نتایج جستجو برای: ancient

تعداد نتایج: 38123  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2016
Priya Moorjani Sriram Sankararaman Qiaomei Fu Molly Przeworski Nick Patterson David Reich

The study of human evolution has been revolutionized by inferences from ancient DNA analyses. Key to these studies is the reliable estimation of the age of ancient specimens. High-resolution age estimates can often be obtained using radiocarbon dating, and, while precise and powerful, this method has some biases, making it of interest to directly use genetic data to infer a date for samples tha...

2012
Susanna Sawyer Johannes Krause Katerina Guschanski Vincent Savolainen Svante Pääbo

DNA that survives in museum specimens, bones and other tissues recovered by archaeologists is invariably fragmented and chemically modified. The extent to which such modifications accumulate over time is largely unknown but could potentially be used to differentiate between endogenous old DNA and present-day DNA contaminating specimens and experiments. Here we examine mitochondrial DNA sequence...

2006
Alemayehu Geda

Much of the macroeconomic analysis in Ethiopia is hardly linked to the country’s pioneer development thinkers. The latter, however, articulated the Ethiopian development problems and what should be the appropriate policy direction to address them nearly a century ago. This articulated development thinkers of the early 20 th century Ethiopia had captured the imagination of prominent Ethiopian hi...

Journal: :Des. Codes Cryptography 2012
Maria Christopoulou Theodoulos Garefalakis Daniel Panario David Thomson

Optimal normal bases are special cases of the so-called Gauss periods (Disquisitiones Arithmeticae, Articles 343-366); in particular, optimal normal bases are Gauss periods of type (n,1) for any characteristic and type (n,2) for characteristic 2. We present the multiplication tables and complexities of Gauss periods of type (n, t) for all n and t = 3,4,5 over any finite field and give a slightl...

2010
Annika Lindskog

This paper contributes to the knowledge about how educational investments are allocated across siblings within the household. More specifically I focus on investigating whether there are signs of diversification, formal schooling being a risky investment. The data used is unusual in that it includes the head of household’s risk preferences in addition to school-related and other information. Th...

2011
Iris Reinhartz-Berger Arava Tsoury

Core assets are reusable artifacts built to be used in different software products in the same family. As such, core assets need to capture both commonality that exists and variability that is allowed in the product family (line). These assets are later utilized for guiding the creation of particular valid products in the family. Feature-oriented and UML-based methods have been proposed for mod...

Journal: :Trends in ecology & evolution 2016
David Gokhman Eran Meshorer Liran Carmel

Recent years have witnessed the rise of ancient DNA (aDNA) technology, allowing comparative genomics to be carried out at unprecedented time resolution. While it is relatively straightforward to use aDNA to identify recent genomic changes, it is much less clear how to utilize it to study changes in epigenetic regulation. Here we review recent works demonstrating that highly degraded aDNA still ...

2011
DIMITRIS KOUKOULOPOULOS

Motivated by the Erdős multiplication table problem we study the following question: Given numbers N1, . . . , Nk+1, how many distinct products of the form n1 · · ·nk+1 with 1 ≤ ni ≤ Ni for i ∈ {1, . . . , k + 1} are there? Call Ak+1(N1, . . . , Nk+1) the quantity in question. Ford established the order of magnitude of A2(N1, N2) and the author of Ak+1(N, . . . , N) for all k ≥ 2. In the presen...

2000
Anthony Bebbington

Contemporary debates on the rural sector in Latin America have led many to question the future viability of peasant livelihoods in the Andes. The paper first discusses certain limitations in these discussions of peasant viability. Firstly, they conflate agrarian with rural livelihoods, thus deflecting attention from the myriad transitions that have occurred in the ways through which people make...

Journal: :Fertility and sterility 2012
Camran Nezhat Farr Nezhat Ceana Nezhat

E ver since Vincent Knapp published his 1999 article ‘‘How old is Endometriosis?’’ (1), there seems to have been renewed interest in identifying just when endometriosis was discovered as a distinct disease entity. While the history of endometriosis subsequent to its 1860 microscopic unveiling by Karl von Rokitansky has been well-studied, its story leading up to that moment has remained largely ...

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