In making decisions regardmg what to do, people should employ plausible moral standards to defend what they think is morally permissible. One plausible moral standard that is often used is what I refer to as the Rational Person Standard: we, as rational agents, ought to choose the option that has the greatest benefit for us, under the constraint that what we choose does not unfairly limit other people from choosing what they think is best for them. Another way to phrase (...) this standard is: rational agents will not choose an action that will cause uimecessary and avoidable harm. In this paper I will apply this standard to an analysis of a systemic issue common to many moral problems, using sweatshops as an example, that, if ignored, may lead us to make, and act upon, arguments that seem plausible in one context, but ultimately fail when considered from another context. (shrink)

In modern academic career systems there are a large number of entry positions, much smaller numbers of intermediate positions, and still fewer full professorships. We examine how this system has developed in Germany, the country where the modern academic system was introduced, tracing the historical development of academic positions since the early 19th century. We show both a differentiation and professionalization. At first, professorships and private lecturer positions were the only formal positions, but later, lower formal academic positions emerged. (...) Over the whole period, the share of higher academic positions steadily decreased. This differentiation process was closely connected to professionalization: remuneration through salaries was extended from professors to almost everyone working in the German academic system. We propose that the process of differentiation and professionalization was induced by the expansion and democratization of higher education. Finally, our study shows that the opportunities for PhDs to obtain salaried doctoral positions have increased since the 1950s. On the other hand, opportunities for PhDs to become a professor or obtain another tenured job have decreased since the 1980s due to a slowdown of higher education expansion. (shrink)

ABSTRACTPrevious research has found that individuals vary greatly in emotion differentiation, that is, the extent to which they distinguish between different emotions when reporting on their own fe...

Musical flutes constructed from bird bone and mammoth ivory begin to appear in the archaeological record from around 40,000 years ago. Due to the different physical demands of acquiring and working with these source materials in order to produce a flute, researchers have speculated about the significance—aesthetic or otherwise—of the use of mammoth ivory as a raw material for flutes. I argue that biological signaling theory provides a theoretical basis for the proposition that mammoth ivory flute production is a signal (...) of increasing social differentiation in Upper Palaeolithic human life. (shrink)

Indirect routes by which gonadal hormones influence sexual differentiation are considered. In rats, differentiation may depend on the way in which the mother responds to the hormonal condition of her pups, and this has implications for the interpretation of the data for humans. Interaction between gonadal hormones and light experience in chicks is compared with the mammalian systems covered in Fitch & Denenberg's review.

The ascidian embryo has long provided a model system for ‘mosaic’ development. This article reviews recent advances in the study of ascidian developmental biology. These include: (a) the re‐analysis of cell lineages in ascidian embryos with the ascertainment of developmental fates of every blastomere of a 110‐cell embryo; (b) the development of several tissue‐specific monoclonal antibodies; (c) the investigation and description of cell cycle requirements for differentiation; it has been found that neither cytokinesis nor nuclear division is required for (...) differentiation, but that several rounds of DNA replication are essential for the expression of certain tissue‐specific genes; and (d) the demonstration by new descriptive and experimental studies of the presence of cytoplasmic factors or determinants responsible for specification of embryonic cell features; myoplasm which is thought to contain muscle determinants has been isolated, and immunological attempts to elucidate the molecular nature of the factors have begun. (shrink)

Individuals differ considerably in their emotion experience. Some experience emotions in a highly differentiated manner, clearly distinguishing among a variety of negative and positive discrete emotions. Others experience emotions in a relatively undifferentiated manner, treating a range of like-valence terms as interchangeable. Drawing on self-regulation theory, we hypothesised that individuals with highly differentiated emotion experience should be better able to regulate emotions than individuals with poorly differentiated emotion experience. In particular, we hypothesised that emotion differentiation and emotion regulation would (...) be positively related in the context of intense negative emotions, where the press for emotion regulation is generally greatest. To test this hypothesis, participants' negative and positive emotion differentiation was assessed using a 14-day diary protocol. Participants' regulation of negative and positive emotions was assessed using laboratory measures. As predicted, negative emotion differentiation was positively related to the frequency of negative emotion regulation, particularly at higher levels of emotional intensity. (shrink)

