At the forefront: evidence of the applicability of using environmental DNA to quantify the abundance of fish populations in natural lentic waters with additional sampling considerations

Environmental DNA (eDNA) sampling has proven to be a valuable tool for detecting species in aquatic ecosystems. Within this rapidly evolving field, a promising application is the ability to obtain quantitative estimates of relative species abundance based on eDNA concentration rather than traditionally labor-intensive methods. We investigated the relationship between eDNA concentration and Arctic char (Salvelinus alpinus) abundance in five well-studied natural lakes; additionally, we examined the effects of different temporal (e.g., season) and spatial (e.g., depth) scales on eDNA concentration. Concentrations of eDNA were linearly correlated with char population estimates ([Formula: see text] = 0.78) and exponentially correlated with char densities ([Formula: see text] = 0.96 by area; 0.82 by volume). Across lakes, eDNA concentrations were greater and more homogeneous in the water column during mixis; however, when stratified, eDNA concentrations were greater in the hypolimnion. Overall, our findings demonstrate that eDNA techniques can produce effective estimates of relative fish abundance in natural lakes. These findings can guide future studies to improve and expand eDNA methods while informing research and management using rapid and minimally invasive sampling.

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Unveiling biogeographical patterns of the ichthyofauna in the Tuichi basin, a biodiversity hotspot in the Bolivian Amazon, using environmental DNA

PLoS ONE ◽

10.1371/journal.pone.0262357 ◽

2022 ◽

Vol 17 (1) ◽

pp. e0262357

Author(s):

Cédric Mariac ◽

Fabrice Duponchelle ◽

Guido Miranda ◽

Camila Ramallo ◽

Robert Wallace ◽

...

Keyword(s):

Aquatic Ecosystems ◽

National Park ◽

Amazon Basin ◽

Management Strategies ◽

Environmental Dna ◽

Biodiversity Hotspot ◽

Species Level ◽

Specific Primers ◽

Future Studies ◽

Bolivian Amazon

To date, more than 2400 valid fish species have been recorded in the Amazon basin. However, some regions remain poorly documented. This is the case in the Beni basin and in particular in one of its main sub-basins, the Tuichi, an Andean foothills rivers flowing through the Madidi National Park in the Bolivian Amazonia. The knowledge of its ichthyological diversity is, however, essential for the management and protection of aquatic ecosystems, which are threatened by the development of infrastructures (dams, factories and cities), mining and deforestation. Environmental DNA (eDNA) has been relatively little used so far in the Amazon basin. We sampled eDNA from water in 34 sites in lakes and rivers in the Beni basin including 22 sites in the Tuichi sub-basin, during the dry season. To assess the biogeographical patterns of the amazonian ichthyofauna, we implemented a metabarcoding approach using two pairs of specific primers designed and developed in our laboratory to amplify two partially overlapping CO1 fragments, one of 185bp and another of 285bp. We detected 252 fish taxa (207 at species level) among which 57 are newly identified for the Beni watershed. Species compositions are significantly different between lakes and rivers but also between rivers according to their hydrographic rank and altitude. Furthermore, the diversity patterns are related to the different hydro-ecoregions through which the Tuichi flows. The eDNA approach makes it possible to identify and complete the inventory of the ichthyofauna in this still poorly documented Amazon basin. However, taxonomic identification remains constrained by the lack of reference barcodes in public databases and does not allow the assignment of all OTUs. Our results can be taken into account in conservation and management strategies and could serve as a baseline for future studies, including on other Andean tributaries.

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Quantitative estimates of average geomagnetic axial dipole dominance in deep geological time

Nature Communications ◽

10.1038/s41467-020-19794-7 ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

Andrew J. Biggin ◽

Richard K. Bono ◽

Domenico G. Meduri ◽

Courtney J. Sprain ◽

Christopher J. Davies ◽

...

Keyword(s):

Power Law ◽

Geomagnetic Field ◽

Recent Observation ◽

Observational Constraint ◽

Angular Dispersion ◽

Geological Time ◽

Future Studies ◽

Axial Dipole ◽

Quantitative Estimates

AbstractA defining characteristic of the recent geomagnetic field is its dominant axial dipole which provides its navigational utility and dictates the shape of the magnetosphere. Going back through time, much less is known about the degree of axial dipole dominance. Here we use a substantial and diverse set of 3D numerical dynamo simulations and recent observation-based field models to derive a power law relationship between the angular dispersion of virtual geomagnetic poles at the equator and the median axial dipole dominance measured at Earth’s surface. Applying this relation to published estimates of equatorial angular dispersion implies that geomagnetic axial dipole dominance averaged over 107–109 years has remained moderately high and stable through large parts of geological time. This provides an observational constraint to future studies of the geodynamo and palaeomagnetosphere. It also provides some reassurance as to the reliability of palaeogeographical reconstructions provided by palaeomagnetism.

