The effects of Facebook and Instagram on the 2020 election: A deactivation experiment.

We study the effect of Facebook and Instagram access on political beliefs, attitudes, and behavior by randomizing a subset of 19,857 Facebook users and 15,585 Instagram users to deactivate their accounts for 6 wk before the 2020 U.S. election.

Digging deeper into colonial palaeontological practices in modern day Mexico and Brazil.

Scientific practices stemming from colonialism, whereby middle- and low-income countries supply data for high-income countries and the contributions of local expertise are devalued, are still prevalent today in the field of palaeontology. In response to these unjust practices, countries such as Mexico and Brazil adopted protective laws and regulations during the twentieth century to preserve their palaeontological heritage. However, scientific colonialism is still reflected in many publications describing fossil specimens recovered from these countries.

Platelets modulate CD4 T-cell function in COVID-19 through a PD-L1 dependent mechanism.

Severe COVID-19 is associated with a systemic inflammatory response and progressive CD4 T-cell lymphopenia and dysfunction. We evaluated whether platelets might contribute to CD4 T-cell dysfunction in COVID-19. We observed a high frequency of CD4 T cell-platelet aggregates in COVID-19 inpatients that inversely correlated with lymphocyte counts.

Sinus pericranii, petrosquamosal sinus and extracranial sigmoid sinus: Anatomical variations to consider during a retroauricular approach.

Lateral and sigmoid sinus malformations are uncommon and dangerous anatomical variations that surgeons may encounter when performing a retroauricular approach. We report three cases of rare temporal bone venous sinus anomalies seen in patients who underwent cochlear implant surgery. The first patient had a diagnosis of CHARGE syndrome and presented a bilateral persistent petrosquamosal sinus with sigmoid sinus agenesis, which made mastoidectomy for cochlear implantation difficult.

Tiarajudens eccentricus and Anomocephalus africanus, two bizarre anomodonts (Synapsida, Therapsida) with dental occlusion from the Permian of Gondwana.

Anomodontia was a highly successful tetrapod clade during the Permian and the Triassic. New morphological information regarding two bizarre basal anomodonts is provided and their palaeoecological significance is explored. The osteology of the recently discovered Tiarajudens eccentricus Cisneros et al.

Carnivorous dinocephalian from the Middle Permian of Brazil and tetrapod dispersal in Pangaea.

The medial Permian (~270-260 Ma: Guadalupian) was a time of important tetrapod faunal changes, in particular reflecting a turnover from pelycosaurian- to therapsid-grade synapsids. Until now, most knowledge on tetrapod distribution during the medial Permian has come from fossils found in the South African Karoo and the Russian Platform, whereas other areas of Pangaea are still poorly known. We present evidence for the presence of a terrestrial carnivorous vertebrate from the Middle Permian of South America based on a complete skull.

Dental occlusion in a 260-million-year-old therapsid with saber canines from the Permian of Brazil.

Anomodonts, a group of herbivorous therapsid "mammal-like reptiles," were the most abundant tetrapods of the Permian. We present a basal anomodont from South America, a new taxon that has transversally expanded palatal teeth and long saber canines. The function of the saber teeth is unknown, but probable uses include deterring attack from predators and intraspecific display or combat.

Spondarthritis in the triassic.

Background: The evidence of several forms of arthritis has been well documented in the fossil record. However, for pre-Cenozoic vertebrates, especially regarding reptiles, this record is rather scarce. In this work we present a case report of spondarthritis found in a vertebral series that belonged to a carnivorous archosaurian reptile from the Lower Triassic (∼245 million years old) of the South African Karoo.