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1.
JMIR Ment Health ; 11: e50136, 2024 Apr 18.
Article in English | MEDLINE | ID: mdl-38635978

ABSTRACT

BACKGROUND: As depression is highly heterogenous, an increasing number of studies investigate person-specific associations of depressive symptoms in longitudinal data. However, most studies in this area of research conceptualize symptom interrelations to be static and time invariant, which may lead to important temporal features of the disorder being missed. OBJECTIVE: To reveal the dynamic nature of depression, we aimed to use a recently developed technique to investigate whether and how associations among depressive symptoms change over time. METHODS: Using daily data (mean length 274, SD 82 d) of 20 participants with depression, we modeled idiographic associations among depressive symptoms, rumination, sleep, and quantity and quality of social contacts as dynamic networks using time-varying vector autoregressive models. RESULTS: The resulting models showed marked interindividual and intraindividual differences. For some participants, associations among variables changed in the span of some weeks, whereas they stayed stable over months for others. Our results further indicated nonstationarity in all participants. CONCLUSIONS: Idiographic symptom networks can provide insights into the temporal course of mental disorders and open new avenues of research for the study of the development and stability of psychopathological processes.


Subject(s)
Depressive Disorder , Psychopathology , Humans , Depressive Disorder/epidemiology
2.
Chem Sci ; 15(9): 3300-3310, 2024 Feb 28.
Article in English | MEDLINE | ID: mdl-38425509

ABSTRACT

This work presents a spectroscopic and photocatalytic comparison of water splitting using yttrium iron garnet (Y3Fe5O12, YIG) and hematite (α-Fe2O3) photoanodes. Despite similar electronic structures, YIG significantly outperforms widely studied hematite, displaying more than an order of magnitude increase in photocurrent density. Probing the charge and spin dynamics by ultrafast, surface-sensitive XUV spectroscopy reveals that the enhanced performance arises from (1) reduced polaron formation in YIG compared to hematite and (2) an intrinsic spin polarization of catalytic photocurrents in YIG. Ultrafast XUV measurements show a reduction in the formation of surface electron polarons compared to hematite due to site-dependent electron-phonon coupling. This leads to spin polarized photocurrents in YIG where efficient charge separation occurs on the Td sub-lattice compared to fast trapping and electron/hole pair recombination on the Oh sub-lattice. These lattice-dependent dynamics result in a long-lived spin aligned hole population at the YIG surface, which is directly observed using XUV magnetic circular dichroism. Comparison of the Fe M2,3 and O L1-edges show that spin aligned holes are hybridized between O 2p and Fe 3d valence band states, and these holes are responsible for highly efficient, spin selective water oxidation by YIG. Together, these results point to YIG as a new platform for highly efficient, spin selective photocatalysis.

3.
Nano Lett ; 24(8): 2637-2642, 2024 Feb 28.
Article in English | MEDLINE | ID: mdl-38345784

ABSTRACT

Surface plasmon polaritons (SPPs) can confine and guide light in nanometer volumes and are ideal tools for achieving electric field enhancement and the construction of nanophotonic circuitry. The realization of the highest field strengths and fastest switching requires confinement also in the temporal domain. Here, we demonstrate a tapered plasmonic waveguide with an optimized grating structure that supports few-cycle surface plasmon polaritons with >70 THz bandwidth while achieving >50% light-field-to-plasmon coupling efficiency. This enables us to observe the─to our knowledge─shortest reported SPP wavepackets. Using time-resolved photoelectron microscopy with suboptical-wavelength spatial and sub-10 fs temporal resolution, we provide full spatiotemporal imaging of co- and counter-propagating few-cycle SPP wavepackets along tapered plasmonic waveguides. By comparing their propagation, we track the evolution of the laser-plasmon phase, which can be controlled via the coupling conditions.

