bluuebunny/crossref_metadata_2025_split huggingface dataset:
Package level cohesion measurement in object-oriented software
Authors: Gupta Varun , Chhabra Jitender Kumar 
Published: December 2011

AbstractPackages are re-usable components for most of object-oriented systems. To promote reuse in object-oriented systems and to make deployment and maintenance tasks easy, packages in object-oriented systems must be cohesive. Quantification of cohesion of packages can be very useful in assessing their reusability, quality etc. In this paper, a new measure for the measurement of package cohesion is proposed. The cohesion of a package is measured in terms of the degree of intra-package dependencies among its elements. The hierarchical structure of packages has also been taken into account during the measurement. The proposed measure has been validated theoretically as well as empirically. An empirical study has been conducted using 25 packages taken from six open-source software projects developed in Java. The proposed package cohesion measure is found to be a useful indicator of external quality factors such as the reusability of packages. The proposed metric is also established as a better predictor of code reusability than the existing cohesion measures.
On clique-colouring of graphs with few P4’s
Authors: Klein Sulamita , Morgana Aurora 
Published: December 2011

Abstract
Let G=(V,E) be a graph with n vertices. A clique-colouring of a graph is a colouring of its vertices such that no maximal clique of size at least two is monocoloured. A k-clique-colouring is a clique-colouring that uses k colours. The clique-chromatic number of a graph G is the minimum k such that G has a k-clique-colouring.
In this paper we will use the primeval decomposition technique to find the clique-chromatic number and the clique-colouring of well known classes of graphs that in some local sense contain few P
4’s. In particular we shall consider the classes of extended P
4-laden graphs, p-trees (graphs which contain exactly n−3 P
4’s) and (q,q−3)-graphs, q≥7, such that no set of at most q vertices induces more that q−3 distincts P
4’s. As corollary we shall derive the clique-chromatic number and the clique-colouring of the classes of cographs, P
4-reducible graphs, P
4-sparse graphs, extended P
4-reducible graphs, extended P
4-sparse graphs, P
4-extendible graphs, P
4-lite graphs, P
4-tidy graphs and P
4-laden graphs that are included in the class of extended P
4-laden graphs.
The role of between‐parent values agreement in parent‐to‐child transmission of academic values
Authors: Gniewosz Burkhard , Noack Peter 
Published: December 2011

ABSTRACTThe present study investigates the intergenerational transmission of academic task values within family in early adolescence. Social learning processes are assumed to operate through the students’ perceptions of their parents’ values. The major goal of this study is to show that this values transmission is facilitated by between‐parent value agreement.Based on a longitudinal data set including 1019 German students, their mothers (N = 847), and fathers (N = 733), structural equation models showed significant effects of the parents’ task values regarding math and German language as academic subjects on the respective task values reported by the students, mediated through the student‐perceived parental values. This transmission chain was only found if the between‐parent agreement was high.The results are discussed in terms of parent‐specific mechanisms fostering transmission if both parents agree on academic values, such as an improved perceptive accuracy as well as the increased salience and mutual reinforcement of parental messages.
Holocene and Pleistocene sea-level indicators at the coast of Jericoacoara, Ceará, NE Brazil
Authors: Irion Georg , de Morais Jáder Onofre , Bungenstock Friederike 
Published: December 2011

Beach-rock exposures provide a record of Holocene sea-level rise along the 560-km-long northeast-facing coast of Ceará, Brazil, that differs from the record available along the other 4300 km of Brazilian coastline further south. Whereas documentation is available from southern Brazil to show Holocene sea levels as much as 5 m above today's level, our observations along the northeastern coast indicate that sea level here was not above the present-day level during the Holocene. Near Jericoacoara, about 240 km northwest of Fortaleza, characterized by strong surf, Precambrian rocks crop out from under a temporary cover of sand in small protected locations with less surf. Here in this upper tidal zone beach rock is being formed, while it is being dismembered synchronously by erosion at lower tide levels. This shows a rising sea level. Along the entire coast of Ceará west of Ponta Grossa the absence of beach rock higher than spring tide level indicates that sea-level was not above its present-day level during the Holocene.Notches in bedrock situated between 2 m and 6 m above spring-tide high-water level that we formerly described as Holocene, are now believed to be Sangamonian.
Simulation of a propelled wake with moderate excess momentum in a stratified fluid
Authors: de Stadler Matthew B. , Sarkar Sutanu 
Published: December 2011

