scholarly journals Planctomycetes in Lakes: Poor or Strong Competitors for Phosphorus?

2013 ◽  
Vol 80 (3) ◽  
pp. 819-828 ◽  
Author(s):  
Thomas Pollet ◽  
Jean-François Humbert ◽  
Rémy D. Tadonléké
Keyword(s):  
Community Structure ◽  
Aquatic Ecosystems ◽  
Nutrient Supply ◽  
Alternative View ◽  
Content Type ◽  
Nutrient Additions ◽  
P Limitation ◽  
Limiting Nutrient ◽  
Perialpine Lakes ◽  
Nutrient Amendments

ABSTRACTExperiments were conducted with water samples from two perialpine lakes with differing eutrophication status in order to examine the effects of inorganic-nutrient amendments (nitrogen as NO3−or NH4+and phosphorus as PO43−) on the dynamics, structure, and composition ofPlanctomycetesand to test the hypothesis that the community structure ofPlanctomycetesmembers and that of the other bacteria (withoutPlanctomycetes, here referred to as bacteria-wP, the most represented groups within the community) would be similarly impacted by nutrient additions. Initial samples were characterized by high total nitrogen-to-total phosphorus ratios (range, 39 to 55), suggesting P rather than N was the limiting nutrient for microbial communities. Consistent with this, P additions stimulated phytoplankton growth and affected the community structure of bacteria-wP but, surprisingly, not that ofPlanctomycetes. N additions did not significantly affect the community structures of bacteria-wP andPlanctomycetesor thePlanctomycetesphylotype composition. The estimated generation time ofPlanctomyceteswas 123 h. These findings could suggest that the generally well-accepted statement that bacteria (as a whole) are superior to phytoplankton in the ability to obtain phosphorus under P limitation might actually not hold forPlanctomycetes.Planctomycetesmight be poor competitors for P that do not respond quickly to the nutrient supply, which may help explain why their abundance is low in aquatic systems. The alternative view thatPlanctomycetescould be strong competitors for P (storing it) is also discussed. Our findings highlight the need for further studies examiningPlanctomycetes-phosphorus relationships in aquatic ecosystems.

scholarly journals Prevalence of Viral Photosynthetic and Capsid Protein Genes from Cyanophages in Two Large and Deep Perialpine Lakes

2013 ◽  
Vol 79 (23) ◽  
pp. 7169-7178 ◽  
Author(s):  
Xu Zhong ◽  
Stéphan Jacquet
Keyword(s):  
Genetic Diversity ◽  
Capsid Protein ◽  
Surface Waters ◽  
Aquatic Ecosystems ◽  
Alpine Lakes ◽  
Marine Environments ◽  
Content Type ◽  
Signature Genes ◽  
Perialpine Lakes ◽  
Lake Bourget

ABSTRACTCyanophages are important components of aquatic ecosystems, but their genetic diversity has been little investigated in freshwaters. A yearlong survey was conducted in surface waters of the two largest natural perialpine lakes in France (Lake Annecy and Lake Bourget) to investigate part of this cyanophage diversity through the analysis of both structural (e.g.,g20) and functional (e.g.,psbA) genes. We found that these cyanophage signature genes were prevalent throughout the year but that the community compositions ofg20cyanomyoviruses were significantly different between the two lakes. In contrast,psbA-containing cyanophages seemed to be more similar between the two ecosystems. We also found that a large proportion ofg20sequences grouped with cyanomyophage isolates.psbAsequences, belonging to phages ofSynechococcusspp., were characterized by distinct triplet motifs (with a novel viral triplet motif, EFE). Thus, our results show that cyanophages (i) are a diverse viral community in alpine lakes and (ii) are clearly distinct from some other freshwater and marine environments, suggesting the influence of unique biogeographic factors.

