scholarly journals Testing a theoretical framework for the environment-species abundance paradigm: a new approach to the Abundant Centre Hypothesis

2022 ◽  
Author(s):  
Alakananda Maitra ◽  
Rohan Pandit ◽  
Mansi Mungee ◽  
Ramana Athreya
Keyword(s):  
Empirical Studies ◽  
Species Abundance ◽  
Theoretical Models ◽  
Theoretical Framework ◽  
Small Degree ◽  
Individual Species ◽  
Environment Interaction ◽  
Theory Of Evolution ◽  
Average Abundance ◽  
Abundance Profile

The linkage between environment, a species' fitness and its abundance is central to the theory of evolution. So far, all studies of this linkage have been heuristic and empirical due to an inability to determine fitness either experimentally (independent of abundance) or theoretically (from species-environment interaction). One category of such studies involves the Abundant Centre Hypothesis which posits that a species' abundance rises to a maximum at the centre of its range. We argue that the confusing mix of results from ACH studies arises from ignoring the central premise that the abundance distribution cannot be independent of the environment. First, we employed a theoretical framework to identify an environmental context (an elevational transect; 200-2800 m in the eastern Himalayas) likely to favour ACH. We then improved upon some previously identified conceptual and methodological shortcomings of ACH studies. Using systematically collected bird data (245 species; 15867 records) from that transect we found that the community average abundance profile is symmetric, as expected by ACH. Notwithstanding which, the abundance profiles of individual species showed a small degree of asymmetry which was correlated with elevation. This elevational dependence may be due to the hard elevational limits at the lower and upper ends of the mountain, as expected from theoretical considerations. We also showed that the average abundance profile shape is close to gaussian, while ruling out uniform and inverted-quadratic shapes. This work demonstrates that selecting a particular category of environmental contexts can help in integrating theoretical tools into a field dominated by empirical studies. Such a union should spur the development of more detailed and testable theoretical models for better insights in an important field.

Emerging Syndromes

2017 ◽  
Author(s):  
Kelly C. Allison ◽  
Jennifer D. Lundgren
Keyword(s):  
Empirical Studies ◽  
Theoretical Models ◽  
Future Research ◽  
Night Eating Syndrome ◽  
Statistical Manual ◽  
Night Eating ◽  
Diagnostic And Statistical Manual ◽  
Impairment In Functioning ◽  
Atypical Anorexia Nervosa ◽  
Comorbid Psychopathology

The Diagnostic and Statistical Manual, fifth edition, of the American Psychiatric Association (2013) has designated several disorders under the diagnosis of otherwise specified feeding and eating disorder (OSFED). This chapter evaluates three of these, night eating syndrome (NES), purging disorder (PD), and atypical anorexia nervosa (atypical AN). It also reviews orthorexia nervosa, which has been discussed in the clinical realm as well as the popular press. The history and definition for each is reviewed, relevant theoretical models are presented and compared, and evidence for the usefulness of the models is described. Empirical studies examining the disorders’ independence from other disorders, comorbid psychopathology, and, when available, medical comorbidities, are discussed. Distress and impairment in functioning seem comparable between at least three of these emerging disorders and threshold eating disorders. Finally, remaining questions for future research are summarized.

scholarly journals Can Habitat Quality Index Measured Using the InVEST Model Explain Variations in Bird Diversity in an Urban Area?

2021 ◽  
Vol 13 (10) ◽  
pp. 5747
Author(s):  
Dehuan Li ◽  
Wei Sun ◽  
Fan Xia ◽  
Yixuan Yang ◽  
Yujing Xie
Keyword(s):  
Habitat Quality ◽  
Quality Index ◽  
Empirical Studies ◽  
Species Abundance ◽  
Diversity Indices ◽  
Local Scale ◽  
Data Availability ◽  
Bird Diversity ◽  
Invest Model ◽  
Trade Offs

