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Sample records for fibroblasts self-direct multicellular

  1. Self-Directed Workplace Learning.

    ERIC Educational Resources Information Center

    1998

    This document contains four papers from a symposium on self-directed workplace learning. "Self-Directed Work Teams: Implementation and Performance" (Marcel van der Klink, Hilde ter Horst) discusses the results of a study examining the implementation and effects of self-directed work teams in a land register office and the role of the department's…

  2. Stabilizing multicellularity through ratcheting.

    PubMed

    Libby, Eric; Conlin, Peter L; Kerr, Ben; Ratcliff, William C

    2016-08-19

    The evolutionary transition to multicellularity probably began with the formation of simple undifferentiated cellular groups. Such groups evolve readily in diverse lineages of extant unicellular taxa, suggesting that there are few genetic barriers to this first key step. This may act as a double-edged sword: labile transitions between unicellular and multicellular states may facilitate the evolution of simple multicellularity, but reversion to a unicellular state may inhibit the evolution of increased complexity. In this paper, we examine how multicellular adaptations can act as evolutionary 'ratchets', limiting the potential for reversion to unicellularity. We consider a nascent multicellular lineage growing in an environment that varies between favouring multicellularity and favouring unicellularity. The first type of ratcheting mutations increase cell-level fitness in a multicellular context but are costly in a single-celled context, reducing the fitness of revertants. The second type of ratcheting mutations directly decrease the probability that a mutation will result in reversion (either as a pleiotropic consequence or via direct modification of switch rates). We show that both types of ratcheting mutations act to stabilize the multicellular state. We also identify synergistic effects between the two types of ratcheting mutations in which the presence of one creates the selective conditions favouring the other. Ratcheting mutations may play a key role in diverse evolutionary transitions in individuality, sustaining selection on the new higher-level organism by constraining evolutionary reversion.This article is part of the themed issue 'The major synthetic evolutionary transitions'. PMID:27431522

  3. Stabilizing multicellularity through ratcheting

    PubMed Central

    Libby, Eric; Conlin, Peter L.; Kerr, Ben; Ratcliff, William C.

    2016-01-01

    The evolutionary transition to multicellularity probably began with the formation of simple undifferentiated cellular groups. Such groups evolve readily in diverse lineages of extant unicellular taxa, suggesting that there are few genetic barriers to this first key step. This may act as a double-edged sword: labile transitions between unicellular and multicellular states may facilitate the evolution of simple multicellularity, but reversion to a unicellular state may inhibit the evolution of increased complexity. In this paper, we examine how multicellular adaptations can act as evolutionary ‘ratchets’, limiting the potential for reversion to unicellularity. We consider a nascent multicellular lineage growing in an environment that varies between favouring multicellularity and favouring unicellularity. The first type of ratcheting mutations increase cell-level fitness in a multicellular context but are costly in a single-celled context, reducing the fitness of revertants. The second type of ratcheting mutations directly decrease the probability that a mutation will result in reversion (either as a pleiotropic consequence or via direct modification of switch rates). We show that both types of ratcheting mutations act to stabilize the multicellular state. We also identify synergistic effects between the two types of ratcheting mutations in which the presence of one creates the selective conditions favouring the other. Ratcheting mutations may play a key role in diverse evolutionary transitions in individuality, sustaining selection on the new higher-level organism by constraining evolutionary reversion. This article is part of the themed issue ‘The major synthetic evolutionary transitions’. PMID:27431522

  4. Current Developments in Self-Directed Learning.

    ERIC Educational Resources Information Center

    Long, Huey B.; And Others

    This document contains the following papers examining current developments in self-directed learning: "Self-Directed Learning: Challenges and Opportunities" (Huey B. Long); "Examination of Self-Directed Learning Readiness and Selected Demographic Variables of Top Female Executives" (Lucy M. Guglielmino); "Enhancing Self-Directed Learning in the…

  5. Expanding Horizons in Self-Directed Learning.

    ERIC Educational Resources Information Center

    Long, Huey B.; And Others

    The following papers are included: "Preface" (Huey B. Long); "Self-Directed Learning: Smoke and Mirrors?" (Huey B. Long); "From Self-Culture to Self-Direction: An Historical Analysis of Self-Directed Learning" (Amy D. Rose); "The Link between Self-Directed and Transformative Learning" (Jane Pilling-Cormick); "Learner Orientations among Baby…

  6. Robustness in multicellular systems

    NASA Astrophysics Data System (ADS)

    Xavier, Joao

    2011-03-01

    Cells and organisms cope with the task of maintaining their phenotypes in the face of numerous challenges. Much attention has recently been paid to questions of how cells control molecular processes to ensure robustness. However, many biological functions are multicellular and depend on interactions, both physical and chemical, between cells. We use a combination of mathematical modeling and molecular biology experiments to investigate the features that convey robustness to multicellular systems. Cell populations must react to external perturbations by sensing environmental cues and acting coordinately in response. At the same time, they face a major challenge: the emergence of conflict from within. Multicellular traits are prone to cells with exploitative phenotypes that do not contribute to shared resources yet benefit from them. This is true in populations of single-cell organisms that have social lifestyles, where conflict can lead to the emergence of social ``cheaters,'' as well as in multicellular organisms, where conflict can lead to the evolution of cancer. I will describe features that diverse multicellular systems can have to eliminate potential conflicts as well as external perturbations.

  7. Emerging Perspectives of Self-Directed Learning.

    ERIC Educational Resources Information Center

    Long, Huey B.; And Others

    These 17 papers attest to the deepening and broadening interest in self-directed learning as one solution to the lifelong learning needs of men and women in an increasingly dynamic society. The papers include the following: "Self-Directed Learning Knowledge: Some Issues" (Long); "Development of Self-Directed Learning Readiness: A Longitudinal…

  8. Self Directed Learning and Self Management. Symposium.

    ERIC Educational Resources Information Center

    2002

    This document contains three papers from a symposium on self-directed learning and self-management. "Validating a More-Dimensional Conception of Self-Directed Learning" (Gerald A. Straka, Cornelia Schaefer) discusses the development and validation of a conception of self-directed learning as a dynamic interplay between behavior, information,…

  9. Collective Calcium Signaling of Defective Multicellular Networks

    NASA Astrophysics Data System (ADS)

    Potter, Garrett; Sun, Bo

    2015-03-01

    A communicating multicellular network processes environmental cues into collective cellular dynamics. We have previously demonstrated that, when excited by extracellular ATP, fibroblast monolayers generate correlated calcium dynamics modulated by both the stimuli and gap junction communication between the cells. However, just as a well-connected neural network may be compromised by abnormal neurons, a tissue monolayer can also be defective with cancer cells, which typically have down regulated gap junctions. To understand the collective cellular dynamics in a defective multicellular network we have studied the calcium signaling of co-cultured breast cancer cells and fibroblast cells in various concentrations of ATP delivered through microfluidic devices. Our results demonstrate that cancer cells respond faster, generate singular spikes, and are more synchronous across all stimuli concentrations. Additionally, fibroblast cells exhibit persistent calcium oscillations that increase in regularity with greater stimuli. To interpret these results we quantitatively analyzed the immunostaining of purigenic receptors and gap junction channels. The results confirm our hypothesis that collective dynamics are mainly determined by the availability of gap junction communications.

  10. Self-Directed Job Search: An Introduction.

    ERIC Educational Resources Information Center

    Employment and Training Administration (DOL), Washington, DC.

    This document provides an introduction to a job search training activity--self-directed job search--which can be implemented by Private Industry Councils (PICs) or Comprehensive Employment and Training Act (CETA) Prime Sponsors. The first section introduces self-directed job search for the economically disadvantaged. The next section describes…

  11. Self-Directed Learning: Consensus & Conflict.

    ERIC Educational Resources Information Center

    Long, Huey B.; And Others

    The following papers are presented in this book: "Self-Directed Learning: Consensus and Conflict" (Long); "Challenges in the Study and Practice of Self-Directed Learning" (Long); "A Conceptual Model of Autodidactism" (Tremblay, Theil); "Functional and Dysfunctional Uses of Self-Directedness in Adult Learning" (Bonham); "Relationship between Scores…

  12. Self-Directed Learning: Exploring the Fears.

    ERIC Educational Resources Information Center

    Ricard, Virginia B.

    Many degree programs for adults include a self-directed learning component to offer learners the opportunity to use mature skills in a flexible learning environment. Problems with making the self-directed component work may be the learning setting, learner attitudes, and fears of both skilled and less skilled adult learners. Some learner fears are…

  13. Games of multicellularity.

    PubMed

    Kaveh, Kamran; Veller, Carl; Nowak, Martin A

    2016-08-21

    Evolutionary game dynamics are often studied in the context of different population structures. Here we propose a new population structure that is inspired by simple multicellular life forms. In our model, cells reproduce but can stay together after reproduction. They reach complexes of a certain size, n, before producing single cells again. The cells within a complex derive payoff from an evolutionary game by interacting with each other. The reproductive rate of cells is proportional to their payoff. We consider all two-strategy games. We study deterministic evolutionary dynamics with mutations, and derive exact conditions for selection to favor one strategy over another. Our main result has the same symmetry as the well-known sigma condition, which has been proven for stochastic game dynamics and weak selection. For a maximum complex size of n=2 our result holds for any intensity of selection. For n≥3 it holds for weak selection. As specific examples we study the prisoner's dilemma and hawk-dove games. Our model advances theoretical work on multicellularity by allowing for frequency-dependent interactions within groups. PMID:27179461

  14. Moving Toward Self-directed Learning

    ERIC Educational Resources Information Center

    Jackson, Mae L.

    1973-01-01

    Independent learning and self direction is emphasized in an upper-grade classroom in Eugene, Oregon. The children take part in activities like spinning thread, role-playing, and constructing picture-story books for kindergarteners. (ST)

  15. Biological soliton in multicellular movement

    NASA Astrophysics Data System (ADS)

    Kuwayama, Hidekazu; Ishida, Shuji

    2013-07-01

    Solitons have been observed in various physical phenomena. Here, we show that the distinct characteristics of solitons are present in the mass cell movement of non-chemotactic mutants of the cellular slime mould Dictyostelium discoideum. During starvation, D. discoideum forms multicellular structures that differentiate into spore or stalk cells and, eventually, a fruiting body. Non-chemotactic mutant cells do not form multicellular structures; however, they do undergo mass cell movement in the form of a pulsatile soliton-like structure (SLS). We also found that SLS induction is mediated by adhesive cell-cell interactions. These observations provide novel insights into the mechanisms of biological solitons in multicellular movement.

  16. Interpreting Ellenore Flood's Self-Directed Search.

    ERIC Educational Resources Information Center

    Rayman, Jack R.

    1998-01-01

    Presents and responds to questions the author would ask himself before meeting with a client whose Self-Directed Search he has reviewed. The client in the case is a 29-year-old female high school teacher faced with four occupational opportunities from which she is trying to make a choice. (MKA)

  17. Self-Directed Learning and Lifespan Development.

    ERIC Educational Resources Information Center

    Kasworm, Carol

    1983-01-01

    The mission of lifelong learning encompasses a holistic, universal, educative framework embedded in acts of self-directed, self-initiated learning. Key to these lifelong learning actions are both facilitative environments and resources for individual learning activities, as well as the development of individual structures and processes to create,…

  18. Self-Directed Learning: Critical Practice.

    ERIC Educational Resources Information Center

    Hammond, Merryl; Collins, Rob

    This book describes the framework for an individualistic approach to learning--critical self-directed learning (SDL). A preface explains what is meant by "critical practice of SDL," describes educational streams that have fed into the concept, and situates the context within which the ideas about critical SDL developed. The order of the chapters…

  19. Self-Directed Learning in the Workplace

    ERIC Educational Resources Information Center

    Park, Sunyoung

    2008-01-01

    The paper explores the concept of self-directed learning (SDL) in the workplace. This paper introduces a definition and argument for the importance of SDL, presents conditions that promote SDL, and suggests how future issues and implications should be applied for greater understanding and utilization of SDL in the workplace. The significance of…

  20. Fostering Self-Directed Learners through Competitions

    ERIC Educational Resources Information Center

    Lafrenz, Lu Ann; Murray, Bernadine

    2005-01-01

    Educational programs are continually seeking ways to encourage students' independence, personal growth, and self-directed learning. Graduates should enter the fashion industry with the ability to engage in lifelong learning in order to ensure competence in professional practice. Competition experiences help students to achieve these goals. The…

  1. Principal Development: Self-Directed Project Efficacy

    ERIC Educational Resources Information Center

    Piggot-Irvine, Eileen

    2011-01-01

    The inclusion of self-directed projects as an element within a New Zealand principal development programme was designed to reflect increasing support internationally for such a context-specific "inquiry" approach. The results reported in this article suggest that considerable clarity is required for such projects if they are to realize the…

  2. Cinegrams for Self-Directed Learning.

    ERIC Educational Resources Information Center

    Fischer, Detlev; Richards, Clive

    1995-01-01

    Presents potential uses of cinegrams for self-directed learning; shows how these interactive animated diagrams for technical documentation and training serve as browsing tools for the exploration of interrelated engine subsystems. Describes the development of a cinegram prototype implemented in HyperCard that shows the oil system of a Rolls Royce…

  3. Self-Directed Behavioural Family Intervention

    ERIC Educational Resources Information Center

    Morawska, Alina; Sanders, Matthew R.

    2006-01-01

    Behavioural family intervention is effective for the prevention and treatment of a wide range of emotional and behavioural problems in children. There is a growing need to address the accessibility of these services. This paper reviews the literature on self-directed interventions designed to help parents manage difficult child behaviours.…

  4. On The Evolution of Bacterial Multicellularity

    PubMed Central

    Lyons, Nicholas A.; Kolter, Roberto

    2015-01-01

    Multicellularity is one of the most prevalent evolutionary innovations and nowhere is this more apparent than in the bacterial world, which contains many examples of multicellular organisms in a surprising array of forms. Due to their experimental accessibility and the large and diverse genomic data available, bacteria enable us to probe fundamental aspects of the origins of multicellularity. Here we discuss examples of multicellular behaviors in bacteria, the selective pressures that may have led to their evolution, possible origins and intermediate stages, and whether the ubiquity of apparently convergent multicellular forms argues for its inevitability. PMID:25597443

  5. On the evolution of bacterial multicellularity.

    PubMed

    Lyons, Nicholas A; Kolter, Roberto

    2015-04-01

    Multicellularity is one of the most prevalent evolutionary innovations and nowhere is this more apparent than in the bacterial world, which contains many examples of multicellular organisms in a surprising array of forms. Due to their experimental accessibility and the large and diverse genomic data available, bacteria enable us to probe fundamental aspects of the origins of multicellularity. Here we discuss examples of multicellular behaviors in bacteria, the selective pressures that may have led to their evolution, possible origins and intermediate stages, and whether the ubiquity of apparently convergent multicellular forms argues for its inevitability. PMID:25597443

  6. 42 CFR 441.740 - Self-directed services.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 4 2014-10-01 2014-10-01 false Self-directed services. 441.740 Section 441.740... Self-directed services. (a) State option. The State may choose to offer an election for self-directing HCBS. The term “self-directed” means, with respect to State plan HCBS listed in § 440.182 of...

  7. 42 CFR 441.452 - Self-direction: General.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 4 2011-10-01 2011-10-01 false Self-direction: General. 441.452 Section 441.452 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Optional Self-Directed Personal Assistance Services Program § 441.452 Self-direction: General. (a)...

  8. 42 CFR 441.452 - Self-direction: General.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Self-direction: General. 441.452 Section 441.452 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Optional Self-Directed Personal Assistance Services Program § 441.452 Self-direction: General. (a)...

  9. Advances in Research and Practice in Self-Directed Learning.

    ERIC Educational Resources Information Center

    Long, Huey B.; And Others

    Selected papers presented in this book are: "Changing Concepts of Self-Direction in Learning" (Long); "The Transition from Learner-Control to Autodidaxy: More than Meets the Eye" (Candy); "Self-Directed Learning and the Theory of Adult Education" (Jarvis); "On the Theme and Variations of Self-Directed Learning" (Gerstner); "Self-Directed…

  10. European Views of Self-Directed Learning: Historical, Conceptual, Empirical, Practical, Vocational. LOS, Learning Organized Self-Directed Researchgroup.

    ERIC Educational Resources Information Center

    Straka, Gerald A., Ed.

    Following an Introduction by editor Gerald A. Straka that posits various definitions of self-directed learning and discusses the views of the various authors in the text, this book consists of nine papers addressing issues and conceptions of self-directed learning in Europe. The following are included: "Self-Directed Learning in Continuing…

  11. Conceptions of Self-Directed Learning: Theoretical and Conceptual Considerations. LOS, Learning Organized Self-Directed Researchgroup.

    ERIC Educational Resources Information Center

    Straka, Gerald A., Ed.

    This book consists of 15 papers addressing issues and conceptions of self-directed learning. The following are included: "Self-Directed Learning as a Political Idea" (Stephen D. Brookfield); "Social Influences on Individual Commitment to Self-Directed Learning at Work" (Alan J. Brown); "Goals of Self-Learning" (Rosemary S. Caffarella); "From…

  12. A Synthetic Multicellular Memory Device.

    PubMed

    Urrios, Arturo; Macia, Javier; Manzoni, Romilde; Conde, Núria; Bonforti, Adriano; de Nadal, Eulàlia; Posas, Francesc; Solé, Ricard

    2016-08-19

    Changing environments pose a challenge to living organisms. Cells need to gather and process incoming information, adapting to changes in predictable ways. This requires in particular the presence of memory, which allows different internal states to be stored. Biological memory can be stored by switches that retain information on past and present events. Synthetic biologists have implemented a number of memory devices for biological applications, mostly in single cells. It has been shown that the use of multicellular consortia provides interesting advantages to implement biological circuits. Here we show how to build a synthetic biological memory switch using an eukaryotic consortium. We engineered yeast cells that can communicate and retain memory of changes in the extracellular environment. These cells were able to produce and secrete a pheromone and sense a different pheromone following NOT logic. When the two strains were cocultured, they behaved as a double-negative-feedback motif with memory. In addition, we showed that memory can be effectively changed by the use of external inputs. Further optimization of these modules and addition of other cells could lead to new multicellular circuits that exhibit memory over a broad range of biological inputs. PMID:27439436

  13. Constraint Based Modeling Going Multicellular

    PubMed Central

    Martins Conde, Patricia do Rosario; Sauter, Thomas; Pfau, Thomas

    2016-01-01

    Constraint based modeling has seen applications in many microorganisms. For example, there are now established methods to determine potential genetic modifications and external interventions to increase the efficiency of microbial strains in chemical production pipelines. In addition, multiple models of multicellular organisms have been created including plants and humans. While initially the focus here was on modeling individual cell types of the multicellular organism, this focus recently started to switch. Models of microbial communities, as well as multi-tissue models of higher organisms have been constructed. These models thereby can include different parts of a plant, like root, stem, or different tissue types in the same organ. Such models can elucidate details of the interplay between symbiotic organisms, as well as the concerted efforts of multiple tissues and can be applied to analyse the effects of drugs or mutations on a more systemic level. In this review we give an overview of the recent development of multi-tissue models using constraint based techniques and the methods employed when investigating these models. We further highlight advances in combining constraint based models with dynamic and regulatory information and give an overview of these types of hybrid or multi-level approaches. PMID:26904548

  14. The origin of multicellularity in cyanobacteria

    PubMed Central

    2011-01-01

    Background Cyanobacteria are one of the oldest and morphologically most diverse prokaryotic phyla on our planet. The early development of an oxygen-containing atmosphere approximately 2.45 - 2.22 billion years ago is attributed to the photosynthetic activity of cyanobacteria. Furthermore, they are one of the few prokaryotic phyla where multicellularity has evolved. Understanding when and how multicellularity evolved in these ancient organisms would provide fundamental information on the early history of life and further our knowledge of complex life forms. Results We conducted and compared phylogenetic analyses of 16S rDNA sequences from a large sample of taxa representing the morphological and genetic diversity of cyanobacteria. We reconstructed ancestral character states on 10,000 phylogenetic trees. The results suggest that the majority of extant cyanobacteria descend from multicellular ancestors. Reversals to unicellularity occurred at least 5 times. Multicellularity was established again at least once within a single-celled clade. Comparison to the fossil record supports an early origin of multicellularity, possibly as early as the "Great Oxygenation Event" that occurred 2.45 - 2.22 billion years ago. Conclusions The results indicate that a multicellular morphotype evolved early in the cyanobacterial lineage and was regained at least once after a previous loss. Most of the morphological diversity exhibited in cyanobacteria today —including the majority of single-celled species— arose from ancient multicellular lineages. Multicellularity could have conferred a considerable advantage for exploring new niches and hence facilitated the diversification of new lineages. PMID:21320320

  15. The Multiple Origins of Complex Multicellularity

    NASA Astrophysics Data System (ADS)

    Knoll, Andrew H.

    2011-05-01

    Simple multicellularity has evolved numerous times within the Eukarya, but complex multicellular organisms belong to only six clades: animals, embryophytic land plants, florideophyte red algae, laminarialean brown algae, and two groups of fungi. Phylogeny and genomics suggest a generalized trajectory for the evolution of complex multicellularity, beginning with the co-optation of existing genes for adhesion. Molecular channels to facilitate cell-cell transfer of nutrients and signaling molecules appear to be critical, as this trait occurs in all complex multicellular organisms but few others. Proliferation of gene families for transcription factors and cell signals accompany the key functional innovation of complex multicellular clades: differentiated cells and tissues for the bulk transport of oxygen, nutrients, and molecular signals that enable organisms to circumvent the physical limitations of diffusion. The fossil records of animals and plants document key stages of this trajectory.

  16. The multicellularity genes of dictyostelid social amoebas.

    PubMed

    Glöckner, Gernot; Lawal, Hajara M; Felder, Marius; Singh, Reema; Singer, Gail; Weijer, Cornelis J; Schaap, Pauline

    2016-01-01

    The evolution of multicellularity enabled specialization of cells, but required novel signalling mechanisms for regulating cell differentiation. Early multicellular organisms are mostly extinct and the origins of these mechanisms are unknown. Here using comparative genome and transcriptome analysis across eight uni- and multicellular amoebozoan genomes, we find that 80% of proteins essential for the development of multicellular Dictyostelia are already present in their unicellular relatives. This set is enriched in cytosolic and nuclear proteins, and protein kinases. The remaining 20%, unique to Dictyostelia, mostly consists of extracellularly exposed and secreted proteins, with roles in sensing and recognition, while several genes for synthesis of signals that induce cell-type specialization were acquired by lateral gene transfer. Across Dictyostelia, changes in gene expression correspond more strongly with phenotypic innovation than changes in protein functional domains. We conclude that the transition to multicellularity required novel signals and sensors rather than novel signal processing mechanisms. PMID:27357338

  17. The multicellularity genes of dictyostelid social amoebas

    PubMed Central

    Glöckner, Gernot; Lawal, Hajara M.; Felder, Marius; Singh, Reema; Singer, Gail; Weijer, Cornelis J.; Schaap, Pauline

    2016-01-01

    The evolution of multicellularity enabled specialization of cells, but required novel signalling mechanisms for regulating cell differentiation. Early multicellular organisms are mostly extinct and the origins of these mechanisms are unknown. Here using comparative genome and transcriptome analysis across eight uni- and multicellular amoebozoan genomes, we find that 80% of proteins essential for the development of multicellular Dictyostelia are already present in their unicellular relatives. This set is enriched in cytosolic and nuclear proteins, and protein kinases. The remaining 20%, unique to Dictyostelia, mostly consists of extracellularly exposed and secreted proteins, with roles in sensing and recognition, while several genes for synthesis of signals that induce cell-type specialization were acquired by lateral gene transfer. Across Dictyostelia, changes in gene expression correspond more strongly with phenotypic innovation than changes in protein functional domains. We conclude that the transition to multicellularity required novel signals and sensors rather than novel signal processing mechanisms. PMID:27357338

  18. Antimicrobial peptides of multicellular organisms

    NASA Astrophysics Data System (ADS)

    Zasloff, Michael

    2002-01-01

    Multicellular organisms live, by and large, harmoniously with microbes. The cornea of the eye of an animal is almost always free of signs of infection. The insect flourishes without lymphocytes or antibodies. A plant seed germinates successfully in the midst of soil microbes. How is this accomplished? Both animals and plants possess potent, broad-spectrum antimicrobial peptides, which they use to fend off a wide range of microbes, including bacteria, fungi, viruses and protozoa. What sorts of molecules are they? How are they employed by animals in their defence? As our need for new antibiotics becomes more pressing, could we design anti-infective drugs based on the design principles these molecules teach us?

