Atmospheric ammonia (NH3) released from agriculture is contributing significantly to acidification and atmospheric NH3 may have on human health is much less readily available. The potential direct ...impact of NH3 on the health of the general public is under-represented in scientific literature, though there have been several studies which indicate that NH3 has a direct effect on the respiratory health of those who handle livestock. These health impacts can include a reduced lung function, irritation to the throat and eyes, and increased coughing and phlegm expulsion. More recent studies have indicated that agricultural NH3 may directly influence the early on-set of asthma in young children. In addition to the potential direct impact of ammonia, it is also a substantial contributor to the fine particulate matter (PM2.5) fraction (namely the US and Europe); where it accounts for the formation of 30% and 50% of all PM2.5 respectively. PM2.5 has the ability to penetrate deep into the lungs and cause long term illnesses such as Chronic Obstructive Pulmonary Disease (COPD) and lung cancer. Hence, PM2.5 causes economic losses which equate to billions of dollars (US) to the global economy annually. Both premature deaths associated with the health impacts from PM2.5 and economic losses could be mitigated with a reduction in NH3 emissions resulting from agriculture. As agriculture contributes to more than 81% of all global NH3 emissions, it is imperative that food production does not come at a cost to the world's ability to breathe; where reductions in NH3 emissions can be easier to achieve than other associated pollutants.
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•81% of global ammonia emissions are a result of agriculture.•Ammonia contributes to 50% (EU) and 30% (US) of PM2.5 air pollution.•PM2.5 causes chronic respiratory illnesses and can lead to premature mortality.•Reducing ammonia emissions can reduce ambient PM2.5, reducing premature mortality.•Regulating NH3 as a precursor to PM2.5 is cost efficient, and will protect human health.
The characterization of how entrepreneurial a region or country is, has generally been shaped by a narrow view of what actually constitutes entrepreneurship. In the case of Germany, this has led to a ...characterization of Germany as not being particularly entrepreneurial. Such a view is at odds with the remarkable, high-performing family business, widely held to be the backbone of the economy. The purpose of this paper is to suggest that the interpretation prevalent in entrepreneurship literature is problematic due to a too narrow operationalization of the entrepreneurship concept. As Zahra (
2007
; 2014) emphasized, context matters for entrepreneurship, especially on a local or spatial level. One particular organizational manifestation of entrepreneurship, family business, may be congruent in specific spatial and institutional contexts but not in others. Other geographic and institutional contexts may be congruent with the contrasting startups. Thus, an important and novel contribution of this paper is to analyze the geography of family business as distinct from startups: two ends of the entrepreneurship continuum, embedded in different kinds of entrepreneurial ecosystems. We generate innovative maps working with official data, showing the distinct distribution of both kinds of entrepreneurship in different ecosystems. These findings are connected with spatial effects, living conditions and lead to recommendations for policy measures. The paper focuses on Germany, because startups as well as family business are prevalent and can be found in all regions.
Plain English Summary Publishing entrepreneurship research is not just important but challenging. Longstanding experts in the field can provide helpful advice. As borders between academic fields ...blur, research fields are increasingly global in their perspective, knowledge, and findings, thus enabling robust participation in research fields at a scale previously unimaginable. Drawing on the experience, insights, and perspectives of three seasoned editors, we try to reconcile the seemingly incoherent and inherent frustration experienced by researchers, on the one hand, with the very purposeful and self-aware process of at least one scholarly journal, Small Business Economics: An Entrepreneurship Journal, on the other, to provide guidelines and insights to aspiring authors in what they should consider in crafting their research for submission with the goal of publication. In providing this sage council, the paper provides guidance to researchers on the process of publishing their results.
Abstract
C4 photosynthesis allows faster photosynthetic rates and higher water and nitrogen use efficiency than C3 photosynthesis, but at the cost of lower quantum yield due to the energy requirement ...of its biochemical carbon concentration mechanism. It has also been suspected that its operation may be impaired in low irradiance. To investigate fluxes under moderate and low irradiance, maize (Zea mays) was grown at 550 µmol photons m−2 s−l and 13CO2 pulse-labeling was performed at growth irradiance or several hours after transfer to 160 µmol photons m−2 s−1. Analysis by liquid chromatography/tandem mass spectrometry or gas chromatography/mass spectrometry provided information about pool size and labeling kinetics for 32 metabolites and allowed estimation of flux at many steps in C4 photosynthesis. The results highlighted several sources of inefficiency in low light. These included excess flux at phosphoenolpyruvate carboxylase, restriction of decarboxylation by NADP-malic enzyme, and a shift to increased CO2 incorporation into aspartate, less effective use of metabolite pools to drive intercellular shuttles, and higher relative and absolute rates of photorespiration. The latter provides evidence for a lower bundle sheath CO2 concentration in low irradiance, implying that operation of the CO2 concentration mechanism is impaired in this condition. The analyses also revealed rapid exchange of carbon between the Calvin–Benson cycle and the CO2-concentration shuttle, which allows rapid adjustment of the balance between CO2 concentration and assimilation, and accumulation of large amounts of photorespiratory intermediates in low light that provides a major carbon reservoir to build up C4 metabolite pools when irradiance increases.