Biodiversity maintenance is a crucial ecosystem service. Due to time limits and data availability, assessing biodiversity using indicators or models has become a hot topic in recent decades. However, whether some proposed indicators can explain biodiversity well at the local scale is still unclear. This study attempted to test whether the habitat quality index (HQI) as measured using the integrated valuation of ecosystem services and trade-offs (InVEST) model could explain variations in bird diversity in New Jiangwan Town, a rapidly urbanized region of Shanghai, China. The relationships from 2002 to 2013 among HQI and the two diversity indices, species richness and species abundance, were analyzed using Fisher’s exact test and gray correlation analysis. No significant association was found. Habitat connectivity was then integrated to develop a new combined indicator of habitat quality and connectivity index (HQCI). The associations between HQCI and the two diversity indices were improved significantly. The results indicated that connectivity may be an important factor explaining the diversity of certain species at a local scale. More empirical studies should be conducted to provide scientific evidence relating habitat quality to biodiversity.

Transforming the scope of the bank through fintechs: toward a modularized network governance

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Piotr Łasak ◽  
Marta Gancarczyk
Keyword(s):  
Organizational Design ◽  
Banking Sector ◽  
Transaction Cost Economics ◽  
Empirical Studies ◽  
Theoretical Framework ◽  
Network Governance ◽  
Content Type ◽  
Ict Adoption ◽  
Conceptual Foundations ◽  
Practical Implications

PurposeThe aim of this paper is to develop a theoretical framework of the transformation of the bank's scope driven by fintechs.Design/methodology/approachThe conceptual foundations for a comprehensive transformation of the bank governance through financial technologies (fintechs) are underexplored. In order to develop such foundations, the authors adopt transaction cost economics (TCE), the concepts of external enablers and a modular organizational design, as well as a systematic literature review.FindingsThe results point to three scenarios of the banks' scope, depending on the adopted technological mechanisms and related effects that change the characteristics of organizational activities, justifying new bank boundaries. The most advanced application of fintechs results in a modularized network scenario leading to the emergence of financial ecosystems.Research limitations/implicationsThe proposed micro-perspective of decisional rules in an individual organization is unique in the current literature that predominantly focuses on the banking sector at large. The identified scenarios are valuable for solid theoretical and empirical grounding and can be further exploited in decision simulations and empirical studies.Practical implicationsThe proposed theoretical framework points to the rationales and consequences of adopted technologies for the boundaries of a bank organization.Originality/valueThis paper provides three contributions to the literature on technology-driven transformations of organizations with a focus on banks. First, the authors elaborate a theoretical framework for establishing the bank's boundaries in response to the expansion of financial technologies. Second, the authors add to the knowledge accumulation in the area of organizational transformations based on the ICT adoption, in particular, to the literature on the modular organizational design. Third, the authors contribute to the decision-maker practice by proposing the alternative options of banks' scope transformed through fintechs.

scholarly journals Simulation, Control and Desire. Urban Commons and Semi-Public Space Resilience in the Age of Augmented Transductive Territorial Production

2019 ◽  
pp. 179-198 ◽  
Author(s):  
Manfredo Manfredini
Keyword(s):  
Public Space ◽  
Empirical Studies ◽  
Public Spaces ◽  
Theoretical Framework ◽  
External Control ◽  
The Public ◽  
Spatial Production ◽  
The Public Sphere ◽  
The Right ◽  
Urban Commons

Considering place-based participation a crucial factor for the development of sustainable and resilient cities in the post-digital turn age, this paper addresses the socio-spatial implications of the recent transformation of relationality networks. To understand the drivers of spatial claims emerged in conditions of digitally augmented spectacle and simulation, it focuses on changes occurring in key nodes of central urban public and semi-public spaces of rapidly developing cities. Firstly, it proposes a theoretical framework for the analysis of problems related to socio-spatial fragmentation, polarisation and segregation of urban commons subject to external control. Secondly, it discusses opportunities and criticalities emerging from a representational paradox depending on the ambivalence in the play of desire found in digitally augmented semi-public spaces. The discussion is structured to shed light on specific socio-spatial relational practices that counteract the dissipation of the “common worlds” caused by sustained processes of urban gentrification and homogenisation. The theoretical framework is developed from a comparative critical urbanism approach inspired by the right to the city and the right to difference, and elaborates on the discourse on sustainable development that informs the United Nations’ New Urban Agenda. The analysis focuses on how digitally augmented geographies reintroduce practices of participation and commoning that reassemble fragmented relational infrastructures and recombine translocal social, cultural and material elements. Empirical studies on the production of advanced simulative and transductive spatialities in places of enhanced consumption found in Auckland, New Zealand, ground the discussion. These provide evidence of the extent to which the agency of the augmented territorialisation forces reconstitutes inclusive and participatory systems of relationality. The concluding notes, speculating on the emancipatory potential found in these social laboratories, are a call for a radical redefinition of the approach to the problem of the urban commons. Such a change would improve the capacity of urbanism disciplines to adequately engage with the digital turn and efficaciously contribute to a maximally different spatial production that enhances and strengthens democracy and pluralism in the public sphere.

