Hyperbolic dimension of Julia sets of meromorphic maps with logarithmic tracts

We prove that for meromorphic maps with logarithmic tracts (e.g. entire or meromorphic maps with a finite number of poles from class $\mathcal B$), the Julia set contains a compact invariant hyperbolic Cantor set of Hausdorff dimension greater than 1. Hence, the hyperbolic dimension of the Julia set is greater than 1.Comment: 7 pages, 1 figur

Inhibitor-induced oxidation of the nucleus and cytosol in Arabidopsis thaliana: implications for organelle to nucleus retrograde signalling

Concepts of organelle-to-nucleus signalling pathways are largely based on genetic screens involving inhibitors of chloroplast and mitochondrial functions such as norflurazon, lincomycin (LINC), antimycin A (ANT) and salicylhydroxamic acid. These inhibitors favour enhanced cellular oxidation, but their precise effects on the cellular redox state are unknown. Using the in vivo reduction–oxidation (redox) reporter, roGFP2, inhibitor-induced changes in the glutathione redox potentials of the nuclei and cytosol were measured in Arabidopsis thaliana root, epidermal and stomatal guard cells, together with the expression of nuclear-encoded chloroplast and mitochondrial marker genes. All the chloroplast and mitochondrial inhibitors increased the degree of oxidation in the nuclei and cytosol. However, inhibitor-induced oxidation was less marked in stomatal guard cells than in epidermal or root cells. Moreover, LINC and ANT caused a greater oxidation of guard cell nuclei than the cytosol. Chloroplast and mitochondrial inhibitors significantly decreased the abundance of LHCA1 and LHCB1 transcripts. The levels of WHY1, WHY3 and LEA5 transcripts were increased in the presence of inhibitors. Chloroplast inhibitors decreased AOXA1 mRNA levels, while mitochondrial inhibitors had the opposite effect. Inhibitors that are used to characterize retrograde signalling pathways therefore have similar general effects on cellular redox state and gene expression

Microcontroller diagnostic system for evaluation of Stirling engine

Представлено систему вимірювання з мікроконтролером, за допомогою якої здійснюється діагностика та оцінюється ефективність роботи двигуна Стірлінга. В систему заімплементовано модель аналізу прототипу двигуна Стірлінга для знаходження оптимальних значень його основних робочих параметрів. Двигун Стірлінга оснащено сенсорами вимірювання температури за допомогою термопари з матеріалу залізо/константан типу Fe-CuNi/J і давачем тиску. Крім цього, запроектовано пристрій тестування із застосуванням 16-бітного контролера PIC18F для виконання аквізиції даних. У зв’язку з тим, що критично важливою частиною двигуна Стірлінга є регенератор, розроблено складну систему електронного керування регулювальних клапанів входу та виходу регенератора. Цю систему створено на основі сучасного мікроконтролера типу PIC24H корпорації Microchip. Систему обладнано оригінальною програмою мовою асемблер, яка покращує роботу двигуна Стірлінга та підвищує його продуктивність шляхом електронного керування клапанами. Електронна система виконує низку вимірювань на головному валу двигуна. Такими є вимірювання частоти обертання, використовуючи давач Холла. Сигнал давача Холла підлягає перетворенню з подальшим обробленням у процесорі PIC24H. Ці імпульси після перетворення в елементі Шотткі застосовуються для керування клапанами та синхронізації блока випередження й регулювання відкриття клапанів. Система також служить для перевірки потужності двигуна Стірлінга на підставі вимірювання обертового моменту на головному валу. Система характеризується розширеними функціональними можливостями, причому дані з 16-бітного мікроконтролера типу PIC24H обробляється в математичному модулі та, в подальшому, – у мікроконтролері типу ARM11. Система, окрім вимірювання потужності двигуна Стірлінга, відіграє істотну роль для дослідження характеристик двигуна. Тому побудовано випробувальний стенд, оснащений рядом процесорів для збору даних про частоту обертання і крутний момент. Ці дані використовуються для подальшого аналізу отриманих результатів науково-дослідних експериментів. Вал двигуна Стірлінга з’єднано зі спеціально сконструйованим вимірювальним пристроєм на базі електричного генератора, що дає змогу оцінювати динамічні параметри двигуна Стірлінга. Будова та структура випробувального стенда разом з електронною системою та електричним генератором буде предметом окремої статті.In this paper we present the microcontroller system for the diagnostics and evaluation of the Stirling engine performance. For this purpose the analysis model for the prototype engine has been developed to present the engine’s improved benchmarking results. The functioning of this engine has been analysed with the aim to find and optimize the main working parameters. To obtain this goal the Stirling engine has been equipped with different kinds of electronic sensors. A microcontroller testing circuit has been designed, which uses the acquisition of data from the data module

