An Es - Profile on Academia.edu (original) (raw)

Papers by An Es

Analyse Harmonique Non-Commutative sur Certain Es-paces Homogen'es

Structures m'etriques pour les Vari'et'es Riemanniennes

Journal of Business Venturing, 1998

Previous research on the psychology of entrepreneurs found that personality traits such as locus ... more Previous research on the psychology of entrepreneurs found that personality traits such as locus of control failed to distinguish entrepreneurs from managers. In search of an individual characteristic that is distinctively entrepreneurial, we proposed an entrepreneurial self-efficacy construct (ESE) to predict the likelihood of an individual being an entrepreneur. ESE refers to the strength of a person's belief that he or she is capable of successfully performing the various roles and tasks of entrepreneurship. It consists of five factors: marketing, innovation, management, risk-taking, and financial control. We conducted two studies, one on students and the other on small business executives. Study 1 found that the total ESE score differentiated entrepreneurship students from students of both management and organizational psychology, and that across the three types of students, ESE was positively related to the intention to set up one's own business. We also found the entrepreneurship students to have higher selfefficacy in marketing, management, and financial control than the management and psychology students. In study 2, we simultaneously tested effects of ESE and locus of control on the criteria of founders vs. nonfounders of current businesses. After controlling for individual and company background variables, This is especially true for sectors of the population such as women or those minority groups who are perceived as lacking entrepreneurial traditions. Communities and individuals could benefit from identifying sources of entrepreneurial avoidance by targeting their efforts toward enhancing ESE of particular groups or individuals for specific aspects of entrepreneurship.

Nature Methods, 2005

Human embryonic stem cells (hESCs) are routinely cultured on fibroblast feeder layers or in fibro... more Human embryonic stem cells (hESCs) are routinely cultured on fibroblast feeder layers or in fibroblast-conditioned medium (CM). Bone morphogenetic proteins (BMPs) have previously been shown to induce hESC differentiation, in apparent contrast to mouse embryonic stem (ES) cells, in which BMP4 synergizes with leukemia inhibitory factor (LIF) to maintain self-renewal. Here we demonstrate that hESCs cultured in unconditioned medium (UM) are subjected to high levels of BMP signaling activity, which is reduced in CM. The BMP antagonist noggin synergizes with basic fibroblast growth factor (bFGF) to repress BMP signaling and sustain undifferentiated proliferation of hESCs in the absence of fibroblasts or CM. These findings suggest a basic difference in the self-renewal mechanism between mouse and human ES cells and simplify the culture of hESCs.

Biochimica Et Biophysica Acta-reviews on Cancer, 2003

The Wnt signaling pathway, named for its most upstream ligands, the Wnts, is involved in various ... more The Wnt signaling pathway, named for its most upstream ligands, the Wnts, is involved in various differentiation events during embryonic development and leads to tumor formation when aberrantly activated. Molecular studies have pinpointed activating mutations of the Wnt signaling pathway as the cause of approximately 90% of colorectal cancer (CRC), and somewhat less frequently in cancers at other sites, such as hepatocellular carcinoma (HCC). Ironically, Wnts themselves are only rarely involved in the activation of the pathway during carcinogenesis. Mutations mimicking Wnt stimulation-generally inactivating APC mutations or activating h-catenin mutations-result in nuclear accumulation of h-catenin which subsequently complexes with T-cell factor/lymphoid enhancing factor (TCF/LEF) transcription factors to activate gene transcription. Recent data identifying target genes has revealed a genetic program regulated by h-catenin/TCF controlling the transcription of a suite of genes promoting cellular proliferation and repressing differentiation during embryogenesis, carcinogenesis, and in the post-embryonic regulation of cell positioning in the intestinal crypts. This review considers the spectra of tumors arising from active Wnt signaling and attempts to place perspective on recent data that begin to elucidate the mechanisms prompting uncontrolled cell growth following induction of Wnt signaling. D