  19. A Study of Barriers to Adult Self-Directed Learning

    ERIC Educational Resources Information Center

    Douglas, Edward

    2010-01-01

    Self-directed learning has contributed significantly to adult learners' personal and professional growth. Approximately 70% of adult learning is through a self-directed learning context (Heimstra, 2008). This quantitative correlational study involved an attempt to determine the nature of the relationship between situational, dispositional, and…

  20. Modeling Spaces for Self-Directed Learning at University Courses

    ERIC Educational Resources Information Center

    Pata, Kai

    2009-01-01

    This paper conceptualizes the theoretical framework of modeling learning spaces for self-directed learning at university courses. It binds together two ideas: (a) self-directed learners' common learning spaces may be characterized as abstract niches, (b) niche characteristics are collectively determined through individually perceived affordances.…

  1. Conditions Promoting Self-Directed Learning at the Workplace.

    ERIC Educational Resources Information Center

    Straka, Gerald A.

    Self-directed learning at work is becoming a major trend in training and organizational development. Referring to theoretical considerations in the domains of motivation and learning in disciplines beyond adult education, the concepts of interest, strategies, control, and evaluation seem appropriate to describe self-directed learning. Constructs…

  2. Processes of Change in Self-Directed Couple Relationship Education

    ERIC Educational Resources Information Center

    Wilson, Keithia L.; Halford, W. Kim

    2008-01-01

    The current study examined the learning processes involved in professionally supported self-directed couple relationship education (CRE). Fifty-nine couples completed Couple CARE, a systematic, self-directed CRE program designed in flexible delivery mode to be completed at home. Couples watched a DVD introducing key relationship ideas and skills…

  3. 42 CFR 441.452 - Self-direction: General.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 4 2014-10-01 2014-10-01 false Self-direction: General. 441.452 Section 441.452 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... must have in place, before electing the self-directed PAS option, personal care services through...

  4. 42 CFR 441.452 - Self-direction: General.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 4 2012-10-01 2012-10-01 false Self-direction: General. 441.452 Section 441.452 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... must have in place, before electing the self-directed PAS option, personal care services through...

  5. 42 CFR 441.452 - Self-direction: General.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 4 2013-10-01 2013-10-01 false Self-direction: General. 441.452 Section 441.452 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... must have in place, before electing the self-directed PAS option, personal care services through...

  6. Self-Directed Adult Learning: A Critical Paradigm.

    ERIC Educational Resources Information Center

    Brookfield, Stephen

    1984-01-01

    Argues that the propensity and capacity of many adults to conduct self-directed learning projects is now well proven, and that researchers should now infuse a spirit of self-critical scrutiny into this developing field of research. Advances four criticisms regarding the current state of self-directed learning research. (Author/CT)

  7. Development of the Self-Directed Learning Skills Scale

    ERIC Educational Resources Information Center

    Ayyildiz, Yildizay; Tarhan, Leman

    2015-01-01

    The purpose of this study was to develop a valid and reliable scale for assessing high school students' self-directed learning skills. Based on a literature review and data obtained from similar instruments, all skills related to self-directed learning were identified. Next, an item pool was prepared and administered to 255 students from various…

  8. Self-Directed Learning Readiness at General Motors Japan.

    ERIC Educational Resources Information Center

    Beitler, Michael A.

    Although self-directed learning (SDL) has been promoted by businesses as being needed by managers, traditional business schools have not promoted this type of learning. In addition, some adult learners are not ready for SDL, and some subjects (such as accounting) are not suitable for SDL. The concept of self-directed learning readiness (SDLR) can…

  9. Multicellularity makes somatic differentiation evolutionarily stable

    PubMed Central

    Wahl, Mary E.; Murray, Andrew W.

    2016-01-01

    Many multicellular organisms produce two cell lineages: germ cells, whose descendants produce the next generation, and somatic cells, which support, protect, and disperse the germ cells. This germ-soma demarcation has evolved independently in dozens of multicellular taxa but is absent in unicellular species. A common explanation holds that in these organisms, inefficient intercellular nutrient exchange compels the fitness cost of producing nonreproductive somatic cells to outweigh any potential benefits. We propose instead that the absence of unicellular, soma-producing populations reflects their susceptibility to invasion by nondifferentiating mutants that ultimately eradicate the soma-producing lineage. We argue that multicellularity can prevent the victory of such mutants by giving germ cells preferential access to the benefits conferred by somatic cells. The absence of natural unicellular, soma-producing species previously prevented these hypotheses from being directly tested in vivo: to overcome this obstacle, we engineered strains of the budding yeast Saccharomyces cerevisiae that differ only in the presence or absence of multicellularity and somatic differentiation, permitting direct comparisons between organisms with different lifestyles. Our strains implement the essential features of irreversible conversion from germ line to soma, reproductive division of labor, and clonal multicellularity while maintaining sufficient generality to permit broad extension of our conclusions. Our somatic cells can provide fitness benefits that exceed the reproductive costs of their production, even in unicellular strains. We find that nondifferentiating mutants overtake unicellular populations but are outcompeted by multicellular, soma-producing strains, suggesting that multicellularity confers evolutionary stability to somatic differentiation. PMID:27402737

  10. Multicellularity makes somatic differentiation evolutionarily stable.

    PubMed

    Wahl, Mary E; Murray, Andrew W

    2016-07-26

    Many multicellular organisms produce two cell lineages: germ cells, whose descendants produce the next generation, and somatic cells, which support, protect, and disperse the germ cells. This germ-soma demarcation has evolved independently in dozens of multicellular taxa but is absent in unicellular species. A common explanation holds that in these organisms, inefficient intercellular nutrient exchange compels the fitness cost of producing nonreproductive somatic cells to outweigh any potential benefits. We propose instead that the absence of unicellular, soma-producing populations reflects their susceptibility to invasion by nondifferentiating mutants that ultimately eradicate the soma-producing lineage. We argue that multicellularity can prevent the victory of such mutants by giving germ cells preferential access to the benefits conferred by somatic cells. The absence of natural unicellular, soma-producing species previously prevented these hypotheses from being directly tested in vivo: to overcome this obstacle, we engineered strains of the budding yeast Saccharomyces cerevisiae that differ only in the presence or absence of multicellularity and somatic differentiation, permitting direct comparisons between organisms with different lifestyles. Our strains implement the essential features of irreversible conversion from germ line to soma, reproductive division of labor, and clonal multicellularity while maintaining sufficient generality to permit broad extension of our conclusions. Our somatic cells can provide fitness benefits that exceed the reproductive costs of their production, even in unicellular strains. We find that nondifferentiating mutants overtake unicellular populations but are outcompeted by multicellular, soma-producing strains, suggesting that multicellularity confers evolutionary stability to somatic differentiation. PMID:27402737

  11. Iranian Clinical Nurses’ Readiness for Self-Directed Learning

    PubMed Central

    Malekian, Morteza; Ghiyasvandian, Sharzad; Cheraghi, Mohammad Ali; Hassanzadeh, Akbar

    2016-01-01

    Introduction: Clinical nurses are in need of being able to adapt to the ever-changing environment of clinical settings. The prerequisite for their successful adaptation is to be lifelong learners. An approach for making nurses lifelong learners is self-directed learning. Aims: This study was undertaken to evaluate a group of Iranian clinical nurses’ readiness for self-directed learning and its relationship with some of their personal characteristics. Methods: This cross-sectional descriptive study was conducted in 2014. A random sample of 314 nurses working in three hospitals affiliated to Isfahan Social Security Organization, Isfahan, Iran, was recruited to complete the Fisher’s Self-directed Learning Readiness Scale. Findings: In total, 279 nurses filled the scale completely. The mean of their readiness for self-directed learning was 162.50±14.11 (120–196). The correlation of self-directed learning readiness with age, gender, marital status, and university degree was not statistically significant. Conclusion: Most nurses had great readiness for self-directed learning. Accordingly, nursing policy-makers need to develop strategies for promoting their self-directed learning. Moreover, innovative teaching methods such as problem solving and problem-based learning should be employed to prepare nurses for effectively managing the complexities of their ever-changing work environment. PMID:26234971

  12. Bacterial Ventures into Multicellularity: Collectivism through Individuality.

    PubMed

    van Vliet, Simon; Ackermann, Martin

    2015-06-01

    Multicellular eukaryotes can perform functions that exceed the possibilities of an individual cell. These functions emerge through interactions between differentiated cells that are precisely arranged in space. Bacteria also form multicellular collectives that consist of differentiated but genetically identical cells. How does the functionality of these collectives depend on the spatial arrangement of the differentiated bacteria? In a previous issue of PLOS Biology, van Gestel and colleagues reported an elegant example of how the spatial arrangement of differentiated cells gives rise to collective behavior in Bacillus subtilus colonies, further demonstrating the similarity of bacterial collectives to higher multicellular organisms. PMID:26038821

  13. Bacterial Ventures into Multicellularity: Collectivism through Individuality

    PubMed Central

    van Vliet, Simon; Ackermann, Martin

    2015-01-01

    Multicellular eukaryotes can perform functions that exceed the possibilities of an individual cell. These functions emerge through interactions between differentiated cells that are precisely arranged in space. Bacteria also form multicellular collectives that consist of differentiated but genetically identical cells. How does the functionality of these collectives depend on the spatial arrangement of the differentiated bacteria? In a previous issue of PLOS Biology, van Gestel and colleagues reported an elegant example of how the spatial arrangement of differentiated cells gives rise to collective behavior in Bacillus subtilus colonies, further demonstrating the similarity of bacterial collectives to higher multicellular organisms. PMID:26038821

  14. Receptor tyrosine kinase targeting in multicellular spheroids.

    PubMed

    Breslin, Susan; O'Driscoll, Lorraine

    2015-01-01

    While growing cells as a monolayer is the traditional method for cell culture, the incorporation of multicellular spheroids into experimental design is becoming increasingly popular. This is due to the understanding that cells grown as spheroids tend to replicate the in vivo situation more reliably than monolayer cells. Thus, the use of multicellular spheroids may be more clinically relevant than monolayer cell cultures. Here, we describe methods for multicellular 3D spheroid generation that may be used to provide samples for receptor tyrosine kinase (and other protein) detection. Methods described include the forced-floating poly-HEMA method, the hanging-drop method, and the use of ECM to form multicellular 3D spheroids. PMID:25319898

  15. The Evolution of Multicellular Plants and Animals.

    ERIC Educational Resources Information Center

    Valentine, James W.

    1978-01-01

    Traces the evolution of unicellular organisms to the multi-cellular plants and animals in existence today. Major events are depicted in a geologic timetable. Organisms, extinct and recent, are classified by taxonomic group. (MA)

  16. The simplest integrated multicellular organism unveiled.

    PubMed

    Arakaki, Yoko; Kawai-Toyooka, Hiroko; Hamamura, Yuki; Higashiyama, Tetsuya; Noga, Akira; Hirono, Masafumi; Olson, Bradley J S C; Nozaki, Hisayoshi

    2013-01-01

    Volvocine green algae represent the "evolutionary time machine" model lineage for studying multicellularity, because they encompass the whole range of evolutionary transition of multicellularity from unicellular Chlamydomonas to >500-celled Volvox. Multicellular volvocalean species including Gonium pectorale and Volvox carteri generally have several common morphological features to survive as integrated multicellular organisms such as "rotational asymmetry of cells" so that the cells become components of the individual and "cytoplasmic bridges between protoplasts in developing embryos" to maintain the species-specific form of the multicellular individual before secretion of new extracellular matrix (ECM). However, these morphological features have not been studied in the four-celled colonial volvocine species Tetrabaena socialis that is positioned in the most basal lineage within the colonial or multicellular volvocine greens. Here we established synchronous cultures of T. socialis and carried out immunofluorescence microscopic and ultrastructural observations to elucidate these two morphological attributes. Based on immunofluorescence microscopy, four cells of the mature T. socialis colony were identical in morphology but had rotational asymmetry in arrangement of microtubular rootlets and separation of basal bodies like G. pectorale and V. carteri. Ultrastructural observations clearly confirmed the presence of cytoplasmic bridges between protoplasts in developing embryos of T. socialis even after the formation of new flagella in each daughter protoplast within the parental ECM. Therefore, these two morphological attributes might have evolved in the common four-celled ancestor of the colonial volvocine algae and contributed to the further increase in cell number and complexity of the multicellular individuals of this model lineage. T. socialis is one of the simplest integrated multicellular organisms in which four identical cells constitute the individual. PMID

  17. The Simplest Integrated Multicellular Organism Unveiled

    PubMed Central

    Arakaki, Yoko; Kawai-Toyooka, Hiroko; Hamamura, Yuki; Higashiyama, Tetsuya; Noga, Akira; Hirono, Masafumi; Olson, Bradley J. S. C.; Nozaki, Hisayoshi

    2013-01-01

    Volvocine green algae represent the “evolutionary time machine” model lineage for studying multicellularity, because they encompass the whole range of evolutionary transition of multicellularity from unicellular Chlamydomonas to >500-celled Volvox. Multicellular volvocalean species including Gonium pectorale and Volvox carteri generally have several common morphological features to survive as integrated multicellular organisms such as “rotational asymmetry of cells” so that the cells become components of the individual and “cytoplasmic bridges between protoplasts in developing embryos” to maintain the species-specific form of the multicellular individual before secretion of new extracellular matrix (ECM). However, these morphological features have not been studied in the four-celled colonial volvocine species Tetrabaena socialis that is positioned in the most basal lineage within the colonial or multicellular volvocine greens. Here we established synchronous cultures of T. socialis and carried out immunofluorescence microscopic and ultrastructural observations to elucidate these two morphological attributes. Based on immunofluorescence microscopy, four cells of the mature T. socialis colony were identical in morphology but had rotational asymmetry in arrangement of microtubular rootlets and separation of basal bodies like G. pectorale and V. carteri. Ultrastructural observations clearly confirmed the presence of cytoplasmic bridges between protoplasts in developing embryos of T. socialis even after the formation of new flagella in each daughter protoplast within the parental ECM. Therefore, these two morphological attributes might have evolved in the common four-celled ancestor of the colonial volvocine algae and contributed to the further increase in cell number and complexity of the multicellular individuals of this model lineage. T. socialis is one of the simplest integrated multicellular organisms in which four identical cells constitute the

  18. Beyond the classroom: self-direction in professional learning.

    PubMed Central

    Mayfield, M K

    1993-01-01

    Against the backdrop of a rapidly changing profession, the context for professional thinking among medical librarians is changing. Competent performance increasingly is linked with the educational efforts of self-directed adult learners. This paper examines strategies that facilitate self-direction, including skills development, organizational learning, learner-based decision making, and alternative teaching models. The analysis provides the basis for a recommended agenda for redesign and development of educational programs. PMID:8251979

  19. Fibroblast spheroids as a model to study sustained fibroblast quiescence and their crosstalk with tumor cells.

    PubMed

    Salmenperä, Pertteli; Karhemo, Piia-Riitta; Räsänen, Kati; Laakkonen, Pirjo; Vaheri, Antti

    2016-07-01

    Stromal fibroblasts have an important role in regulating tumor progression. Normal and quiescent fibroblasts have been shown to restrict and control cancer cell growth, while cancer-associated, i. e. activated fibroblasts have been shown to enhance proliferation and metastasis of cancer cells. In this study we describe generation of quiescent fibroblasts in multicellular spheroids and their effects on squamous cell carcinoma (SCC) growth in soft-agarose and xenograft models. Quiescent phenotype of fibroblasts was determined by global down-regulation of expression of genes related to cell cycle and increased expression of p27. Interestingly, microarray analysis showed that fibroblast quiescence was associated with similar secretory phenotype as seen in senescence and they expressed senescence-associated-β-galactosidase. Quiescent fibroblasts spheroids also restricted the growth of RT3 SCC cells both in soft-agarose and xenograft models unlike proliferating fibroblasts. Restricted tumor growth was associated with marginally increased tumor cell senescence and cellular differentiation, showed with senescence-associated-β-galactosidase and cytokeratin 7 staining. Our results show that the fibroblasts spheroids can be used as a model to study cellular quiescence and their effects on cancer cell progression. PMID:27177832

  20. Situational Teaching: Fostering Self-Direction in the Classroom.

    ERIC Educational Resources Information Center

    Scobie, Robert

    1983-01-01

    For effective teaching, the author asserts, student self-direction must be matched to an appropriate degree of teacher direction and both adjusted for group dynamics of the classroom. Accounting for these three levels of activity, a schematic analysis is drawn of the total teaching situation, and strategies are suggested that adapt teaching style…

  1. Self-Directed Learning Readiness and Occupational Categories.

    ERIC Educational Resources Information Center

    Durr, Richard; And Others

    1996-01-01

    Managers and nonmanagers completed the Self-Directed Learning (SDL) Readiness Scale (n=303, 30% response); Most of the nine occupational categories were above average in SDL readiness; sales occupations had the highest mean score; managers scored significantly higher than nonmanagers. Low scores for clerical and manufacturing groups suggest a need…

  2. Cognitive Self-Direction: Methodology for Teacher Education.

    ERIC Educational Resources Information Center

    Payne, Beverly D.; Manning, Brenda H.

    1991-01-01

    Describes the methodology for teaching cognitive self-direction (CSD) to preservice teachers, presenting an overview of the CSD model. The CSD curriculum model includes productive strategies such as modeling plus self-verbalization (goal-setting, guiding, and reinforcing behaviors). Benefits to preservice teacher education include improved lesson…

  3. A Cognitive Self-Direction Model for Teacher Education.

    ERIC Educational Resources Information Center

    Manning, Brenda H.; Payne, Beverly D.

    1989-01-01

    A literature review of cognitive self-direction (CSD), a description of the preservice CSD curriculum model, and an overview of CSD methodology are provided. Benefits of CSD type instruction for preservice teachers include more internal locus of control orientations, less anxiety, and improved lesson planning, classroom performance, and…

  4. Moderate Weight Loss: A Self-Directed Protocol for Women

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was performed to examine the efficacy of a self-directed diet and physical activity program as a method for weight loss in women. Forty-two hyperlipidemic overweight and obese women were recruited to participate in this twenty-four week weight intervention study. The women’s ages ranged...

  5. Self-Directed Support Policy: Challenges and Possible Solutions

    ERIC Educational Resources Information Center

    Harkes, Mary A.; Brown, Michael; Horsburgh, Dorothy

    2014-01-01

    A systematic literature review was conducted between September 2010 and April 2011 and published earlier in this journal, paper 1. The findings indicated that few studies of Self-Directed Support focused specifically on people with intellectual disabilities. The range of individuals' ability and distinction between adults with or without…

  6. Self-Directed Learning. Myths and Realities No. 3.

    ERIC Educational Resources Information Center

    Kerka, Sandra

    In one school of thought, self-directed learning (SDL) is based in the autonomous, independent individual who chooses to undertake learning for personal growth. However, another school of thought stresses the social construction of knowledge and the social context of learning. Some writers challenge the exclusive emphasis on the autonomous self…

  7. Personal Learning Environments: A Solution for Self-Directed Learners

    ERIC Educational Resources Information Center

    Haworth, Ryan

    2016-01-01

    In this paper I discuss "personal learning environments" and their diverse benefits, uses, and implications for life-long learning. Personal Learning Environments (PLEs) are Web 2.0 and social media technologies that enable individual learners the ability to manage their own learning. Self-directed learning is explored as a foundation…

  8. Self-Directed Learning in Adulthood: A Literature Review.

    ERIC Educational Resources Information Center

    Owen, T. Ross

    Self-directed learning (SDL) is among the most productive areas of research in adult education. Malcolm S. Knowles is credited with a comprehensive synthesis of adult teaching and adult learning principles. Andragogy, the art and science of helping adults learn, lies at the heart of Knowles' work. Lucy M. Guglielmino theorized regarding the…

  9. The Self-Directed Learning of Women with Breast Cancer.

    ERIC Educational Resources Information Center

    Rager, Kathleen B.

    2003-01-01

    Self-directed learning experiences of 13 women with breast cancer were explored. Learning motivations included overcoming fear, needing to understand, and being able to make informed choices. They used print, Internet, networks, and support groups. They had difficulties locating resources and dealing with emotions. Learning outcomes included…

  10. A Study of Self-Directed Professionals of High Attainment.

    ERIC Educational Resources Information Center

    Bouchard, Paul

    The determinants of self-directed learning (SDL) among professionals of high attainment were examined through open-ended, semidirected interviews with a purposeful sample of eight professional men and women who have acquired identifiable, high-level professional knowledge/skills typically taught in postsecondary learning institutions without ever…

  11. The Role of Intrapersonal Intelligence in Self Directed Learning

    ERIC Educational Resources Information Center

    Sellars, Maura

    2006-01-01

    Supporting students to be self-directed learners in classrooms is currently more important than it has ever been in the past. The rapidly changing nature of society, the demands of the "new economy" and the contemporary understanding of life long learning have combined to highlight the need for students to be increasingly independent learners.…

  12. Analysis of Self-Directed Mastery Learning of Honors Physics

    ERIC Educational Resources Information Center

    Athens, Wendy

    2011-01-01

    Self-directed learning (SDL) is an important life skill in a knowledge-based society and prepares students to persist, manage their time and resources, use logic to construct their knowledge, argue their views, and collaborate. The purpose of this study was to facilitate mastery of physics concepts through self-directedness in formative testing…

  13. Self-Directed Informal Learning: A Case Study

    ERIC Educational Resources Information Center

    Hanstock, Robyn

    2004-01-01

    This case study examines the life journey of a self-directed adult learner who has made remarkable achievements in overcoming a difficult educational beginning in early childhood, as well as personal trauma in adulthood. The subject has shown determination in seeking out his own opportunities to learn in spite of major drawbacks, chief of which…

  14. Self-Directed Lifelong Learning in Hybrid Learning Configurations

    ERIC Educational Resources Information Center

    Cremers, Petra H. M.; Wals, Arjen E. J.; Wesselink, Renate; Nieveen, Nienke; Mulder, Martin

    2014-01-01

    Present-day students are expected to be lifelong learners throughout their working life. Higher education must therefore prepare students to self-direct their learning beyond formal education, in real-life working settings. This can be achieved in so-called hybrid learning configurations in which working and learning are integrated. In such a…

  15. Self-Directed Learning: A Tool for Lifelong Learning

    ERIC Educational Resources Information Center

    Boyer, Stefanie L.; Edmondson, Diane R.; Artis, Andrew B.; Fleming, David

    2014-01-01

    A meta-analytic review of self-directed learning (SDL) research over 30 years, five countries, and across multiple academic disciplines is used to explore its relationships with five key nomologically related constructs for effective workplace learning. The meta-analysis revealed positive relationships between SDL and internal locus of control,…

  16. Implementing Self-Directed Work Teams at a College Newspaper

    ERIC Educational Resources Information Center

    de Pillis, Emmeline; Parsons, Blake

    2013-01-01

    The problem: Motivating and retaining staff had become an ongoing problem at the student newspaper. Student staffers would quit abruptly when overwhelmed or dissatisfied, leaving the newspaper with critical positions vacant. This affected the performance of the newspaper. Method: The newspaper was organized into self directed work teams (SDWTs).…

  17. "Employee--Develop Yourself!" Experiences of Self-Directed Learners.

