bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Natural and Pretreated Soybean Hulls on Enzyme Production by Trichoderma reesei
Authors: Coffman Anthony M. , Li Qian , Ju Lu‐Kwang
Published: May 2014

The enzyme induction utility of soybean hulls (SBH), consisting in excess of 50 wt% non‐starch polysaccharides (NSP) cellulose, hemicellulose, and pectin, was studied through cultivation of the carbohydrase‐producing fungus Trichoderma reesei Rut C‐30. Shake flask systems of T. reesei were grown in a medium consisting of defatted soybean flour as a nitrogen source and SBH, some of which were untreated and others pretreated by liquid hot water, alkaline, and supercritical carbon dioxide, as carbon source. Cellulase, xylanase, and polygalacturonase activities were measured for the systems, and the natural hull systems were found to yield optimum enzyme production. Controlled batch fermentation experiments were carried out to compare enzyme production resulting from media with Avicel® (FMC BioPolymer, Philadelphia, PA, USA) versus natural SBH with and without soybean flour as the nitrogen source. Soybean hull fermentations were also performed at several pH levels to observe the effects on enzyme production. Soybean hulls induced comparable levels of cellulase, and higher levels of xylanase and polygalacturonase, than Avicel®. With SBH, cellulase and xylanase production were enhanced at higher pH levels (6.0), and polygalacturonase was enhanced at lower pH levels (4.0–4.5). Enzyme production was largely unaffected by the presence of soybean flour as the nitrogen source.
You're Fired!: The Impact of Race on the Firing of Black Head Coaches in Major College Football
Authors: Kopkin Nolan A.
Published: May 2014

It is well known that the hiring rate of black head coaches in major college football is not representative of the number of student-athletes that are black. However, less obvious is the fact that black head coaches may be treated unfairly when decisionmakers decide whether to retain or fire their institution's current head coach. In this paper, I use a rich dataset of National Collegiate Athletic Associate football coaches from 1990 to 2012, containing measures of coaching performance and school expectations, as well as information on each coach's race and whether he was fired or retained in each season. Using this data, I estimate a discrete-time hazard model of the probability that a head coach is fired, allowing the hazard rate of black head coaches and white head coaches to differ, and find that black head coaches are 5.28 percentage points more likely to be fired than their white counterparts. Additionally, I find that black head coaches are more likely to be fired in the initial 3 years of tenure, and again in their seventh and eighth years, but that the difference in the probability of release between black and white head coaches in the fourth through sixth years of tenure is small and statistically insignificant.
Towards improved coverage of Southeast Asian Englishes in the 'Oxford English Dictionary'
Authors: Salazar Danica
Published: May 2014

This paper examines the lexicon of Southeast Asian varieties of English and its representation in the Oxford English Dictionary (OED). It begins by describing the OED’s changing editorial policies with regard to words originating from outside of Britain. It then focusses on Southeast Asian words included in the OED’s third and latest edition, and on recent efforts to improve the OED’s handling of this type of vocabulary. The paper concludes with a discussion of the key issues that need to be addressed to ensure adequate treatment of Southeast Asian and other World Englishes in the OED: overcoming the shortage of written resources through targeted and collaborative research programmes, providing better regional labelling through the comparative study of the lexis of national and regional varieties, anddiversifying the OED’s coverage of Southeast Asian Englishes by including words and meanings of more current usage, as well as lexical innovations beyond simple borrowing.
Functional characterization of aPlagiochasma appendiculatumflavone synthase I showing flavanone 2‐hydroxylase activity
Authors: Han Xiao-Juan , Wu Yi-Feng , Gao Shuai , Yu Hai-Na , Xu Rui-Xue , Lou Hong-Xiang , Cheng Ai-Xia
Published: May 2014

FNS I is a 2‐oxoglutarate dependent dioxygenase (2‐ODD) found mainly in species of the Apiaceae family. Here, anFNS IcDNA sequence was isolated from the liverwortPlagiochasma appendiculatum(Aytoniaceae) and characterized. The recombinant protein exhibited high FNS I activity catalyzing the conversion of naringenin to apigenin and 2‐hydroxynaringenin. The critical residue for flavanone‐2‐hydroxylation activity was Tyr240, as identified from homology modeling and site‐directed mutagenesis. The recombinant protein also showed some flavonol synthase activity, as it can convert dihydrokaempferol to kaempferol. When the Leu311 residue was mutated to Phe, the enzyme's capacity to convert dihydrokaempferol to kaempferol was substantially increased. PaFNS I represents a 2‐ODD in which a hydrophobic π‐stacking interaction between the key residue and the naringenin A‐ring determines 2‐hydroxyflavanone formation.
Susceptibility of the conventional criteria for mild cognitive impairment to false‐positive diagnostic errors
Authors: Edmonds Emily C. , Delano‐Wood Lisa , Clark Lindsay R. , Jak Amy J. , Nation Daniel A. , McDonald Carrie R. , Libon David J. , Au Rhoda , Galasko Douglas , Salmon David P. , Bondi Mark W. ,   Alzheimer's Disease Neuroimaging Initiative
Published: May 2014

Background

We assessed whether mild cognitive impairment (MCI) subtypes could be empirically derived within the Alzheimer's Disease Neuroimaging Initiative (ADNI) MCI cohort and examined associated biomarkers and clinical outcomes.