Nature, 2007

Nuclear transplantation can reprogramme a somatic genome back into an embryonic epigenetic state,... more Nuclear transplantation can reprogramme a somatic genome back into an embryonic epigenetic state, and the reprogrammed nucleus can create a cloned animal or produce pluripotent embryonic stem cells. One potential use of the nuclear cloning approach is the derivation of 'customized' embryonic stem (ES) cells for patient-specific cell treatment, but technical and ethical considerations impede the therapeutic application of this technology. Reprogramming of fibroblasts to a pluripotent state can be induced in vitro through ectopic expression of the four transcription factors Oct4 (also called Oct3/ 4 or Pou5f1), Sox2, c-Myc and Klf4. Here we show that DNA methylation, gene expression and chromatin state of such induced reprogrammed stem cells are similar to those of ES cells. Notably, the cells-derived from mouse fibroblasts-can form viable chimaeras, can contribute to the germ line and can generate live late-term embryos when injected into tetraploid blastocysts. Our results show that the biological potency and epigenetic state of in-vitro-reprogrammed induced pluripotent stem cells are indistinguishable from those of ES cells.

Probabilit?es et potentiel

Les Variables Re'gionalise'es et leur Estimation

Evolutionary Computation, 2003

This paper presents a novel evolutionary optimization strategy based on the derandomized evolutio... more This paper presents a novel evolutionary optimization strategy based on the derandomized evolution strategy with covariance matrix adaptation (CMA-ES). This new approach is intended to reduce the number of generations required for convergence to the optimum. Reducing the number of generations, i.e., the time complexity of the algorithm, is important if a large population size is desired: (1) to reduce the effect of noise;

ES&T Special Report: Priority pollutants: Ia perspective view

Environmental Science & Technology, 1979

One objective of this article is to relate the historical origins of EPA's Priority ... more One objective of this article is to relate the historical origins of EPA's Priority Pollutants and the develop-ment of the “Priority Pollutant Pro-tocol.” Most people are unaware of the difficulties involved in providing methods for the necessary analytical support for these pollutants. A ...

Es-tablishing homologies in protein sequences

... Copyright © 2011 Elsevier BV All rights reserved. SciVerse® is a registered trademark of Else... more ... Copyright © 2011 Elsevier BV All rights reserved. SciVerse® is a registered trademark of Elsevier Properties SA, used under license. ScienceDirect® is a registered trademark of Elsevier BV.

Sur le point pour lequel la somme des distances de n points donn~es est minimum

Arthritis and Rheumatism, 1994

Generating green fluorescent mice by germline transmission of green fluorescent ES cells

Mechanisms of Development, 1998

Green fluorescent protein (GFP) and its variants currently represent the only non-invasive marker... more Green fluorescent protein (GFP) and its variants currently represent the only non-invasive markers available for labeling mammalian cells in culture or in a multicellular organism through transgenesis. To date this marker gene has been widely used in the study of many organisms, but as yet has not found large-scale application in mammals due to problems encountered with weak fluorescence and instability of the wild-type protein at higher temperatures. Recently, though, several mutants have been made in the wild-type (wt) GFP so as to improve its thermostability and fluorescence. EGFP (enhanced GFP) is one such wtGFP variant. As a first step in assessing the use of EGFP in ES cell-mediated strategies, we have established a mouse embryonic stem (ES) cell lines expressing EGFP, which can be propagated in culture, reintroduced into mice. or induced to differentiate in vitro, while still maintaining ubiquitous EGFP expression. From the results presented we can suggest that: 1) possible improvements in the efficiency of transgenic regimes requiring the germline transmission of ES cells by aggregation chimeras can be made by the preselection chimeric embryos at the blastocyst stage: (2) the expression of a noninvasive marker, driven by a promoter that is active during early postimplantation development, allows access to embryos during a window of embryonic development that has previously been difficult to investigate (3) the behavior of mutant ES cells can be followed with simple microscopic observation of chimeric embryos or adult animals comprising green fluorescent cells/tissues. and (4) intercrosses of F1 mice and subsequent generations of animals show that progeny can be genotyped by UV light, such that mice homozygous for the transgene can be distinguished from hemizygotes due to their increased fluorescence.

