A new intermediate mass protostar in the Cepheus A HW2 region

We present the discovery of the first molecular hot core associated with an intermediate mass protostar in the CepA HW2 region. The hot condensation was detected from single dish and interferometric observations of several high excitation rotational lines (from 100 to 880K above the ground state) of SO2 in the ground vibrational state and of HC3N in the vibrationally excited states v7=1 and v7=2. The kinetic temperature derived from both molecules is 160K. The high-angular resolution observations (1.25'' x 0.99'') of the SO2 J=28(7,21)-29(6,24) line (488K above the ground state) show that the hot gas is concentrated in a compact condensation with a size of 0.6''(430AU), located 0.4'' (300AU) east from the radio-jet HW2. The total SO2 column density in the hot condensation is 10E18cm-2, with a H2 column density ranging from 10E23 to 6 x 10E24cm-2. The H2 density and the SO2 fractional abundance must be larger than 10E7cm-3 and 2 x 10E-7 respectively. The most likely alternatives for the nature of the hot and very dense condensation are discussed. From the large column densities of hot gas, the detection of the HC3N vibrationally excited lines and the large SO2 abundance, we favor the interpretation of a hot core heated by an intermediate mass protostar of 10E3 Lo. This indicates that the CepA HW2 region contains a cluster of very young stars

Tell me your age and I tell you what you trust: the moderating effect of generations

Purpose: The proliferation of social commerce websites has allowed consumers to share and exchange information, experiences, advice and opinions. Recently, information provided by users has been considered more trustworthy than the information shared by companies. However, the way in which users interact with technology can vary with age, and generational cohorts show different shopping behaviors, interests and attitudes. Hence, the way users process information (user-generated vs company-generated) can affect trust differently. Drawing on the trust transfer theory and the generational cohort theory, the purpose of this paper is to analyze the effects on user- and company-generated information in boosting trust of three different cohorts (Generation X, Y and Z). Design/methodology/approach: The data were collected through an online survey. The sample comprised 715 users of social commerce websites, aged between 16 and 55 years old. The study was analyzed using partial least squares with the statistical software Smart PLS 3. Findings: The empirical results show that generational cohorts show different patterns. Generation X transfers trust to social commerce websites mainly from trust in information generated by companies, while Generation Z transfers trust mainly from information generated by users. Finally, Generation Y, in contrast to previous findings about millennials, develops trust based on company-generated information to an even greater extent than does Generation X. Originality/value: The originality of this study lies in its analysis of generational differences when it comes to trusting one type of information over another. This study contributes to the idea that users cannot be considered as a whole but must be segmented into generational cohorts

Social commerce users'' optimal experience: stimuli, response and culture

Social commerce users' experience is generated during socio-commercial interactions. Therein, users receive utilitarian and hedonic stimuli that form their experience and influence their responses. However, research is needed to understand how this experience is generated. Based on the stimulus-organism-response framework and flow theory, this study analyzes how hedonic stimulus (here called sPassion) and utilitarian stimulus (usability) affect users' flow experience (organism) to positively impact emotional and behavioral loyalty (users' responses). Furthermore, as social commerce users are culturally diverse, the moderating effect of cultural background is studied, drawing on Hofstede's cultural dimensions. Findings show that hedonic stimulus more strongly impacts social commerce users' flow experience versus utilitarian stimulus. Once users reach the state of optimal experience, their positive responses are reflected in their increased intention to spread social word of mouth, to return to the website and to repurchase on it. Additionally, optimal user experience in social commerce is generated mainly through hedonic stimuli and, while social commerce environments can be culturally diverse, cultural background does not imply changes in users' behavioral patterns. This study theoretically advances research on social commerce users' experience. Likewise, the findings guide online retailers in optimizing user experience via hedonic stimuli to enhance loyalty

From sPassion to sWOM: The role of flow

Purpose - Social commerce websites entail a completely new scenario for sharing experiences and opinions due to its richness in terms of social interactions. Nowadays, users can interact with the company and with other users; hence, it seems important to study how social stimuli affect users. Drawing on the stimulus-organism-response framework and flow theory, the purpose of this paper is to propose that the social stimulus (named social passion (sPassion)) has a positive effect on the organism (state of flow), which leads to a users' positive response (via social word of mouth (sWOM)). Design/methodology/approach - The data were collected through an online survey in 2015. The sample consists of 771 users of social commerce websites, of which 51 percent are male and 49 percent female, aged between 16 and 80 years old. Structural equation modeling was used to analyze the data with the statistical software SPSS version 22 and EQS 6. Findings - The empirical results confirm that passionate users are prone to experience a state of flow and, as a consequence, share positive sWOM. Originality/value - This study contributes to the literature on customers' online participation, and the findings are hoped to help companies in developing social commerce websites that boost users' exchange of information

Single-point velocity distribution in turbulence

We show that the tails of the single-point velocity probability distribution function (PDF) are generally non-Gaussian in developed turbulence. By using instanton formalism for the Navier-Stokes equation, we establish the relation between the PDF tails of the velocity and those of the external forcing. In particular, we show that a Gaussian random force having correlation scale $L$ and correlation time $\tau$ produces velocity PDF tails $\ln{\cal P}(v)\propto-v^4$ at $v\gg v_{rms}, L/\tau$. For a short-correlated forcing when $\tau\ll L/v_{rms}$ there is an intermediate asymptotics $\ln {\cal P}(v)\propto-v^3$ at $L/\tau\gg v\gg v_{rms}$.Comment: 9 pages, revtex, no figure

Treatment of a Complex Distal Triceps Tendon Rupture With a New Technique: A Case Report