On the basis of the evidence that tumor development is suppressed by the embryonic microenvironment, some experiments using the factors taken from Zebrafish embryo at precise stages of cell differentiation were made. These experiments demonstrated a significant growth inhibition on different tumor cell lines in vitro. The observed mechanism of tumor growth inhibition is connected with the key-role cell cycle regulation molecules, such as p53 and pRb, which are modified by transcriptional or post-translational processes. Research on apoptosis and (...) class='Hi'>differentiation revealed that treatment with these factors induces caspase-3 with a p73 apoptotic-dependent pathway activation and a concurrent significant normalization of e-cadherin and beta-catenin ratio. Other experiments found a synergistic effect on the colon cancer proliferation curve after the concurrent treatment with these factors and 5-fluorouracil. Finally, a product prepared for human therapy demonstrated 19.8% regression and 16% stable disease in an... (shrink)

The “community effect” is necessary for tissue differentiation. In the Xenopus muscle paradigm, e‐FGF has been identified as a candidate community factor. Standley et al.1 now show that the community effect, mediated through FGF signalling, continues to be important at later stages of development in the posterior part of the embryo. In this region, the paraxial mesoderm is still undergoing segmentation into somites, which are the site of early skeletal muscle formation. Indeed, somitogenesis, together with the read‐out of the (...) Hox code, which confers anteroposterior positional identity, is regulated by FGF signalling. This raises the question of the co‐ordination between these events and the community effect which orchestrates myogenesis. BioEssays 25:13–16, 2003. © 2002 Wiley Periodicals, Inc. (shrink)

In Primitive Classification, Durkheim suggests using the notion of affectivity to explain the emergence of various social structures. This bold attempt to extend the role of affectivity in sociological thinking has been rejected by most social scientists. By greatly elaborating Durkheim's outline for a sociology of emotions, however, this essay suggests that there is a fruitful way to use affectivity in macrosociological theory. This model allows us to develop in a new way Durkheim's description of structural differentiation and stratification (...) in The Division of Labor in Society. (shrink)

A model is given of the development of a radialised larval head pattern inLimnaea stagnalis, as it occurs under certain experimental conditions. It is assumed that the differentiation of the pattern is entirely based on cell-internal factors, and that the internal state of each cell is dependent on that of its progenitor and on the direction of the division by which it is produced. This internal state determines the direction of the subsequent division or the nature of the cell's (...) differentiation. Cell interactions, which are during this period of minor importance, are left out of consideration. (shrink)

Recent work by Magnuson, Solomon and Grossman(1) adds to a growing body of evidence indicating that microorganisms possess sophisticated signaling systems that enable them to sense and respond to environmental challenges. Typically, this response results in morphological, physiological and even genetic differentiation, paralleling that observed among higher organisms. These signaling systems may be interpreted as adaptations that maximize the reproductive potential of a population.

On the basis of research in the social identity tradition, we contend (a) that identification and differentiation are not mutually exclusive, (b) that a sequence in which identification gives way to differentiation is not necessarily associated with superior organizational outcomes, and (c) that social identification, and leadership that builds this, is generally a prerequisite for group success.

Recently it has become clear that integrins and other adhesive receptors play an important role in the control of cell growth and differentiation. In various cell types, anchorage to the extracellular matrix via integrins strongly influences the ability of the cell to respond to soluble mitogens or to differentiation factors. Thus adhesive receptors must generate signals that influence cell behavior. Some of the pathways of adhesion receptor signaling are now beginning to be worked out, but there is still (...) much to learn. In particular, the mechanistic basis for the cooperation between anchorage signals and signals from soluble growth and differentiation factors remains ill‐defined. This review will examine some of the current information linking adhesion receptors to control of mitogenesis and differentiation. (shrink)

Ideas of ‘distributed mind’ are invaluable to archaeology in explaining the intimate involvement of artefacts in human cognition. Much of the work in this domain, however, focuses on proximate interactions of very limited numbers of individuals and artefacts. This chapter argues that people need to broaden the understanding of distributed mind to encompass whole assemblages of artefacts spread across space and time; and that these assemblages can be best conceptualized as networks in which both objects and people are enfolded and (...) enacted. While such networks may exist to some extent in the Palaeolithic and Neolithic eras, it is with the Bronze Age that they really come to the fore, extending the scale of human action beyond the proximate like never before. Examples of this extensive socio-material differentiation are taken from the Aegean Bronze Age, with a focus on pottery. (shrink)

