Information systems, like biological systems, are susceptible to external perturbations. Similar to flora and fauna in a biome, species of data can be classified within a dataphora [26]. While entropic properties and data geometries can be used to describe local species of data within a dataphora, they are not designed to describe the global properties of an information system or evaluate its stability [30][31]. Ecologists have used Information Theories to describe macro-level properties of biological ecosystems [17] and statistical tools to evaluate biological systems [9]. This research leverages an ecological perspective to model information systems as a living system [14]. Our findings support the theory of dataphoric ascendancy with Wikipedia having a Diversity Index value of 0.68, within the range of 0.65 and 0.80 that indicates a balanced state. We further support our findings with additional evaluations of other ecosystems including the predicted collapse of the information service known as the Digital Universe. This research allows for an information system’s stability to be a) characterized and b) predicted using ecological measures specific to the diversity of data within the ecosystem.

Introduction

The theory of dataphoric space describes an information system as a biologically-styled biome in which “species of information” reside [26]. Dataphoric space can structure the components of a data-driven ecosystem at a local level (e.g., dataphores, histological data forms and cellular data forms). While these are locally driven phenomenon within an information system, they do not quantitatively describe the global properties of an information system (See Figure 1. Position of a Dataphora). Understanding global properties of information systems are critical to measuring the evolution of an information system over time. This framework advances information system research by providing an instrument for longitudinal, comparative and point-in-time analyses. In the 1950s there was cross-disciplinary interest in merging the concepts of information theory [27] and ecology [17]. Ecologists for many years have used theories of information to describe the fauna of a biome in terms of a “diversity index”. While informaticists have adopted some ecological concepts and indices, the field has not fully embraced the ecological framework of a living system as a function of an information system. To what extent can information scientists leverage global measures of biological systems for information systems research? [11] Using a quantitative design science approach, we have developed instrumentation towards this goal.

Limited non-farm opportunities in the rural areas of the developing world, coupled with population growth, means agriculture will continue to play a dominant role as a source of livelihood in these areas. Thus, while rural transformation has dominated recent literature as a way of improving welfare through diversifying into non-farm sectors, improving productivity and resilience to shocks in smallholder agricultural production cannot be downplayed. This is especially so given the changing climatic conditions affecting agricultural production, and thus threatening many livelihoods in rural areas. Farm diversification is an important strategy for creating resilience against climatic shocks in farm production. Using cross-sectional data from northern Namibia, the study assesses the barriers and success factors related to effective crop and livestock enterprises diversification and the effect of these on food security outcomes. A Seemingly Unrelated Regression model is used to assess the joint factors explaining total farm diversification, while a step-wise error correction model is used to evaluate the conditional effect of diversification in each of the two farm enterprises on two measures of food security: food expenditure and dietary diversity. We find that past exposure to climate shocks informs current diversification levels and that access to climate information is a key success factor for both livestock and crop diversification. In terms of food security, greater diversification in either crop or livestock production leads to higher food security outcomes, with neither crop nor livestock diversification showing dominance in affecting food security outcomes. However, an overall higher level of diversification in both livestock and crop enterprises is dominant in explaining food security outcomes.

Introduction

Risk is inherent in small-scale rain-fed agricultural production. Farmers have to contend with seasonal weather uncertainties, the threat of pests and diseases, and post-harvest losses, among other risks. These risks are being exacerbated by the effects of a changing climate; for example, the severity and distribution of important livestock and crop diseases is changing, while incidents of droughts and floods are on the rise (Elad & Pertot, 2014; Thornton, van de Steeg, Notenbaert, & Herrero, 2009; Wetherald & Manabe, 2002). These effects of climate change are expected to increase poverty incidences in most developing countries and create new poverty pockets in countries with increasing inequality (IPCC, 2014). Agricultural production has been stagnant in Sub-Saharan Africa (SSA), and there is consensus that the current trend in productivity cannot guarantee food security in the region (Jayne, Chamberlin, & Headey, 2014; Kyalo Willy, Muyanga, & Jayne, 2019; Onyutha, 2018). Climatic shocks that further adversely affect food production are a serious threat to food security and livelihoods in the region. While there are adaptation options that can create resilience in agricultural productivity, studies continue to show low adoption rates across the region (Bradshaw, Dolan, & Smit, 2004; Di Falco, Veronesi, & Yesuf, 2011; Mulwa, Marenya, Rahut, & Kassie, 2017; Singh et al., 2017; Smit & Wandel, 2006). In crop farming, such adaptation measures include using seeds adapted to climate-stressors (for example drought resistant seeds) and spreading risks across different crop types (Howden et al., 2007).

