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Now showing items 21-40 of 17578

    • Newly identified sex chromosomes in the Sphagnum (peat moss) genome alter carbon sequestration and ecosystem dynamics

      Healey, A.L.; Piatkowski, B.; Lovell, J.T.; Sreedasyam, A.; Carey, S.B.; Mamidi, S.; Shu, S.; Plott, C.; Jenkins, J.; Lawrence, T.; et al. (Nature Research, 2023-02-06)
      Peatlands are crucial sinks for atmospheric carbon but are critically threatened due to warming climates. Sphagnum (peat moss) species are keystone members of peatland communities where they actively engineer hyperacidic conditions, which improves their competitive advantage and accelerates ecosystem-level carbon sequestration. To dissect the molecular and physiological sources of this unique biology, we generated chromosome-scale genomes of two Sphagnum species: S. divinum and S. angustifolium. Sphagnum genomes show no gene colinearity with any other reference genome to date, demonstrating that Sphagnum represents an unsampled lineage of land plant evolution. The genomes also revealed an average recombination rate an order of magnitude higher than vascular land plants and short putative U/V sex chromosomes. These newly described sex chromosomes interact with autosomal loci that significantly impact growth across diverse pH conditions. This discovery demonstrates that the ability of Sphagnum to sequester carbon in acidic peat bogs is mediated by interactions between sex, autosomes and environment. © 2023, The Author(s).
    • Extending quantum key distribution through proxy re-encryption

      Lemons, N.; Gelfand, B.; Lawrence, N.; Thresher, A.; Tripp, J.L.; Gammel, W.P.; Nadiga, A.; Meier, K.; Newell, R.; Program in Applied Mathematics, The University of Arizona (Institute of Electrical and Electronics Engineers Inc., 2023-06-29)
      Modern quantum key distribution (QKD) network designs are based on sending photons from one node to another and require free-space or dedicated fiber optic cables between nodes. The purpose of this is to co-generate secret key material on both sides of the quantum channel. In addition to this quantum link, there are several insecure classical channels that allow QKD algorithms to exchange book-keeping information and send symmetrically encrypted data. The attenuation of photons transmitted through fiber becomes too high to practically generate key material over fiber at distances of more than 100 km. Free-space transmission through the atmosphere or the vacuum of space can reduce attenuation, but at the cost of system complexity and sensitivity to other impairments, such as weather. To extend the effective range of QKD networks, we present a method that combines QKD algorithms with post-quantum, homomorphic key-switching to allow multiple parties to effectively share secret key material over longer distances through semi-trusted relay nodes. We define how such a system should work for arbitrary network topologies and provide proofs that our scheme is both correct and secure. We assess the feasibility of this solution by building and evaluating two implementations based on lattice-based cryptography: learning with errors. © 2009-2012 Optica Publishing Group.
    • A Framework to Assess Remote Sensing Algorithms for Satellite-Based Flood Index Insurance

      Thomas, M.; Tellman, E.; Osgood, D.E.; Devries, B.; Islam, A.S.; Steckler, M.S.; Goodman, M.; Billah, M.; Department of Geography, Development and Environment, University of Arizona (Institute of Electrical and Electronics Engineers Inc., 2023-02-10)
      Remotely sensed data have the potential to monitor natural hazards and their consequences on socioeconomic systems. However, in much of the world, inadequate validation data of disaster damage make reliable use of satellite data difficult. We attempt to strengthen the use of satellite data for one application-flood index insurance-which has the potential to manage the largely uninsured losses from floods. Flood index insurance is a particularly challenging application of remote sensing due to floods' speed, unpredictability, and the significant data validation required. We propose a set of criteria for assessing remote sensing flood index insurance algorithm performance and provide a framework for remote sensing application validation in data-poor environments. Within these criteria, we assess several validation metrics-spatial accuracy compared to high-resolution PlanetScope imagery (F1), temporal consistency as compared to river water levels (Spearman's ρ), and correlation to government damage data (R2)-that measure index performance. With these criteria, we develop a Sentinel-1 flood inundation time series in Bangladesh at high spatial (10 m) and temporal (∼weekly) resolution and compare it to a previous Sentinel-1 algorithm and a Moderate Resolution Imaging Spectroradiometer (MODIS) time series used in flood index insurance. Results show that the adapted Sentinel-1 algorithm (F1avg = 0.925, ρavg = 0.752, R2 = 0.43) significantly outperforms previous Sentinel-1 and MODIS algorithms on the validation criteria. Beyond Bangladesh, our proposed validation criteria can be used to develop and validate better remote sensing products for index insurance and other flood applications in places with inadequate ground truth damage data. © 2008-2012 IEEE.
    • The prediction of uneven snowpack response to forest thinning informs forest restoration in the central Sierra Nevada

