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Search Results: 1 - 10 of 3663 matches for " left-right cleavage "
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Role of Political Affiliation across the European Institutions in the Dynamics of the EU Legislative Process
Radko Hokovsky,Viera Knutelska
AUCO Czech Economic Review , 2012,
Abstract: This paper addresses the question of the impact of party political affiliation on the pace of the EU legislative process. It hypothesizes that the codecision process should be faster if the key actors from the European Commission, the European Parliament and the Council are closer on the left-right policy scale or share affiliation to the same political family. The hypotheses are tested on the data covering the period of five years, from May 2004 to June 2009. While closeness on the left-right policy scale did not prove to have any effect, the findings show that if all three main actors, or at least the EP rapporteur and responsible Commissioner, come from the same political family, the codecision-process is indeed faster. The paper thus aims to contribute to the study of importance of party political ties and left-right cleavages in the EU decision-making.
Left-Right and Up-Down Mirror Image Confusion in 4-, 5- and 6-Year-Olds  [PDF]
Izumi Uehara
Psychology (PSYCH) , 2013, DOI: 10.4236/psych.2013.410104
Abstract:

Young children under the age of 8 - 9 years tend to confuse left-right mirror images, and it is thought that their linguistic skills play a crucial role in this phenomenon. However, other aspects of this confusion, such as whether children confuse up-down mirror images or whether the meaningfulness of the stimulus influences matching performance, remain unclear. The present study examined the confusion of left-right and up-down reversed images by 4-, 5- and 6-year-olds using meaningful and meaningless figures in a task in which sample and comparison stimuli were presented simultaneously. Children performed more accurately when presented with meaningful figures and confused both up-down and left-right reversed figures, although they did so less frequently in response to up-down than to left-right reversed figures. Reversal confusion was greatest in 4-year-olds and no significant differences were observed between 5- and 6-year-olds. These findings suggest that the ability to discriminate reversed images may be associated with the development of a wide range of cognitive abilities including theory of mind, executive function, and suggestibility.

Symmetry OUT, Asymmetry IN
Raquel Louren?o,Leonor Saúde
Symmetry , 2010, DOI: 10.3390/sym2021033
Abstract: The formation of a perfect vertebrate body plan poses many questions that thrill developmental biologists. Special attention has been given to the symmetric segmental patterning that allows the formation of the vertebrae and skeletal muscles. These segmented structures derive from bilaterally symmetric units called somites, which are formed under the control of a segmentation clock. At the same time that these symmetric units are being formed, asymmetric signals are establishing laterality in nearby embryonic tissues, allowing the asymmetric placement of the internal organs. More recently, a “shield” that protects symmetric segmentation from the influence of laterality cues was uncovered. Here we review the mechanisms that control symmetric versus asymmetric development along the left-right axis among vertebrates. We also discuss the impact that these studies might have in the understanding of human congenital disorders characterized by congenital vertebral malformations and abnormal laterality phenotypes.
Histone deacetylase activity is necessary for left-right patterning during vertebrate development
Katia Carneiro, Claudia Donnet, Tomas Rejtar, Barry L Karger, Gustavo A Barisone, Elva Díaz, Sandhya Kortagere, Joan M Lemire, Michael Levin
BMC Developmental Biology , 2011, DOI: 10.1186/1471-213x-11-29
Abstract: To understand how an early physiological gradient is transduced into a late, stable pattern of Nr1 expression we investigated epigenetic regulation during LR patterning. Embryos injected with mRNA encoding a dominant-negative of Histone Deacetylase (HDAC) lacked Nr1 expression and exhibited randomized sidedness of the heart and viscera (heterotaxia) at stage 45. Timing analysis using pharmacological blockade of HDACs implicated cleavage stages as the active period. Inhibition during these early stages was correlated with an absence of Nr1 expression at stage 21, high levels of heterotaxia at stage 45, and the deposition of the epigenetic marker H3K4me2 on the Nr1 gene. To link the epigenetic machinery to the 5HT signaling pathway, we performed a high-throughput proteomic screen for novel cytoplasmic 5HT partners associated with the epigenetic machinery. The data identified the known HDAC partner protein Mad3 as a 5HT-binding regulator. While Mad3 overexpression led to an absence of Nr1 transcription and randomized the LR axis, a mutant form of Mad3 lacking 5HT binding sites was not able to induce heterotaxia, showing that Mad3's biological activity is dependent on 5HT binding.HDAC activity is a new LR determinant controlling the epigenetic state of Nr1 from early developmental stages. The HDAC binding partner Mad3 may be a new serotonin-dependent regulator of asymmetry linking early physiological asymmetries to stable changes in gene expression during organogenesis.Despite a bilaterally-symmetrical bodyplan, many animals exhibit a consistent asymmetry in the placement and shape of the heart, viscera, and brain [1]. The wide-spread conservation of laterality, and the consistent linkage of the orientation of the left-right (LR) axis with the dorso-ventral and anterior-posterior axes (in a world that does not distinguish left from right above the quantum level), make LR patterning a fascinating problem [2-4]. In addition to its relevance to basic cell, developmental, a