1- Introduction

2- Literature review

3- Methodology

4- Results

5- Discussion and conclusions

References

Abstract

Sustainable business model innovation is about creating superior customer and firm value by addressing societal and environmental needs through the way business is done. Business models require intentional design if they are to deliver aspired sustainability impacts. Scant research has been done on ‘ecologies’ of different business models in order to understand and improve these and create positive impact on the environment, society, economy and other key stakeholders. Hence, in this paper a novel framework is presented to enable a systemic form of sustainable business model experimentation. The framework is based on the recognition of three key issues which have not yet been sufficiently incorporated in the literature on sustainable business models: construct clarity, boundary setting and uncertainty about outcomes. These concepts are discussed first. Building on earlier work, the resulting framework incorporates potential side-effects and boundary setting based on the concept of an ‘ecology of business models’. Second, an approach is proposed that could stimulate more profound forms of sustainable business model innovation: The Ecology of Business Models Experimentation map. Third, the approach is illustrated through two cases. The approach could help minimise symbiotic dependency on less sustainable business models; help destroy unsustainable business models by outcompeting them; and maximise contributions to favourable institutional infrastructures for more sustainable business models. This paper contributes to research on sustainable business model innovation, design and experimentation by providing a potential approach for ‘business model ecology redesign’.

Introduction

Sustainable business models are currently a major focus in academic literature, and also among business practitioners and policy makers dealing with the ecological and social impact production and consumption systems. Yet there is uncertainty about the outcome of business model innovations for sustainability (Mont, 2002; Tukker, 2004, 2015; Lüdeke-Freund and Dembek, 2017). Sustainable business model innovation is about creating superior customer and firm value through addressing societal and environmental needs (Boons and Lüdeke-Freund, 2013). To this end, a company should actively seek to create positive societal and environmental value and optimise value for itself as well as for a wider network of stakeholders, including Society and Environment as stakeholders, thus optimising value for the ‘system’ (Stubbs and Cocklin, 2008). However, creating ‘shared value’ across stakeholders is difficult to realise in practice (Porter and Kramer, 2011). Tools such as the Triple Layer Business Model Canvas (Joyce and Paquin, 2016), Flourishing business canvas (Upward and Jones, 2016) and Value Mapping Tool (Bocken et al., 2013) have been developed to support a systemic view on sustainable business modelling. We argue for a more inclusive perspective when experimenting with sustainable business models (Weissbrod and Bocken, 2017). This follows from considering three key issues: construct clarity, boundary setting and uncertainty about outcomes.

1- Introduction

2- Water; one of the prerequisites for life as we know it

3- Isoscapes

4- Stable isotope ecology

5- Forensic isotope ecology

6- Caveats — a fishy example

7- Conclusions

8- The science bit: isotopologues, chemically identical yet not the same

References

Abstract

Stable isotope ecology and forensic isotope ecology are not only linked by name. More often than not, knowledge and insights gained through the former serve as a springboard for application focused work of the latter. This review aims to offer a glimpse into the fascinating world of both though with more emphasis on forensic isotope ecology. To this end a selection of past and recent published work is presented and discussed to highlight both potential and limitations of isotopic analytical approaches to the detection of illegal trade in plants and animals.

Introduction

Ecology, and its underpinning environmental studies, are two areas within natural and life sciences with a long history of applying stable isotope chemistry and bio-chemistry to gain insights into, for example, food webs, life cycles, or migration. It was only a matter of time before the methods that were developed, and the insights gained during ecological studies, were extended to wildlife forensics. For the appreciation of as wide an audience as possible, in addition to highlighting the wealth of information that stable isotope abundance signatures can provide, in Section 8 this review also provides some background information on the nature of stable isotopes, the terminology used, and why their relative abundance varies in the natural world. In-depth treatises on the subject of stable isotope chemistry in the context of ecological, geochemical, and forensic sciences, have been published in the form of several textbooks [1–5].