Socioeconomic effects of pension spending: evidence from Spain

2020 ◽  
Vol 47 (5) ◽  
pp. 599-617
Author(s):  
Fernando Bermejo ◽  
Eladio Febrero ◽  
Andre Fernandes Tomon Avelino
Keyword(s):  
Peer Review ◽  
Social Protection ◽  
Pension System ◽  
Decomposition Analysis ◽  
Value Added ◽  
Total Output ◽  
Alternative View ◽  
Input Output ◽  
Structural Decomposition Analysis ◽  
Content Type

PurposeThe purpose of this study is to provide broader understanding of the significant role that the pension system has in the Spanish economy by estimating the sectoral production, employment and income sustained by pensioners' consumption.Design/methodology/approachBased on input–output tables by the World Input–Output Database and consumption data from the Household Budget Survey by the Spanish Statistical Office, a demoeconomic model is applied to quantify the direct impacts, indirect impacts from interindustry links and induced impacts from income–consumption connections over a nine-year period (2006–2014). Then, the factors driving the evolution of total output, employment and value added during such period have been examined by using structural decomposition analysis.FindingsThe growing participation of consumption by pensioner households in final demand had proven crucial during the 2008 crisis to alleviate the negative trend in production and employment derived from the collapse in consumption suffered by the rest of households.Practical implicationsDetermining the underlying factors driving changes in both employment and income during the 2008 crisis can be of interest in political decision-making on the sustainability of the Spanish pension system.Social implicationsThe results of estimating both the employment and income supported by pensioners' consumption reveal the significant stabilizing effect of the public spending on pensions, particularly during the 2008 crisis.Originality/valueThe current Spanish approach of attaining the pension system sustainability by merely reducing social protection costs ignores the adverse consequences of a lower pensioners' demand. This paper addresses an alternative view in which pension spending is not considered a burden on economic growth but rather a means of improving the level of production and employment.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/IJSE-01-2019-0047

scholarly journals Interaction between simulated dense Scenedesmus dimorphus (Chlorophyta) bloom and freshwater meta-zooplankton community

2018 ◽  
Vol 77 (2) ◽  
Author(s):  
Zengling Ma ◽  
Hengguo Yu ◽  
Ronald Thring ◽  
Chuanjun Dai ◽  
Anglv Shen ◽  
...  
Keyword(s):  
Community Structure ◽  
Green Algae ◽  
Aquatic Ecosystems ◽  
Algal Blooms ◽  
Algal Bloom ◽  
Photochemical Efficiency ◽  
Zooplankton Community ◽  
Post Inoculation ◽  
Zooplankton Community Structure ◽  
Scenedesmus Dimorphus

Algal bloom has been a subject of much research, especially the occurrence of blue-green algae (cyanobacteria) blooms and their effects on aquatic ecosystems. However, the interaction between green algae blooms and zooplankton community was rarely investigated. In the present study, the effects exerted by Scenedesmus dimorphus (green alga) bloom on the community structure of zooplankton and the top-down control of the bloom process mediated by the zooplankton were evaluated using a series of laboratory cultures. The results showed that a dense S. dimorphus bloom could change the zooplankton community structure by decreasing its diversity indices, leading to the enrichment of a particular zooplankton species, Brachionus calyciflorus. In the presence of mixed species of zooplankton, the density of S. dimorphus in the culture was decreased as determined by a change in total chlorophyll a (Chl a) concentration, which was about 200 μg L-1 lower than that of the zooplankton-free culture. Furthermore, the number of species belonging to Cladocera, Copepoda and Rotifera all decreased, with all the cladocerans disappeared in the co-culture within 2 weeks of culturing, while the density of rotifers increased from 818 (±243) ind L-1 at the time of inoculation to 40733 (±2173) ind L-1 on the 14th day post-inoculation. Grazing of S. dimorphus by the rotifer B. calyciflorus neutralized its growth, and the gradual increase in B. calyciflorus density eventually led to the collapse of the bloom. Furthermore, grazing by B. calyciflorus also led to a decrease in the maximal photochemical efficiency (Fv/Fm) of photosystem II (PSII). The combined changes occurring in the zooplankton community structure during the process of S. dimorphus bloom and the negative effects of grazing on algal growth, morphology and photosynthetic activities confirmed the key role of zooplankton in the control of algal bloom. The results of the study therefore indicated that dense algal blooms caused by non-toxic algae could still remain a threat to aquatic ecosystems.

