293 research outputs found
The randomly driven Ising ferromagnet, Part II: One and two dimensions
We consider the behavior of an Ising ferromagnet obeying the Glauber dynamics
under the influence of a fast switching, random external field. In Part I, we
introduced a general formalism for describing such systems and presented the
mean field theory. In this article we derive results for the one dimensional
case, which can be only partially solved. Monte Carlo simulations performed on
a square lattice indicate that the main features of the mean field theory
survive the presence of strong fluctuations.Comment: 10 pages in REVTeX/LaTeX format, 17 eps/ps figures. Submitted to
Journal of Physics
Der Erste Weltkrieg als deutsch-französischer Erinnerungsort?
Im Mittelpunkt dieses Beitrages steht eine Analyse des Erinnerungsortes âErster Weltkriegâ und seiner Bedeutung in den deutsch-französischen Beziehungen. Dabei sollen zunĂ€chst einige grundlegende konzeptionelle Fragen geklĂ€rt werden zum Begriff âErinnerungsortâ, zu seiner Ăbertragbarkeit auf die bi- bzw. multinationale Ebene und zu seinem Zusammenhang mit dem Bereich der âGeschichtspolitikâ. Der zweite Teil skizziert die âKonjunkturenâ der Erinnerung an den Ersten Weltkrieg in Deutschland und Frankreich und unterscheidet dabei drei ZeitrĂ€ume: eine erste Phase von 1914/18 bis 1961/62, eine zweite Phase von 1961/62 bis 1989/91 und eine dritte Phase von 1989/91 bis heute. Der letzte Teil greift aus der âErinnerungslandschaftâ des Ersten Weltkriegs drei konkrete Beispiele heraus und fragt nach ihrer TragfĂ€higkeit als deutsch-französische Erinnerungsorte: â1914â, âVerdunâ und âVersaillesâ.Cet article offre une analyse de la Grande Guerre en tant que lieu de mĂ©moire franco-allemande. La premiĂšre partie prĂ©sentera le cadre conceptionnel de cette analyse, en prĂ©cisant la notion de « lieu de mĂ©moire » (« Erinnerungsort »), en exposant les possibilitĂ©s de lâadapter Ă lâĂ©chelle bi- voire plurinationale et en expliquant son rapport avec le domaine de la « politique de la mĂ©moire » (« Geschichtspolitik »). La deuxiĂšme partie esquissera les « conjonctures » de mĂ©moire de la Grande Guerre en France et en Allemagne, en distinguant trois pĂ©riodes : une premiĂšre phase de 1914/18 Ă 1961/62, une deuxiĂšme phase de 1961/62 Ă 1989/91 et une troisiĂšme phase de 1989/91 jusquâĂ nos jours. La derniĂšre partie analysera trois exemples concrets, qui font partie de ce « paysage de mĂ©moire » franco-allemand de la Grande Guerre : « 1914 », « Verdun » et « Versailles ».This contribution analyses the First World War as a Franco-German ârealm of memoryâ. The first part presents the conceptual framework of the analysis, defining the notion of ârealm of memoryâ (âlieu de mĂ©moireâ/âErinnerungsortâ), elaborating the possibility of applying this notion to a bi- or multinational context and asserting its links with what has been called the âpolitics of memoryâ (âGeschichtspolitikâ). The second part outlines the âconjuncturesâ of memory relating to the First World War in Germany and France, distinguishing three periods: 1914/18 to 1961/62, 1961/62 to 1989/91, and 1989/91 to this day. The third part attempts to evaluate the Franco-German dimension of three concrete examples taken from the âlandscape of memoryâ related to the First World War: â1914â, âVerdunâ, and âVersaillesâ
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Inhibition of Oncogenic Wnt Signaling through Direct Targeting of ÎČ-Catenin
Aberrant activation of signaling by the Wnt pathway is strongly implicated in the onset and progression of numerous types of cancer. Owing to the persistent dependence of these tumors on Wnt signaling for growth and survival, inhibition of this pathway is considered an attractive mechanism-based therapeutic approach. Oncogenic activation of Wnt signaling can ensue from a variety of distinct aberrations in the signaling pathway, but most share the common feature of causing increased cellular levels of ÎČ-catenin by interfering with its constitutive degradation. ÎČ-Catenin serves as a central hub in Wnt signaling by engaging in crucial proteinâprotein interactions with both negative and positive effectors of the pathway. Direct interference with these proteinâprotein interactions is a biologically compelling approach toward suppression of ÎČ-catenin hyperactivity, but such interactions have proven intransigent with respect to small-molecule targeting. Hence ÎČ-catenin remains an elusive target for translational cancer therapy. Here we report the discovery of a hydrocarbon-stapled peptide that directly targets ÎČ-catenin and interferes with its ability to serve as a transcriptional coactivator for T-cell factor (TCF) proteins, the downstream transcriptional regulators of the Wnt pathway.Chemistry and Chemical BiologyStem Cell and Regenerative Biolog