Increased biodiversity can make valuable contributions to food production and security around the world. The role of plant species diversity for “ecological intensification” of agriculture has been widely recognised, but the potential contribution of multi-trophic-level production systems, such as rice-fish coculture, has received less attention. A continuous 4-year experiment (2015e2018) was conducted comparing rice-fish (yellow finless eel and loach) co-culture, and mono-rice planting practices on the Chongming Eco-island of China. During the experiment, pests (insect herbivores and weeds), arthropods, pesticides, grain and marketable fish yield were sampled, soil quality (available nitrogen, phosphorus and potassium, total nitrogen, organic matter content and pH) and rice grain quality (protein content, chalkiness, gel consistency, amylose content) were evaluated, and an economic analysis were performed. Fish decreased herbivore insect abundance by 24.07%, reduced weeds abundance, richness and biomass by 67.62, 62.01 and 58.88% respectively, increased invertebrate predator abundance by 19.48%, and reduced the need for pesticide by 23.4%. Co-culture practice produced an average economic values 10.33% higher than in the mono-rice farming. In addition, rice-fish co-culture enhanced both soil and rice quality. Our results confirm that rice-fish co-culture can be an effective form of ecological intensification, incorporating and contributing ecosystem services in agricultural production and increasing sustainability.

Introduction

Agricultural intensification has been recognised one of the main reasons for biodiversity loss and related decline in ecosystem functioning due to the conversion of natural habitats into monoculture farming areas (Gagic et al., 2012; Batary et al., 2017 ; Hass et al., 2018; Plue et al., 2018). Intensive use of agrochemicals is reducing environmental quality (Stehle and Schulz, 2015; He et al., 2017; Ruiz and MarAa Dolores, 2018 ~ ), damaging local plant communities (Cassman, 1999; Kremen et al., 2012), and reducing the abundance and richness of beneficial arthropods (Gagic et al., 2012; Kovacs-Hosty anszki et al., 2017 ). The concept of “ecological intensification” has been promoted to redesign agroecosystems, based on the increased use of ecological processes and biodiversity, using resource more efficiently, and decreasing anthropogenic inputs (Bommarco et al., 2013; Pywell et al., 2015; Bowles et al., 2016). In this framework, it has been showed that plant-diversified farming practices can contribute to ecological intensification of agriculture by providing multiple ecosystem services, promoting biological pest control (Redlich et al., 2018; Wan et al., 2018), decreasing the use of pesticides (Tscharntke et al., 2005; Gurr et al., 2016; Zhao et al., 2016), improving soil quality (Cassman, 1999), and enhancing crop yields (Tittonell and Giller., 2013; Gurr et al., 2016). The potential contribution of multi-trophic-level production systems, such as rice-fish co-culture, to ecological intensification has not received as much attention.

In this article I discuss the factors contributing to the drafting and approval of the forestry incentives law (PINPEP) in Guatemala. This is a remarkable law because (a) it is among the few in the country recognizing property rights to land other than private property; (b) it has a stronger focus on subsidies and social benefits than on market mechanisms and; (c) the law is the result of the effort of forestry community organizations. My findings indicate that community organizations can, through their alliances with science-policy networks, participate in law-making and by that, in democratizing environmental governance. My study nuances the role of experts in environmental governance showing that their power and status should be understood as relational and historically contingent. Furthermore, some key and charismatic individuals can act as door openers to link community forestry organizations and science-policy networks. Although the identity of the grassroots organizations that participated in the process of making the law is tied to forestry, these organizations have a long history in the country. This history has been shaped by their experiences in exile and in refugee camps during the civil war as well as by their contact with development assistance organizations.

