Loss Of Connectivity Research Articles

Fragmentation Level Drives Local Fish Assemblage Diversity Patterns in Fragmented River Basins

Longitudinal connectivity is the main attribute of river ecosystems and is essential for the maintenance of aquatic biota. When longitudinal connectivity decreases in a river network, abundance of some fish species decreases, and local extinctions may occur. Such abundance decreases and extinctions affect local assemblage structure (alpha diversity) and result in a high degree of dissimilarity among local assemblages (higher beta diversity). Specific ecological mechanisms that are behind these biodiversity changes induced by connectivity loss remain poorly understood. Here, we assessed the effects of fragmentation at the local and basin level, as well as local environmental variables on local fish diversity patterns in eight Andean river basins in central Chile (32–39° S). The results indicated that fish assemblages inhabiting pool habitats in highly fragmented basins were characterized by significantly lower species richness and alpha diversity mainly driven by absence of fish species with high dispersion capacities. Our results highlight the importance of the effects of barrier cascades upstream as drivers of local native fish diversity. Sustainable hydropower development necessitates system scale planning of the placement of future barriers and should consider both local and basin scale biodiversity indicators.

Analysis of local head losses in microirrigation lateral connectors based on machine learning approaches

The presence of emitters along the lateral, as well as of connectors along the manifold, causes additional local head losses other than friction losses. An accurate estimation of local losses is of crucial importance for a correct design of microirrigation systems. This paper presents a procedure to assess local head losses caused by 6 lateral start connectors of 32- and 40-mm nominal diameter each under actual hydraulic working conditions based on artificial neural networks (ANN) and gene expression programming (GEP) modelling approaches. Different input–output combinations and data partitions were assessed to analyse the hydraulic performance of the system and the optimum training strategy of the models, respectively. The range of the head losses in the manifold (hsM) is considerable lower than in the lateral (hsL). hsM increases with the protrusion ratio (s/S). hsL does not decrease for a decreasing s/S. There is a correlation between hsL and the Reynolds number in the lateral (ReL). However, this correlation might also be dependent on the flow conditions in the manifold before the derivation. The value of the head loss component due to the protrusion might be influenced by the flow derivation. DN32 connectors and hsM present more accurate estimates. Crucial input parameters are flow velocity and protrusion ratio. The inclusion of friction head loss as input also improves the estimating accuracy of the models. The range of the indicators is considerably worse for DN40 than for DN32. The models trained with all patterns lead to more accurate estimations in connectors 7 to 12 than the models trained exclusively with DN40 patterns. On the other hand, including DN40 patterns in the training process did not involve any improvement for estimating the head losses of DN32 connectors. ANN were more accurate than GEP in DN32. In DN40 ANN were less accurate than GEP for hsM, but they were more accurate than GEP for hsL, while both presented a similar performance for hscombined. Different equations were obtained using GEP to easily estimate the two components of the local loss. The equation that should be used in practice depends on the availability of inputs.

The Significance and Ethics of Digital Livestock Farming

The emergence of precision and digital livestock farming presents an opportunity for sustainable animal farming practices that enhance animal welfare and health. However, this transformation of modern animal farming through digital technology has several implications for the technological, social, economic, and environmental aspects of farming. It is crucial to analyze the ethical considerations associated with the digitalization of modern animal farming, particularly in the context of human–animal relationships and potential objectification. This analysis can help develop frameworks for improving animal welfare and promoting sustainability in animal farming. One of the primary ethical concerns of digital livestock farming is the potential for a digital divide between farmers who have access to advanced technologies and those who do not. This could lead to a disparity in animal welfare and health outcomes for different groups of animals. Additionally, the use of artificial intelligence in digital livestock farming may lead to a loss of personal connection between farmers and animals, which could impact the animal’s well-being. Another ethical concern of digital livestock farming is the potential for the objectification of animals as mere data points. The use of sensors and other monitoring technologies can provide valuable data on animal health and behavior, but it is important to remember that animals are sentient beings with complex emotional and social needs. The use of digital technologies should not lead to neglect of animal welfare or a lack of human responsibility toward animals. Furthermore, social context becomes essential while integrating technologies in livestock farming to overcome ethics. By considering the cultural and societal norms of different communities, we can ensure that the use of digital technologies does not undermine these values. To address these ethical challenges, the development of standards and codes of conduct for the adoption and implementation of digital livestock farming tools and platforms can help ensure that animal welfare and sustainability are prioritized. This can help alleviate the privacy concerns of stakeholders and improve sustainability in animal farming practices. Additionally, the use of virtual and augmented reality technologies can provide a way to enhance human–animal interactions and provide more personalized care to animals, further promoting animal welfare.