      Lewis, G.; Harpold, A.; Krogh, S.A.; Broxton, P.; Manley, P.N.; School of Natural Resources and the Environment, University of Arizona (John Wiley and Sons Ltd, 2023-08-29)
      The Sierra Nevada has experienced unprecedented wildfires and reduced snowmelt runoff in recent decades, due partially to anthropogenic climate change and over a century of fire suppression. To address these challenges, public land agencies are planning forest restoration treatments, which have the potential to both increase water availability and reduce the likelihood of uncontrollable wildfires. However, the impact of forest restoration on snowpack is site specific and not well understood across gradients of climate and topography. To improve our understanding of how forest restoration might impact snowpack across diverse conditions in the central Sierra Nevada, we run the high-resolution (1 m) energy and mass balance Snow Physics and Lidar Mapping (SnowPALM) model across five 23–75 km2 subdomains in the region where forest thinning is planned or recently completed. We conduct two virtual thinning experiments by removing all trees shorter than 10 or 20 m tall and rerunning SnowPALM to calculate the change in meltwater input. Our results indicate heterogeneous responses to thinning due to differences in climate and wind across our five central Sierra Nevada subdomains. We also predict the largest increases in snow retention when thinning forests with tall (7–20 m) and dense (40–70% canopy cover) trees, highlighting the importance of pre-thinning vegetation structure. We develop a decision support tool using a random forests model to determine which regions would most benefit from thinning. In many locations, we expect major forest restoration to increase snow accumulation, while other areas with short and sparse canopies, as well as sunny and windy climates, are more likely to see decreased snowpack following thinning. Our decision support tool provides stand-scale (30 m) information to land managers across the central Sierra Nevada region to best take advantage of climate and existing forest structure to obtain the greatest snowpack benefits from forest restoration. © 2023 The Authors. Ecohydrology published by John Wiley & Sons Ltd.
    • The gauge coupled two-body problem in a ring

      Priestley, J.; Valentí-Rojas, G.; Wright, E.M.; Öhberg, P.; Wyant College of Optical Sciences, University of Arizona (Institute of Physics, 2023-01-23)
      We study the properties of two quantum particles which are confined in a ring. The particles interact via a long-range gauge potential proportional to the distance between the particles. It is found that the two-body ground state corresponds to a state with non-zero angular momentum provided that the interaction between the particles is strong enough. In addition, the particles are correlated in the sense that depending on the interaction strength there is a propensity to be found close together or separated in the ring. We discuss the effect of measuring the position of one of the particles and thereby removing the particle from the ring, where we show that the remaining particle can be prepared in a non-dispersive state with non-zero angular momentum. © 2023 The Author(s). Published by IOP Publishing Ltd.
    • Utility of the social vulnerability index to risk stratify atrial fibrillation mortality outcomes

      Ibrahim, R.; Ravi, S.; Habib, A.; Lee, J.Z.; Department of Medicine, University of Arizona (John Wiley and Sons Inc, 2023-05-24)
      Background: Multiple methods of quantifying social determinants of health exist, such as the social vulnerability index (SVI). We assess the impact of the SVI on atrial fibrillation (AF)-related cardiovascular disease mortality. Methods: CDC databases were used to obtain mortality and SVI information. Age-adjusted mortality rates (AAMR) were compared among all US counties, aggregated by SVI quartiles. Results: AAMR was not increased in counties within the highest SVI quartile, consistent across gender and geographic subgroups. Conclusions: Increased SVI is a poor marker to predict mortality outcomes associated with AF. © 2023 The Authors. Journal of Arrhythmia published by John Wiley & Sons Australia, Ltd on behalf of Japanese Heart Rhythm Society.
    • Sensitive near-infrared circularly polarized light detection via non-fullerene acceptor blends