Introduction

The idea to implement monetary transfers to forest owners or forest dwellers to promote global forest conservation has become popular in national and international policy-making circles. Programs such as “Payments for Ecosystem Services-PES” and “Reduced Emissions from Deforestation and Forest Degradation-REDD” are good examples of such initiatives. This increased focus on so-called “market-based” mechanisms for nature conservation is in part related to what many have called “the neoliberal turn” in nature conservation, involving also the privatisation and commoditization of nature (Castree, 2004, 2008; McCarthy and Prudham 2004; Mansfield 2004; Bakker 2005; Heynen and Robbins, 2005). Fairhead et al. (2012) observe that there has been an explosion in studies analysing the effects of the neoliberal turn in environmental conservation. They argue that such literature has however tended to adopt a rather uniform position assuming a singular hegemonic project, failing sometimes to analyse the consequences for diverse, differentiated and contingent settings. This paper aims to contribute to a better understanding of how neoliberal ideas are transformed, re-shaped, negotiated and contested in national and local contexts. This paper offers a detailed analysis of a policy making process to reveal the underlying processes at play that contribute to shape the outcomes of the expansion of neoliberal programs in Central America. Investigating the complex interactions between science and politics allows me to suggest a more nuanced understanding of the conditions under which unexpected alliances and policy outcomes emerge. These alliances might not change radically the position of marginalized actors, but contribute to advance their agendas and to improve their political possibilities in the future. In 2010, the Guatemalan congress passed the law on forestry incentives for smallholders (PINPEP law, Decree 51-2010). This is a landmark law for various reasons. First, this is one of the few in the country, acknowledging the existence of communal land tenure regimes and recognizing property rights that are not formalized in the National Property Register. Land tenure is a contested issue in Guatemala, a country featuring enormous inequality in access to land and land distribution, where an estimated five percent of the population controls 80 percent of arable land, complicated by unsecure land tenure for the majority (Gauster and Isakson, 2007). Second, the approval of the law was pushed by community forestry organizations. Many other proposals for laws promoted by peasant organizations or petitions to reform laws have not had the success that one would expect considering the broad mobilizations behind these initiatives. Third, the spirit of the law focuses on providing subsidies to small landholders for conserving or planting trees in their lands.

1- Introduction

2- Antagonism

3- Facilitation

4- Host community interactions

5- Habitat modification by ecosystem engineers

6- Challenges and future goals

7- Conclusions

References

Abstract

Entomopathogenic nematodes (EPNs) have potential to control many soil-dwelling insect pests but have been limited in their usage, partly by their unpredictable field performance. Numerous abiotic and biotic factors are thought to contribute to this poor predictability, but the exact impacts and relative importance of these factors in affecting EPN performance in the field are not well understood. Previous studies have highlighted diverse interactions between EPNs and other members of the soil community, from plants and fungi to arthropods and annelids. These interactions may help or hinder EPNs in a variety of ways. However, current research has yet to determine how many of these interactions influence EPN performance under field conditions, specifically, if they contribute to the variability limiting EPN efficacy and wide-scale adoption. Here we outline current knowledge of these interactions as well as challenges and avenues for future research, such as greater integration of EPN research with soil animal and rhizosphere ecology, that will better elucidate the potential, limitations, and proper use of EPNs in pest management.

Introduction

Since the discovery of entomopathogenic nematodes (EPNs) in 1923 and their first commercialization sixty years later, thirteen EPN species of the genera Steinernema and Heterorhabditis have been commercially cultivated and marketed for use in a wide array of agricultural and horticultural systems (Lacey et al., 2015). EPN infective juveniles (IJs) invade insect bodies through the mouth, anus, spiracles, or cuticle (Lewis et al., 2006; Wang and Gaugler, 1998) and release their bacterial symbionts (Xenorhabus spp. bacteria for Steinernema spp. nematodes, and Photorhabdus spp. bacteria for Heterorhabditis spp. nematodes) into the insect’s hemolymph. The bacteria release toxins to kill the insect, though sometimes are aided by venom proteins and anti-immune agents produced by the nematodes themselves (Lu et al., 2017), and proliferate in the cadaver. The IJs consume the bacteria, complete their development, and reproduce. After one or more generations of nematodes inside the cadaver, new IJs leave to seek new hosts in the soil (Kaya and Gaugler, 1993; Lewis and Clarke, 2012). When using EPNs against pests in agricultural and horticultural systems, IJs are commonly applied onto soil as an aqueous suspension sprayed through the same kind of device used to apply a chemical pesticide. Many other application techniques exist, such as applying EPNs through drip irrigation systems or applying them contained within bait capsules or already-infected insect cadavers (Shapiro-Ilan and Dolinski, 2015). EPNs can effectively provide a non-toxic, environmentally benign alternative to chemical insecticides for the control of some soil-dwelling pests, including white grubs (Grewal et al., 2005), citrus root weevil (Shapiro-Ilan et al., 2005, 2002), and mole crickets (Parkman et al., 1996). However, despite these and other successes (Georgis et al., 2006), extensive use of EPNs in agriculture is limited to a few markets, including citrus orchards (Shapiro-Ilan et al., 2005) and vegetables in greenhouses (Dolinski et al., 2012; Lacey and Georgis, 2012). Despite the safety of EPNs for humans, other vertebrates, and many non-target invertebrates (Georgis et al., 2006; Lacey and Georgis, 2012), their variable performance and persistence remain important factors restricting their adoption by pest managers (Georgis et al., 2006; Georgis and Gaugler, 1991; Shapiro-Ilan et al., 2002). For instance, many studies of EPN efficacy against scarab grubs in turf and nursery crop systems report highly variable control even within the same EPN species (Georgis et al., 2006; Grewal et al., 2005). Increasing knowledge of how abiotic and biotic soil characteristics affect and contribute to variability in EPN performance and persistence will be a crucial task to better optimize EPNs for soil pest management. In addition, while many applied EPNs do not persist in soil longer than a few weeks or months (Ebssa and Koppenhöfer, 2011; Gaugler et al., 1997; Smits, 1996; Susurluk and Ehlers, 2008), some native EPN populations, adapted to a particular environment, have been shown to persist over multiple years when isolated, cultured, and applied to the soil (Koppenhöfer and Fuzy, 2009; Shields et al., 1999). This interest in using persistent EPN populations underscores the need for understanding the biotic and abiotic factors that limit or promote EPN persistence.