Introduction: The distal triceps tendon rupture is an uncommon injury. The acute treatment is well-defined, but when a delayed diagnosis is made or when a tendon retraction is present the alternatives or reconstruction are limited and sometimes complex. Case Presentation: In this case, we report on a 28-year-old man who presented with a chronic disruption of the distal triceps tendon with a gap of approximately 15 cm. The patient was diagnosed in another center with an inveterate breakage of the distal triceps tendon and was initially treated with an Achilles allograft that was complicated by a wound infection and required more than ten surgeries. Nearly 22 months after the initial trauma, and 12 months after the first surgery, we performed a reconstruction with an Achilles tendon allograft using the new technique of distal attachment. At the 12-month follow-up the patient presented a joint balance from -5º to 110º and presented with no pain. Conclusions: The use of an Achilles tendon allograft provides excellent results in complex distal triceps tendon ruptures. We report the use of a new technique to anchor a distal Achilles allograft

W boson production at hadron colliders: the lepton charge asymmetry in NNLO QCD

We consider the production of W bosons in hadron collisions, and the subsequent leptonic decay W->lnu_l. We study the asymmetry between the rapidity distributions of the charged leptons, and we present its computation up to the next-to-next-to-leading order (NNLO) in QCD perturbation theory. Our calculation includes the dependence on the lepton kinematical cuts that are necessarily applied to select W-> lnu_l events in actual experimental analyses at hadron colliders. We illustrate the main differences between the W and lepton charge asymmetry, and we discuss their physical origin and the effect of the QCD radiative corrections. We show detailed numerical results on the charge asymmetry in ppbar collisions at the Tevatron, and we discuss the comparison with some of the available data. Some illustrative results on the lepton charge asymmetry in pp collisions at LHC energies are presented.Comment: 37 pages, 21 figure

The treatment of the infrared region in perturbative QCD

We discuss the contribution coming from the infrared region to NLO matrix elements and/or coefficient functions of hard QCD processes. Strictly speaking, this contribution is not known theoretically, since it is beyond perturbative QCD. For DGLAP evolution all the infrared contributions are collected in the phenomenological input parton distribution functions (PDFs), at some relatively low scale Q_0; functions which are obtained from a fit to the `global' data. However dimensional regularization sometimes produces a non-zero result coming from the infrared region. Instead of this conventional regularization treatment, we argue that the proper procedure is to first subtract from the NLO matrix element the contribution already generated at the same order in \alpha_s by the LO DGLAP splitting function convoluted with the LO matrix element. This prescription eliminates the logarithmic infrared divergence, giving a well-defined result which is consistent with the original idea that everything below Q_0 is collected in the PDF input. We quantify the difference between the proposed treatment and the conventional approach using low-mass Drell-Yan production and deep inelastic electron-proton scattering as examples; and discuss the potential impact on the `global' PDF analyses. We present arguments to show that the difference cannot be regarded as simply the use of an alternative factorization scheme.Comment: 15 pages, 5 figures, title changed, text considerably modified to improve presentation, and discussion section enlarge

Relating hygroscopicity and composition of organic aerosol particulate matter

A hygroscopicity tandem differential mobility analyzer (HTDMA) was used to measure the water uptake (hygroscopicity) of secondary organic aerosol (SOA) formed during the chemical and photochemical oxidation of several organic precursors in a smog chamber. Electron ionization mass spectra of the non-refractory submicron aerosol were simultaneously determined with an aerosol mass spectrometer (AMS), and correlations between the two different signals were investigated. SOA hygroscopicity was found to strongly correlate with the relative abundance of the ion signal m/z 44 expressed as a fraction of total organic signal (f44). m/z 44 is due mostly to the ion fragment CO2+ for all types of SOA systems studied, and has been previously shown to strongly correlate with organic O/C for ambient and chamber OA. The analysis was also performed on ambient OA from two field experiments at the remote site Jungfraujoch, and the megacity Mexico City, where similar results were found. A simple empirical linear relation between the hygroscopicity of OA at subsaturated RH, as given by the hygroscopic growth factor (GF) or "κorg" parameter, and f44 was determined and is given by κorg=2.2×f44−0.13. This approximation can be further verified and refined as the database for AMS and HTDMA measurements is constantly being expanded around the world. The use of this approximation could introduce an important simplification in the parameterization of hygroscopicity of OA in atmospheric models, since f44 is correlated with the photochemical age of an air mass

Relating hygroscopicity and composition of organic aerosol particulate matter

A hygroscopicity tandem differential mobility analyzer (HTDMA) was used to measure the water uptake (hygroscopicity) of secondary organic aerosol (SOA) formed during the chemical and photochemical oxidation of several organic precursors in a smog chamber. Electron ionization mass spectra of the non-refractory submicron aerosol were simultaneously determined with an aerosol mass spectrometer (AMS), and correlations between the two different signals were investigated. SOA hygroscopicity was found to strongly correlate with the relative abundance of the ion signal m/z 44 expressed as a fraction of total organic signal (f44). m/z 44 is due mostly to the ion fragment CO2+ for all types of SOA systems studied, and has been previously shown to strongly correlate with organic O/C for ambient and chamber OA. The analysis was also performed on ambient OA from two field experiments at the remote site Jungfraujoch, and the megacity Mexico City, where similar results were found. A simple empirical linear relation between the hygroscopicity of OA at subsaturated RH, as given by the hygroscopic growth factor (GF) or "ϰorg" parameter, and f44 was determined and is given by ϰorg = 2.2 × f44 − 0.13. This approximation can be further verified and refined as the database for AMS and HTDMA measurements is constantly being expanded around the world. The use of this approximation could introduce an important simplification in the parameterization of hygroscopicity of OA in atmospheric models, since f44 is correlated with the photochemical age of an air mass