Qualitative Research: A Grounded Theory Example and Evaluation Criteria

The qualitative research paradigm, although occasionally applied, is not widely discussed in agribusiness and agricultural economics literature. The primary goals of this paper are (a) to present insights into qualitative research approaches and processes by outlining grounded theory as an example of a systematic and rigorous qualitative approach, and (b) to discuss criteria for scientific rigor applicable to qualitative research. In addition, assessing qualitative research is demonstrated by using a published example.management research, methodology, qualitative research methods, reliability, validity, Research Methods/ Statistical Methods,

EMPLOYEE RETENTION: COMPONENTS OF JOB SATISFACTION OF GREEN INDUSTRY EMPLOYEES

Fourteen businesses participated in case studies of labor management practices. Fifteen non-supervisory employee interviews were analyzed regarding components of job satisfaction. Components were family values, achievement, recognition, work itself, involvement, personal life, interpersonal relationships, job security, supervision, working conditions, organization, safety, compensation and information.Labor and Human Capital,

Planet population synthesis driven by pebble accretion in cluster environments

The evolution of protoplanetary discs embedded in stellar clusters depends on the age and the stellar density in which they are embedded. Stellar clusters of young age and high stellar surface density destroy protoplanetary discs by external photoevaporation and stellar encounters. Here we consider the effect of background heating from newly formed stellar clusters on the structure of protoplanetary discs and how it affects the formation of planets in these discs. Our planet formation model is build on the core accretion scenario including pebble accretion. We synthesize planet populations that we compare to observations. The giant planets in our simulations migrate over large distances due to the fast type-II migration regime induced by a high disc viscosity ($\alpha=5.4 \times 10^{-3}$). Cold Jupiters (r>1 AU) originate preferably from the outer disc, while hot Jupiters (r<0.1 AU) preferably form in the inner disc. We find that the formation of gas giants via pebble accretion is in agreement with the metallicity correlation, meaning that more gas giants are formed at larger metallicity. However, our synthetic population of isolated stars host a significant amount of giant planets even at low metallicity, in contradiction to observations where giant planets are preferably found around high metallicity stars, indicating that pebble accretion is very efficient in the standard pebble accretion framework. On the other hand, discs around stars embedded in cluster environments hardly form any giant planets at low metallicity in agreement with observations, where these changes originate from the increased temperature in the outer parts of the disc, which prolongs the core accretion time-scale of the planet. We therefore conclude that the outer disc structure and the planet's formation location determines the giant planet occurrence rate and the formation efficiency of cold and hot Jupiters.Comment: 12 pages, accepted for publication in MNRA

Planet migration in three-dimensional radiative discs

The migration of growing protoplanets depends on the thermodynamics of the ambient disc. Standard modelling, using locally isothermal discs, indicate in the low planet mass regime an inward (type-I) migration. Taking into account non-isothermal effects, recent studies have shown that the direction of the type-I migration can change from inward to outward. In this paper we extend previous two-dimensional studies, and investigate the planet-disc interaction in viscous, radiative discs using fully three-dimensional radiation hydrodynamical simulations of protoplanetary accretion discs with embedded planets, for a range of planetary masses. We use an explicit three-dimensional (3D) hydrodynamical code NIRVANA that includes full tensor viscosity. We have added implicit radiation transport in the flux-limited diffusion approximation, and to speed up the simulations significantly we have newly adapted and implemented the FARGO-algorithm in a 3D context. First, we present results of test simulations that demonstrate the accuracy of the newly implemented FARGO-method in 3D. For a planet mass of 20 M_earth we then show that the inclusion of radiative effects yields a torque reversal also in full 3D. For the same opacity law used the effect is even stronger in 3D than in the corresponding 2D simulations, due to a slightly thinner disc. Finally, we demonstrate the extent of the torque reversal by calculating a sequence of planet masses. Through full 3D simulations of embedded planets in viscous, radiative discs we confirm that the migration can be directed outwards up to planet masses of about 33 M_earth. Hence, the effect may help to resolve the problem of too rapid inward migration of planets during their type-I phase.Comment: 16 pages, Astronomy&Astrophysics, in pres

Pork Managers' Perception of Labor Management Practices and Their Risks

Although managing labor has become important for farm operations success, training and education for farm managers focuses on agricultural production management and few studies provide an empirical basis on how agricultural labor management differs from labor management in other industries. With the exception of Hurley et al., little is known about labor management practices in pork production, specifically. This study used the focus group discussion method with four focus group meetings in Michigan and two in Kansas in 2006. The average group size was four participants. All group discussions were tape-recorded and transcribed. The ATLAS-TI software was used to support the data analysis. Labor management topics discussed were as follows (order based on the amount of discussion dedicated to each topic): (1) performance management, (2) compensation, (3) recruitment, (4) training, (5) working conditions and organizational structure of farms, (6) selection, (7) hiring immigrant employees, (8) discipline, (9) performance evaluation, (10) social environment, and (11) labor law. Labor management practices, labor attributes, and work characteristics were analyzed within each category and characterized as risk reducing or risk increasing, according to managers perceptions. An educational pilot workshop was developed based on the focus group discussions and delivered in both Michigan and Kansas. Topics covered in the workshops included recruitment and selection, training, employee evaluation, compensation, conflict management, discipline and termination, communication, and motivation. Workshops were evaluated both immediately afterwards, through written anonymous workshop evaluations and through phone interviews. While most participants were able to point to specific content learned and had started to implement changes, hoping to increase productivity and/or reduce costs, few were able to quantify the monetary value of those changes.Labor and Human Capital, Livestock Production/Industries,