Methods

Cluster analysis was performed on neuropsychological data from 825 MCI ADNI participants.

Results

Four subtypes emerged: (1) dysnomic (n = 153), (2) dysexecutive (n = 102), (3) amnestic (n = 288), and (4) cluster‐derived normal (n = 282) who performed within normal limits on cognitive testing. The cluster‐derived normal group had significantly fewer APOE ε4 carriers and fewer who progressed to dementia compared with the other subtypes; they also evidenced cerebrospinal fluid Alzheimer's disease biomarker profiles that did not differ from the normative reference group.

Conclusions

Identification of empirically derived MCI subtypes demonstrates heterogeneity in MCI cognitive profiles that is not captured by conventional criteria. The large cluster‐derived normal group suggests that conventional diagnostic criteria are susceptible to false‐positive errors, with the result that prior MCI studies may be diluting important biomarker relationships.
Successfully Eliminating Chest Radiography by Replacing It With Dual Vector Technology and an Algorithm for PICC Placement
Authors: Girgenti Constance , Donnellan Elizabeth
Published: May 2014

It can be difficult to get the tip of a central vascular access device to the targeted area of the caval-atrial junction accurately and precisely when placing a device at the bedside. Tip placement outside this precise location can lead to complications and poor patient outcomes. Malpositions increase patients' radiation exposure, increase costs, and delay treatment. The current standard of using chest radiography to check tip placement has demonstrated discrepancies and is subject to interpretation differences between radiologists. Chest radiography and malpositions can be eliminated with the use of technology that includes Doppler, echocardiography (ECG), and an algorithm. This technology can reduce the cost of labor and supplies in addition to allowing the use of a central vascular access device immediately after placement.
Putting Copyright in Its Place1
Authors: Piper Tina
Published: May 2014

As copyright is asked to perform a greater role in governing creative activity, its focus on economic values above all others raises concerns. Interviews conducted by the author with Canadian independent music labels suggest that the law and the norms governing labels’ operations are more diverse and include direct subsidies, or grants, from government and the private sector. These grants perform many of the functions expected from copyright. This study concludes that copyright law is often exotic, peripheral, and even irrelevant to those involved in the spheres of remunerative Canadian sound production considered here. This finding suggests a renewed focus on a Canadian narrative of copyright law that puts it in its place alongside other instruments regulating independent music production.
Coalitional Dynamics, Power Structure and Financial Markets in East Asia
Authors: Zhang Xiaoke
Published: May 2014

The main argument to be developed in this article posits that fundamental changes and variations in the financial market structure of East Asian economies have been predicated on the emergence and configuration of the dominant coalitions. The coalitions have been forged by private market agents, economic policymakers and political elites who have developed particular interests in financial market changes as a response to economic and political imperatives both at home and abroad. In East Asia, the dominant coalitions that have borne crucially on regulatory rules and market practices have differed in the policy preferences of key actors in the coalitions and the power structures of these coalitions. It is these differences that have exerted divergent shaping influences on financial market development.
Water droplet condensation and evaporation in turbulent channel flow
Authors: Russo E. , Kuerten J. G. M. , van der Geld C. W. M. , Geurts B. J.
Published: May 2014

We propose a point-particle model for two-way coupling of water droplets dispersed in the turbulent flow of a carrier gas consisting of air and water vapour. We adopt an Euler–Lagrangian formulation based on conservation laws for the mass, momentum and energy of the continuous phase and on empirical correlations describing momentum, heat and mass transfer between the droplet phase and the carrier gas phase. An incompressible flow formulation is applied for direct numerical simulation of differentially heated turbulent channel flow. The two-way coupling is investigated in terms of its effects on mass and heat transfer characteristics and the resulting droplet size distribution. Compared to simulations without droplets or those with solid particles with the same size and specific heat as the water droplets, a significant increase in Nusselt number is found, arising from the additional phase changes. The Nusselt number increases with increasing ambient temperature and is almost independent of the heat flux applied to the walls of the channel. The time-averaged droplet size distribution displays a characteristic dependence on position expressing the combined effect of turbophoresis and phase changes in turbulent wall-bounded flow. In the statistically steady state that is reached after a long time, the resulting flow exhibits a mean motion of water vapour from the warm wall to the cold wall, where it condenses on average, followed by a net mean mass transfer of droplets from the cold wall to the warm wall.
Stability of downflowing gyrotactic microorganism suspensions in a two-dimensional vertical channel
Authors: Hwang Yongyun , Pedley T. J.
Published: May 2014

