Miracle-dz/UniFAR-FTUs huggingface dataset:
Persistent Cell Motion in the Absence of External Signals: A Search Strategy for Eukaryotic Cells

Background Eukaryotic cells are large enough to detect signals and then orient to them by differentiating the signal strength across the length and breadth of the cell. Amoebae, fibroblasts, neutrophils and growth cones all behave in this way. Little is known however about cell motion and searching behavior in the absence of a signal. Is individual cell motion best characterized as a random walk? Do individual cells have a search strategy when they are beyond the range of the signal they would otherwise move toward? Here we ask if single, isolated, Dictyostelium and Polysphondylium amoebae bias their motion in the absence of external cues. Methodology We placed single well-isolated Dictyostelium and Polysphondylium cells on a nutrient-free agar surface and followed them at 10 sec intervals for ∼10 hr, then analyzed their motion with respect to velocity, turning angle, persistence length, and persistence time, comparing the results to the expectation for a variety of different types of random motion. Conclusions We find that amoeboid behavior is well described by a special kind of random motion: Amoebae show a long persistence time (∼10 min) beyond which they start to lose their direction; they move forward in a zig-zag manner; and they make turns every 1–2 min on average. They bias their motion by remembering the last turn and turning away from it. Interpreting the motion as consisting of runs and turns, the duration of a run and the amplitude of a turn are both found to be exponentially distributed. We show that this behavior greatly improves their chances of finding a target relative to performing a random walk. We believe that other eukaryotic cells may employ a strategy similar to Dictyostelium when seeking conditions or signal sources not yet within range of their detection system.
In vivo development of nicotinic acetylcholine receptor channels in Xenopus myotomal muscle

The development of acetylcholine receptor (AChR) channel function in Xenopus myotomal muscle was studied by single-channel recordings from cell-attached patches of nonjunctional membrane in vivo. AChR channels were studied from the time of their first appearance on the muscle membrane until the time of full maturity of the muscle. Two predominant amplitude classes of AChR channels were observed with slope conductances of about 40 and 60 pS. During the first day after their initial appearance on the membrane, the small-conductance channels were the most numerous class on the muscle membrane. The large-conductance channels then began to be expressed in significant numbers and, over the next 2 d, became the predominant channel type. The large- conductance class had an apparent mean open time of approximately 0.7 msec at resting potential, which remained constant throughout development. The small channel initially had an apparent open time of approximately 3 msec at resting potential, which decreased during development by about 50%. The decrease in open time of the small channel was correlated in time with the increased expression of the large-conductance channels. Openings of the large-conductance channels were generally separated by closed intervals of more than 1 msec, whereas openings of the small-conductance channels were commonly interrupted by brief gaps of about 0.2 msec duration. The duration of the brief gaps did not change during development.
How Goals and Beliefs Lead People into and Out of Depression

There is evidence that beliefs (cognitive vulnerabilities) and goals (to prove self-worth) contribute to depression but little consideration of how they work in tandem. Synthesizing research on beliefs and goals leads us to four propositions: (a) People with cognitive vulnerabilities often adopt self-worth goals (seeking to prove self-worth and to avoid proof of worthlessness). People with the opposite beliefs often adopt learning goals. (b) Stressors trigger depression largely because they lead people with self-worth goals to focus narrowly on goals to avoid proof of worthlessness. The same stressors do not lead people with learning goals to become depressed. (c) People with goals to avoid proof of worthlessness adopt defensive self-handicapping behaviors (e.g., effort withdrawal, rumination) when dealing with stressors, because those behaviors serve their goals. The same stressors lead people with learning goals to adopt constructive, problem-solving strategies. (d) A key to alleviating depression is fostering a shift from self-worth goals to learning goals and from the beliefs underlying self-worth goals to the opposite beliefs.
The behavior and metamorphosis of the larva of Bugula neritina (Linnaeus); experimental modification of the length of the free-swimming period and the responses of the larvae to light and gravity.

1. The distribution, external morphology, swimming movements and metamorphosis of the larvae of B. neritina are discussed. During metamorphosis the eye-spots of the larva function in orientation to light.2. At room temperature (26-30° C.) the larvae under laboratory conditions are geonegative and photopositive during the larval period. Just before metamorphosis they lose their intense positive reaction to light and become more or less indifferent.3. A reduction of temperature causes larvae to become geopositive and simultaneously prolongs their free-swimming period. When either ascending or descending gradients of temperature are employed, the greater number of larvae change their responses to gravity between 20 and 23.5° C.4. In cold water (7 to 10° C.) larvae lose their intense positive response to light and become more or less indifferent. Their behavior at reduced temperatures shows that they may become geopositive without exhibiting a simultaneous negative reaction to light. Their descent to the bott.
Comparison of Clinical and Functional Outcomes Using Pectoralis Major and Cutaneous Free Flaps for Hypopharyngeal Squamous Cell Carcinoma