Influence of the water content in protoplanetary discs on planet migration and formation

The temperature and density profiles of protoplanetary discs depend crucially on the mass fraction of micrometre-sized dust grains and on their chemical composition. A larger abundance of micrometre-sized grains leads to an overall heating of the disc, so that the water ice line moves further away from the star. An increase in the water fraction inside the disc, maintaining a fixed dust abundance, increases the temperature in the icy regions of the disc and lowers the temperature in the inner regions. Discs with a larger silicate fraction have the opposite effect. Here we explore the consequence of the dust composition and abundance for the formation and migration of planets. We find that discs with low water content can only sustain outwards migration for planets up to 4 Earth masses, while outwards migration in discs with a larger water content persists up to 8 Earth masses in the late stages of the disc evolution. Icy planetary cores that do not reach run-away gas accretion can thus migrate to orbits close to the host star if the water abundance is low. Our results imply that hot and warm super-Earths found in exoplanet surveys could have formed beyond the ice line and thus contain a significant fraction in water. These water-rich super-Earths should orbit primarily around stars with a low oxygen abundance, where a low oxygen abundance is caused by either a low water-to-silicate ratio or by overall low metallicity.Comment: 15 pages, 12 figures, accepted by A&

Do investors value cash flow stability of listed infrastructure funds?

I analyze cash flow characteristics of listed infrastructure investment companies and funds and compare this unique infrastructure sample with a non-infrastructure reference group. I confirm that infrastructure investment provide more stable cash flows than non-infrastructure investments. However, I do not find that investors positively value this cash flow stability. Instead, more volatile cash flows are valued with a premium. On the other hand, earnings management proxied by accrual volatility is valued with a discount. My paper offers evidence that higher infrastructure investments in general are valued with a positive 'infrastructure premium' that is not driven by more stable cash flows. I find additional indications that transparent financial and governance structures as well as regulatory risk play a significant role for the valuation of infrastructure investment companies and funds. --infrastructure funds,cash flow volatility

Middle Management in Agriculture: Roles, Functions, and Practices

The role of middle managers in agriculture and agribusiness has been neglected by applied - as well as disciplinary - research, while gaining increasing importance in practice. This study provides an overview of middle management research and analyzes middle managers' authority in human resource decision-making and human resource management practices based on in-depth interviews analyzed through a grounded theory approach. Results show that these middle managers use both traditional and participative management practices to accomplish organizational goals, but would benefit from training tailored to their industry and specific needs.Case study research method, grounded theory, human resource management (HRM) practices, middle manager, supervisor, supervisory function, Agribusiness, Labor and Human Capital,

Migration of Earth-size planets in 3D radiative discs

In this paper, we address the migration of small mass planets in 3D radiative disks. Indeed, migration of small planets is known to be too fast inwards in locally isothermal conditions. However, thermal effects could reverse its direction, potentially saving planets in the inner, optically thick parts of the protoplanetary disc. This effect has been seen for masses larger than 5 Earth masses, but the minimum mass for this to happen has never been probed numerically, although it is of crucial importance for planet formation scenarios. We have extended the hydro-dynamical code FARGO to 3D, with thermal diffusion. With this code, we perform simulations of embedded planets down to 2 Earth masses. For a set of discs parameters for which outward migration has been shown in the range of $[5, 35]$ Earth masses, we find that the transition to inward migration occurs for masses in the range $[3, 5]$ Earth masses. The transition appears to be due to an unexpected phenomenon: the formation of an asymmetric cold and dense finger of gas driven by circulation and libration streamlines. We recover this phenomenon in 2D simulations where we control the cooling effects of the gas through a simple modeling of the energy equation.Comment: 17 pages, 20 figures, accepted. MNRAS, 201

The structure of protoplanetary discs around evolving young stars

The formation of planets with gaseous envelopes takes place in protoplanetary accretion discs on time-scales of several millions of years. Small dust particles stick to each other to form pebbles, pebbles concentrate in the turbulent flow to form planetesimals and planetary embryos and grow to planets, which undergo substantial radial migration. All these processes are influenced by the underlying structure of the protoplanetary disc, specifically the profiles of temperature, gas scale height and density. The commonly used disc structure of the Minimum Mass Solar Nebular (MMSN) is a simple power law in all these quantities. However, protoplanetary disc models with both viscous and stellar heating show several bumps and dips in temperature, scale height and density caused by transitions in opacity, which are missing in the MMSN model. These play an important role in the formation of planets, as they can act as sweet spots for the formation of planetesimals via the streaming instability and affect the direction and magnitude of type-I-migration. We present 2D simulations of accretion discs that feature radiative cooling, viscous and stellar heating, and are linked to the observed evolutionary stages of protoplanetary discs and their host stars. These models allow us to identify preferred planetesimal and planet formation regions in the protoplanetary disc as a function of the disc's metallicity, accretion rate and lifetime. We derive simple fitting formulae that feature all structural characteristics of protoplanetary discs during the evolution of several Myr. These fits are straightforward to apply for modelling any growth stage of planets where detailed knowledge of the underlying disc structure is required.Comment: Accepted by A&A, v3 corrected small typo in the fitting formula