1,513 research outputs found
The Impact of Spatial Heterogeneity in Land Use Practices and Aquifer Characteristics on Groundwater Conservation Policy Cost
Estimation of agricultural policy cost for a given level of groundwater conservation requires the establishment of an accurate baseline condition. This is especially critical when the benefits and cost of any conservation program are generally estimated relative to the status quo policy or baseline situation. An inaccurate baseline estimate will lead to poor estimates of potential water conservation savings and agricultural policy cost. Over a 60-year planning horizon per acre net present value is as much as 29.8% higher for a study area when aquifer characteristics are assumed to be homogenous and set to their average area value than when the heterogeneity in aquifer characteristics is explicitly modeled.Aquifer Modeling, Economics, Resource /Energy Economics and Policy,
The curvilinear and conditional effects of product line breadth on salesperson performance, role stress, and job satisfaction
The impact of how product line breadth affects a salesperson is unclear in the existing literature. While numerous product lines can provide certain benefits to the salesperson, they may also have a dark side. This research examines the impact of number product lines handled by the salespeople on their performance, role stress, and job satisfaction. Based on role and schema theories, we test a series of curvilinear and conditional effects, using data collected from salespeople across multiple industries. Our analysis indicates non-linear relationships between number of product lines handled by the salesperson and salesperson performance and role stress. Further, these relationships are contingent on the complexity of products, complementarity of product lines, and lines acquired through mergers and acquisitions. These results show the complex effects of product lines on the salesperson and recognize both the benefits and drawbacks of product line breadth
The Impact of Live Cases on Student Skill Development in Marketing Courses
Live cases, where students work directly with an outside organization to solve real-world problems, can be an immersive learning experience for marketing students. Current scholarship on live case usage in marketing is limited to small samples from a handful of live case devotees. This article draws from a large, international sample of 169 marketing educators to investigate the perceived educational impacts of live cases on student skill development. Specifically, the paper explores student teamwork, conflict handling, time management, presentation, communication, and critical thinking skills. Additionally, the article explores how student skill development is affected by the amount of course time dedicated to the live case as well as faculty experience with live cases
Best Practices for and Outcomes of Implementing Live Cases in Marketing Courses
Purpose of the Study: This study aims to improve the implementation of live cases (client-based projects) in marketing classrooms. Live cases involve direct interaction between companies and students and can be valuable pedagogical tools improving student learning and skill development. However, live cases can be difficult to implement, creating uncertainty for faculty and possibly tipping the risk-reward balance away from this approach. At present, the preponderance of live case research in marketing has been constrained to small sample sizes, leaving faculty to question whether the implementation insights provided will generalize across different contexts and faculty. Method/Design and Sample: This paper derives insights from an international sample of 169 marketing faculty who have experience implementing live cases in their classrooms. The results, from more than 3,500 sections of live cases in marketing classrooms, provide guidance on key considerations of live case design and implementation. Results: Findings provide prescriptive guidance to current and potential future live case adopters regarding which marketing classes are most conducive to the technique, optimal sourcing strategies for participating companies, best practices in implementation, and outcomes of live case usage. An easy-to-follow set of six best practices is included for those interested in improving or beginning live case implementation in marketing. Value to Marketing Educators: For marketing educators, this work can enable greater use of live case pedagogy and improve success and satisfaction, providing techniques for faculty by answering perennial questions in live case implementation and outcomes in a robust international sample
Early Life Risk Factors for Incident Atrial Fibrillation in the Helsinki Birth Cohort Study
Background-Early life risk factors are associated with cardiometabolic disease, but have not been fully studied in atrial fibrillation (AF). There are discordant results from existing studies of birth weight and AF, and the impact of maternal body size, gestational age, placental size, and birth length is unknown. Methods and Results-The Helsinki Birth Cohort Study includes 13 345 people born as singletons in Helsinki in the years 1934-1944. Follow-up was through national registries, and ended on December 31, 2013, with 907 incident cases. Cox regression analyses stratified on year of birth were constructed for perinatal variables and incident AF, adjusting for offspring sex, gestational age, and socioeconomic status at birth. There was a significant U-shaped association between birth weight and AF (P for quadratic term = 0.01). The lowest risk of AF was found among those with a birth weight of 3.4 kg (3.8 kg for women [85th percentile] and 3.0 kg for men [17th percentile]). High maternal body mass index (>= 30 kg/m(2)) predicted offspring AF; hazard ratio 1.36 (95% CI 1.07-1.74, P = 0.01) compared with normal body mass index ( Conclusions-High maternal body mass index during pregnancy and maternal height are previously undescribed predictors of offspring AF. Efforts to prevent maternal obesity might reduce later AF in offspring. Birth weight has a U-shaped relation to incident AF independent of other perinatal variables.Peer reviewe