Quantification and evolution on degradation mechanisms of proton exchange membrane fuel cell catalyst layer under dynamic testing conditions

The catalyst layer is one of the core components of the Proton Exchange Membrane Fuel Cell (PEMFC). Studying its degradation mechanism is very important to improve the durability of PEMFC. Therefore, the degradation of the catalyst layer after the 100 h, 225 h, and 650 h durability tests are studied quantitatively in this paper. The results show that the agglomeration of Pt particles is the main reason for the degradation of the catalyst layer in the first 100 h, accounting for 80%. Catalyst dissolution and the loss of proton connectivity caused by the ionomer are the main factors for the degradation of the catalyst layer between 225 and 650 h, which increases from 23% in the initial stage to 46%. In addition, the corrosion degree of the carbon support inside the catalyst layer gradually intensified with the test time. This study reveals the dominant degradation mechanism of the catalyst layer in different degradation stages and the evolution of the whole degradation process, which has important guiding significance for the structural design of the catalyst layer for long-life fuel cells.

Outdoor Air Quality Monitoring with Enhanced Lifetime-enhancing Cooperative Data Gathering and Relaying Algorithm (E-LCDGRA) Based Sensor Network

The air continues to be an extremely substantial part of survival on earth. Air pollution poses a critical risk to humans and the environment. Using sensor-based structures, we can get air pollutant data in real-time. However, the sensors rely upon limited-battery sources that are immaterial to be alternated repeatedly amid extensive broadcast costs associated with real-time applications like air quality monitoring. Consequently, air quality sensor-based monitoring structures are lifetime-constrained and prone to the untimely loss of connectivity. Effective energy administration measures must therefore be implemented to handle the outlay of power dissipation. In this study, the authors propose outdoor air quality monitoring using a sensor network with an enhanced lifetime-enhancing cooperative data gathering and relaying algorithm (E-LCDGRA). LCDGRA is a cluster-based cooperative event-driven routing scheme with dedicated relay allocation mechanisms that tackle the problems of event-driven clustered WSNs with immobile gateways. The adapted variant, named E-LCDGRA, enhances the LCDGRA algorithm by incorporating a non-beaconaided CSMA layer-2 un-slotted protocol with a back-off mechanism. The performance of the proposed E-LCDGRA is examined with other classical gathering schemes, including IEESEP and CERP, in terms of average lifetime, energy consumption, and delay

Visual-spatial processing impairment in the occipital-frontal connectivity network at early stages of Alzheimer's disease.

