Disconnected active layers and unfrozen permafrost: A discussion of permafrost-related terms and definitions.

Permafrost is ground that remains at or below 0 °C for two or more consecutive years. It is overlain by an active layer which thaws and freezes annually. The difference between these definitions - the active layer based on pore water phase and permafrost based on soil temperature - leads to challenges when monitoring and modelling permafrost environments. Contrary to its definition, the key properties of permafrost including hardness, bearing capacity, permeability, unfrozen water content, and energy content, depend primarily on the ice content of permafrost and not its temperature. Temperature-based measurements in permafrost systems often overlook key features, e.g. taliks and cryopegs, and comparisons between measured and modelled systems can differ energetically by up to 90 % while reporting the same temperature. Due to the shortcomings of the temperature-based definition, it is recommended that an estimate of ice content be reported alongside temperature in permafrost systems for both in-situ measurements and modelling applications. PLAIN LANGUAGE SUMMARY: Permafrost is ground that remains at or below 0 °C for two or more consecutive years. Above it sits an active layer which thaws and freezes annually (meaning that the water in the ground changes to ice each winter). The difference between these definitions - the active layer based on the state or water in the ground and permafrost based on ground temperature - leads to challenges when measuring (in the field) and modelling (using computers) permafrost environments. In addition to these challenges, the key properties of permafrost including its ability to support infrastructure, convey water, and absorb energy depend more on its ice content than its temperature. Due to the shortcomings of the temperature-based definition, it is recommended that an estimate of ice content be reported alongside temperature in permafrost systems for both field measurements and modelling applications.

Using Browser Data to Understand Desires to Spend Time Online.

There is growing recognition that many people feel the need to regulate their use of the internet and other digital technologies to support their wellbeing. In this study, we used Mozilla Firefox browser telemetry to investigate the role played by various usage factors in desires to regulate time spent online. In particular, we investigated how six metrics pertaining to time spent on the internet, and the diversity and intensity of use, predict participants' (n = 8,094) desires to spend more or less time online. Across all six metrics, we did not find evidence for a relationship between browser usage metrics and participants wanting to spend more or less time online. This finding was robust across various analytical pathways. The study highlights a number of considerations and concerns that need to be addressed in future industry-academia collaborations that draw on trace data or usage telemetry.

Persulfate-based ISCO for field-scale remediation of NAPL-contaminated soil: Column experiments and modeling.

An experimental and computational investigation of in situ chemical oxidation (ISCO) of weathered diesel fuel in soil columns was undertaken to validate a reactive-transport model capable of predicting contaminant mass reduction from a residual source zone. Reactivity tests with contaminated groundwater in batch reactors were used to estimate a priori the kinetic parameters of a phenomenological model of the oxidation of petroleum hydrocarbon (PHC) mixture fractions. The transport model, which incorporated groundwater flow, dissolution of main PHC fractions, and homogeneous reaction in the aqueous phase, was subsequently validated against experimental data of ISCO in soil columns using repetitive treatments with unactivated and alkaline-activated persulfate. No significant effect of the initial concentration of persulfate on the remediation performance was observed in the batch system, but alkaline activation significantly improved performance. The alkaline-activated persulfate treatment achieved ∼80% removal of the initial NAPL mass in soil columns. The combination of models and experiments described herein should enable the rational design of field-scale advanced oxidation strategies for the removal of weathered petroleum hydrocarbons. This expectation was supported by a comprehensive demonstration study at a historical site contaminated by weathered diesel fuel present as a residual source within the soil and dissolved within groundwater.

Sleep influences daily suicidal ideation through affective reactivity to interpersonal events among high-risk adolescents and young adults.

