Root growth and signalling: the role of calcium channels

Roots acquire calcium not only as a macronutrient but also to serve as a second messenger in signalling and a component of exocytosis for growth. Plasma membrane channels are sufficient to deliver calcium from the apoplast to the cytosol to enable its participation in nutrition, adaptation and development. The identity and regulatory mechanisms of these channels are central to our understanding of how calcium manages to “do it all”. By studying Arabidopsis roots, it’s been possible to discover plasma membrane channels involved in growth and signalling, allied to the finding that plants utilise the most damaging reactive oxygen species, the hydroxyl radical, constructively. As an overarching regulator, roots utilise extracellular purine nucleotides in a calcium-based signalling system that differs substantially from that of animals.Universidad de Málaga. Campus Internacional Andalucía Tec

The Hydrodynamics of Active Systems

This is a series of four lectures presented at the 2015 Enrico Fermi summer school in Varenna. The aim of the lectures is to give an introduction to the hydrodynamics of active matter concentrating on low Reynolds number examples such as cells and molecular motors. Lecture 1 introduces the hydrodynamics of single active particles, covering the Stokes equation and the Scallop Theorem, and stressing the link between autonomous activity and the dipolar symmetry of the far flow field. In lecture 2 I discuss applications of this mathematics to the behaviour of microswimmers at surfaces and in external flows, and describe our current understanding of how swimmers stir the surrounding fluid. Lecture 3 concentrates on the collective behaviour of active particles, modelled as an active nematic. I write down the equations of motion and motivate the form of the active stress. The resulting hydrodynamic instability leads to a state termed active turbulence characterised by strong jets and vortices in the flow field and the continual creation and annihilation of pairs of topological defects. Lecture 4 compares simulations of active turbulence to experiments on suspensions of microtubules and molecular motors. I introduce lyotropic active nematics and discuss active anchoring at interfaces.Comment: Lecture Notes, 2015 Enrico Fermi Summer School on Soft Matter Self-Assembly, Vienn

Under the Wing of a Creature of the Night

Magnificent in its sheer power and beauty, this owl wing has a wingspan of 18 inches and measures 10 inches from the shoulder bone to the secondary feathers. Wings such as the one displayed play a vital role in the lifestyle of owls and other hunting birds who fulfill their dietary requirements through stealthy foraging in the dark of the night. Being predatory animals, an owl depends upon its wings as a weapon, equipping it with an arsenal worthy of any hunter. Because of their composition of downy feathers, soft fringes, and comb-like primary feathers, these light appendages create less audible sound waves through air, giving an owl the advantage of nearly silent flight. [excerpt

Rocky Horror: A Study in Shadows and Flight

“Rocky Horror: A Study in Shadows and Flight” is a creative nonfiction piece that analyzes the infamous legacy left by the cult classic, The Rocky Horror Picture Show. As a first-year in college, the speaker strings together a series of vignettes from different encounters with the film in her life, from her first midnight showing to her first performance as Columbia in a live production. In a few pages, this piece examines the meaning of identity and freedom as the speaker works through repulsion, rebellion, and all things Rocky

Spoken word classification in children and adults

Purpose: Preschool children often have difficulties in word classification, despite good speech perception and production. Some researchers suggest they represent words using phonetic features rather than phonemes. We examine whether there is a progression from feature based to phoneme based processing across age groups, and whether responses are consistent across tasks and stimuli. Method: In Study 1, 120 3 to 5 year old children completed three tasks assessing use of phonetic features in classification, with an additional 58 older children completing one of the three tasks. In Study 2, all of the children, together with an additional adult sample, completed a nonword learning task. Results: In all four tasks, children classified words sharing phonemes as similar. In addition, children regarded words as similar if they shared manner of articulation, particularly word-finally. Adults also showed this sensitivity to manner, but across the tasks there was a pattern of increasing use of phonemic information with age. Conclusions: Children tend to classify words as similar if they share phonemes or share manner of articulation word finally. Use of phonemic information becomes more common with age. These findings are in line with the theory that phonological representations become more detailed in the preschool years

Introductions

An introduction to the Symposium and an introduction to Blockchain technology in preparation for the topics of the rest of the symposium

Problems and Management Decisions of New Bulgarian Farmers

The paper presents the organisational changes in agriculture and makes evaluation of management decisions and basic problems of Bulgarian family farms, cooperatives and partnerships. The paper is based on the field research work of the authors on the project “Comparative analysis of functioning and management of private production structures in agrarian sector” in Bulgaria (1999-2000), granted by the research program of the University for National and World Economy - Sofia. In first part of the paper farm structure is treated in two aspects: management organisation (legal form) and farm size. Independently of relatively small territory in Bulgaria existing and functioning together the both European farm models. In Northeast Bulgaria predominates the large size farm with typical characterizations for “Northern model”. The “Southern model” predominates not only in the mountain and semi mountain areas. Very small and small holdings are functioning in everyone villages. The analysis in second part is on data of survey in several regions in country. There are 50 family farms and 55 agricultural production cooperatives with typical production specialization and farm size. The survey includes three groups of questions about production resources, management decisions, organizational problems, production results and others. The last part of paper shows tendencies and alternatives for improvement of the management adaptivity and competitiveness of the newly formed organisations.Farm Management, Productivity Analysis,