24 research outputs found

    Maximal aerobic and anaerobic power generation in large crocodiles versus mammals: implications for dinosaur gigantothermy

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    Inertial homeothermy, the maintenance of a relatively constant body temperature that occurs simply because of large size, is often applied to large dinosaurs. Moreover, biophysical modelling and actual measurements show that large crocodiles can behaviourally achieve body temperatures above 30°C. Therefore it is possible that some dinosaurs could achieve high and stable body temperatures without the high energy cost of typical endotherms. However it is not known whether an ectothermic dinosaur could produce the equivalent amount of muscular power as an endothermic one. To address this question, this study analyses maximal power output from measured aerobic and anaerobic metabolism in burst exercising estuarine crocodiles, Crocodylus porosus, weighing up to 200 kg. These results are compared with similar data from endothermic mammals. A 1 kg crocodile at 30°C produces about 16 watts from aerobic and anaerobic energy sources during the first 10% of exhaustive activity, which is 57% of that expected for a similarly sized mammal. A 200 kg crocodile produces about 400 watts, or only 14% of that for a mammal. Phosphocreatine is a minor energy source, used only in the first seconds of exercise and of similar concentrations in reptiles and mammals. Ectothermic crocodiles lack not only the absolute power for exercise, but also the endurance, that are evident in endothermic mammals. Despite the ability to achieve high and fairly constant body temperatures, therefore, large, ectothermic, crocodile-like dinosaurs would have been competitively inferior to endothermic, mammal-like dinosaurs with high aerobic power. Endothermy in dinosaurs is likely to explain their dominance over mammals in terrestrial ecosystems throughout the Mesozoic.Roger S. Seymou

    Lifetime climate impacts of diet transitions: a novel climate change accounting perspective

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    Dietary transitions, such as eliminating meat consumption, have been proposed as one way to reduce the climate impact of the global and regional food systems. However, it should be ensured that replacement diets are indeed nutritious and that climate benefits are accurately accounted for. This study uses New Zealand food consumption as a case study for exploring the cumulative climate impact of adopting the national dietary guidelines and the substitution of meat from hypothetical diets. The new GWP* metric is used as it was designed to better reflect the climate impacts of the release of methane than the de facto standard 100-year Global Warming Potential metric (GWP100). A transition at age 25 to the hypothetical dietary guideline diet reduces cumulative warming associated with diet by 7 to 9% at the 100th year compared with consuming the average New Zealand diet. The reduction in diet-related cumulative warming from the transition to a hypothetical meat-substituted diet varied between 12 and 15%. This is equivalent to reducing an average individual's lifetime warming contribution by 2 to 4%. General improvements are achieved for nutrient intakes by adopting the dietary guidelines compared with the average New Zealand diet; however, the substitution of meat items results in characteristic nutrient differences, and these differences must be considered alongside changes in emission profiles.fals

    Correction: Barnsley et al. Lifetime Climate Impacts of Diet Transitions: A Novel Climate Change Accounting Perspective. Sustainability 2021, 13, 5568

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    The authors would like to make the following corrections about the published paper The changes are as follows: (1) Replacing the Conflicts of Interest: Conflicts of Interest: The authors declare no conflict of interest. with Conflict of Interest: The Ministry for Primary Industries (MPI) is the regulator for New Zealand’s entire primary sector. As regulator, we are responsive to the needs of all food-producing industries and have a wide range of other responsibilities. In a practical sense, our role includes protecting New Zealand from biological risk, increasing food production, minimising environmental impacts, and ensuring the food we produce in New Zealand is safe for consumers. The primary sector is wide-ranging and includes our arable and horticulture industries, as well as our red meat, dairy, fisheries and aquaculture industries. The authors apologize for any inconvenience caused and state that the scientific conclusions are unaffected. The original publication has also been updated.fals

    Exhaustive exercise training enhances aerobic capacity in American alligator (Alligator mississippiensis)