      Wan, L.; Zhang, R.; Cho, E.; Li, H.; Coropceanu, V.; Brédas, J.-L.; Gao, F.; Department of Chemistry and Biochemistry, University of Arizona (Nature Research, 2023-06-08)
      Circularly polarized light (CPL) is widely used for various applications in sensing and imaging1–3. An ongoing challenge is to realize high-quality CPL detection using chiral organic semiconductors, especially in the near-infrared (NIR) region4. Chiral molecules tend to rely on twisted stereogenic moieties; however, conventional approaches to reduce the bandgap of organic semiconductors are based on the use of co-planar backbones that commonly lead to molecular symmetries preventing chirality. Here we report a widely applicable strategy to directly induce chiroptical activity in planar non-fullerene acceptors5–7, which are widely used for high-performance organic photovoltaics and provide a wealth of opportunities to fill the spectral gap of CPL detection in the NIR regime. We demonstrate proof-of-concept circularly polarized organic photodiodes using chiroptically active non-fullerene acceptor blends, which exhibit strong circular dichroism and hence great sensitivity to CPL in the NIR region. Importantly, this strategy is found to be effective in a wide series of state-of-the-art non-fullerene acceptor families including ITIC5, o-IDTBR6 and Y6 analogues7, which substantially broadens the range of materials applicable to NIR CPL detection. © 2023, The Author(s).
    • In Situ Thermolysis of a Ni Salt on Amorphous Carbon and Graphene Oxide Substrates

      Tamadoni, Saray, M.; Yurkiv, V.; Shahbazian-Yassar, R.; Department of Aerospace and Mechanical Engineering, University of Arizona (John Wiley and Sons Inc, 2023-04-23)
      Understanding the thermal decomposition of metal salt precursors on carbon structures is essential for the controlled synthesis of metal-decorated carbon nanomaterials. Here, the thermolysis of a Ni precursor salt, NiCl2·6H2O, on amorphous carbon (a-C) and graphene oxide (GO) substrates is explored using in situ transmission electron microscopy. Thermal decomposition of NiCl2·6H2O on GO occurs at higher temperatures and slower kinetics than on a-C substrate. This is correlated to a higher activation barrier for Cl2 removal calculated by the density functional theory, strong Ni-GO interaction, high-density oxygen functional groups, defects, and weak van der Waals using GO substrate. The thermolysis of NiCl2·6H2O proceeds via multistep decomposition stages into the formation of Ni nanoparticles with significant differences in their size and distribution depending on the substrate. Using GO substrates leads to nanoparticles with 500% smaller average sizes and higher thermal stability than a-C substrate. Ni nanoparticles showcase the fcc crystal structure, and no size effect on the stability of the crystal structure is observed. These findings demonstrate the significant role of carbon substrate on nanoparticle formation and growth during the thermolysis of carbon–metal heterostructures. This opens new venues to engineer stable, supported catalysts and new carbon-based sensors and filtering devices. © 2023 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH.
    • Correlating the Hybridization of Local-Exciton and Charge-Transfer States with Charge Generation in Organic Solar Cells

      Qian, D.; Pratik, S.M.; Liu, Q.; Dong, Y.; Zhang, R.; Yu, J.; Gasparini, N.; Wu, J.; Zhang, T.; Coropceanu, V.; et al. (John Wiley and Sons Inc, 2023-07-21)
      In organic solar cells with very small energetic-offset (ΔELE − CT), the charge-transfer (CT) and local-exciton (LE) states strongly interact via electronic hybridization and thermal population effects, suppressing the non-radiative recombination. Here, we investigated the impact of these effects on charge generation and recombination. In the blends of PTO2:C8IC and PTO2:Y6 with very small, ultra-fast CT state formation was observed, and assigned to direct photoexcitation resulting from strong hybridization of the LE and CT states (i.e., LE-CT intermixed states). These states in turn accelerate the recombination of both CT and charge separated (CS) states. Moreover, they can be significantly weakened by an external-electric field, which enhanced the yield of CT and CS states but attenuated the emission of the device. This study highlights that excessive LE-CT hybridization due to very low, whilst enabling direct and ultrafast charge transfer and increasing the proportion of radiative versus non-radiative recombination rates, comes at the expense of accelerating recombination losses competing with exciton-to-charge conversion process, resulting in a loss of photocurrent generation. © 2023 The Authors. Advanced Energy Materials published by Wiley-VCH GmbH.
    • Detrital zircon U-Pb and Hf isotope signature of Carboniferous and older strata of the Yukon-Tanana terrane in Yukon, Canadian Cordillera: Implications for terrane correlations and the onset of Late Devonian arc magmatism

