Bomb radiocarbon and tag-recapture dating of sandbar shark (Carcharhinus plumbeus)

The sandbar shark (Carcharhinus plumbeus) was the cornerstone species of western North Atlantic and Gulf of Mexico large coastal shark fisheries until 2008 when they were allocated to a research-only fishery. Despite decades of fishing on this species, important life history parameters, such as age and growth, have not been well known. Some validated age and growth information exists for sandbar shark, but more comprehensive life history information is needed. The complementary application of bomb radiocarbon and tag-recapture dating was used in this study to determine valid age-estimation criteria and longevity estimates for this species. These two methods indicated that current age interpretations based on counts of growth bands in vertebrae are accurate to 10 or 12 years. Beyond these years, we could not determine with certainty when such an underestimation of age begins; however, bomb radiocarbon and tag-recapture data indicated that large adult sharks were considerably older than the estimates derived from counts of growth bands. Three adult sandbar sharks were 20 to 26 years old based on bomb radiocarbon results and were a 5- to 11-year increase over the previous age estimates for these sharks. In support of these findings, the tag-recapture data provided results that were consistent with bomb radiocarbon dating and further supported a longevity that exceeds 30 years for this species

Cause, consequence, and prevalence of spatial structure of white perch (Morone americana) populations in the Chesapeake Bay

Partial migration defines the simultaneous occurrence of migratory and resident groups within populations. Using otolith chemistry (strontium:calcium measures), I documented partial migration for an estuarine-dependent white perch (Morone americana) population in the Patuxent River estuary (Chesapeake Bay, MD). Previous research indicated that as juveniles, a portion of the population remained resident in freshwater natal habitats and another portion dispersed down-estuary into brackish water habitats. I established these behaviors are alternative life history tactics that persist over the lifetime of individuals. Through back-calculation of hatch-dates, juvenile contingents were associated with their respective larval cohorts, indicating that spatial structuring was influenced by time of spawning, and temperature and prey conditions experienced during early life history. Dispersive individuals originated primarily from earlier spawned larval cohorts, characterized by slower growth and higher mortality rates compared to later spawned cohorts, which contributed disproportionately to the resident contingent. Laboratory experiments revealed that partial migration was associated with varying energetic tactics, with dispersive contingent fish exhibiting higher consumption and faster growth rates subsequent to migration. The prevalence of contingent behavior within other white perch populations in Chesapeake Bay was explored using otolith stable isotope (δ18O) values, which had a positive relationship with salinity and together with otolith δ13C serve as a proxy for regional habitats distributed along an estuarine salinity gradient. Resident contingent fish dominated Upper Bay and Potomac River populations, whereas the dispersive contingent dominated within the Choptank, Nanticoke, James, and York Rivers. The consequences of spatial structuring to productivity (spawning stock biomass), stability (variance in spawning stock biomass), and resilience (years to rebuild the population) of white perch populations were examined using an age-structured simulation model. Increased representation of migratory fish resulted in increased population productivity and resilience, whereas presence of the resident contingent within the population contributed to stability. Increased population stability and productivity also occurred when the abundance of the two contingents varied inversely to one another over time (i.e., asynchronous dynamics). The different roles contingents play in mediating population dynamics and long-term persistence highlights the importance of managing for conservation of spatial structure within fish populations

Age validation of quillback rockfish (Sebastes maliger) using bomb radiocarbon

Rockfishes (Sebastes spp.) support one of the most economically important f isheries of the Pacific Northwest and it is essential for sustainable management that age estimation procedures be validated for these species. Atmospheric testing of thermonuclear devices during the 1950s and 1960s created a global radiocarbon (14C) signal in the ocean environment that scientists have identified as a useful tracer and chronological marker in natural systems. In this study, we first demonstrated that fewer samples are necessary for age validation using the bomb-generated 14C signal by emphasizing the utility of the time-specific marker created by the initial rise of bomb-14C. Second, the bomb-generated 14C signal retained in fish otoliths was used to validate the age and age estimation method of the quillback rockfish (Sebastes maliger) in the waters of southeast Alaska. Radiocarbon values from the first year’s growth of quillback rockfish otoliths were plotted against estimated birth year to produce a 14C time series spanning 1950 to 1985. The initial rise in bomb-14C from prebomb levels (~ –90‰) occurred in 1959 [±1 year] and 14C levels rose relatively rapidly to peak Δ14C values in 1967 (+105.4‰) and subsequently declined through the end of the time series in 1985 (+15.4‰). The agreement between the year of initial rise of 14C levels from the quillback rockfish time series and the chronology determined for the waters of southeast Alaska from yelloweye rockfish (S. ruberrimus) otoliths validated the aging method for the quillback rockfish. The concordance of the entire quillback rockfish 14C time series with the yelloweye rockfish time series demonstrated the effectiveness of this age validation technique, confirmed the longevity of the quillback rockfish up to a minimum of 43 years, and strongly confirms higher age estimates of u

Direct Democracy, State Governments, and the Re-energized GMO Debate : Implications of California's Proposition 37