    ERIC Educational Resources Information Center

    Stansfield, Lynda Margaret

    1997-01-01

    Participants in management development (n=714) identified the most and least useful aspects of the program. Many felt that self-directed learning was demanding but led to deeper learning. At the same time, they showed discomfort with the tutor's role as facilitator and the lack of structure. Time pressures were major barriers. (SK)

  18. Self-Directed Writing: Giving Voice to Student Writers

    ERIC Educational Resources Information Center

    Lovejoy, Kim Brian

    2009-01-01

    Self-directed writing is an opportunity for teachers to write with their students, and it is writing that ultimately ends up in the student's portfolio at mid-term and end of term. It is one component of a structured writing class in which students also do other writing assignments. It is important for teachers to communicate their expectations of…

  19. Reorienting Self-Directed Learning for the Creative Digital Era

    ERIC Educational Resources Information Center

    Karakas, Fahri; Manisaligil, Alperen

    2012-01-01

    Purpose: The purpose of this paper is to identify the new role that human resource developers play in the globally connected workplace. Towards that end, this paper explores the changing landscape of self-directed learning (SDL) within the digital ecosystem based on the concept of World 2.0. Design/methodology/approach: This paper reviews and…

  20. Origins of multicellular evolvability in snowflake yeast.

    PubMed

    Ratcliff, William C; Fankhauser, Johnathon D; Rogers, David W; Greig, Duncan; Travisano, Michael

    2015-01-01

    Complex life has arisen through a series of 'major transitions' in which collectives of formerly autonomous individuals evolve into a single, integrated organism. A key step in this process is the origin of higher-level evolvability, but little is known about how higher-level entities originate and gain the capacity to evolve as an individual. Here we report a single mutation that not only creates a new level of biological organization, but also potentiates higher-level evolvability. Disrupting the transcription factor ACE2 in Saccharomyces cerevisiae prevents mother-daughter cell separation, generating multicellular 'snowflake' yeast. Snowflake yeast develop through deterministic rules that produce geometrically defined clusters that preclude genetic conflict and display a high broad-sense heritability for multicellular traits; as a result they are preadapted to multicellular adaptation. This work demonstrates that simple microevolutionary changes can have profound macroevolutionary consequences, and suggests that the formation of clonally developing clusters may often be the first step to multicellularity. PMID:25600558

  1. Limits to Chemically Guided Multicellular Migration

    NASA Astrophysics Data System (ADS)

    Varennes, Julien; Han, Bumsoo; Mugler, Andrew

    Collective cell migration in response to a chemical cue requires both multicellular sensing of chemical gradients and coordinated mechanical action. Examples from morphogenesis and cancer metastasis demonstrate that clusters of migratory cells are extremely sensitive, responding to gradients of less than 1% difference in chemical concentration across a cell body. While the limits to multicellular sensing are becoming known, the ensuing consequences for coherent migration remain poorly understood. We develop a model of multicellular sensing and migration based on the cellular Potts model. Multicellular sensing of noisy chemical gradients is modeled as a process of local excitation and global inhibition (LEGI) among communicating cells. The output of the sensing process is coupled to individual cells' polarization to model migratory behavior. We find that larger clusters of cells detect the gradient direction with higher precision and thus achieve stronger polarization bias. At the same time, larger clusters are also accompanied by less coherent collective motion. The trade-off between these two effects leads to an optimally efficient cluster size. We discuss how our results relate to cancer metastasis.

  2. Increasing Readiness for Self-Directed Learning: A Facilitator's Manual for Ten Self-Directed Learning Group Modules for Adults.

    ERIC Educational Resources Information Center

    Rutland, Adonna M.; Guglielmino, Lucy M.

    This manual was prepared for use by adult education teachers in facilitating a self-directed learning (SDL) group for students based on the modules described in the manual. The SDL group involves 10 sessions with specific objectives and activities for each session. Following an introduction, the manual is organized in five additional sections. The…

  3. Self-directed Learning to Educate Medical Educators. Part 1: How Do We Use Self-directed Learning?

    ERIC Educational Resources Information Center

    Hammond, Merryl; Collins, Rob

    1987-01-01

    Described are seven steps used to help self-directed learners to work through the Diploma in Primary Health Care (Education) course at the University of Witwatersrand. The steps are: situation analysis; compilation of a competency profile; self-assessment of learning needs; writing learning objectives; compilation of a learning agreement;…

  4. Developing the Self-Directed Learning Instructional Model to Enhance English Reading Ability and Self-Directed Learning of Undergraduate Students

    ERIC Educational Resources Information Center

    Wichadee, Saovapa

    2011-01-01

    The purposes of this study were to develop the instructional model for enhancing self-directed learning skills of Bangkok University students, study the impacts of the model on their English reading comprehension and self-directed learning ability as well as explore their opinion towards self-directed learning. The model development process…

  5. Analysis of self-directed mastery learning of honors physics

    NASA Astrophysics Data System (ADS)

    Athens, Wendy

    Self-directed learning (SDL) is an important life skill in a knowledge-based society and prepares students to persist, manage their time and resources, use logic to construct their knowledge, argue their views, and collaborate. The purpose of this study was to facilitate mastery of physics concepts through self-directedness in formative testing with feedback, a choice of learning activities, and multiple forms of support. This study was conducted within two sections of honors physics at a private high school (N=24). Students' learning activity choices, time investments, and perceptions (assessed through a post survey) were tracked and analyzed. SDL readiness was linked to success in mastering physics concepts. The three research questions pursued in this study were: What SDL activities did honors physics students choose in their self-directed mastery learning environment? How many students achieved concept mastery and how did they spend their time? Did successful and unsuccessful students perceive the self-directed mastery learning environment differently? Only seven of 24 students were successful in passing the similar concept-based unit tests within four tries, and these seven students were separated into a "successful" group and the other 17 into an "unsuccessful" group. Differences between the two groups were analyzed. A profile of a self-directed secondary honors physics student emerged. A successful self-directed student invested more time learning from activities rather than simply completing them, focused on learning concepts more than rote operations, intentionally selected activities to fill in gaps of knowledge and practice concepts, actively constructed knowledge into a cognitive framework, engaged in academic discourse with instructor and peers as they made repeated attempts to master content and pass the test given constructive feedback, used a wide variety of learning resources, and managed their workload to meet deadlines. This capstone study found

  6. Self-directed control of pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Stark, E. F.; Laube, S. J. P.

    1993-10-01

    Implementation of self-directed control of pulsed laser deposition (PLD) requires actuators, sensors, and a materials and processing knowledge base. Improvements in quality and reproducibility of material deposits are achieved by driving the process toward desired operating regions. Empirical relationships are determined experimentally to describe the complex dynamical interactions of laser parameters. Feedback control based on this description can then be implemented to reduce process disorder and effectively produce consistent coatings with desired properties.

  7. Extracellular signaling and multicellularity in Bacillus subtilis.

    PubMed

    Shank, Elizabeth Anne; Kolter, Roberto

    2011-12-01

    Bacillus subtilis regulates its ability to differentiate into distinct, co-existing cell types in response to extracellular signaling molecules produced either by itself, or present in its environment. The production of molecules by B. subtilis cells, as well as their response to these signals, is not uniform across the population. There is specificity and heterogeneity both within genetically identical populations as well as at the strain-level and species-level. This review will discuss how extracellular signaling compounds influence B. subtilis multicellularity with regard to matrix-producing cannibal differentiation, germination, and swarming behavior, as well as the specificity of the quorum-sensing peptides ComX and CSF. It will also highlight how imaging mass spectrometry can aid in identifying signaling compounds and contribute to our understanding of the functional relationship between such compounds and multicellular behavior. PMID:22024380

  8. Extracellular signaling and multicellularity in Bacillus subtilis

    PubMed Central

    Anne Shank, Elizabeth; Kolter, Roberto

    2012-01-01

    Summary Bacillus subtilis regulates its ability to differentiate into distinct, co-existing cell types in response to extracellular signaling molecules produced either by itself, or present in its environment. The production of molecules by B. subtilis cells, as well as their response to these signals, is not uniform across the population. There is specificity and heterogeneity both within genetically identical populations as well as at the strain- and species-levels. This review will discuss how extracellular signaling compounds influence B. subtilis multicellularity with regard to matrix-producing cannibal differentiation, germination, and swarming behavior, as well as the specificity of the quorum-sensing peptides ComX and CSF. It will also highlight how imaging mass spectrometry can aid in identifying signaling compounds and contribute to our understanding of the functional relationship between such compounds and multicellular behavior. PMID:22024380

  9. Ontogenetic growth of multicellular tumor spheroids

    NASA Astrophysics Data System (ADS)

    Condat, C. A.; Menchón, S. A.

    2006-11-01

    In ontogenetic growth models, the basal metabolic rate is usually assumed to depend on the individual mass following a power law. Here it is shown that, in the case of multicellular tumor spheroids, the emergence of a necrotic core invalidates this assumption. The implications of this result for spheroid growth are discussed, and a procedure to determine the growth parameters using macroscopic measurements is proposed.

  10. Cooperation, clumping and the evolution of multicellularity.

    PubMed

    Biernaskie, Jay M; West, Stuart A

    2015-08-22

    The evolution of multicellular organisms represents one of the major evolutionary transitions in the history of life. A potential advantage of forming multicellular clumps is that it provides an efficiency benefit to pre-existing cooperation, such as the production of extracellular 'public goods'. However, this is complicated by the fact that cooperation could jointly evolve with clumping, and clumping could have multiple consequences for the evolution of cooperation. We model the evolution of clumping and a cooperative public good, showing that (i) when considered separately, both clumping and public goods production gradually increase with increasing genetic relatedness; (ii) in contrast, when the traits evolve jointly, a small increase in relatedness can lead to a major shift in evolutionary outcome—from a non-clumping state with low public goods production to a cooperative clumping state with high values of both traits; (iii) high relatedness makes it easier to get to the cooperative clumping state and (iv) clumping can be inhibited when it increases the number of cells that the benefits of cooperation must be shared with, but promoted when it increases relatedness between those cells. Overall, our results suggest that public goods sharing can facilitate the formation of well-integrated cooperative clumps as a first step in the evolution of multicellularity. PMID:26246549

  11. Collective Chemotaxis through Noisy Multicellular Gradient Sensing

    NASA Astrophysics Data System (ADS)

    Varennes, Julien; Han, Bumsoo; Mugler, Andrew

    2016-08-01

    Collective cell migration in response to a chemical cue occurs in many biological processes such as morphogenesis and cancer metastasis. Clusters of migratory cells in these systems are capable of responding to gradients of less than 1% difference in chemical concentration across a cell length. Multicellular systems are extremely sensitive to their environment and while the limits to multicellular sensing are becoming known, how this information leads to coherent migration remains poorly understood. We develop a computational model of multicellular sensing and migration in which groups of cells collectively measure noisy chemical gradients. The output of the sensing process is coupled to individual cells polarization to model migratory behavior. Through the use of numerical simulations, we find that larger clusters of cells detect the gradient direction with higher precision and thus achieve stronger polarization bias, but larger clusters also induce more drag on collective motion. The trade-off between these two effects leads to an optimal cluster size for most efficient migration. We discuss how our model could be validated using simple, phenomenological experiments.

  12. Collective Chemotaxis through Noisy Multicellular Gradient Sensing.

    PubMed

    Varennes, Julien; Han, Bumsoo; Mugler, Andrew

    2016-08-01

    Collective cell migration in response to a chemical cue occurs in many biological processes such as morphogenesis and cancer metastasis. Clusters of migratory cells in these systems are capable of responding to gradients of <1% difference in chemical concentration across a cell length. Multicellular systems are extremely sensitive to their environment, and although the limits to multicellular sensing are becoming known, how this information leads to coherent migration remains poorly understood. We develop a computational model of multicellular sensing and migration in which groups of cells collectively measure noisy chemical gradients. The output of the sensing process is coupled to the polarization of individual cells to model migratory behavior. Through the use of numerical simulations, we find that larger clusters of cells detect the gradient direction with higher precision and thus achieve stronger polarization bias, but larger clusters also induce more drag on collective motion. The trade-off between these two effects leads to an optimal cluster size for most efficient migration. We discuss how our model could be validated using simple, phenomenological experiments. PMID:27508447

  13. Development of Three-Dimensional Multicellular Tissue-Like Constructs for Mutational Analysis Using Macroporous Microcarriers

    NASA Technical Reports Server (NTRS)

    Jordan, Jacqueline A.; Fraga, Denise N.; Gonda, Steve R.

    2002-01-01

    A three-dimensional (3-D), tissue-like model was developed for the genotoxic assessment of space environment. In previous experiments, we found that culturing mammalian cells in a NASA-designed bioreactor, using Cytodex-3 beads as a scaffold, generated 3-D multicellular spheroids. In an effort to generate scaffold-free spheroids, we developed a new 3-D tissue-like model by coculturing fibroblast and epithelial cell in a NASA bioreactor using macroporous Cultispher-S(TradeMark) microcarriers. Big Blue(Registered Trademark) Rat 2(Lambda) fibroblasts, genetically engineered to contain multiple copies (>60 copies/cell) of the Lac I target gene, were cocultured with radio-sensitive human epithelial cells, H184F5. Over an 8-day period, samples were periodically examined by microscopy and histology to confirm cell attachment, growth, and viability. Immunohistochemistry and western analysis were used to evaluate the expression of specific cytoskeletal and adhesion proteins. Key cell culture parameters (glucose, pH, and lactate concentrations) were monitored daily. Controls were two-dimensional mono layers of fibroblast or epithelial cells cultured in T-flasks. Analysis of 3-D spheroids from the bioreactor suggests fibroblast cells attached to and completely covered the bead surface and inner channels by day 3 in the bioreactor. Treatment of the 3-day spheroids with dispase II dissolved the Cultisphers(TradeMark) and produced multicellular, bead-less constructs. Immunohistochemistry confirmed the presence of vi.mentin, cytokeratin and E-cadherin in treated spheroids. Examination of the dispase II treated spheroids with transmission electron microscopy (TEM) also showed the presence of desmosomes. These results suggest that the controlled enzymatic degradation of an artificial matrix in the low shear environment of the NASA-designed bioreactor can produce 3-D tissue-like spheroids. 2

  14. Self-directed Learning and Its Impact on Menopausal Symptoms

    PubMed Central

    Yazdkhasti, Mansoureh; Keshavarz, Maryam; Mahmoodi, Zohreh; Hosseini, Agha Fatemeh

    2014-01-01

    Background: One of the main criteria to verify the effectiveness of a health training program is to measure quality of life in menopausal women. Objectives: Hence the aim of this review was to evaluate the effects of self-directed learning (SDL) on MENQOl. Patients and Methods: The present single blind field study was conducted in Saadatmandi Health Center of Robat Karim (Iran, Southwest of Tehran Province) from August to December 2010. One handred and ten menopausal women were selected using convenience sampling method and then divided into two experimental (Self-directed Learning) and control groups of 55 each. Four manuals were developed to guide the women in the experimental group containing practical ways to treat menopausal symptoms. They were distributed among the participants for four weeks on a specific day. Menopausal Specific Quality of Life Questionnaire (MENQOL) was used to determine and compare quality of life scores of these women (before and three months after intervention sessions). The control group did not receive any intervention. Statistical analysis was performed by SPSS/16 software using Kolmogorov-Sminov, ANOVA, independent paired t test and Chi-square test. Results: There were significant statistical differences between two groups regarding the age of subjects; age of menopause; economic, educational and employment status; number of dead and living children; BMI and vasomotor, physical, sexual and psycho-social postmenopausal symptoms. The implementation of Self-directed Learning (SDL) model leads to a significant statistical difference in scores of vasomotor symptoms (16.32 ± 5.92 to 13.26 ± 5.31), psychosocial symptoms (34.8 ± 11 to 27.18 ± 10.83), physical symptoms (75.02 ± 18.07 to 61.42 ± 15.49), sexual symptoms (15.36 ± 6.10 to 12.00 ± 4.97) and the overall score for quality of life (141.5 ± 41.09 to 113.86 ± 36.6) (P < 0.001). No significant changes were found in the QOL scores of the control group. Conclusions

  15. Chinese baccalaureate nursing students' readiness for self-directed learning.

    PubMed

    Yuan, Hao Bin; Williams, Beverly A; Fang, Jin Bo; Pang, Dong

    2012-05-01

    This descriptive cross-sectional study was conducted with 536 Chinese nursing students to explore students' readiness for self-directed learning (SDL). The Self-Directed Learning Readiness (SDLR) Scale for nursing education (Chinese translation version) was used. The value of the content validity index tested by five experts was 0.915. A measure of internal consistency (Cronbach's alpha) was 0.925 on the total scale. Students possessed readiness for SDL with a mean score of 157.72 (S.D.=15.08, 62.3% in high level, and 37.7% in low level). The attributes of Chinese students, such as a strong sense of responsibility and perseverance, due diligence and rigorous self-discipline, enable students to take the initiative and responsibility for their own learning. The existing variation in students' readiness for SDL is helpful in identifying student characteristics that might be used to modify learning activities for these students. Senior students had higher scores for SDLR than junior students. This finding likely reflects the maturational process of developing self-directedness. Promoting SDL skills is a challenging process for faculty members and students. It is helpful if nurse educators assess the learning styles and preferences of their students in order to determine the level of SDL activities to include from year to year in the curriculum. PMID:21458116

  16. Cell adhesion, multicellular morphology, and magnetosome distribution in the multicellular magnetotactic prokaryote Candidatus Magnetoglobus multicellularis.

    PubMed

    Abreu, Fernanda; Silva, Karen Tavares; Leão, Pedro; Guedes, Iame Alves; Keim, Carolina Neumann; Farina, Marcos; Lins, Ulysses

    2013-06-01

    Candidatus Magnetoglobus multicellularis is an uncultured magnetotactic multicellular prokaryote composed of 17-40 Gram-negative cells that are capable of synthesizing organelles known as magnetosomes. The magnetosomes of Ca. M. multicellularis are composed of greigite and are organized in chains that are responsible for the microorganism's orientation along magnetic field lines. The characteristics of the microorganism, including its multicellular life cycle, magnetic field orientation, and swimming behavior, and the lack of viability of individual cells detached from the whole assembly, are considered strong evidence for the existence of a unique multicellular life cycle among prokaryotes. It has been proposed that the position of each cell within the aggregate is fundamental for the maintenance of its distinctive morphology and magnetic field orientation. However, the cellular organization of the whole organism has never been studied in detail. Here, we investigated the magnetosome organization within a cell, its distribution within the microorganism, and the intercellular relationships that might be responsible for maintaining the cells in the proper position within the microorganism, which is essential for determining the magnetic properties of Ca. M. multicellularis during its life cycle. The results indicate that cellular interactions are essential for the determination of individual cell shape and the magnetic properties of the organism and are likely directly associated with the morphological changes that occur during the multicellular life cycle of this species. PMID:23551897

  17. Self-Directed and Incidental Learning. Symposium 26. [Concurrent Symposium Session at AHRD Annual Conference, 2000.

    ERIC Educational Resources Information Center

    2000

    This packet contains three papers on self-directed and incidental learning from a symposium on human resource development (HRD). The first paper, "Self-Directed Learning for Supervisory Development" (Judy O'Neil, Maria Lamattina), reports on a study that looks at what research says needs to be in place to engage workers in self-directed learning…

  18. Analysis of Self-Directed Learning upon Student of Mathematics Education Study Program

    ERIC Educational Resources Information Center

    Kleden, Maria Agustina

    2015-01-01

    Various studies have rendered self-directed learning disposition to be significant in the learning of mathematics, however several previous studies have pointed the level of self-directed learning disposition to be at a low point. This research is aimed to enhance self-directed learning through implementing a metacognitive strategy in learning…

  19. The Influence of Complexity and Uncertainty on Self-Directed Team Learning

    ERIC Educational Resources Information Center

    Gray, David

    2012-01-01

    To help increase the effectiveness of self-directed teams, this paper studies the attitudes and behaviour of self-directed team members during the course of a computer simulated marketing strategy game. Self-directed teams are used widely throughout organisations yet receive little scrutiny when they undertake a task which is subject to conditions…

  20. Aneuploidy underlies a multicellular phenotypic switch

    PubMed Central

    Tan, Zhihao; Hays, Michelle; Cromie, Gareth A.; Jeffery, Eric W.; Scott, Adrian C.; Ahyong, Vida; Sirr, Amy; Skupin, Alexander; Dudley, Aimée M.