Hydrodynamic focusing of cells along the region of the most rapid flow is a robust feature in downflowing suspensions of swimming gyrotactic microorganisms. Experiments performed in a downward pipe flow have reported that the focused beam-like structure of the cells is often unstable and results in the formation of regular-spaced axisymmetric blips, but the mechanism by which they are formed is not well understood. To elucidate this mechanism, in this study, we perform a linear stability analysis of a downflowing suspension of randomly swimming gyrotactic cells in a two-dimensional vertical channel. On increasing the flow rate, the basic state exhibits a focused beam-like structure. It is found that this focused beam is unstable with the varicose mode, the spatial structure, wavelength, phase speed and behaviour with the flow rate of which are remarkably similar to those of the blip instability in the pipe flow experiment. To understand the physical mechanism of the varicose mode, we perform an analysis which calculates the term-by-term contribution to the instability. It is shown that the leading physical mechanism in generating the varicose instability originates from the horizontal gradient in the cell-swimming-vector field formed by the non-uniform shear in the base flow. This mechanism is found to be supplemented by cooperation with the gyrotactic instability mechanism observed in uniform suspensions.
Surface Instabilities on a Thin Power-Law Fluid During Spin Coating
Authors: Chen C.-I. , Lin M.-C. , Chen C.-K.
Published: May 2014

The phenomena of surface instabilities in a thin power-law fluid during spin coating are investigated. The set of Navier-Stokes equations with non-Newtonian behavior in the region of low Reynolds number serves as a mathematical description of the physical systems. Long-wave perturbation analysis is proposed to derive an evolution equation of the Ostwald de-Waele type fluid to govern the propagation of surface waves. Weakly nonlinear dynamics of film flow is studied by the multiple scales method. The amplitude of instability is determined by a Ginzburg-Landau equation. The study reveals that the degree of power-law index plays a vital role in stabilizing the film flow. The shear-thinning fluid is more unstable than the shear-thickening fluid in the stability analysis. Further, the nonlinear wave speed in the supercritical stability region decreases with increasing values of power-law index.
From primary metaphors to the complex semantic pole of grammatical constructions
Authors: HUELVA UNTERNBÄUMEN ENRIQUE
Published: May 2014

abstract

The main aim of the present work is to demonstrate that the semantic pole of ditransitive constructions manifests itself as a multidomain matrix, consisting basically of a set of conceptual metaphors integrated through the mechanism of blending. The metaphors that participate in these multidomain matrices are, in principle, metaphors that already exist in our conceptual structure. As we shall demonstrate in the course of the analysis, these often involve primary metaphors, conceived of as metaphors that have a direct, independent, experiential base. In other cases, the starting point for the construction of such multidomain matrices is complex metaphors already existing in our conceptual structure, understood as an autonomous conceptual complex of a metaphorical nature, created through the integration of various primary metaphors. Our concrete object of analysis consists of the semantic pole of different types of ditransitive constructions. The data analyzed include examples from Romance (Catalan, French, Brazilian Portuguese, and Spanish) and Germanic (English and German) languages.
The reliability of an adolescent dietary pattern identified using reduced-rank regression: comparison of a FFQ and 3 d food record
Authors: Appannah Geeta , Pot Gerda Karolien , O'Sullivan Therese Anne , Oddy Wendy Hazel , Jebb Susan Ann , Ambrosini Gina Leslie
Published: May 2014

Despite the increasing use of dietary patterns (DP) to study diet and health outcomes, relatively few studies have examined the reliability of DP using different dietary assessment methods. Reduced-rank regression (RRR) is an emerging statistical method that incorporates a priori information to characterise DP related to specific outcomes of interest. The aim of the present study was to compare DP identified using the RRR method in a FFQ with those in a 3 d food record (FR). Participants were 783 adolescents from the Western Australian Pregnancy (Raine) Cohort Study who completed both a FFQ and FR at 14 years of age. A similar ‘energy-dense, high-fat and low-fibre’ DP was identified in the FFQ and FR that was characterised by high intakes of processed meat and sugar-sweetened beverages, and low intakes of vegetables and fresh fruit. Nutrient profiles for this DP were consistent in the FFQ and FR. Pearson's correlation coefficient between participants' z-scores for the DP identified in the FFQ and FR was 0·35 for girls and 0·49 for boys (P< 0·05). The mean difference between DP z-scores derived from the FFQ and FR was − 0·08 (95 % CI − 0·21, 0·04) for girls and − 0·05 (95 % CI − 0·17, 0·07) for boys. The 95 % limits of agreement were − 2·55 to 2·39 for girls and − 2·52 to 2·41 for boys. These findings suggest that very similar DP may be identified and their z-scores show modest agreement when applying the RRR method to dietary intake data collected from adolescents using a FFQ or FR.
Dietary PUFA and cancer
Authors: Abel S. , Riedel S. , Gelderblom W. C. A.
Published: May 2014

The aim of the present paper is to give a brief overview on the role of dietary fat in carcinogenesis and as possible anticancer agents. Dietary fat is an essential nutrient and important source for the essential fatty acids (FA), linoleic and α-linolenic acids, which contribute to proper growth and development. However, dietary fat has been associated with the development of colorectal, breast, prostate, endometrial and ovarian cancers, with the type and quality of fat playing an underlying role. Tumour growth is the disruption of the homoeostatic balance regulating cell differentiation, proliferation and apoptosis and is associated with altered lipid metabolism. Animal cancer models and human cancer biopsy tissue demonstrate that a characteristic lipid profile is associated with the growth and development of neoplastic lesions. This entails alterations in membrane cholesterol, phospholipid and PUFA metabolism. Particularly, alterations in cell membrane FA metabolism involving then-6 andn-3 PUFA, are associated with changes in membrane structure, function, cellular oxidative status, activity of enzymes and signalling pathways. These events are a driving force in sustaining the altered growth of cancerous lesions and provide unique targets for intervention/cancer modulation. Challenges in utilising FA in cancer modulation exist regarding intake and effect on cell structure and biochemical interactions within the cell in the prevention of cancer development. Therefore, utilising dietary PUFA in a specificn-6:n-3 ratio may be an important chemopreventive tool in altering the growth characteristics of cancer cells.
Augustine and Ibn Sina on Souls in the Afterlife
Authors: Matthews Gareth
Published: May 2014