scholarly journals The impact of organizational culture on business operations in the Republic of Srpska and Serbia

2017 ◽  
Vol 6 (12) ◽  
Author(s):  
Svetlana Vukotić ◽  
Mirjana Čeko ◽  
Dragana Gaćinović
Keyword(s):  
Organizational Culture ◽  
National Culture ◽  
Empirical Studies ◽  
Theoretical Framework ◽  
Business Operations ◽  
The Republic ◽  
The Impact

This paper primarily provides relevant theoretical framework forexplaining the phenomenon of organizational culture, but also itanalyzes its impact on the business of an enterprise/company andworking atmosphere that occurs as a result of the impact of the organizationalclimate of a given company. Empirical studies on thissubject have been carried out in Serbia and the Republic of Srpska,which allowed us to compare the implementation and the impact ofthe organizational culture in these areas. In an integral part of thesestudies were included: types of organizational culture, the influenceof national culture on organizational culture and determination ofthe level of development of the same, all in order to improve businessoperations in Serbia and the Republic of Srpska.

scholarly journals Estimation accuracy of species abundance based on environmental DNA with relation to its production source, state, and assay methodology suggested by meta-analyses

2021 ◽  
Author(s):  
Toshiaki Jo ◽  
Hiroki Yamanaka
Keyword(s):  
Meta Analysis ◽  
Empirical Studies ◽  
Species Abundance ◽  
Environmental Dna ◽  
Efficient Estimation ◽  
Estimation Accuracy ◽  
Accurate Estimation ◽  
Abundance Estimation ◽  
Natural Environments ◽  
Promising Tool

Environmental DNA (eDNA) analysis is a promising tool for non-disruptive and cost-efficient estimation of species abundance. However, its practical applicability in natural environments is limited because it is unclear whether eDNA concentrations actually represent species abundance in the field. Although the importance of accounting for eDNA dynamics, such as transport and degradation, has been discussed, the influences of eDNA characteristics, including production source and state, and methodology, including collection and quantification strategy and abundance metrics, on the accuracy of eDNA-based abundance estimation were entirely overlooked. We conducted a meta-analysis using 56 previous eDNA literature and investigated the relationships between the accuracy (R2) of eDNA-based abundance estimation and eDNA characteristics and methodology. Our meta-regression analysis found that R2 values were significantly lower for crustaceans than fish, suggesting that less frequent eDNA production owing to their external morphology and physiology may impede accurate estimation of their abundance via eDNA. Moreover, R2 values were positively associated with filter pore size, indicating that selective collection of larger-sized eDNA, which is typically fresher, could improve the estimation accuracy of species abundance. Furthermore, R2 values were significantly lower for natural than laboratory conditions, while there was no difference in the estimation accuracy among natural environments. Our findings shed a new light on the importance of what characteristics of eDNA should be targeted for more accurate estimation of species abundance. Further empirical studies are required to validate our findings and fully elucidate the relationship between eDNA characteristics and eDNA-based abundance estimation.

scholarly journals A Systematic Review on Attachment and Sleep at Preschool Age

Children ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 895
Author(s):  
Catarina Perpétuo ◽  
Eva Diniz ◽  
Manuela Veríssimo
Keyword(s):  
Systematic Review ◽  
Attachment Security ◽  
Biological Process ◽  
Sleep Problems ◽  
Empirical Studies ◽  
Theoretical Models ◽  
Preschool Age ◽  
Future Research ◽  
Parent Child Relationships ◽  
Present Systematic Review