    2013-01-01

    Although microorganisms are traditionally used to investigate unicellular processes, the yeast Saccharomyces cerevisiae has the ability to form colonies with highly complex, multicellular structures. Colonies with the “fluffy” morphology have properties reminiscent of bacterial biofilms and are easily distinguished from the “smooth” colonies typically formed by laboratory strains. We have identified strains that are able to reversibly toggle between the fluffy and smooth colony-forming states. Using a combination of flow cytometry and high-throughput restriction-site associated DNA tag sequencing, we show that this switch is correlated with a change in chromosomal copy number. Furthermore, the gain of a single chromosome is sufficient to switch a strain from the fluffy to the smooth state, and its subsequent loss to revert the strain back to the fluffy state. Because copy number imbalance of six of the 16 S. cerevisiae chromosomes and even a single gene can modulate the switch, our results support the hypothesis that the state switch is produced by dosage-sensitive genes, rather than a general response to altered DNA content. These findings add a complex, multicellular phenotype to the list of molecular and cellular traits known to be altered by aneuploidy and suggest that chromosome missegregation can provide a quick, heritable, and reversible mechanism by which organisms can toggle between phenotypes. PMID:23812752

  1. Aneuploidy underlies a multicellular phenotypic switch.

    PubMed

    Tan, Zhihao; Hays, Michelle; Cromie, Gareth A; Jeffery, Eric W; Scott, Adrian C; Ahyong, Vida; Sirr, Amy; Skupin, Alexander; Dudley, Aimée M

    2013-07-23

    Although microorganisms are traditionally used to investigate unicellular processes, the yeast Saccharomyces cerevisiae has the ability to form colonies with highly complex, multicellular structures. Colonies with the "fluffy" morphology have properties reminiscent of bacterial biofilms and are easily distinguished from the "smooth" colonies typically formed by laboratory strains. We have identified strains that are able to reversibly toggle between the fluffy and smooth colony-forming states. Using a combination of flow cytometry and high-throughput restriction-site associated DNA tag sequencing, we show that this switch is correlated with a change in chromosomal copy number. Furthermore, the gain of a single chromosome is sufficient to switch a strain from the fluffy to the smooth state, and its subsequent loss to revert the strain back to the fluffy state. Because copy number imbalance of six of the 16 S. cerevisiae chromosomes and even a single gene can modulate the switch, our results support the hypothesis that the state switch is produced by dosage-sensitive genes, rather than a general response to altered DNA content. These findings add a complex, multicellular phenotype to the list of molecular and cellular traits known to be altered by aneuploidy and suggest that chromosome missegregation can provide a quick, heritable, and reversible mechanism by which organisms can toggle between phenotypes. PMID:23812752

  2. Finding self-directed learning readiness and fostering self-directed learning through weekly assessment of self-directed learning topics during undergraduate clinical training in ophthalmology

    PubMed Central

    Sahoo, Soumendra

    2016-01-01

    Background: To know the individual’s current level of readiness and to manage self-directed learning (SDL) not only help learners but also the instructors. The objectives of this study were to find SDL readiness among 4th year medical student and to analyze the effect of weekly assessment of SDL topics. Methodology: This was a cross-sectional study to analyze the effect of weekly assessment of SDL topics in fostering SDL. The 51 4th year students during a clinical posting in ophthalmology participated for this study. Each recruited student was tested for SDL readiness through the SDL readiness scale (SDLRS) developed by Lucy Guglielmino (1978), which was validated in our local setting and responses were collected from students on the 1st day of the clinical posting. The students chose SDL topics which were assessed on a weekly basis in the form of scenario-based multiple choice questionnaires. Written feedback was collected from each student regarding such activity during their clinical posting, especially to know the actual utilization of SDL hours provided in teaching schedule, satisfaction on the type of questions and motivation for SDL. Results: The mean SDLRS score in male students were 214.15 ± 19.73 and in female 207.95 ± 17.983, which falls under average score as defined in Guglielmino scale. The majority of study population expressed better utilization of SDL study hours because of weekly assessment than when they had no assessment for SDL. Conclusions: Majority of the study population were found to be ready for SDL. The weekly assessment of SDL topics was found to stimulate proper utilization of SDL slots in teaching schedule thereby fostering SDL habits. PMID:27563580

  3. Deciphering unusual uncultured magnetotactic multicellular prokaryotes through genomics

    PubMed Central

    Abreu, Fernanda; Morillo, Viviana; Nascimento, Fabrícia F; Werneck, Clarissa; Cantão, Mauricio Egidio; Ciapina, Luciane Prioli; de Almeida, Luiz Gonzaga Paula; Lefèvre, Christopher T; Bazylinski, Dennis A; de Vasconcelos, Ana Tereza Ribeiro; Lins, Ulysses

    2014-01-01

    Candidatus Magnetoglobus multicellularis (Ca. M. multicellularis) is a member of a group of uncultured magnetotactic prokaryotes that possesses a unique multicellular morphology. To better understand this organism's physiology, we used a genomic approach through pyrosequencing. Genomic data analysis corroborates previous structural studies and reveals the proteins that are likely involved in multicellular morphogenesis of this microorganism. Interestingly, some detected protein sequences that might be involved in cell adhesion are homologues to phylogenetically unrelated filamentous multicellular bacteria proteins, suggesting their contribution in the early development of multicellular organization in Bacteria. Genes related to the behavior of Ca. M. multicellularis (chemo-, photo- and magnetotaxis) and its metabolic capabilities were analyzed. On the basis of the genomic–physiologic information, enrichment media were tested. One medium supported chemoorganoheterotrophic growth of Ca. M. multicellularis and allowed the microorganisms to maintain their multicellular morphology and cell cycle, confirming for the first time that the entire life cycle of the MMP occurs in a multicellular form. Because Ca. M. multicellularis has a unique multicellular life style, its cultivation is an important achievement for further studies regarding the multicellular evolution in prokaryotes. PMID:24196322

  4. Carcinoma-associated fibroblasts: orchestrating the composition of malignancy.

    PubMed

    Gascard, Philippe; Tlsty, Thea D

    2016-05-01

    The tumor stroma is no longer seen solely as physical support for mutated epithelial cells but as an important modulator and even a driver of tumorigenicity. Within the tumor stromal milieu, heterogeneous populations of fibroblast-like cells, collectively termed carcinoma-associated fibroblasts (CAFs), are key players in the multicellular, stromal-dependent alterations that contribute to malignant initiation and progression. This review focuses on novel insights into the contributions of CAFs to disease progression, emergent events leading to the generation of CAFs, identification of CAF-specific biomarkers predictive of disease outcome, and recent therapeutic approaches aimed at blunting or reverting detrimental protumorigenic phenotypes associated with CAFs. PMID:27151975

  5. Multicellular density fluctuations in epithelial monolayers

    NASA Astrophysics Data System (ADS)

    Zehnder, Steven M.; Wiatt, Marina K.; Uruena, Juan M.; Dunn, Alison C.; Sawyer, W. Gregory; Angelini, Thomas E.

    2015-09-01

    Changes in cell size often accompany multicellular motion in tissue, and cell number density is known to strongly influence collective migration in monolayers. Density fluctuations in other forms of active matter have been explored extensively, but not the potential role of density fluctuations in collective cell migration. Here we investigate collective motion in cell monolayers, focusing on the divergent component of the migration velocity field to probe density fluctuations. We find spatial patterns of diverging and converging cell groups throughout the monolayers, which oscillate in time with a period of approximately 3-4 h. Simultaneous fluorescence measurements of a cytosol dye within the cells show that fluid passes between groups of cells, facilitating these oscillations in cell density. Our findings reveal that cell-cell interactions in monolayers may be mediated by intercellular fluid flow.

  6. Geometry Shapes Evolution of Early Multicellularity

    PubMed Central

    Libby, Eric; Ratcliff, William; Travisano, Michael; Kerr, Ben

    2014-01-01

    Organisms have increased in complexity through a series of major evolutionary transitions, in which formerly autonomous entities become parts of a novel higher-level entity. One intriguing feature of the higher-level entity after some major transitions is a division of reproductive labor among its lower-level units in which reproduction is the sole responsibility of a subset of units. Although it can have clear benefits once established, it is unknown how such reproductive division of labor originates. We consider a recent evolution experiment on the yeast Saccharomyces cerevisiae as a unique platform to address the issue of reproductive differentiation during an evolutionary transition in individuality. In the experiment, independent yeast lineages evolved a multicellular “snowflake-like” cluster formed in response to gravity selection. Shortly after the evolution of clusters, the yeast evolved higher rates of cell death. While cell death enables clusters to split apart and form new groups, it also reduces their performance in the face of gravity selection. To understand the selective value of increased cell death, we create a mathematical model of the cellular arrangement within snowflake yeast clusters. The model reveals that the mechanism of cell death and the geometry of the snowflake interact in complex, evolutionarily important ways. We find that the organization of snowflake yeast imposes powerful limitations on the available space for new cell growth. By dying more frequently, cells in clusters avoid encountering space limitations, and, paradoxically, reach higher numbers. In addition, selection for particular group sizes can explain the increased rate of apoptosis both in terms of total cell number and total numbers of collectives. Thus, by considering the geometry of a primitive multicellular organism we can gain insight into the initial emergence of reproductive division of labor during an evolutionary transition in individuality. PMID:25233196

  7. Multicellular computing using conjugation for wiring.

    PubMed

    Goñi-Moreno, Angel; Amos, Martyn; de la Cruz, Fernando

    2013-01-01

    Recent efforts in synthetic biology have focussed on the implementation of logical functions within living cells. One aim is to facilitate both internal "re-programming" and external control of cells, with potential applications in a wide range of domains. However, fundamental limitations on the degree to which single cells may be re-engineered have led to a growth of interest in multicellular systems, in which a "computation" is distributed over a number of different cell types, in a manner analogous to modern computer networks. Within this model, individual cell type perform specific sub-tasks, the results of which are then communicated to other cell types for further processing. The manner in which outputs are communicated is therefore of great significance to the overall success of such a scheme. Previous experiments in distributed cellular computation have used global communication schemes, such as quorum sensing (QS), to implement the "wiring" between cell types. While useful, this method lacks specificity, and limits the amount of information that may be transferred at any one time. We propose an alternative scheme, based on specific cell-cell conjugation. This mechanism allows for the direct transfer of genetic information between bacteria, via circular DNA strands known as plasmids. We design a multi-cellular population that is able to compute, in a distributed fashion, a Boolean XOR function. Through this, we describe a general scheme for distributed logic that works by mixing different strains in a single population; this constitutes an important advantage of our novel approach. Importantly, the amount of genetic information exchanged through conjugation is significantly higher than the amount possible through QS-based communication. We provide full computational modelling and simulation results, using deterministic, stochastic and spatially-explicit methods. These simulations explore the behaviour of one possible conjugation-wired cellular computing

  8. Role of Multicellular Aggregates in Biofilm Formation

    PubMed Central

    Kragh, Kasper N.; Hutchison, Jaime B.; Melaugh, Gavin; Rodesney, Chris; Roberts, Aled E. L.; Irie, Yasuhiko; Jensen, Peter Ø.; Diggle, Stephen P.; Allen, Rosalind J.

    2016-01-01

    ABSTRACT In traditional models of in vitro biofilm development, individual bacterial cells seed a surface, multiply, and mature into multicellular, three-dimensional structures. Much research has been devoted to elucidating the mechanisms governing the initial attachment of single cells to surfaces. However, in natural environments and during infection, bacterial cells tend to clump as multicellular aggregates, and biofilms can also slough off aggregates as a part of the dispersal process. This makes it likely that biofilms are often seeded by aggregates and single cells, yet how these aggregates impact biofilm initiation and development is not known. Here we use a combination of experimental and computational approaches to determine the relative fitness of single cells and preformed aggregates during early development of Pseudomonas aeruginosa biofilms. We find that the relative fitness of aggregates depends markedly on the density of surrounding single cells, i.e., the level of competition for growth resources. When competition between aggregates and single cells is low, an aggregate has a growth disadvantage because the aggregate interior has poor access to growth resources. However, if competition is high, aggregates exhibit higher fitness, because extending vertically above the surface gives cells at the top of aggregates better access to growth resources. Other advantages of seeding by aggregates, such as earlier switching to a biofilm-like phenotype and enhanced resilience toward antibiotics and immune response, may add to this ecological benefit. Our findings suggest that current models of biofilm formation should be reconsidered to incorporate the role of aggregates in biofilm initiation. PMID:27006463

  9. Multicellular Computing Using Conjugation for Wiring

    PubMed Central

    Goñi-Moreno, Angel; Amos, Martyn; de la Cruz, Fernando

    2013-01-01

    Recent efforts in synthetic biology have focussed on the implementation of logical functions within living cells. One aim is to facilitate both internal “re-programming” and external control of cells, with potential applications in a wide range of domains. However, fundamental limitations on the degree to which single cells may be re-engineered have led to a growth of interest in multicellular systems, in which a “computation” is distributed over a number of different cell types, in a manner analogous to modern computer networks. Within this model, individual cell type perform specific sub-tasks, the results of which are then communicated to other cell types for further processing. The manner in which outputs are communicated is therefore of great significance to the overall success of such a scheme. Previous experiments in distributed cellular computation have used global communication schemes, such as quorum sensing (QS), to implement the “wiring” between cell types. While useful, this method lacks specificity, and limits the amount of information that may be transferred at any one time. We propose an alternative scheme, based on specific cell-cell conjugation. This mechanism allows for the direct transfer of genetic information between bacteria, via circular DNA strands known as plasmids. We design a multi-cellular population that is able to compute, in a distributed fashion, a Boolean XOR function. Through this, we describe a general scheme for distributed logic that works by mixing different strains in a single population; this constitutes an important advantage of our novel approach. Importantly, the amount of genetic information exchanged through conjugation is significantly higher than the amount possible through QS-based communication. We provide full computational modelling and simulation results, using deterministic, stochastic and spatially-explicit methods. These simulations explore the behaviour of one possible conjugation-wired cellular

  10. Agent Based Modelling Helps in Understanding the Rules by Which Fibroblasts Support Keratinocyte Colony Formation

    PubMed Central

    Sun, Tao; McMinn, Phil; Holcombe, Mike; Smallwood, Rod; MacNeil, Sheila

    2008-01-01

    Background Autologous keratincoytes are routinely expanded using irradiated mouse fibroblasts and bovine serum for clinical use. With growing concerns about the safety of these xenobiotic materials, it is desirable to culture keratinocytes in media without animal derived products. An improved understanding of epithelial/mesenchymal interactions could assist in this. Methodology/Principal Findings A keratincyte/fibroblast o-culture model was developed by extending an agent-based keratinocyte colony formation model to include the response of keratinocytes to both fibroblasts and serum. The model was validated by comparison of the in virtuo and in vitro multicellular behaviour of keratinocytes and fibroblasts in single and co-culture in Greens medium. To test the robustness of the model, several properties of the fibroblasts were changed to investigate their influence on the multicellular morphogenesis of keratinocyes and fibroblasts. The model was then used to generate hypotheses to explore the interactions of both proliferative and growth arrested fibroblasts with keratinocytes. The key predictions arising from the model which were confirmed by in vitro experiments were that 1) the ratio of fibroblasts to keratinocytes would critically influence keratinocyte colony expansion, 2) this ratio needed to be optimum at the beginning of the co-culture, 3) proliferative fibroblasts would be more effective than irradiated cells in expanding keratinocytes and 4) in the presence of an adequate number of fibroblasts, keratinocyte expansion would be independent of serum. Conclusions A closely associated computational and biological approach is a powerful tool for understanding complex biological systems such as the interactions between keratinocytes and fibroblasts. The key outcome of this study is the finding that the early addition of a critical ratio of proliferative fibroblasts can give rapid keratinocyte expansion without the use of irradiated mouse fibroblasts and bovine

  11. Self-directed attention, awareness of bodily states, and suggestibility.

    PubMed

    Scheier, M F; Carver, C S; Gibbons, F X

    1979-09-01

    Two studies tested the hypothesis that self-directed attention would cause increased awareness of internal states and would thus reduce suggestibility effects. Experiment 1 applied this reasoning to the experience of an emotion. Males viewed moderately arousing slides of female nudes after being led to expect the slides to be either highly arousing or nonarousing. As predicted, ratings of the slides corresponded less with these experimentally-manipulated anticipations when self-focus was heightened by the presence of a mirror than when it was not. Experiment 2 examined a different internal experience: the perception of taste. Some subjects were led to expect a strong flavor as part of a test series, and other subjects were led to expect a weak flavor. Subjects high in private self-consciousness were less affected by this expectancy manipulation and more accurate in reporting their actual internal state than were subjects low in private self-consciousness. Discussion centers on the theoretical implications of the findings. PMID:501522

  12. Promotion of Self-directed Learning Using Virtual Patient Cases

    PubMed Central

    Schonder, Kristine; McGee, James

    2013-01-01

    Objective. To assess the effectiveness of virtual patient cases to promote self-directed learning (SDL) in a required advanced therapeutics course. Design. Virtual patient software based on a branched-narrative decision-making model was used to create complex patient case simulations to replace lecture-based instruction. Within each simulation, students used SDL principles to learn course objectives, apply their knowledge through clinical recommendations, and assess their progress through patient outcomes and faculty feedback linked to their individual decisions. Group discussions followed each virtual patient case to provide further interpretation, clarification, and clinical perspective. Assessments. Students found the simulated patient cases to be organized (90%), enjoyable (82%), intellectually challenging (97%), and valuable to their understanding of course content (91%). Students further indicated that completion of the virtual patient cases prior to class permitted better use of class time (78%) and promoted SDL (84%). When assessment questions regarding material on postoperative nausea and vomiting were compared, no difference in scores were found between the students who attended the lecture on the material in 2011 (control group) and those who completed the virtual patient case on the material in 2012 (intervention group). Conclusion. Completion of virtual patient cases, designed to replace lectures and promote SDL, was overwhelmingly supported by students and proved to be as effective as traditional teaching methods. PMID:24052654

  13. Multicellular architecture of malignant breast epithelia influences mechanics.

    PubMed

    Venugopalan, Gautham; Camarillo, David B; Webster, Kevin D; Reber, Clay D; Sethian, James A; Weaver, Valerie M; Fletcher, Daniel A; El-Samad, Hana; Rycroft, Chris H

    2014-01-01

    Cell-matrix and cell-cell mechanosensing are important in many cellular processes, particularly for epithelial cells. A crucial question, which remains unexplored, is how the mechanical microenvironment is altered as a result of changes to multicellular tissue structure during cancer progression. In this study, we investigated the influence of the multicellular tissue architecture on mechanical properties of the epithelial component of the mammary acinus. Using creep compression tests on multicellular breast epithelial structures, we found that pre-malignant acini with no lumen (MCF10AT) were significantly stiffer than normal hollow acini (MCF10A) by 60%. This difference depended on structural changes in the pre-malignant acini, as neither single cells nor normal multicellular acini tested before lumen formation exhibited these differences. To understand these differences, we simulated the deformation of the acini with different multicellular architectures and calculated their mechanical properties; our results suggest that lumen filling alone can explain the experimentally observed stiffness increase. We also simulated a single contracting cell in different multicellular architectures and found that lumen filling led to a 20% increase in the "perceived stiffness" of a single contracting cell independent of any changes to matrix mechanics. Our results suggest that lumen filling in carcinogenesis alters the mechanical microenvironment in multicellular epithelial structures, a phenotype that may cause downstream disruptions to mechanosensing. PMID:25111489

  14. Multicellular Architecture of Malignant Breast Epithelia Influences Mechanics

    PubMed Central

    Webster, Kevin D.; Reber, Clay D.; Sethian, James A.; Weaver, Valerie M.; Fletcher, Daniel A.; El-Samad, Hana; Rycroft, Chris H.

    2014-01-01

    Cell–matrix and cell–cell mechanosensing are important in many cellular processes, particularly for epithelial cells. A crucial question, which remains unexplored, is how the mechanical microenvironment is altered as a result of changes to multicellular tissue structure during cancer progression. In this study, we investigated the influence of the multicellular tissue architecture on mechanical properties of the epithelial component of the mammary acinus. Using creep compression tests on multicellular breast epithelial structures, we found that pre-malignant acini with no lumen (MCF10AT) were significantly stiffer than normal hollow acini (MCF10A) by 60%. This difference depended on structural changes in the pre-malignant acini, as neither single cells nor normal multicellular acini tested before lumen formation exhibited these differences. To understand these differences, we simulated the deformation of the acini with different multicellular architectures and calculated their mechanical properties; our results suggest that lumen filling alone can explain the experimentally observed stiffness increase. We also simulated a single contracting cell in different multicellular architectures and found that lumen filling led to a 20% increase in the “perceived stiffness” of a single contracting cell independent of any changes to matrix mechanics. Our results suggest that lumen filling in carcinogenesis alters the mechanical microenvironment in multicellular epithelial structures, a phenotype that may cause downstream disruptions to mechanosensing. PMID:25111489

  15. Ferritin nanocontainers that self-direct in synthetic polymer systems

    NASA Astrophysics Data System (ADS)

    Sengonul, Merih C.

    Currently, there are many approaches to introduce functionality into synthetic polymers. Among these, for example, are copolymerization, grafting, and blending methods. However, modifications made by such methods also change the thermodynamics and rheological properties of the polymer system of interest, and each new modification often requires a costly reoptimization of polymer processing. Such a reoptimalization would not be necessary if new functionality could be introduced via a container whose external surface is chemically and physically tuned to interact with the parent polymer. The contents of the container could then be changed without changing other important properties of the parent polymer. In this context this thesis project explores an innovative nanocontainer platform which can be introduced into phase-separating homopolymer blends. Ferritin is a naturally existing nanocontainer that can be used synthetically to package and selectively transport functional moieties to a particular phase that is either in the bulk or on the surface of a homopolymer blend system. The principal focus of this work centers on modifying the surface of wild ferritin to: (1) render modified ferritin soluble in a non-aqueous solvent; and (2) impart it with self-directing properties when exposed to a homopolymer blend surface or incorporated into the bulk of a homopolymer blend. Wild ferritin is water soluble, and this research project successfully modified wild ferritin by grafting either amine-functional poly(ethylene glycol) (PEG) or short-chain alkanes to carbodiimide activated carboxylate groups on ferritin's surface. Such modified ferritin is soluble in dichloromethane (DCM). Modification was confirmed by ion-exchange chromatography, zeta-potential measurements, and electrospray mass spectroscopy. FT-IR was used to quantify the extent of PEGylation of the reaction products through area ratios of the -C-O-C asymmetric stretching vibration of the grafted PEG chains to the

  16. Emotional Intelligence and Self-Directed Learning Readiness among College Students Participating in a Leadership Development Program

    ERIC Educational Resources Information Center

    Radnitzer, Karl David

    2010-01-01

    The purpose of this study was to investigate possible relationships between self-directed learning readiness and emotional intelligence in a leadership development program and if self-directed learning leads to greater self-directed learning capabilities. Prior research has examined self-directed learning and emotional intelligence but never have…

  17. Apprehending multicellularity: regulatory networks, genomics and evolution

    PubMed Central

    Aravind, L.; Anantharaman, Vivek; Venancio, Thiago M.

    2009-01-01

    The genomic revolution has provided the first glimpses of the architecture of regulatory networks. Combined with evolutionary information, the “network view” of life processes leads to remarkable insights into how biological systems have been shaped by various forces. This understanding is critical because biological systems, including regulatory networks, are not products of engineering but of historical contingencies. In this light, we attempt a synthetic overview of the natural history of regulatory networks operating in the development and differentiation of multicellular organisms. We first introduce regulatory networks and their organizational principles as can be deduced using ideas from the graph theory. We then discuss findings from comparative genomics to illustrate the effects of lineage-specific expansions, gene-loss, and non-protein-coding DNA on the architecture of networks. We consider the interaction between expansions of transcription factors, and cis regulatory and more general chromatin state stabilizing elements in the emergence of morphological complexity. Finally, we consider a case study of the Notch sub-network, which is present throughout Metazoa, to examine how such a regulatory system has been pieced together in evolution from new innovations and pre-existing components that were originally functionally distinct. PMID:19530132

  18. Infection and cancer in multicellular organisms.

    PubMed

    Ewald, Paul W; Swain Ewald, Holly A

    2015-07-19

    Evolutionary considerations suggest that oncogenic infections should be pervasive among animal species. Infection-associated cancers are well documented in humans and domestic animals, less commonly reported in undomesticated captive animals, and rarely documented in nature. In this paper, we review the literature associating infectious agents with cancer to evaluate the reasons for this pattern. Non-malignant infectious neoplasms occur pervasively in multicellular life, but oncogenic progression to malignancy is often uncertain. Evidence from humans and domestic animals shows that non-malignant infectious neoplasms can develop into cancer, although generally with low frequency. Malignant neoplasms could be difficult to find in nature because of a low frequency of oncogenic transformation, short survival after malignancy and reduced survival prior to malignancy. Moreover, the evaluation of malignancy can be ambiguous in nature, because criteria for malignancy may be difficult to apply consistently across species. The information available in the literature therefore does not allow for a definitive assessment of the pervasiveness of infectious cancers in nature, but the presence of infectious neoplasias and knowledge about the progression of benign neoplasias to cancer is consistent with a widespread but largely undetected occurrence. PMID:26056368

  19. Infection and cancer in multicellular organisms

    PubMed Central

    Ewald, Paul W.; Swain Ewald, Holly A.

