Tel Aviv University

About: Tel Aviv University is a education organization based out in Tel Aviv, Israel. It is known for research contribution in the topics: Population & Medicine. The organization has 47791 authors who have published 115959 publications receiving 3904391 citations. The organization is also known as: TAU & Universiṭat Tel-Aviv.

Y chromosome sequence variation and the history of human populations

Abstract: Binary polymorphisms associated with the non-recombining region of the human Y chromosome (NRY) preserve the paternal genetic legacy of our species that has persisted to the present, permitting inference of human evolution, population affinity and demographic history 1 . We used denaturing highperformance liquid chromatography (DHPLC; ref. 2) to identify 160 of the 166 bi-allelic and 1 tri-allelic site that formed a parsimonious genealogy of 116 haplotypes, several of which display distinct population affinities based on the analysis of 1062 globally representative individuals. A minority of contemporary East Africans and Khoisan represent the descendants of the most ancestral patrilineages of anatomically modern humans that left Africa between 35,000 and 89,000 years ago.

Freezing of gait: Moving forward on a mysterious clinical phenomenon

Abstract: Freezing of gait (FoG) is a unique and disabling clinical phenomenon characterised by brief episodes of inability to step or by extremely short steps that typically occur on initiating gait or on turning while walking. Patients with FoG, which is a feature of parkinsonian syndromes, show variability in gait metrics between FoG episodes and a substantial reduction in step length with frequent trembling of the legs during FoG episodes. Physiological, functional imaging, and clinical-pathological studies point to disturbances in frontal cortical regions, the basal ganglia, and the midbrain locomotor region as the probable origins of FoG. Medications, deep brain stimulation, and rehabilitation techniques can alleviate symptoms of FoG in some patients, but these treatments lack efficacy in patients with advanced FoG. A better understanding of the phenomenon is needed to aid the development of effective therapeutic strategies.

Construal Levels and Self-Control

Abstract: The authors propose that self-control involves making decisions and behaving in a manner consistent with high-level versus low-level construals of a situation. Activation of high-level construals (which capture global, superordinate, primary features of an event) should lead to greater self-control than activation of low-level construals (which capture local, subordinate, secondary features). In 6 experiments using 3 different techniques, the authors manipulated construal levels and assessed their effects on self-control and underlying psychological processes. High-level construals led to decreased preferences for immediate over delayed outcomes, greater physical endurance, stronger intentions to exert self-control, and less positive evaluations of temptations that undermine self-control. These results support a construal-level analysis of self-control.

Color-coding

Abstract: We describe a novel randomized method, the method of color-coding for finding simple paths and cycles of a specified length k, and other small subgraphs, within a given graph G = (V,E). The randomized algorithms obtained using this method can be derandomized using families of perfect hash functions. Using the color-coding method we obtain, in particular, the following new results: • For every fixed k, if a graph G = (V,E) contains a simple cycle of size exactly k, then such a cycle can be found in either O(V ) expected time or O(V ω log V ) worst-case time, where ω < 2.376 is the exponent of matrix multiplication. (Here and in what follows we use V and E instead of |V | and |E| whenever no confusion may arise.) • For every fixed k, if a planar graph G = (V,E) contains a simple cycle of size exactly k, then such a cycle can be found in either O(V ) expected time or O(V log V ) worst-case time. The same algorithm applies, in fact, not only to planar graphs, but to any minor closed family of graphs which is not the family of all graphs. • If a graph G = (V,E) contains a subgraph isomorphic to a bounded tree-width graph H = (VH , EH) where |VH | = O(log V ), then such a copy of H can be found in polynomial time. This was not previously known even if H were just a path of length O(log V ). These results improve upon previous results of many authors. The third result resolves in the affirmative a conjecture of Papadimitriou and Yannakakis that the LOG PATH problem is in P. We can show that it is even in NC.