Les In?egalit?es ? Economiques

On the Variances of Asympototically Normal Es-timators From Complex Surveys

Analyse Harmonique Non-Commutative sur Certain Es-paces Homogen'es

Structures m'etriques pour les Vari'et'es Riemanniennes

Journal of Business Venturing, 1998

Previous research on the psychology of entrepreneurs found that personality traits such as locus ... more Previous research on the psychology of entrepreneurs found that personality traits such as locus of control failed to distinguish entrepreneurs from managers. In search of an individual characteristic that is distinctively entrepreneurial, we proposed an entrepreneurial self-efficacy construct (ESE) to predict the likelihood of an individual being an entrepreneur. ESE refers to the strength of a person's belief that he or she is capable of successfully performing the various roles and tasks of entrepreneurship. It consists of five factors: marketing, innovation, management, risk-taking, and financial control. We conducted two studies, one on students and the other on small business executives. Study 1 found that the total ESE score differentiated entrepreneurship students from students of both management and organizational psychology, and that across the three types of students, ESE was positively related to the intention to set up one's own business. We also found the entrepreneurship students to have higher selfefficacy in marketing, management, and financial control than the management and psychology students. In study 2, we simultaneously tested effects of ESE and locus of control on the criteria of founders vs. nonfounders of current businesses. After controlling for individual and company background variables, This is especially true for sectors of the population such as women or those minority groups who are perceived as lacking entrepreneurial traditions. Communities and individuals could benefit from identifying sources of entrepreneurial avoidance by targeting their efforts toward enhancing ESE of particular groups or individuals for specific aspects of entrepreneurship.

Nature Methods, 2005

Human embryonic stem cells (hESCs) are routinely cultured on fibroblast feeder layers or in fibro... more Human embryonic stem cells (hESCs) are routinely cultured on fibroblast feeder layers or in fibroblast-conditioned medium (CM). Bone morphogenetic proteins (BMPs) have previously been shown to induce hESC differentiation, in apparent contrast to mouse embryonic stem (ES) cells, in which BMP4 synergizes with leukemia inhibitory factor (LIF) to maintain self-renewal. Here we demonstrate that hESCs cultured in unconditioned medium (UM) are subjected to high levels of BMP signaling activity, which is reduced in CM. The BMP antagonist noggin synergizes with basic fibroblast growth factor (bFGF) to repress BMP signaling and sustain undifferentiated proliferation of hESCs in the absence of fibroblasts or CM. These findings suggest a basic difference in the self-renewal mechanism between mouse and human ES cells and simplify the culture of hESCs.

Biochimica Et Biophysica Acta-reviews on Cancer, 2003

The Wnt signaling pathway, named for its most upstream ligands, the Wnts, is involved in various ... more The Wnt signaling pathway, named for its most upstream ligands, the Wnts, is involved in various differentiation events during embryonic development and leads to tumor formation when aberrantly activated. Molecular studies have pinpointed activating mutations of the Wnt signaling pathway as the cause of approximately 90% of colorectal cancer (CRC), and somewhat less frequently in cancers at other sites, such as hepatocellular carcinoma (HCC). Ironically, Wnts themselves are only rarely involved in the activation of the pathway during carcinogenesis. Mutations mimicking Wnt stimulation-generally inactivating APC mutations or activating h-catenin mutations-result in nuclear accumulation of h-catenin which subsequently complexes with T-cell factor/lymphoid enhancing factor (TCF/LEF) transcription factors to activate gene transcription. Recent data identifying target genes has revealed a genetic program regulated by h-catenin/TCF controlling the transcription of a suite of genes promoting cellular proliferation and repressing differentiation during embryogenesis, carcinogenesis, and in the post-embryonic regulation of cell positioning in the intestinal crypts. This review considers the spectra of tumors arising from active Wnt signaling and attempts to place perspective on recent data that begin to elucidate the mechanisms prompting uncontrolled cell growth following induction of Wnt signaling. D