Alzheimer's disease (AD) is the leading cause of dementia worldwide, but its pathophysiological phenomena are not fully elucidated. Many neurophysiological markers have been suggested to identify early cognitive impairments of AD. However, the diagnosis of this disease remains a challenge for specialists. In the present cross-sectional study, our objective was to evaluate the manifestations and mechanisms underlying visual-spatial deficits at the early stages of AD. We combined behavioral, electroencephalography (EEG), and eye movement recordings during the performance of a spatial navigation task (a virtual version of the Morris Water Maze adapted to humans). Participants (69-88 years old) with amnesic mild cognitive impairment-Clinical Dementia Rating scale (aMCI-CDR 0.5) were selected as probable early AD (eAD) by a neurologist specialized in dementia. All patients included in this study were evaluated at the CDR 0.5 stage but progressed to probable AD during clinical follow-up. An equal number of matching healthy controls (HCs) were evaluated while performing the navigation task. Data were collected at the Department of Neurology of the Clinical Hospital of the Universidad de Chile and the Department of Neuroscience of the Faculty of Universidad de Chile. Participants with aMCI preceding AD (eAD) showed impaired spatial learning and their visual exploration differed from the control group. eAD group did not clearly prefer regions of interest that could guide solving the task, while controls did. The eAD group showed decreased visual occipital evoked potentials associated with eye fixations, recorded at occipital electrodes. They also showed an alteration of the spatial spread of activity to parietal and frontal regions at the end of the task. The control group presented marked occipital activity in the beta band (15-20 Hz) at early visual processing time. The eAD group showed a reduction in beta band functional connectivity in the prefrontal cortices reflecting poor planning of navigation strategies. We found that EEG signals combined with visual-spatial navigation analysis, yielded early and specific features that may underlie the basis for understanding the loss of functional connectivity in AD. Still, our results are clinically promising for early diagnosis required to improve quality of life and decrease healthcare costs.

Impacts of existing and planned hydropower dams on river fragmentation in the Balkan Region

The Balkan region has some of the best conserved rivers in Europe, but is also the location of ~3000 planned hydropower dams that are expected to help decarbonise energy production. A conflict between policies that promote renewable hydropower and those that prioritise river conservation has ensued, which can only be resolved with the help of reliable information. Using ground-truthed barrier data, we analysed the extent of current longitudinal river fragmentation in the Balkan region and simulated nine dam construction scenarios that varied depending on the number, location and size of the planned dams. Balkan rivers are currently fragmented by 83,017 barriers and have an average barrier density of 0.33 barriers/km after correcting for barrier underreporting; this is 2.2 times lower than the mean barrier density found across Europe and serves to highlight the relatively unfragmented nature of these rivers. However, our analysis shows that all simulated dam construction scenarios would result in a significant loss of connectivity compared to existing conditions. The largest loss of connectivity (−47 %), measured as reduction in barrier-free length, would occur if all planned dams were built, 20 % of which would impact on protected areas. The smallest loss of connectivity (−8 %) would result if only large dams (>10 MW) were built. In contrast, building only small dams (<10 MW) would cause a 45 % loss of connectivity while only contributing 32 % to future hydropower capacity. Hence, the construction of many small hydropower plants will cause a disproportionately large increase in fragmentation that will not be accompanied by a corresponding increase in hydropower. At present, hydropower development in the Balkan rivers does not require Strategic Environmental Assessment, and does not consider cumulative impacts. We encourage planners and policy makers to explicitly consider trade-offs between gains in hydropower and losses in river connectivity at the river basin scale.

Diabetes Technology and the Human Factor.

Diabetes Technology and the Human Factor.

The impact of brain lesions on health-related quality of life in patients with WHO CNS grade 3 or 4 glioma: a lesion-function and resting-state fMRI analysis