AbstractDirect numerical simulation is used to simulate the turbulent wake behind an accelerating axisymmetric self-propelled body in a stratified fluid. Acceleration is modelled by adding a velocity profile corresponding to net thrust to a self-propelled velocity profile resulting in a wake with excess momentum. The effect of a small to moderate amount of excess momentum on the initially momentumless self-propelled wake is investigated to evaluate if the addition of excess momentum leads to a large qualitative change in wake dynamics. Both the amount and shape of excess momentum are varied. Increasing the amount of excess momentum and/or decreasing the radial extent of excess momentum was found to increase the defect velocity, mean kinetic energy, shear in the velocity gradient and the wake width. The increased shear in the mean profile resulted in increased production of turbulent kinetic energy leading to an increase in turbulent kinetic energy and its dissipation. Slightly larger vorticity structures were observed in the late wake with excess momentum although the differences between vorticity structures in the self-propelled and 40 % excess momentum cases was significantly smaller than suggested by previous experiments. Buoyancy was found to preserve the doubly inflected velocity profile in the vertical direction, and similarity for the mean velocity and turbulent kinetic energy was found to occur in both horizontal and vertical directions. While quantitative differences were observed between cases with and without excess momentum, qualitatively similar evolution was found to occur.
Determinants of livelihood strategy variation in two extractive reserves in Amazonian flooded and unflooded forests
Authors: NEWTON PETER , ENDO WHALDENER , PERES CARLOS A. 
Published: December 2011

SUMMARYExtractive reserves account for a significant proportion of the remaining intact forest within Brazilian Amazonia. Managers of extractive reserves need to understand the livelihood strategies adopted by rural Amazonians in order to implement projects that benefit the livelihoods of local residents whilst maintaining forest integrity. Whilst resident populations are often descended from immigrant rubber-tappers, dynamic economic and social conditions have led to a recent diversification of land-use practices. This two-year study in two large contiguous extractive reserves encompassing both unflooded (terra firme) and seasonally flooded (várzea) forest, shows the degree to which local livelihood strategies of different settlements are heterogeneous. Extractive offtake of forest products and fish catches and agricultural activities, together with income from sales, for 82 households in 10 communities were quantified in detail by means of weekly surveys. The survey data were combined with interviews to examine the demographic and wealth profile, and engagement in alternative activities, in 181 households across 27 communities. All households and communities were engaged in all three subsistence activity types, but there was large variation in engagement with income-generating activities. Households within a community showed considerable congruence in their income-generating activity profiles, but there was significant variation between communities. Yields from agriculture and fishing were more temporally stable than extraction of highly-seasonal forest products. Generalized linear mixed models showed that forest type was consistently important in explaining yields of both agrarian and extractive products. Communities with greater access to terra firme forest were inherently more agricultural, and strongly committed to manioc production. Communities with greater access to flooded forest, however, showed a greater dependence on fishing. Conservation should be more attuned to the diversity and dynamism of livelihood strategies in protected areas; in particular, reserve managers and policy makers should account for the effect of local variation in physical geography when designing sustainable development projects.
Age grading in the Montréal French inflected future
Authors: Wagner Suzanne Evans , Sankoff Gillian 
Published: December 2011

AbstractThe rise of the periphrastic future (PF) at the expense of the inflected future (IF) is an established historical trend in Québécois French over at least the past 150 years. Previous research has also found higher rates of PF among younger speakers, many displaying categorical use in affirmative contexts. Because an apparent time interpretation of the synchronic data fits the historical record, we expected concomitant speaker stability across the lifespan. On the contrary, our panel study of 60 Montréal speakers (1971–1984) reveals age grading in a retrograde direction. As they aged, two-thirds of the speakers we studied increased their frequency of IF, an effect heightened for members of higher socioprofessional groups. Though not sufficiently robust to stem the historical tide, increased IF use by older speakers may retard the change somewhat, providing continuing IF input to child L1 acquisition. Rather than vitiating an apparent time interpretation, these results indicate that the rate of change may be slightly overestimated if age grading acts in a retrograde direction.
Who consumed 5 or more portions of fruit and vegetables per day in 1986–1987 and in 2000–2001?
Authors: Rogers Stephen , Pryer Jane A 
Published: December 2011

AbstractObjectiveThe aim of the study was to describe who ate 5 or more portions of fruit and vegetables per day (‘compliers’) in 1986–1987 and in 2000–2001.DesignWe used data from the Dietary and Nutritional Surveys of British Adults. Each is a nationally representative dietary survey using 7 d weighed food records for men and women, aged 16–64 years, living in private households in Great Britain in 1986–1987 and in 2000–2001.SettingGreat Britain.SubjectsData were analysed for 2197 adults in 1986–1987 and 1724 adults in 2000–2001.ResultsIn 1986–1987 12·7 % were classified as ‘compliers’ compared with 16·5 % in 2000–2001. Manual social classes, younger participants and people on benefits or outside paid employment were less likely to be ‘compliers’. Being divorced, widowed or separated was negatively related to being a ‘complier’, as was being in a household with dependant children or a lone parent with dependant children. Between 1986–1987 and 2000–2001 improvements were seen across social class groups and differences between men and women and between regions were reduced.ConclusionsOnly 12·7 % participants in the Dietary and Nutritional Surveys of British Adults were classified as ‘compliers’ in 1986–1987 compared with 16·5 % in 2000–2001. There have been some important changes in the distribution of ‘compliers’, but the low levels overall support the need for a reinvigorated policy drive to improve compliance with fruit and vegetable goals.
The Molecular Universe
Authors: Tielens A. G. G. M. 
Published: December 2011

