Statistics of statisticians: Critical mass of statistics and operational research groups in the UK

Using a recently developed model, inspired by mean field theory in statistical physics, and data from the UK's Research Assessment Exercise, we analyse the relationship between the quality of statistics and operational research groups and the quantity researchers in them. Similar to other academic disciplines, we provide evidence for a linear dependency of quality on quantity up to an upper critical mass, which is interpreted as the average maximum number of colleagues with whom a researcher can communicate meaningfully within a research group. The model also predicts a lower critical mass, which research groups should strive to achieve to avoid extinction. For statistics and operational research, the lower critical mass is estimated to be 9 $\pm$ 3. The upper critical mass, beyond which research quality does not significantly depend on group size, is about twice this value

El yugo doble

Contrariamente á la opinión admitida por la generalidad, el buey da con la misma fatiga y por consecuencia con el mismo consumo de materias alimenticías, una tracción más considerable con una pechera apoyada en sus espaldas que con un arnés apoyado en su cabeza. Es suficiente examinar un esqueleto de bovídeo para comprender que el esfuerzo proveniente del bípedo posterior (el bípedo anterior no sirve sino para soportar la mayor parte del peso del animal) se efectúa en el caso de la pechera, por las vértebras lumbares y dorsales mientras que, con el atalaje de la cabeza, la transmisión de la tracción debe pasar desde la sutura sacro-lliaca, por las vértebras lumbares dorsales y cervicales, al atlas, para comunicarse al occipital y á los frontales finalmente. Aun cuando el cuello del bovídeo sea corto, comparándolo con el del equídeo, sus vértebras muy articuaadas no pueden jamás transmitir la totalidad de los esfuerzos ejercidos sobre la cruz y la espalda.Facultad de Ciencias Agrarias y Forestale

Compresión de los forrages

La compresión de los forrages es una operación que puede ser tentada con fines diferentes. A) En el caso más simple, se busca suprimir el amontonamiento ordinario, asegurar la conservación del producto, disminuir las dimensiones del local necesario para el almacenado (y por consiguiente el precio del alquiler) y por último alejar las alteraciones por incendio. B) Se puede buscar, por la compresión, disminuir los gastos de transporte por ferrocarriles o por buques, y se pueden distinguir las materias destinadas a la alimentación de los animales de las reservadas a los usos industriales.Facultad de Ciencias Agrarias y Forestale

Neidharts tanzwütige Mütter und Töchter : Materialien für die Sekundarstufe II

Der zweite Band der Reihe MimaSch bietet nach einem Unterrichtsentwurf für die Grundschule nun auch Materialien für den Einsatz mittelalterlicher Sprache und Literatur im Deutschunterricht in der Sekundarstufe II (10.–12. Klasse). Die hier enthaltenen Materialien bilden eine optimierte, für die Durchführung im Unterricht flexibel konzipierte Unterrichtssequenz im Umfang von vier bis fünf Doppelstunden, die vorab an mehreren Gymnasien erprobt und weiterentwickelt wurde. In der Sequenz erfolgt eine Auseinandersetzung mit den sog. ‚Mutter-Tochter-Dialogliedern‘ des mittelalterlichen Lieddichters Neidhart. Verbunden mit handlungs- und produktionsorientierten Verfahren sollen die Schülerinnen und Schüler abschließend ein psychologisches Gutachten erstellen. Damit werden an einem andersartigen Unterrichtsgegenstand (mittelalterliche Literatur) und einem zumindest teilweise vertrauten Inhalt (Generationenkonflikt Mutter-Tochter) verschiedene in den Lehrplänen der Oberstufe geforderte Kompetenzen aufgebaut bzw. gefestigt, die Abiturrelevanz besitzen. Das einführende Kapitel liefert den Lehrkräften neben einer thematischen Hinführung und der Verortung der Inhalte im Lehrplan auch einen Umsetzungsvorschlag für die Handhabung der Materialien und die Durchführung der Sequenz im Deutschunterricht der gymnasialen Oberstufe

Academic research groups: evaluation of their quality and quality of their evaluation