Background The purpose of this study was to compare postoperative morbidities and functional outcomes of pectoralis major myocutaneous (PMMC) flap and cutaneous free flap reconstruction approaches in hypopharyngeal squamous cell carcinoma patients. Methods We retrospectively reviewed records from 99 patients who underwent hypopharyngeal reconstruction with a cutaneous free flap (n=85) or PMMC flap (n=14) between 1995 and 2013. Morbidity was classified into hospitalization, medical, or flap-related complications. Functional outcomes were classified into oral re-alimentation and decannulation time. Results The overall flap-related complication rate was higher in the PMMC flap group (n=8, 57.1%; P=0.019), but the medical morbidity rate was higher in the cutaneous free flap group (n=68, 80%; P=0.006). The rate of pneumonia was higher in the cutaneous free flap group (n=48, 56.5%; P=0.020). Pulmonary premorbidity was the variable most significantly associated with pneumonia (odds ratio=3.012, P=0.012). There was no statistically significant difference in oral re-alimentation and decannulation time between the two groups. Conclusions Although the functional superiority of free flaps has been reported in many studies, our results do not support this hypothesis. One limitation of our study is the relatively smaller flap size and fewer PMMC flap cases compared with the cutaneous free flap group. The low postoperative medical morbidity incidence rate in the PMMC flap group was clinically significant; however, the free flap group had more flap-related complications. Thus, PMMC flaps should be considered a viable option, especially for patients with pulmonary premorbidities.
Children and Metaphors.

VOSNIADOU, STELLA. Children and Metaphors. CHILD DEVELOPMENT, 1987, 58, 870-885. Recent research on the development of children's abilities to comprehend and produce metaphorical language is reviewed. It is argued that the ability to produce and comprehend metaphorical language emerges out of children's undifferentiated similarity notions and develops gradually to encompass a greater variety of conceptual domains. Although we do not yet have adequate theories of how metaphor comprehension or production develop, there is good reason to believe that this is a continuous rather than a stagelike process, and that it is constrained primarily by limitations in children's knowledge and information-processing abilities. Furthermore, it appears that the comprehension and production of metaphorical language involve transfer of knowledge from one conceptual domain to another which, on the one hand, depends critically on the conceptual knowledge the child already has, and on the other acts to enrich and advance this conceptual knowledge.
China's Below-Replacement Fertility: Recent Trends and Future Prospects.

Between 1970 and 1990, China experiencoed a rapid and sharp fertility decline-from total fertility rates of approximately six births to two. The degree to which Chinese fertility has continued to fall after 1990 is controversial. We use survey data from the 1997 National Population and Reproductive Health Survey and from the 2001 Reproductive Health and Family Planning Survey to document recent trends in Chinese fertility. Our estimates provide further evidence that China's fertility is well below-replacement level at the turn of the twenty-first century-with TFR levels of approximately 1.5 children per woman. Trends in parity-specific cohort fertility by age also suggest below replacement completed fertility for cohorts still in the childbearing years. In the article's second section, we identify key components of low period fertility in order to frame our discussion of two questions: 1) in what ways is Chinese low fertility different from/similar to that in other low-fertility countries? And 2) what are the likely future trends in Chinese fertility? Copyright (c) 2009 The Population Council, Inc.
The effects of physical activity on children diagnosed with attention deficit hyperactivity disorder: a review

Attention deficit hyperactivity disorder (ADHD) is the most common neurodevelopmental psychiatric disorder among children. Despite the noted positive aspects of the disorder, it is often associated with a range of negative outcomes for that are detrimental to children's education and wider well-being. This comprehensive scoping review examined empirical literature from seven academic journal databases and specialist journals, published over 10 years, in relation to the benefits of sport/physical activity upon the effects of ADHD. The databases and time frame were chosen to give the ‘ideal [scenario] … that could answer the review question’, within the limitations of journal database access and resource available; searches of grey literature were also conducted. Ten articles were included in the final review. Due to the variation of methodological approach, sample size, and, most importantly, the form of physical activity measured, it is difficult to identify the ‘best’ form of physical activity to mediate symptoms of ADHD. However, it can be plausibly claimed that physical activity interventions may provide an alternative, non-pharmaceutical approach to management of ADHD in children.
Factors affecting e-government adoption in the state of Qatar