BACKGROUND: Identifying proximal risk factors for suicidal ideation that are modifiable and relevant for adolescents and young adults is critical for suicide prevention. This study used an intensive monitoring approach to examine whether objectively- and subjectively- measured sleep characteristics predict next-day suicidal ideation occurrence and intensity through affective reactivity to interpersonal events in young people at high risk for suicide. METHODS: Participants included 59 (13-23 years; 76% White; 75% female) adolescents and young adults undergoing intensive outpatient program treatment for depression and suicidality. Participants completed daily ratings of suicidal ideation, sleep quality, and affective reactivity to positive and negative interpersonal events for up to 3 months (M = 56 days, SD = 24.13). Actigraphy captured behavioral sleep duration and timing. Multilevel modeling was used to evaluate within-person fluctuations in sleep and affective reactivity as predictors of suicidal ideation, and multilevel mediation tested the indirect effects of sleep on suicidal ideation via affective reactivity to interpersonal events. RESULTS: Results indicate significant indirect effects of objectively measured sleep duration and subjective sleep quality on next-day suicidal ideation via affective reactivity to negative and positive interpersonal events, respectively. Shorter-than-usual sleep predicted the presence and intensity of next-day suicidal ideation via heightened affective reactivity to negative interpersonal events. Worse sleep quality than usual predicted next-day suicidal ideation via reduced affective reactivity to positive interpersonal events. CONCLUSIONS: Affectivity reactivity is a proximal mechanism through which sleep indices may influence risk for suicidal thinking on a daily basis. Findings highlight the utility of targeting sleep and emotion regulation in suicide prevention among adolescents and young adults at high-risk for suicide.

DNA sequencing, microbial indicators, and the discovery of buried kimberlites.

Population growth and technological advancements are placing growing demand on mineral resources. New and innovative exploration technologies that improve detection of deeply buried mineralization and host rocks are required to meet these demands. Here we used diamondiferous kimberlite ore bodies as a test case and show that DNA amplicon sequencing of soil microbial communities resolves anomalies in microbial community composition and structure that reflect the surface expression of kimberlites buried under 10 s of meters of overburden. Indicator species derived from laboratory amendment experiments were employed in an exploration survey in which the species distributions effectively delineated the surface expression of buried kimberlites. Additional indicator species derived directly from field observations improved the blind discovery of kimberlites buried beneath similar overburden types. Application of DNA sequence-based analyses of soil microbial communities to mineral deposit exploration provides a powerful illustration of how genomics technologies can be leveraged in the discovery of critical new resources.

Does Objectively Measured Social-Media or Smartphone Use Predict Depression, Anxiety, or Social Isolation Among Young Adults?

Despite a plethora of research, the link between digital technology use and psychological distress among young adults remains inconclusive. Findings in this area are typically undermined by methodological limitations related to measurement, study design, and statistical analysis. Addressing these limitations, we examined the prospective, within-person associations between three aspects of objectively-measured digital technology use (smartphone use duration and frequency; social media use duration) and three aspects of psychological distress (depression, anxiety, and social isolation) among a sample of young adults (N = 384). Across 81 different model specifications, we found that most within-person prospective effects between digital technology use and psychological distress were statistically non-significant and all were very small-even the largest effects were unlikely to register a meaningful impact on a person's psychological distress. In post hoc subgroup analyses, we found scant evidence for the claim that digital technology use is more harmful for women and/or younger people.

Animal board invited review: Factors affecting the early growth and development of gilt progeny compared to sow progeny.

Progeny born to primiparous sows farrowing their first litter, often called gilt progeny (GP), are typically characterised by their poorer overall production performance than progeny from multiparous sows (sow progeny; SP). Gilt progeny consistently grow slower, are born and weaned lighter, and have higher postweaning illness and mortality rates than SP. Collectively, their poorer performance culminates in a long time to reach market weight and, ultimately, reduced revenue. Due to the high replacement rates of sows, the primiparous sow and her progeny represent a large proportion of the herd resulting in a significant loss for the pig industry. While the reasons for poorer performance are complex and multifaceted, they may largely be attributed to the immature age at which gilts are often mated and the significant impact of this on their metabolism during gestation and lactation. As a result, this can have negative consequences on the piglet itself. To improve GP performance, it is crucial to understand the biological basis for differences between GP and SP. The purpose of this review is to summarise published literature investigating differences in growth performance and health status between GP and SP. It also examines the primiparous sow during gestation and lactation and how the young sow must support her own growth while supporting the metabolic demands of her pregnancy and the growth and development of her litter. Finally, the underlying physiology of GP is discussed in terms of growth and development in utero, the neonatal period, and the early development of the gastrointestinal tract. The present review concludes that there are a number of interplaying factors relating to the anatomy and physiology of the primiparous sow and of GP themselves. The studies presented herein strongly suggest that poor support of piglet growth in utero and reduced colostrum and milk production and consumption are largely responsible for the underperformance of GP. It is therefore recommended that future management strategies focus on supporting the primiparous sow during gestation and lactation, increasing the preweaning growth of GP to improve their ability to cope with the stressors of weaning, selection of reproductive traits such as uterine capacity to improve birth weights and ultimately GP performance, and finally, increase the longevity of sows to reduce the proportion of GP entering the herd.