      Kroeger, E.D.L.; McClelland, W.C.; Colpron, M.; Piercey, S.J.; Gehrels, G.E.; Department of Geosciences, University of Arizona (Geological Society of America, 2023-05-19)
      The Yukon-Tanana terrane in Yukon, Canada, records Late Devonian (ca. 366–360 Ma) rifting and the onset of latest Devonian–Carboniferous arc and back-arc magmatism (ca. 360–325 Ma) in the Northern Cordillera. Detrital zircon U-Pb and Hf isotope analyses indicate that the metasedimentary basement of the Yukon-Tanana terrane was sourced in northwestern Laurentia. Sandstones in Late Devonian–Carboniferous successions generally have robust Late Devonian–Mississippian age peaks, and their Hf isotope signatures are characterized by strongly negative εHft values in Late Devonian zircons followed by progressively more juvenile εHft values in Carboniferous zircons. This Hf isotopic “pull-up” reflects the melting of Precambrian crust related to regional extension in the Late Devonian, followed by progressively more juvenile magmatism as the arc matured through the Carboniferous. Paleozoic rocks of the Tracy Arm terrane in southeastern Alaska, USA (formerly Yukon-Tanana south), have been compared with the Yukon-Tanana terrane in Yukon. Detrital zircons from the metasedimentary basement to the Tracy Arm terrane have distinct Precambrian populations that indicate sources along a different segment of the Laurentian margin compared to basement of the Yukon-Tanana terrane. Magmatism in the Tracy Arm terrane ranges from 440 Ma to 360 Ma and is characterized by an Hf isotopic “pull-down” in the Silurian to Early Devonian, followed by a “pull-up” in the Middle to Late Devonian and a second “pull-down” in the Late Devonian to early Mississippian. Thus, the Yukon-Tanana and Tracy Arm terranes record distinct pre-Carboniferous histories. Interactions between these two terranes are suggested by the influx of exotic early Mississippian clasts and detrital zircons on the Tracy Arm terrane that match sources in the Yukon-Tanana terrane. © 2023 The Authors
    • Identifying sources of non-unique detrital age distributions through integrated provenance analysis: An example from the Paleozoic Central Colorado Trough

      Smith, T.M.; Saylor, J.E.; Lapen, T.J.; Hatfield, K.; Sundell, K.E.; Department of Geosciences, University of Arizona (Geological Society of America, 2023-01-18)
      To address the longstanding issue of provenance interpretation of non-unique detrital zircon age populations, we integrated zircon U-Pb, rare earth element (REE), and εHf(t) data from upper Paleozoic strata in the northern Central Colorado Trough and Cambrian intrusions with petrography, paleocurrent data, and structural and stratigraphic observations. This data set indicates that Cambrian sediment was shed by multiple local sources instead of distant sources hundreds of kilometers away, and it reveals a detailed history of tectonic drainage reorganization in the northern Central Colorado Trough during Ancestral Rocky Mountain deformation. During the Early–Middle Pennsylvanian, Cambrian detrital zircons were a minor constituent of northern Central Colorado Trough sediment. However, during the Late Pennsylvanian–early Permian, westward advancement of the adjacent Apishapa Uplift deformation front precipitated drainage reorganization, which resulted in an episode of dominant Cambrian detrital zircon sourcing. Paleocurrent and petrographic data indicate that the source of Cambrian detritus was shed by an igneous rock body that was ≤15 km northeast of the depocenter, which has since been eroded away or mantled by Tertiary volcanic rocks. The addition of zircon petrochronology to the data set applied here was critical in confirming this hidden source of detritus and elucidating the compositional characteristics of that igneous rock. Zircon εHf(t) provided a regional provenance indicator of a western Laurentian affinity, and REE composition aided in discriminating possible local sources of Cambrian zircon. Furthermore, this work serves as a case study of a dominant Cambrian detrital zircon signature sourced from outside of the well-known Amarillo-Wichita Uplift, and it has implications for the interpretation of such detrital spectra in the context of a direct-from- basement source or the recycling of Cambrian zircon-dominated rocks. In summary, we demonstrate the utility of this multi-provenance proxy approach in interpreting a complex structural history of a dynamic hinterland and concomitant drainage reorganization through an in-depth investigation into the basin record © 2023,Geosphere. All Rights Reserved.
    • Association of type 2 diabetes mellitus with dementia-related and non–dementia-related mortality among postmenopausal women: A secondary competing risks analysis of the women's health initiative