This paper examines significant similarities between the views of Augustine and Ibn Sina on the soul's knowledge of itself. But there is also an intriguing difference. Ibn Sina wanted to be able to supply a satisfying account of the individuation of souls in the afterlife but was unable to provide it. Augustine, by contrast, though seemingly not especially interested in supplying any such account, nevertheless attributed to separated souls a desire to return to their very own bodies, which suggests a way of developing such an account.
Neuro-fuzzy adaptive control of a revolute stewart platform carrying payloads of unknown inertia
Authors: Eftekhari Mojtaba , Eftekhari Mahdi , Karimpour Hossein
Published: May 2014

In this research, a Stewart parallel platform with rotary actuators is simulated and a prototype is tested under different operative conditions. The purpose is to make the robot robust against inertia variations considering the fact that different payloads of unknown size may be transported. Due to the complexity issued by expressing the equations of motion with independent variables, the governing equations are derived by Lagrange's method using Lagrange multipliers for imposing the kinematic constraints imposed on this parallel robot. Eliminating Lagrange multipliers by projecting the equations onto the orthogonal complement of the space of constraints, the equations of motion are transformed to a reduced form suitable for the purpose of controller design. The control approach considered here is based on a neuro-fuzzy interference method. As a first step, each revolute arm link are individually trained under different loadings and diverse maneuvers. It is purposed that once employed together, the links will have learned how to collaborate with each others for performing a common task. Training data are divided to several clusters by using a subtractive clustering algorithm. For every cluster, a fuzzy rule is derived so that the output follows the desired trajectory. In the last stage, these rules are employed by utilizing back propagation algorithms and the effectiveness of the neuro-fuzzy system becomes approved by performing multiple maneuvers and its robustness is checked under various inertia loads. The controller has ultimately been implemented on a prototype of the Stewart mechanism in order to analyze the reliability and feasibility of the method.
A novel self-adaptive modified bat fuzzy sliding mode control of robot manipulator in presence of uncertainties in task space
Authors: Veysi Mohammad , Soltanpour Mohammad Reza , Khooban Mohammad Hassan
Published: May 2014

In this paper, an optimal fuzzy sliding mode controller has been designed for controlling the end-effector position in the task space. In the proposed control, feedback linearization method, sliding mode control, first-order fuzzy TSK system and optimization algorithm are utilized. In the proposed controller, a novel heuristic algorithm namely self-adaptive modified bat algorithm (SAMBA) is employed. To achieve an optimal performance, the parameters of the proposed controller as well as the input membership functions are optimized by SAMBA simultaneously. In this method, the bounds of structural and non-structural uncertainties are reduced by using feedback linearization method, and to overcome the remaining uncertainties, sliding mode control is employed. Mathematical proof demonstrates that the closed loop system with the proposed control has global asymptotic stability. The presence of sliding mode control gives rise to the adverse phenomenon of chattering in the end-effector position tracking in the task space. Subsequently, to prevent the occurrence of chattering in control input, a first-order TSK fuzzy approximator is utilized. Finally, to determine the fuzzy sliding mode controller coefficients, the optimization algorithm of Self-Adaptive Modified Bat is employed. To investigate the performance of the proposed control, a two-degree-of-freedom manipulator is used as a case study. The simulation results indicate the favorable performance of the proposed method.
Increased prevalence of group A streptococcus isolates in streptococcal toxic shock syndrome cases in Japan from 2010 to 2012
Authors: IKEBE T. , TOMINAGA K. , SHIMA T. , OKUNO R. , KUBOTA H. , OGATA K. , CHIBA K. , KATSUKAWA C. , OHYA H. , TADA Y. , OKABE N. , WATANABE H. , OGAWA M. , OHNISHI M.
Published: May 2014

Streptococcal toxic shock syndrome (STSS) is a severe invasive infection characterized by the sudden onset of shock, multi-organ failure, and high mortality. In Japan, appropriate notification measures based on the Infectious Disease Control law are mandatory for cases of STSS caused byβ-haemolytic streptococcus. STSS is mainly caused by group A streptococcus (GAS). Although an average of 60–70 cases of GAS-induced STSS are reported annually, 143 cases were recorded in 2011. To determine the reason behind this marked increase, we characterized theemmgenotype of 249 GAS isolates from STSS patients in Japan from 2010 to 2012 and performed antimicrobial susceptibility testing. The predominant genotype was found to beemm1, followed byemm89,emm12,emm28,emm3, andemm90. These six genotypes constituted more than 90% of the STSS isolates. The number ofemm1,emm89,emm12, andemm28isolates increased concomitantly with the increase in the total number of STSS cases. In particular, the number ofmefA-positiveemm1isolates has escalated since 2011. Thus, the increase in the incidence of STSS can be attributed to an increase in the number of cases associated with specific genotypes.
Affect and willingness to communicate in digital game-based learning
Authors: Reinders Hayo , Wattana Sorada
Published: May 2014