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Carnivore Size and Quaternary Climatic Change in Southern Africa

Quaternary Research ◽

10.1016/0033-5894(86)90089-x ◽

1986 ◽

Vol 26 (1) ◽

pp. 153-170 ◽

Cited By ~ 74

Author(s):

Richard G. Klein

Keyword(s):

South Africa ◽

Southern Africa ◽

Late Quaternary ◽

Geochemical Data ◽

Mathematical Relationship ◽

Carnivore Species ◽

Quantitative Estimates ◽

The Relationship ◽

Problematic Aspect ◽

Cool Conditions

The relationship between carnassial length and latitude south is analyzed for 17 African carnivore species to determine if individuals tend to be larger in cooler climates, as predicted by Bergmann's Rule. With modern data in support, middle and late Quaternary temperatures might then be inferred from mean carnassial length in fossil samples, such as those from Equus Cave, Elandsfontein, Sea Harvest. Duinefontein, and Swartklip in the Cape Province of South Africa. One problematic aspect of the study is the use of carnassial length and latitude as necessary but imperfect substitutes for body size and temperature, respectively. For some species, another difficulty is the relatively small number of available modern specimens, combined with their uneven latitudinal spread. Still, in 14 of the species, carnassial length does tend to increase with latitude south, while mean carnassial length in the same species tends to be greater in those fossil samples which accumulated under relatively cool conditions, as inferred from sedimentologic, palynological, or geochemical data. Given larger modern samples from a wide variety of latitudes, refinement of the mathematical relationship between carnassial length and latitude in various species may even permit quantitative estimates of past temperatures in southern Africa.

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Implications of Autonomous Vehicles for Accessibility and Transport Equity: A Framework Based on Literature

Sustainability ◽

10.3390/su13084448 ◽

2021 ◽

Vol 13 (8) ◽

pp. 4448

Author(s):

Alberto Dianin ◽

Elisa Ravazzoli ◽

Georg Hauger

Keyword(s):

Conceptual Model ◽

Transport System ◽

Urban Areas ◽

Autonomous Vehicles ◽

Scientific Literature ◽

Social Groups ◽

Future Studies ◽

Social Accessibility ◽

The Relationship

Increasing accessibility and balancing its distribution across space and social groups are two fundamental goals to make transport more sustainable and equitable. In the next decades, autonomous vehicles (AVs) could significantly transform the transport system, influencing accessibility and transport equity. In particular, depending on the assumed features of AVs (e.g., private or collective) and the considered spatial, social, and regulative context (e.g., rural or urban areas), impacts may be very different. Nevertheless, research in this field is still limited, and the relationship between AV assumptions and accessibility impacts is still partially unclear. This paper aims to provide a framework of the key and emerging aspects related to the implications of AVs for accessibility and transport equity. To set this framework, we perform an analysis of the scientific literature based on a conceptual model describing the implications of AVs for the distribution of accessibility across space and social groups. We recognize four main expected impacts of AVs on accessibility: (1) accessibility polarization, (2) accessibility sprawl, (3) exacerbation of social accessibility inequities, and (4) alleviation of social accessibility inequities. These impacts are described and analyzed in relation to the main AV assumptions expected to trigger them through different mechanisms. Based on the results, some recommendations for future studies intending to focus on the relation between AVs, accessibility, and transport equity are provided.

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Association between obstructive sleep apnea and persistent-postural perceptual dizziness

Journal of Vestibular Research ◽

10.3233/ves-201508 ◽

2021 ◽

pp. 1-6

Author(s):

Anand K. Bery ◽

Jayson Lee Azzi ◽

Andre Le ◽

Naomi S. Spitale ◽

Judith Leech ◽

...