Sleep is a biological process that impacts nearly every domain of a child’s life. Sleep-wake regulation influences and it is highly influenced by developmental variables related to parent-child relationships, such as attachment. The main goal of the present systematic review is to analyze and integrate the findings of empirical studies investigating the relations between attachment and sleep in preschool age, a period marked by important developmental changes that challenge both attachment system and sleep-wake regulation. A database search was performed using a combination of relevant keywords, leading to the identification of 524 articles, with 19 manuscripts assessed for eligibility; finally, seven studies (2344 children) were included. Overall, the findings were not consistent, with some studies reporting significant associations between attachment security and sleep quality, as well as between attachment insecurity and sleep problems, whereas others did not find significant associations. The results are discussed in light of the available theoretical models and integrated in the context of measurement approaches to attachment and sleep heterogeneity, aiming to guide future research on the topic.

scholarly journals Decline in New Zealand's freshwater fish fauna: Effect of land use

2020 ◽  
Author(s):  
Michael Joy ◽  
KJ Foote ◽  
P McNie ◽  
M Piria
Keyword(s):  
New Zealand ◽  
Land Cover ◽  
Freshwater Fish ◽  
Native Species ◽  
Species Abundance ◽  
Fish Fauna ◽  
Fish Distribution ◽  
Individual Species ◽  
Freshwater Fish Fauna ◽  
Over Time

© 2019 CSIRO. The number of New Zealand's freshwater fish listed as threatened has increased since 1992 when the first New Zealand threat classification system list was compiled. In this study, temporal and land cover-related trends were analysed for data on freshwater fish distribution, comprising more than 20 000 records for the 47 years from January 1970 to January 2017 from the New Zealand Freshwater Fish Database. The analysis included individual species abundance and distribution trends, as well as an index of fish community integrity, namely the Index of Biotic Integrity (IBI). Of the 25 fish species that met the requirements for analysis to determine changes in the proportion of sites they occupied over time, 76% had negative trends (indicating declining occurrence). Of the 20 native species analysed for the proportion of sites occupied over time, 75% had negative trends; 65% of these were significant declines and more species were in decline at pasture sites than natural cover sites. The average IBI score also declined over the time period and, when analysed separately, the major land cover types revealed that the IBI declined at pasture catchment sites but not at sites with natural vegetation catchments.

scholarly journals Estimation of the relative abundance of species in artificial mixtures of insects using low-coverage shotgun metagenomics

2020 ◽  
Vol 4 ◽  
Author(s):  
Lidia Garrido-Sanz ◽  
Miquel Àngel Senar ◽  
Josep Piñol
Keyword(s):  
Relative Abundance ◽  
Species Abundance ◽  
Single Species ◽  
Insect Species ◽  
Individual Species ◽  
Advanced Degree ◽  
Mixed Species ◽  
Species List ◽  
Shotgun Metagenomics ◽  
Low Coverage

Amplicon metabarcoding is an established technique to analyse the taxonomic composition of communities of organisms using high-throughput DNA sequencing, but there are doubts about its ability to quantify the relative proportions of the species, as opposed to the species list. Here, we bypass the enrichment step and avoid the PCR-bias, by directly sequencing the extracted DNA using shotgun metagenomics. This approach is common practice in prokaryotes, but not in eukaryotes, because of the low number of sequenced genomes of eukaryotic species. We tested the metagenomics approach using insect species whose genome is already sequenced and assembled to an advanced degree. We shotgun-sequenced, at low-coverage, 18 species of insects in 22 single-species and 6 mixed-species libraries and mapped the reads against 110 reference genomes of insects. We used the single-species libraries to calibrate the process of assignation of reads to species and the libraries created from species mixtures to evaluate the ability of the method to quantify the relative species abundance. Our results showed that the shotgun metagenomic method is easily able to set apart closely-related insect species, like four species of Drosophila included in the artificial libraries. However, to avoid the counting of rare misclassified reads in samples, it was necessary to use a rather stringent detection limit of 0.001, so species with a lower relative abundance are ignored. We also identified that approximately half the raw reads were informative for taxonomic purposes. Finally, using the mixed-species libraries, we showed that it was feasible to quantify with confidence the relative abundance of individual species in the mixtures.

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