scholarly journals A meaning-based framework for customer loyalty

2020 ◽  
Vol 48 (8) ◽  
pp. 825-843 ◽  
Author(s):  
Elina Närvänen ◽  
Hannu Kuusela ◽  
Heli Paavola ◽  
Noora Sirola
Keyword(s):  
Customer Loyalty ◽  
Meaning Making ◽  
Two Dimensions ◽  
Alternative View ◽  
Content Type ◽  
Group Data ◽  
Focus Group Data ◽  
Retail Setting ◽  
Depth Interviews ◽  
Practical Implications

PurposeThis paper's purpose is to develop a meaning-based framework for customer loyalty by examining how consumers make sense of customer loyalty through meanings and metaphors.Design/methodology/approachA qualitative study based on in-depth interviews and focus group data in the retail context was conducted with Finnish customers. The data were analysed with qualitative data analysis techniques such as the constant comparative technique.FindingsThe empirical findings comprise eight loyalty meanings characterised by two dimensions. The first dimension is reflexive vs. routinised, and the second dimension is private vs. social. The loyalty types are dimensionalised through four metaphors: loyalty as freedom of choice; as being conventional and binding; and as belongingness.Practical implicationsThe findings improve the way customer loyalty currently is understood in the retail setting. The paper proposes that customer insight that utilises thick data can be used to grasp loyalty meanings. These data are rich in context and detail, and they take into account customers' everyday lives. Utilising thick data in the form of storytelling fuels customers' meaning-making related to customer loyalty, potentially enriching their relationship with the retailer.Originality/valueCustomer loyalty has been driven largely by a transactional and company-centric perspective. This article presents an alternative view of customer loyalty that accounts for the variety of meanings that customers may assign to their loyalty-related thoughts and behaviours.

scholarly journals STRUKTUR KOMUNITAS ZOOPLANKTON DI PERAIRAN KABUPATEN LOMBOK UTARA, PROVINSI NUSA TENGGARA BARAT

2018 ◽  
Vol 18 (2) ◽  
Author(s):  
Muhammad Junaidi ◽  
Nurliah Nurliah ◽  
Fariq Azhar
Keyword(s):  
Water Quality ◽  
Community Structure ◽  
Aquatic Ecosystems ◽  
Zooplankton Community ◽  
Geographical Information ◽  
Zooplankton Community Structure ◽  
Ecological Index ◽  
Physical Chemical ◽  
Chemical Conditions

ABSTRAKMengingat peranan zooplankton dalam ekosistem perairan sangat penting, maka dilakukan penelitian dengan tujuan untuk menganalisis struktur komunitas zooplankton yang meliputi jenis, kelimpahan, dan indek ekologi, dan  kaitan  distribusi zooplankton dan kualitas perairan di Perairan Kabupaten Lombok Utara. Pengumpulan data dirancang dengan sistem informasi geografis (SIG) pada 23 stasiun pengamatan yang ditentukan dengan teknik acak sederhana.  Hasil penelitian menunjukkan bahwa jenis dan kelimpahan zooplankton yang ditemukan di Perairan Kabupaten Lombok Utara cukup bervariasi dengan jumlah genus  sebanyak 9 yang terbagi  dari  5 kelas.  Berdasarkan perhitungan indeks ekologi menunjukkan bahwa struktur  komunitas zooplankton dalam kategori perairan yang kurang stabil. Kelimpahan dan indeks ekologi zooplankton  dipengaruhi oleh kondisi lingkungan (fisik-kimia) perairan antara lain  kecerahan, pH dan oksigen terlarut. Kata kunci : zooplankton,  struktur komunitas, kualitas perairan, kelimpahanABSTRACTConsidering that the role of zooplankton in aquatic ecosystems is very  important, research is carried out with the aim of analyzing zooplankton community structure which includes the type, abundance, and ecological index, and the relation of zooplankton distribution and water quality in North Lombok Regency Waters. Data collection was designed with a geographical information system (GIS) on 23 observation stations that were determined by simple random techniques. he results of this study indicate that the type and abundance of zooplankton found in the waters of North Lombok Regency are quite varied with the number of genus as many as 9 which are divided into 5 classes. Based on the calculation of the ecological index shows that the zooplankton community structure is in the category of less stable waters. The abundance and ecological index of zooplankton is influenced by the environmental (physical-chemical) conditions of the waters including brightness, pH and dissolved oxygen. Keywords: zooplankton, community structure, water quality, abundance 

