The power of teams that disagree:team formation in large action spaces

Recent work has shown that diverse teams can outperform a uniform team made of copies of the best agent. However, there are fundamental questions that were never asked before. When should we use diverse or uniform teams? How does the performance change as the action space or the teams get larger? Hence, we present a new model of diversity, where we prove that the performance of a diverse team improves as the size of the action space increases. Moreover, we show that the performance converges exponentially fast to the optimal one as we increase the number of agents. We present synthetic experiments that give further insights: even though a diverse team outperforms a uniform team when the size of the action space increases, the uniform team will eventually again play better than the diverse team for a large enough action space. We verify our predictions in a system of Go playing agents, where a diverse team improves in performance as the board size increases, and eventually overcomes a uniform team

What best animal science teachers do

Great teachers have the extraordinary ability to inspire and motivate even those students who resist learning. The top educators are knowledgeable not only about the content of the course they are teaching but also of the information, literature, and practice of instructional delivery to their audience. Many exemplary educators have been profiled and studied; however, there is a paucity of information pertaining to how the top animal science teachers teach. The objective of this study was to identify and describe characteristics of award-winning animal science teachers. The inclusion criterion for selecting faculty was being bestowed an excellence in teaching award through their professional organization. Each teacher answered a series of questions about themselves, their students, and the class being taught. Lecture was captured using a digital all-inclusive camera and later analyzed for pedagogical trends and instructor–student interactions. Despite a variety of topics being taught by award-winning teachers, there were multiple trends emerging from their classrooms. Common events included reviewing highlights of previous lectures, distributing something to students, posing questions during class, and calling on students by name. Each teacher taught differently, but they all understood their audience; they grasped the subject matter and most importantly, they valued students learning. Collectively, these findings can be utilized and applied by animal science teachers in their own environments in an attempt to foster improved student learning through excellent teaching

Genetic selection for ovulation rate and litter size in rabbits: estimation of genetic parameters and direct and correlated responses

The aim of this work was to estimate direct and correlated responses in survival rates in an experiment of selection for ovulation rate (OR) and litter size (LS) in a line of rabbits (OR_LS). From generation 0 to 6 (first selection period), females were selected only for second gestation OR estimated by laparoscopy. From generation 7 to 13 (second selection period), a 2-stage selection for OR and LS was performed. In stage 1, females having the greatest OR at second gestation were selected. In stage 2, selection was for the greatest average LS of the first 2 parities of the females selected in stage 1. Total selection pressure in females was about 30%. The line had approximately 17 males and 75 females per generation. Traits recorded were OR estimated as the number of corpora lutea in both ovaries, number of implanted embryos (IE) estimated as the number of implantation sites, LS estimated as total number of rabbits born recorded at each parity, embryo survival (ES) estimated as IE/OR, fetal survival (FS) estimated as LS/IE, and prenatal survival (PS) estimated as LS/OR. Data were analyzed using Bayesian methodology. The estimated heritabilities of LS, OR, IE, ES, FS, and PS were 0.07, 0.21, 0.10, 0.07, 0.12, and 0.16, respectively. Direct and correlated responses from this study were estimated in each period of selection as the difference between the average genetic values of last and first generation. In the first selection period, OR increased 1.36 ova, but no correlated response was observed in LS due to a decrease on FS. Correlated responses for IE, ES, FS, and PS in the first selection period were 1.11, 0.00, -0.04, and -0.01, respectively. After 7 generations of 2-stage selection for OR and LS, OR increased 1.0 ova and response in LS was 0.9 kits. Correlated responses for IE, ES, FS, and PS in the second selection period were 1.14, 0.02, 0.02, and 0.07, respectively. Two-stage selection for OR and LS can be a promising procedure to improve LS in rabbits.This study was supported by the Comision Interministerial de Ciencia y Tecnologia CICYT-AGL2005-07624-C03-01 CICYT-AGL2008-05514-C02-01 and by funds from Generalitat Valenciana research programme (Prometeo 2009/125).Ziadi, C.; Mocé Cervera, ML.; Laborda Vidal, P.; Blasco Mateu, A.; Santacreu Jerez, MA. (2013). Genetic selection for ovulation rate and litter size in rabbits: estimation of genetic parameters and direct and correlated responses. Journal of Animal Science. 91(7):3113-3120. https://doi.org/10.2527/jas.2012-6043S3113312091

The use of ions to control the charge and phase behavior of phospholipid membranes

The object of this thesis is to probe lipid-lipid interactions by examining the phase behavior of simple phosphatidic acid mixtures and “lipid raft” mixtures as a function of bulk pH and ion concentration, which are physiologically relevant control parameters. The results are organized in five chapters as follows. Chapter 1 provides an overview of biological lipids, their phase behavior and the parameters that affect it, and the electrostatics of charged surfaces. The materials and methods used in this work are presented in chapter 2. Chapters 3 and 4 explore the responses of PA/PC bilayers to simultaneous and sequential changes in KCl and CaCl2 concentrations, respectively, at different pH values. Finally, chapter 5 examines the miscibility transition of “lipid raft” mixtures as a function of bulk NaCl concentration