    2015-01-01

    Evolutionary considerations suggest that oncogenic infections should be pervasive among animal species. Infection-associated cancers are well documented in humans and domestic animals, less commonly reported in undomesticated captive animals, and rarely documented in nature. In this paper, we review the literature associating infectious agents with cancer to evaluate the reasons for this pattern. Non-malignant infectious neoplasms occur pervasively in multicellular life, but oncogenic progression to malignancy is often uncertain. Evidence from humans and domestic animals shows that non-malignant infectious neoplasms can develop into cancer, although generally with low frequency. Malignant neoplasms could be difficult to find in nature because of a low frequency of oncogenic transformation, short survival after malignancy and reduced survival prior to malignancy. Moreover, the evaluation of malignancy can be ambiguous in nature, because criteria for malignancy may be difficult to apply consistently across species. The information available in the literature therefore does not allow for a definitive assessment of the pervasiveness of infectious cancers in nature, but the presence of infectious neoplasias and knowledge about the progression of benign neoplasias to cancer is consistent with a widespread but largely undetected occurrence. PMID:26056368

  20. Multicellular oxidant defense in unicellular organisms.

    PubMed Central

    Ma, M; Eaton, J W

    1992-01-01

    Although catalase is thought to be a major defense against hydrogen peroxide (H2O2), the catalase activity within individual Escherichia coli fails to protect against exogenous H2O2. Contrary to earlier reports, we find that dilute suspensions of wild-type and catalase-deficient E. coli are identical in their sensitivity to H2O2, perhaps because even wild-type, catalase-positive E. coli cannot maintain an internal/external concentration gradient of this highly diffusible oxidant. However, concentrated suspensions or colonies of catalase-positive E. coli do preferentially survive H2O2 challenge and can even cross-protect adjacent catalase-deficient organisms. Furthermore, high-density catalase-positive--but not catalase-negative--E. coli can survive and multiply in the presence of competitive, peroxide-generating streptococci. These observations support the concept that bacterial catalase may defend colonial, but not individual, E. coli against environmental H2O2. Group protection by the activity of enzymes that mitigate oxidative stress may have been a driving force in the evolution of multicellular organisms. Images PMID:1518815

  1. Semiautomatic growth analysis of multicellular tumor spheroids.

    PubMed

    Rodday, Bjoern; Hirschhaeuser, Franziska; Walenta, Stefan; Mueller-Klieser, Wolfgang

    2011-10-01

    Multicellular tumor spheroids (MCTS) are routinely employed as three-dimensional in vitro models to study tumor biology. Cultivation of MCTS in spinner flasks provides better growing conditions, especially with regard to the availability of nutrients and oxygen, when compared with microtiter plates. The main endpoint of drug response experiments is spheroid size. It is common practice to analyze spheroid size manually with a microscope and an ocular micrometer. This requires removal of some spheroids from the flask, which entails major limitations such as loss of MCTS and the risk of contamination. With this new approach, the authors present an efficient and highly reproducible method to analyze the size of complete MCTS populations in culture containers with transparent, flat bottoms. MCTS sediments are digitally scanned and spheroid volumes are calculated by computerized image analysis. The equipment includes regular office hardware (personal computer, flatbed scanner) and software (Adobe Photoshop, Microsoft Excel, ImageJ). The accuracy and precision of the method were tested using industrial precision steel beads with known diameter. In summary, in comparison with other methods, this approach provides benefits in terms of semiautomation, noninvasiveness, and low costs. PMID:21908797

  2. Apprehending multicellularity: regulatory networks, genomics, and evolution.

    PubMed

    Aravind, L; Anantharaman, Vivek; Venancio, Thiago M

    2009-06-01

    The genomic revolution has provided the first glimpses of the architecture of regulatory networks. Combined with evolutionary information, the "network view" of life processes leads to remarkable insights into how biological systems have been shaped by various forces. This understanding is critical because biological systems, including regulatory networks, are not products of engineering but of historical contingencies. In this light, we attempt a synthetic overview of the natural history of regulatory networks operating in the development and differentiation of multicellular organisms. We first introduce regulatory networks and their organizational principles as can be deduced using ideas from the graph theory. We then discuss findings from comparative genomics to illustrate the effects of lineage-specific expansions, gene-loss, and nonprotein-coding DNA on the architecture of networks. We consider the interaction between expansions of transcription factors, and cis regulatory and more general chromatin state stabilizing elements in the emergence of morphological complexity. Finally, we consider a case study of the Notch subnetwork, which is present throughout Metazoa, to examine how such a regulatory system has been pieced together in evolution from new innovations and pre-existing components that were originally functionally distinct. PMID:19530132

  3. Mechanical Trade-offs in Experimentally Evolved Multicellular Yeast

    NASA Astrophysics Data System (ADS)

    Jacobeen, Shane; Pentz, Jennifer; Ratcliff, William; Yunker, Peter

    The evolution of multicellularity as much about physics as it is about biology, as selection acts on the physical properties of multicellular bodies. Nascent multicellular organisms are confronted by internal and external forces that act on large length scales and are capable of fracturing intercellular bonds. We study the evolution of the mechanical properties of multicellular `snowflake' yeast that were selected for increased size over ~1,500 generations. While these snowflakes evolve to be larger by mitigating internal forces, they also become more susceptible to fracturing when faced with external compressive forces. Using confocal microscopy and direct mechanical measurements, we investigate the physical underpinnings and consequences of this strength-toughness trade-off.

  4. Aggregative multicellularity evolved independently in the eukaryotic supergroup Rhizaria.

    PubMed

    Brown, Matthew W; Kolisko, Martin; Silberman, Jeffrey D; Roger, Andrew J

    2012-06-19

    Multicellular forms of life have evolved many times, independently giving rise to a diversity of organisms such as animals, plants, and fungi that together comprise the visible biosphere. Yet multicellular life is far more widespread among eukaryotes than just these three lineages. A particularly common form of multicellularity is a social aggregative fruiting lifestyle whereby individual cells associate to form a "fungus-like" sorocarp. This complex developmental process that requires the interaction of thousands of cells working in concert was made famous by the "cellular slime mold"Dictyostelium discoideum, which became an important model organism. Although sorocarpic protistan lineages have been identified in five of the major eukaryote groups, the ubiquitous and globally distributed species Guttulinopsis vulgaris has eluded proper classification. Here we demonstrate, by phylogenomic analyses of a 159-protein data set, that G. vulgaris is a member of Rhizaria and is thus the first member of this eukaryote supergroup known to be capable of aggregative multicellularity. PMID:22608512

  5. 42 CFR 441.550 - Service plan requirements for self-directed model with service budget.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS SERVICES: REQUIREMENTS AND... Plan Option (Community First Choice) § 441.550 Service plan requirements for self-directed model with... attendant care providers to provide self-directed Community First Choice services and supports,...

  6. 42 CFR 441.550 - Service plan requirements for self-directed model with service budget.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS SERVICES: REQUIREMENTS AND... Plan Option (Community First Choice) § 441.550 Service plan requirements for self-directed model with... attendant care providers to provide self-directed Community First Choice services and supports,...

  7. Exploring First-Year Undergraduate Medical Students' Self-Directed Learning Readiness to Physiology

    ERIC Educational Resources Information Center

    Abraham, Reem Rachel; Fisher, Murray; Kamath, Asha; Izzati, T. Aizan; Nabila, Saidatul; Atikah, Nik Nur

    2011-01-01

    Medical students are expected to possess self-directed learning skills to pursue lifelong learning. Previous studies have reported that the readiness for self-directed learning depends on personal attributes as well as the curriculum followed in institutions. Melaka Manipal Medical College of Manipal University (Karnataka, India) offers a Bachelor…

  8. Founders' Continuing Roles in Schools Supporting Self-Directed Learning

    ERIC Educational Resources Information Center

    Nash, Carol

    2014-01-01

    What should be the continuing role of founders in schools supporting self-directed learning? To answer this, the founders' views of two North American schools for self-directed learners will be compared. One school is exam-focused and private; the other is, test-free and public. The founders of both schools have comparable beliefs regarding…

  9. The Readiness of Adults with Attention Deficit Hyperactivity Disorder for Self-Directed Learning

    ERIC Educational Resources Information Center

    Wright, Melissa Sue

    2011-01-01

    This study investigated the readiness for self-directed learning of adults with Attention Deficit Hyperactivity Disorder (ADHD), as well as their overall educational experiences. Using Guglielmino's Self-Directed Learning Readiness Scale for Adults (SDLRS-A), the researcher investigated whether the following factors were significantly related to…

  10. The Effects of a Self-Directed Drug Abuse Education Program on Attitudes of College Students.

    ERIC Educational Resources Information Center

    Blackwell, James Toy, Jr.

    The major purpose of this study was to determine if significant differences in attitude change toward eight drug abuse concepts would be generated among college students when taught a drug abuse education program with the use of self-directed multi-media learning activities. The subjects' opinions and evaluation of the self-directed education…

  11. Conditions Enhancing Self-Directed Learning in the Workplace. A Report to the Participants.

    ERIC Educational Resources Information Center

    1992

    The appreciative inquiry process was used to identify conditions enhancing self-directed learning. Participants in the project did the following: (1) used the five-step process to identify factors/conditions/forces that seemed to cause self-directed learning to occur; (2) created a matrix by combining the factors/conditions/forces with six…

  12. Using Technology to Provide Self-Directed Learning Options for Power Utility Employees.

    ERIC Educational Resources Information Center

    Phelan, Thomas D.

    1994-01-01

    Niagara Mohawk Power Corporation facilitates self-directed learning for career development by providing career advisement via electronic mail and maintaining a database of job descriptions, college programs, and information about other learning providers. Using personal computers helps employees become more self-directed in their careers and…

  13. Self Directed Support and People with Learning Disabilities: A Review of the Published Research Evidence

    ERIC Educational Resources Information Center

    Harkes, Mary Anne; Brown, Michael; Horsburgh, Dorothy

    2014-01-01

    A systematic literature review was undertaken to determine the evidence base underpinning the strategy of Self Directed Support and whether evidence demonstrates that this policy is accessible to everyone with a learning disability. It also sought to identify whether there were any barriers to Self Directed Support for people with severe or…

  14. Self-Directed Teams in the Introductory Information Systems Course: Lessons Learned.

    ERIC Educational Resources Information Center

    Buffington, James R.

    Research clearly supports the efficacy of self-directed teams in the learning of information systems (IS) skills. This paper proposes that the use of self-directed teams demands a considerable amount of direction on the part of the instructor. Students in two sections of an introductory IS class were surveyed with explicit questions about their…

  15. The Relationship between Transformational Leadership and Knowledge Workers' Self-Directed Learning Readiness

    ERIC Educational Resources Information Center

    Aparicio, Ricardo Antonio

    2013-01-01

    The rapid pace of change for knowledge workers competing globally necessitates ongoing continuous learning. Increasingly, knowledge workers will need to be ready--willing and able--to engage in self-directed learning. This makes it important to understand what factors in the work environment might be related to the self-directed learning…

  16. The Effects of Self-Directed Teams in an Automotive Manufacturing Environment

    ERIC Educational Resources Information Center

    Shall, David W.

    2010-01-01

    This study compares self-directed work structures to more traditional supervised work structures in order to determine if the expenditures and efforts required to implement self-directed work teams are warranted. Multiple internal performance metrics are examined in comparing plant work structures in various degrees of implementation between…

  17. Preferences of a Traditional Extension Audience for Self-Directed Delivery Methods.

    ERIC Educational Resources Information Center

    Caldwell, Allen E.; Richardson, John G.

    1995-01-01

    North Carolina farmers growing barley (n=20) tested 3 self-directed information delivery methods: fact sheets, fact sheets plus audiocassettes, and an extension bulletin/pamphlet. The fact sheet/cassette was preferred by 17 of 20; they achieved significant knowledge gains with self-directed methods. The fact sheet/cassette was considered…

  18. Influence of Adult Goal-Setting Instruction on Students' Responsibility toward Self-Directed Competencies

    ERIC Educational Resources Information Center

    Apa Browne, Lynn Geri

    2014-01-01

    Elementary grade students in a mid-Atlantic state school district have not been meeting academic standards on state assessments. Research indicates that academic achievement is connected to self-directed readiness to learn; however, often the instruction in strategies for student self-directed readiness to learn remains teacher-centered. The…

  19. The Inquiry Nature of Primary Schools and Students' Self-Directed Learning Knowledge

    ERIC Educational Resources Information Center

    Van Deur, Penny; Murray-Harvey, Rosalind

    2005-01-01

    Self-directed learning (SDL) is viewed as a desirable outcome of schooling, yet scant information is available to educational leaders and teachers on how to implement an inquiry-based curriculum or to support effectively students' development as self-directed learners. To understand better the relationship between the inquiry nature of primary…

  20. Measuring Self-Directed Learning: A Diagnostic Tool for Adult Learners

    ERIC Educational Resources Information Center

    Khiat, Henry

    2015-01-01

    Self-directed learning is an important form of adult learning (Caffarella, 1993; Knowles, 1975; Knowles, Holton & Swanson, 2005; Merriam, 2001; Merriam & Caffarella, 1999). The strategies of self-directed learning allow adult learners to cope better with their studies while fulfilling family, work and other commitments. This study…

  1. Self-Directed Learning in Gross Human Anatomy: Assessment Outcomes and Student Perceptions

    ERIC Educational Resources Information Center

    Smythe, Gayle; Hughes, Diane

    2008-01-01

    Speech pathology students enrolled in a lecture-based gross human anatomy program completed two out of nine topics in self-directed mode. Student performance in quizzes was compared for the two modes, and the students completed questionnaires on their perceptions of the self-directed mode of delivery. Students performed as well in the first…

  2. Self-Directed Action Affects Planning In Tool-Use Tasks with Toddlers

    PubMed Central

    Claxton, Laura J.; McCarty, Michael E.; Keen, Rachel

    2009-01-01

    Toddlers grasp a tool more effectively when it is self-directed (e.g., spoon) than other-directed (e.g., hammer), possibly because the consequences of self-directed actions are more obvious. When the negative consequences of an inefficient grip were made equally salient, the self- versus other-directed differences remained. PMID:19185350

  3. SELF-DIRECTED LEARNING, TEAMWORK, HOLISTIC VIEW AND ORAL HEALTH.

    PubMed

    Leisnert, Leif

    2014-01-01

    The dental program at the Malmö Dental School, the so called Malmö-model, is guided by four linked principles: self-directed learning, teamwork, a holistic view of patient care, and oral health (Fig.1). Self-assessment ability is a critical competence for healthcare professionals, necessary for the successful adaptation to the modern life-long learning environment. Educational research seems to point out two critical factors for the development of such skills, continuous practice of self-assessment and constructive feedback. The first study presented in this thesis assessed students' self-assessment ability by means of the Interactive Examination in a cohort of senior dental students, who had gone through an identical assessment procedure during their second year of studies. The results indicated that self-assessment ability was not directly relevant to subject knowledge. Upon graduation, there were a number of students (10%) with significant self-assessment difficulties. Early detection of students with weak self-assessment abilities appears possible to achieve. The aim of the second study, concerning teamwork and holistic view, was to investigate if highlighting teamwork between dental and dental hygienist students could improve the students' holistic view on patients, as well as their knowledge of, and insight into, each other's future professions. This project showed that by initiating teamwork between dental and dental hygienist students, it was possible to increase students' knowledge on dental hygienists competence, develop students' perceived holistic view on patients, and prepare students for teamwork. The third study explored findings clinicians used when diagnosing chronic periodontitis. A questionnaire was distributed to students, dental teachers and clinical supervisors in the Public Dental Services. Within all categories of clinicians, the majority of the clinicians used deepened pocket, bone loss on x-rays, and bleeding as findings. There were

  4. Multicellularity in green algae: upsizing in a walled complex.

    PubMed

    Domozych, David S; Domozych, Catherine E

    2014-01-01

    Modern green algae constitute a large and diverse taxonomic assemblage that encompasses many multicellular phenotypes including colonial, filamentous, and parenchymatous forms. In all multicellular green algae, each cell is surrounded by an extracellular matrix (ECM), most often in the form of a cell wall. Volvocalean taxa like Volvox have an elaborate, gel-like, hydroxyproline rich glycoprotein covering that contains the cells of the colony. In "ulvophytes," uronic acid-rich and sulfated polysaccharides are the likely adhesion agents that maintain the multicellular habit. Charophytes also produce polysaccharide-rich cell walls and in late divergent taxa, pectin plays a critical role in cell adhesion in the multicellular complex. Cell walls are products of coordinated interaction of membrane trafficking, cytoskeletal dynamics and the cell's signal transduction machinery responding both to precise internal clocks and external environmental cues. Most often, these activities must be synchronized with the secretion, deposition and remodeling of the polymers of the ECM. Rapid advances in molecular genetics, cell biology and cell wall biochemistry of green algae will soon provide new insights into the evolution and subcellular processes leading to multicellularity. PMID:25477895

  5. Multicellularity in green algae: upsizing in a walled complex

    PubMed Central

    Domozych, David S.; Domozych, Catherine E.

    2014-01-01

    Modern green algae constitute a large and diverse taxonomic assemblage that encompasses many multicellular phenotypes including colonial, filamentous, and parenchymatous forms. In all multicellular green algae, each cell is surrounded by an extracellular matrix (ECM), most often in the form of a cell wall. Volvocalean taxa like Volvox have an elaborate, gel-like, hydroxyproline rich glycoprotein covering that contains the cells of the colony. In “ulvophytes,” uronic acid-rich and sulfated polysaccharides are the likely adhesion agents that maintain the multicellular habit. Charophytes also produce polysaccharide-rich cell walls and in late divergent taxa, pectin plays a critical role in cell adhesion in the multicellular complex. Cell walls are products of coordinated interaction of membrane trafficking, cytoskeletal dynamics and the cell’s signal transduction machinery responding both to precise internal clocks and external environmental cues. Most often, these activities must be synchronized with the secretion, deposition and remodeling of the polymers of the ECM. Rapid advances in molecular genetics, cell biology and cell wall biochemistry of green algae will soon provide new insights into the evolution and subcellular processes leading to multicellularity. PMID:25477895

  6. Triassic origin and early radiation of multicellular volvocine algae

    PubMed Central

    Herron, Matthew D.; Hackett, Jeremiah D.; Aylward, Frank O.; Michod, Richard E.

    2009-01-01

    Evolutionary transitions in individuality (ETIs) underlie the watershed events in the history of life on Earth, including the origins of cells, eukaryotes, plants, animals, and fungi. Each of these events constitutes an increase in the level of complexity, as groups of individuals become individuals in their own right. Among the best-studied ETIs is the origin of multicellularity in the green alga Volvox, a model system for the evolution of multicellularity and cellular differentiation. Since its divergence from unicellular ancestors, Volvox has evolved into a highly integrated multicellular organism with cellular specialization, a complex developmental program, and a high degree of coordination among cells. Remarkably, all of these changes were previously thought to have occurred in the last 50–75 million years. Here we estimate divergence times using a multigene data set with multiple fossil calibrations and use these estimates to infer the times of developmental changes relevant to the evolution of multicellularity. Our results show that Volvox diverged from unicellular ancestors at least 200 million years ago. Two key innovations resulting from an early cycle of cooperation, conflict and conflict mediation led to a rapid integration and radiation of multicellular forms in this group. This is the only ETI for which a detailed timeline has been established, but multilevel selection theory predicts that similar changes must have occurred during other ETIs. PMID:19223580

  7. Effect of an osmotic stress on multicellular aggregates.

    PubMed

    Monnier, Sylvain; Delarue, Morgan; Brunel, Benjamin; Dolega, Monika E; Delon, Antoine; Cappello, Giovanni

    2016-02-01

    There is increasing evidence that multicellular structures respond to mechanical cues, such as the confinement and compression exerted by the surrounding environment. In order to understand the response of tissues to stress, we investigate the effect of an isotropic stress on different biological systems. The stress is generated using the osmotic pressure induced by a biocompatible polymer. We compare the response of multicellular spheroids, individual cells and matrigel to the same osmotic perturbation. Our findings indicate that the osmotic pressure occasioned by polymers acts on these systems like an isotropic mechanical stress. When submitted to this pressure, the volume of multicellular spheroids decreases much more than one could expect from the behavior of individual cells. PMID:26210402

  8. A conceptual framework for the evolutionary origins of multicellularity

    NASA Astrophysics Data System (ADS)

    Libby, Eric; Rainey, Paul B.

    2013-06-01

    The evolution of multicellular organisms from unicellular counterparts involved a transition in Darwinian individuality from single cells to groups. A particular challenge is to understand the nature of the earliest groups, the causes of their evolution, and the opportunities for emergence of Darwinian properties. Here we outline a conceptual framework based on a logical set of possible pathways for evolution of the simplest self-replicating groups. Central to these pathways is the recognition of a finite number of routes by which genetic information can be transmitted between individual cells and groups. We describe the form and organization of each primordial group state and consider factors affecting persistence and evolution of the nascent multicellular forms. Implications arising from our conceptual framework become apparent when attempting to partition fitness effects at individual and group levels. These are discussed with reference to the evolutionary emergence of individuality and its manifestation in extant multicellular life—including those of marginal Darwinian status.

  9. Multiscale modeling of the dynamics of multicellular systems

    NASA Astrophysics Data System (ADS)

    Kosztin, Ioan

    2011-03-01

    Describing the biomechanical properties of cellular systems, regarded as complex highly viscoelastic materials, is a difficult problem of great conceptual and practical value. Here we present a novel approach, referred to as the Cellular Particle Dynamics (CPD) method, for: (i) quantitatively relating biomechanical properties at the cell level to those at the multicellular and tissue level, and (ii) describing and predicting the time evolution of multicellular systems that undergo biomechanical relaxations. In CPD cells are modeled as an ensemble of cellular particles (CPs) that interact via short range contact interactions, characterized by an attractive (adhesive interaction) and a repulsive (excluded volume interaction) component. The time evolution of the spatial conformation of the multicellular system is determined by following the trajectories of all CPs through integration of their equations of motion. Cell and multicellular level biomechanical properties (e.g., viscosity, surface tension and shear modulus) are determined through the combined use of experiments and theory of continuum viscoelastic media. The same biomechanical properties are also ``measured'' computationally by employing the CPD method, the results being expressed in terms of CPD parameters. Once these parameters have been calibrated experimentally, the formalism provides a systematic framework to predict the time evolution of complex multicellular systems during shape-changing biomechanical transformations. By design, the CPD method is rather flexible and most suitable for multiscale modeling of multicellular system. The spatial level of detail of the system can be easily tuned by changing the number of CPs in a cell. Thus, CPD can be used equally well to describe both cell level processes (e.g., the adhesion of two cells) and tissue level processes (e.g., the formation of 3D constructs of millions of cells through bioprinting). Work supported by NSF [FIBR-0526854 and PHY-0957914

  10. Self-Directed Learning: A Must Skill in the Information Age.

    ERIC Educational Resources Information Center

    Zemke, Ron

    1982-01-01

    Discusses the theory of Lucy and Paul Guglielmino that individuals must take more responsibility for the management of their learning. Describes a self-directed learner as one who takes charge, accepts responsibiltiy, and is not stopped by problems. (JOW)

  11. The relationship between assessment methods and self-directed learning readiness in medical education

    PubMed Central

    2016-01-01

    Objectives   This research explored the assessment of self-directed learning readiness within the comprehensive evaluation of medical students’ knowledge and skills and the extent to which several variables predicted participants’ self-directed learning readiness prior to their graduation. Methods   Five metrics for evaluating medical students were considered in a multiple regression analysis.  Fourth-year medical students at a competitive US medical school received an informed consent and an online survey.  Participants voluntarily completed a self-directed learning readiness scale that assessed four subsets of self-directed learning readiness and consented to the release of their academic records. Results   The assortment of metrics considered in this study only vaguely captured students’ self-directedness.  The strongest predictors were faculty evaluations of students’ performance on clerkship rotations.  Specific clerkship grades were mildly predictive of three subscales.  The Pediatrics clerkship modestly predicted critical self-evaluation (r=-.30, p=.01) and the Psychiatry clerkship mildly predicted learning self-efficacy (r =-.30, p=.01), while the Junior Surgery clerkship nominally correlated with participants’ effective organization for learning (r=.21, p=.05).  Other metrics examined did not contribute to predicting participants’ readiness for self-directed learning. Conclusions   Given individual differences among participants for the variables considered, no combination of students’ grades and/or test scores overwhelmingly predicted their aptitude for self-directed learning.  Considering the importance of fostering medical students’ self-directed learning skills, schools need a reliable and pragmatic approach to measure them.  This data analysis, however, offered no clear-cut way of documenting students’ self-directed learning readiness based on the evaluation metrics included. PMID:26970653

  12. On the teaching model of website-based collaborated self-directed study

    NASA Astrophysics Data System (ADS)

    Jing, Zhihua; Zeng, Yingxiong; Wen, Chunyu

    2011-12-01

    Based on the theory of collaborated self-directed study and the strengths of modern education technology, the study explores application of websites for collaborated self-directed college English learning. It introduces the characteristics and functions of the website developed to assist college English teaching in China. It also points out the problems currently existing among teachers and students, and puts forward some suggestions and strategies for the improvement of the application of the website.