Social media and well-being: A methodological perspective.

Due to the methodological challenges inherent in studying social media use (SMU), as well as the methodological choices that have shaped research into the effects of SMU on well-being, clear conclusions regarding relationships between SMU and well-being remain elusive. We provide a review of five methodological developments poised to provide increased understanding in this domain: (a) increased use of longitudinal and experimental designs; (b) the adoption of behavioural (rather than self-report) measures of SMU; (c) focusing on more nuanced aspects of SMU; (d) embracing effect heterogeneity; and (e) the use of formal modelling and machine learning. We focus on how these advances stand to bring us closer to understanding relations between SMU and well-being, as well as the challenges associated with these developments.

Simulating the cumulative effects of potential open-pit mining and climate change on streamflow and water quality in a mountainous watershed.

Land use and climate change effects on water quality and water quantity are well documented globally. Most studies evaluate individual factors and effects, without considering the interrelationships between land use, climate, water quality, and water quantity. This study provides an integrated assessment of the cumulative effects of climate change and potential open-pit coal mining on streamflow and water quality in the Oldman River Basin, Alberta, Canada. A hydrological model was developed that incorporates estimates of future selenium loading, water use, and projected changes in air temperature and precipitation to evaluate changes in water quantity and quality. Model results indicate that estimated selenium concentrations, absent any attenuation, are likely to be substantially above most water quality guidelines and strong reliance on mitigation technologies would be required to maintain adequate water quality in the watershed if mine development were to take place. Streamflow is sensitive to changes in climatic conditions, and modelling results suggest there are likely to be increases in winter flow, earlier peak flow, and reductions in flow during the summer and fall months under the climate change scenarios. These changes can have direct impacts on the degree of selenium dilution and more generally on aquatic habitat, ecosystem health, and socioeconomic needs. This study highlights that water management decisions may mis-evaluate the risks and tradeoffs of future mine development if they fail to adequately consider climate change and changing streamflow regimes and their indirect effects on water quality.

A systematic review and meta-analysis of discrepancies between logged and self-reported digital media use.

There is widespread public and academic interest in understanding the uses and effects of digital media. Scholars primarily use self-report measures of the quantity or duration of media use as proxies for more objective measures, but the validity of these self-reports remains unclear. Advancements in data collection techniques have produced a collection of studies indexing both self-reported and log-based measures. To assess the alignment between these measures, we conducted a pre-registered meta-analysis of this research. Based on 106 effect sizes, we found that self-reported media use correlates only moderately with logged measurements, that self-reports were rarely an accurate reflection of logged media use and that measures of problematic media use show an even weaker association with usage logs. These findings raise concerns about the validity of findings relying solely on self-reported measures of media use.

Computational fluid dynamic modelling of maxillary sinus irrigation after maxillary antrostomy and modified endoscopic medial maxillectomy.

OBJECTIVE: For recalcitrant chronic maxillary sinusitis, modified endoscopic medial maxillectomy has been shown to be clinically beneficial after failed maxillary antrostomy as endoscopic medial maxillectomy may offer improved topical therapy delivery. This study compared irrigation patterns after maxillary antrostomy versus endoscopic medial maxillectomy, using computational fluid dynamic modelling. CASE REPORT: A 54-year-old female with left chronic maxillary sinusitis underwent maxillary antrostomy, followed by endoscopic medial maxillectomy. Computational fluid dynamic models were created after each surgery and used to simulate irrigations. RESULTS: After maxillary antrostomy, irrigation penetrated the maxillary sinus at 0.5 seconds, initially contacting the posterior wall. The maxillary sinus was half-filled at 2 seconds, and completely filled at 4 seconds. After endoscopic medial maxillectomy, irrigation penetrated the maxillary sinus at 0.5 seconds and immediately contacted all maxillary sinus walls. The maxillary sinus was completely filled by 2 seconds. CONCLUSION: Computational fluid dynamic modelling demonstrated that endoscopic medial maxillectomy allowed faster, more forceful irrigation to all maxillary sinus walls compared with maxillary antrostomy.