Many lowland tropical rainforests are strongly phosphorus (P) depleted (Sollins 1998; Mirmanto et al. 1999; Vitousek et al. 2010; Wright et al. 2011) and they harbour some of the highest plant diversity on the planet (Wright 2002). Biotic forces, including plant-associated soil fungi, play a key role in promoting plant diversity (Klironomos 2002; Bell, Freckleton & Lewis 2006; Petermann et al. 2008; Mangan et al. 2010; *Correspondence author. E-mail: jonesfr@science.oregonstate.edu Schnitzer & Klironomos 2011). Fungi interact with plant communities in mutualistic, pathogenic, and commensal ways (Rosenblueth & Mart
ınez-Romero 2006; Smith & Read 2008b; Van Der Heijden, Bardgett & Van Straalen 2008; Dodds & Rathjen 2010). Fungi play critical roles in ecosystem processes including decomposition and nutrient cycling, and they have been hypothesized to play a critical role in the maintenance of plant diversity via pathogen-mediated negative density dependent survival (Janzen 1970; Connell 1971; Augspurger 1983; Clark & Clark 1984; Carson et al. 2008; Timothy Paine et al. 2008; Hol et al. 2013; Bagchi et al. 2014; Comita et al. 2014; but also see Hyatt et al. 2003) and plant-soil feedbacks (Bever 2002; Mangan et al. 2010; Philippot et al. 2013). Despite their recognized role in these processes, the relative importance of the abiotic and biotic drivers of soil fungal community structure and diversity in lowland tropical forests remains poorly understood. Soil properties can determine soil fungal communities and host-microbe interactions (Lauber et al. 2008; Vinale et al. 2008). For example, arbuscular mycorrhizal (AM) fungi (subphylum Glomeromycotina) form associations with 80% of plant species worldwide (Wang & Qiu 2006; Brundrett 2009), and enhance the uptake of water, inorganic P, and other relatively immobile nutrients by effectively increasing root surface area and therefore increasing the volume of soil explored (Smith, Anderson & Smith 2015). The symbiosis between plants and AM fungi can be facultative and dependent on the plant’s soil nutrient requirements and resource availability (Heijden & Kuyper 2001; Lambers et al. 2008; Dumbrell et al. 2009; Albornoz et al. 2016a). Similarly, P and other soil properties can affect non-AM fungal communities, such as ectomycorrhizal fungi (Albornoz et al. 2016b), saprophytic fungi (Kerekes et al. 2013), and pathogens (Toljander et al. 2006; Tedersoo et al. 2016). Nevertheless, fungi are only partially driven by soil properties, and other factors, such as biotic interactions, simultaneously structure fungal communities. Plant communities can also affect their associated fungal communities (Johnson et al. 2004; Prescott & Grayston 2013) due to differences in fungal host specificity, defined as the taxonomic range of plant host species (Molina & Trappe 1982; Botnen et al. 2014). For example, obligate pathogens experience high selection pressure to infect hosts and reciprocal natural selection can occur between hosts and pathogens. This leads to an ‘evolutionary arms race’ between pathogen effectors and plant immunity genes, resulting in increased host specificity of pathogens (Jones & Dangl 2006; Dodds & Rathjen 2010; Brown & Tellier 2011). In contrast, AM fungi are thought to be generalists in forming host associations (i.e. a broad range of hosts; Davison et al. 2015) compared to other fungal groups such as saprophytes, pathogens, and endophytes (Tedersoo et al. 2010). Because of the host specificity that many fungal clades exhibit, they are thought to be strongly coupled with plant communities (Davey et al. 2015; Gao et al. 2015). However, the effects of plant community composition relative to soil chemistry in structuring fungal communities remains largely unknown, and studies that quantitatively determine the relative impact of each are scarce.