Keyword(s):

Obstructive Sleep Apnea ◽

Sleep Apnea ◽

Sensitivity And Specificity ◽

Berlin Questionnaire ◽

Future Studies ◽

Obstructive Sleep ◽

Chronic Dizziness ◽

Patients At Risk ◽

The Mean ◽

The Relationship

BACKGROUND: Obstructive sleep apnea (OSA) has been linked to vestibular dysfunction, but no prior studies have investigated the relationship between Persistent Postural Perceptual Dizziness (PPPD), a common cause of chronic dizziness, and OSA. OBJECTIVE AND METHODS: We determined the frequency of OSA in an uncontrolled group of PPPD patients from a tertiary dizziness clinic based on polysomnogram (PSG). We then assessed the sensitivity and specificity of common OSA questionnaires in this population. RESULTS: Twenty-five patients with PPPD underwent PSG (mean age 47, 60% female, mean BMI 29.5). A majority, or 56%, of patients were diagnosed with OSA, and in most, the OSA was severe. OSA patients were older (56 years versus 40 years, p = 0.0006) and had higher BMI (32 versus 26, p = 0.0078), but there was no clear gender bias (56% versus 64% female, p = 1.00). The mean sensitivity and specificity of the STOP BANG questionnaire for detecting OSA was 86% and 55%, respectively. Sensitivity and specificity of the Berlin Questionnaire was 79% and 45%, respectively. CONCLUSIONS: The prevalence of OSA was much higher in our small PPPD group than in the general population. Screening questionnaires appear to demonstrate good sensitivity to detect PPPD patients at risk of OSA in this small study. Future studies should confirm these findings and determine whether treatment of OSA improves symptoms in PPPD.

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What Matters for Job Security? Exploring the Relationships among Symbolic, Instrumental Images, and Attractiveness for Corporations in South Korea

Sustainability ◽

10.3390/su13094854 ◽

2021 ◽

Vol 13 (9) ◽

pp. 4854

Author(s):

Juyeon Oh ◽

Seunghwan Myeong

Keyword(s):

Undergraduate Students ◽

Organizational Context ◽

Job Security ◽

Corporate Image ◽

Causal Claim ◽

Cross Sectional ◽

Future Studies ◽

Collectivistic Cultures ◽

Symbolic Image ◽

The Relationship

This study examines the extent to which the symbolic and instrumental images and attractiveness toward an organization are related. This study further focuses on global human resource management and reports findings from two studies: Study 1 uses the data from undergraduate students, and Study 2 cross-validates the findings of Study 1 by using actual data from employees. The distinction of this study from previous works is that the present work focuses on a Korean organizational context (collectivistic cultures) and the differences between the potential applicants and employees in the perception of an organization′s attractiveness. Furthermore, it investigates the relationship between the symbolic and instrumental images toward organizations, unlike existing relative research. The results show that the symbolic and instrumental images are related, and the perceptions of the corporate image differ for the potential applicants and employees in the context of collectivistic cultures. The more competent employees consider their organization to be, the more job security they perceive their organization to provide. Moreover, the symbolic image of being competent is negatively related to the instrumental image of job security. Since this study used cross-sectional data, future studies need to use longitudinal data to establish our model′s causal claim empirically and investigate the underlying reasons behind these differences.

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Dreams of Truck Drivers: A Test of the Continuity Hypothesis of Dreaming

Imagination Cognition and Personality ◽

10.2190/578d-mlha-78r2-htnw ◽

2005 ◽

Vol 25 (2) ◽

pp. 179-186 ◽

Cited By ~ 2

Author(s):

Michael Schredl ◽

Arthur Funkhouser ◽

Nicole Arn

Keyword(s):

Empirical Studies ◽

Truck Drivers ◽

The Other ◽

Continuity Hypothesis ◽

Future Studies ◽

Daytime Activity ◽

Close Relationship ◽

The One ◽

Dream Emotions ◽

The Relationship

Empirical studies largely support the continuity hypothesis of dreaming. The present study investigated the frequency and emotional tone of dreams of truck drivers. On the one hand, the findings of the present study partly support the continuity regarding the time spent with driving/being in the truck and driving dreams and, on the other hand, a close relationship was found between daytime mood (feelings of stress, job satisfaction) and dream emotions, i.e., different dream characteristics were affected by different aspects of daytime activity. The results, thus, indicate that it is necessary to define very clearly how this continuity is to be conceptualized. The approach of formulating a mathematical model (cf. [1]) should be adopted in future studies in order to specify the factors and their magnitude in the relationship between waking and dreaming.

