Giant Magnetoelectric Effect in a Multiferroic Material with a High Ferroelectric Transition Temperature

We present a unique example of giant magnetoelectric effect in a conventional multiferroic HoMnO3, where polarization is very large (~56 mC/m2) and the ferroelectric transition temperature is higher than the magnetic ordering temperature by an order. We attribute the uniqueness of the giant magnetoelectric effect to the ferroelectricity induced entirely by the off-center displacement of rare earth ions with large magnetic moments. This finding suggests a new avenue to design multiferroics with large polarization and higher ferroelectric transition temperature as well as large magnetoelectric effects

Are low-frequency songs sexually selected, and do they lose their potency in male–female interactions under noisy conditions?

ABSTRACT: We agree with Halfwerk et al. on the importance of including the receivers when studying the impact of anthropogenic noise. However, we find the conclusion that the use of lowfrequency song is sexually selected in great tits and that noisy conditions affect male–female communication premature for several reasons

Ingested insecticide to control Aedes aegypti: developing a novel dried attractive toxic sugar bait device for intra-domiciliary control

© 2020 The Author(s). Background: Illnesses transmitted by Aedes aegypti (Linnaeus, 1762) such as dengue, chikungunya and Zika comprise a considerable global burden; mosquito control is the primary public health tool to reduce disease transmission. Current interventions are inadequate and insecticide resistance threatens the effectiveness of these options. Dried attractive bait stations (DABS) are a novel mechanism to deliver insecticide to Ae. aegypti. The DABS are a high-contrast 28 inch2 surface coated with dried sugar-boric acid solution. Aedes aegypti are attracted to DABS by visual cues only, and the dried sugar solution elicits an ingestion response from Ae. aegypti landing on the surface. The study presents the development of the DABS and tests of their impact on Ae. aegypti mortality in the laboratory and a series of semi-field trials. Methods: We conducted multiple series of laboratory and semi-field trials to assess the survivability of Ae. aegypti mosquitoes exposed to the DABS. In the laboratory experiments, we assessed the lethality, the killing mechanism, and the shelf life of the device through controlled experiments. In the semi-field trials, we released laboratory-reared female Ae. aegypti into experimental houses typical of peri-urban tropical communities in South America in three trial series with six replicates each. Laboratory experiments were conducted in Quito, Ecuador, and semi-field experiments were conducted in Machala, Ecuador, an area with abundant wild populations of Ae. aegypti and endemic arboviral transmission. Results: In the laboratory, complete lethality was observed after 48 hours regardless of physiological status of the mosquito. The killing mechanism was determined to be through ingestion, as the boric acid disrupted the gut of the mosquito. In experimental houses, total mosquito mortality was greater in the treatment house for all series of experiments (P \u3c 0.0001). Conclusions: The DABS devices were effective at killing female Ae. aegypti under a variety of laboratory and semi-field conditions. DABS are a promising intervention for interdomiciliary control of Ae. aegypti and arboviral disease prevention.[Figure not available: see fulltext.

Energy decay for Timoshenko systems of memory type

AbstractLinear systems of Timoshenko type equations for beams including a memory term are studied. The exponential decay is proved for exponential kernels, while polynomial kernels are shown to lead to a polynomial decay. The optimality of the results is also investigated

Exponential stability of the wave equation with memory and time delay

We study the asymptotic behaviour of the wave equation with viscoelastic damping in presence of a time-delayed damping. We prove exponential stability if the amplitude of the time delay term is small enough

Corticosterone mediates the deleterious effect of medial septal inactivation on memory retrieval.

Manipulations of hippocampal afferents, as well as exposure to glucocorticoids, impair spatial memory retrieval. Objective: We evaluated the combined effect of medial septum inactivation with muscimol (GABAA agonist) and systemic corticosterone on spatial memory retrieval. Method: Forty-one male Wistar rats were divided into four groups: Vehicle intraseptal–Vehicle intraperitoneal (Veh–Veh, n = 10), Vehicle intraseptal–Corticosterone intraperitoneal (Veh–Cort, n = 11), Muscimol intraseptal–Vehicle intraperitoneal (Mus–Veh, n = 10), and Muscimol intraseptal–Corticosterone intraperitoneal (Mus–Cort, n = 10). Animals were trained in the Barnes maze and tested for retrieval 24 hr later. Results: Animals in the groups Veh–Cort, Veh–Mus, and Mus–Cort showed deficits in the retrieval test. However, the magnitude of this deficit was smaller in the animals with the combined treatment (Mus–Cort) than in those with only muscimol (d = 0.97 for escape latency; d = 0.95 for weighted nongoal explorations). Conclusions: We reproduced the effects of muscimol and corticosterone on memory retrieval. In addition, our data showed a reduced deficit in memory retrieval after the combined treatment suggesting a role of corticosterone on the attenuation of the effect of muscimol on hippocampal synaptic activity, possible through an underlying mechanism involving glutamatergic activity on the hippocampus. We describe for the first time the relation between the activity of the septo-hippocampal system and the rapid effects of corticosterone on memory retrieval. These results suggest a therapeutic potential of compounds derived from glucocorticoids as an alternative intervention to the traditional cholinergic therapies in the alleviation of the memory impairments observed on several pathologies related to hippocampal decline. (PsycInfo Database Record (c) 2021 APA, all rights reserved