  13. The Impact of Advanced Pharmacy Practice Experiences on Students' Readiness for Self-directed Learning

    PubMed Central

    Haines, Stuart T.; Plaza, Cecilia M.; Sturpe, Deborah A.; Williams, Greg; Rodriguez de Bittner, Magaly A.; Roffman, David S.

    2009-01-01

    Objective To evaluate the impact of advanced pharmacy practice experiences (APPEs) on doctor of pharmacy (PharmD) students' readiness for self-directed learning. Methods The Self-Directed Learning Readiness Scale (SDLRS) was administered to students prior to and after completing their APPEs. SDLRS is a validated instrument that determines the relative degree to which students have the attitudes and motivation to engage in self-directed learning. Results Seventy-seven (64%) students completed the SDLRS prior to starting their APPEs and 80 (67%) students completed the instrument after completing their APPEs. Forty-six (38%) students completed both. Prior to starting their APPEs, 74% of students scored greater than 150 on the SDLRS, indicating a high level of readiness for self-directed learning. No significant difference was found between the mean scores of students who took the SDLRS both prior to (159 ± 20) and after completing their APPEs (159 ± 24; p > 0.05). Conclusion Students at our institution appear to be ready for self-directed learning but APPEs had a minimal impact on their readiness for self-directed learning. PMID:19657498

  14. The reverse evolution from multicellularity to unicellularity during carcinogenesis.

    PubMed

    Chen, Han; Lin, Fangqin; Xing, Ke; He, Xionglei

    2015-01-01

    Theoretical reasoning suggests that cancer may result from a knockdown of the genetic constraints that evolved for the maintenance of metazoan multicellularity. By characterizing the whole-life history of a xenograft tumour, here we show that metastasis is driven by positive selection for general loss-of-function mutations on multicellularity-related genes. Expression analyses reveal mainly downregulation of multicellularity-related genes and an evolving expression profile towards that of embryonic stem cells, the cell type resembling unicellular life in its capacity of unlimited clonal proliferation. Also, the emergence of metazoan multicellularity ~600 Myr ago is accompanied by an elevated birth rate of cancer genes, and there are more loss-of-function tumour suppressors than activated oncogenes in a typical tumour. These data collectively suggest that cancer represents a loss-of-function-driven reverse evolution back to the unicellular 'ground state'. This cancer evolution model may account for inter-/intratumoural genetic heterogeneity, could explain distant-organ metastases and hold implications for cancer therapy. PMID:25751731

  15. Regulated aggregative multicellularity in a close unicellular relative of metazoa

    PubMed Central

    Sebé-Pedrós, Arnau; Irimia, Manuel; del Campo, Javier; Parra-Acero, Helena; Russ, Carsten; Nusbaum, Chad; Blencowe, Benjamin J; Ruiz-Trillo, Iñaki

    2013-01-01

    The evolution of metazoans from their unicellular ancestors was one of the most important events in the history of life. However, the cellular and genetic changes that ultimately led to the evolution of multicellularity are not known. In this study, we describe an aggregative multicellular stage in the protist Capsaspora owczarzaki, a close unicellular relative of metazoans. Remarkably, transition to the aggregative stage is associated with significant upregulation of orthologs of genes known to establish multicellularity and tissue architecture in metazoans. We further observe transitions in regulated alternative splicing during the C. owczarzaki life cycle, including the deployment of an exon network associated with signaling, a feature of splicing regulation so far only observed in metazoans. Our results reveal the existence of a highly regulated aggregative stage in C. owczarzaki and further suggest that features of aggregative behavior in an ancestral protist may had been co-opted to develop some multicellular properties currently seen in metazoans. DOI: http://dx.doi.org/10.7554/eLife.01287.001 PMID:24368732

  16. Micro-Mold Design Controls the 3D Morphological Evolution of Self-Assembling Multicellular Microtissues

    PubMed Central

    Svoronos, Alexander A.; Tejavibulya, Nalin; Schell, Jacquelyn Y.; Shenoy, Vivek B.

    2014-01-01

    When seeded into nonadhesive micro-molds, cells self-assemble three-dimensional (3D) multicellular microtissues via the action of cytoskeletal-mediated contraction and cell–cell adhesion. The size and shape of the tissue is a function of the cell type and the size, shape, and obstacles of the micro-mold. In this article, we used human fibroblasts to investigate some of the elements of mold design and how they can be used to guide the morphological changes that occur as a 3D tissue self-organizes. In a loop-ended dogbone mold with two nonadhesive posts, fibroblasts formed a self-constrained tissue whose tension induced morphological changes that ultimately caused the tissue to thin and rupture. Increasing the width of the dogbone's connecting rod increased the stability, whereas increasing its length decreased the stability. Mapping the rupture points showed that the balance of cell volume between the toroid and connecting rod regions of the dogbone tissue controlled the point of rupture. When cells were treated with transforming growth factor-β1, dogbones ruptured sooner due to increased cell contraction. In mold designs to form tissues with more complex shapes such as three interconnected toroids or a honeycomb, obstacle design controlled tension and tissue morphology. When the vertical posts were changed to cones, they became tension modulators that dictated when and where tension was released in a large self-organizing tissue. By understanding how elements of mold design control morphology, we can produce better models to study organogenesis, examine 3D cell mechanics, and fabricate building parts for tissue engineering. PMID:24147855

  17. Micro-mold design controls the 3D morphological evolution of self-assembling multicellular microtissues.

    PubMed

    Svoronos, Alexander A; Tejavibulya, Nalin; Schell, Jacquelyn Y; Shenoy, Vivek B; Morgan, Jeffrey R

    2014-04-01

    When seeded into nonadhesive micro-molds, cells self-assemble three-dimensional (3D) multicellular microtissues via the action of cytoskeletal-mediated contraction and cell-cell adhesion. The size and shape of the tissue is a function of the cell type and the size, shape, and obstacles of the micro-mold. In this article, we used human fibroblasts to investigate some of the elements of mold design and how they can be used to guide the morphological changes that occur as a 3D tissue self-organizes. In a loop-ended dogbone mold with two nonadhesive posts, fibroblasts formed a self-constrained tissue whose tension induced morphological changes that ultimately caused the tissue to thin and rupture. Increasing the width of the dogbone's connecting rod increased the stability, whereas increasing its length decreased the stability. Mapping the rupture points showed that the balance of cell volume between the toroid and connecting rod regions of the dogbone tissue controlled the point of rupture. When cells were treated with transforming growth factor-β1, dogbones ruptured sooner due to increased cell contraction. In mold designs to form tissues with more complex shapes such as three interconnected toroids or a honeycomb, obstacle design controlled tension and tissue morphology. When the vertical posts were changed to cones, they became tension modulators that dictated when and where tension was released in a large self-organizing tissue. By understanding how elements of mold design control morphology, we can produce better models to study organogenesis, examine 3D cell mechanics, and fabricate building parts for tissue engineering. PMID:24147855

  18. Self-directed learning: implications and limitations for undergraduate nursing education.

    PubMed

    Levett-Jones, Tracy L

    2005-07-01

    Self-directed learning (SDL) is an educational concept that has received increasing attention in recent years, particularly in the context of higher education. Whilst the benefits of SDL have been espoused by a number of adult education theorists (Brookfield, S., 1986. Understanding and Facilitating Adult Learning. Jossey-Bass, San Francisco; Houle, C., 1984. Patterns of Learning: New Perspectives on Life-Span Education. Jossey-Bass, San Francisco; Knowles, M., 1998. The Adult Leaner: A Neglected Species, fifth ed., Gulf, Houston; Tough, A., 1979. The Adults Learning Project: A Fresh Approach to Theory and Practice in Adult Learning. Ontario Institute for Studies in Education, Toronto), its introduction into curricula has not always been successful (Nolan, J., Nolan, M., 1997a. Self-directed and student-centred learning in nurse education: 1. British Journal of Nursing 6 (1), 51-55; Nolan, J., Nolan, M., 1997b. Self-directed and student-centred learning in nurse education: 2. British Journal of Nursing 6 (2), 103-107; Slevin, O., Lavery, M., 1991. Self-directed learning and student supervision. Nurse Education Today 11, 368-377). The indiscriminate application of SDL principles and poorly prepared teachers and/or students has at times meant that the introduction of SDL has been resented rather than welcomed (Iwasiw, C., 1987. The role of the teacher in self-directed learning. Nurse Education Today 7, 222-227; Turunen, H., Taskinen, H., Voutilainen, U., Tossavainen, K., Sinkkonen, S., 1997. Nursing and social work students' initial orientation towards their studies. Nurse Education Today 17, 67-71). This paper clarifies and explores these issues by: (a) examining the origins of SDL; (b) discussing the relevance of self-directed learning to Knowles' theory of adult learning and contemporary educational practices such as enquiry based learning and problem based learning; and (c) highlighting the implications and limitations of SDL with regard to adult education in

  19. Detecting Tree-like Multicellular Life on Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Doughty, Christopher E.; Wolf, Adam

    2010-11-01

    Over the next two decades, NASA and ESA are planning a series of space-based observatories to find Earth-like planets and determine whether life exists on these planets. Previous studies have assessed the likelihood of detecting life through signs of biogenic gases in the atmosphere or a red edge. Biogenic gases and the red edge could be signs of either single-celled or multicellular life. In this study, we propose a technique with which to determine whether tree-like multicellular life exists on extrasolar planets. For multicellular photosynthetic organisms on Earth, competition for light and the need to transport water and nutrients has led to a tree-like body plan characterized by hierarchical branching networks. This design results in a distinct bidirectional reflectance distribution function (BRDF) that causes differing reflectance at different sun/view geometries. BRDF arises from the changing visibility of the shadows cast by objects, and the presence of tree-like structures is clearly distinguishable from flat ground with the same reflectance spectrum. We examined whether the BRDF could detect the existence of tree-like structures on an extrasolar planet by using changes in planetary albedo as a planet orbits its star. We used a semi-empirical BRDF model to simulate vegetation reflectance at different planetary phase angles and both simulated and real cloud cover to calculate disk and rotation-averaged planetary albedo for a vegetated and non-vegetated planet with abundant liquid water. We found that even if the entire planetary albedo were rendered to a single pixel, the rate of increase of albedo as a planet approaches full illumination would be comparatively greater on a vegetated planet than on a non-vegetated planet. Depending on how accurately planetary cloud cover can be resolved and the capabilities of the coronagraph to resolve exoplanets, this technique could theoretically detect tree-like multicellular life on exoplanets in 50 stellar systems.

  20. Detecting tree-like multicellular life on extrasolar planets.

    PubMed

    Doughty, Christopher E; Wolf, Adam

    2010-11-01

    Over the next two decades, NASA and ESA are planning a series of space-based observatories to find Earth-like planets and determine whether life exists on these planets. Previous studies have assessed the likelihood of detecting life through signs of biogenic gases in the atmosphere or a red edge. Biogenic gases and the red edge could be signs of either single-celled or multicellular life. In this study, we propose a technique with which to determine whether tree-like multicellular life exists on extrasolar planets. For multicellular photosynthetic organisms on Earth, competition for light and the need to transport water and nutrients has led to a tree-like body plan characterized by hierarchical branching networks. This design results in a distinct bidirectional reflectance distribution function (BRDF) that causes differing reflectance at different sun/view geometries. BRDF arises from the changing visibility of the shadows cast by objects, and the presence of tree-like structures is clearly distinguishable from flat ground with the same reflectance spectrum. We examined whether the BRDF could detect the existence of tree-like structures on an extrasolar planet by using changes in planetary albedo as a planet orbits its star. We used a semi-empirical BRDF model to simulate vegetation reflectance at different planetary phase angles and both simulated and real cloud cover to calculate disk and rotation-averaged planetary albedo for a vegetated and non-vegetated planet with abundant liquid water. We found that even if the entire planetary albedo were rendered to a single pixel, the rate of increase of albedo as a planet approaches full illumination would be comparatively greater on a vegetated planet than on a non-vegetated planet. Depending on how accurately planetary cloud cover can be resolved and the capabilities of the coronagraph to resolve exoplanets, this technique could theoretically detect tree-like multicellular life on exoplanets in 50 stellar systems

  1. Multi-cellular, three-dimensional living mammalian tissue

    NASA Technical Reports Server (NTRS)

    Goodwin, Thomas J. (Inventor); Wolf, David A. (Inventor)

    1994-01-01

    The present invention relates to a multicellular, three-dimensional, living mammalian tissue. The tissue is produced by a co-culture process wherein two distinct types of mammalian cells are co-cultured in a rotating bioreactor which is completely filled with culture media and cell attachment substrates. As the size of the tissue assemblies formed on the attachment substrates changes, the rotation of the bioreactor is adjusted accordingly.

  2. The evolution of cell death programs as prerequisites of multicellularity.

    PubMed

    Huettenbrenner, Simone; Maier, Susanne; Leisser, Christina; Polgar, Doris; Strasser, Stephan; Grusch, Michael; Krupitza, Georg

    2003-06-01

    One of the hallmarks of multicellularity is that the individual cellular fate is sacrificed for the benefit of a higher order of life-the organism. The accidental death of cells in a multicellular organism results in swelling and membrane-rupture and inevitably spills cell contents into the surrounding tissue with deleterious effects for the organism. To avoid this form of necrotic death the cells of metazoans have developed complex self-destruction mechanisms, collectively called programmed cell death, which see to an orderly removal of superfluous cells. Since evolution never invents new genes but plays variations on old themes by DNA mutations, it is not surprising, that some of the genes involved in metazoan death pathways apparently have evolved from homologues in unicellular organisms, where they originally had different functions. Interestingly some unicellular protozoans have developed a primitive form of non-necrotic cell death themselves, which could mean that the idea of an altruistic death for the benefit of genetically identical cells predated the invention of multicellularity. The cell death pathways of protozoans, however, show no homology to those in metazoans, where several death pathways seem to have evolved in parallel. Mitochondria stands at the beginning of several death pathways and also determines, whether a cell has sufficient energy to complete a death program. However, the endosymbiotic bacterial ancestors of mitochondria are unlikely to have contributed to the recent mitochondrial death machinery and therefore, these components may derive from mutated eukaryotic precursors and might have invaded the respective mitochondrial compartments. Although there is no direct evidence, it seems that the prokaryotic-eukaryotic symbiosis created the space necessary for sophisticated death mechanisms on command, which in their distinct forms are major factors for the evolution of multicellular organisms. PMID:12787815

  3. Division of labour and the evolution of multicellularity.

    PubMed

    Ispolatov, Iaroslav; Ackermann, Martin; Doebeli, Michael

    2012-05-01

    Understanding the emergence and evolution of multicellularity and cellular differentiation is a core problem in biology. We develop a quantitative model that shows that a multicellular form emerges from genetically identical unicellular ancestors when the compartmentalization of poorly compatible physiological processes into component cells of an aggregate produces a fitness advantage. This division of labour between the cells in the aggregate occurs spontaneously at the regulatory level owing to mechanisms present in unicellular ancestors and does not require any genetic predisposition for a particular role in the aggregate or any orchestrated cooperative behaviour of aggregate cells. Mathematically, aggregation implies an increase in the dimensionality of phenotype space that generates a fitness landscape with new fitness maxima, in which the unicellular states of optimized metabolism become fitness saddle points. Evolution of multicellularity is modelled as evolution of a hereditary parameter: the propensity of cells to stick together, which determines the fraction of time a cell spends in the aggregate form. Stickiness can increase evolutionarily owing to the fitness advantage generated by the division of labour between cells in an aggregate. PMID:22158952

  4. Emulsion technologies for multicellular tumour spheroid radiation assays.

    PubMed

    McMillan, Kay S; McCluskey, Anthony G; Sorensen, Annette; Boyd, Marie; Zagnoni, Michele

    2016-01-01

    A major limitation with current in vitro technologies for testing anti-cancer therapies at the pre-clinical level is the use of 2D cell culture models which provide a poor reflection of the tumour physiology in vivo. Three dimensional cell culture models, such as the multicellular spheroid, provide instead a more accurate representation. However, existing spheroid-based assessment methods are generally labour-intensive and low-throughput. Emulsion based technologies offer enhanced mechanical stability during multicellular tumour spheroid formation and culture and are scalable to enable higher-throughput assays. The aim of this study was to investigate the characteristics of emulsion-based techniques for the formation and long term culture of multicellular UVW glioma cancer spheroids and apply these findings to assess the cytotoxic effect of radiation on spheroids. Our results showed that spheroids formed within emulsions had similar morphological and growth characteristics to those formed using traditional methods. Furthermore, we have identified the effects produced on the proliferative state of the spheroids due to the compartmentalised nature of the emulsions and applied this for mimicking tumour growth and tumour quiescence. Finally, proof of concept results are shown to demonstrate the scalability potential of the technology for developing high-throughput screening assays. PMID:26456100

  5. Quantitative multivariate analysis of dynamic multicellular morphogenic trajectories.

    PubMed

    White, Douglas E; Sylvester, Jonathan B; Levario, Thomas J; Lu, Hang; Streelman, J Todd; McDevitt, Todd C; Kemp, Melissa L

    2015-07-01

    Interrogating fundamental cell biology principles that govern tissue morphogenesis is critical to better understanding of developmental biology and engineering novel multicellular systems. Recently, functional micro-tissues derived from pluripotent embryonic stem cell (ESC) aggregates have provided novel platforms for experimental investigation; however elucidating the factors directing emergent spatial phenotypic patterns remains a significant challenge. Computational modelling techniques offer a unique complementary approach to probe mechanisms regulating morphogenic processes and provide a wealth of spatio-temporal data, but quantitative analysis of simulations and comparison to experimental data is extremely difficult. Quantitative descriptions of spatial phenomena across multiple systems and scales would enable unprecedented comparisons of computational simulations with experimental systems, thereby leveraging the inherent power of computational methods to interrogate the mechanisms governing emergent properties of multicellular biology. To address these challenges, we developed a portable pattern recognition pipeline consisting of: the conversion of cellular images into networks, extraction of novel features via network analysis, and generation of morphogenic trajectories. This novel methodology enabled the quantitative description of morphogenic pattern trajectories that could be compared across diverse systems: computational modelling of multicellular structures, differentiation of stem cell aggregates, and gastrulation of cichlid fish. Moreover, this method identified novel spatio-temporal features associated with different stages of embryo gastrulation, and elucidated a complex paracrine mechanism capable of explaining spatiotemporal pattern kinetic differences in ESC aggregates of different sizes. PMID:26095427

  6. How Older Rural Adults Utilize Self-Directed Learning in Late Life Adjustments

    ERIC Educational Resources Information Center

    Roberson, Donald N., Jr.

    2003-01-01

    The increasing numbers and influence of older adults is causing many segments of western society to re-evaluate the concept of old age. Medical advances and personal lifestyles have resulted in older adults living longer and healthier lives. As one ages, adjustments in work, family, and health must be made. Self-directed learning (SDL) is one way…

  7. What Drives Students' Self-Directed Learning in a Hybrid PBL Curriculum

    ERIC Educational Resources Information Center

    Lee, Young-Mee; Mann, Karen V.; Frank, Blye W.

    2010-01-01

    Evidence supporting Problem-based learning (PBL) fostering students' self-directed learning (SDL) in hybrid PBL curricula is inconsistent. To explore the influence of PBL in a hybrid curriculum on students' SDL, the authors investigated the following: (1) students' self-assessed SDL ability, (2) students' perceptions of the influence of curricular…

  8. Self-Directed Learning Needs, Patterns, and Outcomes among General Surgeons

    ERIC Educational Resources Information Center

    Gagliardi, Anna R.; Wright, Frances C.; Victor, J. Charles; Brouwers, Melissa C.; Silver, Ivan L.

    2009-01-01

    Introduction: To explore the relationship between self-directed learning (SDL) needs, patterns, barriers, and outcomes among nonacademic general surgeons. Methods: Participants dictated details of SDL episodes associated with cancer patient management from October 2007 to March 2008. Transcripts were coded thematically. Frequencies were calculated…

  9. A Thematic Analysis of the Self-Directed Learning Experiences of 13 Breast Cancer Patients

    ERIC Educational Resources Information Center

    Rager, Kathleen

    2004-01-01

    Although self-directed learning is a common response for many of the 183000 American women who are diagnosed with breast cancer each year, very little is known about the nature of the experience for them. Four themes emerged from interviews with 13 breast cancer patients describing their self-education efforts in regard to their disease. A…

  10. Assessing readiness for self-directed learning within a non-traditional nursing cohort.

    PubMed

    Phillips, Brian N; Turnbull, Beverley J; He, Flora X

    2015-03-01

    Increasing deregulation of the Australian tertiary system has led to changes in entry behaviours anticipated in non-traditional student cohorts. Many nursing students are returning to formal studies later in their lives seeking a career change. Accessibility and flexible study paths make external study increasingly attractive. However external studies require a level of commitment and willingness to develop self-direction and a capacity for resilience. This study sought to elicit the level of self-directed learning readiness (SDLR) among undergraduate nursing students currently enrolled at a bachelor level, and to elicit what differences existed in the levels of SDLR in relation to age, gender, academic year, and previous qualifications. An online survey questionnaire was utilised based on the Self-directed Learning Readiness Scale for Nursing Education. In contrast to earlier work, the participant profile in this study was predominantly non-traditional and captured participants from all three years of the nursing programme. Results found no significant age or gender differences. First year students demonstrated lower levels of self-directed learning readiness. However, unexpected results were demonstrated in the survey subscales in relation to previous qualifications. Participants who already held post-graduate qualifications showed lower scores for Self-Management than those who held diploma qualifications, while students who already held a bachelor's degree had the highest scores in Desire for Learning. The study findings suggest that universities should not assume that SDL capability is dependent on mature age or length of exposure to tertiary study. PMID:25620290

  11. Guideposts to Self-Directed Learning. Expert Commentary on Essential Concepts.

    ERIC Educational Resources Information Center

    Confessore, Gary J., Ed.; Confessore, Sharon J., Ed.