Learning by failure vs learning by habits

2017 ◽  
Vol 23 (3) ◽  
pp. 524-546 ◽  
Author(s):  
Lorella Cannavacciuolo ◽  
Luca Iandoli ◽  
Cristina Ponsiglione ◽  
Giuseppe Zollo
Keyword(s):  
Learning Strategies ◽  
Diffusion Of Innovation ◽  
System Level ◽  
Alternative View ◽  
Agent Based Model ◽  
Content Type ◽  
Agent Based ◽  
Business Transactions ◽  
Virtual Lab ◽  
Start Up

Purpose The purpose of this paper is to explain the emergence of collaboration networks in entrepreneurial clusters as determined by the way entrepreneurs exchange knowledge and learn through business transactions needed to implement temporary supply chains in networks of co-located firms. Design/methodology/approach A socio-computational approach is adopted to model business transactions and supply chain formation in Marshallian industrial districts (IDs). An agent-based model is presented and used as a virtual lab to test the hypotheses between the firms’ behaviour and the emergence of structural properties at the system level. Findings The simulation findings and their validation based on the comparison with a real world cluster show that the topological properties of the emerging network are influenced by the learning strategies and decision-making criteria firms use when choosing partners. With reference to the specific case of Marshallian IDs it is shown that inertial learning based on history and past collaboration represents in the long term a major impediment for the emergence of hubs and of a network topology that is more conducive to innovation and growth. Research limitations/implications The paper offers an alternative view of entrepreneurial learning (EL) as opposed to the dominant view in which learning occurs as a result of exceptional circumstances (e.g. failure). The results presented in this work show that adaptive, situated, and day-by-day learning has a profound impact on the performance of entrepreneurial clusters. These results are encouraging to motivate additional research in areas such as in modelling learning or in the application of the proposed approach to the analysis of other types of entrepreneurial ecosystems, such as start-up networks and makers’ communities. Practical implications Agent-based model can support policymakers in identifying situated factors that can be leveraged to produce changes at the macro-level through the identification of suitable incentives and social networks re-engineering. Originality/value The paper presents a novel perspective on EL and offers evidence that micro-learning strategies adopted and developed in routine business transactions do have an impact on firms’ performances (survival and growth) as well as on systemic performances related to the creation and diffusion of innovation in firms networks.

How financial systems and firm strategy impact the choice of innovation funding

2019 ◽  
Vol 23 (2) ◽  
pp. 251-272
Author(s):  
Jaime Sierra
Keyword(s):  
Decision Making ◽  
Firm Strategy ◽  
Alternative View ◽  
Illustrative Case ◽  
Strategic Decisions ◽  
Policy Makers ◽  
Content Type ◽  
Investment Theory ◽  
Innovation Characteristics