Identidades ideológicas e partidárias na europa: Portugal, Espanha e Grécia em perspectiva comparativa
Freire,André;
Sociologia, Problemas e Práticas , 2005,
Abstract: this article undertakes a systematic comparison of the extent and development of ideological and party-political identities among the electorate in the new democracies of southern europe (portugal, spain and greece) with those of electorates in eight other democratic countries of the old continent from 1976 to 2002. bearing in mind the intervening periods when dictatorships ruled in southern europe, the conditions for forming party-political and ideological identities, particularly in terms of left and right were not favourable. for this reason the article seeks to establish in the first instance whether party-political and ideological identity is less well disseminated among the people of the new democracies; and secondly, it demonstrates growth trends which may go counter to those in the older democracies.
Left-right voting in 10th Saeima and Riigikogu elections in 2011
Vikmane E.,Kreituse I.
SHS Web of Conferences , 2012, DOI: 10.1051/shsconf/20120200038
Abstract: Distribution of parties along ideological continuum historically has been the issue of governmental accountability, has served as a competition platform and communication code between political candidates and potential voters. Debate on the framework of the left-right continuum and its impact on voting behaviour are still ongoing in the Western countries, generally recognising the split as such, and rather debating its changing nature. The aim of the paper is to highlight the left-right continuum as a meaningful notion in the research of electoral behaviour both in Latvia and Estonia according to the thesis that voters in general tend to choose a party in elections which corresponds (or lies closest) to their self-placement in the left-right continuum (Downs, 1957); and the Laponce’s thesis concerning the left-right continuum as the “political Esperanto” – a language allowing parties and voters to understand each other (Laponce, 1981). Results of this research show that although the opinion of the parties themselves and experts concerning placement of the parties along the left-right scale coincides, the left-right continuum does not serve as the “political Esperanto” between the parties and voters. Still the idea of voting for the party, which is closest to one’s own opinion, is particularly well pronounced in Latvia.
Symmetry versus Asymmetry in the Molecules of Life: Homomeric Protein Assemblies
Biserka Koji?-Prodi?,Zoran ?tefani?
Symmetry , 2010, DOI: 10.3390/sym2020884
Abstract: The essay is dedicated to the relation of symmetry and asymmetry-chirality in Nature. The Introduction defines symmetry and its impact on basic definitions in science and human activities. The following section Chirality of molecules reveals breifly development of notion of chirality and its significance in living organisms and science. Homochirality is a characteristic hallmark of life and its significance is presented in the section Homochirality of Life. Proteins, important constituents of living cells performing versatile functions are chiral macromolecules composed of L-amino acids. In particular, the protein assemblies are of a great importance in functions of a cell. Therefore, they have attracted researches to examine them from different points of view. Among proteins of known three-dimensional structures about 50–80% of them exist as homomeric protein complexes. Protein monomers lack any intrinsic, underlying symmetry, i.e. enantiomorphic protein molecules involve left-handed amino acids but their asymmetry does not appear to extend to the level of quaternary structures (homomeric complexes) as observed by Chothia in 1991. In the section Homomeric assemblies we performed our analysis of very special cases of homomers revealing non-crystallographic symmetry in crystals. Homochiral proteins can crystallize only in enantiomorphic space groups. Among 230 existing space groups 65 are enantiomorphic containing limited symmetry elements that are rotation and screw-rotation axes. Any axis of rotation symmetry of a crystal lattice must be two-fold, three-fold, four-fold, or six-fold. Five-fold, seven-fold, and higher-fold rotation symmetry axes are incompatible with the symmetry under spatial displacement of the three-dimensional crystal lattice.