      Titcomb, T.J.; Richey, P.; Casanova, R.; Phillips, L.S.; Liu, S.; Karanth, S.D.; Saquib, N.; Nuño, T.; Manson, J.E.; Shadyab, A.H.; et al. (John Wiley and Sons Inc, 2023-08-10)
      INTRODUCTION: Alzheimer's disease (AD) and AD-related dementias (ADRD) are leading causes of death among older adults in the United States. Efforts to understand risk factors for prevention are needed. METHODS: Participants (n = 146,166) enrolled in the Women's Health Initiative without AD at baseline were included. Diabetes status was ascertained from self-reported questionnaires and deaths attributed to AD/ADRD from hospital, autopsy, and death records. Competing risk regression models were used to estimate the cause-specific hazard ratios (HRs) and 95% confidence intervals (CIs) for the prospective association of type 2 diabetes mellitus (T2DM) with AD/ADRD and non-AD/ADRD mortality. RESULTS: There were 29,393 treated T2DM cases and 8628 AD/ADRD deaths during 21.6 (14.0–23.5) median (IQR) years of follow-up. Fully adjusted HRs (95% CIs) of the association with T2DM were 2.94 (2.76–3.12) for AD/ADRD and 2.65 (2.60–2.71) for the competing risk of non-AD/ADRD mortality. DISCUSSION: T2DM is associated with AD/ADRD and non-AD/ADRD mortality. Highlights: Type 2 diabetes mellitus is more strongly associated with Alzheimer's disease (AD)/AD and related dementias (ADRD) mortality compared to the competing risk of non-AD/ADRD mortality among postmenopausal women. This relationship was consistent for AD and ADRD, respectively. This association is strongest among participants without obesity or hypertension and with younger age at baseline, higher diet quality, higher physical activity, higher alcohol consumption, and older age at the time of diagnosis of type 2 diabetes mellitus. © 2023 The Authors. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.
    • Radix+: High-throughput georeferencing and data ingestion over voluminous and fast-evolving phenotyping sensor data

      Mitra, S.; Roselius, M.; Andrade-Sanchez, P.; McKay, J.K.; Pallickara, S.L.; Department of Biosystems Engineering, University of Arizona (John Wiley and Sons Ltd, 2023-02-16)
      Remote sensing of plant traits and their environment facilitates non-invasive, high-throughput monitoring of the plant's physiological characteristics. However, voluminous observational data generated by such autonomous sensor networks overwhelms scientific users when they have to analyze the data. In order to provide a scalable and effective analysis environment, there is a need for storage and analytics that support high-throughput data ingestion while preserving spatiotemporal and sensor-specific characteristics. Also, the framework should enable modelers and scientists to run their analytics while coping with the fast and continuously evolving nature of the dataset. In this paper, we present Radix+, a high-throughput distributed data storage system for supporting scalable georeferencing, and interactive query-based spatiotemporal analytics with trackable data integrity. We include empirical evaluations performed on a commodity machine cluster with up to 1 TB of data. Our benchmarks demonstrate subsecond latency for majority of our evaluated queries and (Formula presented.) improvement in data ingestion rate over systems such as Geomesa. © 2023 The Authors. Concurrency and Computation: Practice and Experience published by John Wiley & Sons Ltd.
    • A research agenda for the science of actionable knowledge: Drawing from a review of the most misguided to the most enlightened claims in the science-policy interface literature

