Systematic bias in estimates of reproductive potential of cod stocks: implications for stock/recruit theory and management

Stock/recruit relationships, describing the relationship between the parental population and the number of offspring produced, are a central tool in population ecology. For fish populations the stock/recruit relationship uses spawning stock biomass (SSB) to represent reproductive potential of the parental population. This assumes that the proportion of SSB comprised of females and the relative fecundity (number of eggs produced per unit mass) are both constant over time. To test these two constancy assumptions female-only spawner biomass (FSB) and total egg production (TEP) were estimated for the Northeast Arctic cod stock over a 56-year time period (1946-2001). During that time period the proportion of females (FSB/SSB) varied between 24 and 68% and the variation was systematic with length such that SSB became more female-biased as the mean length of spawners increased and more male-biased as mean length decreased. Over the same time period, relative fecundity of the stock (TEP/SSB) varied between 115 and 355 eggs g-1 and, like FSB/SSB, was significantly, positively correlated mean length of spawners. Because both FSB/SSB and TEP/SSB covaried with length composition, SSB is systematically biased estimate of reproductive potential. FSB and TEP were evaluated as possible replacements for SSB in stock/recruit relationship. Both indices gave a different interpretation of the recruitment response to reductions in stock size (over-compensatory) compared to that obtained using SSB (either compensatory or depensatory). The threshold level of stock size below which recruitment becomes impaired was estimated for each of the different stock/recruit relationships using piecewise linear regression. There was no difference between SSB and FSB in the assessment of stock status, however, in recent years (1980-2001) TEP fell below the threshold level more frequently than SSB fell below. This suggests that using SSB as a measure of stock reproductive potential may lead to overly optimistic assessments of stock status

LOWER LEG MORPHOLOGY AND STRETCH-SHORTENING CYCLE PERFORMANCE IN YOUNG AND ELDERLY MALES

The purpose of this investigation was to examine bone and muscle characteristics of the lower leg and stretch-shortening cycle capabilities of the ankle in young (22.3 ± 1.3 yrs) and elderly (67.5 ± 3.3 yrs) males. Peripheral quantitiative computed tomography (pQCT) was utilized to assess bone stress-strain index, bone ultimate fracture load, muscle density, muscle cross-sectional area (CSA), fat CSA and muscle+bone CSA. Maximal voluntary isometric plantarflexion (MVIP) force and force-velocity measurments during a countermovement hop (CMH) and drop hops from 20, 30 and 40 cm (DH20, DH30, DH40) were also measured. Bone stress-strain index was significantly higher in young males as well as muscle density, muscle CSA and muscle+bone CSA in comparison to elderly males. MVIP peak force and rate of force development was significantly higher in young males in comparsion to elderly males as well. An analysis of the force-velocity curves indicated that young males had significanlty higher levels of force and velocity in both the eccentric and concentric phase during the CMH, DH20, DH30 and DH40 in comparsion to elderly males. The data from this investigation indicate that aging potentially negatively influences lower leg bone and muscle strength and this may be reflected in lower stretch-shortening cycle capabilities of the ankle

FORCE-VELOCITY PROFILES OF DANCERS AND ENDURANCE RUNNERS DURING ANKLE-SPECIFIC STRETCH-SHORTENING CYCLE TASKS

While dance and endurance running drastically differ from one another in an anecdotal context, both modalities of movement necessitate proficient stretch-shortening cycle (SSC) function about the ankle-joint. The purpose of the present study was to compare force-velocity profiles in dancers (n=6) and endurance runners (n=6) during a countermovement hop (CMH) and 30 cm drop hop (DH30) to elucidate differences between groups that would potentially stimulate effective training regimens. Average relative force-time, velocity-time and force-velocity curves were generated for each group’s CMH and DH30. Dancers hopped significantly higher (p ≤ 0.05) than endurance runners in both hopping tasks. Data from this investigation indicate that dancers and runners have distinctive temporal patterns and force production characteristics during ankle-joint SSC tasks with respect to the eccentric and concentric phase. This may be due to the unique SSC characteristics of each group’s corresponding training protocols

Unsupervised morphological segmentation in a language with reduplication

We present an extension of the Morfessor Base line model of unsupervised morphological seg mentation (Creutz and Lagus, 2007) that in corporates abstract templates for reduplication, a typologically common but computationally underaddressed process. Through a detailed in vestigation that applies the model to Maori, the ¯ Indigenous language of Aotearoa New Zealand, we show that incorporating templates improves Morfessor’s ability to identify instances of redu plication, and does so most when there are multiple minimally-overlapping templates. We present an error analysis that reveals important factors to consider when applying the extended model and suggests useful future directions

Estimated Risk of HIV Acquisition and Practice for Preventing Occupational Exposure: A Study of Healthcare Workers at Tumbi and Dodoma Hospitals, Tanzania.

