754 research outputs found
Formation of viable cell fragments by treatment with colchicine
Time-lapse cinematography of human fibroblasts revealed that mitotic cells separated into numerous cell fragments containing varying amounts of chromatin and cytoplasm when treated with colchicine. As cell fragments were very loosely attached to the surface of the culture vessel during their formation, they could be easily detached like mitotic cells by gently shaking the vessel and thus separated from normal interphase cells. Fragments obtained by this procedure were able to exclude trypan blue indicating, therefore, an intact cell membrane. When placed into Petri dishes many of them attached to and even spread out on the surface. Five hours later the majority of the attached fragments incorporated [3H]leucine. Time-lapse films showed that fragments were able to extend and retract pseudopodia at least for several hours after their formation. Although the fragments degenerated within a few days, in the present experiments the possibility was not excluded that fragments which had lost only a very small amount of chromatin and cytoplasm survived for longer periods of time. The observations clearly indicate viability of many newly formed fragments
The Analysis of Speech Act in a Comic Conversation
The purpose of this research was to analyze speech act of comic conversation. An utterance has two kinds of meaning, they are, Proportional meaning (locutionary meaning): is a speech act that a speaker performs when referring or predicting an utterance or the literal meaning of what is said. This is basic literal meaning of the utterance which is conveyed by the particular words and structures that the utterance contain, and Illocutionary meaning (illocutionary force): the social function of what is said. This is the real meaning the speaker intends to express. There are five speech acts classification; they are, First, Representative: statements may be judged true or false because they aim to describe a state of affairs in the world. Second, Directive: statements attempt to make the other person's actions fit the propositional content. Third, Comissive: A statements that commits the speaker to doing something in the future. Then, Expressive: A statement in which the speaker expresses feeling and attitudes about something. And the last, Declarative: statements that attempt to change the world by “representing it as having been changed”. Maxims conversation is one of the instrument to develop the conversation to be good. The theory can be identified four unit, they are: Quality: make your contribution truthful and sincere, Quantity: provide sufficient information, Relation: make your contribution a relevant one, and Manner: make your contribution brief, present it in an orderly fashion and avoid ambiguisties. The focuses of this study are to describe the locutionary and ilocutionary meaning of used in the comic and to describe the speech act classification used in the comic.In this research, researcher used qualitative and the tool of data collection was used documentation. the researcher tried to analyze the data using Ethnography of communication Dell Hymes's SPEAKING mnemonic
Genetic disorders of neurotransmitter release machinery
Synaptic neurotransmitter release is an evolutionarily conserved process that mediates rapid information transfer between neurons as well as several peripheral tissues. Release of neurotransmitters are ensured by successive events such as synaptic vesicle docking and priming that prepare synaptic vesicles for rapid fusion. These events are orchestrated by interaction of different presynaptic proteins and are regulated by presynaptic calcium. Recent studies have identified various mutations in different components of neurotransmitter release machinery resulting in aberrant neurotransmitter release, which underlie a wide spectrum of psychiatric and neurological symptoms. Here, we review how these genetic alterations in different components of the core neurotransmitter release machinery affect the information transfer between neurons and how aberrant synaptic release affects nervous system function
Reelin Mobilizes a VAMP7-Dependent Synaptic Vesicle Pool and Selectively Augments Spontaneous Neurotransmission
SummaryReelin is a glycoprotein that is critical for proper layering of neocortex during development as well as dynamic regulation of glutamatergic postsynaptic signaling in mature synapses. Here, we show that Reelin also acts presynaptically, resulting in robust rapid enhancement of spontaneous neurotransmitter release without affecting properties of evoked neurotransmission. This effect of Reelin requires a modest but significant increase in presynaptic Ca2+ initiated via ApoER2 signaling. The specificity of Reelin action on spontaneous neurotransmitter release is encoded at the level of vesicular SNARE machinery as it requires VAMP7 and SNAP-25 but not synaptobrevin2, VAMP4, or vti1a. These results uncover a presynaptic regulatory pathway that utilizes the heterogeneity of synaptic vesicle-associated SNAREs and selectively augments action potential-independent neurotransmission
Robust Tests for Convergence Clubs
In many applications common in testing for convergence the number of cross-sectional units is large and the number of time periods are few. In these situations asymptotic tests based on an omnibus null hypothesis are characterised by a number of problems. In this paper we propose a multiple pairwise comparisons method based on an a recursive bootstrap to test for convergence with no prior information on the composition of convergence clubs. Monte Carlo simulations suggest that our bootstrap-based test performs well to correctly identify convergence clubs when compared with other similar tests that rely on asymptotic arguments. Across a potentially large number of regions, using both cross-country and regional data for the European Union we find that the size distortion which afflicts standard tests and results in a bias towards finnding less convergence, is ameliorated when we utilise our bootstrap test
Reply to Comments on Effect of heating rate on kinetic parameters of beta-irradiated Li2B4O7:Cu,Ag,P in TSL measurements
We appreciate the opportunity to respond to comments regarding the paper published by Ege et al (2007 Effect of heating rate on kinetic parameters of beta-irradiated Li2B4O7: Cu, Ag, P in TSL measurements Meas. Sci. Technol. 18 889). We would like to thank the authors for taking the time to tell us about their opinion, but unfortunately we do not agree with them completely. In the article presented by Kumar and Chourasiya some comment is advanced to the analysis of the glow curves measured with different heating rates, presented in our recent study. According to our study, the area under the glow curve decreases with increasing heating rate in TL-temperature plots due to the quenching effects. Contrary to this, Kumar and Chourasiya suggest that this decrease is due to the normalization process. Here we hope to clarify any confusion regarding our published study
Egypt’s 2011–2012 parliamentary elections: Voting for religious vs. secular democracy?
This study investigates whether individuals’ attitudes towards democracy and
secular politics have any influence on voting behavior in Egypt. Based on data
from a survey conducted immediately after the Egyptian parliamentary elections
in January 2012, this study finds that Egyptians’ attitudes towards democratic
governance were quite negative around the parliamentary elections, yet Egyptians
still endorsed democracy as the ideal political system for their country. However,
empirical findings suggest that support for democracy has a limited impact on
electoral results. On the other hand, the main division in Egyptian society around
the first free and fair parliamentary elections was the religious-secular cleavage. As
people support secular politics more, they become significantly less likely to vote
for Islamist parties. These results illustrate that preferences in regard to the type
of democracy – either a liberal and secular or a religious democracy – were
the main determinant of the historic 2012 elections in Egypt
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