4.
Multivariate Behav Res ; 59(3): 461-481, 2024.
Article in English | MEDLINE | ID: mdl-38247019

ABSTRACT

Network analysis has gained popularity as an approach to investigate psychological constructs. However, there are currently no guidelines for applied researchers when encountering missing values. In this simulation study, we compared the performance of a two-step EM algorithm with separated steps for missing handling and regularization, a combined direct EM algorithm, and pairwise deletion. We investigated conditions with varying network sizes, numbers of observations, missing data mechanisms, and percentages of missing values. These approaches are evaluated with regard to recovering population networks in terms of loss in the precision matrix, edge set identification and network statistics. The simulation showed adequate performance only in conditions with large samples (n≥500) or small networks (p = 10). Comparing the missing data approaches, the direct EM appears to be more sensitive and superior in nearly all chosen conditions. The two-step EM yields better results when the ratio of n/p is very large - being less sensitive but more specific. Pairwise deletion failed to converge across numerous conditions and yielded inferior results overall. Overall, direct EM is recommended in most cases, as it is able to mitigate the impact of missing data quite well, while modifications to two-step EM could improve its performance.


Subject(s)
Algorithms , Computer Simulation , Humans , Computer Simulation/statistics & numerical data , Data Interpretation, Statistical , Models, Statistical
5.
Science ; 380(6640): 59-63, 2023 Apr 07.
Article in English | MEDLINE | ID: mdl-37023199

ABSTRACT

Extreme ultraviolet (EUV) radiation is a key technology for material science, attosecond metrology, and lithography. Here, we experimentally demonstrate metasurfaces as a superior way to focus EUV light. These devices exploit the fact that holes in a silicon membrane have a considerably larger refractive index than the surrounding material and efficiently vacuum-guide light with a wavelength of ~50 nanometers. This allows the transmission phase at the nanoscale to be controlled by the hole diameter. We fabricated an EUV metalens with a 10-millimeter focal length that supports numerical apertures of up to 0.05 and used it to focus ultrashort EUV light bursts generated by high-harmonic generation down to a 0.7-micrometer waist. Our approach introduces the vast light-shaping possibilities provided by dielectric metasurfaces to a spectral regime that lacks materials for transmissive optics.

6.
Water Res ; 235: 119824, 2023 May 15.
Article in English | MEDLINE | ID: mdl-36913811

ABSTRACT

Aluminum salts are widely used to immobilize phosphorus (P) in lakes suffering from internal loading. However, longevity of treatments varies among lakes; some lakes eutrophy faster than others. We conducted biogeochemical investigations of sediments of a closed artificial Lake Barleber, Germany that was successfully remediated with aluminum sulfate in 1986. The lake became mesotrophic for almost 30 years; a rather rapid re-eutrophication took place in 2016 leading to massive cyanobacterial blooms. We quantified internal loading from sediment and analyzed two environmental factors that might have contributed to the sudden shift in trophic state. Increase in lake P concentration started in 2016, reaching 0.3 mg L-1, and remained elevated into the spring of 2018. Reducible P fraction in the sediment was 37 - 58% of total P, indicating a high potential for mobilization of benthic P during anoxia. Estimated P release from sediments for 2017 was approximately 600 kg for the whole lake. This is consistent with sediment incubation results; higher temperature (20°C) and anoxia contributed to release of P (27.9 ± 7.1 mg m-2 d-1, 0.94 ± 0.23 mmol m-2 d-1) to the lake, triggering re-eutrophication. Loss of aluminum P adsorption capacity together with anoxia and high water temperatures (organic matter mineralization) are major drivers of re-eutrophication. Accordingly, treated lakes at some time require a repeated aluminum treatment for sustaining acceptable water quality and we recommend regular sediment monitoring in treated lakes. This is crucial given the effects of climate warming on duration of stratification in lakes which may result in the need for treatment of many lakes.