Abstract
This is the final photometric study of TW Hya based on new MOST satellite observations. During 2014 and 2017, the light curves showed stable 3.75- and 3.69-d quasi-periodic oscillations, ...respectively. Both values appear to be closely related to the stellar rotation period, as they might be created by changing visibility of a hotspot formed near the magnetic pole directed towards the observer. These major light variations were superimposed on a chaotic, flaring-type activity caused by hotspots resulting from unstable accretion – a situation reminiscent of that in 2011, when TW Hya showed signs of a moderately stable accretion state. In 2015, only drifting quasi-periods were observed, similar to those present in 2008–2009 data and typical for magnetized stars accreting in a strongly unstable regime. A rich set of multicolour data was obtained during 2013–2017 with the primary aim of characterizing the basic spectral properties of the mysterious occultations in TW Hya. Although several possible occultation-like events were identified, they are not as well defined as in the 2011 MOST data. The new ground-based and MOST data show a dozen previously unnoticed flares, as well as small-amplitude 11 min–3 h brightness variations, associated with ‘accretion bursts’. We cannot exclude the possibility that the shortest 11–15 min variations could also be caused by thermal instability oscillations in an accretion shock.
SMEs’ internationalization and innovation activities represent fundamental economic activities that are conducive to SMEs’ individual success, but likewise contribute to the economic well-being of ...their home region and country. Therefore, understanding how some SMEs are innovative and internationally active has attracted significant scholarly attention within and beyond the SME research community. This paper highlights selected key findings from prior literature with regard to the context factors that facilitate SMEs’ internationalization and innovation. In the latter case, we focus on innovation within inter-organizational collaborations. We conclude with directions for future SME research above and beyond SMEs’ internationalization and innovation.
Through photometric monitoring of the extended transit window of HD 97658b with the MOST space telescope, we have found that this exoplanet transits with an ephemeris consistent with that predicted ...from radial velocity measurements. The mid-transit times are 5.6sigma earlier than those of the unverified transit-like signals reported in 2011, and we find no connection between the two sets of events. The transit depth together with our determined stellar radius (Rlow * = (ProQuest: Formulae and/or non-USASCII text omitted) Rmiddot in circle) indicates a (ProQuest: Formulae and/or non-USASCII text omitted) R+ in circle super-Earth. When combined with the radial velocity determined mass of 7.86 + or - 0.73 M sub(+ in circle), our radius measure allows us to derive a planet density of (ProQuest: Formulae and/or non-USASCII text omitted) g cm super(-3). Models suggest that a planet with our measured density has a rocky core that is enveloped in an atmosphere composed of lighter elements. The star of the HD 97658 system is the second brightest known to host a transiting super-Earth, facilitating follow-up studies of this not easily daunted, warm and likely volatile-rich exoplanet.
Interspecific divergence in metabolite profiles in C3 and C4 species points to differing evolutionary trajectories of the Calvin-Benson cycle in different seed plant lineages
Abstract
Low atmospheric ...CO2 in recent geological time led to the evolution of carbon-concentrating mechanisms (CCMs) such as C4 photosynthesis in >65 terrestrial plant lineages. We know little about the impact of low CO2 on the Calvin-Benson cycle (CBC) in C3 species that did not evolve CCMs, representing >90% of terrestrial plant species. Metabolite profiling provides a top-down strategy to investigate the operational balance in a pathway. We profiled CBC intermediates in a panel of C4 (Zea mays, Setaria viridis, Flaveria bidentis, and F. trinervia) and C3 species (Oryza sativa, Triticium aestivum, Arabidopsis thaliana, Nicotiana tabacum, and Manihot esculenta). Principal component analysis revealed differences between C4 and C3 species that were driven by many metabolites, including lower ribulose 1,5-bisphosphate in C4 species. Strikingly, there was also considerable variation between C3 species. This was partly due to different chlorophyll and protein contents, but mainly to differences in relative levels of metabolites. Correlation analysis indicated that one contributory factor was the balance between fructose-1,6-bisphosphatase, sedoheptulose-1,7-bisphosphatase, phosphoribulokinase, and Rubisco. Our results point to the CBC having experienced different evolutionary trajectories in C3 species since the ancestors of modern plant lineages diverged. They underline the need to understand CBC operation in a wide range of species.
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