    The 15 chapters in this book include commentaries on 12 seminal works on self-directed learning (SDL) by Houle, Knowles, Tough, Spear and Mocker, Brookfield, Caffarella and O'Donnell, and Long et al. These works were identified by a Delphi panel of 49 experts. Chapter titles and authors are as follows: "An Introduction to the Study of…

  12. Developing Self-Directed Executive Functioning: Recent Findings and Future Directions

    ERIC Educational Resources Information Center

    Barker, Jane E.; Munakata, Yuko

    2015-01-01

    How do children become increasingly self-directed across development, achieving their goals without help from others? How might such developments be impacted by societal changes in how children spend their time? Children's abilities to achieve their goals are supported by developing executive functions (EFs), cognitive processes that predict…

  13. Is (Self-Directed) Learning the Key Skill for Tomorrow's Engineers?

    ERIC Educational Resources Information Center

    Bary, Raphael; Rees, Michael

    2006-01-01

    This paper shows how a study in educational sciences focused on the concept of "competence" can bring about changes in the pedagogical methods used when training engineers. Instead of using personality traits to understand innovators, a PhD study focused on practices and competencies revealed that, amongst other things, self-directed learning…

  14. Individually Guided Motivation: Goal-Setting Procedures to Develop Student Self-Direction and Prosocial Behaviors.

    ERIC Educational Resources Information Center

    Klausmeier, Herbert J.; And Others

    This paper describes research and development activities dealing with a system of individually guided motivation at a Wisconsin elementary school. Four general objectives for the project are stated. These deal with motivation for learning subject matter knowledge and skills, developing independence, assuming increasing self direction, and…

  15. Developing and Piloting an App for Managing Self-Directed Language Learning: An Action Research Approach

    ERIC Educational Resources Information Center

    Lammons, Elizabeth; Momata, Yuko; Mynard, Jo; Noguchi, Junko; Watkins, Satoko

    2015-01-01

    Paper-based tools such as self-evaluation activities, learning plans, reflective journals and learning logs are commonplace for managing Self-Directed Language Learning (SDLL). Such tools not only promote ownership over learning and provide a sense of achievement to learners, but they also promote reflection and raise awareness of learning…

  16. Development and Initial Validation of the Self-Directed Learning Inventory with Korean College Students

    ERIC Educational Resources Information Center

    Suh, Han Na; Wang, Kenneth T.; Arterberry, Brooke J.

    2015-01-01

    This article describes the development and psychometric evaluation of the Self-Directed Learning Inventory (SDLI) tailored to Korean college students, based on study evidences of differences in learning behavior across culture and educational level. With a sample of 605 female college students in Korea, exploratory factor analysis (EFA) results…

  17. The Influence of Item Response Indecision on the Self-Directed Search

    ERIC Educational Resources Information Center

    Sampson, James P., Jr.; Shy, Jonathan D.; Hartley, Sarah Lucas; Reardon, Robert C.; Peterson, Gary W.

    2009-01-01

    Students (N = 247) responded to Self-Directed Search (SDS) per the standard response format and were also instructed to record a question mark (?) for items about which they were uncertain (item response indecision [IRI]). The initial responses of the 114 participants with a (?) were then reversed and a second SDS summary code was obtained and…

  18. Psychometric Properties of the Chinese Self-Directed Search (1994 Edition)

    ERIC Educational Resources Information Center

    Yang, Weiwei; Lance, Charles E.; Hui, Harry C.

    2006-01-01

    In this study, we (a) examined the measurement equivalence/invariance (ME/I) of the Chinese Self-Directed Search (SDS; 1994 edition) across gender and geographic regions (Mainland China vs. Hong Kong); (b) assessed the construct validity of the Chinese SDS using Widaman's (1985, 1992) MTMM framework; and (c) determined whether vocational interests…

  19. On the Performance of Self-Directed Learning within the French Continuing Vocational Training System.

    ERIC Educational Resources Information Center

    Dif, M'Hamed

    Continuing vocational training (CVT) was officially introduced and codified in France in 1971 to promote individuals' employability, career development, and job flexibility. Self-directed learning was initially considered among the most important instruments for its implementation in addition to employer-directed CVT. Despite increased and…

  20. Congruency between Occupational Daydreams and Self Directed Search (SDS) Scores among College Students

    ERIC Educational Resources Information Center

    Miller, Mark J.; Springer, Thomas P.; Tobacyk, Jerome; Wells, Don

    2004-01-01

    In this study, the relationship of expressed occupational daydreams and scores on the Self-Directed Search (SDS) were examined. Results were consistent with Holland's theory of careers. Implications for career counselors are discussed. Students were asked to provide specific biographical data (i. e., age, gender, race) and to write down their…

  1. The Design of a Web-Based Course for Self-Directed Learning

    ERIC Educational Resources Information Center

    Liu, Mingzhuo

    2009-01-01

    Purpose: The purpose of this paper is to explore how to design a web-based course in the context of China for self-directed learning from four perspectives--i.e. pedagogical, psychological, social and technological--and also to summarize the design principles for the web-based course. Design/methodology/approach: The paper reviews literature…

  2. Encouraging Self-Directed Group Learning through an E-Portfolio System

    ERIC Educational Resources Information Center

    Fukuda, Eri; Suzuki, Mitsuko; Hashimoto, Shinichi; Okazak, Hironobu

    2014-01-01

    In this study, the researchers examined how 64 university students engaged in self-directed group learning and used a self-developed e-portfolio system. A sixweek event was held where the students made entries to the e-portfolio individually each week, received feedback from advisors, studied in groups on a voluntary basis, and reflected on their…

  3. Dynamic Training Elements in a Circuit Theory Course to Implement a Self-Directed Learning Process

    ERIC Educational Resources Information Center

    Krouk, B. I.; Zhuravleva, O. B.

    2009-01-01

    This paper reports on the implementation of a self-directed learning process in a circuit theory course, incorporating dynamic training elements which were designed on the basis of a cybernetic model of cognitive process management. These elements are centrally linked in a dynamic learning frame, created on the monitor screen, which displays the…

  4. Fostering Postgraduate Student Engagement: Online Resources Supporting Self-Directed Learning in a Diverse Cohort

    ERIC Educational Resources Information Center

    Mello, Luciane V.

    2016-01-01

    The research question for this study was: "Can the provision of online resources help to engage and motivate students to become self-directed learners?" This study presents the results of an action research project to answer this question for a postgraduate module at a research-intensive university in the United Kingdom. The analysis of…

  5. Twin Similarities in Holland Types as Shown by Scores on the Self-Directed Search

    ERIC Educational Resources Information Center

    Chauvin, Ida; McDaniel, Janelle R.; Miller, Mark J.; King, James M.; Eddlemon, Ondie L. M.

    2012-01-01

    This study examined the degree of similarity between scores on the Self-Directed Search from one set of identical twins. Predictably, a high congruence score was found. Results from a biographical sheet are discussed as well as implications of the results for career counselors.

  6. Verification of Accurate Technical Insight: A Prerequisite for Self-Directed Surgical Training

    ERIC Educational Resources Information Center

    Hu, Yinin; Kim, Helen; Mahmutovic, Adela; Choi, Joanna; Le, Ivy; Rasmussen, Sara

    2015-01-01

    Simulation-based surgical skills training during preclinical education is a persistent challenge due to time constraints of trainees and instructors alike. Self-directed practice is resource-efficient and flexible; however, insight into technical proficiency among trainees is often lacking. The purpose of this study is to prospectively assess the…

  7. Relinquishing Power in the Classroom: A Case Study on Self-Directed Teams in the Classroom.

    ERIC Educational Resources Information Center

    Driskill, Gerald W.; Polansky, Brian

    The shift toward self-directed work teams in organizations is well documented and is further underscored by models that give teamwork an integral role in accomplishing organizational goals. The traditional classroom fails to mirror such shifts when it emphasizes instructor control and decision making with a premium placed on clarity in direction,…

  8. The Self-Directed Learning Experience of Mothers Whose Child Has Had a Paediatric Stroke

    ERIC Educational Resources Information Center

    Grover, Kenda S.

    2014-01-01

    This study employed qualitative research methodology to explore the experiences of mothers who self-directed their learning following their child's stroke diagnosis. Paediatric stroke, although rare, is among the top 10 causes of death in children in the USA, but information about the cause, treatment and long-term impact are difficult to…

  9. Predictors of Differential Response to Cognitive, Experiential, and Self-Directed Psychotherapeutic Procedures.

    ERIC Educational Resources Information Center

    Beutler, Larry E.; And Others

    1991-01-01

    Compared group cognitive therapy (CT); focused expressive psychotherapy; and supportive, self-directed therapy (S/SD) among 63 patients with major depressive disorder. Results suggest that patient characteristics can be used differentially to assign psychotherapy types. Externalizing patients and low defensive patients improved more in CT;…

  10. Self-Directed Learning: Adult Learners' Perceptions and Their Study Materials.

    ERIC Educational Resources Information Center

    Greyling, E. S. G.; Geyser, H. C.; Fourie, C. M.

    2002-01-01

    Triggered by the poor performance of historically-disadvantaged students in a South African distance education course, examined students' perceptions of their self-directed learning (SDL). Also examined the SDL support contained in their study materials. Found that the students generally lacked readiness for SDL, suggesting several changes needed…

  11. A HIM-G Interaction Process Analysis Study of Facilitator--and Self-Directed Groups

    ERIC Educational Resources Information Center

    Conyne, Robert K.; Rapin, Lynn S.

    1977-01-01

    This study of group process evaluated the relative effectiveness of facilitator-directed (FD) and self-directed (SD) personal growth group treatments in inducing change in the level of group member interaction. Examination of treatment effectiveness was accomplished through an interaction process analysis approach, the Hill Interaction…

  12. Facilitator--and Self-Directed Groups: A Statement-by-Statement Interaction Study

    ERIC Educational Resources Information Center

    Conyne, Robert K.; Rapin, Lynn S.

    1977-01-01

    This study compared the effectiveness of facilitator-directed and self-directed personal growth group treatments toward inducing therapeutic verbal interaction. An interaction process analysis approach, the Hill Interaction Matrix (HIM) statement-by-statement system, was used to examine treatment differences. (Author)

  13. Ecology: Learning To Love Our Planet. A Self-Directed Learning Experience. Grades K-8.

    ERIC Educational Resources Information Center

    Enz, Judith; Diffenderfer, Susan

    This self-directed study unit for grades K-3 and 4-8 was developed expressly to transport the student from the position of passive recipient to active participant in his/her own pursuit of knowledge. Within the guide are two complete units: one created for the lower elementary student and one for the upper elementary/middle school student. Units…

  14. The Influence of Job Characteristics and Self-Directed Learning Orientation on Workplace Learning

    ERIC Educational Resources Information Center

    Raemdonck, Isabel; Gijbels, David; van Groen, Willemijn

    2014-01-01

    Given the increasing importance of learning at work, we set out to examine the factors which influence workplace learning behaviour. The study investigated the influence of the job characteristics from Karasek's Job Demand Control Support model and the personal characteristic self-directed learning orientation on workplace learning. A total…

  15. Students' Perceptions of Self-Directed Learning and Collaborative Learning with and without Technology

    ERIC Educational Resources Information Center

    Lee, K.; Tsai, P.-S.; Chai, C. S.; Koh, J. H. L.

    2014-01-01

    This study explored students' perceptions of self-directed learning (SDL) and collaborative learning (CL) with/without technology in an information and communications technology-supported classroom environment. The factors include SDL, CL, SDL supported by technology, and CL supported by technology. Based on the literature review, this study…

  16. Individualized Instruction in Science, Earth-Space Project, Self-Directed Activities.

    ERIC Educational Resources Information Center

    Kuczma, R. M.

    As a supplement to Learning Activity Packages (LAP) of the earth-space project, this manual presents self-directed activities especially designed for individualized instruction. Besides an introduction to LAP characteristics, sets of instructions are given in connection with the metric system, the earth's dimensions, indirect evidence for atomic…

  17. Determining a Difference in Self-Directed Learning Readiness Using the Survey of Adult Learning Traits

    ERIC Educational Resources Information Center

    Ezell, Diana

    2013-01-01

    The purpose of this study was to measure the self-directed learning of educators and explore the differences between and among the variables of age, level of education, position, school district ratings, levels of poverty and affluence, and gender. The Survey of Adult Learning Traits (SALT) authored by Hogg was used as the instrument to measure…

  18. An Examination of Self-Directed Learning Readiness in Executive-Level Fire Officers

    ERIC Educational Resources Information Center

    Knight, Steven G.

    2012-01-01

    The purpose of this study was to examine the self-directed learning readiness in executive fire officers in relation to the independent variables of personality type, educational attainment, and professional designation. This research utilized a quantitative design. This study utilized the Myers-Briggs Type Indicator (MBTI) and the Self-Directed…

  19. Understanding Responsibility: A Self-Directed Learning Application of the Triangle Model of Responsibility

    ERIC Educational Resources Information Center

    Kohns, Jonathan W.; Ponton, Michael K.

    2006-01-01

    Personal responsibility has long been considered an important component in self-directed learning. And yet, a theoretical understanding of personal responsibility that could lead to meaningful instrumentation has eluded the field. The present study considers the merits of the Triangle Model of Responsibility (TMR) (Schlenker, Britt, Pennington,…

  20. Self-Directed Learning and Prostate Cancer: A Thematic Analysis of the Experiences of Twelve Patients

    ERIC Educational Resources Information Center

    Rager, Kathleen B.

    2006-01-01

    Although self-directed learning is a common response for many of the 232,090 US men who are diagnosed with prostate cancer each year, very little is known about the nature of the experience for them. Four themes emerged from interviews with 12 prostate cancer patients describing their self-education efforts in regard to their disease. A…

  1. Applying Self-Directed Learning Principles in the Technical Training of a High-Risk Industry.

    ERIC Educational Resources Information Center

    Blackwood, Constance C.

    1994-01-01

    Experience with nuclear power plant workers for whom continuing education is mandated yielded techniques for incorporating self-direction to overcome resistance: educate management, involve workers, know the audience, incorporate feedback in training plans, be consistent, use learning contracts, motivate learners, use alternative methods, build…

  2. Using the Self-Directed Search: Career Explorer with High-Risk Middle School Students

    ERIC Educational Resources Information Center

    Osborn, Debra S.; Reardon, Robert C.

    2006-01-01

    The Self-Directed Search: Career Explorer was used with 98 (95% African American) high-risk middle school students as part of 14 structured career groups based on Cognitive Information Processing theory. Results and implications are presented on the outcomes of this program.

  3. Self-Directed Learning: College Students' Technology Preparedness Change in the Last 10 Years

    ERIC Educational Resources Information Center

    Caravello, Michael J.; Jiménez, Joel R.; Kahl, Lois J.; Brachio, Brian; Morote, Elsa-Sofia

    2015-01-01

    This study compares a sample of approximately 44 first year college students in 2005 and 2015 on Long Island, New York, in their technology preparedness and self-directed instruction. The researchers used a survey instrument including demographic information focused upon students' preparation for classroom technology in high school and college.…

  4. An Exploratory Study of Self-Directed Science Concept Learning by Students with Moderate Intellectual Disabilities

    ERIC Educational Resources Information Center

    Jimenez, Bree A.; Browder, Diane M.; Courtade, Ginevra R.

    2009-01-01

    This investigation focused on the effects of a treatment package including multiple exemplar training, time delay, and a self-directed learning prompt (KWHL chart) on students' ability to complete an inquiry lesson independently and generalize to untrained materials. Three middle school students with moderate intellectual disabilities learned to…

  5. Self-Directed Learning and Academic Achievement in Secondary Online Students

    ERIC Educational Resources Information Center

    Carson, Elaine Hendricks

    2012-01-01

    This study examined attributes of self-directed learning (SDL) in students, grades 8 through 12, taking online courses through a state-wide online program in the Southeastern United States. The study investigated whether distinct latent classes of SDL exist; whether there was a significant difference in SDL according to gender, ethnicity, and…

  6. New to Facilitating Self-Directed Learning: The Changing Perceptions of Teachers

    ERIC Educational Resources Information Center

    Lai, Conttia; Gardner, David; Law, Ellie

    2013-01-01

    This paper reports on a study examining the attitudes and perceptions of a group of in-service teachers who are new or relatively new to facilitating self-directed learning (SDL) before and after they taught a course with an integrated SDL component. The study also investigates the impact on those teachers' attitudes of an orientation package…

  7. The Effect of Self-Directed Work Teams on Work Ethic

    ERIC Educational Resources Information Center

    Lim, Doo Hun; Petty, Gregory; Fontan, Johnny; Yoon, Seung Won

    2008-01-01

    The purpose of this study was to compare work ethic of manufacturing machine operators between a self-directed work team and a traditional work team based on four work ethic subscales and identify differences in work ethic based on six demographic factors. The major findings from the study indicated there were significant differences in the work…

  8. Diagnostic Use of Holland's Self-Directed Search with University Students.

    ERIC Educational Resources Information Center

    Christensen, Kathleen C.; Sedlacek, William E.

    This study explores the use of a self-counseling device, Holland's Self-Directed Search (SDS), as a diagnostic tool in identifying students who have encountered difficulties in college but persist in their attendance when they may have been better suited to vocational training programs. Thirty-seven students in the University of Maryland Office of…

  9. Predictors of Self-Directed Learning for Low-Qualified Employees: A Multi-Level Analysis

    ERIC Educational Resources Information Center

    Raemdonck, Isabel; van der Leeden, Rien; Valcke, Martin; Segers, Mien; Thijssen, Jo

    2012-01-01

    Purpose: This study aims to examine which variables at the level of the individual employee and at the company level are predictors of self-directed learning in low-qualified employees. Methodology: Results were obtained from a sample of 408 low-qualified employees from 35 different companies. The companies were selected from the energy sector,…

  10. Development of a Supported Self-Directed Learning Approach for Anatomy Education

    ERIC Educational Resources Information Center

    Findlater, Gordon S.; Kristmundsdottir, Fanney; Parson, Simon H.; Gillingwater, Thomas H.

    2012-01-01

    The ability to deliver sufficient core anatomical knowledge and understanding to medical students with limited time and resources remains a major challenge for anatomy educators. Here, we report the results of switching from a primarily didactic method of teaching to supported self-directed learning for students studying anatomy as part of…

  11. A Journey with Chronic Pain: Self-Directed Learning as Survival

    ERIC Educational Resources Information Center

    King, Kathleen P.

    2014-01-01

    Over the past 20 years in the USA, increased insurance control of healthcare decisions, litigation and regulations, have contributed to a dramatic shift in the doctor-patient relationship and respective responsibilities. This paper presents an autoethnographic study of the self-directed learning (SDL) strategies and patterns used by an individual…

  12. Stages of Learning during a Self-Directed Stress Management Experience

    ERIC Educational Resources Information Center

    Larson, Karl L.

    2015-01-01

    Purpose: The purpose of the study was to document the stages of learning reflected through student journaling during a self-directed experience in stress management, and the relationship of those stages to a historical model. Methods: College students participating in a full-semester course in stress management theory were required to select a…

  13. Individualized Instruction in Science, Time-Space-Matter, Self-Directed Activities.

    ERIC Educational Resources Information Center

    Kuczma, R. M.

    As a supplement to Learning Activity Packages (LAP) on the time-space-matter subject, details are presented for self-directed activities. Major descriptions are given on the background of LAP characteristics, metric system, profile graph construction, spectroscope operation, radiant energy measurement, sunspot effects, density determination,…

  14. Investigating the Relationship between Belief and Action in Self-Directed Language Learning

    ERIC Educational Resources Information Center

    Navarro, Diego; Thornton, Katherine

    2011-01-01

    Employing the principles of a contextual approach to learner belief research and applying it to a self-directed learning context at a Japanese university, this longitudinal study investigates the complex interplay between beliefs and actions and its contribution to the development of language learning skills. Through the triangulation of various…

  15. Practical Experience with Self-Directed Learning in Business and Industry Human Resource Development.

    ERIC Educational Resources Information Center

    Guglielmino, Lucy M.; Guglielmino, Paul J.

    1994-01-01

    Four strategies for overcoming resistance to self-directed learning (SDL) in business and industry are visible company support; internal promotion; easy access, especially through electronic linkages; and formalized use of SDL strategies, such as using learning contracts in performance appraisals. (SK)

  16. Effects of Self-Regulatory Instructional Aids on Self-Directed Study

    ERIC Educational Resources Information Center

    Bednall, Timothy C.; Kehoe, E. James

    2011-01-01

    This study examined the effectiveness of providing instructional support for the self-regulation of a self-directed homework assignment. Across four parallel experiments, university students completed an online module on critical thinking. In Experiment 1, participants who were prompted on a broad spectrum of study strategies showed superior…

  17. Using Self-Directed Video Prompting to Teach Students with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Cannella-Malone, Helen I.; Brooks, David G.; Tullis, Christopher A.

    2013-01-01

    This study examined the effects of self-directed video prompting presented via an iPod Touch on teaching four adolescents with moderate-to-severe intellectual and developmental disabilities two daily living tasks. Students were taught to wash a table using instructor-delivered video prompts. After reaching 80% correct for at least three…

  18. Personalisation of Adult Social Care: Self-Directed Support and the Choice and Control Agenda

    ERIC Educational Resources Information Center

    Kendall, Sophie; Cameron, Ailsa

    2014-01-01

    In 2007, "self-directed support" was introduced in adult social care in England to establish choice and control--in the assessment process itself and over service provision--for "all" service users. The personalisation agenda is underpinned by a range of ideologies, particularly a civil rights empowerment approach and…

  19. An Investigation of the Construct Validity of the Personality Trait of Self-Directed Learning

    ERIC Educational Resources Information Center

    Lounsbury, John W.; Levy, Levy J.; Park, Soo-Hee; Gibson, Lucy W.; Smith, Ryan

    2009-01-01

    Based on samples of 398 middle school students, 568 high school students, and 1159 college students, self-directed learning was found to be related to cumulative grade-point-average at all levels as well as to Big Five personality traits (Openness, Conscientiousness, Emotional Stability, and Extraversion), narrow personality traits (Optimism,…

  20. Using Two Different Self-Directed Search (SDS) Interpretive Materials: Implications for Career Assessment

    ERIC Educational Resources Information Center

    Dozier, V. Casey; Sampson, James P.; Reardon, Robert C.