Purpose The funding of innovation is explained by typical cost-based financial approaches. This paper breaks away from such tradition, and the purpose of this paper is to propose an alternative view where innovation funding decisions are strategic and concern interactions between actors – each with their own characteristics and strategic intentions – project features, and traits of the setting in which interactions take place. Design/methodology/approach This paper builds up an alternative framework to understand how innovation is financed by considering the interplay of innovation characteristics, the strategic reasons of project owners and funders, and the role of the matching environment and conditions. This proposal includes explanatory elements overlooked by extant theories. An illustrative case is presented to support the need for this proposal. Findings The framework proposed proves useful to better understand innovation funding cases where the traditional financial theory does not suffice. Practical implications Innovative companies may improve decision making about resource allocation to innovation; innovation funders may refine their decision-making criteria and implementation; and policy makers and practitioners need to devise better supporting strategies for innovative companies. Originality/value This proposal considers a continuum of funding options where supply/demand will match on the grounds of strategic decisions made during the interaction itself, under certain contextual conditions. Hence, it enriches the understanding of strategic decisions regarding firm capital structure and investment theory when it comes to funding innovation.

scholarly journals Modification of the Gastric Mucosal Microbiota by a Strain-Specific Helicobacter pylori Oncoprotein and Carcinogenic Histologic Phenotype

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Jennifer M. Noto ◽  
Joseph P. Zackular ◽  
Matthew G. Varga ◽  
Alberto Delgado ◽  
Judith Romero-Gallo ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Community Structure ◽  
Microbial Community ◽  
Iron Deficiency ◽  
Dependent Manner ◽  
Content Type ◽  
Β Diversity ◽  
H Pylori ◽  
Gastric Microbiota

ABSTRACT Helicobacter pylori is the strongest risk factor for gastric adenocarcinoma; however, most infected individuals never develop this malignancy. Strain-specific microbial factors, such as the oncoprotein CagA, as well as environmental conditions, such as iron deficiency, augment cancer risk. Importantly, dysbiosis of the gastric microbiota is also associated with gastric cancer. To investigate the combinatorial effects of these determinants in an in vivo model of gastric cancer, Mongolian gerbils were infected with the carcinogenic cag+ H. pylori strain 7.13 or a 7.13 cagA isogenic mutant, and microbial DNA extracted from gastric tissue was analyzed by 16S rRNA sequencing. Infection with H. pylori significantly increased gastric inflammation and injury, decreased α-diversity, and altered microbial community structure in a cagA-dependent manner. The effect of iron deficiency on gastric microbial communities was also investigated within the context of infection. H. pylori-induced injury was augmented under conditions of iron deficiency, but despite differences in gastric pathology, there were no significant differences in α- or β-diversity, phyla, or operational taxonomic unit (OTU) abundance among infected gerbils maintained on iron-replete or iron-depleted diets. However, when microbial composition was stratified based solely on the severity of histologic injury, significant differences in α- and β-diversity were present among gerbils harboring premalignant or malignant lesions compared to gerbils with gastritis alone. This study demonstrates that H. pylori decreases gastric microbial diversity and community structure in a cagA-dependent manner and that as carcinogenesis progresses, there are corresponding alterations in community structure that parallel the severity of disease. IMPORTANCE Microbial communities are essential for the maintenance of human health, and when these communities are altered, hosts can become susceptible to inflammation and disease. Dysbiosis contributes to gastrointestinal cancers, and specific bacterial species are associated with this phenotype. This study uses a robust and reproducible animal model to demonstrate that H. pylori infection induces gastric dysbiosis in a cagA-dependent manner and further that dysbiosis and altered microbial community structure parallel the severity of H. pylori-induced gastric injury. Ultimately, such models of H. pylori infection and cancer that can effectively evaluate multiple determinants simultaneously may yield effective strategies for manipulating the gastric microbiota to prevent the development of gastric cancer.

scholarly journals Effects of Disinfection on Legionella spp., Eukarya, and Biofilms in a Hot Water System