Nature, 2007

Nuclear transplantation can reprogramme a somatic genome back into an embryonic epigenetic state,... more Nuclear transplantation can reprogramme a somatic genome back into an embryonic epigenetic state, and the reprogrammed nucleus can create a cloned animal or produce pluripotent embryonic stem cells. One potential use of the nuclear cloning approach is the derivation of 'customized' embryonic stem (ES) cells for patient-specific cell treatment, but technical and ethical considerations impede the therapeutic application of this technology. Reprogramming of fibroblasts to a pluripotent state can be induced in vitro through ectopic expression of the four transcription factors Oct4 (also called Oct3/ 4 or Pou5f1), Sox2, c-Myc and Klf4. Here we show that DNA methylation, gene expression and chromatin state of such induced reprogrammed stem cells are similar to those of ES cells. Notably, the cells-derived from mouse fibroblasts-can form viable chimaeras, can contribute to the germ line and can generate live late-term embryos when injected into tetraploid blastocysts. Our results show that the biological potency and epigenetic state of in-vitro-reprogrammed induced pluripotent stem cells are indistinguishable from those of ES cells.

Probabilit?es et potentiel

Les Variables Re'gionalise'es et leur Estimation

Evolutionary Computation, 2003

This paper presents a novel evolutionary optimization strategy based on the derandomized evolutio... more This paper presents a novel evolutionary optimization strategy based on the derandomized evolution strategy with covariance matrix adaptation (CMA-ES). This new approach is intended to reduce the number of generations required for convergence to the optimum. Reducing the number of generations, i.e., the time complexity of the algorithm, is important if a large population size is desired: (1) to reduce the effect of noise;

ES&T Special Report: Priority pollutants: Ia perspective view

Environmental Science & Technology, 1979

One objective of this article is to relate the historical origins of EPA's Priority ... more One objective of this article is to relate the historical origins of EPA's Priority Pollutants and the develop-ment of the “Priority Pollutant Pro-tocol.” Most people are unaware of the difficulties involved in providing methods for the necessary analytical support for these pollutants. A ...

Es-tablishing homologies in protein sequences

... Copyright © 2011 Elsevier BV All rights reserved. SciVerse® is a registered trademark of Else... more ... Copyright © 2011 Elsevier BV All rights reserved. SciVerse® is a registered trademark of Elsevier Properties SA, used under license. ScienceDirect® is a registered trademark of Elsevier BV.

Sur le point pour lequel la somme des distances de n points donn~es est minimum

Arthritis and Rheumatism, 1994

Generating green fluorescent mice by germline transmission of green fluorescent ES cells

Mechanisms of Development, 1998

Green fluorescent protein (GFP) and its variants currently represent the only non-invasive marker... more Green fluorescent protein (GFP) and its variants currently represent the only non-invasive markers available for labeling mammalian cells in culture or in a multicellular organism through transgenesis. To date this marker gene has been widely used in the study of many organisms, but as yet has not found large-scale application in mammals due to problems encountered with weak fluorescence and instability of the wild-type protein at higher temperatures. Recently, though, several mutants have been made in the wild-type (wt) GFP so as to improve its thermostability and fluorescence. EGFP (enhanced GFP) is one such wtGFP variant. As a first step in assessing the use of EGFP in ES cell-mediated strategies, we have established a mouse embryonic stem (ES) cell lines expressing EGFP, which can be propagated in culture, reintroduced into mice. or induced to differentiate in vitro, while still maintaining ubiquitous EGFP expression. From the results presented we can suggest that: 1) possible improvements in the efficiency of transgenic regimes requiring the germline transmission of ES cells by aggregation chimeras can be made by the preselection chimeric embryos at the blastocyst stage: (2) the expression of a noninvasive marker, driven by a promoter that is active during early postimplantation development, allows access to embryos during a window of embryonic development that has previously been difficult to investigate (3) the behavior of mutant ES cells can be followed with simple microscopic observation of chimeric embryos or adult animals comprising green fluorescent cells/tissues. and (4) intercrosses of F1 mice and subsequent generations of animals show that progeny can be genotyped by UV light, such that mice homozygous for the transgene can be distinguished from hemizygotes due to their increased fluorescence.

Les In?egalit?es ? Economiques

On the Variances of Asympototically Normal Es-timators From Complex Surveys