Subject(s)
Aluminum , Lakes , Humans , Phosphorus/analysis , Geologic Sediments , Alum Compounds , Eutrophication , Hypoxia , Environmental Monitoring
7.
Environ Sci Technol ; 57(9): 4003-4013, 2023 03 07.
Article in English | MEDLINE | ID: mdl-36802563

ABSTRACT

Phosphorus (P) precipitation is among the most effective treatments to mitigate lake eutrophication. However, after a period of high effectiveness, studies have shown possible re-eutrophication and the return of harmful algal blooms. While such abrupt ecological changes were attributed to the internal P loading, the role of lake warming and its potential synergistic effects with internal loading, thus far, has been understudied. Here, in a eutrophic lake in central Germany, we quantified the driving mechanisms of the abrupt re-eutrophication and cyanobacterial blooms in 2016 (30 years after the first P precipitation). A process-based lake ecosystem model (GOTM-WET) was established using a high-frequency monitoring data set covering contrasting trophic states. Model analyses suggested that the internal P release accounted for 68% of the cyanobacterial biomass proliferation, while lake warming contributed to 32%, including direct effects via promoting growth (18%) and synergistic effects via intensifying internal P loading (14%). The model further showed that the synergy was attributed to prolonged lake hypolimnion warming and oxygen depletion. Our study unravels the substantial role of lake warming in promoting cyanobacterial blooms in re-eutrophicated lakes. The warming effects on cyanobacteria via promoting internal loading need more attention in lake management, particularly for urban lakes.


Subject(s)
Cyanobacteria , Lakes , Lakes/microbiology , Ecosystem , Eutrophication , Nutrients , Harmful Algal Bloom , Phosphorus/analysis , China
8.
J Clin Psychol Med Settings ; 30(1): 153-168, 2023 03.
Article in English | MEDLINE | ID: mdl-35576086

ABSTRACT

We predicted that chronic pain patients have a more negative stress mindset and a lower level of social identification than people without chronic pain and that this, in turn, influences well-being through less adaptive coping. 1240 participants (465 chronic pain patients; 775 people in the control group) completed a cross-sectional online-survey. Chronic pain patients had a more negative stress mindset and a lower level of social identification than people without chronic pain. However, a positive stress mindset was linked to better well-being and fewer depressive symptoms, through the use of the adaptive coping behaviors positive reframing and active coping. A higher level of social identification did not impact well-being or depression through the use of instrumental and emotional support coping, but through the more frequent use of positive reframing and active coping. For chronic pain therapy, we propose including modules that foster social identification and a positive stress mindset.


Subject(s)
Adaptation, Psychological , Chronic Pain , Depression , Health , Patients , Social Identification , Stress, Psychological , Humans , Male , Female , Adolescent , Young Adult , Adult , Middle Aged , Aged , Chronic Pain/complications , Chronic Pain/psychology , Patients/psychology , Depression/complications , Depression/psychology , Stress, Psychological/complications , Stress, Psychological/psychology , Cross-Sectional Studies , Internet , Surveys and Questionnaires , Models, Psychological , Mediation Analysis , Social Support
9.
PLoS One ; 17(8): e0272938, 2022.
Article in English | MEDLINE | ID: mdl-36006898

ABSTRACT

A large body of research has examined the link between personality and face-to-face (FtF) communication knowledge, skills, abilities, and other characteristics (KSAOs). With the rise of digital media, text-based computer-mediated (CM) communication KSAOs have gained increasing attention. We conducted two studies to investigate how personality relates to KSAOs in the different contexts of FtF and CM communication. Contrasting perspectives hypothesize that the results in the FtF and CM contexts would be very similar or distinctly different. In Study 1 (n = 454), an online panel study, the Big Five personality dimensions were assessed and their relationships to FtF and CM communication KSAOs were investigated. Structural equation models and relative weight regression analyses showed that these personality dimensions, mostly extraversion and neuroticism, explained more variance in FtF as compared to CM communication KSAOs. Study 2 (n = 173), conducted in a laboratory context, showed similar results compared to Study 1. In addition, when the Big Five personality dimensions were assessed with a CM frame of reference, more variance was explained in CM than in FtF communication KSAOs. These results point to the importance of considering context effects in communication and in personality research: FtF and CM communication KSAOs need to be differentiated. If not properly contextualized, the relevance of personality and communication competencies in predicting criteria may be underestimated due to contextual mismatches.