      Jagannathan, K.; Emmanuel, G.; Arnott, J.; Mach, K.J.; Bamzai-Dodson, A.; Goodrich, K.; Meyer, R.; Neff, M.; Sjostrom, K.D.; Timm, K.M.F.; et al. (Elsevier Ltd, 2023-06)
      Linking science with action affords a prime opportunity to leverage greater societal impact from research and increase the use of evidence in decision-making. Success in these areas depends critically upon processes of producing and mobilizing knowledge, as well as supporting and making decisions. For decades, scholars have idealized and described these social processes in different ways, resulting in numerous assumptions that now variously guide engagements at the interface of science and society. We systematically catalog these assumptions based on prior research on the science-policy interface, and further distill them into a set of 26 claims. We then elicit expert perspectives (n = 16) about these claims to assess the extent to which they are accurate or merit further examination. Out of this process, we construct a research agenda to motivate future scientific research on actionable knowledge, prioritizing areas that experts identified as critical gaps in understanding of the science-society interface. The resulting agenda focuses on how to define success, support intermediaries, build trust, and evaluate the importance of consensus and its alternatives – all in the diverse contexts of science-society-decision-making interactions. We further raise questions about the centrality of knowledge in these interactions, discussing how a governance lens might be generative of efforts to support more equitable processes and outcomes. We offer these suggestions with hopes of furthering the science of actionable knowledge as a transdisciplinary area of inquiry. © 2023 The Authors
    • The ecological causes of functional distinctiveness in communities

      Munoz, F.; Klausmeier, C.A.; Gaüzère, P.; Kandlikar, G.; Litchman, E.; Mouquet, N.; Ostling, A.; Thuiller, W.; Algar, A.C.; Auber, A.; et al. (John Wiley and Sons Inc, 2023-06-15)
      Recent work has shown that evaluating functional trait distinctiveness, the average trait distance of a species to other species in a community offers promising insights into biodiversity dynamics and ecosystem functioning. However, the ecological mechanisms underlying the emergence and persistence of functionally distinct species are poorly understood. Here, we address the issue by considering a heterogeneous fitness landscape whereby functional dimensions encompass peaks representing trait combinations yielding positive population growth rates in a community. We identify four ecological cases contributing to the emergence and persistence of functionally distinct species. First, environmental heterogeneity or alternative phenotypic designs can drive positive population growth of functionally distinct species. Second, sink populations with negative population growth can deviate from local fitness peaks and be functionally distinct. Third, species found at the margin of the fitness landscape can persist but be functionally distinct. Fourth, biotic interactions (positive or negative) can dynamically alter the fitness landscape. We offer examples of these four cases and guidelines to distinguish between them. In addition to these deterministic processes, we explore how stochastic dispersal limitation can yield functional distinctiveness. Our framework offers a novel perspective on the relationship between fitness landscape heterogeneity and the functional composition of ecological assemblages. © 2023 The Authors. Ecology Letters published by John Wiley & Sons Ltd.
    • White Matter Hyperintensity Volume and Amyloid-PET Synergistically Impact Memory Independent of Tau-PET in Older Adults Without Dementia

      Edwards, L.; Thomas, K.R.; Weigand, A.J.; Edmonds, E.C.; Clark, A.L.; Walker, K.S.; Brenner, E.K.; Nation, D.A.; Maillard, P.; Bondi, M.W.; et al. (IOS Press BV, 2023-07-18)
      Background: Alzheimer's disease (AD) and cerebrovascular disease are common, co-existing pathologies in older adults. Whether the effects of cerebrovascular disease and AD biomarkers on cognition are additive or synergistic remains unclear. Objective: To examine whether white matter hyperintensity (WMH) volume moderates the independent association between each AD biomarker and cognition. Methods: In 586 older adults without dementia, linear regressions tested the interaction between amyloid-β (Aβ) positron emission tomography (PET) and WMH volume on cognition, independent of tau-PET. We also tested the interaction between tau-PET and WMH volume on cognition, independent of Aβ-PET. Results: Adjusting for tau-PET, the quadratic effect of WMH interacted with Aβ-PET to impact memory. There was no interaction between either the linear or quadratic effect of WMH and Aβ-PET on executive function. There was no interaction between WMH volume and tau-PET on either cognitive measure. Conclusion: Results suggest that cerebrovascular lesions act synergistically with Aβ to affect memory, independent of tau, highlighting the importance of incorporating vascular pathology into biomarker assessment of AD. © 2023 - The authors. Published by IOS Press.
    • Enhanced thermoelectricity in Bi-sprayed bismuth sulphide particles