Nuclear and peroxisomal targeting of catalase

Catalase is a well-known component of the cellular antioxidant network, but there have been conflicting conclusions reached regarding the nature of its peroxisome targeting signal. It has also been reported that catalase can be hijacked to the nucleus by effector proteins of plant pathogens. Using a physiologically relevant system where native untagged catalase variants are expressed in a cat2-1 mutant background, the C terminal most 18 amino acids could be deleted without affecting activity, peroxisomal targeting or ability to complement multiple phenotypes of the cat2-1 mutant. In contrast, converting the native C terminal tripeptide PSI to the canonical PTS1 sequence ARL resulted in lower catalase specific activity. Localisation experiments using split superfolder green fluorescent protein revealed that catalase can be targeted to the nucleus in the absence of any pathogen effectors, and that C terminal tagging in combination with alterations of the native C terminus can interfere with nuclear localisation. These findings provide fundamental new insights into catalase targeting and pave the way for exploration of the mechanism of catalase targeting to the nucleus and its role in non-infected plants

Two-dimensional quantum interference contributions to the magnetoresistance of Nd{2-x}Ce{x}CuO{4-d} single crystals

The 2D weak localization effects at low temperatures T = (0.2-4.2)K have been investigated in nonsuperconducting sample Nd{1.88}Ce{0.12}CuO{4-d} and in the normal state of the superconducting sample Nd{1.82}Ce{0.18}CuO{4-d} for B>B_c2. The phase coherence time and the effective thickness $d$ of a conducting CuO_2 layer have been estimated by the fitting of 2D weak localization theory expressions to the magnetoresistivity data for the normal to plane and the in-plane magnetic fields.Comment: 5 pages, 4 postscript figure

What factors influence training opportunities for older workers? Three factorial surveys exploring the attitudes of HR professionals

The core research questions addressed in this paper are: what factors influence HR professionals in deciding whether to approve training proposals for older workers? What kind of training are they more likely to recommend for older employees and in which organizational contexts? We administered three factorial surveys to 66 HR professionals in Italy. Participants made specific training decisions based on profiles of hypothetical older workers. Multilevel analyses indicated that access to training decreases strongly with age, while highly-skilled older employees with low absenteeism rates are more likely to enjoy training opportunities. In addition, older workers displaying positive performance are more likely to receive training than older workers who perform poorly, suggesting that training late in working life may serve as a reward for good performance rather than as a means of enhancing productivity. The older the HR professional evaluating training proposals, the higher the probability that older workers will be recommended for training. keywords: training; older workers; HR professionals; factorial survey; multilevel model

Unifying the Phase Diagrams of the Magnetic and Transport Properties of La_(2-x)Sr_xCuO_4, 0 < x < 0.05

An extensive experimental and theoretical effort has led to a largely complete mapping of the magnetic phase diagram of La_(2-x)Sr_xCuO_4, and a microscopic model of the spin textures produced in the x < 0.05 regime has been shown to be in agreement with this phase diagram. Here we use this same model to derive a theory of the impurity-dominated, low temperature transport. Then, we present an analysis of previously published data for two samples: x = 0.002 data from Chen et. al., and x = 0.04 data from Keimer et. al. We show that the transport mechanisms in the two systems are the same, even though they are on opposite sides of the observed insulator-to-metal transition. Our model of impurity effects on the impurity band conduction, variable-range hopping conduction, and coulomb gap conduction, is similar to that used to describe doped semiconductors. However, for La_(2-x)Sr_xCuO_4 we find that in addition to impurity-generated disorder effects, strong correlations are important and must be treated on a equal level with disorder. On the basis of this work we propose a phase diagram that is consistent with available magnetic and transport experiments, and which connects the undoped parent compound with the lowest x value for which La_(2-x)Sr_xCuO_4 is found to be superconducting, x about 0.06.Comment: 7 pages revtex with one .ps figur

Effect of Non-Magnetic Impurities (Zn,Li) in a Hole Doped Spin-Fermion Model for Cuprates

The effect of adding non-magnetic impurities (NMI), such as Zn or Li, to high-Tc cuprates is studied applying Monte Carlo techniques to a spin-fermion model. It is observed that adding Li is qualitatively similar to doping with equal percentages of Sr and Zn. The mobile holes (MH) are trapped by the NMI and the system remains insulating and commensurate with antiferromagnetic (AF) correlations. This behavior persists in the region %NMI > %MH. On the other hand, when %NMI < %MH magnetic and charge incommensurabilities are observed. The vertical or horizontal hole-rich stripes, present when % NMI=0 upon hole doping, are pinned by the NMI and tend to become diagonal, surrounding finite AF domains. The %MH-%NMI plane is investigated. Good agreement with experimental results is found in the small portion of this diagram where experimental data are available. Predictions about the expected behavior in the remaining regions are made.Comment: Four pages with four figures embedded in tex