It is often convenient to divide the world into those countries that have been generally accepting of agricultural biotechnology and those that are not. While the debate over biotechnology continues to rage where biotechnology has not been accepted, in adopting countries the debate is often seen as being over. This has been the case for the United States. In fact, the debate over agricultural biotechnology has continued but has not had a high profile. The debate in the United States has been re-energized due to California's 2012 Proposition 37, which would have required labeling of GM-foods in the state. Given the importance of California in both the national food system and national politics, Proposition 37 had national and international ramifications. While Proposition 37 was rejected by a narrow margin, it has spurred other state- and municipal-level initiatives regarding the regulation of biotechnology. This article examines the political dynamics underlying Proposition 37 and the economic implications of similar regulatory initiatives becoming law in the future. The article argues that proposed measures can have a major influence on attempts to regulate in other jurisdictions

Use of telehealth for facilitating the diagnostic assessment of Autism Spectrum Disorder (ASD): A scoping review

There is a significant delay between seeking help and a confirmed diagnosis of Autism Spectrum Disorder (ASD). This delay can lead to poor outcomes for both the families and individuals. Telehealth potentially offers a way of improving the diagnostic pathway for ASD. We conducted a scoping review examining which telehealth approaches are used in the diagnosis and assessment of ASD in children and adults, whether they are feasible and acceptable, and how they compare with face-to-face diagnosis and assessment methods. A search for all peer-reviewed articles, combining the terms of autism and telehealth was conducted from 2000 to 2019. A total of 10 studies were identified for inclusion in the review. This review of the literature found there to be two methods of using telehealth: (a) Real-Time method e.g. video conferencing that enables teams in different areas to consult with the families and to assess the child/adult in real time and (b) A Store-and-Forward method as Naturalistic Observation Diagnostic Assessment (NODA) system to upload videos of child’s behaviors to a webportal that enables the clinicians to make an assessment remotely. The findings were positive, finding there to be high agreement in terms of the diagnosis between remote methods and face to face methods and with high levels of satisfaction among the families and clinicians. This field is in the very early stages and so only studies with small sample size using surveys and interviews were identified but the findings suggest that there is potential for telehealth methods to improve access to assessment and diagnosis of ASD used in conjunction with existing methods, especially for those with clear autism traits and adults with ASD. Larger randomised controlled trials of this technology are warranted

Initial data for two Kerr-like black holes

We prove the existence of a family of initial data for the Einstein vacuum equation which can be interpreted as the data for two Kerr-like black holes in arbitrary location and with spin in arbitrary direction. When the mass parameter of one of them is zero, this family reduces exactly to the Kerr initial data. The existence proof is based on a general property of the Kerr metric which can be used in other constructions as well. Further generalizations are also discussed.Comment: revtex, 5 pages, no figure

“Maybe I Made Up the Whole Thing”: Placebos and Patients’ Experiences in a Randomized Controlled Trial

Patients in the placebo arms of randomized controlled trials (RCT) often experience positive changes from baseline. While multiple theories concerning such “placebo effects” exist, peculiarly, none has been informed by actual interviews of patients undergoing placebo treatment. Here, we report on a qualitative study (n = 27) embedded within a RCT (n = 262) in patients with irritable bowel syndrome. Besides identical placebo acupuncture treatment in the RCT, the qualitative study patients also received an additional set of interviews at the beginning, midpoint, and end of the trial. Interviews of the 12 qualitative subjects who underwent and completed placebo treatment were transcribed. We found that patients (1) were persistently concerned with whether they were receiving placebo or genuine treatment; (2) almost never endorsed “expectation” of improvement but spoke of “hope” instead and frequently reported despair; (3) almost all reported improvement ranging from dramatic psychosocial changes to unambiguous, progressive symptom improvement to tentative impressions of benefit; and (4) often worried whether their improvement was due to normal fluctuations or placebo effects. The placebo treatment was a problematic perturbation that provided an opportunity to reconstruct the experiences of the fluctuations of their illness and how it disrupted their everyday life. Immersion in this RCT was a co-mingling of enactment, embodiment and interpretation involving ritual performance and evocative symbols, shifts in bodily sensations, symptoms, mood, daily life behaviors, and social interactions, all accompanied by self-scrutiny and re-appraisal. The placebo effect involved a spectrum of factors and any single theory of placebo—e.g. expectancy, hope, conditioning, anxiety reduction, report bias, symbolic work, narrative and embodiment—provides an inadequate model to explain its salubrious benefits

Rapid, B1B_1-insensitive, dual-band quasi-adiabatic saturation transfer with optimal control for complete quantification of myocardial ATP flux