Glyphosate (N-(phosphonomethyl) glycine) is a post-emergence, non-selective, foliar herbicide. It is the most used herbicide in Argentina, accounting for 62% of the commercialized pesticides in the market (CASAFE, 2012). It is used as a weed controller in no-till (NT) systems, and it is also applied on various genetically modified crops (e.g. soybean, corn, cotton). Glyphosate has an amine, carboxylate, and phosphonate group. It is a highly water-soluble compound (11.6 g L1 at 25º C), but it also has a high affinity to soil particles, such as clays and aluminum and iron oxides (Vereecken, 2005). The biological degradation of a pesticide in the soil is dependent on various factors such as: microbiological activity, organic matter (OM) content, nutrient availability, pH, salinity, temperature, oxygen content, humidity and bio-availability (Aislabie and Lloydjones, 1995; Walker et al., 2001; Borggaard and Gimsing, 2008). Glyphosate is mainly degraded by biological activity, although evidence of an abiotic pathway via metal interaction has been recently reported (Ascolani Yael et al., 2014). In general, microorganisms use glyphosate aerobically or anaerobically, as a source of organic phosphorous (Zboinska et al., 1992; Dick and Quinn 1995; Obojska et al., 2002; Ermakova et al., 2008). However, some species have been described to be capable of using glyphosate as a carbon or nitrogen source (Kryosko and Lupicka, 1997; Obojska et al., 1999). There are two pathways known for the degradation of glyphosate (Fig. 1). In one pathway, the herbicide is hydrolyzed to inorganic phosphorous and sarcosine, by the activity of a C-P lyase enzyme. Sarcosine is then metabolized into glycine and formaldehyde by a sarcosine oxidase, until its complete mineralization to CO2 and NH3. Some examples of bacteria that use this pathway are Arthrobacter spp., Rhizobium spp. and Pseudomonas spp. (Dick and Quinn, 1995; Kishore and Jacob, 1987; Liu et al., 1991). Other organisms degrade glyphosate by an oxidoreductase, producing glyoxylate and aminomethylphosphonic acid (AMPA). Glyoxylate enters the glyoxylate bypass of the Krebs cycle, while AMPA is exported into the extracellular space (Jacob et al., 1988). Some bacteria are capable of metabolizing AMPA by a C-P lyase, yielding inorganic phosphorous and methylamine (Pipke et al., 1987; Kertesz et al., 1994), which further fully metabolizes to CO2 and NH3. Examples of microorganisms that use this pathway are Ochromobactrum anthropi (Sviridov et al., 2012) and Geobacillus caldoxylosilyticus (Obojska et al., 2002).

