1,449 research outputs found
Nonparametric Efficiency Analysis for Coffee Farms in Puerto Rico
Coffee production in Puerto Rico is labor intensive since harvest is done by hand for quality and topography conditions. Färe's nonparametric approach was used to estimate technical, allocative, scale and overall efficiency measures for coffee farms in Puerto Rico during the 2000 to 2004 period. On average Puerto Rico coffee farms were 46% technically efficient, 79% scale efficient, and 74% allocatively efficient.coffee production, nonparametric efficiency, Crop Production/Industries, Research Methods/ Statistical Methods,
Quantity and quality: Increasing safety norms through after action reviews
Workplace safety is a concern for both scholars and practitioners alike because accidents and injuries can result in time away from work and lost organizational resources. This study focuses on how one type of post-incident discussion can be effectively used to promote positive safety norms. It adds to the growing body of research on after action review meetings, one type of post-incident discussion intervention commonly used in high reliability organizations to increase future workplace safety behaviors. This study also extends the sensemaking and high reliability literatures by examining a three-way interaction between perceived frequency of after action review meetings, ambiguity reduction and psychological safety. Survey data were obtained from 330 firefighters. Results from the three-way interaction showed that safety norms were highest when perceived after action review frequency, ambiguity reduction and psychological safety were simultaneously high, and safety norms were lowest when perceived after action review frequency, ambiguity reduction and psychological safety were simultaneously low. By examining both the perceived quantity and quality of after action review meetings, this study provides insight into which after action review facilitation objectives are most likely to increase positive safety norms and ultimately create a shared understanding of how to behave safely in future workplace events in high reliability organizational contexts
Pollen-pistil interactions and self-incompatibility in the Asteraceae: new insights from studies of Senecio squalidus (Oxford ragwort)
Background Pollen-pistil interactions are an essential prelude to fertilization in angiosperms and determine compatibility/incompatibility. Pollen-pistil interactions have been studied at a molecular and cellular level in relatively few families. Self-incompatibility (SI) is the best understood pollen-pistil interaction at a molecular level where three different molecular mechanisms have been identified in just five families. Here we review studies of pollen-pistil interactions and SI in the Asteraceae, an important family that has been relatively understudied in these areas of reproductive biology. Scope We begin by describing the historical literature which first identified sporophytic SI (SSI) in species of Asteraceae, the SI system later identified and characterized at a molecular level in the Brassicaceae. Early structural and cytological studies in these two families suggested that pollen-pistil interactions and SSI were similar, if not the same. Recent cellular and molecular studies in Senecio squalidus (Oxford ragwort) have challenged this belief by revealing that despite sharing the same genetic system of SSI, the Brassicaceae and Asteraceae molecular mechanisms are different. Key cellular differences have also been highlighted in pollen-stigma interactions, which may arise as a consequence of the Asteraceae possessing a ‘semi-dry' stigma, rather than the ‘dry' stigma typical of the Brassicaceae. The review concludes with a summary of recent transcriptomic analyses aimed at identifying proteins regulating pollen-pistil interactions and SI in S. squalidus, and by implication the Asteraceae. The Senecio pistil transcriptome contains many novel pistil-specific genes, but also pistil-specific genes previously shown to play a role in pollen-pistil interactions in other species. Conclusions Studies in S. squalidus have shown that stigma structure and the molecular mechanism of SSI in the Asteraceae and Brassicaceae are different. The availability of a pool of pistil-specific genes for S. squalidus offers an opportunity to elucidate the molecular mechanisms of pollen-pistil interactions and SI in the Asteracea
trans-Dibromidobis(triphenylphosphane)platinum(II) chloroform monosolvate
Both the platininum complex and the solvent molecule of the title compound, [PtBr2(C18H15P)2]·CHCl3, are located on a twofold rotation axis. The CH unit and the Cl atoms of the CHCl3 molecule are disordered over two equally occupied positions. The complex shows a trans square-planar geometry about the Pt atom
Rational design of a (S)-selective-transaminase for asymmetric synthesis of (1S)-1-(1,1′-biphenyl-2-yl)ethanamine
Amine transaminases offer an environmentally sustainable synthesis route for the production of pure chiral amines. However, their catalytic efficiency toward bulky ketone substrates is greatly limited by steric hindrance and therefore presents a great challenge for industrial synthetic applications. We hereby report an example of rational transaminase enzyme design to help alleviate these challenges. Starting from the Vibrio fluvialis amine transaminase that has no detectable catalytic activity toward the bulky aromatic ketone 2-acetylbiphenyl, we employed a rational design strategy combining in silico and in vitro studies to engineer the transaminase enzyme with a minimal number of mutations, achieving an high catalytic activity and high enantioselectivity. We found that, by introducing two mutations W57G/R415A, detectable enzyme activity was achieved. The rationally designed variant, W57F/R88H/V153S/K163F/I259M/R415A/V422A, showed an improvement in reaction rate by more than 1716-fold toward the bulky ketone under study, producing the corresponding enantiomeric pure (S)-amine (enantiomeric excess (ee) value of >99%)
Less acting, more doing: How surface acting relates to perceived meeting effectiveness and other employee outcomes
