julilili42/papers huggingface dataset:
Book reviews - Tobias L. Kienlin. Traditions and transformations: approaches to Eneolithic (Copper Age) and Bronze Age metalworking and society in Eastern Central Europe and the Carpathian Basin (British Archaeological Reports International Series 2184). iv+406 pages, 302 illustrations, CD. 2011. Oxford: Archaeopress; 978-1-4073-0740-4 paperback £61.
2011-11-01

Book reviews - Tobias L. Kienlin. Traditions and transformations: approaches to Eneolithic (Copper Age) and Bronze Age metalworking and society in Eastern Central Europe and the Carpathian Basin (British Archaeological Reports International Series 2184). iv+406 pages, 302 illustrations, CD. 2011. Oxford: Archaeopress; 978-1-4073-0740-4 paperback £61. - Volume 85 Issue 330
Limit order books and trade informativeness
2011-11-02

In the microstructure literature, information asymmetry is an important determinant of market liquidity. The classic setting is that uninformed dedicated liquidity suppliers charge price concessions when incoming market orders are likely to be informationally motivated. In limit order book (LOB) markets, however, this relationship is less clear, as market participants can switch roles, and freely choose to immediately demand or patiently supply liquidity by submitting either market or limit orders. We study the importance of information asymmetry in LOBs based on a recent sample of 30 German Deutscher Aktienindex (DAX) stocks. We find that Hasbrouck's (1991) measure of trade informativeness Granger causes book liquidity, in particular that required to fill large market orders. Picking-off risk due to public news-induced volatility is more important for top-of-the book liquidity supply. In our multivariate analysis, we control for volatility, trading volume, trading intensity and order imbalance to isolate the effect of trade informativeness on book liquidity.
Collisions of inhomogeneous pre-planetesimals
2011-11-03

\\n Context. In the framework of the coagulation scenario, kilometre-sized planetesimals form by subsequent collisions of pre-planetesimals of sizes from centimetre to hundreds of metres. Pre-planetesimals are fluffy, porous dust aggregates, which are inhomogeneous owing to their collisional history. Planetesimal growth can be prevented by catastrophic disruption in pre-planetesimal collisions above the destruction velocity threshold.\\n Aims. We assess whether the inhomogeneity created by subsequent collisions has a significant influence on the stability of pre-planetesimal material to withstand catastrophic disruption. We wish to develop a model that is explicitly able to resolve any inhomogeneous structures. The input parameters of this model must be easily accessible from laboratory measurements.\\n Methods. We develop an inhomogeneity model based on the density distribution of dust aggregates, which is assumed to be a Gaussian distribution with a well-defined standard deviation. As a second input parameter, we consider the typical size of an inhomogeneous clump. For the simulation of the dust aggregates, we utilise a smoothed particle hydrodynamics (SPH) code with extensions for modelling porous solid bodies. The porosity model was previously calibrated for the simulation of SiO2 dust, which commonly serves as an analogue for pre-planetesimal material. The inhomogeneity is imposed as an initial condition on the SPH particle distribution. We carry out collisions of centimetre-sized dust aggregates of intermediate porosity. We vary the standard deviation of the inhomogeneous distribution at fixed typical clump size. The collision outcome is categorised according to the four-population model.\\n Results. We show that inhomogeneous pre-planetesimals are more prone to destruction than homogeneous aggregates. Even slight inhomogeneities can lower the threshold for catastrophic disruption. For a fixed collision velocity, the sizes of the fragments decrease with increasing inhomogeneity. \\n Conclusions. Pre-planetesimals with an active collisional history tend to be weaker. This is a possible obstacle to collisional growth and needs to be taken into account in future studies of the coagulation scenario.\\n
Convergence and divergence of numeracy: the development of age heaping in Latin America from the seventeenth to the twentieth century1
2011-11-04