This review explores the hypothesis that regulation of nucleocytoplasmic shuttling is a means of driving differentiation, using spermatogenesis as a model. The transition from undifferentiated spermatogonial stem cell to terminally differentiated spermatozoon is, at its most basic, a change in the repertoire of expressed genes. To effect this, the complement of nuclear proteins, such as transcription factors and chromatin remodelling components must change. Current knowledge of the nuclear proteins and nucleocytoplasmic transport machinery relevant to spermatogenesis is consolidated in this (...) review, and their functional linkages are highlighted not only as a means of regulating nuclear protein composition, but also as a key mechanism regulating gene transcription and hence cell fate. Through this, we hypothesize that male germ cell differentiation is mediated through regulation of nuclear transport machinery components, and thereby of the access of critical factors to the nucleus. The importance of nucleocytoplasmic trafficking to male germ cell differentiation is discussed, using the sex-determining factors Sry and SOX9, cell cycle regulators, CREM and cofactors and the Smads as specific examples, together with the roles in gametogenesis for particular nuclear transport factors in Caenorhabditis elegans and Drosophila. BioEssays 27:1011–1025, 2005. © 2005 Wiley Periodicals, Inc. (shrink)

Construction of the trunk/caudal region of the vertebrate embryo involves a set of distinct molecules and processes whose relationships are just coming into focus. In addition to the subdivision of the embryo into head and trunk domains, this “caudalisation” process requires the establishment and maintenance of a stem zone. This sequentially generates caudal tissues over a long period which then undergo differentiation and patterning in the extending body axis. Here we review recent studies that show that changes in the (...) signalling properties of the paraxial mesoderm act as a switch that controls onset of differentiation and pattern in the spinal cord. These findings identify distinct roles for different caudalising factors; in particular, Fibroblast Growth Factor (FGF) inhibits differentiation in the caudal stem zone, while Retinoic acid (RA) provided rostrally by somitic mesoderm is required for neuronal differentiation and establishment of ventral neural pattern. Furthermore, the mutual opposition of FGF and RA pathways controls not only neural differentiation but also mesoderm segmentation and might also underlie the progressive assignment of rostrocaudal identity by regulating Hox gene availability and activation. BioEssays 26:857–869, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

The development of factor markets has opened Chinese agriculture for the penetration of capitalism. This new round of rural transformation—China’s agrarian transition— raises the agrarian question in the Chinese context. This study investigates how capitalist forms and relations of production transform agricultural production and the peasantry class in rural China. The authors identify six forms of nonpeasant agricultural production, compare the labor regimes and direct producers’ socioeconomic statuses across these forms, and evaluate the role of China’s land-rights institution in shaping (...) these forms. The empirical investigation presents three main findings: Peasant differentiation : capitalist forms of agricultural production differentiate peasants into a variety of new class positions. Market-based stratification: producers in capitalist agriculture are primarily stratified by their positions in labor and land markets; their socioeconomic statuses are linked with their varying degrees of proletarianization. Institutional mediation: rural China’s dual-track land system plays a crucial role in shaping the diverse and unique forms of capitalist production. (shrink)

The differentiation of T Lymphocytes within the thymus is an important biological phenomenon during wich these cell acquire their functions to further control the immune system. Numerous experiments under various conditions have been devised to understand the different mechanisms involved in this complex process. Nevertheless, interpretation of these experiments lead to still contradictory debatable hypotheses. Modelisation of this process through classical simulation methods cannot be envisaged because they are not adapted to modifications of the model structure, which is the (...) point of interest. For these reasons, we proposed a new approach of automatic search for model. The program consists of four independent connected modules : The generator produces model, based on the rationale of formal grammars. Protocol and experimental data are stored in a set of experiments. The simulator using a protocol and a model provides simulated results. Finally, the supervisor by comparing simulated results and experimental data, adapts the model parameters to increase their fit and either chooses a new experiment to explore, or modifies the model structure. Change of the model structure is performed among still unexplored models according to their promise level, which is iteratively evaluated relatively to previously explored models through a proposed model distance. The generator is written in Prolog and the other modules in C++. The architecture of the program allows us to modify or complete a module without changing anything in the other modules. As a consequence, the proposed modeling approach conceived to study T lymphocyte differentiation within the thymus remains independent of this biological phenomenon and can be applied to other biological problems. (shrink)