Subject(s)
Internet , Personality , Communication , Computers , Extraversion, Psychological
10.
Assessment ; 29(3): 467-487, 2022 04.
Article in English | MEDLINE | ID: mdl-33371717

ABSTRACT

While Diagnostic and Statistical Manual of Mental Disorders-Fifth edition (DSM-5) Section III and ICD-11 (International Classification of Diseases 11th-Revision) both allow for dimensional assessment of personality pathology, the models differ in the definition of maladaptive traits. In this study, we pursued the goal of developing a short and reliable assessment for maladaptive traits, which is compatible with both models, using the item pool of the Personality Inventory for DSM-5 (PID-5). To this aim, we applied ant colony optimization algorithms in English- and German-speaking samples comprising a total N of 2,927. This procedure yielded a 34-item measure with a hierarchical latent structure including six maladaptive trait domains and 17 trait facets, the "Personality Inventory for DSM-5, Brief Form Plus" (PID5BF+). While latent structure, reliability, and criterion validity were ascertained in the original and in two separate validation samples (n = 849, n = 493) and the measure was able to discriminate personality disorders from other diagnoses in a clinical subsample, results suggest further modifications for capturing ICD-11 Anankastia.


Subject(s)
International Classification of Diseases , Personality , Algorithms , Diagnostic and Statistical Manual of Mental Disorders , Humans , Personality Inventory , Reproducibility of Results
11.
Patient Educ Couns ; 105(7): 2328-2337, 2022 07.
Article in English | MEDLINE | ID: mdl-34823923

ABSTRACT

OBJECTIVE: To evaluate the real-time usage of krankheitserfahrungen.de, a website providing scientifically collected and analyzed experiences of persons with various chronic illnesses. METHODS: Web analytics of website use of www.krankheitserfahrungen.de in 2016. Qualitative content analysis of the 150 most and least opened video/audio clip titles in 2018-19. RESULTS: In 2016, krankheitserfahrungen.de had 19,703 unique visits, of which 3925 were returning visits. Between new and returning visits, the latter were characterized by more actions and more time spent on the website. Thematic pages were clicked more often during new visits and person pages were more frequented during returning visits. In 2018-19, video/audio clip titles related to topics around uncertainties and/or decision making were most often clicked, whereas the least clicked clips dealt with topics like illness management, problem-solving, giving advice to others and emotionally difficult topics such as suffering, death and burden for the family. CONCLUSION: A website with balanced, scientifically collected and analyzed patient experiences attracts a sufficient number of users and is used for further explorations. PRACTICE IMPLICATIONS: Using multiple formats, broad topics and diverse personal experiences being accessible through themes or persons is necessary when a scientifically based website on patients' experiences is designed.


Subject(s)
Internet , Chronic Disease , Germany , Humans
12.
Water Res ; 190: 116681, 2021 Feb 15.
Article in English | MEDLINE | ID: mdl-33310439

ABSTRACT

In temperate lakes, it is generally assumed that light rather than temperature constrains phytoplankton growth in winter. Rapid winter warming and increasing observations of winter blooms warrant more investigation of these controls. We investigated the mechanisms regulating a massive winter diatom bloom in a temperate lake. High frequency data and process-based lake modeling demonstrated that phytoplankton growth in winter was dually controlled by light and temperature, rather than by light alone. Water temperature played a further indirect role in initiating the bloom through ice-thaw, which increased light exposure. The bloom was ultimately terminated by silicon limitation and sedimentation. These mechanisms differ from those typically responsible for spring diatom blooms and contributed to the high peak biomass. Our findings show that phytoplankton growth in winter is more sensitive to temperature, and consequently to climate change, than previously assumed. This has implications for nutrient cycling and seasonal succession of lake phytoplankton communities. The present study exemplifies the strength in integrating data analysis with different temporal resolutions and lake modeling. The new lake ecological model serves as an effective tool in analyzing and predicting winter phytoplankton dynamics for temperate lakes.