Objectively measured digital technology use during the COVID-19 pandemic: Impact on depression, anxiety, and suicidal ideation among young adults.

BACKGROUND: Research suggests that the disruptions introduced by the COVID-19 pandemic have led to increased psychological distress and time spent on digital technology among young people, thus intensifying pre-pandemic concerns regarding the putative effects of digital technology use on mental health. To robustly examine whether increases in digital technology use are associated with increases in psychological distress during the pandemic it is crucial to (1) collect objective data on digital technology use and (2) account for potential confounding caused by pandemic-related stressors. METHODS: We conducted a four-wave panel study of U.S. young adults (N=384; Mage = 24.5 ± 5.1; 57% female) from August-November of 2020. Participants provided screenshots of their iPhone "Screen Time" application and completed measures assessing current mental health status (depression, anxiety, and suicidal ideation) and pandemic-related impacts on well-being. We used random-intercept multilevel models to examine the within- and between-person associations between mental health, objective digital technology use, and pandemic-related stressors. RESULTS: Multilevel analyses revealed that none of the objectively-measured digital technology use variables were positively associated with depression, anxiety, or suicidal ideation at the within- or between-person levels. In contrast, pandemic-related impacts on mental health had by far the largest effects on depression, anxiety, and suicidal ideation. LIMITATIONS: The convenience-based sample and use of single-item measures of pandemic-related impacts are limitations of the study. CONCLUSIONS: Current speculations about the direct harms of digital technology use on mental health may be unfounded and risk diverting attention from a more likely cause: pandemic-related distress.

A Bayesian multilevel analysis of the longitudinal associations between relationship quality and suicidal ideation and attempts among youth with bipolar disorder.

BACKGROUND: Youth with bipolar disorder (BD) are at high risk for suicidal thoughts and behaviors and frequently experience interpersonal impairment, which is a risk factor for suicide. Yet, no study to date has examined the longitudinal associations between relationship quality in family/peer domains and suicidal thoughts and behaviors among youth with BD. Thus, we investigated how between-person differences - reflecting the average relationship quality across time - and within-person changes, reflecting recent fluctuations in relationship quality, act as distal and/or proximal risk factors for suicidal ideation (SI) and suicide attempts. METHODS: We used longitudinal data from the Course and Outcome of Bipolar Youth Study (N = 413). Relationship quality variables were decomposed into stable (i.e., average) and varying (i.e., recent) components and entered, along with major clinical covariates, into separate Bayesian multilevel models predicting SI and suicide attempt. We also examined how the relationship quality effects interacted with age and sex. RESULTS: Poorer average relationship quality with parents (ß = -.33, 95% Bayesian highest density interval (HDI) [-0.54, -0.11]) or friends (ß = -.33, 95% HDI [-0.55, -0.11]) was longitudinally associated with increased risk of SI but not suicide attempt. Worsening recent relationship quality with parents (ß = -.10, 95% HDI [-0.19, -0.03]) and, to a lesser extent, friends (ß = -.06, 95% HDI [-0.15, 0.03]) was longitudinally associated with increased risk of SI, but only worsening recent relationship quality with parents was also associated with increased risk of suicide attempt (ß = -.15, 95% HDI [-0.31, 0.01]). The effects of certain relationship quality variables were moderated by gender but not age. CONCLUSIONS: Among youth with BD, having poorer average relationship quality with peers and/or parents represents a distal risk factor for SI but not suicide attempts. Additionally, worsening recent relationship quality with parents may be a time-sensitive indicator of increased risk for SI or suicide attempt.

Social Media Use and Deliberate Self-Harm Among Youth: A Systematized Narrative Review.