In recent years, evaluation of the quality of academic research has become an increasingly important and influential business. It determines, often to a large extent, the amount of research funding flowing into universities and similar institutes from governmental agencies and it impacts upon academic careers. Policy makers are becoming increasingly reliant upon, and influenced by, the outcomes of such evaluations. In response, university managers are increasingly attracted to simple indicators as guides to the dynamics of the positions of their various institutions in league tables. However, these league tables are frequently drawn up by inexpert bodies such as newspapers and magazines, using rather arbitrary measures and criteria. Terms such as "critical mass' and "metrics" are often bandied about without proper understanding of what they actually mean. Rather than accepting the rise and fall of universities, departments and individuals on a turbulent sea of arbitrary measures, we suggest it is incumbent upon the scientific community itself to clarify their nature. Here we report on recent attempts to do that by properly defining critical mass and showing how group size influences research quality. We also examine currently predominant metrics and show that these fail as reliable indicators of group research quality.Comment: Presented at the International Conference on Computer Simulation in Physics and Beyond in Moscow, 2015. The Proceedings will appear in Journal of Physics: Conference Series (JPCS

The role for the exocyst complex subunits Exo70B2 and Exo70H1 in the plant–pathogen interaction

Recently, the octameric vesicle-tethering complex exocyst was found in plants and its importance for Arabidopsis morphogenesis was demonstrated. Exo70 exocyst subunits in plants, unlike in yeasts and mammals, are represented by a multigene family, comprising 23 members in Arabidopsis. For Exo70B2 and Exo70H1 paralogues, transcriptional up-regulation was confirmed on treatment with an elicitor peptide, elf18, derived from the bacterial elongation factor. Their ability to participate in the exocyst complex formation was inferred by the interaction of both the Exo70s with several other exocyst subunits using the yeast two-hybrid system. Arabidopsis plants mutated in these two genes were used to analyse their local reaction upon inoculation with Pseudomonas syringae pv. maculicola and the fungal pathogen Blumeria graminis f. sp. hordei. The Pseudomonas sensitivity test revealed enhanced susceptibility for the two exo70B2 and one H1 mutant lines. After Blumeria inoculation, an increase in the proportion of abnormal papilla formation, with an unusual wide halo made of vesicle-like structures, was found in exo70B2 mutants. Intracellular localization of both Exo70 proteins was studied following a GFP fusion assay and Agrobacterium-mediated transient expression of the constructs in Nicotiana benthamiana leaf epidermis. GFP-Exo70H1 localizes in the vesicle-like structures, while GFP-Exo70B2 is localized mainly in the cytoplasm. It is concluded that both Exo70B2 and Exo70H1 are involved in the response to pathogens, with Exo70B2 having a more important role in cell wall apposition formation related to plant defence

Sleep deprivation impairs and caffeine enhances my performance, but not always our performance: how acting in a group can change the effects of impairments and enhancements

What effects do factors that impair or enhance performance in individuals have when these individuals act in groups? We provide a framework, called the GIE ("Effects of Grouping on Impairments and Enhancements”) framework, for investigating this question. As prominent examples for individual-level impairments and enhancements, we discuss sleep deprivation and caffeine. Based on previous research, we derive hypotheses on how they influence performance in groups, specifically process gains and losses in motivation, individual capability, and coordination. We conclude that the effect an impairment or enhancement has on individual-level performance is not necessarily mirrored in group performance: grouping can help or hurt. We provide recommendations on how to estimate empirically the effects individual-level performance impairments and enhancements have in groups. By comparing sleep deprivation to stress and caffeine to pharmacological cognitive enhancement, we illustrate that we cannot readily generalize from group results on one impairment or enhancement to another, even if they have similar effects on individual-level performance

Nash Equilibria in Multi-Agent Motor Interactions

Social interactions in classic cognitive games like the ultimatum game or the prisoner's dilemma typically lead to Nash equilibria when multiple competitive decision makers with perfect knowledge select optimal strategies. However, in evolutionary game theory it has been shown that Nash equilibria can also arise as attractors in dynamical systems that can describe, for example, the population dynamics of microorganisms. Similar to such evolutionary dynamics, we find that Nash equilibria arise naturally in motor interactions in which players vie for control and try to minimize effort. When confronted with sensorimotor interaction tasks that correspond to the classical prisoner's dilemma and the rope-pulling game, two-player motor interactions led predominantly to Nash solutions. In contrast, when a single player took both roles, playing the sensorimotor game bimanually, cooperative solutions were found. Our methodology opens up a new avenue for the study of human motor interactions within a game theoretic framework, suggesting that the coupling of motor systems can lead to game theoretic solutions