PurposeIn glioma patients, tumor development and multimodality therapy are associated with changes in health-related quality of life (HRQoL). It is largely unknown how different types and locations of tumor- and treatment-related brain lesions, as well as their relationship to white matter tracts and functional brain networks, affect HRQoL.MethodsIn 121 patients with pretreated gliomas of WHO CNS grades 3 or 4, structural MRI, O-(2-[18F]fluoroethyl)-L-tyrosine (FET) PET, resting-state functional MRI (rs-fMRI) and self-reported HRQoL questionnaires (EORTC QLQ-C30/BN20) were obtained. Resection cavities, T1-enhancing lesions, T2/FLAIR hyperintensities, and lesions with pathologically increased FET uptake were delineated. Effects of tumor lateralization, involvement of white matter tracts or resting-state network nodes by different types of lesions and within-network rs-fMRI connectivity were analyzed in terms of their interaction with HRQoL scores.ResultsRight hemisphere gliomas were associated with significantly less favorable outcomes in physical, role, emotional and social functioning, compared with left-sided tumors. Most functional HRQoL scores correlated significantly with right-sided white-matter tracts involvement by T2/FLAIR hyperintensities and with loss of within-network functional connectivity of right-sided nodes. Tumors of the left hemisphere caused significantly more communication deficits.ConclusionIn pretreated high-grade gliomas, right hemisphere lesions are associated with reduced HRQoL scores in most functional domains except communication ability, compared to tumors of the left hemisphere. These relationships are mainly observed for T2/FLAIR lesions involving structural and functional networks in the right hemisphere. The data suggest that sparing the right hemisphere from treatment-related tissue damage may improve HRQoL in glioma patients.

A Hotspot Server and Two Line ISP Load Balance and Failover Using the Mikrotik RB951UI 2HND with PCC Method

When one connection fails, failover makes sure the connection is always available, and the hotspot server can make it simpler for customers to access the internet with a username and password. The loss of an internet connection, a slow connection, and output that is insufficient for your bandwidth are some common issues with the internet network. Managing hotspot servers is less of a worry for many schools and colleges, as they often just use one ISP (internet service provider) connection. The drawback of employing a single line ISP is that blended learning-based lectures will currently cease to exist if the ISP goes down. Therefore, the Mikrotik RB951Ui can do load balancing, failover, and hotspot server management. When using the Per Connection Classifier (PCC) method, which in this study was successful in overcoming the aforementioned issues, the internet connection became stable because the load was split between the two ISPs, and when the internet at one of the ISPs went down, there were still other connections that backed up. Additionally, there is a wifi hotspot management system that uses a username, password, and bandwidth restrictions for each user.

Integration of e-learning approaches in a post-pandemic learning environment – Norwegian nursing students’ recommendations from an action research study

The covid-19 pandemic has profoundly led to changes in use of digital platforms, online teaching, and e-learning strategies. The aim of the present study was to examine how future pedagogical approaches can promote constructive learning environments and facilitate nursing students learning processes in future post-pandemic scenarios based on an action research study, which were conducted through several steps from January 2021 through January 2022 in a Bachelor of Nursing program at UiT the Arctic University of Norway. Students from the 2020 enrollment were invited to focus group interviews in March 2021. The interviews were transcribed, and content analyzed, resulting in concrete advice, which were implemented for the next enrollment. Students from the 2021 enrollment were invited to similar focus groups, resulting in refined advice, which will be presented. The pandemic situation resulted in extensive use of digital platforms for the 2020 enrollment. Students from this cohort described shock and disappointment connected to their study start. They expected a new life, meeting new friends and to develop a student identity, but their expectations were broken. The loss of social connections led to isolation and a weak link to the program and to the nursing profession. They recommended integrated training of theoretical and practical skills in small groups combined with short, well-prepared digital lectures equivalent to “flipped classroom” approaches. Implementing their advice, the 2021 enrollment's experience became different. This group was prepared for extensive use of digital platforms and gave future advise on increased flexibility and balance between the various learning activities centered around the clinical sessions. Based on these experiences during the pandemic, we suggest that digital platforms and e-learning strategies facilitate nursing students learning in combination with active and social learning environments.