The possible benefits of digital games for language learning and teaching have received increasing interest in recent years. Games are said, amongst others, to be motivating, to lower affective barriers in learning, and to encourage foreign or second language (L2) interaction. But how do learners actually experience the use of games? What impact does gameplay have on students’ perceptions of themselves as learners, and how does this affect their learning practice? These questions are important as they are likely to influence the success of digital game-based language learning, and as a result the way teachers might integrate games into the curriculum. In this study we investigated the experiences of five students who had participated in a fifteen-week game-based learning program at a university in Thailand. We conducted six interviews with each of them (for a total of 30 interviews) to identify what impact gameplay had in particular on their willingness to communicate in English (MacIntyre, Dörnyei, Clément & Noels, 1998). The results showed that gameplay had a number of benefits for the participants in this study, in particular in terms of lowering their affective barriers to learning and increasing their willingness to communicate. We discuss the implications of these results in terms of further research and classroom practice.
Taiwanese montaneSambucus chinensisseeds require warm stratification, contrasting with other congeneric temperate members
Authors: Chen Shun-Ying , Chien Ching-Te , Hidayati Siti N. , Walck Jeffrey L.
Published: May 2014

Many temperate plant genera, likeSambucus, have species with range disjunctions among North America, Europe and/or Asia. Cold stratification (sometimes in combination with warm stratification) is the primary mechanism to break seed dormancy in these species. For some of these genera showing Northern Hemispheric disjunctions, members also occur in subtropical or tropical regions, mostly confined to higher elevations where climate and vegetation differ from those in northern latitudes. We made two hypotheses concerning germination for the subtropical TaiwaneseSambucus chinensis: (1) seeds from populations exposed to warm temperatures would require warm stratification, and (2) seeds from populations exposed to cold temperatures need cold stratification. We investigated the germination (including embryo growth) of non-stratified seeds over a range of temperatures and tested the effects of cold stratification and of gibberellins GA3and GA4on germination. The amount and timing of germination among populations varied substantially in response to temperature treatments. Seeds from all populations of this species required warm temperatures for dormancy break and germination, regardless of environmental conditions. As such, the majority of seeds had non-deep simple morphophysiological dormancy, which, until now, has not been reported in any members ofSambucus. The seed characteristics of the subtropicalS. chinensisare different from those of temperate members of the genus in which cold stratification is the predominate treatment to overcome dormancy.
THE EVOLUTION OF TAXES AND HOURS WORKED IN AUSTRIA, 1970–2005
Authors: Dalton John T.
Published: May 2014

Aggregate hours worked per working-age person decreased in Austria by 25% from 1970 to 2005. During the same time period, taxes increased, particularly the effective marginal tax rate on labor income. Using a standard general equilibrium growth model with taxes, I quantitatively assess the role played by the evolution of taxes in the evolution of hours worked in Austria. The model accounts for 76% of the observed decrease in hours worked per working-age person. My results are in line with other studies, which find taxes play an important role in explaining aggregate hours worked.
Lower complexity bounds for lifted inference
Authors: JAEGER MANFRED
Published: May 2014

One of the big challenges in the development of probabilistic relational (or probabilistic logical) modeling and learning frameworks is the design of inference techniques that operate on the level of the abstract model representation language, rather than on the level of ground, propositional instances of the model. Numerous approaches for such “lifted inference” techniques have been proposed. While it has been demonstrated that these techniques will lead to significantly more efficient inference on some specific models, there are only very recent and still quite restricted results that show the feasibility of lifted inference on certain syntactically defined classes of models. Lower complexity bounds that imply some limitations for the feasibility of lifted inference on more expressive model classes were established earlier in Jaeger (2000; Jaeger, M. 2000. On the complexity of inference about probabilistic relational models. Artificial Intelligence 117, 297–308). However, it is not immediate that these results also apply to the type of modeling languages that currently receive the most attention, i.e., weighted, quantifier-free formulas. In this paper we extend these earlier results, and show that under the assumption that NETIME≠ETIME, there is no polynomial lifted inference algorithm for knowledge bases of weighted, quantifier-, and function-free formulas. Further strengthening earlier results, this is also shown to hold for approximate inference and for knowledge bases not containing the equality predicate.
Actor-Networks in Music History: Clarifications and Critiques
Authors: PIEKUT BENJAMIN
Published: May 2014

This article offers clarifications and critiques of actor-network theory and its usefulness for music historiography. Reviewing the work of ANT theorists Bruno Latour, Annemarie Mol, and other social theorists (such as Georgina Born and Anna Tsing), the author explains that ANT is a methodology, not a theory. As a general introduction, the author outlines ANT's methodological presuppositions about human and non-human agency, action, ontology, and performance. He then examines how these methodological principles affect three concerns of music-historical interest: influence, genre, and context. In conclusion, he addresses problems related to temporality, critique, and reflexivity. He draws on music-historical examples after 1960: John Cage, the Jazz Composer's Guild, Henry Cow, Iggy Pop, and the Velvet Underground.
Formation of nuclear rings of barred galaxies and star formation therein
Authors: Kim Woong-Tae , Seo Woo-Young , Kim Yonghwi
Published: May 2014

