First detection of CF+ towards a high-mass protostar

We report the first detection of the J = 1 - 0 (102.6 GHz) rotational lines of CF+ (fluoromethylidynium ion) towards CygX-N63, a young and massive protostar of the Cygnus X region. This detection occurred as part of an unbiased spectral survey of this object in the 0.8-3 mm range, performed with the IRAM 30m telescope. The data were analyzed using a local thermodynamical equilibrium model (LTE model) and a population diagram in order to derive the column density. The line velocity (-4 km s-1) and line width (1.6 km s-1) indicate an origin from the collapsing envelope of the protostar. We obtain a CF+ column density of 4.10e11 cm-2. The CF+ ion is thought to be a good tracer for C+ and assuming a ratio of 10e-6 for CF+/C+, we derive a total number of C+ of 1.2x10e53 within the beam. There is no evidence of carbon ionization caused by an exterior source of UV photons suggesting that the protostar itself is the source of ionization. Ionization from the protostellar photosphere is not efficient enough. In contrast, X-ray ionization from the accretion shock(s) and UV ionization from outflow shocks could provide a large enough ionizing power to explain our CF+ detection. Surprisingly, CF+ has been detected towards a cold, massive protostar with no sign of an external photon dissociation region (PDR), which means that the only possibility is the existence of a significant inner source of C+. This is an important result that opens interesting perspectives to study the early development of ionized regions and to approach the issue of the evolution of the inner regions of collapsing envelopes of massive protostars. The existence of high energy radiations early in the evolution of massive protostars also has important implications for chemical evolution of dense collapsing gas and could trigger peculiar chemistry and early formation of a hot core.Comment: 6 page

Multiscale Partition of Unity

We introduce a new Partition of Unity Method for the numerical homogenization of elliptic partial differential equations with arbitrarily rough coefficients. We do not restrict to a particular ansatz space or the existence of a finite element mesh. The method modifies a given partition of unity such that optimal convergence is achieved independent of oscillation or discontinuities of the diffusion coefficient. The modification is based on an orthogonal decomposition of the solution space while preserving the partition of unity property. This precomputation involves the solution of independent problems on local subdomains of selectable size. We deduce quantitative error estimates for the method that account for the chosen amount of localization. Numerical experiments illustrate the high approximation properties even for 'cheap' parameter choices.Comment: Proceedings for Seventh International Workshop on Meshfree Methods for Partial Differential Equations, 18 pages, 3 figure

A unification in the theory of linearization of second order nonlinear ordinary differential equations

In this letter, we introduce a new generalized linearizing transformation (GLT) for second order nonlinear ordinary differential equations (SNODEs). The well known invertible point (IPT) and non-point transformations (NPT) can be derived as sub-cases of the GLT. A wider class of nonlinear ODEs that cannot be linearized through NPT and IPT can be linearized by this GLT. We also illustrate how to construct GLTs and to identify the form of the linearizable equations and propose a procedure to derive the general solution from this GLT for the SNODEs. We demonstrate the theory with two examples which are of contemporary interest.Comment: 8 page

Autoimmunity Overlaps Primary Biliary Cirrhosis: a Not Straightforward Diagnosis

info:eu-repo/semantics/publishedVersio

Tolerance of cucumber crop to salinity in greenhouse

Neste trabalho se objetivou avaliar a cultura do pepino conduzido sobre condição salina, proveniente de sais fertilizantes, com seis níveis de salinidade do solo (1,5; 2,5; 3,5; 4,5; 5,5 e 6,5 dS m-1). O experimento foi conduzido na área experimental do Departamento de Engenharia Rural da ESALQ/USP, Piracicaba, SP. O plantio foi realizado em vasos utilizando-se solo arenoso. A época de plantio foi de 28/08/07 a 20/10/07. Como principais resultados, verificou-se que a produtividade máxima obtida foi 2,45 kg m-2 para o nível de salinidade 3,5 dS m-1; com os valores de produção relativa obteve-se a salinidade limiar (SL) de 4,08 dS m-1, com uma queda de produção, após o ponto limiar na ordem de 19,33% por dS m-1, para cada aumento de uma unidade de salinidade do solo.The objective of this work was to evaluate the cucumber crop in saline conditions resulting from fertilizer salt, under six levels of soil salinity (1.5, 2.5, 3.5, 4.5, 5.5 and 6.5 dS m-1). The study was carried out in the experimental area of the Department of Rural Engineering of the ESALQ/USP, Piracicaba/SP, Brazil. The planting was carried out in recipients using sandy soil during the period of 28/08/07 to 20/10/07. As the main results, it was verified that the maximum productivity was 2.45 kg m-2 for the salinity level of 3.5 dS m-1, that with the values of relative production the threshold salinity (SL) observed was of 4.08 dS m-1, and that there was a decline of 19.33% in production for unit increase of soil salinity above the threshold point