Purpose: Phosphorus saturation-transfer experiments can quantify metabolic fluxes non-invasively. Typically, the forward flux through the creatine-kinase reaction is investigated by observing the decrease in phosphocreatine (PCr) after saturation of $\gamma$-ATP. The quantification of total ATP utilisation is currently under-explored, as it requires simultaneous saturation of inorganic phosphate (Pi) and PCr. This is challenging, as currently available saturation pulses reduce the already-low $\gamma$-ATP signal present. Methods: Using a hybrid optimal-control and Shinnar-Le-Roux method, a quasi-adiabatic RF pulse was designed for the dual-saturation of PCr and Pi to enable determination of total ATP utilisation. The pulses were evaluated in Bloch equation simulations, compared with a conventional hard-cosine DANTE saturation sequence, before application to perfused rat hearts at 11.7 Tesla. Results: The quasi-adiabatic pulse was insensitive to a $>2.5$-fold variation in $B_1$, producing equivalent saturation with a 53% reduction in delivered pulse power and a 33-fold reduction in spillover at the minimum effective $B_1$. This enabled the complete quantification of the synthesis and degradation fluxes for ATP in 30-45 minutes in the perfused rat heart. While the net synthesis flux ($4.24\pm0.8$ mM/s, SEM) was not significantly different from degradation flux ($6.88\pm2$ mM/s, $p=0.06$) and both measures are consistent with prior work, nonlinear error analysis highlights uncertainties in the Pi-to-ATP measurement that may explain a trend suggesting a possible imbalance. Conclusion: This work demonstrates a novel quasi-adiabatic dual-saturation RF pulse with significantly improved performance that can be used to measure ATP turnover in the heart in vivo.Comment: 26 pages, Accepted at Magnetic Resonance in Medicine, 24/11/2020 [This version post reviews

Correction to : Efficacy and Safety of Switching to Ixekizumab in Etanercept Non-Responders: A Subanalysis from Two Phase III Randomized Clinical Trials in Moderate-to-Severe Plaque Psoriasis (UNCOVER-2 and -3)

Altres ajuts: NCT01597245 and NCT01646177 and the post hoc analyses of these studies presented in this manuscript were funded by Eli Lilly and Company.Patients with psoriasis who have an inadequate response to one biologic may benefit from switching to a new biologic, such as ixekizumab, a high affinity monoclonal antibody that selectively targets interleukin (IL)-17A. Our aim was to assess the response to ixekizumab in patients with moderate-to-severe plaque psoriasis who did not respond adequately to etanercept using a post-hoc analysis in two phase III studies. For the subanalyses in two phase III trials (UNCOVER-2 and -3), non-response was defined by either failure to have a static physician global assessment (sPGA) of 0/1 in UNCOVER-2 or failure to have at least 75% improvement in psoriasis area and severity index (PASI 75) in UNCOVER-3 at Week 12 of each study. Non-responders treated with twice-weekly etanercept 50 mg in the first 12 weeks received two injections of placebo at Week 12 (4-week wash-out period), followed by ixekizumab every 4 weeks (Q4W) for Weeks 16-60. Non-responders to placebo in the first 12 weeks were administered ixekizumab 160 mg at Week 12, followed by ixekizumab Q4W for Weeks 16-60. After switching to ixekizumab Q4W, a substantial proportion of patients with moderate-to-severe psoriasis who did not respond to etanercept experienced rapid and durable improvement in all efficacy evaluations. Among sPGA 0/1 (UNCOVER-2) and PASI 75 (UNCOVER-3) non-responders to etanercept, 73.0% achieved sPGA 0/1 and 78.2% achieved PASI 75, respectively, after 12 weeks of ixekizumab treatment. Safety profiles in patients switched from etanercept to ixekizumab were similar to those in patients switched from placebo to ixekizumab. Patients who were non-responders to etanercept after 12 weeks, as defined by failure to meet sPGA 0/1 (UNCOVER-2) or PASI 75 (UNCOVER-3), achieved high levels of response 12 weeks after switching to ixekizumab. Studies are registered with ClinicalTrials.gov (NCT01597245 and NCT01646177)

Optimization of surgical tourniquet usage to improve patient outcomes: Translational cross-disciplinary implications of a surgical practice survey

Tourniquet use is common practice in many millions of orthopaedic procedures annually. Recent reviews of risks and benefits of surgical tourniquet use have primarily involved meta-analyses, many of which have forgone a comprehensive risk-benefit analysis to simply question whether “tourniquet or no tourniquet” use produces improved patient outcomes, often leading to limited, inconclusive, or conflicting results. To investigate further, a pilot survey was undertaken to determine current practices, opinions, and understandings among orthopaedic surgeons in Canada regarding use of surgical tourniquets in total knee arthroplasties (TKAs). Results of the pilot survey showed a wide range of understanding and practice associated with tourniquet use in TKAs, especially regarding tourniquet pressures and tourniquet times, two key factors known from basic research and clinical studies to impact the safety and efficacy of tourniquet use. The wide variation of use indicated by the survey results reveals important implications for surgeons, researchers, educators, and biomedical engineers, to better understand the association between key tourniquet parameters and outcomes assessed in research, which may be factors leading to their often limited, inconclusive, and conflicting results. Lastly, we provide an overview of the overly simplified assessments of tourniquet use in meta-analyses, whose conclusions may not provide an understanding of how or whether key tourniquet parameters might be optimized to retain the benefits of tourniquet use while mitigating the associated real or perceived risks