The neural crest is a transient population of multipotent progenitors arising at the lateral edge of the neural plate in vertebrate embryos. After delamination and migration from the neuroepithelium, these cells contribute to a diverse array of tissues including neurons, smooth muscle, craniofacial cartilage, bone cells, endocrine cells and pigment cells. Considerable progress in recent years has furthered our understanding at a molecular level of how this important group of cells is generated and how they are assigned to specific lineages. (...) Here we review a number of recent studies supporting a role for Wnt signaling in neural crest induction, differentiation, and apoptosis. We also summarize the timing of expression of a number of Wnt ligands and receptors with respect to neural crest induction. BioEssays 25:317–325, 2003. © 2003 Wiley Periodicals, Inc. (shrink)

Nineteenth-century scientist Hermann von Helmholtz’s peculiar wavering between empiricism and transcendentalism in his philosophy of science in general, and in his theory of perception in particular, is a much debated and well-documented topic in the history and philosophy of science. This contribution aims at providing a fresh angle on this classical issue, by considering Helmholtz’s account of differential consciousness against the background of a centuries-old philosophical debate between the empiricist tradition and the tradition of transcendental idealism. By placing Helmholtz’s psychology (...) against the background of a historical narrative stretching from Hume to Fichte, one can gain insight into the possible merits of his empirico-transcendentalism with regard to the problem of differentiation. More particularly, it is argued that Helmholtz’s psychology tilted towards transcendentalism when met with the classical theoretical problems of strict empiricism in dealing with the foundation of consciousness, most notably circularity and infinite regress. Without claiming that Helmholtz’s theorizing presented a self-conscious attempt to overcome the latter issues, his well-known wavering between perspectives in general, and his appropriation of the a priori in particular, might have served him well in avoiding the deadlocks of empiricism. As noted at the end, however, Helmholtz’s account produced complex philosophical problems of its own. (shrink)

Hepatocellular carcinoma represents the third leading cause of cancer-related death. Because HCC is multicentric with time, excluding the few transplanted patients, sooner or later it becomes untreatable with loco-regional therapies and, until some years ago, it was not responsive to systemic therapies. In 2005 a randomized trial indicated the efficacy of a product containing stem cell differentiation stage factors taken from zebrafish embryos during the stage in which the totipotent stem cells are differentiating into the pluripotent adult stem cells. (...) In such a trial the patients, with “intermediate” and “advanced” HCC according to Barcelona Clinic Liver Cancer/American Association for the Study of Liver Diseases guidelines, presented benefit in terms of performance status and objective tumoral response, with some cases of complete response, that is, sustained disappearance of the neoplastic areas or blood supply therein, accompanied by normalization of alpha-fetoprotein... (shrink)

For over a century, Haeckel's Gastraea theory remained a dominant theory to explain the origin of multicellular animals. According to this theory, the animal ancestor was a blastula‐like colony of uniform cells that gradually evolved cell differentiation. Today, however, genes that typically control metazoan development, cell differentiation, cell‐to‐cell adhesion, and cell‐to‐matrix adhesion are found in various unicellular relatives of the Metazoa, which suggests the origin of the genetic programs of cell differentiation and adhesion in the root of (...) the Opisthokonta. Multicellular stages occurring in the complex life cycles of opisthokont protists (mesomycetozoeans and choanoflagellates) never resemble a blastula. Here, we discuss a more realistic scenario of transition to multicellularity through integration of pre‐existing transient cell types into the body of an early metazoon, which possessed a complex life cycle with a differentiated sedentary filter‐feeding trophic stage and a non‐feeding blastula‐like larva, the synzoospore. Choanoflagellates are considered as forms with secondarily simplified life cycles. (shrink)

The interrelationships among recent theories on the regulation of gene activity and differentiation in higher organisms are reviewed. Interpretations within these theories of the various components of chromosomes are re-evaluated and a unified conceptual framework of hierarchical genetic control mechanisms in eukaryotes is presented.