2012 ◽  
Vol 78 (19) ◽  
pp. 6850-6858 ◽  
Author(s):  
Maha Farhat ◽  
Marina Moletta-Denat ◽  
Jacques Frère ◽  
Séverine Onillon ◽  
Marie-Cécile Trouilhé ◽  
...  
Keyword(s):  
Community Structure ◽  
Heat Shock ◽  
Legionella Pneumophila ◽  
Water System ◽  
Single Strand Conformation Polymorphism ◽  
Pilot Scale ◽  
Small Subunit ◽  
Hot Water ◽  
Content Type ◽  
Chemical Treatments

ABSTRACTLegionellaspecies are frequently detected in hot water systems, attached to the surface as a biofilm. In this work, the dynamics ofLegionellaspp. and diverse bacteria and eukarya associated together in the biofilm, coming from a pilot scale 1 system simulating a real hot water system, were investigated throughout 6 months after two successive heat shock treatments followed by three successive chemical treatments. Community structure was assessed by a fingerprint technique, single-strand conformation polymorphism (SSCP). In addition, the diversity and dynamics ofLegionellaand eukarya were investigated by small-subunit (SSU) ribosomal cloning and sequencing. Our results showed that pathogenicLegionellaspecies remained after the heat shock and chemical treatments (Legionella pneumophilaandLegionella anisa, respectively). The biofilm was not removed, and the bacterial community structure was transitorily affected by the treatments. Moreover, several amoebae had been detected in the biofilm before treatments (Thecamoebaesp.,Vannellasp., andHartmanella vermiformis) and after the first heat shock treatment, but onlyH. vermiformisremained. However, another protozoan affiliated with Alveolata, which is known as a host cell forLegionella, dominated the eukaryal species after the second heat shock and chemical treatment tests. Therefore, effectiveLegionelladisinfection may be dependent on the elimination of these important microbial components. We suggest that eradicatingLegionellain hot water networks requires better study of bacterial and eukaryal species associated withLegionellain biofilms.

scholarly journals Dominant Tree Species and Soil Type Affect the Fungal Community Structure in a Boreal Peatland Forest

2016 ◽  
Vol 82 (9) ◽  
pp. 2632-2643 ◽  
Author(s):  
Hui Sun ◽  
Eeva Terhonen ◽  
Andriy Kovalchuk ◽  
Hanna Tuovila ◽  
Hongxin Chen ◽  
...  
Keyword(s):  
Community Structure ◽  
Community Composition ◽  
High Throughput ◽  
Fungal Community ◽  
Tree Species ◽  
High Throughput Sequencing ◽  
Soil Layer ◽  
Fungal Community Composition ◽  
Content Type ◽  
Boreal Peatlands

ABSTRACTBoreal peatlands play a crucial role in global carbon cycling, acting as an important carbon reservoir. However, little information is available on how peatland microbial communities are influenced by natural variability or human-induced disturbances. In this study, we have investigated the fungal diversity and community structure of both the organic soil layer and buried wood in boreal forest soils using high-throughput sequencing of the internal transcribed spacer (ITS) region. We have also compared the fungal communities during the primary colonization of wood with those of the surrounding soils. A permutational multivariate analysis of variance (PERMANOVA) confirmed that the community composition significantly differed between soil types (P< 0.001) and tree species (P< 0.001). The distance-based linear models analysis showed that environmental variables were significantly correlated with community structure (P< 0.04). The availability of soil nutrients (Ca [P= 0.002], Fe [P= 0.003], and P [P= 0.003]) within the site was an important factor in the fungal community composition. The species richness in wood was significantly lower than in the corresponding soil (P< 0.004). The results of the molecular identification were supplemented by fruiting body surveys. Seven of the genera ofAgaricomycotinaidentified in our surveys were among the top 20 genera observed in pyrosequencing data. Our study is the first, to our knowledge, fungal high-throughput next-generation sequencing study performed on peatlands; it further provides a baseline for the investigation of the dynamics of the fungal community in the boreal peatlands.

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