This study makes the first systematic attempt to trace the long‐term development of Latin American numeracy, a phenomenon of great interest to economic historians in that it serves as an accurate gauge of human capital development. In order to approximate basic numeracy we use age‐heaping techniques. We find that Latin America was on a path of convergence with western Europe during the early eighteenth century. During the early nineteenth century, not only did numeracy development stagnate in some Latin American countries but differences among some of them actually increased. While numeracy rates in Argentina, Uruguay, and to a lesser extent Brazil, along with Europe, underwent a significant increase in the late nineteenth century, they declined in Mexico, Ecuador, and Colombia. By performing a regression analysis, we find that, even when we control for investment in education, mass immigration contributed to human capital formation.
Animal Navigation: A Synthesis
2011-11-04

Navigation, the ability to organize behavior adaptively to move from one place to another, appeared early in the evolution of animals and occurs in all mobile species. At the simplest level, navigation may require only movement toward or away from a stimulus, but at a more sophisticated level, it involves the formation of complex internal representations of the environment, the subject's position within it, the location of goals, the various routes from current position to goal and possible obstacles along the way. The vast array of navigational capabilities in various species has made it challenging for students of comparative cognition to formulate unifying frameworks to describe and understand these capabilities, although the variety also confers an exciting opportunity for asking comparative questions that are hypothesis driven. A unifying framework, the navigation toolbox, is proposed to provide a way of formulating common underlying principles that operate across many different taxa. The toolbox contains a hierarchy of representations and processes, ranging in complexity from simple and phylogenetically old sensorimotor processes, through the formation of navigational primitives such as orientation or landmark recognition, up to complex cognitive constructs such as cognitive maps, and fi nally culminating in the human capacity for symbolic representation and language. Each element in the hierarchy is positioned at a given level by virtue of being constructed from elements in the lower levels and having newly synthesized spatial semantic contents in the representations that were not present in the lower levels. In studying individual species, the challenge is to determine how given elements are implemented in that species, in view of its particular behavioral and anatomical constraints. The challenge for the fi eld as a whole is to understand the semantic structure of spatial representations in general, which ultimately entails understanding the behavioral and neural mechanisms by which semantic content is synthesized from sensory inputs, stored, and used to generate behavior. © 2011 Massachusetts Institute of Technology and the Frankfurt Institute for Advanced Studies. All rights reserved.
To Be or Not to Be a Fossil Rhodolith? Analytical Methods for Studying Fossil Rhodolith Deposits
2011-11-04

Abstract BASSI, D.; IRYU, Y., and NEBELSICK, J.H., 2012. To be or not to be a fossil rhodolith? Analytical methods for studying fossil rhodolith deposits. The past environment is often reconstructed by measuring certain proxy data, such as changes in oxygen isotopes, taxonomic assemblages, and taphonomic signatures in a palaeoenvironmental archive (e.g., rhodoliths, corals, invertebrate shells, trees, ice cores, speleothems, etc.). Proxy analysis usually yields a record that has to be compared with present-day analogues to yield meaningful results. This also holds true for the interpretation of the palaeoenvironment of rhodolith deposits. The characteristics of Recent rhodoliths and the environments in which they are formed, thus, need to be known to interpret their fossil counterparts. The comparison of fossil and Recent rhodoliths and their environment is, however, not straightforward because the respective analytical methods applied to them are usually different and often difficult to reconcile. To reduce the uncertainties of this problem and to facilitate direct comparisons, we describe a number of analytical methods applied to fossil rhodoliths that can also be performed on Recent material. The analytical methods introduced here correspond to three different scales of analysis: (1) the outcrop scale as completed in field studies and the study of (2) isolated specimens and (3) thin sections in the laboratory.
Works Councils and Flexible Collective Bargaining Agreements
2011-11-04