    2013-01-01

    John Holland's Self-Directed Search (SDS) is a career assessment that consists of several booklets designed to be self-scored and self-administered. It simulates what a practitioner and an individual might do together in a career counseling session (e.g., review preferred activities and occupations; review competencies, abilities and possible…

  1. A Phenomenological Exploration of Self-Directed Learning among Successful Minority Entrepreneurs

    ERIC Educational Resources Information Center

    Alexander, Nancy Hope

    2013-01-01

    This transcendental, phenomenological study explored the Self-directed learning (SDL) of 10 successful minority entrepreneurs. Two SDL theories serve as lenses for the study, Spear and Mocker's (1984) Organizing Circumstance and Brockett and Heimstra's (1991) Personal Responsibility Orientation model. Five themes emerged from the data:…

  2. Status and trends in the direct support workforce in self-directed supports.

    PubMed

    Bogenschutz, Matthew; Hewitt, Amy; Hall-Lande, Jennifer; LaLiberte, Traci

    2010-10-01

    Self-directed programs that allow individuals with intellectual and developmental disabilities to exercise greater control over their finances have become increasingly common in recent years. At the same time, challenges in the recruitment, retention, and training of direct support workers in the field have grown more acute. In this article, the authors investigate the status of the direct support workforce for people using self-directed supports in 1 Midwestern state, based on the results of a statewide survey of service users. Although additional research is needed, the results of this study suggest that people who use self-directed funding options are satisfied with their ability to direct staffing, though challenges remain. Among these challenges, the presence of higher than expected wages but lower than expected benefits provision compared with traditional services may have serious policy and staff retention ramifications that affect the long-term viability of self-directed funding options. In addition, staff training remains a challenge, with service users in this sample reporting low rates of training beyond a general skill set. Implications of these findings are discussed. PMID:20973698

  3. Evaluating the Effects of Competency-Based Web Learning on Self-Directed Learning Aptitudes

    ERIC Educational Resources Information Center

    Chang, Chi-Cheng

    2007-01-01

    The main aim of the study is to evaluate the impact of the competency-based web learning material (CBWLM) on the self-directed learning aptitude (SDLA) of college students. Specifically, it seeks to investigate, statistically, the changes in SDLAs at different stages of competency-based web learning (CBWL) over an eight-week period. The sample of…

  4. The Relative Influence of Different Domains of Social Connectedness on Self-Directed Violence in Adolescence

    ERIC Educational Resources Information Center

    Kaminski, Jennifer W.; Puddy, Richard W.; Hall, Diane M.; Cashman, Sandra Y.; Crosby, Alexander E.; Ortega, LaVonne A. G.

    2010-01-01

    Previous research has linked greater social connectedness with a lowered risk of self-directed violence among adolescents. However, few studies have analyzed the comparative strength of different domains of connectedness (e.g., family, peers and school) to determine where limited resources might best be focused. Data to address that gap were taken…

  5. The Power of Self-Directed Journals: Being a Temporary "Other" for Learning to Teach

    ERIC Educational Resources Information Center

    Matsumoto, Yumi

    2016-01-01

    This case study investigates how an ESL teacher's activity of self-directed journal writing can facilitate learning and function as a mediational tool for teacher professional development. The participant for this study is a native English speaker who taught an ESL freshman writing course in an American university. Since he had little time to…

  6. Iranian Clinical Nurses’ Activities for Self-Directed Learning: A Qualitative Study

    PubMed Central

    Ghiyasvandian, Shahrzad; Malekian, Morteza; Cheraghi, Mohammad Ali

    2016-01-01

    Background: Clinical nurses need lifelong learning skills for responding to the rapid changes of clinical settings. One of the best strategies for lifelong learning is self-directed learning. The aim of this study was to explore Iranian clinical nurses’ activities for self-directed learning. Methods: In this qualitative study, 23 semi-structured personal interviews were conducted with nineteen clinical nurses working in all four hospitals affiliated to Isfahan Social Security Organization, Isfahan, Iran. Study data were analyzed by using the content analysis approach. The study was conducted from June 2013 to October 2014. Findings: Study participants’ activities for self-directed learning fell into two main categories of striving for knowledge acquisition and striving for skill development. The main theme of the study was ‘Revising personal performance based on intellectual-experiential activities’. Conclusions: Study findings suggest that Iranian clinical nurses continually revise their personal performance by performing self-directed intellectual and experiential activities to acquire expertise. The process of acquiring expertise is a linear process which includes two key steps of knowledge acquisition and knowledge development. In order to acquire and advance their knowledge, nurses perform mental learning activities such as sensory perception, self-evaluation, and suspended judgment step-by-step. Moreover, they develop their skills through doing activities like apprenticeship, masterly performance, and self-regulation. The absolute prerequisite to expertise acquisition is that a nurse needs to follow these two steps in a sequential manner. PMID:26652072

  7. Status and Trends in the Direct Support Workforce in Self-Directed Supports

    ERIC Educational Resources Information Center

    Bogenschutz, Matthew; Hewitt, Amy; Hall-Lande, Jennifer; LaLiberte, Traci

    2010-01-01

    Self-directed programs that allow individuals with intellectual and developmental disabilities to exercise greater control over their finances have become increasingly common in recent years. At the same time, challenges in the recruitment, retention, and training of direct support workers in the field have grown more acute. In this article, the…

  8. Reflective Teaching as Self-Directed Professional Development: Building Practical or Work-Related Knowledge

    ERIC Educational Resources Information Center

    Minott, Mark A.

    2010-01-01

    The broad purpose of this self-study is two-fold: first, to aid in redressing the lack of attention given to the professional development of teacher educators; and second, to forward the idea that teaching reflectively is not only an excellent framework through which self-directed professional development can be enacted, but it is also an…

  9. An Examination of the Self-Directed Learning Practices of ESL Adult Language Learners

    ERIC Educational Resources Information Center

    Grover, Kendra S.; Miller, Michael T.; Swearingen, Brent; Wood, Nancy

    2014-01-01

    Self-directed learning is one of the preeminent theories in the field of adult education. This study explored how English as a Second Language learners directed their own learning outside of the formal classroom through the use of practices that potentially advance their English language proficiency. Results from a survey of over 400 ESL students…

  10. The Effect of Self-Directed Work Teams on Work Ethic

    ERIC Educational Resources Information Center

    Petty, Gregory C.; Lim, Doo Hun; Yoon, Seung Won; Fontan, Johnny

    2008-01-01

    This study examined the work ethic of manufacturing machine operators between self-directed work teams and traditional work groups using four work ethic subscales: dependable, considerate, ambitious, and cooperative (Dawson, [1999]; Petty, [1991]). Differences in measured work ethic scores were also compared across six demographic variables: age,…

  11. Self-Directed Learning and Guidance in Non-Formal Open Courses

    ERIC Educational Resources Information Center

    Ponti, Marisa

    2014-01-01

    Digital media and open educational resources (OER) are said to redraw the boundaries between learners and teachers, by weakening the centralization of expertise and the distribution of subject-matter authority. This paper presents the findings of an ethnographic study of how the use of OER mediates the relations between self-directed learners and…

  12. e-Portfolios Enhancing Students' Self-Directed Learning: A Systematic Review of Influencing Factors

    ERIC Educational Resources Information Center

    Beckers, Jorrick; Dolmans, Diana; Van Merriënboer, Jeroen

    2016-01-01

    e-Portfolios have become increasingly popular among educators as learning tools. Some research even shows that e-portfolios can be utilised to facilitate the development of skills for self-directed learning. Such skills include self-assessment of performance, formulation of learning goals, and selection of future tasks. However, it is not yet…

  13. Responses of fibroblasts to anchorage of dorsal extracellular matrix receptors.

    PubMed

    Beningo, Karen A; Dembo, Micah; Wang, Yu-li

    2004-12-28

    Fibroblasts in 2D cultures differ dramatically in behavior from those in the 3D environment of a multicellular organism. However, the basis of this disparity is unknown. A key difference is the spatial arrangement of anchored extracellular matrix (ECM) receptors to the ventral surface in 2D cultures and throughout the entire surface in 3D cultures. Therefore, we asked whether changing the topography of ECM receptor anchorage alone could invoke a morphological response. By using polyacrylamide-based substrates to present anchored fibronectin or collagen on dorsal cell surfaces, we found that well spread fibroblasts in 2D cultures quickly changed into a bipolar or stellate morphology similar to fibroblasts in vivo. Cells in this environment lacked lamellipodia and large actin bundles and formed small focal adhesions only near focused sites of protrusion. These responses depend on substrate rigidity, calcium ion, and, likely, the calcium-dependent protease calpain. We suggest that fibroblasts respond to both spatial distribution and mechanical input of anchored ECM receptors. Changes in cell shape may in turn affect diverse cellular activities, including gene expression, growth, and differentiation, as shown in numerous previous studies. PMID:15601776

  14. Exploring first-year undergraduate medical students' self-directed learning readiness to physiology.

    PubMed

    Abraham, Reem Rachel; Fisher, Murray; Kamath, Asha; Izzati, T Aizan; Nabila, Saidatul; Atikah, Nik Nur

    2011-12-01

    Medical students are expected to possess self-directed learning skills to pursue lifelong learning. Previous studies have reported that the readiness for self-directed learning depends on personal attributes as well as the curriculum followed in institutions. Melaka Manipal Medical College of Manipal University (Karnataka, India) offers a Bachelor of Medicine and Bachelor of Surgery (MBBS) twinning program that is of 5 yr in duration. Keeping in mind the amount of time that the curriculum has devoted for self-directed learning, we explored the self-directed learning readiness of first-year MBBS students (n = 130) using a self-directed learning readiness scale (SDLRS) and explored the correlation between SDLRS scores of high achievers, medium achievers, and low achievers with their academic performance in physiology examinations. Students were requested to respond to each item of the SDLRS on a Likert scale. Median scores of the three scales of the SDLRS were compared across the three groups of students using a Kruskall-Wallis test. SDLRS scores of the students (n = 130) were correlated with their marks in theory papers of first, second, and third block-end examinations using Spearmann's correlation coefficient. The mean item score for desire for learning was found to be higher followed by self-control and self-management. Data analyses showed significantly high (P < 0.03) median scores for self-control for high achievers compared with medium and low achievers. Between the groups, high achievers had a higher score for all the three scales of the SDLRS followed by low and medium achievers. SDLRS scores and academic performance of the three groups of students were found to exhibit a weak correlation. This study threw light on the fact that despite having a high desire for learning and ability of self-control, students need to be supported in their self-management skills. PMID:22139776

  15. Less-structured time in children's daily lives predicts self-directed executive functioning

    PubMed Central

    Barker, Jane E.; Semenov, Andrei D.; Michaelson, Laura; Provan, Lindsay S.; Snyder, Hannah R.; Munakata, Yuko

    2014-01-01

    Executive functions (EFs) in childhood predict important life outcomes. Thus, there is great interest in attempts to improve EFs early in life. Many interventions are led by trained adults, including structured training activities in the lab, and less-structured activities implemented in schools. Such programs have yielded gains in children's externally-driven executive functioning, where they are instructed on what goal-directed actions to carry out and when. However, it is less clear how children's experiences relate to their development of self-directed executive functioning, where they must determine on their own what goal-directed actions to carry out and when. We hypothesized that time spent in less-structured activities would give children opportunities to practice self-directed executive functioning, and lead to benefits. To investigate this possibility, we collected information from parents about their 6–7 year-old children's daily, annual, and typical schedules. We categorized children's activities as “structured” or “less-structured” based on categorization schemes from prior studies on child leisure time use. We assessed children's self-directed executive functioning using a well-established verbal fluency task, in which children generate members of a category and can decide on their own when to switch from one subcategory to another. The more time that children spent in less-structured activities, the better their self-directed executive functioning. The opposite was true of structured activities, which predicted poorer self-directed executive functioning. These relationships were robust (holding across increasingly strict classifications of structured and less-structured time) and specific (time use did not predict externally-driven executive functioning). We discuss implications, caveats, and ways in which potential interpretations can be distinguished in future work, to advance an understanding of this fundamental aspect of growing up

  16. Self-directed interventions to promote weight loss: a systematic review and meta-analysis.

    PubMed

    Tang, Jason C H; Abraham, Charles; Greaves, Colin J; Nikolaou, Vasilis

    2016-09-01

    Many self-directed weight-loss interventions have been developed using a variety of delivery formats (e.g., internet and smartphone) and change techniques. Yet, little research has examined whether self-directed interventions can exclusively promote weight loss. MEDLINE, Embase, PsycINFO, CINAHL, and the Cochrane Library were systematically reviewed for randomised controlled trials evaluating self-directed interventions in relation to weight-loss outcomes in adults. Standardised mean differences (SMD) and 95% confidence intervals (CI) were calculated using a random effects model. Twenty-seven trials incorporating 36 comparisons met our inclusion criteria. Participants using self-directed interventions lost significantly more weight (MD = -1.56 kg, CI -2.25, -0.86 ranging from 0.6 to 5.3 kg) compared to those in the minimal intervention or no-treatment groups (3.1-month follow-up median). The majority of interventions were internet based (18 evaluations) and these were effective at 3 months (MD = -1.74 kg, CI -2.65, -0.82 ranging from 0.6 to 4.8 kg) (SMD = -0.48, 95% CI -0.72, -0.24, I(2) = 82%; p < .0001; 16 evaluations) and 6 months follow-up (MD = -2.71 kg, CI -4.03, -1.39 ranging from 2.2 to 5.3 kg) (SMD = -0.59, 95% CI -0.99, -0.19, I(2) = 76%; p = .004; 4 evaluations). Self-directed weight-loss interventions can generate modest weight loss for up to 6 months but may need to be supplemented by other interventions to achieve sustained and clinically meaningful weight loss. PMID:27091296

  17. Experimental evolution of an alternating uni- and multicellular life cycle in Chlamydomonas reinhardtii

    PubMed Central

    Ratcliff, William C.; Herron, Matthew D.; Howell, Kathryn; Pentz, Jennifer T.; Rosenzweig, Frank; Travisano, Michael

    2013-01-01

    The transition to multicellularity enabled the evolution of large, complex organisms, but early steps in this transition remain poorly understood. Here we show that multicellular complexity, including development from a single cell, can evolve rapidly in a unicellular organism that has never had a multicellular ancestor. We subject the alga Chlamydomonas reinhardtii to conditions that favour multicellularity, resulting in the evolution of a multicellular life cycle in which clusters reproduce via motile unicellular propagules. While a single-cell genetic bottleneck during ontogeny is widely regarded as an adaptation to limit among-cell conflict, its appearance very early in this transition suggests that it did not evolve for this purpose. Instead, we find that unicellular propagules are adaptive even in the absence of intercellular conflict, maximizing cluster-level fecundity. These results demonstrate that the unicellular bottleneck, a trait essential for evolving multicellular complexity, can arise rapidly via co-option of the ancestral unicellular form. PMID:24193369

  18. Fibroblast biology in pterygia.

    PubMed

    Kim, Kyoung Woo; Park, Soo Hyun; Kim, Jae Chan

    2016-01-01

    Activation of fibroblasts is a vital process during wound healing. However, if prolonged and exaggerated, profibrotic pathways lead to tissue fibrosis or scarring and further organ malfunction. Although the pathogenesis of pterygium is known to be multi-factorial, additional studies are needed to better understand the pathways initiated by fibroblast activation for the purpose of therapeutic translation. Regarding pterygium as a possible systemic disorder, we discuss the different cell types that pterygium fibroblasts originate from. These may include bone marrow-derived progenitor cells, cells undergoing epithelial-mesenchymal transition (EMT), and local resident stromal cells. We also describe how pterygium fibroblasts can be activated and perpetuate profibrotic signaling elicited by various proliferative drivers, immune-inflammation, and novel factors such as stromal cell-derived factor-1 (SDF-1) as well as a known key fibrotic factor, transforming growth factor-beta (TGF-β). Finally, epigenetic modification is discussed to explain inherited susceptibility to pterygium. PMID:26675401

  19. Waltzing Volvox/: Orbiting Bound States of Flagellated Multicellular Algae

    NASA Astrophysics Data System (ADS)

    Drescher, K.; Leptos, K.; Pedley, T. J.; Goldstein, R. E.; Ishikawa, T.

    2008-11-01

    The spherical colonial alga Volvox swims by means of flagella on thousands of surface somatic cells. This geometry and its large size makes it a model organism for the fluid dynamics of multicellularity. Remarkably, when two nearby colonies swim close to a solid surface, they are attracted together and can form a stable bound state in which they continuously waltz around each other. A surface-mediated hydrodynamic attraction between colonies combined with the rotational motion of bottom-heavy Volvox are shown to explain the stability and dynamics of the bound state. This phenomenon is suggested to underlie observed clustering of colonies at surfaces.

  20. The Birth of Animal Development: Multicellularity and the Germline.

    PubMed

    Woodland, Hugh R

    2016-01-01

    The evolution of multicellular animals has been attributed to many kinds of selective advantage; here I suggest that the evolution of somatic cells to feed and protect the germline was central to the appearance of animals. This would have been driven by selection for extreme anisogamy-the evolution of sperm and egg. Evidence is adduced from the germline stem cells of simple animals (defining germline as any cell that normally produces the next generation via the sexual process) and from the control circuitry ubiquitous in animal germlines. With the soma and its elaboration came animal development, as we understand it. PMID:26970004

  1. The Relationships Between Self-Directed Learning, Critical Thinking, and Psychological Type, and Some Implications for Teaching in Higher Education.

    ERIC Educational Resources Information Center

    Kreber, Carolin

    1998-01-01

    A study explored the extent to which 142 undergraduate students' willingness and perceived capacity to engage in self-directed learning, and ability to think critically, were explained by psychological type. Results indicate extroverted intuition is a strong predictor for self-directed learning; psychological type did not predict critical…

  2. A Preliminary Investigation of Self-Directed Learning Activities in a Non-Formal Blended Learning Environment

    ERIC Educational Resources Information Center

    Schwier, Richard A.; Morrison, Dirk; Daniel, Ben K.

    2009-01-01

    This research considers how professional participants in a non-formal self-directed learning environment (NFSDL) made use of self-directed learning activities in a blended face-to-face and on line learning professional development course. The learning environment for the study was a professional development seminar on teaching in higher education…

  3. Examining the Early Evidence for Self-Directed Marriage and Relationship Education: A Meta-Analytic Study

    ERIC Educational Resources Information Center

    McAllister, Shelece; Duncan, Stephen F.; Hawkins, Alan J.

    2012-01-01

    This meta-analysis examines the efficacy of self-directed marriage and relationship education (MRE) programs on relationship quality and communication skills. Programs combining traditional face-to-face learning with self-directed elements are also examined, and traditional programs' effectiveness is included as a comparison point. Sixteen studies…

  4. Exploring Self-Directed Learning in the Online Learning Environment: Comparing Traditional versus Nontraditional Learner Populations a Qualitative Study

    ERIC Educational Resources Information Center

    Plews, Rachel Christine

    2016-01-01

    The purpose of this study was to explore self-directed learning in the online learning context. A sample of traditional and nontraditional learners, who were considered above average in their level of self-direction, participated in qualitative interviews to discuss their learning while engaged in an online course. The findings suggested no major…

  5. Understanding Faculty and Non-Traditional Student Perceptions of Self-Directed Learning in a Practical Nursing Program

    ERIC Educational Resources Information Center

    Rogers, Carmen

    2013-01-01

    This study was designed to identify and investigate nursing faculty and student perspectives of self-directed learning in a practical nursing program. It also explored the degree to which student's perceptions of self-directed learning exhibited factors consistent with that of critical thinking. This study is important because self-directed…

  6. The Nature of Self-Directed Learning and Transformational Learning in Self-Managing Bipolar Disorder to Stay Well

    ERIC Educational Resources Information Center

    Francik, Wendy A.

    2012-01-01

    The purpose of the research was to explore the self-directed learning and transformational learning experiences among persons with bipolar disorder. A review of previous research pointed out how personal experiences with self-directed learning and transformational learning facilitated individuals' learning to manage HIV, Methicillan-resitant…

  7. The Relationship between Engineering Students' Self-Directed Learning Abilities and Online Learning Performances: A Pilot Study

    ERIC Educational Resources Information Center

    Chou, Pao-Nan

    2012-01-01

    This study aimed to explore engineering students' self-directed learning abilities in an online learning environment. The research centered on the correlation relationship between students' self-directed learning abilities and learning outcomes. The instructional activity in one experimental study was to simulate an online learning task in the…

  8. Cancer across the tree of life: cooperation and cheating in multicellularity

    PubMed Central

    Aktipis, C. Athena; Boddy, Amy M.; Jansen, Gunther; Hibner, Urszula; Hochberg, Michael E.; Maley, Carlo C.; Wilkinson, Gerald S.

    2015-01-01

    Multicellularity is characterized by cooperation among cells for the development, maintenance and reproduction of the multicellular organism. Cancer can be viewed as cheating within this cooperative multicellular system. Complex multicellularity, and the cooperation underlying it, has evolved independently multiple times. We review the existing literature on cancer and cancer-like phenomena across life, not only focusing on complex multicellularity but also reviewing cancer-like phenomena across the tree of life more broadly. We find that cancer is characterized by a breakdown of the central features of cooperation that characterize multicellularity, including cheating in proliferation inhibition, cell death, division of labour, resource allocation and extracellular environment maintenance (which we term the five foundations of multicellularity). Cheating on division of labour, exhibited by a lack of differentiation and disorganized cell masses, has been observed in all forms of multicellularity. This suggests that deregulation of differentiation is a fundamental and universal aspect of carcinogenesis that may be underappreciated in cancer biology. Understanding cancer as a breakdown of multicellular cooperation provides novel insights into cancer hallmarks and suggests a set of assays and biomarkers that can be applied across species and characterize the fundamental requirements for generating a cancer. PMID:26056363

  9. Cancer across the tree of life: cooperation and cheating in multicellularity.

    PubMed

    Aktipis, C Athena; Boddy, Amy M; Jansen, Gunther; Hibner, Urszula; Hochberg, Michael E; Maley, Carlo C; Wilkinson, Gerald S

    2015-07-19

    Multicellularity is characterized by cooperation among cells for the development, maintenance and reproduction of the multicellular organism. Cancer can be viewed as cheating within this cooperative multicellular system. Complex multicellularity, and the cooperation underlying it, has evolved independently multiple times. We review the existing literature on cancer and cancer-like phenomena across life, not only focusing on complex multicellularity but also reviewing cancer-like phenomena across the tree of life more broadly. We find that cancer is characterized by a breakdown of the central features of cooperation that characterize multicellularity, including cheating in proliferation inhibition, cell death, division of labour, resource allocation and extracellular environment maintenance (which we term the five foundations of multicellularity). Cheating on division of labour, exhibited by a lack of differentiation and disorganized cell masses, has been observed in all forms of multicellularity. This suggests that deregulation of differentiation is a fundamental and universal aspect of carcinogenesis that may be underappreciated in cancer biology. Understanding cancer as a breakdown of multicellular cooperation provides novel insights into cancer hallmarks and suggests a set of assays and biomarkers that can be applied across species and characterize the fundamental requirements for generating a cancer. PMID:26056363

  10. The Effects of Case-Based Team Learning on Students’ Learning, Self Regulation and Self Direction

    PubMed Central

    Rezaee, Rita; Mosalanejad, Leili

    2015-01-01

    Introduction: The application of the best approaches to teach adults in medical education is important in the process of training learners to become and remain effective health care providers. This research aims at designing and integrating two approaches, namely team teaching and case study and tries to examine the consequences of these approaches on learning, self regulation and self direction of nursing students. Material & Methods: This is aquasi experimental study of 40 students who were taking a course on mental health. The lessons were designed by using two educational techniques: short case based study and team based learning. Data gathering was based on two valid and reliablequestionnaires: Self-Directed Readiness Scale (SDLRS) and the self-regulating questionnaire. Open ended questions were also designed for the evaluation of students’with points of view on educational methods. Results: The Results showed an increase in the students’ self directed learning based on their performance on the post-test. The results showed that the students’ self-directed learning increased after the intervention. The mean difference before and after intervention self management was statistically significant (p=0.0001). Also, self-regulated learning increased with the mean difference after intervention (p=0.001). Other results suggested that case based team learning can have significant effects on increasing students’ learning (p=0.003). Conclusion: This article may be of value to medical educators who wish to replace traditional learning with informal learning (student-centered-active learning), so as to enhance not only the students’ ’knowledge, but also the advancement of long- life learning skills. PMID:25946918