범죄경력자 및 가족의 낙인인식에 영향을 미치는 심리요인

The reintegration of individuals with a criminal history into society after serving time in correctional facilities poses significant challenges for both the individual and their family. Approximately 60,000 such individuals are released back into society each year, and the impact of imprisonment and release can be deeply detrimental to the well-being of their families. The stigma faced by families of these individuals often leads to isolation and the loss of social connections, as well as exacerbating the practical difficulties they may experience. This stigma can also lead to negative experiences and increased suffering for the family, beyond that experienced by the individual with a criminal history. Given that the support and resources provided by the family can greatly contribute to the individual's successful reintegration and reduced likelihood of recidivism, it is important to protect families from social stigma and discrimination. However, research on the stigma faced by these families is limited, as are legal and support systems specifically geared towards them. This study aims to better understand the stigma faced by families of individuals with a criminal history, as well as the psychological factors that influence their perception of this stigma.&#x0D; This study used descriptive statistics, reliability analysis, t-test, and regression analysis on a total of 127 data points collected from the 2022 Gyeonggi-do 『Psychological treatment support project for families of individuals on probation and others』. The data included 57 responses from individuals with criminal records and 70 responses from their family members.&#x0D; As a result, there were statistically significant differences in the stigma perception of individuals with a criminal record and their families in terms of negative anger response, family predictability, drinking frequency, and drinking problems. However, no significant differences were found between the two groups in terms of the rest of the variables, including the perception of stigma, indicating that the psychological state of the family is not significantly different from that of the individuals with a criminal history. The main psychological factors influencing the stigma of individuals with a criminal record and their families were found to be negative anger responses and negative self-concept. In addition, family predictability was identified as a psychological factor affecting self-stigma among families, suggesting that a greater degree of predictability among family members may be associated with higher levels of self-stigma and an increased number of negative predictions.&#x0D; This study suggests the need for further research on the psychological state of families of individuals with a criminal history, as well as the implementation of ongoing educational and psychological support programs to address the challenges faced by these families. Additionally, it is important to consider expanding the legal system to provide practical support for these families.

Teacher Perceptions of Self-Efficacy in Teaching Online During the COVID-19 Pandemic

To examine the effects of the sudden shift to online instruction due to the COVID-19 pandemic in the early months of 2020, we sought to get a firsthand understanding of the experiences of teachers who were required to make the change to full online teaching. Teaching online requires technological knowledge, but it also requires a different pedagogy in order to keep students engaged and motivated to learn. Many educators indicated that this was a significant challenge. Our goal was to illuminate teachers’ experiences in order to include their voices in changes to educator preparation programs. A total of 699 complete survey responses were received representing educators in several grade levels working in nine states in the United States. Qualitative analysis revealed that many responses were related to extant research on teachers’ self-efficacy. Thus, this paper will shed light on the experiences of educators during the first semester of 2020 including the months of January through April, and teachers’ perceived efficacy. We find that teachers felt more efficacious regarding aspects of online teaching over which they felt an internal locus of control, such as delivery of curriculum and their own skill in the use of technology. For items over which they had less control, such as parental support and involvement, student motivation, and student access to adequate technology, teachers indicated much less efficacy. The majority of responses paint a complicated and somewhat dismal picture of the loss of personal connection with their students. Based on these data, recommendations for both education preparation programs, and policy are discussed such as districts and schools must provide sufficient professional learning opportunities and create a culture of collaboration amongst teachers that can assist them in building internal school capacity for good online instruction for their students. The COVID-19 pandemic should be used as an opportunity to evaluate gaps in digital equity and make positive strides to ensure all students, regardless of race, disability, economic background, or geographic location, have full access to quality online education. Keywords: teacher preparation, educator preparation, online teaching, COVID-19, self-efficacy

Long-term performance assessment of post-tensioned timber connections under different climates