On a generalised model for time-dependent variance with long-term memory

The ARCH process (R. F. Engle, 1982) constitutes a paradigmatic generator of stochastic time series with time-dependent variance like it appears on a wide broad of systems besides economics in which ARCH was born. Although the ARCH process captures the so-called "volatility clustering" and the asymptotic power-law probability density distribution of the random variable, it is not capable to reproduce further statistical properties of many of these time series such as: the strong persistence of the instantaneous variance characterised by large values of the Hurst exponent (H > 0.8), and asymptotic power-law decay of the absolute values self-correlation function. By means of considering an effective return obtained from a correlation of past returns that has a q-exponential form we are able to fix the limitations of the original model. Moreover, this improvement can be obtained through the correct choice of a sole additional parameter, $q_{m}$. The assessment of its validity and usefulness is made by mimicking daily fluctuations of SP500 financial index.Comment: 6 pages, 4 figure

The W43-MM1 mini-starburst ridge, a test for star formation efficiency models

Context: Star formation efficiency (SFE) theories are currently based on statistical distributions of turbulent cloud structures and a simple model of star formation from cores. They remain poorly tested, especially at the highest densities. Aims: We investigate the effects of gas density on the SFE through measurements of the core formation efficiency (CFE). With a total mass of $\sim2\times10^4$ M$_\odot$, the W43-MM1 ridge is one of the most convincing candidate precursor of starburst clusters and thus one of the best place to investigate star formation. Methods: We used high-angular resolution maps obtained at 3 mm and 1 mm within W43-MM1 with the IRAM Plateau de Bure Interferometer to reveal a cluster of 11 massive dense cores (MDCs), and, one of the most massive protostellar cores known. An Herschel column density image provided the mass distribution of the cloud gas. We then measured the 'instantaneous' CFE and estimated the SFE and the star formation rate (SFR) within subregions of the W43-MM1 ridge. Results: The high SFE found in the ridge ($\sim$6% enclosed in $\sim$8 pc$^3$) confirms its ability to form a starburst cluster. There is however a clear lack of dense cores in the northern part of the ridge, which may be currently assembling. The CFE and the SFE are observed to increase with volume gas density while the SFR steeply decreases with the virial parameter, $\alpha_{vir}$. Statistical models of the SFR may well describe the outskirts of the W43-MM1 ridge but struggle to reproduce its inner part, which corresponds to measurements at low $\alpha_{vir}$. It may be that ridges do not follow the log-normal density distribution, Larson relations, and stationary conditions forced in the statistical SFR models.Comment: 13 pages, 7 figures. Accepted by A&

How managerial coaching promotes employees' affective commitment and individual performance

Abstract Purpose: This study sought to provide a more comprehensive understanding of how managers’ coaching skills can affect individual performance through the mediating role of affective commitment. Design/methodology/approach: The sample included 198 employees from diverse organizations. Based on an online survey, respondents assessed their managers’ coaching skills and reported their own individual performance and affective commitment to their organization. Findings: The findings show that managers’ coaching skills have a positive impact on individual performance and affective commitment, with the latter mediating the relationship between the first two variables. Research limitations/implications: Additional studies with larger samples are needed to understand more fully not only the impact of managers’ coaching skills on individual performance but also other psychosocial variables affecting that relationship. Practical implications: Organizations can increase employees’ affective commitment and individual performance by encouraging managers to integrate more coaching skills into their leadership styles. Originality/value: This study is the first to integrate managers’ coaching skills, affective commitment, and individual performance into a single research model, thereby extending previous research on this topic.info:eu-repo/semantics/publishedVersio

Herbivory drives kelp recruits into ‘hiding’ in a warm ocean climate

Assessing effects of herbivory across broad gradients of varying ocean climate conditions and over small spatial scales is crucial for understand- ing its influence on primary producers. Effects of her- bivory on the distribution and abundance of kelp re- cruits were examined experimentally at two regions under contrasting ocean climate. Specifically, the abundance and survivorship of kelp recruits and the abundance of macro-herbivores were compared be- tween a ‘cool’ and a ‘warm’ region in northern and central Portugal, respectively. In each region, the abundance of kelp recruits and the intensity of grazing were compared between habitats of different topography within reefs (open reef vs. crevices). Com- pared to the ‘warm’ region, the abundance of kelp re- cruits was 3.9 times greater in the ‘cool’ region, where 85% of recruits were found in open reef habitats. In contrast, 87% of recruits in the ‘warm’ region were re- stricted to crevices. The ‘warm’ region had 140 times greater abundances of sea urchins, 45 times more herbivorous fish and 4.1 times more grazing marks on kelp recruits than the ‘cool’ region. Grazing assays showed ca. 50 times higher rates of kelp biomass con- sumption, mainly by fishes, and zero survivorship of kelp recruits in the ‘warm’ relative to the ‘cool’ region. This study suggests both temperature and herbivores affect abundances of kelp recruits across latitudes, and demonstrates how herbivores affect their distri- bution at local scales, driving kelp recruits into ‘hiding’ in crevices under intense herbivory. Conse- quently, where net recruitment success is compro- mised by herbivory, the persistence of kelps will be contingent on availability of topographical refuges