The anaerobic degradation of organic matter accounts for a significant part of the global carbon cycle and involves the production of the greenhouse gas CH4 (Reeburgh, 2003). While the terminal processes liberating CH4 have been thoroughly investigated using isotopic techniques (Conrad, 2005), the contribution of other pathways during the anaerobic degradation is not well investigated. In this study we aimed to specify the contribution of acetogenesis to the acetate pool in rice paddy soils from two geographical origins (Philippines and Italy). The unifying trait of acetogenic bacteria is that acetate is their major product, which is mainly formed by the acetyl-CoA pathway reducing CO2 to acetate. However, the usage of the acetyl-CoA pathway in acetogens is versatile (Drake et al., 2002; Schuchmann and Muller, 2016): acetogens can compete with primary fermenters for monomeric compounds, e.g., glucose, fructose or xylose; they can act as secondary fermenters using lactate, ethanol or even methoxylated aromatics; many acetogens can grow chemolithotrophically converting H2 and CO2 to acetate; and some acetogens can even grow in syntrophic associations at the expense of acetate running the acetyl-CoA pathways in the reverse direction (Hattori et al., 2000; Hattori, 2008). Even though acetate is the major end product of acetogens, their environmental role is hard to address since many anaerobic bacteria also produce acetate by other biochemical pathways than the acetylCoA pathway. To investigate the function of chemolithotrophic acetogens in rice field soils we studied their contribution to the acetate pool using isotope techniques. This is a reasonable approach since studies of microbial pure cultures have shown that the stable carbon isotope fractionation of most fermentative processes is almost negligible (< 5‰) (Blair et al., 1985; Penning and Conrad, 2006; Botsch and Conrad, 2011), while in contrast the fractionation by chemolithotrophic acetogenesis (4 H2 + 2 CO2→ CH3COOH + 2 H2O) is strong (−38‰ to −68‰) (Gelwicks et al., 1989; Preuss et al., 1989; Blaser et al., 2013). One has to keep in mind that the acetate formed by heterotrophic acetogenesis originates partially from fermentation of organic matter and partially from the reduction of CO2 (Freude and Blaser, 2016). However, while the differentiation of aceticlastically and hydrogenotrophically formed CH4 is rather straight forward (Conrad, 2005; Blaser and Conrad, 2016), the application of such techniques for the investigation of chemolithotrophic acetogenic bacteria is much more complex. In contrast to CH4, which is an end product in most anaerobic sediments, acetate is produced and consumed by different metabolic pathways, which all imprint a signature on the stable carbon isotope composition (13C/12C) of acetate (Fig. 1) (Conrad et al., 2014). Hence, the stable carbon isotopic composition of acetate is basically governed by three factors: (1) the isotopic composition of its precursors, (2) the isotopic fractionations (enrichment factors) associated with its formation and consumption, and (3) the relative rates of all acetate producing and consuming processes which influence its pool size. The knowledge of all three factors is of great importance for the evaluation of 13C values of acetate determined in environmental samples.

Plants close stomata to avoid losing water through transpiration under water limiting conditions (Chaves, 1991), a physiological response that is related to either hydraulic or chemical signals (Davies and Zhang, 1991; Christmann et al., 2007). Plant acclimation to water deficits involves morphological changes that regulate water balance, with plants showing decreases in leaf area and shoot/root ratio (Pimentel, 2004). Cell osmoregulation by solutes such as sugars, glycine-betaine, and proline is another response to water deficits, allowing the maintenance of water content and protecting cellular structures (Verlues et al., 2006). Rapid stomatal response to changes in water availability is an important feature in sugarcane (Saccharum spp.), preventing excessive loss of leaf turgor and further decreases in leaf water content (Ribeiro et al., 2013). However, it is well-known that stomatal closure causes low CO2 availability for photosynthetic enzymes (Du et al., 1996; Chaves et al., 2009; Machado et al., 2013) and then an imbalance between photochemical and biochemical reactions in the leaves. Therefore, production of reactive oxygen species (ROS) is enhanced under drought conditions, and plants should be able to control such deleterious molecules through their antioxidant system. This protective system consists of several enzymatic and non-enzymatic compounds, which prevent oxidative damage by scavenging ROS inside cells (Mittler, 2002). For instance, increases in superoxide dismutase and ascorbate peroxidase activities were associated with rapid recovery of leaf gas exchange in sugarcane plants after rehydration (Sales et al., 2013). These reported plant responses to a single drought event are quite common; however, plants are exposed to recurrent cycles of drought and rehydration in nature, and the consequences of such repetitive drought events are less understood (Walter et al., 2011). Plants can acclimate to varying water conditions through morphological and physiological changes, which favor the maintenance of plant growth or survival under stressful conditions (Chaves et al., 2002). Some changes during an acclimation period can allow faster responses and enhanced plant performances during the next stressful event. In fact, an experimental design with repeated cycles of droughts is a more realistic approach when considering plants in their natural environment, with improved plant performances under limiting conditions being found in several species when there was previous exposure to stressful conditions. While Trifolium alexandrinum was able to maintain high leaf water potential and relative water content after a second drought event (Iannucci et al., 2000), Quercus ilex exhibited reductions in leaf water potential and transpiration accompanied by osmotic adjustment after hardening (Villar-Salvador et al., 2004). Seedlings of Moringa oleifera that had previously been subjected to osmotic stress experienced increased drought tolerance, with plants showing higher water-use efficiency, higher photosynthesis and increases in activity of antioxidant enzymes under water deficit conditions (Rivas et al., 2013). However, most of these studies compared plants of differing ages under varying stress intensities and environmental conditions, which makes the study of stress memory difficult.