Timber structures are sensitive to the changes in climatic condition as wood absorbs or desorbs moisture from the ambient environment. The varying climatic condition can induce time-dependent deformation of timber that further leads to long-term variation of structural performance. Such issue needs to be carefully considered during the design process especially for structures in outdoor environment and uncontrolled indoor environment. This study assesses the long-term prestressing force loss of post-tensioned timber connections under different climatic conditions. First, the climatic conditions in ten Chinese and Canadian cities were identified. The statistics and yearly variations of relative humidity and temperature were analyzed and compared. Subsequently, a validated numerical model was used to predict the long-term variation of moisture content over 50 years in the ten cities. The effects of initial moisture content and member sizes were discussed. Finally, four long-term performance (prestressing force loss) levels were proposed based on the maximum lifetime prestressing force loss percentage. Various post-tensioned timber connections accounting for different climatic conditions, initial moisture content, member sizes and connection details were simulated and assessed by determining the long-term performance level. The results in this study demonstrated that climatic condition significantly affected the long-term performance level of post-tensioned timber connections. Furthermore, the percentage of extensive prestressing force loss during the long-term service was closely correlated with the initial moisture content, member sizes and connection details.

Genetic diversity and connectivity of moose (Alces americanus americanus) in eastern North America

Genetic diversity is critical to a population’s ability to overcome gradual environment change. Large-bodied wildlife existing in regions with relatively high human population density are vulnerable to isolation-induced genetic drift, population bottlenecks, and loss of genetic diversity. Moose (Alces americanus americanus) in eastern North America have a complex history of drastic population changes. Current and potential threats to moose populations in this region could be exacerbated by loss of genetic diversity and connectivity among subpopulations. Existing genetic diversity, gene flow, and population clustering and fragmentation of eastern North American moose are not well quantified, while physical and anthropogenic barriers to population connectivity already exist. Here, single nucleotide polymorphism (SNP) genotyping of 507 moose spanning five northeastern U.S. states and one southeastern Canadian province indicated low diversity, with a high proportion of the genomes sharing identity-by-state, with no consistent evidence of non-random mating. Gene flow estimates indicated bidirectionality between all pairs of sampled areas, with magnitudes reflecting clustering and differentiation patterns. A Discriminant Analysis of Principal Components analysis indicated that these genotypic data were best described with four clusters and indicated connectivity across the Saint Lawrence River and Seaway, a potential physical barrier to gene flow. Tests for genetic differentiation indicated restricted gene flow between populations across the Saint Lawrence River and Seaway, and between many sampled areas facing expanding human activity. These results document current genetic variation and connectivity of moose populations in eastern North America, highlight potential challenges to current population connectivity, and identify areas for future research and conservation.

Pause But Not Panic: Exploring COVID-19 as a Critical Incident for Nonprofit Workers

Critical incidents often have significant impacts on workers, sometimes causing disruptions to career pathways and a re-evaluation of past career decisions. This article seeks to explore the impact of the COVID-19 pandemic on nonprofit workers and their commitment to the sector using a critical incidents lens. In-depth interviews with nonprofit workers provided insights on the pandemic’s impact on workers’ personal and professional lives and how they made sense of these. Changes to work including flexibility and work-from-home options were often viewed positively, yet workers expressed a loss of connection with their colleagues, mental health and well-being challenges, as well as challenges to adapt to new ways of working. In making sense of these changes, commitment to the sector was mostly sustained; however, respondents also noted a shift in priorities and expressed a desire for better balance between their personal and professional lives.

Dopaminergic connectivity reconfiguration in the dementia with Lewy bodies continuum

IntroductionThe impairment of nigrostriatal dopaminergic network is a core feature of dementia with Lewy bodies (DLB). The involvement and reconfiguration of extranigrostriatal dopaminergic circuitries in the DLB continuum is still theme of debate. We aim to investigate in vivo the dynamic changes of local and long-distance dopaminergic networks across DLB continuum. MethodsForty-nine patients (including 29 with dementia and 20 prodromal cases) and fifty-two controls entered the study. Each subject underwent a standardized clinical and neurological examination and performed Brain SPECT to measuring brain dopamine transporter (DAT) density. Spatially normalized images underwent the occipital-adjusted specific binding to obtain parametric data. The ANCOVA was applied to assess 123I-FP-CIT differences between pDLB, overt-DLB and CG, considering age, gender, and motor impairment as variables of no interest. Between-nodes correlation analysis measured molecular connectivity within the ventral and dorsal dopaminergic networks. ResultsProdromal DLB and DLB patients showed comparable nigrostriatal deficits in basal ganglia regions compared with CG. Molecular connectivity analyses revealed extensive connectivity losses, more in ventral than in dorsal dopaminergic network in DLB dementia. Conversely, the prodromal group showed increased connectivity compared to CG, mostly putamen-thalamus-cortical and striatal-cortical connectivity. ConclusionsThis study indicates a comparable basal ganglia deficit in nigrostriatal projections in DLB continuum and supports a different reorganization of extra-striatal dopaminergic connectivity in the prodromal phases of DLB. The shift from an increased to a decreased bilateral putamen-thalamus-cortex connectivity might be a hallmark of transition from prodromal to dementia DLB stages.