Barred galaxies contain substructures such as a pair of dust lanes and nuclear rings, with the latter being sites of intense star formation. We study the substructure formation as well as star formation in nuclear rings using numerical simulations. We find that nuclear rings form not by the Lindblad resonances, as previously thought, but by the centrifugal barrier that inflowing gas along dust lanes cannot overcome. This predicts a smaller ring in a more strongly barred galaxy, consistent with observations. Star formation rate (SFR) in a nuclear ring is determined primarily by the mass inflow rate to the ring. In our models, the SFR typically shows a short strong burst associated with the rapid gas infall and stays very small for the rest of the evolution. When the SFR is low, ages of young star clusters exhibit an azimuthal gradient along the ring since star formation takes place mostly near the contact points between the dust lanes and the nuclear ring. When the SFR is large, on the other hand, star formation is widely distributed throughout the whole length of the ring, with no apparent age gradient of star clusters. Since observed ring star formation appears long-lived with episodic bursts, our results suggest that the bar region should be replenished continually with fresh gas from outside.
Molecules in the circumnuclear disk of the Galactic center
Authors: Harada Nanase , Riquelme Denise , Viti Serena , Menten Karl , Requena-Torres Miguel , Güsten Rolf , Hochgürtel Stefan
Published: May 2014

Within a few parsecs around the central black hole A*, chemistry in the dense molecular cloud material of the circumnuclear disk (CND) can be affected by many energetic phenomena such as high UV-flux from the massive central star cluster, X-rays from A*, shock waves, and an enhanced cosmic-ray flux. Recently, spectroscopic surveys with the IRAM 30 meter and the APEX 12 meter telescopes of substantial parts of the 80–500 GHz frequency range were made toward selected positions in and near the CND. These data sets contain lines from the molecules HCN, HCO+, HNC, CS, SO, SiO, CN, H2CO, HC3N, N2H+, H3O+ and others. We conduct Large Velocity Gradient analyses to obtain column densities and total hydrogen densities, n, for each species in molecular clouds located in the southwest lobe of the CND. The data for the above mentioned molecules indicate 105 cm−3 ≲ n < 106 cm−3, which shows that the CND is tidally unstable. The derived chemical composition is compared with a chemical model calculated using the UCL_CHEM code that includes gas and grain reactions, and the effects of shock waves. Models are run for varying shock velocities, cosmic-ray ionization rates, and number densities. The resulting chemical composition is fitted best to an extremely high value of cosmic-ray ionization rate ζ ∼ 10−14 s−1, 3 orders of magnitude higher than the value in regular Galactic molecular clouds, if the pre-shock density is n=105 cm−3.
GBT and VLA investigation of the ionized gas towards the Galactic center
Authors: Royster M. J. , Yusef-Zadeh F.
Published: May 2014

We report results of a study of the ionized gas towards the Galactic center with radio recombination lines at cm wavelengths. Both the Green Bank Telescope and the Very Large Array were utilized to probe the kinematics of the ionized gas on a global scale for both diffuse and discrete sources within the inner 2.0° × 0.5° (l × b). A diffuse ∼0 km s−1 gas, a thermal flux continuum fraction exceeding 40%, and an asymmetry where ∼70% of the ionized gas is found at positive Galactic longitudes are the preliminary results briefly discussed here.
Hydroxyl, water, ammonia, carbon monoxide and neutral carbon towards the Sgr A complex
Authors: Karlsson R. , Sandqvist Aa. , Hjalmarson Å. , Winnberg A. , Fathi K. , Frisk U. , Olberg M.
Published: May 2014

We observed Hydroxyl, water, ammonia, carbon monoxide and neutral carbon towards the +50 km s−1 cloud (M−0.02−0.07), the circumnuclear disk (CND) and the +20 km s−1 (M−0.13−0.08) cloud in the Sgr A complex with the VLA, Odin and SEST. Strong OH absorption, H2O emission and absorption lines were seen at all three positions. Strong C18O emissions were seen towards the +50 and +20 km s−1 clouds. The CND is rich in H2O and OH, and these abundances are considerably higher than in the surrounding clouds, indicating that shocks, star formation and clump collisions prevail in those objects. A comparison with the literature reveals that it is likely that PDR chemistry including grain surface reactions, and perhaps also the influences of shocks has led to the observed abundances of the observed molecular species studied here. In the redward high-velocity line wings of both the +50 and +20 km s−1 clouds and the CND, the very high H2O abundances are suggested to be caused by the combined action of shock desorption from icy grain mantles and high-temperature, gas-phase shock chemistry. Only three of the molecules are briefly discussed here. For OH and H2O three of the nine observed positions are shown, while a map of the C18O emission is provided. An extensive paper was recently published with Open Access (Karlsson et al. 2013, A&A 554, A141).
Shock structure and shock heating in the Galactic central molecular zone
Authors: Ott Jürgen , Burton Michael , Jones Paul , Meier David S.
Published: May 2014

