), while SMR for prostate cancer was at unity. Potential errors were observed in some of the mortality data, notably for mesothelioma cases. Among those who died of cancer, 3.7% (n=14) did not have a prior diagnosis of malignancy at the same site group. Conclusions Assessment of incidence or mortality did not greatly influence the interpretation of results. The most prominent differences in SIR and SMR appeared to be due to inconsistencies between sites of cancer diagnosis and cause of death. The difference in SIR and SMR for prostate cancer suggested a detection bias from differential screening practices.publishedVersio

Differences in the carcinogenic evaluation of glyphosate between the International Agency for Research on Cancer (IARC) and the European Food Safety Authority (EFSA)

The International Agency for Research on Cancer (IARC) Monographs Programme identifies chemicals, drugs, mixtures, occupational exposures, lifestyles and personal habits, and physical and biological agents that cause cancer in humans and has evaluated about 1000 agents since 1971. Monographs are written by ad hoc Working Groups (WGs) of international scientific experts over a period of about 12 months ending in an eight-day meeting. The WG evaluates all of the publicly available scientific information on each substance and, through a transparent and rigorous process,1 decides on the degree to which the scientific evidence supports that substance's potential to cause or not cause cancer in humans. For Monograph 112,2 17 expert scientists evaluated the carcinogenic hazard for four insecticides and the herbicide glyphosate.3 The WG concluded that the data for glyphosate meet the criteria for classification as a probable human carcinogen. The European Food Safety Authority (EFSA) is the primary agency of the European Union for risk assessments regarding food safety. In October 2015, EFSA reported4 on their evaluation of the Renewal Assessment Report5 (RAR) for glyphosate that was prepared by the Rapporteur Member State, the German Federal Institute for Risk Assessment (BfR). EFSA concluded that ?glyphosate is unlikely to pose a carcinogenic hazard to humans and the evidence does not support classification with regard to its carcinogenic potential?. Addendum 1 (the BfR Addendum) of the RAR5 discusses the scientific rationale for differing from the IARC WG conclusion. Serious flaws in the scientific evaluation in the RAR incorrectly characterise the potential for a carcinogenic hazard from exposure to glyphosate. Since the RAR is the basis for the European Food Safety Agency (EFSA) conclusion,4 it is critical that these shortcomings are corrected