Legacies of the Past and the American Family: Sam Shepard’s True West and Suzan-Lori Parks’s Topdog /Underdog

Isolation from societal and historical continuity ingrained in American thought and culture has resulted in an unprecedented economic growth, creativity, and flexibility in all facets of American life. Paradoxically, a constant search for an American past—generated by the lack of a common history—also prevails in American culture and these mutually exclusive trends lead to a sense of “rootlessness, loss of connections, and anxiety about identity” (Menides 607). American literary expressiveness appears to reflect these opposing views on history as well as the impact these attitudes exert on the (in)stability of the American character. Viewed from the “classic” period of American literature a variety of responses were generated by the literary culture. American writers’ approaches to history range from evident separation from the constraints and restraints of history and tradition (Emerson, Thoreau) through creating romanticized versions of the American past (Cooper, Longfellow) to the search of a “usable past”2 (Eliot, Pound) that would explain the causes and impinge on the way how Americans exist in the present (Menides 607).

Mine tailings storage dams modify upstream headwater fish assemblages

Riverscape connectivity is a critically important component determining the ecological condition of lotic ecosystems. We evaluated changes in fish assemblages caused by the loss of connectivity by mine tailings storage dams (TSDs), hypothesizing that headwater fish assemblages are restructured by TSDs located downstream, even though the upstream habitats are not altered. We used standard methods to collect fish in 24 first to third order sites, with half draining to TSDs (dammed) and the other half free from this impact (undammed). To identify differences between treatments, we used PERMANOVA to test both environmental variables and ichthyofauna composition (Bray-Curtis similarity index) and evaluated the biological metrics that most influenced assemblage composition change. As expected, we observed no difference between treatments for environmental variables, but we did observe differences in fish assemblage composition. We also observed five metrics with lower values in dammed streams (richness and abundance of intolerant species, siluriform richness, and abundance of Pareiorhaphis cf. proskynita and Trichomycterus brasiliensis) and two metrics with higher values in dammed streams (perciform richness and abundance of Oligosarcus argenteus). We believe these changes resulted from of stream fragmentation by TSDs, in addition to source-sink mechanisms and conclude that mine TSDs located downstream change headwater fish assemblages, an impact often neglected in biomonitoring and bioassessment studies.

Reversine ameliorates hallmarks of cellular senescence in human skeletal myoblasts via reactivation of autophagy.

Cellular senescence leads to the depletion of myogenic progenitors and decreased regenerative capacity. We show that the small molecule 2,6-disubstituted purine, reversine, can improve some well-known hallmarks of cellular aging in senescent myoblast cells. Reversine reactivated autophagy and insulin signaling pathway via upregulation of Adenosine Monophosphate-activated protein kinase (AMPK) and Akt2, restoring insulin sensitivity and glucose uptake in senescent cells. Reversine also restored the loss of connectivity of glycolysis to the TCA cycle, thus restoring dysfunctional mitochondria and the impaired myogenic differentiation potential of senescent myoblasts. Altogether, our data suggest that cellular senescence can be reversed by treatment with a single small molecule without employing genetic reprogramming technologies.