      Mulla, R.; Kiani, S.; White, A.O.; Dunnill, C.W.; Barron, A.R.; Arizona Institute for Resilient Environments and Societies (AIRES), University of Arizona (Elsevier Ltd, 2023-08-01)
      Bismuth sulphide (Bi2S3), an n-type semiconductor that critically demonstrates the Seebeck effect with Seebeck coefficients of about 300 μVK−1. However, its poor electrical conductivity makes it unsuitable for thermoelectric applications. In this study, we present a facile preparation method for fabricating Bi-sprayed Bi2S3 particles that alters their thermoelectric properties. Samples were created with differing Bi concentrations into the Bi2S3 compound to test for enhanced thermoelectric properties of the resulting Bi/Bi2S3 composites. The incorporation of excess Bi into Bi2S3 significantly improves the compound's electrical conductivity and optimises overall thermoelectric performance. The electrical conductivity of the Bi/Bi2S3 composites improved from 6.5 Scm−1 (for pristine Bi2S3) to 154 Scm−1 (for highest Bi added Bi2S3). Although the Seebeck coefficient of samples decreased with Bi incorporation, a high power factor (∼390 μWm−1K−2) has been achieved for an optimised composition of the composite. Incorporation of metallic Bi has led to an increase in the thermal conductivity of the samples, but the increase is not significant for the optimised composition of the composites where a high thermoelectric performance has been observed. Therefore, enhanced power factor and moderate thermal conductivity have resulted in a peak ZT value of 0.11 at room temperature. The strategy proposed here improves the thermoelectricity in Bi2S3 and shows excellent potential for developing better-performing thermoelectric compounds with excess elemental contents. © 2023
    • Partitioning the effects of habitat loss, hunting and climate change on the endangered Chacoan peccary

      Torres, R.; Kuemmerle, T.; Baumann, M.; Romero-Muñoz, A.; Altrichter, M.; Boaglio, G.I.; Cabral, H.; Camino, M.; Campos Krauer, J.M.; Cartes, J.L.; et al. (John Wiley and Sons Inc, 2023-05-24)
      Aim: Land-use change and overexploitation are major threats to biodiversity, and climate change will exert additional pressure in the 21st century. Although there are strong interactions between these threats, our understanding of the synergistic and compensatory effects on threatened species' range geography remains limited. Our aim was to disentangle the impact of habitat loss, hunting and climate change on species, using the example of the endangered Chacoan peccary (Catagonus wagneri). Location: Gran Chaco ecoregion in South America. Methods: Using a large occurrence database, we integrated a time-calibrated species distribution model with a hunting pressure model to reconstruct changes in the distribution of suitable peccary habitat between 1985 and 2015. We then used partitioning analysis to attribute the relative contribution of habitat change to land-use conversion, climate change and varying hunting pressure. Results: Our results reveal widespread habitat deterioration, with only 11% of the habitat found in 2015 considered suitable and safe. Hunting pressure was the strongest single threat, yet most habitat deterioration (58%) was due to the combined, rather than individual, effects of the three drivers we assessed. Climate change would have led to a compensatory effect, increasing suitable habitat area, yet this effect was negated by the strongly negative and interacting threats of land-use change and hunting. Main Conclusions: Our study reveals the central role of overexploitation, which is often neglected in biogeographic assessments, and suggests that addressing overexploitation has huge potential for increasing species' adaptive capacity in the face of climate and land-use change. More generally, we highlight the importance of jointly assessing extinction drivers to understand how species might fare in the 21st century. Here, we provide a simple and transferable framework to determine the separate and joint effects of three main drivers of biodiversity loss. © 2023 The Authors. Diversity and Distributions published by John Wiley & Sons Ltd.
    • Invasion genomics uncover complex introduction patterns of the globally invasive whitefly, Bemisia tabaci MED