Based on the article by Hubler and Jirjahn (2003), I analyse the interaction effects of works councils and collective bargaining agreements (CBAs) on productivity and wages in German plants. In contrast to previous literature, newer developments in the system of industrial relations could countervail the moderating effects of collective bargaining on works council behaviour. Increased decentralisation and flexibility of collective bargaining at the plant level induced by opening clauses and company-level pacts for employment require works councils to negotiate over wages, which is usually forbidden in the Works Constitution Act. This could dampen their efforts on fostering productivity-enhancing measures. Contrary, the empirical results show that in plants with opening clauses works councils actually increase productivity by a larger magnitude compared to plants without opening clauses, while wages stay the same. However, the existence of company-level pacts for employment does not produce different works council behaviour. Our results suggest that there are no adverse effects of CBA decentralisation on works council behaviour.
Increased functional connectivity indicates the severity of cognitive impairment in multiple sclerosis
2011-11-07

Correlations in spontaneous brain activity provide powerful access to large-scale organizational principles of the CNS. However, making inferences about cognitive processes requires a detailed understanding of the link between these couplings and the structural integrity of the CNS. We studied the impact of multiple sclerosis, which leads to the severe disintegration of the central white matter, on functional connectivity patterns in spontaneous cortical activity. Using a data driven approach based on the strength of a salient pattern of cognitive pathology, we identified distinct networks that exhibit increases in functional connectivity despite the presence of strong and diffuse reductions of the central white-matter integrity. The default mode network emerged as a core target of these connectivity modulations, showing enhanced functional coupling in bilateral inferior parietal cortex, posterior cingulate, and medial prefrontal cortex. These findings imply a complex and diverging relation of anatomical and functional connectivity in early multiple sclerosis and, thus, add an important observation for understanding how cognitive abilities and CNS integrity may be reflected in the intrinsic covariance of functional signals.
Impact of phosphoproteomics on studies of bacterial physiology
2011-11-08

Protein phosphorylation on serine, threonine and tyrosine is recognized as a major tool of signal transduction in bacteria. However, progress in the field has been hampered by the lack of global and site-specific data on bacterial phosphoproteomes. Recent advances in mass spectrometry-based proteomics have encouraged bacteriologists to start using powerful gel-free approaches for global detection of phosphorylated proteins. These studies have generated large data sets of proteins phosphorylated on serine, threonine and tyrosine, with identified phosphorylation sites which represent an excellent starting point for in-depth physiological characterization of kinases and their substrates. The list of phosphorylated proteins inspired a number of physiological studies in which the identity of the phosphorylation site facilitated the elucidation of molecular mechanisms of signaling and regulation. Bacterial phosphoproteomics also provided interesting insights into the evolutionary aspects of protein phosphorylation. The field is rapidly embracing quantitative mass spectrometry strategies, comparing phosphoproteome dynamics in changing conditions and aiming to reconstruct the entire regulatory networks by linking kinases to their physiological substrates.
The Virulence Regulator Agr Controls the Staphylococcal Capacity to Activate Human Neutrophils via the Formyl Peptide Receptor 2
2011-11-08

The Agr quorum-sensing system represents the master regulator for staphylococcal virulence factors and is known to have a strong impact on the release of pathogen-associated molecular pattern (PAMP) molecules. Among the various staphylococcal PAMPs, phenol-soluble modulin (PSM) peptides have attracted increasing interest because they are crucial for staphylococcal virulence and have neutrophil-recruiting properties. The latter depend on recognition of PSMs by the neutrophil formyl peptide receptor 2 (FPR2/ALX), for which PSMs are highly efficient agonists. We demonstrate that Agr inactivation in &lt;i&gt;Staphylococcus aureus&lt;/i&gt; or &lt;i&gt;S. epidermidis&lt;/i&gt; leads to strongly reduced neutrophil responses, which is in agreement with the previously reported strict control of PSM expression by Agr. Agr had a distinct and profound impact on activation of FPR2/ALX but not of the related FPR1 receptor that senses bacterial formylated peptides. &lt;i&gt;S. epidermidis&lt;/i&gt; PSMs had similar FPR2/ALX-activating properties but differed in their dependence on N-terminal formylation compared to &lt;i&gt;S. aureus&lt;/i&gt; PSMs. Moreover, &lt;i&gt;S. aureus&lt;/i&gt; and &lt;i&gt;S. epidermidis&lt;/i&gt; PSMs upregulated the neutrophil complement receptor CD11b via FPR2/ALX stimulation in an Agr-dependent fashion. Hence, Agr controls the capacity of staphylococcal pathogens to activate FPR2/ALX-dependent neutrophil responses, underscoring the crucial role of FPR2/ALX and PSMs in staphylococcus-host interaction.
Processing of CXCL12 by Different Osteoblast-Secreted Cathepsins
2011-11-08