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    The oxygen transport system in mammals is extensively remodelled in response to repeated bouts of activity, but many reptiles appear to be ‘metabolically inflexible’ in response to exercise training. A recent report showed that estuarine crocodiles (Crocodylus porosus) increase their maximum metabolic rate in response to exhaustive treadmill training, and in the present study, we confirm this response in another crocodilian, American alligator (Alligator mississippiensis). We further specify the nature of the crocodilian training response by analysing effects of training on aerobic [citrate synthase (CS)] and anaerobic [lactate dehydrogenase (LDH)] enzyme activities in selected skeletal muscles, ventricular and skeletal muscle masses and haematocrit. Compared to sedentary control animals, alligators regularly trained for 15 months on a treadmill (run group) or in a flume (swim group) exhibited peak oxygen consumption rates higher by 27 and 16%, respectively. Run and swim exercise training significantly increased ventricular mass (~11%) and haematocrit (~11%), but not the mass of skeletal muscles. However, exercise training did not alter CS or LDH activities of skeletal muscles. Similar to mammals, alligators respond to exercise training by increasing convective oxygen transport mechanisms, specifically heart size (potentially greater stroke volume) and haematocrit (increased oxygen carrying-capacity of the blood). Unlike mammals, but similar to squamate reptiles, alligators do not also increase citrate synthase activity of the skeletal muscles in response to exercise

    The emergence of semantic categorization in early visual processing: ERP indices of animal vs. artifact recognition

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    BACKGROUND: Neuroimaging and neuropsychological literature show functional dissociations in brain activity during processing of stimuli belonging to different semantic categories (e.g., animals, tools, faces, places), but little information is available about the time course of object perceptual categorization. The aim of the study was to provide information about the timing of processing stimuli from different semantic domains, without using verbal or naming paradigms, in order to observe the emergence of non-linguistic conceptual knowledge in the ventral stream visual pathway. Event related potentials (ERPs) were recorded in 18 healthy right-handed individuals as they performed a perceptual categorization task on 672 pairs of images of animals and man-made objects (i.e., artifacts). RESULTS: Behavioral responses to animal stimuli were ~50 ms faster and more accurate than those to artifacts. At early processing stages (120–180 ms) the right occipital-temporal cortex was more activated in response to animals than to artifacts as indexed by posterior N1 response, while frontal/central N1 (130–160) showed the opposite pattern. In the next processing stage (200–260) the response was stronger to artifacts and usable items at anterior temporal sites. The P300 component was smaller, and the central/parietal N400 component was larger to artifacts than to animals. CONCLUSION: The effect of animal and artifact categorization emerged at ~150 ms over the right occipital-temporal area as a stronger response of the ventral stream to animate, homomorphic, entities with faces and legs. The larger frontal/central N1 and the subsequent temporal activation for inanimate objects might reflect the prevalence of a functional rather than perceptual representation of manipulable tools compared to animals. Late ERP effects might reflect semantic integration and cognitive updating processes. Overall, the data are compatible with a modality-specific semantic memory account, in which sensory and action-related semantic features are represented in modality-specific brain areas

    Prevalence of Overweight and Obesity among Type 2 Diabetes Patients attending Usmanu Dan Fodiyo University Teaching Hospital, Sokoto, Nigeria