Subject(s)
Diatoms , Lakes , Biomass , Eutrophication , Phytoplankton , Seasons
13.
Sociol Health Illn ; 42(6): 1359-1378, 2020 07.
Article in English | MEDLINE | ID: mdl-32614484

ABSTRACT

The concept of biographical disruption has been used to explain the experience of a cancer diagnosis. Studies on cancer experience increasingly suggest that people diagnosed in older age may not have such disruptive experiences. Prostate cancer is diagnosed more often in older men and is often considered a disease of old age; furthermore, the signs of illness in prostate cancer and the signs of ageing might become convoluted. With this in mind, this paper aims to explore how 42 men with prostate cancer who participated in an interview study respond to and make sense of bodily changes. The sample was selected using a maximum variation strategy in order to describe a range of possible experiences with prostate cancer. Analysis was conducted thematically. The men's narratives tell of the constant process of dealing with ageing-related and/or cancer-related changes to both their bodies and their social interactions, and their struggle to disentangle the related effects of ageing and/or cancer on their bodies. We describe how men "muddle through" problems of urinary leakage, potency and loss of libido. We then identify how men attributed changes as part of ageing and/or cancer to (better) manage the experiences of loss.


Subject(s)
Prostatic Neoplasms , Adaptation, Psychological , Aged , Aging , Germany , Humans , Male , Narration
14.
Nat Commun ; 11(1): 430, 2020 Jan 22.
Article in English | MEDLINE | ID: mdl-31969568

ABSTRACT

The sub-cycle interaction of light and matter is one of the key frontiers of inquiry made accessible by attosecond science. Here, we show that when light excites a pair of charge carriers inside of a solid, the transition probability is strongly localized to instants slightly after the extrema of the electric field. The extreme temporal localization is utilized in a simple electronic circuit to record the waveforms of infrared to ultraviolet light fields. This form of petahertz-bandwidth field metrology gives access to both the modulated transition probability and its temporal offset from the laser field, providing sub-fs temporal precision in reconstructing the sub-cycle electronic response of a solid state structure.

15.
Assessment ; 27(5): 903-920, 2020 07.
Article in English | MEDLINE | ID: mdl-30198314

ABSTRACT

Planned missing data (PMD) designs are an elegant way to incorporate expensive gold standard methods (e.g., biomarker) and cheaper but systematically biased methods (e.g., questionnaires) in research designs while ensuring high statistical power and low research costs. This article outlines a PMD design with one expensive gold standard and two cheap but biased methods (three-method measurement [3-MM] design). The cost effectiveness of different 3-MM-PMD designs is investigated and compared with the cost effectiveness of corresponding same-price two-method measurement designs using a simulation study. The results underline that PMD designs yield higher statistical power compared with complete data designs in a wide variety of conditions. Adding a second cheap method to the measurement model (i.e., using a 3-MM-PMD design) can increase the statistical power of the research design even further while keeping costs constant, when the additional measure is inexpensive, shares only small amounts of bias variance with the initial cheap measure, and when the gold standard measure is highly expensive compared with the cheap measures. Recommendations as well as a computer program for finding the optimal research design are provided.


