Search Results (3)

Among the different models that have been proposed to explain the origin of avian flight
from terrestrial predators, the cursorial and arboreal hypotheses remain the most discussed.
However, the fossil data at hand show that, taken separately, both theories have significant
limitations in explaining the origin of flight in bird lineage. Here, we describe an aerodynamics
principle that fills in the gaps between those apparently contradictory models. The upslope wind in
mountain areas and strong wind in plains provided the meteorological conditions allowing
feathered paravians to glide. The results suggest that smaller, feathered paravians could be lifted to
glide down to trees on mountain slopes or even to glide up to high trees in plain areas when meeting
a strong airflow as they were pursuing a prey or escaping from a predator. The development of
more aerodynamical limb feathers was a key factor for gliding down the trees because of the
dependency of the resultant force on the surface area of a paravian’s body. Later in the evolution
process, paravians learned to change the orientation of their wings to gain higher lifts. The proposed
principle and the results obtained in the present research help to better estimate the aerodynamic
behavior of extinct species and will also help to design an efficient and beneficial system for future
flying robots. Full article

A cursory look at any textbook image of DNA replication might suggest that the complex machine that is the replisome runs smoothly along the chromosomal DNA. However, many DNA sequences can adopt non-B form secondary structures and these have the potential to impede progression of the replisome. A picture is emerging in which the maintenance of processive DNA replication requires the action of a significant number of additional proteins beyond the core replisome to resolve secondary structures in the DNA template. By ensuring that DNA synthesis remains closely coupled to DNA unwinding by the replicative helicase, these factors prevent impediments to the replisome from causing genetic and epigenetic instability. This review considers the circumstances in which DNA forms secondary structures, the potential responses of the eukaryotic replisome to these impediments in the light of recent advances in our understanding of its structure and operation and the mechanisms cells deploy to remove secondary structure from the DNA. To illustrate the principles involved, we focus on one of the best understood DNA secondary structures, G quadruplexes (G4s), and on the helicases that promote their resolution. Full article

A cursory look at Indian prime-time news tells us much about the tone and tenor of the people associated with it. Exaggerations, hyperbole, and tempers run wild, and news anchors flail in theatrical rage. News channels and news editors display their ideological affiliations subliminally. These affiliations—a factor of personal political stances, funding bodies, and investors—lead to partisan bias in the framing of news and, in some cases, can easily translate into racial prejudice. In this paper, I examine news coverage related to Muslims in India. I study the coverage of two issues specifically—love jihad and triple talaq—in prime-time English news of two channels: Times Now and Republic TV. Love jihad is a term used to describe alleged campaigns carried out by Muslim men targeting non-Muslim women for conversion to Islam by feigning love. Triple talaq is a form of divorce that has been interpreted to allow Muslim men to legally divorce their wives by stating the word “talaq” three times. My analysis of the content, tone, and tenor of their coverage shows that these channels propagate associations between Islam and backwardness, ignorance, and violence through consistent employment of the following tropes: “Muslim women need to be saved from Muslim men”; “Hindu women need to be saved from Muslim men”; and, “Muslims are not fully Indian—they are anti-national”. I place this study of news media within the current political climate in India and briefly touch on the conversations it guides and provokes. This is a first step in detailing a problem. It is also a call for further analysis on this subject to examine and evaluate if and how discourse manipulates public conversations and policy decisions. Full article