We present maps of a large number of dense molecular gas tracers across the central molecular zone of our Galaxy. The data were taken with the CSIRO/CASS Mopra telescope in Large Projects in the 1.3 cm, 7 mm, and 3 mm wavelength regimes. Here, we focus on the brightness of the shock tracers SiO and HNCO, molecules that are liberated from dust grains under strong (SiO) and weak (HNCO) shocks. The shocks may have occurred when the gas enters the bar regions and the shock differences could be due to differences in the moving cloud masses. Based on tracers of ionizing photons, it is unlikely that the morphological differences are due to selective photo-dissociation of the molecules. We also observe direct heating of molecular gas in strongly shocked zones, with high SiO/HNCO ratios, where temperatures are determined from the transitions of ammonia. Strong shocks appear to be the most efficient heating source of molecular gas, apart from high energy emission emitted by the central supermassive black hole Sgr A* and the processes within the extreme star formation region Sgr B2.
Unbiased line surveys of molecular clouds in the Galactic center region
Authors: Riquelme D. , Aladro R. , Martín S. , Requena-Torres M. , Martín-Pintado J. , Güsten R. , Mauersberger R. , Harada N. , Hochgürtel S. , Menten K. M.
Published: May 2014

Using the IRAM 30 m telescope, we perform a molecular line survey of the 3 and 2 mm wavelength ranges towards 5 selected positions in the Galactic center region, sampling shocked regions, ultraviolet (UV) and X-ray pervaded regions, and positions with rich organic chemistry. These surveys have the potential to be used as chemical templates for different types of activity, such as photodissociated regions (PDRs), shocks and X-ray dominated regions (XDRs). Complementary, molecular surveys done towards extragalactic nuclei, that are also dominated by these physical activities, were carried by our group.
Oxygen isotope ratio studies in the Galactic center region
Authors: Zhang JiangShui , Sun Lulu , Qiu Jianjie , Lu Dengrong , Wang Min
Published: May 2014

Using the Delingha 13.7 m telescope with a 9-beam SIS superconducting receiver installed, we carried out mapping of C18O and C17O J = (1 − 0) toward molecular clouds in the central molecular zone (CMZ) and in the halo of our galaxy. From the integrated intensity ratio of C18O to C17O, the isotope ratio 18O/17O ratio can be estimated, which is considered to be one of the most useful tracers of nuclear processing and metal enrichment. Here preliminary results are presented toward Sgr A, Sgr B2, Sgr C, Sgr D, and the 1.°3 complex in the CMZ and M+5.3–0.3 in the halo.
A new very faint X-ray transient in the Galactic center
Authors: Soldi Simona , Clavel Maïca , Goldwurm Andrea , Ponti Gabriele , Terrier Régis , Trap Guillaume , Greiner Jochen , Prinz Tobias , Rau Arne , Servillat Mathieu
Published: May 2014

A new X-ray transient, XMMU J174505.3-291445, has been detected within the 2012 XMM-Newton scan of the Galactic center. The short 4.7 ks flare, the highly absorbed X-ray spectrum and the relatively low luminosity of the event suggest the association of the source with either the class of very faint X-ray transients or that of supergiant fast X-ray transients. Further analysis, together with the identification of the possible infrared counterpart will help to unveil the true nature of XMMU J174505.3-291445.
A new MIR bow shock source in the Galactic center
Authors: Sabha N. , Zamaninasab M. , Eckart A. , Moser L.
Published: May 2014

We find a convex-like feature at a distance of 0.68 pc (17″) from the position of the supermassive black hole, Sgr A*, at the center of the nuclear stellar cluster. This feature resembles a stellar bow shock with a symmetry axis pointing to the center. We discuss the possible nature of the feature and the implications of its alignment with other dusty comet-like objects inside the central parsec.
Kinematics and dynamics of molecular gas in galactic centers
Authors: Sakamoto K.
Published: May 2014

The central molecular zone (CMZ) in the central half kpc of the Milky Way is a massive concentration of molecular gas in the center of a barred spiral galaxy. Current and past activities in the Galactic center include the formation of massive stars/clusters, AGN feeding, and feedback. At the same time, observations of molecular gas in external galaxies show that many disk galaxies have similar condensations of molecular gas in their central kpc or so. They also have CMZs, or nuclear molecular rings or concentrations in more common terms among extragalactic observers. The formation of the CMZs are often, but not always, related to stellar bars. The centers of nearby galaxies can provide valuable information on the general properties of galactic centers and CMZs through comparative studies of multiple galactic centers of different characteristics from various viewing angles. Linear resolutions achieved toward nearby extragalactic CMZs with modern radio interferometers are now comparable to those achieved toward the Galactic CMZ with small single-dish telescopes. I review and present work on the formation mechanism and properties of the CMZs in external galaxies with some comparisons with the CMZ of our Galaxy.
MALT90: tracing the chemistry and kinematics of molecular clumps within the central molecular zone
Authors: Contreras Y. , Rathborne J. , Jackson J. , Foster J. , Longmore S. ,   the MALT90 team
Published: May 2014

