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Prey refuge from predators can play an important role in stabilising an ecological system by reducing interactions between species, while Allee effects can arise from a range of biological phenomena, such as anti-predator vigilance, genetic trends and feeding deficiencies. We develop a predator–prey model that combines these phenomena, considering variable prey refuge with additive Allee effect on the prey species, with a Holling type II response function for the prey growth function. We use the predator and prey nullclines to determine the existence and stability of interior equilibria. We also investigate all possible local and global bifurcations that the system could undergo, showing that prey refuge and a strong Allee effect can lead to saddle-node bifurcations, Hopf bifurcations or Bogdanov–Takens bifurcation. We have investigated the appearance of Hopf bifurcations in a neighborhood of the unique interior equilibrium point of the dynamical system. The rich behaviour of the dynamics suggests that both prey refuge and a strong Allee affect are important factors in ecological complexity.

This study compares the sociopragmatic competence demonstrated by adolescents with hearing loss to that of adolescents with typical hearing raised in a bilingual Spanish-English context. We examine the speech act of refusals made by sixteen subjects, 12–19 years old, from the city of Miami, Florida. Eight of them were typically hearing. The other eight were diagnosed with bilateral severe to profound prelingual hearing loss before 2 ½ years of age and used spoken language as their primary method of communication. Our main objectives were: 1) to describe the preferred politeness strategies of these individuals while performing refusals in English and in Spanish; 2) to assess the degree of (in)directness with an interlocutor depending on power and distance; and 3) to determine if some pragmatic transfer occurs from one language to the other. The pragmatic abilities of both groups appeared higher in English than in Spanish, but it cannot be concluded that adolescents with hearing loss lack pragmatic abilities in either language.

The large-scale infection of COVID-19 has led to a significant impact on lives and economies around the world and has had considerable impact on global public health. Social distancing, mask wearing and contact tracing have contributed to containing or at least mitigating the outbreak, but how public awareness influences the effectiveness and efficiency of such approaches remains unclear. In this study, we developed a discrete compartment dynamic model to mimic and explore how media reporting and the strengthening containment strategies can help curb the spread of COVID-19 using Shaanxi Province, China, as a case study. The targeted model is parameterized based on multi-source data, including the cumulative number of confirmed cases, recovered individuals, the daily number of media-reporting items and the imported cases from the rest of China outside Shaanxi from January 23 to April 11, 2020. We carried out a sensitivity analysis to investigate the effect of media reporting and imported cases on transmission. The results revealed that reducing the intensity of media reporting, which would result in a significant increasing of the contact rate and a sizable decreasing of the contact-tracing rate, could aggravate the outbreak severity by increasing the cumulative number of confirmed cases. It also demonstrated that diminishing the imported cases could alleviate the outbreak severity by reducing the length of the epidemic and the final size of the confirmed cases; conversely, delaying implementation of lockdown strategies could prolong the length of the epidemic and magnify the final size. These findings suggest that strengthening media coverage and timely implementing of lockdown measures can significantly reduce infection.

PPFIA3encodes the Protein-Tyrosine Phosphatase, Receptor-Type, F Polypeptide-Interacting Protein Alpha-3 (PPFIA3), which is a member of the LAR protein-tyrosine phosphatase-interacting protein (liprin) family involved in synaptic vesicle transport and presynaptic active zone assembly. The protein structure and function are well conserved in both invertebrates and vertebrates, but human diseases related to PPFIA3 dysfunction are not yet known. Here, we report 14 individuals with rare mono-allelicPPFIA3variants presenting with features including developmental delay, intellectual disability, hypotonia, autism, and epilepsy. To determine the pathogenicity ofPPFIA3variantsin vivo, we generated transgenic fruit flies expressing either human PPFIA3 wildtype (WT) or variant protein using GAL4-UAS targeted gene expression systems. Ubiquitous expression with Actin-GAL4 showed that thePPFIA3variants had variable penetrance of pupal lethality, eclosion defects, and anatomical leg defects. Neuronal expression with elav-GAL4 showed that thePPFIA3variants had seizure-like behaviors, motor defects, and bouton loss at the 3rdinstar larval neuromuscular junction (NMJ). Altogether, in the fly overexpression assays, we found that thePPFIA3variants in the N-terminal coiled coil domain exhibited stronger phenotypes compared to those in the C-terminal region. In the loss-of-function fly assay, we show that the homozygous loss of flyLiprin-α leads to embryonic lethality. This lethality is partially rescued by the expression of humanPPFIA3WT, suggesting human PPFIA3 protein function is partially conserved in the fly. However, thePPFIA3variants failed to rescue lethality. Altogether, the human and fruit fly data reveal that the rarePPFIA3variants are dominant negative loss-of-function alleles that perturb multiple developmental processes and synapse formation.