The randomly driven Ising ferromagnet, Part I: General formalism and mean field theory
We consider the behavior of an Ising ferromagnet obeying the Glauber dynamics
under the influence of a fast switching, random external field. After
introducing a general formalism for describing such systems, we consider here
the mean-field theory. A novel type of first order phase transition related to
spontaneous symmetry breaking and dynamic freezing is found. The
non-equilibrium stationary state has a complex structure, which changes as a
function of parameters from a singular-continuous distribution with Euclidean
or fractal support to an absolutely continuous one.Comment: 12 pages REVTeX/LaTeX format, 12 eps/ps figures. Submitted to Journal
of Physics
De novo expression of gastrokines in pancreatic precursor lesions impede the development of pancreatic cancer
Molecular events occurring in stepwise progression from pre-malignant lesions (pancreatic intraepithelial neoplasia; PanIN) to the development of pancreatic ductal adenocarcinoma (PDAC) are poorly understood. Thus, characterization of early PanIN lesions may reveal markers that can help in diagnosing PDAC at an early stage and allow understanding the pathology of the disease. We performed the molecular and histological assessment of patient-derived PanINs, tumor tissues and pancreas from mouse models with PDAC (KC mice that harbor K-RAS mutation in pancreatic tissue), where we noted marked upregulation of gastrokine (GKN) proteins. To further understand the role of gastrokine proteins in PDAC development, GKN-deficient KC mice were developed by intercrossing gastrokine-deficient mice with KC mice. Panc-02 (pancreatic cancer cells of mouse origin) were genetically modified to express GKN1 for further in vitro and in vivo analysis. Our results show that gastrokine proteins were absent in healthy pancreas and invasive cancer, while its expression was prominent in low-grade PanINs. We could detect these proteins in pancreatic juice and serum of KC mice. Furthermore, accelerated PanIN and tumor development were noted in gastrokine deficient KC mice. Loss of gastrokine 1 protein delayed apoptosis during carcinogenesis leading to the development of desmoplastic stroma while loss of gastrokine 2 increased the proliferation rate in precursor lesions. In summary, we identified gastrokine proteins in early pancreatic precursor lesions, where gastrokine proteins delay pancreatic carcinogenesis
The strengths and limitations of routine staging before treatment with abdominal CT in colorectal cancer
<p>Abstract</p> <p>Background</p> <p>Advanced colorectal cancer (CRC), either locally advanced, metastasized (mCRC) or both, is present in a relevant proportion of patients. The chances on curation of advanced CRC are continuously improving with modern multi-modality treatment options. For incurable CRC the focus lies on palliation of symptoms, which is not necessarily a resection of the primary tumor. Both situations motivate adequate staging before treatment in CRC. This prospective observational study evaluates the outcomes after the introduction of routine staging with abdominal CT before treatment.</p> <p>Methods</p> <p>In a prospective observational study of 612 consecutive patients (2007-2009), the ability of abdominal CT to find liver metastases (LM), peritoneal carcinomatosis (PC) and T4 stage in colon cancer (CC) was analysed.</p> <p>Results</p> <p>Advanced CRC was present in 58% of patients, mCRC in 31%. The ability to find LM was excellent (99%), cT4 stage CC good (86%) and PC poor (33%). In the group of surgical patients with emergency presentations, the incidences of both mCRC (51%) and locally advanced colon cancer (LACC) (69%) were higher than in the elective group (20% and 26% respectively). Staging tended to be omitted more often in the emergency group (35% versus 12% in elective surgery).</p> <p>Conclusions</p> <p>The strengths of staging with abdominal CT are to find LM and LACC, however it fails in diagnosing PC. On grounds of the incidence of advanced CRC, staging is warranted in patients with emergency presentations as well.</p