Health care workers (HCWs) are at risk of acquiring human immuno-deficiency virus (HIV) and other infections via exposure to infectious patients' blood and body fluids. The main objective of this study was to estimate the risk of HIV transmission and examine the practices for preventing occupational exposures among HCWs at Tumbi and Dodoma Hospitals in Tanzania. This study was carried out in two hospitals, namely, Tumbi in Coast Region and Dodoma in Dodoma Region. In each facility, hospital records of occupational exposure to HIV infection and its management were reviewed. In addition, practices to prevent occupational exposure to HIV infection among HCWs were observed. The estimated risk of HIV transmission due to needle stick injuries was calculated to be 7 cases per 1,000,000 HCWs-years. Over half of the observed hospital departments did not have guidelines for prevention and management of occupational exposure to HIV infections and lacked well displayed health and safety instructions. Approximately, one-fifth of the hospital departments visited failed to adhere to the instructions pertaining to correlation between waste materials and the corresponding colour coded bag/container/safety box. Seventy four percent of the hospital departments observed did not display instructions for handling infectious materials. Inappropriate use of gloves, lack of health and safety instructions, and lack of use of eye protective glasses were more frequently observed at Dodoma Hospital than at Tumbi Hospital. The poor quality of the hospital records at the two hospitals hampered our effort to characterise the risk of HIV infection acquisition by HCWs. Greater data completeness in hospital records is needed to allow the determination of the actual risk of HIV transmission for HCWs. To further reduce the risk of HIV infection due to occupational exposure, hospitals should be equipped with sufficient personal protective equipment (PPE) and HCWs should be reminded of the importance of adhering to universal precautions

Implementation, adoption and perceptions of telemental health during the COVID-19 pandemic: a systematic review

BACKGROUND: Early in 2020, mental health services had to rapidly shift from face-to-face models of care to delivering the majority of treatments remotely (by video or phone call or occasionally messaging) due to the COVID-19 pandemic. This resulted in several challenges for staff and patients, but also in benefits such as convenience or increased access for people with impaired mobility or in rural areas. There is a need to understand the extent and impacts of telemental health implementation, and barriers and facilitators to its effective and acceptable use. This is relevant both to future emergency adoption of telemental health, and to debates on its future use in routine mental health care. OBJECTIVE: To investigate the adoption and impacts of telemental health approaches during the COVID-19 Pandemic, and facilitators and barriers to optimal implementation. METHODS: Four databases (PubMed, PsycINFO, CINAHL and Web of Science) were searched for primary research relating to remote working, mental health care, and the COVID-19 pandemic. Preprint servers were also searched. Results of studies were synthesised using framework synthesis. RESULTS: A total of 77 papers met our inclusion criteria. In most studies, the majority of contacts could be transferred to a remote form during the pandemic, and good acceptability to service users and clinicians tended to be reported, at least where the alternative to remote contacts was interrupting care. However, a range of impediments to dealing optimal care by this means were also identified. CONCLUSIONS: Implementation of telemental health allowed some continuing support to the majority of service users during the COVID-19 pandemic and has value in an emergency situation. However, not all service users can be reached by this means, and better evidence is now needed on long-term impacts on therapeutic relationships and quality of care, and on impacts on groups at risk of digital exclusion and how to mitigate these. CLINICALTRIAL

Early impacts of the COVID-19 pandemic on mental health care and on people with mental health conditions: framework synthesis of international experiences and responses

PURPOSE: The COVID-19 pandemic has many potential impacts on people with mental health conditions and on mental health care, including direct consequences of infection, effects of infection control measures and subsequent societal changes. We aimed to map early impacts of the pandemic on people with pre-existing mental health conditions and services they use, and to identify individual and service-level strategies adopted to manage these. METHODS: We searched for relevant material in the public domain published before 30 April 2020, including papers in scientific and professional journals, published first person accounts, media articles, and publications by governments, charities and professional associations. Search languages were English, French, German, Italian, Spanish, and Mandarin Chinese. Relevant content was retrieved and summarised via a rapid qualitative framework synthesis approach. RESULTS: We found 872 eligible sources from 28 countries. Most documented observations and experiences rather than reporting research data. We found many reports of deteriorations in symptoms, and of impacts of loneliness and social isolation and of lack of access to services and resources, but sometimes also of resilience, effective self-management and peer support. Immediate service challenges related to controlling infection, especially in inpatient and residential settings, and establishing remote working, especially in the community. We summarise reports of swiftly implemented adaptations and innovations, but also of pressing ethical challenges and concerns for the future. CONCLUSION: Our analysis captures the range of stakeholder perspectives and experiences publicly reported in the early stages of the COVID-19 pandemic in several countries. We identify potential foci for service planning and research

Demographic, risk behaviour and personal network variables associated with prevalent hepatitis C, hepatitis B, and HIV infection in injection drug users in Winnipeg, Canada

BACKGROUND: Previous studies have used social network variables to improve our understanding of HIV transmission. Similar analytic approaches have not been undertaken for hepatitis C (HCV) or B (HBV), nor used to conduct comparative studies on these pathogens within a single setting. METHODS: A cross-sectional survey consisting of a questionnaire and blood sample was conducted on injection drug users in Winnipeg between December 2003 and September 2004. Logistic regression analyses were used to correlate respondent and personal network data with HCV, HBV and HIV prevalence. RESULTS: At the multivariate level, pathogen prevalence was correlated with both respondent and IDU risk network variables. Pathogen transmission was associated with several distinct types of high-risk networks formed around specific venues (shooting galleries, hotels) or within users who are linked by their drug use preferences. Smaller, isolated pockets of IDUs also appear to exist within the larger population where behavioural patterns pose a lesser risk, unless or until, a given pathogen enters those networks. CONCLUSION: The findings suggest that consideration of both respondent and personal network variables can assist in understanding the transmission patterns of HCV, HBV, and HIV. It is important to assess these effects for multiple pathogens within one setting as the associations identified and the direction of those associations can differ between pathogens