مقاله سال 2016

مقدمه
اگرچه گیاهان اکسیژن را از طریق فتوسنتز تولید می کنند ، اما کمبود یک سیستم کارآمد برای انتقال اکسیژن به ارگان های غیر فتوسنتزی نشان می دهد که این ارگان ها ممکن است در صورت محدود شدن اکسیژن از خارج ، از اکسیژن محدود شوند. علاوه بر این ، غوطه ور شدن کامل گیاه به واسطه ی سیل ممکن است منجر به دسترسی پایین به اکسیژن در اندام های بالاتر از زمین شود ، به خصوص زمانی که آلودگی آب فتوسنتز را محدود می کند. زمانی که اکسیژن برای تنفس محدود شود ، گیاهان هیپوکسی را تجربه می کنند ، در حالی که فقدان کامل اکسیژن (آنوکسی) برای بقای گیاه بیش تر مضر است. هم هیپوکسی و هم آنوکسی (کمبود اکسیژن) موجب برنامه نویسی مجدد ساختار ژن با القای متابولیسم خمیری می شوند و گیاه را قادر به استفاده از گلیکولیز برای تولید ATP می سازند. تغییرات آب و هوا باعث دسترسی بیش از اندازه به آب می شوند و در برخی نواحی منجر به خشکسالی می شوند ، در حالی که جاری شدن سیل به علت بارندگی شدید سایر مناطق جغرافیایی را تحت تاثیر قرار می دهد. به غیر از این در برخی از موارد انواع جدید محصولات قادر به مقاومت در برابر تنش های غیر زنده می باشند ، و حاصلخیزی به شدت تحت تاثیر قرار خواهد گرفت. تا یک دهه پیش اطلاعات کمی در رابطه با ژن هایی که تحمل در برابر غوطه ور شدن را افزایش می دادند وجود داشت ، و در طول سال های اخیر مکانیسم های ملکولی مربوط به سنجش اکسیژن و سیگنال دهی در گیاهان توسعه یافتند. در این بررسی ، یافته های اخیر در زمینه ی گیاهان غیرهوازی از اکوفیزیولوژی گیاهان که در تالاب ها رشد می کنند ، مورد توجه قرار دارند.

The rise of the Internet in the last two decades has provided a new medium through which news can be conveyed and, as such, has allowed journalists not affiliated with professional newsrooms to offer up news accounts. Known as “citizen journalists,” these reporters have borne witness to many dramatically noteworthy news events in recent years, such as the 2014 race riots in Ferguson, Missouri, the sinking of a ferry in South Korea in April 2014 that killed hundreds, and the Boston Marathon bombing in 2013. Accordingly, the role of citizen journalists in crisis situations like these and others (e.g., California wildfires, Superstorm Sandy, massive tornadoes in the U.S. Midwest and Southern states) has been receiving more attention in emergency management circles (Novak & Vidoloff, 2011; Watson & Wadhwa, 2013). In each of these instances citizen journalists were present, capturing video, gathering information, and transmitting accounts in real time. As such, citizen journalists are playing an increasingly important role in the news-gathering process, especially at a time when traditional newsrooms continue to cut their staffs (Jurkowitz, 2014; Total employment, 2013). There are now hundreds of citizen journalism sites providing news from non-professionals; according to a Pew Institute study, between January 2011 and March 2012 approximately 40% of the most viewed news videos came directly from citizens placing their videos on the Internet (Jurkowitz & Hitlin, 2013).

Still, public relations literature has done little to examine citizen journalists as a rising stakeholder group within the wider news milieu. Certainly, public relations research has, over the last two decades, investigated how the Internet has affected the news ecology within which public relations practitioners attemptto convey news abouttheir clients. Particularly notable is Ye and Ki’s (2012) survey of 27 years of peer-reviewed public relations journal articles concerning the Internet. Signifi- cantly, they found that public relations scholarship was transmission centered: public relations literature focused heavily on how practitioners conceptualize and execute what they consider to be effective communication through the Internet. They pointed out that audience-centered public relations research was lacking. Not surprisingly, their study found no peerreviewed research on citizen journalists as a separate stakeholder group within the news arena that has distinct perceptions of public relations people. This study addresses that gap, inspired by Ye and Ki’s call that public relations scholarship should expand to move beyond “organizations’ or practitioners’ perceptions to also include publics’ experiences” (2012, p. 426). As such, this works reports on a study of the viewpoints of citizen journalists about public relations practitioners and the materials they offer.