Separable functions of wingless in distal and ventral patterning of the Tribolium leg
The gene wingless (wg) in Drosophila is an important factor in leg development. During embryonic development wg is involved in the allocation of the limb primordia. During imaginal disk development wg is involved in distal development and it has a separate role in ventral development. The expression pattern of wg is highly conserved in all arthropods (comprising data from insects, myriapods, crustaceans, and chelicerates), suggesting that its function in leg development is also conserved. However, recent work in other insects (e.g. the milkweed bug Oncopeltus fasciatus) argued against a role of wg in leg development. We have studied the role of wg in leg development of the flour beetle Tribolium castaneum. Using stage-specific staggered embryonic RNAi in wild-type and transgenic EGFP expressing enhancer trap lines we are able to demonstrate separable functions of Tribolium wg in distal and in ventral leg development. The distal role affects all podomeres distal to the coxa, whereas the ventral role is restricted to cells along the ventral midline of the legs. In addition, severe leg defects after injection into early embryonic stages are evidence that wg is also involved in proximal development and limb allocation in Tribolium. Our data suggest that the roles of wg in leg development are highly conserved in the holometabolous insects. Further studies will reveal the degree of conservation in other arthropod groups
Family Matters:Rethinking the Psychology of Human Social Motivation
What motives do people prioritize in their social lives? Historically, social psychologists, especially those adopting an evolutionary perspective, have devoted a great deal of research attention to sexual attraction and romantic-partner choice (mate seeking). Research on long-term familial bonds (mate retention and kin care) has been less thoroughly connected to relevant comparative and evolutionary work on other species, and in the case of kin care, these bonds have been less well researched. Examining varied sources of data from 27 societies around the world, we found that people generally view familial motives as primary in importance and mate-seeking motives as relatively low in importance. Compared with other groups, college students, single people, and men place relatively higher emphasis on mate seeking, but even those samples rated kin-care motives as more important. Furthermore, motives linked to long-term familial bonds are positively associated with psychological well-being, but mate-seeking motives are associated with anxiety and depression. We address theoretical and empirical reasons why there has been extensive research on mate seeking and why people prioritize goals related to long-term familial bonds over mating goals. Reallocating relatively greater research effort toward long-term familial relationships would likely yield many interesting new findings relevant to everyday peopleâs highest social priorities
Fundamental social motives measured across forty-two cultures in two waves
How does psychology vary across human societies? The fundamental social motives framework adopts an evolutionary approach to capture the broad range of human social goals within a taxonomy of ancestrally recurring threats and opportunities. These motivesâself-protection, disease avoidance, affiliation, status, mate acquisition, mate retention, and kin careâare high in fitness relevance and everyday salience, yet understudied cross-culturally. Here, we gathered data on these motives in 42 countries (N = 15,915) in two cross-sectional waves, including 19 countries (N = 10,907) for which datawere gathered in both waves. Wave 1 was collected from mid-2016 through late 2019 (32 countries, N = 8,998; 3,302 male, 5,585 female; Mage = 24.43, SD = 7.91). Wave 2 was collected from April through
November 2020, during the COVID-19 pandemic (29 countries, N = 6,917; 2,249 male, 4,218 female; Mage = 28.59, SD = 11.31). These data can be used to assess differences and similarities in peopleâs fundamental social motives both across and within cultures, at different time points, and in relation to other commonly studied cultural indicators and outcomes
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