AbstractOver the last 20 years, we have discovered that we live in a molecular Universe: A Universe with a rich and varied organic inventory; A Universe where molecules are abundant and widespread; A Universe where molecules play a central role in key processes that dominate the structure and evolution of galaxies; A Universe where molecules provide convenient thermometers and barometers to probe local physical conditions; A Universe where molecules can work together to form such complex species as you and me. Understanding the origin and evolution of interstellar and circumstellar molecules is thus key to understanding the Universe around us and our place in it and has become a fundamental goal of modern astrophysics. This review focuses on the organic inventory and the chemical processes that may play a role in stablishing molecular complexity in regions of planet formation.
Hydrodynamical-Chemical Models from Prestellar Cores to Protostellar Cores
Authors: Aikawa Yuri , Furuya Kenji , Wakelam Valentine , Hersant Frank , Matsumoto Tomoaki , Saigo Kazuya , Tomida Kengo , Tomisaka Koji , Garrod Robin , Herbst Eric 
Published: December 2011

AbstractWe investigate the molecular evolution in star forming cores from dense cloud cores (nH ~ 104 cm−3, T ~ 10 K) to protostellar cores. A detailed gas-grain reaction network is solved in infalling fluid parcels in 1-D radiation hydrodynamic model. Large organic molecules are mainly formed via grain-surface reaction at T ~ several 10 K and sublimated to the gas-phase at ~ 100 K, while carbon-chain species are formed at a few 10 K after the sublimation of CH4 ice. The former accounts for the high abundance of large organic molecules in hot corinos such as IRAS16293, and the latter accounts for the carbon chain species observed toward L1527. The relative abundance of carbon chain species and large organic species would depend on the collapse time scale and/or temperature in the dense core stage. The large organic molecules and carbon chains in the protostellar cores are heavily deuterated; although they are formed in the warm temperatures, their ingredients have high D/H ratios, which are set in the cold core phase and isothermal collapse phase. HCOOH is formed by the gas-phase reaction of OH with the sublimated H2CO, and is further enriched in Deuterium due to the exothermic exchange reaction of OH + D → OD + H.In the fluid parcels of the 1-D collapse model, warm temperature T. ~ several 10 K lasts for only ~ 104 yr, and the fluid parcels fall to the central star in ~ 100 yr after the temperature of the parcel rises to T ≥ 100 K. These timescales are determined by the size of the warm region and infall (~ free-fall) velocity: rwarm/tff. In reality, circum stellar disk is formed, in which fluid parcels stay for a longer timescale than the infall timescale. We investigate the molecular evolution in the disk by simply assuming that a fluid parcel stays at a constant temperature and density (i.e. a fixed disk radius) for 104 − 105 yrs. We found that some organic species which are underestimated in our 1-D collapse model, such as CH3OCH3 and HCOOCH3, become abundant in the disk. We also found that these disk species have very high D/H ratio as well, since their ingredients are highly deuterated.Finally we investigate molecular evolution in a 3D hydrodynamic simulation of star forming core. We found CH3OH are abundant in the vicinity of the first core. The abundances of large organic species are determined mainly by the local temperature (sublimation), because of the short lifetime of the first core and the efficient mass accretion via angular momentum transfer.
Models of Hot Cores with Complex Molecules
Authors: Weaver Susanna L. Widicus , Garrod Robin T. , Laas Jacob C. , Herbst Eric 
Published: December 2011

AbstractRecent models of hot cores have incorporated previously-uninvestigated chemical pathways that lead to the formation of complex organic molecules (COMs; i.e. species containing six or more atoms). In addition to the gas-phase ion-molecule reactions long thought to dominate the organic chemistry in these regions, these models now include photodissociation-driven grain surface reaction pathways that can also lead to COMs. Here, simple grain surface ice species photodissociate to form small radicals such as OH, CH3, CH2OH, CH3O, HCO, and NH2. These species become mobile at temperatures above 30 K during the warm-up phase of star formation. Radical-radical addition reactions on grain surfaces can then form an array of COMs that are ejected into the gas phase at higher temperatures. Photodissociation experiments on pure and mixed ices also show that these complex molecules can indeed form from simple species. The molecules predicted to form from this type of chemistry reasonably match the organic inventory observed in high mass hot cores such as Sgr B2(N) and Orion-KL. However, the relative abundances of the observed molecules differ from the predicted values, and also differ between sources. Given this disparity, it remains unclear whether grain surface chemistry governed by photodissociation is the dominant mechanism for the formation of COMs, or whether other unexplored gas-phase reaction pathways could also contribute significantly to their formation. The influence that the physical conditions of the source have on the chemical inventory also remains unclear. Here we overview the chemical pathways for COM formation in hot cores. We also present new modeling results that begin to narrow down the possible routes for production of COMs based on the observed relative abundances of methyl formate (HCOOCH3) and its C2H4O2 structural isomers.
Molecules in Bipolar Outflows
Authors: Tafalla Mario , Bachiller Rafael 
Published: December 2011