BACKGROUND: Suicide is now the 2nd leading cause of death among adolescents and young adults. Social media's influence on youth suicidal risk or attenuation of risk is a novel and rapidly expanding topic of research that requires attention from a broad range of mental health services professionals. We aimed to provide an updated review of social media-related risk and protective factors to youth deliberate-self harm (DSH) to guide mental health services professionals in offering care and support to youth vulnerable to suicide. METHODS: Studies on which primary research was conducted that evaluated young people's use of social media platforms related to DSH were systematically searched via Scopus and identified through expert recommendation and the Association for Computing Machinery's digital library of conference materials. The search focused on the timeframe June 2014 to September 2019, to offer an update since the time the most recent systematic reviews on this topic concluded their literatures searches. Quality was reviewed using the Mixed Methods Appraisal Tool (MMAT). RESULTS: A total of 38 articles were eligible, and 24 articles rated as high quality were included in a narrative review. Of the included articles, 19 explored DSH risk and 8 explored DSH protection. Most articles reported on cross-sectional quantitative or qualitative studies. Opportunities for both risks and benefits were explored, and potential influences of social media use were considered for subgroups of youth who may be especially vulnerable to suicide. CONCLUSIONS: In the relatively short period of review, the association between social media use and youth DSH was tested in population-based studies, offering preliminary evidence for suicide prevention and treatment efforts. Further research is needed to understand the contribution of social media use to youth DSH, particularly among youth most vulnerable to suicidal risk.

Using 3D printed sinonasal models to visualize and optimize personalized sinonasal sinus irrigation strategies.

BACKGROUND: Topical sinus irrigations (neti-pot, squeeze bottles) play a critical role in the management of sinonasal disease. However, due to intricate nasal anatomy, penetration of topical irrigations to targeted sinus regions may be highly variable, and difficult to objectively predict. Variables, including head positions, injection angles, flow rates, etc. may vary significantly depending on the individual's anatomy. OBJECTIVE: The purpose of this study was to propose a novel idea: using a 3D printed model of sinonasal cavities to visualize and develop a patient-specific irrigation strategy. METHODS: As a proof of concept, 3D replicas of one patient's sinonasal cavities pre- and post-surgery were printed with a Form2 SLA 3D printer based on their CT scans. The setup included rubber/silicon seals attached to the model's nostrils to create a watertight seal with the irrigation device and food color dye added for better visualization of irrigation results. RESULTS: Irrigations were performed on the 3D models with various head positions, injection angles, and flow rates, and were successful to determine the optimal strategy to targeted sinuses. Significant differences were observed between different targeted sinuses and between pre and post-surgery models. CONCLUSION: With more affordable 3D printing, this technology may potentially improve patient care and patient education, allowing clinicians and patients to develop a personalized irrigation strategy and have visual confirmation.

A Particle Tracking Algorithm for Arbitrary Unstructured Grids.

A new semi-analytical algorithm for generating the local groundwater velocity field within irregular three-dimensional grid cells (such as a Voronoi cell) is presented. The method supports particle tracking in the MODFLOW-USG software package for a variety of supported unstructured grid formats. It is shown to replicate the results from the fully analytical Pollock's method when used on a rectilinear grid, and is demonstrated for difficult test cases where there is high spatial variability in the flow field within individual cells. The method is now available as an option in the mod-PATH3DU software package and may be used with most MODFLOW-USG packages without additional intervention.

Reduced growth performance in gilt progeny is not improved by segregation from sow progeny in the grower-finisher phase.

Gilt progeny (GP) are born and weaned lighter than sow progeny (SP) and tend to have higher rates of mortality and morbidity. This study quantified the lifetime growth performance differences between GP and SP and, additionally, evaluated whether segregating GP and SP in the grower-finisher period compared to mixing them within common pens reduced this variation. It was hypothesised that GP would be lighter than SP at every stage and segregation would improve growth performance of both GP and SP. All piglets born to 61 gilts (parity 1) and 47 sows (parities 2 to 7; mean 3.5 ± 0.2) were allocated to four treatments at 10 weeks of age: (i) GP housed together (GG), (ii) GP mixed (M) with SP (GM), (iii) SP housed together (SS) and (iv) SP mixed with GP (SM). The GM and SM pigs were housed together in common pens after movement into the grower-finisher facility. Individual live weight of all progeny was recorded at birth, weaning (WWT), 10 weeks of age (10WT) and sale (SWT). Individual hot carcass weight (HCW), fat depth at the head of the last rib (P2) and dressing percentage were measured at slaughter. Gilt progeny were lighter at birth (P = 0.038), weaning (P < 0.001) and through to sale (P = 0.001) than SP. Nursery and grower-finisher performance differences in GP were highly attributable to their lower WWT compared to SP (P < 0.001 when fitted as a covariate). Segregation of GP and SP increased grower-finisher average daily gain (ADG) in SP but decreased ADG and SWT in GP (P < 0.10). Segregated SP had increased average daily feed intake but only in males (P = 0.007); HCW (P < 0.001) and P2 fat depth (P = 0.055) were higher in mixed female GP, but there was no difference (P > 0.10) in female SP, or in males. In conclusion, GP were lighter at every stage than SP and differences after weaning were highly related to the lighter WWT of GP. Under the conditions of this study, overall segregation of GP and SP showed no consistent advantages in growth performance for both groups and differed significantly between males and females.