Electronic government (e-government) initiatives are in their early stages in many developing countries and faced with various issues pertaining to their implementation, adoption and diffusion. Although egovernment has increased transparency and improved communication and access to information for citizens, digital diffusion of information is often achieved at high cost to government agencies. Conversely, citizens’ adoption of e-government services has been less than satisfactory in most countries. While studies by researchers continue to outline the most salient adoption constructs, as well as various frameworks and models for understanding adoption, research by independent consultancy/research organisations has produced a host of statistics and league tables of good and bad practices of service delivery. Like many other developing countries, the e-government initiative in the state of Qatar has faced a number of challenges since its inception in 2000. This study utilises the Unified Theory of Acceptance and Use of Technology (UTAUT) to explore the adoption of e-government services in the state of Qatar. 1179 citizens were surveyed to collect primary data. A regression analysis was conducted to examine the influence of the factors adapted from the UTAUT on e-government adoption. Reliability test reported values of the various constructs vary between (0.74) and (0.91). The findings reveal that effort expectancy and social influences determine citizens’ behavioural intention towards e-government. Additionally, facilitating conditions and behavioural intention were found to determine citizens’ use of e-government services in Qatar. Implications for practice and research are discussed.
Isolation and Characterization of Two Ammonium Permease Genes, meaA and mepA, from Aspergillus nidulans

ABSTRACT Ammonium and the analogue methylammonium are taken into the cell by active transport systems which constitute a family of transmembrane proteins that have been identified in fungi, bacteria, plants, and animals. Two genes from Aspergillusnidulans, mepA and meaA, which encode ammonium transporters with different affinities have been characterized. The MepA transporter exhibits the highest affinity for methylammonium (Km0, 44.3 μM); in comparison, the Km for MeaA is 3.04 mM. By use of targeted gene replacement strategies, meaA and mepA deletion mutants were created. Deletion of both meaA and mepA resulted in the inability of the strain to grow on ammonium concentrations of less than 10 mM. The single meaA deletion mutant exhibited reduced growth at the same concentrations, whereas the mepA deletion mutant displayed wild-type growth. Interestingly, multiple copies of mepA were found to complement the methylammonium resistance phenotype conferred by the deletion of meaA. The expression profiles for mepA and meaA differed; the mepA transcript was detected only in nitrogen-starved cultures, whereas meaA was expressed under both ammonium-sufficient and nitrogen starvation conditions. Together, these results indicate that MeaA constitutes the major ammonium transport activity and is required for the optimal growth of A. nidulans on ammonium as the sole nitrogen source and that MepA probably functions in scavenging low concentrations of ammonium under nitrogen starvation conditions.
Saving graces: Impact of partner support and maternal attachment on partner attachments in an individualistic and a collectivist context

The current study investigated the relationships between current attachment to mother and attachment to romantic partners, and the role of current partner support and culture as moderators of that relationship. University students who were currently in a romantic relationship were recruited from Hong Kong and USA, and completed measures on attachment styles and partner support. Results showed that maternal attachment anxiety was correlated with romantic attachment anxiety; maternal attachment avoidance was correlated with romantic attachment avoidance, but this linkage varied by level of current partner support. Romantic attachment avoidance was also associated with current partner support, but this linkage was stronger for HK Chinese than for Americans. These results are discussed in terms of how interpersonal and personality factors promoted by culture can affect the developmental course of romantic relationships.
Big Five Personality Factors and Leader Emergence in Virtual Teams

Using a sample of 243 undergraduate business students assigned to 71 virtual teams, this study explored the relationships between the Big Five personality factors, leader emergence, team trustworthiness, peer rated member performance contributions, and team performance. As predicted, agreeableness and conscientiousness were positively related to the task- and social-oriented dimensions of leader emergence, respectively. Contrary to expectations, emotional stability was not related to either dimension of leadership emergence. Evidence of the predicted relationships between emergent leadership and peer ratings of member contributions to team performance was obtained for task- but not social-oriented behaviors. At the team level, aggregated social-oriented leadership behaviors predicted aggregate perceptions of team trustworthiness. Only aggregated task-oriented emergent leadership behaviors predicted virtual team performance.
The Smoking Behaviors of Adolescents and Their Friends: Do Parents Matter?