Mapping of dextral : sinistral proportions in the chirally dimorphic land snail Amphidromus inversus
Menno Schilthuizen,Sylvia Looijestijn,Sek Chuan Chua,Ruth F. Castillo Cajas
PeerJ , 2015, DOI: 10.7287/peerj.preprints.470v1
Abstract: One of the very few snail taxa that display genetic antisymmetry (that is, roughly even mixes of genetically determined clockwise and anticlockwise individuals within a single population) are the circa 35 species of the tropical tree snail subgenus Amphidromus. Previous work has shown that this may be due to a particular type of sexual selection, in which sperm transfer is improved in copulations between the two mirror-image morphs. However, it is not yet clear why so often significant deviations from 50:50 proportions are found. Modelling studies show that population structure will affect the degree by which the dimorphism is skewed towards the morph associated with the recessive allele. In this study, we mapped the proportions of sinistrals (PropS) in 56 demes in A. inversus on the Malaysian island of Kapas. We also mapped population density, predation rates, and several measures of vegetation structure. Our results show that PropS amounts on average to 0.65, but across the island varies from 0.30 to 0.85. Density and overall predation are inversely correlated, but neither predicts PropS. Vegetation parameters also do not correlate with the proportion of sinistrals. We do, however, find a negative correlation between the predation rate on sinistrals and PropS, a finding which may warrant further study.
Left-right coupling of circularly polarized light propagating inside biaxially gyrotropic left-handed media
双轴螺旋向性负材料中极化光波的左-右旋偏振耦合

Shen Jian-Qi,Zhuang Fei,
沈建其
,庄 飞

物理学报 , 2004,
Abstract: The left right coupling of circularly polarized light in biaxially gyrotropic left handed media is considered in the present paper. It is shown that this left right coupling gives rise to the frequency shifts of both left and right handed polarized light propagating inside the biaxially gyrotropic left handed media. In addition, we discuss the physical origin of left right couplings of polarized light ( i.e., the nonlocal polarization effect), and its potential applications ( e.g., controllable position dependent frequency shifts) in information science.
Ciliary and non-ciliary expression and function of PACRG during vertebrate development
Thomas Thumberger, Cathrin Hagenlocher, Matthias Tisler, Tina Beyer, Nina Tietze, Axel Schweickert, Kerstin Feistel, Martin Blum
Cilia , 2012, DOI: 10.1186/2046-2530-1-13
Abstract: PACRG cDNAs were cloned and expression was analyzed during early embryonic development of Xenopus, mouse, rabbit and zebrafish. Antisense morpholino oligonucleotide (MO) mediated gene knockdown was applied in Xenopus to investigate LR development at the level of tissue morphology, leftward flow and asymmetric marker gene expression, using timelapse videography, scanning electron microscopy (SEM) and whole-mount in situ hybridization. Results were statistically evaluated using Wilcoxon paired and χ2 tests.PACRG mRNA expression was found in cells and tissues harboring cilia throughout the vertebrates. Highly localized expression was also detected in the brain. During early development, PACRG was specifically localized to epithelia where leftward flow arises, that is, the gastrocoel roof plate (GRP) in Xenopus, the posterior notochord (PNC) in mammals and Kupffer’s vesicle (KV) in zebrafish. Besides its association with ciliary axonemes, subcellular localization of PACRG protein was found around the nucleus and in a spotty pattern in the cytoplasm. A green fluorescent protein (GFP) fusion construct preferentially labeled cilia, rendering PACRG a versatile marker for live imaging. Loss-of-function in the frog resulted dose dependently in LR, neural tube closure and gastrulation defects, representing ciliary and non-ciliary functions of PACRG.The PACRG protein is a novel essential factor of cilia in Xenopus.PACRG was originally identified as a gene related to Parkinson’s disease (PD) in humans [1,2]. In mammals PACRG shares a bidirectional promoter with Park2, the target gene for early onset juvenile PD. PACRG represents an evolutionarily very highly conserved gene, which is present from green algae to mammals [1,3,4]. Although a precise function has yet to be ascribed, the available evidence suggests that the PACRG protein is associated with the ciliary axoneme: antibodies or green fluorescent protein (GFP) fusion proteins detected PACRG in flagellae of Chlamydomonas re
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