The Epithelial Sodium Channel (ENaC) Establishes a Trafficking Vesicle Pool Responsible for Its Regulation
The epithelial sodium channel (ENaC) is the rate-limiting step for sodium reabsorption across tight epithelia. Cyclic-AMP (cAMP) stimulation promotes ENaC trafficking to the apical surface to increase channel number and transcellular Na+ transport. Removal of corticosteroid supplementation in a cultured cortical collecting duct cell line reduced ENaC expression. Concurrently, the number of vesicles trafficked in response to cAMP stimulation, as measured by a change in membrane capacitance, also decreased. Stimulation with aldosterone restored both the basal and cAMP-stimulated ENaC activity and increased the number of exocytosed vesicles. Knocking down ENaC directly decreased both the cAMP-stimulated short-circuit current and capacitance response in the presence of aldosterone. However, constitutive apical recycling of the Immunoglobulin A receptor was unaffected by alterations in ENaC expression or trafficking. Fischer Rat Thyroid cells, transfected with α,β,γ-mENaC had a significantly greater membrane capacitance response to cAMP stimulation compared to non-ENaC controls. Finally, immunofluorescent labeling and quantitation revealed a smaller number of vesicles in cells where ENaC expression was reduced. These findings indicate that ENaC is not a passive passenger in regulated epithelial vesicle trafficking, but plays a role in establishing and maintaining the pool of vesicles that respond to cAMP stimulation. © 2012 Edinger et al
The Primordial Inflation Polarization Explorer (PIPER)
The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne
cosmic microwave background (CMB) polarimeter designed to search for evidence
of inflation by measuring the large-angular scale CMB polarization signal.
BICEP2 recently reported a detection of B-mode power corresponding to the
tensor-to-scalar ratio r = 0.2 on ~2 degree scales. If the BICEP2 signal is
caused by inflationary gravitational waves (IGWs), then there should be a
corresponding increase in B-mode power on angular scales larger than 18
degrees. PIPER is currently the only suborbital instrument capable of fully
testing and extending the BICEP2 results by measuring the B-mode power spectrum
on angular scales = ~0.6 deg to 90 deg, covering both the reionization
bump and recombination peak, with sensitivity to measure the tensor-to-scalar
ratio down to r = 0.007, and four frequency bands to distinguish foregrounds.
PIPER will accomplish this by mapping 85% of the sky in four frequency bands
(200, 270, 350, 600 GHz) over a series of 8 conventional balloon flights from
the northern and southern hemispheres. The instrument has background-limited
sensitivity provided by fully cryogenic (1.5 K) optics focusing the sky signal
onto four 32x40-pixel arrays of time-domain multiplexed Transition-Edge Sensor
(TES) bolometers held at 140 mK. Polarization sensitivity and systematic
control are provided by front-end Variable-delay Polarization Modulators
(VPMs), which rapidly modulate only the polarized sky signal at 3 Hz and allow
PIPER to instantaneously measure the full Stokes vector (I, Q, U, V) for each
pointing. We describe the PIPER instrument and progress towards its first
flight.Comment: 11 pages, 7 figures. To be published in Proceedings of SPIE Volume
9153. Presented at SPIE Astronomical Telescopes + Instrumentation 2014,
conference 915
The N2K Consortium. II. A Transiting Hot Saturn Around HD 149026 With a Large Dense Core
Doppler measurements from Subaru and Keck have revealed radial velocity
variations in the V=8.15, G0IV star HD 149026 consistent with a Saturn-Mass
planet in a 2.8766 day orbit. Photometric observations at Fairborn Observatory
have detected three complete transit events with depths of 0.003 mag at the
predicted times of conjunction. HD 149026 is now the second brightest star with
a transiting extrasolar planet. The mass of the star, based on interpolation of
stellar evolutionary models, is 1.3 +/- 0.1 solar masses; together with the
Doppler amplitude, K=43.3 m s^-1, we derive a planet mass Msin(i)=0.36 Mjup,
and orbital radius of 0.042 AU. HD 149026 is chromospherically inactive and
metal-rich with spectroscopically derived [Fe/H]=+0.36, Teff=6147 K, log g=4.26
and vsin(i)=6.0 km s^-1. Based on Teff and the stellar luminosity of 2.72 Lsun,
we derive a stellar radius of 1.45 Rsun. Modeling of the three photometric
transits provides an orbital inclination of 85.3 +/- 1.0 degrees and (including
the uncertainty in the stellar radius) a planet radius of 0.725 +/- 0.05 Rjup.
Models for this planet mass and radius suggest the presence of a ~67 Mearth
core composed of elements heavier than hydrogen and helium. This substantial
planet core would be difficult to construct by gravitational instability.Comment: 25 pages, 5 figures, accepted by the Astrophysical Journa
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