AbstractBipolar outflows constitute some of the best laboratories to study shock chemistry in the interstellar medium. A number of molecular species have their abundance enhanced by several orders of magnitude in the outflow gas, likely as a combined result of dust mantle disruption and high temperature gas chemistry, and therefore become sensitive indicators of the physical changes taking place in the shock. Identifying these species and understanding their chemical behavior is therefore of high interest both to chemical studies and to our understanding of the star-formation process. Here we review some of the recent progress in the study of the molecular composition of bipolar outflows, with emphasis in the tracers most relevant for shock chemistry. As we discuss, there has been rapid progress both in characterizing the molecular composition of certain outflows as well as in modeling the chemical processes likely involved. However, a number of limitations still affect our understanding of outflow chemistry. These include a very limited statistical approach in the observations and a dependence of the models on plane-parallel shocks, which cannot reproduce the observed wing morphology of the lines. We finish our contribution by discussing the chemistry of the so-called extremely high velocity component, which seems different from the rest of the outflow and may originate in the wind from the very vicinity of the protostar.
Long-Range Interaction Potential of Open Shell Atoms with Neutral Molecules : Application to the Calculation of the Rate Constant for the C2H(2Σ+)+O(3P) Reaction
Authors: Georgievskii Yuri , Klippenstein Stephen J. 
Published: December 2011

AbstractAn accurate knowledge of the long-range interaction potential for the ground and first few excited electronic states is needed for quantitative prediction of the rate coefficients for astrochemical reactions at low temperatures. Some reactions important for astrochemical modeling include an open-shell atom as one of the fragments. Due to the interplay between the spin-orbit and quadrupole interactions such reactions require a special treatment. In this paper we derive the general expressions for the energy levels for such systems, apply them to the C2H(2Σ+)+O(3P) reaction, and compare the results with ab initio calculations.
Solid State Pathways towards Molecular Complexity in Space
Authors: Linnartz Harold , Bossa Jean-Baptiste , Bouwman Jordy , Cuppen Herma M. , Cuylle Steven H. , van Dishoeck Ewine F. , Fayolle Edith C. , Fedoseev Gleb , Fuchs Guido W. , Ioppolo Sergio , Isokoski Karoliina , Lamberts Thanja , Öberg Karin I. , Romanzin Claire , Tenenbaum Emily , Zhen Junfeng 
Published: December 2011

AbstractIt has been a long standing problem in astrochemistry to explain how molecules can form in a highly dilute environment such as the interstellar medium. In the last decennium more and more evidence has been found that the observed mix of small and complex, stable and highly transient species in space is the cumulative result of gas phase and solid state reactions as well as gas-grain interactions. Solid state reactions on icy dust grains are specifically found to play an important role in the formation of the more complex “organic” compounds. In order to investigate the underlying physical and chemical processes detailed laboratory based experiments are needed that simulate surface reactions triggered by processes as different as thermal heating, photon (UV) irradiation and particle (atom, cosmic ray, electron) bombardment of interstellar ice analogues. Here, some of the latest research performed in the Sackler Laboratory for Astrophysics in Leiden, the Netherlands is reviewed. The focus is on hydrogenation, i.e., H-atom addition reactions and vacuum ultraviolet irradiation of interstellar ice analogues at astronomically relevant temperatures. It is shown that solid state processes are crucial in the chemical evolution of the interstellar medium, providing pathways towards molecular complexity in space.
Recent Results of Solid-State Spectroscopy
Authors: Jäger Cornelia , Posch Thomas , Mutschke Harald , Zeidler Simon , Tamanai Akemi , de Vries Bernard L. 
Published: December 2011

AbstractSolid state spectroscopy continues to be an important source of information on the mineralogical composition and physical properties of dust grains both in space and on planetary surfaces. With only a few exceptions, artificially produced or natural terrestrial analog materials, rather than ‘real’ cosmic dust grains, are the subject of solid state astrophysics. The Jena laboratory has provided a large number of data sets characterizing the UV, optical and infrared properties of such cosmic dust analogs. The present paper highlights recent developments and results achieved in this context, focussing on ‘non-standard conditions’ such as very low temperatures, very high temperatures and very long wavelengths.