The current major models of coexistence of species on the same resources are briefly summarized. It is then shown that analysis of supposedly competitive systems in terms of the physical four dimensions of phase-space is sufficient to understand the causes for coexistence and for competitive exclusion. Thus, the multiple dimensions of niche theory are reduced to factors which define the magnitudes of the phase-spatial system, in particular the boundaries of population spaces and of periods of activity. Excluding possible cooperative interaction (...) between consumers, it appears that coexistence of species on thesame kind of limiting resource is possible only in cases of compartmentalization either in space, or in time, of resource consumption, i.e. if each consumer species disposes of a separate resource supply. Three criteria were found to be decisive for successful compartmentalization (i.e. for coexistence): 1. the vector of the resource flow; 2. relative mobility between consumers and resource units; 3. dependence or independence of resource flow on previous consumption. The traditional terminology of niche theory and of competition theory in general proved to be inadequate for analytical treatment of problems of coexistence. (shrink)

Multiple Sclerosis is a debilitating chronic autoimmune disease of the central nervous system that results in lower quality of life. Medication adherence is important for reducing relapse, disease progression, and MS-related symptoms, particularly during the early stages of MS. However, adherence may be impacted by negative emotional states. Therefore, it is important to identify protective factors. Past research suggests that the ability to discriminate between negative emotional states, also known as negative emotion differentiation, may be protective against enactment of (...) maladaptive risk-related behaviors. However, less is known as to how NED may promote adaptive health behaviors such as medication adherence. Utilizing weekly diaries, we investigated whether NED moderates the association between negative affect and medication adherence rates across 58 weeks among patients newly diagnosed with MS. Results revealed that NED significantly moderated the relationship between negative affect and medication adherence. Specifically, greater negative affect was associated with lower adherence only for individuals reporting low NED. However, this link disappeared for those reporting moderate to high NED. Building upon past research, our findings suggest that NED may promote adaptive health behaviors and have important clinical implications for the treatment and management of chronic illness. (shrink)

In the early 1950s, the Chinese communist party promoted a massive Learning-from-the-Soviet-Union Campaign and made Pavlov’s reflexology the political-academic orthodoxy in physiology, medical science and psychology. In the late 1950s, however, while Pavlov’s theory was continuously advocated by physiologists and medical scientists, it suffered a major setback in psychology as Pavlovian psychology was criticized as being bourgeois and reactionary. How was it possible for such sheer contrast across disciplines to take place within a few years? This paper argues that the (...) greater ideologization of Pavlovian psychology was conditioned by a number of factors: the Sino-Soviet relations, the shifting Chinese communist policies, professional practices, local social conditions, disciplinary cultures and discursive performances. This historical reconstruction rejects a homogenizing view of the relation between politics and science in the Maoist China, and demonstrates ways in which historical localities and dynamics ruptured the overarching political context. (shrink)

The stable differentiation of cells into other cell types typically involves dramatic reorganization of cellular structures and functions. This often includes remodeling of the cell cycle and the apparatus that controls it. Here we review our understanding of the role and regulation of cell cycle control elements during cell differentiation in the yeast, Saccharomyces cerevisiae. Although the process of differentiation may be more overtly obvious in metazoan organisms, those systems are by nature more difficult to study at (...) a mechanistic level. We consider the relatively well‐understood mechanisms by which mating‐type switching and the pheromone‐induced differentiation of gametes are coupled to the cell cycle as well as the more obscure mechanisms that govern the remodeling of the cell cycle during meiosis and filamentous growth. In some cases, the cell cycle is a primary stimulus for differentiation whereas, in other cases, the signals that promote differentiation alter the cell cycle. Thus, despite relative simplicity of these processes in yeast, the nature of the interplay between the cell cycle and differentiation is diverse. BioEssays 25:856–867, 2003. © 2003 Wiley Periodicals, Inc. (shrink)

The mature cerebral cortex contains a staggering variety of projection neuron subtypes, and a number of complementary studies have recently begun to define their identity and embryonic origin. Among the different types of cortical projection neurons, subcerebral projection neurons, including corticospinal motor neurons (CSMN), have been extensively studied and some of the molecular controls over their differentiation have been elucidated. Here, we first provide an overview of the approaches used to purify and molecularly profile neuronal populations of the neocortex (...) and, more broadly, of the central nervous system (CNS). Next, we specifically review recent progress in understanding the genes that define and control development of the CSMN population. Finally, we briefly discuss the relevance of this work to current questions regarding the mechanisms of the establishment of projection neuron subtype identity in the neocortex and its implications to direct the differentiation of CSMN for therapeutic benefit. (shrink)