Objective. This study examines relations among adolescent smoking, parental authoritativeness, parental disapproval of smoking, parental smoking, friends' self-reported smoking, and friends' reports of their parents' authoritativeness. Design. 317 adolescents (12-15 years of age) gave saliva samples and completed questionnaires concerning their own smoking behavior, aspects of their parents' parenting behaviors (used to construct a measure of authoritative parenting), their parents' smoking behaviors, and parental disapproval of smoking. Independent reports obtained from friends were used to calculate measures of friends' smoking and levels of friends' parents' authoritativeness. Results. Higher levels of authoritative parenting and parental disapproval of smoking along with lower levels of parental smoking were associated with a lower likelihood of smoking during adolescence. Friends' smoking was positively associated with adolescent smoking, and it mediated the association between parental smoking and target adolescents' smoking. Friends' parents' authoritativeness did not mediate the association between friends' smoking and adolescent smoking. Conclusions. Along with friends' smoking, parental authoritativeness and parental disapproval of smoking are important influences on adolescent smoking. Consideration of the conjoint influence of the family and the peer group, rather than either in isolation, improves understanding of adolescent smoking behavior.
Modification of Seed Oil Composition in Arabidopsis by Artificial microRNA-Mediated Gene Silencing

Various post transcriptional gene silencing strategies have been developed and exploited to study gene function or engineer disease resistance. The recently developed artificial microRNA strategy is an alternative method of effectively silencing target genes. The Δ12-desaturase (FAD2), Fatty acid elongase (FAE1), and Fatty acyl-ACP thioesterase B (FATB) were targeted with amiR159b-based constructs in Arabidopsis thaliana to evaluate changes in oil composition when expressed with the seed-specific Brassica napus truncated napin (FP1) promoter. Fatty acid profiles from transgenic homozygous seeds reveal that the targeted genes were silenced. The down-regulation of the AtFAD-2 gene substantially increased oleic acid from the normal levels of ∼15% to as high as 63.3 and reduced total PUFA content (18:2Δ9,12 + 18:3Δ9,12,15 + 20:2Δ11,14 + 20:3Δ11,14,17) from 46.8 to 4.8%. Δ12-desaturase activity was reduced to levels as low as those in the null fad-2-1 and fad-2-2 mutants. Silencing of the FAE1 gene resulted in the reduction of eicosenoic acid (20:1Δ11) to 1.9 from 15.4% and silencing of FATB resulted in the reduction of palmitic acid (16:0) to 4.4% from 8.0%. Reduction in FATB activity is comparable with a FATB knock-out mutant. These results demonstrate for the first time amiR159b constructs targeted against three endogenous seed-expressed genes are clearly able to down-regulate and generate genotypic changes that are inherited stably over three generations.
ApoA-IV modulates the secretory trafficking of apoB and the size of triglyceride-rich lipoproteins

Although the evidence linking apoA-IV expression and triglyceride (TG)-rich lipoprotein assembly and secretion is compelling, the intracellular mechanisms by which apoA-IV could modulate these processes remain poorly understood. We therefore examined the functional impact of apoA-IV expression on endogenous apoB, TG, and VLDL secretion in stably transfected McA-RH7777 rat hepatoma cells. Expression of apoA-IV modified with the endoplasmic reticulum (ER) retention signal KDEL (apoA-IV-KDEL) dramatically decreased both the rate and efficiency of endogenous apoB secretion, suggesting a presecretory interaction between apoA-IV-KDEL and apoB or apoB-containing lipoproteins. Expression of native apoA-IV using either a constitutive or tetracycline-inducible promoter delayed the initial rate of apoB secretion and reduced the final secretion efficiency by ∼40%. However, whereas apoA-IV-KDEL reduced TG secretion by 75%, expression of native apoA-IV caused a 20–35% increase in TG secretion, accompanied by a ∼55% increase in VLDL-associated apoB, an increase in the TG:phospholipid ratio of secreted d < 1.006 lipoproteins, and a 10.1 nm increase in peak VLDL1 particle diameter. Native apoA-IV expression had a negligible impact on expression of the MTP gene. These data suggest that by interacting with apoB in the secretory pathway, apoA-IV alters the trafficking kinetics of apoB-containing TG-rich lipoproteins through cellular lipidation compartments, which in turn, enhances particle expansion and increases TG secretion.
Thoughts on teaching thinking: perceptions of practitioners with a shared culture of thinking skills education

This article aims to outline the reported experiences of practitioners in a local authority in England where, since the mid-1990s, a high proportion of teachers have undertaken professional development in the field of teaching thinking skills. The article is based on the main findings from a questionnaire survey which was carried out among first, middle and high school teachers in this area. It was intended to explore their views on the use, benefits and challenges of teaching ‘Thinking for Learning’, a term which encompasses both the use of a range of thinking skills strategies and the Community of Enquiry/Philosophy for Children approaches. The vast majority of respondents reported a range of positive effects on their pupils, including pupil motivation and cognitive, social and affective benefits. On the other hand, reported challenges mainly referred to a perceived lack of time and to some seemingly inherent difficulties in the teaching of thinking. Conclusions from this study have the potential to inform professional development practice and policy far beyond this local authority's regional boundaries, and aim to contribute to the body of knowledge about forms of education that are based on dialogue and enquiry.