The MALT90 survey targets more than 2000 high-mass star-forming clumps in the Galactic plane obtaining small maps around each of them, in 16 molecular lines at 90 GHz. By observing several thousand high-mass star forming clumps MALT90 aims to characterize their global chemical and physical evolution. Here we summarize the survey parameters and show examples of the MALT90 data toward three clumps in the central molecular zone.
An overview of the PAHTAT toolbox
Authors: Pilleri P. , Joblin C. , Berné O. , Montillaud J. , Okada Y.
Published: May 2014

In this contribution, we briefly describe how an observed mid-infrared (5.5-14 μm) spectrum can be used to trace key physical conditions along a given line of sight, such as the UV radiation field, the ionization parameter and the dust column density. These parameters are often difficult to determine independently from PDR models. The PAHTAT toolbox offers the opportunity to analyze mid-IR spectra using a limited number of parameters, that are associated with the physical properties of the dust and gas being observed.
Dynamical evolution of dense star clusters in galactic nuclei
Authors: Haas Jaroslav , Šubr Ladislav
Published: May 2014

By means of direct numerical N-body modeling, we investigate the orbital evolution of an initially thin, central mass dominated stellar disk. We include the perturbative gravitational influence of an extended spherically symmetric star cluster and the mutual gravitational interaction of the stars within the disk. Our results show that the two-body relaxation of the disk leads to significant changes of its radial density profile. In particular, the disk naturally evolves, for a variety of initial configurations, a similar broken power-law surface density profile. Hence, it appears that the single power-law surface density profile ∝R−2 suggested by various authors to describe the young stellar disk observed in the Sgr A* region does not match theoretical expectations.
The Keplerian orbit of G2
Authors: Meyer L. , Ghez A. M. , Witzel G. , Do T. , Phifer K. , Sitarski B. N. , Morris M. R. , Boehle A. , Yelda S. , Lu J. R. , Becklin E.
Published: May 2014

We give an update of the observations and analysis of G2 – the gaseous red emission-line object that is on a very eccentric orbit around the Galaxy's central black hole and predicted to come within 2400 RS in early 2014. During 2013, the laser guide star adaptive optics systems on the W. M. Keck I and II telescopes were used to obtain three epochs of spectroscopy and imaging at the highest spatial resolution currently possible in the near-IR. The updated orbital solution derived from radial velocities in addition to Br-γ line astrometry is consistent with our earlier estimates. Strikingly, even ∼ 6 months before pericenter passage there is no perceptible deviation from a Keplerian orbit. We furthermore show that a proposed “tail” of G2 is likely not associated with it but is rather an independent gas structure. We also show that G2 does not seem to be unique, since several red emission-line objects can be found in the central arcsecond. Taken together, it seems more likely that G2 is ultimately stellar in nature, although there is clearly gas associated with it.
Near infrared variability of Sgr A* - spectral index measurements
Authors: Witzel G. , Morris M. , Ghez A. , Meyer L. , Becklin E. , Matthews K. , Lu J. R. , Do T. , Campbell R.
Published: May 2014

We discuss observations of Sagittarius A* with NACO@VLT in K-band and recent synchronous observations with NIRC2@Keck II and OSIRIS@Keck I in L′-band and H-band, respectively. The variability of Sagittarius A* in the near infrared is a continuous one-state process that can be described by a pure red-noise process having a timescale of a few hours. We describe this process and its properties in detail. Our newest observations with the Keck telescopes represent the first truly synchronous high cadence data set to test for time variability of the spectral index within the near infrared. We discovered a time-variable spectral index that might be interpreted as a time lag of the L′-band with respect to the H-band.
Exploring plasma evolution during Sagittarius A* flares
Authors: Dibi S. , Markoff S. , Belmont R. , Malzac J. , Barrière N. M. , Tomsick J. A.
Published: May 2014

We present a new way of describing the flares occurring from Sgr A* within a single zone with a self-consistent calculation of the particle distribution. The results allow us to give an interpretation to the flaring events generated very close to the supermassive black hole (SMBH) without assuming a specific particle distribution. We conclude that the flare data are more likely generated by a weakly magnetized plasma in which the particles flow in and out as expected from an accretion flow. Such a plasma, with prescription for non-thermal acceleration, injection, escape, and cooling losses, gives a spectrum with a break between the infra-red and the X-ray, allowing a better simultaneous match in the different wavelengths. The parameters favor the non-thermal synchrotron spectrum, and a decrease/increase of the magnetic field and plasma density are not favored for producing the flare event, but particle acceleration must be happening by other means. We show that under certain conditions, the real particle distribution can differ significantly from the standard distributions used in such studies.
Theory of G2 cloud multi-wavelength emission
Authors: Shcherbakov R. V.
Published: May 2014

An object called G2 was recently discovered moving towards the supermassive black hole in the Galactic center. G2 emits infrared (IR) lines and continuum, which allows constraining its properties. The question is still unresolved whether G2 has a central windy star or it is a coreless cloud. Assuming the object is a cloud originating near the apocenter I perform line/continuum IR diagnostics, revisit estimates of non-thermal emission from pericenter passage, and speculate about future observational prospects. This work is partially reported in Shcherbakov (2013) and partially consists of new ideas discussed at the conference.