Hematopoietic stem and progenitor cells (HSPCs) are known to reside in specialized niches at the endosteum in the trabecular bone. Osteoblasts are the major cell type of the endosteal niche. It is well established that secreted proteases are involved in cytokine-induced mobilization processes that release stem cell from their niches. However, migratory processes such as the regular trafficking of HSPCs between their niches and the periphery are not fully understood. In the current study we analyzed whether osteoblast-secreted cysteine cathepsins are able to reduce the direct interaction of HSPCs with bone-forming osteoblasts. Isolated human osteoblasts were shown to secrete proteolytically active cysteine cathepsins, such as cathepsins B, K, L, and X. All of these cathepsins were able to digest, although with different efficacy, the chemokine CXCL12, which is known to be important for retaining HSPCs in their niches. Of the 4 identified cathepsins, only cathepsin X was able to reduce binding of HSPCs to osteoblasts. Interestingly, nonactivated pro-cathepsin X and mature cathepsin X did not interfere with HSPC-osteoblast interactions. Only pro-cathepsin X treated with dithiothreitol, which unfolds but does not lead to full maturation of cathepsin X, significantly reduced HSPC adhesion to osteoblasts. These observations argue for a role of the accessible cathepsin X prodomain in diminishing cell binding. Our findings strongly suggest that the cysteine cathepsins B, K, and L constitutively secreted by osteoblasts are part of the fine-tuned regulation of CXCL12 in the bone marrow, whereas pro-cathepsin X with its prodomain can affect HSPC trafficking in the niche.
The p101 subunit of PI3Kγ restores activation by Gβ mutants deficient in stimulating p110γ
2011-11-08

G-protein-regulated PI3Kγ (phosphoinositide 3-kinase γ) plays a crucial role in inflammatory and allergic processes. PI3Kγ, a dimeric protein formed by the non-catalytic p101 and catalytic p110γ subunits, is stimulated by receptor-released Gβγ complexes. We have demonstrated previously that Gβγ stimulates both monomeric p110γ and dimeric p110γ/p101 lipid kinase activity in vitro. In order to identify the Gβ residues responsible for the Gβγ–PI3Kγ interaction, we examined Gβ1 mutants for their ability to stimulate lipid and protein kinase activities and to recruit PI3Kγ to lipid vesicles. Our findings revealed different interaction profiles of Gβ residues interacting with p110γ or p110γ/p101. Moreover, p101 was able to rescue the stimulatory activity of Gβ1 mutants incapable of modulating monomeric p110γ. In addition to the known adaptor function of p101, in the present paper we show a novel regulatory role of p101 in the activation of PI3Kγ.
Tell-Tale Tails: A New Approach to Estimating Unique Information Shares
2011-11-08

The trading of securities on multiple markets raises the question of each market’s share in the discovery of the informationally efficient price. We exploit salient distributional features of multivariate financial price processes to uniquely determine these contributions. In doing so, we resolve the main drawback of the widely used Hasbrouck (1995) methodology, which merely provides upper and lower bounds of a market’s information share. When these bounds diverge, as is the case in many applications, informational leadership becomes blurred. We show how tail dependence of price changes, which may emerge as a result of differences in market design, can be exploited to estimate unique information shares. Two empirical applications illustrate the benefit and practical use of the new methodology.
Naturalistic Observation in the Hispanic World and its Contribution to the Development of Comparative Psychology
2011-11-08