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Perceptions of time at work

Personnel Review ◽

10.1108/pr-02-2014-0033 ◽

2016 ◽

Vol 45 (1) ◽

pp. 29-50 ◽

Cited By ~ 6

Author(s):

Aristides Isidoro Ferreira ◽

Joana Diniz Esteves

Keyword(s):

Gender Differences ◽

Design Methodology ◽

Internet Use ◽

The Internet ◽

Content Type ◽

Future Studies ◽

Work Related ◽

Phone Calls ◽

Working Day ◽

The Relationship

Purpose – Activities such as making personal phone calls, surfing on the internet, booking personal appointments or chatting with colleagues may or may not deviate attentions from work. With this in mind, the purpose of this paper is to examine gender differences and motivations behind personal activities employees do at work, as well as individuals’ perception of the time they spend doing these activities. Design/methodology/approach – Data were obtained from 35 individuals (M age=37.06 years; SD=7.80) from a Portuguese information technology company through an ethnographic method including a five-day non-participant direct observation (n=175 observations) and a questionnaire with open-ended questions. Findings – Results revealed that during a five-working-day period of eight hours per day, individuals spent around 58 minutes doing personal activities. During this time, individuals engaged mainly in socializing through conversation, internet use, smoking and taking coffee breaks. Results revealed that employees did not perceive the time they spent on non-work realted activities accurately, as the values of these perceptions were lower than the actual time. Moreover, through HLM, the findings showed that the time spent on conversation and internet use was moderated by the relationship between gender and the leisure vs home-related motivations associated with each personal activity developed at work. Originality/value – This study contributes to the literature on human resource management because it reveals how employees often perceive the time they spend on non-work related activities performed at work inaccurately. This study highlights the importance of including individual motivations when studying gender differences and personal activities performed at work. The current research discusses implications for practitioners and outlines suggestions for future studies.

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The optimism-pessimism ratio as predictor of employee creativity: the promise of duality

European Journal of Innovation Management ◽

10.1108/ejim-07-2017-0087 ◽

2018 ◽

Vol 21 (3) ◽

pp. 423-442 ◽

Cited By ~ 1

Author(s):

Arménio Rego ◽

Miguel Pina e Cunha ◽

Dálcio Reis Júnior ◽

Cátia Anastácio ◽

Moriel Savagnago

Keyword(s):

Cross Sectional ◽

Content Type ◽

Future Studies ◽

Positive Effects ◽

The Status ◽

Single Moment ◽

Quasi Experimental ◽

Creativity And Innovation ◽

The Relationship ◽

Practical Implications

Purpose The purpose of this paper is to study if the employees’ optimism-pessimism ratio predicts their creativity. Design/methodology/approach In total, 134 employees reported their optimism and pessimism, and the respective supervisors described the employees’ creativity. Findings The relationship between the optimism-pessimism ratio and creativity is curvilinear (inverted U-shaped); beyond a certain level of the optimism-pessimism ratio, the positive relationship between the ratio and creativity weakens, suggesting that the possible positive effects of (high) optimism may be weakened by a very low level of pessimism. Research limitations/implications Being cross-sectional, the study examines neither the causal links between the optimism-pessimism ratio and creativity nor other plausible causal links. The study was carried out at a single moment and did not capture the dynamics that occur over the course of time involving changes in optimism/pessimism and creativity. Future studies may adopt longitudinal or quasi-experimental designs. Practical implications Managers and organizations must consider that, even though positivity promotes creativity, some level of negativity may help positivity to produce creativity. Originality/value This study suggests that scholars who want to study the antecedents of creativity (and innovation) must be cautious in focusing only on the positive or the negative sides of individuals’ characteristics, and rather they must explore the interplay between both poles. Individuals may experience both positive and negative states/traits (Smith et al., 2016), and this both/and approach may impel them to think divergently, to challenge the status quo and to propose “out the box” and useful ideas.

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Integrated Theoretical Model of Smoking-Consumer Emotions and Research Outlook

Tobacco Regulatory Science ◽

10.18001/trs.7.4.2 ◽

2021 ◽

Vol 7 (4) ◽

pp. 251-263

Author(s):

Jiayi Du ◽

Xinkang Chen

Keyword(s):

Theoretical Model ◽

Literature Review ◽

Future Studies ◽

Moderating Variables ◽

Consumer Emotions ◽

The Future ◽

Consumer Emotion ◽

The Relationship

Objectives: Research on smoking-consumer emotions attracts increasing attention. Based on the literature review and analysis, this paper recognizes different definitions, categorizations, measurements of consumer emotions. Then the paper identifies the antecedent variables, moderating variables and outcome variables of consumer emotion and relevant emotion theories to explain the relationship and proposes an integrated theoretical model of consumer emotions. Finally, this paper talks about the future studies of consumer emotions on four aspects. This paper offers insights on the research of smoking-consumer emotions, theoretically and practically.

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