      Li, H.; Wang, J.; Peng, Y.; Guo, C.; Qu, W.; Yang, N.; Zhu, Y.; Jeong, I.; Li, X.; Ghanim, M.; et al. (John Wiley and Sons Inc, 2023-07-04)
      Aim: The sweet potato whitefly, Bemisia tabaci MED is a globally invasive species that causes serious economic damage to agroecosystems. Despite the significant threat it poses to agricultural and economic crops worldwide, the global perspective of the invasion patterns and genetic mechanisms contributing to the success of this notorious pest is still poorly understood. The objective of this research was to enhance genome and population genetic analyses to better understand the intricate invasion patterns of B. tabaci MED. Location: Samples were collected in native (Spain, Croatia, Bosnia and Herzegovina, Cyprus, and Israel) and invaded regions (China, South Korea and North America). Methods: We first assembled a chromosome-scale reference genome of B. tabaci MED and then employed the restriction site-associated 2b-RAD method to genotype over 20,000 high-quality single-nucleotide polymorphisms from 29 geographical populations. Results: A reference genome of B. tabaci MED, with a size of 637.47 Mb, was available. The majority of the assembled sequences (99%) were anchored onto 10 linkage groups, with an N50 size of 58.76 Mb, representing a significant improvement over previous whitefly genome assemblies. We identified rapidly expanded gene families and positively selected genes, probably contributing to successful invasion and rapid adaptation to the new environment. Population genomics analysis showed that three highly differentiated genetic groups were formed, and complex and extensive gene flow occurred across the Mediterranean populations. The genetic admixture patterns in East Asia populations were distinct from those in North America, indicating that they had different source populations. Conclusions: The high-quality, chromosome-scale genome of B. tabaci MED offered opportunities for more comprehensive genome-wide studies and provided solid foundation to the complex introduction events and the differential invasiveness of B. tabaci MED worldwide. © 2023 The Authors. Diversity and Distributions published by John Wiley & Sons Ltd.
    • The role of ecosystem transpiration in creating alternate moisture regimes by influencing atmospheric moisture convergence

      Makarieva, A.M.; Nefiodov, A.V.; Nobre, A.D.; Baudena, M.; Bardi, U.; Sheil, D.; Saleska, S.R.; Molina, R.D.; Rammig, A.; Department of Ecology and Evolutionary Biology, University of Arizona (John Wiley and Sons Inc, 2023-02-18)
      The terrestrial water cycle links the soil and atmosphere moisture reservoirs through four fluxes: precipitation, evaporation, runoff, and atmospheric moisture convergence (net import of water vapor to balance runoff). Each of these processes is essential for sustaining human and ecosystem well-being. Predicting how the water cycle responds to changes in vegetation cover remains a challenge. Recently, changes in plant transpiration across the Amazon basin were shown to be associated disproportionately with changes in rainfall, suggesting that even small declines in transpiration (e.g., from deforestation) would lead to much larger declines in rainfall. Here, constraining these findings by the law of mass conservation, we show that in a sufficiently wet atmosphere, forest transpiration can control atmospheric moisture convergence such that increased transpiration enhances atmospheric moisture import and results in water yield. Conversely, in a sufficiently dry atmosphere increased transpiration reduces atmospheric moisture convergence and water yield. This previously unrecognized dichotomy can explain the otherwise mixed observations of how water yield responds to re-greening, as we illustrate with examples from China's Loess Plateau. Our analysis indicates that any additional precipitation recycling due to additional vegetation increases precipitation but decreases local water yield and steady-state runoff. Therefore, in the drier regions/periods and early stages of ecological restoration, the role of vegetation can be confined to precipitation recycling, while once a wetter stage is achieved, additional vegetation enhances atmospheric moisture convergence and water yield. Recent analyses indicate that the latter regime dominates the global response of the terrestrial water cycle to re-greening. Evaluating the transition between regimes, and recognizing the potential of vegetation for enhancing moisture convergence, are crucial for characterizing the consequences of deforestation as well as for motivating and guiding ecological restoration. © 2023 The Authors. Global Change Biology published by John Wiley & Sons Ltd.