This study adds to the growing body of research on work meetings and extends the emotional labour literature beyond a service context by examining the relationship between surface acting during meetings and perceived meeting effectiveness. Additionally, the relationships of surface acting during meetings and perceived meeting effectiveness with time-lagged reports of intention to quit and emotional exhaustion 3 months later were investigated. Structural equation modelling of data from 178 working adults revealed negative relationships between surface acting and perceptions of meeting effectiveness. Perceived meeting effectiveness partially mediated the relationship between surface acting and both intention to quit and emotional exhaustion 3 months later. These findings expand both the limited research on perceived meeting effectiveness and the surface acting nomological network to include a consideration that expressing inauthentic emotions in meetings (surface acting) may relate to the perceived effectiveness of the meeting. As well, both surface acting during meetings and perceived meeting effectiveness may relate to how emotionally exhausted employees feel and their intentions to seek other employment. Given the cost and pervasiveness of meetings in daily organizational life and their potential effects on the well-being of employees, understanding how to make meetings effective is paramount – particularly if researchers and practitioners want to better understand how perceived meeting effectiveness may be related to various employee outcomes
Diel transcriptional response of a California Current plankton microbiome to light, low iron, and enduring viral infection
Phytoplankton and associated microbial communities provide organic carbon to oceanic food webs and drive ecosystem dynamics. However, capturing those dynamics is challenging. Here, an in situ, semi-Lagrangian, robotic sampler profiled pelagic microbes at 4 h intervals over ~2.6 days in North Pacific high-nutrient, low-chlorophyll waters. We report on the community structure and transcriptional dynamics of microbes in an operationally large size class (>5 μm) predominantly populated by dinoflagellates, ciliates, haptophytes, pelagophytes, diatoms, cyanobacteria (chiefly Synechococcus), prasinophytes (chiefly Ostreococcus), fungi, archaea, and proteobacteria. Apart from fungi and archaea, all groups exhibited 24-h periodicity in some transcripts, but larger portions of the transcriptome oscillated in phototrophs. Periodic photosynthesis-related transcripts exhibited a temporal cascade across the morning hours, conserved across diverse phototrophic lineages. Pronounced silica:nitrate drawdown, a high flavodoxin to ferredoxin transcript ratio, and elevated expression of other Fe-stress markers indicated Fe-limitation. Fe-stress markers peaked during a photoperiodically adaptive time window that could modulate phytoplankton response to seasonal Fe-limitation. Remarkably, we observed viruses that infect the majority of abundant taxa, often with total transcriptional activity synchronized with putative hosts. Taken together, these data reveal a microbial plankton community that is shaped by recycled production and tightly controlled by Fe-limitation and viral activity
Stability of wheat grain yields over three field seasons in the UK
Ensuring food security in a changing climate is a major contemporary challenge and requires development of climate resilient crops that perform well under variable environments. The hypothesis that yield stability in sub-optimal conditions is linked to yield penalties in optimal conditions was investigated in field-grown wheat in the UK. The phenotypic responses, rate of wheat crop development and final grain yield, to varying sowing date, rainfall, air temperature and radiation patterns were studied for a panel of 61 elite commercial wheat cultivars grown in the UK in 2012, 2013 and 2014. Contrasting climatic patterns, particularly rainfall accumulation and distribution over the season, influenced the relative performance of the cultivars affecting the duration of grain development stage and impacting on productivity. Indices for crop productivity, yield stability and performance under sub-optimal conditions revealed four cultivars with a combination of stable and high relative grain yields over the three seasons: Gladiator, Humber, Mercato and Zebedee. Genetic similarity between cultivars partially explained yield performance in the contrasting seasons. The year of release of the cultivars correlated with grain yield but not with yield stability, supporting the contention that breeding for yield potential does not select for climate resilience and yield stability of crops. Further analysis of the outstanding cultivars may unravel target traits for breeding efforts aimed at increasing wheat yield potential and stability in the changing climate. This article is protected by copyright. All rights reserved
Depressive episodes, symptoms, and trajectories in women recently diagnosed with breast cancer.
Depression carries serious psychosocial, physical, and economic consequences for cancer survivors. Study goals were to characterize patterns and predictors of depressive symptoms and major depressive episodes in recently diagnosed breast cancer patients. Consecutively recruited women (N = 460) completed a validated interview (CIDI) and questionnaire measure (CES-D) of depression within 4 months after invasive breast cancer diagnosis and at six additional assessments across 12 months. Outcomes were major depressive episodes, continuous symptom scores, and latent symptom trajectory classes. Across 12 months, 16.6 % of women met criteria for a major depressive episode. Unemployment predicted depressive episodes after other correlates were controlled. Distinct trajectory classes were apparent: an estimated 38 % of women had chronically elevated symptoms (High trajectory), 20 % recovered from elevated symptoms (Recovery), and 43 % had lower symptoms (Low and Very Low trajectories). Although 96 % of episodes occurred in the High or Recovery classes, 66 % of women in the High trajectory did not have an episode. Women in the Low (vs High) trajectory were more likely to be older, retired, more affluent, and have fewer comorbid diseases and briefer oncologic treatment. Women in the Recovery trajectory (vs High) were more likely to be married and more affluent and have fewer comorbid diseases. Assuming available therapeutic resources, assessment of both depressive symptoms and episodes over several months after diagnosis is important. Identification of patients at risk for persistently high depressive symptoms (e.g., younger, longer treatment course) opens targeted opportunities to prevent and promote rapid recovery from depression
- …