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Nyborg Spence posted an update 6 months, 1 week ago
Despite having a trunk that weighs over 100 kg, elephants mainly feed on lightweight vegetation. How do elephants manipulate such small items? In this experimental and theoretical investigation, we filmed elephants at Zoo Atlanta showing that they can use suction to grab food, performing a behaviour that was previously thought to be restricted to fishes. We use a mathematical model to show that an elephant’s nostril size and lung capacity enables them to grab items using comparable pressures as the human lung. Ultrasonographic imaging of the elephant sucking viscous fluids show that the elephant’s nostrils dilate up to in radius, which increases the nasal volume by . Based on the pressures applied, we estimate that the elephants can inhale at speeds of over 150 m s-1, nearly 30 times the speed of a human sneeze. These high air speeds enable the elephant to vacuum up piles of rutabaga cubes as well as fragile tortilla chips. We hope these findings inspire further work in suction-based manipulation in both animals and robots.Multiple brain injury criteria (BIC) are developed to quickly quantify brain injury risks after head impacts. BI9787 These BIC originated from different head impact types (e.g. sports and car crashes) are widely used in risk evaluation. However, the accuracy of using the BIC on brain injury risk estimation across head impact types has not been evaluated. Physiologically, brain strain is often considered the key parameter of brain injury. To evaluate the BIC’s risk estimation accuracy across five datasets comprising different head impact types, linear regression was used to model 95% maximum principal strain, 95% maximum principal strain at the corpus callosum and cumulative strain damage (15%) on 18 BIC. The results show significantly different relationships between BIC and brain strain across datasets, indicating the same BIC value may suggest different brain strain across head impact types. The accuracy of brain strain regression is generally decreasing if the BIC regression models are fitted on a dataset with a different type of head impact rather than on the dataset with the same type. Given this finding, this study raises concerns for applying BIC to estimate the brain injury risks for head impacts different from the head impacts on which the BIC was developed.Social animals can improve their decisions by attending to those made by others. The benefit of this social information must be balanced against the costs of obtaining and processing it. Previous work has focused on rational agents that respond optimally to a sequence of prior decisions. However, full decision sequences are potentially costly to perceive and process. As such, animals may rely on simpler social information, which will affect the social behaviour they exhibit. Here, I derive the optimal policy for agents responding to simplified forms of social information. I show how the behaviour of agents attending to the aggregate number of previous choices differs from those attending to just the most recent prior decision, and I propose a hybrid strategy that provides a highly accurate approximation to the optimal policy with the full sequence. Finally, I analyse the evolutionary stability of each strategy, showing that the hybrid strategy dominates when cognitive costs are low but non-zero, while attending to the most recent decision is dominant when costs are high. These results show that agents can employ highly effective social decision-making rules without requiring unrealistic cognitive capacities, and indicate likely ecological variation in the social information different animals attend to.Achieving and maintaining high-level immunization coverage is the priority of the health-care delivery system. However, any delay in receiving the vaccine leaves youngsters inadequately protected. Timely vaccination has scarcely been reported and given little attention in developing nations like Ethiopia, which hinders effective interventions. Therefore, this study aimed to assess age-appropriate vaccination practice and associated factors among mothers of children aged less than one year in the pastoral community. A community-based cross-sectional study has conducted among 340 mothers/caregivers of children aged less than one year in Samara-logia city administration. A systematic random sampling technique was employed to identify and enroll mothers-child paired. The logistic regression analysis had done to identify the factors associated with age-appropriate vaccination practice. The statistical association had measured, and a p-value less then 0.05 was considered statistically significant. In this study, a total of 331 mothers/caregivers-child pairs participated with a response rate of 97.3%. The age-appropriate vaccination practice was 43.7% (95% CI, 38%, 49.5%). Mothers who had higher educational level (Adjusted odds ratio (AOR)) = AOR = 2.89, 95% CI (1.14, 7.3), antenatal care follow-up (AOR = 2.1, 95% CI (1.04, 4.1)), and had good knowledge on vaccination (AOR = 3.1, 95% CI (1.4, 6.78)) were associated with increased odds of age-appropriate vaccination practice.
Traditionally, the root of
Nakai (Umbelliferae), has long been used to treat ischaemic diseases and is considered safe in humans.
To investigate the neuroprotective effects of a methanol extract of
root (AGmex) on the middle cerebral artery occlusion (MCAO)-induced brain injury in mice, and the underlying mechanisms.
Two hours of transient MCAO (tMCAO) was induced in C57BL/6 mice (MCAO control group and AGmex groups), AGmex was administered to the AGmex group at 300-3,000 mg/kg bw at 1, 1, and 24 h before tMCAO or at 1000 mg/kg bw at 1 h before and after tMCAO. Infarction volumes, tissue staining, and western blotting were used to investigate the mechanism underlying the neuroprotective effects of AGmex.
The median effective dose (ED
) could not be measured because the AGmex treatment did not reduce the infarction volume caused by 2 h of tMCAO to within 50%; however, pre-treatment with AGmex twice at 1,000 mg/kg bw before tMCAO significantly reduced the infarction volumes. The proteins related to cell growth, differentiation, and death were upregulated by this treatment, and the major recovery mechanisms appeared to involve the attenuation of the mitochondrial function of Bcl-2/Bax and activation of the PI3K/AKT/mTOR and MAPK signalling pathways in ischaemic neurons.
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