Semen parameters are unaffected by statin use in men evaluated for infertility.

The effects of statin use on conventional semen parameters in humans are largely unknown and have not been previously studied in subfertile men. We retrospectively reviewed data from 10,140 patients seen at our fertility clinic between 2002 and 2013 to assess the effects of statin use on semen parameters. Men who used any statins for >3 months before semen sample collection were included as cases. Data were gathered on patient age, medication use and conventional semen parameters. A total of 118 patients (126 samples) used statins for at least 3 months before semen sample collection. Data from 7698 patients (8,760 samples), who were not using any medications, were used as controls. In age-adjusted regression models, statin use was not associated with statistically significant changes in semen parameters. When used in combination with other nonspermatotoxic medications, it was associated with 0.3 ml decrease in semen volume (95% confidence interval: 0.02 to 0.58 ml, p-value = .04). In conclusion, statin use was not adversely associated with semen parameters other than semen volume in subfertile patients. These findings from our large-scale retrospective study suggest that there are no clinically relevant deleterious effects from statin use on conventional semen parameters.

Poorer lifetime growth performance of gilt progeny compared with sow progeny is largely due to weight differences at birth and reduced growth in the preweaning period, and is not improved by progeny segregation after weaning.

Gilt progeny (GP) are born and weaned lighter than sow progeny (SP) and have higher rates of mortality. This study aimed to quantify the performance and survival differences between GP and SP throughout the entire production cycle from birth to sale. Furthermore, the study looked at the effects of segregating GP and SP compared with commingling during rearing within common pens. It was hypothesized that GP would be lighter than SP at every age and have lower rates of survival accompanied by higher rates of medication, and that segregating GP and SP would improve the growth and survival of both groups. All progeny born to 109 gilts (parity 1) and 94 sows (parities 2 to 8) were allocated to 4 postweaning treatments at birth: GP separately penned, GP mixed with SP in a common pen (GM), SP separately penned, and SP mixed with GP in a common pen (SM), with littermates split among treatments. The GM and SM pigs were penned together after weaning. Individual live weight of all progeny was recorded at birth (birth weight [BWT]), weaning (28 d; weaning weight [WWT]), 10 wk of age (10-wk weight [10WT]), and sale (22-23 wk; sale weight [SWT]). Individual HCW, backfat depth, loin depth, and dressing percentage were measured at slaughter. All postweaning mortalities and medications were recorded. The GP had a lighter BWT ( = 0.032), WWT ( < 0.001), 10WT ( < 0.001), and SWT ( < 0.001) than SP as well as a lower HCW ( < 0.001) and dressing percentage ( = 0.012). Postweaning performance differences were mostly attributable to the lighter WWT of GP compared with that of SP when WWT was fitted as a covariate. The GP had a higher mortality in the immediate postweaning period (weaning to 10 wk of age; = 0.028) and from weaning to sale ( = 0.012) than SP, which was also attributable to lower WWT. The GP exhibited a higher incidence of mortality ( = 0.011) due to respiratory tract infection in the grower-finisher period, despite similar medication rates ( = 0.83). Segregation of GP and SP between pens presented no benefit in terms of growth and survival of both groups while requiring added labor and production considerations and, therefore, is not recommended. This study confirms that GP are lighter than SP, on average, at every stage of life from birth to slaughter and that their performance before weaning is an important determinant for whole-of-life performance.