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    Objective: To determine the proximate composition and anti-nutrient content of new varieties of cowpea and maize released by the Institute for Agricultural Research [IAR], Ahmadu Bello University [ABU] – Zaria. Materials and Methods: Samples of eleven varieties each of cowpea and maize were collected from their respective breeders in the Department of Plant Science, IAR, ABU, Zaria. Carbohydrate, crude protein, ash, moisture, crude lipid and crude fiber contents were determined using standard methods. Determination of phytate, tannin, cyanide, saponin and oxalate were conducted on the cowpea varieties while for the maize varieties, all the above listed anti-nutrients were determined except oxalate. The various analyses were expressed as mean + standard deviation and analyzed using one-way analysis of variance [ANOVA]. Results: Crude protein content in the cowpea varieties ranged from 22.66 to 24.10% and for maize 9.62 to 10.16%, carbohydrate ranged between 56.48 and 59.70% in cowpea and 72.88 to 74.35% in maize, lipid from 2.16 to 3.14% in cowpea and 0.23 to 1.80% in maize, ash from 2.68 to 3.40% in cowpea and 2.84 to 3.66% in maize, moisture from 8.12 to 9.46% in cowpea and 9.66 to 10.16% in maize and crude fibre from 3.30 to 4.42% in cowpea and 1.42 to 2.12% in maize. Phytate content varied from 1.04 to 1.88% in cowpea and 0.16 to 0.26% in maize, tannin from 0.18 to 0.48% in cowpea and 0.02 to 0.18% in maize, cyanide from 0.04 to 0.16% in cowpea and 0.10 to 0.16% in maize and saponin from 0.02 to 0.08% in cowpea and 0.0002 to 0.0004% in maize. Oxalate ranged from 0.00 to 0.004% in cowpea. Conclusion: The study showed that the IAR released cowpea and maize varieties were nutritionally rich, low in anti-nutrients and suitable for local consumption and industrial utilization. Key Words:Nutrients, Anti-nutrients, Cowpea, Maize, New varietie

    Postlicensure herpes zoster vaccine effectiveness: Systematic review protocol

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    © 2021 BMJ Publishing Group. All rights reserved. Introduction Herpes zoster (HZ) and associated complications inflict substantial morbidity and associated healthcare and socioeconomic burdens. Current treatments are not fully effective, especially among the most vulnerable populations. Two HZ vaccines are available and are part of the national immunisation programmes in many countries. This review will evaluate the effectiveness of zoster vaccines against incident HZ and postherpetic neuralgia in adults 50 years and older. Methods and analysis The key information sources that will be searched include MEDLINE (Ovid), Embase (Ovid), Cochrane libraries and CINAHL. This search will consider postlicensure observational studies published in all languages between 2006 and 2020 that assessed the effectiveness of HZ/zoster vaccines in adults 50 years and older. The identification of studies will be complemented with the search of reference lists and citations, and contact with authors of papers to request missing or additional data, where required. Following the search, all identified citations will be collated, and duplicates will be removed. Titles and abstracts will then be screened by two independent reviewers for assessment against the inclusion criteria for the review. Selected studies will follow the process of critical appraisal, data extraction and data synthesis. Statistical analyses will be performed using a random-effect model. Ethics and dissemination Formal ethical approval is not required, as primary data will not be collected. The review will be disseminated in peer-reviewed publications and conference presentations.</jats:p

    Postlicensure herpes zoster vaccine effectiveness: Systematic review protocol

    No full text
    © 2021 BMJ Publishing Group. All rights reserved. Introduction Herpes zoster (HZ) and associated complications inflict substantial morbidity and associated healthcare and socioeconomic burdens. Current treatments are not fully effective, especially among the most vulnerable populations. Two HZ vaccines are available and are part of the national immunisation programmes in many countries. This review will evaluate the effectiveness of zoster vaccines against incident HZ and postherpetic neuralgia in adults 50 years and older. Methods and analysis The key information sources that will be searched include MEDLINE (Ovid), Embase (Ovid), Cochrane libraries and CINAHL. This search will consider postlicensure observational studies published in all languages between 2006 and 2020 that assessed the effectiveness of HZ/zoster vaccines in adults 50 years and older. The identification of studies will be complemented with the search of reference lists and citations, and contact with authors of papers to request missing or additional data, where required. Following the search, all identified citations will be collated, and duplicates will be removed. Titles and abstracts will then be screened by two independent reviewers for assessment against the inclusion criteria for the review. Selected studies will follow the process of critical appraisal, data extraction and data synthesis. Statistical analyses will be performed using a random-effect model. Ethics and dissemination Formal ethical approval is not required, as primary data will not be collected. The review will be disseminated in peer-reviewed publications and conference presentations.</jats:p
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