Subject(s)
Research Design , Software , Bias , Computer Simulation , Humans
16.
Appl Psychol Health Well Being ; 11(3): 522-542, 2019 11.
Article in English | MEDLINE | ID: mdl-31231970

ABSTRACT

BACKGROUND: Existing evidence indicates that social support may enhance recipients' self-efficacy (enabling hypothesis) or that self-efficacy facilitates support receipt (cultivation hypothesis). However, less is known about the time-lagged support-self-efficacy relationship in couples. Our aim was to disentangle reciprocal interrelations among stable and time-varying components of support provision and self-efficacy in couples over time. METHODS: We conducted secondary analyses of a published randomised controlled trial with six assessments, spanning 1 year and N = 338 heterosexual couples (age range: 18-80 years). Women's and men's reports on physical activity-specific provided support and physical activity-specific self-efficacy were analysed. RESULTS: Based on the actor-partner interdependence model, we compared nested random intercepts cross-lagged panel models. The final model revealed no gender effects. Stable levels of both partners' support provision and self-efficacy were positively associated. At the time-varying level, one partner's self-efficacy predicted the other partner's support provision later on. No lagged-association emerged for the opposite predictive direction. CONCLUSIONS: Partners' stable shares of provided support and self-efficacy were interrelated, whereas higher time-varying self-efficacy of one partner seemed to activate support provision from the other partner, confirming the cultivation hypothesis but not the enabling hypothesis.


Subject(s)
Interpersonal Relations , Self Efficacy , Sexual Partners/psychology , Social Support , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Longitudinal Studies , Male , Middle Aged , Surveys and Questionnaires , Young Adult
17.
Nature ; 571(7764): 240-244, 2019 07.
Article in English | MEDLINE | ID: mdl-31243366

ABSTRACT

The enigmatic interplay between electronic and magnetic phenomena observed in many early experiments and outlined in Maxwell's equations propelled the development of modern electromagnetism1. Today, the fully controlled evolution of the electric field of ultrashort laser pulses enables the direct and ultrafast tuning of the electronic properties of matter, which is the cornerstone of light-wave electronics2-7. By contrast, owing to the lack of first-order interaction between light and spin, the magnetic properties of matter can only be affected indirectly and on much longer timescales, through a sequence of optical excitations and subsequent rearrangement of the spin structure8-16. Here we introduce the regime of ultrafast coherent magnetism and show how the magnetic properties of a ferromagnetic layer stack can be manipulated directly by the electric-field oscillations of light, reducing the magnetic response time to an external stimulus by two orders of magnitude. To track the unfolding dynamics in real time, we develop an attosecond time-resolved magnetic circular dichroism detection scheme, revealing optically induced spin and orbital momentum transfer in synchrony with light-field-driven coherent charge relocation17. In tandem with ab initio quantum dynamical modelling, we show how this mechanism enables the simultaneous control of electronic and magnetic properties that are essential for spintronic functionality. Our study unveils light-field coherent control of spin dynamics and macroscopic magnetic moments in the initial non-dissipative temporal regime and establishes optical frequencies as the speed limit of future coherent spintronic applications, spin transistors and data storage media.

18.
Br J Math Stat Psychol ; 72(2): 294-315, 2019 05.
Article in English | MEDLINE | ID: mdl-30693481

ABSTRACT

When multisource feedback instruments, for example, 360-degree feedback tools, are validated, multilevel structural equation models are the method of choice to quantify the amount of reliability as well as convergent and discriminant validity. A non-standard multilevel structural equation model that incorporates self-ratings (level-2 variables) and others' ratings from different additional perspectives (level-1 variables), for example, peers and subordinates, has recently been presented. In a Monte Carlo simulation study, we determine the minimal required sample sizes for this model. Model parameters are accurately estimated even with the smallest simulated sample size of 100 self-ratings and two ratings of peers and of subordinates. The precise estimation of standard errors necessitates sample sizes of 400 self-ratings or at least four ratings of peers and subordinates. However, if sample sizes are smaller, mainly standard errors concerning common method factors are biased. Interestingly, there are trade-off effects between the sample sizes of self-ratings and others' ratings in their effect on estimation bias. The degree of convergent and discriminant validity has no effect on the accuracy of model estimates. The χ2 test statistic does not follow the expected distribution. Therefore, we suggest using a corrected level-specific standardized root mean square residual to analyse model fit and conclude with further recommendations for applied organizational research.