The observation and descriptions of animal’s behavior and emotions from the New World began shortly after the arrival of Spaniards in America. The discovery of the Indian natives and completely unknown species in Europe sparked a great interest in pioneers like Álvarez Chanca, Fernández de Oviedo, Cieza de León, Sahagún, Francisco Hernández, Acosta, Cobo or much later by Azara. In our opinion, these studies provided the basis for the study of animal behavior and emotions in the New and the Old World and allowed a new&#13;\\nunderstanding of the Natural History and the relationship between structure and function. It is likely that these findings were crucial for the work of Charles Darwin three Centuries later. Moreover, it is suggested that the future development of Comparative Psychology based on Darwin and Romanes work, based its roots in the work and observations of these early pioneers.[RESUMEN]La observación y la descripción del comportamiento y de las emociones de los animales del Nuevo Mundo se inició poco después de la llegada de los españoles en América. No solo causó asombro el encuentro con los indios nativos sino también la existencia de especies completamente desconocidas en Europa. Este descubrimiento despertó un gran interés en pioneros como Álvarez Chanca, Fernández de Oviedo, Cieza de&#13;\\nLeón, Sahagún, Francisco Hernández, Acosta, Cobo o mucho más tarde Azara. En nuestra opinión, estos&#13;\\nestudios sirvieron de base para el estudio del comportamiento animal y las emociones tanto en el Viejo Mundo como en el Nuevo y permitió una nueva comprensión de la Historia Natural y de la relación entre estructura&#13;\\ny función. Es probable que estos hallazgos iniciales fueran cruciales en los posteriores estudios de Charles&#13;\\nDarwin, tres siglos más tarde. Por otra parte, se sugiere que el desarrollo de la Psicología Comparada que se&#13;\\nproduce a partir de la segunda mitad del siglo XIX, a partir de la obra de Darwin y Romanes asientan sus en sus&#13;\\nraíces en el trabajo y las observaciones de estos pioneros.
Naturalistic Observation in the Hispanic World and its Contribution to the Development of Comparative Psychology
2011-11-08

The observation and descriptions of animal's behavior and emotions from the New World began shortly after the arrival of Spaniards in America.The discovery of the Indian natives and completely unknown species in Europe sparked a great interest in pioneers like Álvarez Chanca, Fernández de Oviedo, Cieza de León, Sahagún, Francisco Hernández, Acosta, Cobo or much later by Azara.In our opinion, these studies provided the basis for the study of animal behavior and emotions in the New and the Old World and allowed a new understanding of the Natural History and the relationship between structure and function.It is likely that these findings were crucial for the work of Charles Darwin three Centuries later.Moreover, it is suggested that the future development of Comparative Psychology based on Darwin and Romanes work, based its roots in the work and observations of these early pioneers.
Sleep and immune function
2011-11-09

Sleep and the circadian system exert a strong regulatory influence on immune functions. Investigations of the normal sleep-wake cycle showed that immune parameters like numbers of undifferentiated naïve T cells and the production of pro-inflammatory cytokines exhibit peaks during early nocturnal sleep whereas circulating numbers of immune cells with immediate effector functions, like cytotoxic natural killer cells, as well as anti-inflammatory cytokine activity peak during daytime wakefulness. Although it is difficult to entirely dissect the influence of sleep from that of the circadian rhythm, comparisons of the effects of nocturnal sleep with those of 24-h periods of wakefulness suggest that sleep facilitates the extravasation of T cells and their possible redistribution to lymph nodes. Moreover, such studies revealed a selectively enhancing influence of sleep on cytokines promoting the interaction between antigen presenting cells and T helper cells, like interleukin-12. Sleep on the night after experimental vaccinations against hepatitis A produced a strong and persistent increase in the number of antigen-specific Th cells and antibody titres. Together these findings indicate a specific role of sleep in the formation of immunological memory. This role appears to be associated in particular with the stage of slow wave sleep and the accompanying pro-inflammatory endocrine milieu that is hallmarked by high growth hormone and prolactin levels and low cortisol and catecholamine concentrations.