Subject(s)
Multilevel Analysis , Psychometrics/methods , Computer Simulation , Formative Feedback , Humans , Monte Carlo Method , Reproducibility of Results , Sample Size
19.
Front Psychol ; 9: 2399, 2018.
Article in English | MEDLINE | ID: mdl-30559697

ABSTRACT

The New Year's Eve 2015 mass sexual assaults in Germany led to a broader debate about whether the perpetrators, most of them self-identifying as Muslims, were encouraged to such acts by particularly sexist attitudes toward girls and women. Here, we argue that it is not the specific religious affiliation of individuals per se that predicts sexism. Rather it should be the extent to which they are involved in their religion, i.e., their religiosity and their endorsement of religious fundamentalism. In line with the theory of ambivalent sexism, we distinguish hostile and benevolent sexism, while controlling for right-wing authoritarianism and social dominance orientation. In two Pilot Studies, we explored differences in ambivalent sexism (a) between male and female individuals of Muslim faith, Christian faith, Muslim faith, Christian faith, and no religious affiliation residing in Germany, while at the same time (b) differentiating between sexism directed toward girls and sexism directed toward women. In our Main Study, we tested the interrelations between religiosity, religious fundamentalism, and ambivalent sexism in our religious subsamples of male Christians, female Christians, male Muslims, and female Muslims using a multigroup multivariate moderated mediation analysis. In all three studies, Muslims were more religious, endorsed religious fundamentalism more strongly, and held stronger benevolent sexist beliefs toward girls and women as well as stronger hostile sexist beliefs toward women than Christians and non-religious participants. In our Main Study, with female Christians as the reference group, male Muslims' stronger benevolent and hostile sexist beliefs toward girls were mediated by religiosity and fundamentalism. Female Muslims' stronger endorsement of benevolent sexism toward girls could be explained by their higher level of fundamentalism. While our findings show that differences in ambivalent sexism between religious groups were partly due to different levels of religiosity and fundamentalism, they also suggest that there are factors other than those investigated in our studies responsible for male Muslims' particularly strong sexism. We discuss specific contents of Islamic religious teachings and honor beliefs as possible causes to be investigated further in future research.

20.
Sci Total Environ ; 640-641: 217-231, 2018 Nov 01.
Article in English | MEDLINE | ID: mdl-29859438

ABSTRACT

Mine pit lakes may develop at mine closure when mining voids extend below groundwater levels and fill with water. Acid and metalliferous drainage (AMD) and salinity are common problems for pit lake water quality. Contaminated pit lake waters can directly present significant risk to both surrounding and regional communities and natural environmental values and limit beneficial end use opportunities. Pit lake waters can also discharge into surface and groundwater; or directly present risks to wildlife, stock and human end users. Riverine flow-through is increasingly proposed to mitigate or remediate pit lake water contamination using catchment scale processes. This paper presents the motivation and key processes and considerations for a flow-through pit lake closure strategy. International case studies as precedent and lessons for future application are described from pit lakes that use or propose flow-through as a key component of their mine closure design. Chemical and biological processes including dilution, absorption and flocculation and sedimentation can sustainably reduce pit lake contaminant concentrations to acceptable levels for risk and enable end use opportunities to be realised. Flow-through may be a valid mine closure strategy for pit lakes with poor water quality. However, maintenance of existing riverine system values must be foremost. We further suggest that decant river water quality may, in some circumstances, be improved; notably in examples of meso-eutrophic river waters flowing through slightly acidic pit lakes. Flow-through closure strategies must be scientifically justifiable and risk-based for both lake and receptors potentially affected by surface and groundwater transport. Due to the high-uncertainty associated with this complex strategy, biotic and physico-chemical attributes of both inflow and decant river reaches as well as lake should be well monitored. Monitoring should directly feed into an adaptive management framework discussed with key stakeholders with validation of flow-through as a sustainable strategy prior to mine relinquishment.

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